A Comparative Study of the Effect of Non-Antibiotic Feed Additives on Experimental Colonization of Salmonella Enterica Serovar Enteridis and Intestinal Pathomorphology in Broiler Chickens

The objective of this study was to evaluate the effect of eubiotics on the intestinal morphology of broilers. For this purpose, 125 birds were divided into six groups with two replicates each (10 birds in each replicate). Group A was given a Basal diet. All groups except group A were challenged with Salmonella enterica serovar Enteritidis. Group B was provided the basal diet, group C was fed a Probiotic-added diet; group D was fed a Prebiotics-based diet; group E was given essential oils plus the basal diet; and group F was provided with organic acids plus the basal diet. Two separate experiments were carried out for Salmonella recovery, checking the cecal tonsils and conducting an intestinal pathomorphic evaluation. Villus length, villus width, villus surface area, and crypt depth were measured by micrometry. There was an overall improvement (p<0.05) in intestinal morphometric parameters for all the treatment groups except for the negative control group, which showed the lowest villus height and villus depth values. Maximum villus height (p<0.05) of the duodenum was achieved by group E, which was fed a diet containing essential oils, whereas a maximum villus surface area index (p<0.05) was recorded for the birds of Group D, which were fed a diet containing prebiotics. Maximum villus height (p<0.05) and surface area index in ileum mucosa was recorded (p<0.05) in the birds of group D (treated with prebiotics). It is concluded that there is an overall increase in the gut histology of broilers fed non-antibiotic based feed.(AU)

Prevalence and antimicrobial resistance of Salmonella spp isolated from free-ranging wild boars in the state of São Paulo, Brazil / Prevalência e resistência antimicrobiana de Salmonella spp isoladas em javalis de vida livre no estado de São Paulo

European wild boars (Sus scrofa) are considered exotic invasive species worldwide. Invasions of wild boars are a growing public health concern, as wild boars may represent an important reservoir of zoonotic pathogens, including bacteria of the genus Salmonella. The aim of this study was to determine the prevalence and serovars of Salmonella spp. in free-ranging wild boars legally hunted in the state of São Paulo, Brazil, and the susceptibility of those Salmonella spp. to antimicrobials. Fecal samples and mesenteric lymph nodes were acquired from 63 wild boars. The prevalence of Salmonella spp. in free-ranging wild boars was 9.5 % (6/63; confidence interval: 4.4 % - 19.2 %). Six serovars were isolated: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) and S. enterica ser. Muenster. Analysis of antimicrobial resistance of Salmonella spp. showed that the majority of serovars were fully susceptible to the tested antimicrobials. Only S. enterica ser. Typhimurium and S. enterica ser. Muenster showed a resistance pattern to at least one antimicrobial analyzed. To our knowledge, this study is the first report the prevalence and serovars of Salmonella spp. in free-ranging wild boars in the State of São Paulo, Brazil. Results indicate a low prevalence with variability of Salmonella serovars, with some pattern of antimicrobial resistance. This study highlights the potential role of wild boars as carriers of Salmonella and could pose a risk to wild and domestic animals as well as humans.

Os javalis europeus (Sus scrofa) são considerados uma espécie exótica invasora em todo o mundo. As invasões de javalis são uma preocupação crescente de saúde pública, pois os javalis podem representar um importante reservatório de patógenos zoonóticos, incluindo bactérias do gênero Salmonella. O objetivo deste estudo foi determinar a prevalência e os sorovares de Salmonella spp. em javalis de vida livre caçados legalmente no Estado de São Paulo, Brasil, e a suscetibilidade dessa Salmonella spp. aos antimicrobianos. Amostras fecais e linfonodos mesentéricos foram adquiridos de 63 javalis. A prevalência de Salmonella spp. em javalis selvagens foi de 9,5% (6/63; intervalo de confiança: 4,4% - 19,2%). Seis sorovares foram isolados: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) e S. enterica ser. Muenster. As análises de resistência antimicrobiana de Salmonella spp. evidenciaram que a maioria dos sorovares era pansensível aos antimicrobianos testados. Apenas S. enterica ser. Typhimurium e S. enterica ser. Muenster mostraram um padrão de resistência a pelo menos um antimicrobiano analisado. A saber, este estudo é o primeiro relato da prevalência e de sorovares de Salmonella spp. em javalis de vida livre no Estado de São Paulo, Brasil. Os resultados indicaram baixa prevalência com variabilidade de sorovares de Salmonella, com algum padrão de resistência antimicrobiana. Este estudo destaca o papel potencial dos javalis como portadores de Salmonella spp. e pode representar um risco para os animais domésticos e selvagens, bem como para os humanos.

Association between non-typhoidal Salmonella isolated from commercial poultry sheds and associated factors in Paraná, Brazil: Cross-sectional retrospective study

The epidemiology of salmonellosis in poultry is complex, which makes it difficult to identify the origin and spread of this disease in poultry farms. The aims of this study were to characterize the spatial distribution of Salmonella enterica in epidemiological units in Paraná, Brazil; and to investigate correlations between this microorganism and associated factors. Among the epidemiological units, 78 of 243 (32.10%) were positive. Spatially, the northwestern and western regions had higher concentrations of positive cases than the other regions. In bivariate analyses, the presence of other animal species in the epidemiological unit (prevalence ratio, PR = 0.64; 95% confidence interval, CI = 0.43­0.95; p = 0.022) and proximity to establishments at risk (PR = 0.51; 95% CI = 0.32­0.81; p = 0.001) did not influence positivity, but the average population per poultry shed (between 30,501 and 32,500; PR = 2.57; 95% CI = 1.72­3.83; p = 0.001) was associated with Salmonella positivity. Multiple logistic regression demonstrated that the average population per poultry shed, presence of surrounding risk-posing establishments and presence of surrounding poultry sheds produced a significant multiple model for S. enterica. The results indicated that the presence of S. enterica may be related to higher density broiler in poultry sheds, presence of surrounding poultry sheds, proximity between positive and negative epidemiological units and altitude of the municipality. The information obtained showed that some factors were related to positivity for this microorganism and emphasizes the importance of serotyping to obtain other epidemiological data.

Action of benzalkonium chloride in different pH

Ammonium quaternary compounds are widely used in poultry and swine production as disinfectants in the control of pathogens. They act on gram-positive bacteria, gram-negative bacteria, enveloped fungi and viruses. However, in some conditions of pH and presence of organic matter can be inactivated. This study evaluated the action of ammonium quaternary compounds at 1:1,000 and 1:2,000 dilutions against Salmonella enterica serovarTyphimurium and Salmonella enterica serovar Enteritidis in the presence of three different organic matter simulators, fetal bovine serum, skim milk and whole milk concentration of 1, 3, 5, and 7% and at pH 6 and 9, with 15 min of contact. It was possible to verify that the organic matter simulators adjusted in the same conditions of contact time and percentage, in the in vitro tests, presented different results and the fetal bovine serum did not inactivate the disinfectant. However, the best result against S. Typhimurium and S. Enteritidis was obtained at pH 6 at the dilution of 1:1,000 in all organic matter simulators.

Antimicrobial activity and chemical characterization of Laurel essential oil / Atividade antimicrobiana e caracterização química do óleo essencial de Louro / Actividad antimicrobiana y caracterización química del aceite esencial de Laurel

The factors that arouse interest in the study of essential oils as biocidal agents are numerous, such as the fact that they have antibacterial, antifungal, insecticidal, antioxidant, anti-inflammatory and larvicidal properties. The objective of this work was to evaluate the antimicrobial activity, in vitro, of the laurel (Laurus nobilis L) essential oil on the growth of pathogenic bacteria Salmonella enterica serovar Typhimurium ATCC 14028 and Staphylococcus aureus ATCC 25923, at different exposure times, as well as to perform the chemical characterization. Twenty compounds were identified and quantified, representing 96.57% of the total composition. The class of oxygenated monoterpenes represented the majority class of the essential oil, with 1,8-cineol (33.8%) as the substance found in greater quantity, followed by linalool (17.79%). The third constituent in greater quantity was sabinene (12.23%), belonging to the group of monoterpene hydrocarbons. Terpinyl acetate (9.41%) was also considered to be quantitatively representative. Laurel essential oil showed bacteriostatic activity against S. Typhimurium ATCC 14028 and S. aureus ATCC 25923.(AU)

Os fatores que despertam interesse no estudo dos óleos essenciais como agentes biocidas são inúmeros, como o fato de possuírem propriedades antibacteriana, antifúngica, inseticida, antioxidante, antiinflamatória e larvicida. O objetivo deste trabalho foi avaliar a atividade antimicrobiana, in vitro, do óleo essencial de louro (Laurus nobilis L) sobre o crescimento das bactérias patogênicas Salmonella enterica sorovar Typhimurium ATCC 14028 e Staphylococcus aureus ATCC 25923, em diferentes tempos de exposição, assim como realizar a caracterização química do óleo. Vinte compostos foram identificados e quantificados, representando 96,57% da composição total. A classe dos monoterpenos oxigenados representou a classe majoritária do óleo essencial, sendo o 1,8-cineol (33,8%) a substância encontrada em maior quantidade, seguido do linalol (17,79%). O terceiro constituinte em maior quantidade foi o sabineno (12,23%), pertencente ao grupo dos hidrocarbonetos monoterpênicos. O acetato de terpinila (9,41%) também foi considerado quantitativamente representativo. O óleo essencial de louro apresentou atividade bacteriostática contra S. Typhimurium ATCC 14028 e S. aureus ATCC 25923.(AU)

Los factores que despiertan interés en el estudio de los aceites esenciales como agentes biocidas son innumerables, como el hecho de que tienen propiedades antibacterianas, anti fúngicas, insecticidas, antioxidantes, antiinflamatorias y larvicidas. El objetivo de este trabajo ha sido evaluar la actividad antimicrobiana, in vitro, del aceite esencial de laurel (Laurus nobilis L) sobre el crecimiento de bacterias patógenas Salmonella enterica serovar Typhimurium ATCC 14028 y Staphylococcus aureus ATCC 25923, en diferentes momentos de exposición, así como realizar la caracterización química del aceite. Se identificaron y cuantificaron veinte compuestos, que representan el 96,57% de la composición total. La clase de mono terpenos oxigenados representó la clase principal de aceite esencial, siendo el 1,8-cineol (33,8%) la sustancia que se encuentra en mayor cantidad, seguida del linalol (17,79%). El tercer constituyente en mayor cantidad fue el sabineno (12,23%), perteneciente al grupo de los hidrocarburos monoterpénicos. El acetato de terpinilo (9,41%) también se consideró cuantitativamente representativo. El aceite esencial de laurel mostró actividad bacteriostática contra S. Typhimurium ATCC 14028 y S. aureus ATCC 25923.(AU)

Salmonelose em bezerros pelo sorovar Dublin no estado do Paraná, Brasil - aspectos clínico-patológicos / Salmonellosis in calves by serovar Dublin in Paraná State, Brazil - clinicopathological aspects

Background: Calf diarrhea remains one of the main diseases affecting the cattle industry. Persistence of this significant problem is associated with the complexity of factors that may be involved (infectious, environmental). An accurate diagnosis is essential for confirming the cause and helping clinicians and cattle producers to apply appropriate strategies in a timely manner. This report describes the histological changes according to the degree of salmonellosis severity, which is a contagious infectious disease caused by Salmonella enterica subsp. enterica, a Gram-negative bacterium, in two beef calves in northern Paraná State, southern Brazil. Cases: Two 90-day-old crossbred Angus and Nellore calves from a beef farm in northern Paraná State were referred to a Veterinary Hospital. Animal 1- developed acute clinical signs (enteritis, ataxia, and muscle rigidity) and died the day after the signs began. Gross findings included heavy and non-collapsed lungs, pulmonary oedema, hepatomegaly, enteritis, and severe diffuse typhlitis. Microscopic analysis revealed severe diffuse necrotic enteritis, typhlitis, severe diffuse interstitial pneumonia, moderate centrilobular hepatic necrosis, mild multifocal nephritis, and severe spleen and lymph node necrosis. Paratyphoid nodules were evidenced on the liver, spleen, and mesenteric lymph nodes. Animal 2- presented apathy, green fibrinous diarrhea, and died three days after the onset of clinical signs. The macroscopic examination showed moderate diffuse enteritis and hepatosplenomegaly. At the microscopic examination, many paratyphoid nodules were observed on the liver, spleen, kidneys, and Peyer's patches, which were associated with intralesional and intravascular bacilli. Additional findings included severe diffuse fibrinous necrotic enteritis with intralesional bacilli, diffuse interstitial pneumonia, multifocal splenic necrosis, lymphoid depletion, and moderate multifocal to coalescent lymphocytic nephritis. Histological Gram staining was performed on selected samples, revealing intralesional Gram-negative bacilli in the liver and intestine. Thus, liver and intestine fragments were used for the microbiological examination. Microbiological culture, isolation and biochemical tests identified the genus Salmonella spp. Then, the colonies were subjected to serological tests for serovar identification, according to ISO/TR 6579-3, which determined the serovar Dublin. After identifying the disease etiological agent, the outbreak was controlled by appropriate antibiotic therapy combined with the correction of sanitary measures. Discussion: Enteritis is a frequent disease in calves, posing a diagnostic challenge in identifying the etiological agent. In the present case, the histological, microbiological, and serological results confirmed a disseminated Salmonella spp. infection. The microscopic findings, such as interstitial pneumonia, fibrinous necrotic enteritis markedly in ileum and paratyphoid nodules in various organs, are the most common aspects of the disease. However, fibrinous cholecystitis, which is considered pathognomonic for salmonellosis, was not observed in this study. Therefore, the absence of such a lesion should not exclude the disease in sick animals. A microscopic injury score was used to determine lesion severity by assigning values from 1 to 4, wherein: 1 = no apparent lesions, 2 = mild lesions, 3 = moderate lesions, and 4 = severe lesions. Both calves were scored as 4. Multiple predisposing factors for the condition were identified in this farm such as different age animals in the same paddock and no specific paddock for sick animals, given that the infectious agent remains in feces, saliva, and nasal discharge. The serovar Dublin induces several clinical signs such as septicemic, respiratory, and enteric manifestations, making a clinical diagnosis a challenge

Diversity and antimicrobial resistance of Salmonellaentericaserovars in surface river water and sediment / Diversidade e resistência antimicrobiana de sorovares de Salmonella enterica em águas superficiais de rios e sedimentos

This study aimedto evaluate the contamination by Salmonellasp. in the Capinzal River, to determinethe prevalent serovars, patterns of antimicrobial resistance, and the genetic relationships between the serovars identified. A total of 108 samples were collected from 2016 to 2018. The isolation of Salmonellaspp. was conducted accordingto InternationalOrganization for Standardization (ISO) standards. The antimicrobial resistance profile of the Salmonella isolates was evaluated, and isolates were selected for serotyping and verification of genetic similarity using the Pulsed-FieldGel Electrophoresis (PFGE) Technique. Of the 108 samples collected, 35 (32.4%) were positive for Salmonella; 17.2% of the isolates were from the rural area; and 88.6% were from the urban area. Salmonellawas isolated from all collect points along the river, with a higher incidence at the beginning of the urban area, indicating that contamination starts in the rural area and intensifies in the urban area of the city. A percentageof 35.1% of the Salmonellaisolates were resistant to at least two antibiotics, while 18.9% were considered multidrug-resistant (resistant to at least two antibiotics of different classes). Seven serovars were distinguished from the serotyped isolates, with a prevalence rate of 23.5% for S.Infantis, S.Orion, and S. Javiana; 11.8% forS.Senfterberg, and 5.9% forS. Montevideo, S.Heidelberg, and S.entericasubsp. enterica(O: 6.8). The variability in specific restriction sites generated by PFGE resulted in 10 pulsotypes, separating mainly different serotypes.

O objetivo deste estudo foi avaliar a contaminação por Salmonellasp. no rio Capinzal, para determinar os sorovares prevalentes, padrões de resistência antimicrobiana e as relações genéticas entre os sorovaresidentificados. Um total de 108 amostras foram coletadas de 2016 a 2018. O isolamento de Salmonellaspp. foi conduzido de acordo com os padrões da International Organization for Standardization (ISO). O perfil de resistência antimicrobiana dos isolados de Salmonellafoi avaliado, e os isolados foram selecionados para sorotipagem e verificação de similaridade genética por meio da Técnica de Eletroforese em Gel de Campo Pulsado (PFGE). Das 108 amostras coletadas, 35 (32,4%) foram positivaspara Salmonella; 17,2% dos isolados eram da área rural; e 88,6% da área urbana. Salmonellafoi isolada em todos os pontos de coleta ao longo do rio, com maior incidência no início da área urbana, indicando que a contaminação começa na área rural e se intensifica na área urbana da cidade. Um percentual de 35,1%dos isolados de Salmonellaforam resistentes a pelo menos dois antibióticos, enquanto 18,9% foram considerados multirresistentes (resistentes a pelo menos dois antibióticos de classes diferentes). Sete sorovares foram diferenciadosdos isolados sorotipados, com uma taxa de prevalência de 23,5% para S.Infantis,S.Orion e S.Javiana; 11,8% para S.Senfterberg e 5,9% para S.Montevidéu, S.Heidelberg e S.enterica subsp. enterica (O: 6,8). A variabilidade emlocais de restrição específicos gerados por PFGE resultou em 10 pulsotipos, separando principalmente diferentes sorotipos.

Diversity and antimicrobial resistance of Salmonellaentericaserovars in surface river water and sediment / Diversidade e resistência antimicrobiana de sorovares de Salmonella enterica em águas superficiais de rios e sedimentos

This study aimedto evaluate the contamination by Salmonellasp. in the Capinzal River, to determinethe prevalent serovars, patterns of antimicrobial resistance, and the genetic relationships between the serovars identified. A total of 108 samples were collected from 2016 to 2018. The isolation of Salmonellaspp. was conducted accordingto InternationalOrganization for Standardization (ISO) standards. The antimicrobial resistance profile of the Salmonella isolates was evaluated, and isolates were selected for serotyping and verification of genetic similarity using the Pulsed-FieldGel Electrophoresis (PFGE) Technique. Of the 108 samples collected, 35 (32.4%) were positive for Salmonella; 17.2% of the isolates were from the rural area; and 88.6% were from the urban area. Salmonellawas isolated from all collect points along the river, with a higher incidence at the beginning of the urban area, indicating that contamination starts in the rural area and intensifies in the urban area of the city. A percentageof 35.1% of the Salmonellaisolates were resistant to at least two antibiotics, while 18.9% were considered multidrug-resistant (resistant to at least two antibiotics of different classes). Seven serovars were distinguished from the serotyped isolates, with a prevalence rate of 23.5% for S.Infantis, S.Orion, and S. Javiana; 11.8% forS.Senfterberg, and 5.9% forS. Montevideo, S.Heidelberg, and S.entericasubsp. enterica(O: 6.8). The variability in specific restriction sites generated by PFGE resulted in 10 pulsotypes, separating mainly different serotypes.(AU)

O objetivo deste estudo foi avaliar a contaminação por Salmonellasp. no rio Capinzal, para determinar os sorovares prevalentes, padrões de resistência antimicrobiana e as relações genéticas entre os sorovaresidentificados. Um total de 108 amostras foram coletadas de 2016 a 2018. O isolamento de Salmonellaspp. foi conduzido de acordo com os padrões da International Organization for Standardization (ISO). O perfil de resistência antimicrobiana dos isolados de Salmonellafoi avaliado, e os isolados foram selecionados para sorotipagem e verificação de similaridade genética por meio da Técnica de Eletroforese em Gel de Campo Pulsado (PFGE). Das 108 amostras coletadas, 35 (32,4%) foram positivaspara Salmonella; 17,2% dos isolados eram da área rural; e 88,6% da área urbana. Salmonellafoi isolada em todos os pontos de coleta ao longo do rio, com maior incidência no início da área urbana, indicando que a contaminação começa na área rural e se intensifica na área urbana da cidade. Um percentual de 35,1%dos isolados de Salmonellaforam resistentes a pelo menos dois antibióticos, enquanto 18,9% foram considerados multirresistentes (resistentes a pelo menos dois antibióticos de classes diferentes). Sete sorovares foram diferenciadosdos isolados sorotipados, com uma taxa de prevalência de 23,5% para S.Infantis,S.Orion e S.Javiana; 11,8% para S.Senfterberg e 5,9% para S.Montevidéu, S.Heidelberg e S.enterica subsp. enterica (O: 6,8). A variabilidade emlocais de restrição específicos gerados por PFGE resultou em 10 pulsotipos, separando principalmente diferentes sorotipos.(AU)

Epidemiological and pathological aspects of salmonellosis in cattle in southern Brazil / Aspectos epidemiológicos e patológicos de salmonelose em bovinos no Sul do Brasil

Salmonellosis is a bacterial disease that affects several domestic animal species, and is commonly diagnosed in cattle, horses, and pigs. This study aimed to describe the epidemiological and pathological findings of eleven cases of enteric salmonellosis and two cases of salmonellosis with pulmonary involvement in cattle in Rio Grande do Sul State, Brazil. Clinical signs included fever, yellow diarrhea, sometimes with blood streaks, and dyspnea, with a clinical course ranging from 1 to 30 days. Eight cases occurred as outbreaks, whereas five cases occurred individually. Risk factors included inadequate handling practices, such as overcrowded facilities and comorbidities, including anaplasmosis. The main gross finding of the enteric presentation was fibrinonecrotic enterocolitis, occasionally associated with button ulcers, mesenteric lymphadenomegaly, splenomegaly, cholecystitis and hepatomegaly. In addition, one steer with a chronic clinical progression presented severe segmental thickening of the ileum, associated with intestinal rupture and peritonitis. In the respiratory system, the main findings were reddened, non-collapsed lungs, with multifocal areas of atelectasis. The main microscopic findings were observed in the small and large intestines, and these were characterized by severe necrosis and mucosal ulceration, associated with marked inflammatory infiltrate of neutrophils and fibrin deposition intermixed by rod-shaped bacterial aggregates, and fibrosis, as well as interstitial pneumonia. Seven cases yielded positive bacterial cultures for Salmonella spp. and three serovars, namely Typhimurium, Dublin, and Panama were identified. All cases exhibited immunolabeling for Salmonella spp. using immunohistochemistry.(AU)

Salmonelose é uma doença bacteriana que afeta inúmeras espécies animais, especialmente os bovinos, os equinos e os suínos. O presente estudo teve como objetivo descrever os aspectos epidemiológicos e patológicos de onze casos de salmonelose entérica e dois de salmonelose pulmonar em bovinos no estado do Rio Grande do Sul, Brasil. Os sinais clínicos incluíram febre, diarreia amarelada, por vezes com estrias de sangue, anorexia, perda de peso e dispneia, com curso clínico que variou de um a 30 dias. Em oito casos, a doença ocorreu em forma de surtos e cinco foram individuais. Identificou-se fatores de risco relacionados ao manejo inadequado com os bovinos, como alta lotação, além de comorbidades associadas, como anaplasmose. Os principais achados macroscópicos da forma entérica consistiram em enterocolite fibrinonecrótica, por vezes associada a formação de úlceras botonosas, linfonodos mesentéricos e baço aumentados, colecistite e hepatomegalia. Ainda, um bovino com quadro clínico crônico apresentou acentuado espessamento segmentar da parede do íleo associado a ruptura intestinal e peritonite. Na forma respiratória, os principais achados incluíram pulmões não colabados, avermelhados, com áreas multifocais de atelectasia. Os principais achados microscópicos foram observados no intestino delgado e grosso e foram caracterizados por acentuada necrose e ulceração da mucosa, associada a acentuado infiltrado inflamatório de neutrófilos e deposição de fibrina entremeada por agregados bacterianos cocobacilares e fibrose, além de pneumonia intersticial. Sete casos foram positivos para Salmonella sp. no cultivo bacteriano, com identificação dos sorovares Typhimurium, Dublin e Panama. Ao exame imuno-histoquímico para Salmonella sp. todos os casos apresentaram marcação positiva nos órgãos avaliados.(AU)

Identification and antimicrobial resistance of Salmonella enterica isolated from live birds at commercial resellers / Identificação e resistência a antimicrobianos de Salmonella enterica isoladas de aves vivas em revendas comerciais

The objective of this study was to investigate the sanitary and management characteristics of live-bird resellers as well as identify and undertake an antigenic characterization of Salmonella enterica and its sensitivity to antimicrobials. Structured questionnaires were applied and 627 samples were collected from the cages, consisting 209 samples of excreta, 209 of feed and 209 drinker swabs. These were processed by conventional bacteriology. The obtained isolates were subjected to the susceptibility test and to 12 antimicrobial tests by the disk diffusion method. Of the studied resellers, 91.7% house Gallus gallus domesticus, together with other animal species; sell birds with little zoosanitary documentation; have unsatisfactory active surveillance; and use and sell antimicrobials indiscriminately. The presence of Salmonella enterica was detected in 1.4% (9/627) of the samples analyzed in the cages, with 1.9% (4/209) found in excreta, 0.95% (2/209) in feed and in 1.4% (3/209) in drinker swabs. These were characterized antigenically as Salmonella Heidelberg, Gallinarum, Risen, Ndolo, Saint Paul, Mbandaka and subsp enterica O:6,7. When susceptibility to antimicrobials was determined, 44.4% resistance (4/9) was detected for trimethoprim-sulfamethoxazole, 33.3% (3/9) for enrofloxacin, 22.2% (2/9) for ciprofloxacin, ceftiofur and amoxicillin and 11.1% (1/9) for tetracycline and fosfomycin. Salmonella Heidelberg, as well as serovars Gallinarum, Risen, Saint Paul and Mbandaka, showed resistance to at least one of the tested antimicrobials. Trimethoprim-sulfamethoxazole and enrofloxacin were the antimicrobials that showed the least efficacy. Serovars such as Heidelberg, Gallinarum and Mbandaka have multiresistance to antimicrobials commonly used in human and veterinary medicine, implying potential risks to One Health.

Objetivou-se com este trabalho investigar as características sanitárias e de manejo das revendas de aves vivas, bem como a identificação e caracterização antigênica de Salmonella enterica e sua sensibilidade a antimicrobianos. Foram aplicados questionários estruturados, além de 627 amostras coletadas nas gaiolas, sendo 209 de excretas, 209 de ração e 209 suabes de bebedouros. Essas amostras foram processadas por bacteriologia convencional. Os isolados obtidos foram submetidos ao teste de suscetibilidade e a 12 antimicrobianos pelo método de difusão em disco. Verificou-se que 91,7% das revendas estudadas alojam Gallus gallus domesticus juntamente a outras espécies animais, comercializam aves com escassa documentação zoosanitária, a vigilância ativa é insatisfatória e utilizam e comercializam antimicrobianos de forma indiscriminada. Detectou-se a presença da Salmonella enterica em 1,4% (9/627) das amostras analisadas nas gaiolas, sendo 1,9% (4/209) em excretas, 0,95% (2/209) em ração e em 1,4% (3/209) em suabes de bebedouros, as quais foram caracterizadas, antigenicamente, como Salmonella Heidelberg, Gallinarum, Risen, Ndolo, Saint Paul, Mbandaka e subesp enterica O:6,7. Na determinação da suscetibilidade aos antimicrobianos, obteve-se resistência de 44,4% (4/9) para Trimetoprim-sulfametoxazol, 33,3% (3/9) para enrofloxacina, 22,2% (2/9) para ciprofloxacina, ceftiofur, amoxicilina e 11,1% (1/9) para tetraciclina e fosfomicina. Salmonella Heidelberg, além dos sorovares Gallinarum, Risen, Saint Paul e Mbandaka, todos mostraram resistência a pelo menos um dos antimicrobianos testados. Trimetoprim-sulfametoxazol e enrofloxacina foram os antimicrobianos que apresentaram menor eficácia. Sorovares como Heidelberg, Gallinarum e Mbandaka apresentam multirresistência aos antimicrobianos de uso comum em medicina humana e veterinária, o que implica em riscos potenciais para saúde única.

Identification and antimicrobial resistance of Salmonella enterica isolated from live birds at commercial resellers / Identificação e resistência a antimicrobianos de Salmonella enterica isoladas de aves vivas em revendas comerciais

The objective of this study was to investigate the sanitary and management characteristics of live-bird resellers as well as identify and undertake an antigenic characterization of Salmonella enterica and its sensitivity to antimicrobials. Structured questionnaires were applied and 627 samples were collected from the cages, consisting 209 samples of excreta, 209 of feed and 209 drinker swabs. These were processed by conventional bacteriology. The obtained isolates were subjected to the susceptibility test and to 12 antimicrobial tests by the disk diffusion method. Of the studied resellers, 91.7% house Gallus gallus domesticus, together with other animal species; sell birds with little zoosanitary documentation; have unsatisfactory active surveillance; and use and sell antimicrobials indiscriminately. The presence of Salmonella enterica was detected in 1.4% (9/627) of the samples analyzed in the cages, with 1.9% (4/209) found in excreta, 0.95% (2/209) in feed and in 1.4% (3/209) in drinker swabs. These were characterized antigenically as Salmonella Heidelberg, Gallinarum, Risen, Ndolo, Saint Paul, Mbandaka and subsp enterica O:6,7. When susceptibility to antimicrobials was determined, 44.4% resistance (4/9) was detected for trimethoprim-sulfamethoxazole, 33.3% (3/9) for enrofloxacin, 22.2% (2/9) for ciprofloxacin, ceftiofur and amoxicillin and 11.1% (1/9) for tetracycline and fosfomycin. Salmonella Heidelberg, as well as serovars Gallinarum, Risen, Saint Paul and Mbandaka, showed resistance to at least one of the tested antimicrobials. Trimethoprim-sulfamethoxazole and enrofloxacin were the antimicrobials that showed the least efficacy. Serovars such as Heidelberg, Gallinarum and Mbandaka have multiresistance to antimicrobials commonly used in human and veterinary medicine, implying potential risks to One Health.(AU)

Objetivou-se com este trabalho investigar as características sanitárias e de manejo das revendas de aves vivas, bem como a identificação e caracterização antigênica de Salmonella enterica e sua sensibilidade a antimicrobianos. Foram aplicados questionários estruturados, além de 627 amostras coletadas nas gaiolas, sendo 209 de excretas, 209 de ração e 209 suabes de bebedouros. Essas amostras foram processadas por bacteriologia convencional. Os isolados obtidos foram submetidos ao teste de suscetibilidade e a 12 antimicrobianos pelo método de difusão em disco. Verificou-se que 91,7% das revendas estudadas alojam Gallus gallus domesticus juntamente a outras espécies animais, comercializam aves com escassa documentação zoosanitária, a vigilância ativa é insatisfatória e utilizam e comercializam antimicrobianos de forma indiscriminada. Detectou-se a presença da Salmonella enterica em 1,4% (9/627) das amostras analisadas nas gaiolas, sendo 1,9% (4/209) em excretas, 0,95% (2/209) em ração e em 1,4% (3/209) em suabes de bebedouros, as quais foram caracterizadas, antigenicamente, como Salmonella Heidelberg, Gallinarum, Risen, Ndolo, Saint Paul, Mbandaka e subesp enterica O:6,7. Na determinação da suscetibilidade aos antimicrobianos, obteve-se resistência de 44,4% (4/9) para Trimetoprim-sulfametoxazol, 33,3% (3/9) para enrofloxacina, 22,2% (2/9) para ciprofloxacina, ceftiofur, amoxicilina e 11,1% (1/9) para tetraciclina e fosfomicina. Salmonella Heidelberg, além dos sorovares Gallinarum, Risen, Saint Paul e Mbandaka, todos mostraram resistência a pelo menos um dos antimicrobianos testados. Trimetoprim-sulfametoxazol e enrofloxacina foram os antimicrobianos que apresentaram menor eficácia. Sorovares como Heidelberg, Gallinarum e Mbandaka apresentam multirresistência aos antimicrobianos de uso comum em medicina humana e veterinária, o que implica em riscos potenciais para saúde única.(AU)

Investigation of Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica in pig carcasses in Southern Brazil / Pesquisa de Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica em carcaças de suínos no sul do Brasil

The intensification of pig production and advances in the sanitary control of herds profoundly changed the profile of risk attributed to pork consumption. In the actual scenario, most microorganisms related to macroscopic lesions observed in the post mortem inspection are not transmitted by food, while foodborne bacteria of importance to consumer health do not cause macroscopic lesions. In Brazil, the "Ministério da Agricultura, Pecuária e Abastecimento" requested a scientific opinion on the prioritizing of pathogens potentially transmitted by unprocessed pork. After conducting a qualitative risk assessment, only Salmonella enterica was classified as of high risk to consumers. The present study was part of the validation step of the risk assessment and aimed to investigate the frequency of S. enterica, Yersinia enterocolitica and Listeria monocytogenes and hygienic-sanitary indicators in pig carcasses of pigs rose under intensive production and slaughtered under the Federal Inspection System in three slaughterhouses located in Southern Brazil. Additionally, the antimicrobial resistance profile of the isolated pathogens was also investigated. A total of 378 carcasses were sampled by superficial sponges before the chilling step in three slaughterhouses. Samples were investigated for the presence of the three aforementioned pathogens and subjected to enumeration of Colony Formation Units (log CFU.cm-1) of total aerobic mesophiles (TAM) and Enterobacteriaceae. Salmonella strains were tested by disc diffusion test for resistance to eleven antimicrobials. There were significantly statistical differences (p<0.0001) on the median counts of both indicators between the slaughterhouses. The median of TAM was very close for Slaughterhouses A and B: 1.573 log CFU.cm-1 and 1.6014 log CFU.cm-1, respectively. While in Slaughterhouse C, a higher TAM median was detected (2.216 log CFU.cm-1). A similar profile was observed regarding to Enterobacteriaceae, and medians were calculated as follow: -0.426 log CFU.cm-1 in Slaughterhouse A; 0.2163 log CFU.cm-1 in B; and 0.633 log CFU.cm-1 in C. Regarding the pathogens investigated, L. monocytogenes was not detected and only one carcass from Slaughterhouse C was positive for Y. enterocolitica. Thus, the results suggest a very low prevalence of L. monocytogenes and Y. enterocolitica in the sampled population. A total of 65 (17.2%) carcasses were positive for S. enterica, with a difference in frequencies between slaughterhouses and slaughter days. The prevalence of Salmonella positive carcasses was higher in the Slaughterhouse C (25.4%; CI 95% 19-32%) in comparison with A (9.5%; CI 95% 9-14%) and B (18.3%; CI 95% 12-24%). There was no significantly statistical association between Enterobacteriaceae counts and Salmonella isolation on carcass surface (p=0.69). The slaughtering day, nested within the slaughterhouse, explains 31.3% of Salmonella prevalence variability. S. Typhimurium (38.1%) was the most prevalent, followed by S. Infantis (30.1%). Among the 61 Salmonella strains tested for resistance to antimicrobials, 18 (31.6%) were full-susceptible. No strain displayed resistance to azithromycin, ceftazidime, cefotaxime and meropenem. The highest resistance frequency was displayed to tetracycline (54.1%), followed by ampicillin (50.82%), nalidixic acid (42.62%) and chloramphenicol (42.62). Multi-resistance was detected in 52.54% of the, strains. In conclusion, S. enterica is more prevalent in pre-chill pig carcasses than Y. enterocolitica and L. monocytogenes and thus should be prioritized in monitoring and control programs at slaughter. Salmonella serovars varied among slaughterhouses and present significant differences in their resistance to antimicrobials. Slaughterhouses that present higher medians of TAM or Enterobacteriaceae in a monitoring period may have higher S. enterica prevalences as well. However, there is a high variation of S. enterica prevalence among slaughter days, which cannot be always related to the hygienic indicators counts observed on a given day.(AU)

A intensificação da produção de suínos e os avanços no controle sanitário dos rebanhos alterou de forma importante o perfil de risco do consumo de carne suína. No cenário atual, a maioria dos microrganismos causadores de lesões macroscópicas detectáveis na inspeção post mortem não são transmissíveis por alimentos, enquanto bactérias de importância como causadoras de doenças transmitidas por alimentos não causam lesões macroscópicas. No Brasil, o Ministério da Agricultura, Pecuária e Abastecimento solicitou uma opinião científica sobre a priorização de patógenos potencialmente transmitidos pela carne suína in natura. Após conduzir uma avaliação de risco qualitativa, apenas Salmonella enterica foi classificada como de alto risco para o consumidor. O presente estudo foi parte da etapa de validação da avaliação de risco e objetivou: investigar a frequência de S. enterica, Yersinia enterocolitica e Listeria. monocytogenes; e enumerar indicadores higiênico-sanitários em carcaças de suínos abatidos sob inspeção federal em frigoríficos dedicados ao abate de suínos sob sistema intensivo de criação no sul do Brasil. Além disso, o perfil de resistência a antimicrobianos dos patógenos isolados foi investigado. A superfície de um total de 378 carcaças foi amostrada por esponjas, na etapa de pré-resfriamento em três matadouros frigoríficos (A, B, C). As amostras foram investigadas quanto à presença dos três patógenos acima mencionados e quanto à enumeração de Unidades Formadoras de Colônia (log UFC.cm-1) de mesófilos aeróbios totais (MAT) e Enterobacteriaceae. As cepas isoladas de Salmonella foram testadas quanto à resistência a onze antimicrobianos pela técnica de disco difusão. As medianas de contagem de ambos os indicadores apresentaram diferença significativa (p<0,0001) entre matadouros-frigoríficos. A mediana de MAT foi bastante próxima para A e B (1,573 log UFC.cm-1 e 1,6014 log UFC.cm-1, respectivamente), enquanto em C uma mediana de MAT mais elevada foi determinada (2,216 log CFU.cm-1). Um perfil semelhante foi observado em relação a Enterobacteriaceae, sendo as medianas calculadas para A, B e C, respectivamente: -0,426 log CFU.cm-1; 0,2163 log UFC.cm-1; e 0,633 log UFC.cm-1. Em relação aos patógenos investigados, L. monocytogenes não foi detectada e apenas uma carcaça, do Matadouro C, foi positiva para Y. enterocolitica. Portanto, os resultados sugerem uma prevalência muito baixa desses patógenos na população amostrada. Em um total de 65 (17,2%) carcaças houve isolamento de S. enterica, com diferença nas frequências observadas entre matadouros e dias de abate. A prevalência de carcaças positivas para S. enterica foi maior no Matadouro C (25,4%; IC95% 19-32%) em comparação com A (9,5%; IC95% 9-14%) e B (18,3%; IC95% 12-24%). Não houve associação estatística entre o número de Enterobacteriaceae e o isolamento de S. enterica na superfície das carcaças (p=0,69). O dia de abate agrupado por frigorífico explica 31,3% da variação na prevalência de Salmonella. O sorovar mais frequente de S. enterica foi Typhimurium (38,1%) seguido de S. Infantis (30,1%). Entre as 61 cepas de S. enterica testadas quanto à resistência a antimicrobianos, 18 (31,6%) foram totalmente suscetíveis aos antimicrobianos testados. Nenhuma cepa apresentou resistência a azitromicina, ceftazidima, cefotaxima e meropenem. As maiores frequências de resistência foram demonstradas contra tetraciclina (54,1%), ampicilina (50,8%), ácido nalidíxico (42,62%) e cloranfenicol (42,62%). Em 52,54% das cepas foi detectada multi-resistência. Em conclusão, S. enterica é mais prevalente em carcaças suínas no pré-resfriamento do que Y. enterocolitica e L. monocytogenes. Portanto, S. enterica deve ser priorizada em programas de monitoramento e controle ao abate. Os sorovares de Salmonella variam entre matadouros e apresentam diferenças significativas na resistência a antimicrobianos. Matadouros de suínos que apresentam medianas de MAT e Enterobacteriaceae num período de monitoramento podem apresentar também prevalências mais de altas de presença de S. enterica. Entretanto, há uma alta variabilidade na frequência de S. enterica entre dias de abate, e nem sempre há relação entre essa frequência e a contagem de indicadores higiênico-sanitários determinados num determinado dia.(AU)

Investigation of Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica in pig carcasses in Southern Brazil / Pesquisa de Listeria monocytogenes, Salmonella enterica and Yersinia enterocolitica em carcaças de suínos no sul do Brasil

The intensification of pig production and advances in the sanitary control of herds profoundly changed the profile of risk attributed to pork consumption. In the actual scenario, most microorganisms related to macroscopic lesions observed in the post mortem inspection are not transmitted by food, while foodborne bacteria of importance to consumer health do not cause macroscopic lesions. In Brazil, the "Ministério da Agricultura, Pecuária e Abastecimento" requested a scientific opinion on the prioritizing of pathogens potentially transmitted by unprocessed pork. After conducting a qualitative risk assessment, only Salmonella enterica was classified as of high risk to consumers. The present study was part of the validation step of the risk assessment and aimed to investigate the frequency of S. enterica, Yersinia enterocolitica and Listeria monocytogenes and hygienic-sanitary indicators in pig carcasses of pigs rose under intensive production and slaughtered under the Federal Inspection System in three slaughterhouses located in Southern Brazil. Additionally, the antimicrobial resistance profile of the isolated pathogens was also investigated. A total of 378 carcasses were sampled by superficial sponges before the chilling step in three slaughterhouses. Samples were investigated for the presence of the three aforementioned pathogens and subjected to enumeration of Colony Formation Units (log CFU.cm-1) of total aerobic mesophiles (TAM) and Enterobacteriaceae. Salmonella strains were tested by disc diffusion test for resistance to eleven antimicrobials. There were significantly statistical differences (p<0.0001) on the median counts of both indicators between the slaughterhouses. The median of TAM was very close for Slaughterhouses A and B: 1.573 log CFU.cm-1 and 1.6014 log CFU.cm-1, respectively. While in Slaughterhouse C, a higher TAM median was detected (2.216 log CFU.cm-1)...(AU)

A intensificação da produção de suínos e os avanços no controle sanitário dos rebanhos alterou de forma importante o perfil de risco do consumo de carne suína. No cenário atual, a maioria dos microrganismos causadores de lesões macroscópicas detectáveis na inspeção post mortem não são transmissíveis por alimentos, enquanto bactérias de importância como causadoras de doenças transmitidas por alimentos não causam lesões macroscópicas. No Brasil, o Ministério da Agricultura, Pecuária e Abastecimento solicitou uma opinião científica sobre a priorização de patógenos potencialmente transmitidos pela carne suína in natura. Após conduzir uma avaliação de risco qualitativa, apenas Salmonella enterica foi classificada como de alto risco para o consumidor. O presente estudo foi parte da etapa de validação da avaliação de risco e objetivou: investigar a frequência de S. enterica, Yersinia enterocolitica e Listeria. monocytogenes; e enumerar indicadores higiênico-sanitários em carcaças de suínos abatidos sob inspeção federal em frigoríficos dedicados ao abate de suínos sob sistema intensivo de criação no sul do Brasil. Além disso, o perfil de resistência a antimicrobianos dos patógenos isolados foi investigado. A superfície de um total de 378 carcaças foi amostrada por esponjas, na etapa de pré-resfriamento em três matadouros frigoríficos (A, B, C). As amostras foram investigadas quanto à presença dos três patógenos acima mencionados e quanto à enumeração de Unidades Formadoras de Colônia (log UFC.cm-1) de mesófilos aeróbios totais (MAT) e Enterobacteriaceae. As cepas isoladas de Salmonella foram testadas quanto à resistência a onze antimicrobianos pela técnica de disco difusão. As medianas de contagem de ambos os indicadores apresentaram diferença significativa (p<0,0001) entre matadouros-frigoríficos. A mediana de MAT foi bastante próxima para A e B (1,573 log UFC.cm-1 e 1,6014 log UFC.cm-1, respectivamente),...(AU)

Survival assessment of Salmonella enterica in inoculated pork salami / Avaliação da sobrevivência de Salmonella enterica inoculada em salame de carne suína

Pork salami is an embedded, cured and ripened product commonly consumed in Brazil, and the presence of Salmonella enterica has already been reported in this product. During its preparation, the microbiological safety depends on the meat quality, addition of ingredients with antimicrobial activity, hygiene during processing, pH and water activity (Aw) reduction during maturation. In Brazil, the maturation protocol has not been determined in food regulation; therefore, the objectives of this study were (a) to identify the fermentation and drying phases during salami maturation; (b) to test the survival of S. enterica during salami processing; and (c) to compare xylose lysine deoxycholate (XLD) and thin agar layer (TAL) agar for recovering Salmonella. The salami samples were prepared with a cocktail of S. enterica strains, fermented at 30°C and dried at 20°C with controlled relative humidity (RH). Periodic sampling for S. enterica quantification and Aw and pH analyses were performed during maturation, and curves were constructed. Fermentation occurred during the first 66 hours, and the pH decreased while the population of S. enterica increased over the first 21 hours. The drying step was able to reduce the bacterial population by approximately 5 log CFU after 875 hours, reaching an Aw of less than 0.78. However, elimination of S. enterica was not achieved. For Salmonella recovery, TAL agar was more efficient than XLD agar.(AU)

O salame de carne suína é um produto embutido, curado e maturado comumente consumido no Brasil no qual a presença de Salmonella enterica tem sido relatada. Durante a sua elaboração, a segurança microbiológica depende da qualidade da carne, adição de ingredientes com atividade antimicrobiana, higiene durante a produção, redução de pH e atividade de água (Aw) durante a sua maturação. O protocolo de maturação ainda não está determinado na legislação brasileira; portanto o estudo objetivou: (a) identificar as fases de fermentação e dessecação durante a maturação de salame; (b) testar a sobrevivência de S. enterica durante o processamento de salame e (c) comparar os meios de cultura xilose lisina dextrose (XLD) e thin agar layer (TAL) para recuperação de células do referido microorganismo. Os salames foram elaborados com um coquetel de S. enterica e submetidos à fermentação em 30ºC e secagem a 20ºC com umidade relativa (UR) controlada. Amostragens periódicas para quantificação de S. enterica, análises de Aw e pH foram realizadas durante a maturação e as curvas foram construídas. A fermentação ocorreu nas primeiras 66 horas, quando houve queda do pH do salame; entretanto S. enterica aumentou sua população nas primeiras 21 horas. A etapa de dessecação foi capaz de reduzir aproximadamente 5 log UFC da população bacteriana em 875 horas, alcançando Aw menor que 0,78, mas não foi capaz de eliminar o micro-organismo do alimento. Para enumeração do micro-organismo, o meio sólido TAL foi mais eficiente na recuperação das células submetidas à maturação quando comparado ao ágar XLD comumente utilizado.(AU)

Behavior of spoilage bacteria and Salmonella enterica subspecies enterica O: 4, 5 in vacuum-packaged beef during refrigeration / Comportamento de bactérias deteriorantes e Salmonella enterica subespécie entérica O: 4, 5 em carne bovina embalada a vácuo durante refrigeração

In this study, the kinetic parameters of mesophilic, psychrotrophic and lactic acid bacteria in vacuum-packed beef at 1 °C and 4 °C were estimated from experimental growth curves produced by samples stored during 21 and 60 days, respectively. In a separate experiment, the survival of multidrug resistant (MDR) Salmonella enterica O:4,5 at 1°C was also characterized. The shelf-life of vacuum-packed beef stored at 4 °C was estimated at 16.1 days (95% CI: 14.8 - 17.3 days), whereas at 1 °C it was longer than 21 days because the mesophiles count estimated towards the end of the experiment was 12.5 ln CFU.g-1 (95% CI: 11.8 - 13.3 ln CFU.g-1) which is lower than the shelf-life reference value. At 1 °C, inoculated Salmonella was reduced in 6.61 ln CFU.g-1 (2.87 log CFU.g-1). These results demonstrated the importance of establishing in legislation, especially in Brazil, standard values of deteriorating microorganisms in beef for maintaining product quality.(AU)

Neste estudo, os parâmetros cinéticos de bactérias mesófilas, psicrotróficas e ácido lácticas foram estimados em carne bovina embalada a vácuo a 1 °C e 4 °C, a partir de curvas experimentais produzidas em amostras estocadas durante 21 e 60 dias, respectivamente. Em um experimento separado, a sobrevivência de Salmonella enterica O:4,5 multirresistente (MDR) a 1°C também foi caracterizada. A vida de prateleira da carne bovina embalada a vácuo, estocada a 4°C, foi estimada em 16.1 dias (95% CI: 14.8 - 17.3 dias), enquanto que a 1 °C o período foi maior que 21 dias, porque a contagem estimada de mesófilos ao final do experimento foi de 12.5 ln UFC.g-1 (95% CI: 11.8 - 13.3 ln UFC.g-1), o qual é mais baixo que o valor referência de shelf-life. A 1 °C, Salmonella inoculada reduziu em 6.61 ln UFC.g-1 (2.87 log UFC.g-1). Estes resultados demonstram a importância de estabelecimento em legislação, especialmente no Brasil, de valores padrões para contagem de microrganismos deteriorantes em carnes visando manter a qualidade do produto.(AU)

Avaliação da capacidade de formação de biofilme de Salmonella enterica em superfícies de vidro frente à variações de temperatura, pH e concentração de NaCl / Evaluation of biofilm formation capacity of Salmonella enterica on glass surfaces as a function of temperature, pH and concentration of NaCl

Os biofilmes de patógenos são comumente relacionados a problemas de saúde pública, pois são fontes crônicas de contaminação de alimentos. Este estudo teve como objetivo avaliar a capacidade de formação de biofilme de Salmonella enterica em superfícies de vidro sob distintas condições de osmolaridade, temperatura e potencial de hidrogênio (pH). Os resultados obtidos destacam a variabilidade entre os sorovares quanto a capacidade de formação de biofilme nas condições ambientais estudadas. Observou-se que pH 4,5, concentrações de NaCl > 4,5% e temperaturas ≤ 15°C inibem a capacidade de formação de biofilme dos sorovares de S. enterica avaliadas. Conclui-se, que estudos que avaliam a formação de biofilme em superfícies comumente utilizadas na indústria e/ou serviços de alimentação e nutrição são instrumentos importantes na avaliação de riscos e adoção de medidas preventivas contra a formação de biofilme de patógenos.(AU)

Avaliação da capacidade de formação de biofilme de Salmonella enterica em superfícies de vidro frente à variações de temperatura, pH e concentração de NaCl / Evaluation of biofilm formation capacity of Salmonella enterica on glass surfaces as a function of temperature, pH and concentration of NaCl

Os biofilmes de patógenos são comumente relacionados a problemas de saúde pública, pois são fontes crônicas de contaminação de alimentos. Este estudo teve como objetivo avaliar a capacidade de formação de biofilme de Salmonella enterica em superfícies de vidro sob distintas condições de osmolaridade, temperatura e potencial de hidrogênio (pH). Os resultados obtidos destacam a variabilidade entre os sorovares quanto a capacidade de formação de biofilme nas condições ambientais estudadas. Observou-se que pH 4,5, concentrações de NaCl > 4,5% e temperaturas ≤ 15°C inibem a capacidade de formação de biofilme dos sorovares de S. enterica avaliadas. Conclui-se, que estudos que avaliam a formação de biofilme em superfícies comumente utilizadas na indústria e/ou serviços de alimentação e nutrição são instrumentos importantes na avaliação de riscos e adoção de medidas preventivas contra a formação de biofilme de patógenos.

Antimicrobial Resistance and Molecular Characterization of Salmonella Enterica Serotypes Isolated from Poultry Sources in Brazil

Salmonella spp. remain among the most important agents of foodborne diseases worldwide. The importance of Salmonella spp. in public health is linked to their wide range of antimicrobial resistance and to their pathogenicity and virulence in both human and animal hosts. The aim of this study was to determine the antimicrobial resistance patterns for Salmonella serotypes isolated from poultry sources in Brazil and to detect virulence-associated genes and verify their association with specific serotypes. A total of 163 strains of Salmonella enterica isolated from poultry sources in Southern Brazil were selected, and each belonged to one of 11 different serotypes. They were tested against ten antibiotics and examined for the presence of 26 virulence-associated genes by PCR. S. Typhimurium, S. Bredeney, S. Schwarzengrund and S. Tennessee showed the highest overall resistance rates. Approximately 18% of Salmonella strains were classified as multidrug-resistant strains. Our results indicate associations between antimicrobial resistance and specific serotypes. Most of the investigated genes presented a high frequency and a regular distribution, regardless of the serotype. Eight genes are positively or negatively associated with at least one serotype. The observed associations between antimicrobial resistance and specific serotypes are useful in developing specific control and treatment measures for each serotype. Despite the virulence genes being evenly distributed among the serotypes, some of these genes are associated with specific serotypes, and sefA, sopEand lpfA were selected as possible markers of Salmonella serotypes.(AU)

Antimicrobial Resistance and Molecular Characterization of Salmonella Enterica Serotypes Isolated from Poultry Sources in Brazil

Salmonella spp. remain among the most important agents of foodborne diseases worldwide. The importance of Salmonella spp. in public health is linked to their wide range of antimicrobial resistance and to their pathogenicity and virulence in both human and animal hosts. The aim of this study was to determine the antimicrobial resistance patterns for Salmonella serotypes isolated from poultry sources in Brazil and to detect virulence-associated genes and verify their association with specific serotypes. A total of 163 strains of Salmonella enterica isolated from poultry sources in Southern Brazil were selected, and each belonged to one of 11 different serotypes. They were tested against ten antibiotics and examined for the presence of 26 virulence-associated genes by PCR. S. Typhimurium, S. Bredeney, S. Schwarzengrund and S. Tennessee showed the highest overall resistance rates. Approximately 18% of Salmonella strains were classified as multidrug-resistant strains. Our results indicate associations between antimicrobial resistance and specific serotypes. Most of the investigated genes presented a high frequency and a regular distribution, regardless of the serotype. Eight genes are positively or negatively associated with at least one serotype. The observed associations between antimicrobial resistance and specific serotypes are useful in developing specific control and treatment measures for each serotype. Despite the virulence genes being evenly distributed among the serotypes, some of these genes are associated with specific serotypes, and sefA, sopEand lpfA were selected as possible markers of Salmonella serotypes.

Enumeration, antimicrobial resistance and typing of Salmonella enterica: profile of strains carried in the intestinal contents of pigs at slaughter in Southern Brazil

Background: Despite a strong association between Salmonella isolation and slaughter hygiene, as measured by the Enterobacteriaceae levels on pre-chill carcass surfaces, a high variation in this association was observed between sampling dayswithin the same slaughterhouse. It was hypothesised that in a scenario of high exposure on the farm, batches with a highprevalence of carrier pigs shedding a high number of Salmonella may enhance the risk of contamination on some slaughterdays. Thus, the aim of this study was to assess the profile of Salmonella carried in the intestinal contents of slaughter pigs.Materials, Methods & Results: Ten pig batches slaughtered in a slaughterhouse were investigated for the presence ofSalmonella. From each pig, the following samples were taken: i. blood collected at bleeding; ii. sponges rubbed on thecarcass surface after bleeding and before chilling; iii. fragment of the ileocecal region of the intestine. Serum sampleswere subjected to a ELISA-Typhimurium test. Sponges were investigated for the presence of Salmonella and total aerobicmesophilic (TAM) and Enterobacteriaceae (EC) bacterial counts. Salmonella was enumerated in the intestinal contents.Selected Salmonella strains were subjected to an antimicrobial resistance disk diffusion test, macro-restriction with Xba-I(PFGE) and whole genome sequencing (WGS). From the 50 sampled pigs, 96% were positive in the ELISA-Typhimuriumtest and 64% were Salmonella-positive in the intestinal contents. The amount of Salmonella in the intestinal content sampleswas highly variable, and the mean log of fitted distributions of Salmonella in the batch ranged from -2.97 to 2.25 cfu.g-1.The slaughter process achieved a logarithmic reduction, ranging from 0.64 to 2.35 log cfu.cm-2 for TAM and from 0.55 to2.57 log cfu.cm-2 for EC. Salmonella was isolated from 16% of the carcasses after bleeding; this frequency decreased to8% at the pre-chill...