Detection and Antimicrobial Resistance Profile of Enteropathogenic (EPEC) and Shigatoxigenic Escherichia coli (STEC) in Conventional and Organic Broiler Chickens

Enteropatogenic Escherichia coli (EPEC) and shigatoxigenic E. coli (STEC), are generally poultry and poultry product isolate and can cause serious human infections. Many strains may become resistant to various antimicrobials, which can hinder the treatment of bacterial diseases. Organic farming seeks to avoid the selection and frequency of antimicrobial-resistant bacteria. This study aims to verify the resistance of EPEC and STEC from organic and conventional (industrial) broiler isolates to antimicrobials. All isolates were submitted to disk diffusion test with tetracycline, gentamicin, enrofloxacin, ceftriaxone and amoxicillin + clavulanate (TET, GEN, ENO, CTX, AMC) and PCR to detect specific virulence genes for EPEC and STEC. A total of 297 E. coli strains were isolated, 213 from conventional. In organic broiler, 84 strains were isolated. The strains from the conventional broiler isolates were resistant to five antimicrobials tested: TET 48.82% (104/213), ENO 28.17% (60/213), CTX 15.49% (33/213), GEN 14.55% (31/213), and AMC 7.04% (15/213), and 9.86% (21/213) were considered multidrug-resistant. Organic chicken strains were resistant to four of the antimicrobials tested: TET 35.7% (30/84), ENO 9.5% (8/84), CTX 2.4% (2/84), GEN 4.8% (4/84). Of the strains from the organic broiler chicken isolates, only 1.2% (1/84) was considered multidrug-resistant. No EPEC and STEC were found in the organic chicken samples. The multidrug resistance was characterized in 9.52% (2/21) of the EPEC and 4.76% (1/21) of the STEC. The study demonstrated the absence of EPEC and STEC strains in organic broilers and carcasses and a lower frequency of multiresistant strains compared to conventional breeding.(AU)

Comparative Study on the Predominance of Lactobacillus spp. and Escherichia Coli in Healthy vs Colibacillosis Diseased Broilers

This study aims to identify relative proportions of beneficial and pathogenic bacteria in the gut of broilers and risk factors that may be contributing to the development of colibacillosis disease in broiler farms of District Kasur, Punjab, Pakistan. For this, 10 healthy and 10 colibacillosis affected broiler farms were surveyed for ileum and blood sample collection along with data regarding farm management, antibiotic use and hygiene practices. Lactobacillus and Escherichia coli number was estimated using Miles and Misra method and colibacillosis was confirmed by Congo red dye assay. Lactobacillus and E. coli were identified biochemically. For risk factors analysis chi-square analysis was performed to find any significant association between the health status of the farm and risk factors. Results showed during disease and healthy conditions Lactobacillus and Escherichia coli counts differ significantly (p<0.05). E. coli counts (106-108 to 107-109) increased (p<0.05) about three folds and Lactobacillus counts decrease (106-108 to 105-107) about four folds in disease conditions. Risk factor analysis showed colibacillosis disease was significantly associated (p<0.05) with non-vaccinated flocks, natural ventilation systems, rodent presence and the lack of outfit disinfection or change by workers when moving between different houses. It is concluded that E. coli and Lactobacillus work antagonistically to each other. However, further research is necessary to determine the exact mechanisms by which E. coli and Lactobacillus influence the development of colibacillosis. While Lactobacillus as probiotic may help with prevention, good hygiene and management practices are still crucial in preventing the spread of disease.(AU)

Urethral obstruction due to seminal vesiculitis in a sheep: case report / Obstrução uretral por vesiculite seminal em ovino: relato de caso

We report a case of urethral obstruction due to seminal vesiculitis in a Dorper sheep, with symptoms of anuria, rectal prolapse, orchitis/epididymitis, and uroperitoneum and biochemical tests indicating severe azotemia. The animal died due to advanced azotemia, and necropsy revealed kidneys with cortical and medullary necrosis, pyelonephritis of renal calyces, hydronephrosis, ruptured and necrotic bladder, and vesicular, bulbourethral, and ampoule accessory sex glands. There was prostate hyperplasia that revealed a large amount of pus in the cross section, which was also observed bilaterally in the epididymis and right testis. Morphotintorial and biochemical analyses of bacteria obtained from microbiological culture revealed Corynebacterium sp. and Escherichia coli. Infection, hyperplasia, and abscessation of accessory sex glands caused urethral compression, resulting in an obstructive condition, similar to urolithiasis, in addition to bacteremia. Hyperplastic seminal vesiculitis, although rare, must be included among the differential diagnoses of obstructive processes in the urinary tract of sheep.

Relata-se um caso de obstrução uretral decorrente de vesiculite seminal em carneiro da raça Dorper, com quadro de anúria, prolapso retal, orquite/epididimite e uroperitôneo, com exames bioquímicos indicativos de severa azotemia. Devido ao quadro avançado de azotemia, o animal faleceu e, na necropsia, foi observado:: rins com necrose de cortical e medular, pielonefrite dos cálices renais e hidronefrose, bexiga rompida e necrosada, assim como glândulas sexuais acessórias vesiculares, bulbouretrais e ampola. Havia hiperplasia de próstata que, ao corte transversal, revelou grande quantidade de pus, que também foi observado bilateralmente no epidídimo e no testículo direito. As análises morfotintoriais e bioquímicas das bactérias obtidas a partir do cultivo microbiológico foram compatíveis com Corynebacterium sp. e Escherichia coli. A infecção, a hiperplasia e a abscedação das glândulas sexuais acessória, causaram compressão uretral, levando a um quadro obstrutivo, semelhante à urolitíase, somado à bacteremia. A vesiculite seminal hiperplásica, apesar de rara, deve ser incluída entre os diagnósticos diferenciais dos processos obstrutivos do trato urinário de carneiros.

Autolyzed Saccharomyces cerevisae reduce microbiological carcass contamination in feedlot steers / Suplementação com Saccharomyces cerevisaeautolisada reduz contaminação microbiológica da carcaça de novilhos terminados em confinamento

The present work aims to verify whether the autolyzed Saccharomyces cerevisiae reduces total coliforms, Escherichia coli and Salmonella spp. from the hide, feces and carcass of feedlot-finished steers. Eighteen half-Angus steers were subjected to three treatments daily for 105 days: control (n=6), Lev 4 g (diet with 4 g yeast animal day-1, n=6) or Lev 7 g (diet with 7 g yeast animal day-1, n=6). On Days 29 and 90 after entrance into the feedlot, fecal samples, skin swabs, water and food were collected to identify and count E. coli and total coliforms and identify Salmonella spp. On the day of slaughter, carcasses were collected to identify and quantify E. coli, total coliforms, and mesophiles. There were reductions in E. coli and total coliforms in fecal samples (P=0.0001 and 0.001, respectively) and mesophilic aerobics in carcasses (P= 0.05) in the treated groups, and no Salmonella spp. was observed in any of the samples collected. It was concluded that supplementation reduced fecal excretion of and, consequently, carcass contamination by E. coli, mesophiles and total coliforms in confined animals and that this technique is a beneficial and residue-free sanitary measure to improve the microbiological quality of meat.

Este trabalho objetivou verificar se o prebiótico a base de parede celular de Saccharomyces cerevisiae reduz coliformes totais, Escherichia coli e Salmonella spp da pele, fezes e da carcaça de bovinos terminados em confinamento. Para tanto, 18 novilhos, ½ sangue Angus foram submetidos a três tratamentos diários durante 105 dias: controle (n=6), Lev 4g (dieta com 4 g de levedura por animal dia-1, n=6) ou Lev 7g ( dieta com 7 g de levedura por animal dia-1, n=6). Nos dias 29 e 90 após a entrada no confinamento, coletou-se amostras de fezes, swab de pele, água e alimento para contagem de Escherichia coli e coliformes totais e isolamento de Salmonella spp. No dia do abate, realizou-se coleta nas carcaças para identificação de Salmonella spp e quantificação de Escherichia coli, coliformes totais, mesófilos. Notou-se redução de Escherichia coli e coliformes totais nas amostras de fezes (P=0,0001 e 0,001 respectivamente) e de Escherichia coli, coliformes totais e aeróbios mesófilos na carcaça (P=0,06; 0,10 e 0,05 respectivamente) nos grupos tratados. Houve ausência de Salmonella spp. em todas as coletas realizadas. Concluiu-se que a suplementação reduziu a excreção fecal e consequentemente, a contaminação da carcaça pela Escherichia coli, mesófilos e coliformes totais dos animais confinados, sendo uma medida sanitária benéfica e livre de resíduos para melhorar a qualidade microbiológica da carne.

Effect of plasma and heat treatments on orange juice quality / Efeito de plasma e tratamento térmico na qualidade do suco de laranja

Heat treatment is used in the orange juice industry to neutralize the action of pathogenic microorganisms. However, it can reduce the nutritional value of the juice. Thus, our study assessed the cold plasma treatment as an alternative method against Escherichia coli and Candida albicans in 'Lima' orange juice. Both, plasma and heat treatments, reduced the amount of E. coli in the juice, inactivating 16.72 and 100%, respectively. Plasma did not inactivate C. albicans, but heat treatment inactivated 100%. Plasma and heat treatment increased Hue angle and luminosity (more yellowish juice). Plasma reduced vitamin C, carotenoids, and polyphenols content, while increased flavonoids. Heat treatment reduced the carotenoid content. However, neither heat nor plasma treatment altered the antioxidant activity. The plasma treatment reduced the intensity of color (chroma), the soluble solids content and the acidity ratio, total sugars, and the vitamin C content of juice compared to the heat-treated and control juices. Plasma-treated juice showed increased levels of yellow flavonoids, total phenolics and antioxidant activity until the 12th day of storage.

O tratamento térmico é utilizado na indústria de suco de laranja para neutralizar a ação de microrganismos patogênicos. No entanto, pode reduzir o valor nutricional do suco. Assim, o estudo avaliou o tratamento com plasma frio como método alternativo contra Escherichia coli e Candida albicans em suco de laranja 'Lima'. Ambos os tratamentos, plasma e calor, reduziram a quantidade de E. coli no suco, inativando 16.72 e 100%, respectivamente. O plasma não inativou C. albicans, mas o tratamento térmico inativou 100%. Plasma e tratamento térmico aumentaram o ângulo Hue e a luminosidade do suco (tom mais amarelo). O plasma reduziu o conteúdo de vitamina C, carotenóides e polifenóis, enquanto aumentou os flavonóides. O tratamento térmico reduziu o teor de carotenóides. No entanto, nem o calor nem o tratamento com plasma alteraram a atividade antioxidante. O tratamento com plasma reduziu a intensidade da cor (croma), o teor de sólidos solúveis e a razão de acidez, açúcares totais e o teor de vitamina C do suco em comparação com os sucos tratados termicamente e controle. O suco tratado com plasma apresentou maiores teores de flavonóides amarelos, fenólicos totais e atividade antioxidante até o 12º dia de armazenamento.

Avaliação microbiológica de sorvetes comercializados na cidade de Pouso Alegre - MG / Microbiological evaluation of ice cream sold in the city of Pouso Alegre - MG

O presente estudo teve como objetivo avaliar a qualidade microbiológica de sorvetes comercializados na cidade de Pouso Alegre ­ MG. Foram adquiridas 2 amostras de sorvete de 18 sorveterias em um intervalo de 30 dias totalizando 36 amostras. As amostras de sorvetes foram submetidas às análises para enumeração de coliformes totais, coliformes termotolerantes, Estafilococos coagulase positiva e Salmonella spp. As análises foram realizadas segundo os protocolos da American Public Health Association descrita no Compendium of methods for the microbiological examination of foods. Neste estudo não foram encontradas espécies de Salmonella spp. entretanto, houve amostras contaminadas por E. coli e Estafilococos coagulase positiva.13,89% das amostras analisadas estavam fora dos padrões estabelecidos. Verificou-se ainda a presença de coliformes totais em 77,78% e de Staphylococcus sp. em 36,11% e, embora a legislação vigente não mencione limites de contaminação para estes microrganismos, pode-se dizer que a matéria-prima estava contaminada, que as condições higiênicas, no processamento e armazenamento estavam inadequados para este produto. As amostras analisadas obtidas de sorveterias da região central foram as mais contaminadas, onde foi encontrada a presença de E. coli e Estafilococos coagulase positiva. A presença desses microrganismos sugere falhas em algum momento do processamento, armazenamento ou da venda destes produtos tornando-os inadequados, podendo não só causar uma deterioração mais rápida do sorvete, mas também colocando em risco a saúde do consumidor.(AU)

This study aimed to evaluate the microbiological quality of ice cream sold in the city of Pouso Alegre ­ MG. Two ice cream samples were acquired from 18 ice cream parlors in a 30-day interval, totaling 36 samples. The ice cream samples were subjected to analysis for enumeration of total coliforms, thermotolerant coliforms, coagulase positive Staphylococci and Salmonella spp. The analyzes were performed according to the protocols of the American Public Health Association described in the Compendium of Methods for the Microbiological Examination of Foods. In this study no species of Salmonella spp. were found, however, there were samples contaminated by E. coli and coagulase positive Staphylococci. 13.89% of the analyzed samples were outside the established standards. It was also verified the presence of total coliforms in 77.78% and Staphylococcus sp. in 36.11% and, although the current legislation does not mention contamination limits for these microorganisms, it can be said that the raw material was contaminated, that the hygiene, processing and storage conditions were inadequate for this product. The analyzed samples obtained from ice cream parlors in the central region were the most contaminated, where the presence of E. coli and coagulase positive Staphylococci was found. The presence of these microorganisms suggests failures at some point in the processing, storage or sale of these products, making them unsuitable and not only causing a faster deterioration of the ice cream, but also putting the consumer's health at risk.(AU)

Singeing to improve visual aspect and microbiological quality of pig carcasses / Chamuscamento para melhora do aspecto visual e a qualidade microbiológica de carcaças de suínos

The proper operating conditions of the singeing machine on pig slaughterhouses to achieve good carcass quality are little reported. Thus, this study aimed to evaluate the effect of an automatic singeing machine on the quality of pig carcasses for better control in pork production. A two-factor (pressure and time) completely randomized design was used. The carcasses were subjected to four treatments using gas pressures of 0.6 and 0.8 kgf.cm-2 for 3.7 and 4.2 seconds of exposure to the flame. The carcasses were analyzed as for visual appearance, counts of Enterobacteriaceae and Escherichia coli, and temperature. Gas consumption was also assessed during the process. Carcasses subjected to 0.6 kgf.cm-2 for 4.2 s had a better visual appearance. Both pressure and time reduced the counts of Enterobacteriaceae and E. coli. Regarding gas consumption, exposure to the flame for 4.2 s consumed three times more gas than exposure for 3.7 s. Among the treatments tested, singeing using a pressure of 0.6 kgf.cm-2 for 4.2 s was sufficient to reduce microbial counts and improve visual appearance. This singeing standardization serves as a reference for slaughterhouses to produce pork with a visual appearance of better acceptability by consumers.(AU)

As condições adequadas de operação do chamuscador para contribuir com o aspecto visual e qualidade microbiológica são pouco relatadas. O objetivo deste estudo foi avaliar o efeito do chamuscador automático na qualidade das carcaças, visando melhor controle na produção de carne suína. O delineamento experimental adotado foi inteiramente casualizado com dois fatores (pressão e tempo). As carcaças suínas foram submetidas a quatro tratamentos com 0,6 e 0,8 kgf.cm-2 de pressão de gás e 3,7 e 4,2 segundos de exposição à chama. As carcaças foram analisadas quanto ao aspecto visual, contagem de Enterobacteriaceae e Escherichia coli e temperatura. Além disso, o consumo de gás foi avaliado na operação. As carcaças submetidas a 0,6 kgf.cm-2 por 4,2 s apresentaram melhores resultados de aspecto visual. Em geral, tanto a pressão quanto o tempo reduziram a contagem de Enterobacteriaceae e E. coli. Quanto ao consumo de gás, o tempo de 4,2 s apresentou um gasto 3 vezes maior que o tempo de 3,7 s. Entre os tratamentos testados, o chamuscamento com pressão de 0,6 kgf.cm-2 e tempo de 4,2 s apresentou-se suficiente para redução das contagens microbiana e melhor aspecto visual. A padronização desta etapa de chamuscamento serve de referência para matadouros a fim de produzir carne suína com aspecto visual de melhor aceitabilidade pelo mercado consumidor.(AU)

Retrospective study of bacterial agents found in urine culture of dogs: antimicrobial sensitivity and resistance profile / Estudo retrospectivo de agentes bacterianos observados na urocultura de cães: perfil de sensibilidade e resistência antimicrobiana

Urinary tract infections are commonly diagnosed in dogs, accounting for 2 to 3% of cases in the clinical routine, as cystitis being the most reported condition. Dogs of all ages and breeds can be affected, and early diagnosis is an important tool for therapeutic success. Urine culture and antibiogram are gold-standard tests for the diagnosis of bacterial cystitis, allowing correct therapy and better recovery of the patient, since currently there is great resistance to antimicrobials used in the veterinary clinics. Thus, the aim of this study was to determine the main etiological agents isolated in dog urine cultures, as well as the resistance and sensitivity profile of the isolated agents in relation to antibiotics, in order to assist the clinician ́s choice of the most appropriate antimicrobial, aiming at the patient's therapeutic success. For this study, a retrospective study was performed of 49 samples of urine cultures of male and female dogs, collected between 2012 and 2021, which were positive for bacterial growth. From this analysis, it was observed that Escherichia coli, Enterococcus spp. and Staphylococcus spp. were the most isolated agents, presenting higher antimicrobial resistance to cephalexin, sulfadiazine plus trimethoprim, ampicillin, enrofloxacin and ciprofloxacin, respectively.(AU)

s infecções do trato urinário são comumente diagnosticadas em cães, representando de 2 a 3% dos casos na rotina clínica, sendo a cistite a afecção mais relatada. Cães de todas as idades e raças podem ser acometidos, sendo o diagnóstico precoce uma ferramenta importante para o sucesso terapêutico. A urocultura e o antibiograma são exames padrão-ouro para o diagnóstico das cistites bacterianas, permitindo a terapêutica correta e melhor recuperação do paciente, já que atualmente há grande resistência aos antimicrobianos empregados na rotina clínica veterinária. Desta forma, o objetivo deste estudo foi determinar os principais agentes etiológicos isolados nas uroculturas de cães, bem como o perfil de resistência e sensibilidade dos agentes isolados frente aos antibióticos, de modo a auxiliar o médico veterinário na eleição do antimicrobiano mais adequado, visando sucesso terapêutico do paciente. Para realização deste estudo foi feita uma análise retrospectiva de 49 uroculturas de cães machos e fêmeas, coletadas entre os anos de 2012 e 2021, as quais apresentaram crescimento bacteriano positivo. A partir desta análise foi observado que Escherichia coli, Enterococcus spp. e Staphylococcus spp. foram os agentes mais isolados nas uroculturas, apresentando maior resis-tência aos antimicrobianos cefalexina, sulfazotrim ampicilina, enrofloxacina e ciprofloxacina, respectivamente.(AU)

Singeing to improve visual aspect and microbiological quality of pig carcasses

ABSTRACT The proper operating conditions of the singeing machine on pig slaughterhouses to achieve good carcass quality are little reported. Thus, this study aimed to evaluate the effect of an automatic singeing machine on the quality of pig carcasses for better control in pork production. A two-factor (pressure and time) completely randomized design was used. The carcasses were subjected to four treatments using gas pressures of 0.6 and 0.8 kgf.cm-2 for 3.7 and 4.2 seconds of exposure to the flame. The carcasses were analyzed as for visual appearance, counts of Enterobacteriaceae and Escherichia coli, and temperature. Gas consumption was also assessed during the process. Carcasses subjected to 0.6 kgf.cm-2 for 4.2 s had a better visual appearance. Both pressure and time reduced the counts of Enterobacteriaceae and E. coli. Regarding gas consumption, exposure to the flame for 4.2 s consumed three times more gas than exposure for 3.7 s. Among the treatments tested, singeing using a pressure of 0.6 kgf.cm-2 for 4.2 s was sufficient to reduce microbial counts and improve visual appearance. This singeing standardization serves as a reference for slaughterhouses to produce pork with a visual appearance of better acceptability by consumers.

RESUMO As condições adequadas de operação do chamuscador para contribuir com o aspecto visual e qualidade microbiológica são pouco relatadas. O objetivo deste estudo foi avaliar o efeito do chamuscador automático na qualidade das carcaças, visando melhor controle na produção de carne suína. O delineamento experimental adotado foi inteiramente casualizado com dois fatores (pressão e tempo). As carcaças suínas foram submetidas a quatro tratamentos com 0,6 e 0,8 kgf.cm-2 de pressão de gás e 3,7 e 4,2 segundos de exposição à chama. As carcaças foram analisadas quanto ao aspecto visual, contagem de Enterobacteriaceae e Escherichia coli e temperatura. Além disso, o consumo de gás foi avaliado na operação. As carcaças submetidas a 0,6 kgf.cm-2 por 4,2 s apresentaram melhores resultados de aspecto visual. Em geral, tanto a pressão quanto o tempo reduziram a contagem de Enterobacteriaceae e E. coli. Quanto ao consumo de gás, o tempo de 4,2 s apresentou um gasto 3 vezes maior que o tempo de 3,7 s. Entre os tratamentos testados, o chamuscamento com pressão de 0,6 kgf.cm-2 e tempo de 4,2 s apresentou-se suficiente para redução das contagens microbiana e melhor aspecto visual. A padronização desta etapa de chamuscamento serve de referência para matadouros a fim de produzir carne suína com aspecto visual de melhor aceitabilidade pelo mercado consumidor.

Identification of Virulence-Associated Markers in Escherichia Coli Isolated from Captive Red-Browed Amazon Parrot (Amazona Rhodocorytha)

Due to the genetic similarity of pathogenic Escherichia coli isolated from birds and pathotypes of human origin, it is suggested that they have a common ancestor and may exchange virulence-associated genes. This study aimed to detect virulence-associated genes in E. coli strains isolated from the Red-browed Amazon parrot (Amazona rhodocorytha) kept at a conservation institute in Brazil. High genetic variability in virulence was observed, since 12 virulence profiles were found among 14 strains. The number of virulence-associated genes of single strains ranged from 5 to 22 out of 33 genes tested, and only one strain did not present any virulence genes. Regarding adhesion genes, most strains presented from two to five genes, and crlA (85.7%) and fimC (85.7%) were the most frequent. Frequencies were similar for invasion and iron acquisition genes. Variations among genes were observed for serum resistance and toxin-related genes. Some of the E. coli strains isolated from parrots presented virulence genes that are commonly associated with pathotypes of human origin, including newborn meningitis E. coli, uropathogenic E. coli, and sepsis-associated E. coli. It is noteworthy that some of these genes were present in the majority of the analyzed strains. Our results indicate that these strains detected in clinically healthy parrots can be potential reservoirs of several virulence-associated genes. These genes can be transmitted to other E. coli strains, including those that affect humans. These E. coli strains present a high pathogenic potential of virulence-associated genes in extraintestinal pathogenic E. coli strains.(AU)

Colistin resistance profiles and genotypes of Escherichia coli isolates from dogs and cats

Background: Nowadays, antibiotic resistance has become an important problem, posing a serious threat to both human and animal medicine. Colistin is one of the last-resort drugs for the treatment of particularly caused by multidrug resistant bacteria. The aim of this study was to investigate the resistance of Escherichia coli strains against colistin and the presence of colistin resistance genes (mcr1, mcr2 and mcr3) in them. Antibiotyping and genotyping of all strains was also aimed. Materials, Methods & Results: A total of 75 isolates of Escherichia coli from healthy animals (38 dogs and 37 cats) were screened for colistin resistance by cultivation in a screening agar and then microbroth dilution method was performed. Antibiotic susceptibilities of the isolates were determined by KBDDM. The presences of mcr1, mcr2 and mcr3 genes were investigated by PCR. The colistin resistant strains were genotyped by using RAPD-PCR, and antibiotyped based on resistance profiles. In the screening test, 1 strain in cats and 2 strains in dogs were colistin-resistant. However, 18.6% of strains (from 14 cats and 3 dogs) were found as colistin-resistant in the microdilution test. MDR status was 76.31% and 97.29% in dog and cat strains, respectively. The colistin-resistant strains showed 78-100% and 65-90% similarities with respect to their antibiotypes and genotypes, respectively. mcr1, mcr2 and mcr3 genes were not found in any of the strains. Discussion: There is an increase in infections brought on by Gram negative bacteria with various antibiotic resistances in addition to infections brought on by bacteria that are antibiotic-resistant. In order to cure illnesses caused by resistant bacteria, the repurposing of outdated antibiotics may be on the table. Colistin is a crucial antibiotic in veterinary medicine, according to a number of published perspectives, although it should only be administered with caution. However, the discovery of the plasmid-derived mcr1 gene and subsequent reports that this gene has propagated around the world. Escherichia coli strains isolated from companion animals have been found to carry the mcr1 (colistin resistance gene), and possible human-animal cross-contamination has been looked into. The findings demonstrated that mcr1-carrying E. coli might inhabit pets and spread between people and animals. The cat and dog strains used in this investigation had variable colistin resistance rates, which varied between trials. Although no isolates were found to be positive for the mcr1-3 genes in this study, it is believed that colistin resistance, which is determined phenotypically, should not be ignored in terms of spreading both in cat and dog populations as well as in terms of risk to human health, given the possibility that resistance could occur with other different mechanisms. Epidemiological research still uses in vitro antibacterial susceptibility patterns. Our antibiotyping method, which was based on an analysis of several antibiotic resistances, provided quantitative data. Commercial software was utilized to conduct the evaluation. There are no reports or publications that provide quantitative antibiotyping data for E. coli strains in the literature. A popular technique for genotyping different bacterial species is RAPD-PCR. By determining if certain specific genotypes are similar to those of other resistance strains, RAPD-PCR and other genotyping data can be compared with antibiotic resistance profiles to determine the specific risk of treatment resistance in infectious diseases. All organisms that were colistin resistant exhibited multiple antibiotic resistance, and these findings were also related to RAPD genotypes. The findings indicated that colistin-resistant E. coli bacteria could potentially represent a risk to human health and were thought to be transmitted from cats and dogs to humans and vice versa.

Inhibitory effect of different probiotic formulations on Salmonella Heidelberg, avian pathogenic Escherichia coli and Campylobacter jejuni

A wide variety of microorganism species have been used as probiotics to improve the intestinal microbial balance, control and prevent the colonization of pathogenic bacteria and promote growth in animal production. Based on the various beneficial factors of probiotic agents, this study aimed to evaluate the effectiveness of three different formulations of probiotics strains through the analysis of antagonistic capacity against common pathogens from chickens gastrointestinal tract. Three formulations composed by Bacillus, Lactobacillus, Saccharomyces, Enterococcus, Bifidobacterium and Pediococcus were tested in vitro by the method of probiotic culture spot in plates seeded with inocula of Escherichia coli, Salmonella Heidelberg and Campylobacter jejuni. The inhibition halos were measured and classified according to the degree of pathogenic bacteria inhibition. The formulation containing an association among Bacillus, Lactobacillus and Saccharomyces presented better results when compared to the other formulations.

Escherichia coli vacuolating factor, involved in avian cellulitis, induces actin contraction and binds to cytoskeleton proteins in fibroblasts

Avian pathogenic Escherichia coli (APEC) isolated from avian cellulitis lesions produces a toxin, named Escherichia coli vacuolating factor (ECVF), that causes cell vacuolization and induces inflammatory response in broiler chicken. Methods We investigated the intracellular activities of ECVF in avian fibroblasts using fluorescence staining, electron microscopy, MTT and LDH measurements. As ECVF act specifically in avian cells, we performed blotting assay followed by mass spectrometry to better understand its initial intracellular protein recognition. Results ECVF induced actin contraction, mitochondrial damage and membrane permeability alterations. Ultrastructural analysis showed intracellular alterations, as nuclear lobulation and the presence of degraded structures inside the vacuoles. Moreover, ECVF induced cell death in fibroblasts. ECVF-biotin associates to at least two proteins only in avian cell lysates: alpha-actinin 4 and vinculin, both involved in cytoskeleton structure. Conclusion These findings demonstrated that ECVF plays an important role in avian cellulitis, markedly in initial steps of infection. Taken together, the results place this toxin as a target for drug and/or vaccine development, instead of the use of large amounts antibiotics.(AU)

Escherichia coli vacuolating factor, involved in avian cellulitis, induces actin contraction and binds to cytoskeleton proteins in fibroblasts

Avian pathogenic Escherichia coli (APEC) isolated from avian cellulitis lesions produces a toxin, named Escherichia coli vacuolating factor (ECVF), that causes cell vacuolization and induces inflammatory response in broiler chicken. Methods We investigated the intracellular activities of ECVF in avian fibroblasts using fluorescence staining, electron microscopy, MTT and LDH measurements. As ECVF act specifically in avian cells, we performed blotting assay followed by mass spectrometry to better understand its initial intracellular protein recognition. Results ECVF induced actin contraction, mitochondrial damage and membrane permeability alterations. Ultrastructural analysis showed intracellular alterations, as nuclear lobulation and the presence of degraded structures inside the vacuoles. Moreover, ECVF induced cell death in fibroblasts. ECVF-biotin associates to at least two proteins only in avian cell lysates: alpha-actinin 4 and vinculin, both involved in cytoskeleton structure. Conclusion These findings demonstrated that ECVF plays an important role in avian cellulitis, markedly in initial steps of infection. Taken together, the results place this toxin as a target for drug and/or vaccine development, instead of the use of large amounts antibiotics.(AU)

Multidrug resistance in Shiga toxin-producing Escherichia coli (STEC) isolated from broiler chickens at slaughter / Resistência a múltiplos antimicrobianos em Escherichia coli shigatoxigênica (STEC) isoladas de frangos de corte ao abate

Broiler chickens and derived products are a key source of Shiga toxin-producing Escherichia coli (STEC) in humans. This pathotype is responsible for causing severe episodes of diarrhea, which can progress to systemic complications. A rapid and accurate diagnosis of the disease, and early treatment of the infection with antimicrobials, can prevent it worsening. However, multidrug-resistant strains have potentially negative implications for treatment success. In this context, the aim of the present study was to isolate and identify multidrug-resistant STEC strains from broiler chickens and carcasses. Of 171 E. coli strains, isolated by conventional microbiological techniques and submitted to Polymerase Chain Reaction (PCR), for detection of stx1 and stx2 genes, 21.05% (36/171) were STEC pathotype, and most of them (66.67% - 24/36) carried both stx1 and eae genes. The multidrug resistance pattern was observed in 75% (27/36) of STEC strains. The presence of STEC in broiler chickens and carcasses reinforces that these sources may act as reservoirs for this pathotype. Multidrug-resistant bacteria contaminating animal products represent a public health issue because of the possibility of spread of multidrug-resistant determinants in the food chain and a higher risk of failure in human treatment when antimicrobials are needed.(AU)

Frangos de corte e seus produtos são importantes componentes na cadeia de transmissão de Escherichia coli do patotipo Shigatoxigênico (STEC) para humanos. Este patotipo é responsável por causar episódios de diarréia severos, que podem evoluir para complicações sistêmicas. O diagnóstico rápido e preciso da doença, e o tratamento com antimicrobianos ainda no início da infecção, podem evitar seu agravamento. Porém, cepas resistentes a múltiplos antimicrobianos podem ter implicações potencialmente negativas em relação ao sucesso do tratamento. Neste contexto, este estudo teve como objetivo isolar e identificar cepas STEC resistentes a múltiplos antimicrobianos em frangos de corte e carcaças. Das 171 cepas de E. coli isoladas pelo método bacteriológico convencional, e submetidas à Reação em Cadeia da Polimerase (PCR), para detecção dos genes stx1 e stx2, 21.05% (36/171) pertenciam ao patotipo STEC, a maioria (66.67% - 24/36) portando o gene stx1 associado ao gene eae. O perfil de multirresistência foi observado em 75% (27/36) das cepas STEC. A presença de cepas STEC no material estudado reforça o fato de que frangos vivos e carcaças devem ser considerados como reservatórios deste patotipo. A presença de cepas resistentes a múltiplos antimicrobianos, contaminando produtos de origem animal, representa um risco à Saúde Pública pela possibilidade de disseminação de determinantes de multirresistência e maior risco de insucesso no tratamento de indivíduos infectados.(AU)

Influence of dry and wet beef maturation on the microbiological quality and safety / Influência da maturação a seco e a vácuo na qualidade e segurança microbiológica da carne

The most used methods for the maturation process are vacuum (wet-aged) and dry (dry-aged), which can influence the microbiological quality and safety of meat for consumption. In this study, we aimed to verify the differences in microbiological quality between beef (Longissimus dorsi) that was wet-aged and dry-aged for 30 days, by quantification of indicator microorganism groups and molecular identification of Salmonella, Listeria monocytogenes, and diarrheagenic Escherichia coli. This study verified that the meat matured by the dry-aged method showed significantly lower counts of total coliforms, aerobic mesophiles, psychrotrophs, and molds and yeasts as compared to wet-aged meat. While the Salmonella spp. was not isolated in any beef sample, L. monocytogenes and enteropathogenic E. coli (EPEC), and shiga toxin-producing E. coli (STEC) and enterohemorrhagic E. coli (EHEC) were isolated only from wet-aged beef. Thus, it was concluded that the superficial dehydration of the meat during dry-aged maturation, if carried out correctly and hygienically, confers higher microbiological quality and can reduce the occurrence of microbiological hazards.

A maturação da carne agrega características sensoriais desejáveis ao consumidor. Os métodos mais utilizados são a vácuo (wet-aged) e à seco (dry-aged), que podem influenciar na qualidade e segurança microbiológica da carne para o consumo. O objetivo desse estudo foi verificar as diferenças de qualidade microbiológica entre cortes de contra-filé (Longissimus dorsi) maturados a vácuo e a seco por 30 dias, através da quantificação de grupos de micro-organismos indicadores e identificação molecular de Samonella, Listeria monocytogenes e Escherichia coli diarreiogênica. A carne maturada a seco apresentou contagens significativamente menores de coliformes totais, aeróbios mesófilos, psicrotróficos e bolores e leveduras em relação à carne maturada a vácuo. Salmonella spp. não foi isolada de nenhuma das amostras de carne analisadas. L. monocytogenes e E. coli enteropatogênica (EPEC), E. coli produtora de toxina shiga (STEC) e E. coli enterohemorrágica (EHEC) foram identificadas somente das carnes maturadas a vácuo. A desidratação superficial das peças durante a maturação a seco, desde que realizada de forma correta e higiênica, pode conferir maior qualidade e menor risco microbiológico para o consumo.(AU)

Subinhibitory concentrations of silver nanoparticles and silver nitrate on the adaptative and cross-resistance to antibiotics on bovine mastitis pathogens / Concentrações subinibitórias de nanopartículas de prata e nitrato de prata na resistência adaptativa e cruzada com antibióticos em patógenos de mastite bovina

Biocides and/or antibiotics used in subinhibitory concentrations can promote the development of adaptive resistance or even cross-resistance in microorganisms. However, studies on these responses following silver treatments are scarce in the literature. Silver-based compounds, including silver nanoparticles (Ag-NPs), can be an alternative in the prevention and treatment of bovine mastitis. Thus, this research evaluated the effect of subinhibitory dosages of Ag-NPs and Ag+ ions from silver nitrate (AgNO3) on Staphylococcus aureus and Escherichia coli isolated from milk of cows with mastitis. Ag-NPs were synthesized by chemical reduction using AgNO3 and sodium citrate and the minimum inhibitory concentration (MIC) of Ag-NPs and Ag+ ions on the mastitis pathogens were determined. Isolates were exposed to subinhibitory concentrations of Ag-NPs or AgNO3 for 10 consecutive days to verify the development of adaptive resistance evaluated by changes in the MIC values. The development of cross-resistance with antibiotics was also studied, being verified by comparing the sensitivity profile of treated cells with non-treated cells. AgNO3 was more effective against all isolates. There was no change in the MIC values or in the antibiotic sensitivity profile for both bacteria following consecutive exposure to subinhibitory dosages of Ag-NPs or AgNO3, indicating that silver was not able to select adaptive resistance or cross resistance to the tested antibiotics. The potential of silver presented by these results is favorable to the continuity of studies aiming to elaborate silver-based therapies for the treatment of bovine mastitis.

Biocidas e/ou antibióticos em concentrações sub-inibitórias podem promover o desenvolvimento de resistência adaptativa ou mesmo resistência cruzada nos micro-organismos. Entretanto, estudos destas respostas após o tratamento com a prata são escassos na literatura. Compostos a base de prata, incluindo as nanopartículas de prata (Ag-NPs), podem ser uma alternativa na prevenção e/ou tratamento de mastite bovina. Assim, este trabalho objetivou determinar o efeito de doses sub-inibitórias de Ag-NPs e dos íons Ag+ provenientes do nitrato de prata (AgNO3) sobre isolados de Staphylococcus aureus e de Escherichia coli, provenientes de leite de vacas com mastite. As Ag-NPs foram sintetizadas por redução química utilizando AgNO3 e citrato de sódio e a Concentração Mínima Inibitória (CMI) das Ag-NPs e íons Ag+ nos patógenos da mastite foi determinada. Os isolados foram expostos a concentrações sub-inibitórias de Ag-NPs ou de AgNO3 por 10 dias consecutivos para verificar o desenvolvimento de resistência adaptativa à prata pela mudança no valor da CMI, e de resistência cruzada com antibióticos pela mudança no perfil de sensibilidade em relação ao controle. AgNO3 apresentou-se mais efetivo contra todos os isolados. Não foi verificada alteração no valor da CMI nem do perfil de sensibilidade aos antibióticos, indicando que não houve seleção de resistência adaptativa à prata e de resistência cruzada aos antibióticos pelos micro-organismos estudados. O uso potencial da prata apresentado nos resultados é favorável à continuidade dos estudos objetivando a elaboração de terapias à base de prata para o tratamento da mastite bovina.

Influence of dry and wet beef maturation on the microbiological quality and safety / Influência da maturação a seco e a vácuo na qualidade e segurança microbiológica da carne

The most used methods for the maturation process are vacuum (wet-aged) and dry (dry-aged), which can influence the microbiological quality and safety of meat for consumption. In this study, we aimed to verify the differences in microbiological quality between beef (Longissimus dorsi) that was wet-aged and dry-aged for 30 days, by quantification of indicator microorganism groups and molecular identification of Salmonella, Listeria monocytogenes, and diarrheagenic Escherichia coli. This study verified that the meat matured by the dry-aged method showed significantly lower counts of total coliforms, aerobic mesophiles, psychrotrophs, and molds and yeasts as compared to wet-aged meat. While the Salmonella spp. was not isolated in any beef sample, L. monocytogenes and enteropathogenic E. coli (EPEC), and shiga toxin-producing E. coli (STEC) and enterohemorrhagic E. coli (EHEC) were isolated only from wet-aged beef. Thus, it was concluded that the superficial dehydration of the meat during dry-aged maturation, if carried out correctly and hygienically, confers higher microbiological quality and can reduce the occurrence of microbiological hazards.

A maturação da carne agrega características sensoriais desejáveis ao consumidor. Os métodos mais utilizados são a vácuo (wet-aged) e à seco (dry-aged), que podem influenciar na qualidade e segurança microbiológica da carne para o consumo. O objetivo desse estudo foi verificar as diferenças de qualidade microbiológica entre cortes de contra-filé (Longissimus dorsi) maturados a vácuo e a seco por 30 dias, através da quantificação de grupos de micro-organismos indicadores e identificação molecular de Samonella, Listeria monocytogenes e Escherichia coli diarreiogênica. A carne maturada a seco apresentou contagens significativamente menores de coliformes totais, aeróbios mesófilos, psicrotróficos e bolores e leveduras em relação à carne maturada a vácuo. Salmonella spp. não foi isolada de nenhuma das amostras de carne analisadas. L. monocytogenes e E. coli enteropatogênica (EPEC), E. coli produtora de toxina shiga (STEC) e E. coli enterohemorrágica (EHEC) foram identificadas somente das carnes maturadas a vácuo. A desidratação superficial das peças durante a maturação a seco, desde que realizada de forma correta e higiênica, pode conferir maior qualidade e menor risco microbiológico para o consumo.

Subinhibitory concentrations of silver nanoparticles and silver nitrate on the adaptative and cross-resistance to antibiotics on bovine mastitis pathogens / Concentrações subinibitórias de nanopartículas de prata e nitrato de prata na resistência adaptativa e cruzada com antibióticos em patógenos de mastite bovina

ABSTRACT: Biocides and/or antibiotics used in subinhibitory concentrations can promote the development of adaptive resistance or even cross-resistance in microorganisms. However, studies on these responses following silver treatments are scarce in the literature. Silver-based compounds, including silver nanoparticles (Ag-NPs), can be an alternative in the prevention and treatment of bovine mastitis. Thus, this research evaluated the effect of subinhibitory dosages of Ag-NPs and Ag+ ions from silver nitrate (AgNO3) on Staphylococcus aureus and Escherichia coli isolated from milk of cows with mastitis. Ag-NPs were synthesized by chemical reduction using AgNO3 and sodium citrate and the minimum inhibitory concentration (MIC) of Ag-NPs and Ag+ ions on the mastitis pathogens were determined. Isolates were exposed to subinhibitory concentrations of Ag-NPs or AgNO3 for 10 consecutive days to verify the development of adaptive resistance evaluated by changes in the MIC values. The development of cross-resistance with antibiotics was also studied, being verified by comparing the sensitivity profile of treated cells with non-treated cells. AgNO3 was more effective against all isolates. There was no change in the MIC values or in the antibiotic sensitivity profile for both bacteria following consecutive exposure to subinhibitory dosages of Ag-NPs or AgNO3, indicating that silver was not able to select adaptive resistance or cross resistance to the tested antibiotics. The potential of silver presented by these results is favorable to the continuity of studies aiming to elaborate silver-based therapies for the treatment of bovine mastitis.

RESUMO: Biocidas e/ou antibióticos em concentrações sub-inibitórias podem promover o desenvolvimento de resistência adaptativa ou mesmo resistência cruzada nos micro-organismos. Entretanto, estudos destas respostas após o tratamento com a prata são escassos na literatura. Compostos a base de prata, incluindo as nanopartículas de prata (Ag-NPs), podem ser uma alternativa na prevenção e/ou tratamento de mastite bovina. Assim, este trabalho objetivou determinar o efeito de doses sub-inibitórias de Ag-NPs e dos íons Ag+ provenientes do nitrato de prata (AgNO3) sobre isolados de Staphylococcus aureus e de Escherichia coli, provenientes de leite de vacas com mastite. As Ag-NPs foram sintetizadas por redução química utilizando AgNO3 e citrato de sódio e a Concentração Mínima Inibitória (CMI) das Ag-NPs e íons Ag+ nos patógenos da mastite foi determinada. Os isolados foram expostos a concentrações sub-inibitórias de Ag-NPs ou de AgNO3 por 10 dias consecutivos para verificar o desenvolvimento de resistência adaptativa à prata pela mudança no valor da CMI, e de resistência cruzada com antibióticos pela mudança no perfil de sensibilidade em relação ao controle. AgNO3 apresentou-se mais efetivo contra todos os isolados. Não foi verificada alteração no valor da CMI nem do perfil de sensibilidade aos antibióticos, indicando que não houve seleção de resistência adaptativa à prata e de resistência cruzada aos antibióticos pelos micro-organismos estudados. O uso potencial da prata apresentado nos resultados é favorável à continuidade dos estudos objetivando a elaboração de terapias à base de prata para o tratamento da mastite bovina.

Subinhibitory concentrations of silver nanoparticles and silver nitrate on the adaptative and cross-resistance to antibiotics on bovine mastitis pathogens / Concentrações subinibitórias de nanopartículas de prata e nitrato de prata na resistência adaptativa e cruzada com antibióticos em patógenos de mastite bovina

Biocides and/or antibiotics used in subinhibitory concentrations can promote the development of adaptive resistance or even cross-resistance in microorganisms. However, studies on these responses following silver treatments are scarce in the literature. Silver-based compounds, including silver nanoparticles (Ag-NPs), can be an alternative in the prevention and treatment of bovine mastitis. Thus, this research evaluated the effect of subinhibitory dosages of Ag-NPs and Ag+ ions from silver nitrate (AgNO3) on Staphylococcus aureus and Escherichia coli isolated from milk of cows with mastitis. Ag-NPs were synthesized by chemical reduction using AgNO3 and sodium citrate and the minimum inhibitory concentration (MIC) of Ag-NPs and Ag+ ions on the mastitis pathogens were determined. Isolates were exposed to subinhibitory concentrations of Ag-NPs or AgNO3 for 10 consecutive days to verify the development of adaptive resistance evaluated by changes in the MIC values. The development of cross-resistance with antibiotics was also studied, being verified by comparing the sensitivity profile of treated cells with non-treated cells. AgNO3 was more effective against all isolates. There was no change in the MIC values or in the antibiotic sensitivity profile for both bacteria following consecutive exposure to subinhibitory dosages of Ag-NPs or AgNO3, indicating that silver was not able to select adaptive resistance or cross resistance to the tested antibiotics. The potential of silver presented by these results is favorable to the continuity of studies aiming to elaborate silver-based therapies for the treatment of bovine mastitis.(AU)

Biocidas e/ou antibióticos em concentrações sub-inibitórias podem promover o desenvolvimento de resistência adaptativa ou mesmo resistência cruzada nos micro-organismos. Entretanto, estudos destas respostas após o tratamento com a prata são escassos na literatura. Compostos a base de prata, incluindo as nanopartículas de prata (Ag-NPs), podem ser uma alternativa na prevenção e/ou tratamento de mastite bovina. Assim, este trabalho objetivou determinar o efeito de doses sub-inibitórias de Ag-NPs e dos íons Ag+ provenientes do nitrato de prata (AgNO3) sobre isolados de Staphylococcus aureus e de Escherichia coli, provenientes de leite de vacas com mastite. As Ag-NPs foram sintetizadas por redução química utilizando AgNO3 e citrato de sódio e a Concentração Mínima Inibitória (CMI) das Ag-NPs e íons Ag+ nos patógenos da mastite foi determinada. Os isolados foram expostos a concentrações sub-inibitórias de Ag-NPs ou de AgNO3 por 10 dias consecutivos para verificar o desenvolvimento de resistência adaptativa à prata pela mudança no valor da CMI, e de resistência cruzada com antibióticos pela mudança no perfil de sensibilidade em relação ao controle. AgNO3 apresentou-se mais efetivo contra todos os isolados. Não foi verificada alteração no valor da CMI nem do perfil de sensibilidade aos antibióticos, indicando que não houve seleção de resistência adaptativa à prata e de resistência cruzada aos antibióticos pelos micro-organismos estudados. O uso potencial da prata apresentado nos resultados é favorável à continuidade dos estudos objetivando a elaboração de terapias à base de prata para o tratamento da mastite bovina.(AU)