High-risk clones of carbapenem resistant Klebsiella pneumoniae recovered from pediatric patients in Southern Brazil.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) exhibit high mortality rates in pediatric patients and usually belong to international high-risk clones. This study aimed to investigate the molecular epidemiology and carbapenem resistance mechanisms of K. pneumoniae isolates recovered from pediatric patients, and correlate them with phenotypical data. Twenty-five CRKP isolates were identified, and antimicrobial susceptibility was assessed using broth microdilution. Carbapenemase production and ß-lactamase genes were detected by phenotypic and genotypic tests. Multilocus sequence typing was performed to differentiate the strains and whole-genome sequencing was assessed to characterize a new sequence type. Admission to the intensive care unit and the use of catheters were significantly positive correlates of CRKP infection, and the mortality rate was 36%. Almost all isolates showed multidrug-resistant phenotype, and most frequent resistant gene was blaKPC. We observed the dissemination of ST307 and clones belonging to CG258, which are considered high risk. In pediatric patients, these clones present with high genomic plasticity, favoring adaptation of the KPC and NDM enzymes to healthcare environments.

Outbreak of vancomycin-resistant Enterococcus faecium ST1133 in paediatric patients with acute lymphoblastic leukaemia from southern Brazil.

OBJECTIVES: We aimed to investigate an outbreak of vancomycin-resistant Enterococcus faecium (VREfm) in paediatric patients from Hospital Pequeno Príncipe. The susceptibility profile was determined, and whole-genome sequencing (WGS) was used to analyse the genetic context of the strains. METHODS: Five VREfm isolates were recovered from sterile sites and surveillance cultures of two paediatric patients with acute lymphoblastic leukaemia. Species identification was performed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the minimum inhibitory concentration (MIC) was assessed according to the European Committee for Antimicrobial Susceptibility Testing (EUCAST). WGS was performed to analyse the genetic context of virulence and resistance genes, and in silico multilocus sequence typing was performed to identify the sequence typing of the strains. RESULTS: High-level vancomycin resistance was observed in all isolates (≥256 mg/L). WGS revealed the presence of mobile genetic elements, such as plasmids (rep2, rep11a, repUS15, rep17, and rep18a), insertion sequences, and phages. Multiple resistance genes (aac(6')-aph(2"), dfrG, ermB, and vanA) and virulence genes (acm and efaAfm) were identified. All the isolates were assigned to ST117 (ST1133 - via a novel MLST), an important epidemic lineage associated with nosocomial infections and outbreaks. CONCLUSION: Our results show that the ST117 (ST1133) VREfm isolates are circulating in paediatric patients, which raises a great concern. The development of new drugs as well as the implementation of an antimicrobial stewardship program are necessary for their correct management, limiting the spread of resistance in oncohematological patients.

Analysis of Clostridioides difficile Infection in Children with Diarrhea in Two Hospitals in Southern Brazil.

Clostridioides difficile infection (CDI) has been increasingly observed in children, but there is a lack of epidemiological and molecular data on CDI in Latin America. This prospective cohort study aimed to investigate the role of CDI in children with diarrhea. It included 105 children with antimicrobial-associated diarrhea (AAD) and analyzed the molecular characteristics of strains isolated from two hospitals in southern Brazil between 2017 and 2020. Fecal samples from the participants were tested for glutamate dehydrogenase (GDH) and A/B toxins using a rapid enzyme immunoassay. GDH-positive samples underwent automated real-time polymerase chain reaction and toxigenic culture. Toxigenic C. difficile isolates were selected for whole genome sequencing. Out of the 105 patients, 14 (13.3%) met the criteria for CDI. Children with a history of previous CDI and the presence of mucus in their stool were more likely to have CDI. Metronidazole was the most used treatment (71.4%), and three patients (23.1%) experienced CDI recurrence (rCDI). Although the number of sequenced isolates was limited, a wide diversity of sequence types (ST) was observed. In addition to toxin genes (tcdA, tcdB, cdtA, and cdtB), the isolates also exhibited virulence factors involved in adhesion (cwp66, groEL, slpA, fbpA/fbp68) and immune evasion (rmlA, rmlB, rmlC, gnd, rfbA-1), along with multiple resistance factors (gyrA mutation, norA, ermB, dfrF, and vanG). These findings highlight the prevalence and recurrence of CDI among hospitalized children. Longitudinal studies are needed to better understand the characteristics of CDI-associated diarrhea and its impact on the healthcare system in this population.

In vitro selection of Neisseria gonorrhoeae unveils novel mutations associated with extended-spectrum cephalosporin resistance.

The emergence of Neisseria gonorrhoeae strains resistant to extended-spectrum cephalosporins (ESCs) is a worldwide concern because this class of antibiotics represents the last empirical treatment option for gonorrhea. The abusive use of antimicrobials may be an essential factor for the emergence of ESC resistance in N. gonorrhoeae. Cephalosporin resistance mechanisms have not been fully clarified. In this study, we mapped mutations in the genome of N. gonorrhoeae isolates after resistance induction with cefixime and explored related metabolic pathways. Six clinical isolates with different antimicrobial susceptibility profiles and genotypes and two gonococcal reference strains (WHO F and WHO Y) were induced with increasing concentrations of cefixime. Antimicrobial susceptibility testing was performed against six antimicrobial agents before and after induction. Clinical isolates were whole-genome sequenced before and after induction, whereas reference strains were sequenced after induction only. Cefixime resistance induction was completed after 138 subcultures. Several metabolic pathways were affected by resistance induction. Five isolates showed SNPs in PBP2. The isolates M111 and M128 (ST1407 with mosaic penA-34.001) acquired one and four novel missense mutations in PBP2, respectively. These isolates exhibited the highest minimum inhibitory concentration (MIC) for cefixime among all clinical isolates. Mutations in genes contributing to ESC resistance and in other genes were also observed. Interestingly, M107 and M110 (ST338) showed no mutations in key determinants of ESC resistance despite having a 127-fold increase in the MIC of cefixime. These findings point to the existence of different mechanisms of acquisition of ESC resistance induced by cefixime exposure. Furthermore, the results reinforce the importance of the gonococcal antimicrobial resistance surveillance program in Brazil, given the changes in treatment protocols made in 2017 and the nationwide prevalence of sequence types that can develop resistance to ESC.

Lower airway microbiota and decreasing lung function in young Brazilian cystic fibrosis patients with pulmonary Staphylococcus and Pseudomonas infection.

Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene that leads to respiratory complications and mortality. Studies have shown shifts in the respiratory microbiota during disease progression in individuals with CF. In addition, CF patients experience short cycles of acute intermittent aggravations of symptoms called pulmonary exacerbations, which may be characterized by a decrease in lung function and weight loss. The resident microbiota become imbalanced, promoting biofilm formation, and reducing the effectiveness of therapy. The aim of this study was to monitor patients aged 8-23 years with CF to evaluate their lower respiratory microbiota using 16S rRNA sequencing. The most predominant pathogens observed in microbiota, Staphylococcus (Staph) and Pseudomonas (Pseud) were correlated with clinical variables, and the in vitro capacity of biofilm formation for these pathogens was tested. A group of 34 patients was followed up for 84 days, and 306 sputum samples were collected and sequenced. Clustering of microbiota by predominant pathogen showed that children with more Staph had reduced forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) compared to children with Pseud. Furthermore, the patients' clinical condition was consistent with the results of pulmonary function. More patients with pulmonary exacerbation were observed in the Staph group than in the Pseud group, as confirmed by lower body mass index and pulmonary function. Additionally, prediction of bacterial functional profiles identified genes encoding key enzymes involved in virulence pathways in the Pseud group. Importantly, this study is the first Brazilian study to assess the lower respiratory microbiota in a significant group of young CF patients. In this sense, the data collected for this study on the microbiota of children in Brazil with CF provide a valuable contribution to the knowledge in the field.

Novel Insights into blaGES Mobilome Reveal Extensive Genetic Variation in Hospital Effluents.

Mobile genetic elements contribute to the emergence and spread of multidrug-resistant bacteria by enabling the horizontal transfer of acquired antibiotic resistance among different bacterial species and genera. This study characterizes the genetic backbone of blaGES in Aeromonas spp. and Klebsiella spp. isolated from untreated hospital effluents. Plasmids ranging in size from 9 to 244 kb, sequenced using Illumina and Nanopore platforms, revealed representatives of plasmid incompatibility groups IncP6, IncQ1, IncL/M1, IncFII, and IncFII-FIA. Different GES enzymes (GES-1, GES-7, and GES-16) were located in novel class 1 integrons in Aeromonas spp. and GES-5 in previously reported class 1 integrons in Klebsiella spp. Furthermore, in Klebsiella quasipneumoniae, blaGES-5 was found in tandem as a coding sequence that disrupted the 3' conserved segment (CS). In Klebsiella grimontii, blaGES-5 was observed in two different plasmids, and one of them carried multiple IncF replicons. Three Aeromonas caviae isolates presented blaGES-1, one Aeromonas veronii isolate presented blaGES-7, and another A. veronii isolate presented blaGES-16. Multilocus sequence typing (MLST) analysis revealed novel sequence types for Aeromonas and Klebsiella species. The current findings highlight the large genetic diversity of these species, emphasizing their great adaptability to the environment. The results also indicate a public health risk because these antimicrobial-resistant genes have the potential to reach wastewater treatment plants and larger water bodies. Considering that they are major interfaces between humans and the environment, they could spread throughout the community to clinical settings. IMPORTANCE In the "One Health" approach, which encompasses human, animal, and environmental health, emerging issues of antimicrobial resistance are associated with hospital effluents that contain clinically relevant antibiotic-resistant bacteria along with a wide range of antibiotic concentrations, and lack regulatory status for mandatory prior and effective treatment. blaGES genes have been reported in aquatic environments despite the low detection of these genes among clinical isolates within the studied hospitals. Carbapenemase enzymes, which are relatively unusual globally, such as GES type inserted into new integrons on plasmids, are worrisome. Notably, K. grimontii, a newly identified species, carried two plasmids with blaGES-5, and K. quasipneumoniae carried two copies of blaGES-5 at the same plasmid. These kinds of plasmids are primarily responsible for multidrug resistance among bacteria in both clinical and natural environments, and they harbor resistant genes against antibiotics of key importance in clinical therapy, possibly leading to a public health problem of large proportion.

Comparative genomics of a novel clade shed light on the evolution of the genus Erysipelothrix and characterise an emerging species.

Erysipelothrix sp. isolates obtained from a deadly outbreak in farmed turkeys were sequenced and compared to representatives of the genus. Phylogenetic trees-supported by digital DNA:DNA hybridization and Average Nucleotide Identity-revealed a novel monophyletic clade comprising isolates from pigs, turkeys, and fish, including isolates previously described as E. sp. Strain 2. Genes coding for the SpaC protein, typically found in E. sp. Strain 2, were detected in all isolates of the clade. Therefore, we confirm E. sp. Strain 2 represents a unique species that may be isolated from a broad host range, and the name "Erysipelothrix takahashiae" is suggested. Core genome analysis showed that the pathogenic species of this genus, E. rhusiopathiae and the clade E. sp. Strain 2, are enriched in core functionalities related to nutrient uptake and transport, but not necessarily homologous pathways. For instance, whereas the aerobic DctA transporter may uptake C4-dicarboxylates in both species, the anaerobic DcuC transporter is exclusive of the E. sp. Strain 2. Remarkably, the pan-genome analysis uncovered that genes related to transport and metabolism, recombination and repair, translation and transcription in the fish isolate, within the novel clade, have undergone a genomic reduction through pseudogenization. This reflects distinct selective pressures shaping the genome of species and strains within the genus Erysipelothrix while adapting to their respective niches.

Genome sequencing and analysis of plant growth-promoting attributes from Leclercia adecarboxylata.

Plant growth-promoting bacteria are ecological alternatives for fertilization, mainly for gramineous. Since plant x bacteria interaction is genotype and strain dependent, searching for new strains may contribute to the development of new biofertilizers. We aim to characterize plant growth-promoting capacity of Leclercia adecarboxylata strain Palotina, formerly isolated by our group in corn. A single isolated colony was taken and its genome was sequenced using Illumina technology. The whole genome was compared to other Leclercia adecarboxylata strains, and their biological and growth-promoting traits, such as P solubilization and auxin production, were tested. Following that, a 4.8 Mb genome of L. adecarboxylata strain Palotina was assembled and the functional annotation was carried out. This paper is the first to report the genes associated with plant growth promotion demonstrating in vitro indole acid production by this strain. These results project the endophyte as a potential biofertilizer for further commercial exploitation.

Effect of dietary inclusion of dried apple pomace on faecal butyrate concentration and modulation of gut microbiota in dogs.

This research aimed to evaluate the apparent total tract digestibility (ATTD) of nutrients, metabolisable energy (ME) and palatability of the diet, as well as products of intestinal fermentation and faecal microbiota of dogs fed with dried apple. For this purpose, three experiments were performed. In Experiment I, digestibility and ME of four diets containing 0%, 3%, 6% and 9% dried apple were evaluated, in addition to the faecal characteristics of the dogs. The diets were offered to eight adult dogs, distributed in double Latin square (4 × 4), totalling eight repetitions per treatment. In Experiment II, products of intestinal fermentation and faecal microbiota from 16 adult dogs fed diets containing 0% and 9% dried apple for 30 d (n = 8) were evaluated. Finally, Experiment III compared the dietary preference of 0 vs. 9% dried apple using 15 adult dogs. The inclusion of dried apple in the diet (p < 0.05) showed a linear reduction in the ATTD of dry matter (DM), crude protein (CP), and acid hydrolysed ether extract (EEA), and a linear increase in the ATTD of total dietary fibre (TDF). Consumption of 9% of dried apple increased faecal butyrate and reduced propionate and ammonia (p < 0.05). With this diet, there was also an increase (p < 0.05) in the faecal concentration of Faecalibacterium, Erysipelatoclostridium, Blautia, and Bacteroides. No differences were found in the palatability of the diets. The inclusion of up to 9% of dried apple in the diet reduces the digestibility of nutrients and does not influence the dogs' food preference; however, it improves some indicators of dogs' intestinal functionality.

Effects of aroA deleted E. coli vaccine on intestinal microbiota and mucosal immunity.

E. coli infection of broilers can result in systemic diseases and productivity losses. Use of antimicrobials against this condition is common but other approaches, such as vaccination, are gaining ground. Anecdotal field reports indicate that intestinal health is improved unspecifically following E. coli live vaccination. We hypothesized that the intestine may be an important site for the functionality of the vaccine. Vaccine effects on the intestine were assessed. Spray vaccination induced marked alterations of the caecum microbiota of broilers within 3 days, and this effect gradually waned. However, T cell activation occurred in the spleen, but not in caecal tonsils, and anti-E. coli IgA was concentrated in the respiratory mucosae. Accordingly, IL-6 mRNA was produced in the lungs following immunization. Overall, these data are an initial indication that any vaccine-induced effects on the intestine are greatly associated with the microbiota. However, immunity conferred by vaccination is not primarily induced in gut-associated lymphoid tissues.

Microbial communities network analysis of anaerobic reactors fed with bovine and swine slurry.

Anaerobic digestion can produce biogas as an eco-friendly energy source, driven by a microbial community-dependent process and, as such, suffer influences from many biotic and abiotic factors. Understanding the players and how they interact, the mechanisms involved, what the factors are, and how they influence the biogas process and production is an important way to better control it and make it more efficient. Metagenomic approach is a powerful tool to assess microbial diversity and further, allow correlating changes in microbial communities with multiple factors in virtually all environments. In the present study, we used metagenomic approach to assess microbial community structure changes in two biodigesters, differing in their biogas production capacity, architecture, and feed. A total of 1,440,096 reads of the 16S rRNA gene V4 region were obtained and analyzed. The main bacterial phyla were Firmicutes and Bacteroidetes in both biodigesters, but the biodiversity was greater in the Upflow Anaerobic Sludge Blanket (UASB) reactor fed with bovine manure than in the Continuous Stirred Tank Reactor (CSTR) fed with swine manure, which also correlated with an increase in biogas or methane production. Microbial community structure associated with biodigesters changed seasonally and depended on animal growth stage. Random forest algorithm analysis revealed key microbial taxa for each biodigester. Candidatus Cloacomonas, Methanospirillum, and Methanosphaera were the marker taxa for UASB and the archaea groups Methanobrevibacter and Candidatus Methanoplasma were the marker taxa for CSTR. A high abundance of Candidatus Methanoplasma and Marinimicrobia SAR406 clade suggested lower increments in methane production. Network analysis pointed to negative and positive associations and specific key groups, essential in maintaining the anaerobic digestion (AD) process, as being uncultured Parcubacteria bacteria, Candidatus Cloacomonas, and Candidatus Methanoplasma groups, whose functions in AD require investigation.

Cyclophosphamide Increases Lactobacillus in the Intestinal Microbiota in Chickens.

Recent data in humans indicate that immunosuppression is correlated with shifts in the intestinal microbiota. However, the relationship between immunosuppression and intestinal microbiota has not been studied in chickens. Thus, we investigated the correlations between immune cells and intestinal microbiota by massive parallel sequencing of the 16S rRNA bacterial gene in chickens immunosuppressed with cyclophosphamide. The results showed correlations between peripheral immune cells and intestinal microbiota. Surprisingly, an increase in the abundance of intestinal Lactobacillus in the immunosuppressed chickens was observed. These birds also had low intestinal IgA antibody levels among other alterations in the microbiota. These shifts indicate a role of the immunity system in controlling the microbiota of birds.IMPORTANCE Poultry production is a very intensive industry. Due to the substantial number of animals being raised by any one producer, even small variations in productivity lead to important economical outcomes. The intestinal microbiota of birds is under intense scrutiny by the immune system. Therefore, it is a factor that can influence the states of health and disease of the host. The body of knowledge on the interactions between these systems is gradually bringing practical guidance for poultry production.

Diversity of Sinorhizobium (Ensifer) meliloti Bacteriophages in the Rhizosphere of Medicago marina: Myoviruses, Filamentous and N4-Like Podovirus.

Using different Sinorhizobium meliloti strains as hosts, we isolated eight new virulent phages from the rhizosphere of the coastal legume Medicago marina. Half of the isolated phages showed a very narrow host range while the other half exhibited a wider host range within the strains tested. Electron microscopy studies showed that phages M_ort18, M_sf1.2, and M_sf3.33 belonged to the Myoviridae family with feature long, contractile tails and icosaedral head. Phages I_sf3.21 and I_sf3.10T appeared to have filamentous shape and produced turbid plaques, which is a characteristic of phages from the Inoviridae family. Phage P_ort11 is a member of the Podoviridae, with an icosahedral head and a short tail and was selected for further characterization and genome sequencing. P_ort11 contained linear, double-stranded DNA with a length of 75239 bp and 103 putative open reading frames. BLASTP analysis revealed strong similarities to Escherichia phage N4 and other N4-like phages. This is the first report of filamentous and N4-like phages that infect S. meliloti.

Draft Genome Sequence of Pediococcus acidilactici Strain LPBC161, Isolated from Mature Coffee Cherries during Natural Fermentation.

Here, we report the draft genome sequence of Pediococcus acidilactici strain LPBC161, a lactic acid bacterium isolated from mature coffee cherries in Brazil. The genome sequence of P. acidilactici LPBC161 provides valuable information on the mechanisms of adaptation and metabolism of lactic acid bacteria (LAB) in the environment and stressor factors of coffee processing.

Effect of an Enterococcus faecium probiotic on specific IgA following live Salmonella Enteritidis vaccination of layer chickens.

Probiotics and immunization are being widely adopted by the poultry industry with the goal of controlling Salmonella enterica. However, the interaction between these two management protocols has been sparsely studied. The present study aimed to understand the role of an Enterococcus faecium probiotic in the production of salmonella-specific IgA in layers immunized with a live vaccine. Four groups were used: "Control" (no vaccine or probiotic); "Probiotic" (which received an E. faecium product); "Vaccine" (immunized with two doses of a live attenuated S. Enteritidis vaccine); and "Vaccine + probiotic". Faecal salmonella-specific IgA was analysed 7 and 20 days post-vaccination (dpv) boost. At 7 dpv, the "Vaccine" and "Vaccine + probiotic" groups had similar IgA levels. However, at 20 dpv, IgA levels were two times higher in the "Vaccine + probiotic" group compared to the "Vaccine" group. To understand the role of the intestinal microbiota in this finding, bacterial diversity in faeces was analysed by 16S rRNA gene sequencing. The improvement in IgA production in probiotic-treated birds was accompanied by marked changes in the faecal microbiome. Some of the main differences between the "Vaccine" and "Vaccine + probiotic" groups included reduction of Escherichia-Shigella and increases in Blautia, Anaerotruncus and Lactobacillus in the latter group. Although no direct causal link can be established from this study design, it is possible that the E. faecium probiotic induces improved antibody production following vaccination via modulation of the intestinal microbiota.

Avaliação da resposta imunológica da mucosa intestinal de frangos de corte desafiados com diferentes sorovares de Salmonella / Evaluation of immune response of the intestinal mucosa in broilers challenged with different Salmonella serovars

Objetivou-se com o presente estudo comparar o efeito de diferentes sorovares de Salmonella na resposta imune local da mucosa do intestino de frangos de corte. Aos sete dias de idade, as aves foram desafiadas com os sorovares S. Enteritidis, S. Typhimurium, S. Senftenberg, S. Mbandaka e S. Minnesota. Foi observado que todos os sorovares testados foram capazes de colonizar o intestino das aves sendo possível o isolamento de Salmonella em suabes de cloaca, 48 h após inoculação. De maneira geral, as aves do grupo controle negativo, que não foram desafiados apresentaram quantidade significativamente menor de células imunológicas na mucosa intestinal do que as aves desafiadas. Porém, verificou-se que os sorovares de Salmonella, utilizados neste estudo, apresentaram diferentes efeitos sobre a dinâmica celular da mucosa do íleo e ceco e afetaram de modo diferente o ganho de peso e ganho médio diário das aves demonstrando distintos graus de patogenicidade. Os sorovares Enteritidis e Typhimurium apresentaram um efeito mais intenso tanto no desempenho quanto na mobilização de células imunológicas na mucosa intestinal de frangos de corte.

The study was designed to compare the effect of different Salmonella serovars in immune response across the count of CD8+ cells, CD4+ cells, goblet cells and macrophages in the gut mucosa of broilers. During the experimental inoculation at 7 day-old were used Salmonella enterica subspecies enterica sorovars Enteritidis, Typhimurium, Senftenberg, Mbandaka and Minnesota. It was observed that all serovars tested were capable of contaminating the poultry being possible counts of Salmonella in cloacal swabs, 48 h after inoculation and into the crop and cecum, at 14 and 20 day-old. Serovars tested had different effects on broiler performance assessed at 20 days. In the mucosa of the ileum and cecum of broilers, it was observed that some of the serotypes increased CD8 + cells, CD4 + cells, goblet cells and macrophages compared to the negative control group both at 14 and at 20 day-old. S. Enteritidis and S. Typhimurium are the serovars that showed the more intense effect in live performance and in the immune system of birds showing pathogenic characteristic; generally the broilers of the negative control showed significantly less immune cells on the intestinal mucosa than broilers inoculated experimentally. However, it was found that the Salmonella serovars used in this study had different effects on the cellular dynamics of the mucosa of the ileum and cecum and differently affect weight gain and average daily gain of poultry showing different levels of pathogenicity.

Modelo de protocolo experimental para induzir, classificar e avaliar as enterites inespecíficas em frangos de corte / Experimental protocol model to induce, classified and evaluate non specific enteritis in broilers

Vários fatores negativos podem afetar a saúde intestinal de frangos de corte e reduzir o seu desempenho. Aditivos para alimentação animal, chamados melhoradores de crescimento são utilizados na produção de frangos para controlar os problemas intestinais. Entretanto, a dificuldade de se induzir enterites em condições experimentais torna difícil a avaliação destes produtos. O objetivo deste estudo foi avaliar o melhor modelo experimental para induzir enterite em frangos de corte. Foram utilizados 192 pintinhos de corte, machos (Cobb 500®), divididos em esquema fatorial 2x4 (com boa ou baixa qualidade do óleo na dieta e com ou sem vacina contra coccidiose e doença de Gumboro), com oito tratamentos. As aves foram alojadas em cama de maravalha, com água e ração à vontade, e foram pesadas semanalmente. Nos dias 14, 21, 28 e 35, seis aves por tratamento foram abatidas para avaliação de lesões macroscópicas e microscópicas mediante a implementação de um sistema padrão de classificação de severidade das lesões que considerou infiltração linfocítica, morfologia dos enterócitos, edema intersticial e dilatação dos vasos linfáticos na mucosa do intestino. Foi observado que frangos alimentados com gordura de baixa qualidade na ração apresentaram menor ganho de peso e maior severidade de lesões histológicas em todos os segmentos intestinais. Estas lesões foram mais severas em aves desafiadas com coccidiose e doença de Gumboro. Estes resultados sugerem que a inclusão de gordura de baixa qualidade na ração, associada ao desafio com cocciciose no primeiro dia de vida e contra doença de Gumboro no 16º dia, é o melhor protocolo para induzir enterite em frangos de corte em condições experimentais, e ainda que o sistema padrão de classificação de severidade de lesões intestinais foi adequado para avaliar as enterites em frangos de corte.

Several negative conditions affect broilers intestinal health and reduce their performance. Feed additives, called growth promoters, are used in broilers production to control enteric problems, but is very difficult to evaluate these products in experimental conditions. The aim of this study was to evaluate the best experimental model to induce enteritis in broilers. A 192 one-day-old male broilers (Cobb 500®) were divided into 2x4 a factorial design (with good or poor quality oil in diet and with or without coccidiosis and Gumboro disease vaccine), with eight treatments. The birds were housed on litter, with water and feed ad libitum and were weighed weekly. At days 14, 21, 28 and 35, six birds per treatment were euthanized and gut gross lesions evaluated. Samples of duodenum, jejunum and ileum were taken for histopathological evaluation. A standard lesion score considering lymphocytic infiltration, enterocytes morphology, interstitial edema, and lymph vessel dilation was used. It was observed that broilers fed with poor quality of oil in the diet showed lower body weight and more severe macroscopic and histopathologic lesions on all intestinal segments. These lesions were more severe in birds challenged with coccidiosis and Gumboro disease. The results suggest that an inclusion of poor quality of oil in diet, associated with challenge with coccidiosis at first day and Gumboro virus vaccine at 16 day is the best protocol to promote enteritis in broilers at experimental conditions, and that use of standard lesion score was useful to evaluate enteritis.

Presence of Salmonella spp. in reused broiler litter / Presencia de Salmonella spp. en cama reutilizada de pollos de engorde / Presença de Salmonella spp. em cama reutilizada de frangos de corte

Background: reutilization of poultry litter for multiple broiler flocks is a common practice in modern production systems due to the increasing scarcity and cost of bedding materials, and the necessity to reduce environmental impact. However, this practice has been associated with sanitary risks, such as the presence of Salmonella spp. in broiler meat. Objective: a study was conducted to detect the presence of Salmonella spp. in reused litters. Methods: 1,280 litter samples from Midwestern Brazilian poultry farms were analyzed during seven consecutive flocks. Samples were collected from flocks aged 28 to 32 days. Disposable shoe covers were used for sample collections. Presence of Salmonella spp. was determined by microbiological isolation. During the interval period between flocks the litter was fermented prior to its reuse by covering it with a black plastic canvas for 7 days. Results: positive samples for Salmonella spp. decreased when the number of litter reuses increased compared with the first reuse of the litter. An anaerobic digestion process with biological and physicochemical changes in the litter material and microbial communities may explain the low survival of pathogenic bacteria such as Salmonella spp. Conclusions: our study demonstrates that litter reused after the fermentation process is a safe and recommended practice to reduce the presence of Salmonella spp.

Antecedentes: la reutilización de la cama de pollos de engorde es una práctica común en el sistema moderno de producción avícola, sustentada por la reducción en el impacto ambiental, escasez de este material y disminución de costos de producción. Sin embargo, esta reutilización se ha asociado con riesgos sanitarios, tales como presencia de Salmonella spp. en los lotes de pollo. Objetivo: se realizó un estudio con el fin de detectar la presencia de Salmonella spp. en camas reutilizadas y fermentadas de pollos de engorde pertenecientes a granjas comerciales. Métodos: se analizaron 1280 muestras de cama de diversas granjas avícolas ubicadas en el centro oeste de Brasil durante siete lotes consecutivos de pollos. Las muestras de cama fueron tomadas de galpones con aves entre los 28 y 32 días de edad, utilizando polainas. La presencia de Salmonella spp. se determinó mediante aislamiento microbiológico. Durante el intervalo entre lotes, la cama fue fermentada antes de cada reutilización cubriendo la superficie entera de la cama con una lona de plástico negra por siete días. Resultados: fue observada una disminución en las muestras positivas para Salmonella con la reutilización y fermentación de las camas entre lotes, significativa con respecto al primer reuso. Esto indica que puede estar ocurriendo un proceso de digestión anaeróbica que conduce a que los procesos biológicos y físico-químicos entre el material de la cama y la comunidad microbiana allí presentes, estén afectando la supervivencia de bacterias patógenas como Salmonella. Conclusiones: nuestro estudio demuestra que la reutilización de la cama es una práctica segura y recomendable cuando se realiza después del proceso de fermentación, debido a que reduce la presencia de Salmonella spp.

Antecedentes: a reutilização de cama aviária por vários lotes é uma prática moderna do sistema de produção de aves, baseada na redução do impacto ambiental, escassez de este material e diminuição nos custos de produção. Porém, dita prática é associada com riscos sanitários como a presença de patógenos como Salmonella spp. nos lotes de frango. Objetivo: uma pesquisa foi realizada para detectar a presença de Salmonella spp. na cama reutilizada e fermentada de produtores de frango. Métodos: foram analisadas 1280 amostras de cama de diferentes produtores do Centro-oeste do Brasil durante sete lotes consecutivos. As amostras de cama foram coletadas com aves na idade entre 28 e 32 dias usando pró-pés descartáveis e a presença de Salmonella spp. foi determinada por isolamento bacteriológico. Durante o intervalo dos lotes a cama foi tratada antes da reutilização por meio da cobertura através de uma lona plástica preta em toda a superfície interna do aviário por sete dias. Resultados: foi observada uma diminuição no número de amostras positivas de Salmonella spp. com a reutilização e fermentação das camas entre os lotes, significativa em relação ao primeiro reuso. Isto indica que o processo de reutilização, seguido de fermentação anaeróbia do material da cama pela comunidade de microrganismos afetou a sobrevivência de bactérias patogênicas como Salmonella spp. Conclusões: este estudo evidencia que o reuso da cama é seguro e recomendado quando realizado após o processo de fermentação no intervalo do lote, devido a que diminui a presença de Salmonella spp.