Proteus mirabilis is an opportunistic pathogen often associated with a variety of human infections acquired both in the community and in hospitals. In this context, the present work aimed to evaluate the genotypic and phenotypic characteristics of the virulence factors and antimicrobial resistance determinants of 32 P. mirabilis strains isolated from chicken carcasses in a poultry slaughterhouse in the north of the state of Paraná, Brazil, in order to assess a potential zoonotic risk. The isolates presented a variety of virulence genes that contribute to the development of infection in humans. The mrpA, pmfA, atfA (fimbriae), ireA (siderophores receptor), zapA, ptA (Proteases), and hpmA (hemolysin) genes were found in 32 (100%) isolates and ucaA (fimbriae) in 16 (50%). All isolates showed aggregative adherence in HEp-2 cells and formed biofilms. Of all strains, 27 (84.38%) showed cytotoxic effects in Vero cells. Antimicrobial susceptibility was tested using 20 antimicrobials, in which 25 (78.13%) strains were considered multidrug-resistant. The presence of bla ESBL and bla ampC genes conferring resistance to β-lactams and qnr to quinolones were also detected in the isolates after presumption in the phenotypic test, in which 7 (21.88%) isolates contained the CTX-M-2 group, 11 (34.38%) contained CIT group and 19 (59.38%) contained qnrD. Therefore, chicken carcasses contaminated with P. mirabilis may pose a health risk to the consumer, as these isolates have a variety of virulence and antimicrobial resistance characteristics that can be found in P. mirabilis strains isolated from human infections.

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Given the need to understand the virulence profile of Proteus mirabilis isolates from cellulitis in broiler chickens and their ability to cause lesions, the present study aimed to characterize genotypically and phenotypically the virulence profiles of two strains of P. mirabilis isolated from cellulitis in broilers, as well as to evaluate their ability to experimentally reproduce the lesions in vivo. The strain with the highest virulence potential (LBUEL-A33) possessed mrpA, pmfA, ucaA, atfA (fimbriae), zapA, ptA (proteases), hpmA (hemolysin), and ireA (siderophore) genes, formed a very strong biofilm, and expressed the pattern of aggregative adhesion and cytotoxicity in Vero cells. The strain with the lowest virulence potential (LBUEL-A34) did not present the pmfA and ucaA genes, but expressed the pattern of aggregative adhesion, formed a strong biofilm, and did not show cytotoxicity. Both strains developed cellulitis in an animal model within 24 h post-inoculation (PI), and the degree of lesions was not significantly altered up to 120 h PI. The LBUEL-A33 strain was also inoculated in combination with an avian pathogenic Escherichia coli (APEC 046), and the lesions showed no significant changes from the individual inoculation of these two strains. Histological analysis showed that the LBUEL-A33 strain developed characteristic cellulitis lesions. Thus, both strains of P. mirabilis isolated in our study have several virulence factors and the ability to develop cellulitis in broilers.

The present study aimed to evaluate the prevalence of antimicrobial resistance and clonal relationships in Proteus mirabilis isolated from chicken meat, beef, pork, and community-acquired urinary tract infections (UTI-CA). Chicken meat isolates showed the highest multidrug resistance (MDR), followed by those from pork and UTI-CA, whereas beef had relatively few MDR strains. All sources had strains that carried blaCTX-M-65, whereas blaCTX-M-2 and blaCMY-2 were only detected in chicken meat and UTI-CA isolates. This indicates that chicken meat should be considered an important risk factor for the spread of P. mirabilis carrying ESBL and AmpC. Furthermore, ESBL/AmpC producing strains were resistant to a greater number of antimicrobials and possessed more resistance genes than non-producing strains. In addition, the antimicrobial resistance genes qnrD, aac(6′)-Ib-cr, sul1, sul2, fosA3, cmlA, and floR were also found. Molecular typing showed a genetic similarity between chicken meat and UTI-CA isolates, including some strains with 100% similarity, indicating that chicken can be a source of P. mirabilis causing UTI-CA. It was concluded that meat, especially chicken meat, can be an important source of dissemination of multidrug-resistant P. mirabilis in the community.

Salmonella spp. is one of the main agents responsible for foodborne infection in humans, and products of poultry origin are the most common infection sources. Studies have shown the occurrence of antimicrobials resistant Salmonella spp. in animal products. The Extended Spectrum ?-Lactamase (ESBL) are enzymes that confer to bacteria the ability to hydrolyze cephalosporin with an oximino side chain and monobactams. This study aimed to investigate antimicrobial resistance profile, identify phenotypes and genotypes for multiple drug resistance (MDR) and that produce ESBL from isolates of Salmonella spp. in the broiler production chain. We used samples of Salmonella spp. (n=11) isolates from poultry, poultry products and poultry-source environment from the state of Maranhão - Brazil. The isolates of Salmonella spp. assessed showed genotypical and phenotypical characteristics of MDR. The results show that 72.72% (08/11) of the strains presented the phenotypic profile for ESBL production. The isolates showed positivity to at least 13.64% (03/22) of the genes studied and the highest frequencies were observed in genes sul1 (73%), dfrA12 (55%), blaCTX-M (55%), tetA, tetB and tetC, with 45%. In conclusion, the strains of Salmonella spp. isolates present genotypic and phenotypic characteristics for MDR and ESBL production, demonstrating the dissemination risk of these microorganisms through the food chain.

After the growth-promoting antibiotics prohibition, intestinal health became an increasing concern worldwide in poultry farming. The intestinal histological evaluation is an inexpensive technique that brings relevant information, but in poultry, the immediate process of intestinal post-mortem autolysis interferes directly on the samples quality for histological analysis hindering a precise diagnosis. This study aimed to standardize a technique for broilers’ intestines sample collection and fixation for histological analysis. Seven broiler chickens received a standard diet until 23 days of age when they were euthanized. Fragments of duodenum, jejunum, and ileum were collected using three methods: intestine strips, transverse section, and Swiss roll and posteriorly fixed in 10% buffered formalin and bouin solution. Tissue samples were submitted for histological (number of villi and viable villi per field) and morphometrical (villi height, crypt depth and villi:crypt ratio) evaluations and the results analyzed statistically. A significant high number of villi and viable villi per field in all regions was observed in the Swiss roll method. In the duodenum (p= 0.0066) and jejunum (p= 0.0058) an interaction between the Swiss roll method and the fixative buffered formalin was observed in the viable and number of villi per field, respectively. Regarding the morphometrical analysis significant differences were observed, in the jejunum villi height sampling by the methods Swiss roll (1,157.66 ± 148.25 μm, p= 0.0015) that showed the highest mean. Deeper crypt depths were observed in the jejunum (156.59 ± 15.68 μm, p= 0.0002) and ileum (131.13 ± 15.01 μm, p= 0.0006) collect by the Swiss roll method. An interaction between the bouin fixative was also observed in the jejunum (p= 0.0223) for this variable. Duodenum sampling by transversal section (12.68 ± 1.45 μm, p= 0.0076) was the only segment that had a significant difference for villi:crypt ratio, showing the highest mean. It can be concluded that the Swiss roll technique was the best method for morphometrical evaluation of the chickens’ intestines, since the highest counts of villi per field and viable villi per field were obtained, while buffered formalin was considered as the best fixative.

Clostridium perfringens is the etiological agent of NE, a disease that greatly affects the poultry industry. Experiments on the induction of NE are difficult to carry out, as it is a multifactorial disease, and thus different predisposing factors have been used. This study evaluated the effect of the Gumboro disease vaccine virus vaccine (IBDV-vac) associated or not with infection by Eimeria spp. in broilers, as a predisposing factor for NE. Broilers (n = 99) were divided into groups (11) challenged with IBDV-vac, Eimeria spp. CP type G (CP13, CP14 and CP03) or both. The macroscopic evaluation revealed that the highest average (3.45) of injury occurred for the CP13 + IBDV-vac group. The microscopic analysis showed that Eimeria spp. increased the population of intraepithelial lymphocytes and reduced the villus/crypt ratio in duodenum and jejunum when associated with CP13 or CP14. There was a synergistic effect between the CP strain used and the predisposing factors; nevertheless, it was not clear which was the most effective predisposing factor to potentiate the lesions, suggesting that the association of the strain with the factors should first be evaluated for each experimental protocol.

Avian cellulitis causes significant losses to the poultry industry. Avian-pathogenic Escherichia coli (APEC) is the etiological agent of that disease. This microorganism has zoonotic potential and may act as reservoir of antimicrobial-resistance genes. In this context, the production of extended-spectrum B-lactamase (ESBL) is one of the main antimicrobial resistance mechanisms. The objective of this study was to determine the production of ESBL in an Escherichia coli (E. coli) strain isolated from avian cellulitis lesions. Twenty-two E. Coli isolates were harvested from cellulitis lesions in chicken carcasses in a commercial processing plant. Isolates were then submitted to virulence genotypic profile (iutA, hlyF, iss, ironN, ompT) analysis, antimicrobial susceptibility test, and detection of ESBL production. The results showed that 22.7% of the isolates presented five virulence genes, 9.1% four genes, 36.4% three genes, 13.6% two genes, and 18.2% one gene. The tested isolates showed resistance to ampicillin (90.9%), ceftiofur (54.5%), gentamicin (45.5%), tetracycline (72.1%), sulfamethoxazole/ trimethoprim (54.5%), and enrofloxacin (54.5%). Furthermore, 77.3% of the isolates presented multidrug resistance (MDR) profile and 72.7% were positive for ESBL production. This study is the first description of ESBL-producing APEC isolated from avian cellulitis lesions, which suggests the need to establish efficient APEC control measures and programs to prevent flock productivity losses due to colibacillosis and public health risks.