Multidrug-resistant Escherichia coli from free-living pigeons (Columba livia): Insights into antibiotic environmental contamination and detection of resistance genes.

Bacterial resistance is a public and one health problem. Free-living birds can be reservoirs of multidrug-resistant bacteria and resistance genes. This study aimed to characterize the antimicrobial resistance of Escherichia coli isolated from free-living urban pigeons (Columba livia) in South Brazil. Ninety-two animals were sampled, and one isolate was obtained from each one. The isolates were characterized, and the antimicrobial resistance profile and beta-lactam and colistin resistance genes were investigated. The isolates were classified as phylogroups B1 (35%), B2 (33%), A (16%) and D (16%), and 14% of the strains had the eae virulence gene. All isolates were resistant to at least one antimicrobial, and 63% of them were multidrug-resistant. Geographical location where the pigeons were captured and presence of the eae gene were associated with multidrug resistance. blaVIM and mcr-1 genes were detected in one and two isolates, respectively. This is the first report of these genes in E. coli of pigeons. The blaVIM -positive isolate was classified as Shiga toxin-producing E. coli, and the isolates with mcr-1 were classified as Enterohaemorrhagic E. coli and Enteropathogenic E. coli, which raise additional concerns related to public health since these are zoonotic pathotypes. The results reveal that pigeons carry multidrug-resistant pathogenic E. coli, which may interest public health. Nonetheless, further studies on whether these animals are sources of contamination for humans must be performed to understand their role in spreading antimicrobial resistance.

Antimicrobial Resistance of Coagulase-positive Staphylococcus Isolated From Healthy Crioulo Horses and Associated Risk Factors.

Antimicrobial resistance (AMR) is a global concern that must be addressed from a one health perspective. Horses are companion animals and their contact with humans facilitates exchange of resistant bacteria. This study aimed to evaluate AMR of coagulase-positive Staphylococcus (CoPS), including Staphylococcus aureus, isolated from healthy Crioulo horses. Swab samples from nostrils (n = 214) and skin (n = 107) of 107 horses from Porto Alegre, South Brazil, were used for CoPS isolation. The isolates were evaluated for AMR and a multivariate logistic regression was applied to identify the risk factors associated to this outcome, using information on horses' management and installations where they were maintained. A total of 143 CoPS were isolated from 79 horses (73.8%), of which 8 (5.6%) were S. aureus. The isolates showed resistance to seven of 10 tested antimicrobials and 38.5% (55/143) of them were resistant to at least one antimicrobial. One isolate (0.7%; 1/143) was classified as multidrug-resistant. Regarding S. aureus, 62.5 % (5/8) showed AMR, but none were methicillin-resistant. The risk factors associated with CoPS' antimicrobial resistance were lower frequency of bed changing (OR = 6.40; P = .001) and nonaccumulation of bed materials (OR = 3.47; P = .002). The results point that healthy horses have antimicrobial-resistant CoPS and S. aureus in their microbiota, which may be of concern for animal and human health. Moreover, bed management was associated with AMR, which can serve as a guide for best practices to be adopted to avoid the occurrence of resistant bacteria in these animals.

A molecular strategy to optimize bovine tuberculosis post-mortem diagnosis and the exposure to Mycobacterium tuberculosis variant bovis.

Bovine tuberculosis (bTB) is a zoonotic disease caused by Mycobacterium tuberculosis var. bovis, for which the definitive diagnosis is accomplished by bacterial isolation, which has biosafety issues and requires long time. Thus, diagnostic methods with potential to be faster and more efficient can represent an advance in bTB epidemiological knowledge and decrease exposure to M. tuberculosis var. bovis. This study aimed to validate a molecular test for bTB post-mortem diagnosis, as a strategy to reduce waste in bovine production. A total of 185 tissues from animals of infected herds or with suspected lesions at abattoir were evaluated through bacterial isolation, PCR and histopathology. PCR and histopathology showed sensitivities of 45.1% and 71.2%, respectively, and specificities of 83.3% and 83.0%, respectively, when compared to bacterial isolation. The combination of both tests resulted in enhanced specificity and positive predictive values.Therefore, PCR in conjunction with histopathology may be used as screening, in which concordant results can be considered conclusive, and discordant results may be submitted to bacterial isolation.

Probióticos e resposta imune / Probiotics and immune response

Os probióticos são bactérias que produzem efeitos benéficos no hospedeiro, usadas para prevenir e tratar doenças, como promotores de crescimento e como imunoestimulantes. Nesta revisão abordam-se as principais aplicações dos probióticos, com ênfase nas informações recentes sobre suas propriedades de modular a resposta imune.