Banca de DEFESA: PAULO ROBERTO LIMA DE AZEVEDO JUNIOR

Analysis of microbial diversity and the colisitin resistance profile in enterobacteria present in poultry production environments:

a comparative study with a focus on One Health

poultry farming, microorganisms, microbiome, genes, One Health.

Poultry farming is one of the fastest growing agricultural sectors of agribusiness around the world. Among the world's main producers are the USA, Brazil and China. Currently, the important role played by the microbiota and microbiome in the health, performance and well-being of poultry is recognized. In this context, the use of antimicrobials as growth promoters in the poultry industry is one of the factors that increase environmental selection pressure, favoring the emergence and dispersion of antimicrobial resistance, and consequently generating an impact on Unique Health, as it affects the balance of the interdependence between human, animal and environmental health. In the context of broiler chicken production, One Health is related to the health of the production environment, workers and consumers. The focus of the present study is resistance to colistin, a polymyxin (polymyxin E) that has a broad spectrum of action against Gram-negative bacteria, promoted by the mcr genes. After the discovery of the mcr-1 plasmid gene in 2015, its use as a growth promoter was banned in several countries, including Brazil. This work aimed to evaluate the occurrence, diversity and phenogenotypic resistance to colistin of enterobacteria in poultry production environments. Samples from the cloaca, trachea and bed resulted in 301 isolates, 162 (53.8%) from the cloaca, 121 (40.2%) from the trachea and 18 (6%) from the environment. Of these isolates, 175 (58.1%) were Firmicutes, 120 (39.9%) were Proteobacteria and 6 were Actinobacteria. Regarding genus/species, 102 (33.9%) isolates were coagulase-negative Staphylococcus (ECN); 82 (27.2%) E. coli; 53 (17.6%) Enterococcus spp.; 27 (9%) Proteus mirabilis; 10 (3.3%) Bordetella hinzii; 8 (2.7%) Streptococcus spp.; 7 (2.3%) Ligilactobacillus salivarus; 6 (2%) Corynebacterium spp.; 4 (1.3%) Lactobacillus johnsonii; 1 (0.3%) Salmonella spp. and 1 (0.3%) Aerococcus viridans. Of the 83 isolates phenotypically tested for colisitin resistance, 15 (18.1%) were resistant. Of the 110 enterobacteria strains evaluated for the detection of mcr genes, 102 (92.7%) strains were positive. Of these 102 mcr-positive strains, 48 (47.1%) were mcr-1, 42 (41.2%) mcr-2, 27 (26.5%) mcr-3, 61 (50%) mcr-4, 7 (6.7%) mcr-5, 40 (39.2%) mcr-6, 1 (1%) mcr-7, 4 (3.9%) mcr-8 and 39 (38.2%) for mcr-9. Of the 269 genes detected, 48 (17.8%) were mcr-1, 42 (15.6%) mcr-2, 27 (10%) mcr-3, 61 (22.7%) mcr-4, 7 ( 2.6%) mcr-5, 40 (14.9%) mcr-6, 1 (0.4%) mcr-7, 4 (1.5%) mcr-8 and 39 (14.5%) mcr -9. Of the 15 isolates resistant to colistin, 12 (80%) mcr were detected. Of the 68 colisitin-sensitive strains, mcr were detected in 63 (94%). Of the 102 (72.5%) were E. coli, 27 (25.5%) P. mirabilis and 1 (1%) Samonella sp. 159 (59.1%) of these genes were detected in E. coli, 108 (40.1%) in P. mirabilis and 2 (0.7%) in Salmonella sp. Comparing the results with those obtained by Pimenta (2018), it was observed that there was a drop in both resistance to colisitna and the prevalence of mcr-1. Several genera/species of great importance in Single Health are found in poultry production environments and the circulation of mcr family genes in these environments is still high, despite the advent of IN45/2016, pointing to the fact that the average range of 6 years of this study after the ban, it was still not enough for a significant reduction in mcr circulation in poultry production, which represents a serious problem in One Health.