In animal husbandry, antimicrobial agents have been administered as supplements to increase production over the last 60 years. Large-scale animal production has increased the importance of antibiotic management because it may favor the evolution of antimicrobial resistance and select resistant strains. Brazil is a significant producer and exporter of animal-derived food. Although Brazil is still preparing a national surveillance plan, several changes in legislation and timely programs have been implemented. Thus, Brazilian data on antimicrobial resistance in bacteria associated with animals come from official programs and the scientific community. This review aims to update and discuss the available Brazilian data on this topic, emphasizing legal aspects, incidence, and genetics of the resistance reported by studies published since 2009, focusing on farm animals and derived foods with the most global public health impact. Studies are related to poultry, cattle, and pigs, and mainly concentrate on non-typhoid Salmonella, Escherichia coli, and Staphylococcus aureus. We also describe legal aspects of antimicrobial use in this context; and the current occurrence of genetic elements associated with resistance to beta-lactams, colistin, and fluoroquinolones, among other antimicrobial agents. Data here presented may be useful to provide a better understanding of the Brazilian status on antimicrobial resistance related to farm animals and animal-derived food products.

Multidrug-resistant (MDR) Staphylococcus aureus has been increasingly isolated from pigs and people in close contact with them, especially livestock-associated methicillin-resistant S. aureus (LA-MRSA). In this cross-sectional study, we investigated S. aureus colonization in pigs and farm workers, their resistance profile, and genetic background to estimate interspecies transmission potential within farms from Rio de Janeiro state, Brazil, between 2014 and 2019. We collected nasal swabs from 230 pigs and 27 workers from 16 and 10 farms, respectively. Five MDR strains were subjected to whole genome sequencing. Fourteen (6.1%) pigs and seven (25.9%) humans were colonized with S. aureus, mostly (64–71%) MDR strains. Resistance to clindamycin, erythromycin, penicillin, and tetracycline was the most common among the pig and human strains investigated. MDR strains shared several resistance genes [blaZ, dfrG, fexA, lsa(E), and tet(M)]. Pig and human strains recovered from the same farm shared the same genetic background and antimicrobial resistance profile. LA-MRSA ST398-SCCmecV-t011 was isolated from pigs in two farms and from a farm worker in one of them, suggesting interspecies transmission. The association between pig management practices and MDR S. aureus colonization might be investigated in additional studies.

Background: For over 70 years, guidelines have recommended antibiotics for infective endocarditis (IE) prophylaxis before dental procedures, focusing on oral streptococci. Objectives: Our in silico study aimed to evaluate the potential resistance of oral streptococci against prophylactic antibiotics used before invasive dental procedures to prevent IE. Methods: The genomic assemblies and metadata of Streptococcus IE isolates were searched using specific terms in BioSample and RefSeq databases. Their antimicrobial resistance phenotypes for 91 drugs belonging to 22 different classes were predicted with ResFinder and analysed regarding the recommended IE dental prophylactic antibiotics, focusing on the oral streptococci assemblies. Results: Among the 258 Streptococcus isolates dating from 1935 to 2021 from 12 countries, 79.46% were classified as oral streptococci, and 38.37% of the 258 assemblies carried resistance genes to at least one antimicrobial. Seven isolates carried the transposon Tn6331, which can confer resistance to aminoglycosides, macrolides, lincosamides, streptogramins and tetracyclines. Within the oral Streptococcus strains, none carried resistance genes to amoxicillin, but potential resistance to azithromycin (24.88%) and doxycycline (16.59%) was observed. Conclusions: Our in silico study showed that none of the oral Streptococcus assemblies from IE carried resistance genes to the primary regimen recommended for IE prophylaxis following invasive dental procedures. However, several assemblies were potentially resistant to alternative prophylactic regimens for patients allergic to penicillin or ampicillin.

The Tricycle Protocol is a One Health initiative that involves monitoring extended-spectrum β-lactamase-producing Escherichia coli (ESBL-Ec), an opportunistic intestinal and extraintestinal pathogen that is recognized as critically important for the development of new antimicrobial agents and as a key indicator of water, food, and environmental contamination. This study aimed to detect and characterize, phenotypically and genotypically, the presence of ESBL-Ec in coastal waters collected from three urban marine ecosystems and mussels from a mariculture area in the metropolitan region of Rio de Janeiro City, Brazil. Eighteen samples from each beach and from mussels were collected between June 2022 and December 2023. A total of 299 E. coli strains were identified over the study period, of which 33 (11%) were initially identified as potential ESBL producers after selective pressure cultivation. Antimicrobial susceptibility analysis revealed a high frequency of resistance to ampicillin and third-generation cephalosporins, exceeding 80%. Eighteen (54.4%) of the 33 E. coli strains were classified as multidrug resistant (MDR). Genotypic confirmation revealed at least one ESBL gene ( bla _CTX-M-1,2 , bla _CTX-M-8 , bla _CTX-M-14 , bla _TEM , or bla _SHV ) in 30 of the 33 strains, with bla _CTX-M-1,2 being the most prevalent in samples from one estuarine beach and from the mariculture site. Additionally, the genes qnrS , intl1 , and intl2 were detected in 21.5%, 7.6%, and 1.3% of the confirmed ESBL-Ec strains, respectively. Since we could not associate the presence of MDR ESBL-Ec strains with unsuitable water classification, these findings underscore a grave threat to both human and animal health in densely inhabited coastal regions.