Consumption of raw, undercooked or contaminated animal food products is a frequent cause of Campylobacter jejuni infection. Brazil is the world’s third largest producer and a major exporter of chicken meat, yet population-level genomic investigations of C. jejuni in the country remain scarce. Analysis of 221 C. jejuni genomes from Brazil shows that the overall core and accessory genomic features of C. jejuni are influenced by the identity of the human or animal source. Of the 60 sequence types detected, ST353 is the most prevalent and consists of samples from chicken and human sources. Notably, we identified the presence of diverse bla genes from the OXA-61 and OXA-184 families that confer beta-lactam resistance as well as the operon cmeABCR related to multidrug efflux pump, which contributes to resistance against tetracyclines, macrolides and quinolones. Based on limited data, we estimated the most recent common ancestor of ST353 to the late 1500s, coinciding with the time the Portuguese first arrived in Brazil and introduced domesticated chickens into the country. We identified at least two instances of ancestral chicken-to-human infections in ST353. The evolution of C. jejuni in Brazil was driven by the confluence of clinically relevant genetic elements, multi-host adaptation and clonal population growth that coincided with major socio-economic changes in poultry farming.

Introduction: The intensification of tilapia production has increased animal density in tanks, leading to more frequent exposure to pathogenic agents and compromising the quality of fish products. Antimicrobial resistance is a global concern that affects human treatment, and sentinel microorganisms like Escherichia coli are crucial for monitoring production chains, especially in aquaculture, where research is still limited. The aim of this study was to identify the presence of E. coli and investigate its antimicrobial resistance profiles throughout the entire tilapia production chain.Methods: A total of 240 samples were collected from various points in the production process: carcasses before scaling (Ca), scaling wastewater (Sw), filleting wastewater (Fw), fillet washing wastewater (Tw), fillet handling surfaces (Su), and pre-packaged fillets (Pf). The samples were collected during 10 visits, each corresponding to animals from different farms. E. coli isolates were identified using MacConkey agar and biochemical tests. Phenotypic resistance profiles were determined using nine classes of antimicrobials. Extended- spectrum b-lactamase (ESBL) production was identified with ceftazidime and cefotaxime and confirmed by a double-disc synergy test. Isolates were classified as sensitive or resistant based on the inhibition zone. Multidrug-resistant (MDR) was defined as resistance to at least one agent in three or more antimicrobial categories, while extensively drug-resistant (XDR) was defined as resistance to at least one agent in all but two or fewer categories.Results: Overall, 50.8% of the samples (122/240) tested positive for E. coli, with 403 isolates identified. Of these, 33% (133/403) were resistant to at least two antimicrobials, and 20% (48/240) of the samples had MDR isolates, with the highest frequency found at the filleting point (Fw), which also had the only XDR profile. Resistance was most commonly observed against amoxicillin (35.73%), tetracycline (30.77%), and ciprofloxacin (26.30%).Discussion: These findings emphasize the importance of E. coli as an indicator of antimicrobial resistance throughout tilapia processing and highlight the need for good production practices and qualified technical support to mitigate risks to public health, animal health, and the environment.

Campylobacter coli is a ubiquitous commensal in the gut of birds and mammals. It causes acute gastroenteritis in humans when contaminated livestock meat is consumed and can be fatal in vulnerable individuals. Here, we aim to characterize the population genomic structure and antimicrobial resistance (AMR) dissemination of C. coli in Brazil contextualized against a South American background. We analyzed 32 newly sequenced short-read genomes from Brazil and 158 previously sequenced genomes from different locations in South America. Clonal complex CC828, which is known to be predominant in agriculture and human diseases, accounted for 82.4% of the Brazilian genomes (n = 108). We identified six mutations, 15 acquired genes, and one operon (cmeABC) that were associated with AMR in the Brazilian population. Six AMR determinants (aad9, aph(3')-IIIa, gyrA T86I, 23S A2075G, blaOXA-460, tet(O)) displayed co-occurrence albeit at different paired combinations and probabilities. The Brazilian genomes showed close phylogenetic relationship with those from Chile, Ecuador, and Peru. Across the four countries, AMR determinants associated with putative plasmids or transposable elements included those related to aminoglycosides, streptothricin, tetracyclines, and multidrug resistance. The widespread dissemination of CC828 and their mobile genetic elements shape AMR distribution in C. coli across Brazil. A long-term epidemiological and genomic surveillance system in the country will be useful to determine how campylobacteriosis can be controlled effectively and the scale at which interventions need to be enforced.

The aim of this study was to evaluate the influence of different periods of pre-slaughter fasting (F1: 2 to 24 hours and F2: 48 to 72 hours) on the counts of hygiene indicator microorganisms and the presence of Salmonella spp. in carcasses of bullfrogs. Two different stages of the slaughter process were analyzed: after bleeding (A) and after the final carcasses cleaning (B). Samples from each fasting period were analyzed to count hygiene indicator microorganisms (n=30) and Salmonella spp. (n=140). For aerobic mesophilic microorganisms, the variation in fasting periods caused a reduction of 0.69 log10 CFU / g (P0.05) between the fasting analyzed periods. Considering the presence of E. coli, it was observed that F2 resulted in a reduction of 30% (P<0.05) positivity on point B. For Salmonella spp., the results showed that F2 contributed to an 11.5% reduction in the presence of this bacteria at point B. (P<0.05). Therefore, it is concluded that 48 to 72 hours of pre-slaughter fasting resulted in a positive impact on the microbiological quality of bullfrog carcasses.