Shigella sonnei is an important causative agent of bacillary dysentery worldwide that has recently emerged in developing countries. However, there are few studies that have characterized strains ofS. sonnei isolated in Brazil. The aims of this study were to assess the presence of 12 virulence genes, the antimicrobial resistance profile against 16 drugs and the genotypic diversity of strains of S. sonnei isolated in this country. Seventy-two strains of S. sonnei isolated from human diarrhoeic faeces in São Paulo State, Brazil from 1983-2014 were studied. All of the strains contained the ipaH, iuc and sigA genes. The ipaBCD gene was detected in 19 % of the strains, the ial and virF genes in 18 % and the sen gene in 10 % of the strains. The set1A, set1B, pic, sepA and sat genes were not detected. A total of 42 (58.3 %) strains were resistant to trimethoprim-sulfamethoxazole. Thirty (41.6 %) strains were resistant to tetracycline. The S. sonnei strains were grouped in two clusters called A and B by PFGE and ERIC-PCR, and the majority of the strains comprised in each cluster presented !80 % similarity. In conclusion, the pathogenic potential of the strains studied was highlighted by the presence of important virulence genes. The high rates of resistance to trimethoprim-sulfamethoxazole and tetracycline are alarming once those drugs can be used in the treatment of shigellosis. The PFGE and ERIC-PCR results suggest that there are two prevalent subtypes in the studied strains of S. sonnei that differed little over 31 years and have been contaminating humans and causing diseases in São Paulo State, Brazil.

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Some studies evaluated the resistance profile of the Y. enterocolitica strains isolated in diverse countries. However, in Brazil the isolation and the study of Y. enterocolitica are not common and therefore information about the antimicrobial resistance profile of this species in this country is scarce. Therefore, the aim of this study was to evaluate the antimicrobial resistance of Y. enterocolitica of biotypes 1A, 2 and 4 isolated from clinical and non-clinical sources between 1979 and 2012, in Brazil. This study showed that some Yersinia enterocolitica of different biotypes remain susceptible to antimicrobials used for gastroenteritis treatment. Moreover, neither acquired resistance genes nor diversity of plasmids replicons were found; however, variation in the in vitro intrinsic resistant pattern was detected, except the non-resistance to cefoxitin in all strains. Notwithstanding, due to epidemiological link between Y. enterocolitica and the pork production chain, monitoring plasmid acquired resistance in Y. enterocolitica could also be considered for antimicrobial resistance control purposes and food safety measures.

The objectives of this work were to use whole genome sequencing (WGS) to determine the antimicrobial resistance genotypes of 116 Campylobacter jejuni strains isolated in Brazil and to compare it with the results obtained by antimicrobial susceptibility testing (AST). In addition, WGS was used to uncover the phylogenetic relationship among those strains. Results: By AST, the C. jejuni strains resistant to ciprofloxacin, tetracycline, doxycycline, and erythromycin were 51 (44%), 41 (35.3%), 41 (35.3%), and 6 (5.2%), respectively. By WGS, the genes aph(3¢)III, aadE, bla OXA-449 , bla OXA-184 , bla OXA-61 , and tet(O) were detected in 6 (5.2%), 3 (2.6%), 1 (0.9%), 10 (8.6%), 55 (47.4%), and 44 (38%) strains, respectively. Fifty-four (46.6%) strains showed the mutation T86I in the gyrA gene, and four (3.4%) strains presented the mutation A2075G in the 23S rRNA gene. The correlation between AST and WGS was 100% for ciprofloxacin, 97.5% for tetracyclines, and 66.7% for erythromycin. The whole genome single nucleotide polymorphism (SNP) tree clustered the C. jejuni strains into two clades comprising strains that were highly related from different sources, places, and years. Conclusion: The high rates of C. jejuni strains resistant to ciprofloxacin and tetracyclines are of concern and may represent a public health problem. WGS has a potential to be a powerful tool for the prediction of resistance of antibiotics used to treat campylobacteriosis. The results obtained by whole genome SNP analysis suggested the potential for transmission between clinical and nonclinical sources and between human and animal sources over the course of 20 years in Brazil.