Salmonella Typhimurium ST313 isolated in Brazil revealed to be more invasive and inflammatory in murine colon compared to ST19 strains.

Salmonella Typhimurium (ST313) has caused an epidemic of invasive disease in sub-Saharan Africa and has been recently identified in Brazil. As the virulence of this ST is poorly understood, the present study aimed to (i) perform the RNA-seq in vitro of S. Typhimurium STm30 (ST313) grown in Luria-Bertani medium at 37°C; (ii) compare it with the RNA-seq of the S. Typhimurium SL1344 (ST19) and S. Typhimurium STm11 (ST19) strains under the same growing conditions; and (iii) examine the colonization capacity and expression of virulence genes and cytokines in murine colon. The STm30 (ST313) strain exhibited stronger virulence and was associated with a more inflammatory profile than the strains SL1344 (ST19) and STm11 (ST19), as demonstrated by transcriptome and in vivo assay. The expression levels of the hilA, sopD2, pipB, and ssaS virulence genes, other Salmonella pathogenicity islands SPI-1 and SPI-2 genes or effectors, and genes of the cytokines IL-1ß, IFN-γ, TNF-α, IL-6, IL-17, IL-22, and IL-12 were increased during ST313 infection in C57BL/6J mice. In conclusion, S. Typhimurium STm30 (ST313) isolated from human feces in Brazil express higher levels of pathogenesis-related genes at 37°C and has stronger colonization and invasion capacity in murine colon due to its high expression levels of virulence genes, when compared with the S. Typhimurium SL1344 (ST19) and STm11 (ST19) strains. STm30 (ST313) also induces stronger expression of pro-inflammatory cytokines in this organ, suggesting that it causes more extensive tissue damage.

Molecular Epidemiology and Resistance Profile of Campylobacter jejuni and Campylobacter coli Strains Isolated from Different Sources in Brazil.

Aims: The objectives of this study were to genotype a total of 48 Campylobacter jejuni and 39 Campylobacter coli strains isolated in Brazil from 1995 to 2016 by multilocus sequence typing (MLST) and to determine their resistance profile. The presence or points of mutation in the related resistance genes was verified. Results: By MLST, C. jejuni strains were typed into 36 STs and C. coli strains were typed into 27 STs. A total of 70.8% of C. jejuni and 35.9% of C. coli were resistant to at least one antimicrobial tested. The tet(O) gene was detected in 43.7% C. jejuni and in 12.8% C. coli. The ermB gene was not detected and one C. jejuni presented the mutation in the 23S rRNA gene. Besides, 58.3% C. jejuni presented the substitution T86I in the quinolone resistance-determining region of gyrA and 15.4% C. coli presented the substitution T38I. The cmeB gene was detected in 97.9% C. jejuni and in 97.4% C. coli. Conclusion: The presence of C. jejuni and C. coli resistant to some antimicrobial agents of clinical use is of public health concern. The presence of STs shared between Brazilian strains and isolates of different countries is of concern since it might suggest a possible spread of these shared types.

Molecular typing and occurrence of beta-lactam resistance genes of Shigella sonnei strains isolated from 1983 to 2014 in the São Paulo state of Brazil.

Shigella sonnei, which has generally been associated with dysentery in developed countries, has recently been emerging in developing countries. Specifically, in Brazil few published studies have that molecularly characterized this species. The aims of this study were to analyze the efficacy of typing using multiple-locus variable-number tandem-repeat analysis (MLVA), study the phylogeny by multi-locus sequence typing (MLST) and assess the presence of some beta-lactam resistance genes in S. sonnei strains isolated from human diarrhoeic faeces in the São Paulo State in Brazil between 1983 and 2014. Seventy-two such S. sonnei strains were typed by MLVA and grouped into two clusters. The discrimination index of MLVA was found to be 0.996. Twenty strains were typed by MLST as ST152. In addition, the blaTEM gene was detected in eight (72.7%) of the 11 S. sonnei strains that had previously been shown to be resistant to ß-lactams. However, blaCTX-M-1group , blaCTX-M-9group and blaSHV genes were not found. MLVA results suggested the existence of two prevalent subtypes in the S. sonnei strains studied, confirming previous results. Moreover, MLVA efficiently discriminated monomorphic S. sonnei species. Because the S. sonnei strains studied belonged to clonal complex 152 and all isolates were typed as ST152, MLST is not a suitable method for studying the population structure of S. sonnei. Although, the rates of ß-lactam resistance were not high in the present study, the frequency of blaTEM may represent a risk for patients receiving antimicrobial treatment. Taken together, the results provide better molecular characterization of this globally clinically important pathogen.

Molecular and phenotypic characterization of strains of Shigella sonnei isolated over 31 years suggests the circulation of two prevalent subtypes in São Paulo State, Brazil.

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.

Acinetobacter species in clinical specimens: biotypes and serotypes of acinetobacter baumannii strains isolated in Säo Paulo, Brazil

Foram estudadas 190 cepas de Acinetobcter (76 isoladas de líquido cefalorraquidiano, 30 de sangue e 84 de outros materiais clínicos), isoladas no período 1986-92, em Säo Paulo, Brasil. As espécies foram identificadas segundo Bouvet and Grimont e Vouvet and Jeanjean. Os sorotipos e biotipos foram determinados para A. baumannii seguindo os métodos descritos por Traub e Bouvet and Grimont, respectivamente. Entre as 10 espécies identificadas, o A.baumannii (60 por cento) e A.genospecies 3 (11.6 por cento) foram as mais frequentes. Verificou-se que os biotipos 2,6, e 9 e os sorotipos 04, 015 e 029 foram predominantes entre as cepas de A.baumannii