Genetic relatedness, virulence factors and antimicrobial resistance of C. difficile strains from hospitalized patients in a multicentric study in Brazil

Abstract

Background: Clostridium (Clostridioides) difficile infection (CDI) is recognized worldwide as a public health concern, related mainly with hypervirulent strains. In Brazil there are few studies about molecular epidemiology of C. difficile, for this reason, we aimed to characterize C. difficile isolates from a large cohort study of three different Brazilian states to identify virulence and resistance genes, specifically genes related to metronidazole and vancomycin resistance. Methods: All 153 fecal samples were submitted to C. difficile culture in CM0601 broth. Identification of suspected colonies was confirmed by matrix-assisted laser desorption/ionization (MALDI-TOF/MS, Brucker Daltonics, Germany). The tcdA and tcdB toxin were searched by PCR. The sequence type (ST) was determinate by multilocus sequencing typing (MLST) and susceptibility profile was performed by agar dilution method. Results: Among the 16 isolates, we identified fourteen different STs, five belonging to Clade 1, one to Clade 2 and eight news STs with high similarity levels. Resistance (ermB, tetM, VanW and nimB) and virulence genes (cwp84, cwp66, cwp2, fbpA and secA) were found in toxigenic strains. Conclusion: Differently from other studies, we found high levels of resistance to vancomycin. These results suggest that the main circulating strains in Brazil belong to Clade 1 and have high pathogenicity and resistance profile.