Molecular characterisation of multidrug-resistant Klebsiella pneumoniae belonging to CC258 isolated from outpatients with urinary tract infection in Brazil.

OBJECTIVES: This study characterised 48 Klebsiella pneumoniae isolates from outpatients with urinary tract infection in the micro-region of Ribeirão Preto, located in southeastern Brazil.

METHODS: The isolates were identified by conventional biochemical and phenotypic tests and were confirmed as K. pneumoniae using a MALDI-TOF VITEK® MS system. Antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the Clinical and Laboratory Standards Institute (CLSI) using 38 different antibiotic discs. Fifteen β-lactamase and ten virulence genes were investigated by PCR. Clonal relationships among the isolates were determined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and multilocus sequence typing (MLST).

RESULTS: Of the 48 isolates, 29 (60.4%) were classified as multidrug-resistant. A total of 46 β-lactamase genes were found in 27 (56.3%) of the isolates, with blaKPC being the most prevalent distributed in 18 isolates (37.5%). Moreover, 73 virulence genes were found in 30 isolates (62.5%). ERIC-PCR results showed high genetic diversity among the isolates. Twelve different sequence types (STs) were found by MLST (ST14, ST17, ST101, ST200, ST334, ST433, ST437, ST442, ST449, ST502, ST1246 and ST2729), with ST2729 being described for the first time in this study. Seven STs were grouped in clonal complex 258 (CC258) frequently associated with various resistance and virulence genes.

CONCLUSIONS: These results raise concern about epidemiological surveillance related to colonisation of patients discharged from hospitals in order to prevent both the occurrence and spread of resistant bacterial infections in the community.