Multilocus sequence typing (MLST) of Klebsiella oxytoca from clinical specimens from Mthatha, South Africa

Abstract

Background: Klebsiella oxytoca (K. oxytoca) is an opportunistic pathogen that has been involved in various nosocomial infections such as urinary tract infections, pneumonia, wound infections, septicemia, neonatal septicemia and also hemorrhagic colitis associated with antibiotic use. Multilocus sequence typing (MLST) is a nucleotide sequence-based approach for characterising bacterial isolates. The genetic diversity and the clinical relevance of the drug-resistant K. oxytoca from Mthatha are largely unknown. For this reason, prospective, experimental study of the molecular epidemiology of selective K. oxytoca isolates from patients being treated in Mthatha was analysed. Methods & Materials: PCR amplification and sequencing of the drug-resistance-associated genes, and multilocus sequence typing (MLST) using seven housekeeping genes mdh, pgi, infB, FusAR, phoE, gapA and rpoB were conducted. A total of five isolates were analysed. Specimen types: Sputum, Eye swab, Pus (ENT source), swab of skin lesions and gastric washing. Results: Two out of five isolates were ESBL-positive and three ESBL-negative. By Sanger sequencing three isolates of K. oxytoca were misidentified as K. pneumoniae with two automated phenotypic methods. We detected 3/5 (60%) blaCTX-M and blaSHV while blaTEM were 2/5 (40%). Conclusion: With the analysis MLST using seven housekeeping genes we determined three K. oxytoca, which were mistakenly identified as K. pneumoniae by phenotypic methods.