Current molecular genetic technologies to study hospital strains

Abstract

The aim of the study was to assess the efficiency of a complex of molecular genetic techniques: PCR, RAPD, and MLST using MALDI-TOF mass-spectrometry to study the characteristics of hospital strains. Materials and Methods. We identified 23 strains of K. рneumoniae isolated in a pediatric hospital using MALDI-TOF mass-spectrometer Autoflex and MALDI Biotyper software (Bruker Daltonics, Germany). Antibiotic sensitivity was analyzed by means of an automatic bacteriological analyzer Phoenix-100 (Becton Dickinson, USA) using chromogenic culture media (HiMedia, India). The search for resistance determinants and molecular typing were performed using PCR, RAPD, and MLST. Results. All the strains were identified as K. pneumoniae ssp. pneumoniae. According to antibiotic sensitivity, three groups were distinguished: group 1 (n=15) — sensitive strains (wt); group 2 (n=7) — potential carbapenemase-producers; group 3 (n=1) — extended-spectrum beta-lactamase producers. No resistance determinants were found in groups 1 and 2; beta-lactamases blaSHV and blaCTX-M were revealed in group 3 strain. We identified RAPD-type of the strain, a capsule type (K-23), it belonging to the sequence type 17. Strains with this sequence type are rarely isolated in Russia, however, they are known in Europe, USA, and Asian countries, they being associated with lethal human pathologies and a high epidemic potential. Conclusion. The use of a complex of current techniques to study the phenotypic and genotypic properties of microorganisms enabled to isolate and characterize a hospital strain K. pneumoniae, which is antibiotic-resistant due to the presence of beta-lactamases: blaCTX-M-15 and blaSHV-11, and it being dangerous in terms of resistance determinants transmission.