Genetic fingerprinting and profile analysis of virulence genes in XDR clinical isolates of Klebsiella Pneumoniae

Abstract

Objective: Klebsiella pneumoniae, a leading cause of hospital- and community-acquired infections, requires the acquisition of drug resistance and virulence for survival in evading the host's immune responses. The investigation looks at the molecular diversity of 30 clinical isolates using rep-PCR DNA fingerprinting and the association between drug resistance and virulence genes.

Materials and methods: Isolates were cultured using basic bacteriological techniques, while antimicrobial susceptibility test and ID confirmation were made by Vitek 2 Compact Automated System (BioMerieux, Marcy L'Etoile, France). DNA used for PCR reactions was extracted with Qiagen DNA extraction kit according to the manufacturer's guidelines, while molecular genotyping by REP-PCR was carried out according to previously described methods. Some virulence genes and capsular serotypes, ybtS, mrkD, entB, rmpA, K2, Kfu, alls, iutA, and magA, were amplified by multiplex PCR.

Results: The majority (60%) of the isolates were MDR, others were XDR (37%) and susceptible strains (3%). Additionally, resistance was high (73%) for meropenem and lower (40%) for imipenem, while 97% were susceptible to ertapenem and azithromycin. DNA fingerprinting by rep-PCR showed polymorphic loci sizes that ranged from 100-2000 bp-, and phylogenetic analysis placed the isolates in seven clades with 40-96%. There was a 75% phylogenetic relatedness to antimicrobial resistance, but no specific pattern of relatedness was seen between virulence genes for the K. pneumoniae strain. Regulator mucoid phenotype A (rmpA) gene was not amplified in any of the isolates.

Conclusions: This study further confirms the presence of both MDR and XDR K. pneumonia strains. Isolates exhibited genetic diversity in phylogenetic patterns and carriage of virulence with relatedness by susceptibility to antimicrobials. Therefore, circulation could pose a risk to public health.