Virulence characterization of Klebsiella pneumoniae and its relation with ESBL and AmpC beta-lactamase associated resistance

Abstract

Background and Objectives: Trend analysis reveals that Klebsiella pneumoniae has witnessed a steep enhancement in the antibiotic resistance and virulence over the last few decades. The present investigation aimed at a comprehensive approach investigating antibiotic susceptibility including, extended spectrum beta-lactamase (ESBL) and AmpC β-lactamase (AmpC) resistance and the prevalence of virulence genes among the K. pneumoniae isolates.

Materials and Methods: Sixty-one K. pneumoniae isolates were obtained from various clinical infections. Antimicrobial susceptibility was performed by disk diffusion method. The Mast® D68C test detected the presence of ESBLs and AmpCs phenotypically, and later presence of ESBL and AmpC genes was observed by polymerase chain reaction (PCR). Multi- plex-PCR was performed to investigate various virulence genes.

CMY-2

 

Results: Amongst 61 K. pneumoniae isolates, 59% were observed as ESBL and 14.7% as AmpC producers. All ESBL

CTX-M-15

 

producers were positive for bla

CTX-M-15

, while bla

CTX-M-14

was observed in 54.1% isolates. The frequency of AmpC genes was

CMY-2

 

as follows: bla

CMY-2

(60.7%) and bla

DHA-1

(34.4%). The most frequent virulence genes were those encoding enterobactin and

DHA-1

 

lipopolysaccharide. Presence of mrkD was associated with bla

CMY-2

 

DHA-1

gene, while bla

significantly (p≤0.05) correlated

DHA-1

 

with the presence of iutA and rmpA virulence genes. bla

positive isolates had urine as a significant source, while bla

positive isolates were mainly collected from wound exudates (p≤0.05).

Conclusion: Our results highlight that ESBL and AmpC production along with a plethora of virulence trait on K. pneumoni- ae should be adequately considered to assess its pathogenesis and antibiotic resistance.