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

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 beta-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 (R) 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). Multiplex-PCR was performed to investigate various virulence genes. Results: Amongst 61 K. pneumoniae isolates, 59% were observed as ESBL and 14.7% as AmpC producers. All ESBL 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 as follows: bla(CMY-2) (60.7%) and bla(DHA-1) (34.4%). The most frequent virulence genes were those encoding enterobactin and lipopolysaccharide. Presence of mrkD was associated with bla(DHA-1) gene, while bla(CMY-2) significantly (p=0.05) correlated with the presence of iutA and rmpA virulence genes. bla(DHA-1) positive isolates had urine as a significant source, while bla CMY-2 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. pneumoniae should be adequately considered to assess its pathogenesis and antibiotic resistance.