Detection of Hypervirulent Klebsiella pneumoniae from Clinical Samples in Tamil Nadu

Klebsiella pneumoniae is one of the significant opportunistic pathogens which cause both nosocomial and community-acquired infections. This study focuses on the molecular characterization of hypervirulent K. pneumoniae isolated from clinical samples in Tamil Nadu. A total of 30 clinical K. pneumoniae isolates were collected from the diagnostic centres located in Trichy, Madurai, and Chennai. On subjected to the antibiotic susceptibility testing, it was found that 73% were multi-drug resistant. The string test showed that 46.6% of the isolates were hypermucoviscous (HMV). Molecular studies revealed the absence of mcr (1-5) genes. The isolates belonging to capsular types K1 (n=5), K2 (n=6) and K5 (n=2) were detected. Virulence genes namely rmpA (n=5), aerobactin (n=8), and KfuBC (n=8) were identified using multiplex polymerase chain reaction. Through molecular studies, 22 isolates were found to be classical K. pneumoniae (cKP) and 8 were hypervirulent K. pneumoniae (hvKP). The genome sequencing of five isolates revealed that the strains belong to ST86 and ST23. In vivo studies using Galleria mellonella showed that HMV-hvKP strains were highly pathogenic among the hvKP strains and the non-K1/K2 and K2 strains were pathogenic among the cKP strains. Our data revealed the emergence of colistin-resistant hvKP strains in Tamil Nadu, India.