Detection of hypervirulent <i>Klebsiella pneumoniae</i> among clinical isolates from select infections using virulence gene markers

Objectives Hypervirulent Klebsiella pneumoniae (hvKp) is a distinct pathotype of K. pneumoniae associated with community-acquired infections, and it generally exhibits susceptibility to antimicrobial agents. The objective of the study was to identify hvKp and determine the antibiotic susceptibility profiles of these isolates. Materials and Methods A total of 150 K. pneumoniae isolates were obtained from community-acquired infections. All isolates were subjected to string test and antimicrobial susceptibility test using Kirby–Bauer disc diffusion. Final confirmation was done using polymerase chain reaction (PCR), targeting three hvKp-specific virulence genes (p rm pA, iu cA, and pe g344). Statistical analysis The associations between the string test and virulence genes were assessed using the Chi-square test. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the string test were calculated using PCR as the gold standard. Results Among the 150 isolates, 62 (41.3%) were identified as hvKp. Abscesses (29) and pneumonia (22) were the most common clinical conditions, with neck abscesses as the predominant site. Of the 62 hvKp isolates, only 44 were string test-positive. Surprisingly, 22 string test-positive isolates lacked these genes, while 18 string test-negative isolates carried virulence genes. The sensitivity, specificity, PPV, and NPV of the string test were 66.7%, 78.5%, 71%, and 75%, respectively. Three hvKp isolates were multidrug-resistant. Conclusions Accurate detection of hvKp is critical in clinical settings due to its association with severe community-acquired infections, including deep-seated abscesses and pneumonia. The string test lacks both sensitivity and specificity, making it unreliable for hvKp identification. Therefore, the detection of virulence genes remains the gold standard. Early and precise diagnosis is essential for guiding appropriate treatment, including targeted antibiotic therapy and necessary drainage procedures for abscesses. The presence of multidrug resistance in certain isolates is a cause for concern, necessitating strict infection control measures to prevent the spread of such strains.