Microbiological and Clinical Characteristics of Hypervirulent Klebsiella pneumoniae isolated from Patients in Tertiary Centers

Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a significant pathogen capable of causing severe community-acquired infections in otherwise healthy people. This cross-sectional, retrospective study aimed to investigate the prevalence of hvKp, its virulence-associated genes, and the clinical manifestations of hvKp infections. HvKp was defined in this study as K. pneumoniae with a positive string test and harbouring the serotype K1 or K2 gene. A total of 180 isolates from various clinical specimens were collected from June 2020 to June 2021 in four main hospitals in Kelantan. All isolates were examined for hypermucoviscous phenotype by string test, while the presence of capsular serotype and other virulence genes (rmpA, rmpA2, iucA, magA, peg-344) was done by PCR. Patients clinical data was collected and analyzed. String test positive isolates (23.8%, n = 43) were identified as hypermucoviscous K. pneumoniae (hmKp). Capsular serotypes K1 and K2 were detected in 11.1% (n = 20) and 6.1% (n = 11), respectively. The prevalence of hvKp was found to be 9.4% (n = 17). All the hvKp isolates were positive for rmpA, rmpA2, iucA, and peg-344 genes, while all ten hvKp-K1 serotypes were positive for magA, the K1serotype-specific gene. The associations of all the corresponding virulence genes with both serotypes K1 and K2 were statistically significant (p<0.05). HvKp infections were more prevalent in men and individuals with hypertension. Pneumonia was the leading clinical diagnosis in hvKp infected patients, with the mortality rate was 12%. The presence of all biomarkers (rmpA, rmpA2, magA (for K1 serotype), iucA, and peg-344 in hmKp, in combination with clinical manifestations, might be reliable for hvKp diagnosis and epidemiological surveillance.