Investigations of carbapenem resistant and hypervirulent Klebsiella pneumoniae

Hypervirulent Klebsiella pneumoniae is an emerging pathogen that has gained attention due to its increased ability to cause infections even in healthy individuals. The aim of this study is to investigate virulence factors in K. pneumoniae strains isolated from clinical specimens and their association with carbapenem resistance. The study was conducted on 260 isolates identified between 2018 and 2023 at the Mohammed V Military Teaching Hospital in Rabat, Morocco. The isolates were categorized based on their susceptibility to antibiotics. The hypermucoviscosity was determined by a string test, while the presence of capsular serotypes and virulence genes were identified by PCR. Among our strains, 6.2% (n = 16) exhibited hypervirulent characteristics, 56% were resistant to carbapenem. Notably, 5.7% (n = 6) of carbapenem-resistant isolates expressed the hypermucoviscous phenotype, while 1.5% (n = 2) of carbapenem-susceptible K. pneumoniae isolates exhibited the same trait. In our study, we found that a total of 10 isolates (3.8%) had virulent capsular serotypes, with K2 being the most prevalent 40% (n = 4) and K20 in 30% (n = 3). Furthermore, we detected the presence of the Aerobactin gene in 1.5% (n = 4) of the isolates examined. Based on our findings, it appears that there was no correlation between the presence of virulence factors and carbapenem resistance. In conclusion, identifying hypervirulent K. pneumoniae in clinical specimens and assessing their antibiotic resistance profiles are crucial to ensure effective therapy and to prevent outbreaks.