Screening of Klebsiella pneumoniae isolates reveals the spread of strong biofilm formers and class 1 integrons

Aims: Klebsiella pneumoniae is a Gram-negative bacterium that can colonize, penetrate, and cause infections at several human anatomical locations. The emergence of hypervirulent K. pneumoniae and its ability to evade the immune system and develop antibiotic resistance has made it a key concern in the healthcare industry. The hypervirulent variants are increasingly involved in community-acquired infections. Therefore, it is pertinent to understand the biofilm formation potential among the clinical isolates. Methods and results: We acquired 225 isolates of K. pneumoniae from the Department of Microbiology, Symbiosis University Hospital and Research Centre (SUHRC), Pune, India, over 1 year from March 2022 to March 2023, and evaluated antimicrobial susceptibility, hypermucoviscous phenotype, virulence, and antimicrobial-resistant gene distribution in K. pneumoniae isolates and established a correlation between antimicrobial resistance and integrons. Most isolates were strong biofilm formers (76%). The isolates harbored one or more carbapenemase/beta-lactamase-encoding gene combinations. Hypermucoviscous (HMKP) isolates had considerably greater positive rates for iutA, magA, K2 serotype, rmpA, and rmpA2 than non-HMKP isolates. Isolates carrying integrons (43%) showed significantly more antibiotic resistance. Conclusion: The study reveals spread of strong biofilm formers with extensive virulence and antimicrobial-resistant genes, and integrons responsible for multidrug resistance among the clinical isolates of K. pneumoniae in Pune, India, posing a threat to the public health and necessitating close surveillance, accurate diagnosis, control, and therapeutic management of infections.