Genetic analysis of virulence factors of MDR Klebsiella pneumoniae spp. pneumoniae isolated from clinical specimens - study from a tertiary care hospital

• Author Details:   
• Bhavita Thakorbhai Prajapati
• Anant Prabhakar Marathe ^*
• Asmabanu Mahammed Hanif Shaikh
• Shital Sangani

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Background: Klebsiella pneumoniae is a predominant nosocomial pathogen owing to its potent virulence factors, viz, capsule, fimbriae, siderophores, efflux pump, regulatory secretions, and secretory system. As most nosocomial K. pneumoniae infections are MDR/XDR, treatment remains limited. The understanding of the different virulence mechanisms and their genetic control becomes imperative.

Aims and Objective: To determine the prevalence and distribution of virulence genes among Klebsiella pneumoniae isolates.

Materials and Methods: In the present study, virulence genes were analysed with the help of whole-genome sequencing. A total of 41 K. pneumoniae isolates from various nosocomial infections were collected, identified by VITEK 2 and MALDI-TOF-MS, and confirmed by whole genome sequencing. Virulence genes were studied using the Virulence Finder database, a web-based bioinformatics tool that identifies virulence genes in bacterial isolates.

Results: The genes for Type I fimbriae were found in all clinical specimens. Variation was observed in type III fimbriae isolated from bloodstream Infections. Besides the virulence factors seen in Enterobacterales, the K. pneumoniae also possessed virulence factors like enterobactin, aerobactin, salmochelin, and yersiniabactin siderophores. Additional secretory system Types 1 and 3 were detected in our strains, and variation was observed in Type 2.

Conclusion: Our study provides insights into the virulence factors of K. pneumoniae, revealing regional diversity and identifying predominant genes associated with hypervirulent strains. We found type 3 fimbriae genes in most isolates, linked to biofilm formation, and detected MDR nosocomial hypervirulent strains with K2 and K64 capsular types. Notably, the ST395 strain, prevalent in our region, exhibited multiple virulence factors, making it a highly virulent strain.