ABSTRACT Background The prevalence of carbapenemase (CPE)-producing K. pneumoniae isolates has increased in hospitals worldwide over the past decade. Resistance is often associated with the ability of clinical isolates to form biofilm. The main objective was to investigate biofilm development in 30 hospital isolates of K. pneumoniae with confirmed CPE production as well as to analyze the distribution of resistance genes, the frequency of virulence genes, and their role in the regulation of biofilm. Methods Selected isolates of K. pneumoniae with CPE production were examined for their ability to form biofilms using crystal violet staining. The presence of resistance genes ( blaSHV1 , blaTEM1 , blaCTXM1 ) and genes ( fimH, mrkD, entB ) associated with biofilm formation was confirmed by PCR. Quantitative real-time PCR was then performed to compare the expression of biofilm-associated genes in weak, moderate and strong biofilm formers among K. pneumoniae . Results More than 50% of all K. pneumoniae isolates were confirmed to be strong biofilm producers. PCR confirmed the presence of resistance-associated genes and genes important for biofilm development in all clinical isolates tested. Additionally, qPCR showed increased regulation of the adhesion-related genes fimH and mrkD in moderate or strong biofilm formers of K. pneumoniae compared to weak biofilm formers. Conclusions The present results provide valuable information on the relationship between increased CPE resistance, biofilm production, and its genetic regulation in K. pneumoniae hospital isolates.
Dekkerová et al. (2026) studied this question.