Biofilm Formation and Gene Expression in Carbapenem-Resistant Klebsiella pneumoniae OXA-48 Under Different Growth Conditions

Understanding bacterial risk factors, such as biofilm formation and antibiotic resistance, is crucial for treatment. This study investigates biofilm development and gene expression in carbapenem-resistant Klebsiella pneumoniae OXA-48 to understand molecular mechanisms. Two strains of Klebsiella pneumoniae were used in the current study: an environmental strain collected from water samples of army canal in Baghdad, Iraq, identified as a non-resistant strain of K. pneumoniae, and a carbapenem-resistant K. pneumonia OXA-48 (NCTC-13442), which was obtained from the Public Health England culture collection (PHE). Using a tissue culture plate test, biofilms were evaluated under various growth conditions at four different stages of biofilm development: initial attachment (6 hours), microcolony formation (12 hours), maturity (24 hours), and dispersion (48 hours). Genes linked to biofilm development, quorum sensing, and antibiotic resistance were examined for their expression simultaneously using quantitative real-time PCR (qPCR). A significant relation between both biofilm formation phases and carbapenem-resistant Enterobacterales, with the highest biofilm production occurring during the first 24 hours of the maturation stage, also biofilm formation under the studied conditions has a major impact on the diversity of biofilm gene expression quantification studies. The results of the qPCR studies show a correlation between the expression of genes linked to biofilm development and the formation of phenotypic biofilms. These findings show regulation of these genes in significant carbapenem-resistant Enterobacterales pathogens. Also the results showed that the K. pneumoniae OXA-48 CRE strain has a high biofilm formation rate and that genes related to biofilm development are up-regulated during biofilm growth. The findings suggest that the biofilms of this strain successfully adapt to various environmental conditions and play a pathogenic role, linked to multidrug resistance and the successful dissemination of carbapenem-resistant Enterobacterales in common infections.