Abstract Background: Klebsiella pneumoniae is widely recognized as a prominent opportunistic pathogen that is, commonly associated with both nosocomial and community-acquired illnesses. A notable proportion of K. pneumoniae isolates possess a significant polysaccharide capsule that encompasses the entire bacterial surface, which is widely recognized as a crucial factor contributing to its pathogenicity. Objective: The study was conducted to determine the effect of carbapenem antibiotics on ycfm gene expression a well-known capsule associated gene in carbapenem resistant K. pneumoniae isolates. Materials and Methods: A total of 150 samples obtained from various hospitals in Iraq were cultured on MacConkey agar. Subsequently, differential and selective media to obtain K. pneumonia . The Vitek-2 system was then used to diagnose the results, confirming that 50 isolates were indeed K. pneumoniae . The diagnosed isolates were further subjected to negative staining to validate the presence of a capsule, which was verified to be Klebsiella spp. through molecular analysis utilizing 16S rRNA . The study employed sub-inhibitory quantities of carbapenem antibiotics, specifically meropenem and imipenem, to examine the increase in gene expression of the ycfm gene. Three isolates, including two carbapenem-resistant isolates and one sensitive isolate, were chosen for comparison before and after treatment. Results: From total of 150 clinical samples, 50 isolates were identified as belonging to the K. pneumoniae species. Out of the 50 verified isolates, 25 were confirmed to be producers of capsules. The 16S rRNA identified the 25 isolates as K. pneumoniae using molecular techniques. The microbroth dilution approach yielded a result of 3.9 for the resistant isolates and 1.9 for the sensitive isolate when using carbapenem antibiotics. The one-step quantitative reverse transcription polymerase chain reaction (RT-qPCR) technique identified a change in the gene expression of the capsule gene, with meropenem causing an upregulation of the ycfm gene expression in all isolates, whereas imipenem resulted in a downregulation of the ycfm gene expression in all isolates. Conclusion: The gene expression of the capsule-associated gene ycfm was influenced by carbapenem antibiotics in all isolates. The expression of the ycfm gene was decreased in all isolates when treated with imipenem, while it was increased in all isolates when treated with meropenem, regardless of the isolate’s nature. This can be attributed to the fact that the ycfm gene is not responsible for acquiring resistance, but rather it is a stress response gene associated with capsule formation.
Salman et al. (Thu,) studied this question.