Determination of virulance genes in clinical klebsiella pneumoniae isolates

Klebsiella pneumoniae is a Gram-negative bacterium which has capsule and was found on the mucosal surfaces of mammals and commonly in the environment (soil, water, etc.). In humans, K. pneumoniae colonizes in the gastrointestinal tract and, less frequently, in the nasopharynx, and infects other tissues by entering circulation system. Pathogenic strains of K. pneumoniae have the potential to cause a wide range of infectious diseases, including urinary tract, respiratory tract, and blood infections. This bacterium has also different virulence factors that contribute to its pathogenicity. Capsules which allow them to overcome host defenses, fimbria, lipopolysaccharides (LPS) and siderophores are the most important of these virulence factors. In our study, 24 isolates isolated from clinical samples and identified as K. pneumoniae with Vitek-2 automated system were taken from Kırşehir Ahi Evran University Training and Research Hospital, Medical Microbiology laboratory stocks. The total DNA of the isolates was extracted by the boiling method. The presence of rmpA, magA and wcaG genes related to the capsule formation, uge and wabG genes related to LPS, type I and Type-II fimbria-related fimH and mrkD genes, ureA and allS genes related to nitrogen mechanism, iutA, iroD ybtA and entB genes related to siderophore production and capsule serotypes of the isolates were investigated by PCR using specific primers. In addition, the hypermucoviscosity (hmv) properties of the isolates were phenotypically determined by string test. As a result of the studies, only isolate Kp12 was found to show hmv feature. As a result of the PCRs, wabG and uge genes were detected in all isolates, entB gene in 96% (23/24), mrkD and ureA genes in 87.5% (21/24), ybtA gene in 62.5% (15/ 24), allS gene in 8% (2/24) and rmpA gene in 4% (1/24). However, wcaG, magA, iutA, iroD and fimH genes and capsules were not detected in any isolate. In the infectious agent K.pneumoniae isolates, capsule, LPS structure, adhesins, siderophores and hypermucoviscosity feature form the basis of the pathogenicity of these isolates. Continuous monitoring of antibiotic resistance as well as these virulence factors in the control of infections caused by K. pneumoniae, may help developing new strategies in the prevention, diagnosis, and treatment of infections caused by this bacterium.