Virulence factors associated with hyper virulent Klebsiella pneumoniae isolated from Different Clinical Sources

Klebsiella pneumonia is an opportunity pathogen causing several diseases including sepsis, pneumonia and wound infections. There are two pathotypes of Klebsiella pneumonia: classical K. pneumoniae (cKp) and hypervirulent K. pneumonia (hvkp). In this study, we attempted to discover the extent occurrence of hypervirulent K. pneumoniae strains among patients in Kirkuk city and their virulence factors. A total of 150 samples were collected from different hospitals in Kirkuk city (Kirkuk General Hospital, Azadi Teaching Hospital, Gynecological and Pediatric (Al-Nasr) Hospital and Children Hospital) during the period between November 2021 to June 2022. The age of patients ranged between 20- 60 years with both sexes. The results showed that 23.33% of K. pneumoniae isolates were positive for string test. Similar results were obtained by using sedimentation assay. The capsule of hvKp is a key virulence factor aiding in the bacterial dissemination and infection. For this reason, in current study, the capsular polysaccharide (CPS) was extracted and quantified. The results showed excessive production of capsular polysaccharide as seen in Klebsiella isolates 16,22,23,24,25,26,28 with an amount 49,41,50,74,49,49,73 μg/ml of CPS respectively. Siderophore production was also examined by using M9 minimal salts media. The results revealed that all K. pneumoniae isolates (100%) were able to produce siderophore. In addition, resistance to tellurite was also identified by using tellurite containing selective media and the results showed that 50% of isolates were resistant to tellurite and the remaining 50% were susceptible. A molecular study using conventional PCR revealed that 21 out of 30 isolates (70%) harbored the rmpA gene while the remaining 9 isolates (30%) lacked this gene. The presence of the iucA virulence gene was also detected and found to be present in all the isolates. Additionally, our findings indicated that 7 out of the 30 isolates (23%) were classified as hvkp.