Identification of Capsular Serotypes K1 and K2 in Clinical Isolates of Klebsiella Pneumoniae in North of Iran

ABSTRACT          Background and Objectives: Klebsiella pneumoniae is one of the most important nosocomial pathogens. Its capsular polysaccharide is considered as the first and most important virulence factor of this bacterium. This study aimed to investigate the presence of capsular serotypes K1 and K2 in K. pneumoniae isolates to examine the virulence potency of the isolates.          Methods: Overall, 65 capsulated K. pneumoniae isolates were collected from patients with urinary tract infections in Rasht, Iran. The isolates were examined using biochemical tests and CPS gene amplification using PCR. Mucoid phenotype of the isolates was determined by the string test. The presence of K1 and K2 genes was evaluated by PCR using specific primers for the genes.          Results: Of 65 K. pneumoniae isolates, seven (10.77%) were positive for the presence of the K1 gene and four (6.15%) were positive for the presence of the K2 gene. In addition, six serotype K1 isolates (27.27%), four serotype K2 isolates (18.18%), and 12 non-K1/K2 serotype isolates (54.54%) had hypermucoviscosity phenotypes.           Conclusion: Our results confirm the presence of the capsular serotypes in K. pneumoniae isolates, with a relatively high prevalence for the capsular serotype K1. This study clarifies the importance of rapid diagnosis and suitable treatment of infections caused by K. pneumoniae in prevention of complicated infections.          Keywords: Klebsiella pneumoniae, Virulence factors, Capsular polysaccharide.