Detection of magA Gene in Klebsiella spp. Isolated from Clinical Samples

Klebsiella infections are caused mainly by K. pneumoniae and K. oxytoca. In the last two decades, a new type of invasive Klebsiella pneumoniae which contains mucoviscosity-associated gene (magA) has emerged. The aim of this study was to investigate the prevalence of magA gene and to detect antimicrobial susceptibility patterns of Klebsiella spp. isolated from clinical samples. Klebsiella isolates were collected from patients admitted to referral hospitals of Hamadan, Iran, during a 12-month period from 2007 to 2008. The samples were analyzed by conventional microbiological methods and polymerase chain reaction (PCR). The hypermucoviscosity (HV) phenotype of Klebsiella isolates was characterized by formation of viscous strings >5 mm as a positive test. The susceptibility of isolates to routine antibiotics was assessed by agar disk diffusion method. Out of 105 Klebsiella isolates, 96.2% was identified as K. pneumoniae and 3.8% as K. oxytoca by PCR. magA gene was detected in 4 (3.8%) isolates of K. pneumoniae. The isolates of K. oxytoca contained no magA gene. From 4 isolates with positive magA gene, two of them were HV+ and two were HV- phenotype. Overall, sixty-four isolates (60.95%) of K. pneumoniae showed an HV positive phenotype and all isolates of K. oxytoca were HV-phenotype. The most effective antibiotics against the isolates were tobramycin (79.05%), ceftazidime (79.05%), ceftizoxime (78.09%), ciprofloxacin (76.19%), ceftriaxone (76.24%) and amikacin (74.29%). The results suggest that there is also magA associated serotype of the K. pneumoniae in this region. In addition, the presence of HV+ phenotype may not be associated with magA.