Klebsiella: An insight into the virulence factors and antimicrobial susceptibility pattern

Introduction: Klebsiella pneumoniae is a frequent pathogen isolated from pneumonia, urinary tract infections, liver abscesses, wound infections, intravascular catheter infections, biliary tract infections, peritonitis and meningitis. The increasing occurrence of serious Klebsiella infections necessitates the need to identify the pathogenic mechanisms that are responsible for high virulence of these strains. Objectives: Characterization, detection of virulence factors (Hypermucoviscosity, serum resistance, biofilm formation) and determination of antimicrobial susceptibility pattern of Klebsiella isolates from various clinical samples. Materials and Method: Klebsiella isolates from various clinical samples were analysed in comparison to isolates from stool samples as controls. The isolates were identified by standard microbiological techniques and their antibiogram was determined by Kirby-Bauer disc diffusion method. Biofilm production was determined by tissue culture plate method, hypermucoviscosity by string test and serum resistance by serum bactericidal assay. Results: Amongst the clinical samples, Klebsiella pneumoniae subsp aerogenes(89%) was the predominant species followed by Klebsiella oxytoca (8%) and Klebsiella pneumoniae subsp pneumoniae(3%). The stool samples exhibited a similar pattern with Klebsiella pneumoniae subsp aerogenes (86%) being the predominant species followed by K.oxytoca(14%). The antibiotic susceptibility profile of the isolates showed sensitivity to imipenem, aminoglycosides and fluoroquinolones. Hypermucoviscosity was shown by 12%, serum resistance by 41% and biofilm formation by 36% in clinical isolates. In contrast, hypermucoviscosity, serum resistance and biofilm production was observed in 6%, 7% and 16% of the control isolates respectively. Conclusion: The rising incidence of Klebsiella infections obligates an insight into the various virulence factors and drug resistance patterns to pave a way for combating the growing menace of the virulent pathogen.