Characterisation of virulence genes associated with pathogenicity in Klebsiella pneumoniae

ABSTRACT

Purpose: This study was undertaken to characterise the virulence factors in clinical strains of Klebsiella pneumoniae and analyse their association with various infections caused and also to determine the association between virulence factors and antimicrobial resistance profile. Materials and Methods: A total number of 370 clinically significant, non-duplicate isolates of K. pneumoniae isolated from both hospitalised patients and patients attending clinics were included in this study. Polymerase chain reaction (PCR) was carried out for the detection of various virulence genes such as mucoviscosity-associated gene A (magA), gene associated with allantoin metabolism (allS), Klebsiella ferric iron uptake(Kfu), capsule-associated gene A (K2A), regulator of mucoid phenotype A (rmpA), enterobactin (entB), yersiniabactin (YbtS), aerobactin, Fimbrial adhesin (FimH) and uridine-diphosphate galacturonate 4-epimerase (uge). Antimicrobial susceptibility testing and PCR-based detection of beta-lactamase-encoding genes such as extended-spectrum beta-lactamases, AmpCs and carbapenemases were performed. Univariate analysis was done to find the association between virulence genes and mortality. Results: The siderophore, entB, was present in most (90.5%) of the isolates. Of the 370 isolates, 345 carried multiple virulence genes; 15 harboured single virulence genes and 10 did not harbour any of the studied virulence genes. The most common combination of occurrence was entB and FimH. A mortality rate of 12.75% (38/298) was observed among hospitalised patients. None of the virulence genes had any significant association with mortality. Conclusion: Pathogenic K. pneumoniae can harbour single to multiple virulence genes. Invasive infection with even a single virulence gene-harbouring K. pneumoniae can lead to poor outcomes. Both multidrug-resistant (MDR) and non-MDR K. pneumoniae can harbour a variety of virulence genes. None of the virulence genes have a significant association with mortality.