Virulence determinants associated with biofilm formation by Klebsiella pneumoniae causing hospital-acquired bloodstream infection

Document Type : Original Article


1 Medical Microbiology and Immunology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt

2 Department of Tropical Medicine, Faculty of Medicine, Zagazig University, Zagazig, Egypt.


Background: Klebsiella pneumoniae (K. pneumoniae) significantly contributes to hospital-acquired bloodstream infections with high morbidity and mortality, especially biofilm-producing strains. It has been noticed that ability to produce biofilm by K. pneumoniae is linked to presence of some virulence genes, but this relationship needs further investigation. This work aimed to investigate ten virulence genes that may contribute to biofilm formation in K. pneumoniae strains causing bloodstream infections. Methods: This cross-sectional study included 108 K. pneumoniae isolates obtained from cases of hospital-acquired bloodstream Infections. The sensitivity to different antibiotics was tested by the disc diffusion method. Ability to form biofilm was detected by the tissue culture plate method. All isolates were tested by PCR to detect ten virulence genes suggested to be linked to biofilm formation ability. Results: The ability of biofilm formation was detected in 55.6% of the studied strains. Biofilm formation was more prevalent among wcaG, fimH, wabG, and mrkD positive isolates in comparison to negative isolates for the same genes. However, only wcaG and fimH genes have been found to be significantly associated with biofilm formation (P < 0.05). Conclusion: The association between the ability to form biofilm and the existence of wcaG and fimH genes in K. pneumoniae bacteremia isolates suggests these genes as promising therapeutic targets.


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