Abstract
Objective: The aims of the current study were to evaluate the capacity of K. pneumoniae isolated from hospital-acquired urinary tract infection to form biofilm, the relation of this capacity to various virulence genes and the prevalence of Extended Spectrum β-lactamases (ESBL) among these isolates by phenotypic and genotypic methods. Material and Methods: The study included 100 non-duplicate strains of K. pneumoniae isolated from 100 different urine samples from patients with hospital-acquired urinary tract infection. The isolated strains were studied for biofilm formation, ESBL production by phenotypic methods. Molecular studies were applied for the detection of ESβLs genes blaTEM, blaSHV, blaCTX-M and for detection of virulence genes fimH, uge, rmpA, mag A, wzy, kfa and aerobactin genes. Result: The majority of the isolates had the capacity to form a biofilm (81%), with ESBL prevalence rate 41%. The most prevalent gene among ESBL producing K. pneumoniae was blaCTX-M (73.2%) followed by blaSHV (53.6%) and blaTEM (51.2%). Among the virulence genes studied in K. pneumoniae isolates, the most prevalent gene was fimH (76%), uge (70%). There was significant association between ESBL production, and resistance to amikacin, cefepime, ceftazidime, gentamicin, imipenem and meropenem and biofilm production in K. pneumoniae isolates. There was significant association between blaCTX-M, blaSHV, fimH, mag, kfa, wzy, rmpA and aerobactin and biofilm production in K. pneumoniae. Conclusion: The present study highlights the prevalence of virulence genes among biofilm-forming strains of K. pneumoniae isolated from hospital-acquired urinary tract infection. Moreover, there was association between biofilm formation and ESBL production. Further studies are required to elucidate the clinical impact of the association of these different mechanisms.
Highlights
Klebsiella pneumoniae (K. pneumoniae), as a gramnegative bacillus, is known to be associated with various infections such as Urinary Tract Infection (UTI) especially hospital-acquired Catheter-Associated Urinary Tract Infection (CAUTI), sepsis and pneumonia [1, 2].There are many virulence factors in K. pneumoniae associated with its pathogenicity
Among these factors is the capacity of K. pneumoniae to form a biofilm that protects it from the host immune response as well as from the antibiotics [3, 4]
The isolated K. pneumoniae were subjected to antibiotics susceptibility testing by disc diffusion method, determination of ESBL done by combined disc diffusion method and study of biofilm formation by Microtiter plate method
Summary
There are many virulence factors in K. pneumoniae associated with its pathogenicity. Among these factors is the capacity of K. pneumoniae to form a biofilm that protects it from the host immune response as well as from the antibiotics [3, 4]. The formation of biofilm leads to the prolonged persistence of K. pneumoniae on the epithelium and on the medical devices with difficulty in its eradication. There are genes related to biofilm formation in K. pneumoniae such as capsular genes like rmpA gene associated with K1/K2 virulent. Quorum sensing system especially type 2 and pga ABCD operon that regulates the synthesis and translocation of poly-b-1,6-N-acetyl-D-glucosamine adhesin are involved in the biofilm formation through enhancement of cell to cell communication and intercellular adhesion process [8]
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