The relationship between biofilm formation and presence of fimH and mrkD genes among E. coli and K. pneumoniae isolated from patients in Mosul

Basima Ahmad Abdullah ,Mohammed T. Mahmood

doi:10.33899/mjn.2015.160018

Abstract

Background and objectives: Biofilms have a major medical significance as they decrease susceptibility to antimicrobial agents. The decreased susceptibility to microbial agents within a biofilm arises from multiple factors, including physical impairment of diffusion of antimicrobial agents, reduced bacterial growth rates, and local alterations of the microor-ganisms (M.O) that may impair activity of the antimicrobial agent. The aim of the study was to investigate the biofilm formation among coliforms and study the relationship between biofilm formation and the presence of fimH and mrkD genes among E. coli and K. pneumonia isolates respectively . Materials and method: One hundred and seventy three clinical samples were collected from both gender who visited or admitted to AL- Salam General Teaching Hospital and AL- Wafa’a center for diabetic patients in Mosul city from April 2013 to February 2014, (110) urine samples from patients suffering from urinary tract infections (UTIs) and (63 ) from patients with diabetic foot infections (DFIs). All samples were cultured on selective media as MacConkey and blood agar aerobically. Coliform isolates are identified to species level depending on biochemical and physiological tests and using Rapid ™ ONE panel kit to be conformed to the diagnosis. The ability of coliforms spp. for biofilm formation was assessed using qualitative and quantitative assay. The Congo red agar (CRA) method was used in the qualitative biofilm assay. Results: Out of (85) bacterial spp. , 44(51.8%) species were biofilm producers. The tissue culture plate (TCP) method was used in the quantitative biofilm formation assay. The results showed that 46(54.1%) spp. produced biofilm strongly. All biofilm producing E. coli and K. pneumoniae spp. which gives strong biofilm formation by CRA method and non-biofilm producer spp. were subjected to PCR for determining the relation between biofilm formation and the presence of fimH gene in E. coli isolates and mrkD gene in K. pneumoniae isolates. The results revealed that all biofilm producing E. coli 15(100%) isolated from UTI samples were positive for fimH gene. While all biofilm producing K. pneumoniae 9(100%) and 5(100%) isolated from UTIs and DFIs respectively were positive for mrkD gene.

Highlights

Infection caused by pathogenic E. coli and other coliforms spp. are often initiated by binding of the bacteria to the host cell surface via specific bacterial adhesins with fimbriae
The tissue culture plate (TCP) method was used in the quantitative biofilm formation assay
The results revealed that all biofilm producing E. coli 15(100%) isolated from

Summary

Introduction

Infection caused by pathogenic E. coli and other coliforms spp. are often initiated by binding of the bacteria to the host cell surface via specific bacterial adhesins with fimbriae. Fimbrial adhesins are thread-like structures that reach out from the bacterial surface enabling bacteria to adhere to host cells ( Heydari et al, 2013 ). Type 3 fimbrial adhesins are able to mediate the binding of K. pneumonia to various human cells , such as endothelial cells , epithelial cells of the respiratory tract and urinary tract. The decreased susceptibility to microbial agents within a biofilm arises from multiple factors, including physical impairment of diffusion of antimicrobial agents, reduced bacterial growth rates, and local alterations of the microorganisms (M.O) that may impair activity of the antimicrobial agent. The aim of the study was to investigate the biofilm formation among coliforms and study the relationship between biofilm formation and the presence of fimH and mrkD genes among E. coli and K. pneumonia isolates respectively

Objectives

Methods

Results