Frequency of and virulence genes in drug resistant clinical isolates of and their role in biofilm formation.

OBJECTIVES

has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of and genes in biofilm formation by . to understand how this pathogen persists in the hospital environment.

MATERIALS AND METHODS

The antibiotic resistance profile and biofilm-forming ability of one hundred clinical isolates of was evaluated by disc diffusion and crystal-violet staining methods, respectively. Isolates were tested for the presence of and genes.

RESULTS

The isolates were highly resistant to cefepime, third-generation cephalosporins, ciprofloxacin, cotrimoxazole, aminoglycosides and carbapenems. Moreover, four isolates were resistant to colistin. Quantification of biofilm showed that 43% of the isolates were strong biofilm-producer. Furthermore, 32% of the isolates exhibited moderate biofilm-formation and showed initial binding activity. Frequency of and were determined 92% and 36%, respectively.

CONCLUSION

There was strong association between the presence of gene and biofilm formation by isolates (=0.003). In addition, multidrug resistant isolates produced stronger biofilm than other isolates (=0.0001). These results indicate importance of biofilm in resistance of isolates and effect of presence of gene in biofilm formation by strains.