Investigation of biofilm formation, effect of antibiotics on biofilms and the meca gene in staphylococcus strains isolated from catheter samples

The most important complication of frequently used catheters in hospitals is the risk of developing infections. Staphylococci which are one of the most common causes of catheter-related infections, are able to colonize catheters by their biofilm-forming potential, also protecting them from host defense and antibiotics. In our study, 62 Staphylococcus strains, isolated from the catheter samples sent to Balcalı Hospital Central Laboratory of Çukurova University Faculty of Medicine were aimed to investigate the biofilm forming properties, the effect of antibiotics on biofilms and the mecA gene responsible for methicillin resistance. Antibiotic susceptibility tests of isolates were performed with the Vitek2 compact system, and oxacillin, vancomycin and daptomycin MIC values were determined by broth microdilution test. Biofilm properties and Minimum Biofilm Eradication Concentration (MBEC) values of strains were determined by microplate method. As a result of our study, MIC50 and MIC90 values of oxacillin, vancomycin and daptomycin were determined as 32 /> 128, 1/2 and 0.25 /1 μg/ml respectively. . Of the 62 staphylococci, 34 (54.8%) were determined biofilm positive (BP). 23.5% of BP strains showed weak (+), 32.4% moderate (++) and 44.1% strong (+++) biofilm properties. The MBEC50 and MBEC90 values of oxacillin, vancomycin and daptomycin were determined as 64 /> 128, 128/128 and 4 />32 μg/ml respectively. The presence of the mecA gene in the strains was investigated by Real-time PCR method. 90.3% of the strains were determined as carrier of the MecA gene. It was thought that findings of our study may guide understanding biofilm infections and more rational orientation of treatment.