Study of Biofilm Formation Among Clinical Staphylococcal Isolates

Abstract

Introduction: Biofilm forming microorganisms are related to chronic and recurrent human infections as well as are highly resistant to antimicrobial agents. Various methods have been used in medical field for the detection of biofilm production which includes visual assessment by electron microscopy and polymerase chain reaction, quantitative method like Tissue Culture Plate (TCP) method and two qualitative methods such as Tube Method (TM) and Congo Red Agar (CRA) method. Objectives: To detect the prevalence of biofilm formation in Staphylococci, to evaluate two different methods i.e. TM and CRA for the detection of biofilms and to see its relation with antimicrobial resistance. Materials and Method: The study was conducted at Department of Microbiology, Dr. D.Y. Patil Hospital and Research Centre during the period June 2011 to June 2013. A total of 130 clinical isolates were subjected to biofilm detection methods. Standard microbiological procedure was done to identify the isolates. Biofilm detection was tested by TM and CRA. Kirby-Bauer disc diffusion technique was performed to do antibiotic susceptibility test of biofilm producing bacteria according to CLSI guidelines. Results: From the total of 130 clinical isolates, biofilm productions among Staphylococci were 59.23%. And the percentage of biofilm detection of Staphylococci isolates by Congo red method were 31.54% and by test tube method 50%. Hence, the TM method was considered to be superior to CRA. We have also observed higher antibiotic resistance in biofilm producing bacteria than non-biofilm producers. Conclusion: We can conclude from our study that the TM method is a more suitable and reliable method as compared to CRA and can be recommended as a general screening method in laboratories for detecting biofilm forming bacteria.

Keywords

• antimicrobial resistance
• congo red agar method
• test tube method