Biofilm formation and Antibiotic susceptibility pattern among Staphylococcus aureus in a tertiary care hospital in Kanchipuram: An Evaluation of screening methods for biofilm formation

The ability of Staphylococcus aureus to form biofilms is of significant clinical interest, as biofilm development impacts the efficacy of antimicrobial therapy and the subsequent outcome of an infection. The present study is undertaken to detect the biofilm production and to determine the antibiotic susceptibility pattern among the Staphylococcus aureus isolates. A total of 100 Staphylococcus aureus isolated for the first time from pus, blood, catheter, IV cannulas were included in the study. Biofilm detection was done by tube method and Microtitre plate method. Antibiotic susceptibility was done by Kirby bauer disc diffusion method. Methicillin resistance was detected by Cefoxitin disc diffusion method. By tube method and Microtitre plate method 26% and 46% of the isolates were identified as biofilm producers. By Microtitre plate method, BHI broth (Brain heart infusion broth) and BHI broth with sucrose was used and the difference in the biofilm forming ability was compared. When BHI broth with sucrose was used 69% showed biofilm formation whereas when tested with BHI broth, only 46% were identified as biofilm producers. Good sensitivity was observed for Amikacin (88%) and cefotaxime (82%). MRSA (Methicillin resistant Staphylococcus aureus ) was detected among 19% of the isolates. Among the biofilm producers if there are drug resistant bacteria like MRSA the problem becomes challenging and requires combination of several antibiotics. Hence Screening for biofilm production by bacterial isolates should be performed. Infection control program should address the effective execution of disinfection procedures.