Biofilm Production in Carbapenem Resistant Isolates from Chronic Wound Infections

Biofilms are communities of microorganisms covered with extracellular polymeric substances. Such biofilm phenotype makes the microorganism resistant to antibiotics and plays a role in wound chronicity. This results in prolonged hospital stays in ICU, greater cost, and increased mortality. Methods: Pus swabs (59) were collected from a tertiary care hospital near Chennai were processed and identified using standard procedure followed by antibiotic susceptibility testing and identification of carbapenem resistance by Modified Hodge test as per CLSI guidelines. The biofilm formation was tested using plastic microtiter plate method. Results: Out of 59 pus swabs, 51 yielded growth with 69 isolates and 8 yielded no growth. Among the 69 isolates, 51 were GNB and 18 were GPC. Biofilm detection was noted in 84.31% (43/51) GNB isolates with 0.1% crystal violet whereas 100% (51/51) showed biofilm positive with 0.1% safranin. About 74.50% (38/51) isolates of GNB were carbapenem resistant by screening with disk diffusion method. Only 24% (6/25) of GNB isolates among Enterobacteriaceae were positive by Modified Hodge test method. Conclusion: The result shows the association of biofilm production among carbapenem resistant isolates obtained from chronic wound infections.