Detection of biofilm production and its impact on antibiotic resistance profile of bacterial isolates from chronic wound infections

Abstract

Background: Microorganisms are known to be involved in the formation of biofilm. These biofilms are often seen in chronic wound infections, surgical site infections, implants etc., These are capable of causing recalcitrant infections and most of them are also known to possess high antibiotic resistance. Objectives: This study was conducted to detect the biofilm formation in bacterial isolates from chronic wound infections. Materials and Methods: In the present study, ninety two isolates from chronic wound infections were identified by MALDI-TOF-MS (bioMerieux) and VITEK-2-MS (bioMerieux). These isolates were further screened for biofilm formation by three methods i. e., Tissue Culture Plate method (TCP), Tube Method (TM) and Congo Red Agar (CRA) method. Impact of biofilm production was correlated with the antibiotic resistant pattern. Statistical Analysis: Statistical analysis was done for all three methods considering TCP as Gold Standard and parameters like senitivity and specificity of TM i.e. 47.2 and 100% respectively. Results: Out of 92 isolates, biofilm formation was seen in 72 isolates (78.2%) by TCP method. 64 isolates were strong biofilm producers, 8 isolates were moderate biofilm producers and 20 isolates were nonbiofilm producing. High prevalence of biofilm formation was seen in nonhealing ulcers infected with Staphylococcus aureus followed by Klebsiella pneumoniae. Conclusion: Among three screening methods used for detection of biofilm production, TCP method is considered to be a standard and most reliable for screening of biofilm formation in comparison to TM and CRA.

Keywords

• biofilm screening
• diabetic foot ulcer
• nonhealing ulcer