Evaluation of Drug Resistance Before and After Biofilm Formation of Bacteria Causing Wound Infection and Detection of Their Protease Activity

Abstract

Background: Wound infection is a highly common problem in hospital settings, where microbes are often resistant and difficult to treat due to rapid exposure to antibiotics. While treating wound infection, bacteria often enter the deep tissue; as therapy needs long exposure time, bacteria have sufficient time to develop biofilm, which makes them much more resistant to antibiotics. Objectives: The current study was performed to identify wound-infecting bacteria and determine their protease production activity. Methods: The ability to produce biofilm was evaluated by the Congo red agar and tube methods. Antibiotic resistance pattern was assessed before and after biofilm formation to detect the changes in resistance due to biofilm formation. Results: We identified Pseudomonas aeruginosa, Proteus mirabilis, Proteus vulgaris, Corynebacterium xerosis, Alcaligenes faecalis, Bacillus cereus, Escherichia coli, Acinetobacter spp., Klebsiella pneumoniae, Staphylococcus spp., Shigella spp., and Salmonella spp. in 20 wound samples, among which about 10 isolates were found to be biofilm producers. Almost all the biofilm producers showed complete resistance or a much smaller inhibition zone. Conclusions: Pathogenic bacteria can be more difficult to eradicate by antibiotic treatment if they are able to produce biofilm; thus, it is essential to prevent biofilm formation.