Bacterial spectrum in surgical wound infection, its susceptibility pattern and biofilm formation among isolates

Topic: Bacterial spectrum in surgical wound infection, its susceptibility pattern and biofilm formation among isolates. Aim: To identify the spectrum of bacterias associated with wound infection and their antimicrobial susceptibility pattern and biofilm formation. Introduction: Chronic wounds are severe worldwide problem. Wounds are considered chronic when healing fails to proceed normally and anatomic and functional integrity of the skin is not achieved in approximately 1 month. Chronic wound include diabetic foot ulcer, pressure or decubitus ulcer, venous leg ulcer and non-healing surgical site infection.1Annual incidence is of diabetic ulcer in India in a population based study is 1.0 to 4.1% 1. Biofilm formation is widespread in chronic wounds. The biofilm phenotype gives rise to drug resistant strains resulting in treatment failure. Materials and Methods: A prospective study was done at a tertiary care Hospital in North Karnataka for a period of 1 year from February 2017 to January 2018. A total of 241 samples in an age group of 20 to 70 years with history of wound infection attending surgery department were collected with a sterile cotton swab and processed as per CLSI standards.2 Detection of biofilm formation by modified congo red agar method, tissue culture plate method and tube assay method. Results: A total of 241 pus samples were collected. 65.56% (158) showed bacterial growth and 34.43% (83) showed no growth. The study group comprised 139 male and 102 female patients in the ratio of 1.39:1. Age range was 20-70 years Maximum samples were in the age group of 21-30 years. 44.93% (71) of isolates were obtained Gram positive organisms and 55.06 % (87) were Gram negative. Escherichia coli was the predominant isolated organism 16.18% (39). Followed by staphylococcus aureus 9.54% (23). 76 out of 158 sample showed biofilm formation (48.01%). Staphylococcus aureus was dominant biofilm former. 81.57% (62) of biofilm producers were multiple drugs resistant. Conclusion: Detection of biofilm formation is an easy and cost effective test that can be performed routinely in the lab. Biofilm will help surgeon to effectively manage these infections riding more aggressive source control and appropriate antibiotics resulting in decrease mortality and morbidity of patients. References: Reiber, GE. Epidemiology of foot ulcers and amputations in the diabetic foot. In: Bowker, JH.; Pfeifer, MA., editors. Levin and O'Neal's the diabetic foot. 6th ed. St Louis: Mosby; 2001.p. 13-32.