Bacteriological study of diabetic foot infections

ABSTRACT

INTRODUCTION Foot infections are one of the major complications of diabetes mellitus and a significant risk factor for lower extremity amputation. Providing effective antimicrobial therapy is an important component in treating these infections. This study assesses the microbial isolates of patients with diabetic foot infections and their antibiotic susceptibility pattern. MATERIALS AND METHODS A retrospective study of 75 patients with diabetic foot infections admitted to RIPAS hospital between June 2008 and June 2010 was undertaken. Bacteriological specimens were obtained and processed using standard hospital procedure for microbiological culture and sensitivity testing. RESULTS Overall, 40 (54%) patients had subcutaneous infections, 22 (29%) had infected superficial ulcers, seven (9%) had infected deep ulcers involving muscle tissue and six (8%) had osteomyelitis. A total of 98 pathogens were isolated. Forty percent of the patients had polymicrobial infection, 39 (52%) had single organism and 6 (8%) had no growth. Gram-negative bacteria (67%) were more commonly isolated than gram-positive bacteria (30%). The three most frequently found gram-positive organisms were Staphylococcus aureus (10.2%), Streptococcus pyogenes (7.1%) and Methicillin resistant Staphylococcus aureus [MRSA] (7.1%) and the most common gram-negative organisms were Pseudomonas aeruginosa (19.4%), Klebsiella pneumoniae (15.3%), and Acinetobacter spp. (10.2%). Vancomycin was found to be the most effective against gram-positive bacteria whereas Amikacin was the most effective against gram-negative bacteria based on antibiotic testing. CONCLUSION 40% of diabetic foot infections were polymicrobial. Staphylococcus aureus and Pseudomonas aeruginosa were the most common gram-positive and gram-negative organisms respectively. This study helps us to choose the empirical antibiotics for cases of diabetic foot infections.