In vitro bacteriologic study and empiric antibiotic regimens for diabetic foot ulcers

Hundred diabetic patients were admitted with clinically infected foot ulcers and were studied during the period of 1st January 2010 to 30th June 2011. Pus samples of bacterial culture were collected from 30 patients admitted with diabetic foot infection. Antimicrobial susceptibility testing of aerobic isolates was performed by the standard disc diffusion method as recommended by National Committee for the Clinical Laboratory Standards. Micro broth dilution test was arranged for susceptibility of anaerobic organisms to metronidazole and amoxicillin/clavulanate. A vencomycine screen agar (6 µg/ ml) was used to detect vencomycine intermediate isolates of Staphylococci. Clinical grading and bacteriological study of 100 patients revealed, 69 (69.0%) patients had Gram-negative organisms and Pseudomonas aeruginosa was the most common, while 21 (21.0%) patients had Gram-positive organisms and Staphylococci was the most common. Infection with anaerobic was found in one patient (1.0%). Both Gram-positive and –negative organisms were seen in 9 patients (9.0%). P. aeruginosa and Staphylococcus aureus exhibited a high frequency of resistance to the antibiotics tested. All the isolates were uniformly susceptible to fosfomycine, levofloxacin, amikacin and vencomycine. In this study P. aeruginosa, S. aureus, Escherichia coli, S. epidermidis and Proteus were the most common causes of diabetic foot infections. The rate of antibiotic resistance was 61.86% among the isolates. All the isolates were uniformly susceptible to fosfomycine, levofloxacine, amikacin and vencomycine.