Spectrum of bacteria associated with diabetic foot ulcer and biofilm formation: A prospective study.

Background: India has the world's largest number of diabetics. Non-traumatic lower limb amputation is the most common devastating complication of diabetes, primarily due to diabetic foot ulcers (DFU) and diabetic foot infections (DFI). In India, the incidence of foot ulcers ranges from 8-17 per cent. DFIs are predominantly polymicrobial and multidrug-resistant (MDR) with the ability to form biofilm, which is an important virulence factor and results in treatment failure.

Aims: The main objectives of the study are to identify the spectrum of multidrug-resistant bacteria associated with these infections, their antibiotic sensitivity pattern, and to detect the biofilm formation.

Methods: This was a prospective study at a tertiary care hospital. One hundred patients over the age of 18, having chronic diabetic foot ulcer, and attending the surgery outpatient department were included. Samples of pus were collected from deep wounds and processed using standard techniques for culture and sensitivity. Biofilm detection was done. Results were compiled and statistically analysed.

Results: One hundred samples were processed and 82 yielded positive cultures. Staphylococcus aureus was the predominant organism, followed by Pseudomonas aeruginosa. Biofilm formation was seen in 38 (46.34 per cent) of the organisms. Biofilms were formed predominantly by Staphylococcus aureus (20 per cent).

Conclusion: The organisms causing chronic diabetic foot ulcers were commonly multidrug-resistant; this was also observed among biofilm formers. Therefore, screening for biofilm formation, along with the usual antibiogram, needs to be performed as a routine procedure in chronic diabetic ulcers to formulate effective treatment strategies for these patients.