Clinical presentation and bacteriology of diabetic foot ulcers at Mulago Hospital: a prospective case series study

Abstract

Diabetic foot ulcer is a common cause of mortality among patients admitted to Mulago hospital. Pe-ripheral neuropathy and peripheral arterial disease are the major risk factors for diabetic foot ulceration and the severity of these two conditions may determine treatment options and ulcer outcomes. The study assessed the clinical presentation of foot ulcers in diabetic patients and identified then common bacterial isolates from diabetic foot ulcers and their susceptibility patterns. This was a prospective study involving 60 consecutive patients with diabetic foot ulcers admitted to the endocrinology unit at Mulago hospital between July and December 2010. Patients were recruited after the provision of written informed consent. Deep tissue swabs from the ulcers were then taken at debridement for both aerobic and anaerobic cultures and susceptibility tests using standardmicrobiological methods.Results:Of the 60 patients, 57% had neuroischemic foot ulcers, 18% had neuropathic ulcers, 18% had is-chemic ulcers and 7% had unclassified ulcers. 98.3% of the samples grew 93 aerobic bacteria and noanaerobe was isolated. Polymicrobial infection occurred in 41% of samples of which 10% had mixedgrowth. 80.6% of the isolates were Gram-negative aerobes, mainly E.coli Klebsiella, Pseudomonas, and Proteus while eighteen (19.4%) were Gram-positive, mainly Staphylococcus aureus and Entero-coccus faecalis. The prevalence of MuMultidrug-resistant organisms (MDRO) was 84% and Methicillin-resistant staphylococcus aureus (MRSA) was 60% while Extended-spectrum beta-lactamases (ESBL)was 43.5%. Diabetic foot ulcers were mostly neuroischemic with moderate neuropathy severity. Infection was mostly due to aerobic Gram-negative organisms with a high prevalence of MDRO, ESBL, and MRSA. Most isolates were susceptible to vancomycin, imipenem, and ciprofloxacin. Deep tissue culture and sensitivity tests should be done to make appropriate antibiotic choices for diabetic patients with foot ulcers.