Microbial profile of diabetic foot infections in Trinidad and Tobago

To examine the microbiologic profile of diabetic foot infections in order to guide empiric antibiotic choices.

All patients with moderate-severe diabetic foot infections at a tertiary care facility were identified from July 2011 to June 2012. Culture samples were routinely collected before empiric antibiotics were commenced. Retrospective chart review was performed to extract the following data: demographics, clinical details, empiric antibiotic choice and microbiologic data. Descriptive analyses were performed using SPSS 12.0.

There were 139 patients at a mean age of 56.9 ± 12.4 years. Mixed poly-microbial infections were present in 56.8% of cases. Of 221 organisms isolated, 64.7% were gram-negative aerobes, 32.1% were gram-positive aerobes and 3.2% were obligate anaerobes. Multidrug resistant organisms were encountered in 25.9% of cases and included ESBL producers (11.3%), MRSA (4.5%) and VRE (1.4%). Both ciprofloxacin and ceftazidime had good overall anti-microbial activity against gram-negative (68% and 62%, respectively) and gram-positive pathogens (69% and 48%, respectively). Obligate anaerobes were uncommonly isolated due to institutional constraints.

In this environment, both ciprofloxacin and ceftazidime provide good broad-spectrum anti-microbial activity against the commonly isolated pathogens. Either agent can be used as single agent empiric therapy in patients with moderate/severe diabetic infections in our setting. Although institutional limitations precluded isolation of anaerobes in most cases, there is sufficient evidence for anti-anaerobic agents to be recommended as a part of empiric therapy.