Diabetic foot ulcer and multidrug-resistant organisms: risk factors and impact

The primary objective was to characterize factors allowing the colonization of diabetic foot wounds by multidrug-resistant organisms (MDRO), and the secondary objective was to evaluate the influence of MDRO colonization/infection on wound healing.

In 180 patients admitted to a specialized diabetic foot unit, microbiological specimens were taken on admission. Potential risk factors for MDRO-positive specimens were examined using univariate and multivariate analyses. Prospective follow-up data from 75 patients were used to evaluate the influence of MDRO colonization/infection on time to healing.

Eighteen per cent of admission specimens were positive for MDRO. MDRO-positive status was not associated with patient characteristics (age, sex, type of diabetes, complications of diabetes), wound duration, or wound type (neuropathic or ischaemic). In the multivariate analysis, the only factors significantly associated with positive MDRO status on admission were a history of previous hospitalization for the same wound (21/32 compared with 48/148; P = 0.0008) or the presence of osteomyelitis (22/32 compared with 71/148; P = 0.025). In the longitudinal study of 75 wounds, MDRO-positive status on admission or during follow-up (6 months at least or until healing, mean 9 +/- 7 months) was not associated with time to healing (P = 0.71).

MDROs are often present in severe diabetic foot wounds. About one-third of patients with a history of previous hospitalization for the same wound, and 25% of patients with osteomyelitis, had MDRO-positive specimens. This suggests that hygiene measures, or isolation precautions in the case of admission of patients presenting with these characteristics, should be aggressively implemented to prevent cross-transmission. Positive MDRO status is not associated with a longer time to healing.