OBJECTIVETo explore the distribution and antibiotic resistance of pathogens in lesions of diabetic foot osteomyelitis (DFO) and analyze the risk factors causing osteomyelitis.

METHODSA total of 372 patients with diabetic foot infections hospitalized between January 2011 and December 2014, including 203 with osteomyelitis (OM group) and 169 without osteomyelitis (non-OM group), were examined for the distribution and antibiotic resistance profile of the pathogens in the wounds. Logistic regression analysis was used to analyze the risk factors causing osteomyelitis.

RESULTSGram-negative bacteria were the predominant pathogens (53.7%) in the infected wounds in OM group, whereas Gram-positive bacteria were the most frequently found (56.7%) in non-OM group (P=0.001). Among the Gram-positive bacteria, Staphylococcus was the dominating flora (35.1%). The resistance rate to oxacillin and cefoxitin of the isolated bacteria in OM group (64.9% and 68.5%, respectively) was significantly higher than that in non-OM group (29.2% and 32.6%, respectively; P<0.05). Among the gram-negative bacteria, Enterobacteriaceae was the dominating flora (62.4%), with a higher resistance rate to Cefepime and Aztreonam in OM group (30.1% and 38.6%, respectively) than in non-OM group (15.1% and 22.2%, respectively; P<0.05). Logistic regression analysis indicated that the infection by multi-drug resistant bacteria and an wounds area >4 cm(2) were the risk factors for osteomyelitis in patients with diabetic foot infections (P<0.05).

CONCLUSIONIn addition to an empirical anti-infection therapy, clinicians should choose specific antibiotics against Gram-negative bacteria according to the microbial spectrum and antibiotic resistance of pathogens in patients with DFO; patients with diabetic foot infections by multi-drug resistant bacteria and those with a wound area exceeding 4 cm(2) are exposed to an increased risk of osteomyelitis.