Pathogens Causing Diabetic Foot Infection and the Reliability of the Superficial Culture

Surg Infect (Larchmt). 2020 Aug 3. doi: 10.1089/sur.2020.072. Online ahead of print.

Abstract

Background: Diabetic foot infection (DFI) is a severe complication of diabetes and a leading cause of hospitalization in the population with diabetes. Empirical intravenous antibiotic agents are initiated according to guidelines based on previously published data on typical pathogens. Therefore, regular evaluation of the pathogens in DFI and their resistance is important to validate current therapies. We evaluated the most current data on bacterial cultures in patients treated at our hospital for DFI and the resistance to the most common antibiotic agents, as well as the reliability of superficial cultures compared with deep tissue cultures. Patients and Methods: This retrospective study was performed at the University Hospital of Tampere and comprised 325 patients with 405 hospitalizations for DFI during the years 2010-2014. Results: The most frequent pathogens in superficial and deep samples were Staphylococcus aureus (36.9%), gram-negative bacilli (24.6%), and β-hemolytic streptococci (BHS, 19.5%). Septicemia was caused most often by Staphylococcus aureus and BHS (34.6% each). The specificity of superficial culture was 91.8%-92.8% and sensitivity 66.7%-87.5%. Conclusions: This study indicates the need to cover Staphylococcus aureus, BHS, and gram-negative bacilli when treating DFI. The reliability of superficial culture was surprisingly good.

Keywords: antibacterial agents; bacteremia; diabetic foot; hospitalization; osteomyelitis; sensitivity and specificity.