Distinguishing Colonization From Infection With Staphylococcus aureus in Diabetic Foot Ulcers With Miniaturized Oligonucleotide Arrays

Abstract

OBJECTIVETo extend our previous work on evaluating the use of oligonucleotide arrays to discriminate colonization from infection owing to Staphylococcus aureus in diabetic foot ulcers (DFUs).RESEARCH DESIGN AND METHODSPatients admitted to 14 French diabetic foot departments for a DFU were screened for entry into the study. At admission, ulcers were classified based on clinical examination according to the Infectious Diseases Society of America system. Only patients with monomicrobial culture for S. aureus were included. In persons with an uninfected ulcer, a second wound bacterial specimen was obtained 1 month later. Using oligonucleotide arrays, S. aureus resistance and virulence genes were determined, and each isolate was affiliated to a clonal complex (CC).RESULTSS. aureus was initially isolated from 75 uninfected and 120 infected ulcers; 35 were methicillin resistant. A total of 44 (59%) strains from uninfected DFUs belonged to CC5/CC8 clones vs. 6 (5%) from infected DFUs (P < 0.001). During follow-up, 57 (76%) of uninfected DFUs healed or had a favorable outcome; the strain in 49 (86%) of them belonged to CC5/CC8. Conversely, 18 (24%) had a poor outcome but not a single strain belonged to CC5/CC8 clone. Moreover, lukDE was significantly associated with a favorable outcome of the wound.CONCLUSIONSAs suggested by our previous study, the use of DNA arrays appears to be a promising technique that might help distinguishing uninfected from infected wounds, predicting ulcer outcome and then contributing to a more adequate use of antibiotics.

Distribution of edin in Staphylococcus aureus isolated from diabetic foot ulcers

“…A previous multicentre study conducted on clinical isolates of S. aureus had suggested that two clonal complexes (CC) and an array of virulence factors can be used to discriminate uninfected from infected diabetic foot ulcers (DFUs) . Indeed, we determined that colonizing S. aureus strains (grade 1) with a favourable outcome are linked to the clonal complexes CC5/CC8.…”

Procalcitonin and proinflammatory parameters in diabetic foot infection as new predictive factor

“…The most widely recognized classification is the Wagner system, which grades ulcers from 0 to 5 based largely on ulcer depth and severity [10,11]. The severity of diabetic foot infections ranges from mild and self-limited to limb-and even life threatening [12,13]. Infection characterizes the presence of an inflammatory response and tissue injury as a result of host interaction with multiplying bacteria [11].…”

Diagnosis of infection in the foot in diabetes: a systematic review

“…and the results of the recent Concordance in Diabetic Foot Ulcer Infection (CODIFI) study demonstrate the greater accuracy of tissue compared with swab specimens, 50 the findings of the Ottolino-Perry et al's 62 study are mitigated by the fact that there is no widely accepted or validated definition of "wound bioburden." The detection of pathogenic virulencegenes is an interesting avenue of research that may help differentiate colonizers from pathogens, but studies to date have only included monomicrobial Staphylococcus aureus DFIs [65][66][67]. Although we lack evidence, we believe that new molecular real-time bacterial identification (including determination of virulence genes and antibiotic resistance profiles) may overcome the delay in obtaining culture results and help clinicians administer earlier and more appropriate antibiotic therapy, especially for severe infections.…”