Miniaturized oligonucleotide arrays: a new tool for discriminating colonization from infection due to Staphylococcus aureus in diabetic foot ulcers.
OBJECTIVE
We sought to evaluate the use of oligonucleotide arrays to discriminate colonization from infection due to Staphylococcus aureus in diabetic foot ulcers.


METHODS
We included diabetic patients hospitalized in a diabetic foot department for an episode of foot ulcer. Only patients who had no antibiotic treatment during the previous 6 months were included. At admission, ulcers were classified on clinical examination, according to the Infectious Diseases Society of America system. Seventy-two patients with a culture positive only for S. aureus as the sole pathogen were included. In individuals with a grade 1 ulcer, a second wound bacterial specimen was obtained 1 month later. Using oligonucleotide arrays, S. aureus resistance and virulence genes were compared between grade 1 and grades 2-4 ulcers.


RESULTS
S. aureus was initially isolated from 22 grade 1 and 50 grade 2-4 ulcers: 35 were methicillin resistant and 37 methicillin sensitive. In 20 grade 1 ulcers (92%), no virulence genes were identified, whereas these genes were present in all but 1 grade 2-4 ulcers. During follow-up, the two grade 1 ulcers that were infected with strains carrying virulence genes rapidly deteriorated; the array technology showed unchanged genotype profiles. On the contrary, two grade 1 ulcers healed: the genotype profiles were different from those at inclusion but without appearance of virulence genes.


CONCLUSIONS
The DNA array appears as a promising technique and is easy to perform. Our observational study suggests that it might help distinguish colonized grade 1 from infected grade 2 wounds, predict ulcer outcome, and contribute to a more adequate use of antibiotics.
Sotto
Albert
A
Institut National de la Santé et de la Recherche Médicale, ESPRI 26, Université de Montpellier 1, UFR de Médecine, Avenue Kennedy, 30908 Nîmes Cedex 02, France.
Richard
Jean-Louis
JL
Jourdan
Nathalie
N
Combescure
Christophe
C
Bouziges
Nicole
N
Lavigne
Jean-Philippe
JP
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004269:DNA, Bacterial / Q000235:genetics; D017719:Diabetic Foot / Q000382:microbiology*; D003937:Diagnosis, Differential; D005260:Female; D016523:Foot Ulcer / Q000382:microbiology*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008297:Male; D016106:Methicillin Resistance; D008875:Middle Aged; D008904:Miniaturization; D020411:Oligonucleotide Array Sequence Analysis; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics*
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D006442:Glycated Hemoglobin