Human skin flora as a potential source of epidural abscess.
BACKGROUND
The mechanism of epidural infection associated with epidural block is not clearly understood. Resident organisms in skin specimens were studied after skin was prepared with disinfectants.


METHODS
Sixty-nine paired skin specimens were excised at incisional sites after skin disinfection with 10% povidone-iodine (10% PVP-I) or 0.5% chlorhexidine in 80% ethanol (0.5% CHE) from 60 patients having back surgery. One of the specimen pairs was placed in 10 ml brain-heart infusion broth and incubated in air at 37 degrees C for 96 h. The other specimen was sectioned at 3 microns and prepared with Gram's stain for examination with the microscope.


RESULTS
Thirteen gram-positive staphylococcal species (Staphylococcus epidermidis, 69.2%; S. hyicus, 15.4%; and S. capitis, 15.4%) were isolated from cultures. The isolates were found in a significantly greater proportion of the skin specimens disinfected with 10% PVP-I than in those disinfected with 0.5% CHE (11 of 34 cultures [32.4%] vs. 2 of 35 cultures [5.7%]; P < 0.01). Many gram-positive cocci were observed with the microscope in 4 (11.8%) and 5 (14.3%) of 34 and 35 skin specimens disinfected with 10% PVP-I and 0.5% CHE, respectively. The cocci formed a dense colony in each follicle and in the stratum corneum. No organism was present in any of 17,584 sweat glands examined.


CONCLUSIONS
In a large proportion of patients, isolation of viable organisms from excised skin specimens after disinfection with 10% PVP-I suggests that contamination of the epidural space by the skin flora may be a potential mechanism of epidural infection associated with epidural block.
Sato
S
S
Department of Anesthesiology, School of Medicine, Fukuoka University, Japan.
Sakuragi
T
T
Dan
K
K
D000038:Abscess / Q000382:microbiology / Q000517:prevention & control*; D000767:Anesthesia, Epidural / Q000009:adverse effects*; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use*; D001415:Back / Q000601:surgery; D002710:Chlorhexidine / Q000627:therapeutic use*; D000431:Ethanol / Q000627:therapeutic use*; D006801:Humans; D011206:Povidone-Iodine / Q000627:therapeutic use*; D012867:Skin / Q000187:drug effects / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000302:isolation & purification*; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000302:isolation & purification*
D000891:Anti-Infective Agents, Local; D000431:Ethanol; D011206:Povidone-Iodine; D002710:Chlorhexidine