Role of the Staphylococcus epidermidis slime layer in experimental tunnel tract infections.
An experimental animal model was used to assess the slime layer of Staphylococcus epidermidis as a pathogenic factor in tunnel tract infections. Mice were inoculated with high-slime-producing or non-slime-producing strains of S. epidermidis, either along the length of a subcutaneous catheter or in the area where a catheter had been placed and immediately removed (controls). Among the catheter-bearing mice, the phenotypically distinct staphylococci produced similar, high frequencies of abscess formation (72% [44 of 61] versus 81% [31 of 38]; P = 0.29). In controls, the non-slime-producing organisms were significantly more pathogenic (87% [40 of 46] versus 57% [25 of 44] abscess formation; P = 0.001). No consistent difference was detected between blood isolates obtained from patients with central venous catheter bacteremia and those from neonates with bacteremia in the absence of a prosthetic medical device. Quantitative culture of removed catheters showed greater adherence by the slime-producing isolates (P = 0.014). In this mouse model, slime production by S. epidermidis did not increase the risk of catheter tunnel tract infection, despite the greater catheter adherence of the slime-producing organisms. These findings suggest that traumatized tissue may be a sufficient condition for the development of S. epidermidis catheter-associated infections.
Patrick
C C
CC
Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee.
Plaunt
M R
MR
Hetherington
S V
SV
May
S M
SM
D000038:Abscess / Q000209:etiology*; D000818:Animals; D002405:Catheterization, Central Venous / Q000009:adverse effects; D004195:Disease Models, Animal; D051379:Mice; D013203:Staphylococcal Infections; D013212:Staphylococcus epidermidis / Q000472:pathogenicity*; D013530:Surgical Wound Infection