Kinetics of Staphylococcus epidermidis clearance from the peritoneal catheter site of renal failure mice following intracatheter inoculation.
A mouse model of surgically induced renal failure harboring a peritoneal catheter implant was utilized to study the response to intracatheter (IC) peritoneal inoculation of 10(6) or 10(8) colony-forming units (CFU) Staphylococcus epidermidis. The kinetics of bacterial clearance from peritoneal structures, including the peritoneal catheter implant, was investigated in renal failure and sham-operated mice. All animals survived experimental challenge with 10(6) CFU; however, microbiological assessments conducted 1 week and 1 month after inoculation revealed that the catheter site of a small number of renal failure mice was persistently colonized. During 1 month following 10(8) CFU IC inoculation, significant animal mortality was observed in renal failure mice (29.4%), while sham-operated controls presented minimal lethality (5.9%). In surviving mice of both groups, the peritoneal catheter site proved to be a reservoir for persisting S. epidermidis, a finding confirmed by scanning electron microscopy. Throughout the study, local and systemic inflammatory responses were comparable in sham-operated and renal failure mice. Nevertheless, 3 and 4 weeks after 10(8) CFU inoculation, S. epidermidis recovery was significantly greater in sham-operated controls. Phenotypic colonial variation was observed in a majority of S. epidermidis isolates, and only in those specimens recovered 2 or more weeks after inoculation. Our results reveal that the peritoneal catheter implant provides a preferred site for persistent bacterial colonization up to 1 month after inoculation.
Gallimore
B
B
Department of Medicine, Montreal General Hospital, McGill University, Que., Canada.
Gagnon
R F
RF
Richards
G K
GK
D000818:Animals; D002408:Catheters, Indwelling; D015169:Colony Count, Microbial; D005260:Female; D005500:Follow-Up Studies; D007676:Kidney Failure, Chronic / Q000503:physiopathology* / Q000628:therapy; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008855:Microscopy, Electron, Scanning; D010531:Peritoneal Dialysis, Continuous Ambulatory / Q000295:instrumentation*; D010537:Peritoneum / Q000382:microbiology; D018805:Sepsis / Q000382:microbiology; D013203:Staphylococcal Infections / Q000503:physiopathology; D013212:Staphylococcus epidermidis / Q000502:physiology*; D013499:Surface Properties; D015996:Survival Rate