Clonal spread of staphylococci among patients with peritonitis associated with continuous ambulatory peritoneal dialysis

Background Peritonitis is the most important complication of continuous amb ulatory peritoneal dialysis (CAPD). Coagulase-negative staphylococci (CNS) are the most common causes of peritonitis, only limited information is avai lable regarding the distribution and epidemiology of different CNS species associated with CAPD peritonitis. Methods. CNS isolated from dialysis effluent from CAPD patients with perito nitis was identified by species and further analyzed with pulsed-field gel electrophoresis (PFGE). Results. A total of 216 microorganisms (206 bacteria and 10 Candida species ) were isolated from 196 consecutive culture-positive CAPD samples obtained from 75 patients. One hundred and twenty-one (56%) isolates represented st aphylococci. The four most frequently isolated staphylococcal species were Staphylococcus epidermidis (70 isolates), Staphylococcus aureus (31 isolate s), Staphylococcus hemolyticus (10 isolates), and Staphylococcus hominis (4 isolates). PFGE analysis revealed the clonal spread among patients of thre e different clones of S. epidermidis and one clone of S. aureus among the i nvestigated patients. Indistinguishable isolates of either S. epidermidis, S. hominis, or S. aureus were also isolated in repeated samples from severa l patients. Conclusion. PFGE is a useful method for the epidemiological evaluation of s taphylococci-associated CAPD infections and should replace older and less a ccurate methods, such as antibiotic sensitivity patterns. We recommend that CNS isolates from patients with CAPD-associated peritonitis should be save d for future investigations and typing, which would aid in the management o f this patient category.