Infectious consequences of continuous ambulatory peritoneal dialysis

Oral versus Intraperitoneal Application of Clindamycin in Tunnel Infections: A Prospective, Randomized Study in Capd Patients

Objective

To evaluate the potential superiority of either oral or intraperitoneal treatment of catheter tunnel infections (TI), using clindamycin as a first-Iine antibiotic and ultrasound as a diagnostic tool.

Design

This was a prospective, randomized study in continuous ambulatory peritoneal dialysis patients. From August 1993 until August 1995, 16 clinically and ultrasound-proven episodes of TI were randomly assigned to either an oral or an intraperitoneal (IP) treatment (100 patients, 1414 patient-months). Main criteria for TI diagnosis were purulent drainage from the exit site and/or a positive ultrasound (pericatheter fluid collection of at least 2 mm, 7.5 MHz transducer). Initially, clindamycin (20 mg/kg body weight) was given via the oral (three times per day) or intraperitoneal route (four times per day). In the case of incompatibility or resistance to clindamycin, either oxacillin orciprofloxacin were used orally or IP.

Results

Based on ultrasound criteria, the mean time until a ≥50% reduction of pericatheter abscess diameter was 26 days (median) (range: 8 28 days) in the oral, and 15 days (8 27 days) in the IP group (p ≤ 0.05). Showing no significant difference of pericatheter fluid at study entry with 4 mm (median) (range: 2 -6 mm) in the oral group and 4 mm (2 -4 mm) in the IP group, the IP treatment resulted in a decrease to 0 mm (0 2 mm) after 28 days (p < 0.05), while the diameter was still 2 mm (0 10 mm) (NS) in the oral group. Disappearance of exit-site infection was also somewhat earlier in the intraperitoneal group (51 vs 15 days, NS). Catheter removal had to be done once in the IP group and twice in the oral group within 6 months after study entry.

Conclusions

The results give evidence for greater efficacy of the IP application of clindamycin as a first -Iine antibiotic compared to the oral route for the treatment of tunnel infections.

Evaluation of an antimicrobial-impregnated continuous ambulatory peritoneal dialysis catheter for infection control in rats

Infection is the most serious complication arising in long-term continuous ambulatory peritoneal dialysis (CAPD), specifically peritonitis and exit-site infection. The initial weeks after implantation is the crucial period during which bacterial colonization of the catheter results in maximal morbidity, with Staphylococcus aureus being the most virulent organism. We developed an antimicrobial-impregnated CAPD catheter by impregnating the cuff and tubing with chlorhexidine, silver sulfadiazine, and triclosan in a polymer matrix. The antimicrobial spectrum and duration were shown by measuring zones of inhibition to various bacteria and fungi over the course of 5 to 10 days. Activity also was assessed subsequent to soaking in trypticase soy broth containing 20% bovine serum over the course of 1, 3, and 7 days. Significant antimicrobial activity was shown against all organisms tested for, with particular efficacy against gram-positive bacteria. Catheters were implanted in rats followed by inoculation of the exit site with S aureus. Seven days postimplantation, 0% of the impregnated catheters were colonized intraperitoneally compared with 100% of the control catheters. Similarly, 12.5% of the impregnated catheters were colonized at the exit site, whereas 100% of the controls were colonized. Histologic analysis showed that this combination and concentration of antimicrobials did not retard healing or cause increased inflammation compared with control catheters after 3, 10, and 24 days postimplantation in noninoculated rats.

Assessment of the FAN anaerobic bottle for culture of continuous ambulatory peritoneal dialysis fluid using the BacT/Alert system

The purpose of this study was to determine if the newly available FAN anaerobic bottle (FANAN) alone would be comparable to the combination of the FAN aerobic (FANAE) plus the standard BacT/Alert anaerobic (REGAN) bottles for culture of continuous ambulatory peritoneal dialysis (CAPD) fluid from patients with CAPD peritonitis. CAPD fluid (10 mL) was injected into each bottle, which was then monitored by the BacT/Alert instrument by using a 7-day protocol. Aerobic and anaerobic terminal subculture were performed on all bottles before they were classified as being culture negative. There were 181 effluents received that were suitable for analysis. Growth was detected in 76 (42%) effluents by at least one method. FANAE was the single best medium detecting 84/96 (88%) of all organisms whereas the FANAN and REGAN each detected 69/96 (72%). The combination of FANAE and REGAN bottles detected 92/96 (96%) isolates, which was significantly better than the FANAN or FANAE alone for isolate recovery (p < 0.001). The isolates that were missed by the FANAN but that were recovered by either FANAE or REGAN were all facultative anaerobes commonly detected in CAPD fluids. Terminal subculture revealed otherwise undetected pathogens in 3.9% of positive effluents, usually Pseudomonas aeruginosa. Based on our data, FANAE was the single best bottle for detection of CAPD peritonitis and, in combination with an anaerobic bottle, detected growth from the most effluents. FANAN alone could not substitute for the FANAE/REGAN combination. Although terminal subculture remains controversial, we recommend routine aerobic subculture to ensure that no P. aeruginosa isolates are missed.

Long-term clinical experience with continuous ambulatory peritoneal dialysis: access-related problems

Patients with end-stage renal failure can be treated with peritoneal dialysis, which is based on the capacity of the peritoneum to exchange fluid and metabolic products. To achieve this, dialysis fluid has to be instilled in the abdominal cavity through a permanent percutaneous access device. Apart from the advantages of peritoneal dialysis, severe problems are related to the access device. In this study, catheter-related morbidity and mortality are described, as found in the patient population from the University Hospital, Nijmegen, The Netherlands. The overall rates of exit-site infections and peritonitis are respectively 0.80 and 1.36 infection episodes per patient-year. Furthermore, it appeared that exit-site infections and peritonitis are the main reasons for discontinuation of dialysis and removal of the catheter. A correlation between the occurrence of peritonitis and exit-site infections was found. Also, the efficacy of the antibiotic treatment necessary to control these infectious complications is described. It is concluded that the design and the materials used to manufacture the currently used access device are the main reason for the existing morbidity in peritoneal dialysis. Therefore, more efforts should be undertaken to improve the access device, in which the design and the material used are critically considered.

Pseudomonas peritonitis in peritoneal dialysis patients: the Network #9 Peritonitis Study

To determine risk factors for the development of Pseudomonas peritonitis (PsP) and outcomes of PsP, the authors compared peritoneal dialysis patients who developed PsP with peritoneal dialysis patients who developed non-Pseudomonas bacterial peritonitis (non-PsP). The authors also sought to determine if there were differences in patients who had resolution of PsP compared with those patients whose PsP did not resolve. The data were derived from the prospective Tristate Renal Network Peritonitis and Catheter Survival Study. Resolution in this study was defined as clearing of peritoneal dialysate on visual inspection, with up to three courses of antibiotic therapy allowed. Catheter removal, switch to hemodialysis, or death were outcomes that were considered separately from resolution because of the study design. There were 31 cases of PsP in 28 patients and 886 cases of non-PsP identified in 667 adult patients. There were no differences in race, gender, age, or incidence of diabetes between the groups. The PsP group had a 25% incidence of previous exposure to immunosuppressive agents, whereas it was 10.6% in the non-PsP group (P = 0.028). PsP infections were more frequently associated with concomitant exit and tunnel infections, higher hospitalization rates, increased incidence of catheter loss, switch to hemodialysis, and a worse rate of resolution when compared with non-PsP (all, P < 0.05). Logistic regression could not identify patients at increased risk of PsP. PsP resolved with antibiotic therapy only in 10 of 31 episodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Serological response to coagulase-negative staphylococci in patients with peritonitis on continuous ambulatory peritoneal dialysis

Sera and dialysis effluent from 20 patients on continuous ambulatory peritoneal dialysis (CAPD) with coagulase-negative staphylococcal (CNS) peritonitis were examined by immunoblotting for antibody activity against CNS. Immunoblotting was highly sensitive and demonstrated significantly greater antibody activity in serum and dialysate of infected patients compared with that of uninfected CAPD patients or healthy volunteers. Fourteen of 20 infected CAPD patients had strong antibody activity (> 7 bands); one patient had equivocal activity. Five patients had weak antibody activity, two of whom suffered from recurrent peritonitis with distinguishable CNS strains despite a satisfactory CAPD technique. One patient with a poor CAPD technique had strong antibody activity, but suffered from recurrent peritonitis. Examination of sequential sera suggested that seroconversion occurred soon after insertion of the Tenckhoff catheter, possibly in the absence of clinical infection. Antibody activity against a 25 kDa staphylococcal protein was significantly associated with peritonitis.

Controlled trial of a Y-set dialysis delivery system to prevent peritonitis in patients receiving continuous ambulatory peritoneal dialysis

Peritonitis rates were compared in patients receiving continuous ambulatory peritoneal dialysis (CAPD) via either a Y-set dialysate delivery system or a standard system. Forty patients in each arm of the trial were matched for age (range 20-67 years, mean 49 years), and remained in the study for similar periods (range 3-36 months, mean 14.1 months). The observation time was 564 patient-months for each arm of the trial. There were 22 episodes of peritonitis in nine out of 40 patients using the Y-set and 57 episodes in 21 out of 40 patients using the standard system (P = 0.005 Wilcoxon signed rank test for episodes, P = 0.02 McNemar's chi 2 test for patients). Peritonitis rates were one episode per 25 patient-months in the Y-set group, and one episode per 9.7 patient-months in the standard group. In the Y-set group there were significantly fewer episodes caused by coagulase-negative staphylococci and Acinetobacter spp. There was no difference in the rate of episodes caused by Staphylococcus aureus, streptococci, enterococci, corynebacteria, enterobacteria or pseudomonads. There was no difference in the incidence of catheter exit wound infections. The Y-set dialysis delivery system is effective in reducing peritonitis rates in CAPD patients caused by organisms derived from the commensal skin flora, principally coagulase-negative staphylococci, but does not reduce peritonitis caused by other organisms.

Susceptibility testing of bacteria recovered from patients with peritonitis complicating continuous ambulatory peritoneal dialysis

Antagonism of antibiotic activity by peritoneal dialysate has been postulated to be a cause of failure of treatment of peritonitis complicating continuous ambulatory peritoneal dialysis. We evaluated by a case-control study whether unexpected treatment failure could be attributed to such antagonism. Bacteria isolated from 34 patient episodes of peritonitis treated with the same regimen of ciprofloxacin monotherapy were studied. Ciprofloxacin was significantly less active in dialysate than in Iso-Sensitest broth (IB). The median MIC in IB was 0.5 microgram/ml, increasing to 2.0 micrograms/ml for both fresh dialysate (FD) (P = 0.003) and pooled dialysis effluent (PDE) (P = 0.03); the median MBC in IB was 8.0 micrograms/ml, increasing to 128.0 micrograms/ml in FD (P = 0.0002) and 64.0 micrograms/ml in PDE (P = 0.02). However, no significant differences were found in the results for patients suffering unexpected treatment failure (relapse of peritonitis) compared with the results for patients whose infection resolved without sequel. In IB the median MICs for relapsers and nonrelapsers were 1.0 and 0.5 microgram/ml, respectively (P = 0.88); median MBCs were 32.0 and 4.0 micrograms/ml (P = 0.19). In FD median MICs for relapsers and nonrelapsers were 2.0 and 1.0 micrograms/ml (P = 0.06); median MBCs were 128.0 micrograms/ml for both groups (P = 0.84). In PDE the median MICs were 2.0 micrograms/ml for both groups (P = 0.78); median MBCs were 256.0 and 64.0 micrograms/ml (P = 0.17). We therefore found no evidence to suggest that antagonism of antibiotic activity by dialysate is a cause of treatment failure or that conventional methods for laboratory susceptibility testing in peritonitis complicating continuous ambulatory peritoneal dialysis should be abandoned in favor of testing in media containing dialysate.