Intraperitoneal vancomycin absorption is higher when there is peritoneal inflammation, but the absorption decreases with recovery from peritonitis. Consequently, intraperitoneal maintenance doses are ineffective, reducing the rate of cure.

Conclusion:The response to treatment was very satisfactory.

Since the introduction of continuous ambulatory peritoneal dialysis (CAPD), there have been steady advances in the clinical and laboratory knowledge of infectious complications, the pharmacokinetics of antibiotics and improvements in catheters and devices to avoid peritoneal cavity contamination [1-4]. Nevertheless, peritonitis is the most important clinical complication of CAPD, resulting in 15% technique failure [5] and 2%-3% mortality [6].

Gram-positive peritonitis continues to be common. Several treatments are used, but none is infallible. First-generation cephalosporins and vancomycin used in continuous and intermittent protocols have varying success rates. Bailie and Manley observed vancomycin has an extremely advantageous pharmacokinetic profile, as one single intraperitoneal dose of 15-30 mg/kg results in adequate serum and dialysate concentrations for several days, at least in CAPD patients [7,8].

Intraperitoneal maintenance doses of vancomycin become ineffective because the intraperitoneal absorption is higher when peritoneal inflammation is present [9-11], but decreases as the patient improves and peritoneal inflammation decreases, falling below the minimum inhibitory concentration and leading to relapse and refractory peritonitis [12].

Therefore, this prospective study evaluated the outcome of Gram-positive peritonitis (coagulase-negative and Staphylococcus aureus) treated with a protocol using intraperitoneal and then intravenous vancomycin.

In April 1996, we initiated a prospective treatment protocol for coagulase-negative Staphylococcus and S. aureus peritonitis comprising vancomycin at 2 g as an intraperitoneal loading dose, followed by intravenous vancomycin at 1 g twice in 5 days as maintenance treatment for coagulase-negative Staphylococcus and three times in 5 days for S. aureus. In addition, oral rifampin at 600 mg per day was prescribed for 5-7 days for S. aureus peritonitis.

During the period from 1 April, 1996, to 3 August, 2016, 113 patients undergoing peritoneal dialysis were enrolled [42 males (37.16%), mean age 54.19±15 years, total treatment time 6090 patient-months, and mean treatment duration 54±44 months]. Twenty two diabetic patients comprised 19.46% of the all PD patients. We examined the outcomes of all coagulase-negative Staphylococcus and S. aureus peritonitis episodes treated using this protocol from our database.

Peritonitis was defined as the presence of a cloudy dialysis effluent with more than 100 white blood cells/mm3 and a white blood cell differential count with greater than 50% polymorphonuclear cells, as previously described [13]. As part of the initial empirical therapy, the patients also received an aminoglycoside or third-generation cephalosporin, but these were stopped when the Gram stain or culture results were obtained.

Transfer-sets were changed 7-10 days from the onset of peritonitis when the effluent was clear and patients were symptom-free. Heparin (500-1000 U/L) was given regularly until the effluent was clear. The first cloudy effluent sample was cultured using standard microbiological techniques. We could not analyze all Gram-positive organisms in terms of methicillin resistance. The serum vancomycin levels were not measured.

We analyzed the Gram-positive peritonitis episodes and the treatment efficiency in terms of a 1) complete cure, 2) relapsing peritonitis, 3) catheter removal for refractory peritonitis, and 4) death. We defined complete cure as clinical and laboratory resolution of the episode. Relapsing peritonitis was defined as when an episode occurred within 4 weeks of the completion of therapy for a prior episode caused by the same organism or a negative effluent culture. Refractory peritonitis was defined as the absence of therapy success after 5 days of treatment necessitating catheter removal.

During the study period, 71 of 113 patients (62.8%) developed 185 episodes of peritonitis: 135 during CAPD and 50 during APD (1 episode per 32.92 patient-months, cumulative peritonitis rate 0.365). During this time, 46 of the 113 patients (41.4%) developed 51 episodes of coagulase-negative Staphylococcus peritonitis and 37 episodes of S. aureus peritonitis were recorded. With our treatment protocol, 47 (92.15%) of the coagulase-negative peritonitis episodes resolved and four catheters were removed for refractory peritonitis. In addition, 34 (92%) episodes of S. aureus peritonitis resolved, one patient died, and two catheters were removed. No relapsing peritonitis was observed. A summary of the outcomes with our protocol of treatment are shown in Table 1. It is also important to highlight that 34 of 37 peritonitis episodes with culture-negative were resolved. No red-neck syndrome was observed with intravenous vancomycin.

Peritonitis is the Achilles’ heel of peritoneal dialysis, and treatment failure may occur because of methicillin resistance or antibiotic levels below the minimum inhibitory concentration (MIC), probably related to the route of administration, dose, and interval between doses.

Vas et al. [14] used intermittent cefazolin as treatment and reported failure percentages of 0% for coagulase-negative Staphylococcus (methicillin sensitive; MS), 55% for coagulase-negative Staphylococcus (methicillin resistant; MR), and 33% for S. aureus. In patients given 2.0 g of vancomycin intraperitoneally in one bag repeated weekly for two further doses for coagulase-negative Staphylococcus, culture-negative peritonitis, or other Gram-positive organisms and three doses for S. aureus, the failure percentages were 8% for coagulase-negative Staphylococcus (MS), 27% for coagulase-negative Staphylococcus (MR), and 42% for S. aureus. Therefore, the overall methicillin resistance was 39%. Methicillin resistance plays a very important role in treatment failure, and is observed in 15%-20% of S. aureus and 30%-40% of S. epidermidis. The methicillin-resistance rate was 60% for coagulase-negative Staphylococcus and 10% for S. aureus at New Haven University [15], 40% for Gram-positive organisms at Michigan University [16], 60% for S. aureus in Japan [17], and 33% for S. aureus and 80% for S. epidermidis in Brazil [18]. The latter group reported a low cure rate using 1 g of cefazolin once a day and 0.2 mg/kg/day amikacin [18]. Lai et al. reported a 100% response rate for coagulase-negative Staphylococcus and 80% for S. aureus using cefazolin intraperitoneally at 500 mg/L once a day [19]. In addition, in a controlled study, the rate of cure was 84% with intraperitoneal vancomycin compared with 71% using cefazolin via the same route, and catheter loss was observed 1.3 times more often than with cefazolin [20]. Brown et al. observed an 82.5% cure rate with cefazolin once a day [21].

Krothapalli et al. and Obermiller et al. found that intravenous vancomycin was 85% effective for treating Gram-positive peritonitis [22,23]. Using 1 g of intravenous vancomycin weekly for 4 weeks, Mulhern et al. observed initial responses in 31 episodes, but 29% relapsed when the serum vancomycin level was below 12 mg/L (10). In a review of the treatment of Gram-positive peritonitis with intraperitoneal vancomycin, 80-90% of the episodes were eradicated [7]. Vargemezis et al. compared intraperitoneal and intravenous vancomycin, and observed relapsing peritonitis in patients given only two 1-g intravenous doses, the first on admission and the second 7 days later [24]. Similarly, Ballinger et al. found better results with intraperitoneal vancomycin [25].

Considering the increase in vancomycin-resistant organisms, the use of vancomycin as initial therapy is controversial [7]. However, intraperitoneal vancomycin is considered the first option, with first-generation cephalosporins for Gram-positive coverage (26-28). Bastani observed that the absorption of intraperitoneal vancomycin was 74% when there was peritoneal inflammation and 51% with normal peritoneum. Bunke et al. and Pancorbo et al. found similar levels of absorption (54% and 65%, respectively) with normal peritoneum [9-11].

Considering this, we developed a treatment protocol using intraperitoneal vancomycin initially and intravenous vancomycin for 5 days. Our study was limited because we did not measure the MIC or evaluate methicillin resistance in any patient.

In conclusion, we observed satisfactory treatment outcomes in our series, perhaps because the serum antibiotic levels during the treatment were sufficiently high. Further studies should verify the efficacy of our treatment protocol.

1. Churchill DN, Taylor DW, Vas SI, The Canadian CAPD clinical Trial Group. Peritonitis in CAPD: A multi-centre randomised clinical trial comparing the y-connector disinfectant system to standard system. Perit Dial Int. 1989; 9: 159-163.
2. Boyce N, Thomson NP, Atkins RC. Management of peritonitis complicating continuous ambulatory peritoneal dialysis: an Australian perspective. Perit Dial Bull. 1987; 7: 93-97. Ref.: https://goo.gl/cgQS5x  
3. Buoncristiani U. The Y set with disinfectant is here to stay. Perit Dial Int. 1989; 9: 149-150. Ref.: https://goo.gl/5tNiGB
4. Maiorca R, Cantaluppi A, Cancarini GC, Scalamogna A, Broccoli R. Prospective controlled trial of a Y connector and disinfectant to prevent peritonitis in continuous ambulatory peritoneal dialysis. Lancet. 1983; 2: 642-644. Ref.: https://goo.gl/8B7FFo
5. Gokal R. CAPD overview. Perit Dial Int. 1996; 16: S13-S18. Ref.: https://goo.gl/znekyt
6. Digenis GE, Abraham G, Savin E, Blake P, Dombros N, et al. Peritonitis-related deaths in continuous ambulatory peritoneal dialysis patients. Perit Dial Int. 1990; 10: 45-47. Ref.: https://goo.gl/oQ4enB
7. Bailie GR, Eisele G. Vancomycin in peritoneal dialysis associated peritonitis. Semin Dial. 1996; 9: 417-423.
8. Manley HJ, Bailie GR, Frye RF, McGoldrick MD. Intravenous vancomycin pharmacokinetics in automated peritoneal dialysis patients. Perit Dial Int 2001; 21: 378-385. Ref.: https://goo.gl/E1tty9
9. Bastani B, Spyker DA, Westervelt Jr FB. Peritoneal absorption of vancomycin during and after resolution of peritonitis in continuous ambulatory peritoneal dialysis. Perit Dial Int. 1988; 8: 135-136. Ref.: https://goo.gl/Pxjsw3
10. Bunke CM, Aronoff GA, Brier ME, Sloan RS, Luft FC. Vancomycin kinetics during continuous ambulatory peritoneal dialysis. Clin Pharmacol Ther. 1983; 34: 631-637. Ref.: https://goo.gl/XTIRfZ
11. Pancorbo S, Comty C. Peritoneal transport of vancomycin in four patients undergoing continuous ambulatory peritoneal dialysis. Nephron. 1982; 31: 37-39. Ref.: https://goo.gl/VCw8eT
12. Mulhern JF, Braden GL, O'Shea MH, Madden RL, Lipkowitz GS, et al. Trough serum vancomycin levels predict the relapse of gram-positive peritonitis in peritoneal dialysis patients. Am J Kidney Dis. 1995; 25: 611-615. Ref.: https://goo.gl/Fe13vA
13. Barone RJ, Alvarez Quiroga M, Ferraro J, Locatelli A, De Benedetti L. Exit Site Infection and Peritonitis. In Current Concepts in Peritoneal Dialysis. K. Ota et al. Editors. 1992. Elsevier Science Publishers p. 413-418.
14. Vas S, Bargman J, Oreopoulos DG. Treatment in PD patients of peritonitis caused by gram-positive organisms with single daily dose of antibiotics. Perit Dial Int. 1997; 17: 91-94. Ref.: https://goo.gl/hLkCI4
15. Troidle LK, Kliger AS, Finkelstein FO. Challenges of managing CPD-associated peritonitis. Perit Dial Int. 1999; 19: 315-318.
16. Mason NA, Zhang T, Messana JM. Methicllin-resistance patterns associated with peritonitis in a university-based peritoneal dialysis center. Perit Dial Int. 1999; 19: 483-486. Ref.: https://goo.gl/xVB4tk
17. Hashimoto H, Inoue M, Hayashi I. A survey of Staphylococcus Aureus for typing and drug- resistance in various areas of Japan during1992 and 1993. Jpn J Antibiot. 1994; 47: 618-626. Ref.: https://goo.gl/keJGYc
18. Onozato ML, Texeira Caramori JC, Barretti P. Initial treatment of CAPD peritonitis: Poor response with association of cefazolin and amikacin. Perit Dial Int. 1999; 19: 88-89. Ref.: https://goo.gl/aJnU3d  
19. Lai M-N, Kao M-T, Chen C-C, Cheung S-Y, Chung W-K. Intraperitoneal once-daily dose of cefazolin and gentamicin for treating CAPD peritonitis. Perit Dial Int. 1997; 17: 87-89. Ref.: https://goo.gl/KHdbEn
20. Flanigan MJ, Lim VS. Initial treatment of dialysis associated peritonitis: A controled trial of vancomycin versus cefazolin. Perit Dial Int. 1991; 11: 31-37. Ref.: https://goo.gl/Ddx3qh
21. Brown EA, Goldberg LC, Clemenger M, Azadian B. Effective treatment of peritonitis using a once-daily vanomycin-free regime in CAPD and APD (Abstract). Perit Dial Int. 1999; 19: 30.
22. Krothapalli RK, Senekjian HO, Ayus JC. Efficacy of intravenous vancomycin in the treatment of gram- positive peritonitis in long-term peritoneal dialysis. Am J Med. 1983; 75: 345-348. Ref.: https://goo.gl/p30HRq
23. Obermiller LE, Tzamaloukas AH, Leymon P, Avasthi PS. Intravenous vancomycin as initial treatment for gram positive peritonitis in patients on chronic peritoneal dialysis. Clin Nephrol. 1985; 24: 256-260. Ref.: https://goo.gl/FKl2kW
24. Vargemezis V, Pasadakis P, Thodis H, Coucudis P, Peihaberis P, et al. Vancomycin therapy for gram-positive peritonitis in patients on CAPD. Adv Perit Dial. 1989; 5: 128-129. Ref.: https://goo.gl/CxjeXf
25.  Ballinger AE, Palmer SC, Wiggins KJ, Craig JC, Johnson DW, et al. Treatment for peritoneal dialysis-associated peritonitis. Cochrane Database Syst Rev. 2014; 4. Ref.: https://goo.gl/2nFCe8 
26. Keane WF, Bailie GR, Boeschoten E, Gokal R, Golper TA, et al. Adult peritoneal dialysis related-peritonitis treatment recommendations: 2000 Update. Perit Dial Int. 2000; 20: 396-411. Ref.: https://goo.gl/4EO8aD
27.  Li PK, Szeto CC, Piraino B, Bernardini J, Figueiredo AE, et al. Peritoneal ISPDDialysis-related infections recommendations: 2010 update. Perit Dial Int. 2010; 30: 393-423. Ref.: https://goo.gl/0sN2ue
28. Li PK, Szeto CC, Piraino B, de Arteaga J, Fan S, et al. ISPD peritonitis recommendations: 2016 Update on prevention and treatment. Perit Dial Int. 2016; 36: 481-508. Ref.: https://goo.gl/6j2oz6