Recurrent peritonitis due to a suspected biofilm causes substantial morbidity in patients with peritoneal dialysis (PD) and sometimes leads to permanent abandonment of the technique.

We present the case of a 55-year-old man with a prior history of meningitis due to listeria, resolved with antibiotic treatment, chronic kidney disease (CKD) secondary to membranous glomerulonephritis in PD and an adrenal incidentaloma.

He visited our department owing to signs and symptoms of peritonitis due to clinically asymptomatic Staphylococcus epidermidis, which resolved with intraperitoneal (IP) vancomycin administered for 14 days. The post-treatment monitoring culture was negative.

Fifteen days after completion of antibiotic therapy, he had a recurrence of peritonitis caused by the same microorganism, and then he was treated with oral ciprofloxacin adjusted to antibiogram results without achieving a negative peritoneal fluid culture. Given the suspicion of recurring peritonitis due to a biofilm, intravenous (IV) daptomycin was started at a dose of 500mg/48h (residual diuresis 400ml/24h). After 10 days of treatment, the fluid remained slightly cloudy (220cells/μl, 55% polymorphonuclear cells, 45% monomorphonuclear cells), with a positive culture for S. epidermidis. Therefore, treatment was started with IP daptomycin (200mg loading dose followed by 40mg in each exchange) and maintained for 14 days. Throughout this time, the patient received associated antifungal prophylaxis.

The peritoneal fluid culture during and after treatment was negative.

After completing intraperitoneal antibiotic treatment, the patient resumed his usual therapy (automatic PD with a daytime exchange). He was scheduled for daptomycin lseal therapy, administered once per week for 4 weeks.

The sealing therapy protocol was performed using 35mg of daptomycin in 7ml of lactated Ringer's solution, with the abdomen empty for a minimum of 12h.

Currently, the patient remains asymptomatic, and has had no more episodes of peritonitis.

Daptomycin is a lipopeptide antibiotic indicated in the treatment of bacteraemia, right-sided endocarditis and complicated skin infections, with anti-biofilm activity.1

Several cases of treatment of peritonitis in PD with both IV and IP daptomycin have been reported.

Goedecke et al. showed that intravenous administration of daptomycin achieved plasma and peritoneal fluid levels greater than the minimum inhibitory concentration for microorganisms sensitive to this antibiotic. However, the study was conducted in a single patient.2

Subsequently, several cases were reported of peritonitis in PD that were successfully treated with IV daptomycin.3,4

A study of the pharmacokinetics of daptomycin in PD, with the dual aim of evaluating the drug's penetration of the peritoneal cavity and obtaining a dose regimen to be administered in this type of patients that offered safety and prevented toxicity, concluded that administration at doses of 4–6mg/kg/48h is an appropriate regimen for treating non-peritoneal systemic infections in patients who receive continuous ambulatory PD but, owing to its limited penetration of the abdominal cavity, its administration by the IV route is not safe for the treatment of peritonitis.5

In the case presented, daptomycin administered by the intravenous route did not achieve a negative peritoneal fluid culture. At the time of administration, peritoneal inflammation was not substantial, and the percentage of polymorphonuclear cells was only 55%, given that the patient was undergoing antibiotic treatment with ciprofloxacin, and the even lower penetration in the abdominal cavity could be attributed to this. Although there have been no studies on how peritoneal inflammation influences the concentration of daptomycin in the peritoneum, a study by Cardone et al.5 suggested that the peritoneal inflammation that occurs in the patients studied should to a certain extent promote the drug's penetration of the peritoneal cavity, without being able to ensure whether suitable levels would be achieved as the inflammatory process decreases.