To the Editor,

Peritonitis is one of the main complications for patients on kidney replacement therapy with peritoneal dialysis. In many cases, peritonitis causes the technique to fail, meaning that the patient has to be transferred to haemodialysis.1,2

We present here the case of a patient with two relapses caused by the same germ, probably caused by the colonisation of the catheter, who responded well to treatment with intravenous daptomycin.

The patient was a 79-year-old male with stage 5 chronic kidney disease secondary to nephroangiosclerosis and/or diabetic nephropathy, who was on kidney replacement therapy with continuous ambulatory peritoneal dialysis. The patient also had long-term type-2 diabetes mellitus, arterial hypertension and pernicious anaemia.

The patient came to the emergency department 27 months after starting treatment with symptoms and a cell count in the drainage fluid compatible with peritonitis. The empiric protocol established in our department which includes vancomycin and ceftazidime was started and cultures were also taken.

Staphylococcus epidermidis grew in the peritoneal fluid in the following days. The treatment with ceftazidime was stopped and intraperitoneal vancomycin was continued on an ambulatory basis until the treatment had been followed for 15 days.

The patient once again had abdominal pain and cloudy fluid 7 after finishing the treatment. New cultures were taken and the empiric treatment was restarted, but this time it was accompanied with prophylactic antifungal treatment. S. epidermidis grew once again in the cultures with a similar antibiogram to the one seen during the first episode and with a similar minimum inhibitory concentration (MIC) for vancomycin to the previous one (2µg/ml). Given the growth of the same germ and the short time period between the end of treatment and the new episode, it was considered as a relapse and antibiotic treatment was indicated for three weeks with intraperitoneal vancomycin plus oral rifampicin. An ultrasound of the abdomen and the catheter tunnel was requested at that time in order to rule out intraperitoneal fluid collections or collections in the pathway of the catheter.

The patient had a new episode with exactly the same germ once the antibiotic treatment had been completed. The need to transfer the patient to haemodialysis was considered at this point in order to take out the catheter as colonisation was suspected. As vascular access was difficult, we decided to try treatment with intravenous daptomycin at a dose of 4mg/kg/48h for 10 days.

At present, four months after ending treatment, the patient has not had any new episodes. He has been able to continue with his dialysis treatment and we were able to avoid removing the peritoneal catheter.

Peritonitis relapse is defined as a new episode of peritonitis with the same result in the culture within four weeks of completing treatment. It is usually associated with resistance to antibiotics and a biofilm presence on the catheter. Studies have been published that report the need to increase the dose or use multiple antibiotics to eradicate the germ. In the case of S. epidermidis, it is recommended that treatment is continued for at least 21 days.3-6

There is little information in the medical literature which evaluates treatment with daptomycin in peritoneal dialysis by intravenous or intraperitoneal route. In our case, daptomycin was probably able to enter inside the biofilm on the catheter and eradicate the germ that was causing the peritonitis and the subsequent relapses.

Although clinical studies are obviously needed to determine how valid this therapeutic option is, it was very useful in our case as the patient did not have to have the catheter removed.

As a result, intravenous daptomycin is an option that must be taken into account when it is suspected that the catheter has been contaminated by S. epidermidis in patients with peritonitis on peritoneal dialysis.