Stenotrophomonas maltophilia (S. maltophilia) is a non-fermenting gram-negative bacillus. It behaves like an opportunistic pathogen, mainly producing nosocomial infections and affecting immunosuppressed patients. It has low virulence so it is exceptional in healthy patients. The most frequent predisposing factors are having a tumor disease, neutropenia, diabetes mellitus, receiving immunosuppressive treatment or previous treatment with broad-spectrum antibiotics, being a carrier of prosthetic material or permanent vascular devices and have required a prolonged hospitalization.1

It is characterized by resistance to different groups of antimicrobial agents including beta-lactams, aminoglycosides and fluoroquinolones.2 The usual treatment is trimethoprim-sulfamethoxazole associated with one or two more intraperitoneal or intravenous antimicrobials. The period of treatment is prolonged to eradicate the germ and in many cases the removal of the peritoneal catheter is required.2

It is an uncommon cause of peritonitis in patients on peritoneal dialysis (PD), which leads to great virulence and hospitalization in most cases. In addition, since long-term treatment is required, the onset of other opportunistic diseases and fungal peritonitis is not infrequent increasing the morbidity and mortality of the patients affected.3

We report the case of a 54-year-old patient on an automated peritoneal dialysis (APD) program with chronic kidney disease secondary to anticalcineurinics as part of the immunosuppressive treatment of left lung transplantation 3 years before the initiation on PD. During the first year of renal replacement therapy, there were 3 episodes of peritonitis due to polymicrobial etiology, negative culture and Enterococcus faecalis, respectively. After 14 months of onset, a new case of peritonitis was diagnosed with turbid fluid, abdominal pain and 1050 nucleated cells/mm3 in the peritoneal effluent with 85% polymorphonuclear (PMN). It was empirically treated with intravenous vancomycin and intraperitoneal ceftazidime and with prophylaxis of fungal peritonitis with fluconazole. After an initial improvement, 3 days after the onset of the episode, there was worsening of the general condition and a cell count (2020 nucleated cells with 90% PMN). At that time in the peritoneal fluid it was cultured a multiresistant S. maltophilia sensitive to trimethoprim-sulfamethoxazole that was added to the previous treatment. After a further transient improvement, the cell count increased again, which is why it was decided the removal of the peritoneal catheter and definitive transfer to hemodialysis after several episodes of severe peritonitis caused by multiresistant germs and requiring hospital admission.

Our patient had several risk factors; in addition to the triple immunosuppressive therapy for the treatment of lung transplant, the patient had suffered several episodes of infection during the last year. In this same period the patient had required antibiotics to treat upper respiratory infection and required hospital admission for cytomegalovirus infection and Clostridium difficile toxin, with the corresponding antimicrobial treatment during 3 months before infection with S. maltophilia.

In several series previously published, it has been possible to preserve the peritoneal catheter in site in 40% of the cases3–5 by the administration of 2 or 3 drugs and in another case the patient was cured by adding ceftazidime to the sealed catheter.6 None of these patients were on immunosuppressant therapy.