Peritonitis is a serious problem for peritoneal dialysis (PD) patients, and is a major cause of hospitalization, catheter loss and transfer to haemodialysis [1]. We present a peritonitis episode caused by an unusual pathogen, Gemella morbillorum. A 55-year-old man was admitted to hospital after noticing that his dialysis effluent was slightly cloudy. He received three exchanges of 1.36% and one exchange of 2.27% 2000 ml of PD solution (Baxter-Dianeal 137, Deerfield, IL) in a day. He had no prior history of peritonitis. The clinical picture was dominated by mild diffuse abdominal pain and tenderness. Analysis of the peritoneal effluent demonstrated a white blood cell (WBC) count of 480/µl with 90% neutrophils. Gram stain of the effluent revealed no bacteria. Culture of the specimen grew slow-growing, Gram-positive, pleomorhic, catalase-negative bacteria that were identified as G.morbillorum. The minimal inhibitory concentrations determined by E Test® for penicillin and vancomycin were 0.006 and 1 mg/l, respectively, which were interpreted as susceptible. Prior to identification of the bacteria, ampicillinsulbactam (1.5 g bid) and ciprofloxacin (200 mg bid) were started intravenously as the regular therapy for CAPD peritonitis in our institution, and the same combination continued for 14 days. The WBC of the peritoneal effluent dropped to zero at the end of the first week of therapy. The patient was well when he was seen 1 month after his discharge.
Gemella morbillorum and Gemella hemolysans are Gram-positive coccal commensal organisms of the mucous membranes of humans. Only a few cases of Gemella infection have been reported to date, and have been predominantly endovascular infections [2]. The first episode of peritonitis caused by G.morbillorum was successfully treated with cefazolin [3].
Gemella may be more involved in clinical disease than is presently recognized. They can be incorrectly identified as viridans streptococci, identified as Neisseria spp. because they are easily decolorized during Gram staining or left unidentified [2]. Our patient had no other underlying disease besides end-stage renal failure and no other infectious foci prior to this peritonitis episode. Translocation from the gastrointestinal tract may be responsible for this episode. We did not culture the stool of the patient before antimicrobial therapy to demonstrate Gemella. It is difficult to estimate how this microorganism caused this episode.
Gemella infections are seldom seen, and the identification in the laboratory has some limitations because of the characteristics of this bacteria. Therefore, the microbiological samples should be interpreted carefully and Gemella should be taken into consideration when slow-growing, catalase-negative, Gram-positive cocci are seen in samples. There are fatal Gemella infection reports in the literature [4,5]. Our case improved well with a ß-lactam antibiotic as in the other patient mentioned above [3]. The response of two patients to therapy is not enough to reach a general conclusion about the prognosis, but the in vitro susceptibility results may be a useful guide in the management of these patients.
Conflict of interest statement. None declared.
Baskent University Faculty of Medicine Infectious Disease and Clinical Microbiology Ankara Turkey Email: okurtazap{at}baskent-ank.edu.tr
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