Streptococcus gallolyticus subsp. pasteurianus Peritonitis in a Patient on Continuous Ambulatory Peritoneal Dialysis

Sir,

We report the first case of Streptococcus gallolyticus subsp. pasteurianus peritonitis in a patient on continuous ambulatory peritoneal dialysis (CAPD). A 63-year-old male of Indian origin, on CAPD since April 2013, presented to us with CAPD peritonitis. He was admitted and initiated on intraperitoneal (IP) cloxacillin and ceftazidime as per International Society of Peritoneal Dialysis guidelines. His laboratory investigations were as follows: C-reactive protein 47 mg/L, total white cell count 4.3 × 10⁹/L, peritoneal dialysate (PD) cell count was 200 cells/mm³ with predominant polymorphs. Dialysate fluid cleared up on day 2 of treatment with subsequent cell count of 25 cells/mm³, and corresponding negative cell counts repeated twice. Preliminary reports revealed Gram-positive cocci in the dialysate fluid; therefore, IP ceftazidime was discontinued and IP cloxacillin maintained. However, on day 4 of treatment, PD culture grew S. gallolyticus subsp. pasteurianus, which was resistant to clindamycin, erythromycin, trimethoprim/sulfamethoxazole, and tetracycline but sensitive to cephalexin and penicillin G. IP cloxacillin was then changed to IP penicillin G 50,000 U per 2 L dialysate bag. He remained asymptomatic and was discharged, to complete 2 weeks of IP penicillin G on an outpatient basis.

Streptococcus has over 50 species in its genus. A serotype classification called Lancefield grouping was used to further classify beta-hemolytic streptococci based on specific carbohydrates present on the bacterial cell wall. S. gallolyticus subsp. pasteurianus is a newly classified group D Streptococcus species previously known as Streptococcus bovis type II/2. S. bovis has 2 biotypes: I and II. This new classification is due to their unique ability to be able to decarboxylate gallic acid.[1] Its unique genetic diversity has resulted in many subspecies that have been associated with an array of clinical implications.[2] They frequently inhabit the gastrointestinal tract of human and animals such as horses, cattle, pigs, and sheep. Besides its association with endocarditis and colorectal carcinoma, S. gallolyticus subsp. pasteurianus has been linked as a causative agent for meningitis and septicemia in patients with colonic carcinoma, cirrhosis, and chronic liver disease.[34] Immunocompromised patients have been known to succumb fatally to septicemia caused by S. gallolyticus subsp. pasteurianus.[5]

Our timely initiation of IP ceftazidime and cloxacillin and prompt revision of antibiotics therapy according to antibiogram on day 4 with IP penicillin G led to the successful treatment of peritonitis. Our experience and literature review suggests that S. gallolyticus subsp. pasteurianus infection must not be taken lightly. Awareness regarding the threat posed by this organism is important to ensure the prompt initiation of antimicrobial therapy.