Acute cholecystitis and bacteraemia due to Streptococcus bovis biotype II

Dear Editor

Streptococcus bovis (SB) is a gram-positive, catalase negative, facultative anaerobic coccus that forms part of the usual flora in the digestive system of 10% of healthy people.¹ SB belongs to the “bovis” group or Group D streptococci. This Group contains various species: S. equinus, S. gallolyticus (subspecies galactolyticus - biotype I – and pasterianus – biotype II/2), S. infantarius (SB biotype II/1), and S. alactolyticus. SB biotype I, the most common in our area, is more closely related with colorectal cancer and SB biotype II/1 with non-colonic cancers.^2–5 The usual portal of entrance is the digestive system, though other portals exist, such as the urinary tract.⁶ The most typical clinical presentation of SB infection is bacteraemia, being the second leading cause of streptococcal endocarditis.⁷ Although the disease most commonly associated with SB bacteraemia is colon cancer, SB bacteraemia has also been linked to other non-colonic neoplastic diseases, both digestive (gallbladder, pancreas, duodenum) and non-digestive (lung, ovaries, and even haematological cancer)^8,9 and with non-neoplastic digestive diseases, such as inflammatory bowel disease⁶ or liver disease.^8,10 However, its involvement in processes related with diseases of the bile tract is unusual, with very few cases reported.¹¹ We present a new case of SB bacteraemia associated with acute cholecystitis and review the cases published to date.

The patient was a 73-year-old man with a history of ischaemic heart disease, hypertension and insulin-dependent diabetes mellitus. He presented with a 24-hour history of periumbilical abdominal pain and vomiting of food. The patient had a temperature of 39 °C, a blood pressure of 120/70 mmHg, cutaneous-mucous jaundice and pain in the right hypochondrium, with no signs of peritoneal irritation. A blood test showed 17,000 leukocytes/mm³ with a left shift, creatinine 1.8 mg/dL, AST 48 IU/L, ALT 101 IU/L, alkaline phosphatase 257 IU/L and bilirubin 2.48 mg/dL, which was mainly the direct fraction. Empirical antibiotic therapy was started with intravenous ceftriaxone 2 g/d. An abdominal-pelvic scan showed biliary lithiasis, and slight thickening and oedema of the gallbladder wall with radiographic signs of cholecystitis. The blood culture isolated S. bovis, biotype II sensitive to penicillin, by API 20 Strept (BioMérieux SA, Marcy l’Etoile, France). The patient therefore continued antibiotic treatment for 14 days with an excellent clinical and analytical resolution. Serological testing for hepatotropic viruses was negative. An echocardiogram and a colonoscopic study were normal.

The subdivision of SB into three biotypes, I, II/1 and II/2, can have clinical importance as regards decision making. Bacteraemia due to biotype I, for example, is more often associated with endocarditis or colon cancer than biotype II bacteriaemia.^2,3 Lee et al.¹¹ reviewed cases of bacteraemia in the area of Hong Kong, where biotype II predominates (35 of 37 cases, 94.5%), and found just 4 cases of colon cancer and 4 of endocarditis. However, 38% of cases presented with biliary diseases (cholecystitis and/or cholangitis). The authors suggested that this higher prevalence was due to the frequency of biliary disease caused by infestation with Clonorchis sinensis, the ease of growth of this pathogen in bile compared to other streptococci, and possibly also to the presence of surface receptors that facilitated their adhesion to the bile tract.^11,12 To date, a total of 24 cases of cholecystitis/cholangitis associated with SB infection have been reported ^6,11,13–16 (Table 1), with 15 of these indicating a clear association of biliary disease with biotype II. Whatever the case, in the series of Lee et al, the strains isolated in the 4 cases of endocarditis and the 4 cases of bacteraemia associated with colon cancer were all biotype II. This suggests that when faced with SB biotype II bacteraemia it is always necessary to check for the presence of endocarditis and colon cancer.

Table 1.

Cases of bacteraemic cholecystitis/cholangitis due to S. bovis

Author (Ref.)	Cases	Year	Place	Biotype
Murray^12	2	1978	New York	NM
Pigrau^14	3	1988	Barcelona	NM
Zarkin^6	3	1990	Baltimore	NM
Lee^11	14	2003	Hong Kong	II
Landau^15	1	2006	Tel Aviv	NM
Sams^16	1	2008	Augusta	II
Medina^*	1	2010	Malaga	II

NM: not mentioned.

*

Case published in this report.

In summary, we report a new case of bacteraemia due to S bovis biotype II associated with cholecystitis, which resolved after treatment with antibiotics.