Viridans-group streptococcal infections in immunocompromised hosts

Viridans streptococci, a diverse group of streptococcal species, are import ant causes of sepsis and pneumonia in the neutropenic host and sepsis and m eningitis in the neonate. The oral mucosa is the most common portal of entr y. Among the factors that predispose to development of viridans streptococc al sepsis are: profound neutropenia; mucositis, especially oral mucositis; cytarabine (Ara-C) therapy, which seems to have an effect beyond its associ ation with mucositis; young age; and trimethoprim-sulphamethoxazole or quin olone administration. Fever is usually more than 39 degrees C and prolonged for several days even though blood cultures are typically negative after 2 4 h of therapy. The majority of patients recover uneventfully if appropriat e therapy is initiated early. However, fulminant septic shock may occasiona l occur at onset. Delayed shock 2 or 3 days after presentation may also occ ur despite administration of microbiologically effective antibiotics. In se vere cases, adult respiratory distress syndrome may be manifested two or th ree days after the initial bacteremia. There is considerable variability am ong institutions, but the median death rate associated with viridans strept ococcal sepsis is about 10%. Local susceptibility patterns should be used t o guide initial therapy for suspected viridans streptococcal infections. So me isolates of viridans streptococci are resistant to penicillins and cepha losporins, in which case vancomycin is preferred. Recurrence during subsequ ent neutropenic episodes is not unusual. (C) 2000 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved.