BACTEREMIA DUE TO VIRIDANS STREPTOCOCCI THAT ARE HIGHLY RESISTANT TO PENICILLIN - INCREASE AMONG NEUTROPENIC PATIENTS WITH CANCER

We prospectively studied 260 episodes of bacteremia that occurred over a 6-year period in neutropenic patients with cancer, Twenty-three epi sodes were caused by viridans streptococci. Thirteen (57%) of these st rains were penicillin-resistant (MICs of penicillin ranged from 0.25 m u g/mL to 8 mu g/mL). Ten of the 13 penicillin-resistant strains (77%) were highly resistant to penicillin (MIC, greater than or equal to 4 mu g/mL). Rates of bacteremia due to highly penicillin-resistant virid ans streptococci increased significantly from zero episodes per 1,000 admissions in 1987 to 17 episodes per 1,000 admissions in 1992 (P = .0 03), In a comparison between penicillin-resistant and penicillin-susce ptible viridans streptococci bacteremia, the administration of beta-la ctam antibiotics during the previous 2 weeks was the only factor signi ficantly associated with penicillin-resistant eases: 9 (69%) of 13 pat ients with penicillin-resistant bacteremia had received beta-lactams v s, 2 (20%) of 10 patients with penicillin-susceptible bacteremia (P = .036). These findings may have significant clinical implications in th e choice of both antimicrobial prophylaxis and empirical antibiotic re gimens.