[2 newborn infants with septicemia caused by multiresistant Streptococcus mitis].

Multiresistant viridans streptococci had not yet been encountered in the Netherlands. In the spring of 1990 we isolated multiresistant S. mitis from blood of two Dutch neonates (minimal inhibitory concentration of penicillin 64 mg/l). In both patients septicaemia developed while they were being treated with beta-lactam antibiotics. Although viridans streptococci usually are extremely sensitive to penicillin and other beta-lactams, the possibility of development of (multi-)resistance in these microorganisms during antibiotic treatment should be kept in mind.