[Current importance of resistance of group A streptococci to tetracyclines].

The resistance of group A streptococci to tetracyclines is a long-standing phenomenon, observed in numerous countries. Sixty strains of group A streptococcus, isolated in 1975 and 6976 at the Claude Bernard Hospital, were tested against natural and semi-synthetic tetracyclines and penicillin G. Whilst sensitivity to the latter was constant, approximately 30% of strains were resistant to tetracyclines. Amongst them, minocycline was nevertheless a little more active than natural tetracycline and doxycycline. The mechanism of this resistance would seem to be extra-chomosomal.