Characterization of in vitro-generated and clinical optochin-resistant strains of Streptococcus pneumoniae isolated from Argentina

CORTES P; ALBARRACIN ORIO A; REGUEIRA M; PIÑAS G; ECHENIQUE J

ASM

Año: 2008 vol. 46 p. 1930 - 1930

strong>Optochin susceptibility is a key test used for pneumococcal diagnosis, but optochin-resistant (OptR) pneumococci have been reported in the last 2 decades. In this work, we characterized eight Optr clinical strains which presented a new mutation, G47V, a predominant A49S mutation (recently reported in Brazil) and A49T.These mutations were found in the c subunit of the F0F1 ATPase encoded by the atpC gene, and W206C was found in the a subunit encoded by the atpA gene. The Optr clinical isolates were analyzed by BOX PCR, multilocus sequence typing, and serotype and antimicrobial resistance profiles, and they showed no epidemiologicalrelationship. To characterize the Optr mutations that could emerge among clinical strains, we studied a pool of spontaneous OptR colonies obtained in vitro from the virulent D39 strain. We compared the atpAC mutations of these OptR pneumococci (with or without passage through C57BL/6 mice) with those described in the clinical isolates. This