Detection of pneumococci in the upper respiratory tract: comparison of media and culture techniques.

A survey for carriers of Streptococcus pneumoniae among 573 children was undertaken. Throat and nasopharyngeal cultures from 303 children disclosed pneumococci in 89 (29.4%) nasopharyngeal swabs but in only 8 (2.6%) throat specimens. Carriers of pneumococci were detected with frequencies of 84.4 and 79.9% on aerobically incubated 5% horse blood agar with a 5-micrograms optochin disk and on 5% horse blood agar with 5 mg of gentamicin per liter, respectively. Anaerobically incubated 5% horse blood agar yield pneumococci from 78.2% of 179 carriers. We consider the examination of nasopharyngeal secretions for optochin-susceptible alpha-hemolytic bacteria to be the most sensitive and convenient means for detecting carriers of pneumococci.