The nasopharyngeal culture in acute otitis media. A reappraisal of its usefulness
R. Schwartz, W. J. Rodriguez, R. Mann, W. Khan and S. Ross
Simultaneous cultures of the nasopharynx and middle ear exudate (obtained
by tympanocentesis) were obtained from 225 children (mean age, 34 months;
median age, 41 months) with suppurative otitis media. A 72% prediction rate
for middle ear pathogens was obtained by examining the nasopharyngeal
cultures after the strict observance of two essential prerequisites: (1)
the nasopharyngeal culture was immediately plated on appropriate solid agar
and (2) a semiquantitative method for bacterial enumeration was employed in
the reading of the nasopharyngeal culture plates. The technique was most
valuable where 2+ (greater than 25% up to 50% of total number of colonies
was a single pathogen) or greater of a single pathogen was recovered from
the nasopharynx. In only one instance, the semiquantitative nasopharyngeal
culture incorrectly predicted the middle ear pathogen if one was recovered.
Quantitative nasopharyngeal cultures were particularly useful in predicting
the presence of ampicillin-resistant Haemophilus influenzae and group A
streptococci as causative agents in otitis media.
