EVALUATION OF CHLAMYDIA PNEUMONIAE AND MYCOPLASMA PNEUMONIAE AS ETIOLOGIC AGENTS OF PERSISTENT COUGH IN ADOLESCENTS AND ADULTS

EVALUATION OF CHLAMYDIA PNEUMONIAE AND MYCOPLASMA PNEUMONIAE AS ETIOLOGIC AGENTS OF PERSISTENT COUGH IN ADOLESCENTS AND ADULTS [Wadowsky RM et al. J Clin Microbiol 2002;40:637]: This is a report from the “Adult Pertussis Vaccine Efficacy Study Group” in which patients with a persistent cough for at least 5 days had throat cultures for detection of C. pneumoniae or M. pneumoniae by PCR and culture. Tests in 473 respiratory samples showed 4 had evidence of M. pneumoniae-associated infection (0.8%) and none had infection with C. pneumoniae. These results were further supported by paired sera in a subset of 99 patients that showed none of the patients had a four-fold rise in titer to either pathogen. Nevertheless, the seroprevalence rate for M. pneumoniae IgG exceeded 1:32 in 38%, and for C. pneumoniae it exceeded 1:8 in 74%. The authors conclude that these two pathogens are an infrequent cause of cough that persists over 5 days in adolescents and adults in the US. Comment. This is an important study in terms of what it does not show. There is a prevalent impression that URIs associated with persistent cough are frequently due to one of these two agents, and this impression becomes the fodder for antibiotic treatment. Much of the supporting data in prior reports have been based on serologic tests that are controversial in terms of accuracy and interpretive criteria. The diagnostic tests used here were what the authors described as “sensitive, specific, and robust PCR assays.”