HIGH PREVALENCE OF SIMKANIA-Z, A NOVEL CHLAMYDIA-LIKE BACTERIUM, IN INFANTS WITH ACUTE BRONCHIOLITIS

The newly described microorganism ''Simkania Z'' (''Z''), an obligate intracellular, penicillin-resistant microorganism most closely related to the chlamydiae, has been associated with adult community-acquired pneumonia, The possible involvement of ''Z'' in bronchiolitis in infan ts was examined in a prospective study of 239 infants with bronchiolit is and 78 controls. Other potential etiologic agents sought were respi ratory syncytial virus (RSV), adenovirus, and cytomegalovirus. Evidenc e for the presence of ''Z'' in nasopharyngeal wash specimens (polymera se chain reaction and/or culture) was found in 25% of infants with bro nchiolitis, while controls were all negative (P < .001), A serum IgA r esponse to ''Z'' infection was detected by immunoperoxidase assay in 1 5% of infants with bronchiolitis versus 1.3% of controls (P < .001), C linical findings were not different for infants with bronchiolitis ass ociated with RSV alone, ''Z'' alone, or RSV and ''Z'' together. The hi gh prevalence of ''Z'' in infants with bronchiolitis, often accompanie d by an immune response, suggests a possible etiologic role of this ag ent in the disease.