A prospective study of infections with atypical pneumonia organisms in acute exacerbations of chronic bronchitis.

The objective of this paper was to study the incidence of 6 atypical pneumonia pathogens or atypical organisms in local patients admitted for acute exacerbation of chronic bronchitis. This is a prospective observational study. Over a period of 3 years (1995 to 1997), 90 patients admitted to a large general hospital in Singapore for acute exacerbation of chronic bronchitis were tested for the following infections: Legionella, Mycoplasma, Chlamydia, influenza A, influenza B and parainfluenza viruses, using paired serological examination. The antibiotic prescribing pattern by the attending physicians in these cases were also examined. Positive serologies were found in 31 patients (34%), of whom 26 patients (28%) had viral infections. The most common organism was influenza A with 18 positive serologies (20%). Five patients were tested positive for Legionella. There was no evidence of acute infections by Mycoplasma pneumoniae or chlamydia using serological tests.