Clinical spectrum and diagnostic yields of Mycoplasma pneumoniae as a causative agent of community-acquired pneumonia

INTRODUCTION: Infection with Mycoplasma pneumoniae (M. pneumonia) occurs worldwide which accounts for 15%-20% of cases of community-acquired pneumonia and indistinguishable clinically from other infectious causes of pneumonia. AIM: The aim of this study was to evaluate the real-time polymerase chain reaction (PCR) and to correlate it with other diagnostic methods such as culture, serology (ELISA), and conventional PCR along with the clinical signs and symptoms produced by M. pneumonia. MATERIALS AND METHODS: A total of 130 patients of all age groups presenting with clinical features of lower respiratory tract infections were enrolled over a period of 1 year and 2 months in a tertiary care hospital in Delhi. M. pneumoniae in throat swab samples was detected by real-time PCR, compared with culture, serology, conventional PCR, and clinical signs and symptoms. Univariate analyses were conducted to determine the association of M. pneumoniae infection among different categories of patients. RESULTS: Out of a total of 130 patients, 18 patients (14%) were positive for M. pneumoniae by any test; culture was positive in nine patients (50%), serology (IgM) in eight patients (44.4%), PCR in five patients (27.7%), and real-time PCR was positive in six patients (33.3%). Clinical signs and symptoms were higher in incidence in M. pneumoniae-positive patients. Age-matched healthy controls (30) were included in the study, and all were negative for any diagnostic test performed (P = 0.026). CONCLUSION: It was concluded that combination of M. pneumoniae-specific testing modalities is required for the diagnosis of this etiological agent rather than a single diagnostic method.