Seasonal predominance of atypical agents in adult community-acquired pneumonia in India's northeastern region: Is it the time to look again at empirical therapy guidelines?

Atypical agents such as Mycoplasma, Legionella, Chlamydia species, and Coxiella burnetii (Q-fever agent) are responsible for some adult community-acquired pneumonia (CAP). Insufficient studies on this topic can be blamed for the failure to include atypical pathogens in empirical management. We followed adult CAP cases for two years, and samples (respiratory and serum) were tested by culture, ELISA (IgM, IgG, and IgA), and PCR. A risk factor analysis was performed. Overall in 21.3% adult CAP patients, atypical agents found were Mycoplasma pneumoniae (51.5%), Legionella pneumophila (28.8%), and Chlamydophila pneumoniae (19.7%). However, amongst patients <60 years of age and in the summer season, the proportion of atypical agents increased significantly. There is thus a need to re-examine empirical antibiotic regimes.