This systematic review aimed to consolidate findings on the etiology of community-acquired pneumonia (CAP) among Indian adults. We adhered to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Guidelines 2020 and conducted a comprehensive search across databases including PubMed, Scopus-Elsevier, and hand-searched reference lists using key terms such as “Community-Acquired Pneumonia,” “CAP,” “Indian,” and “adults.” Articles published between January 2010 and January 2024 were included, with exclusions for studies involving pediatric populations, non-Indian patients, or those published before 2010. From an initial pool of 344 articles, duplicates were removed and titles and abstracts were screened, resulting in nine studies meeting the inclusion criteria. The analysis of pooled data comprising 1,643 Indian adult participants revealed the following pathogen distribution:
Streptococcus pneumoniae
was the most common organism, accounting for 33% of the cases. This was followed by
Klebsiella pneumoniae
at 23%,
Staphylococcus aureus
at 10%,
Mycoplasma pneumoniae
and
Legionella pneumophila
each at 7%, and
Chlamydia pneumoniae
,
Haemophilus influenzae
, and
Pseudomonas aeruginosa
each at 4%. Notably, the review highlights a rising incidence of
K. pneumoniae
in CAP cases, which is a significant concern and should be considered when treating CAP patients in India. The findings emphasize the importance of comprehensive diagnostic testing, including advanced methods such as bronchoalveolar lavage, urinary antigen tests, serology for atypical pathogens, and enzyme-linked immunosorbent assays, to improve diagnostic yield and guide targeted antibiotic therapy. This review underscores the need for updated empirical treatment guidelines that account for dominant pathogens. Future research should focus on employing advanced diagnostic methods to enhance understanding of CAP etiology.
