Epidemiology of rare bacterial, parasitic, and fungal pathogens in India.

Rare human pathogens are infrequently observed clinically but can lead to undiagnosed infections, delays in treatment, severe complications, including death. Traditional diagnostic tools cannot routinely detect rare infections in public health settings. This study focuses on the incidence and outcomes of rare pathogenic microorganisms over 13 years (2010-2022) using PubMed database to obtain epidemiological data on rare bacterial, parasitic, and fungal infections in hospitals throughout India. A total of 974 articles were screened using case studies, datasets, comments, classical articles, letters, editorials, observational studies, and meta-analyses. Our analysis identified 28 rare bacteria, six parasites, and five fungal species infections in India. Fatal cases were associated with rare bacterial and fungal infections, including two from pan-drug-resistant bacteria (both from the genus). A total of 10 bacterial species displayed multi-drug resistance; one was extensively drug-resistant, and eight remained unclassified. Of the 83 patients with these rare infections, the mortality was ∼8.4% (seven of 83). Considering drug resistance and high mortality, prompt diagnosis of rare pathogens is crucial to controlling their spread. An increased awareness within the Indian health care system focusing on diagnostics, record keeping, and data sharing will be necessary to enhance surveillance.