Study Finds Rise In Chest Infections Due To Lesser-Known Bacteria In North India

A new study from Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh reveals that nearly 37% of pertussis-like cases in North India between 2019-23 are caused by Bordetella holmesii, a lesser-known bacterium.

31 Oct 2025, 05:05 · www.ndtv.com

In many parts of north India, cases of persistent coughs, whooping-type symptoms and chest infections have long been attributed to the usual culprit: whooping cough caused by Bordetella pertussis. But a new study from PGIMER, Chandigarh, suggests a dramatic change in the microbial landscape. The surveillance programme spanning 2019 to 2023 found that a lesser-known bacterium, Bordetella holmesii, is now responsible for a substantial fraction of pertussis-like illness in children aged roughly 5-10 years and above. This finding has major implications for diagnosis, treatment and public-health policy in India, especially because mis-attribution to pertussis may affect therapeutic choices and contagion control measures.

With B. pertussis infections reported to have dropped from about 15-20% to just 2-5% in the studied sample, and B. holmesii rising markedly, clinicians and laboratories may need to re-tool their understanding of chest infections in children and adolescents.

What The Study Found

The PGIMER team analysed 935 suspected pertussis cases from 2019 to 2023. They found that approximately 37% of these were caused by Bordetella holmesii, overtaking Bordetella pertussis in prevalence. The increase was most notable in 2023, particularly among the 5-10-year-old age group in northern India. According to ongoing surveillance data from 2015 onwards, B. pertussis prevalence fell from 15-20% to just 2-5%, while B. holmesii climbed.

Why This Matters

Bordetella holmesii is not as widely recognised or diagnosed in routine practice in India. Because it mimics the clinical picture of pertussis (whooping cough), including persistent cough, paroxysms, maybe inspiratory whoop in some, it can lead to misdiagnosis. The standard vaccines and surveillance systems focus heavily on B. pertussis. If a significant fraction of patients have B. holmesii instead, then control measures, therapeutic protocols and diagnostic algorithms may need revision.

Also noteworthy is the fact that after the COVID-19 pandemic lull, many respiratory infections rebounded globally and in India. Pertussis remains a public-health burden in Asia, including India and China. The changing pattern underscores that pathogen profiles are evolving, and so must our detection tools.

Indian Context And Public Health Implications

In India's crowded clinical settings, many chest infections are treated empirically. Recognising that a significant chunk of pertussis-like illnesses may stem from B. holmesii means empirical treatments may be sub-optimal. Moreover, hospitals and public-health agencies must update protocols: awareness campaigns for paediatricians, revision of laboratory diagnostic standards, and adding this bacterium to the list of pathogens tracked in respiratory illness surveillance.

For example, the PGIMER team, led by Dr Vikas Gautam and in collaboration with CSIR IMTECH, exemplified how institution-based surveillance can detect shifts in pathogen patterns. In a broader sense, respiratory illness burden in India remains high, so quick, accurate identification of causes means more targeted antibiotic use, fewer unnecessary investigations, and better outcomes.

The PGIMER study flags a paradigm shift. What we once assumed to be classic whooping cough cases may increasingly be caused by the lesser-known Bordetella holmesii. For India, this is more than academic. It reshapes diagnostics, treatment and public-health strategy for chest infections in children. Clinicians, labs and policy-makers must heed this change and broaden diagnostic frameworks, update surveillance systems and revisit vaccine and antibiotic guidelines.

In a country already burdened with respiratory illness, early detection and accurate targeting of pathogens like B. holmesii could help reduce misdiagnosis, improve outcomes and optimise resource use. The microbes evolve, our systems must keep pace.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your doctor for more information. NDTV does not claim responsibility for this information.

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