A tale of three in symbiosis: TB-COVID-19-Bordetella coinfection.

Coinfections/mixed infections are common in the respiratory tract. Many times existing organisms have similar risk factors and clinical features that make the diagnosis difficult. Coronavirus diagnosed in 2019 (COVID-19) and tuberculosis (TB) are two such diseases. Patients with TB have lower cellular immunity and impaired pulmonary function. In such environment, atypical organisms, can infect and make the outcome unfavorable. A 21-year-old malnourished (body mass index- 15 kg/m) girl presented with fever and cough for 10 days. Sputum for Cartridge Based Nucleic Acid Amplification Test demonstrated Mycobacterium tuberculosis with no rifampin resistance. Fever persisted (100-101°F) and saturation was dropping even after 10 days of antitubercular treatment. A repeat reverse transcription-polymerase chain reaction was done and was positive. In view of persistent symptoms after 20 days, bronchoscopy was done, and cultures showed Bordetella bronchiseptica. Fever and symptoms resolved completely after initiation of the sensitive drug. Diagnostic delay in coinfections can lead to increased morbidity and mortality.