Spectrum of respiratory pathogens in selected hospitals of Bangladesh

Background: Severe acute respiratory infection (SARI) still remains as one of the major causes of morbidity and mortality in both children and adults. Secondary bacterial infection or multiple viral infections contributes in evolution of these conditions. The aim of the study was to find the existence and pattern of infections among SARI cases according to age, to observe seasonality of circulating pathogens and to detect any co-infection. Methods and materials: Methods: A total of 301 SARI cases and 89 controls were enrolled from 10 sentinel sites of Bangladesh during the period of January to December 2017. Nasal and throat swab was collected from 108 cases with age less than 6 years of age (group A). Sputum was collected from 193 cases with age more than 6 years (group B) for multiplex PCR FTD 33 respiratory pathogens. Results: In group A and group B, about 82.5% and 87.6% of specimens were positive for pathogens respectively. In group A, the most commonly detected pathogens were Human rhinovirus (31.5%) followed by RSV (31%), HMPV (13%), HBoV (11%), HPIV-3 (10.5%), adenovirus (7%) and H. influenzae (1.5%). In group B, K.pneumoniae (31.6%) was found the most common organism followed by S. aureus (26%), Rhinovirus (25%), S. pneumoniae (23%), Moraxella catarrhalis (16%), RSV (16.75%) and Influenza A(12.3%).Seasonal variation showed that Rhinovirus infection found mostly in winter and Influenza A in summer. However, S. pneumonia, K. pneumoniae, HPIV, RSV and other pathogens were found round the year. The co-infection was detected in 227(58.2%) cases. Conclusion: The multiplex assay detects clinically important co-infection or mixed infection caused by viruses or bacteria or both in a single reaction and thus can help to detect respiratory pathogens within short period of time.