It is estimated that about 40% of the Indian population is infected with Mycobacterium tuberculosis (TB), the vast majority of whom have latent TB. However asymptomatic pulmonary carriage of the TB bacteria contributes to sustenance of the disease in the community and subsequent transmission. The present study was carried out to see the prevalence of culture positive pulmonary tuberculosis in apparently asymptomatic individuals from the community.
The study population consisted of individuals wishing to migrate to the USA/UK/Canada/Australia and submitting for the mandatory health check prior to obtaining the Visa. Chest X ray was the initial screening test for diagnosis of tuberculosis. Individuals with any Xray abnormalities were directed to submit three sputum samples for microscopy and culture which was done on automated culture systems (BacTALERT and MGIT). First line drug susceptibility (INH, Rifampicin, Pyrazinamide, Ethambutol, Streptomycin) testing data was retrieved wherever available. Data was obtained for a period of seven years from August 2010 to July 2017.
Results: A total of 1,40,499 individuals presented for the health check. Of these, 1002 (0.7%) were further investigated using sputum microscopy and culture based on chest Xray findings. Of these, 42 (0.4%) individuals were sputum culture positive for Mycobacterium tuberculosis. Except two, none had any respiratory complaints. Eleven (27.5%) of them were smear positive for acid fast bacilli. Most of the patients (30%) belonged to the age group of 18-25years. 84% had no prior history of tuberculosis or treatment for TB. 59% isolates were sensitive to all first line drugs (Isoniazid, rifampicin, pyrazinamide, ethambutol and streptomycin). 27% were resistant to pyrazinamide alone. 14% were resistant to more than one first-line drug. There were no cases of multidrug resistance.
This is a unique large scale study which assesses prevalence of culture positive pulmonary tuberculosis in the urban Indian community. It stresses the need for more stringent public health measures to curb transmission of the disease in such a high endemic region such as India.
R. Subbulakshmi, None
V. Lakshmisree, None
U. Balasubramanian, None