A person on anti-tubercular drugs complained of deafness and tinnitus in one ear. Which of the following is the causative agent?

Streptomycin is a tuberculocidal drug which is less effective than isoziazid or rifampicin. It is less commonly used as an antitubercular drug due to potential for nephrotoxicity and ototoxicity. It acts only on extracellular bacilli. It penetrates the tubercular cavities, but do not cross the CSF and has poor action in acidic medium. Common side effects of anti tubercular drugs: Isoniazid: Peripheral neuritis, hepatitis. Rifampin: Hepatitis, respiratory syndrome, cutaneous syndrome, flu syndrome, orange red colured body secretions. Pyrazinamide: Hepatotoxicity, ahralgia, flushing, loss of diabetes control. Ethambutol: Loss of colour vision or visual acuity, hyperuricemia.