Comparison Of Lowenstein-Jensen Medium, Middlebrook 7h10 Medium And Bact/Alert 3d For Isolation Of Mycobacterium Tuberculosis From Clinical Specimens

Abstract

Introduction – Tuberculosis is the most common cause of death due to single infectious agent worldwide in adults. India alone accounts for 30% of global tuberculosis burden. There is manifest need for method of cultivation of mycobacteria that is reliable, economical and has short turnaround time.

Objective – Present study was attempted to assess the feasibility of using MB bact and middlebrook7H10 as primary isolation medium for mycobacteria. It has been compared with LJ medium, the gold standard.

Materials and Methods – Various clinical specimens from total of 230 clinically suspected cases of TB were studied. All isolates were decontaminated using modified Petroff’s method. Each sample was subjected to ZN staining and simultaneously inoculated onto LJ medium, middlebrook7H10 medium and MB bact. Growth from the culture were confirmed by ZN staining and speciated using biochemical reactions.

Results – Out of 230 samples screened, 116 isolates were obtained. Of the 116 all of them were isolated from MB bact, 82 were isolated by LJ medium and 62 were isolated by middlebrook7H10. 82 isolates were obtained by MB bact and LJ medium, 62 were obtained by middlebrook7H10 and MB bact, 58 by LJ and middlebrook7H10 and 58 by LJ medium, middlebrook7H10 and MB bact. Neither L J medium nor middlebrook 7H 1O medium could isolate mycobacteria exclusively. The average isolation time by L J, middlebrook 7H10 medium and MB BACT was 30.81 days,31.06 days and 18.70 days.