Blood agar for the isolation of Mycobacterium tuberculosis

The present study suggests that the isolation of Mycobacteria tuberculosis on blood agar is not an anecdotal finding and that contamination of culture is not a frequent problem. Our results show that when desiccation is prevented by use of McCartney bottles instead of plates, blood agar can be a suitable alternative for the primary isolation of M. tuberculosis and may even be superior to egg-based agar. The blood-agar method requires no specific equipment and the same inoculated bottle allows for the isolation of both Mycobacterium tuberculosis and NTM. Blood-agar method requires only an incubator, basic equipment in clinical laboratory and aseptically collected sheep blood, antifungals and antibiotics which can be readily obtained, provided appropriate micro-biological safety measures are in place to counter the highly infectious nature of Mtb. Blood agar is not only inexpensive, but is also as sensitive and as rapid as the reference automated method used in developed countries. Hence, our present study can conclude and recommend ordinary blood agar as a rapid, reliable and cost-effective method for culture and isolation of Mycobacterium species from various clinical specimens.