The colonising flora in sputum specimens of tuberculosis patients hampers primary isolation of tubercle bacilli. Some of these survive the action of even a strong alkali like 4% NaOH when processed by modified Petroff’s method. The mechanical pressure exerted during centrifugation and the chemical pressure experienced when sputum specimens are processed, leave the tubercle bacilli in the sputum unsuitable for rapid detection especially in phage based assays. Thus, growing Mycobacterium tuberculosis in broth, at least overnight, is mandatory for allowing the tubercle bacilli to recoup. During this time the surviving colonising flora grow faster and overgrow tubercle bacilli interfering with TB diagnosis. Supplementation with antibiotics to overcome this problem affects the viability of tubercle bacilli to some extent. In the present study normal flora surviving the action of 4% NaOH was isolated and characterized. Phages capable of killing 14 organisms representing this normal flora were isolated from soil and sewage samples and characterised. A novel and bio-friendly approach to treat sputum samples with a cocktail of three phages capable of killing most of the 14 representative organisms and not infecting mycobacteria is experimented to control the overgrowth of colonizing bacteria in broth culture. While 26 of the 100 sputum samples processed by modified Petroff’s procedure showed growth of colonising flora on blood agar, all of them when grown in broth overnight showed mixed, confluent growth. The addition of phagebiotics controlled them in all showing a significant reduction in colony forming units but resulting in few discrete colonies
in 54 samples. Isolation of phages capable of controlling these surviving organisms and including them in the phagebiotics mixture should lead to the control of colonising bacteria effectively.
More abstracts about the Phage cocktail to control the exponential growth of normal flora in processed sputum specimens grown