Neomycin robertson’s cooked meat medium (N.RCM) for the selective isolation of anaerobes.

ABSTRACT

As Robertson’s cooked meat medium (RCM) promotes the simultaneous multiplication of facultative anaerobes along with anaerobes, it may be interfered with the isolation rate of anaerobes. In the present study RCM was made selective to overcome this difficulty by the incorporation of Neomycin. The efficacy of modified RCM was evaluated by growing stock cultures of various anaerobes and aerobes well as by inoculating clinical specimen directly and comparing the results with routine RCM. Among the 160 stock cultures of aerobes 8 of the 28 neomycin resistant aerobes grew in N.RCM but none of the 132 neomycin sensitive aerobes. Out of the 150 clinical samples tested in the study,77 anaerobes and 97 aerobes were isolated from routine RCM whereas 89 anaerobes and 8 Neomycin resistant aerobes from NRCM (i.e. NRCM inhibited 91.7% of aerobes and gave an increased yield of 13.5% anaerobes).These findings suggest that NRCM can be employed to suppress the aerobes and at the same time to enhance the isolation of anaerobes.