Inhibitory effect of rubber on the growth of M. tuberculosis.

Rubber liners used in screw-cap bottles in Hong Kong were found to inhibit the growth of M. tuberculosis in culture media but not to exert any inhibitory effect on the bacilli in sputum. The British Standard for testing rubber used in transfusion equipment (BS: 2463) does not detect the inhibitory effect. It is recommended that rubber liners in the caps of bottles used for growing M. tuberculosis should be tested for cytotoxicity by a modification of the method described in British Standard 5213 or by the simple bacteriological tests described in this report.