ENHANCED SPEED AND SENSITIVITY IN THE CULTURAL DIAGNOSIS OF PULMONARYTUBERCULOSIS WITH A CONTINUOUS AUTOMATED MYCOBACTERIAL LIQUID CULTURE(CAMLIC) SYSTEM

A total of 2800 sputum samples referred for mycobacterial investigatio n was examined by both continuous automated mycobacterial liquid cultu re (CAMLiC) and conventional Loewenstein-Jensen culture (LJC). The CAM LiC system was more sensitive than LJC, detecting 188 (98.4%) of 191 o f all mycobacteria found by one or both methods compared to 150-162 (7 8.5-84.8%) found by LJC (the range for LJC takes into account all pote ntial `missed positives' due to contamination). Figures for Mycobacter ium tuberculosis complex (MTBC) organisms specifically were 133 (98.4% ) of 135 for CAMLiC and 115-122 (85.2-90.4%) for LJC. Detectable growt h of MTBC organisms in CAMLiC occurred at a mean of 13.4 days after in oculation (range 3-32; SD 6.49; mode 8 days); 65.4% of such isolates w ere detected within 14 days and 87.2% within 21 days. In 73 instances the MTBC status of the isolate was defined by gene probe on the day of growth detection. Sufficient biomass for valid gene probe assay was a lways present. The speed, sensitivity and labour-sparing technology (n o manual intervention is necessary before identification or discard) o f CAMLiC make it possible for many laboratories to approach the Center s for Disease and Prevention (CDC) standard for culture and identifica tion in mycobacteriology without resort to direct DNA detection techni ques and at a much lower cost.