Enhanced speed and sensitivity in the cultural diagnosis of pulmonary tuberculosis with a continuous automated mycobacterial liquid culture (CAMLiC) system

• Published in: Journal of medical microbiology Vol. 47; no. 6; pp. 547 - 553
• Main Authors: MAGEE, J. G, FREEMAN, R, BARRETT, A
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.06.1998; Society for General Microbiology
• Subjects: Bacterial diseases; Bacteriological methods and techniques used in bacteriology; Bacteriological Techniques - standards; Bacteriological Techniques - statistics & numerical data; Bacteriology; Biological and medical sciences; Centers for Disease Control and Prevention (U.S.); DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; Evaluation Studies as Topic; Fundamental and applied biological sciences. Psychology; Human bacterial diseases; Humans; Infectious diseases; Medical sciences; Microbiology; Molecular Probe Techniques; Mycobacterium tuberculosis - genetics; Mycobacterium tuberculosis - growth & development; Mycobacterium tuberculosis - isolation & purification; Reference Standards; Sensitivity and Specificity; Sputum - microbiology; Time Factors; Tuberculosis and atypical mycobacterial infections; Tuberculosis, Pulmonary - diagnosis; Tuberculosis, Pulmonary - microbiology; United States; United States; Performance evaluation; Human; Lung disease; Automation; Respiratory disease; Lung; Liquid medium; Mycobacterial infection; Species complex; Infection; Analysis method; Tuberculosis; Mycobacterium tuberculosis; Mycobacteriales; Bacteriosis; Mycobacteriaceae; Microorganism culture; Bacteria; Actinomycetes; Diagnosis
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/00222615-47-6-547

PHLS Regional Centre for Mycobacteriology, Newcastle Public Health Laboratory, Westgate Road, Newcastle upon Tyne NE4 6BE Corresponding author: Professor R. Freeman. Received April 10, 1997 Accepted October 27, 1997 A total of 2800 sputum samples referred for mycobacterial investigation was examined by both continuous automated mycobacterial liquid culture (CAMLiC) and conventional Loewenstein-Jensen culture (LJC). The CAMLiC system was more sensitive than LJC, detecting 188 (98.4%) of 191 of all mycobacteria found by one or both methods compared to 150–162 (78.5–84.8%) found by LJC (the range for LJC takes into account all potential ‘missed positives’ due to contamination). Figures for Mycobacterium tuberculosis complex (MTBC) organisms specifically were 133 (98.4%) of 135 for CAMLiC and 115–122 (85.2–90.4%) for LJC. Detectable growth of MTBC organisms in CAMLiC occurred at a mean of 13.4 days after inoculation (range 3–32; SD 6.49; mode 8 days); 65.4% of such isolates were 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 always present. The speed, sensitivity and labour-sparing technology (no manual intervention is necessary before identification or discard) of CAMLiC make it possible for many laboratories to approach the Centers for Disease and Prevention (CDC) standard for culture and identification in mycobacteriology without resort to direct DNA detection techniques and at a much lower cost.