TY - JOUR
T1 - Infrequent MODS TB culture cross-contamination in a high-burden resource-poor setting
AU - Moore, David A.J.
AU - Caviedes, Luz
AU - Gilman, Robert H.
AU - Coronel, Jorge
AU - Arenas, Fanny
AU - LaChira, Doris
AU - Salazar, Cayo
AU - Carlos Saravia, Juan
AU - Oberhelman, Richard A.
AU - Hollm-Delgado, Maria Graciela
AU - Escombe, A. Roderick
AU - Evans, Carlton A.W.
AU - Friedland, Jon S.
PY - 2006/9
Y1 - 2006/9
N2 - One obstacle to wider use of rapid liquid culture-based tuberculosis diagnostics such as the microscopic observation drug susceptibility (MODS) assay is concern about cross-contamination. We investigated the rate of laboratory cross-contamination in MODS, automated MBBacT, and Lowenstein-Jensen (LJ) cultures performed in parallel, through triangulation of microbiologic (reculturing stored samples), molecular (spoligotype/RFLP), and clinical epidemiologic data. At least 1 culture was positive for Mycobacterium tuberculosis for 362 (11%) of 3416 samples; 53 were regarded as potential cross-contamination suspects. Cross-contamination accounted for 17 false-positive cultures from 14 samples representing 0.41% (14/3416) and 0.17% (17/10 248) of samples and cultures, respectively. Positive predictive values for MODS, MBBacT (bioMérieux, Durham, NC), and LJ were 99.1%, 98.7%, and 99.7%, and specificity was 99.9% for all 3. Low rates of cross-contamination are achievable in mycobacterial laboratories in resource-poor settings even when a large proportion of samples are infectious and highly sensitive liquid culture-based diagnostics such as MODS are used.
AB - One obstacle to wider use of rapid liquid culture-based tuberculosis diagnostics such as the microscopic observation drug susceptibility (MODS) assay is concern about cross-contamination. We investigated the rate of laboratory cross-contamination in MODS, automated MBBacT, and Lowenstein-Jensen (LJ) cultures performed in parallel, through triangulation of microbiologic (reculturing stored samples), molecular (spoligotype/RFLP), and clinical epidemiologic data. At least 1 culture was positive for Mycobacterium tuberculosis for 362 (11%) of 3416 samples; 53 were regarded as potential cross-contamination suspects. Cross-contamination accounted for 17 false-positive cultures from 14 samples representing 0.41% (14/3416) and 0.17% (17/10 248) of samples and cultures, respectively. Positive predictive values for MODS, MBBacT (bioMérieux, Durham, NC), and LJ were 99.1%, 98.7%, and 99.7%, and specificity was 99.9% for all 3. Low rates of cross-contamination are achievable in mycobacterial laboratories in resource-poor settings even when a large proportion of samples are infectious and highly sensitive liquid culture-based diagnostics such as MODS are used.
KW - Cross-contamination
KW - MODS
KW - Microbacterial culture
KW - Microscopic observation drug susceptability assay
KW - Multidrug resistance
KW - Tubercolosis
UR - http://www.scopus.com/inward/record.url?scp=33748060844&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748060844&partnerID=8YFLogxK
U2 - 10.1016/j.diagmicrobio.2006.03.009
DO - 10.1016/j.diagmicrobio.2006.03.009
M3 - Article
C2 - 16678991
AN - SCOPUS:33748060844
SN - 0732-8893
VL - 56
SP - 35
EP - 43
JO - Diagnostic Microbiology and Infectious Disease
JF - Diagnostic Microbiology and Infectious Disease
IS - 1
ER -