The use of variable-number tandem-repeat mycobacterial interspersed repetitive unit typing to identify laboratory cross-contamination with Mycobacterium tuberculosis.

A retrospective study including 515 Mycobacterium tuberculosis isolates from 215 patients was conducted to investigate possible laboratory contamination with M. tuberculosis over a 1-year period in a university hospital. All cultures underwent variable-number tandem-repeat (VNTR) typing. Cultures suspected of being contaminated in the VNTR analysis and possible sources of contamination underwent mycobacterial interspersed repetitive unit (MIRU) typing further. Overall, 8 (3.7%) cases of 215 patients were considered possible false-positives. Five (2.3%) cultures might be contaminated during initial batching processing, and 1 (0.5%) and 4 (1.9%) cultures of them were further classified as presumed and possible cases, respectively, of cross-contamination on clinical grounds. Three (1.4%) cultures might be contaminated by cultures that had been processed in species identification procedures in the same laminar-flow hood. The 2-step strategy using VNTR and MIRU analyses in combination in this study appears to be a valuable means for the study of false-positive cultures.

[1]  P. Butcher,et al.  Estimation of the Rate of Unrecognized Cross-Contamination with Mycobacterium tuberculosis in London Microbiology Laboratories , 2002, Journal of Clinical Microbiology.

[2]  S. Gillespie,et al.  Molecular methods for Mycobacterium tuberculosis strain typing: a users guide. , 2003, Journal of applied microbiology.

[3]  P. Hawkey,et al.  Rapid Identification of Laboratory Contamination withMycobacterium tuberculosis Using Variable Number Tandem Repeat Analysis , 2001, Journal of Clinical Microbiology.

[4]  J. Bauer,et al.  False-positive results from cultures of Mycobacterium tuberculosis due to laboratory cross-contamination confirmed by restriction fragment length polymorphism , 1997, Journal of clinical microbiology.

[5]  R. Frothingham,et al.  Genetic diversity in the Mycobacterium tuberculosis complex based on variable numbers of tandem DNA repeats. , 1998, Microbiology.

[6]  C. Braden,et al.  A Prospective, Multicenter Study of Laboratory Cross-Contamination of Mycobacterium tuberculosis Cultures , 2002, Emerging infectious diseases.

[7]  Ellen Jo Baron,et al.  Manual of clinical microbiology , 1975 .

[8]  G. Schoolnik,et al.  Molecular strain typing of Mycobacterium tuberculosis to confirm cross-contamination in the mycobacteriology laboratory and modification of procedures to minimize occurrence of false-positive cultures , 1993, Journal of clinical microbiology.

[9]  Albert Balows,et al.  Manual of Clinical Microbiology, 7th ed. , 2000 .

[10]  R. G. Hewinson,et al.  Discrimination of Mycobacterium tuberculosis complex bacteria using novel VNTR-PCR targets. , 2002, Microbiology.

[11]  R. Reves,et al.  Review of false-positive cultures for Mycobacterium tuberculosis and recommendations for avoiding unnecessary treatment. , 2000, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[12]  W. Stead,et al.  Retrospective detection of laboratory cross-contamination of Mycobacterium tuberculosis cultures with use of DNA fingerprint analysis. , 1997, Clinical infectious diseases : an official publication of the Infectious Diseases Society of America.

[13]  R. Frothingham,et al.  Comparison of Methods Based on Different Molecular Epidemiological Markers for Typing of Mycobacterium tuberculosis Complex Strains: Interlaboratory Study of Discriminatory Power and Reproducibility , 1999, Journal of Clinical Microbiology.

[14]  J. T. Crawford,et al.  Variable-Number Tandem Repeat Typing of Mycobacterium tuberculosis Isolates with Low Copy Numbers of IS6110 by Using Mycobacterial Interspersed Repetitive Units , 2002, Journal of Clinical Microbiology.

[15]  S. Gillespie,et al.  Comparison of Variable Number Tandem Repeat and IS6110-Restriction Fragment Length Polymorphism Analyses for Discrimination of High- and Low-Copy-Number IS6110 Mycobacterium tuberculosis Isolates , 2001, Journal of Clinical Microbiology.

[16]  J. Musser,et al.  Extensive Cross-Contamination of Specimens withMycobacterium tuberculosis in a Reference Laboratory , 1999, Journal of Clinical Microbiology.

[17]  C. Locht,et al.  High-resolution minisatellite-based typing as a portable approach to global analysis of Mycobacterium tuberculosis molecular epidemiology. , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[18]  E. Nardell,et al.  Estimated Costs of False Laboratory Diagnoses of Tuberculosis in Three Patients , 2002, Emerging infectious diseases.

[19]  M. Wilson,et al.  The effect of changes in laboratory practices on the rate of false-positive cultures for Mycobacterium tuberculosis. , 2001, Archives of pathology & laboratory medicine.

[20]  R. Reves,et al.  The incidence of false-positive cultures for Mycobacterium tuberculosis. , 1997, American journal of respiratory and critical care medicine.

[21]  Philip Supply,et al.  Automated High-Throughput Genotyping for Study of Global Epidemiology of Mycobacterium tuberculosis Based on Mycobacterial Interspersed Repetitive Units , 2001, Journal of Clinical Microbiology.

[22]  D. van Soolingen,et al.  Investigation of cross contamination in a Mycobacterium tuberculosis laboratory using IS6110 DNA fingerprinting. , 1998, The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease.

[23]  P. Hawkey,et al.  Mycobacterial Interspersed Repetitive Unit Typing of Mycobacterium tuberculosis Compared to IS6110-Based Restriction Fragment Length Polymorphism Analysis for Investigation of Apparently Clustered Cases of Tuberculosis , 2003, Journal of Clinical Microbiology.

[24]  Philip Supply,et al.  Variable human minisatellite‐like regions in the Mycobacterium tuberculosis genome , 2000, Molecular microbiology.

[25]  D. van Soolingen,et al.  False-Positive Mycobacterium tuberculosis Cultures in 44 Laboratories in The Netherlands (1993 to 2000): Incidence, Risk Factors, and Consequences , 2002, Journal of Clinical Microbiology.

[26]  Y. Jin,et al.  Comparison of the MB/BacT and BACTEC MGIT 960 system for recovery of mycobacteria from clinical specimens. , 2000, Diagnostic microbiology and infectious disease.