TB Notes Newsletter
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No. 4, 2006
Laboratory Update
New Technologies Unveiled at the 2006
National TB Controllers’ Workshop
At the June 2006 meeting of the National
Tuberculosis Controllers’ Association in Atlanta, GA,
representatives of two state public health laboratories
presented exciting new methods for detecting drug-resistant
tuberculosis (TB) in hours or days rather than the month that
had until recently been required.
At a plenary session and in a poster
presentation, Dr. Max Salfinger, then with the New York State
Department of Health, presented Wadsworth Center’s evaluation of
the Genotype MTBDR Assay from Hain Lifesciences in Nehren,
Germany. In a breakout session, Dr. Edward Desmond of the
California Department of Health Services described the
performance parameters and public health impact of a molecular
beacons assay that had been developed in the California
laboratory. Both methods are used directly with acid-fast
smear-positive clinical specimens, and can give a result within
1 or 2 days after the specimen arrives in the laboratory.
In an era when strains of the
Mycobacterium tuberculosis complex with extensive drug
resistance are emerging (see MMWR 2006; 55:301-305), detection
of multidrug-resistant (MDR) strains within 48 hours can have an
important public health impact by enabling patients to be put on
an effective regimen much sooner. The Genotype MTBDR assay will
be submitted for approval by the US Food and Drug Administration
in the near future. The molecular beacons assay is not yet a
commercial product, but has been extensively studied and used by
the California laboratory for 3 years. Dr. Desmond reported that
it has a high level of agreement (96%–97%) with conventional
drug-susceptibility testing. He also indicated that it has
proven useful in many circumstances, including cases in which
drug resistance is suspected, cases in which conventional
drug-susceptibility testing is slow or impossible, and
high-impact cases in which patients are critically ill or large
numbers of patients could be affected by quick detection of drug
resistance.
More details regarding these assays were
provided in the following presentations and publications:
- Somoskovi A, Dormandy J, Rivenburg J,
and Salfinger M. Rapid direct detection and susceptibility
testing of the Mycobacterium tuberculosis complex for isoniazid
and rifampin in smear positive clinical specimens by the PCR-based
Genotype MTBDR Assay. Poster at the 2006 National TB Controllers
Workshop [Readers who would like to receive a copy of the poster
may write to max.salfinger@doh.state.fl.us
- Lin S-Y, Wenger J, Mase S, Agraz R,
Raftery A, and Desmond E. 2005. Utilization of molecular beacons
for rapid detection of MDR TB in a public health setting.
Abstracts of the 2005 Interscience Conference on Antimicrobial
Agents and Chemotherapy. [Readers who would like a copy of the
poster may contact Ed Desmond at
Edesmond@dhs.ca.gov]
- Lin,S-Y, Probert W, Lo M, and Desmond
E. Rapid detection of isoniazid and rifampin resistance
mutations in Mycobacterium tuberculosis complex from cultures or
smear-positive sputa by molecular beacons.
Journal of Clinical
Microbiology 2004; 42(9): 4204-4208.
—Reported by Anthony Tran,
MPH, MT (ASCP)
Association of Public Health Laboratories
On behalf of the APHL TB Steering Committee |
