Mycobacterium tuberculosis

According to the World Health Organization (WHO), tuberculosis (TB) is the greatest infectious killer worldwide after HIV/AIDS. Most cases of the disease can be treated by isoniazid and rifampicin, two powerful anti-TB drugs.

Unfortunately, a drug resistant strain has emerged which does not respond to these drugs. Even worse, a new strain called XTR TB (extensively drug resistant TB) is not only resistant to isoniazid and rifampin but also to fluoroquinolone and ≥1 of 3 injectable second-line drugs (amikacin, kanamycin, or capreomycin).

In this post, the battle against TB is described by Dr. Daniel Murphy, the medical director of the Bairo Pite Clinic in Timor-Leste. We also share five ways microbiology laboratories can help fight TB.

Bairo Pite Clinic in Timor-Leste

(Written by Dr. Daniel Murphy)

I live, eat, breathe, sleep, and dream TB. An average of five people a day present with hemoptysis (spitting up blood or blood-tinged sputum or the respiratory tract) at our clinic. The lab finds 300 Zeihl-Neilson positive smears each year. At the Bairo Pite Clinic in Timor-Leste, we see more TB than any other clinic in the Asia/Pacific region. Timor-Leste is located about 1000 miles east of Bali.

Recently my cousin, Laurie Kundrat, a Technical Specialist at Microbiologics, came for a visit. We traveled deep into the interior of this beautiful newly independent country and saw first-hand exactly what conditions predispose to this devastating epidemic. Quite simply, it is high population density that puts people near each other for extended time periods during the equatorial 12 hour nights. Analyzing in more depth shows that grinding poverty also contributes heavily. And finally, we can conclude that an ever widening gap between rich and poor provide little to no health care for the less privileged in many parts of the world.

Dr. Daniel Murphy (center) with his team at the Bairo Pite Clinic

Without a doubt it would be hard to imagine a more difficult pathologic foe. Mycobacterium tuberculosis transmits by air quite readily. It can shut down metabolism to a dormant stage lasting indefinitely with the constant threat of reactivation if conditions are favorable. Its thick lipid coat protects from effectiveness of any vaccination. In one-third of cases it festers in pulmonary cavities not killing but effectively transmitting with each and every cough.

While antibiotics have been available for 50 years, we find it ever more difficult to keep pace with this master pathogen as it constantly mutates into more sophisticated resistant forms. A desperately impoverished Papua New Guinea now spends half its TB budget just trying to deal with multi-drug resistant strains.

Some progress is being made. We now have a Gene Xpert PCR machine, the only one on the island for a population of more than one million. We can now detect 10 bacteria/ml of sputum rather than the 10,000 bacteria needed to turn a smear positive. An added benefit is the rapid detection of resistant strains through identification of the well- defined causative mutations. Global Fund contributes to national programs throughout the world.We actively search for cases. We organize community monitors. We boost adherence to treatment as much as possible. Still frustration permeates all our deliberations. We are dealing with the “sergeant of the men of death.” It seems that inevitably TB always wins.

See Dr. Murphy’s biography at the end of the post

The Lab’s Role in Fighting Tuberculosis

(Written by Laurie Kundrat, Microbiologics Technical Specialist)

The microbiology laboratory is a key player in the fight against TB. WHO believes quality-assured bacteriology can reduce tuberculosis by ensuring early case detection and diagnosis. Here are five ways in which laboratories can help in the fight against TB:

1. Provide safe working conditions for laboratories personnel. Because tuberculosis has a low infective dose (the 50% infective dose is less than 10 AFB), the Centers for Disease Control and Prevention (CDC) recommends laboratories follow biosafety level (BSL) 3 precautions if they are performing identification or susceptibility testing of cultures that may contain MTBC. BSL 2 laboratories and should only be used for non-aerosol manipulations such as the preparation of AFB smears from patient specimens. See CDC’s publication, Biosafety in Microbiological and Biomedical Laboratories.

2. Report acid-fast bacteria smear results within 24 hours of receipt of a clinical specimen.

3. Improve turn-around-time by using nucleic acid amplification methods for identification of tuberculosis. In a publication titled Report of an Expert Consultation on the Uses of Nucleic Acid Amplification Tests for the Diagnosis of Tuberculosis, the CDC says NAA testing can be beneficial because earlier diagnosis leads to earlier initiation of treatment and a reduced period. Positive and negative controls should be used in addition to internal controls for detecting amplification inhibition and contamination between specimens. WHO not only recommends molecular methods for rapid identification of M. tuberculosis, but also recommends the use of molecular drug susceptibility tests (DST) for screening of multidrug-resistant TB.

4. Train new employees. For example, teach personnel how to avoid cross-contamination. It can occur from the generation of aerosols, specimen carry-over, and contaminated reagents and water.

5. Run positive and negative controls on new lots of media, reagents, and stains.

Looking for  Mycobacterium tuberculosis controls? Click here to find the right format for your lab.

Biography

Dr. Daniel Murphy received his MD from the University of Iowa. He has been working in Timor-Leste since 1998 and is committed to providing free, essential healthcare for the poor and underprivileged people of Timor-Leste. He is the founder, medical director and serves on the board of directors of the Bairo Pite Clinic.

Daniel Murphy’s day begins at 8:00am and finishes well into the night. Treating widespread diseases including tuberculosis (TB), malaria, dengue fever, pneumonia, diarrhoea, hepatitis, encephalitis, yaws, leprosy and HIV, Dr. Murphy also delivers preventive medicine to men, women and children and assists in the delivery of up to 100 babies every month.

Daniel Murphy and the Bairo Pite Clinic received the country’s highest honor, the Medalha do Merito de Timor-Leste (Medal of Merit) for services to Timor-Leste. Dr. Murphy has also received the Distinguished Alumnus Award, University of Iowa School of Medicine and the Sergio de Melo Award, in recognition of his years of service to the people of Timor-Leste.

More information about the Bairo Pite Clinic can be found at bairopiteclinic.org or follow the Bairo Pite Clinic on Facebook.