Overview

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Tuberculosis (TB) continues to be one of the most serious challenges facing health systems in developing countries, with an estimated 9.2 million new cases and 1.7 million deaths in 2006¹. The incidence of multidrug-resistant (MDR) TB, defined as resistance to the most important first-line drugs rifampicin and isoniazid, has been increasing with an estimated 489,139 cases emerging in 2006². The increase in MDR-TB, along with reports of extensively drug-resistant (XDR) TB, with additional resistance to the most important second-line drugs, has led to the development of a global response plan to address the serious threat of drug-resistant TB³. An important component of this plan calls for significant expansion of TB diagnostic laboratory capacity, upon which the detection of MDR-TB and XDR-TB depends. The required increase in the scope of laboratory services in high burden countries has been estimated to include up to 13,000 centers for smear microscopy; 130 advanced diagnostic centers for culture and drug susceptibility testing (DST), five national referral labs, and an increase in the number of supranational reference labs¹. The challenge of MDR- and XDR-TB is further amplified in countries where there is also a high rate of HIV infection.

FIND was launched at the World Health Assembly in 2003 to accelerate and drive the development process of diagnostic tests for poverty-related diseases, and to evaluate and demonstrate the efficacy and effectiveness of these diagnostic tools under the typical field settings in developing countries. The tools that FIND has worked on include: liquid culture for TB and DST; a rapid immunoassay for species identification of M. tuberculosis complex strains from culture isolates, and a molecular line probe assay (LPA) for detection of isoniazid (NH) and rifampicin (RIF) resistance (MDR-TB) within 48 hours.

Smear staining corner in a laboratory in Dharavi slums

Laboratory in the DRC before refurbishment

The evidence gathered from clinical trials with these technologies has been submitted by FIND to the Strategic Advisory Committee of the Stop TB Partnership Department of the World Health Organization (WHO). Following a systematic review of data on these assays by independent experts, WHO has endorsed these technologies for use in TB laboratories in developing countries^4,5. However, rolling out these new technologies on a wider scale will only be feasible if the laboratories in high burden countries are strengthened and prepared in terms of infrastructure, quality assurance (QA) systems, standard operating procedures (SOPs), and training. Realizing these limitations, FIND has rapidly established a laboratory support programme to demonstrate and to document the steps needed to translate policy into practice.

The first laboratory upgrading project launched by FIND, together with assorted partners, was in the Kingdom of Lesotho. This represented an early opportunity to respond to an urgent need to establish TB diagnostic capacity. Lesotho, a small, landlocked, country with limited natural resources and a population of approximately 2 million people, is affected by both the HIV and TB epidemics with an estimated HIV prevalence of 25% among adults aged 15-49⁶ and a case notification rate of 605 cases of TB per 100,000 population⁷. As of 2006, however, TB diagnostic capacity within the National TB Programme (NTP) was limited to smear microscopy which was performed in 17 microscopy centers without an adequate QA program. All clinical specimens requiring TB culture and DST had to be sent out of the country at a high cost to laboratories in either South Africa or the U.S. In October 2006, the Minister of Health (MOH) of Lesotho requested assistance, through the WHO, for strengthening TB diagnostic services. This became FIND's first laboratory support project with other partners.

Figure 1: Integration of laboratory services (courtesy of John Nkengasong)

Integration of molecular biologic diagnostic services for tuberculosis and HIV

Introduction

Resource limited settings face numerous challenges due to a lack of integrated and well-established laboratory systems. This poses a serious challenge in scaling up laboratory support for HIV, malaria, tuberculosis or opportunistic infectious disease programs.

It was recognized in the Maputo Declaration of the World Health Organization that in order to improve and sustain access to laboratory services there must be an integration of laboratory support for HIV, tuberculosis, and malaria programs. The goal of such an effort should be to establish laboratory services as part of the greater health system from a public health perspective. Such efforts need to include the integration of adequate leadership, human resources, training, national laboratory policy, strategic planning, infrastructure, supply chain and quality management activities (Figure 1).

FIND, which was established as a spinoff from the WHO/Special Programme for Research and Training in Tropical Diseases six years ago, works in partnership with public and private sector agencies to develop, evaluate, and accelerate the implementation of diagnostics for diseases of poverty, including tuberculosis, malaria, and sleeping sickness.

We were among the first organizations to endorse the goals of the Maputo Declaration and incorporate them into our field activities. One of the most important areas for potential coordination of laboratory techniques is the integrated use of molecular methods or platforms to fully utilize the rapidity, accuracy and safety (does not require viable and highly infectious material) that such methods can provide.

The Lesotho model to integrate molecular tuberculosis and HIV diagnostic services at central level

At the request of the Ministry of Health in Lesotho, and working with partners, FIND engaged in a project to strengthen TB diagnostic services by providing a long-term, on-site consultant to work in close collaboration with the National TB Reference Laboratory (NTRL) and NTP. The performance of sputum microscopy has been brought up to quality standards with training modules and a Quality Assurance scheme has been established. In parallel, the NTRL has been renovated, with the creation of a BSL 2+ facility that meets the requirements recommended by WHO for handling liquid TB culture. TB solid culture and DST have been implemented, with EQA provided by the WHO Supra National Reference Laboratory of the South Africa Medical Research Council located in Pretoria. Subsequently, liquid culture for TB and susceptibility testing (DST), along with rapid immunoassay-based species identification, has been implemented. Reporting on isolation and contamination rates for solid culture on Lowenstein Jensen media and TB liquid culture on the BACTEC™ MGIT 960™ TB System has been available since December 2007.

In mid-2008, activities to prepare for the introduction of the line probe assay for detection of INH and RIF resistance began with the construction of a clean-room facility for molecular biology. The introduction of the assay and training of laboratory staff took place in October 2008. Through these efforts, the capacity of the NTRL in Lesotho has increased dramatically from an estimated 600 TB smears and five TB cultures per month to more than 2500 smears and 700 cultures per month by June 2008. An international team led by WHO carried out a site visit in early July 2008 and devised a work program to further update the standard operating procedures (SOPs) based on WHO specifications.

In February 2009, FIND and GAP-CDC/PEPFAR developed a short term plan to introduce early infant diagnosis (EID) of HIV by molecular methods by April 2009. The EID technique will be implemented in the TB Molecular laboratory and will be performed by the team of this unit along with the line probe assay for MDR-TB (Figure 2).

Figure 2: The Lesotho model for integration of molecular services for HIV and tuberculosis

The Ethiopian model to integrate molecular tuberculosis and HIV diagnostic services at central and regional level

Ethiopia is one of the high burden countries with tuberculosis. The country has requested FIND to support the establishment of the MGIT liquid culture system, the Capilia rapid identification system and the GenoType MTBDRplus line probe assay-based molecular system for rapid detection of MDR tuberculosis. To guide these activities, a Memorandum of Understanding was signed by the Ethiopian Health and Nutrition Research Institute (EHNRI) and FIND in October 2007.

In collaboration with EHNRI, CDC-Ethiopia, the International Laboratory Branch (ILB) at GAP-CDC in Atlanta and other partners (Johns Hopkins University), FIND has developed a comprehensive work plan to strengthen TB laboratory services at two central (ENHRI and St. Peter`s Hospital) and four regional level laboratories.

In order to facilitate these objectives two central laboratories are being upgraded with the support of CDC-Ethiopia at EHNRI and Johns Hopkins University at St. Peter`s Hospital. Appropriate renovation of the four regional laboratories is expected to be completed by the end of February 2009. In addition, FIND posted one full-time international consultant and supplied these laboratories with MGIT instruments and reagents, GenoType MTBDRplus tests and instruments, and Capilia rapid identification tests.

In January 2009, three technicians with previous molecular experience on HIV viral load testing were trained in the scope of a 5-day comprehensive practical course with the GenoType MTBDRplus line probe assay-based molecular system for rapid detection of MDR tuberculosis from ENHRI and St. Peter`s Hospital in Addis Ababa. St. Peter`s Hospital is a central hospital for potential treatment failure tuberculosis cases as well as, HIV patients. Earlier, molecular viral load testing for HIV had been established in this hospital but due to lack of proper infrastructure the service had to be stopped. In collaboration with the hospital and Johns Hopkins University at Baltimore, FIND initiated the re-introduction of molecular viral load testing in the newly established tuberculosis laboratory’s molecular unit. The line probe assay for tuberculosis and viral load testing will be preformed by the same group of molecular technicians. The opening of the facility is planned for March 2009.

In collaboration with ENHRI, FIND is working on an implementation plan to train representatives of four regional laboratories that are already providing molecular viral load testing for HIV, with GenoType MTBDRplus line probe assay-based molecular system for rapid detection of MDR tuberculosis. After completion of the renovation of these regional laboratories, FIND expects to implement the line probe assay for tuberculosis in these facilities by the end of 2009 (Figure 3).

Figure 3: Integration of tuberculosis and HIV laboratory diagnostic services in Ethiopia at regional level

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References

1,7. World Health Organization Global Tuberculosis Control: Surveillance, Planning, Financing: WHO Report 2008. (World Health Organization: Geneva, Switzerland)
2. The WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance Anti-Tuberculosis Drug Resistance in the World. Fourth Global Report. (World Health Organization: 2008)
3. World Health Organization The Global MDR-TB & XDR-TB Response Plan, 2007-2008. (2007).
4. World Health Organization WHO | New WHO policies. The use of liquid medium for culture and DST. Policy
5. World Health Organization Molecular Line Probe Assays For Rapid Screening Of Patients At Risk Of Multidrug-Resistant Tuberculosis (MDR-TB). Policy Statement. (2008).
6. Epidemiological Fact Sheet on HIV and AIDS. Core data on epidemiology and response. Lesotho. 2008 Update. UNAIDS/WHO/UNICEF Epidemiological fact sheets on HIV and AIDS.