Laboratory diagnosis of tuberculosis in a large pediatric hospital in Cambodia

Are scientific research outputs aligned with national policy makers' priorities? A case study of tuberculosis in Cambodia

With funding for tuberculosis (TB) research decreasing, and the high global disease burden persisting, there are calls for increased investment in TB research. However, justification of such investments is questionable, when translation of research outputs into policy and health care improvements remains a challenge for TB and other diseases. Using TB in Cambodia as a case study, we investigate how evidence needs of national policy makers are addressed by topics covered in research publications. We first conducted a systematic review to compile all studies on TB in Cambodia published since 2000. We then identified priority areas in which evidence for policy and programme planning are required from the perspective of key national TB control stakeholders. Finally, results from the literature review were analysed in relation to the priority research areas for national policy makers to assess overlap and highlight gaps in evidence. Priority research areas were: TB-HIV co-infection; childhood TB; multidrug resistant TB (MDR-TB); and universal and equitable access to quality diagnosis and treatment. On screening 1687 unique papers retrieved from our literature search, 253 were eligible publications focusing on TB in Cambodia. Of these, only 73 (29%) addressed one of the four priority research areas. Overall, 30 (11%), five (2%), seven (2%) and 37 (14%) studies reported findings relevant to TB-HIV, childhood TB, MDR-TB and access to quality diagnosis and treatment respectively. Our analysis shows that a small proportion of the research outputs in Cambodia address priority areas for informing policy and programme planning. This case study illustrates that there is substantial room for improvement in alignment between research outputs and evidence gaps that national policy makers would like to see addressed; better coordination between researchers, funders and policy makers' on identifying priority research topics may increase the relevance of research findings to health policies and programmes.

Molecular epidemiology of tuberculosis in Cambodian children

SUMMARY We analysed Mycobacterium tuberculosis strains from children, hospitalized from January 2004 to July 2008 in the largest paediatric hospital complex in Cambodia. Specimens were tested for drug susceptibility and genotypes. From the 260 children, 161 strains were available. The East African-Indian genotype family was the most common (59.0%), increasing in frequency with distance from the Phnom Penh area, while the frequency of the Beijing genotype family strains decreased. The drug resistance pattern showed a similar geographical gradient: lowest in the northwest (4.6%), intermediate in the central (17.1%), and highest in the southeastern (30.8%) parts of the country. Three children (1.9%) had multidrug-resistant tuberculosis. The Beijing genotype and streptomycin resistance were significantly associated (P < 0.001). As tuberculosis in children reflects recent transmission patterns in the community, multidrug resistance levels inform about the current quality of the tuberculosis programme.

The sensitivity of an interferon-γ release assay in microbiologically confirmed pediatric tuberculosis

This study aimed at determining the sensitivity of a whole blood interferon-γ release assay (IGRA) among children with microbiologically confirmed tuberculosis in a high-burden country. Children with a diagnosis of tuberculosis based on clinical and radiographic assessment were tested with an IGRA in addition to microbiologic examination of appropriate specimens for acid-fast bacilli, mycobacterial rRNA, and observation for growth of Mycobacterium tuberculosis on appropriate culture media. Of the 405 children with a clinical diagnosis of tuberculosis, 91 (22.5 %) had microbiologically confirmed tuberculosis, of whom 81 were tested with an IGRA. A positive result was obtained in 43 (sensitivity 53.1 %, 95 % confidence interval 42.3 to 63.6 %), uninfluenced by age, sex, or disease manifestation.

CONCLUSIONS

The sensitivity of a whole blood interferon-γ release assay in microbiologically confirmed pediatric tuberculosis was low. An IGRA cannot, thus, be used as rule-in test, but it might be useful to rule in tuberculosis among children in whom tuberculosis is notoriously difficult to confirm microbiologically.