Projects

Molecular Epidemiology of Mycobacterium tuberculosis in Kiribati

Tuberculosis (TB) remains an important infectious disease globally, in 2010 in the Pacific nation of Kiribati, case notification is 370 per 100,000, 60 times that of Australia.

But risk factors for transmission are poorly understood. We investigated molecular and epidemiological factors associated with the ongoing TB epidemic in Kiribati.

Sputum and structured questionnaires were collected from patients presenting with TB symptoms at the central hospital in Kiribati.

Sputum was cultured, isolates genotyped using three methods (RFLP, MIRU-VNTR and spoligotyping) and drug susceptibility testing performed.

This will be the first report of prevailing TB strains in Kiribati. These results will identify prevention approached that should be adopted in Kiribati to reduce the future impact of TB.

Published in PLoS ONE Journal

Tuberculosis incidence rates in Kiribati are among the highest in the Western Pacific region, however the diversity of circulating Mycobacterium tuberculosis strains is largely unknown.

We embarked on a project in collaboration with the Secretariat of the Pacific Community (New Caledonia), Pasteur Institute (New Caledonia) and National Reference Center for Mycobacterium (Germany), to collect data that could be used to inform local public health policy.

Tuberculosis strains cultured from patients living in Kiribati islands between November 2007 and October 2009 were genotyped (using four widely used genotyping methods; IS6110 typing, spoligotyping, 24-loci MIRU-VNTR and SNP typing) and patient information was collected.

TB was cultured from 73 of the 163 recruited patients. Using genotype methods we were able to identify seven phylogenetic lineages (different groups of Mtb strains) including a novel Kiribati strain never identified before.

The Beijing strain lineage that has been linked to drug-resistance in other countries around the world, was most commonly found in the Kiribati cohort (49 per cent). Although we found little evidence of drug resistance in our study sample, we identified that the Beijing strains were linked to over-crowded living conditions in our study population. Furthermore, many strains in our cohort (59 per cent based on IS6110 typing of all strains) clustered, suggesting that there is ongoing transmission of TB in the local community.

In conclusion, we suggest an enhanced case finding among close contacts and continued supervised treatment of all identified cases using standard first-line drugs can assist in reducing the TB burden in Kiribati.

Publications

2013

Collaborators

  • Stefan Niemann - National Reference Centre for Mycobateria, Forschungszentrum, Borstel, Germany
  • Helen Cox - Centre for Virology, Burnet Institute and Department of Medicine, Monash University, Victoria, Australia
  • Janet O'Connor - Secretariat of the Pacific Community, Noumea, New Caledonia
  • Bereka Reiher - TB Clinic, Tunguru Central Hospital, Tarawa, Kiribati
  • Regis Goursaud - Department of Microbiology, Pasteur Institute, Noumea, New Caledonia
  • Clement Malau - Department of Health, Port Moresby, Papua New Guinea

Health Issue

Contact Details

For any general enquiries relating to this project, please contact:

Professor Suzanne Crowe AM

Burnet Associate

Telephone

+61392822194

Email

suzanne.crowe@burnet.edu.au