European Society of Mycobacteriology - Instituto Nacional de Saúde ...

PP-105
Implementation of liquid culture for tuberculosis
diagnosis in a remote setting: lessons learned
Pamela Hepple 1 , Jonathan Novoa-Cain 2 , Chris Cheruiyot 2 , Elvira Richter 3 , Koert Ritmeijer 4
1 - Manson Unit, Médecins sans Frontières, London, UK
2 - Médecins sans Frontières OCA South Sudan, Lokichoggio, Kenya
3 - Forschungszentrum Borstel, Nationales Referenzzentrum für Mykobakterien, D-23845 Borstel, Germany
4 - Médecins sans Frontières OCA, Amsterdam, the Netherlands
Issues
The diagnosis of tuberculosis (TB) in Médecins sans Frontières (MSF) projects is based on sputum smear microscopy,
which has low sensitivity. Following WHO recommendations, MSF established a TB liquid culture laboratory in
Lokichoggio, Kenya, processing samples from 4 South Sudan projects, for diagnosis of smear-negative and extra-pulmonary
(EP) TB and follow-up of patients.
Description
The manual MGIT (mycobacterial growth indicator tube, Becton Dickinson) system was used with Lowenstein-Jensen
media. One positive culture per patient was sent to Borstel Supranational Reference Laboratory, Germany for speciation
using the Hain Genotype Mycobacteria series and sequencing techniques.
From March 2007 to December 2008, sputum culture was performed for 64 diagnostic and 24 follow-up patients. Ten
EP samples were also cultured.
For diagnostic patients, of two smear-positives, one was culture-positive for both Mycobacterium tuberculosis (MTB) and
M. fortuitum, and one for M. fortuitum.
Eight of 62 (13%) smear-negatives were culture-positive for MTB complex (3 for MTB and 5 for MTBC) with nine (14%)
culture-positive for other identified mycobacteria; six (9%) grew unknown, not validly-described mycobacteria, and 39
(61%) were culture negative.
For follow-up patients, of seven smear-positives, one was culture-positive for MTB, one for M. intracellulare and one for
M. fortuitum complex, and four (57%) were culture-negative. Among the smear-negatives, eight of 17 (47%) were culturepositive,
four of which were unknown mycobacterial species, and four non-tuberculous mycobacteria (NTM). Nine (53%)
were culture-negative.
Samples from three EP patients of 10 grew mycobacteria, species unidentifiable.
In total, only 10 of 36 (28%) culture-positive patients grew mycobacteria from sputum which could be identified as MTB or MTBC.
Lessons learned
Due to the long turn-around time between sample production and species identification due to shipment issues (approximately
4-6 weeks), clinicians often did not wait for results before initiating or adjusting therapy. The high proportion
of NTM was difficult to interpret. The culture results had little clinical impact, and culture lab activities were suspended
in February 2009.
Recommendations
Future TB culture programmes require facilities for on-site speciation of mycobacteria or, if working with reference labs,
should minimize turn-around time to results by ensuring timely shipment of samples.
European Society of Mycobacteriology | 30 th Annual Congress | July 2009 | Porto - Portugal
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