Implementation of Thin Layer Agar for Mycobacterium culture in rural Kenya Médecins Sans Frontières

Context MSF support in the Hospital Since 2000 TB program ART program Integrated TB/HIV care TB culture laboratory in 2007 MSF support in the periphery Mobile clinic to 3 health centres Supply drugs 6 month regimen Homa Bay District Rural area 350,000 habitants 30% HIV prevalence

Context HIV patients 13,000 active patients on care 10,000 active patients on ART TB patients 1,500 new TB cases/year in District 400 new TB cases in Chest Clinic 80% HIV/TB co-infected

Methods Mycobacterium culture laboratory Techniques: Thin Layer Agar, Lowenstein-Jensen Routine activity since November 2007 Patients targeted Patients with cough >2 weeks and at least 2 negative sputum smear microscopy Retrospective study Period of the study: 15 th Nov 07 to 25 th July 08

Methods TLA technique: Solid culture (7H11) Petri dish (2 parts: 1 normal media; 1 with PNB) Incubator CO2 Reading with microscope Why this technique was chosen? Less logistics, maintenance, technical problems Lower cost Solid culture – less contamination expected, bio-safety

Comparison Mycobacterium culture techniques LJTLAMGITMODS MediumSolid Liquid Manual/AutomatedMMAM Equipment/Maintenance Time to positive (days) Sensitivity* - Smear Smear – Cost (USD) DST simultaneousNoYesNoYes * Int J Tuberc Lung Dis 10 (6): , Robledo et al

Results Culture result available in 365 patients: 50% negative, 31% positive, 19% contaminated 56% of culture positive had not started treatment Out of the 63 patients traced: 46% found and started on treatment 11% found and referred to the closest TB site 16% had died 13% could not be found 14% were still being traced

Results Patients missed through clinical algorithm and started on treatment after culture: 29 patients = 3.5 patients per month Patients diagnosed through clinical algorithm: 265 = 31.9 patients per month Proportion of TB patients diagnosed through culture: 10.9% Average time to get a positive result: 24 days

Results TLALJ Positive rate13%14% Negative rate62%69% Contamination rate24%17% Time to positive result 16 days26 days Culture results on smear negative samples from Nov 07 to Jul 08

Discussion - Achievements Almost a third of the TB suspect patients with negative smear were found positive by culture More than a half of them had been missed through clinical algorithm Culture had allowed the diagnosis of 11% of the total TB patients Time for positive results long but improving

Discussion - Challenges Cost of the laboratory Contamination rate currently high Electricity: back-up system required Keeping the laboratory clean: change shoes, windows closed, dust coats, etc. Training of the laboratory technicians is long BSC maintenance: technician coming from SA

Discussion - Challenges Expenses for TB culture laboratory (Jan 07-Sept 08) TOTAL expenses : € 17% 30% 25% 28% ConstructionEquipmentConsumableStaff 48,5 K € 83,6 k € 70 k € 77,8 k €

Conclusions Routine culture may have an important impact in the diagnosis of TB in a high HIV prevalence setting Is it cost-effective to set up a culture laboratory in an African rural context? Other alternatives? TLA has a potential in peripheral settings compared with others techniques (MGIT, LJ)