Characterisation of Mycobacterium tuberculosis isolates lacking IS6110 in Viet Nam.

SETTING: The molecular diagnosis of tuberculosis (TB) in Viet Nam is often based on the detection of insertion sequence (IS) 6110 in Mycobacterium tuberculosis. However, 8-11% of M. tuberculosis strains in South-East Asia do not contain this target and this undermines the validity of these molecular tests. OBJECTIVE: We quantified the frequency of M. tuberculosis strains lacking IS6110 in rural Viet Nam and studied their epidemiological and clinical characteristics. DESIGN: Consecutively diagnosed adult TB patients in rural Southern Viet Nam submitted two sputum samples for culture, IS6110 restriction fragment length polymorphism (RFLP) spoligotyping and 15-loci variable number tandem repeat typing. Polymerase chain reaction (PCR) was performed to confirm the absence of IS6110 elements in strains lacking IS6110 hybridisation in RFLP. RESULTS: Among 2664 TB patient isolates examined, 109 (4.1%) had no IS6110 element. Compared to other strains, these no-copy strains were less often resistant to anti-tuberculosis drugs, particularly to streptomycin (adjusted OR 0.2, 95%CI 0.1-0.5), and showed significant geographic variation. No associations with TB history or demographic factors were found. CONCLUSIONS: Strains without the IS6110 target pose a problem in Viet Nam as regards false-negative molecular TB diagnosis in PCR. Compared to other strains circulating in Viet Nam, no-copy strains are more susceptible to anti-tuberculosis drugs.

The ethics of a clinical trial when the protocol clashes with international guidelines.

Due to their nature and complexity, clinical trials often take some time to launch after the protocol has been designed and ethics approval obtained. During this time, there may be changes in international treatment guidelines and recommendations that result in a conflict between study protocol and recommended international best practice. Here, we describe the situation that arose in a pharmacokinetic study on the use of two different doses of rifabutin in patients with human immunodeficiency virus-associated tuberculosis who initiated antiretroviral therapy (ART) with a lopinavir-ritonavir-based regimen in South Africa and Viet Nam. The study protocol specified that ART should be started 10 weeks after the start of anti-tuberculosis treatment. The study in South Africa was approved in June 2008, went ahead as scheduled and was completed in August 2010. The study in Viet Nam was approved in October 2008 and was started in June 2010. A few weeks later, the World Health Organization released their 2010 guidelines for adult ART; one of its strong recommendations (with moderate quality of evidence) was that ART should be started 2-8 weeks after the start of anti-tuberculosis treatment. Emerging scientific evidence also supported this recommendation. The investigators felt that the Viet Nam study protocol was in conflict with recommended international best practice, and the trial was stopped in October 2010. An amended study protocol in which ART was started at 2 weeks was developed and implemented. The ethics issues around this decision and the need to change the study protocol are discussed in this article.

Du fait de la nature et de la complexité des études cliniques, leur mise en œuvre est souvent longue après l'élaboration du protocole et son approbation éthique. Pendant cette période, il peut y avoir un changement des lignes directrices internationales de traitement et des recommandations qui provoquent un conflit entre le protocole et les meilleures pratiques recommandées internationalement. Nous décrivons ici la situation apparue dans une étude pharmacocinétique portant sur l'utilisation de deux doses différentes de rifabutin chez des patients atteints de tuberculose (TB) associée au virus de l'immunodéficience humaine et commençant un traitement antirétroviral (ART) à base de lopinavir-ritonavir en Afrique du Sud et au Viet Nam. Le protocole de l'étude spécifiait de commencer l'ART 10 semaines après le début de la thérapie antituberculeuse. En Afrique du Sud, l'étude a été approuvée en juin 2008, s'est déroulée comme prévu et a été achevée en juin 2010. Au Viet Nam, l'étude a été approuvée en octobre 2008 et a démarré en juin 2010. Quelques semaines après, l'Organisation Mondiale de la Santé a publié ses lignes directrices de 2010 pour l'utilisation de l'ART chez les adultes, dont l'une des vives recommandations (basée sur des données de qualité modérée) était de commencer l'ART entre 2 et 8 semaines après le début du traitement de la TB. L'arrivée de nouvelles preuves scientifiques est aussi venue à l'appui de cette recommandation. Les investigateurs ont eu le sentiment que le protocole d'étude au Viet Nam était en conflit avec les meilleures pratiques internationales et l'étude a été arrêtée en octobre 2010. Un protocole d'étude amendé a été développé et mis en œuvre. Les problèmes éthiques entourant cette décision et la nécessité de changer le protocole sont discutés dans ce papier.

Los ensayos clínicos, dadas sus características y su complejidad, suelen exigir mucho tiempo desde la elaboración del protocolo y la aprobación por parte del comité de ética hasta su realización. Durante este lapso, pueden surgir modificaciones en las recomendaciones y las directrices terapéuticas internacionales, lo cual genera un conflicto entre el protocolo del estudio y las prácticas óptimas recomendadas. A continuación se describe la situación que se presentó en Suráfrica y Viet Nam durante un estudio de farmacocinética sobre el uso de dos dosificaciones diferentes de rifabutina, en pacientes aquejados de tuberculosis (TB) asociada con la infección por el virus de la inmunodeficiencia humana (HIV), quienes habían comenzado el tratamiento antirretrovírico (ART) con un régimen basado en la asociación lopinavir y ritonavir. El protocolo del estudio precisaba que el ART se debía comenzar 10 semanas después de haber iniciado el tratamiento antituberculoso. En Suráfrica, el estudio recibió la aprobación en junio del 2008, comenzó en el tiempo previsto y se completó en agosto del 2010. En Viet Nam, se obtuvo la aprobación del estudio en octubre del 2008 y se comenzó en junio del 2010. A las pocas semanas, la Organización Mundial de Salud publicó sus directrices del ART en los adultos del 2010, una de cuyas recomendaciones más firmes consistía en que el ART se debía iniciar entre 2 y 8 semanas después de haber comenzado el tratamiento antituberculoso (con una calidad probatoria moderada). Algunos resultados científicos de aparición reciente respaldaban igualmente esta recomendación. Los investigadores consideraron que el protocolo del estudio en Viet Nam entraba en conflicto con las prácticas óptimas internacionales recomendadas e interrumpieron su realización en octubre del 2010. Se introdujeron modificaciones al protocolo, según las cuales el ART se comenzaría a las 2 semanas y se puso en práctica el estudio. En el presente artículo se analizan los aspectos éticos en torno a esta decisión y a la necesidad de modificar el protocolo del estudio.

Association of streptomycin resistance mutations with level of drug resistance and Mycobacterium tuberculosis genotypes.

OBJECTIVES: To determine 1) the relationship between specific streptomycin (SM) resistance mutations and the minimum inhibitory concentration (MIC), and 2) whether these mutations are preferentially associated with the Beijing genotype in Viet Nam. METHODS: A total of 131 consecutive Mycobacterium tuberculosis isolates resistant to either isoniazid (INH) or rifampicin (RMP), collected previously, were tested for SM resistance, spoligotyped and sequenced in the rpsL, rrs and gidB genes. The MIC for 50 mutants was also determined. RESULTS: Overall, 116/131 isolates were SM-resistant. The three most frequently occurring mutation sites in rpsL and rrs were at codon 43 of rpsL (72/116, 62.1%), rpsL88 (22/116, 18.9%) and rrs514 (8/116, 6.9%). Mutations in the rrs910 region were found in two isolates (1.7%), and three isolates had mutations in both rpsL and rrs (2.6%). gidB mutations were found in both resistant and susceptible strains. Among SM-resistant isolates resistant to INH/RMP, the Beijing genotype was strongly associated with rpsL43 mutation (aOR 23.6, 95%CI 2.9-193.4, P = 0.002). The median MIC for each mutation was as follows: rpsL43 = 256 µg/ml, rpsL88 = 16 µg/ml, 515 loop = 4 µg/ml, 910 region = 8 µg/ml, and double mutation = 256 µg/ml. We found a strong association between rpsL43 and high drug resistance levels, with all rpsL43 mutants having an MIC >256 µg/ml (P < 0.001).

Epiregulin (EREG) variation is associated with susceptibility to tuberculosis.

Although host genetics influences susceptibility to Mycobacterium tuberculosis, the human genes regulating pathogenesis remain largely unknown. We used M. tuberculosis-stimulated macrophage gene expression profiling in conjunction with a case-control genetic association study to discover epiregulin (EREG), as a novel candidate tuberculosis (TB) susceptibility gene. Using a genome-wide association study dataset, we found that among the 21 genes with greater than 50-fold induction, EREG had the most polymorphisms associated with TB. We genotyped haplotype-tagging polymorphisms in discovery (N = 337 cases, N = 380 controls) and validation (N = 332 cases) datasets and an EREG polymorphism (rs7675690) was associated with susceptibility to TB (genotypic comparison; corrected P = 0.00007). rs7675690 was also associated more strongly with infections caused by the Beijing lineage of M. tuberculosis when compared with non-Beijing strains (controls vs Beijing, OR 7.81, P = 8.7 × 10(-5); non-Beijing, OR 3.13, P = 0.074). Furthermore, EREG expression was induced in monocytes and peripheral blood mononuclear cells stimulated with M. tuberculosis as well as TLR4 and TLR2/1/6 ligands. In murine macrophages, EREG expression induced by M. tuberculosis was MYD88- and TLR2-dependent. Together, these data provide the first evidence for an important role for EREG as a susceptibility gene for human TB.

Improving the diagnosis of pulmonary tuberculosis in HIV-infected individuals in Ho Chi Minh City, Viet Nam.

SETTING: District 6, An Hoa Clinic in Ho Chi Minh City (HCMC), Viet Nam. OBJECTIVE: To evaluate the performance of various algorithms in tuberculosis (TB) screening and diagnosis in a human immunodeficiency virus (HIV) infected population in HCMC, Viet Nam. DESIGN: A cross-sectional study of 397 consecutive HIV-infected patients seeking care at the An Hoa Clinic from August 2009 to June 2010. Data on participant demographics, clinical status, chest radiography (CXR) and laboratory results were collected. A multiple logistic regression model was developed to assess the association of covariates and pulmonary TB (PTB). RESULTS: The prevalence of sputum culture-confirmed PTB, acid-fast bacilli (AFB) positive TB, and multidrugresistant TB among the 397 HIV-infected patients was respectively 7%, 2%, and 0.3%. Adjusted odds ratios for low CD4+ cell count, positive sputum smear, and CXR to positive sputum culture were respectively 3.17, 32.04 and 4.28. Clinical findings alone had poor sensitivity, but combining CD4+ cell count, AFB sputum smear and CXR had a more accurate diagnostic performance. CONCLUSION: Results suggest that symptom screening had poor clinical performance, and support the routine use of sputum culture to improve the detection of TB disease in HIV-infected individuals in Viet Nam. However, when routine sputum culture is not available, an algorithm combining CD4+ cell count, AFB sputum smear and CXR is recommended for diagnosing PTB.

Multiplex allele-specific polymerase chain reaction for detection of isoniazid resistance in Mycobacterium tuberculosis.

SETTING: Pham Ngoc Thach Tuberculosis Reference Hospital, Ho Chi Minh City, Viet Nam. DESIGN: A multiplex allele-specific polymerase chain reaction (MAS-PCR) was developed to detect mutations at the two most common sites responsible for isoniazid (INH) resistance in Mycobacterium tuberculosis: katG315 and inhA-15. The MAS-PCR is able to detect rare mutations at katG315, in addition to katG S315T. Conventional phenotypic proportion drug susceptibility testing on Löwenstein-Jensen media was used as a gold standard to compare the sensitivity and specificity of the commercial MTBDRplus line-probe assay and the MAS-PCR in 100 INH-resistant and 50 INH-susceptible isolates collected consecutively at Pham Ngoc Thach Hospital reference laboratory. RESULTS: The sensitivity and specificity on culture isolates were 90% (n = 90/100, 95%CI 0.83-0.94) and 100% (n = 50/50, 95%CI 0.93-1.0), respectively, for the MAS-PCR and the MTBDRplus assay. CONCLUSION: The MAS-PCR described here represents an alternative method for rapid screening for INH resistance in M. tuberculosis isolates.

Decrease in risk of tuberculosis infection despite increase in tuberculosis among young adults in urban Vietnam.

OBJECTIVE: To assess whether the increase in tuberculosis (TB) notification rates among young adults in Vietnam reflects increased transmission in the population at large. METHOD: Trends of case notification rates of new smear-positive TB were calculated from routinely reported data of district TB units over the period 1996-2005. Results from repeated tuberculin surveys among children aged 6-9 years were obtained to calculate the trend in annual risk of TB infection (ARTI). FINDINGS: From 1996 to 2006, notification rates in the age group 15-24 years increased by 4.3% per year, and more so in highly urbanised (6.7%) than in rural districts (1.7%). The ARTI in urban districts declined from 2.4% in 1992 to 1.2% in 1998 and 0.9% in 2005. In rural districts, the ARTI increased from 0.7% in 1991 to 1.2% in 1997, and then declined to 0.9% in 2006. CONCLUSION: The increase in TB notification rates among young adults in Ho Chi Minh Province is accompanied by a decrease in ARTI in children. This suggests that the trend in TB notification among young adults reflects increased rates of progression from infection to disease and/or increased transmission within this age group, rather than increased transmission in the population at large.

The Beijing genotype is associated with young age and multidrug-resistant tuberculosis in rural Vietnam.

BACKGROUND: Associations between multidrug resistance and the Mycobacterium tuberculosis Beijing genotype have been described mainly in populations with poor tuberculosis (TB) control such as prisons and inner cities, and may reflect shared risk factors rather than a biological association. OBJECTIVE: To study the association between genotype and drug resistance among TB patients in a population with adequate TB control. SETTING: Three rural districts in Vietnam. The study was performed at the Pham Ngoc Thach Tuberculosis and Lung Disease Hospital, Ho Chi Minh City, and the Tien Giang Provincial Tuberculosis and Lung Disease Hospital, My Tho, Vietnam. METHODS: Pretreatment sputum specimens were collected for culture, drug susceptibility testing and spoligotyping of all sputum smear-positive pulmonary TB patients consecutively diagnosed over a 3-year period. RESULTS: Beijing genotype infections were observed in 614 of 1744 (35%) patients. Beijing strains were more common among female (adjusted odds ratio [aOR] 1.4, P = 0.005), young (aOR 2.8, P < 0.001) and previously treated patients (aOR 2.4, P < 0.001). The Beijing genotype was associated with any resistance (aOR 3.7, P < 0.001) and multidrug resistance (aOR 6.8, P < 0.001) among new patients, and with any resistance (aOR 2.7, P = 0.005) but not with multidrug resistance (aOR 1.4, P = 0.545) among previously treated patients. CONCLUSION: In Vietnam, Beijing genotype is associated with young age and in new patients with multidrug resistance despite adequate TB control, suggesting a biological association. This potentially undermines the effectiveness of TB control in countries where Beijing genotype infections are common.

Validation of the line-probe assay for rapid detection of rifampicin-resistant Mycobacterium tuberculosis in Vietnam.

BACKGROUND: Delays in identifying multidrug-resistant tuberculosis (MDR-TB) contribute to higher TB morbidity and mortality, and ongoing transmission. The line-probe assay (LiPA) is a rapid, commercially available polymerase chain reaction based assay that detects most mutations in the rpoB gene for rifampicin (RMP) resistance. We validated and compared this assay with conventional drug susceptibility testing (DST). METHODS: We re-cultured a random sample of stored isolates known to be either RMP-resistant or RMP-susceptible according to DST (proportion method). We performed a blinded comparison between LiPA and conventional DST. Genetic sequencing of the rpoB gene was performed on RMP-resistant isolates and discordant results. RESULTS: We tested 79 RMP-resistant and 64 RMP-susceptible strains. Concordance of LiPA with DST was 94%. For detecting RMP resistance, LiPA sensitivity was 90% and specificity was 100%. Molecular analysis of possible false-negative isolates by LiPA revealed an absence of mutations in the rpoB gene. RMP resistance was a good proxy for MDR-TB, as 66 (93%) of 71 RMP-resistant isolates were also isoniazid-resistant. CONCLUSION: The LiPA provided rapid results that were highly predictive of RMP resistance and MDR-TB. False-negatives occurred, but only among isolates with mutations in regions not assessed by LiPA. Performance and cost-effectiveness should be evaluated in patients during routine program conditions.

Comparison of MAS-PCR and GenoType MTBDR assay for the detection of rifampicin-resistant Mycobacterium tuberculosis.

SETTING: Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases, the tertiary referral hospital for tuberculosis (TB) in Southern Vietnam. OBJECTIVE: To develop and evaluate a simple, rapid and accurate multiplex allele specific polymerase chain reaction (MAS-PCR) test to detect rifampicin (RMP) resistance point mutations at codons 516, 526 or 531 in the rpoB gene of Mycobacterium tuberculosis. DESIGN: The novel MAS-PCR was compared with the commercial M. tuberculosis Drug Resistance (MTBDR) test in 104 RMP-resistant and 50 RMP-susceptible routine isolates, defined by conventional 1% phenotypic susceptibility testing. RESULTS: The sensitivity of the MAS-PCR and MTBDR tests was respectively 83.7% (95%CI 75.1-90.2) and 93.3% (95%CI 86.6-97.3). Both tests were 100% specific. The negative predictive value was 74.6% (95%CI 65.3-83.1) for the MAS-PCR and 87.7% (95%CI 80.0-93.6) for the MTBDR test. CONCLUSION: The MTBDR test, although more sensitive, is currently prohibitively expensive in resource-poor, high-burden settings. The MAS-PCR described here presents a less laborious economic alternative. A susceptible result returned by either test cannot be used to exclude multidrug-resistant TB.

Fluoroquinolone resistance detection in Mycobacterium tuberculosis with locked nucleic acid probe real-time PCR.

SETTING: Pham Ngoc Thach Hospital for Tuberculosis and Lung Diseases, Ho Chi Minh City, Vietnam. OBJECTIVE: Fluoroquinolones (FQs) are increasingly used in the treatment of tuberculosis (TB) and are the second-line drugs of choice for treatment of multidrug-resistant TB. We aimed to set up a polymerase chain reaction (PCR) based assay to detect the most common FQ-resistance-associated mutations in gyrase A (gyrA) of Mycobacterium tuberculosis. DESIGN: A total of 42 FQ-resistant and 40 FQ-susceptible isolates were collected in 2005-2006 and sequenced in gyrA. Using sequencing results as gold standard, a real-time PCR using three locked nucleic acid probes (LNA-PCR) was designed to detect mutations at positions 90, 91 and 94 (97% of gyrA FQ-resistance-associated mutations) and evaluated. RESULTS: Sequencing of 42 FQ-resistant isolates revealed no gyrA mutations in 10 isolates, 20 isolates had a single mutation and 12 isolates showed double peaks at resistance-associated alleles, suggesting a heterogeneous population. With LNA-PCR, all wild-type and 19/20 mutant isolates were correctly identified. Eleven of 12 heterogeneous isolates were correctly identified as resistant mutants. Overall, 71% ([19 + 11]/42) of phenotypically FQ-resistant isolates were detected. Specificity was 100% on 40 FQ-susceptible isolates. CONCLUSION: This assay provides a simple and rapid means to reliably detect FQ-resistance-associated gyrA mutations in M. tuberculosis.

A polymorphism in human TLR2 is associated with increased susceptibility to tuberculous meningitis.

Tuberculous meningitis (TBM) results from the haematogenous dissemination of Mycobacterium tuberculosis from the lung to the brain. Dissemination is believed to occur early during infection, before the development of adaptive immunity. Toll-like receptor 2 (TLR2) mediates recognition of M. tuberculosis and initiates the innate immune response to infection. We hypothesized that polymorphisms in the TLR2 gene influence bacterial dissemination and the development of TBM. A case-control study was designed to test the hypothesis. Cases of bacteriologically confirmed pulmonary tuberculosis (TB) (n=183) and TBM (n=175), and cord blood controls (n=389) were enrolled in Vietnam. TLR2 genotype 597CC was associated with susceptibility to TB (odds ratio (OR)=2.22, 95% confidence interval (CI): 1.23-3.99). The association was found with meningeal rather than pulmonary TB (TBM vs control, OR=3.26, 95% CI: 1.72-6.18), and was strongest when miliary TB was found on chest radiography (controls vs TBM with miliary TB, OR=5.28, 95% CI: 2.20-12.65). Furthermore, the association increased with the severity of neurologic symptoms (grade I TBM, OR=1.93, 95% CI: 0.54-6.92; grade II, OR=3.32, 95% CI: 0.84-13.2; and grade III, OR=5.70, 95% CI: 1.81-18.0). These results demonstrate a strong association of TLR2 SNP T597C with the development of TBM and miliary TB and indicate that TLR2 influences the dissemination of M. tuberculosis.

Drug resistance among smear-positive tuberculosis patients in Ho Chi Minh City, Vietnam.

OBJECTIVES: To assess the pattern of drug resistance among smear-positive tuberculosis (TB) patients in an inner city area in Vietnam. METHODS: A random sample of patients diagnosed by the national TB programme (NTP) were offered HIV testing and submitted sputum for Mycobacterium tuberculosis drug sensitivity testing. RESULTS: Of 1433 isolates from new patients, 360 (25%) were resistant to isoniazid (INH), 57 (4.0%) to rifampicin (RMP), 421 (29%) to streptomycin (SM) and 28 (2.0%) to ethambutol. Among 401 previously treated patients, this was 218 (54%), 109 (27%), 217 (54%) and 26 (7%), respectively. Multidrug resistance (MDR) was observed in 55 (3.8%) new and 102 (25%) previously treated patients. RMP resistance was strongly associated with resistance to INH (OR 46) and INH plus SM (OR 91, P = 0.004). Prevalence of drug resistance tended to decrease with age. Neither any resistance nor MDR was significantly associated with HIV infection. CONCLUSIONS: In this inner city area, levels of drug resistance, in particular of MDR among previously treated patients, are high. This may be related to the use of NTP regimens in the context of highly prevalent combined SM and INH resistance which may favour acquisition of RMP resistance.

Treatment outcomes by drug resistance and HIV status among tuberculosis patients in Ho Chi Minh City, Vietnam.

OBJECTIVE: To assess the combined effects of drug resistance, HIV infection and treatment regimen on treatment outcomes of smear-positive tuberculosis patients in Ho Chi Minh City, Vietnam. METHODS: A representative sample of patients diagnosed in 1998-2000 in 12 urban districts was offered HIV testing and submitted sputum for Mycobacterium tuberculosis culture and drug susceptibility testing. New patients were treated with 2SHRZ/6HE in nine districts and with 2SHRZ/4RH in three districts. RESULTS: The cure rate was 87% (1240/1430) among new patients compared to only 73% (287/391) among previously treated patients. Failure was associated with multidrug resistance (adjusted odds ratios [aOR] 49.6 and 16.6, respectively) and combined resistance to isoniazid (INH) and streptomycin (SM) (aOR 13.4 and 4.8), but not with HIV infection. New patients had an increased risk of failure on treatment with 2SHRZ/4RH compared to 2SHRZ/6HE if the isolate was resistant to INH and SM (aOR 2.8, P = 0.016). Death during treatment occurred in 15 of 50 HIV-infected patients (30%). Mortality was significantly associated with HIV infection (aOR 29.9), multidrug resistance (aOR 4.7) and other resistance to two or more drugs (aOR 2.1). CONCLUSION: In Vietnam, adaptation of treatment regimens should be considered, and interventions are needed to reduce the high mortality among HIV-infected patients.

Improved sensitivity of sputum smear microscopy after processing specimens with C18-carboxypropylbetaine to detect acid-fast bacilli: a study of United States-bound immigrants from Vietnam.

The goal of this study was to evaluate the effect of the specimen-processing method that uses the detergent C18-carboxypropylbetaine (CB-18) on the sensitivity of acid-fast bacillus (AFB) staining. Vietnamese immigrants with abnormal chest radiographs provided up to three sputum specimens, which were examined for acid-fast bacilli by use of direct auramine and Ziehl-Neelsen staining. The remaining sputum was split; half was cultured, and the other half was incubated with CB-18 for 24 h, centrifuged, and examined for AFB by both staining methods. CB-18 processing improved the sensitivity of AFB staining by 20 to 30% (only differences in auramine sensitivity were statistically significant) but reduced specificity by approximately 20% (P < 0.05). These findings have direct utility for overseas migrant tuberculosis screening programs, for which maximizing test sensitivity is a major objective.

Treatment results among tuberculosis patients treated by private lung specialists involved in a public-private mix project in Vietnam.

SETTING: Ho Chi Minh City, Vietnam. OBJECTIVES: To determine treatment outcome among patients treated by private lung specialists in a public-private mix (PPM) project for improved TB control. METHODS: Cohorts of patients treated by private lung specialists within the PPM project and in National Tuberculosis Programme (NTP) facilities were followed for up to 12 months. The quality of case management and treatment outcome was determined based on information in treatment cards. As a complement, questionnaire surveys of private providers (PPs) and patients and focus group discussions with PPs were conducted. RESULTS: Among 400 patients treated by PPs, 36 different treatment regimens were used. Directly observed treatment was not used at all, and treatment evaluation with sputum smear microscopy and health education was inadequate. Overall treatment success was 60% and the default rate was 37%, which was considerably worse than in NTP facilities. CONCLUSION: This PPM project, which used a combination of training, supervision, standardised referral and information system and financial incentives, did not achieve sufficiently good treatment outcome by PPs. Possible reasons for the poor outcome include absence of subsidisation of drug costs and lack of regulatory enforcement.

Referring TB suspects from private pharmacies to the National Tuberculosis Programme: experiences from two districts in Ho Chi Minh City, Vietnam.

SETTING: Ho Chi Minh City, Vietnam. OBJECTIVE: To describe pharmacists' attitudes towards referring TB suspects to the National Tuberculosis Programme (NTP) and to evaluate the feasibility of a new referral system. METHODS: 1) Questionnaire survey of 150 private pharmacies; 2) qualitative interviews with 16 pharmacists; 3) monitoring the use of new referral forms for 21 months. RESULTS: Use of a simple referral form was thought to be manageable by 72% of the pharmacists. Pharmacists identified a number of different types of risks associated with referral of TB suspects to the NTP; clients could turn to another pharmacy (61% of respondents); criticise the pharmacist if it appears that they do not have TB (42%); or remain untreated because they are not able to visit the NTP (41%). Fifty-eight (39%) of eligible pharmacies referred at least one client. At least 373 suspects were referred, 149 were tested and 10 had TB. CONCLUSIONS: It is feasible to let pharmacies refer TB suspects. For there to be a significant impact on case detection, it is important to acknowledge a number of concerns expressed by pharmacists and attempt to change both clients' and providers' expectations with regard to the pharmacists' role.

Drug resistance among failure and relapse cases of tuberculosis: is the standard re-treatment regimen adequate?

OBJECTIVE: To determine acquired drug resistance among failure and relapse cases after treatment of new smear-positive tuberculosis. METHODS: A cohort of 2901 patients with new smear-positive tuberculosis was enrolled in Vietnam. Sputum samples were stored at enrolment. Upon failure or relapse, another sputum sample was collected. Both were cultured and underwent drug susceptibility testing and restriction fragment length polymorphism (RFLP) typing. RESULTS: Of 40 failure cases, 17 had multidrug resistance (MDR) at enrolment. At failure, 15 of the 23 (65%) patients without primary MDR had acquired MDR. Of 39 relapse cases and 143 controls, none had primary MDR. CONCLUSION: Primary drug resistance was a strong risk factor for failure and relapse and for acquiring further resistance. As 80% of failure cases had MDR, the standard re-treatment regimen appears inadequate for failure cases in this control programme with a very high cure rate among new cases.

Public-private mix for improved TB control in Ho Chi Minh City, Vietnam: an assessment of its impact on case detection.

SETTING: Ho Chi Minh City (HCMC), Vietnam. OBJECTIVE: To assess the impact on case detection of a public-private mix (PPM) project linking private providers (PPs) to the National Tuberculosis Programme (NTP). METHOD: Nine-month monitoring of referral and diagnostic data recorded in new referral forms and treatment cards for PPs and upgraded NTP registers. RESULTS: A total of 1549 TB suspects were referred, of whom 1090 (70%) actually went to the NTP for sputum examination. A total of 569 cases were detected through referrals or notification, of whom 45% were new sputum smear-positive cases. The case detection of new sputum smear-positive cases in PPM districts increased by 18% (21/100,000, 95%CI 0-42) compared to the previous year, while a slight decrease occurred in control districts. In HCMC as a whole, case detection increased by 7% (7/100,000, 95%CI 2-11/100,000). Among sputum smear-positive cases detected in NTP through referrals from PPs, 58% defaulted before initiating treatment. CONCLUSIONS: The tendency towards increased case detection associated with this PPM indicates a potential for utilising PPs to improve case detection. However, the NTP and PPs should jointly address the problem of initial default before considering expansion of this PPM model.