Limited Nosocomial Transmission of Drug-Resistant Tuberculosis, Moldova

Applying whole-genome-sequencing, we aimed to detect transmission events of multidrug-resistant/rifampin-resistant strains of Mycobacterium tuberculosis complex at a tuberculosis hospital in Chisinau, Moldova. We recorded ward, room, and bed information for each patient and monitored in-hospital transfers over 1 year. Detailed molecular and patient surveillance revealed only 2 nosocomial transmission events.

Decentralized, Integrated Treatment of RR/MDR-TB and HIV Using a Bedaquiline-Based, Short-Course Regimen Is Effective and Associated With Improved HIV Disease Control

BACKGROUND

In decentralized sites, with fewer resources and a high prevalence of advanced HIV, the effectiveness of the new short-course, bedaquiline-based regimen for rifampicin-resistant and multidrug-resistant tuberculosis (RR/MDR-TB) is not well-described.

SETTING

Adults with pulmonary RR/MDR-TB initiating the short-course regimen in KwaZulu-Natal, South Africa were prospectively enrolled at a decentralized program that integrated person-centered TB care.

METHODS

In addition to standard of care monitoring, study visits occurred at enrollment and months 1, 2, 4, 6, and 9. Favorable RR/MDR-TB outcome was defined as cure or treatment completion without loss to follow-up, death, or failure by treatment. In patients with HIV, we assessed antiretroviral therapy (ART) uptake, virologic and immunologic outcomes.

RESULTS

Among 57 patients, HIV was present in 73.7% (95% CI: 60.3-84.5), with a median CD4 count of 170 cells/mm 3 (intraquartile range 49-314). A favorable RR/MDR-TB outcome was achieved in 78.9% (CI: 67.1-87.9). Three deaths occurred, all in the setting of baseline advanced HIV and elevated viral load. Overall, 21.1% (95% CI: 12.1-32.9) experienced a severe or life-threatening adverse event, the most common of which was anemia. Among patients with HIV, enrollment resulted in increased ART uptake by 24% (95% CI: 12.1%-39.4%), a significant improvement from baseline ( P = 0.004); virologic suppression during concomitant treatment was observed in 71.4% (n = 30, 95% CI: 55.4-84.3).

CONCLUSION

Decentralized, person-centered care for RR/MDR-TB in patients with HIV using the short-course, bedaquiline-based regimen is effective and safe. In patients with HIV, enrollment led to improved ART use and reassuring virologic outcomes.

Concordance of three approaches for operationalizing outcome definitions for multidrug-resistant TB

BACKGROUND: The WHO provides standardized outcome definitions for rifampicin-resistant (RR) and multidrug-resistant (MDR) TB. However, operationalizing these definitions can be challenging in some clinical settings, and incorrect classification may generate bias in reporting and research. Outcomes calculated by algorithms can increase standardization and be adapted to suit the research question. We evaluated concordance between clinician-assigned treatment outcomes and outcomes calculated based on one of two standardized algorithms, one which identified failure at its earliest possible recurrence (i.e., failure-dominant algorithm), and one which calculated the outcome based on culture results at the end of treatment, regardless of early occurrence of failure (i.e., success-dominant algorithm).METHODS: Among 2,525 patients enrolled in the multi-country endTB observational study, we calculated the frequencies of concordance using cross-tabulations of clinician-assigned and algorithm-assigned outcomes. We summarized the common discrepancies.RESULTS: Treatment success calculated by algorithms had high concordance with treatment success assigned by clinicians (95.8 and 97.7% for failure-dominant and success-dominant algorithms, respectively). The frequency and pattern of the most common discrepancies varied by country.CONCLUSION: High concordance was found between clinician-assigned and algorithm-assigned outcomes. Heterogeneity in discrepancies across settings suggests that using algorithms to calculate outcomes may minimize bias.

How to Effectively Identify Patients With Rifampin-Resistant Tuberculosis in China: Perspectives of Stakeholders Among Service Providers

To evaluate China's current rifampin-resistant tuberculosis (RR-TB) screening strategy from stakeholders' perspectives, the perceptions, attitudes, and interests of 245 stakeholders from three eastern, central, and western China provinces on RR-TB screening strategies, were investigated through stakeholder survey and interview. The attitudes toward three RR-TB screening strategies were statistically different: inclination to choose who to screen (Z = 98.477; P < 0.001), funding for rapid diagnostic technology screening either by reimbursed health insurance or directly subsidized financial assistance (Z = 4.142, P < 0.001), and respondents' attitude during RR-TB screening implementation levels (Z = 2.380, P = 0.017). In conclusion, RR-TB screening scope could be expanded by applying rapid diagnostic technologies. Provinces with different economic status could adjust their screening policies accordingly.

Added Value of Comprehensive Program to Provide Universal Access to Care for Sputum Smear-Negative Drug-Resistant Tuberculosis, China

The increase in drug-resistant tuberculosis in China calls for scaling up rapid diagnosis. We evaluated introduction of rapid resistance testing by line-probe assay for all patients with a diagnosis of pulmonary tuberculosis in 2 prefectures in middle and eastern China. We analyzed sputum samples for smear-positive patients and cultures for smear-negative patients. We used a before–after comparison of baseline and intervention periods (12 months each) and analyzed data for 5,222 baseline period patients and 4,364 intervention period patients. The number of patients with rifampin resistance increased from 30 in the baseline period to 97 in the intervention period for smear-positive patients and from 0 to 13 for smear-negative patients, reflecting a low proportion of positive cultures (410/2,844, 14.4%). Expanding rapid testing for drug resistance for smear-positive patients resulted in a 3-fold increase in patients with diagnoses of rifampin-resistant tuberculosis. However, testing smear-negative patients had limited added value because of a low culture-positive rate.

How Well Do Routine Molecular Diagnostics Detect Rifampin Heteroresistance in Mycobacterium tuberculosis?

Rifampin heteroresistance—where rifampin-resistant and -susceptible tuberculosis (TB) bacilli coexist—may result in failed standard TB treatment and potential spread of rifampin-resistant strains. The detection of rifampin heteroresistance in routine rapid diagnostic tests (RDTs) allows for patients to receive prompt and effective multidrug-resistant-TB treatment and may improve rifampin-resistant TB control.

Rifampin heteroresistance—where rifampin-resistant and -susceptible tuberculosis (TB) bacilli coexist—may result in failed standard TB treatment and potential spread of rifampin-resistant strains. The detection of rifampin heteroresistance in routine rapid diagnostic tests (RDTs) allows for patients to receive prompt and effective multidrug-resistant-TB treatment and may improve rifampin-resistant TB control. The limit of detection (LOD) of rifampin heteroresistance for phenotypic drug susceptibility testing by the proportion method is 1% and, yet, is insufficiently documented for RDTs. We, therefore, aimed to determine, for the four RDTs (XpertMTB/RIF, XpertMTB/RIF Ultra, GenoTypeMTBDRplusv2.0, and GenoscholarNTM+MDRTBII), the LOD per probe and mutation, validated by CFU counting and targeted deep sequencing (Deeplex-MycTB). We selected one rifampin-susceptible and four rifampin-resistant strains, with mutations D435V, H445D, H445Y, and S450L, respectively, mixed them in various proportions in triplicate, tested them with each RDT, and determined the LODs per mutation type. Deeplex-MycTB revealed concordant proportions of the minority resistant variants in the mixtures. The Deeplex-MycTB-validated LODs ranged from 20% to 80% for XpertMTB/RIF, 20% to 70% for Xpert Ultra, 5% to 10% for GenoTypeMTBDRplusv2.0, and 1% to 10% for GenoscholarNTM+MDRTBII for the different mutations. Deeplex-MycTB, GenoTypeMTBDRplusv2.0, and GenoscholarNTM+MDRTBII provide explicit information on rifampin heteroresistance for the most frequently detected mutations. Classic Xpert and Ultra report rifampin heteroresistance as rifampin resistance, while Ultra may denote rifampin heteroresistance through “mixed patterns” of wild-type and mutant melt probe, melt peak temperatures. Overall, our findings inform end users that the threshold for reporting resistance in the case of rifampin heteroresistance is the highest for Classic Xpert and Ultra to resolve phenotypic and genotypic discordant rifampin-resistant TB results.

Use of drug-susceptibility testing for management of drug-resistant tuberculosis, Thailand, 2004-2008

In 2004, routine use of culture and drug-susceptibility testing (DST) was implemented for persons in 5 Thailand provinces with a diagnosis of tuberculosis (TB). To determine if DST results were being used to guide treatment, we conducted a retrospective chart review for patients with rifampin-resistant or multidrug-resistant (MDR) TB during 2004–2008. A total of 208 patients were identified. Median time from clinical sample collection to physician review of DST results was 114 days. Only 5.8% of patients with MDR TB were empirically prescribed an appropriate regimen; an additional 31.3% received an appropriate regimen after DST results were reviewed. Most patients with rifampin -resistant or MDR TB had successful treatment outcomes. Patients with HIV co-infection and patients who were unmarried or had received category II treatment before DST results were reviewed had less successful outcomes. Overall, review of available DST results was delayed, and results were rarely used to improve treatment.