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Background: Berotralstat (BCX7353) is an oral, once-daily inhibitor of plasma kallikrein recently approved for prevention of angioedema attacks in adults and adolescents with hereditary angioedema (HAE). The objective of this report is to summarize results from an interim analysis of an ongoing long-term safety study of berotralstat in patients with HAE. Methods: APeX-S is an ongoing, phase 2, open-label study conducted in 22 countries (ClinicalTrials.gov, NCT03472040). Eligible patients with a clinical diagnosis of HAE due to C1 inhibitor deficiency (HAE-C1-INH) were centrally allocated to receive berotralstat 150 or 110 mg once daily. The primary objective was to determine long-term safety and the secondary objective was to evaluate effectiveness. Results: Enrolled patients (N = 227) received berotralstat 150 mg (n = 127) or 110 mg (n = 100) once daily. The median (range) duration of exposure was 342 (11–540) and 307 (14–429) days for the 150-mg and 110-mg groups, respectively. Treatment-emergent adverse events (TEAEs) occurred in 91% (n = 206) of patients. The most common TEAEs across treatment groups were upper respiratory tract infection (n = 91, 40%), abdominal pain (n = 57, 25%), headache (n = 40, 18%), and diarrhea (n = 31, 14%) and were mostly mild to moderate. Fifty percent (n = 113) of patients had at least one drug-related adverse event (AE; 150 mg, n = 57 [45%]; 110 mg, n = 56 [56%]), and discontinuations due to AEs occurred in 19 (8%) patients (150 mg, n = 13 [10%]; 110 mg, n = 6 [6%]). Three (1.3%) patients experienced a drug-related serious TEAE. Among patients who received berotralstat through 48 weeks (150 mg, n = 73; 110 mg, n = 30), median HAE attack rates were low in month 1 (150 mg, 1.0 attacks/month; 110 mg, 0.5 attacks/month) and remained low through 12 months (0 attacks/month in both dose groups). Mean HAE attack rates followed a similar trend, and no evidence for patient tolerance to berotralstat emerged. In both dose groups, angioedema quality of life scores showed clinically meaningful changes from baseline. Conclusions: In this analysis, both berotralstat doses, 150 and 110 mg once daily, were generally well tolerated. Effectiveness results support the durability and robustness of berotralstat as prophylactic therapy in patients with HAE. Trial registration: The study is registered with ClinicalTrials.gov (NCT03472040).

PURPOSE OF REVIEW: Immune-mediated adverse drug reactions (IM-ADRs) are many times more common in HIV-infected patients. Usual offending drugs include antiretroviral and antiinfectives, but the burden of specific drug IM-ADRs is population-specific; changing as new and fixed dose combinations enter the market, and drug-resistance patterns demand. This review considers recent literature on epidemiology, mechanisms, clinical management and prevention of IM-ADRs amongst persons living with HIV/AIDS. RECENT FINDINGS: Epidemiological studies continue to describe high rates of delayed hypersensitivity to known offenders, as well as similar reactions in preexposure prophylaxis. IM-ADRs to oral and injectable integrase strand transfer inhibitors are reported with expanding use. The clinical spectrum and management of IM-ADRs occurring in HIV-infected populations is similar to uninfected; with exceptions such as a recently described severe delayed efavirenz DILI with high mortality. Furthermore, the context can be unique, such as the lower than expected mortality in a Stevens–Johnson syndrome and toxic epidermal necrolysis (SJS/TEN) cohort from a HIV/TB high burden setting. Programmatic data showing the near complete elimination of Abacavir drug hypersensitivity syndrome following implementation of HLA-B57:01 screening is a stellar example of how prevention is possible with mechanistic insight. SUMMARY: IM-ADRs remain a challenge in persons living with HIV. The complexities posed by polypharmacy, overlapping drug toxicities, drug interactions, overlap of IM-ADRs with other diseases, limited alternative drugs, and vulnerable patients with advanced immunosuppression with high mortality, necessitate increased use of drug provocation testing, treat-through and desensitization strategies. There is an urgent need for improved diagnostics and predictive biomarkers for prevention, or to guide treat-through, rechallenge and desensitization approaches.

BACKGROUND: Based on current WHO guidelines, hospitalized tuberculosis (TB) and HIV co-infected patients with CD4 count

Background Patients with previous tuberculosis may have residual DNA in sputum that confounds nucleic acid amplification tests such as Xpert MTB/RIF. Little is known about the frequency of Xpert-positive, culture-negative ("false positive") results in retreatment patients, whether these are distinguishable from true positives, and whether Xpert's automated filter-based wash step reduces false positivity by removing residual DNA associated with nonintact cells. Methods Pretreatment patients (n = 2889) with symptoms of tuberculosis from Cape Town, South Africa, underwent a sputum-based liquid culture and Xpert. We also compared Xpert results from dilutions of intact or heat-lysed and mechanically lysed bacilli. Results Retreatment cases were more likely to be Xpert false-positive (45/321 Xpert-positive retreatment cases were false-positive) than new cases (40/461) (14% [95% confidence interval {CI}, 10%-18%] vs 8% [95% CI, 6%-12%];P= .018). Fewer years since treatment completion (adjusted odds ratio [aOR], 0.85 [95% CI, .73-.99]), less mycobacterial DNA (aOR, 1.14 [95% CI, 1.03-1.27] per cycle threshold [CT]), and a chest radiograph not suggestive of active tuberculosis (aOR, 0.22 [95% CI, .06-.82]) were associated with false positivity. CThad suboptimal accuracy for false positivity: 46% of Xpert-positives with CT> 30 would be false positive, although 70% of false positives would be missed. CT's predictive ability (area under the curve, 0.83 [95% CI, .76-.90]) was not improved by additional variables. Xpert detected nonviable, nonintact bacilli without a change in CTvs controls. Conclusions One in 7 Xpert-positive retreatment patients were culture negative and potentially false positive. False positivity was associated with recent previous tuberculosis, high CT, and a chest radiograph not suggestive of active tuberculosis. Clinicians may consider awaiting confirmatory testing in retreatment patients with CT> 30; however, most false positives fall below this cut-point. Xpert can detect DNA from nonviable, nonintact bacilli.

Background Urine LAM testing has been approved by the WHO for use in hospitalised patients with advanced immunosuppression. However, sensitivity remains suboptimal. We therefore examined the incremental diagnostic sensitivity of early morning urine (EMU) versus random urine sampling using the Determine® lateral flow lipoarabinomannan assay (LF-LAM) in HIV-TB co-infected patients. Methods Consenting HIV-infected inpatients, screened as part of a larger prospective randomized controlled trial, that were treated for TB, and could donate matched random and EMU samples were included. Thus paired sample were collected from the same patient, LF-LAM was graded using the pre-January 2014, with grade 1 and 2 manufacturer-designated cut-points (the latter designated grade 1 after January 2014). Single sputum Xpert-MTB/RIF and/or TB culture positivity served as the reference standard (definite TB). Those treated for TB but not meeting this standard were designated probable TB. Results 123 HIV-infected patients commenced anti-TB treatment and provided matched random and EMU samples. 33% (41/123) and 67% (82/123) had definite and probable TB, respectively. Amongst those with definite TB LF-LAM sensitivity (95%CI), using the grade 2 cut-point, increased from 12% (5–24; 5/43) to 39% (26–54; 16/41) with random versus EMU, respectively (p = 0.005). Similarly, amongst probable TB, LF-LAM sensitivity increased from 10% (5–17; 8/83) to 24% (16–34; 20/82) (p = 0.001). LF-LAM specificity was not determined. Conclusion This proof of concept study indicates that EMU could improve the sensitivity of LF-LAM in hospitalised TB-HIV co-infected patients. These data have implications for clinical practice. Electronic supplementary material The online version of this article (doi:10.1186/s12879-017-2313-0) contains supplementary material, which is available to authorized users.

Summary Background The Xpert MTB/RIF test for tuberculosis is being rolled out in many countries, but evidence is lacking regarding its implementation outside laboratories, ability to inform same-day treatment decisions at the point of care, and clinical effect on tuberculosis-related morbidity. We aimed to assess the feasibility, accuracy, and clinical effect of point-of-care Xpert MTB/RIF testing at primary-care health-care facilities in southern Africa. Methods In this pragmatic, randomised, parallel-group, multicentre trial, we recruited adults with symptoms suggestive of active tuberculosis from five primary-care health-care facilities in South Africa, Zimbabwe, Zambia, and Tanzania. Eligible patients were randomly assigned using pregenerated tables to nurse-performed Xpert MTB/RIF at the clinic or sputum smear microscopy. Participants with a negative test result were empirically managed according to local WHO-compliant guidelines. Our primary outcome was tuberculosis-related morbidity (measured with the TBscore and Karnofsky performance score [KPS]) in culture-positive patients who had begun anti-tuberculosis treatment, measured at 2 months and 6 months after randomisation, analysed by intention to treat. This trial is registered with Clinicaltrials.gov, number NCT01554384. Findings Between April 12, 2011, and March 30, 2012, we randomly assigned 758 patients to smear microscopy (182 culture positive) and 744 to Xpert MTB/RIF (185 culture positive). Median TBscore in culture-positive patients did not differ between groups at 2 months (2 [IQR 0–3] in the smear microscopy group vs 2 [0·25–3] in the MTB/RIF group; p=0·85) or 6 months (1 [0–3] vs 1 [0–3]; p=0·35), nor did median KPS at 2 months (80 [70–90] vs 90 [80–90]; p=0·23) or 6 months (100 [90–100] vs 100 [90–100]; p=0·85). Point-of-care MTB/RIF had higher sensitivity than microscopy (154 [83%] of 185 vs 91 [50%] of 182; p=0·0001) but similar specificity (517 [95%] 544 vs 540 [96%] of 560; p=0·25), and had similar sensitivity to laboratory-based MTB/RIF (292 [83%] of 351; p=0·99) but higher specificity (952 [92%] of 1037; p=0·0173). 34 (5%) of 744 tests with point-of-care MTB/RIF and 82 (6%) of 1411 with laboratory-based MTB/RIF failed (p=0·22). Compared with the microscopy group, more patients in the MTB/RIF group had a same-day diagnosis (178 [24%] of 744 vs 99 [13%] of 758; p vs 115 [15%] of 758; p=0·0002). Although, by end of the study, more culture-positive patients in the MTB/RIF group were on treatment due to reduced dropout (15 [8%] of 185 in the MTB/RIF group did not receive treatment vs 28 [15%] of 182 in the microscopy group; p=0·0302), the proportions of all patients on treatment in each group by day 56 were similar (320 [43%] of 744 in the MTB/RIF group vs 317 [42%] of 758 in the microscopy group; p=0·6408). Interpretation Xpert MTB/RIF can be accurately administered by a nurse in primary-care clinics, resulting in more patients starting same-day treatment, more culture-positive patients starting therapy, and a shorter time to treatment. However, the benefits did not translate into lower tuberculosis-related morbidity, partly because of high levels of empirical-evidence-based treatment in smear-negative patients. Funding European and Developing Countries Clinical Trials Partnership, National Research Foundation, and Claude Leon Foundation.

Background Genotype® MTBDRsl (MTBDRsl) is a rapid DNA-based test for detecting specific mutations associated with resistance to fluoroquinolones and second-line injectable drugs (SLIDs) in Mycobacterium tuberculosis complex. MTBDRsl version 2.0 (released in 2015) identifies the mutations detected by version 1.0, as well as additional mutations. The test may be performed on a culture isolate or a patient specimen, which eliminates delays associated with culture. Version 1.0 requires a smear-positive specimen, while version 2.0 may use a smear-positive or -negative specimen. We performed this updated review as part of a World Health Organization process to develop updated guidelines for using MTBDRsl. Objectives To assess and compare the diagnostic accuracy of MTBDRsl for: 1. fluoroquinolone resistance, 2. SLID resistance, and 3. extensively drug-resistant tuberculosis, indirectly on a M. tuberculosis isolate grown from culture or directly on a patient specimen. Participants were people with rifampicin-resistant or multidrug-resistant tuberculosis. The role of MTBDRsl would be as the initial test, replacing culture-based drug susceptibility testing (DST), for detecting second-line drug resistance. Search methods We searched the following databases without language restrictions up to 21 September 2015: the Cochrane Infectious Diseases Group Specialized Register; MEDLINE; Embase OVID; Science Citation Index Expanded, Conference Proceedings Citation Index-Science, and BIOSIS Previews (all three from Web of Science); LILACS; and SCOPUS; registers for ongoing trials; and ProQuest Dissertations & Theses A&I. We reviewed references from included studies and contacted specialists in the field. Selection criteria We included cross-sectional and case-control studies that determined MTBDRsl accuracy against a defined reference standard (culture-based DST, genetic sequencing, or both). Data collection and analysis Two review authors independently extracted data and assessed quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We synthesized data for versions 1.0 and 2.0 separately. We estimated MTBDRsl sensitivity and specificity for fluoroquinolone resistance, SLID resistance, and extensively drug-resistant tuberculosis when the test was performed indirectly or directly (smear-positive specimen for version 1.0, smear-positive or -negative specimen for version 2.0). We explored the influence on accuracy estimates of individual drugs within a drug class and of different reference standards. We performed most analyses using a bivariate random-effects model with culture-based DST as reference standard. Main results We included 27 studies. Twenty-six studies evaluated version 1.0, and one study version 2.0. Of 26 studies stating specimen country origin, 15 studies (58%) evaluated patients from low- or middle-income countries. Overall, we considered the studies to be of high methodological quality. However, only three studies (11%) had low risk of bias for the reference standard; these studies used World Health Organization (WHO)-recommended critical concentrations for all drugs in the culture-based DST reference standard. MTBDRsl version 1.0 Fluoroquinolone resistance: indirect testing, MTBDRsl pooled sensitivity and specificity (95% confidence interval (CI)) were 85.6% (79.2% to 90.4%) and 98.5% (95.7% to 99.5%), (19 studies, 2223 participants); direct testing (smear-positive specimen), pooled sensitivity and specificity were 86.2% (74.6% to 93.0%) and 98.6% (96.9% to 99.4%), (nine studies, 1771 participants, moderate quality evidence). SLID resistance: indirect testing, MTBDRsl pooled sensitivity and specificity were 76.5% (63.3% to 86.0%) and 99.1% (97.3% to 99.7%), (16 studies, 1921 participants); direct testing (smear-positive specimen), pooled sensitivity and specificity were 87.0% (38.1% to 98.6%) and 99.5% (93.6% to 100.0%), (eight studies, 1639 participants, low quality evidence). Extensively drug-resistant tuberculosis: indirect testing, MTBDRsl pooled sensitivity and specificity were 70.9% (42.9% to 88.8%) and 98.8% (96.1% to 99.6%), (eight studies, 880 participants); direct testing (smear-positive specimen), pooled sensitivity and specificity were 69.4% (38.8% to 89.0%) and 99.4% (95.0% to 99.3%), (six studies, 1420 participants, low quality evidence). Similar to the original Cochrane review, we found no evidence of a significant difference in MTBDRsl version 1.0 accuracy between indirect and direct testing for fluoroquinolone resistance, SLID resistance, and extensively drug-resistant tuberculosis. MTBDRsl version 2.0 Fluoroquinolone resistance: direct testing, MTBDRsl sensitivity and specificity were 97% (83% to 100%) and 98% (93% to 100%), smear-positive specimen; 80% (28% to 99%) and 100% (40% to 100%), smear-negative specimen. SLID resistance: direct testing, MTBDRsl sensitivity and specificity were 89% (72% to 98%) and 90% (84% to 95%), smear-positive specimen; 80% (28% to 99%) and 100% (40% to 100%), smear-negative specimen. Extensively drug-resistant tuberculosis: direct testing, MTBDRsl sensitivity and specificity were 79% (49% to 95%) and 97% (93% to 99%), smear-positive specimen; 50% (1% to 99%) and 100% (59% to 100%), smear-negative specimen. We had insufficient data to estimate summary sensitivity and specificity of version 2.0 (smear-positive and -negative specimens) or to compare accuracy of the two versions. A limitation was that most included studies did not consistently use the World Health Organization (WHO)-recommended concentrations for drugs in the culture-based DST reference standard. Authors' conclusions In people with rifampicin-resistant or multidrug-resistant tuberculosis, MTBDRsl performed on a culture isolate or smear-positive specimen may be useful in detecting second-line drug resistance. MTBDRsl (smear-positive specimen) correctly classified around six in seven people as having fluoroquinolone or SLID resistance, although the sensitivity estimates for SLID resistance varied. The test rarely gave a positive result for people without drug resistance. However, when second-line drug resistance is not detected (MTBDRsl result is negative), conventional DST can still be used to evaluate patients for resistance to the fluoroquinolones or SLIDs. We recommend that future work evaluate MTBDRsl version 2.0, in particular on smear-negative specimens and in different settings to account for different resistance-causing mutations that may vary by strain. Researchers should also consider incorporating WHO-recommended critical concentrations into their culture-based reference standards.

OBJECTIVE: To examine whether a lipoarabinomannan (LAM) enzyme-linked immunosorbent assay (ELISA) that offers diagnostic utility using urine in patients with tuberculosis (TB) and human immunodeficiency virus (HIV) co-infection can be used in induced sputum to diagnose sputum-scarce patients with suspected TB. DESIGN: LAM was measured in induced sputum samples obtained from 61 consecutively recruited sputum-scarce TB suspects in a tertiary hospital respiratory clinic in South Africa. Liquid culture positivity for Mycobacterium tuberculosis was used as the reference standard. Receiver operating characteristic analysis was used to assess alternative LAM concentration cut-offs. RESULTS: A total of 87% (53/61) of study patients had a valid M. tuberculosis culture result; 49% (23/53) were HIV-infected and 17% (9/53) were culture-positive for M. tuberculosis. Induced sputum smear microscopy and LAM ELISA had an overall sensitivity of 56% (95%CI 27-81); however the specificity of LAM ELISA was 48% (95%CI 34-62) while the positive and negative predictive values were respectively 18% (95%CI 8-36) and 84% (95%CI 65-94). An optimal rule-in cut-off selected by receiver operating characteristic (LAM concentration >5.73 ng/ml) increased test specificity to 98% and reduced sensitivity to 22%. Normalisation of the assay for sample total protein or cell count did not improve diagnostic accuracy. CONCLUSIONS: In this proof-of-concept study the ELISA was not clinically useful for TB diagnosis using induced sputum.

Information regarding the utility of adjunct diagnostic tests in combination with Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) is limited. We hypothesised adjunct tests could enhance accuracy and/or reduce the cost of tuberculosis (TB) diagnosis prior to MTB/RIF testing, and rule-in or rule-out TB in MTB/RIF-negative individuals. We assessed the accuracy and/or laboratory-associated cost of diagnosis of smear microscopy, chest radiography (CXR) and interferon-γ release assays (IGRAs; T-SPOT-TB (Oxford Immunotec, Oxford, UK) and QuantiFERON-TB Gold In-Tube (Cellestis, Chadstone, Australia)) combined with MTB/RIF for TB in 480 patients in South Africa. When conducted prior to MTB/RIF: 1) smear microscopy followed by MTB/RIF (if smear negative) had the lowest cost of diagnosis of any strategy investigated; 2) a combination of smear microscopy, CXR (if smear negative) and MTB/RIF (if imaging compatible with active TB) did not further reduce the cost per TB case diagnosed; and 3) a normal CXR ruled out TB in 18% of patients (57 out of 324; negative predictive value (NPV) 100%). When downstream adjunct tests were applied to MTB/RIF-negative individuals, radiology ruled out TB in 24% (56 out of 234; NPV 100%), smear microscopy ruled in TB in 21% (seven out of 24) of culture-positive individuals and IGRAs were not useful in either context. In resource-poor settings, smear microscopy combined with MTB/RIF had the highest accuracy and lowest cost of diagnosis compared to either technique alone. In MTB/RIF-negative individuals, CXR has poor rule-in value but can reliably rule out TB in approximately one in four cases. These data inform upon the programmatic utility of MTB/RIF in high-burden settings.

Xpert MTB/RIF is a novel automated molecular diagnostic recently endorsed by the World Health Organization. However, performance-related data from high HIV prevalence settings are limited.The impact of sample-related factors on performance and the significance of Xpert MTB/RIF-positive culture-negative discordance remain unclear.Xpert MTB/RIF was evaluated using single archived spot-sputum samples from 496 South African patients with suspected TB. Mycobacterium tuberculosis culture positivity and phenotypic resistance to rifampicin served as reference standards.Overall, Xpert MTB/RIF detected 95% (95% confidence interval [CI], 88-98%; 89 of 94) of smear-positive culture-positive cases and the specificity was 94% (91-96%; 320 of 339). The sensitivity in smear-negative cases was 55% (35-73%; 12 of 22) when the analysis was restricted to 1 ml of unprocessed sputum and culture time-to-positivity of less than or equal to 28 days. Compared with smear microscopy (n=94), Xpert MTB/RIF detected an additional 17 cases (n=111) representing an 18% (11-27%; 111 vs. 94) relative increase in the rapid TB case detection rate. Moreover, compared with smear microscopy, the inclusion of Xpert MTB/RIF-positive culture-negative TB cases (ruled-in by an alternative diagnostic method) resulted in the detection of a further 16 cases (n=127), thus significantly increasing the rapid TB case detection rate to 35% (95% CI, 26-45%; 94 to 111 vs. 94 to 127; P0.01), the overall specificity to 99.1% (97-100%; 320 of 323; P0.001), and sensitivity in smear-negative TB to 60% (P=0.12). Performance strongly correlated with smear status and culture time-to-positivity. In patients infected with HIV compared with patients uninfected with HIV Xpert MTB/RIF showed a trend to reduced sensitivity (P=0.09) and significantly reduced negative predictive value (P=0.01). The negative predictive value for rifampicin resistance was 99.4%.XpertMTB/RIF outperformed smear microscopy, established a diagnosis in a significant proportion of patients with smear-negative TB, detected many highly likely TB cases missed by culture, and accurately ruled out rifampicin-resistant TB. Sample-specific factors had limited impact on performance. Performance in patients infected with HIV, especially those with advanced immunosuppression, warrants further study.

BACKGROUND: There are limited data about the epidemiology and treatment-related outcomes associated with capreomycin resistance in patients with XDR-TB. Capreomycin achieves high serum concentrations relative to MIC but whether capreomycin has therapeutic benefit despite microbiological resistance remains unclear. METHODS: We reviewed the susceptibility profiles and outcomes associated with capreomycin usage in patients diagnosed with XDR-TB between August 2002 and October 2012 in two provinces of South Africa. Patients whose isolates were genotypically tested for capreomycin resistance were included in the analysis. RESULTS: Of 178 XDR-TB patients 41% were HIV-infected. 87% (154/178) isolates contained a capreomycin resistance-conferring mutation [80% (143/178) rrs A1401G and 6% (11/178) were heteroresistant (containing both the rrs A1401G mutation and wild-type sequences)]. Previous MDR-TB treatment, prior usage of kanamycin, or strain type was not associated with capreomycin resistance. 92% (163/178) of XDR-TB patients were empirically treated with capreomycin. Capreomycin resistance decreased the odds of sputum culture conversion. In capreomycin sensitive and resistant persons combined weight at diagnosis was the only independent predictor for survival (p=

Background Accurate and rapid tests for tuberculosis (TB) drug resistance are critical for improving patient care and decreasing the transmission of drug-resistant TB. Genotype®MTBDRsl (MTBDRsl) is the only commercially-available molecular test for detecting resistance in TB to the fluoroquinolones (FQs; ofloxacin, moxifloxacin and levofloxacin) and the second-line injectable drugs (SLIDs; amikacin, kanamycin and capreomycin), which are used to treat patients with multidrug-resistant (MDR-)TB. Objectives To obtain summary estimates of the diagnostic accuracy of MTBDRsl for FQ resistance, SLID resistance and extensively drug-resistant TB (XDR-TB; defined as MDR-TB plus resistance to a FQ and a SLID) when performed (1) indirectly (ie on culture isolates confirmed as TB positive) and (2) directly (ie on smear-positive sputum specimens). To compare summary estimates of the diagnostic accuracy of MTBDRsl for FQ resistance, SLID resistance and XDR-TB by type of testing (indirect versus direct testing). The populations of interest were adults with drug-susceptible TB or drug-resistant TB. The settings of interest were intermediate and central laboratories. Search methods We searched the following databases without any language restriction up to 30 January 2014: Cochrane Infectious Diseases Group Specialized Register; MEDLINE; EMBASE; ISI Web of Knowledge; MEDION; LILACS; BIOSIS; SCOPUS; the metaRegister of Controlled Trials; the search portal of the World Health Organization International Clinical Trials Registry Platform; and ProQuest Dissertations & Theses A&I. Selection criteria We included all studies that determined MTBDRsl accuracy against a defined reference standard (culture-based drug susceptibility testing (DST), genetic testing or both). We included cross-sectional and diagnostic case-control studies. We excluded unpublished data and conference proceedings. Data collection and analysis For each study, two review authors independently extracted data using a standardized form and assessed study quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We performed meta-analyses to estimate the pooled sensitivity and specificity of MTBDRsl for FQ resistance, SLID resistance, and XDR-TB. We explored the influence of different reference standards. We performed the majority of analyses using a bivariate random-effects model against culture-based DST as the reference standard. Main results We included 21 unique studies: 14 studies reported the accuracy of MTBDRsl when done directly, five studies when done indirectly and two studies that did both. Of the 21 studies, 15 studies (71%) were cross-sectional and 11 studies (58%) were located in low-income or middle-income countries. All studies but two were written in English. Nine (43%) of the 21 included studies had a high risk of bias for patient selection. At least half of the studies had low risk of bias for the other QUADAS-2 domains. As a test for FQ resistance measured against culture-based DST, the pooled sensitivity of MTBDRsl when performed indirectly was 83.1% (95% confidence interval (CI) 78.7% to 86.7%) and the pooled specificity was 97.7% (95% CI 94.3% to 99.1%), respectively (16 studies, 1766 participants; 610 confirmed cases of FQ-resistant TB; moderate quality evidence). When performed directly, the pooled sensitivity was 85.1% (95% CI 71.9% to 92.7%) and the pooled specificity was 98.2% (95% CI 96.8% to 99.0%), respectively (seven studies, 1033 participants; 230 confirmed cases of FQ-resistant TB; moderate quality evidence). For indirect testing for FQ resistance, four (0.2%) of 1766 MTBDRsl results were indeterminate, whereas for direct testing 20 (1.9%) of 1033 were MTBDRsl indeterminate (P < 0.001). As a test for SLID resistance measured against culture-based DST, the pooled sensitivity of MTBDRsl when performed indirectly was 76.9% (95% CI 61.1% to 87.6%) and the pooled specificity was 99.5% (95% CI 97.1% to 99.9%), respectively (14 studies, 1637 participants; 414 confirmed cases of SLID-resistant TB; moderate quality evidence). For amikacin resistance, the pooled sensitivity and specificity were 87.9% (95% CI 82.1% to 92.0%) and 99.5% (95% CI 97.5% to 99.9%), respectively. For kanamycin resistance, the pooled sensitivity and specificity were 66.9% (95% CI 44.1% to 83.8%) and 98.6% (95% CI 96.1% to 99.5%), respectively. For capreomycin resistance, the pooled sensitivity and specificity were 79.5% (95% CI 58.3% to 91.4%) and 95.8% (95% CI 93.4% to 97.3%), respectively. When performed directly, the pooled sensitivity for SLID resistance was 94.4% (95% CI 25.2% to 99.9%) and the pooled specificity was 98.2% (95% CI 88.9% to 99.7%), respectively (six studies, 947 participants; 207 confirmed cases of SLID-resistant TB, 740 SLID susceptible cases of TB; very low quality evidence). For indirect testing for SLID resistance, three (0.4%) of 774 MTBDRsl results were indeterminate, whereas for direct testing 53 (6.1%) of 873 were MTBDRsl indeterminate (P < 0.001). As a test for XDR-TB measured against culture-based DST, the pooled sensitivity of MTBDRsl when performed indirectly was 70.9% (95% CI 42.9% to 88.8%) and the pooled specificity was 98.8% (95% CI 96.1% to 99.6%), respectively (eight studies, 880 participants; 173 confirmed cases of XDR-TB; low quality evidence). Authors' conclusions In adults with TB, a positive MTBDRsl result for FQ resistance, SLID resistance, or XDR-TB can be treated with confidence. However, MTBDRsl does not detect approximately one in five cases of FQ-resistant TB, and does not detect approximately one in four cases of SLID-resistant TB. Of the three SLIDs, MTBDRsl has the poorest sensitivity for kanamycin resistance. MTBDRsl will miss between one in four and one in three cases of XDR-TB. The diagnostic accuracy of MTBDRsl is similar when done using either culture isolates or smear-positive sputum. As the location of the resistance causing mutations can vary on a strain-by-strain basis, further research is required on test accuracy in different settings and, if genetic sequencing is used as a reference standard, it should examine all resistance-determining regions. Given the confidence one can have in a positive result, and the ability of the test to provide results within a matter of days, MTBDRsl may be used as an initial test for second-line drug resistance. However, when the test reports a negative result, clinicians may still wish to carry out conventional testing.

The determinants of Xpert MTB/RIF sensitivity, a widely used PCR test for the diagnosis of tuberculosis (TB) are poorly understood. We compared culture time-to-positivity (TTP; a surrogate of bacterial load), MTB/RIF TB-specific and internal positive control (IPC)-specific CT values and clinical characteristics in patients with suspected TB who provided expectorated (n = 438) or induced sputum (n = 128), tracheal aspirates (n = 71), bronchoalveolar lavage fluid (n = 152), pleural fluid (n = 76), cerebral spinal fluid (CSF; n = 152), pericardial fluid (n = 131), or urine (n = 173) specimens. Median bacterial load (TTP in days) was the strongest associate of MTB/RIF positivity in each fluid. TTP correlated with CT values in pulmonary specimens but not extrapulmonary specimens (Spearman's coefficient 0.5043 versus 0.1437; p = 0.030). Inhibition affected a greater proportion of pulmonary specimens than extrapulmonary specimens (IPC CT > 34: 6% (47/731) versus 1% (4/381; p < 0.0001). Pulmonary specimens had greater load than extrapulmonary specimens [TTPs (interquartile range) of 11 (7–16) versus 22 (18–33.5) days; p < 0.0001]. HIV-infection was associated with a decreased likelihood of MTB/RIF-positivity in pulmonary specimens but an increased likelihood in extrapulmonary specimens. Mycobacterial load, which displays significant variation across different body compartments, is the main determinant of MTB/RIF-positivity rather than PCR inhibition. MTB/RIF CT is a poor surrogate of load in extrapulmonary specimens.

Background: The accuracy of currently available same-day diagnostic tools (smear microscopy and conventional nucleic acid amplification tests) for pleural tuberculosis (TB) is sub-optimal. Newer technologies may offer improved detection. Methods: Smear-microscopy, adenosine deaminase (ADA), interferon gamma (IFN-γ), and Xpert MTB/RIF [using an unprocessed (1 ml) and centrifuged (~20 ml) sample] test accuracy was evaluated in pleural fluid from 103 consecutive patients with suspected pleural TB. Culture for M.tuberculosis and/or histopathology (pleural biopsy) served as the reference standard. Patients were followed prospectively to determine their diagnostic categorisation. Results: Of 93 evaluable participants, 40 had definite-TB (reference positive), 5 probable-TB (not definite but treated for TB) and 48 non-TB (culture and histology negative, and not treated for TB). Xpert MTB/RIF sensitivity and specificity (95% CI) was 22.5% (12.4 - 37.6) and 98% (89.2 - 99.7), respectively, and centrifugation did not improve sensitivity (23.7%). The Xpert MTB/RIF internal positive control showed no evidence of inhibition. Biomarker specific sensitivity, specificity, PPV, and NPVs were: ADA (48.85 IU/L; rule-in cut-point) 55.3% (39.8 - 69.9), 95.2% (83.9 - 98.7), 91.4 (73.4 - 95.4), 69.7% (56.7 - 80.1); ADA (30 IU/L; clinically used cut-point) 79% (63.7 - 89), 92.7% (80.6 - 97.5), 91.0 (73.4 - 95.4), 82.7% (69.3 - 90.1); and IFN-γ (107.7 pg/ml; rule-in cut-point) 92.5% (80.2 - 97.5), 95.9% (86.1 - 98.9), 94.9% (83.2 - 98.6), 93.9% (83.5 - 97.9), respectively (IFN-γ sensitivity and NPV better than Xpert [p

The accuracy and impact of new tuberculosis (TB) tests, such as Xpert MTB/RIF, when performed on bronchoalveolar lavage fluid (BALF) obtained from patients with sputum-scarce or smear-negative TB is unclear.South African patients with suspected pulmonary TB (n=160) who were sputum-scarce or smear-negative underwent bronchoscopy. MTB/RIF was performed on uncentrifuged BALF (1 ml) and/or a resuspended pellet of centrifuged BALF (∼10 ml). Time to TB detection and anti-TB treatment initiation were compared between phase one, when MTB/RIF was performed as a research tool, and phase two, when it was used for patient management.27 of 154 patients with complete data had culture-confirmed TB. Of these, a significantly lower proportion were detected by smear microscopy compared with MTB/RIF (58%, 95% CI 39% to 75% versus 93%, 77% to 98%; p0.001). Of the 127 patients who were culture negative, 96% (91% to 98%) were MTB/RIF negative. When phase two was compared with phase one, MTB/RIF reduced the median days to TB detection (29 (18-41) to 0 (0-0); p0.001). However, more patients initiated empirical therapy (absence of a positive test in those commencing treatment) in phase one versus phase two (79% (11/14) versus 28% (10/25); p=0.026). Consequently, there was no detectable difference in the overall proportion of patients initiating treatment (26% (17/67; 17% to 37%) versus 36% (26/73; 26% to 47%); p=0.196) or the days to treatment initiation (10 (1-49) versus 7 (0-21); p=0.330). BALF centrifugation, HIV coinfection and a second MTB/RIF did not result in detectable changes in accuracy.MTB/RIF detected TB cases more accurately and more rapidly than smear microscopy and significantly reduced the rate of empirical treatment.

We would like to congratulate Catharina Boehme and colleagues (April 30, p 1495) on their study, the results of which show the excellent performance of Xpert MTB/RIF in health facilities in high-burden, resource-poor settings. The sensitivity of Xpert MTB/RIF was not reduced in individuals infected with HIV compared with those who were uninfected and convincingly outperformed smear microscopy. Thus, Xpert MTB/RIF represents a fundamental advance in the diagnosis of tuberculosis. We have shown a diminished negative predictive value (NPV) and negative likelihood ratio (LR) of Xpert MTB/RIF for the detection of tuberculosis in individuals infected with HIV versus those who were uninfected, suggesting that substantial numbers of patients infected with HIV who are negative by Xpert MTB/RIF actually have active tuberculosis. The likelihood of this false-negativity occurring increased with advanced immunosuppression. The conclusiveness of our fi ndings was limited by our retrospective study design and small sample size. However, these data have now been prospectively confi rmed in 6648 patients by Boehme and colleagues. In their study, the NPV was 91·3% (389/426; 95% CI 88·3–93·6) in patients infected with HIV versus 96·0% (748/779; 94·4–97·2; p

Background The successful cure of tuberculosis (TB) is dependent on adherence to treatment. Various factors influence adherence, however, few are easily modifiable. There are limited data regarding correlates of psychological distress and their association with non-adherence to anti-TB treatment. Methods In a trial of a new TB test, we measured psychological distress (K-10 score), TB-related health literacy, and morbidity (TBscore), prior to diagnosis in 1502 patients with symptoms of pulmonary TB recruited from clinics in Cape Town (n = 419), Harare (n = 400), Lusaka (n = 400), Durban (n = 200), and Mbeya (n = 83). Socioeconomic, demographic, and alcohol usage-related data were captured. Patients initiated on treatment had their DOTS cards reviewed at two-and six-months. Results 22 %(95 % CI: 20 %, 25 %) of patients had severe psychological distress (K-10 ≥ 30). In a multivariable linear regression model, increased K-10 score was independently associated with previous TB [estimate (95 % CI) 0.98(0.09-1.87); p = 0.0304], increased TBscore [1(0.80, 1.20); p