Nontuberculous mycobacterial (NTM) infections in bronchiectasis patients: A retrospective US registry cohort study.

RATIONALE: Longitudinal epidemiological and clinical data are needed to improve the management of patients with bronchiectasis developing nontuberculous mycobacterial (NTM) pulmonary disease. OBJECTIVES: To describe the epidemiology, patient management, and treatment outcomes of NTM infections in patients with bronchiectasis enrolled in the United States Bronchiectasis and NTM Research Registry (US BRR). METHODS: This was a retrospective cohort study of patients with bronchiectasis and NTM infections enrolled with follow-up in the US BRR in 2008-2019. The study included patients with ≥1 positive NTM respiratory culture in the 24-month baseline period (baseline NTM cohort) and/or during the annual follow-up visits (incident NTM cohort). Incidence, prevalence, baseline patient characteristics, treatment exposure, treatment outcomes, and respiratory clinical outcomes were described in the baseline NTM cohort, incident NTM cohort, and both cohorts combined (prevalent NTM cohort). RESULTS: Between 2008 and 2019, 37.9% (1457/3840) of patients with bronchiectasis in the US BRR met the inclusion criteria for this study and were reported to have Mycobacterium avium complex (MAC) and/or Mycobacterium abscessus complex (MABSC) infections. MAC prevalence increased steadily in the US BRR during 2009-2019; incidence was relatively stable, except for a peak in 2011 followed by a slow decrease. MABSC and mixed MAC/MABSC infections were rare. Most patients with bronchiectasis and NTM infections in the registry were female, White, and aged >65 years. The antibiotics administered most commonly reflected current guidelines. In the prevalent cohort, 44.9% of MAC infections and 37.1% of MABSC infections remained untreated during follow-up, and MAC treatment was initiated with delay (>90 days after positive NTM respiratory culture) twice as frequently as promptly (≤90 days after positive NTM respiratory culture) (68.6% vs 31.4%, respectively). The median time from diagnosis to treatment was shorter for MABSC versus MAC infections (194.0 days [interquartile range (IQR) 8.0, 380.0] vs 296.0 days [IQR 35.0, 705.0], respectively). Among patients with MAC infections who completed treatment, 27.6% were classified as cured and 29.6% as treatment failure during the annual follow-up visit window. For MABSC, these proportions were 25.0% and 28.0%, respectively. CONCLUSIONS: A considerable proportion of MAC and MABSC infections were untreated or treated after initial delay/observation. MABSC infections were more likely to be treated and start treatment sooner than MAC infections. Further longitudinal studies are warranted to evaluate the monitor-with-delay approach and inform clinical guidelines.

Evidence-based Definition for Extensively Drug-Resistant Tuberculosis.

Rationale: Until 2020, extensively drug-resistant tuberculosis (XDR-TB) was defined as TB with resistance to rifampicin and isoniazid (multidrug-resistant TB [MDR-TB]), any fluoroquinolone (FQ), and any second-line injectable drug (SLID). In 2019, the World Health Organization issued new recommendations for treating patients with drug-resistant TB, substantially limiting the role of SLIDs in MDR-TB treatment and thus putting the definition of XDR-TB into question. Objectives: To propose an up-to-date definition for XDR-TB. Methods: We used a large data set to assess treatment outcomes for patients with MDR-TB exposed to any type of longer regimen. We included patients with bacteriologically confirmed MDR-TB and known FQ and SLID resistance results. We performed logistic regression to estimate the adjusted odds ratios (aORs) for an unfavorable treatment outcome (failure, relapse, death, loss to follow-up), and estimates were stratified by the resistance pattern (FQ and/or SLID) and group A drug use (moxifloxacin/levofloxacin, linezolid, and/or bedaquiline). Measurements and Main Results: We included 11,666 patients with MDR-TB; 4,653 (39.9%) had an unfavorable treatment outcome. Resistance to FQs increased the odds of an unfavorable treatment outcome (aOR, 1.91; 95% confidence interval [CI], 1.63-2.23). Administration of bedaquiline and/or linezolid improved treatment outcomes regardless of resistance to FQs and/or SLIDs. Among patients with XDR-TB, compared with persons receiving no group A drug, aORs for an unfavorable outcome were 0.37 (95% CI, 0.20-0.69) with linezolid only, 0.40 (95% CI, 0.21-0.77) with bedaquiline only, and 0.21 (95% CI, 0.12-0.38) with both. Conclusions: Our study supports a new definition of XDR-TB as MDR-TB and additional resistance to FQ plus bedaquiline and/or linezolid and helps assess the adequacy of this definition for surveillance and treatment choice.

Diagnostic pitfalls of urogenital tuberculosis.

OBJECTIVES: To describe characteristics, details of diagnosis and outcomes of urogenital tuberculosis (UGTB) in a low-prevalence country. METHODS: We conducted a retrospective observational study of 37 consecutive patients diagnosed with UGTB between 1st January 2014 and 31st October 2019 in an East London hospital. RESULTS: 68% (25/37) of patients were male and the median age was 42 years (IQR 34-55). 89% (33/37) of patients were born outside the United Kingdom with 65% (24/37) born in the South Asian region. Renal (32.4%), epididymal (24.3%) and endometrial TB (21.6%) were the most prevalent forms of UGTB. Only 13.5% of UGTB patients had concurrent pulmonary TB. The median length of time from symptom onset to treatment was 163 days, while endometrial TB had an average delay to diagnosis of 564 days. Approximately half of patients with UGTB were culture positive (51.4%). However, 70% of early morning urines (EMUs) sent in urinary TB were culture positive. 11 patients (30.6%) underwent two or more invasive procedures, such as biopsy to obtain specimen samples. The mean treatment length for all UGTB cases was 7.3 months (SD 3.1). Notably, 25% of patients with endometrial TB required surgery despite antituberculous treatment. CONCLUSIONS: UGTB is challenging to diagnose as early disease is often asymptomatic. Clinicians faced with non-specific symptoms, or features suggestive of urogenital malignancy amongst patients from TB-endemic areas, should maintain a high suspicion of UGTB.

Atypical mycobacterial infections - management and when to treat.

PURPOSE OF REVIEW: Infections caused by nontuberculous mycobacteria (NTM) are increasing for several reasons, including diagnostic advances, increased awareness and a larger at-risk population. NTM pulmonary disease is surpassing tuberculosis (TB) in some low incidence areas. This review summarizes the latest literature and guidelines and aims to be a concise source outlining treatment and management of NTM lung infections, integrating established treatment paradigms with novel pharmacological interventions. RECENT FINDINGS: Recent additions to NTM treatment are inhaled liposomal amikacin and the anti-TB drug bedaquiline. Several other new or repurposed treatments are being explored in vitro, in animal models and in clinical trials, including novel beta-lactamase inhibitor/lactam combinations, dual-lactam combinations, efflux pump inhibitors, novel antimicrobials, inhaled clofazimine suspension and bacteriophages. SUMMARY: Patients with NTM pulmonary disease are mainly female and older with significant delay between diagnosis and treatment being common. Treatment varies according to causative organism, drug susceptibilities, radiological type and disease severity. Underlying chronic conditions, drug intolerances and interactions require careful consideration. In all cases, at least three drugs should be used to minimize acquisition of drug resistance, and all patients should receive a minimum of 12 months of treatment. Expert advice should be taken. NTM treatment is longer than TB treatment, more likely to fail and more likely to cause toxicity. The relatively small numbers of patients affected by each NTM species has limited research. Novel treatments hold promise; nevertheless, it is likely that new solutions for NTM management will stem from the TB pipeline for the foreseeable future.

Epidemic and pandemic viral infections: impact on tuberculosis and the lung: A consensus by the World Association for Infectious Diseases and Immunological Disorders (WAidid), Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases Study Group for Mycobacterial Infections (ESGMYC).

Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Breast tuberculosis in East London: A 13-year retrospective observational study.

SETTING: Breast tuberculosis (TB) is rare in Western Europe, and its diagnosis may be delayed through lack of awareness of presenting features. Our institution serves a large East London population with a high incidence of TB. OBJECTIVE: To characterize presenting features and avoidable diagnostic delay in breast TB patients. DESIGN: We conducted a 13-year retrospective study of breast TB patients treated at our institution including demographic, clinical, microbiology, and pathology data. RESULTS: Forty-seven cases were included; 44 (94%) were female, with a median age of 33 years (IQR 28.5-39.5). The main presenting feature was a breast lump in 41 cases (87%); which were predominantly solitary unilateral lesions (25, 61%) and frequently located in the upper outer quadrant (28, 68%). Where performed, Mycobacterium tuberculosis was cultured in 15/36 (42%) cases. Granulomata were present on biopsy or aspirate in 21 (47%) and 17 (36%) cases, respectively. The median duration between symptom onset and treatment was 20 weeks (IQR 15-30). Forty-six (98%) completed treatment successfully and one relapsed. CONCLUSION: A high index of suspicion for TB is required for individuals presenting with breast symptoms from countries where TB is endemic. Development of standardized pathways may improve detection and management of breast TB may reduce diagnostic delay.

Necrotizing pneumonia (aetiology, clinical features and management).

PURPOSE OF REVIEW: Necrotizing pneumonia is a severe form of community-acquired pneumonia characterized by rapid progression of consolidation to necrosis and cavitation which may lead to pulmonary gangrene. Morbidity and mortality are high and chronic sequelae are frequent. The lack of guidance supports the review of the latest recommendations in the management of these pneumonias. RECENT FINDINGS: Antibiotic therapy alone may not be enough to alter the course of the infection, and regimens, adjunctive therapies like intravenous immunoglobulins, surgery may be required to alter the course of the disease especially with pulmonary gangrene. SUMMARY: The causative agents, clinical features and management of necrotizing pneumonias are discussed.

Clinical Management of Multidrug-Resistant Tuberculosis in 16 European Countries.

RATIONALE: Multidrug-resistant tuberculosis (MDR-TB) is a major burden to public health in Europe. Reported treatment success rates are around 50% or less, and cure rates are even lower. OBJECTIVES: To document the management and treatment outcome in patients with MDR-TB in Europe. METHODS: We performed a prospective cohort study, analyzing management and treatment outcomes stratified by incidence of patients with MDR-TB in Europe. Treatment outcomes were compared by World Health Organization and alternative simplified definitions by the Tuberculosis Network European Trialsgroup (TBNET). MEASUREMENTS AND MAIN RESULTS: A total of 380 patients with MDR-TB were recruited and followed up between 2010 and 2014 in 16 European countries. Patients in high-incidence countries compared with low-incidence countries were treated more frequently with standardized regimen (83.2% vs. 9.9%), had delayed treatment initiation (median, 111 vs. 28 d), developed more additional drug resistance (23% vs. 5.8%), and had increased mortality (9.4% vs. 1.9%). Only 20.1% of patients using pyrazinamide had proven susceptibility to the drug. Applying World Health Organization outcome definitions, frequency of cure (38.7% vs. 9.7%) was higher in high-incidence countries. Simplified outcome definitions that include 1 year of follow-up after the end of treatment showed similar frequency of relapse-free cure in low- (58.3%), intermediate- (55.8%), and high-incidence (57.1%) countries, but highest frequency of failure in high-incidence countries (24.1% vs. 14.6%). CONCLUSIONS: Conventional standard MDR-TB treatment regimens resulted in a higher frequency of failure compared with individualized treatments. Overall, cure from MDR-TB is substantially more frequent than previously anticipated, and poorly reflected by World Health Organization outcome definitions.

ERS/ECDC Statement: European Union standards for tuberculosis care, 2017 update.

The International Standards for Tuberculosis Care define the essential level of care for managing patients who have or are presumed to have tuberculosis, or are at increased risk of developing the disease. The resources and capacity in the European Union (EU) and the European Economic Area permit higher standards of care to secure quality and timely TB diagnosis, prevention and treatment. On this basis, the European Union Standards for Tuberculosis Care (ESTC) were published in 2012 as standards specifically tailored to the EU setting. Since the publication of the ESTC, new scientific evidence has become available and, therefore, the standards were reviewed and updated.A panel of international experts, led by a writing group from the European Respiratory Society (ERS) and the European Centre for Disease Prevention and Control (ECDC), updated the ESTC on the basis of new published evidence. The underlying principles of these patient-centred standards remain unchanged. The second edition of the ESTC includes 21 standards in the areas of diagnosis, treatment, HIV and comorbidities, and public health and prevention.The ESTC target clinicians and public health workers, provide an easy-to-use resource and act as a guide through all the required activities to ensure optimal diagnosis, treatment and prevention of TB.

Direct Whole-Genome Sequencing of Sputum Accurately Identifies Drug-Resistant Mycobacterium tuberculosis Faster than MGIT Culture Sequencing.

The current methods available to diagnose antimicrobial-resistant Mycobacterium tuberculosis infections require a positive culture or only test a limited number of resistance-associated mutations. A rapid accurate identification of antimicrobial resistance enables the prompt initiation of effective treatment. Here, we determine the utility of whole-genome sequencing (WGS) of M. tuberculosis directly from routinely obtained diagnostic sputum samples to provide a comprehensive resistance profile compared to that from mycobacterial growth indicator tube (MGIT) WGS. We sequenced M. tuberculosis from 43 sputum samples by targeted DNA enrichment using the Agilent SureSelectXT kit, and 43 MGIT positive samples from each participant. Thirty two (74%) sputum samples and 43 (100%) MGIT samples generated whole genomes. The times to antimicrobial resistance profiles and concordance were compared with Xpert MTB/RIF and phenotypic resistance testing from cultures of the same samples. Antibiotic susceptibility could be predicted from WGS of sputum within 5 days of sample receipt and up to 24 days earlier than WGS from MGIT culture and up to 31 days earlier than phenotypic testing. Direct sputum results could be reduced to 3 days with faster hybridization and if only regions encoding drug resistance are sequenced. We show that direct sputum sequencing has the potential to provide comprehensive resistance detection significantly faster than MGIT whole-genome sequencing or phenotypic testing of resistance from cultures in a clinical setting. This improved turnaround time enables prompt appropriate treatment with associated patient and health service benefits. Improvements in sample preparation are necessary to ensure comparable sensitivities and complete resistance profile predictions in all cases.

Linezolid pharmacokinetics in MDR-TB: a systematic review, meta-analysis and Monte Carlo simulation.

Objectives: The oxazolidinone linezolid is an effective component of drug-resistant TB treatment, but its use is limited by toxicity and the optimum dose is uncertain. Current strategies are not informed by clinical pharmacokinetic (PK)/pharmacodynamic (PD) data; we aimed to address this gap. Methods: We defined linezolid PK/PD targets for efficacy (fAUC0-24:MIC >119 mg/L/h) and safety (fCmin <1.38 mg/L). We extracted individual-level linezolid PK data from existing studies on TB patients and performed meta-analysis, producing summary estimates of fAUC0-24 and fCmin for published doses. Combining these with a published MIC distribution, we performed Monte Carlo simulations of target attainment. Results: The efficacy target was attained in all simulated individuals at 300 mg q12h and 600 mg q12h, but only 20.7% missed the safety target at 300 mg q12h versus 98.5% at 600 mg q12h. Although suggesting 300 mg q12h should be used preferentially, these data were reliant on a single centre. Efficacy and safety targets were missed by 41.0% and 24.2%, respectively, at 300 mg q24h and by 44.6% and 27.5%, respectively, at 600 mg q24h. However, the confounding effect of between-study heterogeneity on target attainment for q24h regimens was considerable. Conclusions: Linezolid dosing at 300 mg q12h may retain the efficacy of the 600 mg q12h licensed dosing with improved safety. Data to evaluate commonly used 300 mg q24h and 600 mg q24h doses are limited. Comprehensive, prospectively obtained PK/PD data for linezolid doses in drug-resistant TB treatment are required.

Single-center outbreak of Pneumocystis jirovecii pneumonia in heart transplant recipients.

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) outbreaks are described in solid organ transplant recipients. Few reports suggest interhuman transmission with important infection control implications. We described a large PJP outbreak in heart transplant (HTx) recipients. METHODS: Six cases of PJP occurred in HTx recipients within 10 months in our hospital. Demographics, clinical characteristics, treatment and outcomes were described. To identify contacts among individuals a review of all dates of out-patient visits and patient hospitalizations was performed. Cross exposure was also investigated using genotyping on PJ isolates. RESULTS: At the time of PJP-related hospitalization, patients' mean age was 49 ± standard deviation 4 years, median time from HTx was 8 (25%-75% interquartile range [Q1-Q3] 5-12) months and none of the cases were on prophylaxis. At PJP-related admission, 5 patients had CMV reactivation, of whom 4 were on antiviral preemptive treatment. Median in-hospital stay was 30 (Q1-Q3, 28-48) days; and 2 cases required intensive care unit admission. All patients survived beyond 2 years. Transmission map analysis suggested interhuman transmission in all cases (presumed incubation period, median 90 [Q1-Q3, 64-91] days). Genotyping was performed in 4 cases, demonstrating the same PJ strain in 3 cases. CONCLUSIONS: We described a large PJP cluster among HTx recipients, supporting the nosocomial acquisition of PJP through interhuman transmission. Based on this experience, extended prophylaxis for more than 6 months after HTx could be considered in specific settings. Further work is required to understand its optimal duration and timing based on individual risk factor profiles and to define standardized countermeasures to prevent and limit PJP outbreaks.

Bedaquiline and Delamanid Combination Treatment of 5 Patients with Pulmonary Extensively Drug-Resistant Tuberculosis.

We report the experiences of 5 patients taking bedaquiline with delamanid in combination: 1 patient was cured; 3 culture converted, with 2 continuing and 1 changing therapy; and 1 died from respiratory insufficiency. For 2 patients, QT-interval prolongation but no arrhythmias occurred. Use of this therapy is justified for patients with limited options.

Effectiveness and safety of bedaquiline-containing regimens in the treatment of MDR- and XDR-TB: a multicentre study.

Large studies on bedaquiline used to treat multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB) are lacking. This study aimed to evaluate the safety and effectiveness of bedaquiline-containing regimens in a large, retrospective, observational study conducted in 25 centres and 15 countries in five continents.428 culture-confirmed MDR-TB cases were analysed (61.5% male; 22.1% HIV-positive, 45.6% XDR-TB). MDR-TB cases were admitted to hospital for a median (interquartile range (IQR)) 179 (92-280) days and exposed to bedaquiline for 168 (86-180) days. Treatment regimens included, among others, linezolid, moxifloxacin, clofazimine and carbapenems (82.0%, 58.4%, 52.6% and 15.3% of cases, respectively).Sputum smear and culture conversion rates in MDR-TB cases were 63.6% and 30.1%, respectively at 30 days, 81.1% and 56.7%, respectively at 60 days; 85.5% and 80.5%, respectively at 90 days and 88.7% and 91.2%, respectively at the end of treatment. The median (IQR) time to smear and culture conversion was 34 (30-60) days and 60 (33-90) days. Out of 247 culture-confirmed MDR-TB cases completing treatment, 71.3% achieved success (62.4% cured; 8.9% completed treatment), 13.4% died, 7.3% defaulted and 7.7% failed. Bedaquiline was interrupted due to adverse events in 5.8% of cases. A single case died, having electrocardiographic abnormalities that were probably non-bedaquiline related.Bedaquiline-containing regimens achieved high conversion and success rates under different nonexperimental conditions.

Combined Use of Delamanid and Bedaquiline to Treat Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis: A Systematic Review.

The new drugs delamanid and bedaquiline are increasingly being used to treat multidrug-resistant (MDR-) and extensively drug-resistant tuberculosis (XDR-TB). The World Health Organization, based on lack of evidence, recommends their use under specific conditions and not in combination. No systematic review has yet evaluated the efficacy, safety, and tolerability of delamanid and bedaquiline used in combination. A search of peer-reviewed, scientific evidence was carried out, aimed at evaluating the efficacy/effectiveness, safety, and tolerability of delamanid and bedaquiline-containing regimens in individuals with pulmonary/extrapulmonary disease, which were bacteriologically confirmed as M/XDR-TB. We used PubMed to identify any relevant manuscripts in English up to the 23 December 2016, excluding editorials and reviews. Three out of 75 manuscripts retrieved satisfied the inclusion criteria, whilst 72 were excluded for dealing with only one drug (three studies), being recommendations (one study) or identifying need for their use (one study), focusing on drug resistance aspects (six studies) or being generic reviews/other studies (61 papers). The studies retrieved reported two XDR-TB cases observed for six months and achieving consistent sputum smear and culture conversion. Case 2 experienced a short break of bedaquiline, which was re-started after introducing verapamil. After a transient and symptom-free increase of the QT interval from week 5 to 17, it then decreased below the 500 ms threshold.

Effectiveness and safety of meropenem/clavulanate-containing regimens in the treatment of MDR- and XDR-TB.

No large study has ever evaluated the efficacy, safety and tolerability of meropenem/clavulanate to treat multidrug- and extensively drug-resistant tuberculosis (MDR- and XDR-TB). The aim of this observational study was to evaluate the therapeutic contribution, effectiveness, safety and tolerability profile of meropenem/clavulanate added to a background regimen when treating MDR- and XDR-TB cases.Patients treated with a meropenem/clavulanate-containing regimen (n=96) showed a greater drug resistance profile than those exposed to a meropenem/clavulanate-sparing regimen (n=168): in the former group XDR-TB was more frequent (49% versus 6.0%, p<0.0001) and the median (interquartile range (IQR)) number of antibiotic resistances was higher (8 (6-9)versus 5 (4-6)). Patients were treated with a meropenem/clavulanate-containing regimen for a median (IQR) of 85 (49-156) days.No statistically significant differences were observed in the overall MDR-TB cohort and in the subgroups with and without the XDR-TB patients; in particular, sputum smear and culture conversion rates were similar in XDR-TB patients exposed to meropenem/clavulanate-containing regimens (88.0% versus 100.0%, p=1.00 and 88.0% versus 100.0%, p=1.00, respectively). Only six cases reported adverse events attributable to meropenem/clavulanate (four of them then restarting treatment).The nondifferent outcomes and bacteriological conversion rate observed in cases who were more severe than controls might imply that meropenem/clavulanate could be active in treating MDR- and XDR-TB cases.

Comparison of effectiveness and safety of imipenem/clavulanate- versus meropenem/clavulanate-containing regimens in the treatment of MDR- and XDR-TB.

No large study to date has ever evaluated the effectiveness, safety and tolerability of imipenem/clavulanate versus meropenem/clavulanate to treat multidrug- and extensively drug-resistant tuberculosis (MDR- and XDR-TB). The aim of this observational study was to compare the therapeutic contribution of imipenem/clavulanate versus meropenem/clavulanate added to background regimens to treat MDR- and XDR-TB cases.84 patients treated with imipenem/clavulanate-containing regimens showed a similar median number of antibiotic resistances (8 versus 8) but more fluoroquinolone resistance (79.0% versus 48.9%, p<0.0001) and higher XDR-TB prevalence (67.9% versus 49.0%, p=0.01) in comparison with 96 patients exposed to meropenem/clavulanate-containing regimens. Patients were treated with imipenem/clavulanate- and meropenem/clavulanate-containing regimens for a median (interquartile range) of 187 (60-428) versus 85 (49-156) days, respectively.Statistically significant differences were observed on sputum smear and culture conversion rates (79.7% versus 94.8%, p=0.02 and 71.9% versus 94.8%, p<0.0001, respectively) and on success rates (59.7% versus 77.5%, p=0.03). Adverse events to imipenem/clavulanate and meropenem/clavulanate were reported in 5.4% and 6.5% of cases only.Our study suggests that meropenem/clavulanate is more effective than imipenem/clavulanate in treating MDR/XDR-TB patients.