Protecting the tuberculosis drug pipeline: stating the case for the rational use of fluoroquinolones

Transmission of fluoroquinolones resistance among multidrug-resistant tuberculosis in Shanghai, China: a retrospective population-based genomic epidemiology study

Fluoroquinolones (FQ) are essential for the treatment of multidrug-resistant tuberculosis (MDR-TB). The FQ resistance (FQ-R) rate in MDR-TB in China and its risk factors remain poorly understood. We conducted a retrospective, population-based genomic epidemiology study of MDR-TB patients in Shanghai, China, from 2009 to 2018. A genomic cluster was defined as strains with genetic distances ≤ 12 single nucleotide polymorphisms. The transmitted FQ-R was defined as the same FQ resistance-conferring mutations shared by ≥ 2 strains in a genomic cluster. We used multivariable logistic regression analysis to identify the risk factors for drug resistance. Among the total 850 MDR-TB patients included in the study, 72.8% (619/850) were male, the median age was 39 (interquartile range 28, 55) years, 52.7% (448/850) were migrants, and 34.5% (293/850) were previously treated patients. Most of the MDR-TB strains belong to the Beijing lineage (91.7%, 779/850). Overall, the genotypic resistance rate of FQ was 34.7% (295/850), and 47.1% (139/295) FQ-R patients were in genomic clusters, of which 98 (33.2%, 98/295) were presumed as transmitted FQ-R. Patients with treatment-naïve (aOR = 1.84; 95% CI: 1.09, 3.16), diagnosed in a district-level hospital (aOR = 2.69; 95% CI: 1.56, 4.75), and streptomycin resistance (aOR = 3.69; 95% CI: 1.65, 9.42) were significantly associated with the transmission of FQ-R. In summary, the prevalence of FQ-R among MDR-TB patients was high in Shanghai, and at least one-third were transmitted. Enforced interventions including surveillance of FQ drug susceptibility testing and screening among MDR-TB before initiation of treatment were urgently needed.

Do private providers initiate anti-tuberculosis therapy on the basis of chest radiographs? A standardised patient study in urban India

Background

The initiation of anti-tuberculosis treatment (ATT) based on results of WHO-approved microbiological diagnostics is an important marker of quality tuberculosis (TB) care. Evidence suggests that other diagnostic processes leading to treatment initiation may be preferred in high TB incidence settings. This study examines whether private providers start anti-TB therapy on the basis of chest radiography (CXR) and clinical examinations.

Methods

This study uses the standardized patient (SP) methodology to generate accurate and unbiased estimates of private sector, primary care provider practice when a patient presents a standardized TB case scenario with an abnormal CXR. Using multivariate log-binomial and linear regressions with standard errors clustered at the provider level, we analyzed 795 SP visits conducted over three data collection waves from 2014 to 2020 in two Indian cities. Data were inverse-probability-weighted based on the study sampling strategy, resulting in city-wave-representative results.

Findings

Amongst SPs who presented to a provider with an abnormal CXR, 25% (95% CI: 21-28%) visits resulted in ideal management, defined as the provider prescribing a microbiological test and not offering a concurrent prescription for a corticosteroid or antibiotic (including anti-TB medications). In contrast, 23% (95% CI: 19-26%) of 795 visits were prescribed anti-TB medications. Of 795 visits, 13% (95% CI: 10-16%) resulted in anti-TB treatment prescriptions/dispensation and an order for confirmatory microbiological testing.

Interpretation

One in five SPs presenting with abnormal CXR were prescribed ATT by private providers. This study contributes novel insights to empiric treatment prevalence based on CXR abnormality. Further work is needed to understand how providers make trade-offs between existing diagnostic practices, new technologies, profits, clinical outcomes, and the market dynamics with laboratories.

Funding

This study was funded by the Bill & Melinda Gates Foundation (grant OPP1091843), and the Knowledge for Change Program at The World Bank.

Whole-genome sequencing for surveillance of fluoroquinolone resistance in rifampicin-susceptible tuberculosis in a rural district of Shanghai: A 10-year retrospective study

Background

Fluoroquinolones (FQs) are the most important second-line anti-tuberculosis (anti-TB) drugs, primarily used for the treatment of multidrug- or rifampicin-resistant TB (MDR/RR-TB). However, FQs are also commonly used to treat other bacterial infections. There are few published data on the rates of FQ resistance among rifampicin-susceptible TB.

Methods

We used whole-genome sequencing (WGS) to determine the prevalence of FQ resistance among rifampicin-susceptible TB in a rural district of Shanghai. This was a population-based retrospective study of all culture-positive pulmonary TB patients diagnosed in the Chongming district of Shanghai, China during 2009-2018.

Results

The rate of FQ resistance was 8.4% (29/345) among TB, 6.2% (20/324) among rifampicin-susceptible TB, and 42.9% (9/21) among MDR/RR-TB. Transmission of FQ-resistant strains was defined as strains differing within 12 single-nucleotide polymorphisms (SNPs) based on WGS. Among the rifampicin-susceptible TB, 20% (4/20) of FQ resistance was caused by the transmission of FQ-resistant strains and 45% (9/20) of FQ resistance was identified as hetero-resistance.

Conclusions

The prevalence of FQ resistance in rifampicin-susceptible TB was higher than expected in Shanghai. Both the transmission and the selection of drug-resistant strains drive the emergence of FQ resistance in rifampicin-susceptible TB isolates. Therefore, the WGS-based surveillance system for TB should be urgently established and the clinical awareness of the rational use of FQs for respiratory infections should be enhanced to prevent the premature occurrence of FQ resistance.

What are the Tuberculosis Care Practices of Informal Healthcare Providers? A Cross-Sectional Study from Eastern India

India is the highest Tuberculosis (TB) burden country, accounting for an estimated 26 % of the global burden of disease. Systematic engagement of the private sector is a cornerstone of India's National Strategic Plan (NSP) for TB elimination (2017-2025). However, Informal Healthcare Providers (IPs), who are the first point of contact for a large number of TB patients, remain significantly underutilised in the National TB Elimination Program (NTEP) of India. Non-prioritisation of IPs has also resulted in a limited understanding of their TB care practices in the community. We, therefore, undertook a descriptive study to document IPs' TB care practices, primarily focusing on their approach to screening, diagnosis, treatment, and referral. This cross-sectional study was carried out from February to March 2020 in the Birbhum District of West Bengal, India. Interviews were conducted utilising the retrospective case study method. A total 203 IPs participated who reported seeing at least one confirmed TB patient in six months prior to the study. In that duration, IPs reported interacting with an average of five suspected TB cases, two of which were later confirmed as having TB. Antibiotic use was found to be common among IPs (highest 69% during the first visit); however, they were prescribed before the patient was suspected or confirmed as having TB. We noted the practice of prolonged treatment among IPs as patients were prescribed medicines until the second follow-up visit. Referral was the preferred TB case management approach among IPs, but delayed referral was observed, with only one-third (34%) of patients being referred to higher health facilities during their first visit. This study presents important findings on IPs' TB care practices which have consequences for achieving India's National Goal of TB elimination.

A data compendium associating the genomes of 12,289 Mycobacterium tuberculosis isolates with quantitative resistance phenotypes to 13 antibiotics

The Comprehensive Resistance Prediction for Tuberculosis: an International Consortium (CRyPTIC) presents here a data compendium of 12,289 Mycobacterium tuberculosis global clinical isolates, all of which have undergone whole-genome sequencing and have had their minimum inhibitory concentrations to 13 antitubercular drugs measured in a single assay. It is the largest matched phenotypic and genotypic dataset for M. tuberculosis to date. Here, we provide a summary detailing the breadth of data collected, along with a description of how the isolates were selected, collected, and uniformly processed in CRyPTIC partner laboratories across 23 countries. The compendium contains 6,814 isolates resistant to at least 1 drug, including 2,129 samples that fully satisfy the clinical definitions of rifampicin resistant (RR), multidrug resistant (MDR), pre-extensively drug resistant (pre-XDR), or extensively drug resistant (XDR). The data are enriched for rare resistance-associated variants, and the current limits of genotypic prediction of resistance status (sensitive/resistant) are presented by using a genetic mutation catalogue, along with the presence of suspected resistance-conferring mutations for isolates resistant to the newly introduced drugs bedaquiline, clofazimine, delamanid, and linezolid. Finally, a case study of rifampicin monoresistance demonstrates how this compendium could be used to advance our genetic understanding of rare resistance phenotypes. The data compendium is fully open source and it is hoped that it will facilitate and inspire future research for years to come.

Prescribing practices for presumptive TB among private general practitioners in South Africa: a cross-sectional, standardised patient study

Introduction

Medicine prescribing practices are integral to quality of care for leading infectious diseases such as tuberculosis (TB). We describe prescribing practices in South Africa’s private health sector, where an estimated third of people with TB symptoms first seek care.

Methods

Sixteen standardised patients (SPs) presented one of three cases during unannounced visits to private general practitioners (GPs) in Durban and Cape Town: TB symptoms, HIV-positive; TB symptoms, a positive molecular test for TB, HIV-negative; and TB symptoms, history of incomplete TB treatment, HIV-positive. Prescribing practices were recorded in standardised exit interviews and analysed based on their potential to contribute to negative outcomes, including increased healthcare expenditures, antibiotic overuse or misuse, and TB diagnostic delay. Factors associated with antibiotic use were assessed using Poisson regression with a robust variance estimator.

Results

Between August 2018 and July 2019, 511 SP visits were completed with 212 GPs. In 88.5% (95% CI 85.2% to 91.1%) of visits, at least one medicine (median 3) was dispensed or prescribed and most (93%) were directly dispensed. Antibiotics, which can contribute to TB diagnostic delay, were the most common medicine (76.5%, 95% CI 71.7% to 80.7% of all visits). A majority (86.1%, 95% CI 82.9% to 88.5%) belonged to the WHO Access group; fluoroquinolones made up 8.8% (95% CI 6.3% to 12.3%). Factors associated with antibiotic use included if the SP was asked to follow-up if symptoms persisted (RR 1.14, 95% CI 1.04 to 1.25) and if the SP presented as HIV-positive (RR 1.11, 95% CI 1.01 to 1.23). An injection was offered in 31.9% (95% CI 27.0% to 37.2%) of visits; 92% were unexplained. Most (61.8%, 95% CI 60.2% to 63.3%) medicines were not listed on the South African Primary Healthcare Essential Medicines List.

Conclusion

Prescribing practices among private GPs for persons presenting with TB-like symptoms in South Africa raise concern about inappropriate antimicrobial use, private healthcare costs and TB diagnostic delay.

Fluoroquinolone susceptibility in first-line drug-susceptible M. tuberculosis isolates in Lima, Peru

Objective

To determine at two distinct time points the prevalence of resistance to ofloxacin (OFX), the representative class drug of fluoroquinolones (FQs), in M. tuberculosis isolates susceptible to first-line drugs.

Results

There were 279 M. tuberculosis isolates from the two cohorts (2004–2005: 238 isolates; 2017: 41 isolates) that underwent OFX drug-susceptibility testing (critical concentration: 2 µg/ml). Of 238 isolates in Cohort 1, no resistance to OFX was detected (95% CI 0–0.016); likewise, in Cohort 2, no resistance to OFX was detected in 41 isolates (95% CI 0–0.086). Our findings suggest that FQ use remains a viable option for the treatment of first-line drug-susceptible TB in Peru.

Evidence-based Definition for Extensively Drug-resistant Tuberculosis

RATIONALE

Until 2020, extensively drug-resistant tuberculosis (XDR-TB) was defined as resistance to rifampicin and isoniazid (multidrug-resistant tuberculosis, MDR-TB), any fluoroquinolone (FQ) and any second-line injectable drug (SLID). In 2019 the World Health Organization issued new recommendations for managing patients with drug-resistant tuberculosis, substantially limiting the role of SLID in MDR-TB treatment and thus putting that XDR-TB definition into question.

OBJECTIVE

To propose an up-to-date definition for XDR-TB.

METHODS

We used a large dataset to assess treatment outcomes for MDR-TB patients exposed to any type of longer regimen. We included patients with bacteriologically confirmed MDR-TB and known FQ and SLID resistance results. We did logistic regression to estimate adjusted odds ratios (aORs) for unfavourable treatment outcome (failure, relapse, death, loss-to-follow-up) by resistance pattern (FQ, SLID) and Group A drug use (moxifloxacin/levofloxacin, linezolid, bedaquiline).

MEASUREMENTS AND MAIN RESULTS

We included 11,666 patients with MDR-TB; 4653 (39.9%) had an unfavourable treatment outcome. Resistance to FQs increased the odds of an unfavourable treatment outcome (aOR 1.91; 95% confidence interval [95%CI] 1.63-2.23). Administration of bedaquiline and/or linezolid improved treatment outcomes regardless of resistance to FQ and/or SLID. Among XDR-TB patients, compared to persons receiving no Group A drug, aORs for unfavourable 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 plus additional resistance to FQ plus bedaquiline and/or linezolid, and helps assess the adequacy of this definition for surveillance and treatment choice.NOTE: This article has been updated on July 16, 2021. When it was initially posted on June 9, 2021, the name of one of the coauthors, Dr. Christian Lienhardt, was inadvertently omitted. This version includes Dr. Lienhardt's affilations and contributions; the affiliations have therefore been renumbered.

The Relation Between the Emergence of Fluoroquinolone Resistance and Fluoroquinolone Exposure in New Cases of Active Pulmonary Tuberculosis

OBJECTIVE

This study aimed to determine the ratio of fluoroquinolone (FQ) exposure before the diagnosis of patients with a new case of active pulmonary tuberculosis (TB) and to investigate the correlation of this treatment with the emergence of FQ-resistant strains.

MATERIAL AND METHODS

In this retrospective comparative case series study, a total of 132 patients, who had been diagnosed with adult, culture-positive, active pulmonary TB were reviewed. The FQ group had 30 patients who had had ≥1 time and ≥7 days of FQ exposure within 1 year before the diagnoses. The control group included an equal number of patients with TB with similar demographic characteristics (non-FQ group). Ofloxacin (OFX) and moxifloxacin (MFX) resistance were examined at 2 different concentrations (2 and 4 mg/L for OFX; 0.25 and 0.5 mg/L for MFX).

RESULTS

Of the 132 patients, 30 (22%) had 7 days or longer of FQ monotherapy within 1 year of initiation of anti-TB treatment. FQ resistance was detected in 2 (3.3%) patients. In the FQ group, MFX resistance at 0.25 mg/L concentration was observed in 1 patient, whereas another patient had OFX and MFX resistance at 4 mg/L and 0.5 mg/L concentrations, respectively. In the non-FQ group, no FQ resistance was detected in any of the patients. No statistically significant difference in terms of development of FQ resistance was found between the ratios of FQ and non-FQ groups (p=0.492). Although there was no statistically significant difference, 2 patients, in whom resistance was detected, had FQ exposure before their diagnosis.

CONCLUSION

The FQ exposure ratio before the diagnosis is high (22%) in this cohort that includes patients with new active pulmonary TB, and the presence of patients with FQ resistance (even if only a few) should be a noteworthy and cautionary result in terms of FQ exposure and resistance development.

Diagnosis and treatment of multidrug-resistant tuberculosis

Tuberculosis (TB) is still a major health problem worldwide. Especially, multidrug-resistant TB (MDR-TB), which is defined as TB that shows resistance to both isoniazid and rifampicin, is a barrier in the treatment of TB. Globally, approximately 3.4% of new TB patients and 20% of the patients with a history of previous treatment for TB were diagnosed with MDR-TB. The treatment of MDR-TB requires medications for a long duration (up to 20–24 months) with less effective and toxic second-line drugs and has unfavorable outcomes. However, treatment outcomes are expected to improve due to the introduction of a new agent (bedaquiline), repurposed drugs (linezolid, clofazimine, and cycloserine), and technological advancement in rapid drug sensitivity testing. The World Health Organization (WHO) released a rapid communication in 2018, followed by consolidated guidelines for the treatment of MDR-TB in 2019 based on clinical trials and an individual patient data meta-analysis. In these guidelines, the WHO suggested reclassification of second-line anti-TB drugs and recommended oral treatment regimens that included the new and repurposed agents. The aims of this article are to review the treatment strategies of MDR-TB based on the 2019 WHO guidelines regarding the management of MDR-TB and the diagnostic techniques for detecting resistance, including phenotypic and molecular drug sensitivity tests.

Trend of multidrug and fluoroquinolone resistance in Mycobacterium tuberculosis isolates from 2010 to 2014 in Korea: a multicenter study

BACKGROUND/AIMS

This study was conducted to evaluate the recent prevalence and trend of anti-tuberculosis (TB) drug resistance with a focus on multidrug-resistance (MDR) and fluoroquinolone resistance in South Korea.

METHODS

We retrospectively reviewed the drug susceptibility testing results of culture-confirmed Mycobacterium tuberculosis isolates collected from 2010 to 2014 at seven tertiary hospitals in South Korea.

RESULTS

A total of 5,599 cases were included: 4,927 (88.0%) were new cases and 672 (12.0%) were previously treated cases. The MDR rate has significantly decreased from 6.0% in 2010 to 3.0% in 2014 among new cases, and from 28.6% in 2010 to 18.4% in 2014 among previously treated cases (p < 0.001 and p = 0.027, respectively). The resistance rate to any f luoroquinolone was 0.8% (43/5,221) in non-MDR-TB patients, as compared to 26.2% (99/378) in MDR-TB patients (p < 0.001). There was no significant change in the trend of fluoroquinolone resistance among both nonMDR-TB and MDR-TB patients. Among the 43 non-MDR-TB patients with fluoroquinolone resistance, 38 (88.4%) had fluoroquinolone mono-resistant isolates.

CONCLUSION

The prevalence of MDR-TB has significantly decreased from 2010 to 2014. The prevalence of fluoroquinolone resistance among non-MDR-TB patients was low, but the existence of fluoroquinolone mono-resistant TB may be a warning on the widespread use of fluoroquinolone in the community.

Recommendations and guidelines for the treatment of pneumonia in Taiwan

Pneumonia is a leading cause of death worldwide, ranking third both globally and in Taiwan. This guideline was prepared by the 2017 Guidelines Recommendations for Evidence-based Antimicrobial agents use in Taiwan (GREAT) working group, formed under the auspices of the Infectious Diseases Society of Taiwan (IDST). A consensus meeting was held jointly by the IDST, Taiwan Society of Pulmonary and Critical Care Medicine (TSPCCM), the Medical Foundation in Memory of Dr. Deh-Lin Cheng, the Foundation of Professor Wei-Chuan Hsieh for Infectious Diseases Research and Education and CY Lee's Research Foundation for Pediatric Infectious Diseases and Vaccines. The final guideline was endorsed by the IDST and TSPCCM. The major differences between this guideline and the 2007 version include the following: the use of GRADE methodology for the evaluation of available evidence whenever applicable, the specific inclusion of healthcare-associated pneumonia as a category due to the unique medical system in Taiwan and inclusion of recommendations for treatment of pediatric pneumonia. This guideline includes the epidemiology and recommendations of antimicrobial treatment of community-acquired pneumonia, hospital-acquired pneumonia, ventilator-associated pneumonia, healthcare-associated pneumonia in adults and pediatric pneumonia.

Genetics and roadblocks of drug resistant tuberculosis

Considering the extensive evolutionary history of Mycobacterium tuberculosis, anti-Tuberculosis (TB) drug therapy exerts a recent selective pressure. However, in a microorganism devoid of horizontal gene transfer and with a strictly clonal populational structure such as M. tuberculosis the usual, but not sole, path to overcome drug susceptibility is through de novo mutations on a relatively strict set of genes. The possible allelic diversity that can be associated with drug resistance through several mechanisms such as target alteration or target overexpression, will dictate how these genes can become associated with drug resistance. The success demonstrated by this pathogenic microbe in this latter process and its ability to spread is currently one of the major obstacles to an effective TB elimination. This article reviews the action mechanism of the more important anti-TB drugs, including bedaquiline and delamanid, along with new findings on specific resistance mechanisms. With the development, validation and endorsement of new in vitro molecular tests for drug resistance, knowledge on these resistance mechanisms and microevolutionary dynamics leading to the emergence and fixation of drug resistance mutations within the host is highly important. Additionally, the fitness toll imposed by resistance development is also herein discussed together with known compensatory mechanisms. By elucidating the possible mechanisms that enable one strain to reacquire the original fitness levels, it will be theoretically possible to make more informed decisions and develop novel strategies that can force M. tuberculosis microevolutionary trajectory down through a path of decreasing fitness levels.

Short-course versus long-course therapy of the same antibiotic for community-acquired pneumonia in adolescent and adult outpatients

BACKGROUND

Community-acquired pneumonia (CAP) is a lung infection that can be acquired during day-to-day activities in the community (not while receiving care in a hospital). Community-acquired pneumonia poses a significant public health burden in terms of mortality, morbidity, and costs. Shorter antibiotic courses for CAP may limit treatment costs and adverse effects, but the optimal duration of antibiotic treatment is uncertain.

OBJECTIVES

To evaluate the efficacy and safety of short-course versus longer-course treatment with the same antibiotic at the same daily dosage for CAP in non-hospitalised adolescents and adults (outpatients). We planned to investigate non-inferiority of short-course versus longer-term course treatment for efficacy outcomes, and superiority of short-course treatment for safety outcomes.

SEARCH METHODS

We searched CENTRAL, which contains the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, five other databases, and three trials registers on 28 September 2017 together with conference proceedings, reference checking, and contact with experts and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short- and long-courses of the same antibiotic for CAP in adolescent and adult outpatients.

DATA COLLECTION AND ANALYSIS

We planned to use standard Cochrane methods.

MAIN RESULTS

Our searches identified 5260 records. We did not identify any RCTs that compared short- and longer-courses of the same antibiotic for the treatment of adolescents and adult outpatients with CAP.We excluded two RCTs that compared short courses (five compared to seven days) of the same antibiotic at the same daily dose because they evaluated antibiotics (gemifloxacin and telithromycin) not commonly used in practice for the treatment of CAP. In particular, gemifloxacin is no longer approved for the treatment of mild-to-moderate CAP due to its questionable risk-benefit balance, and reported adverse effects. Moreover, the safety profile of telithromycin is also cause for concern.We found one ongoing study that we will assess for inclusion in future updates of the review.

AUTHORS' CONCLUSIONS

We found no eligible RCTs that studied a short-course of antibiotic compared to a longer-course (with the same antibiotic at the same daily dosage) for CAP in adolescent and adult outpatients. The effects of antibiotic therapy duration for CAP in adolescent and adult outpatients remains unclear.

A study on pattern of resistance to second line anti tubercular drugs among multi drug resistant tuberculosis patients

AIMS AND OBJECTIVES

To determine the prevalence and pattern of resistance to second line drugs among multi drug resistant (MDR) tuberculosis patients being treated on category IV regimen.

METHODOLOGY

This study was conducted at Department of Respiratory Medicine, J.L.N. Medical College, Ajmer in collaboration with IRL, STDC, Ajmer. Second line anti tubercular drug sensitivity for 398 multi drug resistant tuberculosis patients (between June-2015 and June-2016) was done to find out prevalence and pattern of resistance to second line drugs. Second line drug sensitivity was performed at accredited laboratory, Microbiology department, S.M.S. Medical College, Jaipur.

RESULTS

Among these 398 patients, 136 (34.17%) were resistant to fluoroquinolones (Ofloxacin) (Pre XDR); 18 (4.52%) were resistant to one of the aminoglycosides (Inj. Kanamycin, Capreomycin, Amikacin) (Pre XDR); while 22 (5.53%) patients were resistant to fluoroquinolones as well as aminoglycosides (XDR). 148 (37.18%) patients were found sensitive to both the drugs. Samples of 41 (10.3%) patients were contaminated and no growth was seen in 33 (8.29%) patients.

CONCLUSION

Nearly half of the multi drug resistant (MDR) tuberculosis patients (44.22%) being treated on category IV regimen also have resistance to either fluoroquinolones or aminoglycosides or both i.e. Pre XDR or XDR. This may result in poor outcome of category IV regimen under RNTCP. There is a strong need for provision of culture sensitivity for all first line drugs and at least two second line drugs viz. Fluoroquinolones and aminoglycosides for all the patients registered as smear positive under RNTCP. There is also a need for development of rapid culture technique for sensitivity to second line drugs.

An undiagnosed pleural effusion with surprising consequences

We present the case of a 43-year-old Italian woman with a left undiagnosed pleural effusion, which in subsequent months presented a clinically unexpected evolution with the appearance at first of a right wrist tenosynovitis and subsequently a bilateral lung involvement caused by M. Tuberculosis. With this case report, we would like to underline the importance of making a correct diagnosis of any pleural effusion as soon as possible by at least a thoracocentesis. If untreated, tuberculosis may easily disseminate to other organs. Some considerations and suggestions for antibiotic treatment of pleural effusion will also be given, since many antibiotics have some anti-tuberculosis effect and may delay the diagnosis of this infectious disease.

The challenge of the new tuberculosis drugs

Tuberculosis (TB) continues to cause more deaths worldwide than any other single infectious disease. Even though tuberculosis appears to be decreasing in incidence globally for some time, the proportion of drug resistance is increasing, contributing to greater complexity, morbidity and mortality as well as cost. Since the advent of rifampicin in the 1960s, and the implementation of standard quadruple anti-tuberculosis regimen in the late 1970s, no new drugs have been changed the first line regimen. This regimen is effective however it is pill burden, and duration has not received investment and innovation. Drug-resistant regimens are long and frequently poorly tolerated due to significant toxicity. This review is an update on what is new in the treatment of drug-susceptible and drug-resistant tuberculosis, new TB drugs currently being used and studied in clinical trials are also mentioned. Fortunately, there have been many significant advances in this field in recent years. The horizon is changing with the new WHO shorter multidrug-resistant tuberculosis regimens and with the increasing availability of new or repurposed drugs like bedaquiline, delamanid, clofazimine and linezolid. These drugs pose new challenges relating to their rational use to prevent selection of resistant strains of Mycobacterium tuberculosis even before a new regimen has been studied. The availability of these new drugs is offering hope and new possibilities for saving patients who had few or no treatment options. Their use and combination into effective regimens need to be studied; trials are in progress. It is hoped that soon we will be able to treat sensitive and drug-resistant cases with a universal regimen, this would revolutionise treatment and take us another step closer towards elimination.

Perspectives on Advances in Tuberculosis Diagnostics, Drugs, and Vaccines

Despite concerted efforts over the past 2 decades at developing new diagnostics, drugs, and vaccines with expanding pipelines, tuberculosis remains a global emergency. Several novel diagnostic technologies show promise of better point-of-care rapid tests for tuberculosis including nucleic acid-based amplification tests, imaging, and breath analysis of volatile organic compounds. Advances in new and repurposed drugs for use in multidrug-resistant (MDR) or extensively drug-resistant (XDR) tuberculosis have focused on development of several new drug regimens and their evaluation in clinical trials and now influence World Health Organization guidelines. Since the failure of the MVA85A vaccine 2 years ago, there have been no new tuberculosis vaccine candidates entering clinical testing. The current status quo of the lengthy treatment duration and poor treatment outcomes associated with MDR/XDR tuberculosis and with comorbidity of tuberculosis with human immunodeficiency virus and noncommunicable diseases is unacceptable. New innovations and political and funder commitment for early rapid diagnosis, shortening duration of therapy, improving treatment outcomes, and prevention are urgently required.

Moxifloxacin and gatifloxacin for initial therapy of tuberculosis: a meta-analysis of randomized clinical trials

Moxifloxacin (MOX) and gatifloxacin (GAT) have exhibited promising mycobactericidal activity, and a number of clinical trials have been conducted in recent decades to compare the treatment efficacy of MOX-containing and/or GAT-containing regimens with the standard regimen. The aim of this meta-analysis for clinical trials of MOX- or GAT-containing regimens was to evaluate their treatment efficacy and safety in initial therapy for drug-sensitive tuberculosis (TB). Databases were searched for randomized controlled trials, and nine studies with 6980 patients were included. We found that fluoroquinolone substitution for isoniazid or ethambutol in short-course regimens might result in more frequent unfavorable treatment outcomes compared with the standard regimen—in particular, an increased incidence of relapse. In a per-protocol analysis, MOX-containing regimens had slightly higher rates of sputum culture conversion at two months than the standard regimen (RR 1.08, 95% CI 1.04–1.11, P <0.001); there was no significant difference in the rate of sputum conversion between the GAT-containing regimens and the standard regimen (RR 1.13, 95% CI 0.96–1.33, P = 0.13). There were no significant differences in the incidence of death from any cause, including TB, nor were there serious adverse events between the MOX- or GAT-containing regimens and the standard regimen. In conclusion, MOX or GAT might not have the ability to shorten treatment duration in the initial therapy for tuberculosis despite the non-inferiority or even slightly better efficacy in the early phase of treatment compared with the standard regimen. Furthermore, it is safe to include MOX or GAT in initial TB treatment.

Why healthcare workers are sick of TB

Dr Thato Mosidi never expected to be diagnosed with tuberculosis (TB), despite widely prevalent exposure and very limited infection control measures. The life-threatening diagnosis of primary extensively drug-resistant TB (XDR-TB) came as an even greater shock. The inconvenient truth is that, rather than being protected, Dr Mosidi and thousands of her healthcare colleagues are at an increased risk of TB and especially drug-resistant TB. In this viewpoint paper we debunk the widely held false belief that healthcare workers are somehow immune to TB disease (TB-proof) and explore some of the key factors contributing to the pervasive stigmatization and subsequent non-disclosure of occupational TB. Our front-line workers are some of the first to suffer the consequences of a progressively more resistant and fatal TB epidemic, and urgent interventions are needed to ensure the safety and continued availability of these precious healthcare resources. These include the rapid development and scale-up of improved diagnostic and treatment options, strengthened infection control measures, and focused interventions to tackle stigma and discrimination in all its forms. We call our colleagues to action to protect themselves and those they care for.

Fluoroquinolone-resistant tuberculosis: implications in settings with weak healthcare systems

Fluoroquinolones (FQ) play an essential role in the treatment and control of multidrug-resistant tuberculosis (MDR-TB). They are also being evaluated as part of newer regimens under development for drug-sensitive TB. As newer FQ-based regimens are explored, knowledge of FQ resistance data from high TB burden countries becomes essential. We examine available FQ resistance data from high TB burden countries and demonstrate the need for comprehensive surveys to evaluate FQ resistance in these countries. The factors driving FQ resistance in such conditions and the cost of such resistance to weak healthcare systems are discussed. The need for a comprehensive policy for addressing the issue of FQ resistance is highlighted.

Replacement of cardiotoxic aminopiperidine linker with piperazine moiety reduces cardiotoxicity? Mycobacterium tuberculosis novel bacterial topoisomerase inhibitors

Recently numerous non-fluoroquinolone-based bacterial type II topoisomerase inhibitors from both the GyrA and GyrB classes have been reported as antibacterial agents. Inhibitors of the GyrA class include aminopiperidine-based novel bacterial type II topoisomerase inhibitors (NBTIs). However, inhibition of the cardiac ion channel remains a serious liability for the aminopiperidine based NBTIs. In this paper we replaced central aminopiperidine linker with piperazine moiety and tested for its biological activity. We developed a series of twenty four compounds with a piperazine linker 1-(2-(piperazin-1-yl)ethyl)-1,5-naphthyridin-2(1H)-one, by following a multistep protocol. Among them compound 4-(2-(7-methoxy-2-oxo-1,5-naphthyridin-1(2H)-yl)ethyl)-N-(4-nitrophenyl)piperazine-1-carboxamide (11) was the most promising inhibitor with Mycobacterium tuberculosis (MTB) DNA gyrase enzyme supercoiling IC50 of 0.29±0.22μM, with a good MTB MIC of 3.45μM. These kind of compounds retains good potency and showed reduced cardiotoxicity compared to aminopiperidines.

Resistance patterns, prevalence, and predictors of fluoroquinolones resistance in multidrug resistant tuberculosis patients

Background

Fluoroquinolones are the backbone of multidrug resistant tuberculosis treatment regimens. Despite the high burden of multidrug resistant tuberculosis in the country, little is known about drug resistance patterns, prevalence, and predictors of fluoroquinolones resistance among multidrug resistant tuberculosis patients from Pakistan.

Objective

To evaluate drug resistance patterns, prevalence, and predictors of fluoroquinolones resistance in multidrug resistant tuberculosis patients.

Methods

This was a cross-sectional study conducted at a programmatic management unit of drug resistant tuberculosis, Lady Reading Hospital Peshawar, Pakistan. Two hundred and forty-three newly diagnosed multidrug resistant tuberculosis patients consecutively enrolled for treatment at study site from January 1, 2012 to July 28, 2013 were included in the study. A standardized data collection form was used to collect patients’ socio-demographic, microbiological, and clinical data. SPSS 16 was used for data analysis.

Results

High degree of drug resistance (median 5 drugs, range 2–8) was observed. High proportion of patients was resistant to all five first-line anti-tuberculosis drugs (62.6%), and more than half were resistant to second line drugs (55.1%). The majority of the patients were ofloxacin resistant (52.7%). Upon multivariate analysis previous tuberculosis treatment at private (OR = 1.953, p = 0.034) and public private mix (OR = 2.824, p = 0.046) sectors were predictors of ofloxacin resistance.

Conclusion

The high degree of drug resistance observed, particularly to fluoroquinolones, is alarming. We recommend the adoption of more restrictive policies to control non-prescription sale of fluoroquinolones, its rational use by physicians, and training doctors in both private and public–private mix sectors to prevent further increase in fluoroquinolones resistant Mycobacterium tuberculosis strains.

Design and synthesis of novel quinoline-aminopiperidine hybrid analogues as Mycobacterium tuberculosis DNA gyraseB inhibitors

Antibiotics with good therapeutic value and novel mechanism of action are becoming increasingly important in today's battle against bacterial resistance. One of the popular targets being DNA gyrase, is currently becoming well-established and clinically validated for the development of novel antibacterials. In the present work, a series of forty eight quinoline-aminopiperidine based urea and thiourea derivatives were synthesized as pharmacophoric hybrids and evaluated for their biological activity. Compound, 1-(4-chlorophenyl)-3-(1-(6-methoxy-2-methylquinolin-4-yl)piperidin-4-yl)thiourea (45) was found to exhibit promising in vitro Mycobacterium smegmatis GyrB IC₅₀ of 0.95 ± 0.12 μM and a well correlated Mycobacterium tuberculosis (MTB) DNA gyrase supercoiling IC₅₀ of 0.62 ± 0.16 μM. Further, compound 45 also exhibited commendable MTB MIC, safe eukaryotic cytotoxic profile with no signs of cardiotoxicity in zebrafish ether-a-go-go-related gene (zERG).

Tuberculosis: clinical trials and new drug regimens

PURPOSE OF REVIEW

Recent advances in the development of new drugs and regimens provide hope that well tolerated, effective, and shorter-duration treatments for tuberculosis (TB) will become available. This review covers the recent trials of new TB drugs and regimens.

RECENT FINDINGS

Moxifloxacin and levofloxacin have equally good efficacy and safety in the early phase of treatment of multidrug-resistant TB (MDR-TB), and linezolid has the potential to cure refractory cases of MDR-TB. Bedaquiline and delamanid may be the best drug candidates for enhancing treatment options for MDR-TB. New chemicals, such as sutezolid, AZD5847, PA-824, SQ109, and BTZ043, show potent activity against Mycobacterium tuberculosis. Late-generation fluoroquinolones in combination with the first-line and second-line anti-TB drugs have been used to shorten the treatment duration in drug-susceptible and MDR-TB.

SUMMARY

New drugs and new combination regimens in clinical trials are expected to increase therapeutic efficacy and shorten treatment duration in both drug-susceptible and drug-resistant TB.

Fluoroquinolone resistance in non-multidrug-resistant tuberculosis-a surveillance study in New South Wales, Australia, and a review of global resistance rates

BACKGROUND

Fluoroquinolones (FQs) are used for drug-susceptible tuberculosis (TB) in patients unable to tolerate first-line agents. Current trials are also investigating these drugs in empiric first-line TB therapy, to improve outcomes and allow for shortened treatment regimens. Widespread FQ use in the community has resulted in FQ resistance in many microorganisms, including Mycobacterium tuberculosis. Despite this, FQ drug susceptibility testing (DST) is rarely performed in non-multidrug-resistant TB (non-MDR-TB).

METHODS

We conducted a 1-year surveillance study of FQ resistance on all MTB isolates from New South Wales (NSW), Australia. In addition, we performed a literature review of previous studies assessing FQ resistance in non-MDR-TB to summarize the global extent of this resistance pattern.

RESULTS

Two (0.6%) out of 357 MTB isolates from NSW were found to be FQ-resistant. One isolate was an MDR strain (11% of all MDR-TB). The other was isoniazid-monoresistant (0.3% of all non-MDR-TB). Eleven studies from 10 countries had performed FQ resistance surveillance on non-MDR-TB. In the majority of these studies, FQ resistance was found to be low (mean 1%; 95% confidence interval 0.2-2%).

CONCLUSIONS

FQ resistance in non-MDR-TB is uncommon in NSW, Australia. The existing global evidence suggests that FQ resistance remains largely confined to MDR-TB strains. In the majority of TB endemic regions, however, FQ resistance in non-MDR-TB has not been assessed. Knowledge of the prevalence of FQ resistance in MTB is essential to guide the rational use of these drugs, including their feasibility as first-line agents.

Community-acquired pneumonia and tuberculosis: differential diagnosis and the use of fluoroquinolones

The respiratory fluoroquinolones moxifloxacin, gemifloxacin, and high-dose levofloxacin are recommended in guidelines for effective empirical antimicrobial therapy of community-acquired pneumonia (CAP). The use of these antibiotics for this indication in areas with a high prevalence of tuberculosis (TB) has been questioned due to the perception that they contribute both to delays in the diagnosis of pulmonary TB and to the emergence of fluoroquinolone-resistant strains of Mycobacterium tuberculosis. In this review, we consider some of the important questions regarding the potential use of fluoroquinolones for the treatment of CAP where the burden of TB is high. The evidence suggests that the use of fluoroquinolones as recommended for 5-10 days as empirical treatment for CAP, according to current clinical management guidelines, is appropriate even in TB-endemic regions. It is critical to quickly exclude M. tuberculosis as a cause of CAP using the most rapid relevant diagnostic investigations in the management of all patients with CAP.

Drug-resistant tuberculosis

PURPOSE OF REVIEW

This review discusses the recent evidence on epidemiology, diagnosis, and treatment of drug-resistant and multidrug-resistant (MDR) tuberculosis (TB), an area where solutions for better diagnosis and treatment continually develop.

RECENT FINDINGS

The prevalence of drug resistance has been constantly rising during the recent years. It has peaked in eastern European countries such as Belarus, where a record of 35.5% MDR-TB amongst new cases have been reported from Minsk. New diagnostic tools are becoming available. Xpert MTB/RIF is by far the most promising of these new techniques. Clinical management of drug-resistant TB is still cumbersome. However, after over 40 years of neglect, new drugs are becoming readily available: delamanid, bedaquiline, and PA-824 combined into innovative regimens raise hopes for substantially higher success rates.

SUMMARY

The innovative diagnostic tools recently validated are changing the traditional paradigms of TB diagnosis, for too long based on sputum smear, culture, and drug susceptibility testing. New anti-TB compounds, which can be combined with several 'old' drugs with new indications, are gradually modifying the chances of cure for MDR-TB cases. Although initial evidence appears promising, the market use of new drugs must be accompanied by a serious public health approach aimed at preventing the development of further drug resistance.