Role of therapeutic drug monitoring in the treatment of multi-drug resistant tuberculosis

Tuberculosis (TB) is a leading cause of mortality worldwide, and resistance to anti-tuberculosis drugs is a challenge to effective treatment. Multi-drug resistant TB (MDR-TB) can be difficult to treat, requiring long durations of therapy and the use of second line drugs, increasing a patient's risk for toxicities and treatment failure. Given the challenges treating MDR-TB, clinicians can improve the likelihood of successful outcomes by utilizing therapeutic drug monitoring (TDM). TDM is a clinical technique that utilizes measured drug concentrations from the patient to adjust therapy, increasing likelihood of therapeutic drug concentrations while minimizing the risk of toxic drug concentrations. This review paper provides an overview of the TDM process, pharmacokinetic parameters for MDR-TB drugs, and recommendations for dose adjustments following TDM.

Diagnosing osteoarticular tuberculosis and detecting rifampicin resistance: A comparative analysis of Truenat MTB Plus vs GeneXpert Ultra

SETTING

Diagnosing osteoarticular tuberculosis (OATB) and detecting drug resistance is a challenge in an endemic country like India.

OBJECTIVE

Truenat MTB Plus assay (TruPlus), a chip-based portable machine, was compared with GeneXpert Ultra (GxUltra) for diagnosing drug-resistant OATB.

DESIGN

115 synovial fluid and pus specimens [22 culture-positive confirmed, 58 culture-negative clinically-suspected, 35 non-TB controls] processed between 2017 and 2023 were subjected to TruPlus, GxUltra and multiplex-PCR for diagnosing OATB. They were further screened for rifampicin resistance using TruRif chip. The performance was evaluated against composite reference standard, phenotypic drug susceptibility testing and rpoB gene sequencing.

RESULTS

TruPlus, GxUltra and MPCR detected 77.5 %, 71.25 %, and 83.75 %, cases of OATB, respectively. TruPlus detected five additional cases missed by GxUltra. The performance of TruPlus was comparable to GxUltra (p = 0.074) and to MPCR (p = 0.074), while performance of GxUltra was significantly inferior to MPCR (p = 0.004). The overall agreement with reference standard was substantial for TruPlus and MPCR and moderate for GxUltra. Both TruRif and GxUltra reported 4 cases as rifampicin resistant.

CONCLUSION

TruPlus along with TruRif offers better sensitivity than GxUltra. Its compact and portable platform allows wider application in peripheral settings, thus making it a pragmatic solution for diagnosing OATB and its drug resistance.

Whole genome sequencing of drug-resistant Mycobacterium tuberculosis isolates in Victoria, Australia

OBJECTIVES

Whole genome sequencing (WGS) can identify clusters, transmission patterns, and drug resistance mutations. This is important in low-burden settings such as Australia, as it can assist in efficient contact tracing and surveillance.

METHODS

We conducted a retrospective cohort study using WGS from 155 genomically defined drug-resistant Mycobacterium tuberculosis (DR-TB) isolates collected between 2018-2021 in Victoria, Australia. Bioinformatic analysis was performed to identify resistance-conferring mutations, lineages, clusters and understand how local sequences compared with international context.

RESULTS

Of the 155 sequences, 42% were identified as lineage 2 and 35% as lineage 1; 65.8% (102/155) were isoniazid mono-resistant, 8.4% were multi-drug resistant TB and 5.8% were pre-extensively drug-resistant / extensively drug-resistant TB. The most common mutations were observed in katG and fabG1 genes, especially at Ser315Thr and fabG1 -15 C>T for first-line drugs. Ser450Leu was the most frequent mutation in rpoB gene. Phylogenetic analysis confirmed that Victorian DR-TB were associated with importation events. There was little evidence of local transmission with only five isolate pairs.

CONCLUSION

Isoniazid-resistant TB is the commonest DR-TB in Victoria, and the mutation profile is similar to global circulating DR-TB. Most cases are diagnosed among migrants with limited transmission. This study highlights the value of WGS in identification of clusters and resistance-conferring mutations. This information is crucial in supporting disease mitigation and treatment strategies.

Low serum vitamin D in North Indian multi-drug resistant pulmonary tuberculosis patients: the role of diet and sunlight

Background: Tuberculosis (TB) and malnutrition are major global health problems, with multidrug-resistant (MDR) TB complicating international efforts. The role of vitamin D in susceptibility to and as an adjunctive treatment for TB is being studied extensively, although no study has included MDR-TB patients in context to dietary profile with vitamin D levels and sunlight exposure.Objective: This study aimed to estimate vitamin D serum levels and examine their association with dietary intake of vitamin D and sun exposure in patients with MDR-TB.Methods: North Indian participants were enrolled in three groups: MDR-TB, drug-susceptible pulmonary TB (DS-PTB), and healthy controls. All consenting participants underwent the estimation of macro- and micronutrient intake and sunlight exposure using structured questionnaires. Serum biochemistry, including 25-hydroxyvitamin D and calcium levels, was measured, and the correlation between variables was determined.Results: 747 participants were enrolled. Significant differences among the three groups were found in mean serum 25-hydroxyvitamin D levels, body mass index, macronutrient intake, dietary vitamin D and calcium content, and sun exposure index (SEI). All except sun exposure (SEI was highest in DS-PTB patients) were found to follow the trend: MDR-TB < DS-PTB < healthy controls. The mean serum vitamin D levels of all groups were deficient and correlated positively with dietary intake and SEI.Conclusion: In this study's we found significant association of serum vitamin D concentrations, dietary intake and sunlight exposure in MDR-TB, DS-PTB patients and healthy controls. Dietary intake may be more important than sun exposure in determining serum levels. However, the significance of this finding is uncertain. Further studies are required to confirm the association, direction, and potential for vitamin D supplementation to treat or prevent MDR-TB infection.

Isoniazid resistance-conferring mutations are associated with highly variable phenotypic resistance

Background

High-dose isoniazid is recommended in the 9-12 months short-course regimen for multidrug-resistant tuberculosis with inhA mutation. However, there is insufficient evidence to support the assumption of genotypic-phenotypic concordance. This study aimed to identify the genetic mutations associated with high-level phenotypic isoniazid resistance.

Methods

Clinical isolates from patients with drug-resistant tuberculosis were profiled by whole-genome sequencing and subjected to minimum inhibitory concentration (MIC) testing using MGIT based-method. MICs were performed in concentration ranges based on the mutation present: isolates with no isoniazid resistance-conferring mutations and H37Rv, 0.016-0.256 µg/ml; inhA, 0.256-4.0 µg/ml, katG 1.0-16.0 µg/ml; and inhA + katG, 4.0-64.0 µg/ml. Isolates demonstrating resistance at the upper limit of the concentration range were tested up to the maximum of 64.0 µg/ml. Bootstrap of the mean MICs was performed to increase the robustness of the estimates and an overlap index was used to compare the distributions of the MICs for each mutation profile.

Results

A total of 52 clinical isolates were included in this analysis. Bootstrap MIC means for inhA, katG and inhA + katG were 33.64 (95% CI, 9.47, 56.90), 6.79 (4.45, 9.70) and 52.34 (42.750, 61.66) µg/ml, respectively. There was high overlap between inhA and inhA + katG mutations (eta = 0.45) but not with inhA and katG (eta = 0.19). Furthermore, katG showed poor overlap with inhA + katG mutations (eta = 0.09). Unexpectedly, 4/8 (50.0%) of all InhA mutants demonstrated high-level resistance, while 20/24 (83.3%) of katG mutants demonstrated moderate-level resistance.

Conclusions

InhA mutations demonstrated unexpectedly high MICs and showed high overlap with inhA + katG. Contrary to the common belief that katG mutants are associated with high-level resistance, this mutation primarily showed moderate-level resistance.

Nanomotion technology in combination with machine learning: a new approach for a rapid antibiotic susceptibility test for Mycobacterium tuberculosis

Nanomotion technology is a growth-independent approach that can be used to detect and record the vibrations of bacteria attached to cantilevers. We have developed a nanomotion-based antibiotic susceptibility test (AST) protocol for Mycobacterium tuberculosis (MTB). The protocol was used to predict strain phenotype towards isoniazid (INH) and rifampicin (RIF) using a leave-one-out cross-validation (LOOCV) and machine learning techniques. This MTB-nanomotion protocol takes 21 h, including cell suspension preparation, optimized bacterial attachment to functionalized cantilever, and nanomotion recording before and after antibiotic exposure. We applied this protocol to MTB isolates (n = 40) and were able to discriminate between susceptible and resistant strains for INH and RIF with a maximum sensitivity of 97.4% and 100%, respectively, and a maximum specificity of 100% for both antibiotics when considering each nanomotion recording to be a distinct experiment. Grouping recordings as triplicates based on source isolate improved sensitivity and specificity to 100% for both antibiotics. Nanomotion technology can potentially reduce time-to-result significantly compared to the days and weeks currently needed for current phenotypic ASTs for MTB. It can further be extended to other anti-TB drugs to help guide more effective TB treatment.

Molecular investigations of Mycobacterium tuberculosis genotypes among baseline and follow-up strains circulating in four regions of Eswatini

BACKGROUND

The tuberculosis (TB) epidemic remains a major global health problem and Eswatini is not excluded. Our study investigated the circulating genotypes in Eswatini and compared them at baseline (start of treatment) and follow-up during TB treatment.

METHODS

Three hundred and ninety (n = 390) participants were prospectively enrolled from referral clinics and patients who met the inclusion criteria, were included in the study. A total of 103 participants provided specimens at baseline and follow-up within six months. Mycobacterium tuberculosis (M.tb) strains were detected by GeneXpert® MTB/RIF assay (Cephied, USA) and Ziehl -Neelsen (ZN) microscopy respectively at baseline and follow-up time-points respectively. The 206 collected specimens were decontaminated and cultured on BACTEC™ MGIT™ 960 Mycobacteria Culture System (Becton Dickinson, USA). Drug sensitivity testing was performed at both baseline and follow-up time points. Spoligotyping was performed on both baseline and follow-up strains after DNA extraction.

RESULTS

Resistance to at least one first line drug was detected higher at baseline compared to follow-up specimens with most of them developing into multidrug-resistant (MDR)-TB. A total of four lineages and twenty genotypes were detected. The distribution of the lineages varied among the different regions in Eswatini. The Euro-American lineage was the most prevalent with 46.12% (95/206) followed by the East Asian with 24.27% (50/206); Indo-Oceanic at 9.71% (20/206) and Central Asian at 1.94% (4/206). Furthermore, a high proportion of the Beijing genotype at 24.27% (50/206) and S genotype at 16.50% (34/206) were detected. The Beijing genotype was predominant in follow-up specimens collected from the Manzini region with 48.9% (23/47) (p = 0.001). A significant proportion of follow-up specimens developed MDR-TB (p = 0.001) with Beijing being the major genotype in most follow-up specimens (p < 0.000).

CONCLUSION

Eswatini has a high M.tb genotypic diversity. A significant proportion of the TB infected participants had the Beijing genotype associated with MDR-TB in follow-up specimens and thus indicate community wide transmission.

Surveillance of multidrug-resistant tuberculosis in sub-Saharan Africa through wastewater-based epidemiology

The spread of multidrug-resistant tuberculosis (MDR-TB) is a serious public health issue, particularly in developing nations. The current methods of monitoring drug-resistant TB (DR-TB) using clinical diagnoses and hospital records are insufficient due to limited healthcare access and underreporting. This study proposes using Wastewater-Based Epidemiology (WBE) to monitor DR-TB in six African countries (Ghana, Nigeria, Kenya, Uganda, Cameroon, and South Africa) and examines the impact of treated wastewater on the spread of TB drug-resistant genes in the environment. Using droplet-digital polymerase chain reaction (ddPCR), the study evaluated untreated and treated wastewater samples in selected African countries for TB surveillance. There was a statistically significant difference in concentrations of genes conferring resistance to TB drugs in wastewater samples from the selected countries (p-value<0.05); South African samples exhibited the highest concentrations of 4.3(±2,77), 4.8(±2.96), 4.4(±3,10) and 4.7(±3,39) log copies/ml for genes conferring resistance to first-line TB drugs (katG, rpoB, embB and pncA respectively) in untreated wastewater. This may be attributed to the higher prevalence of TB/MDR-TB in SA compared to other African countries. Interestingly, genes conferring resistance to second-line TB drugs such as delamanid (ddn gene) and bedaquiline (atpE gene) were detected in relatively high concentrations (4.8(±3,67 and 3.2(±2,31 log copies/ml for ddn and atpE respectively) in countries, such as Cameroon, where these drugs are not part of the MDR-TB treatment regimens, perhaps due to migration or the unapproved use of these drugs in the country. The gene encoding resistance to streptomycin (rrs gene) was abundant in all countries, perhaps due to the common use of this antibiotic for infections other than TB. These results highlight the need for additional surveillance and monitoring, such as WBE, to gather data at a community level. Combining WBE with the One Health strategy and current TB surveillance systems can help prevent the spread of DR-TB in populations.

Case Report: Subfertility and Pregnancy Loss due to Genital Tuberculosis

Tuberculosis (TB) is a disease that primarily affects low and middle income countries (LMICs) but is becoming more relevant in Western countries due to increasing migration from high TB burden countries. It is especially difficult to detect in women with fertility issues as it mimics other more common causes. Delayed diagnosis of TB can result in fallopian tube and endometrial pathology leading to subfertility and pregnancy loss. This case report describes a 34-year-old woman from Ivory Coast who was diagnosed with intrauterine tuberculosis after hysteroscopic evacuation of suspected retained placental tissue following an immature delivery. The patient had a complicated fertility history, including pelvic inflammatory disease and IVF/ICSI procedures, before becoming pregnant at the age of 38. She delivered prematurely at 22 weeks with a retained placenta. A diagnosis of TB was confirmed after pathology revealed granulomatous inflammation, without signs of placental tissue, and further testing confirmed rifampicin-resistant TB. The patient underwent a 15-month course of multi-drug-resistant TB treatment, which postponed her pregnancy wish. The case highlights the challenge of diagnosing genital TB in the female genital tract during subfertility investigations and after a complicated pregnancy in a woman without a history of or symptoms of TB. It underscores the importance of considering TB in the differential diagnosis of subfertility. Screening should be considered in women originating from high endemic countries with unexplained fertility loss and during first trimester screening.

High rates of culture conversion and low loss to follow-up in MDR-TB patients managed at Regional Referral Hospitals in Uganda

BACKGROUND

Multi-drug resistant-tuberculosis (MDR-TB) is an emerging public health concern in Uganda. Prior to 2013, MDR-TB treatment in Uganda was only provided at the national referral hospital and two private-not-for profit clinics. From 2013, it was scaled up to seven regional referral hospitals (RRH). The aim of this study was to measure interim (6 months) treatment outcomes among the first cohort of patients started on MDR-TB treatment at the RRH in Uganda.

METHODS

This was a cross-sectional study in which a descriptive analysis of data collected retrospectively on a cohort of 69 patients started on MDR-TB treatment at six of the seven RRH between 1st April 2013 and 30th June 2014 and had been on treatment for at least 9 months was conducted.

RESULTS

Of the 69 patients, 21 (30.4%) were female, 39 (56.5%) HIV-negative, 30 (43.5%) resistant to both isoniazid and rifampicin and 57 (82.6%) category 1 or 2 drug susceptible TB treatment failures. Median age at start of treatment was 35 years (Interquartile range (IQR): 27-45), median time-to-treatment initiation was 27.5 (IQR: 6-89) days and of the 30 HIV-positive patients, 27 (90.0%) were on anti-retroviral treatment with a median CD4 count of 206 cells/microliter of blood (IQR: 113-364.5). Within 6 months of treatment, 59 (85.5%) patients culture converted, of which 45 (65.2%) converted by the second month and the other 14 (20.3%) by the sixth month; one (1.5%) did not culture convert; three (4.4%) died; and six (8.8%) were lost-to-follow up. Fifty (76.8%) patients experienced at least one drug adverse event, while 40 (67.8%) gained weight. Mean weight gained was 4.7 (standard deviation: 3.2) kilograms.

CONCLUSIONS

Despite MDR-TB treatment initiation delays, most patients had favourable interim treatment outcomes with majority culture converting early and very few getting lost to follow-up. These encouraging interim outcomes indicate the potential for success of a scale-up of MDR-TB treatment to RRH.

The role of bacteriological monitoring using culture and drug susceptibility tests (CDST) on treatment outcomes among MDR/RR-TB patients on treatment: a cohort analysis of patients enrolled on treatment 2010-2015 in Zimbabwe

Introduction

an estimated 25% of the world population is infected with Mycobacterium tuberculosis. In 2017, new tuberculosis cases were estimated at 10 million, while 1.6 million tuberculosis related deaths were recorded, 25% residing in Africa. Treatment outcomes of multi drug resistant Tuberculosis patients in Zimbabwe has been well documented but the role of bacteriological monitoring on treatment outcomes has not been systematically evaluated. The objective of the study was to determine the role of bacteriological monitoring using culture and drug susceptibility tests on treatment outcomes among patients with multi drug resistant tuberculosis.

Methods

a retrospective, secondary data analysis was conducted using routinely collected data of patients with multi drug resistant TB in Zimbabwe. Frequencies were used to summarize categorical variables and a generalized linear model with a log-link function and a Poisson distribution was used to assess factors associated with unfavourable outcomes. The level of significance was set at P-Value<0.05.

Results

about the study collected data from 473 records of patients with an average age of 36.35 years. Forty-nine percent (49%) were male and 51% were female. Results showed that when a patient has baseline culture result missing, has no culture conversion result, regardless of having a follow up culture and drug susceptibility test result, the risk of developing unfavourable outcomes increase by 3.9 times compared to a patient who has received all the three (3) bacteriological monitoring tests.

Conclusion

results highlights the need for consistent bacteriological monitoring of patients to avert unfavourable treatment outcomes.

Deciphering the mechanism of action of antitubercular compounds with metabolomics

Tuberculosis (TB), one of the oldest and deadliest bacterial diseases, continues to cause serious global economic, health, and social problems. Current TB treatments are lengthy, expensive, and routinely ineffective against emerging drug resistant strains. Thus, there is an urgent need for the identification and development of novel TB drugs possessing comprehensive and specific mechanisms of action (MoAs). Metabolomics is a valuable approach to elucidating the MoA, toxicity, and potency of promising chemical leads, which is a critical step of the drug discovery process. Recent advances in metabolomics methodologies for deciphering MoAs include high-throughput screening techniques, the integration of multiple omics methods, mass spectrometry imaging, and software for automated analysis. This review describes recently introduced metabolomics methodologies and techniques for drug discovery, highlighting specific applications to the discovery of new antitubercular drugs and the elucidation of their MoAs.

Application of KTH-integrated nursing model in care of patients with multi-drug resistant tuberculosis

OBJECTIVE

To evaluate the effect of the KTH-integrated nursing model of the knowledge-attitude-belief-practice model (KABP)-transtheoretical model (TTM)-as a health belief model (HBM) in nursing care of patients with multi-drug resistant tuberculosis (MDR-TB).

METHODS

Using a prospective study method, 102 patients with MDR-TB were randomly divided into two groups according to a random number table. The control group (n=51) received conventional nursing care, and the study group (n=51) received a KTH-integrated nursing model. The sputum negative conversion rate, effective rate of lesion absorption, level of disease cognition, compliance, self-efficacy (general self-efficacy scale, GSES score), healthy behavior (health-promoting lifestyle profile, HPLP), and quality of life (GQOL-74 scale score) were compared between the two groups.

RESULTS

Six months after enrollment, the sputum-negative conversion rate, total effective rate of lesion absorption, and total compliance rate of the study group were significantly higher than those of the control group (80.39% vs. 62.75%, 84.31% vs. 66.67%, 96.08% vs. 78.43%, P<0.05). 6 months after enrollment, the treatment plan, etiopathogenesis and harm, precautions, importance of treatment compliance, observation and follow-up, and total score of the study were all significantly higher than those of the control group (P<0.05). Six months after enrollment, the scores of GSES, HPLP and GQOL-74 in the study group were significantly higher than those of the control group (P<0.05).

CONCLUSION

The implementation of a KTH integrated nursing model for patients with MDR-TB was beneficial to promote sputum-negative conversion and lesion absorption, and improved disease awareness, medication compliance, self-efficacy, healthy behavior, and quality of life.

Value of routine whole genome sequencing for Mycobacterium tuberculosis drug resistance detection

Routine whole genome sequencing (WGS) of pathogens is becoming more feasible as sequencing costs decrease and access to benchtop sequencing equipment and bioinformatics pipelines increases. This study examined the added value gained from implementing routine WGS of all Mycobacterium tuberculosis isolates in New South Wales, Australia. Drug resistance markers inferred from WGS data were compared to commercial genotypic drug susceptibility testing (DST) assays and conventional phenotypic DST in all isolates sequenced between 2016 and 2019. Of the 1107 clinical M. tuberculosis isolates sequenced, 29 (2.6%) were multi-drug resistant (MDR); most belonged to Beijing (336; 30.4%) or East-African Indian (332; 30%) lineages. Compared with conventional phenotypic DST, WGS identified an additional 1% of isolates which were likely drug resistant, explained by mutations previously associated with treatment failure and mixed bacterial populations. However, WGS provided a 20% increase in drug resistance detection in comparison with commercial genotypic assays by identifying mutations outside of the classic resistance determining regions in rpoB, inhA, katG, pncA and embB genes. Gains in drug resistance detection were significant (p = 0.0137, paired t-test), but varied substantially for different phylogenetic lineages. In low incidence settings, routine WGS of M. tuberculosis provides better guidance for person-centered management of drug resistant tuberculosis than commercial genotypic assays.

Multi-drug resistant tuberculosis, ten years later

Drug-resistant tuberculosis, especially those with resistance to rifampicin (RR-TB), has become one of the main obstacles to achieving the dream of eradicating tuberculosis. Furthermore, it is necessary to combine three or four different drugs in the attempt to cure TB, however, unfortunately, there are few available that can be considered genuinely effective. Fortunately, the notable worldwide increase in RR-TB in recent years has led to the investment of resources in the development of new drugs for TB, and other drugs investigated for other diseases have been successfully tested on TB. This has resulted in a clear change in the clinical management of these patients over the last 3-4 years, and it is now easier to design therapeutic regimens and achieve higher success rates. All these changes are updated in this review.

Poor treatment outcome and its predictors among drug-resistant tuberculosis patients in Ethiopia: A systematic review and meta-analysis

OBJECTIVE

To assess poor treatment outcomes and their predictors among drug-resistant tuberculosis patients treated in Ethiopia.

METHODS

Data were searched from both electronic databases and other sources. From the whole search, 404 articles were reviewed and 17 articles that fulfilled the inclusion criteria were included in the analysis. Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was followed and Joanna Briggs Institute Critical Appraisal checklist was used for assessing the quality. Risk of bias was assessed using forest plot and Egger's regression test. Data were analyzed using STATA version 15 and Review Manager Software version 5.3.

RESULTS

The overall pooled proportion of poor treatment outcome and mortality was 17.86% and 15.13% respectively. The incidence density rate of poor treatment outcome and mortality was 10.41/1000 person-months and 9.28/1000 person-months respectively. Survival status and successful treatment outcomes were 76.97% and 63.82% respectively. HIV positivity, non-HIV comorbidities, clinical complications, extrapulmonary involvement, undernutrition, anemia, treatment delay, lower body weight, and older age were the predictors of poor treatment outcome.

CONCLUSION

Better survival and treatment success rates were noted in Ethiopia as compared to the global average. The majority of the poor treatment outcomes occurred within the intensive phase. Early initiation of anti-tuberculosis treatment would be important for successful treatment outcomes.

Development of a Carrier-Free Dry Powder Ofloxacin Formulation With Enhanced Aerosolization Properties

Tuberculosis (TB) is a serious infectious disease that affects more than new 10 million patients each year. Many of these cases are resistant to first-line drugs so second-line ones, like fluoroquinolones, need to be incorporated into the therapeutic. Ofloxacin (OF) is a fluoroquinolone which demonstrates high antibiotic activity against the bacteria that causes TB (M. tuberculosis). In this work, ionic complexes, composed by hyaluronic acid (HA) and OF, with different neutralization degrees, were prepared and processed by spray drying (SD) to obtain powders for inhalatory administration. Combining a formulation with high neutralization degree, high SD atomization air flowrate and the use of a high-performance collection cyclone, very good process yields were obtained. Carrier-free formulations with a loading of 0.39-0.46 g_OF/g_powder showed excellent emitted, fine particle, and respirable fractions for capsule loadings of 25 and 100 mg. The ionic complexes demonstrated higher mucoadhesion than pure OF and HA. The best formulation did not affect CALU-3 cell viability up to a dose 6.5 times higher than the MIC₉₀ reported to treat multi-drug resistant TB.

The impact of medical interventions for reducing ototoxicity during treatment for multi-drug resistant tuberculosis

INTRODUCTION

The impact of medical interventions for reducing ototoxicity requires focus in contexts where safe non-ototoxic alternative drugs are not yet available.

OBJECTIVES

The goal was to investigate the impact of medical intervention strategies for reducing the ototoxic effects of long-term use of aminoglycosides for the treatment of Multi-Drug Resistant Tuberculosis (MDR-TB) in adults at a rural hospital in the Eastern Cape, South Africa.

METHODS

A retrospective record review with a control group design was used, with audiological and medical record reviews of all participants' files over a six-month period. A total of 86 participants (intervention group n=32 and control group n=54) were included. Descriptive and inferential statistics were used to analyze the data.

RESULTS

Results revealed progressive hearing loss in both groups, with worsening of thresholds at each subsequent assessment session. The progression of the hearing loss, however, was much slower in the intervention group, with degree of hearing loss being more severe in the control group in the final session of assessment (36.78-71.74dB), when compared to the intervention group (33-44.39dB). Furthermore, the hearing loss in the intervention group remained in the high frequencies while that in the control group progressed to involve the lower frequencies on the audiogram. The most common medical intervention strategies employed in the current study were to reduce the dosage of the ototoxic drug (61%), with the daily dosage reduced to 800mg in 39% of participants, while the administration of the drug was reduced from daily to thrice weekly in 22% of participants.

CONCLUSIONS

The results reveal better hearing sensitivity over the treatment period in the intervention group when compared to the control group; thus suggesting that early medical strategies implemented had a significant preventive impact. Current findings are relevant to the audiological, medical and pharmaceutical fields, particularly within the South African context where resource constraints are a consideration in all treatment measures.

Validating the surgical indication value of the LTB-S classification system for drug resistant tuberculosis

BACKGROUND

Currently there is no guideline based on preoperative clinical parameters for assessing the prognosis of the adjunctive surgery for drug-resistant tuberculosis.

METHODS

We retrospectively analyzed 138 patients who had undergone surgical resection as a treatment for drug- resistant tuberculosis after 24 months. Four clinical parameters on lesion type, treatment history, body physiological status, and surgery approach were evaluated. Categorical preoperative clinical parameters were analyzed by ordinal logistic regression model when considering postoperative complications as outcomes ordered in terms of severity. Statistically significant parameters were then combined in a single classification system for predicting the outcomes of the adjunctive surgery.

FINDINGS

Diffused, progressive bilateral lesions, or active/progressive extra pulmonary tuberculosis (L3), and history of less than 2 months treatment before surgery (T3) were the strongest predicative parameters for postoperative complications and for surgery failure. Classification systems based on the four parameters were found to have a statistically significant effect on postoperative complications and postoperative efficacy. 24- month follow up indicated a high cure rate (above 95.5%) among patients without T3, L3, or severe physiological complications (B3).

INTERPRETATION

A classification system based on objective clinical parameters showed predicative value for the prognosis of the adjunctive surgery and could guide management of drug-resistant Tuberculosis.

Surveillance for multi-drug and rifampicin resistant tuberculosis and treatment outcomes among previously treated persons with tuberculosis in the era of GeneXpert in rural eastern Uganda

Rationale

Previously treated persons with bacteriologically confirmed pulmonary tuberculosis (BC-PTB) have increased risk of developing multi-drug resistant or rifampicin resistant tuberculosis (MDR/RR-TB). Surveillance for resistance is critical to identify and treat MDR/RR-TB to ensure cure and prevent transmission. There are limited studies conducted on this subject.

Objectives

We examined the frequency and factors associated with MDR/RR-TB surveillance among previously treated persons with BC-PTB, and described their treatment outcomes in rural eastern Uganda.

Methods

We reviewed treatment records for BC-PTB between January 2015 and June 2018 at 10 clinics in eastern Uganda. We collected data on demographics, surveillance for MDR/RR, use of GeneXpert and treatment outcomes. We performed bivariate and multivariate analyses. For multivariate analysis, we used the modified Poisson regression analysis with robust standard errors and stated the results as adjusted risk ratio (aRR) with 95% confidence intervals (CI). All analyses were conducted in R version 3.5.2.

Measurements and main results

We obtained records for 135 previously treated persons with BC-PTB and of these, 41 (30.4%) had undergone surveillance for MDR/RR-TB. Treatment failures were less likely to have surveillance compared to relapses (aRR, 0.28; 95% CI, 0.08-0.95), and there was an increasing trend in the likelihood for surveillance between 2015 and 2018 (aRR, 1.77; 95% CI, 1.39-2.25). There was no difference in MDR/RR-TB surveillance rate between health facilities with and without GeneXpert on-site (aRR, 1.52; 95% CI, 0.81-2.86) and between male and female patients (aRR, 0.54; 95% CI, 0.21-1.37). Overall, 92 (68.1%) previously treated persons with BC-PTB were successfully treated for tuberculosis.

Conclusions

MDR/RR-TB surveillance and treatment success rates among previously treated persons with BC-PTB in rural eastern Uganda are low. Tuberculosis programs should strengthen MDR/RR-TB surveillance and especially target those with treatment failure.

Exacerbation of eosinophilic COPD and pneumonia in post-treatment pulmonary multidrug-resistant tuberculosis patient: A case report

Eosinophilic chronic obstructive pulmonary disease (COPD) is a COPD phenotype with several clinical characteristics such as eosinophilic airway inflammation, more common in men and less severe COPD. Eosinophilic COPD has more exacerbations but responds well to corticosteroids and bronchodilators. We hereby report the case of a patient who came to us with shortness of breath, fever, wheezing and a cough with yellow phlegm. He had a history of smoking 4.5 pack-year and two episodes of pulmonary tuberculosis (the second was pulmonary multidrug-resistant tuberculosis). He was diagnosed with eosinophilic COPD exacerbation and pneumonia. Intravenous corticosteroids, bronchodilators and antibiotics were given and his condition improved after a week of hospitalisation. Smoking and pulmonary tuberculosis are risk factors for COPD. In this case, irreversible airflow obstruction is related to COPD and also pulmonary TB. There are several mechanisms that cause airway obstruction in pulmonary tuberculosis, one of which is persistent mycobacterium acting as a co-factor along with smoking and several environmental factors that cause chronic airway inflammation and result in bronchial narrowing with or without parenchymal destruction.

Catastrophic costs of treating drug resistant TB patients in a tertiary care hospital in India

BACKGROUND

Private healthcare is choice of point of care for 70% of Indians. Multidrug resistant tuberculosis (MDR-TB) treatment is costly and involves duration as long as 2 years.

AIM

To estimate costs to patients undergoing treatment for MDR-TB.

METHODS

A health-economics questionnaire was administered to 50 consecutive patients who successfully completed ambulatory private treatment for MDR-TB. Direct costs included drug costs, investigations, consultation fees, travel costs, hospitalisation and invasive procedures and cost prior to presentation to us. Indirect costs included loss of income.

RESULTS

Of our cohort of 50 patients, 36 had pulmonary TB while 14 had extra-pulmonary TB (EPTB). 40 had MDR-TB and 10 had XDR-TB. There were 15 males and 35 females. Mean age was 30 years (range 16-61 years). Treatment cost for pulmonary MDR-TB averaged $5723 while it averaged $8401 for pulmonary XDR-TB and $5609 for EPTB. The major expense was due to drug costs (37%) while consultation fees were only 5%. Annual individual income for the cohort ranged from $0 to $63,000 (mean $11,430). On average, the cost of treatment ranged from 2.56% to 180.34% of the annual family income. 34/50 (68%) had total costs greater than 20% of annual family income and 39/50 (78%) had total costs greater than 10% of annual family income. The number of patients with total costs >40% of total family income was 22.

CONCLUSION

MDR-TB in the private sector results in "catastrophic health costs". Financial and social support is essential for patients undergoing treatment for MDR-TB.

The critically ill patient with tuberculosis in intensive care: Clinical presentations, management and infection control

Tuberculosis (TB) is one of the top ten causes of death worldwide. In 2016, there were 490,000 cases of multi-drug resistant TB globally. Over 2 billion people have asymptomatic latent Mycobacterium tuberculosis infection. TB represents an important, but neglected management issue in patients presenting to intensive care units. Tuberculosis in intensive care settings may present as the primary diagnosis (active drug sensitive or resistant TB disease). In other patients TB may be an incidental co-morbid finding as previously undiagnosed sub-clinical or latent TB which may re-activate under conditions of stress and immunosuppression. In Sub-Saharan Africa, where co-infection with the human immunodeficiency virus and other communicable diseases is highly prevalent, TB is one of the most frequent clinical management issues in all healthcare settings. Acute respiratory failure, septic shock and multi-organ dysfunction are the most common reasons for intensive care unit admission of patients with pulmonary or extrapulmonary TB. Poor absorption of anti-TB drugs occurs in critically ill patients and worsens survival. The mortality of patients requiring intensive care is high. The majority of early TB deaths result from acute cardiorespiratory failure or septic shock. Important clinical presentations, management and infection control issues regarding TB in intensive care settings are reviewed.

Analysis of multi drug resistant tuberculosis (MDR-TB) financial protection policy: MDR-TB health insurance schemes, in Chhattisgarh state, India

INTRODUCTION

There are significant financial barriers to access treatment for multi drug resistant tuberculosis (MDR-TB) in India. To address these challenges, Chhattisgarh state in India has established a MDR-TB financial protection policy by creating MDR-TB benefit packages as part of the universal health insurance scheme that the state has rolled out in their effort towards attaining Universal Health Coverage for all its residents. In these schemes the state purchases health insurance against set packages of services from third party health insurance agencies on behalf of all its residents. Provider payment reform by strategic purchasing through output based payments (lump sum fee is reimbursed as per the MDR-TB benefit package rates) to the providers - both public and private health facilities empanelled under the insurance scheme was the key intervention.

AIM

To understand the implementation gap between policy and practice of the benefit packages with respect to equity in utilization of package claims by the poor patients in public and private sector.

METHODS

Data from primary health insurance claims from January 2013 to December 2015, were analysed using an extension of 'Kingdon's multiple streams for policy implementation framework' to explain the implementation gap between policy and practice of the MDR-TB benefit packages.

RESULTS

The total number of claims for MDR-TB benefit packages increased over the study period mainly from poor patients treated in public facilities, particularly for the pre-treatment evaluation and hospital stay packages. Variations and inequities in utilizing the packages were observed between poor and non-poor beneficiaries in public and private sector. Private providers participation in the new MDR-TB financial protection mechanism through the universal health insurance scheme was observed to be much lower than might be expected given their share of healthcare provision overall in India.

CONCLUSION

Our findings suggest that there may be an implementation gap due to weak coupling between the problem and the policy streams, reflecting weak coordination between state nodal agency and the state TB department. There is a pressing need to build strong institutional capacity of the public and private sector for improving service delivery to MDR-TB patients through this new health insurance mechanism.

Factors predicting treatment success in multi-drug resistant tuberculosis patients treated under programmatic conditions

BACKGROUND

Treatment success in multi-drug resistant tuberculosis under programmatic conditions has been far from satisfactory. Knowledge of the factors predicting treatment outcome can guide us to take appropriate corrective measures for better results. However, there is a scarcity of data on these predictors in Indian patients. The present study was sought to evaluate association of different patient and disease specific factors with treatment outcome in MDR-TB patients.

METHODS

It was a retrospective study that involved evaluation of data of MDR-TB patients who were started on Cat-IV treatment between January 2012 and December 2014. Medical records of 256 patients were scrutinized and necessary information on possible predicting factors like age, gender, body mass index, co-morbidities, previous TB treatment, blood investigations, treatment adherence, culture conversion time, etc. was retrieved. These factors were analyzed for their possible association with treatment outcome.

RESULTS

Of the 256 patients, 132 (51.6%) achieved successful outcome after Cat-IV anti-TB regimen. On multivariate logistic regression analysis age (adjusted OR=0.95; 95% CI 0.91-0.98; p=0.01), serum albumin level (adjusted OR=3.71; 95% CI: 1.22-11.3; p=0.02) and treatment adherence (adjusted OR=4.52; 95% CI: 1.2-16.6; p=0.02) were independently associated with treatment success. Co-morbidities like diabetes and alcoholism and previous anti-TB treatment didn't affect the treatment end result significantly.

CONCLUSION

The treatment outcome in MDR-TB has not significantly improved since the inception of DOTS-Plus strategy. Interventions to improve nutrition and treatment adherence might help to improve the success rate in MDR-TB treatment.

Should all suspected tuberculosis cases in high income countries be tested with GeneXpert?

In countries with a low incidence of multidrug-resistant tuberculosis (MDR-TB), universal testing with GeneXpert might not be always cost-effective. This study provides hospital managers in low MDR-TB incidence countries with criteria on when decentralised universal GeneXpert testing would make sense. The alternatives taken into consideration include: universal microbiological culture and drug susceptibility testing (DST) only (comparator); as above but with concurrent centralized GeneXpert in a referral laboratory vs a decentralized GeneXpert system in every hospital to test smear-positive cases only; as above but testing all samples with GeneXpert regardless of smear status. The parameters were from the national TB statistics for England and from a systematic review. Decentralised GeneXpert to test any suspected TB case was the most cost-effective option when 6% or more TB patients belonged to the high-risk group, defined as previous TB diagnosis and or being born in countries with a high MDR-TB incidence. Hospital managers in England and other low MDR-TB incidence countries could use these findings to decide when to invest in GeneXpert or other molecular diagnostics with similar performance criteria for TB diagnostics.

Proceedings from the CIHLMU 5th Infectious Diseases Symposium 2016 "Drug Resistant Tuberculosis: Old Disease - New Challenge"

The 5th CIH^LMU Infectious Disease Symposium, Munich, Germany, March 12, 2016 brought together Tuberculosis Experts from developed and low middle-income countries to discuss the control of drug resistance Tuberculosis. The meeting featured 9 presentations: Tuberculosis history and current scenario, Tuberculosis and migration - current scenario in Germany, Mechanism of Tuberculosis resistance development, Epidemiology of resistance - transmission vs. new generation of resistance, The impact of diagnostic in patients beyond - sensitivity and specificity, The Bangladesh regimen - new hope trough old drugs, New drugs and regimens - an overview on studies and Multi and Extensively Drug Resistant Tuberculosis from Europe. The presentations were followed by a panel discussion. Serious Multidrug Resistance epidemic in some countries may jeopardize the progress in Tuberculosis control. In this meeting epidemiology, mechanism, immigration and screening, diagnosis, research and treatment of drug resistant tuberculosis were discussed.

Outcomes from patients with presumed drug resistant tuberculosis in five reference centers in Brazil

Background

The implementation of rapid drug susceptibility testing (DST) is a current global priority for TB control. However, data are scarce on patient-relevant outcomes for presumptive diagnosis of drug-resistant tuberculosis (pDR-TB) evaluated under field conditions in high burden countries.

Methods

Observational study of pDR-TB patients referred by primary and secondary health units. TB reference centers addressing DR-TB in five cities in Brazil. Patients age 18 years and older were eligible if pDR-TB, culture positive results for Mycobacterium tuberculosis and, if no prior DST results from another laboratory were used by a physician to start anti-TB treatment. The outcome measures were median time from triage to initiating appropriate anti-TB treatment, empirical treatment and, the treatment outcomes.

Results

Between February,16th, 2011 and February, 15th, 2012, among 175 pDR TB cases, 110 (63.0%) confirmed TB cases with DST results were enrolled. Among study participants, 72 (65.5%) were male and 62 (56.4%) aged 26 to 45 years. At triage, empirical treatment was given to 106 (96.0%) subjects. Among those, 85 were treated with first line drugs and 21 with second line. Median time for DST results was 69.5 [interquartile - IQR: 35.7–111.0] days and, for initiating appropriate anti-TB treatment, the median time was 1.0 (IQR: 0–41.2) days. Among 95 patients that were followed-up during the first 6 month period, 24 (25.3%; IC: 17.5%–34.9%) changed or initiated the treatment after DST results: 16/29 MDRTB, 5/21 DR-TB and 3/45 DS-TB cases. Comparing the treatment outcome to DS-TB cases, MDRTB had higher proportions changing or initiating treatment after DST results (p = 0.01) and favorable outcomes (p = 0.07).

Conclusions

This study shows a high rate of empirical treatment and long delay for DST results. Strategies to speed up the detection and early treatment of drug resistant TB should be prioritized.

Emergence of fluoroquinolone resistance among drug resistant tuberculosis patients at a tertiary care facility in Karachi, Pakistan

Background

Pakistan is classified as one of the high multi-drug resistant tuberculosis (MDR-TB) burden countries. A poorly regulated private sector, over-prescription of antibiotics and self-medication has led to augmented rates of drug-resistance in the country. Pakistan’s first national anti-tuberculosis drug resistance survey identified high prevalence of fluoroquinolone resistance among MDR-TB patients. Further institutional evidence of fluoroquinolone drug-resistance can support re-evaluation of treatment regimens as well as invigorate efforts to control antibiotic resistance in the country.

Findings

In this study, data for drug-susceptibility testing (DST) was retrospectively analyzed for a total of 133 patients receiving MDR-TB treatment at the Chest Department of Jinnah Postgraduate Medical Center, Karachi, Pakistan. Frequency analyses for resistance patterns was carried out and association of fluoroquinolone (ofloxacin) resistance with demographics and past TB treatment category were assessed. Within first-line drugs, resistance to isoniazid was detected in 97.7% of cases, followed by rifampicin (96.9%), pyrazinamide (86.4%), ethambutol (69.2%) and streptomycin (64.6%). Within second-line drugs, ofloxacin resistance was detected in 34.6% of cases. Resistance to ethionamide and amikacin was 2.3% and 1.6%, respectively. Combined resistance of oflaxacin and isoniazid was detected in 33.9% of cases. Age, gender and past TB treatment category were not significantly associated with resistance to ofloxacin.

Conclusion

Fluoroquinolone resistance was observed in an alarmingly high proportion of MDR-TB cases. Our results suggest caution in their use for empirical management of MDR-TB cases and recommended treatment regimens for MDR-TB may require re-evaluation. Greater engagement of private providers and stringent pharmacy regulations are urgently required.

Towards understanding the drivers of policy change: a case study of infection control policies for multi-drug resistant tuberculosis in South Africa

Background

Explaining policy change is one of the central tasks of contemporary policy analysis. In this article, we examine the changes in infection control policies for multi-drug resistant tuberculosis (MDR-TB) in South Africa from the time the country made the transition to democracy in 1994, until 2015. We focus on MDR-TB infection control and refer to decentralised management as a form of infection control. Using Kingdon’s theoretical framework of policy streams, we explore the temporal ordering of policy framework changes. We also consider the role of research in motivating policy changes.

Methods

Policy documents addressing MDR-TB in South Africa over the period 1994 to 2014 were extracted. Literature on MDR-TB infection control in South Africa was extracted from PubMed using key search terms. The documents were analysed to identify the changes that occurred and the factors driving them.

Results

During the period under study, five different policy frameworks were implemented. The policies were meant to address the overwhelming challenge of MDR-TB in South Africa, contextualised by high prevalence of HIV infection, that threatened to undermine public health programmes and the success of antiretroviral therapy rollouts. Policy changes in MDR-TB infection control were supported by research evidence and driven by the high incidence and complexity of the disease, increasing levels of dissatisfaction among patients, challenges of physical, human and financial resources in public hospitals, and the ideologies of the political leadership. Activists and people living with HIV played an important role in highlighting the importance of MDR-TB as well as exerting pressure on policymakers, while the mass media drew public attention to infection control as both a cause of and a solution to MDR-TB.

Conclusion

The critical factors for policy change for infection control of MDR-TB in South Africa were rooted in the socioeconomic and political environment, were supported by extensive research, and can be framed using Kingdon’s policy streams approach as an interplay of the problem of the disease, political forces that prevailed and alternative proposals.

Tuberculosis cases caused by heterogeneous infection in Eastern Europe and their influence on outcomes

INTRODUCTION

Mycobacterium tuberculosis superinfection is known to occur in areas with high rates of tuberculosis (TB) and has a significant impact on overall clinical TB management.

AIM

We aimed to estimate the superinfection rate in cohorts of drug sensitive and multi-drug resistant tuberculosis (MDR TB) patients from Eastern Europe and the potential role of a second MDR TB strain infecting a patient with active non-MDR TB in treatment outcome.

METHODS

The study population included 512 serial M. tuberculosis isolates obtained from 84 MDR- and 136 non-MDR TB patients recruited sequentially at sites in Lithuania, Latvia and Russia in 2011-2013. Strains were genotyped using standardized 24-loci Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeat (MIRU-VNTR) typing.

RESULTS

Changes in two or more MIRU-VNTR loci suggesting superinfection were detected in 13 patients (5.9%). We found 4 initially non-MDR TB patients superinfected with an MDR TB strain during treatment and 3 of them had an unsuccessful outcome.

CONCLUSIONS

An unsuccessful treatment outcome in patients initially diagnosed with drug sensitive TB might be explained by superinfection with an MDR TB strain. Bacteriological reversion could be indicative of superinfection with another strain. Archiving of all serial isolates and their genotyping in case of culture reversion could support therapeutic strategies in high MDR TB burden settings if resources are available.

Where there is hope: a qualitative study examining patients' adherence to multi-drug resistant tuberculosis treatment in Karakalpakstan, Uzbekistan

Background

Treatment for multi-drug resistant tuberculosis (MDR-TB) is lengthy, has severe side effects, and raises adherence challenges. In the Médecins Sans Frontières (MSF) and Ministry of Health (MoH) programme in Karakalpakstan, Uzbekistan, a region with a high burden of MDR-TB, patient loss from treatment (LFT) remains high despite adherence support strategies. While certain factors associated with LFT have been identified, there is limited understanding of why some patients are able to adhere to treatment while others are not. We conducted a qualitative study to explore patients’ experiences with MDR-TB treatment, with the aim of providing insight into the barriers and enablers to treatment-taking to inform future strategies of adherence support.

Methods

Participants were purposively selected. Programme data were analysed to enable stratification of patients by adherence category, gender, and age. 52 in-depth interviews were conducted with MDR-TB patients (n = 35) and health practitioners (n = 12; MSF and MoH doctors, nurses, and counsellors), including five follow-up interviews. Interview notes, then transcripts, were analysed using coding to identify emerging patterns and themes. Manual analysis drew upon principles of grounded theory with constant comparison of codes and categories within and between cases to actively seek discrepancies and generate concepts from participant accounts. Ethics approval was received from the MoH of the Republic of Uzbekistan Ethics Committee and MSF Ethics Review Board.

Results

Several factors influenced adherence. Hope and high quality knowledge supported adherence; autonomy and control enabled optimal engagement with treatment-taking; and perceptions of the body, self, treatment, and disease influenced drug tolerance. As far as we are aware, the influence of patient autonomy and control on MDR-TB treatment-taking has not previously been described. In particular, the autonomy of married women around treatment-taking was potentially undermined through their societal position as daughter-in-law, compromising their ability to adhere to treatment. Patients’ engagement with and adherence to treatment could be hindered by hierarchical practitioner-patient relationships that displaced authority, ownership, and responsibility from the patient.

Conclusions

Our findings reinforce the need for an individualised and holistic approach to adherence support with engagement of patients as active participants in their care who feel ownership and responsibility for their treatment.

Uniting to end the TB epidemic: advances in disease control from prevention to better diagnosis and treatment

Tuberculosis is a major global cause of morbidity and mortality. Despite recent advances in containing the epidemic, several challenges continue to slow progress towards elimination including the continuing impact of drug resistant disease, and the lack of appropriate tools. Curtailing the transmission of tuberculosis remains a challenge especially in high burden countries. New developments in measuring correlates of protection are urgently needed to support the evaluation of vaccines. Similarly, despite progress in molecular diagnostics, better tools are required to identify resistance to antibiotics in multi and extensively drug resistant tuberculosis. Whole Genome Sequencing may lead to the next generation of assays to rapidly detect resistance and evaluate transmission. Advances on shortening treatment are hampered by the lack of a biomarker of cure which obviates the current long wait for relapses in trials. New research is urgently needed to support development of new vaccines and better diagnostics tools and shorter treatment for drug sensitive and resistant tuberculosis.

Prevalence and Risk Factors of Primary Drug-Resistant Tuberculosis in China

OBJECTIVE

To investigate the prevalence of primary drug-resistant tuberculosis (TB) and associated risk factors in China. We also explored factors contributing to the transmission of multidrug-resistant tuberculosis (MDR-TB).

METHODS

A total of 2794 representative, Mycobacterium tuberculosis isolates from treatment-naive patients were subjected to drug susceptibility testing, and risk factors for drug-resistant TB were analyzed. We also analyzed MDR-TB strain sublineages, drug-resistance-conferring mutations, and risk factors associated with clustered primary MDR strains.

RESULTS

Among 2794 Mycobacterium tuberculosis isolates from treatment-naive patients, the prevalence of any resistance to first-line drugs was 33.2% and the prevalence of MDR-TB was 5.7%. We did not find any risk factors significantly associated with resistance to first-line drugs. The 93 primary MDR-TB isolates were classified into six sublineages, of which, 75 (80.6%) isolates were the RD105-deleted Beijing lineage. The largest sublineage included 65 (69.9%) isolates with concurrent deletions of RD105, RD207, and RD181. Twenty-nine (31.2%) primary MDR strains grouped in clusters; MDR isolates in clusters were more likely to have S531L rpoB mutation.

CONCLUSION

This study indicates that primary drug-resistant TB and MDR-TB strains are prevalent in China, and multiple measures should be taken to address drug-resistant TB.

Prevalence and characterization of drug-resistant tuberculosis in a local hospital of Northeast China

OBJECTIVES

To investigate the distribution and risk factors associated with drug-resistant tuberculosis (TB) at a local hospital in Northeast China.

METHODS

A total of 205 patients with TB were enrolled in the study from March 8, 2010 to July 13, 2011. Mycobacterium tuberculosis (MTB) strains isolated from patients were subjected to drug susceptibility testing by proportion method.

RESULTS

Among the 205 patients with MTB, 54 (26.3%) had isolates that showed resistance to at least one drug. The overall prevalence of multidrug-resistant TB (MDR-TB) was 6.8% (n = 14) (3.0% of newly diagnosed patients and 22.0% of previously treated cases). Importantly, an extensively drug-resistant TB (XDR-TB) isolate was found, which was isolated from a newly treated patient. Eleven (5.4%) were infected with a poly-resistant strain of MTB (5.5% of newly diagnosed patients and 4.9% of previously treated cases). The mono-resistance rates of isoniazid, rifampin, ethambutol, streptomycin, ofloxacin, and kanamycin were 3.4%, 1.5%, 2.4%, 3.9%, 2.4%, and 0.5%, respectively. Certain groups, including previously treated patients and male patients, were more likely to develop drug-resistant TB.

CONCLUSIONS

The results of this analysis of drug resistance in MTB reflect the situation in a local hospital and indicate that the morbidity related to TB, especially MDR-TB, is still a serious health problem. Thus, the timely detection of drug resistance is of great importance to optimize treatment and to direct infection control measures to block the transmission of MDR-TB.