Predictors of sputum culture conversion among patients treated for multidrug-resistant tuberculosis

Predictors of early and interim culture un-conversion in multidrug-resistant/rifampicin-resistant tuberculosis: a retrospective multi-center cohort study in China

BACKGROUND

We aimed to evaluate the predictors for early and interim culture conversion within 2 months and 6 months of treatment in multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) patients in China.

METHODS

This study included adult MDR/RR-TB patients with a positive baseline sputum culture from 8 institutions located in different cities in China from May 2018 to January 2022. We mainly used logistic regression model to derive possible predictors of early and interim culture conversion.

RESULTS

A total of 813 patients were enrolled and 28.5% of them received multidrug-resistant treatment regimens containing bedaquiline. Of these, 362 (44.5%) patients experienced culture conversion within 2 months of treatment, and 649 (79.8%) within 6 months. The results of the multivariable logistic regression analysis revealed that acid-fast bacilli smear positive (adjusted odds ratio [aOR] = 1.637, 95% confidence interval [CI] = 1.197-2.238), cavities (aOR = 1.539, 95% CI = 1.132-2.092), bilateral disease (aOR = 1.638, 95% CI = 1.183-2.269), and viral hepatitis (aOR = 2.585, 95% CI = 1.189-5.622) were identified as risk factors for early culture un-conversion within 2 months of treatment. Additionally, smoking history (aOR = 2.197, 95% CI = 1.475-3.273), previous treatment for tuberculosis (aOR = 1.909, 95% CI = 1.282-2.844), bilateral disease (aOR = 2.201, 95% CI = 1.369-3.537), viral hepatitis (aOR = 2.329, 95% CI = 1.094-4.962) were identified as risk factors for interim culture un-conversion within 6 months of treatment, while patients with regimen containing bedaquiline (aOR = 0.310, 95% CI = 0.191-0.502) was a protective factor.

CONCLUSIONS

A history of smoking, a baseline sputum AFB smear positive, lung cavities, bilateral disease, previous anti-tuberculosis treatment, or a comorbidity of viral hepatitis can be used as the predictors for early and interim culture un-conversion in MDR/RR-TB patients, while bedaquiline was a protective factor .

A blood-based 3-gene signature score for therapeutic monitoring in patients with pulmonary tuberculosis

OBJECTIVE

To assess the validity of Xpert Tuberculosis Fingerstick score for monitoring treatment response and analyze factors influencing its performance.

METHODS

122 adults with pulmonary tuberculosis were recruited and stratified into three cohorts: Diabetic-drug-susceptible-TB (DM-TB), Non-diabetic-drug-susceptible-TB (NDM-TB) and Non-diabetic Multidrug-resistant TB (MDR-TB). Fingerstick blood specimens were tested at treatment initiation (M0) and the end of the first (M1), second (M2), and sixth month (M6) to generate a TB-score.

RESULTS

The TB-score in all participants yielded an AUC of 0.707 (95% CI: 0.579-0.834) at M2 when its performance was evaluated against sputum culture conversion. In all non-diabetes patients, the AUC reached 0.88 (95% CI: 0.756-1.000) with an optimal cut-off value of 1.95 at which sensitivity was 90.0% (95% CI: 59.6-98.2%) and specificity was 81.3% (95% CI: 70.0-88.9%). The mean TB score was higher in patients with low bacterial loads (n = 31) than those with high bacterial loads (n = 91) at M0, M1, M2, and M6, and was higher in non-cavitary patients (n = 71) than those with cavitary lesions (n = 51) at M0, M1, and M2.

CONCLUSION

Xpert TB-score shows promising predictive value for culture conversion in non-diabetic TB patients. Sputum bacterial load and lung cavitation status have an influence on the value of TB score.

Evaluation of time to sputum smear conversion and its association with treatment outcomes among drug-resistant tuberculosis patients: a retrospective record-reviewing study

Background: This study examined the time to sputum smear and culture conversion and determinants of conversion, as well as variables associated with treatment outcomes among drug-resistant pulmonary tuberculosis (DR-PTB) cases. Methods: The electronic database and written medical records of patients were utilized to assess the sociodemographic, clinical, microbiological, and treatment characteristics and outcomes of study participants. Results: Among 736 patients with pulmonary tuberculosis (PTB), the mean age was 36.5 ± 16.5 years, with males comprising 53.4% and a mean weight of 47.76 ± 11.97 kg. The median time period for sputum smear conversion and sputum culture conversion was a month. The first-month culture conversion (p < 0.001, aOR = 5.817, and 95% CI = 3.703-9.138) was the determinant of sputum smear conversion and receiver operating curve analysis with AUC = 0.881, 95% CI = 0.855-0.907, and p < 0.001, which showed a high level of predictive ability for the regression model for the initial sputum smear conversion. However, the first-month sputum conversion (p < 0.001, aOR = 7.446, and 95% CI = 4.869-11.388) was attributed to sputum culture conversion, and the model has shown excellent predictive ability for regression with ROC curve analysis demonstrating AUC = 0.862, 95% CI = 0.835-0.889, and p < 0.001. A total of 63.2% of patients showed favorable treatment outcomes, with 63.1% of cases achieving treatment-cured status. The previous use of SLD, history of smoking, duration of illness ≤ 1 year, extensively drug-resistant tuberculosis, and first-month sputum conversion were the variables attributed to favorable treatment outcomes observed in drug-resistant pulmonary tuberculosis cases. ROC curve analysis with AUC = 0.902, 95% CI = 0.877-0.927, and p < 0.001) has shown outstanding ability for regression model prediction for the variables influencing treatment outcomes. Conclusions: Within 2 months of treatment, most patients had converted their sputum cultures and sputum smears. The determinants of early sputum smear and sputum culture conversion, as well as favorable treatment outcomes, were identified. These factors should be considered during the design and implementation of effective strategies for drug-resistant tuberculosis control programs.

Determinants of sputum culture conversion time in multidrug-resistant tuberculosis patients in ALERT comprehensive specialized hospital, Addis Ababa, Ethiopia: A retrospective cohort study

INTRODUCTION

The treatment response of multi-drug resistance tuberculosis (MDR-Tuberculosis) patients is mainly dictated by the sputum culture conversion. An earlier culture conversion is a remarkable indicator of the improvement in the treatment response. In this study, we aimed to determine the time to culture conversion and its associated factors among MDR-Tuberculosis patients in All Africa Leprosy, Tuberculosis and Rehabilitation Training Center (ALERT) Hospital, Addis Ababa, Ethiopia.

METHODS

A retrospective cohort study was conducted on 120 MDR-Tuberculosis patients attending ALERT Hospital from 2018-2022. Kaplan-Meier methods were used to determine the time to initial sputum culture conversion. All relevant laboratory, socio-demographic characteristics, and other clinical data were collected by chart abstraction using a structure data extraction form. The log-rank test was used to determine the survival rate. To identify the predictors of culture conversion, bivariate and multivariate Cox proportional hazard regression analysis was used. The hazard ratio (HR) with a 95% confidence interval was used to estimate the effect of each variable on the initial culture conversion. A test with a P value of < 0.05 was considered statistically significant.

RESULTS

From the total of 120 study participants, 89.2% (107/120) have shown a successful culture conversion. The median age of the participants was 30 years (IQR = 12). The study participants were followed for 408.6 person-months (34.05 person-years). The median time to initial sputum culture conversion was 80 days. The median time to initial sputum culture conversion among HIV-positive and HIV-negative participants was 61 days (IQR = 58-63.5) and 88 days (IQR = 75-91), respectively. HIV-negative and patients with previous treatment history were shown to be the predictor for a prolonged time to initial sputum culture conversion, (aHR = 0.24 (95% CI: 0.1-0.4), P value <0.001) and (aHR = 0.47 (95% CI: 0.31-0.71), P value <0.001) respectively.

CONCLUSION

The median time to sputum culture conversion for HIV positive was found to be 61 days in our study. Notably, patients with a history of previous anti-tuberculosis treatment, HIV-negative status, and higher bacillary load at baseline exhibited delayed culture conversion. These findings underscore the importance of considering such patient characteristics in the management of MDR-TB cases, as tailored interventions and close monitoring may lead to more favorable treatment outcomes. By identifying individuals with these risk factors early in the treatment process, healthcare providers can implement targeted strategies to optimize patient care and improve overall treatment success rates in MDR-TB management programs.

Time to Sputum Culture Conversion and Its Predictors Among Multidrug Resistant Tuberculosis Patients in Tigray, Northern Ethiopia: Retrospective Cohort Study

Background

Sputum culture conversion status is a cardinal index of treatment response and patient outcome for MDR TB patients on longer anti-TB drugs. But, there is limited information on time to sputum culture conversion of MDR TB patients on a longer anti-TB treatment regimen. Therefore, this study aimed to evaluate time to sputum culture conversion and its predictors among MDR TB patients in Tigray, Northern Ethiopia.

Methods

A retrospective cohort study was conducted from January 2017 through September 2020 among MDR TB patients in Tigray, Northern Ethiopia. Demographic and clinical characteristics including bacteriological data were extracted from the TB registration book and electronic database in Tigray Health Research Institute. Statistical analysis was performed using SPSS version 25. The time to initial sputum culture conversion was analyzed using the Kaplan-Meier method. Bivariate and multivariate Cox proportional hazards regression analyses were used to identify predictors for culture conversions. P <0.05 was considered statistically significant.

Results

A total of 294 eligible study participants with a median age of 30 years (IQR: 22.75-40) were included. The participants were followed for a total of 1066.7 person months. Sputum culture conversion was achieved in 269 (91%) of the study participants. The median time of sputum culture conversion was 64 days (IQR: 49-86). In our multivariate model, HIV-positive (aHR=1.529, 95% CI: 1.096-2.132, P=0.012), patients new to anti-TB treatment (aHR=2.093, 95% CI: 1.100-3.982, P=0.024) and baseline AFB smear grading of +1 (aHR=1.982, 95% CI: 1.428-2.750, P=0.001) significantly affected time to initial sputum culture conversion.

Conclusion

The median time of culture conversion was 64 days. Moreover, the majority of the study participants achieved culture conversion within the first six months of treatment commencement, which supports predefined standard treatment durations.

Serosal membrane tuberculosis in Iran: A comprehensive review of evidences

Tuberculosis (TB) is among the most common cause of serositis. There are many uncertainties in diagnostic and therapeutic approach to serous membranes tuberculosis. Our aim in the present review is to discuss the regional facilities for timely diagnosis, rapid decision-making and appropriate treatment regarding to serous membranes tuberculosis; with emphasis on situation in Iran. A comprehensive literature searches about the status of serous membranes tuberculosis in Iran were performed in English databases including Google Scholar, Science Direct, Scopus, Pub Med, and Web of Sciences, Persian SID databases, between 2000 and 2021. The main findings of the present review are as follow: a) pleural tuberculosis is more common than pericardial or peritoneal tuberculosis. b) Clinical manifestations are non-specific and so non-diagnostic. c) Smear and culture, PCR and characteristic granulomatous reaction have been used for definitive TB diagnosis by physicians. d) With Adenosine Deaminase Assays and Interferon-Gamma Release Assays in mononuclear dominant fluid, a possible diagnosis of TB is proposed by experienced physicians in Iran. e) In area of endemic for tuberculosis including Iran, a possible diagnosis of TB is enough to begin empirical treatment. f) In patients with uncomplicated tuberculosis serositis, treatment is similar to pulmonary tuberculosis. First line drugs are prescribed unless evidence of MDR-TB is detected. g) The prevalence of drug resistant tuberculosis (MDR-TB) in Iran is between 1% and 6%, and are treated by empirical standardized treatment. h) It is not known whether adjuvant corticosteroids are effective in preventing long term complication. i) Surgery may be recommended for MDR-TB. Tamponade or constrictive pericarditis and intestinal obstruction. In conclusion, it is recommended to consider serosal tuberculosis in patients who have unknown mononuclear dominant effusion and prolonged constitutional symptoms. Experimental treatment with first line anti-TB drugs can be started based on possible diagnostic findings.

Management of Polydrug-Resistant Tuberculosis

Background and Objectives: There is a lack of information regarding the effective duration of treatment necessary to prevent the development of acquired resistance when fluoroquinolones (FQ), and/or pyrazinamide (Z) resistance has occurred in patients with polydrug-resistant tuberculosis and isoniazid resistance. The management of these kinds of patients should be carried out in experienced centers according to drug susceptibility test results, clinical status of the patient and the extensity of the disease. Materials and Methods: We evaluated treatment regimens, treatment outcomes, and drug adverse effects in seven patients with polydrug-resistant tuberculosis, including those with Z and/or FQ resistance in a retrospective analysis Results: Regarding the patients with polydrug-resistant tuberculosis in addition to isoniazid (H) resistance, three had Z, two had FQ, and the remaining two had both Z and FQ resistance. In the intensive phase of the treatment, the patients were given at least four drugs according to drug susceptibility tests, and at least three drugs in the continuation phase. The duration of treatment was 9-12 months. Two of the patients were foreign nationals, and could not be followed up with due to returning to their home countries. Regarding the remaining five patients, three of them were terminated as they completed treatment, and two as cured. No recurrence was observed in the first year of the treatment. The most common, and serious drug side effect was seen for amikacin. Conclusions: In patients with polydrug-resistant TB, if Z and/or FQ resistance is detected in addition to H resistance, the treatment of these patients should be conducted on a case-by-case basis, taking into account the patient's resistance pattern, clinical condition, and disease prognosis. Close monitoring of the side effects will increase the success rate of the treatment.

Predictors of sputum culture conversion time among MDR/RR TB patients on treatment in a low-income setting

OBJECTIVE

This study aimed to assess the time to first culture conversion and its predictors among MDR/RR-TB cases enrolled in Dilchora Hospital.

METHOD

A retrospective cohort study was conducted among MDR/RR TB cases enrolled between January 2014 and December 2018. SPSS version 26 was used for analysis. Reports are presented using percentages and frequency. Independent predictors of time-to-culture conversion were identified using multivariate Cox proportional hazard regression. Adjusted and crude hazard ratio with 95% CI was used. P-value< 0.05 declared statistical significance.

RESULT

A total of 145 MDR/RR TB cases were included. The median time to culture conversion was at 2 months. Higher baseline hemoglobin [AHR:1.101(1.02-1.19)] and having a non-cavitary lesion on chest x-ray[AHR:1.803(1.15-2.83)] predicted a higher likelihood of early culture conversion. Resistance to at least one first-line anti-TB drug in addition to rifampicin was associated with a lower hazard of early culture conversion as compared to only rifampicin resistance[AHR: 0.577(0.37-0.91)].

CONCLUSION & RECOMMENDATION

A baseline hemoglobin level, chest x-ray finding of cavitation and resistance to rifampicin, and at least one additional drug predicted the time to culture conversion. A closer treatment monitoring and follow-up should be emphasized for those presenting with lower baseline hemoglobin, more drug resistance, and cavitation on chest x-ray.

Tuberculosis Treatment Monitoring and Outcome Measures: New Interest and New Strategies

Despite the advent of new diagnostics, drugs and regimens, tuberculosis (TB) remains a global public health threat. A significant challenge for TB control efforts has been the monitoring of TB therapy and determination of TB treatment success. Current recommendations for TB treatment monitoring rely on sputum and culture conversion, which have low sensitivity and long turnaround times, present biohazard risk, and are prone to contamination, undermining their usefulness as clinical treatment monitoring tools and for drug development. We review the pipeline of molecular technologies and assays that serve as suitable substitutes for current culture-based readouts for treatment response and outcome with the potential to change TB therapy monitoring and accelerate drug development.

The Correlations of Minimal Inhibitory Concentration Values of Anti-TB Drugs with Treatment Outcomes and Clinical Profiles in Patients with Multidrug-Resistant Tuberculosis (MDR-TB) in China

Objective

It is a challenge to obtain satisfactory treatment outcomes for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB); the study aims to correlate the Minimum Inhibitory Concentration (MIC) value of drugs with the outcome of patients with MDR/RR-TB to obtain an understanding for better regimens and optimal outcomes.

Methods

The patients diagnosed with MDR/RR-TB were retrospectively enrolled from January 1, 2018 to December 31, 2019, recorded clinical characteristics, MIC DST (Drug Susceptibility Test) results, and followed the treatment outcome. The data were analyzed on the correlations of MIC DST values with outcomes and clinical characteristics.

Results

A total of 276 patients with MDR/RR-TB were included, containing 98 cases (35.5%) with newly treated patients and 178 cases (64.5%) with re-treated patients. A total of 220 cases recorded treatment success (79.7%) and 49 cases recorded treatment failure or died. MIC values of isoniazid (H), moxifloxacin (Mfx), and ethionamide (Eto) in newly treated patients were lower than those in retreated patients, and resistance levels of Mfx and H were closely associated with the treatment outcome (P < 0.05) while those of other drugs had no close association with treatment outcome.

Conclusions

MIC values of some anti-TB drugs, such as fluoroquinolones (FQs) and H, can reflect the treatment outcome for patients with MDR/RR-TB, which can contribute to making regimens for better treatment outcomes.

Revised Definitions of Tuberculosis Resistance and Treatment Outcomes, France, 2006-2019

Definitions of resistance in multidrug-resistant tuberculosis (MDR TB) and extensively drug-resistant tuberculosis (XDR TB) have been updated. Pre-XDR TB, defined as MDR TB with additional resistance to fluoroquinolones, and XDR TB, with additional resistance to bedaquiline or linezolid, are frequently associated with treatment failure and toxicity. We retrospectively determined the effects of pre-XDR/XDR TB resistance on outcomes and safety of MDR TB treatment in France. The study included 298 patients treated for MDR TB at 3 reference centers during 2006-2019. Of those, 205 (68.8%) cases were fluoroquinolone-susceptible MDR TB and 93 (31.2%) were pre-XDR/XDR TB. Compared with fluoroquinolone-susceptible MDR TB, pre-XDR/XDR TB was associated with more cavitary lung lesions and bilateral disease and required longer treatment. Overall, 202 patients (67.8%) had favorable treatment outcomes, with no significant difference between pre-XDR/XDR TB (67.7%) and fluoroquinolone-susceptible MDR TB (67.8%; p = 0.99). Pre-XDR/XDR TB was not associated with higher risk for serious adverse events.

Development and validation of a nomogram for the prediction of late culture conversion among multi-drug resistant tuberculosis patients in North West Ethiopia: An application of prediction modelling

Introduction

Multi-drug resistant tuberculosis has impeded tuberculosis prevention and control due to its low treatment efficiency and prolonged infectious periods. Early culture conversion status has long been used as a predictor of good treatment outcomes and an important infection control metric, as culture-negative patients are less likely to spread tuberculosis. There is also evidence that suggests that delayed sputum conversion is linked to negative outcomes. Therefore, this study was aimed at developing a nomogram to predict the risk of late culture conversion in patients with multi-drug resistant tuberculosis using readily available predictors.

Objective

The objective of this study was to develop and validate a risk prediction nomogram for the prediction of late culture conversion among multi-drug resistant tuberculosis patients in North-West Ethiopia.

Methods

Multi-drug resistant tuberculosis data from the University of Gondar and the Debre Markos referral hospitals have been used and a total of 316 patients were involved. The analysis was carried out using STATA version 16 and R version 4.0.5 statistical software. Based on the binomial logistic regression model, a validated simplified risk prediction model (nomogram) was built, and its performance was evaluated by assessing its discriminatory power and calibration. Finally, decision curve analysis (DCA) was used to assess the generated model’s clinical and public health impact.

Results

Registration group, HIV co-infection, baseline BMI, baseline sputum smear grade, and radiological abnormalities were prognostic determinants used in the construction of the nomogram. The model has a discriminating power of 0.725 (95% CI: 0.669, 0.781) and a P-value of 0.665 in the calibration test. It was internally validated using the bootstrapping method, and it was found to perform similarly to the model developed on the entire dataset. The decision curve analysis revealed that the model has better clinical and public health impact than other strategies specified.

Conclusion

The developed nomogram, which has a satisfactory level of accuracy and good calibration, can be utilized to predict late culture conversion in MDR-TB patients. The model has been found to be useful in clinical practice and is clinically interpretable.

Alcohol drinking delays the rate of sputum smear conversion among DR-TB patients in northwest Ethiopia; A retrospective follow-up study

Background

Sputum smear microscopy is simple and feasible technique to assess the presence of acid-fast bacilli (AFB) in the respiratory tract of patients with Drug Resistance Tuberculosis (DR-TB). Conversion of sputum smear from positive to negative is considered as an interim indicator of efficacy of anti-tubercular treatment and the program effectiveness. Although evidences regarding the factors affecting the sputum smear conversion are available on drug susceptible TB patients, there is dearth of literature about smear conversion and its predictors among DR-TB patients in the study setting. Hence, shortening the time to sputum smear conversion is desirable to reduce the likelihood of mycobacterial transmission. This study has therefore aimed at estimating the median time of sputum smear conversion and to determine its predictors.

Methods

This was a retrospective follow-up study conducted among DR-TB patients registered for second-line anti-TB treatment in the four hospitals of Amhara regional state, Northwest Ethiopia. Of all patients enrolled to DR-TB treatment in the study setting from 2010 to 2017, 436 patients have been include for this study who fulfilled the eligibility criteria. The cox proportional hazard model was fitted and the adjusted hazard ratio (AHR) with 95% confidence interval (CI) and p <0.05 was used to declare statistical significance of the variables associated with the smear conversion.

Results

From the 436 patients with sputum smear positive at baseline, 351 (80.5%) converted sputum smear at a median time of 48 (IQR: 30–78) days. The median time of smear conversion was 59 (95% CI: 42, 74) and 44 (95% CI: 37, 54) days among patients who had and had no history of alcohol drinking, respectively. Similarly, the median time to smear conversion was 61 (95% CI: 36, 73) days among patients with comorbid conditions and 44 (95% CI: 38, 54) days among patients with no comorbid conditions. In the multi-variable analysis, only history of alcohol consumption [AHR = 0.66 (0.50, 0.87)] was found to delay significantly the rate of sputum smear conversion.

Conclusion

In our study, the median time of sputum smear conversion was with in the expected time frame of conversion. History of alcohol consumption was found to delay significantly the rate of sputum smear conversion. The DR-TB patients are strongly advised to avoid alcohol consumption.

Factors associated with treatment outcome of MDR/RR-TB patients treated with shorter injectable based regimen in West Java Indonesia

Background and aims

Multi drug or rifampicin resistant tuberculosis (MDR/RR-TB) is a major burden to TB prevention and eradication globally. Since 2016, WHO guidelines have included options for treating MDR/RR-TB with a standard regimen of 9 to 11 months duration (the ’shorter regimen’) rather than an individual regimen of at least 20 months. This regimen has been introduced in Indonesia since September 2017. Therefore, we aimed to determine the success rate and factors associated with the treatment outcome of shorter injectable based regimen in West Java province, Indonesia.

Methods

This was a retrospective cohort study of MDR/RR-TB patients aged over 18 years old who received the shorter injectable based regimen between September 2017 and December 2020. We defined successful outcomes as the combined proportion of patients who were cured or had complete treatment. While, unsuccessful outcomes were defined as the combined proportion of patients who died from any causes, failure, and loss to follow-up (LTFU).

Results

A total of 315 patients were included in this study. The success rate was 64.5%. Multivariate analysis showed male gender (aRR = 1.18, 95% CI 1.04 to 1.34) increased the chance of successful outcome, while malnutrition (aRR = 0.78, 95% CI 0.68 to 0.89), history of previous TB treatment (aRR = 0.80%CI 0.68 to 0.94), and time of culture conversion >2 months (aRR = 0.72 (95% CI 0.59 to 0.87) decreased the chance of successful outcome.

Conclusion

History of previous TB treatment, time of culture conversion >2 months, and malnutrition were independent factors that decrease the chance for success rate, while male gender increase the likelihood for success rate of patients treated by the shorter injectable based regimen.

Malnutrition is Associated with Delayed Sputum Culture Conversion Among Patients Treated for MDR-TB

Background

Clinicians use sputum culture conversion as an interim indicator of the efficacy of multi-drug resistant tuberculosis (MDR-TB) treatment and to determine treatment duration. Yet, limited studies have been published in Ethiopia.

Objective

The objective of this study was to determine the predictors of delayed culture conversion among patients receiving MDR-TB treatment at selected treatment centers in Ethiopia.

Patients and Methods

A multi-center observation study was conducted among MDR-TB patients in South and Southwestern Ethiopia from April 14 to May 14, 2019. The data of patients treated from January 2013 to July 2019 were reviewed using a data abstraction tool. The data were analyzed. Descriptive statistics was computed using SPSS version 21 software program. Cox regression was used to identify predictors of delayed culture conversion. Hazard ratios with a two-sided p-value <0.05 were considered statistically significant.

Results

Of 200 included MDR-TB patients, 108 (54%) were males. Majority,159 (79.5%) of the patients had a culture conversion time of less than two months, while 15 (7.5%) had delayed culture conversion (greater than 120 days). Patient’s registration group (after loss to follow- (adjusted hazard ratio (AHR)=16.215, 95% CI [3.839, 68.498]), after treatment failure (AHR=12.161, 95% CI [2.516, 58.793]), history of previous TB treatment (AHR=4.007, 95% CI [3.115, 62.990])) and low BMI (AHR= 1.257; 95% CI [0.725,1.547] were identified as a risk factors for delayed culture conversion.

Conclusion

Our finding showed that nearly 80% of the patients achieve sputum culture conversion by the second month of treatment. Delayed culture conversion was more likely among patients with malnutrition (BMI<18.5kg/m²), after treatment failure, previous TB treatment, and after lost to follow-up.

Predictors of Time to Sputum Culture Conversion Among Drug-Resistant Tuberculosis Patients in Oromia Region Hospitals, Ethiopia

Purpose

Multi-drug-resistant tuberculosis occurs when the tuberculosis bacteria develop resistance to at least the two most effective first-line anti-tuberculosis drugs, isoniazid and rifampicin. Sputum culture conversion is one of the indicators to monitor patients’ prognosis throughout the treatment. Hence, this study aimed to assess time to culture conversion and its determinants among drug-resistant tuberculosis patients.

Patients and Methods

A total of 228 drug-resistant tuberculosis patients in selected hospitals in Oromia region, Ethiopia, were included in this study. Descriptive statistics like median time to sputum smear and culture conversion were computed. Bivariate and multivariate Cox proportional hazard models were used to identify the independent predictors of time to culture conversion. The adjusted hazard ratio (AHR) with 95% confidence interval (CI) was used to report the strength of association. Statistical significance was declared at p <0.05.

Results

The median age of the study participants was 28 years with inter-quartile range of (IQR) of 22–32 years, and 60% of the patients were male. The median time to culture conversion was 61 days (IQR: 34–92 days). The proportion of sputum culture conversion at 2nd, 4th, and 6th months of treatment initiation was 47%, 82.5%, and 89%, respectively. The final adjusted multivariate Cox proportional hazard model revealed that patients with massive effusion on chest radiographic finding had a 60%-decreased culture conversion time (AHR: 0.4, 95% CI: 0.1–0.9). Patients with abnormalities without cavitations (AHR: 0.5, 95% CI: 0.2–0.9) and those with uninterpreted findings (AHR: 0.3 95% CI: 0.1–0.5) had delayed culture conversion time.

Conclusion

Chest radiographic findings such as massive effusion, abnormalities without cavitations, and uninterpreted findings were found to be predictors of time to sputum culture conversion. Patients with such characteristics have prolonged culture conversion time. Hence, they may need special attention during the treatment.

Time to sputum culture conversion and its associated factors among multidrug-resistant tuberculosis patients in Eastern Africa: A systematic review and meta-analysis

OBJECTIVE

This study aimed to consider the estimated time to multi-resistant tuberculosis culture conversion, and associated factors, in order to enhance evidence utilization in eastern Africa.

METHODS

We systematically identified available articles on multidrug-resistant tuberculosis culture conversion using PubMed, Scopus, Cochrane Library, Web of Science core collection, and Science Direct databases. A random-effects model was employed using the R 3.6.1 version and Stata/se 14 software.

RESULTS

Nine articles with a sample size of 2458 multidrug-resistant tuberculosis patients were included. The two-month culture conversion rate was 75.4%, with a median time of 61.2 days (interquartile range: 48.6-73.8). In the included studies, favorable treatment outcomes of MDR-TB patients were seen in 75% of the cases, while unfavorable treatment outcomes were seen in 18% (10% deaths, 7% defaulted, and 1% treatment failure) of the cases. The independent factor for delayed sputum culture conversion was body mass index below 18.5kg/m² (HR=3.1, 95% CI: 2.0, 6.7).

CONCLUSION

The median time to sputum culture conversion was 61.2 days, which is a reasonably short time. Body mass index was the identified associated factor leading to delayed culture conversion. Therefore, there is a need for awareness of how to improve the nutritional status of multidrug-resistant tuberculosis patients through appropriate nutritional supports.

Improved treatment outcome of multidrug-resistant tuberculosis with the use of a rapid molecular test to detect drug resistance in China

OBJECTIVES

Numerous studies investigate the advantages of rapid molecular drug susceptibility testing (DST) in comparison to phenotypic DST, but the clinical impact on treating multi/extensively drug resistant TB(M/XDR-TB) is less studied. Therefore, we examined how molecular DST testing may improve MDR-TB treatment management and outcome in Chinese settings.

METHODS

We performed a comparative study of patient cohorts before and after the implementation of molecular DST diagnosis with Genotype MTBDRsl/MTBDRplus assay in two Chinese hospitals. We collected clinical information including time to sputum culture conversion and final treatment outcome.

RESULTS

In total, 242 MDR-TB patients were studied including 114 before (pre-implementation group) and 128 after the implementation (post-implementation group) of molecular DST. Time to MDR-TB diagnosis was significantly reduced for patients in the post-implementation group, as compared to the pre-implementation group (median,16 vs 62 days; P < 0.001). Patients with early available molecular DST results had a more rapid culture conversion (aHR1.94 95% CI: 1.37-2.73; median,12 vs 24 months, respectively; P < 0.001) and higher rate of treatment success (68% vs 47%, P < 0.01).

CONCLUSIONS

The use of molecular DST in routine care for MDR-TB diagnosis as compared to phenotypic DST was associated with a decreased time to culture conversion and improved treatment outcome, highlighting its important clinical value.

Multidrug-resistant patients receiving treatment in Niger who are infected with M. tuberculosis Cameroon family convert faster in smear and culture than those with M. tuberculosis Ghana family

In this study, we analyzed the M. tuberculosis complex (MTBc) population structure among multidrug-resistant TB (MDR-TB) patients in Niger and tested whether the Cameroon family displayed a slower response to MDR-TB treatment. We genotyped baseline clinical isolates that had been collected from pulmonary MDR-TB patients recruited consecutively between 2008 and 2016 in Niger. Spoligotyping was used to analyze the genetic diversity of mycobacterial lineages, and Kaplan Meier's analysis to compare treatment outcomes. A total of 222 MTBc isolates were genotyped; 204 (91,9%) were identified as the Euro-American L4 lineage, with the Ghana family (106, 47,4%) and the Cameroon family (63, 28,4%) being predominant. Patients infected by Cameroon family isolates 61(96,8%) showed faster conversion (log-rank p < 0.01) than those infected with Ghana family isolates (91,5%), and were more likely to experience favorable outcome (adjusted odds ratio [aOR] 4.4; 95%CI 1.1-17.9]; p = 0.015). We found no association between MTBc families and second-line drug resistance profiles (p > 0.05). Our findings show that MDR-TB in Niger is caused by major spoligotypes of the Euro-American L4; with more rapid smear and culture conversion in patients infected with the Cameroon family. These first insights may alert clinicians that slow conversion may be associated with the type of infecting strain.

Assessment of multidrug-resistant tuberculosis (MDR-TB) treatment outcomes in Sudan; findings and implications

Background: Multidrug-resistant tuberculosis (MDR-TB) has a socioeconomic impact and threatens global public health. We assessed treatment outcomes of MDR-TB and predictors of poor treatment outcomes in Sudan given current high prevalence rates.Methods: Combined retrospective and prospective cohort study at Abu-Anga hospital (TB specialized hospital in Sudan). All patients with MDR-TB between 2013 and 2017 were targeted.Results: A total of 156 patients were recruited as having good records, 117 (75%) were male, and 152 (97.4%) had pulmonary TB. Patients were followed for a median of 18 months and a total of 2108 person-months. The overall success rate was 63.5% and the mortality rate was 14.1%. Rural residency (P < 0.05) and relapsing on previous treatments (P < 0.05) were determinants of time to poor MDR-TB treatment outcomes.Conclusion: Overall, more attention needs to be given to special MDR-TB groups that are highly susceptible to poor outcomes, i.e. rural patients. As a result, it is highly recommended to maintain total coverage of medicines for all MDR-TB patients for the entire period of treatment in Sudan. It is also recommended to instigate more treatment centers in rural areas in Sudan together with programs to enhance adherence to treatments including patient counseling to improve future outcomes.

Intensive phase treatment outcome and associated factors among patients treated for multi drug resistant tuberculosis in Ethiopia: a retrospective cohort study

BACKGROUND

Multi-drug resistant Tuberculosis (MDR-TB) is a strain of Mycobacterium tuberculosis that is resistant to at least Rifampicin and Isoniazid drugs. The treatment success rate for MDR-TB cases is lower than for drug susceptible TB. Globally only 55% of MDR-TB patients were successfully treated. Monitoring the early treatment outcome and better understanding of the specific reasons for early unfavorable and unknown treatment outcome is crucial for preventing the emergence of further drug-resistant tuberculosis. However, this information is scarce in Ethiopia. Therefore, this study aimed to determine the intensive phase treatment outcome and contributing factors among patients treated for MDR-TB in Ethiopia.

METHODS

A 6 year retrospective cohort record review was conducted in fourteen TICs all over the country. The records of 751 MDR-TB patients were randomly selected using simple random sampling technique. Data were collected using a pre-tested and structured checklist. Multivariable multinomial logistic regression was undertaken to identify the contributing factors.

RESULTS

At the end of the intensive phase, 17.3% of MDR-TB patients had an unfavorable treatment outcome, while 16.8% had an unknown outcome with the remaining having a favorable outcome. The median duration of the intensive phase was 9.0 months (IQR 8.04-10.54). Having an unfavorable intensive phase treatment outcome was found significantly more common among older age [ARRR = 1.047, 95% CI (1.024, 1.072)] and those with a history of hypokalemia [ARRR = 0.512, 95% CI (0.280, 0.939)]. Having an unknown intensive phase treatment outcome was found to be more common among those treated under the ambulatory care [ARRR = 3.2, 95% CI (1.6, 6.2)], rural dwellers [ARRR = 0.370, 95% CI (0.199, 0.66)], those without a treatment supporter [ARRR = 0.022, 95% CI (0.002, 0.231)], and those with resistance to a limited number of drugs.

CONCLUSION

We observed a higher rate of unfavorable and unknown treatment outcome in this study. To improve favorable treatment outcome more emphasis should be given to conducting all scheduled laboratory monitoring tests, assignment of treatment supporters for each patient and ensuring complete recording and reporting which could be enhanced by quarterly cohort review. Older aged and rural patients need special attention. Furthermore, the sample referral network should be strengthened.

Predictors of time to sputum culture conversion in multi-drug-resistant tuberculosis and extensively drug-resistant tuberculosis in patients at Tshepong-Klerksdorp Hospital

Setting

Klerksdorp-Tshepong Hospital Complex MDR-TB Unit, North-West Province, South Africa.

Background

To determine the time to sputum culture conversion (TTSCC) and factors predictive of TTSCC in patients with multi-drug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) in the North-West Province.

Methods

A retrospective cohort study, abstracting patient demographic and clinical data, laboratory results, dates of sputum testing and sputum culture conversion results, from medical records of 526 MDR-TB and 47 XDR-TB patients started on TB treatment between 01 January 2012 and 31 December 2014. Predictors of TTSCC were determined by Cox proportional hazards regression.

Results

The median age was 38 years (interquartile range 31–47) with 64% being male. Overall, 79% (449) were Human Immunodeficiency Virus (HIV)-infected. The median TTSCC was 56.5 days and 162.5 days for MDR-TB and XDR-TB patients, respectively. In the multivariate analysis, age [hazard ratio (HR): 0.89, 95% confidence interval (CI): 0.96–0.99], being underweight (HR: 0.631.61, 95% CI: 0.451.03–0.882.51), Acid Fast Bacilli (AFB) positivity (HR: 0.72, 95 % CI: 0.51–1.01) and having XDR-TB (HR: 0.36. 95% CI: 0.19–0.69) were predictive of longer TTSCC.

Conclusion

Predictors of TTSC allow for MDR-TB- and XDR-TB-diagnosed patients to be identified early for effective management. Those with risk factors for delayed sputum culture conversion which are being underweight and having XDR-TB should be monitored carefully during treatment so that they can achieve sputum culture conversion early.

Increasing Number and Volume of Cavitary Lesions on Chest Computed Tomography Are Associated With Prolonged Time to Culture Conversion in Pulmonary Tuberculosis

Background

Cavitary lesions (CLs) primarily identified by chest x-ray (CXR) have been associated with worse clinical outcomes among patients with pulmonary tuberculosis (PTB). Chest computed tomography (CT), which has better resolution and increased sensitivity to detect lung abnormalities, has been understudied in PTB patients. We compared detection of CLs by CT and CXR and assessed their association with time to sputum culture conversion (tSCC).

Methods

This was a retrospective cohort study of 141 PTB patients who underwent CT. We used multivariate Cox proportional hazards models to evaluate the association between CLs on CXR and the number and single largest volume of CLs on CT with tSCC.

Results

Thirty (21%) and 75 (53%) patients had CLs on CXR and CT, respectively. CT detected cavities in an additional 44 patients (31%) compared with CXR. After multivariable adjustment, we observed a negative association between CLs and tSCC, with an adjusted hazard ratio (aHR) of 0.56 (95% confidence interval [CI], 0.32 to 0.97) for single CLs and 0.31 (95% CI, 0.16 to 0.60) for multiple CLs present on CT. Patients with a CL volume ≥25 mL had a prolonged tSCC (aHR, 0.39; 95% CI, 0.21 to 0.72). CLs on CXR were not associated with increased tSCC after multivariable adjustment.

Conclusions

CT detected a larger number of cavities in patients with PTB relative to CXR. We observed an association between increasing number and volume of CLs on CT and delayed tSCC independent of sputum microscopy result. Our findings highlight a potential role for CT in the clinical and research setting as a tool to risk-stratify patients with PTB.

Therapeutic effects of recombinant human interleukin 2 as adjunctive immunotherapy against tuberculosis: A systematic review and meta-analysis

Background

Interleukin 2 (IL-2) is a cytokine secreted by activated T cells. Studies exploring recombinant human interleukin 2 (rhuIL-2) as an adjunctive immunotherapeutic agent to treat tuberculosis (TB) have shown variable results; however, the true therapeutic efficacy of rhuIL-2 administration in TB patients has not been determined.

Methods

A systematic review to identify publications exploring the association between rhuIL-2-based immunotherapy for TB and outcomes (sputum culture conversion, sputum smear conversion, radiographic changes, and leukocyte phenotype changes) in patients with pulmonary TB published before June 8, 2018 was performed. Data were extracted and analyzed by two investigators independently.

Results

A total of 2,272 records were screened. Four randomized controlled trials (RCTs) comprising 656 pulmonary TB patients were finally included. The rhuIL-2 treatment could significantly improve the sputum culture conversion of TB (RR, 1.18; 95%CI: 1.03–1.36; I² < 0.01; P = 0.019) after at least 3 months of anti-TB therapy and the sputum smear conversion of TB during anti-TB therapy. Treating multidrug-resistant tuberculosis (MDR-TB) with rhuIL-2 could improve the sputum culture conversion (RR, 1.28; 95%CI: 1.05–1.57; I² < 0.01; P = 0.016) and smear conversion (RR, 1.28; 95%CI: 1.09–1.51; I² < 0.01; P = 0.003) at the end of anti-TB treatment. Meanwhile, rhuIL-2-based adjunctive immunotherapy could expand the proliferation and conversion of CD4⁺ and natural killer (NK) cells. Three of the included studies suggested that radiographic changes could not be improved by the use of rhuIL-2 as adjunctive immunotherapy. Publication bias did not exist.

Conclusions

Based on this first meta-analysis, rhuIL-2-based adjunctive immunotherapy appears to expand the proliferation and conversion of CD4⁺ and NK cells, as well as improve the sputum culture (at 3 months and later) and smear conversion of TB patients.

Time to sputum smear and culture conversions in multidrug resistant tuberculosis at University of Gondar Hospital, Northwest Ethiopia

Background

Sputum smear and culture conversions are an important indicator of treatment efficacy and help to determine treatment duration in multidrug resistant tuberculosis (MDR-TB) patients. There are no published studies of sputum smear and culture conversion of MDR-TB patients in Ethiopia. The objective of this study is to evaluate and compare time to initial sputum smear and culture conversion and to identify factors influencing time to culture conversion.

Methods

A retrospective cohort study was conducted among all culture positive and rifampicin mono resistant (RR) or MDR-TB patients from September 2011 to August 2016 at University of Gondar Hospital. Sputum cultures were collected monthly and conversion was defined as two consecutive negative cultures taken at least 30 days apart. Data were entered using EpiData and exported to SPSS software for analysis. Cox proportional hazard model was used to determine the predictor variables for culture conversion.

Results

Overall, 85.5% (201/235) of the patients converted their cultures in a median of 72 days (inter-quartile range: 44–123). More than half (61.7%) of patients achieved culture conversion within three months. The median time for sputum smear conversion was 54 days (inter-quartile range: 31–72). The median time to culture conversion among HIV positive patients was significantly shorter at 67 days (95% CI, 55.4–78.6) compared to HIV negative patients, 77 days (95% CI, 63.9–90, p = 0.005). Independent predictors of significantly longer time to sputum culture conversion were underweight (aHR = 0.71, 95% CI, 0.52–0.97), HIV negative (aHR = 0.66, 95% CI, 0.47–0.94) and treatment regimen composition (aHR = 0.57, 95% CI, 0.37–0.88). Significantly higher rate of culture conversion was observed in 2015 (aHR = 1.86, 95% CI, 1.1–3.14) and in 2016 (aHR = 3.7, 95% CI, 1.88–7.35) years of treatment compared to 2011.

Conclusions

Majority of patients achieved sputum culture conversion within three months and smear conversion within two months. Patients with identified risk factors were associated with delayed culture conversion. These factors should be considered during management of MDR-TB patients.

Time to sputum culture conversion and its determinants among Multi-drug resistant Tuberculosis patients at public hospitals of the Amhara Regional State: A multicenter retrospective follow up study

Background

In Ethiopia, Multi-drug resistant Tuberculosis (MDR-TB) is one of the major public health problems that need great attention. Time to sputum culture conversion is often used as an early predictive value for the final treatment outcome. Although guidelines for MDR-TB are frequently designed, medication freely provided, and centers for treatment duly expanded, studies on time to sputum culture conversion have been very limited in Ethiopia. This study was aimed at determining the time to sputum culture conversion and the determinants among MDR-TB patients at public Hospitals of the Amhara Regional State.

Methods

A retrospective follow up study was conducted between September 2010 and December 2016. Three hundred ninety two MDR-TB patients were included in the study. Parametric frailty models were fitted and Cox Snell residual was used for goodness of fit, which the Akaike’s information criteria was used for model selection. Adjusted hazard ratio (AHR) with a 95% confidence interval (CI) was reported to show the strength of association.

Result

Out of the 392 participants, sputum culture changed for 340(86.7%) during the follow up period. The median culture conversion time in this study was 65 (60–70 days). Alcohol drinking (AHR = 3.79, 95%CI = 1.65–8.68), sputum smear grading +2 (AHR = 0.39, 95%CI 0.19–0.79), smear grading +3 (AHR = 0.30, CI = 0.14–064), cavitations (AHR = 0.36, 95%CI = 0.19–0.68), and consolidation (AHR = 0.29, CI = 0.13–0.69) were the determinants of time to sputum culture conversion.

Conclusion

In this study, time to sputum culture was rapid as compared to 4 months WHO recommendation. Alcohol drinking, sputum smear grading, cavitations and consolidations were found to be the determinants of time to sputum culture conversion. Therefore, providing a special attention to patients who had baseline radiological finding is recommended, high bacillary load and patients with a history of alcohol intake at baseline should be given priority.

Factors affecting time to sputum culture conversion and treatment outcome of patients with multidrug-resistant tuberculosis in China

BACKGROUND

Few prospective cohort studies, none in China, have investigated the relationship between treatment outcomes of multidrug-resistant tuberculosis (MDR-TB) patients and sputum culture conversion. Factors affecting the time of the culture conversion throughout the whole course of the treatment have rarely been investigated.

METHODS

This study was performed in four cities in Jiangsu province, China. MDR-TB patients were consecutively enrolled between December 2011 and March 2014. Rates of sputum culture conversion were calculated and Cox proportional-hazards model was performed. Factors contributing to sputum culture conversion were investigated.

RESULTS

In all, 139 MDR-TB patients with treatment outcomes were enrolled. Median time to culture conversion among those who converted was 91.5 days (interquartile range, 34.0-110.8 days). After multivariable analysis, smoking (HR = 0.44; 95% CI: 0.23-0.83), drinking (HR = 0.41; 95% CI: 0.21-0.81), ofloxacin resistance (HR = 0.43; 95% CI: 0.24-0.76) and sputum smear grade > 1 (HR = 0.51; 95% CI: 0.31-0.83) were less likely to have culture conversion.

CONCLUSIONS

MDR-TB patients who smoke, drink, have ofloxacin resistance, or a high smear grade are less likely to respond to treatment and should be meticulously followed up.

Radiological signs associated with pulmonary multi-drug resistant tuberculosis: an analysis of published evidences

Background

Despite that confirmative diagnosis of pulmonary drug-sensitive tuberculosis (DS-TB) and multidrug resistant tuberculosis (MDR-TB) is determined by microbiological testing, early suspicions of MDR-TB by chest imaging are highly desirable in order to guide diagnostic process. We aim to perform an analysis of currently available literatures on radiological signs associated with pulmonary MDR-TB.

Methods

A literature search was performed using PubMed on January 29, 2018. The search words combination was "((extensive* drug resistant tuberculosis) OR (multidrug-resistant tuberculosis)) AND (CT or radiograph or imaging or X-ray or computed tomography)". We analyzed English language articles reported sufficient information of radiological signs of DS-TB vs. MDR-TB.

Results

Seventeen articles were found to be sufficiently relevant and included for analysis. The reported pulmonary MDR-TB cases were grouped into four categories: (I) previously treated (or 'secondary', or 'acquired') MDR-TB in HIV negative (-) adults; (II) new (or 'primary') MDR-TB in HIV(-) adults; (III) MDR-TB in HIV positive (+) adults; and (IV) MDR-TB in child patients. The common radiological findings of pulmonary MDR-TB included centrilobular small nodules, branching linear and nodular opacities (tree-in-bud sign), patchy or lobular areas of consolidation, cavitation, and bronchiectasis. While overall MDR-TB cases tended to have more extensive disease, more likely to be bilateral, to have pleural involvement, to have bronchiectasis, and to have lung volume loss; these signs alone were not sufficient for differential diagnosis of MDR-TB. Current literatures suggest that the radiological sign which may offer good specificity for pulmonary MDR-TB diagnosis, though maybe at the cost of low sensitivity, would be thick-walled multiple cavities, particularly if the cavity number is ≥3. For adult HIV(-) patients, new MDR-TB appear to show similar prevalence of cavity lesion, which was estimated to be around 70%, compared with previously treated MDR-TB.

Conclusions

Thick-walled multiple cavity lesions present the most promising radiological sign for MDR-TB diagnosis. For future studies cavity lesion characteristics should be quantified in details.

Comparison of Sputum-Culture Conversion for Mycobacterium bovis and M. tuberculosis

Current US guidelines recommend longer treatment for tuberculosis (TB) caused by pyrazinamide-resistant organisms (e.g., Mycobacterium bovis) than for M. tuberculosis TB. We compared treatment response times for patients with M. bovis TB and M. tuberculosis TB reported in the United States during 2006–2013. We included culture-positive, pulmonary TB patients with genotyping results who received standard 4-drug treatment at the time of diagnosis. Time to sputum-culture conversion was defined as time between treatment start date and date of first consistently culture-negative sputum. We analyzed 297 case-patients with M. bovis TB and 30,848 case-patients with M. tuberculosis TB. After 2 months of treatment, 71% of M. bovis and 65% of M. tuberculosis TB patients showed conversion of sputum cultures to negative. Likelihood of culture conversion was higher for M. bovis than for M. tuberculosis, even after controlling for treatment administration type, sex, and a composite indicator of bacillary burden.

Sputum bacteriology conversion and treatment outcome of patients with multidrug-resistant tuberculosis

Purpose

Multidrug-resistant tuberculosis (MDR-TB) requires long-term treatment, has a high fatality rate, and constitutes a global threat. Earlier detection of treatment failure is required to predict therapeutic efficacy.

Patients and methods

We enrolled MDR-TB patients consecutively from January 2011 through December 2012 in Lianyungang, China. Sputum smear microscopy tests and sputum cultures were performed once a month for the first 6 months following initiation of antituberculosis treatment and once every 2 months thereafter until the end of therapy. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) were used with a 95% CI to estimate the role of sputum bacteriology conversion in predicting treatment outcomes.

Results

Among the 92 MDR-TB patients enrolled in this study, 40.2% had poor treatment outcomes. The median initial sputum bacteriology conversion time was 1 month. Patients having 2-month sputum smear conversions (adjusted odds ratio [OR]: 7.19, 95% CI: 2.60–19.84) or culture conversions (adjusted OR: 2.88, 95% CI: 1.11–7.45) were more likely to experience good outcomes. The sensitivity and specificity obtained when using two-month sputum smear conversions to predict treatment outcomes were 67.6% (95% CI: 50.2–82.0) and 76.4% (95% CI: 63.0–86.8), respectively. The sensitivity and specificity obtained when using 2-month culture conversions to predict treatment outcomes were 48.6% (95% CI: 32.0–65.6) and 74.5% (95% CI: 61.0–85.3), respectively. The AUC for two-month smear conversions was 0.72 (95% CI: 0.62–0.81), significantly higher than that obtained for 2-month culture conversions (0.62, 95% CI: 0.52–0.72) (χ² = 4.18, P = 0.041).

Conclusion

The prognoses of MDR-TB patients displaying persistent sputum positivity were inferior to those for whom sputum bacteriology conversion was observed. Thus, sputum smear conversion results obtained 2 months after treatment initiation may provide a potential means for predicting MDR-TB treatment outcomes.

Applying tuberculosis management time to measure the tuberculosis infectious pool at a local level in Ethiopia

Background

Measuring the size of the infectious pool of tuberculosis (TB) is essential to understand the burden and monitor trends of TB control program performance. This study applied the concept of TB management time to estimate and compare the size of the TB infectious pool between 2009 and 2014 in West Gojjam Zone of Amhara Region, Ethiopia.

Methods

New sputum smear-positive and smear-negative pulmonary TB (PTB) and retreatment cases who attended 30 randomly selected public health facilities in West Gojjam Zone from October 2013 to October 2014 were consecutively enrolled in the study. In order to determine the infectious period, the TB management time (number of days from the onset of cough until start of anti-TB treatment) was computed for each patient category. The number of undiagnosed TB cases was estimated and hence the TB management time for the undiagnosed category was calculated. The total size of the TB infectious pool during the study period for the study zone was estimated as the annual number of infectious person days.

Results

New smear-positive and smear-negative PTB cases contributed 25,050 and 12,931 infectious person days per year to the TB infectious pool, respectively. The retreatment and presently undiagnosed cases contributed 8840 and 34,310 infectious person days per year, respectively. The total size of the TB infectious pool in West Gojjam Zone during the study period was estimated at 81,131 infectious person days per year or 3405 infectious person days per 100,000 population per year. Compared to a similar study done in 2009 in the study area, the current study showed reduction of the TB infectious pool by 244,279 infectious person days.

Conclusions

TB management time is a simple and practical tool that may help to estimate and compare the changes in the size of the TB infectious pool at local level. It may also be used as an indicator to monitor the changes in TB control program performance.

Electronic supplementary material

The online version of this article (10.1186/s40249-017-0371-6) contains supplementary material, which is available to authorized users.

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.

Association between Body Mass Index and Sputum Culture Conversion among South Korean Patients with Multidrug Resistant Tuberculosis in a Tuberculosis Referral Hospital

Background

Multidrug-resistant tuberculosis (MDR-TB) is an important global health problem. Furthermore, the time to identify a positive sputum culture is an important risk factor for the spread of tuberculosis, and several factors can predict a prolonged time to culture conversion. Moreover, the relationship between poor nutritional status and infectious disease is clearly established. Therefore, the present study aimed to investigate the association between body mass index (BMI) and sputum culture conversion within 3 months among patients with MDR-TB.

Materials and Methods

We retrospectively evaluated 218 patients with MDR-TB who were treated at a large tuberculosis referral hospital in South Korea between January 2005 and December 2010. The outcome of interest was defined as sputum culture conversion within 3 months, and we analyzed the association between BMI and this outcome.

Results

Among the 218 patients, 53 patients (24.3%) had a low BMI (<18.5 kg/m²). In the multivariate Cox proportional-hazards regression analysis, failure to achieve sputum culture conversion within 3 months was independently associated with having a low BMI (hazard ratio [HR]: 1.741, 95% confidence interval [CI]: 1.006–3.013; P = 0.047) and a positive sputum smear at the initiation of therapy (HR: 8.440, 95% CI: 1.146–62.138, P = 0.036).

Conclusion

Low BMI (<18.5 kg/m²) was an independent risk factor for failure to achieve sputum culture conversion within 3 months among patients with MDR-TB.

Clinical management of adults and children with multidrug-resistant and extensively drug-resistant tuberculosis

BACKGROUND

Globally there is a burgeoning epidemic of drug monoresistant tuberculosis (TB), multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Almost 20% of all TB strains worldwide are resistant to at least one major TB drug, including isoniazid. In several parts of the world there is an increasing incidence of MDR-TB, and alarmingly, almost a third of MDR-TB cases globally are resistant to either a fluoroquinolone or aminoglycoside. This trend cannot be ignored because drug-resistant TB is associated with greater morbidity compared to drug-susceptible TB, accounts for almost 25% of global TB mortality, is extremely costly to treat, consumes substantial portions of budgets allocated to national TB programmes in TB-endemic countries and is a major threat to healthcare workers, who are already in short supply in resource-poor settings. Even more worrying is the growing epidemic of resistance beyond XDR-TB, including resistance to newer drugs such as bedaquiline and delamanid, as well as the increasing prevalence of programmatically incurable TB in countries like South Africa, Russia, India and China. These developments threaten to reverse the gains already made against TB.

SOURCES

Articles related to MDR-TB and XDR-TB found on PubMed in all languages up to September 2016, published reviews, and files of the authors.

AIM AND CONTENT

To review the clinical management of adults and children with MDR- and XDR-TB with a particular emphasis on the utility of newer and repurposed drugs such as linezolid, bedaquiline and delamanid, as well as management of MDR- and XDR-TB in special situations such as in HIV-infected persons and in children.

IMPLICATIONS

This review informs on the prevention, diagnosis, and clinical management of MDR-TB and XDR-TB.

Tradeoffs in Introduction Policies for the Anti-Tuberculosis Drug Bedaquiline: A Model-Based Analysis

BACKGROUND

New drugs for the treatment of tuberculosis (TB) are becoming available for the first time in over 40 y. Optimal strategies for introducing these drugs have not yet been established. The objective of this study was to compare different strategies for introducing the new TB drug bedaquiline based on patients' resistance patterns.

METHODS AND FINDINGS

We created a Markov decision model to follow a hypothetical cohort of multidrug-resistant (MDR) TB patients under different bedaquiline use strategies. The explored strategies included making bedaquiline available to all patients with MDR TB, restricting bedaquiline usage to patients with MDR plus additional resistance and withholding bedaquiline introduction completely. We compared these strategies according to life expectancy, risks of acquired resistance, and the expected number and health outcomes of secondary cases. For our simulated cohort, the mean (2.5th, 97.5th percentile) life expectancy from time of initiation of MDR TB treatment at age 30 was 36.0 y (33.5, 38.7) assuming all patients with MDR TB received bedaquiline, 35.1 y (34.4, 35.8) assuming patients with pre-extensively drug-resistant (PreXDR) and extensively drug-resistant (XDR) TB received bedaquiline, and 34.9 y (34.6, 35.2) assuming only patients with XDR TB received bedaquiline. Although providing bedaquiline to all MDR patients resulted in the highest life expectancy for our initial cohort averaged across all parameter sets, for parameter sets in which bedaquiline conferred high risks of added mortality and only small reductions in median time to culture conversion, the optimal strategy would be to withhold use even from patients with the most extensive resistance. Across all parameter sets, the most liberal bedaquiline use strategies consistently increased the risk of bedaquiline resistance but decreased the risk of resistance to other MDR drugs. In almost all cases, more liberal bedaquiline use strategies reduced the expected number of secondary cases and resulting life years lost. The generalizability of our results is limited by the lack of available data about drug effects among individuals with HIV co-infection, drug interactions, and other sources of heterogeneity, as well as changing recommendations for MDR TB treatment.

CONCLUSIONS

If mortality benefits can be empirically verified, our results provide support for expanding bedaquiline access to all patients with MDR TB. Such expansion could improve patients' health, protect background MDR TB drugs, and decrease transmission, but would likely result in greater resistance to bedaquiline.

Clinical Features and Treatment Outcomes of Patients with Drug-Resistant and Drug-Sensitive Tuberculosis: A Historical Cohort Study in Porto Alegre, Brazil

Purpose

To evaluate the clinical features and treatment outcomes of patients with pulmonary tuberculosis, stratified by level of drug resistance.

Methods

This was a historical cohort study based on data from the II National Anti-Tuberculosis Drug Resistance Survey (2006–2007) collected at eight participating health care facilities in Porto Alegre, southern Brazil. The cohort was followed for 3 years after the start of treatment.

Results

Of 299 cases of smear-positive pulmonary tuberculosis included in the study, 216 (72.2%) were diagnosed at five public primary health care units and 83 (27.8%) at three public hospitals. Among these cases, the prevalence of drug-resistant tuberculosis was 14.4%, and that of multidrug-resistant tuberculosis was 4.7%. Overall, 32.0% of drug-resistant and 2.0% of multidrug-resistant cases occurred in previously treated patients. The most common comorbidity in the sample was HIV infection (26.2%). There was no association between drug-resistant or multidrug-resistant tuberculosis and sociodemographic variables. Cure was achieved in 66.7% of patients, and the default rate was 21.2%. The 2-month sputum conversion rate was 34.2%, and the relapse rate was 16.9%. Patients with drug-resistant tuberculosis had lower rates of cure (45.2%) and 2-month sputum conversion (25%), as well as a higher relapse rate (30.7%).

Conclusion

These results highlight the urgent need for a more effective TB control program in this geographical setting, with a major emphasis on treatment of drug-resistant and multidrug-resistant tuberculosis.

Risk factors for tuberculosis smear non-conversion in Eden district, Western Cape, South Africa, 2007-2013: a retrospective cohort study

Background

Tuberculosis (TB) continues to be a major global health problem. While progress has been made to improve TB cure rates, South Africa’s 76 % smear-positive pulmonary TB (PTB) case cure rate remains below the WHO target of 85 %. We report on the trends of TB smear non-conversion and their predictors at the end of an intensive phase of treatment, and how this impacted on treatment outcomes of smear-positive PTB cases in Eden District, Western Cape Province, South Africa.

Methods

Routinely collected, retrospective data of smear-positive PTB cases from the electronic TB register in Eden District between 2007 and 2013 was extracted. Non-conversion was defined as persistent sputum smear-positive PTB cases at the end of the two or three month intensive phase of treatment. Chi-square test for linear trend and simple linear regression analysis were used to analyse the change in percentages and slope of TB smear non-conversion rates over time. Risk factors for TB non-conversion, and their impact on treatment outcomes, were evaluated using logistic regression models.

Results

Of 12,742 total smear-positive PTB cases included in our study, 12.8 % (n = 1627) did not sputum smear convert; 13.3 % (1411 of 10,574) of new cases and 9.9 % (216 of 2168) of re-treatment cases. Although not statistically significant in either new or re-treatment cases, between 2007 and 2013, smear non-conversion decreased from 16.4 to 12.7 % (slope = −0.60; 95 % CI: −1.49 to 0.29; p = 0.142) in new cases, and from 11.3 to 10.8 % in re-treatment cases (slope = −0.29; 95 % CI: −1.06 to 0.48; p = 0.376). Male gender, HIV co-infection and a >2+ acid fast bacilli (AFB) smear grading at the start of TB treatment were independent risk factors for non-conversion (p < 0.001). Age was a risk factor for non-conversion in new cases, but not for re-treatment cases. Non-conversion was also associated with unsuccessful treatment outcomes (p < 0.01), including treatment default and treatment failure.

Conclusions

Smear-positive PTB cases, especially men and those with identified risk factors for non-conversion, should be closely monitored throughout their treatment period. The South African TB control program should invest in patient adherence counselling and education to mitigate TB non-conversion risk factors, and to improve conversion and TB cure rates.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1712-y) contains supplementary material, which is available to authorized users.

Convergence of a diabetes mellitus, protein energy malnutrition, and TB epidemic: the neglected elderly population

BACKGROUND

On a global scale, nearly two billion persons are infected with Mycobacterium tuberculosis. From this vast reservoir of latent tuberculosis (TB) infection, a substantial number will develop active TB during their lifetime, with some being able to transmit TB or Multi-drug- resistant (MDR) TB to others. There is clinical evidence pointing to a higher prevalence of infectious diseases including TB among individuals with Diabetes Mellitus (DM). Furthermore, ageing and diabetes mellitus may further aggravate protein-energy malnutrition (PEM), which in turn impairs T-lymphocyte mediated immunologic defenses, thereby increasing the risk of developing active TB and compromising TB treatment. This article aims to a) highlight synergistic mechanisms associated with immunosenescence, DM and PEM in relation to the development of active TB and b) identify nutritional, clinical and epidemiological research gaps.

METHODS

To explore the synergistic relationship between ageing, DM, tuberculosis and PEM, a comprehensive review was undertaken. The MEDLINE and the Google Scholar databases were searched for articles published from 1990 to March 2015, using different MESH keywords in various combinations.

RESULTS

Ageing and DM act synergistically to reduce levels of interferon gamma (IFN- γ), thereby increasing susceptibility to TB, for which cell mediated immunity (CMI) plays an instrumental role. These processes can set in motion a vicious nutritional cycle which can predispose to PEM, further impairing the CMI and consequently limiting host defenses. This ultimately transforms the latent TB infection into active disease. A clinical diagnostic algorithm and clinical guidelines need to be established for this population.

CONCLUSION

Given the increase in ageing population with DM and PEM, especially in resource-poor settings, these synergistic tripartite interactions must be examined if a burgeoning TB epidemic is to be averted. Implementation of a comprehensive, all-encompassing approach to curb transmission is clearly indicated. To this end, clinical, nutritional and epidemiological research gaps must be addressed without a delay.

High Systemic Exposure of Pyrazinoic Acid Has Limited Antituberculosis Activity in Murine and Rabbit Models of Tuberculosis

Pyrazinamide (PZA) is a prodrug requiring conversion to pyrazinoic acid (POA) by an amidase encoded by pncA for in vitro activity. Mutation of pncA is the most common cause of PZA resistance in clinical isolates. To determine whether the systemic delivery of POA or host-mediated conversion of PZA to POA could circumvent such resistance, we evaluated the efficacy of orally administered and host-derived POA in vivo Dose-ranging plasma and intrapulmonary POA pharmacokinetics and the efficacy of oral POA or PZA treatment against PZA-susceptible tuberculosis were determined in BALB/c and C3HeB/FeJ mice. The activity of host-derived POA was assessed in rabbits infected with a pncA-null mutant and treated with PZA. Median plasma POA values for the area under the concentration-time curve from 0 h to infinity (AUC0-∞) were 139 to 222 μg·h/ml and 178 to 287 μg·h/ml after doses of PZA and POA of 150 mg/kg of body weight, respectively, in mice. Epithelial lining fluid POA concentrations in infected mice were comparable after POA and PZA administration. In chronically infected BALB/c mice, PZA at 150 mg/kg reduced lung CFU counts by >2 log10 after 4 weeks. POA was effective only at 450 mg/kg, which reduced lung CFU counts by ∼0.7 log10 POA had no demonstrable bactericidal activity in C3HeB/FeJ mice, nor did PZA administered to rabbits infected with a PZA-resistant mutant. Oral POA administration and host-mediated conversion of PZA to POA producing plasma POA exposures comparable to PZA administration was significantly less effective than PZA. These results suggest that the intrabacillary delivery of POA and that producing higher POA concentrations at the site of infection will be more effective strategies for maximizing POA efficacy.

Diabetes Reduces the Rate of Sputum Culture Conversion in Patients With Newly Diagnosed Multidrug-Resistant Tuberculosis

Background.  Diabetes is a risk factor for active tuberculosis (TB), but little is known about the relationship between diabetes and multidrug-resistant (MDR) TB. We aimed to assess risk factors for primary MDR TB, including diabetes, and determine whether diabetes reduced the rate of sputum culture conversion among patients with MDR TB. Methods.  From 2011 to 2014, we conducted a cohort study at the National Center for Tuberculosis and Lung Diseases in Tbilisi, Georgia. Adult (≥35 years) patients with primary TB were eligible. Multidrug-resistant TB was defined as resistance to at least rifampicin and isoniazid. Patients with capillary glycosylated hemoglobin (HbA1c) ≥ 6.5% or previous diagnosis were defined to have diabetes. Polytomous regression was used to estimate the association of patient characteristics with drug resistance. Cox regression was used to compare rates of sputum culture conversion in patients with and without diabetes. Results.  Among 318 patients with TB, 268 had drug-susceptibility test (DST) results. Among patients with DST results, 19.4% (52 of 268) had primary MDR TB and 13.4% (36 of 268) had diabetes. In multivariable analyses, diabetes (adjusted odds ratio [aOR], 2.51; 95% confidence interval [CI], 1.00-6.31) and lower socioeconomic status (aOR, 3.51; 95% CI, 1.56-8.20) were associated with primary MDR TB. Among patients with primary MDR TB, 44 (84.6%) converted sputum cultures to negative. The rate of sputum culture conversion was lower among patients with diabetes (adjusted hazard ratio [aHR], 0.34; 95% CI, .13-.87) and among smokers (aHR, 0.16; 95% CI, .04-.61). Conclusions.  We found diabetes was associated with an increased risk of primary MDR TB; both diabetes and smoking were associated with a longer time to sputum culture conversion.

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.

Effect of drug resistance on negative conversion of sputum culture in patients with pulmonary tuberculosis

OBJECTIVE

Negative conversion of sputum culture is a useful marker for predicting treatment outcome and relapse of pulmonary tuberculosis (TB). The effect of drug resistance on negative conversion of sputum culture with treatment was evaluated in this study.

METHODS

A total of 535 patients with culture-proven pulmonary TB were classified into three groups: drug-susceptible (DS), other drug-resistant (ODR), and multidrug-resistant/extensively drug-resistant (MDR/XDR). Rates of conversion of sputum culture at 4, 8, and 12 weeks were compared.

RESULTS

At 4 weeks of treatment, the conversion rate in the DS group (52.7%) was higher than that in the ODR group (30.8%, p=0.003), but was not different compared with the MDR group (45.7%, p=0.427). At 8 weeks, the conversion rate in the DS group (76.3%) was higher than that in the ODR (63.5%, p=0.042) and MDR groups (60.0%, p=0.031). At 12 weeks, the conversion rate in the DS group (85.9%) tended to be higher than that in the MDR group (74.3%, p=0.062), but was not different from that in the ODR group (84.6%, p=0.796).

CONCLUSION

The pattern of resistance to anti-TB drugs affects culture conversion rates in the early phase of treatment and also prolongs the time to culture conversion.

Association between Regimen Composition and Treatment Response in Patients with Multidrug-Resistant Tuberculosis: A Prospective Cohort Study

BACKGROUND

For treating multidrug-resistant tuberculosis (MDR TB), the World Health Organization (WHO) recommends a regimen of at least four second-line drugs that are likely to be effective as well as pyrazinamide. WHO guidelines indicate only marginal benefit for regimens based directly on drug susceptibility testing (DST) results. Recent evidence from isolated cohorts suggests that regimens containing more drugs may be beneficial, and that DST results are predictive of regimen effectiveness. The objective of our study was to gain insight into how regimen design affects treatment response by analyzing the association between time to sputum culture conversion and both the number of potentially effective drugs included in a regimen and the DST results of the drugs in the regimen.

METHODS AND FINDINGS

We analyzed data from the Preserving Effective Tuberculosis Treatment Study (PETTS), a prospective observational study of 1,659 adults treated for MDR TB during 2005-2010 in nine countries: Estonia, Latvia, Peru, Philippines, Russian Federation, South Africa, South Korea, Thailand, and Taiwan. For all patients, monthly sputum samples were collected, and DST was performed on baseline isolates at the US Centers for Disease Control and Prevention. We included 1,137 patients in our analysis based on their having known baseline DST results for at least fluoroquinolones and second-line injectable drugs, and not having extensively drug-resistant TB. These patients were followed for a median of 20 mo (interquartile range 16-23 mo) after MDR TB treatment initiation. The primary outcome of interest was initial sputum culture conversion. We used Cox proportional hazards regression, stratifying by country to control for setting-associated confounders, and adjusting for the number of drugs to which patients' baseline isolates were resistant, baseline resistance pattern, previous treatment history, sputum smear result, and extent of disease on chest radiograph. In multivariable analysis, receiving an average of at least six potentially effective drugs (defined as drugs without a DST result indicating resistance) per day was associated with a 36% greater likelihood of sputum culture conversion than receiving an average of at least five but fewer than six potentially effective drugs per day (adjusted hazard ratio [aHR] 1.36, 95% CI 1.09-1.69). Inclusion of pyrazinamide (aHR 2.00, 95% CI 1.65-2.41) or more drugs to which baseline DST indicated susceptibility (aHR 1.65, 95% CI 1.48-1.84, per drug) in regimens was associated with greater increases in the likelihood of sputum culture conversion than including more drugs to which baseline DST indicated resistance (aHR 1.33, 95% CI 1.18-1.51, per drug). Including in the regimen more drugs for which DST was not performed was beneficial only if a minimum of three effective drugs was present in the regimen (aHR 1.39, 95% CI 1.09-1.76, per drug when three effective drugs present in regimen). The main limitation of this analysis is that it is based on observational data, not a randomized trial, and drug regimens varied across sites. However, PETTS was a uniquely large and rigorous observational study in terms of both the number of patients enrolled and the standardization of laboratory testing. Other limitations include the assumption of equivalent efficacy across drugs in a category, incomplete data on adherence, and the fact that the analysis considers only initial sputum culture conversion, not reversion or long-term relapse.

CONCLUSIONS

MDR TB regimens including more potentially effective drugs than the minimum of five currently recommended by WHO may encourage improved response to treatment in patients with MDR TB. Rapid access to high-quality DST results could facilitate the design of more effective individualized regimens. Randomized controlled trials are necessary to confirm whether individualized regimens with more than five drugs can indeed achieve better cure rates than current recommended regimens.

Sputum culture conversion as a prognostic marker for end-of-treatment outcome in patients with multidrug-resistant tuberculosis: a secondary analysis of data from two observational cohort studies

BACKGROUND

Sputum culture conversion is often used as an early microbiological endpoint in phase 2 clinical trials of tuberculosis treatment on the basis of its assumed predictive value for end-of-treatment outcome, particularly in patients with drug-susceptible tuberculosis. We aimed to assess the validity of sputum culture conversion on solid media at varying timepoints, and the time to conversion, as prognostic markers for end-of-treatment outcome in patients with multidrug-resistant (MDR) tuberculosis.

METHODS

We analysed data from two large cohort studies of patients with MDR tuberculosis. We defined sputum culture conversion as two or more consecutive negative cultures from sputum samples obtained at least 30 days apart. To estimate the association of 2 month and 6 month conversion with successful treatment outcome, we calculated odds ratios (ORs) and 95% CIs with random-effects multivariable logistic regression. We calculated predictive values with bivariate random-effects generalised linear mixed modelling.

FINDINGS

We assessed data for 1712 patients who had treatment success, treatment failure, or who died. Among patients with treatment success, median time to sputum culture conversion was significantly shorter than in those who had poor outcomes (2 months [IQR 1-3] vs 7 months [3 to ≥24]; log-rank p<0·0001). Furthermore, conversion status at 6 months (adjusted OR 14·07 [95% CI 10·05-19·71]) was significantly associated with treatment success compared with failure or death. Sputum culture conversion status at 2 months was significantly associated with treatment success only in patients who were HIV negative (adjusted OR 4·12 [95% CI 2·25-7·54]) or who had unknown HIV infection (3·59 [1·96-6·58]), but not in those who were HIV positive (0·38 [0·12-1·18]). Thus, the overall association of sputum culture conversion with a successful outcome was substantially greater at 6 months than at 2 months. 2 month conversion had low sensitivity (27·3% [95% confidence limit 16·6-41·4]) and high specificity (89·8% [82·3-94·4]) for prediction of treatment success. Conversely, 6 month sputum culture conversion status had high sensitivity (91·8% [85·9-95·4]), but moderate specificity (57·8% [42·5-71·6]). The maximum combined sensitivity and specificity for sputum culture conversion was reached between month 6 and month 10 of treatment.

INTERPRETATION

Time to sputum culture conversion, conversion status at 6 months, and conversion status at 2 months in patients without known HIV infection can be considered as proxy markers of end-of-treatment outcome in patients with MDR tuberculosis, although the overall association with treatment success is substantially stronger for 6 month than for 2 month conversion status. Investigators should consider these results regarding the validity of sputum culture conversion at various timepoints as an early predictor of treatment efficacy when designing phase 2 studies before investing substantial resources in large, long-term, phase 3 trials of new treatments for MDR tuberculosis.

FUNDING

US Agency for International Development, US Centers for Disease Control and Prevention, Division of Intramural Research of the US National Institute of Allergy and Infectious Diseases, Korea Centers for Disease Control and Prevention.

Time to culture conversion and regimen composition in multidrug-resistant tuberculosis treatment

Sputum cultures are an important tool in monitoring the response to tuberculosis treatment, especially in multidrug-resistant tuberculosis. There has, however, been little study of the effect of treatment regimen composition on culture conversion. Well-designed clinical trials of new anti-tuberculosis drugs require this information to establish optimized background regimens for comparison. We conducted a retrospective cohort study to assess whether the use of an aggressive multidrug-resistant tuberculosis regimen was associated with more rapid sputum culture conversion. We conducted Cox proportional-hazards analyses to examine the relationship between receipt of an aggressive regimen for the 14 prior consecutive days and sputum culture conversion. Sputum culture conversion was achieved in 519 (87.7%) of the 592 patients studied. Among patients who had sputum culture conversion, the median time to conversion was 59 days (IQR: 31–92). In 480 patients (92.5% of those with conversion), conversion occurred within the first six months of treatment. Exposure to an aggressive regimen was independently associated with sputum culture conversion during the first six months of treatment (HR: 1.36; 95% CI: 1.10, 1.69). Infection with human immunodeficiency virus (HR 3.36; 95% CI: 1.47, 7.72) and receiving less exposure to tuberculosis treatment prior to the individualized multidrug-resistant tuberculosis regimen (HR: 1.58; 95% CI: 1.28, 1.95) were also independently positively associated with conversion. Tachycardia (HR: 0.77; 95% CI: 0.61, 0.98) and respiratory difficulty (HR: 0.78; 95% CI: 0.62, 0.97) were independently associated with a lower rate of conversion. This study is the first demonstrating that the composition of the multidrug-resistant tuberculosis treatment regimen influences the time to culture conversion. These results support the use of an aggressive regimen as the optimized background regimen in trials of new anti-TB drugs.

Significant clinical impact of a rapid molecular diagnostic test (Genotype MTBDRplus assay) to detect multidrug-resistant tuberculosis

BACKGROUND

There are limited data on the clinical impact of rapid diagnostic tests to detect multidrug-resistant tuberculosis (MDR-TB). We sought to determine whether the use of a molecular diagnostic test to detect MDR-TB improves clinical outcomes.

METHODS

A quasi-experimental study was conducted to analyze the impact of the Genotype MTBDRplus assay on clinical outcomes among patients with culture-confirmed pulmonary MDR-TB. Patients received treatment at the National Center for Tuberculosis and Lung Diseases in Tbilisi, Georgia. Time to MDR-TB treatment initiation, culture conversion, and infection control measures were compared to a time period prior to the implementation of the molecular test.

RESULTS

Of 152 MDR-TB patients, 72 (47%) were from prior to and 80 (53%) following implementation of the MTBDRplus assay ("post-implementation group"). Patients in the post-implementation group initiated a second-line treatment regimen more rapidly than those in the pre-implementation group (18.2 vs 83.9 days, P < .01). Among patients admitted to a "drug-susceptible" tuberculosis ward, those from the post-implementation group spent significantly fewer days on the drug-susceptible ward compared to patients in the pre-implementation group (10.0 vs 58.3 days, P < .01). Among patients with 24 weeks follow-up (n = 119), those in the post-implementation group had a higher rate of culture conversion at 24 weeks (86% vs 63%, P < .01) and a more rapid rate of time to culture conversion (adjusted hazard ratio [aHR] 4.15, 95% confidence interval [CI], 2.5-6.9).

CONCLUSIONS

The implementation of a rapid molecular diagnostic test led to significant clinical improvements including reduced time to initiation of MDR-TB treatment, culture conversion, and improved infection control practices.

Diabetes mellitus, smoking status, and rate of sputum culture conversion in patients with multidrug-resistant tuberculosis: a cohort study from the country of Georgia

Introduction

Diabetes mellitus (DM) is a risk factor for active tuberculosis (TB) but little is known about the effect of DM on culture conversion among patients with multidrug-resistant (MDR)-TB. The primary aim was to estimate the association between DM and rate of TB sputum culture conversion. A secondary objective was to estimate the association between DM and the risk of poor treatment outcomes among patients with MDR-TB.

Materials and Methods

A cohort of all adult patients starting MDR-TB treatment in the country of Georgia between 2009–2011 was followed during second-line TB therapy. Cox proportional models were used to estimate the adjusted hazard rate of sputum culture conversion. Log-binomial regression models were used to estimate the cumulative risk of poor TB treatment outcome.

Results

Among 1,366 patients with sputum culture conversion information, 966 (70.7%) had culture conversion and the median time to conversion was 68 days (interquartile range 50–120). The rate of conversion was similar among patients with MDR-TB and DM (adjusted hazard ratio [aHR] 0.95, 95%CI 0.71–1.28) compared to patients with MDR-TB only. The rate of culture conversion was significantly less in patients that currently smoked (aHR 0.82, 95%CI 0.71–0.95), had low body mass index (aHR 0.71, 95%CI 0.59–0.84), second-line resistance (aHR 0.56, 95%CI 0.43–0.73), lung cavities (aHR 0.70, 95%CI 0.59–0.83) and with disseminated TB (aHR 0.75, 95%CI 0.62–0.90). The cumulative risk of poor treatment outcome was also similar among TB patients with and without DM (adjusted risk ratio [aRR] 1.03, 95%CI 0.93–1.14).

Conclusions

In adjusted analyses, DM did not impact culture conversion rates in a clinically meaningful way but smoking did.

Predictors of two months culture conversion in multidrug-resistant tuberculosis: findings from a retrospective cohort study

BACKGROUND

Various studies have reported culture conversion at two months as a predictor of successful treatment outcome in multidrug-resistant tuberculosis (MDR-TB).

OBJECTIVES

The present study was conducted with the aim to evaluate the rate and predictors of culture conversion at two months in MDR-TB patients.

METHODS

All confirmed pulmonary MDR-TB patients enrolled for treatment at Lady Reading Hospital Peshawar, Pakistan from 1 January to 31 December 2012 and met the inclusion criteria were reviewed retrospectively. Rate and predictors of culture conversion at two months were evaluated.

RESULTS

Eighty seven (53.4%) out of 163 patients achieved culture conversion at two months. In a multivariate analysis lung cavitation at baseline chest X-ray (P = 0.006, OR = 0.349), resistance to ofloxacin (P = 0.041, OR = 0.193) and streptomycin (P = 0.017, OR = 0.295) had statistically significant (P<0.05) negative association with culture conversion at two months.

CONCLUSION

A reasonable proportion of patients achieved culture conversion at two months. Factors negatively associated with culture conversion at two months can be easily identified either before diagnosis or early in the course of MDR-TB treatment. This may help in better care of individual patients by identifying them early and treating them vigorously.