First-line Drug Susceptibility Testing Research Articles

Evaluation of 3-year tuberculosis external quality assessment results of public health laboratories.

Background We aimed to evaluate the 3-year participation status of tuberculosis (TB) laboratories in public health laboratories (PHL) tuberculosis external quality assessment (EQA) and EQA results. Method During 2018-2020, PHLs participated in the EQA programme organized annually by the National Tuberculosis Reference Laboratory (NTRL). Five kinds of EQA samples were sent to the participating laboratories on three parameters, including microscopy, culture and phenotypic first-line drug susceptibility testing and they were asked to perform according to the standard protocol. The results were taken over by the Tuberculosis Laboratories Surveillance Network (TULSA) web system and analysed. Results A total of 24 PHLs participated in the EQA in 2018; 30 in 2019 and 23 in 2020. In terms of sensitivity, specificity, accuracy and reproducibility in microscopy, respectively, in 2018, 20 of the laboratories were 100%, 4 of them 80%, and in culture 16 of them were 100% and 2 of them 80%; in 2019, 28 of them were 100%, 2 of them 80%, and in culture 11 of them were 100%, 6 of them 80%, 1 of them 60%; in 2020, 20 of them were 100%, 3 of them 80%, and in culture 13 of them were 100% and 3 of them 80%. Conclusion It is beneficial for laboratories working on TB to participate in EQA in terms of evaluating the accuracy and reliability of the method used.

A rare case of isoniazid mono-resistant tuberculosis presenting as cardiac tamponade along with an anterior mediastinal mass in a 15-year-old immunocompetent patient.

A 15-year-old boy presented with a sudden onset of breathlessness for 7 days, gradual loss of weight of 17.6 lbs over the last month and progressive hoarseness of voice for 7 months. The contrast-enhanced computed tomography (CECT) scan revealed a heterogeneously enhancing lesion in the anterior mediastinum with multiple discrete lymph nodes in the cervical and mediastinal locations. The GeneXpert MTB/RIF assay performed on the CT-guided biopsy of the mass was negative, but the culture for Mycobacterium tuberculosis was positive at 7 weeks of incubation. There was a suboptimal radiological response after 6 months of treatment. First-line drug susceptibility testing (DST) performed by line probe assay (LPA) on the positive culture detected high-level resistance to isoniazid. The treatment was modified as per DST results to which the patient responded well.

Genotypic and phenotypic drug resistance patterns of Mycobacterium tuberculosis isolated from presumptive pulmonary tuberculosis patients in Ethiopia: A multicenter study.

The emergence of drug-resistant tuberculosis (DR-TB) has been a major obstacle to global tuberculosis control programs, especially in developing countries, including Ethiopia. This study investigated drug resistance patterns and associated mutations of Mycobacterium tuberculosis Complex (MTBC) isolates from the Amhara, Gambella, and Benishangul-Gumuz regions of Ethiopia. A cross-sectional study was conducted using 128 MTBC isolates obtained from patients with presumptive tuberculosis (TB). Phenotypic (BACTEC MGIT 960) and genotypic (MTBDRplus and MTBDRsl assays) methods were used for drug susceptibility testing. Data were entered into Epi-info and analyzed using SPSS version 25. Frequencies and proportions were determined to describe drug resistance levels and associated mutations. Of the 127 isolates recovered, 100 (78.7%) were susceptible to four first-line anti-TB drugs. Any drug resistance, polydrug resistance, and multi-drug resistance (MDR) were detected in 21.3% (27), 15.7% (20), and 15% (19) of the isolates, respectively, by phenotypic and/or genotypic methods. Mono-resistance was observed for Isoniazid (INH) (2, 1.6%) and Streptomycin (STR) (2, 1.6%). There were two genotypically discordant RIF-resistant cases and one INH-resistant case. One case of pre-extensively drug-resistant TB (pre-XDR-TB) and one case of extensively drug-resistant TB (XDR-TB) were identified. The most frequent gene mutations associated with INH and rifampicin (RIF) resistance were observed in the katG MUT1 (S315T1) (20, 76.9%) and rpoB (S531L) (10, 52.6%) genes, respectively. Two MDR-TB isolates were resistant to second-line drugs; one had a mutation in the gyrA MUT1 gene, and the other had missing gyrA WT1, gyrA WT3, and rrs WT1 genes without any mutation. The detection of a significant proportion of DR-TB cases in this study suggests that DR-TB is a major public health problem in Ethiopia. Thus, we recommend the early detection and treatment of DR-TB and universal full first-line drug-susceptibility testing in routine system.

Tuberculosis cases related to tertiary care cardiac center experiences in the last 10 years.

Tuberculosis (TB) is one of the oldest and deadliest infectious diseases known to affect human health, which is gaining renewed importance today. In our center, which is a tertiary research hospital, the data of patients hospitalized due to TB between 2011 and 2022 were retrospectively identified by searching the database. Six women (30.0%) and 14 men (70.0%) were included in the study. When analyzed by age grouping, four patients between the ages of 19 and 34 years (20.0%), five patients between the ages of 38 and 58 years (25.0%), five patients aged 61-69 years (25.0%), and six patients aged 70-81 years (30.0%). Radiographs showed cavitation in 9 (45.0%) patients, and 11 (55.0%) patients had no radiologic findings. The ARS results of the participants showed that there were 7 (35.0%) patients positive and 13 (65.0%) patients negative. When the TB culture variables of the participants were analyzed, it was found that there were 5 (25.0%) people with no growth and 15 (75.0%) people with growth. Concurrent diseases were noted in patients including 5 (25.0%) with organ transplantation, 3 (15.0%) with diabetes mellitus, 2 (%10) with cancer, and 2 (10%) with chronic renal failure according to the chart records. The distribution of cases was as follows: 19 (95.0%) pulmonary TB and 1 (5.0%) pleural TB. It was found that there were 5 (25.0%) people with a history of TBC and 15 people (75.0%) without a history of TBC. Moreover, drug susceptibility tests showed that 5 (25%) patients of the isolates were identified as multidrug resistant with first-line drug susceptibility testing. The study was not financially supported by any individual/organization, and the authors have no vested interests.

Detection of Mutations in pncA in Mycobacterium tuberculosis Clinical Isolates from Nepal in Association with Pyrazinamide Resistance.

Without the proper information on pyrazinamide (PZA) susceptibility of Mycobacterium tuberculosis (MTB), PZA is inappropriately recommended for the treatment of both susceptible and multidrug-resistant tuberculosis (MDR-TB) in Nepal. This study aimed to collect information regarding PZA susceptibility in MTB isolates from Nepal by analyzing pncA and its upstream regulatory region (URR). A total of 211 MTB isolates were included in this study. Sequence analysis of pncA and its URR was performed to assess PZA resistance. First-line drug susceptibility testing, spoligotyping, and sequence analysis of rpoB, katG, the inhA regulatory region, gyrA, gyrB, and rrs were performed to assess their association with pncA mutation. Sequencing results reveal that 125 (59.2%) isolates harbored alterations in pncA and its URR. A total of 57 different mutation types (46 reported and 11 novel) were scattered throughout the whole length of the pncA gene. Eighty-seven isolates (41.2%) harbored mutations in pncA, causing PZA resistance in MTB. There was a more significant association of pncA alterations in MDR/pre-extensively drug-resistant (Pre-XDR) TB than in mono-resistant/pan-susceptible TB (p < 0.005). This first report on the increasing level of PZA resistance in DR-TB in Nepal highlights the importance of PZA susceptibility testing before DR-TB treatment.

Genotypic and phenotypic drug-resistance detection and prevalence of heteroresistance in patients with isoniazid- and multidrug-resistant tuberculosis in Ethiopia

ObjectiveTo assess the agreement between genotypic and phenotypic methods for detecting drug resistance, and examine the prevalence of heteroresistance among isoniazid (INH)- and multidrug/rifampicin-resistant (MDR/RR) TB. MethodIn total, 127 Mycobacterium tuberculosis (Mtb) isolates, including 65 MDR/RR and 62 INH resistant, were used. First-line drug susceptibility testing (DST) was performed using the LJ method to determine the percentage of resistant bacteria. All drug-resistant isolates underwent testing with LPA. Heteroresistance was defined as simultaneous detection of wild-type and resistance-conferring mutations using LPA. ResultThe sensitivity of LPA (compared with LJ DST) was 96% for any INH-resistant TB and 94% for any RR TB. The prevalence of heteroresistance among the 123. Mtb isolates was 9.8%. The percentage of resistant bacteria ranged from 1% to 10% for heteroresistant TB. Rifampicin heteroresistance was detected in 1.6% of MDR TB patients. INH heteroresistance was detected in 1.6% and 16.7% of MDR and INH-resistant TB patients, respectively. The proportion of INH heteroresistance was significantly higher (p = 0.030) in persons living with HIV. ConclusionSome phenotypic drug resistances were not captured by LPA. The prevalence and percentage of resistant bacteria among heteroresistant TB highlight the importance of LPA for early detection of heteroresistant TB.

High degree of fluoroquinolone resistance among extrapulmonary tuberculosis patients at a tertiary care center in North India.

The treatment of drug-resistant tuberculosis (TB) involves various regimens. Among them, the most promising antibiotic regimens are fluoroquinolone (FQ) drugs. Drug susceptibility testing (DST) for FQs is not included as routine assessment for baseline TB diagnosis. Limited resources are available about FQ resistance among extrapulmonary TB (EPTB) cases. A total of 447 culture-positive specimens were subjected to DST for first-line anti-TB drugs (FLDs) and second-line anti-TB drugs. DST was performed using automated mycobacterium growth indicator tube-960 liquid culture techniques. The study was carried out during the period of April 2016 to March 2017. In addition, DST of FQs was also performed in FLD-sensitive strains. Mycobacterium tuberculosis was isolated from 447 specimens. Of the 447 culture-positive EPTB specimens, 54 were rifampicin-resistant (RR)/multidrug-resistant TB (MDR-TB) isolates, 45 isolates were resistant to any drug, and the remaining 348 were sensitive to FLDs. Monoresistance of FQs was observed in 20.4% (11/54) among RR/MDR-TB isolates and 4.3% (15/348) among FLD-sensitive isolates. The high degree of FQ resistance observed in EPTB specimens among drug-sensitive and MDR-TB isolates is alarming. This study reflects the need to expand culture and DST for EPTB cases and include FQs within first-line DST in such settings. Furthermore, there should be a rational use of FQs for the treatment of other diseases.

Second nationwide anti-tuberculosis drug resistance survey in Namibia

SETTING: Namibia ranks among the 30 high TB burden countries worldwide. Here, we report results of the second nationwide anti-TB drug resistance survey.OBJECTIVE: To assess the prevalence and trends of multidrug-resistant TB (MDR-TB) in Namibia.METHODS: From 2014 to 2015, patients with presumptive TB in all regions of Namibia had sputum subjected to mycobacterial culture and phenotypic drug susceptibility testing (DST) for rifampicin, isoniazid, ethambutol and streptomycin if positive on smear microscopy and/or Xpert MTB/RIF.RESULTS: Of the 4124 eligible for culture, 3279 (79.5%) had Mycobacterium tuberculosis isolated. 3126 (95%) had a first-line DST completed (2392 new patients, 699 previously treated patients, 35 with unknown treatment history). MDR-TB was detected in 4.5% (95%CI 3.7-5.4) of new patients, and 7.9% (95%CI 6.0-10.1) of individuals treated previously. MDR-TB was significantly associated with previous treatment (OR 1.8, 95%CI 1.3-2.5) but not with HIV infection, sex, age or other demographic factors. Prior treatment failure demonstrated the strongest association with MDR-TB (OR 17.6, 95%CI 5.3-58.7).CONCLUSION: The prevalence of MDR-TB among new TB patients in Namibia is high and, compared with the first drug resistance survey, has decreased significantly among those treated previously. Namibia should implement routine screening of drug resistance among all TB patients.

Pattern of Anti-Tuberculosis Drug Resistance in HIV-Associated Tuberculous Meningitis Patients

Multidrug-resistant tuberculosis (MDR-TB) is a major public health problem worldwide. Human immunodeficiency virus (HIV) infection-associated tuberculous meningitis (TBM) further complicates the patient management and causes poor prognosis. A cross-sectional study was carried out to determine anti-TB drug susceptibility pattern of Mycobacterium tuberculosis (MTB) isolates from HIV-associated TBM patients at Waibagi, Thakayta and Mingaladon Specialist Hospitals in Yangon, Myanmar. From January to October 2017, cerebrospinal fluid (CSF) specimens collected from 140 HIV infected patients with clinically presumptive TBM were applied for isolation and drug susceptibility testing. First-line drug susceptibility testing were carried out by solid culture-based proportion method. Drug susceptibility patterns of pyrazinamide, fluoroquinolones and second-line injectable drugs were determined by liquid culture-based Mycobacterial Growth Indicator Tube method. There were 17 culture positives and confirmed as MTB out of 140 specimens. Among them,10 isolates (58.8%) were resistant to at least one of the first-line anti-TB drugs. Eight isolates (47.1%) showed multidrug resistance but there was no extensively drug resistance. HIV-associated TBM patients with previous anti-TB treatment history and CD4 cell count of less than 100 cells/μl were significantly more prone to develop drug resistance. These findings highlight burdens of anti-TB drug resistance among HIVassociated TBM patients and support the need of elaborative management strategies.

757. Community Prevalence of Bacteriologically Confirmed Pulmonary Tuberculosis: A 7-Year Retrospective Study

BackgroundIt is estimated that about 40% of the Indian population is infected with Mycobacterium tuberculosis (TB), the vast majority of whom have latent TB. However, asymptomatic pulmonary carriage of the TB bacteria contributes to sustenance of the disease in the community and subsequent transmission. The present study was carried out to see the prevalence of culture positive pulmonary tuberculosis in apparently asymptomatic individuals from the community.MethodsThe study population consisted of individuals wishing to migrate to the USA/UK/Canada/Australia and submitting for the mandatory health check prior to obtaining the Visa. Chest X-ray was the initial screening test for diagnosis of tuberculosis. Individuals with any X-ray abnormalities were directed to submit three sputum samples for microscopy and culture which was done on automated culture systems (BacTALERT and MGIT). First-line drug susceptibility (INH, Rifampicin, Pyrazinamide, Ethambutol, Streptomycin) testing data were retrieved wherever available. Data were obtained for a period of 7 years from August 2010 to July 2017.ResultsA total of 140,499 individuals presented for the health check. Of these, 1,002 (0.7%) were further investigated using sputum microscopy and culture based on chest X-ray findings. Of these, 42 (0.4%) individuals were sputum culture positive for Mycobacterium tuberculosis. Except two, none had any respiratory complaints. Eleven (27.5%) of them were smear positive for acid fast bacilli. Most of the patients (30%) belonged to the age group of 18–25 years. Eighty-four percent had no prior history of tuberculosis or treatment for TB. Fifty-nine percent isolates were sensitive to all first-line drugs (Isoniazid, rifampicin, pyrazinamide, ethambutol and streptomycin). Twenty-seven percent were resistant to pyrazinamide alone. Fourteen percent were resistant to more than one first-line drug. There were no cases of multidrug resistance.ConclusionThis is a unique large-scale study which assesses prevalence of culture positive pulmonary tuberculosis in the urban Indian community. It stresses the need for more stringent public health measures to curb transmission of the disease in such a high endemic region such as India.Disclosures All authors: No reported disclosures.

Dramatic shortening of the diagnosis of multidrug-resistant tuberculosis by the detection of rifampicin resistance using a genotypic method: GeneXpert MTB/RIF assay

In spite of all the evolutions in medicine, tuberculosis (TB) continues to be a terrifying contagious disease. In addition, the rise of multidrug-resistant TB (MDR-TB) is considered as a thorny problem that has greatly hindered the efforts of TB control. The classical drug susceptibility testing (DST) is the reference technique, but it takes many weeks for the identification of TB and MDR-TB. On the other hand, GeneXpert Mycobacterium tuberculosis (MTB)/rifampicin (RIF) has dramatically shortened the identification of both MTB and RIF resistance from weeks to only 2 h leading to a great breakthrough in the modern medicine. The aim of this study is to assess the use of GeneXpert assay for accelerating the diagnosis of MDR-TB in comparison to phenotypic DST by MGIT960 as the reference method. A total of 81 confirmed TB cases by both MGIT960 culture and GeneXpert were included in the current study. All sputum samples were processed for the detection of MDR-TB by both GeneXpert MTB/RIF assay and classical first-line DST method on MGIT960. Among studied TB cases, one rifampicin (RIF) monoresistance (1.2%), two isoniazid (INH) monoresistance (2.4%), and four (4.9%) MDR-TB (resistance to both RIF and INH) were identified by phenotypic methods. A significant statistical difference was found between RIF monoresistance and MDR-TB (P value 0.05). The sensitivity, specificity, negative, and positive predictive value of GeneXpert assay for identification of rifampicin resistance compared to DST as a reference method were 100, 98.7, 100, and 83.3%, respectively. It was concluded that the results of GeneXpert MTB/RIF and the standard phenotypic DST on MGIT960 for detection of RIF resistance were nearly the same regarding the sensitivity and specificity. Moreover, GeneXpert MTB/RIF was superior to DST on MGIT960 owing to its ability to dramatically shorten the period of MDR-TB diagnosis from weeks to only 2 h with fewer biohazard risks. Resistance to RIF could be used as a good foreteller for MDR-TB as most of RIF resistance are accompanied with isoniazid resistance.

Extensively drug-resistant tuberculosis (XDR-TB) in Morocco.

Extensively drug-resistant tuberculosis (XDR-TB) has recently been identified as a major global health threat. The aim of this study was to evaluate the presence of XDR-TB among Mycobacterium tuberculosis isolates in Morocco and its association with demographic, clinical and epidemiological features. A total of 524 patients from the Moroccan National Tuberculosis Reference Laboratory, representative of all of the geographic regions, were subject to first-line drug susceptibility testing (DST). Subsequently, 155 isolates found to be multidrug-resistant tuberculosis (MDR-TB) underwent second-line DST. Moreover, to enhance our understanding of the genetic basis of these drug-resistant strains, drug resistance-associated mutations were investigated in isolates either identified as pre-XDR- and XDR-TB or suspected resistant using the GenoType® MTBDRsl V1.0 assay. In this study, 4 (2.6%) XDR-TB and 18 (11.6%) pre-XDR-TB isolates were identified. Agreement between the MTBDRsl assay results and phenotypic DST was 95.2% for ofloxacin, 81.0% for kanamycin and 95.2% for amikacin. To the best of our knowledge, this is the first study to evaluate the frequency of XDR-TB in Morocco. These results highlight the need to reinforce the TB management policy in Morocco with regard to control and detection strategies in order to prevent further spread of XDR-TB isolates.

Tuberculosis drug resistance in Southern Mozambique: results of a population-level survey in the district of Manhiça.

Mozambique, one of the world's high tuberculosis (TB) burden countries, has conducted only one national-level drug resistance survey, in 2007-2008. To determine the drug resistance patterns of laboratory-confirmed TB cases. This was a population-level survey conducted over a 1-year period in the district of Manhiça. All laboratory-confirmed cases were evaluated for first-line anti-tuberculosis drug susceptibility testing using liquid culture. Resistance to at least one first-line drug was observed in 44 of 276 isolates (15.9%). Prevalence of drug resistance to each of the five anti-tuberculosis drugs tested was 4.0% for streptomycin, 10.1% for isoniazid (INH), 6.2% for rifampicin, 3.6% for ethambutol and 1.1% for pyrazinamide. The overall prevalence of multidrug-resistant TB (MDR-TB) was 5.1%: 3.8% (95%CI 2.0-7.0) in new and 13.2% (95%CI 5.8-27.3) in retreatment cases. Respectively 4.6% and 2.6% of new and retreatment cases were INH-monoresistant. Previous history of anti-tuberculosis treatment was associated with having MDR-TB (OR 4.3, 95%CI 1.3-14.1). The prevalence of drug resistance in the district of Manhiça is slightly higher than, but still compatible with, previous national estimates. INH monoresistance was high, posing the risk of hidden monotherapy in the continuation phase.

Implementation of quality management systems and progress towards accreditation of National Tuberculosis Reference Laboratories in Africa.

BackgroundLaboratory services are essential at all stages of the tuberculosis care cascade, from diagnosis and drug resistance testing to monitoring response to treatment. Enabling access to quality services is a challenge in low-resource settings. Implementation of a strong quality management system (QMS) and laboratory accreditation are key to improving patient care.ObjectivesThe study objective was to determine the status of QMS implementation and progress towards accreditation of National Tuberculosis Reference Laboratories (NTRLs) in the African Region.MethodAn online questionnaire was administered to NTRL managers in 47 World Health Organization Regional Office for Africa member states in the region, between February and April 2015, regarding the knowledge of QMS tools and progress toward implementation to inform strategies for tuberculosis diagnostic services strengthening in the region.ResultsA total of 21 laboratories (43.0%) had received SLMTA/TB-SLMTA training, of which 10 had also used the Global Laboratory Initiative accreditation tool. However, only 36.7% of NTRLs had received a laboratory audit, a first step in quality improvement. Most NTRLs participated in acid-fast bacilli microscopy external quality assurance (95.8%), although external quality assurance for other techniques was lower (60.4% for first-line drug susceptibility testing, 25.0% for second-line drug susceptibility testing, and 22.9% for molecular testing). Barriers to accreditation included lack of training and accreditation programmes. Only 28.6% of NTRLs had developed strategic plans and budgets which included accreditation.ConclusionGood foundations are in place on the continent from which to scale up accreditation efforts. Laboratory audits should be conducted as a first step in developing quality improvement action plans. Political commitment and strong leadership are needed to drive accreditation efforts; advocacy will require clear evidence of patient impact and cost-benefit.

Molecular analysis of pyrazinamide resistance in Mycobacterium tuberculosis in Vietnam highlights the high rate of pyrazinamide resistance-associated mutations in clinical isolates

Pyrazinamide (PZA) is a key antibiotic in current anti-tuberculosis regimens. Although the WHO has stressed the urgent need to obtain data on PZA resistance, in high tuberculosis burden countries, little is known about the level of PZA resistance, the genetic basis of such resistance or its link with Mycobacterium tuberculosis families. In this context, this study assessed PZA resistance through the molecular analysis of 260 Vietnamese M. tuberculosis isolates. First-line drug susceptibility testing, pncA gene sequencing, spoligotyping and mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR) typing were performed. Overall, the pncA mutation frequency was 38.1% (99 out of 260 isolates) but was higher than 72% (89 out of 123 isolates) in multidrug and quadruple-drug resistant isolates. Many different pncA mutations (71 types) were detected, of which 55 have been previously described and 50 were linked to PZA resistance. Among the 16 novel mutations, 14 are likely to be linked to PZA resistance because of their mutation types or codon positions. Genotype analysis revealed that PZA resistance can emerge in any M. tuberculosis cluster or family, although the mutation frequency was the highest in Beijing family isolates (47.7%, 62 out of 130 isolates). These data highlight the high rate of PZA resistance-associated mutations in M. tuberculosis clinical isolates in Vietnam and bring into question the use of PZA for current and future treatment regimens of multidrug-resistant tuberculosis without PZA resistance testing.Emerging Microbes & Infections (2017) 6, e86; doi:10.1038/emi.2017.73; published online 11 October 2017

Genotypic characterization of rpoB, katG and inhA gene of multi drug tuberculosis isolates from extra pulmonary tuberculosis

Background: Multidrug-resistant tuberculosis (MDR-TB) has appeared public health concern worldwide. Circulating of drug resistance strains is rising problem in MDR-TB among extra pulmonary TB (EPTB) cases. The objective of this study was to the genotypic characterization of MDR-TB isolates from EPTB and correlate with a phenotypic MDR-TB pattern in this region. Methods: This was study conducted prospectively manner. One hundred and sixty-four M. tuberculosis complex isolates were processed for first-line phenotypic drug susceptibility testing to rifampicin, isoniazid (INH), streptomycin, and ethambutol. Phenotypic confirmed MDR-TB strains were further characterized by gene sequencing for genotypic analysis of rpoB, katG, and inhA. Results: Among 164 MTBC strains, 39.1% of strains were resistant to first-line antitubercular drugs, and 13.4% were MDR-TB along with EPTB cases. In one strain, katG and inhA gene were absent in sequencing analysis. S531 L (61.9%) and S315T (71.4%) mutations were the most predominant mutation in MDR-TB isolates among EPTB cases. Conclusion: Molecular drug resistance testing allows to improved diagnosis, reduces the risk of additional resistance and effective treatment of drug resistance TB. Molecular DST testing can help in the detection for MDR-TB which helps in the prompt initiation of effective antitubercular therapy.

A study on pre-XDR &amp; XDR tuberculosis &amp; their prevalent genotypes in clinical isolates of Mycobacterium tuberculosis in north India

Background & objectives:Pre-extensively drug resistant (pre-XDR) and extensively drug resistant tuberculosis (XDR-TB) have been areas of growing concern, and are posing threat to global efforts of TB control. The present study was planned to study the presence of pre-XDR and XDR Mycobacterium tuberculosis and their genotypes in clinical isolates obtained from previously treated cases of pulmonary TB.Methods:A total of 219 isolates obtained from previously treated cases of pulmonary TB were subjected to first-line (streptomycin, isoniazid, rifampicin and ethambutol) and second-line (ofloxacin, kanamycin, capreomycin and amikacin) drug susceptibility testing on solid Lowenstein-Jensen medium by proportion method. Genotyping was done for pre-XDR and XDR-TB isolates using 12 loci Mycobacterial Interspersed Repetitive Units-Variable Number Tandem Repeats (MIRU-VNTR).Results:Multi-drug resistance was observed in 39.7 per cent (87/219) isolates. Pre-XDR and XDR M. tuberculosis isolates amongst 87 multi-drug resistant (MDR) TB isolates were 43 (49.4%) and 10 (11.4%), respectively. Two most dominant genotypes among pre-XDR and XDR M. tuberculosis isolates were Beijing and Delhi/CAS types.Interpretation & conclusions:Resistance to second-line anti-tubercular drugs should be routinely assessed in areas endemic for TB. Similar genotype patterns were seen in pre-XDR and XDR-TB isolates. Beijing and Delhi/CAS were predominant genotypes.

Evaluation of use of line probe assay on smear-positive direct specimen from extra-pulmonary tuberculosis site

BackgroundLine probe assay (LPA) is used for first-line drug susceptibility testing (DST) of smear-positive pulmonary tuberculosis (TB) patients. For extra-pulmonary (EP) and smear-negative TB patients, the samples are inoculated in culture and isolates of Mycobacterium tuberculosis (MTB) are tested on LPA. This results in considerable delay and loses the benefit of rapid diagnostics. In the present study, smear-positive EP specimens were tested directly on LPA and their results were compared with LPA conducted on culture isolates of same specimens. MethodAll EP specimens received from different parts of Gujarat State in 2014 were subjected to ZN smear microscopy and inoculated on liquid culture. Smear-positive samples were directly tested with LPA. Simultaneously, culture isolates of MTB were also subjected to LPA. Results of LPA conducted on both direct specimen and culture isolates were compared. ResultOf 391 extra-pulmonary specimens, 177 were smear positive and tested directly on LPA. Simultaneously, 88 were culture positive and their isolates were tested on LPA. With LPA on direct specimen, 127 (32%) had valid results with median time to diagnose rifampicin resistance of 5 days (IQR 2-7). In comparison, 88 (23%) specimens had valid results with culture isolates tested on LPA and with longer turnaround time (18–40 days). Among 51 samples, with valid LPA results both on direct samples and isolates, 50 (98%) had concordance for drug resistance pattern. ConclusionThere is advantage in testing extra-pulmonary smear-positive samples directly on LPA and the results would also be available rapidly.

Tuberculosis in Qatar

Tuberculosis (TB) remains a common health problem in the State of Qatar. Qatar has a population of around 2.2 million; about 25% are Qatari Nationals. Most of the population reside in the capital Doha. The incidence rate of TB was 41/100,000 in 2012. 90% of the patients are non-Qataris. Most of the TB patients are among male laborers from Asian high TB endemic areas. The size of the labor force in Qatar increased by fourfold during the last decade.Qatar has one National TB Reference Laboratory, which covers all country sectors, public (primary health centers and all public hospitals) and private hospitals and clinics. Qatar has a highly effective National TB Control Program.The Qatar National TB Reference Laboratory does a full range of laboratory diagnosis, microscopy, culture (GMIT 960 and LJ media), identification by immuno-chromogenic (BD MGIT TBc identification test) and molecular methods (Xpert MTB/RIF and Hain System). First-line drug susceptibility testing is done for all MTBC positive patients and repeated after 6months if the results are still culture positive. Second-line drug susceptibility test for MDR is done at the Mayo Clinic Reference Laboratory. The lab receives an average of 70 samples daily, the majority for culture. Xpert MTB/RIF is performed on all extra-pulmonary samples directly and is also performed on at least one sample for all TB patients to speed up the identification and Rifampicin susceptibility testing. Smear positivity rate ranges from 50% to 80%. In the near future, molecular typing will be performed on all MTBC isolates from the patients.Hamad Medical Corporation is CAP accredited, and the lab is also CAP accredited. External quality assurance covers microscopy, culture and drug susceptibility testing. All TB care, including care for MDR-TB and latent TB infection, are available free of charge for Qatari and non-Qatari residents.

Drug-resistant tuberculosis in Eastern Europe: challenges and ways forward.

Encouragingly, global rates of new tuberculosis (TB) cases have been falling since 2005, in line with the Millennium Development Goal targets; however, cases of multidrug-resistant (MDR-) and extensively drug-resistant TB (XDR-TB) have been increasing. Fifteen of the world's 27 high MDR- and XDR-TB burden countries are in the World Health Organization (WHO) European Region, of which 10 are in Eastern Europe (including Baltic and Caucasus countries). To address the MDR- and XDR-TB situation in the WHO European Region, a Consolidated Action Plan to Prevent and Combat M/XDR-TB (2011-2015) was developed for all 53 Member States and implemented in 2011. Since the implementation of the Action Plan, the proportion of MDR-TB appears largely to have levelled off among bacteriologically confirmed TB cases in high-burden countries with universal or near universal (>95%) first-line drug susceptibility testing (DST). The treatment success rate, however, continues to decrease. A contributing factor is the substantial proportion of MDR-TB cases that are additionally resistant to either a fluoroquinolone, a second-line injectable agent or both (XDR-TB); high-burden country proportions range from 12.6% to 80.4%. Proportions of XDR-TB range from 5% to 24.8%. Despite much progress in Eastern Europe, critical challenges remain as regards access to appropriate treatment regimens; patient hospitalisation; scale-up of laboratory capacity, including the use of rapid diagnostics and second-line DST; vulnerable populations; human resources; and financing. Solutions to these challenges are aligned with the Post-2015 Global TB strategy. As a first step, the global strategy should be adapted at regional and country levels to serve as a framework for immediate actions as well as longer-term ways forward.