Second-line Drug Susceptibility Testing Research Articles

Trends in and Risk Factors for Drug Resistance in Mycobacterium tuberculosis in HIV-Infected Patients.

Trends in and risk factors for drug resistance in Mycobacterium tuberculosis (M. tuberculosis) in human immunodeficiency virus (HIV)-infected patients with active tuberculosis were analyzed. The clinical data of M. tuberculosis and HIV-coinfected patients treated at the Shanghai Public Health Clinical Center between 2010 and 2022 were collected. The diagnosis of tuberculosis was confirmed by solid or liquid culture. The phenotypic drug susceptibility test was carried out via the proportional method, and the resistance to first-line and second-line drugs was analyzed. Logistic regression analysis was performed to identify associated risk factors for drug resistance in M. tuberculosis. Of the 304 patients with a M. tuberculosis-positive culture and first-line drug susceptibility test results, 114 (37.5%) were resistant to at least one first-line anti-tuberculosis drug. Of the 93 patients with first-line and second-line drug susceptibility test results, 40 (43%) were resistant to at least one anti-tuberculosis drug, and 20 (21.5%), 27 (29.0%), 19 (20.4%), 16 (17.2%), and 14 (15.1%) were resistant to rifampicin, streptomycin, ofloxacin, levofloxacin, and moxifloxacin, respectively; 17 patients (18.3%) had multidrug-resistant tuberculosis (MDR-TB). Between 2010 and 2021, the rate of resistance to streptomycin and rifampicin ranged from 14.3% to 40.0% and from 8.0% to 26.3%, respectively, showing an increasing trend year by year. From 2016 to 2021, the rate of resistance to quinolones fluctuated between 7.7% and 27.8%, exhibiting an overall upward trend. Logistic regression analysis showed that being aged <60 years old was a risk factor for streptomycin resistance, mono-drug resistance, and any-drug resistance (RR 4.139, p = 0.023; RR 7.734, p = 0.047; RR 3.733, p = 0.009). Retreatment tuberculosis was a risk factor for resistance to rifampicin, ofloxacin, of levofloxacin (RR 2.984, p = 0.047; RR 4.517, p = 0.038; RR 6.277, p = 0.014). The drug resistance rates of M. tuberculosis to rifampicin and to quinolones in HIV/AIDS patients were high and have been increasing year by year. Age and a history of previous anti-tuberculosis treatment were the main factors associated with the development of drug resistance in HIV/AIDS patients with tuberculosis.

Phenotypic and Genotypic Drug Resistance of Mycobacterium tuberculosis Strains Isolated from HIV-Infected Patients from a Third-Level Public Hospital in Mexico.

Drug-resistant tuberculosis (TB) is associated with higher mortality rates in patients with human immunodeficiency virus (HIV). In Mexico, the number of deaths due to TB among the HIV-positive population has tripled in recent years. Ninety-three Mycobacterium tuberculosis strains isolated from the same number of HIV-infected patients treated in a public hospital in Mexico City were studied to determine the drug resistance to first- and second-line anti-TB drugs and to identify the mutations associated with the resistance. Of the 93 patients, 82.7% were new TB cases, 86% were male, and 73% had extrapulmonary TB. Most patients (94%) with a CD4 T-lymphocyte count <350 cells/mm3 were associated with extrapulmonary TB (p <0.0001), whilst most patients (78%) with a CD4 T-lymphocyte count >350 cells/mm3 were associated with pulmonary TB (p = 0.0011). Eighty-two strains were pan-susceptible, four mono-resistant, four poly-resistant, two multidrug-resistant, and one was extensively drug-resistant. In the rifampicin-resistant strains, rpoB S531L was the mutation most frequently identified, whereas the inhA C15T and katG S315T1 mutations were present in isoniazid-resistant strains. The extensively drug-resistant strain also contained the mutation gyrA D94A. These data highlight the need to promptly diagnose the drug resistance of M. tuberculosis among all HIV-infected patients by systematically offering access to first- and second-line drug susceptibility testing and to tailor the treatment regimen based on the resistance patterns to reduce the number of deaths in HIV-infected patients.

Time to Treatment and Risk Factors for Unsuccessful Treatment Outcomes among People Who Started Second-Line Treatment for Rifampicin-Resistant or Multi-Drug-Resistant Tuberculosis in the Kyrgyz Republic, 2021.

The Kyrgyz Republic is a high-burden country for rifampicin resistant/multi-drug resistant tuberculosis (RR/MDR-TB). TB control efforts rely on early diagnosis and initiation of people on effective regimens. We studied the interval from diagnosis of RR-TB to starting treatment and risk factors for unsuccessful outcomes among people who started RR/MDR-TB treatment in 2021. We conducted a cohort study using country-wide programme data and used binomial regression to determine associations between unsuccessful outcomes and predictor variables. Of the 535 people included in the study, three-quarters were in the age category 18-59 years, and 68% had past history of TB. The median (IQR) time from onset of TB symptoms to diagnosis was 30 (11-62) days, 1 (0-4) days from diagnosis to starting treatment, and 35 (24-65) days from starting treatment to receipt of second-line drug susceptibility test (SL-DST) results. Overall, 136 (25%) had unsuccessful outcomes. Risk factors for unsuccessful outcomes were being homeless, fluroquinolone resistance, having unknown HIV status, past TB treatment, male gender and being unemployed. Treatment outcomes and the interval from diagnosis to starting treatment were commendable. Further reductions in unsuccessful outcomes by be achieved through ensuring timely diagnosis and access to SL-DSTs and by reducing the proportion of people who are lost to follow-up.

Prevalence of pre-extensively drug-resistant tuberculosis (Pre XDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) among extra pulmonary (EP) multidrug resistant tuberculosis (MDR-TB) at a tertiary care center in Mumbai in pre Bedaquiline (BDQ) era.

Drug-resistant tuberculosis (DR-TB) is the most exigent and calamitous challenge encountered in treatment of TB. Extra pulmonary (EP) DR-TB poses a complex diagnostic and therapeutic challenge owing to myriad of presentations and paucibacillary nature. Data available on this subset is limited. We studied the prevalence of EPDR-TB cases among the total DR-TB cases visiting our Programmatic management of Drug-Resistant TB (PMDT) site. We also studied the demographic and microbiological profile of these cases and analyzed the prevalence of pre-extensively drug-resistant TB (pre XDR-TB) and extensively drug-resistant TB (XDR-TB) among patients of EPDR-TB in pre Bdq era. Of the 1086 DR-TB patients, 64 (5.89%) were cases of EPDR-TB. Seven out of 64 (10.93%) were primary EPDR-TB. The site wise distribution of cases was 34 (53.125%) lymph node DR-TB, 18 (28.125%) pleural DR-TB, 9 (14.0625%) spinal DR-TB/paraspinal abscess/psoas abscess, 1 case (1.5625%) each of abdominal DR-TB, sternal and gluteal abscess. On the basis of the second-line drug susceptibility testing (DST), patients were grouped into: (1) multidrug-resistant TB (MDR-TB), (2) MDR-TB with fluoroquinolone (FQ) resistance {pre XDR XDR-TB (FQ)}, (3) MDR-TB with second-line injectable (SLI) resistance {pre XDR XDR-TB (SLI)}, (4) XDR-TB. Of the 64 patients, 43 (67.185%) had MDR-TB, 19 (29.687%) had preXDR-TB (FQ), none had preXDR-TB (SLI) and 2 (3.125%) had XDR-TB. Gastro esophageal reflux disease (GERD) was the most common comorbidity seen in 26 (40.6%) patients, followed by anemia in 5 (7.8%), psychiatry problems 5 (7.8%), hypertension in 3 (4.6%), renal disorders in 2 (3.1%) while thyroid disorder, HIV and thalassemia in 1 each (1.5%). EPDR-TB forms a small but significant proportion of total DR-TB. Lymph node DR-TB is its most common subclass. Our study emphasises the momentousness and essentiality of baseline DST to FQ and SLI in patients of DR-TB. This enables an appropriate modification of therapy at baseline itself to better the treatment outcomes. We observed a strikingly high proportion of preXDR-TB (FQ) in our study group.

Experience on the first national anti-TB drug resistance survey (DRS) in Timor-Leste

BackgroundA national drug resistance survey (DRS) was implemented for the first time in Timor-Leste (TL) in 2019. The primary objective of the survey was to assess the prevalence of drug resistance among new and previously treated pulmonary TB patients in the country.MethodsThis nation-wide cross-sectional survey was conducted in 2019 targeting all new and previously treated sputum smear-positive pulmonary TB patients. Sputum samples were submitted to the National TB Reference Laboratory for confirmation of TB and to determine resistance to rifampicin by Xpert MTB/RIF. Culture was performed on solid media, and culture isolates of confirmed TB cases were shipped to the WHO Supranational TB Reference Laboratory in Chennai, India for whole genome sequencing (WGS). Survey summary statistics, data cross-tabulations and analysis of potential risk factors of rifampicin-resistant TB (RR-TB) were conducted using R statistical software (version 3.5.2).ResultsA total of 953 sputum-smear positive patients were enrolled, of which 917 were confirmed as positive for TB by either Xpert MTB/RIF or culture. An electronic web-based system was used for entry and storage of the data. Rifampicin resistance was detected among 0.6% (95% CI 0.2–1.3) of new cases and 2.7% (95% CI 0.5- 8.2) of previously treated cases. WGS was conducted for validation purposes on 65 randomly selected isolates (29% of RR-TB (2/7) and 7% of RS-TB (63/910) by Xpert MTB/RIF or pDST). The original test results agreed with the WGS validation results for 62/64 isolates (97%).ConclusionThe prevalence of RR-TB in Timor-Leste is relatively low compared to the estimated proportions of RR-TB in the WHO South-East Asia Region (2.5% [95% CI 1.9–3.3] among new cases and 14% [95% CI 7.7–21] among previously treated cases). The rapid sputum collection and transportation mechanism implemented in the survey demonstrates its feasibility in low resource settings and should be replicated for routinely transporting TB specimens from microscopy labs to GeneXpert sites. Establishment of in-country capacity for rapid molecular diagnostics for both first- and second-line DST is an immediate need for achieving universal drug susceptibility testing (DST) to guide appropriate patient management.

Second-Line Drug Susceptibility Testing of Mycobacterium tuberculosis Isolates from Patients in Bayelsa State, Nigeria

Aim: To determine the second-line drug susceptibility testing of Mycobacterium tuberculosis isolates from patients in Bayelsa State, Nigeria.&#x0D; Study Design: A cross sectional study was carried out in this research.&#x0D; Place and Duration of Study: Directly Observed Treatment Short-course (DOTS) Centers across Bayelsa State, between March 2020 and November 2021.&#x0D; Methodology: Ethical approval was obtained from Bayelsa State Ministry of Health, Yenagoa, Nigeria. Informations such as age, sex and residential address was obtained with the help of a questionnaire. A total of 100 sputum sample was collected from 100 patients across all the Local Government Areas. Sputum sample decontamination and homogenization was done using the Sodium Hydroxide/N- Acetyl -L- Cysteine Citrate Solution. Sputum samples were cultured on solid Lowenstein Jensen (LJ) Media. All growths on LJ media were confirmed with Ziehl Neelsen staining and Standard Bioline antigen test. Drug susceptibility test was carried out after bacterial DNA was extracted and amplified using Line Probe Assay (MTBDRplus assay ver 2).&#x0D; Results: Out of 100 patients, 15 had confirmed growth of Mycobacterium tuberculosis. All isolate had no form of mutation on gyr gene, meaning 100% of isolates were susceptibility to flouroquinolones. There were also no mutation detected on rrs gene therefore all strains are also susceptible to Kanamycin, Amikasin and capreomycin. Out of the 15 isolates 14 had no mutation on the eis gene while 1% had mutation of WT2 and MUT1.&#x0D; Conclusion: A good percentage of the isolates are susceptible to second line drugs, therefore cases of extensive drug resistance is not common in Bayelsa State, Nigeria.

Multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis strains in geriatrics: An analysis and its implications in tuberculosis control

ObjectiveThis study aimed to analyze the trends of tuberculosis (TB) disease, drugs susceptibility patterns in geriatric TB over a period of three years (from 2010 to 2012). Materials & methodsIn this study, laboratory data on diagnosis of geriatric tuberculosis suspected patients (age ≥60 years) was analyzed retrospectively at National Reference Laboratory (NRL). ResultsAmong 12,140 geriatric TB suspects, 1621 (13%) were acid-fast bacillus (AFB) smear-positive and 10,519 (87%) were smear-negative. Analysis of 915 culture results showed 470 (51%) as positive for Mycobacterium tuberculosis complex (MTBC), 63 (7%) contaminated and 36 (4%) identified as mycobacteria other than tuberculosis (MOTT). A total 210/470 (45%) were multidrug-resistant TB (MDR-TB) strains. Among the mono-resistant strains, isoniazid mono-resistant was found more frequently (134/470, 28%) whereas, it was least among rifampicin mono-resistant 5/470 (1%). The second-line drug susceptibility testing (DST) results showed 7% (17/240) extensively drug-resistant TB (XDR-TB) strains. Most common second line mono-resistant strain was observed with ofloxacin, 16% (38/240). ConclusionThis study shows high number of MDR/XDR geriatric TB patients at tertiary care TB hospital. The study highlighted the need of separate line of early identification, diagnosis and treatment of geriatric TB patients. However, further study with improved sample size may needed to confirm the findings.

Accuracy and Effect of Rapid Line Probe Assay Testing for First- and Second-Line Tuberculosis in a High-Volume Programmatic Laboratory

Background: Rapid drug susceptibility testing (DST) is crucial to confirm eligibility for new tuberculosis (TB) regimens. Genotype MTBDRsl is a World Health Organization (WHO)-endorsed assay yet performance data on smear-negative sputum are scarce and programmatic adoption limited. Methods: Sputa from Xpert MTB/RIF-rifampicin resistant patients (n=951) were programmatically tested by Genotype MTBDRplus and Genotype MTBDRsl (both v2). Phenotypic DST was the reference standard for MTBDRsl. Discrepant results underwent Sanger sequencing. Findings: 89% (849/951) of sputa were culture-positive [56% (476/849) smear-negative]. MTBDRplus had non-actionable results (control and/or TB-detection bands absent or invalid; precluding resistance reporting) in 3% (11/373) and 19% (92/476; p=0.001) of smear-positives and -negatives, respectively. Of Xpert rifampicin-resistant specimens, 23% (172/746) were MTBDRplus isoniazid-susceptible. 85% (22/26) Xpert rifampicin-resistant, MTBDRplus rifampicin-susceptible specimens resolved in favour of Xpert by sequencing. MTBDRsl had at least one non-actionable result for 10% (35/342) and 40% (171/427; p=0.001) of smear-positives and -negatives, respectively. MTBDRsl sensitivity in smear-negatives was 84% (95% CI 67-93) for fluoroquinolones, 81% (54-95) for second-line injectables, and 57% (28-82) for resistance to both. Specificities were 93% (89-98), 88% (81-93), and 97% (91-99), respectively. Days to second-line susceptibility reporting with the advent of rapid direct testing improved vs. prior standard-of-care [6 (5-7) vs. 37 (35-46); p<0.001]. Interpretation: MTBDRplus is unsuitable for Xpert-detected rifampicin-resistance confirmation and isoniazid are likely still useful in many Xpert rifampicin-resistant patients. MTBDRsl is accurate for ruling-in second-line resistance, however, non-actionable result rates are unacceptably high (4/10 smear-negatives failed, which is not reflected in sensitivity estimates). Better second-line DSTs are needed. Funding Information: The work was funded by Stellenbosch University Faculty of Health Sciences, the National Research Foundation and Harry Crossley. RMW acknowledges funding from the South African Medical Research Council. GT acknowledges funding from the EDCTP2 programme supported by the European Union (grant SF1401, OPTIMAL DIAGNOSIS) and the National Institute of Allergy and Infection Diseases of the National Institutes of Health (U01AI152087). Declaration of Interests: All authors reported no conflict of interest. Ethics Approval Statement: This study was done in accordance with relevant guidelines and regulations, approved by the Health Research Ethics Committee of Stellenbosch University (N16/04/045) and the Western Cape Province Department of Health (2016RP18 637). Permission was granted to access anonymised residual specimens collected as part of routine diagnostic practice and informed consent waived.

Extract from used Xpert MTB/RIF Ultra cartridges is useful for accurate second-line drug-resistant tuberculosis diagnosis with minimal rpoB-amplicon cross-contamination risk

Xpert MTB/RIF Ultra (Ultra) detects Mycobacterium tuberculosis and rifampicin resistance. Follow-on drug susceptibility testing (DST) requires additional sputum. Extract from the diamond-shaped chamber of the cartridge (dCE) of Ultra’s predecessor, Xpert MTB/RIF (Xpert), is useful for MTBDRsl-based DST but this is unexplored with Ultra. Furthermore, whether CE from non-diamond compartments is useful, the performance of FluoroType MTBDR (FT) on CE, and rpoB cross-contamination risk associated with the extraction procedure are unknown. We tested MTBDRsl, MTBDRplus, and FT on CEs from chambers from cartridges (Ultra, Xpert) tested on bacilli dilution series. MTBDRsl on Ultra dCE on TB-positive sputa (n = 40) was also evaluated and, separately, rpoB amplicon cross-contamination risk . MTBDRsl on Ultra dCE from dilutions ≥103 CFU/ml (CTmin <25, >“low semi-quantitation”) detected fluoroquinolone (FQ) and second-line injectable (SLID) susceptibility and resistance correctly (some SLIDs-indeterminate). At the same threshold (at which ~85% of Ultra-positives in our setting would be eligible), 35/35 (100%) FQ and 34/35 (97%) SLID results from Ultra dCE were concordant with sputa results. Tests on other chambers were unfeasible. No tubes open during 20 batched extractions had FT-detected rpoB cross-contamination. False-positive Ultra rpoB results was observed when dCE dilutions ≤10−3 were re-tested. MTBDRsl on Ultra dCE is concordant with isolate results. rpoB amplicon cross-contamination is unlikely. These data mitigate additional specimen collection for second-line DST and cross-contamination concerns.

Prevalence of Pre - Extensively Drug Resistance Tuberculosis (Pre XDR-TB) &amp; Extensively Drug Resistance Tuberculosis (XDR-TB) among Pulmonary Multidrug Resistance Tuberculosis at a Tertiary Care Hospital, Jamnagar

Aims and Objective: Many diseases have a high prevalence in India, accounting for one-fourth of the Tuberculosis (TB) cases in the world. In our study, we aimed to find the prevalence of Pre XDR-TB and XDR-TB amongst newly diagnosed cases of pulmonary MDR-TB who had never been previously treated with second-line drugs. A prospective study was conducted in Culture and Drug susceptibility testing laboratory, Jamnagar and its associated Drug-Resistant Tuberculosis (DR-TB) centre.&#x0D; Materials and Methods: Baseline second-line liquid culture DST has been recently integrated with the Revised National Tuberculosis Control Programme (RNTCP) diagnostic algorithm. We included 500 patients who were diagnosed in cases of pulmonary MDR-TB never exposed to second-line TB-Drugs. Mycobacterial Growth Indicator Tube method conducted in an RNTCP accredited Culture and Drug susceptibility testing laboratory, Jamnagar, as part of the evaluation in the public healthcare system from where patients were referred for diagnosis to us.&#x0D; Results: 585 MDR suspected sputum samples were received, 466 sputum samples were showing culture positive for acid-fast bacilli which were screened against second-line drug susceptibility testing by using of BACTEC MGIT 960 (MGIT 960) instrument. About 293 Mycobacterium samples were MDR-TB, 151 were Pre- XDR TB and 22 were XDR-TB.&#x0D; Conclusion: The prevalence of Pre XDR-TB and XDR-TB among MDR-TB patients were 32.4% and 4.7% respectively. The high prevalence of Pre XDR-TB (FQ) is alarming and of concern in the management of MDR-TB control in Jamnagar area.

Detection of Second Line Drug Resistance among Drug Resistant Mycobacterium Tuberculosis Isolates in Botswana.

The emergence and transmission of multidrug resistant (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis (M.tb) strains is a threat to global tuberculosis (TB) control. The early detection of drug resistance is critical for patient management. The aim of this study was to determine the proportion of isolates with additional second-line resistance among rifampicin and isoniazid resistant and MDR-TB isolates. A total of 66 M.tb isolates received at the National Tuberculosis Reference Laboratory between March 2012 and October 2013 with resistance to isoniazid, rifampicin or both were analyzed in this study. The genotypes of the M.tb isolates were determined by spoligotyping and second-line drug susceptibility testing was done using the Hain Genotype MTBDRsl line probe assay version 2.0. The treatment outcomes were defined according to the Botswana national and World Health Organization (WHO) guidelines. Of the 57 isolates analyzed, 33 (58%) were MDR-TB, 4 (7%) were additionally resistant to flouroquinolones and 3 (5%) were resistant to both fluoroquinolones and second-line injectable drugs. The most common fluoroquinolone resistance-conferring mutation detected was gyrA A90V. All XDR-TB cases remained smear or culture positive throughout the treatment. Our study findings indicate the importance of monitoring drug resistant TB cases to ensure rapid detection of second-line drug resistance.

PO 8408 DETECTION OF EXTENSIVELY DRUG-RESISTANT TUBERCULOSIS AMONG MULTIDRUG-RESISTANTMYCOBACTERIUM TUBERCULOSISCLINICAL ISOLATES IN BOTSWANA

BackgroundThe emergence and transmission of multidrug-resistant (MDR) and extensively drug-resistant (XDR)Mycobacterium tuberculosis(Mtb) strains is a serious threat to tuberculosis control in Botswana. Early detection of drug-resistant isolates is critical to ensure optimal treatment and thereby improve treatment outcomes. The objective of this study was to determine the extent of second-line drug resistance among drug-resistant Mtb-isolates from Botswana.MethodsA total of 60 drug-resistant Mtb isolates received at Botswana National Tuberculosis Reference Laboratory between 2012 and 2013 were analysed. DNA was extracted from BD Mycobacterial Growth Indicator Tubes (MGIT) using GenoLyse DNA isolation kit (Hain Lifescience). Spoligotyping was done using a commercially available spoligotyping kit (Isogen Life Science). The spoligotype patterns were compared with existing patterns in the SITVIT2 Web database. GenoType MTBDRs assay (Hain Lifescience) was used for second-line drug susceptibility testing. Fisher’s exact test was used to test for association between drug resistance patterns and HIV status, lineage and geographical location.ResultsSeventeen distinct spoligotype patterns were detected amongst the 60 drug-resistant isolates. The most predominant lineages were Euro-American (58.3%), East Asian (25%) and Indo-Oceanic (15%). Fifty (83.3%) were MDR, 7 (11.7%) were resistant to fluoroquinolones (Pre-XDR) whereas 3 (5%) were resistant to both fluoroquinolones and second-line injectable drugs (XDR). Drug resistance profiles were significantly associated with Mtb lineage (p&lt;0.001). There was no association between drug resistance profile and HIV status (p=0.057) and geographical location (p=0.372).ConclusionThis study highlights the importance of including second-line drug susceptibility testing in a testing algorithm in Botswana. The detection of XDR isolates among MDR-TB isolates highlights the ongoing evolution of resistance and the need for strengthened treatment regimens to improve treatment outcomes and to prevent the spread of these highly resistant strains. Second-line testing will be essential if the 9 month MDR regimen is used in Botswana.

Access to second-line drug susceptibility testing results among patients with Rifampicin resistant tuberculosis after introduction of the Hain® Line Probe Assay in Southern provinces, Zimbabwe

ObjectivesTo determine the proportion of rifampicin-resistant tuberculosis (RR-TB) patients who accessed second-line drug susceptibility testing (SL-DST) results following introduction of the Hain technology in southern provinces, Zimbabwe. DesignCohort study using secondary data. ResultsXpert MTB/RIF results were used to identify 133 RR-TB patients for this study. Their mean age (SD) was 37.9 (11.1) years, 83 (62%) were males and 106 (80%) were HIV-infected. There were 6 (5%) participants who had pre-treatment attrition. Of the 133 pulmonary TB (PTB) patients, 117 (80%) had additional sputum specimens collected; 96 (72%) specimens reached the National TB Reference Laboratory (NTBRL); 95 (71%) were processed; 68 (51%) had SL-DST results. Only 53 (40%) SL-DST results reached the peripheral facilities. Median time from specimen reception at the NTBRL to SL-DSTs was 40 days, interquartile range (IQR: 28–67). Median time from presumptive diagnosis of RR-TB by health care worker to SL-DST results was 50days (IQR: 39–80), and increased to 79days (IQR: 39–101) in facilities >250km from the NTBRL. The proportion with any fluoroquinolone resistance was 9 (13.2%). ConclusionAlthough RR-TB patients with PTB were initiated timely on treatment, access to SL-DSTs by facilities needs improvement. Health inequities exist as remote areas are less likely to get SL-DST results in time.

Potentially High Number of Ineffective Drugs with the Standard Shorter Course Regimen for Multidrug-Resistant Tuberculosis Treatment in Haiti.

Multidrug-resistant tuberculosis (MDR-TB) outcomes are poor partly because of the long treatment duration; the World Health Organization conditionally recommends a shorter course regimen to potentially improve treatment outcomes. Here, we describe the drug susceptibility patterns of a cohort of MDR-TB patients in Haiti and determine the number of likely effective drugs if they were treated with the recommended shorter course regimen. We retrospectively examined drug susceptibility patterns of adults initiating MDR-TB treatment between 2008 and 2015 at the Haitian Group for the Study of Kaposi's Sarcoma and Opportunistic Infections in Port-au-Prince, Haiti. First- and second-line drug susceptibility testing (DST) was analyzed and used to determine the number of presumed effective drugs. Of the 239 patients analyzed, 226 (95%), 183 (77%), 135 (57%), and 38 (16%) isolates were resistant to high-dose isoniazid, ethambutol, pyrazinamide, and ethionamide, respectively. Eight patients (3%) had resistance to either a fluoroquinolone or a second-line injectable and none had extensively resistant TB. Of the 239 patients, 132 (55%) would have fewer than five likely effective drugs in the intensive phase of the recommended shorter course regimen and 121 (51%) would have two or fewer likely effective drugs in the continuation phase. Because of the high rates of resistance to first-line TB medications, about 50% of MDR-TB patients would be left with only two effective drugs in the continuation phase of the recommended shorter course regimen, raising concerns about the effectiveness of this regimen in Haiti and the importance of using DST to guide treatment.

Multidrug-Resistant Tuberculosis in Côte d'Ivoire from 1995 to 2016: Results of National Surveys.

SettingTuberculosis (TB) drug resistance survey was conducted in 2016–2017 to estimate the burden of drug-resistant TB in Côte d'Ivoire.DesignA cross-sectional cluster-based survey was conducted. All eligible smear positive patients were interviewed using a structured questionnaire to collect clinical and sociodemographic information and tested by the Xpert Mycobacterium tuberculosis/rifampicin (MTB/RIF) assay. If resistant to rifampicin, solid and liquid cultures were performed. Phenotypic drug susceptibility testing (DST) was conducted in liquid medium for rifampicin, isoniazid, ethambutol, streptomycin, ofloxacin, and amikacin.ResultsOf the 1105 sputum smear positive patients enrolled, 995 new and 100 previously treated patients were positive for Mycobacterium tuberculosis complex by Xpert. Proportion of patients with rifampicin resistance was 4.6% (95% CI: 2.4–6.7) and 22% (95% CI: 13.7–30.3), respectively, for new and previously treated patients. Second-line DST results were available for most rifampicin-resistant patients. None were resistant to amikacin, only two were ofloxacin-resistant. Apart from the antecedent of previously treatment for TB, no other risk factors for rifampicin resistance were detected.ConclusionPrevalence of rifampicin resistance among TB patients in Côte d'Ivoire is higher than that in other countries in the region. Surveillance of drug resistance, through an expanded GeneXpert network, and programmatic management of drug-resistant TB (PMDT) must be strengthened in Côte d'Ivoire.

Presence of Fluoroquinolone mono-resistance among drug-sensitive Mycobacterium tuberculosis isolates: An alarming trend and implications

BackgroundThe phenomenon of Drug Resistant Tuberculosis (DRTB) has been evolving aggressively and is posing great threat to tuberculosis control programs worldwide. But what really is fueling drug resistance in high disease burden countries apart from other well known risk factors, with this intent in mind the present study was developed and carried out to. The aim was to capture the presence of Fluoroquinolone (FQ) mono-resistance among drug-sensitive TB cases. MethodsA total of 1280 sputum smear-positive patients were enrolled in the study and were subjected for Drug Susceptibility Testing (DST) using First-Line Drugs (FLD's; Rifampicin, Streptomycin, Isoniazid and Ethambutol) using liquid culture DST and Line Probe Assay. These samples were further subjected to second-line drugs DST (ofloxacin and kanamycin) and DNA sequencing to confirm FQ mono-resistance. ResultsThe occurrence of FQ mono-resistance among FLD sensitive cases was found to be 3.2% (35/1099). Xpert MTB/RIF assay and rpoB gene sequencing were showed 100% concordance with FLD DST. A total of 35 FQ mono-resistant isolates were further sequenced for gyrA, gyrB and rrs genes. The gene sequencing was found to be in agreement with the DST results for 34 (3.1%) isolates with gyrA and gyrB genes. ConclusionPresence of FQ resistance among drug sensitive TB cases is a red flag sign. The findings of the present study suggest that, second-line DST should be routinely performed not only for drug-resistant cases but also for drug-sensitive cases so as to capture prevailing true drug resistance at an initial stage.

Association of gyrA and rrs gene mutations detected by MTBDRsl V1 on Mycobacterium tuberculosis strains of diverse genetic background from India

There is limited data on the use of Genotype MTBDRslVersion 1 (MTBDRsl V1) as an initial rapid screening test to rule out XDR-TB and most importantly its performance in various genotypes of Mycobacterium tuberculosis is scarcely studied. A total of 359 MDR-TB isolates were tested for gene mutations representing second line drug resistance, using the MTBDRsl_V.1 and the results were compared with phenotypic method (Bactec MGIT-960 system) for second-line drug (SLD) susceptibility testing. Genetic lineages of all these isolates were also determined using spoligotyping and SITVIT2 WEB database. The MTBDRsl V1 detected mutations in the gyrA, rrs, and emb genes in 108 (30%), 2 (0.5%) and 129 (35.9%) isolates, respectively. Remaining 120 (33.4%) had no second line drug (SLD) resistance. In 17 (4.7%) isolates mutations were detected in both gyrA and rrs genes. Its concordance with MGIT-960 culture drug susceptibility testing (DST) was 97% and 94.1%, 93.5%, 60.5% and 50% for the detection of XDR-TB, pre-XDR, Ethambutol, and Aminoglycosides/Cyclopeptides resistance. The Beijing lineage was predominant (46%) between both the pre-XDR/XDR-TB isolates. We conclude that MTBDRsl is useful for rapid detection of SLD resistance. Also in pre-XDR and XDR-TB isolates the frequency of relevant genetic mutations was significantly higher in the Beijing strains.

Second-line anti-tuberculosis drug resistance testing in Ghana identifies the first extensively drug-resistant tuberculosis case.

BackgroundDrug resistance surveillance is crucial for tuberculosis (TB) control. Therefore, our goal was to determine the prevalence of second-line anti-TB drug resistance among diverse primary drug-resistant Mycobacterium tuberculosis complex (MTBC) isolates in Ghana.Materials and methodsOne hundred and seventeen MTBC isolates with varying first-line drug resistance were analyzed. Additional resistance to second-line anti-TB drugs (streptomycin [STR], amikacin [AMK] and moxifloxacin [MOX]) was profiled using the Etest and GenoType MTBDRsl version 2.0. Genes associated with resistance to AMK and MOX (gyrA, gyrB, eis, rrs, tap, whiB7 and tlyA) were then analyzed for mutation.ResultsThirty-seven (31.9%) isolates had minimum inhibitory concentration (MIC) values ≥2 µg/mL against STR while 12 (10.3%) isolates had MIC values ≥1 µg/mL for AMK. Only one multidrug-resistant (MDR) isolate (Isolate ID: TB/Nm 919) had an MIC value of ≥0.125 µg/mL for MOX (MIC = 3 µg/mL). This isolate also had the highest MIC value for AMK (MIC = 16 µg/mL) and was confirmed as resistant to AMK and MOX by the line probe assay GenoType MTBDRsl version 2.0. Mutations associated with the resistance were: gyrA (G88C) and rrs (A514C and A1401G).ConclusionOur findings suggest the need to include routine second-line anti-TB drug susceptibility testing of MDR/rifampicin-resistant isolates in our diagnostic algorithm.

Risk factors for extensive drug resistance in multidrug-resistant tuberculosis cases: a case-case study.

Identification of extensively drug-resistant tuberculosis (XDR-TB) may be delayed because of the lack of availability of molecular testing for second-line drugs (SLDs). Early suspicion of XDR-TB is therefore necessary to avoid developing further drug resistance. To identify the characteristics associated with XDR-TB among multidrug-resistant TB (MDR-TB) cases before the availability of second-line drug susceptibility testing (DST) results. All MDR-TB cases with available second-line DST results recorded in France from 1998 to 2013 were classified as simple MDR-TB (no resistance to fluoroquinolones [FQs] or second-line injectable drugs [SLIDs]), pre-XDR-TB (resistance to FQs or SLIDs) and XDR-TB cases (resistance to both). A total of 833 MDR-TB cases were analysed, including 168 (20%) pre-XDR and 62 (7%) XDR-TB cases. A previous history of treatment was acknowledged among 41% of the cases; 12% were human immunodeficiency virus-positive. Characteristics independently associated with XDR-TB were foreign birth (OR 9.5), previous anti-tuberculosis treatment (OR 2.6), smear positivity (OR 4.5) and ethambutol (EMB) resistance (OR 9.1). Characteristics independently associated with pre-XDR-TB compared to simple MDR-TB cases were male sex (OR 1.6), birth in Europe (OR 2.6) and EMB resistance (OR 1.9). The presence of clinical or bacteriological characteristics associated with XDR-TB should lead to rapid molecular testing for resistance to SLDs before starting tailored treatment.

Mycobacterial genomic DNA from used Xpert MTB/RIF cartridges can be utilised for accurate second-line genotypic drug susceptibility testing and spoligotyping

Xpert MTB/RIF (Xpert) is a widely-used test for tuberculosis (TB) and rifampicin-resistance. Second-line drug susceptibility testing (DST), which is recommended by policymakers, typically requires additional specimen collection that delays effective treatment initiation. We examined whether cartridge extract (CE) from used Xpert TB-positive cartridges was, without downstream DNA extraction or purification, suitable for both genotypic DST (MTBDRplus, MTBDRsl), which may permit patients to rapidly receive a XDR-TB diagnosis from a single specimen, and spoligotyping, which could facilitate routine genotyping. To determine the limit-of-detection and diagnostic accuracy, CEs from dilution series of drug-susceptible and -resistant bacilli were tested (MTBDRplus, MTBDRsl). Xpert TB-positive patient sputa CEs (n = 85) were tested (56 Xpert-rifampicin-susceptible, MTBDRplus and MTBDRsl; 29 Xpert-rifampicin-resistant, MTBDRsl). Spoligotyping was done on CEs from dilution series and patient sputa (n = 10). MTBDRplus had high non-valid result rates. MTBDRsl on CEs from dilutions ≥103CFU/ml (CT ≤ 24, >“low” Xpert semiquantitation category) was accurate, had low indeterminate rates and, on CE from sputa, highly concordant with MTBDRsl isolate results. CE spoligotyping results from dilutions ≥103CFU/ml and sputa were correct. MTBDRsl and spoligotyping on CE are thus highly feasible. These findings reduce the need for additional specimen collection and culture, for which capacity is limited in high-burden countries, and have implications for diagnostic laboratories and TB molecular epidemiology.