Genotypic and phenotypic comparison of drug resistance profiles of clinical multidrug-resistant Mycobacterium tuberculosis isolates using whole genome sequencing in Latvia.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) remains a major public health problem in many high tuberculosis (TB) burden countries. Phenotypic drug susceptibility testing (DST) take several weeks or months to result, but line probe assays and Xpert/Rif Ultra assay detect a limited number of resistance conferring gene mutations. Whole genome sequencing (WGS) is an advanced molecular testing method which theoretically can predict the resistance of M. tuberculosis (Mtb) isolates to all anti-TB agents through a single analysis. METHODS: Here, we aimed to identify the level of concordance between the phenotypic and WGS-based genotypic drug susceptibility (DS) patterns of MDR-TB isolates. Overall, data for 12 anti-TB medications were analyzed. RESULTS: In total, 63 MDR-TB Mtb isolates were included in the analysis, representing 27.4% of the total number of MDR-TB cases in Latvia in 2012-2014. Among them, five different sublineages were detected, and 2.2.1 (Beijing group) and 4.3.3 (Latin American-Mediterranean group) were the most abundant. There were 100% agreement between phenotypic and genotypic DS pattern for isoniazid, rifampicin, and linezolid. High concordance rate (> 90%) between phenotypic and genotypic DST results was detected for ofloxacin (93.7%), pyrazinamide (93.7%) and streptomycin (95.4%). Phenotypic and genotypic DS patterns were poorly correlated for ethionamide (agreement 56.4%), ethambutol (85.7%), amikacin (82.5%), capreomycin (81.0%), kanamycin (85.4%), and moxifloxacin (77.8%). For capreomycin, resistance conferring mutations were not identified in several phenotypically resistant isolates, and, in contrary, for ethionamide, ethambutol, amikacin, kanamycin, and moxifloxacin the resistance-related mutations were identified in several phenotypically sensitive isolates. CONCLUSIONS: WGS is a valuable tool for rapid genotypic DST for all anti-TB agents. For isoniazid and rifampicin phenotypic DST potentially can be replaced by genotypic DST based on 100% agreement between the tests. However, discrepant results for other anti-TB agents limit their prescription based solely on WGS data. For clinical decision, at the current level of knowledge, there is a need for combination of genotypic DST with modern, validated phenotypic DST methodologies for those medications which did not showed 100% agreement between the methods.

The differences in drug resistance between drug-resistant tuberculosis patients with and without diabetes mellitus in northeast China: a retrospective study.

BACKGROUND: Diabetes mellitus (DM) and drug-resistant tuberculosis (DR-TB) are serious global public health problems. This study aimed to explore the differences in drug resistance between DR-TB patients with and without DM. Risk factors for developing multidrug-resistant tuberculosis (MDR-TB) were also investigated among DR-TB patients. METHODS: The patient's basic demographic,　clinical characteristics, and drug susceptibility testing (DST) data were collected from the Chinese Disease Control Information System. Descriptive statistics were used to estimate the frequency and proportion of included variables. Categorical variables were compared using the Chi-square test or Fisher's exact test. Chi-square tests for trends were used to determine changes and trends in MDR-TB and pre-extensively drug-resistantTB (pre-XDR-TB) patterns over time. Univariate and multivariate logistic regression analysis was used to explore the risk factors of MDR-TB. RESULTS: Compared with DR-TB patients with DM, DR-TB patients without DM had significantly higher rates of mono-resistant streptomycin (SM) and any resistance to kanamycin (KM), but significantly lower rates of any resistance to protionamide (PTO) and mono-resistance to levofloxacin (LFX), and pre-XDR-TB (P<0.05). The proportion of resistance to other anti-TB drugs was not statistically different between the DR-TB with and without DM. Among DR-TB patients without and with DM, the proportion of patients with MDR-TB and pre-XDR-TB patterns showed a significant downward trend from 2016 to 2021 (P<0.05). Among DR-TB patients without DM, male, previously treated DR-TB cases, and immigration were risk factors for MDR-TB (P<0.05). In DR-TB patients with DM, a negative sputum smear is a risk factor for MDR-TB (P<0.05). CONCLUSION: There was no statistical difference in resistance patterns between DR-TB with and without DM, except in arbitrary resistance to PTO and KM, mono-resistant SM and LFX, and pre-XDR-TB. Great progress has been made in the prevention and control of MDR-TB and pre-XDR-TB. However, DR-TB patients with and without DM differ in their risk factors for developing MDR-TB.

Molecular Characterization of Resistance to Second-Line Anti-Mycobacterial Drugs among Clinical Isolates of Multidrug-Resistant Mycobacterium tuberculosis.

BACKGROUND: The emergence of multidrug resistance and extensively drug-resistant tuberculosis is a serious public health crisis. Using rapid and inexpensive molecular methods such as HRM assay in the detection of second-line drugs resistance in M. tuberculosis would be helpful in the treatment and control of XDR tuberculosis cases. METHODS: MDR-TB isolates were collected from Iranian tuberculosis laboratories. Drug susceptibility test performed via the indirect proportion method utilizing LJ Medium. Susceptibility to ciprofloxacin, ofloxacin, amikacin, kanamycin, and capreomycin, as second-line anti-tuberculosis agents were assessed. Single point mutations in gyrA, rrs and eis genes were detected via HRM assay and DNA sequencing. RESULTS: A DST test was performed for 56 MDR isolates and at least 27 (48.2%) isolates were resistant to CIP or OFL. Also, 14 (25%), 12 (21.4%), and 15 (26.7%) isolates were resistant to capreomycin, amikacin, and kanamycin, respectively. D94G, A90V, and G88C mutations were the most frequent mutations in gyrA gene. Also, A1401G mutation was detected more than the other mutations in rrs gene. CONCLUSIONS: The frequency of CIP/OFL and AMK/CAP/KAN-resistant TB is considerable among Iranian tuberculosis cases. HRM assay is a rapid and inexpensive test and can detect important mutation-based drug resistance in MDR-TB and XDR-TB isolates.

Prediction of drug resistance profile of multidrug-resistant Mycobacterium tuberculosis (MDR-MTB) isolates from newly diagnosed case by whole genome sequencing (WGS): a study from a high tuberculosis burden country.

OBJECTIVES: Our aim was to assess the ability of the Whole-genome sequencing (WGS) in predicting drug resistance profile of multidrug-resistant mycobacterium tuberculosis (MDR-MTB) from newly diagnosed cases in China. METHODS: We validated the Phenotypic drug Sensitivity Test (pDST) for 12 anti-tuberculosis drugs using the Bactec MGIT 960 system. We described the characteristics of the isolates enrolled and compared the pDST results with resistance profiles predicted by WGS. RESULTS: The pDST showed that of the 43 isolates enrolled, 25.6% were sensitive to rifabutin (RFB); 97.7%、97.7%、93.0% and 93.0% were sensitive to cycloserine (Cs), amikacin/kanamycin (Ak/Km), para-aminosalicylic acid (Pas) and ethionamide Eto), respectively; 18.6% were resistant to fluoroquinolones (FQs) or second-line injections. Genotype DST determined by WGS of Ak/Km、Eto and RFP reached high consistency to 97.7% compared with pDST, followed by moxifloxacin (Mfx) 95.3%, levofloxaci (Lfx) and Pas 93%, streptomycin (Sm) 90.3%. The genotype DST of RFB and EMB showed low consistency with the pDST of 67.2 and 79.1%. WGS also detected 27.9% isolates of pyrazinamide(PZA)-related drug-resistant mutation. No mutations associated with linezolid (Lzd), bedaquiline (Bdq) and clofazimine (Cfz) were detectd. CONCLUSIONS: WGS has the potential to infer resistance profiles without time-consuming phenotypic methods, which could be provide a basis to formulate reasonable treatment in high TB burden areas.

Detection of isoniazid, fluoroquinolone, ethionamide, amikacin, kanamycin, and capreomycin resistance by the Xpert MTB/XDR assay: a cross-sectional multicentre diagnostic accuracy study.

BACKGROUND: The WHO End TB Strategy requires drug susceptibility testing and treatment of all people with tuberculosis, but second-line diagnostic testing with line-probe assays needs to be done in experienced laboratories with advanced infrastructure. Fewer than half of people with drug-resistant tuberculosis receive appropriate treatment. We assessed the diagnostic accuracy of the rapid Xpert MTB/XDR automated molecular assay (Cepheid, Sunnyvale, CA, USA) to overcome these limitations. METHODS: We did a prospective study involving individuals presenting with pulmonary tuberculosis symptoms and at least one risk factor for drug resistance in four sites in India (New Delhi and Mumbai), Moldova, and South Africa between July 31, 2019, and March 21, 2020. The Xpert MTB/XDR assay was used as a reflex test to detect resistance to isoniazid, fluoroquinolones, ethionamide, amikacin, kanamycin, and capreomycin in adults with positive results for Mycobacterium tuberculosis complex on Xpert MTB/RIF or Ultra (Cepheid). Diagnostic performance was assessed against a composite reference standard of phenotypic drug-susceptibility testing and whole-genome sequencing. This study is registered with ClinicalTrials.gov, number NCT03728725. FINDINGS: Of 710 participants, 611 (86%) had results from both Xpert MTB/XDR and the reference standard for any drug and were included in analysis. Sensitivity for Xpert MTB/XDR detection of resistance was 94% (460 of 488, 95% CI 92-96) for isoniazid, 94% (222 of 235, 90-96%) for fluoroquinolones, 54% (178 of 328, 50-61) for ethionamide, 73% (60 of 82, 62-81) for amikacin, 86% (181 of 210, 81-91) for kanamycin, and 61% (53 of 87, 49-70) for capreomycin. Specificity was 98-100% for all drugs. Performance was equivalent to that of line-probe assays. The non-determinate rate of Xpert MTB/XDR (ie, invalid M tuberculosis complex detection) was 2·96%. INTERPRETATION: The Xpert MTB/XDR assay showed high diagnostic accuracy and met WHO's minimum target product profile criteria for a next-generation drug susceptibility test. The assay has the potential to diagnose drug-resistant tuberculosis rapidly and accurately and enable optimum treatment. FUNDING: German Federal Ministry of Education and Research through KfW, Dutch Ministry of Foreign Affairs, and Australian Department of Foreign Affairs and Trade.

Performance of GenoType MTBDRsl assay for detection of second-line drugs and ethambutol resistance directly from sputum specimens of MDR-TB patients in Bangladesh.

BACKGROUND: Rapid and early detection of drug susceptibility among multidrug-resistant tuberculosis (MDR-TB) patients could guide the timely initiation of effective treatment and reduce transmission of drug-resistant TB. In the current study, we evaluated the diagnostic performance of GenoType MTBDRsl (MTBDRsl) ver1.0 assay for detection of resistance to ofloxacin (OFL), kanamycin (KAN) and ethambutol (EMB), and additionally the XDR-TB among MDR-TB patients in Bangladesh. METHODS: The MTBDRsl assay was performed directly on 218 smear-positive sputum specimens collected from MDR-TB patients and the results were compared with the phenotypic drug susceptibility testing (DST) performed on solid Lowenstein-Jensen (L-J) media. We also analyzed the mutation patterns of gyrA, rrs, and embB genes for detection of resistance to OFL, KAN and EMB, respectively. RESULTS: The sensitivity and specificity of the MTBDRsl compared to phenotypic L-J DST were 81.8% (95% CI, 69.1-90.9) and 98.8% (95% CI, 95.6-99.8), respectively for OFL (PPV: 95.7% & NPV: 94.1%); 65.1% (95% CI, 57.5-72.2) and 86.7% (95% CI, 73.2-94.9), respectively for EMB (PPV: 94.9% & NPV: 39.4%); and 100% for KAN. The diagnostic accuracy of KAN, OFL and EMB were 100, 94.5 and 69.6%, respectively. Moreover, the sensitivity, specificity and diagnostic accuracy of MtBDRsl for detection of XDR-TB was 100%. The most frequently observed mutations were at codon D94G (46.8%) of gyrA gene, A1401G (83.3%) of rrs gene, and M306V (41.5%) of the embB gene. CONCLUSION: Considering the excellent performance in this study we suggest that MTBDRsl assay can be used as an initial rapid test for detection of KAN and OFL susceptibility, as well as XDR-TB directly from smear-positive sputum specimens of MDR-TB patients in Bangladesh.

Drug resistance gene mutations and treatment outcomes in MDR-TB: A prospective study in Eastern China.

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) poses a serious challenge to TB control. It is of great value to search for drug resistance mutation sites and explore the roles that they play in the diagnosis and prognosis of MDR-TB. METHODS: We consecutively enrolled MDR-TB patients from five cities in Jiangsu Province, China, between January 2013 and December 2014. Drug susceptibility tests of rifampin, isoniazid, ofloxacin, and kanamycin were routinely performed by proportion methods on Lowenstein-Jensen (LJ) medium. Drug resistance-related genes were sequenced, and the consistency of genetic mutations and phenotypic resistance was compared. The association between mutations and treatment outcomes was expressed as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Among 87 MDR-TB patients, 71 with treatment outcomes were involved in the analysis. The proportion of successful treatment was 50.7% (36/71). The rpoB gene exhibited the highest mutation rate (93.0%) followed by katG (70.4%), pncA (33.8%), gyrA (29.6%), eis (15.5%), rrs (12.7%), gyrB (9.9%) and rpsA (4.2%). Multivariable analysis demonstrated that patients with pncA gene mutations (adjusted OR: 19.69; 95% CI: 2.43-159.33), advanced age (adjusted OR: 13.53; 95% CI: 1.46-124.95), and nonstandard treatment (adjusted OR: 7.72; 95% CI: 1.35-44.35) had a significantly higher risk of poor treatment outcomes. CONCLUSIONS: These results suggest that Mycobacterium tuberculosis gene mutations may be related to phenotypic drug susceptibility. The pncA gene mutation along with treatment regimen and age are associated with the treatment outcomes of MDR-TB.

Accuracy of molecular drug susceptibility testing amongst tuberculosis patients in Karakalpakstan, Uzbekistan.

OBJECTIVES: In this retrospective study, we evaluated the diagnostic accuracy of molecular tests (MT) for the detection of DR-TB, compared to the gold standard liquid-based drug susceptibility testing (DST) in Karakalpakstan. METHODS: A total of 6670 specimens received in the Republican TB No 1 Hospital Laboratory of Karakalpakstan between January and July 2017 from new and retreatment patients were analysed. Samples were tested using Xpert MTB/RIF and line probe assays (LPA) for the detection of mutations associated with resistance. The sensitivity and specificity of MTs were calculated relative to results based on DST. RESULTS: The accuracy of MT for detection of rifampicin resistance was high, with sensitivity and specificity over 98%. However, we observed reduced sensitivity of LPA for detection of resistance; 86% for isoniazid (95% CI 82-90%), 86% for fluoroquinolones (95% CI 68-96%), 70% for capreomycin (95% CI 46-88%) and 23% for kanamycin (95% CI 13-35%). CONCLUSIONS: We show that MTs are a useful tool for rapid and safe diagnosis of DR-TB; however, clinicians should be aware of their limitations. Although detection of rifampicin resistance was highly accurate, our data suggest that resistance mutations circulating in the Republic of Karakalpakstan for other drugs were not detected by the methods used here. This merits further investigation.

Injectables' key role in rifampicin-resistant tuberculosis shorter treatment regimen outcomes.

BACKGROUND: Since a meta-analysis showed little or no effect of second-line injectables on treatment success, and using injectables may induce ototoxicity, injectable-free rifampicin-resistant tuberculosis (RR-TB) treatment regimens are recommended. However, acquired resistance preventing activity was overlooked. No previous study assessed the effect of shortening the duration of kanamycin administration to 2 months during the intensive phase of the RR-TB shorter treatment regimen (STR). METHODS: Retrospective cohort study of the effect of using 2 months of kanamycin instead of the standard 4(+) months (extension if lack of smear conversion at 4 months) on recurrence (either treatment failure or relapse) and fluoroquinolone acquired drug resistance, in patients treated with a gatifloxacin-based STR in Damien Foundation supported clinics in Bangladesh. Logistic regression was used to estimate associations. RESULTS: Five of 52 (9.6%) treated with a STR containing two months of kanamycin had recurrence, compared to 21 of 738 (2.8%) patients treated with the standard STR containing 4(+) months of kanamycin (OR 3.7; 95%CI:1.5-10.3). In those with initially fluoroquinolone-susceptible TB, acquired resistance to fluoroquinolone was detected in none of 639 patients treated with 4(+) months of kanamycin and two (4.5%) of 44 treated with two months of kanamycin (OR 75.2; 95%CI:3.6-1592.1). CONCLUSION: Two months of kanamycin was insufficient to prevent recurrence with acquired resistance to gatifloxacin, the core drug of the most effective RR-TB STR. Injectable mediated resistance prevention is important to reach high effectiveness, to safeguard all treatment options after recurrence, and to prevent the spread of resistant TB. Studies on all-oral regimens should also assess the effect of regimen composition on resistance acquisition. Until evidence shows that other drugs can assure at least the same strong resistance preventing activity of the injectables, it seems wise to continue using this group of drugs, and adapt the regimen if any ototoxicity is detected.

Ethionamide induced blue vision (cyanopsia): Case report.

Ethionamide is part of a group of drugs used in the treatment of drug resistant TB. With the advent of increasing drug resistance in pulmonary TB cases, use of Ethionamide, a second line anti tubercular drug is increasing. Vision changes are rare with ethionamide. Cyanopsia i.e., bluish tinted vision of surroundings with ethionamide is not known in literature. Here, we report a case of DRTB patient who developed cyanopsia soon after introducing ethionamide. Although reversible, ethionamide may sometimes need withdrawal because of significant distress caused to patient.

Irreversible neuropathy in extremely-drug resistant tuberculosis: An unfortunate clinical conundrum.

Drug-resistant tuberculosis is an increasing healthcare challenge. Drug regimen building demands the use of different therapeutic groups, many of which harbor neurotoxicity as a side-effect, whether central or peripheral. Peripheral neuropathy is a major concern as it tends to be severe and usually irreversible. Anti-tubercular drugs that may contribute to peripheral neuropathy include INH, ethambutol, linezolid, cycloserine and para-amino salicylic acid. This potential adverse effect must be balanced against the intrinsically grave prognosis that drug resistant tuberculosis harbors. We present such a clinically challenging case of a 25 years-old female with extremely drug resistant tuberculosis whose treatment necessitated the use of several neurotoxic anti-tubercular drugs, leading to severe sensory peripheral neuropathy who did not improve despite the withdrawal of culprit drugs. She developed positive and negative sensory symptoms in both lower limbs. Nerve conduction studies were suggestive of sensory neuropathy affecting both lower limbs. Alternate causes of peripheral neuropathy including HIV, vasculitis, B12 deficiency and diabetes were ruled out. Despite drug withdrawal, the patient did not improve significantly. This case emphasizes the irreversibility of anti-tubercular therapy-induced peripheral neuropathy, demanding more rigorous clinical screening for the same while managing such patients.

Case Report: Dynamics of Acquired Fluoroquinolone Resistance under Standardized Short-Course Treatment of Multidrug-Resistant Tuberculosis.

We report a case of acquired fluoroquinolone (FQ) resistance under short-course multidrug-resistant tuberculosis (MDR-TB) treatment. The patient was managed at Kabutare hospital, one of the two specialized MDR-TB clinics in Rwanda. A low dose of moxifloxacin was used in the first three critical months. Acquired resistance was identified at the ninth month of treatment, 3 months after stopping kanamycin in a strain initially susceptible only to FQs, kanamycin, and clofazimine. Fluoroquinolone resistance was detected in the same month by deep sequencing as routinely used second-line line probe assay and phenotypic drug susceptibility testing. High-dose FQ, preferably gatifloxacin, should be used to maximize effectiveness.

Sequence-based detection of first-line and second-line drugs resistance-associated mutations in Mycobacterium tuberculosis isolates in Isfahan, Iran.

Tuberculosis is an infectious disease, which requires special medical attention due to the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains. The present study aimed to assess drug resistance to first-line anti-mycobacterial drugs, including rifampin (RIF), isoniazid (INH), and ethambutol (EMB), as well as second-line drugs, including ofloxacin (OFX), kanamycin (KAN), amikacin (AMK), and capreomycin (CAP). The following eight loci were investigated to evaluate drug resistance: rpoB, katG, inhA, and embB, associated with resistance to RIF, INH, and EMB and gyrA, rrs, eis, and tlyA, associated with resistance to OFX, AMK, KAN, and CAP. A total of 482 patients with tuberculosis, who were referred to Molla Haadi Sabzevari Healthcare Center (Isfahan, Iran) during 2014-2017, were studied. Of 482 patients with tuberculosis, 32 (6.63%) Mycobacterium tuberculosis isolates were resistant to the first-line anti-mycobacterial drugs. Overall, 23 (71.8%), 13 (40.6%), and 3 (9.3%) isolates were resistant to INH, RIF, and EMB, respectively. Also, 13 (100%), 6 (46.1%), and 1 (7.6%) out of 13 MDR/RIF-resistant isolates were resistant to CAP and KAN, AMK, and OFX, respectively. Among the eight loci, non-synonymous substitutions were observed in rpoB (n = 7), katG (n = 10), inhA (n = 7), gyrA (n = 13), and rrs (n = 3), whereas synonymous substitutions were seen in tlyA and gyrA. On the other hand, no mutation was detected in embB or eis. Based on the present results, mutations in the eis promoter region and embB locus may not be involved in resistance to KAN and EMB in our study population. Also, the gyrA Asp94Asn mutation may be an indicator of resistance to OFX. We did not detect any XDR isolates, whereas MDR and pre-XDR isolates were found, which can be alarming.

Application of phage therapy: Synergistic effect of phage EcSw (ΦEcSw) and antibiotic combination towards antibiotic-resistant Escherichia coli.

Bacteriophage therapy is acknowledged as a potential tool to prevent or treat multidrug-resistant bacterial infections. In this study, our major focus was on the bacteriolytic activity of phage EcSw (ΦEcSw) against the emergence of the clinically important Escherichia coli Sw1 and E. coli O157:H7. The amount of the antibiotics was changed in a concentration-dependent manner, and the ΦEcSw susceptibility to antibiotics was determined. The kanamycin and chloramphenicol inhibited the titre of phage, but ampicillin did not show phage inhibition. Though the kanamycin and chloramphenicol controlled the growth of Sw1 in a concentration-dependent manner, the ampicillin did not due to the resistance. The combined activity of the ΦEcSw with antibiotics (kanamycin and chloramphenicol) compared with the antibiotics alone showed significant lytic activity p < .001). In addition, phage-based therapy was evaluated for controlling the multidrug-resistant E. coli Sw1 and E. coli O157:H7 in zebrafish and BALB/c mice, respectively. Our results provide novel advantages of phage therapy and phage-antibiotic therapy to control antibiotic-resistant bacteria.

Frequency and patterns of second-line resistance conferring mutations among MDR-TB isolates resistant to a second-line drug from eSwatini, Somalia and Uganda (2014-2016).

BACKGROUND: Pulmonary tuberculosis is a leading cause of morbidity and mortality in developing countries. Drug resistance, a huge problem in this contagious disease, is driven by point mutations in the Mycobacterium tuberculosis genome however, their frequencies vary geographically and this affects applicability of molecular diagnostics for rapid detection of resistance. Here, we report the frequency and patterns of mutations associated with resistance to second-line anti-TB drugs in multidrug-resistant (MDR) M. tuberculosis isolates from eSwatini, Somalia and Uganda that were resistant to a second-line anti-TB drug. METHODS: The quinolone resistance determining region (QRDR) of gyrA/gyrB genes and the drug resistance associated fragment of rrs gene from 80 isolates were sequenced and investigated for presence of drug resistance mutations. Of the 80 isolates, 40 were MDR, of which 28 (70%) were resistant to a second-line anti-TB injectable drug, 18 (45%) were levofloxacin resistant while 12 (30%) were extensively drug resistant (XDR). The remaining 40 isolates were susceptible to anti-TB drugs. MIRU-VNTR analysis was performed for M/XDR isolates. RESULTS: We successfully sub-cultured 38 of the 40 M/XDR isolates. The gyrA resistance mutations (Gly88Ala/Cys/Ala, Ala90Val, Ser91Pro, Asp94Gly/Asn) and gyrB resistance mutations (Asp500His, Asn538Asp) were detected in 72.2% (13/18) and 22.2% (4/18) of the MDR and levofloxacin resistant isolates, respectively. Overall, drug resistance mutations in gyrA/gyrB QRDRs occurred in 77.8% (14/18) of the MDR and levofloxacin resistant isolates. Furthermore, drug resistance mutations a1401g and g1484 t in rrs occurred in 64.3% (18/28) of the MDR isolates resistant to a second-line anti-TB injectable drug. Drug resistance mutations were not detected in drug susceptible isolates. CONCLUSIONS: The frequency of resistance mutations to second-line anti-TB drugs in MDR-TB isolates resistant to second line anti-TB drugs from eSwatini, Somalia and Uganda is high, implying that rapid molecular tests are useful in detecting second-line anti-TB drug resistance in those countries. Relatedly, the frequency of fluoroquinolone resistance mutations in gyrB/QRDR is high relative to global estimates, and they occurred independently of gyrA/QRDR mutations implying that their absence in panels of molecular tests for detecting fluoroquinolone resistance may yield false negative results in our setting.

Treatment Outcomes of Patients Switching From an Injectable Drug to Bedaquiline During Short Standardized Treatment for Multidrug-resistant Tuberculosis in Mozambique.

Bedaquiline was recommended by the World Health Organization as the preferred option in treatment of multidrug-resistant tuberculosis (MDR-TB) with long regimens. However, no recommendation was given for the short MDR-TB regimen. Data from our small cohort of patients who switched from injectable drug to bedaquiline suggest that a bedaquiline-based short regimen is effective and safe.

Nisin reduces uterine inflammation in rats by modulating concentrations of pro- and anti-inflammatory cytokines.

PROBLEM: The Staphylococcus aureus has been found to be associated with clinical endometritis of cow. The result of oral antibiotic remains poor. Therefore, this study investigates the role of nisin in endometritis. METHOD OF STUDY: The effect of nisin on the growth and cell wall of S aureus were determined in vitro. Besides the blank control group, animals with established post-partum were inoculated with 0.1 mL S aureus intravaginally. Two days post-inoculation, the animals were administered nisin (25 mg/kg), kanamycin (30 mg/kg), and water (model group) for 7 days. On the seventh day, serum and uterine organs were obtained for pro- and anti-inflammatory analysis. The uterine tissue samples were weighed, and histopathological analysis was performed. RESULTS: The results showed that nisin had an inhibitory effect on the growth and cell wall formation of S aureus. Nisin and kanamycin treatment prevented a S aureus-induced decrease in pro-inflammatory cytokines and promoted an increase in the level of serum anti-inflammatory cytokines in the endometrium of these animals. Nisin and kanamycin, significantly decreased (P < 0.05) the endometritis-induced increases in uterine weight, restored endometrial architecture and significantly (P < 0.05) normalized uterine neutrophils to control levels. Additionally, improved levels of B7-2 , IFN-γ, IL-2, and IL-8 were observed when treated with nisin. CONCLUSION: Our findings suggest that nisin compared favorably with kanamycin in endometritis prevention, suggesting that nisin can be used in S aureus-induced endometritis by protecting the uterus from S aureus infection.

Treatment correlates of successful outcomes in pulmonary multidrug-resistant tuberculosis: an individual patient data meta-analysis.

BACKGROUND: Treatment outcomes for multidrug-resistant tuberculosis remain poor. We aimed to estimate the association of treatment success and death with the use of individual drugs, and the optimal number and duration of treatment with those drugs in patients with multidrug-resistant tuberculosis. METHODS: In this individual patient data meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library to identify potentially eligible observational and experimental studies published between Jan 1, 2009, and April 30, 2016. We also searched reference lists from all systematic reviews of treatment of multidrug-resistant tuberculosis published since 2009. To be eligible, studies had to report original results, with end of treatment outcomes (treatment completion [success], failure, or relapse) in cohorts of at least 25 adults (aged >18 years). We used anonymised individual patient data from eligible studies, provided by study investigators, regarding clinical characteristics, treatment, and outcomes. Using propensity score-matched generalised mixed effects logistic, or linear regression, we calculated adjusted odds ratios and adjusted risk differences for success or death during treatment, for specific drugs currently used to treat multidrug-resistant tuberculosis, as well as the number of drugs used and treatment duration. FINDINGS: Of 12 030 patients from 25 countries in 50 studies, 7346 (61%) had treatment success, 1017 (8%) had failure or relapse, and 1729 (14%) died. Compared with failure or relapse, treatment success was positively associated with the use of linezolid (adjusted risk difference 0·15, 95% CI 0·11 to 0·18), levofloxacin (0·15, 0·13 to 0·18), carbapenems (0·14, 0·06 to 0·21), moxifloxacin (0·11, 0·08 to 0·14), bedaquiline (0·10, 0·05 to 0·14), and clofazimine (0·06, 0·01 to 0·10). There was a significant association between reduced mortality and use of linezolid (-0·20, -0·23 to -0·16), levofloxacin (-0·06, -0·09 to -0·04), moxifloxacin (-0·07, -0·10 to -0·04), or bedaquiline (-0·14, -0·19 to -0·10). Compared with regimens without any injectable drug, amikacin provided modest benefits, but kanamycin and capreomycin were associated with worse outcomes. The remaining drugs were associated with slight or no improvements in outcomes. Treatment outcomes were significantly worse for most drugs if they were used despite in-vitro resistance. The optimal number of effective drugs seemed to be five in the initial phase, and four in the continuation phase. In these adjusted analyses, heterogeneity, based on a simulated I2 method, was high for approximately half the estimates for specific drugs, although relatively low for number of drugs and durations analyses. INTERPRETATION: Although inferences are limited by the observational nature of these data, treatment outcomes were significantly better with use of linezolid, later generation fluoroquinolones, bedaquiline, clofazimine, and carbapenems for treatment of multidrug-resistant tuberculosis. These findings emphasise the need for trials to ascertain the optimal combination and duration of these drugs for treatment of this condition. FUNDING: American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Risk of Nephrotoxicity in Patients With Drug-Resistant Tuberculosis Treated With Kanamycin/Capreomycin With or Without Concomitant Use of Tenofovir-Containing Antiretroviral Therapy.

BACKGROUND: The intersection of HIV and drug-resistant (DR) tuberculosis (TB) presents the challenge of managing convergent drug toxicities. METHODS: We conducted a retrospective study of adult patients with DR-TB treated with a kanamycin/capreomycin-based (KM) regimen, with or without concomitant antiretroviral therapy (ART). We estimated the incidence of nephrotoxicity (defined as an increase in serum creatinine greater than 26.5 µmol, or an increase in serum creatinine to 1.5 times the baseline value, or a decline in glomerular filtration rate to less than 60 mL/min/1.73 m), and evaluated the association between reported drug use and nephrotoxicity using Kaplan-Meier plots. RESULTS: A total of 215 patients with DR-TB were treated with a kanamycin/capreomycin-based regimen, with or without concomitant ART. The incidence rate of nephrotoxicity was 3.6 [95% confidence interval (CI): 1.4 to 7.3], 6.9 (95% CI: 5.2 to 9.0), and 12 (95% CI: 3.3 to 30.9) cases per 100 person-months of follow-up in the KM only group (n = 42), the KM + TDF (tenofovir disoproxil fumarate) group (n = 163), and the KM + Other ART group (n = 10), respectively. Using the KM only group as a reference, the hazard ratio was 2.06 (95% CI: 0.92 to 4.63) in the KM + TDF group, and 4.09 (95% CI: 1.17 to 14.25) in the KM + Other ART group. Advancing age was an independent predictor of nephrotoxicity (adjusted hazard ratio 1.29, 95% CI: 1.14 to 1.46). CONCLUSIONS: Our findings provide evidence of a significant risk of nephrotoxicity during treatment with a kanamycin/capreomycin-based DR-TB regimen, with or without concurrent treatment with ART. This study lends further support to calls for the substitution of TDF during the intensive phase of DR-TB treatment and for close monitoring of renal function during DR-TB treatment, especially in settings where the use of kanamycin/capreomycin is unavoidable.

Diagnostic accuracy of GenoType® MTBDRsl VER 2.0 in detecting second-line drug resistance to M. tuberculosis.

SETTING: A tertiary care hospital in North India. OBJECTIVE: To evaluate the GenoType® MTBDRsl VER 2.0 assay for rapid diagnosis of second-line drug resistance to Mycobacterium tuberculosis. DESIGN: The MTBDRsl VER 2.0 assay was performed on 431 multidrug-resistant M. tuberculosis clinical isolates and specimens. The results were compared with phenotypic drug susceptibility testing (DST) and DNA sequencing. Molecular characterisation of drug resistance using DNA sequencing was performed for gyrA, gyrB, rrs and eis. RESULTS: Of the 415 isolates, respectively 176 (42.4%) and 40 (9.6%) were resistant to levofloxacin (LVX) and kanamycin (KM). The sensitivity and specificity of MTBDRsl VER 2.0 compared with phenotypic DST in detecting LVX resistance were respectively 97.2% (95%CI 93.5-99.1) and 99.1% (95%CI 97-99.9), and for KM resistance they were respectively 92.5% (95%CI 79.6-98.4) and 99.5% (95%CI 98.1-99.9). CONCLUSION: The MTBDRsl VER 2.0 assay showed very high sensitivity and specificity for the detection of second-line drug resistance, suggesting it has potential for the rapid, early detection of such cases.