Postprandial hypoglycemia caused by the combination of clarithromycin and rifampicin in a patient with nontuberculous mycobacterial pulmonary disease.

Most cases of nontuberculous mycobacterial pulmonary disease (NTM-PD) have a progressive clinical course, and initiation of treatment is recommended rather than watchful waiting. The NTM-PD medications are frequently associated with adverse reactions, occasionally serious. Optimization of the methods for monitoring and managing adverse events in NTM-PD treatment is thus an important medical issue. Here we report a first case of postprandial hypoglycemia caused by the combination of clarithromycin (CAM) and rifampicin (RFP) in a patient with NTM-PD. A 73-year-old Japanese woman with NTM-PD was hospitalized for treatment with a combination of oral CAM, RFP, and ethambutol. She took the first doses of antibiotics before breakfast, and 3 h later went into a hypoglycemic state. Postprandial hypoglycemia occurred with high reproducibility and was accompanied by relative insulin excess. Continuous glucose monitoring with or without food and in combination with various patterns of medication revealed that the combination of CAM and RFP specifically induced postprandial hypoglycemia. Shifting the timing of administration of the CAM and RFP combination from morning to before sleep corrected the hypoglycemia and enabled continuation of the antimicrobial treatment. In conclusion, our report suggests the importance of introducing NTM-PD medication under inpatient management in order to closely monitor and early detect postprandial hypoglycemia and other serious adverse events.

Mycobacterium tuberculosis and rifampicin-resistant tuberculosis among tuberculosis presumptive patients in selected zones of Tigray, Northern Ethiopia, 2016-2019.

Introduction: Tuberculosis (TB) is the second leading cause of mortality from an infectious disease worldwide. Multidrug-resistant tuberculosis (MDR-TB), where rifampicin-resistant TB is the biggest contributor, remains a global health threat. There is scant data on MTB and rifampicin resistance (RR-MTB) using Gene Xpert MTB/RIF assay in Ethiopia. This study aimed to determine the prevalence of MTB and RR-MTB among presumptive TB patients in Tigray, Northern Ethiopia. Methods: A multi-center retrospective cross-sectional study was conducted from October 2019 to December 2019 among presumptive MTB patients from four hospitals in Tigray. Records of sputum sample results of presumptive MTB patients analyzed with Gene Xpert MTB/RIF assay from January 2016 to December 2019 were investigated. Data were extracted using a data-extraction tool from registration books and analyzed using SPSS ver.21. Statistically significant was set at p-value ≤0.05. Results: From 17,329 presumptive adult MTB patients who had submitted sputum samples for TB diagnosis, 16,437 (94.9 %) had complete records and were included in the study. More than half (60.2 %) of them were males and ages ranged from 18 to 98 years. Majority of the participants: 15,047(91.5 %) were new cases and 11,750 (71.5 %) were with unknown HIV status. Prevalence of MTB was 9.7 % (95 % CI: 9.2-10.2 %) of these, rifampicin resistant-MTB was 8.7 % (95 % CI: 7.32-10.09 %). Age (being >29 years) [p < 0.001] and new cases [AOR = 0.46; 95%CI = 0.39, 0.53, p < 0.001] were associated with low TB infection. Age groups of 18-29 years were associated with higher RR-MTB [AOR = 3.08; 95 % CI = 1.07, 8.72, p = 0.036]. Conclusion: Nearly one-tenth of the presumptive tuberculosis patients tested positive for MTB; out of these, 8.7 % were RR-MTB. The high prevalence of TB and RR-MTB at a young age and previously treated cases calls for a concerted effort to improve and monitor TB treatment to reduce the problem.

Surveillance of fluoroquinolones resistance in rifampicin-susceptible tuberculosis in eastern China with whole-genome sequencing-based approach.

Background: Leveraging well-established DNA-level drug resistance mechanisms, whole-genome sequencing (WGS) has emerged as a valuable methodology for predicting drug resistance. As the most effective second-line anti-tuberculosis (anti-TB) drugs, fluoroquinoloness (FQs) are generally used to treat multidrug-resistant tuberculosis (MDR-TB, defined as being resistant to resistant to rifampicin and isoniazid) or rifampicin-resistant tuberculosis (RR-TB). However, FQs are also commonly used in the management of other bacterial infections. There are few published data on the rates of FQs resistance among rifampicin-susceptible TB. The prevalence of FQs resistance among TB patients who are rifampicin-susceptible has not been studied in Zhejiang Province, China. The goal of this study was to provide a baseline characterization of the prevalence of FQs resistance, particularly among rifampicin-susceptible TB in Zhejiang Province, China. Methods: Based on WGS, we have investigated the prevalence of FQs resistance among rifampicin-susceptible TB in Zhejiang Province. All pulmonary TB patients with positive cultures who were identified in Zhejiang area during TB drug resistance surveillance from 2018 to 2019 have enrolled in this population-based retrospective study. Results: The rate of FQs resistance was 4.6% (32/698) among TB, 4.0% (27/676) among rifampicin-susceptible TB, and 22.7% (5/22) among RR-TB. According to WGS, strains that differ within 12 single-nucleotide polymorphisms (SNPs) were considered to be transmission of FQ-resistant strains. Specifically, 3.7% (1/27) of FQs resistance was caused by the transmission of FQs-resistant strains among the rifampicin-susceptible TB and 40.7% (11/27) of FQs resistance was identified as hetero-resistance. Conclusion: The prevalence of FQs resistance among TB patients who were rifampicin-susceptible was severe in Zhejiang. The emergence of FQs resistance in TB isolates that are rifampicin-susceptible was mainly caused by the selection of drug-resistant strains. In order to prevent the emergence of FQs resistance, the WGS-based surveillance system for TB should be urgently established, and clinical awareness of the responsible use of FQs for respiratory infections should be enhanced.

Inhibition of porcine reproductive and respiratory syndrome virus replication by rifampicin in vitro.

Porcine reproductive and respiratory syndrome virus (PRRSV) continues to cause significant economic losses to the global swine industry, yet effective prevention and control measures remain elusive. The development of novel antivirals is thus urgently needed. Rifampicin (RFP), a semisynthetic derivative of rifamycin, has been previously reported to inhibit the replication of certain mammalian DNA viruses as well as RNA viruses. In this study, we unveil RFP as a potent inhibitor of PRRSV both in Marc-145 cells (half-maximal inhibitory concentration 61.26 µM) and porcine alveolar macrophages (half-maximal inhibitory concentration 53.09 µM). The inhibitory effect of RFP occurred during viral replication rather than binding, internalization and release. We also demonstrated that RFP inhibits PRRSV proteins production in the early stage of infection, without inhibiting host protein synthesis. Moreover, RFP effectively restricted porcine epidemic diarrhea virus (PEDV) and porcine enteric alphacoronavirus (PEAV) infection in Vero cells. In summary, these findings indicate the promising potential of RFP as a therapeutic agent for PRRSV, PEDV and PEAV infection in pig farms.

First detection of a Mycobacterium tuberculosis XDR clinical isolate harbouring an RpoB I491F mutation in a Ukrainian patient treated in Germany, October 2023.

This report documents the case of a Ukrainian patient infected with an extensively drug-resistant (XDR) lineage 2 Mycobacterium tuberculosis strain harbouring the rifampicin resistance mutation RpoB I491F. This mutation is not detected by routine molecular WHO-recommended rapid diagnostics, complicating the detection and treatment of these strains. The occurrence of such mutations underscores the need for enhanced diagnostic techniques and tailored treatment regimens, especially in eastern Europe where lineage 2 strains and XDR-tuberculosis are prevalent.

Enhanced detection of rifampicin and isoniazid resistance in mycobacterium tuberculosis using AuNP-qPCR: a rapid and accurate method.

OBJECTIVES: To evaluate the resistance of Mycobacterium tuberculosis to Rifampicin (RIF) and Isoniazid (INH) using enhanced qPCR methodologies. METHODS: This study compared the detection of drug-resistant mutations in the rpoB and katG genes using AuNP-qPCR and No-AuNP-qPCR. Calibration curves were constructed to correlate the amount of template with the Ct values for resistant strains. RESULTS: The AuNP-qPCR method demonstrated high efficacy in detecting RIF resistance with an area under the curve (AUC) of 0.951, sensitivity of 97.92%, specificity of 87.5%, and overall accuracy of 95.31%. Similarly, INH resistance detection by AuNP-qPCR showed an AUC of 0.981, sensitivity of 98.08%, specificity of 94.44%, and accuracy of 97.14%. Comparatively, No-AuNP-qPCR yielded lower performance metrics for RIF resistance (AUC: 0.867, sensitivity: 91.67%, specificity: 75%, accuracy: 87.5%) and INH resistance (AUC: 0.882, sensitivity: 88.46%, specificity: 83.33%, accuracy: 87.14%). CONCLUSIONS: AuNP-qPCR exhibits over traditional qPCR methods, making it a promising tool for rapid and precise detection of drug resistance in Mycobacterium tuberculosis. This method's robust performance underscores its potential to improve diagnostic protocols and contribute to more effective management of tuberculosis treatment.

TB and poverty: the effect of rifampicin-resistant TB on household income.

SETTING: The Republic of Moldova, one of Europe's poorest countries, also bears one of the highest burdens of rifampicin-resistant TB (RR-TB). OBJECTIVES: To trace the patients' journey through TB in terms of the relationship with poverty and assess its determinants. DESIGN: This cross-sectional study used secondary data from a survey assessing catastrophic costs in RR-TB-affected households. RESULTS: Data were obtained from 430 RR-TB patients. The percentage of poor TB-affected households rose from 65% prior to TB to 86% after TB treatment completion (P < 0.001). Social factors leading to poverty were identified for each stage: diagnostic period (history of incarceration: cOR 2.3, 95% CI 1.1-5.2); treatment period (being unemployed or unofficially employed: cOR 6.7, 95% CI 4.3-10.0); and post-treatment (being married or cohabiting: cOR 5.7, 95% CI 2.9-11.0). Participants who had ≥3 members in their households were more likely to be poor at all TB stages: diagnostic period (cOR 5.7, 95% CI 3.7-8.8), treatment period (cOR 3.8, 95% CI 2.5-5.6) and post-treatment (cOR 7.2, 95% CI 3.6-14.3). CONCLUSION: The study identified risk factors associated with poverty at each stage of TB. These findings outline that innovative social protection policies are required to protect TB patients against poverty.

CONTEXTE: La République de Moldavie est l'un des pays les plus pauvres d'Europe et l'un des plus touchés par la TB résistante à la rifampicine (RR-TB). OBJECTIFS: Nous avons cartographié le parcours des patients atteints de TB en lien avec la pauvreté et évalué les déterminants associés. MÉTHODE: Cette étude transversale a analysé des données secondaires issues d'une enquête évaluant les coûts catastrophiques supportés par les ménages touchés par la RR-TB. RÉSULTATS: Des données ont été recueillies auprès de 430 patients atteints de RR-TB. Le taux de ménages pauvres touchés par la TB est passé de 65% avant le traitement à 86% après la fin du traitement de la TB (P < 0,001). Pour chaque stade de la TB, les facteurs sociaux conduisant à la pauvreté ont été identifiés : période de diagnostic (antécédents d'emprisonnement : rapport de cotes brut (cOR) 2,3, IC à 95% 1,1­5,2) ; période de traitement (être au chômage ou employé officieux : cOR 6,7 ; IC 95% 4,3­10,0) ; et post-traitement (être marié ou cohabitant : cOR 5,7, IC 95% 2,9­11,0). Les participants dont le ménage comptait ≥3 membres étaient plus susceptibles d'être pauvres à tous les stades de la TB : période de diagnostic (cOR 5,7 ; IC à 95% 3,7­8,8), période de traitement (cOR 3,8 ; IC à 95% 2,5­5,6) et post-traitement (cOR 7,2 ; IC à 95% 3,6­14,3). CONCLUSION: L'étude a permis d'identifier des facteurs de risque liés à la pauvreté à toutes les étapes de la TB. Ces résultats soulignent l'importance de mettre en place des politiques de protection sociale novatrices pour prévenir l'appauvrissement des patients atteints de TB.

Metformin reduces the risk of poor treatment outcomes among individuals with rifampicin-resistant tuberculosis and type-2 diabetes mellitus.

We conducted a retrospective cohort study among individuals with rifampicin-resistant tuberculosis and diabetes to determine the association between metformin use and tuberculosis treatment outcomes. We found that individuals with metformin use had a significantly lower risk of poor tuberculosis treatment outcomes (adjusted RR=0.25, 95%CI 0.06 - 0.95) compared to those without.

Operational research as a mechanism to improve treatment outcomes for drug-resistant TB in the WHO European Region.

In 2022, the WHO European Region accounted for 15.1% of all incident rifampicin-resistant/multidrug-resistant TB (RR/MDR-TB) cases. Most occurred in 18 high-priority countries of eastern Europe and central Asia, many of which joined an initiative led by the WHO Regional Office for Europe. The aim was to introduce three, fully oral, 9-month modified shorter treatment regimens (mSTR) to treat RR/MDR-TB under operational research conditions. The three regimens were: 1) bedaquiline + linezolid + levofloxacin + clofazimine + cycloserine (BdqLzdLfxCfzCs); 2) BdqLzdLfxCfz + delamanid (Dlm) for children over 6 years of age and adults; and 3) DlmLzdLfxCfz for children under 6 years of age. The project aimed to enhance treatment success, facilitate mSTR implementation, promote quality of care and build research capacity, while also contributing to global knowledge on all-oral mSTR use. Between April 2020 and June 2022, >2,800 patients underwent mSTR treatment in the WHO European Region. This unique experience promoted further collaboration with national tuberculosis programmes, health authorities, experts and donors within and outside Europe, with a focus on implementing operational research and improving the quality of care in high TB burden countries of the region. In the hope of encouraging others to adopt this model, we have described the principles of the initiative, its strengths and weaknesses and next steps.

En 2022, la Région européenne de l'OMS a recensé 15,1% de l'ensemble des cas de TB résistante à la rifampicine/multirésistante aux médicaments (RR/MDR-TB). La majorité de ces cas ont eu lieu dans 18 pays hautement prioritaires d'Europe orientale et d'Asie centrale, parmi lesquels de nombreux ont adhéré à une initiative dirigée par le Bureau régional de l'OMS pour l'Europe. L'objectif était de mettre en place trois schémas thérapeutiques modifiés plus courts de 9 mois, entièrement oraux, (mSTR, pour l'anglais "fully oral, 9-month modified shorter treatment regimens ¼) pour le traitement de la RR/MDR-TB dans le cadre d'une recherche opérationnelle. Ces trois schémas étaient les suivants 1) bédaquiline + linézolide + lévofloxacine + clofazimine + cyclosérine (BdqLzdLfxCfzCs) ; 2) BdqLzdLfxCfz + delamanid (Dlm) pour les enfants de plus de 6 ans et les adultes ; et 3) DlmLzdLfxCfz pour les enfants de moins de 6 ans. Le projet visait à améliorer l'efficacité des traitements, à faciliter l'application des mSTR, à promouvoir la qualité des soins et à renforcer les capacités de recherche, tout en contribuant aux connaissances mondiales sur l'utilisation des mSTR par voie orale. Entre avril 2020 et juin 2022, plus de 2 800 patients ont reçu un traitement par mSTR dans la Région Européenne de l'OMS. Cette expérience unique a encouragé la continuation de la collaboration avec les programmes nationaux de lutte contre la TB, les autorités sanitaires, les experts et les donateurs tant en Europe qu'à l'étranger. L'accent est mis sur la mise en œuvre de la recherche opérationnelle et l'amélioration de la qualité des soins dans les pays de la région où la TB est fortement prévalente. Nous avons détaillé les principes de l'initiative, ses avantages et ses inconvénients, dans l'espoir d'inciter d'autres pays à suivre cet exemple, tout en exposant les étapes à venir.

A case of treatment for pulmonary infection caused by multidrug-resistant Acinetobacter baumannii.

Acinetobacter baumannii is a major pathogen in hospital-acquired infections notorious for its strong acquired resistance and complex drug resistance mechanisms. Owing to the lack of effective drugs, the mortality rate of extensively drug-resistant A. baumannii pneumonia can reach as high as 65%. This article analyzes a case where a combination of cefoperazone-sulbactam, polymyxin B, and minocycline with rifampicin successfully treated XDR-AB pulmonary infection. Combination therapy is effective and has a particular clinical value.

A Microtiter Plate Assay at Acidic pH to Identify Potentiators that Enhance Pyrazinamide Activity Against Mycobacterium tuberculosis.

Pyrazinamide (PZA) is a key component of chemotherapy for the treatment of drug-susceptible tuberculosis (TB) and is likely to continue to be included in new drug combinations. Potentiation of PZA could be used to reduce the emergence of resistance, shorten treatment times, and lead to a reduction in the quantity of PZA consumed by patients, thereby reducing the toxic effects. Acidified medium is required for the activity of PZA against Mycobacterium tuberculosis. In vitro assessments of pyrazinamide activity are often avoided because of the lack of standardization, which has led to a lack of effective in vitro tools for assessing and/or enhancing PZA activity.We have developed and optimized a novel, robust, and reproducible, microtiter plate assay, that centers around acidity levels that are low enough for PZA activity. The assay can be applied to the evaluation of novel compounds for the identification of potentiators that enhance PZA activity. In this assay, potentiation of PZA is demonstrated to be statistically significant with the addition of rifampicin (RIF), which can, therefore, be used as a positive control. Conversely, norfloxacin demonstrates no potentiating activity with PZA and can be used as a negative control. The method, and the associated considerations, described here, can be adapted in the search for potentiators of other antimicrobials.

Biotransformation of rifampicin by Aspergillus niger and antimicrobial activity of proposed metabolites.

Drug biotransformation studies emerges as an alternative to pharmacological investigations of metabolites, development of new drug candidates with reduced investment and most efficient production. The present study aims to evaluate the capacity of biotransformation of rifampicin by the filamentous fungus Aspergillus niger ATCC 9029. After incubation for 312 h, the drug was metabolized to two molecules: an isomer (m/z 455) and the rifampicin quinone (m/z 821). The monitoring of metabolite formation was performed by high-performance liquid chromatography, followed by their identification through ultra-high-performance liquid chromatography coupled to tandem mass spectrometer. In vitro antimicrobial activity of the proposed metabolites was evaluated against Staphylococus aureus microorganism, resulting in the loss of inhibitory activity when compared with the standards, with minimum inhibitory concentration of 7.5 µg/ml. The significant biotransformation power of the ATCC 9029 strain of A. niger was confirmed in this study, making this strain a candidate for pilot studies in fermentation tanks for the enzymatic metabolization of the antimicrobial rifampicin. The unprecedented result allows us to conclude that the prospect of new biotransforming strains in species of anemophilic fungi is a promising choice.

Xpert MTB/XDR implementation in South Africa: cost outcomes of centralised vs. decentralised approaches.

INTRODUCTION: In South Africa, Xpert® MTB/RIF Ultra (Ultra) is the recommended diagnostic assay for TB with line-probe assays for first- (LPAfl) and second-line drugs (LPAsl) providing additional drug susceptibility testing (DST) for samples that were rifampicin-resistant (RR-TB). To guide implementation of the recently launched Xpert® MTB/XDR (MTB/XDR) assay, a cost-outcomes analysis was conducted comparing total costs for genotypic DST (gDST) for persons diagnosed with RR-TB considering three strategies: replacing LPAfl/LPAsl (centralised level) with MTB/XDR vs. Ultra reflex testing (decentralised level). Further, DST was performed using residual specimen following RR-TB diagnosis. METHODS: The total cost of gDST was determined for three strategies, considering loss to follow-up (LTFU), unsuccessful test rates, and specimen volume. RESULTS: For 2019, 9,415 persons were diagnosed with RR-TB. A 35% LTFU rate between RR-TB diagnosis and LPAfl/LPAsl-DST was estimated. Unsuccessful test rates of 37% and 23.3% were reported for LPAfl and LPAsl, respectively. The estimated total costs were $191,472 for the conventional strategy, $122,352 for the centralised strategy, and $126,838 for the decentralised strategy. However, it was found that sufficient residual volume for reflex MTB/XDR testing is a limiting factor at the decentralised level. CONCLUSION: Centralising the implementation of XDR testing, as compared to LPAfl/LPAsl, leads to significant cost savings.

INTRODUCTION: En Afrique du Sud, Xpert® MTB/RIF Ultra (Ultra) est le test de diagnostic recommandé pour la TB avec des tests par sonde de ligne pour les médicaments de première (LPAfl) et de deuxième ligne (LPAsl) fournissant des tests de sensibilité aux médicaments (DST) supplémentaires pour les échantillons résistants à la rifampicine (RR-TB). Afin d'orienter la mise en œuvre du test Xpert® MTB/XDR (MTB/XDR) récemment lancé, une analyse coûts-résultats a été réalisée en comparant les coûts totaux de la DST génotypique (gDST) pour les personnes diagnostiquées avec une RR-TB en tenant compte de trois stratégies : remplacer le LPAfl/LPAsl (niveau centralisé) par le MTB/XDR par rapport au test Ultra reflex (niveau décentralisé). De plus, l'heure d'été a été réalisée à l'aide d'un échantillon résiduel après le diagnostic de RR-TB. MÉTHODES: Le coût total de la gDST a été déterminé pour trois stratégies, en tenant compte de la perte de suivi (LTFU), des taux d'échec des tests et du volume d'échantillons. RÉSULTATS: En 2019, 9 415 personnes ont reçu un diagnostic de RR-TB. Un taux de LTFU de 35% entre le diagnostic de RR-TB et le diagnostic de LPAfl/LPAsl-DST a été estimé. Des taux d'échec de 37% et de 23,3% ont été signalés pour LPAfl et LPAsl, respectivement. Les coûts totaux estimés étaient de 191 472 dollars pour la stratégie conventionnelle, de 122 352 dollars pour la stratégie centralisée et de 126 838 dollars pour la stratégie décentralisée. Cependant, il a été constaté qu'un volume résiduel suffisant pour les tests réflexes MTB/XDR est un facteur limitant au niveau décentralisé. CONCLUSION: La centralisation de la mise en œuvre des tests XDR, par rapport à LPAfl/LPAsl, permet de réaliser d'importantes économies.

The Effect of Rifapentine and Rifampicin on Serum Voriconazole Levels Persist for 5 Days and 7 Days or More After Discontinuation in Tuberculosis Patients with Chronic Pulmonary Aspergillosis.

Purpose: Voriconazole, a first-line therapeutic agent for chronic pulmonary aspergillosis, is metabolized by the cytochrome 450 enzymes, specifically CYP2C19 and CYP3A4. Rifampicin and rifapentine act as inducers of the cytochrome P450 enzyme. The current study explored the potential drug interactions arising from the co-administration of voriconazole with either rifampicin or rifapentine, as well as the duration of this effect on serum voriconazole levels after discontinuation of rifampicin or rifapentine. Patients and Methods: A retrospective study was conducted in tuberculosis patients with chronic pulmonary aspergillosis. These patients underwent a combination therapy involving voriconazole and rifampicin or rifapentine, or they were treated with voriconazole after discontinuation of rifampicin or rifapentine. The serum concentrations of voriconazole at steady-state were monitored. Data on demographic characteristics and the serum voriconazole levels were used for statistical analyses. Results: A total of 124 serum voriconazole concentrations from 109 patients were included in the study. The average serum concentration of voriconazole fell below the effective therapeutic range in patients treated with both voriconazole and rifampicin or rifapentine. Notably the co-administration of rifapentine led to a substantial (>70%) decrease in serum voriconazole levels in two patients. Moreover, this interfering effect persisted for at least 7 days following rifampicin discontinuation, while it endured for 5 days or more after discontinuation of rifapentine. Conclusion: Concomitant use of voriconazole and rifampicin or rifapentine should be avoided, and it is not recommended to initiate voriconazole therapy within 5 or 7 days after discontinuation of rifapentine or rifampicin. Therapeutic drug monitoring not only provides a basis for the adjustment of clinical dose, but also serves as a valuable tool for identifying drug interactions.

Farnesoid X Receptor: Effective alleviation of rifampicin -induced liver injury.

Antituberculosis drugs induce pharmacologic cholestatic liver injury with long-term administration. Liver injury resulting from rifampicin is potentially related to the bile acid nuclear receptor Farnesoid X Receptor (FXR). To investigate this, cholestasis was induced in both wild-type (C57BL/6N) mice and FXR knockout (FXR-null) mice through administration of rifampicin (200 mg/kg) via gavage for 7 consecutive days. Compared with C57BL/6N mice, FXR-null mice exhibited more severe liver injury after rifampicin administration, characterized by enlarged liver size, elevated transaminases, and increased inflammation. Moreover, under rifampicin treatment, FXR knockout impairs lipid secretion and exacerbates hepatic steatosis. Significantly, the expression of metabolism molecules BSEP increased, while NTCP and CYP7A1 decreased following rifampicin administration in C57BL/6N mice, whereas these changes were absent in FXR knockout mice. Furthermore, rifampicin treatment in both C57BL/6N and FXR-null mice was associated with elevated c-Jun N-terminal kinase phosphorylation (p-JNK) levels, with a more pronounced elevation in FXR-null mice. Our study suggests that rifampicin-induced liver injury, steatosis, and cholestasis are associated with FXR dysfunction and altered bile acid metabolism, and that the JNK signaling pathway is partially implicated in this injury. Based on these results, we propose that FXR might be a novel therapeutic target for addressing drug-induced liver injury.

Evaluation of genetic correlation with fluoroquinolones resistance in rifampicin-resistant Mycobacterium tuberculosis isolates.

Objective: To detect levofloxacin (LFX) and moxifloxacin (MFX) resistance among rifampicin-resistant tuberculosis (RR-TB) isolates, and predict the resistance level based on specific mutations in gyrA and gyrB genes. Methods: A total of 686 RR-TB isolates were collected from Chinese Drug Resistance Surveillance Program from 2013 to 2020. The minimum inhibitory concentrations (MICs) of 12 anti-TB drugs were acquired using the broth microdilution method, followed by whole genome sequencing (WGS) analysis. Results: Among the 686 RR isolates, the most prevalent resistance was to isoniazid (80.5 %) and ethambutol (28.4 %), followed by LFX (26.1 %) and MFX (21.9 %). The resistance rate of LFX (26.1%-99.4 %) was higher than that of MFX (21.9%-83.3 %) across various drug resistance patterns. Of the 180 fluoroquinolones (FQs) resistant isolates, 168 (93.3 %) had mutations in quinolone-resistant determining regions (QRDRs) with 21 mutation types, and Asp94Gly (32.7 %, 55/168) was the predominant mutation. Isolates with mutations in Asp94Asn and Asp94Gly were associated with high levels of resistance to LFX and MFX. Using broth microdilution method as gold standard, the sensitivities of WGS for LFX and MFX were 93.3 % and 98.0 %, and the specificities were 98.6 % and 95.0 %, respectively. Conclusion: The resistance rate of LFX was higher than that of MFX among various drug resistance patterns in RR-TB isolates. The gyrA Asp94Gly was the predominant mutation type underlying FQs resistance. However, no significant difference was observed between mutation patterns in gyrA gene and resistance level of FQs.

The (p)ppGpp synthetase Rsh promotes rifampicin tolerant persister cell formation in Brucella abortus by regulating the type II toxin-antitoxin module mbcTA.

Persister cells are transiently tolerant to antibiotics and are associated with recalcitrant chronic infections due to recolonization of host cells after antibiotic removal. Brucella spp. are facultative pathogens that establish intracellular infection cycles in host cells which results in chronic persistent infections. Brucella abortus forms multi-drug persister cells which are promoted by the (p)ppGpp synthetase Rsh during rifampicin exposure. Here, we confirmed that Rsh promoted persister cells formation in B. abortus stationary phase treated with rifampicin and enrofloxacin. Deletion of the gene for Rsh decreased persister cells level in the presence of these drugs in different growth phases. However, persister cells formation by deletion strain varied in different growth phases in the presence of other antibiotics. Rsh also was involved in persister cells formation during rifampicin treatment under certain stress conditions, including acidic conditions, exposure to PBS, and heat stress. Moreover, Rsh impacted persister cell levels during rifampicin or enrofloxacin treatment in RAW264.7 macrophages. Certain typeIItoxin-antitoxin modules were upregulated under various stress conditions in B. abortus. We established that Rsh positively regulated the type II toxin-antitoxin mbcTA. Moreover, rifampicin-tolerant persister cells formation was elevated and ATP levels were decreased when mbcTA promoter was overexpressed in Rsh deletion background in stationary phase. Our results establish that (p)ppGpp synthetase Rsh plays a key role in B. abortus persistence and may serve as a potent novel target in combination with rifampicin in the development of new therapeutic approaches and prevention strategies to treat chronic infections of Brucella.

Factors influencing false-positive results of rifampicin resistance detected by Xpert MTB/RIF: A retrospective study in Zhejiang, China.

Objective: This study aimed to explore the factors influencing false-positive results for rifampicin resistance (RIF-R) detected using Xpert MTB/RIF (Xpert). Methods: This retrospective analysis included the clinical data of patients from September 2019 to February 2023. The chi-square and rank sum tests were used to compare differences in patient characteristics between the true-positive and false-positive groups. Logistic regression was used to analyze the factors influencing false positives in the detection of RIF-R by Xpert. Results: A total of 384 patients were included. Logistic regression analysis revealed that, with mutation of probe E as the reference, mutations on probe A or C (OR = 72.68, P < 0.001), probe D (OR = 6.44, P < 0.001), and multiple probes (OR = 5.94, P = 0.002) were associated with false-positive results in Xpert detection of RIF-R. Taking probe delay ΔCt <4 as the reference, ΔCt (4-5.9) (OR = 13.54, P < 0.001), ΔCt (6-7.9) (OR = 48.08, P < 0.001) probe delays were associated with false positives in Xpert detection of RIF-R. When very low quantification is accompanied by a probe delay, the probability of false-positive RIF-R detection can reach 80 %. Conclusions: Clinicians should consider factors such as probe mutation type, probe delay, and very low quantification accompanied by probe delay when interpreting Xpert results, which can reduce the misdiagnosis of tuberculosis drug resistance.

Prevalence and Patterns of Drug-Resistant Mycobacterium tuberculosis in Newly Diagnosed Patients in China: A Systematic Review and Meta-Analysis.

BACKGROUND: Tuberculosis (TB), one of the deadliest infectious diseases globally, is increasingly exacerbated in China by the emergence of resistant Mycobacterium tuberculosis (MTB) strains. Drug-resistant TB, including mono-drug resistant TB, multidrug-resistant TB (MDR-TB), and extensively drug-resistant TB (XDR-TB), presents significant public health challenges. METHODS: We conducted a systematic literature review from January 2010 to February 2024 using databases such as PubMed, Embase, Web of Science, and Google Scholar. Our focus was on empirical data related to drug resistance patterns in newly diagnosed TB cases. Non-empirical studies were excluded through meticulous filtering. For meta-analysis, we used Review Manager (RevMan) 5.2 and assessed evidence quality using the Newcastle-Ottawa Scale (NOS). RESULTS: Our search strategy identified 40 studies that met the inclusion criteria, encompassing a total sample size of 87,667 participants. Among new TB cases, the estimated prevalence of MDR-TB in China was 6.9% (95% CI: 5.6-8.1%). Prevalence rates for mono-drug resistance to first-line anti-TB medications were as follows: isoniazid at 18.2% (95% CI: 16.4-20.6%), rifampicin at 10.5% (95% CI: 8.6-12.8%), and ethambutol at 5.7% (95% CI: 4.1-7.3%). The prevalence of streptomycin resistance, a former first-line anti-TB drug, was 17.1% (95% CI: 14.6-19.1%). The prevalence of other types of mono-drug resistance was 15.2% (95% CI: 13.9-17.3%), and for XDR-TB, it was 0.9% (95% CI: 0.6-1.4%). CONCLUSIONS: The high prevalence of drug-resistant TB in China poses a significant public health challenge. There is an urgent need for targeted interventions and continued surveillance to combat the spread of drug-resistant TB.