Rifampicin tolerance and growth fitness among isoniazid-resistant clinical Mycobacterium tuberculosis isolates from a longitudinal study.

Antibiotic tolerance in Mycobacterium tuberculosis reduces bacterial killing, worsens treatment outcomes, and contributes to resistance. We studied rifampicin tolerance in isolates with or without isoniazid resistance (IR). Using a minimum duration of killing assay, we measured rifampicin survival in isoniazid-susceptible (IS, n=119) and resistant (IR, n=84) isolates, correlating tolerance with bacterial growth, rifampicin minimum inhibitory concentrations (MICs), and isoniazid-resistant mutations. Longitudinal IR isolates were analyzed for changes in rifampicin tolerance and genetic variant emergence. The median time for rifampicin to reduce the bacterial population by 90% (MDK90) increased from 1.23 days (IS) and 1.31 days (IR) to 2.55 days (IS) and 1.98 days (IR) over 15-60 days of incubation, indicating fast and slow-growing tolerant sub-populations. A 6 log10-fold survival fraction classified tolerance as low, medium, or high, showing that IR is linked to increased tolerance and faster growth (OR = 2.68 for low vs. medium, OR = 4.42 for low vs. high, p-trend = 0.0003). High tolerance in IR isolates was associated with rifampicin treatment in patients and genetic microvariants. These findings suggest that IR tuberculosis should be assessed for high rifampicin tolerance to optimize treatment and prevent the development of multi-drug-resistant tuberculosis.

Delayed drug hypersensitivity to anti-tuberculosis drug: a new desensitization scheme.

Introduction: Tuberculosis is a communicable illness and one of the leading causes of death, especially in developing countries like Turkey. One of the problems that must be managed well in the treatment of tuberculosis is drug hypersensitivity. The first-line agents are very important for the success of treatment. Alternative drugs are more toxic and less successful in treatment. Therefore, it is very important to be able to include first-line drugs in the post-hypersensitivity regimen. At this point, the success of desensitization comes to the fore. There are fewer studies on rapid drug desensitization in delayed-type drug hypersensitivity to anti-tuberculosis drugs. Aim: The primary aim of the study was to determine the prevalence of delayed-type hypersensitivity reactions in drug-sensitive cases; the secondary aim was to determine the appropriate treatment management. Material and methods: This was a retrospective study. Demographic features, tuberculosis diagnostic indicator, clinical signs of developing a hypersensitivity reaction, reaction time, desensitization scheme and treatment were evaluated. Results: A total of 41 tuberculosis cases were included in the study. Twenty-six of the cases were male; mean age (mean ± SD) 55.44 ±16.93 years; 70.7% of them were diagnosed bacteriologically; 70.7% of them were diagnosed with pulmonary tuberculosis. The most common skin finding was maculopapular drug eruption. The development time (mean ± SD) of the reaction in patients who developed a reaction was 34.93 ±39.62 days. The responsible agent could be identified in 15 reactions. The most common drug responsible for the reaction was rifampicin. Successful desensitization was achieved in 19 (46.3%) cases with the sensitive regimen. The duration of treatment was 8.97 ±3.44 months. When evaluated in terms of treatment results, cure and treatment completion were accepted as treatment success. In this case, 30 (73.2%) patients successfully completed the treatment. Conclusions: Our study is one of the largest series in which delayed-type hypersensitivity develops under tuberculosis treatment and the desensitization scheme is recommended. A practical, easy desensitization scheme had been shared in this paper.

An aerosol nanocomposite microparticle formulation using Rifampicin-Cyclodextrin inclusion complexes for the treatment of pulmonary diseases.

Rifampicin (RIF) is commonly used in the treatment of tuberculosis (TB), a bacterium that currently infects one fourth of the world's population. Despite the effectiveness of RIF in treating TB, current RIF treatment regimens require frequent and prolonged dosing, leading to decreased patient compliance and, ultimately, increased mortality rates. This project aims to provide an alternative to oral RIF by means of an inhalable spray-dried formulation. TB uses alveolar macrophages to hide and replicate until the cells rupture, further spreading the bacteria. Therefore, delivering RIF directly to the lungs can increase the drug concentration at the site of infection while reducing off-site side effects. Cyclodextrin (CD) was used to create a RIF-CD inclusion complex to increase RIF solubility and biodegradable RIF-loaded NP (RIF NP) were developed to provide sustained release of RIF. RIF NP and RIF-CD inclusion complex were spray dried to form a dry powder nanocomposite microparticles (nCmP) formulation (RIF-CD nCmP). RIF-CD nCmP displayed appropriate aerosol dispersion characteristics for effective deposition in the alveolar region of the lungs (4.0 µm) with a fine particle fraction of 89 %. The nCmP provided both a burst release of RIF due to the RIF-CD complex and pH-sensitive release of RIF due to the RIF NP incorporated into the formulation. RIF-CD nCmP did not adversely affect lung epithelial cell viability and RIF NP were able to effectively redisperse from the nCmP after spray drying. These results suggest that RIF-CD nCmP can successfully deliver RIF to the site of TB infection while providing both immediate and sustained release of RIF. Overall, the RIF-CD nCmP formulation has the potential to improve the efficacy for the treatment of TB.

Evaluation of Diagnostic Methods and Rifampicin Resistance in Pulmonary Tuberculosis: A Hospital-Based Study.

Background Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, predominantly affecting the lungs (pulmonary TB) and is a significant public health challenge in India. The study aims to analyze demographic, radiological, and clinical subgroups of pulmonary TB cases, examine the relationship between smear acid-fast bacillus (AFB examination) and cartridge-based nucleic acid amplification test (CBNAAT), evaluate CBNAAT sensitivity for Mycobacterium tuberculosis (MTB) in new and previously treated patients, and determine the proportion of rifampicin resistance. Methods This hospital-based prospective study was conducted among patients diagnosed with pulmonary TB at the Respiratory Medicine Department of a Government Hospital over 16 months (August 2019 to December 2020). The study included 150 diagnosed TB cases (new and previously treated). Data collection encompassed demographic details, clinical symptoms, comorbidities, radiological findings (chest X-ray), and microbiological results (smear AFB examination, CBNAAT). Sputum samples were subjected to Ziehl-Neelsen staining and CBNAAT for MTB detection and rifampicin resistance testing. Statistical analysis was performed using IBM SPSS Statistics version 21.0 (IBM Corp., Armonk, NY, USA). Results Of the 150 patients, 69.3% were male, and 48% were aged 21-40 years. The majority had a BMI of 18.5-24.9 kg/m² (50%) and resided in urban areas (63.3%). Common symptoms included cough (95.3%), fever (80%), and weight loss (74%). Cavitary lesions on chest X-ray were observed in 84% of patients. Smear microscopy detected MTB in 72.7% of cases, while CBNAAT detected MTB in 94% of cases. CBNAAT sensitivity for smear-positive and smear-negative samples was 93.97% and 94.12%, respectively. Rifampicin resistance was found in 3% of new cases and 6% of previously treated cases. The sensitivity of smear microscopy was 77.33%, and the sensitivity of CBNAAT was 94%. Conclusion The study underscores the high burden of pulmonary TB and the utility of CBNAAT in detecting MTB and rifampicin resistance, particularly in smear-negative samples. The findings highlight the necessity of universal drug susceptibility testing (DST) for effective TB management and the importance of addressing drug resistance to improve treatment outcomes.

Tuberculosis in kidney transplant candidates and recipients.

Tuberculosis (TB) is the leading cause of infectious mortality and morbidity in the world, second only to coronavirus disease 2019. Patients with chronic kidney disease and kidney transplant recipients are at a higher risk of developing TB than the general population. Active TB is difficult to diagnose in this population due to close mimics. All transplant candidates should be screened for latent TB infection and given TB prophylaxis. Patients who develop active TB pre- or post-transplantation should receive multidrug combination therapy of antitubercular therapy for the recommended duration with optimal dose modification as per glomerular filtration rate.

Lead-Free Cs2AgBiBr6/TiO2 S-Scheme Heterojunction for Efficient Photocatalytic Antibiotic Rifampicin Degradation.

Exploring efficient and stable halide perovskite-based photocatalysts is a great challenge due to the balance between the photocatalytic performance, toxicity, and intrinsic chemical instability of the materials. Here, the environmentally friendly lead-free perovskite Cs2AgBiBr6 confined in the mesoporous TiO2 crystal matrix has been designed to enhance the charge carrier extraction and utilization for efficient photocatalytic rifampicin degradation. The as-prepared Cs2AgBiBr6/TiO2 catalyst was stable in air for over 500 days. An S-scheme heterojunction was formed between the (004) plane of Cs2AgBiBr6 and the (101) plane of TiO2 through the Bi-O-Br bonds. The built-in electric field at the interface efficiently promoted the photoinduced charge separation and carrier extraction. The Cs2AgBiBr6/TiO2-200 showed a 92.83% degradation efficiency of rifampicin within 80 min under simulated sunlight illumination (AM 1.5G 100 mW cm-2). This work offers an effective way for the construction of halide perovskite-based photocatalysts with high photocatalytic performance, good stability, and low toxicity simultaneously.

Plasma and urinary CP I and CP III concentrations in chimeric mice with human hepatocytes after rifampicin administration.

The interest in transporter-mediated drug interactions has been increasing in the field of drug development. In this study, we measured the plasma and urinary concentrations of coproporphyrin (CP) I and CP III as endogenous substrates for organic anion-transporting polypeptide (OATP) using chimeric mice with human hepatocytes (PXB mice) and examined the influence of an OATP inhibitor, rifampicin (RIF). CP I and CP III were actively taken up intracellularly, and RIF inhibited the uptake in a concentration-dependent manner for both CP I and CP III in human hepatocytes (PXB-cells). Single doses of RIF at 10 and 30 mg/kg were orally or intravenously administered to PXB mice and wild-type ICR mice. Plasma concentrations (AUC0-8h) of CP I increased in both mice. However, a marked increase in CP III was only observed in ICR mice, after intravenous administration of RIF at 30 mg/kg. The IC50 values of RIF for intracellular CP I/III uptake and the unbound plasma concentrations of RIF suggested that the increase in plasma CP I is associated with the exposure of RIF to OATPs. The 24-h cumulative urinary excretions of CP I and CP III increased in both mice, but more markedly in PXB mice. Thus, RIF increased the plasma and urinary concentrations of CP I and CP III in the mice, as reported in humans, and CP I may be a more sensitive biomarker of OATP-mediated drug interactions in PXB mice.

Clinical profiles of multidrug-resistant and rifampicin-monoresistant tuberculosis in Korea, 2018-2021: a nationwide cross-sectional study.

BACKGROUND: This study aimed to identify the clinical characteristics of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) in the Republic of Korea. METHODS: Data of notified people with tuberculosis between July 2018 and December 2021 were retrieved from the Korea Tuberculosis Cohort database. MDR/RR-TB was further categorized according to isoniazid susceptibility as follows: (1) MDR-TB, (2) rifampicin-monoresistant tuberculosis (RMR-TB), and (3) RR-TB if susceptibility to isoniazid was unknown. Multivariable logistic regression analysis was conducted to identify the factors associated with MDR/RR-TB. RESULTS: Between 2018 and 2021, the proportion of MDR/RR-TB cases among all TB cases and TB cases with known drug susceptibility test results was 2.1% (502/24,447). The proportions of MDR/RR-TB and MDR-TB cases among TB cases with known drug susceptibility test results were 3.3% (502/15,071) and 1.9% (292/15,071), respectively. Among all cases of rifampicin resistance, 31.7% (159/502) were RMR-TB and 10.2% (51/502) were RR-TB. Multivariable logistic regression analyses revealed that younger age, foreigners, and prior tuberculosis history were significantly associated with MDR/RR-TB. CONCLUSION: Rapid identification of rifampicin resistance targeting the high-risk populations, such as younger generations, foreign-born individuals, and previously treated patients are necessary for patient-centered care.

Assessing Hepatotoxicity in Novel and Standard Short Regimens for Rifampicin-Resistant Tuberculosis: Insights from the TB-TRUST and TB-TRUST -plus Trials.

BACKGROUND: Efforts to shorten rifampicin-resistant tuberculosis (RR-TB) treatment have led to concerns about hepatotoxicity in shorter regimens. We evaluated hepatotoxicity in two novel regimens against the standard shorter regimen recommended by WHO. METHODS: Participants from the TB-TRUST and TB-TRUST plus trials were assigned to the WHO shorter regimen, a levofloxacin-based regimen, or a bedaquiline-based regimen. Liver function was tested bi-weekly in the first month, then monthly until treatment ended. Eligibility required receiving at least one drug dose and undergoing at least two liver function tests. RESULTS: Of 429 patients, hepatotoxicity was most prevalent in the WHO shorter group (26.7% of 169), compared to 4.7% in the levofloxacin group (172 patients), and 5.7% in the bedaquiline group (88 patients). The median peak ALT levels were 1.67 × ULN for WHO, 0.82 × ULN for levofloxacin, and 0.88 × ULN for bedaquiline groups. The incidence of drug-induced liver injury was significantly higher in the WHO group (18.3%) than in the levofloxacin (3.5%) and bedaquiline (4.6%) groups. Time to significant ALT elevation was about 2.8 months, with no differences between groups. CONCLUSIONS: Two novel regimens demonstrated lower hepatotoxicity compared to the WHO shorter regimen. Entire course management monitoring is recommended in RR-TB treatment.

Identification and quantitative analysis of genotoxic impurities in rifampicin: Development and validation of a targeted LC-MS/MS method for 1-amino-4-methylpiperazine.

Rifampicin, essential for long-term tuberculosis treatment, requires rigorous control of non-therapeutic impurities due to their potential adverse, including mutagenic effects. Reports on control strategies for genotoxic impurities in rifampicin have been limited. This study introduced an analytical method to identify potential genotoxic impurities from the synthesis of raw materials. The structure of the 25-deacetyl-23-acetyl-rifampicin genotoxic impurity was confirmed using nuclear magnetic resonance, high-resolution mass spectrometry (HRMS), and high-performance liquid chromatography (HPLC). An HPLC-HRMS method was established and validated for detecting another genotoxic impurity, 1-amino-4-methylpiperazine, adhering to the International Council on Harmonization guidelines, which include specificity, linearity, detection and quantification limits, accuracy, precision, and robustness. These developments improve the quality control strategy for genotoxic impurities in rifampicin, ensuring product safety.

Triple Infectious Syndrome: Pulmonary Tuberculosis and HIV in a Case of Pure Neuritic Leprosy With Underlying Diabetes Mellitus.

Pulmonary tuberculosis (PTB), human immunodeficiency virus (HIV), and leprosy are of public health importance, as all three diseases are communicable and contribute to disease burden in society. Co-infection with these three entities is extremely rare but leads to significant mortality and morbidity. We report a case that highlights the diagnostic challenges and therapeutic management of a patient who was diagnosed with pure neuritic leprosy on multibacillary-multidrug therapy (MB-MDT) and subsequently co-diagnosed with PTB and HIV. The patient was started on anti-tubercular therapy and anti-retroviral therapy for treatment under India's national health programs, which play a major role in treating those of low socioeconomic status. The optimization of these therapeutic drugs is quite challenging during treatment due to potential drug interactions and toxicities. High clinical suspicion is required to rule out PTB before initiating rifampicin-containing MB-MDT, which can lead to rifampicin-resistant TB and screening for HIV. As there is a social stigma associated with these patients, they require good psychological support during and after treatment.

Cryo-EM structures of a mycobacterial ABC transporter that mediates rifampicin resistance.

Drug-resistant Tuberculosis (TB) is a global public health problem. Resistance to rifampicin, the most effective drug for TB treatment, is a major growing concern. The etiological agent, Mycobacterium tuberculosis (Mtb), has a cluster of ATP-binding cassette (ABC) transporters which are responsible for drug resistance through active export. Here, we describe studies characterizing Mtb Rv1217c-1218c as an ABC transporter that can mediate mycobacterial resistance to rifampicin and have determined the cryo-electron microscopy structures of Rv1217c-1218c. The structures show Rv1217c-1218c has a type V exporter fold. In the absence of ATP, Rv1217c-1218c forms a periplasmic gate by two juxtaposed-membrane helices from each transmembrane domain (TMD), while the nucleotide-binding domains (NBDs) form a partially closed dimer which is held together by four salt-bridges. Adenylyl-imidodiphosphate (AMPPNP) binding induces a structural change where the NBDs become further closed to each other, which downstream translates to a closed conformation for the TMDs. AMPPNP binding results in the collapse of the outer leaflet cavity and the opening of the periplasmic gate, which was proposed to play a role in substrate export. The rifampicin-bound structure shows a hydrophobic and periplasm-facing cavity is involved in rifampicin binding. Phospholipid molecules are observed in all determined structures and form an integral part of the Rv1217c-1218c transporter system. Our results provide a structural basis for a mycobacterial ABC exporter that mediates rifampicin resistance, which can lead to different insights into combating rifampicin resistance.

Design of RNA Polymerase Inhibitors as Therapeutics for Tuberculous Meningitis.

BACKGROUND: Tuberculosis is an infectious disease caused by Mycobacterium tuber-culosis. The current treatment protocols for pulmonary tuberculosis are quite effective, even though the treatment requires 3-6 months. The current treatment protocols for extrapulmonary tuberculosis are based on the same drugs that are used for pulmonary tuberculosis. However, the success rates are much lower for certain types of extrapulmonary tuberculosis, such as tubercu-lous meningitis. Tuberculous meningitis is one of the very few diseases attributable to bacteria that have a very high short-term mortality rate among diagnosed patients, even after treatment with antibiotics that are effective for pulmonary tuberculosis. For example, rifampicin is highly effective for the treatment of pulmonary tuberculosis, but its effectiveness for the treatment of tuberculous meningitis is much lower. The reason for the lower effectiveness of rifampicin against tuberculous meningitis is that it has low Blood-Brain Barrier (BBB) permeability, which results in lower concentrations of the drug at the required sites in the central nervous system. METHODS: In this work, ligands having improved BBB permeability and pharmacokinetic and pharmacodynamic properties, either similar to or better than that of rifampicin, have been designed. The BBB permeability of the designed molecules was assessed by using pkCSM, a machine-learning model. Pharmacokinetic properties, drug-likeness, and synthesizability were assessed by using SWISS-MODEL. The binding affinity of the designed drugs was assessed by using AutoDock Vina. A customized scoring function, StWN score, was used for a quantitative weighted assessment of all the properties of interest to rank the designed molecules. RESULTS: In this study, drug-like ligands have been designed that have been predicted to have high BBB permeability as well as high affinity for RNA polymerase ß of Mycobacterium tuberculosis. CONCLUSION: The best ligands generated by the tools employed were selected as potential drugs to address the current need for better options for the treatment of tuberculous meningitis.

Antibiotic resistance challenge: evaluating anthraquinones as rifampicin monooxygenase inhibitors through integrated bioinformatics analysis.

OBJECTIVE: Antibiotic resistance poses a pressing and crucial global public health challenge, leading to significant clinical and health-related consequences. Substantial evidence highlights the pivotal involvement of rifampicin monooxygenase (RIFMO) in the context of antibiotic resistance. Hence, inhibiting RIFMO could offer potential in the treatment of various infections. Anthraquinones, a group of organic compounds, have shown promise in addressing tuberculosis. This study employed integrated bioinformatics approaches to evaluate the potential inhibitory effects of a selection of anthraquinones on RIFMO. The findings were subsequently compared with those of rifampicin (RIF), serving as a positive control inhibitor. METHODS: The AutoDock 4.0 tool assessed the binding free energy between 21 anthraquinones and the RIFMO catalytic cleft. The ligands were ranked based on the most favorable scores derived from ΔGbinding. The docking analyses for the highest-ranked anthraquinone and RIF underwent a cross-validation process. This validation procedure utilized the SwissDock server and the Schrödinger Maestro docking software. Molecular dynamics simulations were conducted to scrutinize the stability of the backbone atoms in free RIFMO, RIFMO-RIF, and RIFMO complexed with the top-ranked anthraquinone throughout a 100-ns computer simulation. The Discovery Studio Visualizer tool visualized interactions between RIFMO residues and ligands. An evaluation of the pharmacokinetics and toxicity profiles of the tested compounds was also conducted. RESULTS: Five anthraquinones were indicated with ΔGbinding scores less than - 10 kcal/mol. Hypericin emerged as the most potent RIFMO inhibitor, boasting a ΔGbinding score and inhibition constant value of - 12.11 kcal/mol and 798.99 pM, respectively. The agreement across AutoDock 4.0, SwissDock, and Schrödinger Maestro results highlighted hypericin's notable binding affinity to the RIFMO catalytic cleft. The RIFMO-hypericin complex achieved stability after a 70-ns computer simulation, exhibiting a root-mean-square deviation of 0.55 nm. Oral bioavailability analysis revealed that all anthraquinones except hypericin, sennidin A, and sennidin B may be suitable for oral administration. Furthermore, the carcinogenicity prediction analysis indicated a favorable safety profile for all examined anthraquinones. CONCLUSION: Inhibiting RIFMO, particularly with anthraquinones such as hypericin, holds promise as a potential therapeutic strategy for infectious diseases.

Optimization of Polylactide-Co-Glycolide-Rifampicin Nanoparticle Synthesis, In Vitro Study of Mucoadhesion and Drug Release.

Despite the large number of works on the synthesis of polylactide-co-glycolide (PLGA) nanoparticles (NP) loaded with antituberculosis drugs, the data on the influence of various factors on the final characteristics of the complexes are quite contradictory. In the present study, a comprehensive analysis of the effect of multiple factors, including the molecular weight of PLGA, on the size and stability of nanoparticles, as well as the loading efficiency and release of the antituberculosis drug rifampicin (RIF), was carried out. Emulsification was carried out using different surfactants (polyvinyl alcohol, Tween 80 and Pluronic F127), different aqueous-to-organic phase ratios, and different solvents (dichloromethane, dimethyl sulfoxide, ethyl acetate). In this research, the PLGA nanoemulsion formation process was accompanied by ultrasonic dispersion, at different frequencies and durations of homogenization. The use of the central composite design method made it possible to select optimal conditions for the preparation of PLGA-RIF NPs (particle size 223 ± 2 nm, loading efficiency 67 ± 1%, nanoparticles yield 47 ± 2%). The release of rifampicin from PLGA NPs was studied for the first time using the flow cell method and vertical diffusion method on Franz cells at different pH levels, simulating the gastrointestinal tract. For the purpose of the possible inhalation administration of rifampicin immobilized in PLGA NPs, their mucoadhesion to mucin was studied, and a high degree of adhesion of polymeric nanoparticles to the mucosa was shown (more than 40% within 4 h). In the example of strain H37Rv in vitro, the sensitivity of Mycobacterium tuberculosis to PLGA-RIF NPs was proven by the complete inhibition of their growth.

Implications of drug resistance in leprosy: disease course, reactions and the use of novel drugs.

Leprosy remains a significant neglected tropical disease despite the goal of elimination having been achieved in various endemic nations over the past two decades. Reactional episodes complicate the disease course, resulting in deformities and disability. The main aim of treatment is to kill Mycobacterium leprae and decrease the bacterial load, which could help prevent further bacilli transmission. A major concern in breaking the chain of transmission and possibly for recurrent reactions is the role of drug-resistant bacilli. Though some data is available on the background prevalence of drug resistance in leprosy, there is a paucity of studies that look for resistance specifically in leprosy reactions. Administration of long-term steroids or immunosuppressants for chronic and recurrent responses in the presence of drug resistance has the twin effect of perpetuating the multiplication of resistant bacilli and encouraging the dissemination of leprosy. The increasing trend of prescribing second-line drugs for leprosy or type 2 reactions without prior assessment of drug resistance can potentially precipitate a severe public health problem as this can promote the development of resistance to second-line drugs as well. A comprehensive multicenter study, including drug resistance surveillance testing in cases of reactions, is necessary, along with the current measures to stop the spread of leprosy. Here, we have detailed the history of drug resistance in leprosy, given pointers on when to suspect drug resistance, described the role of resistance in reactions, methods of resistance testing, and the management of resistant cases with second-line therapy.

[Evaluation of molecular diagnosis of tuberculosis and resistance to rifampicin with GeneXpert® MTB/RIF in Algeria]. / Évaluation du GeneXpert® MTB/RIF dans le diagnostic moléculaire de la tuberculose et de la résistance à la rifampicine en Algérie.

Objective: 1) To evaluate the contribution of the GeneXpert® MTB/RIF (GX) test in the diagnosis of pulmonary and extra-pulmonary tuberculosis compared to culture. 2) To compare the rifampicin results resistance obtained by GX with the phenotypic sensitivity test. Materials and methods: Retrospective study carried out over a period of five years, from May 2017 to June 2022 at the microbiology laboratory of the Central army Hospital Mohamed Seghir Nekkache, Algiers (Algeria). The pulmonary and extrapulmonary clinical specimens were collected, cultivated, tested by GX PCR and direct examination by Ziehl-Neelsen staining. The study of sensitivity to antituberculosis drugs was performed according to the proportion method on liquid medium Bactec MGIT 960 (or on solid medium Lowenstein-Jensen at the Algerian Pasteur Institute). Results: 310 samples were included in the final analysis of the study, of which 156 were of pulmonary origin and 154 of extrapulmonary origin. Mycobacterium tuberculosis complex (MTBC) was detected in 95 samples from 88 tuberculosis patients (sex ratio 2,03 and middle age 37 years) with 49 cases of pulmonary tuberculosis and 39 cases of extra-pulmonary tuberculosis. For 2 cases, the GX was positive while the culture was negative and for 11 cases, the GX was negative while the culture was positive. Thus, in our study and compared to culture, GX showed an overall sensitivity of 88.2%, a specificity of 98.6%, a positive predictive value (PPV) of 96.4% and a negative predictive value (NPV) of 95.2%. The analysis of the data according to the type of samples, the sensitivity, specificity, PPV and NPV of GX for the pulmonary and extrapulmonary samples were 96.3% vs. 77.0%, 98.0% vs. 99.1%, 96.2% vs. 96.5% and 98.0% vs. 92.7% respectively. The sensitivity of GX for disco-vertebral, lymph node, meningeal and pleural tuberculosis were 100%, 90.0%, 71.4% and 57.1% respectively. The sensitivity of GX for pulmonary tuberculosis compared to microscopy was 96% vs. 68%. The comparison of the results of detection of resistance to rifampicin by GX and by phenotypic methods showed perfect agreement. Discussion and conclusion: A good sensitivity of GX compared to microscopy was revealed. The GX is a useful tool for the diagnosis of pulmonary tuberculosis, especially in smear-negative cases. The sensitivity of GX in extrapulmonary tuberculosis varied depending on the location of the infection. A negative result by GX does not exclude tuberculosis and cases of resistance to RIF detected by GX must be confirmed by phenotypic method.

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.

A Case of Significant Coagulopathy Due to Vitamin K Deficiency Caused by the Administration of Cefazolin and Rifampicin and Hyponutrition After a Postoperative Infection of the Lumbar Spine.

Postoperative surgical site infection in the lumbar spine is one of the serious complications that sometimes results in death. Herein, we describe a case in which a patient was found to have coagulopathy due to vitamin K deficiency when he was transferred to a hospital for treatment for a postoperative infection of the lumbar spine. The coagulation disorder was caused by antimicrobial agents administered to the patient, who was suffering from hyponutrition. The patient was a 70-year-old man with a history of diabetes mellitus. He was diagnosed with lumbar spinal canal stenosis and underwent posterior decompression of the L2-L5 and S1 laminae at a previous hospital five months before transfer to our hospital. Four months before transfer, purulent discharge was observed from the wound, and methicillin-susceptible Staphylococcus aureus was detected in the wound culture. Cefazolin was administered for two weeks, resulting in initial improvement. However, one month before the transfer, the wound infection recurred, accompanied by bacteremia and a psoas abscess. He had been treated with cefazolin, levofloxacin, rifampicin, trimethoprim, and sulfamethoxazole, but the antibiotics' effects were insufficient. Upon transfer for debridement surgery due to uncontrolled infection, his coagulation parameters were as follows: prothrombin time (PT) 74.0 sec, PT-international normalized ratio (INR) 6.69, PT% 9.0, activated partial thromboplastin time (APTT) 138 sec, fibrinogen (FIB) 664 mg/dl, fibrin degradation products (FDP) 7.1 µg/ml, and protein induced by vitamin K absence-II (PIVKA-II) 34400 mAU/ml. Because we suspected vitamin K deficiency, vitamin K 40 mg was administered as a test dose, and coagulation function improved to PT 16.4 sec, PT-INR 1.30, PT% 65.2, and APTT 79 sec after four hours. The diagnosis of vitamin K deficiency was confirmed, vitamin K was administered for four days, and the coagulation status normalized five days after transfer. Debridement was performed for the left psoas abscess. Cefazolin was administered for eight weeks, and administration was completed. The coagulation abnormality did not recur due to careful attention to his nutrition. We experienced a case of coagulopathy due to vitamin K deficiency caused by antimicrobial agents administered to a hyponourished patient with a postoperative infection of the lumbar spine. The cause of vitamin K deficiency, in this case, was thought to be low nutrition, suppression of vitamin K-producing bacteria by cefazolin and rifampicin, and the use of cefazolin with a methyl-thiadiazole thiol group. It should be kept in mind that severe coagulopathy due to vitamin K deficiency caused by antimicrobial treatment with hyponutrition can occur in postoperative infections.

Identification of gene targets that potentiate the action of rifampicin on Mycobacterium bovis BCG.

Tuberculosis (TB) caused by bacteria of the Mycobacterium tuberculosis complex remains one of the most important infectious diseases of mankind. Rifampicin is a first line drug used in multi-drug treatment of TB, however, the necessary duration of treatment with these drugs is long and development of resistance is an increasing impediment to treatment programmes. As a result, there is a requirement for research and development of new TB drugs, which can form the basis of new drug combinations, either due to their own anti-mycobacterial activity or by augmenting the activity of existing drugs such as rifampicin. This study describes a TnSeq analysis to identify mutants with enhanced sensitivity to sub-minimum inhibitory concentrations (MIC) of rifampicin. The rifampicin-sensitive mutants were disrupted in genes of a variety of functions and the majority fitted into three thematic groups: firstly, genes that were involved in DNA/RNA metabolism, secondly, genes involved in sensing and regulating mycobacterial cellular systems, and thirdly, genes involved in the synthesis and maintenance of the cell wall. Selection at two concentrations of rifampicin (1/250 and 1/62 MIC) demonstrated a dose response for mutants with statistically significant sensitivity to rifampicin. The dataset reveals mechanisms of how mycobacteria are innately tolerant to and initiate an adaptive response to rifampicin; providing putative targets for the development of adjunctive therapies that potentiate the action of rifampicin.