Short course chemotherapy for tuberculous lymphadenitis in children.

OBJECTIVE--To assess the efficacy of a short course chemotherapy regimen for treating tuberculosis of the lymph nodes in children. DESIGN--Open, collaborative, outpatient clinical trial. SETTING--Outpatient department of the Tuberculosis Research Centre, paediatric surgery departments of the Institute of Child Health and Hospital for Children and the Government Stanley Hospital, Madras, South India. PATIENTS--Children aged 1-12 years with extensive, multiple site, superficial tuberculous lymphadenitis confirmed by biopsy (histopathology or culture). INTERVENTIONS--Patients were treated with a fully supervised intermittent chemotherapy regimen consisting of streptomycin, rifampicin, isoniazid, and pyrazinamide three times a week for two months followed by streptomycin and isoniazid twice a week for four months on an outpatient basis. Surgery was limited to biopsy of nodes for diagnosis and assessment. MAIN OUTCOME MEASURES--Response to chemotherapy was assessed by regression of lymph nodes and healing of sinuses and abscesses during treatment and follow up. Compliance with treatment and frequency of adverse reactions were also estimated. RESULTS--197 Patients were admitted to the study and 168 into the analysis. The regimen was well tolerated and compliance was good with 101 (60%) patients receiving the prescribed chemotherapy within 15 days of the stipulated period of six months. Those whose chemotherapy extended beyond that period received the same total number of doses. Clinical response was favourable in most patients at the end of treatment. Sinuses and abscesses healed rapidly. Residual lymphadenopathy (exceeding 10 mm diameter) was present in 50 (30%) patients at the end of treatment; these nodes were biopsied. Fresh nodes, increase in size of nodes, and sinuses and abscesses occurred both during treatment and follow up. After 36 months of follow up after treatment only 5 (3%) patients required retreatment for tuberculosis. CONCLUSION--Tuberculous lymphadenitis in children can be successfully treated with a short course chemotherapy regimen of six months.     

A novel solid dosage form of rifampicin and isoniazid with improved functionality

The aim of the present investigation was to develop a novel dosage form of rifampicin and isoniazid to minimize degradation of rifampicin in acidic medium and to modulate the release of rifampicin in the stomach and isoniazid in the intestine. Gastroretentive tablets of rifampicin (150 mg) were prepared by the wet granulation method using hydroxypropyl methylcellulose, calcium carbonate, and polyethylene glycol 4000. The granules and tablets of rifampicin were characterized. Hard gelatin capsules (size 4) containing a compacted mass of isoniazid (150 mg) and dicalcium phosphate (75 mg) were enteric coated. Two tablets of rifampicin and 1 capsule (size 4) of isoniazid were put into a hard gelatin capsule (size 00). The in vitro drug release and in vitro drug degradation studies were performed. Rifampicin was released over 4 hours by zero-order kinetics from the novel dosage form. More than 90% of isoniazid was released in alkaline medium in 30 minutes. The results of dissolution studies with the US Pharmacopeia XXIII method revealed that a substantial amount of rifampicin was degraded from the immediate release capsule containing rifampicin and isoniazid powder owing to drug accumulation in the dissolution vessel and also to the presence of isoniazid. The degradation of rifampicin to 3-formyl rifampicin SV (3FRSV) was arrested (3.6%–4.8% degradation of rifampicin at 4 hours) because of the minimization of physical contact between the 2 drugs and controlled release of rifampicin in acidic medium in the modified Rossett-Rice apparatus. This study concludes that the problem of rifampicin degradation can be alleviated to a certain extent by this novel dosage form. Published: August 24, 2007     

Intermittent Chemotherapy for Tuberculosis in an Urban Community

A regimen designed for effective foolproof antituberculosis treatment, acceptable on a routine basis, was applied to all patients newly diagnosed at the Chest Clinic, Hammersmith Hospital, in 1963, 1964, and 1965. During the first three months of treatment patients received daily (six days a week) streptomycin 0.75 g. plus isoniazid 300 mg. plus sodium para-aminosalicylate (P.A.S.) 12 g. The P.A.S. was usually stopped when bacterial sensitivity reports made this possible. For a further 15 months streptomycin 1 g. plus isoniazid 600 mg. was given on three alternate days each week to complete a total of 18 months'' treatment.Of the total of 140 patients (66% sputum-positive) 112 (80%) completed the planned 18 months with intermittent streptomycin plus isoniazid and a further eight completed treatment on alternative regimens (a total of 85%). The equivalent figures for one year are 88% and 94%. Excellent clinical and radiological results, together with sputum conversion, were achieved in 138 of the 140 patients (99%). Only two patients were lost from surveillance, because of failure to co-operate, before quiescence was obtained.It is concluded that the total efficiency of supervised intermittent treatment is greater than that of unsupervised daily regimens. Since 100% arrest of tuberculosis is possible with co-operative patients, less should not be accepted in developed countries.     

Randomized Clinical Trial of Thrice-Weekly 4-Month Moxifloxacin or Gatifloxacin Containing Regimens in the Treatment of New Sputum Positive Pulmonary Tuberculosis Patients

Background

Shortening tuberculosis (TB) treatment duration is a research priority. This paper presents data from a prematurely terminated randomized clinical trial, of 4-month moxifloxacin or gatifloxacin regimens, in South India.

Methods

Newly diagnosed, sputum-positive HIV-negative pulmonary TB patients were randomly allocated to receive gatifloxacin or moxifloxacin, along with isoniazid and rifampicin for 4 months with pyrazinamide for first 2 months (G or M) or isoniazid and rifampicin for 6 months with ethambutol and pyrazinamide for first 2 months (C). All regimens were administered thrice-weekly. Clinical and bacteriological assessments were done monthly during treatment and for 24 months post-treatment. The Data and Safety Monitoring Board recommended termination of the trial due to high TB recurrence rates in the G and M regimens.

Results

Of 416 patients in intent-to-treat analysis, 6 (5%) of 124, 2 (2%) of 110 and 2 (2%) of 137 patients with drug-susceptible TB in the G, M and C arms respectively had unfavorable response at the end of treatment; during the next 24 months, 17 (15%) of 115, 11 (11%) of 104 and 8 (6%) of 132 patients respectively, had TB recurrence. Of 38 drug-resistant patients 1 of 8 and 3 of 26 in the G and C arms respectively had unfavourable response at the end of treatment; and TB recurrence occurred in 2 of 7 and 2 of 23 patients, respectively. The differences in TB recurrence rates between the G and C arms was statistically significant (p = 0.02). Gastro-intestinal symptoms occurred in 23%, 22% and 9% of patients in the G, M and C arms respectively, but most reactions were mild and manageable with symptomatic measures; 1% required regimen modification.

Conclusions

4-month thrice-weekly regimens of gatifloxacin or moxifloxacin with isoniazid, rifampicin and pyrazinamide, were inferior to standard 6-month treatment, in patients with newly diagnosed sputum positive pulmonary TB.

Trial Registration

Clinical Trials Registry of India CTRI/2012/10/003060     

Effect of Rifampicin and Isoniazid on Liver Function

The effects of rifampicin and isoniazid on liver function have been studied in 63 patients with pulmonary tuberculosis; 29% showed abnormalities of serum aspartate aminotransferase (SGOT) and a similar percentage abnormalities of serum bilirubin. These usually occurred during the first 12 weeks of therapy. The average duration of the abnormalities was 14½ days, irrespective of whether treatment was interrupted or not.The relationship between raised SGOT and acetylator phenotype in a small number of patients suggests that those with raised SGOT are usually slow acetylator phenotypes. It seems that hepatic reactions in patients with previously normal liver function are usually mild and non-specific. However, patients who continue with rifampicin should be kept under close biochemical observation.     

Prevalence,Risk Factors,and Treatment Outcomes of Isoniazid- and Rifampicin- Mono-Resistant Pulmonary Tuberculosis in Lima,Peru

BackgroundIsoniazid and rifampicin are the two most efficacious first-line agents for tuberculosis (TB) treatment. We assessed the prevalence of isoniazid and rifampicin mono-resistance, associated risk factors, and the association of mono-resistance on treatment outcomes.MethodsA prospective, observational cohort study enrolled adults with a first episode of smear-positive pulmonary TB from 34 health facilities in a northern district of Lima, Peru, from March 2010 through December 2011. Participants were interviewed and a sputum sample was cultured on Löwenstein-Jensen (LJ) media. Drug susceptibility testing was performed using the proportion method. Medication regimens were documented for each patient. Our primary outcomes were treatment outcome at the end of treatment. The secondary outcome included recurrent episodes among cured patients within two years after completion of the treatment.ResultsOf 1292 patients enrolled, 1039 (80%) were culture-positive. From this subpopulation, isoniazid mono-resistance was present in 85 (8%) patients and rifampicin mono-resistance was present in 24 (2%) patients. In the multivariate logistic regression model, isoniazid mono-resistance was associated with illicit drug use (adjusted odds ratio (aOR) = 2.10; 95% confidence interval (CI): 1.1–4.1), and rifampicin mono-resistance was associated with HIV infection (aOR = 9.43; 95%CI: 1.9–47.8). Isoniazid mono-resistant patients had a higher risk of poor treatment outcomes including treatment failure (2/85, 2%, p-value<0.01) and death (4/85, 5%, p<0.02). Rifampicin mono-resistant patients had a higher risk of death (2/24, 8%, p<0.01).ConclusionA high prevalence of isoniazid and rifampicin mono-resistance was found among TB patients in our low HIV burden setting which were similar to regions with high HIV burden. Patients with isoniazid and rifampicin mono-resistance had an increased risk of poor treatment outcomes.     

Sensitivity to Rifampicin: Incidence,Mechanism, and Prevention

Five out of 200 patients taking rifampicin 900 mg twice weekly and three out of 91 patients taking rifampicin who attended an immunology clinic developed intolerance to the drug. Antibodies to rifampicin, which were found in most cases, decreased steadily after the end of treatment but were detectable for up to 16 months. The dose of rifampicin and the blood levels are predominating factors in the occurrence of reactions. Thus the dose should be reduced in patients in whom rifampicin blood levels rise abnormally. When it is important to continue rifampicin treatment despite intolerance antibody titres within 24 hours after administration of the drug must be measured to find when they are lowest, which determines the “unreactive period,” and when a further dose may be safely given.     

High Isoniazid Resistance Rates in Rifampicin Susceptible Mycobacterium tuberculosis Pulmonary Isolates from Pakistan

Background

Rapid new diagnostic methods (including Xpert MTB/RIF assay) use rifampicin resistance as a surrogate marker for multidrug resistant tuberculosis. Patients infected with rifampicin susceptible strains are prescribed first line anti-tuberculosis therapy. The roll out of such methods raises a concern that strains with resistance to other first line anti-tuberculosis drugs including isoniazid will be missed and inappropriate treatment given. To evaluate implications of using such methods review of resistance data from high burden settings such as ours is essential.

Objective

To determine resistance to first line anti-tuberculosis drugs amongst rifampicin susceptible pulmonary Mycobacterium tuberculosis (MTB) isolates from Pakistan.

Materials and Methods

Data of pulmonary Mycobacterium tuberculosis strains isolated in Aga Khan University Hospital (AKUH) laboratory (2009–2011) was retrospectively analyzed. Antimicrobial susceptibility profile of rifampicin susceptible isolates was evaluated for resistance to isoniazid, pyrazinamide, ethambutol, and streptomycin.

Results

Pulmonary specimens submitted to AKUH from 2009 to 2011 yielded 7738 strains of Mycobacterium tuberculosis. These included 54% (n 4183) rifampicin susceptible and 46% (n: 3555) rifampicin resistant strains. Analysis of rifampicin susceptible strains showed resistance to at least one of the first line drugs in 27% (n:1133) of isolates. Overall isoniazid resistance was 15.5% (n: 649), with an isoniazid mono-resistance rate of 4% (n: 174). Combined resistance to isoniazid, pyrazinamide, and ethambutol was noted in 1% (n: 40), while resistance to isoniazid, pyrazinamide, ethambutol, and streptomycin was observed in 1.7% (n: 70) of strains.

Conclusions

Our data suggests that techniques (including Xpert MTB/RIF assay) relying on rifampicin susceptibility as an indicator for initiating first line therapy will not detect patients infected with MTB strains resistant to other first line drugs (including isoniazid). The roll out of these techniques must therefore be accompanied by strict monitoring ensuring early resistance detection to increase chances of improved patient outcomes.     

Pharmacokinetics of isoniazid and rifampicin in an experiment and in clinical practice

Efficacy of drugs in patients with pulmonary tuberculosis mostly depends on their concentration in organs and tissues. To show distribution profiles of antituberculous drugs in patients in organs and tissues of experimental animals after their administration alone or in combination, pharmacokinetic parameters of isoniazid and rifampicin were studied. The drug concentrations, half-lives and distribution volumes were determined in 50 patients and 60 experimental animals. It was observed that after combined use of isoniazid and rifampicin their concentrations in the lung tissue and liver of the experimental animals increased which led to increasing their half-lives in patients.     

Comparative analysis of TB-Biochip, Xpert MTB/RIF, and GenoType MTBDRplus test systems for rapid determination of mutations responsible for drug resistance of M. tuberculosis complex (in sputum from patients in Moscow region)

We studied the frequency of occurrence and combinations of mutations in rpoB, katG, inhA, and oxyR-ahpC genes of Mycobacterium tuberculosis (MTB) DNA isolated from patients of Moscow region. In isoniazid monoresistant MTB isolates, Ser315Thr mutation in the katG gene prevails (15.8%), whereas the most frequent mutations in multidrug-resistant MTB isolates were Ser531Leu in the rpoB gene, Ser315Thr in the katG gene (26.3%), and their combination with C(-15)T in the inhA gene (5.3%). The efficiency of TB-Biochip (OOO Biochip-IMB Russia), Xpert MTB/RIF (Cepheid, United States), and GenoType MTBDRplus (Hain Lifescience, Germany) test systems was analyzed and compared with the efficiency of luminescent microscopy and phenotypic drug-susceptibility testing in BACTEC? MGIT? 960 automated system (Becton, Dickinson and Company, United States). Using Xpert MTB/RIF, TB-Biochip, and GenoType MTBDRplus systems, MTB DNA was detected in sputum from patients in 92, 78, and 49% of all culturepositive cases, respectively. Standard cultural data match the test results of the susceptibility of MTB for Xpert MTB/RIF (rifampicin resistance) and for TB-Biochip and GenoType MTBDRplus (resistance to rifampicin and isoniazid) by 100, 97, and 100%, respectively. Thus, Xpert MTB/RIF system is the most efficient in primary MTB DNA detection, and TB-Biochip is the only one sensitive enough for both MTB DNA detection and determination of MTB multidrug resistance in sputum. Multidrug resistance is considered as resistance to both rifampicin and isoniazid.     

Bacteriological conversion in twenty urinary tuberculosis patients treated with ofloxacin, rifampin and isoniazid: a 10-year follow-up study

Twenty patients with urinary tuberculosis were treated with ofloxacin (200 mg/day, 6 months), rifampin (600 mg/day, 3 months) and isoniazid (300 mg/day, 3 months) between 1989 and 1990. All patients were new cases, diagnosed by observation and/or isolation of Mycobacterium tuberculosis in one of the three morning urine samples. Bacteriological culture conversion (negativization) was assessed as a clinical guide of efficacy, comparing it, as the only parameter, against a control group (150 patients) with urinary tuberculosis who received conventional therapy. Bacteriological follow-up studies were performed in both groups monthly for 6 months, then again 6 months later and then every year for 10 years after completion of treatment. In the 20 patients, the initial culture was positive with over 100 colonies per culture (>50%); the smear was positive in 45% of the patients (most were 2+). All strains were susceptible to rifampin, isoniazid and ofloxacin. Two patients discontinued treatment. Beginning with the first month of treatment, the bacteriological conversion was 100%, 89.5% and 100% in the remaining controls. In the control group, which received conventional treatment, the conversion was: 90%, 87%, 93% and 100% in the remaining controls. Treatment with ofloxacin resulted in a bacteriological conversion similar to that following conventional treatment (p>0.05, Fisher's exact test). After 10 years of patient follow-up, we conclude that ofloxacin, in combination with rifampin and isoniazid (both for 3 months only is effective against M. tuberculosis, providing satisfactory bacteriological and clinical efficacy. Electronic Publication     

Pharmacokinetics of Isoniazid,Pyrazinamide, and Ethambutol in Newly Diagnosed Pulmonary TB Patients in Tanzania

Exposure to lower-than-therapeutic levels of anti-tuberculosis drugs is likely to cause selection of resistant strains of Mycobacterium tuberculosis and treatment failure. The first-line anti-tuberculosis (TB) regimen consists of rifampicin, isoniazid, pyrazinamide, and ethambutol, and correct management reduces risk of TB relapse and development of drug resistance. In this study we aimed to investigate the effect of standard of care plus nutritional supplementation versus standard care on the pharmacokinetics of isoniazid, pyrazinamide and ethambutol among sputum smear positive TB patients with and without HIV. In a clinical trial in 100 Tanzanian TB patients, with or without HIV infection, drug concentrations were determined at 1 week and 2 months post initiation of anti-TB medication. Data was analysed using population pharmacokinetic modelling. The effect of body size was described using allometric scaling, and the effects of nutritional supplementation, HIV, age, sex, CD4+ count, weight-adjusted dose, NAT2 genotype, and time on TB treatment were investigated. The kinetics of all drugs was well characterised using first-order elimination and transit compartment absorption, with isoniazid and ethambutol described by two-compartment disposition models, and pyrazinamide by a one-compartment model. Patients with a slow NAT2 genotype had higher isoniazid exposure and a lower estimate of oral clearance (15.5 L/h) than rapid/intermediate NAT2 genotype (26.1 L/h). Pyrazinamide clearance had an estimated typical value of 3.32 L/h, and it was found to increase with time on treatment, with a 16.3% increase after the first 2 months of anti-TB treatment. The typical clearance of ethambutol was estimated to be 40.7 L/h, and was found to decrease with age, at a rate of 1.41% per year. Neither HIV status nor nutritional supplementations were found to affect the pharmacokinetics of these drugs in our cohort of patients.     

Molecular genotyping of Mycobacterium tuberculosis strains isolated from patients in the Samara region by the restriction DNA fragment length polymorphism

The typing of 106 M. tuberculosis (MBT) strains isolated from patients in the Samara region by the restriction DNA fragment length polymorphism (RFLP) IS6110 revealed that most of the strains (71.7%) belonged to the W family, 5 MBT strains (4.7%) belonged to the AI family, one culture was the mixture of two strains, AI and W. In addition, 24 MBT strains (22.6%) classified with other genotypes were detected. The analysis of the sensitivity of the MBT strains to rifampicin and isoniazid, with the method of absolute concentrations and by point mutations, demonstrated that 29 MBT strains (27.3%) were sensitive to rifampicin and isoniazid and 56 MBT strains (52.9%) were resistant to rifampicin and isoniazid simultaneously. Among the MBT strains of different RFLP families, strains both sensitive and resistant to these two preparations could be detected, but strains with multiple drug resistance prevailed in the W family (61.8%).     

The Impact of Isoniazid Resistance on the Treatment Outcomes of Smear Positive Re-Treatment Tuberculosis Patients in the State of Andhra Pradesh,India

Background

Multi drug resistant and rifampicin resistant TB patients in India are treated with the World Health Organization (WHO) recommended standardized treatment regimens but no guidelines are available for the management of isoniazid (INH) resistant TB patients. There have been concerns that the standard eight-month retreatment regimen being used in India (2H₃R₃Z₃E₃S₃/1H₃R₃Z₃E₃/5H₃R₃E₃; H-Isoniazid; R-Rifampicin; Z-Pyrazinamide; E-Ethambutol; S-Streptomycin) may be inadequate to treat INH resistant TB cases and leads to poor treatment outcomes. We aimed to assess if INH resistance is associated with unfavorable treatment outcomes (death, default, failure and transferred out) among a cohort of smear positive retreatment TB patients registered in three districts of Andhra Pradesh, India.

Methods

We conducted a retrospective record review of all smear positive retreatment TB patients without rifampicin resistance registered during April–December 2011.

Results

Of 1,947 TB patients, 1,127 (58%) were tested with LPA—50 (4%) were rifampicin resistant, 933 (84%) were sensitive to INH and rifampicin and 144 (12%) were INH resistant. Of 144 INH resistant cases, 64 (44%) had poor treatment outcomes (25 (17%) default, 22 (15%) death, 12 (8%) failure and 5 (3%) transfer out) as compared to 287 (31%) among INH sensitive cases [aRR 1.46; 95%CI (1.19–1.78)].

Conclusion

Our study confirms that INH resistance is independently associated with unfavorable treatment outcomes among smear positive retreatment TB patients, indicating that the current treatment regimen may be inadequate. These findings call for an urgent need for randomized controlled trials to discover the most effective treatment regimen for managing INH resistant TB.     

Detection of mutations associated with multidrug-resistant Mycobacterium tuberculosis clinical isolates

Antimicrobial resistance was studied in 100 Mycobacterium tuberculosis strains selected randomly from sputum cultures of newly diagnosed tuberculosis patients. Resistance of the isolates to rifampicin, isoniazid, and ethambutol was tested by both drug susceptibility testing (DST) and allele-specific PCR (AS-PCR). A total of 19 (19%) isolates were found resistant to at least one of the antituberculosis drugs investigated by PCR compared with 14 (14%) resistant isolates detected by DST. Eleven mutations were detected by AS-PCR in the rpoB gene (codons 516, 526, and 531), associated with rifampicin resistance, a marker of multidrug-resistant tuberculosis (MDR-TB), 14 mutations in the katG gene codon 315 that confers resistance to isoniazid, and nine mutations in the embB gene codon 306 that confers resistance to ethambutol. Mutations in the six multidrug-resistant isolates were confirmed by DNA sequencing. Results were compared with phenotypic DST data. Nineteen different mutation types to at least one of the drugs were found; six isolates (6%) were classified as MDR-TB, defined as resistance to at least rifampicin and isoniazid. The rates of concordance of the PCR with the phenotypic susceptibility test were 71.4, 54.5, and 44.4 for isoniazid, rifampicin, and ethambutol, respectively. These results highlight the importance of molecular epidemiology studies of tuberculosis in understudied regions with a tuberculosis burden to uncover the true prevalence of the MDR-TB.     

New approaches in the diagnosis and treatment of latent tuberculosis infection

With nearly 9 million new active disease cases and 2 million deaths occurring worldwide every year, tuberculosis continues to remain a major public health problem. Exposure to Mycobacterium tuberculosis leads to active disease in only ~10% people. An effective immune response in remaining individuals stops M. tuberculosis multiplication. However, the pathogen is completely eradicated in ~10% people while others only succeed in containment of infection as some bacilli escape killing and remain in non-replicating (dormant) state (latent tuberculosis infection) in old lesions. The dormant bacilli can resuscitate and cause active disease if a disruption of immune response occurs. Nearly one-third of world population is latently infected with M. tuberculosis and 5%-10% of infected individuals will develop active disease during their life time. However, the risk of developing active disease is greatly increased (5%-15% every year and ~50% over lifetime) by human immunodeficiency virus-coinfection. While active transmission is a significant contributor of active disease cases in high tuberculosis burden countries, most active disease cases in low tuberculosis incidence countries arise from this pool of latently infected individuals. A positive tuberculin skin test or a more recent and specific interferon-gamma release assay in a person without overt signs of active disease indicates latent tuberculosis infection. Two commercial interferon-gamma release assays, QFT-G-IT and T-SPOT.TB have been developed. The standard treatment for latent tuberculosis infection is daily therapy with isoniazid for nine months. Other options include therapy with rifampicin for 4 months or isoniazid + rifampicin for 3 months or rifampicin + pyrazinamide for 2 months or isoniazid + rifapentine for 3 months. Identification of latently infected individuals and their treatment has lowered tuberculosis incidence in rich, advanced countries. Similar approaches also hold great promise for other countries with low-intermediate rates of tuberculosis incidence.     

Controlled Comparison of Oral Twice-weekly and Oral Daily Isoniazid plus PAS in Newly Diagnosed Pulmonary Tuberculosis

A controlled clinical trial was undertaken in 247 patients with newly diagnosed pulmonary tuberculosis to assess the relative efficacies of a fully supervised twice-weekly oral regimen of isoniazid plus PAS (para-aminosalicylic acid) and a standard self-administered daily regimen of the same drugs following an initial intensive phase of two weeks of daily streptomycin, PAS, and isoniazid. Among patients who had isoniazid-sensitive cultures initially and who attended the clinic regularly the numbers with a favourable bacteriological response at the end of the year of chemotherapy were 79 (88%) out of 90 for the twice-weekly regimen and 72 (87%) out of 83 for the daily regimen; the numbers of patients with considerable radiographic improvement were 54 (60%) and 53 (64%) respectively. Complaints of vomiting or diarrhoea that did not require a reduction of the PAS dosage were made on one or two occasions by 23(21%) out of 109 twice-weekly and 25 (23%) out of 108 daily patients, and on at least three occasions by 4 (4%) and 12 (11%) respectively. Finally, all five patients who had chemotherapy changed on account of hypersensitivity to PAS had been receiving the daily regimen, as also had one patient who died of agranulocytosis.     

Reduction of elevated plasma globotriaosylsphingosine in patients with classic Fabry disease following enzyme replacement therapy

Fabry disease is treated by two-weekly infusions with α-galactosidase A, which is deficient in this X-linked globotriaosylceramide (Gb3) storage disorder. Elevated plasma globotriaosylsphingosine (lysoGb3) is a hallmark of classical Fabry disease. We investigated effects of enzyme replacement therapy (ERT) on plasma levels of lysoGb3 and Gb3 in patients with classical Fabry disease treated with agalsidase alfa at 0.2 mg/kg, agalsidase beta at 0.2 mg/kg or at 1.0 mg/kg bodyweight. Each treatment regimen led to prominent reductions of plasma lysoGb3 in Fabry males within 3 months (P = 0.0313), followed by relative stability later on. Many males developed antibodies against α-galactosidase A, particularly those treated with agalsidase beta. Patients with antibodies tended towards smaller correction in plasma lysoGb3 concentration, whereas treatment with high dose agalsidase beta allowed a reduction comparable to patients without antibodies. Pre-treatment plasma lysoGb3 concentrations of Fabry females were relatively low. In all females and with each treatment regimen, ERT gave reduction or stabilisation of plasma lysoGb3. Our investigation revealed that ERT of Fabry patients reduces plasma lysoGb3, regardless of the recombinant enzyme used. This finding shows that ERT can correct a characteristic biochemical abnormality in Fabry patients.     

Utility of nitrate reductase assay for detection of multidrug-resistant Mycobacterium tuberculosis in a low resource setting

Introduction. The performance of a drug susceptibility test may change when moving from the research stage to implementation on a population level in actual public health practice. Objective. The performance of a rapid drug susceptibility test was described for detecting multidrug-resistant Mycobacterium tuberculosis when implemented in the routine workflow of a low-resource reference laboratory. Materials and methods. A prospective study was done comparing the performance of the nitrate reductase assay with the conventional proportion method for rifampicin and isoniazid on 364 isolates were obtained from multidrug-resistant tuberculosis risk patients referred from diffrent Colombian laboratories. Results. When compared with the proportion method, the nitrate reductase assay sensitivity was 86.8% and 84.9% for rifampicin and isoniazid, respectively, whereas nitrate reductase assay specificity was 100% for isoniazid and rifampicin. Nitrate reductase assay sensitivity was significantly higher when the age of isolate was less than 70 days. A sensitivity of 94.4% dropped to 78.1% for rifampicin resistance for fresh and old isolates, respectively (Fisher exact test, p=0.05). For isoniazid resistance using fresh and old isolates, 94.7% vs.74.3% sensitivities, were achieved (chi square test, p=0.03). The proportion of nitrate reductase assay ambiguous results was significantly higher in multidrug-resistant than in non-multidrug-resistant isolates (17.6% vs. 4.0%, chi square test, p<0.005). Conclusions. The nitrate reductase assay demonstrated provided reliable results for antibiotic resistance. However, using old cultures leds to a higher proportion of false sensitive results; furthermore, the nitrate reductase assay capability to detect multidrug-resistant tuberculosis decreased due to a higher proportion of non-interpretable results.     

The Antipsychotic Thioridazine Shows Promising Therapeutic Activity in a Mouse Model of Multidrug-Resistant Tuberculosis

Multidrug- and extensively drug-resistant tuberculosis have emerged as grave threats to public health worldwide. Very few active drugs are available or likely to become available soon. To address these problems we revisited a classical observation, the applicability of phenothiazines as antimicrobial drugs. Within this pharmacological class we selected thioridazine, which is most efficacious and least toxic, when used as an antipsychotic drug. We tested thioridazine monotherapy in the Balb/c mouse model for its activity to treat both susceptible and multidrug-resistant tuberculosis by a two months daily oral administration of 32 and 70 mg/kg. In addition, we tested its additive value when combined with a standard first-line regimen for susceptible tuberculosis. Thioridazine treatment resulted in a significant reduction of colony-forming-units of the susceptible (−4.4 log CFU, p<0.05) and multidrug-resistant tuberculosis bacilli (−2.4 log CFU, p<0.009) in the lung both at one and two months after infection, compared to controls. Moreover, when thioridazine was added to a regimen containing rifampicin, isoniazid and pyrazinamide for susceptible tuberculosis, a significant synergistic effect was achieved (−6.2 vs −5.9 log CFU, p<0.01). Thioridazine may represent an effective compound for treatment of susceptible and multidrug-resistant tuberculosis. The phenothiazines and their targets represent interesting novel opportunities in the search for antituberculosis drugs.