The effectiveness of a 9-month regimen of isoniazid alone versus 3- and 4-month regimens of isoniazid plus rifampin for treatment of latent tuberculosis infection in children: results of an 11-year randomized study

Poor Compliance Makes Treatment of Latent Tuberculosis Infection Unsatisfactory

Objectives: The recommended treatment for latent tuberculosis infection is isoniazid for 9 months, but this regimen has a low completion rate. The authors wanted to compare treatment with isoniazid and treatment with isoniazid and rifampin in the typical public health setting in a large diverse state and recover as much information as possible from a state database. Methods: Patients who received latent tuberculosis infection treatment were identified in the Texas Department of State Health Services database for the years 1995-2002. Treatment completion, adverse reactions, and disease development were recorded. Results were analyzed using logistic regression to predict disease development. Results: In sum, 50 578 patients received isoniazid, and 280 received isoniazid/rifampin. Sixty-one percent of the isoniazid group and 54% of the isoniazid/rifampin group completed treatment. Eighteen percent of the isoniazid/rifampin group possibly had adverse reactions and discontinued treatment; 3% of the isoniazid group discontinued therapy because of side effects. More than 70% of patients with adverse reactions in the isoniazid/rifampin group took the treatment for more than 4 months. Overall, 168 patients in the isoniazid group with a normal chest X-ray and a positive skin test developed tuberculosis during follow-up to 2008; no patients in the isoniazid/rifampin group who had a normal X-ray and completed chemoprophylaxis developed tuberculosis during follow-up. Conclusions: The isoniazid/rifampin regimen appears to be as effective as the isoniazid regimen. However, completion rates on combination therapy were slightly lower. This regimen needs more formal clinical study since it has the potential to decrease administrative costs and improve completion rates. In addition, state departments of health need to develop networks using community-based resources to reach patients and increase completion rates.

Challenges and opportunities in developing novel drugs for TB

Mycobacterium tuberculosis is a difficult pathogen to combat and the first-line drugs currently in use are 40-60 years old. The need for new TB drugs is urgent, but the time to identify, develop and ultimately advance new drug regimens onto the market has been excruciatingly slow. On the other hand, the drugs currently in clinical development, and the recent gains in knowledge of the pathogen and the disease itself give us hope for finding new drug targets and new drug leads. In this article we highlight the unique biology of the pathogen and several possible ways to identify new TB chemical leads. The Global Alliance for TB Drug Development (TB Alliance) is a not-for-profit organization whose mission is to accelerate the discovery and development of new TB drugs. The organization carries out research and development in collaboration with many academic laboratories and pharmaceutical companies around the world. In this perspective we will focus on the early discovery phases of drug development and try to provide snapshots of both the current status and future prospects.

Latent tuberculosis: concordance and duration of treatment regimens

Over the past century, the UK has made significant progress in combating tuberculosis (TB) through improved health care and better preventative measures. However, it has now been identified as a new threat that needs concerted action. An important component in dealing with this threat is identifying and treating people with latent infection. This will prevent active disease and thwart the spread of tuberculosis infection. The aim of the study was to determine whether treatment concordance was affected by length of treatment regimen in the UK and to identify factors that may impact upon treatment completion. The audit was spread over a two-year period and looked at all patients on treatment for latent infection using the UK recommended regimens of either three months of dual therapy or six months using monotherapy. The results indicated that the 3-month regime had not improved concordance, as expected, with a slightly better completion rate in the 6-month group. However, the study did highlight a 'lost-to-follow-up' group of patients, who failed to present themselves following presumed completion.

Rifampicin-isoniazid induced fatal fulminant hepatitis during treatment of latent tuberculosis: A case report and literature review

A 42-year-old Indian man received 450 mg rifampicin (RIF) and 150 mg isoniazid (INH) daily after being diagnosed of a latent tuberculosis infection. Baseline serum aminotransferase and total bilirubin levels were within normal limits. On day 31 of treatment, the patient experienced epigastric discomfort and general malaise and one week later he developed nausea and episodic vomiting. The patient missed his first scheduled clinic appointment and he continued taking RIF-INH despite his symptoms. He visited the tuberculosis clinic on day 47 of treatment where he was found to be jaundiced and his liver enzymes were elevated. RIF-INH was stopped and the patient was admitted to our hospital as a case of RIF-INH induced hepatitis. On the 7th day of hospitalization, the patient developed consciousness disturbance with flapping tremor and high ammonia level. The patient was diagnosed with fulminant hepatic failure and transferred immediately to the medical intensive care unit, where he died 4 days later.

Antituberculosis drug-induced hepatotoxicity in children

Recent increases in the dosages of the essential antituberculosis agents isoniazid (INH), rifampicin (RMP), pyrazinamide (PZA) for use in children recommended by World Health Organization have raised concerns regarding the risk of hepatotoxicity. Published data relating to the incidence and pathogenesis of antituberculosis drug-induced hepatotoxicity (ADIH), particularly in children, is reviewed. Amongst 12,708 children receiving chemoprophylaxis, mainly with INH, but also other combinations of INH, RMP and PZA only 1 case (0.06%) of jaundice was recorded and abnormal liver functions documented in 110 (8%) of the 1225 children studied. Excluding tuberculous meningitis (TBM) 8984 were children treated for tuberculosis disease and jaundice documented in 75 (0.83%) and abnormal liver function tests in 380 (9.9%) of the 3855 children evaluated. Amongst 717 children treated for TBM, however, jaundice occurred in 72 (10.8%) and abnormal LFT were recorded in 174 (52.9%) of those studied. Case reports document the occurrence of ADIH in at least 63 children. Signs and symptoms of ADIH were frequently ignored in the recorded cases. ADIH can occur in children at any age or at any dosage of INH, RMP or PZA, but the incidence of.ADIH is is considerably lower in children than in adults. Children with disseminated forms of disease are at greater risk of ADIH. The use of the higher dosages of INH, RMP and PZA recently recommended by WHO is unlikely to result in a greater risk of ADIH in children.

[Specific features of tuberculosis in childhood]

Primary infection with Mycobacterium tuberculosis usually occurs during childhood. The source of infection is most often an adult. The risk of infection in exposed children is modulated by various factors related to the infectiousness of the index case, exposure conditions, and the child himself. This review aims to describe the specific diagnostic and therapeutic features of latent TB infection and TB disease in childhood.

Latent tuberculosis in children: diagnosis and management

Control of tuberculosis in children often escapes attention because of the paucibacillary nature of the illness. However, they contribute much of the morbidity, mortality and future reservoir of the disease which reiterates the importance of risk-factor based screening for latent infection and appropriate treatment. We review the modalities and importance of diagnosis and treatment of latent tuberculosis infection in children. At this time, the role for interferon-gamma release assays in low-income, high-burden settings is rather limited but further research in the coming years might clear their role in children. An important emerging area of research is the development of an improved skin test for TB that uses specific mycobacterial antigens rather than tuberculin, thus is more feasible and useful in resource limited settings.

[Latent tuberculosis infection treatment. Current recommendations]

Diagnosis and treatment of latent infection with Mycobacterium tuberculosis (LTBI), significantly reduces the risk of developing active tuberculosis and the transmission of the disease in the community. LTBI screening must pass by the exclusion of active disease (symptoms enquiry and chest radiography) and assessment of immune response to Mycobacterium tuberculosis testing with the tests currently available - tuberculin skin test and interferon -gamma release assay (IGRA). The choice of treatment must take into account the efficacy and side effects associated with the same. This document provides updated recommendations on latent tuberculosis infection treatment. Topics covered include whom to test for TB and reviewed LTBI treatment regimens.

A relook at preventive therapy for tuberculosis in children

Preventive therapy for tuberculosis in children is an important strategy to control pediatric TB in addition to early diagnosis and treatment of infectious cases in the community. In low burden countries, it is an important tool for preventing TB at all ages as the opportunities for re-infection are few. In contrast in high burden countries, preventive therapy though effective in preventing occurrence of disease among infected, can not prevent re-infection--an event of fairly high occurrence in these settings. Children under 5 years of age or immuno-compromised children of any age who have the highest risk of developing infection and disease when exposed are the main focus for preventive therapy in high burden settings. A 6 months therapy with INH continues to be the preferred modality of preventive therapy as efforts are being made to identify a short course preventive therapy using Rifampicin and other drugs.

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.

Childhood tuberculosis: an emerging and previously neglected problem

Although awareness is growing, childhood tuberculosis (TB) remains a neglected disease in many resource-limited settings. In part this reflects operational difficulties, lack of visibility in official reports, as well as perceptions that children tend to develop mild disease, contribute little to disease transmission, and do not affect epidemic control. At an international level there is greater appreciation that children contribute significantly to the global TB disease burden and suffer severe TB-related morbidity and mortality, particularly in TB-endemic areas, where the disease often remains undiagnosed. However, this is not always the case at the national or local level and there remains an urgent need for feasible and implementable policies to guide clinical practice. Pediatric TB can be regarded as an emerging epidemic in areas where the adult epidemic remains out of control and Mycobacterium tuberculosis transmission is ongoing. This article reviews important concepts, challenges, and management principles related to childhood TB; it also summarizes the main priorities for future research.

The use of anti-tuberculosis therapy for latent TB infection

Tuberculosis infection is of global public health significance, with millions of incident cases each year. Many cases, particularly in low-prevalence settings, result from the reactivation of latent tuberculosis infection (LTBI); potentially acquired years prior to active disease. Up to one-third of the world’s population has been infected with LTBI, and so may be at risk for future active TB disease. A variety of antituberculosis medications and treatment regimens have now been evaluated in the management of LTBI, with the aim of eradicating tuberculosis bacilli and reducing the likelihood of subsequent reactivation disease. This article reviews LTBI therapies and their use in clinical contexts, and considers future directions for individual and population-based strategies in LTBI management.

Current development and future prospects in chemotherapy of tuberculosis

Although treatment of drug-susceptible tuberculosis (TB) under ideal conditions may be successful in >or=95% of cases, cure rates in the field are often significantly lower due to the logistical challenges of administering and properly supervising the intake of combination chemotherapy for 6-9 months. Success rates are far worse for multidrug-resistant and extensively drug-resistant TB cases. There is general agreement that new anti-TB drugs are needed to shorten or otherwise simplify treatment for drug-susceptible and multidrug-resistant/extensively drug-resistant-TB, including TB associated with HIV infection. For the first time in over 40 years, a nascent pipeline of new anti-TB drug candidates has been assembled. Eleven candidates from seven classes are currently being evaluated in clinical trials. They include novel chemical entities belonging to entirely new classes of antibacterials, agents approved for use against infections other than TB, and an agent already approved for limited use against TB. In this article, we review the current state of TB treatment and its limitations and provide updates on the status of new drugs in clinical trials. In the conclusion, we briefly highlight ongoing efforts to discover new compounds and recent advances in alternative drug delivery systems.

Global tuberculosis drug development pipeline: the need and the reality

Drugs for tuberculosis are inadequate to address the many inherent and emerging challenges of treatment. In the past decade, ten compounds have progressed into the clinical development pipeline, including six new compounds specifically developed for tuberculosis. Despite this progress, the global drug pipeline for tuberculosis is still insufficient to address the unmet needs of treatment. Additional and sustainable efforts, and funding are needed to further improve the pipeline. The key challenges in the development of new treatments are the needs for novel drug combinations, new trial designs, studies in paediatric populations, increased clinical trial capacity, clear regulatory guidelines, and biomarkers for prediction of long-term outcome. Despite substantial progress in efforts to control tuberculosis, the global burden of this disease remains high. To eliminate tuberculosis as a public health concern by 2050, all responsible parties need to work together to strengthen the global antituberculosis drug pipeline and support the development of new antituberculosis drug regimens.

Evaluation of a school-based program for diagnosis and treatment of latent tuberculosis infection in immigrant children

OBJECTIVE

To evaluate a 10-year school-based latent tuberculosis infection (LTBI) screening program, targeting immigrant children in Montreal, Canada, and to identify predictive factors for refusal and, poor adherence to treatment.

METHODS

Immigrant children were screened for LTBI with Tuberculin Skin Test (TST). Isoniazid was, given when LTBI was diagnosed. Predictors of LTBI, of refusal of follow-up and treatment and of poor, adherence to isoniazid were analyzed.

RESULTS

Four thousand three hundred and seventy-five children were offered screening, 82.3% consented to TST and 22.8% were positive. An, older age at migration (odds ratio (OR)=1 [95% CI: 1.0-1.01]), as well as migration from a none, established market economy country (OR varying from 2.41 to 4.23) were significantly associated with, positive TST. Among positive children, further evaluation was refused in 5.7%, mainly in migrants from, Eastern Europe (OR=4.05 [95% CI: 2.14-7.69]). Refusal of treatment (11.2%) was more frequent in, Eastern European when compared to South-eastern Asian (OR=6.91 [95% CI: 1.56-30.75]), in, blended families (OR=3.25 [95% CI: 1.25-8.46]) and when the first visit to hospital was delayed (OR=1.01 [95% CI: 1.0-1.02]). Adequate completion of treatment was noted in 61.3%. Age>16 years (OR=1.82 [95% CI: 1.82-2.99]), a delay between TST and first visit>15 days (OR=1.6 [95% CI: 1.12-2.28]), as well as the presence of relative>18 years in the household (OR=1.56 [95% CI: 1.0-2.43]), were associated with poor adherence to treatment.

CONCLUSION

Sociocultural and behavioural factors are involved in acceptance of LTBI treatment in, immigrant children. Adherence to treatment is challenging and requires comperhension of sociocultural beliefs and accessibility to TB clinic.

[Consensus document on the diagnosis, treatment and prevention of tuberculosis]

Pulmonary TB should be suspected in patients with respiratory symptoms longer than 2-3 weeks. Immunosuppression may modify clinical and radiological presentation. Chest X-ray shows very suggestive, albeit sometimes atypical, signs of TB. Complex radiological tests (CT scan, MR) are more useful in extrapulmonary TB. At least 3 serial representative samples of the clinical location are used for diagnosis whenever possible. Bacilloscopy and liquid medium cultures are indicated in all cases. Genetic amplification techniques are coadjuvant in moderate or high TB suspicion. Administration of isoniazid, rifampicin, ethambutol and pyrazinamide (HREZ) for 2 months and HR for 4 additional months is recommended in new cases of TB, except in cases of meningitis in which treatment should continue for up to 12 months and up to 9 months in spinal TB with neurological involvement, and in silicosis. Appropriate adjustments with antiretroviral treatment should be made in HIV patients. Combined therapy is recommended to avoid development of resistance. An antibiogram to first line drugs should be performed in all the initial isolations of new patients. Treatment control is one of the most important activities in TB management. The Tuberculin Skin Test (TST) is positive in TB infection when >or=5mm, and Interferon-Gamma Release Assays (IGRA) are recommended in combination with TT. The standard treatment schedule for infection is 6 months with isoniazid. In pulmonary TB, respiratory isolation is applied for 3 weeks or until 3 negative bacilloscopy samples are obtained.

[Consensus document on the diagnosis, treatment and prevention of tuberculosis]

Pulmonary TB should be suspected in patients with respiratory symptoms longer than 2-3 weeks. Immunosuppression may modify clinical and radiological presentation. Chest x-ray shows very suggestive, albeit sometimes atypical, signs of TB. Complex radiological tests (CT scan, MR) are more useful in extrapulmonary TB. At least 3 serial representative samples of the clinical location are used for diagnosis whenever possible. Bacilloscopy and liquid medium cultures are indicated in all cases. Genetic amplification techniques are coadjuvant in moderate or high TB suspicion. Administration of isoniazid, rifampicin, ethambutol and pyrazinamide (HREZ) for 2 months and HR for 4 additional months is recommended in new cases of TB, except in cases of meningitis in which treatment should continue for up to 12 months and up to 9 months in spinal TB with neurological involvement, and in silicosis. Appropriate adjustments with antiretroviral treatment should be made in HIV patients. Combined therapy is recommended to avoid development of resistance. An antibiogram to first line drugs should be performed in all the initial isolations of new patients. Treatment control is one of the most important activities in TB management. The Tuberculin Skin Test (TST) is positive in TB infection when >or=5mm, and Interferon-Gamma Release Assays (IGRA) are recommended in combination with TT. The standard treatment schedule for infection is 6 months with isoniazid. In pulmonary TB, respiratory isolation is applied for 3 weeks or until 3 negative bacilloscopy samples are obtained.

Toward an optimized therapy for tuberculosis? Drugs in clinical trials and in preclinical development

Tuberculosis (TB) continues to be one of the greatest challenges in the global public health arena. Current therapeutic agents against TB are old and inadequate, particularly in the face of many new challenges. Multidrug-resistant TB (MDR-TB) has become prevalent in many parts of the world and extensively drug-resistant TB (XDR-TB) is rapidly emerging. There are few or essentially no effective drugs available to treat these drug-resistant forms of TB. TB and human immunodeficiency virus (HIV) coinfection has become another major problem in areas with high prevalence of HIV infection. Simultaneous treatment of TB and HIV is difficult due to the severe drug-drug interactions between the first-line rifamycin-containing TB therapy and antiretroviral agents. However, there have been some encouraging developments in TB drug research and development within the past decade. At present there are 6 compounds, including 3 novel agents, in late stages of clinical development. There are even larger numbers of compounds and projects in the TB drug pipeline at the discovery stage and in early stages of clinical development, mainly targeting treatment shortening and drug resistance. Despite these encouraging developments, the current TB drug pipeline is not sufficient to address the multitude of challenges inherent in the current standard of TB therapy. A stronger TB drug pipeline and a new paradigm for the development of novel TB drug combinations are needed.

Short-course therapy with daily rifapentine in a murine model of latent tuberculosis infection

RATIONALE

Regimens recommended to treat latent tuberculosis infection (LTBI) are 3 to 9 months long. A 2-month rifampin+pyrazinamide regimen is no longer recommended. Shorter regimens are highly desirable. Because substituting rifapentine for rifampin in the standard regimen for active tuberculosis halves the treatment duration needed to prevent relapse in mice, we hypothesized daily rifapentine-based regimens could shorten LTBI treatment to 2 months or less.

OBJECTIVES

To improve an existing model of LTBI chemotherapy and evaluate the efficacy of daily rifapentine-based regimens.

METHODS

Mice were immunized with a more immunogenic recombinant Bacille Calmette-Guérin strain (rBCG30) and received very low-dose aerosol infection with Mycobacterium tuberculosis to establish a stable lung bacterial burden below 10(4) CFU without drug treatment. Mice received a control (isoniazid alone, rifampin alone, rifampin+isoniazid, rifampin+pyrazinamide) or test (rifapentine alone, rifapentine+isoniazid, rifapentine+pyrazinamide, rifapentine+isoniazid+pyrazinamide) regimen for 8 weeks. Rifamycin doses were 10 mg/kg/d, analogous to the same human doses. Outcomes were biweekly lung CFU counts and relapse after 4 to 8 weeks of treatment.

MEASUREMENTS AND MAIN RESULTS

M. tuberculosis CFU counts remained stable around 3.65 log(10) in immunized, untreated mice. Isoniazid or rifampin left all or most mice culture-positive at week 8. Rifampin+isoniazid cured 0 and 53% of mice and rifampin+pyrazinamide cured 47 and 100% of mice in 4 and 8 weeks, respectively. Rifapentine-based regimens were more active than rifampin+isoniazid and indistinguishable from rifampin+pyrazinamide.

CONCLUSIONS

In this improved murine model of LTBI chemotherapy with very low lung burden, existing regimens were well represented. Daily rifapentine-based regimens were at least as active as rifampin+pyrazinamide, suggesting they could effectively treat LTBI in 6 to 8 weeks.

Pediatric TB: issues related to current and future treatment options

Pediatric TB continues to be a neglected disease in many endemic areas where limited resources restrict the focus of treatment to only the most infectious TB cases. However, recognition that children contribute to a significant proportion of the global TB disease burden and suffer severe TB-related morbidity and mortality is growing. The WHO published guidelines on the management of pediatric TB in 2006 and child-friendly drug formulations have been made available to deserving low-income nations via the Global Drug Fund since 2008. Increased awareness and improved drug availability re-emphasized the considerable programmatic barriers that remain and the difficulty of establishing an accurate diagnosis in resource-limited settings. This article provides an overview of current treatment practices, factors that influence the provision of effective TB therapy to children in endemic areas and potential future advances. It includes a brief summary of the relevant literature and presents the authors’ personal perspectives on issues related to the treatment of pediatric TB.

Preventing tuberculosis flare in patients with inflammatory rheumatic diseases receiving tumor necrosis factor-alpha inhibitors in India -- An audit report

OBJECTIVE

To test the efficacies of a strategy for preventing tuberculosis (TB) in Indian patients with inflammatory rheumatic diseases (IRD) treated with tumor necrosis factor-alpha (TNF-alpha) inhibitor.

METHODS

The screening strategy included tuberculosis skin test (TST), QuantiFERON-TB Gold (QTG) test, standard chest radiograph, and contrast enhanced-computerized tomography of the chest (CT).

RESULTS

Among 53 patients screened, 17 (32%) had >or= 1 test positive, with 5 (9.4%) patients having TB infection (clinical, CT, biopsy). The remaining 12 patients showed latent TB; 1 additional patient with negative screening tests was diagnosed with latent TB retrospectively for he developed TB disease within a few weeks of receiving infliximab. The remaining 35 patients tested negative with all tests. The combination of 4 screening tests gave a sensitivity of 0.83, specificity of 0.74, positive predictive value (PPV) 0.29, and negative predictive value (NPV) 0.97. Only 22 patients could afford treatment with TNF-alpha inhibitors; 19 of them were negative in the screening tests. Three patients who were positive on TST and/or QTG received prophylactic treatment with TNF-alpha inhibitor. Since implementation of the screening strategy, only 1 of 22 (4.5%) patients given TNF-alpha inhibitor developed probable TB disease.

CONCLUSION

With the use of these 4 TB screening tests in India, where TB is highly prevalent, TB could be excluded with a high degree of certainty (NPV 0.97). However, as even this combination of tests has only moderate sensitivity and specificity and poor PPV for detecting TB, vigilance may be advisable even if only one of the tests is positive.

Latent tuberculosis infection in children: a call for revised treatment guidelines

BACKGROUND

Guidelines for latent tuberculosis infection do not consider drug-resistance patterns when recommending treatment for immigrant children.

OBJECTIVES

The purpose of this research was to decide at what rate of isoniazid resistance a different regimen other than isoniazid for 9 months should be considered.

METHODS

We constructed a decision tree by using published data. We studied 3 regimens considered to be effective for susceptible organisms: (1) isoniazid for 9 months, (2) rifampin for 6 months, and (3) isoniazid for 9 months plus rifampin for 6 months. In addition, we evaluated a regimen of isoniazid and rifampin for 3 months. Our base case was a 2-year-old child from Russia with a tuberculin skin test reaction of 12 mm. We assumed a societal perspective and expressed results as cost and cost per case of tuberculosis prevented. We conducted sensitivity analyses to test the stability of our model.

RESULTS

In our baseline analysis, rifampin was the least costly treatment regimen for any child arriving from an area with an isoniazid-resistance rate of >/=11%. Treatment with isoniazid plus rifampin was the most effective but would cost more than $1 million per reactivation case prevented. Isoniazid would become the least costly regimen if any of the following thresholds were met: rifampin resistance given isoniazid resistance of more than 82%; rifampin resistance given no isoniazid resistance of >9%; cost of rifampin more than $47/month; effectiveness of rifampin lower than 63%; effectiveness of isoniazid higher than 74%; and cost of pulmonary tuberculosis less than $7661. Isoniazid and rifampin for 3 months was the least costly for all cases from areas with isoniazid resistance of <80% as long as the regimen's effectiveness was >50% for susceptible bacteria. However, this assumption remains to be proven.

CONCLUSION

Because of the high prevalence of isoniazid resistance, rifampin should be considered for children with latent tuberculosis infection originating from countries with >11% isoniazid resistance.

Treatment of tuberculosis in children

The treatment of children with TB is influenced by a number of factors specific to both the bacterium and the child. We review the variables impacting the selection of individual medications; indications, pharmacology, dosing and side effects for first- and second-line agents; adjunctive therapy; and special cases, including treatment of TB in HIV-infected children and multidrug-resistant TB. Finally, evolving trends in TB therapy, such as the impact of HIV and multidrug-resistant TB on future therapeutics, emerging or re-emerging medication options, shorter-course regimens and immunomodulation, are discussed.

Proposed management of childhood tuberculosis in low-incidence countries

The incidence of childhood tuberculosis continues to decline in central Europe, but due to migration from high incidence countries paediatricians will still be confronted with it. The management of childhood tuberculosis in low-incidence, high-income countries differs from most high-incidence countries. The primary measures for preventing the transmission of tuberculosis to children are the detection of adult source cases, detection of latent TB infection (LTBI) in children by history, tuberculin skin testing and, if necessary and recommended, interferon-gamma release assays. Children with LTBI should receive preventive therapy. The inclusion of tuberculosis in the differential diagnosis of unclear pulmonary and extrapulmonary disease remains important, and tuberculosis has to be managed according to international standards.

Assessment by time-kill methodology of the synergistic effects of oritavancin in combination with other antimicrobial agents against Staphylococcus aureus

Oritavancin is a semisynthetic lipoglycopeptide in clinical development for serious gram-positive infections. This study describes the synergistic activity of oritavancin in combination with gentamicin, linezolid, moxifloxacin, or rifampin in time-kill studies against methicillin-susceptible, vancomycin-intermediate, and vancomycin-resistant Staphylococcus aureus.

Symptom-based screening of child tuberculosis contacts: improved feasibility in resource-limited settings

OBJECTIVE

National tuberculosis programs in tuberculosis-endemic countries rarely implement active tracing and screening of child tuberculosis contacts, mainly because of resource constraints. We aimed to evaluate the safety and feasibility of applying a simple symptom-based approach to screen child tuberculosis contacts for active disease.

METHODS

We conducted a prospective observational study from January through December 2004 at 3 clinics in Cape Town, South Africa. All of the children <5 years old in household contact with an adult tuberculosis source case were assessed by documenting current symptoms and tuberculin skin test and chest radiograph results.

RESULTS

During the study period, 357 adult tuberculosis cases were identified; 195 cases (54.6%) had sputum smear and/or culture positive results and were in household contact with children aged <5 years. Complete information was available for 252 of 278 children; 176 (69.8%) were asymptomatic at the time of screening. Tuberculosis treatment was administered to 33 (13.1%) of 252; 27 were categorized as radiologically "certain tuberculosis," the majority (n = 22) of which had uncomplicated hilar adenopathy. The negative predictive value of symptom-based screening varied according to the case definition used, with 95.5% including all of the children treated for tuberculosis and 97.1% including only those with radiologically "certain tuberculosis."

CONCLUSIONS

Our findings support current World Health Organization recommendations, demonstrating that symptom-based screening of child tuberculosis contacts should improve feasibility in resource-limited settings and seems to be safe.

Tuberculosis in children

Tuberculosis (TB) control poses one of the major global health challenges in the new millennium. Children in TB-endemic areas suffer severe TB related morbidity and mortality, despite the availability of cheap and effective TB treatment. However, providing an accurate TB diagnosis together with access to supervised, child friendly treatment remains difficult in resource-limited settings. This review provides a broad overview of recent advances related to child TB, focusing on intra-thoracic disease manifestations. It summarizes current understanding of TB epidemiology, disease prevention, diagnosis and treatment, but also introduces novel concepts for further discussion and future evaluation.

Completion of therapy for latent tuberculosis in children of different nationalities

We performed a retrospective review of prospectively stored data on 545 children from 54 different birth countries with latent tuberculosis cared for in a pediatric tuberculosis clinic between August 1, 2005 and July 31, 2006. For analysis, patients were grouped into 6 geographic regions. The overall rate of completion of therapy was 54.4%. There were no significant differences among regions in the rate of completion of therapy by age, duration in the United States, or exposure to active tuberculosis. However, no children from Eastern Europe completed therapy compared with 67.9% from Central and South America. Of those children who did not complete therapy, parental refusal to start medication accounted for 54% and 80% of Eastern European and Asian children compared with <10% of children from Sub-Saharan Africa, Central and South America, and the United States.