Efficacies of clarithromycin regimens against Mycobacterium xenopi in mice

Pharmacotherapy for nontuberculous mycobacterial pulmonary disease

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PURPOSE

To provide an updated review of the diagnosis and pharmacotherapy of nontuberculous mycobacteria pulmonary disease (NTM-PD) and summarize guideline recommendations for an interdisciplinary treatment approach.

SUMMARY

A systemic approach was taken in which all articles in English in MEDLINE and PubMed were reviewed. DAILYMED was used to assess drug package inserts. Analysis of NTM treatment guidelines is summarized in the article with a focus on medications, dosing, interactions, and medication monitoring.

CONCLUSION

It is critical to manage patients with NTM with a multidisciplinary team approach. Treatment is prolonged and expensive, and the potential for drug toxicity, adverse effects, and drug interactions requires monitoring. Clinical pharmacists play a role in the management of NTM.

Treatment of Nontuberculous Mycobacterial Pulmonary Disease: An Official ATS/ERS/ESCMID/IDSA Clinical Practice Guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

Treatment of nontuberculous mycobacterial pulmonary disease: an official ATS/ERS/ESCMID/IDSA clinical practice guideline

Nontuberculous mycobacteria (NTM) represent over 190 species and subspecies, some of which can produce disease in humans of all ages and can affect both pulmonary and extrapulmonary sites. This guideline focuses on pulmonary disease in adults (without cystic fibrosis or human immunodeficiency virus infection) caused by the most common NTM pathogens such as Mycobacterium avium complex, Mycobacterium kansasii, and Mycobacterium xenopi among the slowly growing NTM and Mycobacterium abscessus among the rapidly growing NTM. A panel of experts was carefully selected by leading international respiratory medicine and infectious diseases societies (ATS, ERS, ESCMID, IDSA) and included specialists in pulmonary medicine, infectious diseases and clinical microbiology, laboratory medicine, and patient advocacy. Systematic reviews were conducted around each of 22 PICO (Population, Intervention, Comparator, Outcome) questions and the recommendations were formulated, written, and graded using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. Thirty-one evidence-based recommendations about treatment of NTM pulmonary disease are provided. This guideline is intended for use by healthcare professionals who care for patients with NTM pulmonary disease, including specialists in infectious diseases and pulmonary diseases.

A case of pulmonary Mycobacterium heckeshornense infection in a healthy Japanese man

A 72-year-old man, healthy, smoker, with long-standing cough, was referred to our hospital and his chest X-ray (CXR) revealed a cavity lesion in the right upper lobe. Direct sputum smears, but not culture in solid medium, were positive for acid-fast bacilli (AFB) without tuberculosis DNA. The preliminary diagnosis was of a non-tuberculosis infection that progressed slowly, and the CXR showed the condition to worsen daily. Four years later, a commercialized mycobacteria growth indicator tube system was used to culture the colonies of AFB successfully in liquid medium, and the species Mycobacterium heckeshornense was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The patient responded well to triple therapy with rifampicin, ethambutol, and clarithromycin, the sputum cultures remained negative and the roentgenogram showed minor improvement over the following 6 months.

Pharmacokinetics, tissue distribution and relative bioavailability of isoniazid-solid lipid nanoparticles

Low levels of isoniazid gain access into plasma following oral administration due to its high aqueous solubility, poor permeability and rapid and extensive hepatic metabolism. Further, a small t(1/2) of 1-4 h indicates its short stay in plasma and the need for repetitive or high doses which may subsequently result in hepatotoxicity and neurotoxicity associated with its use. Isoniazid-solid lipid nanoparticles (SLNs) were prepared to achieve improved bioavailability and prolonged effect, thus minimizing pulsatile plasma concentrations (and associated side effects at peak plasma concentrations). Developed SLNs showed high entrapment efficiency (69%) and small size (d(90) 48.4 nm) such that they are expected to bypass reticulo-endothelial system (RES) pickup resulting in prolonged circulation times and since liver is the major site of metabolism of isoniazid, RES avoidance will reduce its elimination from the body. Single dose (25 mg/kg BW) oral pharmacokinetic studies were performed in plasma and various tissues of rats. A significant improvement (p<0.001) in relative bioavailability in plasma (6 times) and brain (4 times) was observed after administration of isoniazid-SLNs with respect to the free drug solution at the same dose. Insignificant changes in liver concentration coupled with bypass of first pass metabolism and slow release of isoniazid (60%, in 24 h) indicate low incidence of hepatotoxicity. Isoniazid-SLNs showed a 3 times higher LD50.

Improving existing tools for Mycobacterium xenopi treatment: assessment of drug combinations and characterization of mouse models of infection and chemotherapy

BACKGROUND

Mycobacterium xenopi is a common agent of non-tuberculous mycobacterial lung diseases in Europe. However, an optimal treatment regimen for M. xenopi infection has not yet been established. Appropriate in vitro and in vivo model systems are needed for characterization of the activity of potential drugs and drug combinations against M. xenopi.

METHODS

We utilized three experimental platforms to analyse the anti-M. xenopi activity of single and combination drug regimens. First, we determined the bacteriostatic and bactericidal activities of drugs alone and in combination in vitro. Second, we used serum from treated mice to evaluate drug activities ex vivo. Third, we analysed M. xenopi growth in four strains of mice (BALB/c, C57BL/6, beige and athymic nude) and developed a mouse model of chemotherapy for this infection.

RESULTS

Two-drug combinations of ethambutol with rifampicin, rifapentine or moxifloxacin, and of clarithromycin with moxifloxacin were bactericidal in vitro, and the combination of ethambutol and rifampicin with either clarithromycin or moxifloxacin showed significant bactericidal activity ex vivo. Nude mice were the most susceptible strain to M. xenopi infection, and in this model amikacin-containing regimens were the most effective against M. xenopi. No difference in activity was found between regimens containing clarithromycin and moxifloxacin in vivo.

CONCLUSION

The ethambutol/rifampicin combination with clarithromycin or moxifloxacin had significant bactericidal activity against M. xenopi. The nude mouse, being highly susceptible to M. xenopi, can be utilized for in vivo chemotherapy studies for this infection.

[Diagnosis and treatment of atypical mycobacterial infections of the respiratory tract]

INTRODUCTION

Non tuberculous mycobacteria (NTM), unlike tuberculous mycobacteria, are not strictly human pathogens. The diagnosis of infection and the choice of treatment remain difficult.

BACKGROUND

Evidence of a NTM in a pulmonary sample is not synonymous with infection. The diagnosis depends on the association of clinical, radiological and microbiological factors. If a NTM is isolated from a respiratory sample, the probability of infection depends on the species. The main NTMs responsible for pulmonary infection in France are Mycobacterium avium intracellulare, Mycobacterium xenopi, Mycobacterium kansasi and Mycobacterium abscessus. Their management is difficult and poorly understood. Treatment is well established for M. avium intracellulare and M. kansasii, with combinations of clarithromycin-rifampicin-ethambutol and isoniazid-rifampicin-ethambutol respectively. For M. xenopi, the optimal treatment is not known and a combination of clarithromycin-rifampicin-ethambutol, with moxifloxacin as an alternative, is currently recommended. In general, treatment is prolonged and often associated with problems of tolerance.

VIEWPOINT AND CONCLUSION

The management of NTM infection, taking into account of the increase in patients "at risk", is an important issue. Further studies are needed to improve the criteria for infection and to find the optimal therapeutic combinations.

Current treatment of atypical mycobacteriosis

BACKGROUND

Atypical mycobacteria are a heterogeneous group of organisms that are of increasing importance because of the growing number of infections they cause. This rising rate of infection is due mainly to the increase in the number of susceptible (and especially immunosuppressed) patients.

OBJECTIVE

To revise the currently used treatment schemes of the most commonly isolated atypical mycobacteria.

METHODS

Literature review using reference books and PubMed with specific keywords for each mycobacteria.

RESULTS/CONCLUSION

The first important step in the management of atypical mycobacteria is to recognize the true infections caused by these organisms. The treatment required varies according to species. Well-characterized combinations exist for most common isolates, with the use of first-line antituberculous drugs (isoniazid, rifampin, ethambutol), clarithromycin, aminoglycosides and/or quinolones for slowly growing species (Mycobacterium avium complex, Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium ulcerans, Mycobacterium marinum, Mycobacterium lentiflavum, Mycobacterium malmoense) and macrolides, quinolones, amikacin and other antibiotics for rapidly growing mycobacteria (Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum). Surgical therapy is also important for some species (Mycobacterium ulcerans, Mycobacterium scrofulaceum) and for localized infections. The treatment of uncommon species is not well defined and is determined by the results of in vitro tests of individual strains. Because of the increasing number of resistant strains, new antibiotics need to be used for the treatment of these strains.

Structure-activity relationships of macrolides against Mycobacterium tuberculosis

Existing 14, 15 and 16-membered macrolide antibiotics, while effective for other bacterial infections, including some mycobacteria, have not demonstrated significant efficacy in tuberculosis. Therefore an attempt was made to optimize this class for activity against Mycobacterium tuberculosis through semisyntheses and bioassay. Approximately 300 macrolides were synthesized and screened for anti-TB activity. Structural modifications on erythromycin were carried out at positions 3, 6, 9, 11, and 12 of the 14-membered lactone ring; as well as at position 4'' of cladinose and position 2' of desosamine. In general, the synthesized macrolides belong to four subclasses: 9-oxime, 11,12-carbamate, 11,12-carbazate, and 6-O-substituted derivatives. Selected compounds were assessed for mammalian cell toxicity and in some cases were further assessed for CYP3A4 inhibition, microsome stability, in vivo tolerance and efficacy. The activity of 11,12-carbamates and carbazates as well as 9-oximes is highly influenced by the nature of the substitution at these positions. For hydrophilic macrolides, lipophilic substitution may result in enhanced potency, presumably by enhanced passive permeation through the cell envelope. This strategy, however, has limitations. Removal of the C-3 cladinose generally reduces the activity. Acetylation at C-2' or 4'' maintains potency of C-9 oximes but dramatically decreases that of 11,12-substituted compounds. Further significant increases in the potency of macrolides for M. tuberculosis may require a strategy for the concurrent reduction of ribosome methylation.

Pulmonary disease caused by Mycobacterium xenopi: the first case in Korea

Mycobacterium xenopi is a nontuberculous mycobacterium (NTM) that rarely causes pulmonary disease in Asia. Here we describe the first case of M. xenopi pulmonary disease in Korea. A 66-year-old man was admitted to our hospital with a 2-month history of productive cough and hemoptysis. His past medical history included pulmonary tuberculosis 44 years earlier, leading to a right upper lobectomy. Chest X-ray upon admission revealed cavitary consolidation involving the entire right lung. Numerous acid-fast bacilli were seen in his initial sputum, and M. xenopi was subsequently identified in more than five sputum cultures, using molecular methods. Despite treatment with clarithromycin, rifampicin, ethambutol, and streptomycin, the infiltrative shadow revealed on chest X-ray increased in size. The patient's condition worsened, and a right completion pneumonectomy was performed. The patient consequently died of respiratory failure on postoperative day 47, secondary to the development of a late bronchopleural fistula. This case serves as a reminder to clinicians that the incidence of NTM infection is increasing in Korea and that unusual NTM are capable of causing disease in non-immunocompromised patients.

Non-tuberculous mycobacteria pulmonary infection: Management and follow-up of 31 infected patients

BACKGROUND

The global number of non-tuberculous mycobacteria (NTM) pulmonary infections is increasing. Treatment decisions and management are difficult and the prognosis of these infections has been rarely evaluated.

METHODS

The aim of this study was to evaluate management and prognosis of patients with NTM pulmonary infection in a French teaching hospital. In this study, we evaluated management of patients satisfying the ATS (American Thoracic Society) criteria for NTM pulmonary infection in Amiens hospital from 1992 to 2002 and retrospectively compared this management to ATS guidelines. Short-term and long-term survival was also described.

RESULTS

Thirty-one patients satisfying the ATS criteria for NTM pulmonary infection were included: 15 patients were infected with Mycobacterium xenopi, nine with Mycobacterium avium intracellulare, four with Mycobacterium kansasii and three patients were infected with rapidly growing mycobacteria. Twenty-seven patients had past or concomitant diseases responsible for local or systemic immunosuppression. Eleven patients were not treated. In the 20 treated patients, 13 different antibiotic combinations were used, often comprising three or more drugs. The median survival was 15 months. Twenty-one patients (67%) died before 5 years of follow-up. Thirty per cent of deaths were attributed to NTM pulmonary infection. Adjusting treatment to the results of susceptibility tests or ATS guidelines was not associated with any significant difference in survival.

CONCLUSION

As the high mortality rate may be related to concomitant diseases, management of NTM pulmonary infection also depends on comorbidities, and should be defined according to the severity of underlying diseases.

Effect of clarithromycin on the cell profile of bronchoalveolar lavage fluid in mice with neutrophil-predominant lung disease

OBJECTIVE

Macrolide antibiotics have anti-inflammatory properties in lung diseases. The aim of this study was to investigate the effect of clarithromycin in pulmonary cellular inflammatory response in mice.

METHOD

Eight adult Swiss mice were studied. All animals received an intranasal challenge (80 micro L) with dead Pseudomonas aeruginosa (1.0 x 10(12) CFU/mL). Bronchoalveolar lavage was performed 2 days later, with total cell count and differential cell analysis. The study group (n = 4) received clarithromycin treatment (50 mg/kg/day, intraperitoneal) for 5 days. Treatment was initiated 2 days before intranasal challenge.

RESULTS

There was no significant difference in total cell count between the groups (mean: 2.0 x 10(6) and 1.3 x 10(6), respectively). In both groups, there was a predominance of neutrophils. However, the study group had a higher percentage of lymphocytes in the bronchoalveolar lavage than the control group (median of 19% vs 2.5%, P =.029).

CONCLUSION

Clarithromycin alters the cytological pattern of bronchoalveolar lavage of Swiss mice with neutrophil pulmonary inflammation, significantly increasing the percentage of lymphocytes.

Human immunodeficiency virus type 1-related pulmonary Mycobacterium xenopi infection: a need to treat?

We report treatment decisions and outcomes for 20 patients who were infected with human immunodeficiency virus type 1 (HIV-1) and were receiving highly active antiretroviral therapy (HAART) who had respiratory symptoms and from whom Mycobacterium xenopi was isolated. All patients also had coexisting pulmonary pathologic conditions. The median blood T cell CD4 count was 37 cells/microL (range, 2-480 cells/microL). Fifteen of 20 patients received no antimycobacterial therapy and remain healthy after a median of approximately 4 years of follow-up, and 2 patients required treatment specifically for M. xenopi infection, both showing clinical improvement. We conclude that pulmonary M. xenopi isolation in HIV-1 patients receiving HAART does not usually require specific treatment.