Nontuberculous mycobacterial lung disease. Substantiation of a less aggressive approach

Efficacy and treatment outcome of infected patients with pulmonary Mycobacterium kansasii: A systematic review

Background

Mycobacterium kansasii (M. kansasii) is a non-tuberculosis bacterium with a highly prevalent that is transferred by aerosols from water and soil resources to the respiratory system. M. kansasii is one of the main species responsible for NTM pulmonary disease.

Methods

Web of Science, Scopus, and PubMed databases were systematically explored. Relevant articles from 1971 to November 2023 were reviewed. "The inclusion criteria" included patients with M. kansasii infection, treatment follow-up, and treatment outcomes. "The exclusion criteria" were clinical samples from animals, environmental samples, and other laboratory investigations.

Results

40 studies, including 1201 patients, were obtained through database search. Using the therapeutic regimens used in different studies, the therapy course for patients with M. kansasii infection ranged from 1 week to 118 months. In this study, the antibiotics prescribed in different treatment regimens for M. kansasii pulmonary infection were as follows: Rifampin, Ethambutol, Isoniazid, Clarithromycin, Streptomycin, and Pyrazinamide. Antibiotic combinations of three or four medicines, including rifampin, ethambutol, and isoniazid with or without streptomycin or pyrazinamide had the most therapeutic effect.

Conclusion

The initial treatment involves rifampin, ethambutol, isoniazid, and pyridoxine, per the guidelines from the American Thoracic Society (ATS) and the Infectious Diseases Society of America (IDSA). Understanding the treatment plan and its outcomes is crucial for managing and determining the most effective therapy approach.

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.

Treatment Outcomes of Mycobacterium avium Complex Lung Disease: A Systematic Review and Meta-analysis

Background

The advent of macrolides has led to therapeutic advances in the treatment of Mycobacterium avium complex lung disease (MAC-LD). The aim of this study was to elucidate the treatment outcomes of macrolide-containing regimens.

Methods

We performed a systematic review and meta-analysis of published studies reporting treatment outcomes of macrolide-containing regimens for MAC-LD using the Medline, Embase, and Cochrane Library databases through 31 July 2016. The rates of treatment success, default from treatment, and adverse events of macrolide-containing regimens were assessed. Treatment success was defined as either 12 months of sustained culture negativity while on therapy or achievement of culture conversion and completion of the planned treatment without relapse.

Results

In total, 16 studies involving 1462 patients were included. The rate of treatment success was 60.0% (95% confidence interval [CI], 55.1%-64.8%). The proportion of patients who defaulted from the treatment was 16.0% (95% CI, 12.3%-19.7%). When a thrice-weekly dosing schedule was available, the default rate was 12.0% (95% CI, 8.9%-15.0%). Adverse events necessitating treatment discontinuation or dosage modification of macrolides were observed in 6.4% of patients (95% CI, 3.2%-9.5%), and decreased auditory acuity was the most common adverse event.

Conclusions

Treatment outcomes of macrolide-containing regimens are relatively poor in terms of both the treatment success and default rates. The default rate could be reduced if a thrice-weekly dosing schedule is available. Clinicians should be aware of decreased auditory function as the most common adverse event associated with macrolide-containing regimens.

Identification of Pathogenic Factors in Klebsiella pneumoniae Using Impedimetric Sensor Equipped with Biomimetic Surfaces

K.pneumoniae is an opportunistic pathogen that causes nosocomial infections, such as, pneumonia, urinary tract infections, septic shock, and gastro intestinal disease. Lipopolysaccharide (LPS), capsular polysaccharide, and fimbriae are recognized major virulence factors of K.pneumoniae and play key roles during early stages of infections. In this study, we functionalized the surface of gold electrode with mannose and mucin to monitor the adhesion-associated virulence factors of K.pneumoniae. The binding characteristics of K.pneumoniae 2242 wild type and of its isogenic mutants lacking outer-core LPS (∆wabG) or fimbriae (∆fimA) were investigated using Faradaic impedance spectra. The results obtained showed fimbriae are responsible for K.pneumoniae adhesion to the mannose of glycoprotein on the surfaces of epithelial cells, whereas outer-core LPS and capsular polysaccharide are associated with specific binding to mucous. These results concurred with those of a conventional in vitro assay using human ileocecal epithelial cell (HCT-8 cells) and a human bladder epithelial cell (T-24), indicating that the devised method could be useful for investigating virulence-associated interactions of pathogenic bacteria with specific host cells and organs.

Inactivation of the virulence factors from 2,3-butanediol-producing Klebsiella pneumoniae

The microbiological production of 2,3-butanediol (2,3-BDO) has attracted considerable attention as an alternative way to produce high-value chemicals from renewable sources. Among the number of 2,3-BDO-producing microorganisms, Klebsiella pneumoniae has been studied most extensively and is known to produce large quantity of 2,3-BDO from a range of substrates. On the other hand, the pathogenic characteristics of the bacteria have limited its industrial applications. In this study, two major virulence traits, outer core LPS and fimbriae, were removed through homologous recombination from 2,3-BDO-producing K. pneumoniae 2242 to expand its uses to the industrial scale. The K. pneumoniae 2242 ∆wabG mutant strain was found to have an impaired capsule, which significantly reduced its ability to bind to the mucous layer and evade the phagocytic activity of macrophage. The association with the human ileocecal epithelial cell, HCT-8, and the bladder epithelial cell, T-24, was also reduced dramatically in the K. pneumoniae 2242 ∆fimA mutant strain that was devoid of fimbriae. However, the growth rate and production yield for 2,3-BDO were unaffected. The K. pneumoniae strains developed in this study, which are devoid of the major virulence factors, have a high potential for the efficient and sustainable production of 2,3-BDO.

Mycobacterium avium ss paratuberculosis-associated diseases: piecing the Crohn's puzzle together

The relation of Mycobacterium avium ss paratuberculosis (MAP) to Crohn's Disease (CD) and other MAP-associated conditions remains controversial. New data, coupled with the analogous Helicobacter pylori (H. pylori) story, has permitted us to piece together the MAP puzzle and move forward with a more scientific way of treating inflammatory bowel disease, particularly CD. As infection moves centre stage in inflammatory bowel disease, the dated "aberrant reaction" etiology has lost scientific credibility. Now, our growing understanding of MAP-associated diseases demands review and articulation. We focus here on (1) the concept of MAP-associated diseases; (2) causality, Johne Disease, the "aberrant reaction" hypothesis; and (3) responses to published misconceptions questioning MAP as a pathogen in CD.

Crohn's disease and the mycobacterioses: a quarter century later. Causation or simple association?

It has been more than 25 years since Mycobacterium paratuberculosis was first proposed as an etiologic agent in Crohn's disease based on the isolation of this organism from several patients. Since that time, a great deal of information has been accumulated that clearly establishes an association between M. paratuberculosis and Crohn's disease. However, data are conflicting and difficult to interpret and the field has become divided into committed advocates and confirmed skeptics. This review is an attempt to provide a thorough and objective summary of current knowledge from both basic and clinical research from the views and interpretations of both the antagonists and proponents. The reader is left to draw his or her own conclusions related to the validity of the issues and claims made by the opposing views and data interpretations. Whether M. paratuberculosis is a causative agent in some cases or simply represents an incidental association remains a controversial topic, but current evidence suggests that the notion should not be so readily dismissed. Remaining questions that need to be addressed in defining the role of M. paratuberculosis in Crohn's disease and future implications are discussed.

Mycobacterium avium complex pulmonary disease in patients with pre-existing lung disease

Patients with MAC-PD and pre-existing lung disease are a distinct group from the more common and recently recognized group of predominantly middle- to older-aged women without pre-existing lung disease. Those with pre-existing disease are expected to have more sputum positivity and slower conversion of sputum with treatment, and they may require combined medical treatment with surgical resection for optimal results. Attention to bronchial hygiene, avoidance of unnecessary use of macrolides, and treatment of underlying esophageal and lung disease can result in marked symptomatic improvement in many cases. Appropriate consideration must be given to mycobacterial antibiotic treatment, and awareness must be maintained for other processes such as bronchogenic cancer in select groups of high-risk patients.

Synthesis and antimycobacterial activity of new S-alkylisothiosemicarbazone derivatives

A new series of S-alkylisothiosemicarbazones of 3- and 4-pyridincarboxaldehyde and 4-fluoro- and 4-trifluoromethylbenzaldehyde was synthesized and evaluated for biological activity against various Mycobacterium strains. Inhibitory activity against Mycobacterium tuberculosis H37Rv ATCC 27294 and INH-R ATCC 35822 was compared with activity against clinical isolated Mycobacteria as well as against MOTT. Some of newly prepared compounds showed best inhibitory values against clinical isolated Mycobacteria, besides to low citotoxicity values.

Risk-benefit assessment of therapies for Mycobacterium avium complex infections

Mycobacterium avium complex (MAC) is an important pathogen that can cause chronic lung disease in immunocompetent patients and disseminated disease in patients with the acquired immunodeficiency syndrome (AIDS). Treatment of MAC with antituberculosis drugs was unsatisfactory, but the introduction of the newer macrolides, clarithromycin and azithromycin, and of rifabutin has greatly improved the outcome of treatment regimens for MAC. However, these agents are also associated with many new treatment-related adverse effects and potential drug-drug interactions. Rifamycins [rifampicin (rifampin) more than rifabutin] induce cytochrome P450 enzymes and accelerate the metabolism of clarithromycin and HIV protease inhibitors. Conversely, clarithromycin inhibits these enzymes, resulting in increased rifabutin toxicity. The net results are treatment regimens that may be extremely difficult to tolerate, especially for elderly or debilitated patients. Clarithromycin and azithromycin must be administered in combination with other agents such as ethambutol to prevent the emergence of macrolide resistance. Unfortunately, not all patients respond to the combination of a macrolide, rifabutin and ethambutol, and many have significant adverse effects (mostly gastrointestinal) with this regimen. For some patients the treatment is worse than the disease. The same 3-drug regimen is also effective therapy for disseminated MAC in AIDS patients, in whom the additional problem of a rifamycin/protease inhibitor interaction may be present. Fortunately, as opposed to pulmonary MAC disease in immunocompetent patients, disseminated MAC disease is a diminishing problem because of effective prophylactic regimens for MAC and improved antiretroviral therapy for HIV. Significant progress has been made in the treatment of MAC disease with the introduction of the newer macrolides. It is to be hoped that even better drugs that are more active against MAC and are associated with less toxicity and drug-drug interactions will be introduced in the future.

Paratuberculosis: a potential zoonosis?

Available literature on the controversial role of Mycobacterium paratuberculosis as an etiologic agent in human Crohn's disease is reviewed. Despite almost 15 years of investigation, the question of causal or consequential association between Johne's disease and Crohn's disease continues to linger.

Clarithromycin in the treatment of Mycobacterium avium lung infections in patients without AIDS. Clarithromycin Study Group of France

Mycobacterium avium complex infections, common in patients with AIDS as either pulmonary or disseminated disease, are infrequent in patients without AIDS. Participants were 45 HIV-negative patients with lung disease and positive sputum cultures for M avium; 10 had documented immunocompromise, and 24 had preexisting lung disease. Clarithromycin dosage was 500 to 2,000 mg daily (mean +/- SD = 1,633 +/- 432 mg). The drug was administered either alone (n = 14) or in combination with rifampin (n = 8), aminoglycoside (n = 1), quinolone (n = 10), clofazimine (n = 18), isoniazid (n = 5), ethambutol (n = 9), pyrazinamide (n = 1), or minocycline (n = 6). At 3 months, 36 patients among 39 bacteriologically assessed had negative sputum cultures, 3 had positive culture, 3 were dead, and 3 discontinued treatment. At the end of treatment, 32 patients remained negative, 7 were positive. The success rate was 15 of 22 (64%) in patients previously treated with antimycobacterial drugs for M avium disease and 17 of 23 (74%) in new patients. Adverse effects included mild hearing loss (n = 4), increase in liver enzyme levels (n = 5), and gastrointestinal pain (n = 10, two of whom had to stop treatment). Patients stopped treatment after 300 +/- 186 days due to side effects (3), death (4), or the patient's (5) or physician's decision (33). During the follow-up, one patient suffered a relapse with peripheral lymph nodes. A daily dose of 30 mg/kg of clarithromycin in the treatment of M avium infections appears to be effective and safe. Concomitant drug therapy should be assessed for its ability to prevent relapse.

Middle lobe syndrome: a clinicopathological study of 21 patients

Middle lobe syndrome (MLS) is an uncommon lung disorder involving the right middle lobe and/or lingula and is characterized by a spectrum of clinical and pathological lesions ranging from recurrent atelectasis or pneumonias to bronchiectasis. Despite several series reporting the clinical features of MLS, histopathological descriptions are rare. We reviewed the clinical characteristics and pathological findings in 21 patients with MLS who underwent surgical resections. Six male and 15 female patients between the ages of 5 and 80 years (mean, 47 years) were studied. All patients were symptomatic and complained of chronic cough (8), hemoptysis (6), chest pain (4), dyspnea (3), or fever (2). The right middle lobe was involved in 11 patients, the lingula in four patients, and both right middle lobe and lingula in six patients. Chest radiographs, bronchograms, and/or computed tomography scans were available for review in 19 patients and showed consolidation (8), bronchiectasis (9), patchy infiltrates (5), and atelectasis (4) in various combinations. Pathological findings included bronchiectasis in 10 patients, chronic bronchitis/bronchiolitis with lymphoid hyperplasia in seven, patchy organizing pneumonia in six, atelectasis in five, granulomatous inflammation in five, and abscess formation in four. Three patients with granulomatous inflammation had associated atypical mycobacterial infection. Broncholithiasis was confirmed by pathological examination in one patient. No pathological cause for bronchial obstruction was identified in the remaining 20 patients, although one was thought to have had broncholithiasis on the basis of preoperative bronchoscopy. The presence of bronchiectasis, bronchitis or bronchiolitis, organizing pneumonia, or atelectasis in specimens from the right middle lobe or of lingula in the absence of an identifiable cause of bronchial obstruction should suggest a diagnosis of MLS.

Controlled trial of antimycobacterial therapy in Crohn's disease. Clofazimine versus placebo

In order to study the effect of clofazimine, a powerful antimycobacterial and antiinflammatory agent, 49 patients with active Crohn's disease were randomized to either corticosteroids plus clofazimine 100 mg daily (N = 25) or to steroids and matching placebo (N = 24). A total of 28 patients (58%) went into disease remission (clofazimine 16, placebo 12; P = NS) with a fall in disease activity score from 10.5 +/- 4.4 to 3.3 +/- 3.5. Patients were treated for a further eight months with clofazimine or placebo and 18 of 28 maintained their remission and completed the study (clofazimine 12, placebo 6; P = NS). Side effects were minor and consisted of skin rash and increased pigmentation. Clofazimine as a solitary antimycobacterial agent appears ineffective in inducing remission in Crohn's disease but may have a role in either disease maintenance or combination chemotherapy.

Infection with Mycobacterium avium complex in patients without predisposing conditions

Pulmonary disease caused by Mycobacterium avium complex usually occurs in patients with chronic lung disease or deficient cellular immunity, and its prevalence is increasing. We describe 21 patients (mean age, 66 years) with such infection without the usual predisposing factors, representing 18 percent of the 119 patients surveyed. Seventeen women and 4 men were given a diagnosis of M. avium complex from 1978 to 1987, with a stable incidence over the decade, on the basis of pulmonary symptoms, abnormalities on chest films, positive cultures, and in 14, biopsy evidence of invasive disease. Most of the patients (86 percent) presented with persistent cough and purulent sputum, usually without fever or weight loss. The cough was present for a mean of 25 weeks before the correct diagnosis was made. Radiographic patterns of slowly progressive nodular opacities predominated (71 percent); only five patients had cavitary disease at presentation. All patients responded initially to antimycobacterial therapy, but eight eventually relapsed when it was stopped. Four patients died of progressive pulmonary infection caused by M. avium complex. The extent of the initial pulmonary involvement was greater in patients with progressive disease than in those whose condition improved. We conclude that pulmonary disease caused by the M. avium complex can affect persons without predisposing conditions, particularly elderly women, and that recognition of this disease is often delayed because of its indolent nature.

Crohn's disease and the mycobacterioses: a review and comparison of two disease entities

Crohn's disease is a chronic granulomatous ileocolitis, of unknown etiology, which generally affects the patient during the prime of life. Medical treatment is supportive at best, and patients afflicted with this disorder generally live with chronic pain, in and out of hospitals, throughout their lives. The disease bears the name of the investigator who convincingly distinguished this disease from intestinal tuberculosis in 1932. This distinction was not universally accepted, and the notion of a mycobacterial etiology has never been fully dismissed. Nevertheless, it was 46 years after the distinction of Crohn's disease and intestinal tuberculosis before research attempting to reassociate mycobacteria and Crohn's disease was published. Recently, there has been a surge of interest in the possible association of mycobacteria and Crohn's disease due largely to the isolation of genetically identical pathogenic Mycobacterium paratuberculosis from several patients with Crohn's disease in the United States, the Netherlands, Australia, and France. These pathogenic organisms have been isolated from only a few patients, and direct evidence for their involvement in the disease process is not clear; however, M. paratuberculosis is an obligate intracellular organism and strict pathogen, which strongly suggests some etiologic role. Immunologic evidence of a mycobacterial etiology, as assessed by humoral immune determinations, has been conflicting, but evaluation of the more relevant cellular immunity has not been performed. Data from histochemical searches for mycobacteria in Crohn's disease tissues have been equally conflicting, with acid-fast bacilli detected in 0 to 35% of patients. Animal model studies have demonstrated the pathogenic potential of isolates as well as elucidated the complexity of mycobacterial-intestinal interactions. Treatment of Crohn's disease patients with antimycobacterial agent has not been fully assessed, although case reports suggest efficacy. The similarities in the pathology, epidemiology, and chemotherapy of Crohn's disease and the mycobacterioses are discussed. The issue is fraught with controversy, and the data generated on the association of mycobacteria and Crohn's disease are in their infantile stages so that a general conclusion on the legitimacy of this association cannot be made. While no firm evidence clearly implicates mycobacteria as an etiologic agent of Crohn's disease, the notion is supported by suggestive and circumstantial evidence and a remarkable similarity of Crohn's disease to known mycobacterial diseases.