Intrathoracic nontuberculous mycobacterial infections in otherwise healthy children

Successful management of Mycobacterium abscessus pneumonia in a 53-day-old immunocompetent infant

Pulmonary infection due to Mycobacterium abscessus complex (MABC) usually occurs in children with underlying risk factors including cystic fibrosis (CF), chronic lung disease, and immunocompromised status, but rarely in immunocompetent children without underlying lung disease, especially in infants. We present a case of MABC pulmonary disease (MABC-PD) in an otherwise healthy 53-day-old male infant with one week of cough and respiratory distress. Computed tomography showed multiple masses across both lungs. Isolated mycobacteria from his bronchoalveolar lavage fluid were identified as MABC. We describe our complete evaluation, including immunodeficiency evaluation incorporating whole exome sequencing and our therapeutic process given complicated susceptibility pattern of the M. abscessus isolate, and review literature for MABC-PD in immunocompetent children. The infant was successfully treated through prolonged treatment with parenteral Amikacin, Cefoxitin, Linezolid, and Clarithromycin, combined with inhaled Amikacin.

Nontuberculous Mycobacterial Infections in Pediatric Solid Organ Transplant and Hematopoietic Cell Transplant Recipients

The diagnosis of nontuberculous mycobacterial infections is challenging in pediatric solid organ transplant and hematopoietic cell transplant recipients due to the absence of specific clinical manifestations, limitations of sampling, prolonged times for culture and identification, and difficulty discerning colonization from clinical disease. Treatment is dependent on the nontuberculous mycobacterial species, disease type, and pattern of drug resistance. Treatment of nontuberculous mycobacterial infections involves prolonged durations of therapy using multiple medications, which are limited by toxicities and drug-drug interactions.

International Pediatric Otolaryngology Group: Consensus guidelines on the diagnosis and management of non-tuberculous mycobacterial cervicofacial lymphadenitis

INTRODUCTION

Non-tuberculous mycobacterial (NTM) infection commonly manifests as subacute or chronic cervicofacial lymphadenitis in immunocompetent children. The optimal management of this pathology remains controversial.

OBJECTIVES

This international consensus guideline aims to understand the practice patterns for NTM cervicofacial lymphadenitis and to address the primary diagnostic and management challenges.

METHODS

A modified three-iterative Delphi method was used to establish expert recommendations on the diagnostic considerations, expectant or medical management, and operative considerations. The recommendations herein are derived from current expert consensus and critical review of the literature.

SETTING

Multinational, multi-institutional, tertiary pediatric hospitals.

RESULTS

Consensus recommendations include diagnostic work-up, goals of treatment and management options including surgery, prolonged antibiotic therapy and observation.

CONCLUSION

The recommendations formulated in this International Pediatric Otolaryngology Group (IPOG) consensus statement on the diagnosis and management of patients with NTM lymphadenitis are aimed at improving patient care and promoting future hypothesis generation.

Mycobacterium abscessus Pneumonia in an Immunonormal Infant

A 2-month-old male with failure to thrive and respiratory symptoms was found to have bilateral pneumonia secondary to Mycobacterium abscessus . M. abscessus pulmonary infections have mainly been noted in immunocompromised children; prior reports presented similarly, though our patient is unique given the young age of presentation and lack of diagnosed immunodeficiency or underlying disease.

Extensive Mycobacterium abscessus Pneumonia in an Immunocompetent Infant with No Underlying Lung Pathology

Pulmonary infection due to Mycobacterium abscessus occurs in patients with cystic fibrosis, but rarely in immunocompetent children without underlying lung pathology. Treatment is complicated by frequent resistance to many antibiotics. We present a case report of a 4-month-old female infant with 2 months of cough, difficulty feeding, and failure to thrive, with extensive culture-confirmed M. abscessus pulmonary infection without identified immunodeficiency or underlying lung pathology following multidisciplinary evaluation. We describe our complete evaluation including immunodeficiency evaluation incorporating whole-exome sequencing, describe our antibiotic selection and treatment duration given complicated susceptibility pattern of the M. abscessus isolate, and review literature for nontuberculous mycobacterial pulmonary disease in immunocompetent children. A complete multidisciplinary evaluation for underlying lung disease and primary and acquired immunodeficiency should be undertaken in pediatric patients with M. abscessus pneumonia. Confirming macrolide susceptibility through erm(41) gene evaluation is clinically important for isolates with complicated susceptibility pattern.

Successful management of Mycobacterium abscessus complex lung disease in an otherwise healthy infant

Mycobacterium abscessus complex (MABC) is an uncommon but increasingly important cause of invasive pulmonary disease, a condition associated with diagnostic and management challenges. MABC has mainly been reported in children with certain medical conditions, such as preexisting structural lung disorders and immunocompromised status. In this article, we describe a rare case of MABC pulmonary disease in an otherwise healthy infant. A 4-month-old female presented with cough and fever for 4 days. Computed tomography showed multiple masses and small nodules across both lungs. Isolated mycobacteria from her bronchoalveolar lavage fluid and gastric aspirate were identified as MABC by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and M. abscessus subsp. massiliense was ultimately identified by DNA sequence analysis. Prolonged treatment with a combination of azithromycin, cefoxitin, and moxifloxacin achieved a successful treatment outcome.

Endobronchial Non-Tuberculosis Mycobacterium Infection Presenting in a Healthy Child

OBJECTIVES

To describe a safe and effective treatment for endobronchial Mycobacterium avium complex.

METHODS

Case report and literature review.

RESULTS

We present a case of endobronchial M. avium complex in a healthy child treated with serial carbon-dioxide laser excisions and antibiotic triple therapy using azithromycin, rifampin, and ethambutol. No current guideline for the treatment of these lesions in the pediatric population exists.

CONCLUSIONS

In patients with airway impingement, serial endoscopic surgical resection combined with antibiotics can provide safe and effective management.

Pulmonary Mycobacterium Avium-Intracellulare Complex Infection in an Infant: A Silent and Coincidental Finding

An 11-month-old healthy infant girl was noted to have left lower lobe (LLL) opacities on chest X-ray (CXR) after developing desaturations during an elective cochlear implant surgery. Repeat CXR 10 days later revealed hyperexpansion of the left lung and persistent LLL opacity. Chest computerized tomography revealed enlarged mediastinal lymph nodes, left mainstem bronchial obstruction, and nodular opacities. Bronchoscopic biopsy of the endobronchial tissue revealed multiple necrotizing granulomas and grew Mycobacterium avium-intracellulare, Streptococcus viridans, and Actinomyces odontolyticus. This case illustrates the potential for significant mediastinal lymphadenopathy, and endobronchial and parenchymal lesions caused by nontuberculous mycobacteria, which can present insidiously and without respiratory symptoms in otherwise healthy infants, despite advanced pulmonary disease.

Human health risks for Legionella and Mycobacterium avium complex (MAC) from potable and non-potable uses of roof-harvested rainwater

A quantitative microbial risk assessment (QMRA) of opportunistic pathogens Legionella pneumophila (LP) and Mycobacterium avium complex (MAC) was undertaken for various uses of roof-harvested rainwater (RHRW) reported in Queensland, Australia to identify appropriate usages and guide risk management practices. Risks from inhalation of aerosols due to showering, swimming in pools topped up with RHRW, use of a garden hose, car washing, and toilet flushing with RHRW were considered for LP while both ingestion (drinking, produce consumption, and accidental ingestion from various activities) and inhalation risks were considered for MAC. The drinking water route of exposure presented the greatest risks due to cervical lymphadenitis and disseminated infection health endpoints for children and immune-compromised populations, respectively. It is therefore not recommended that these populations consume untreated rainwater. LP risks were up to 6 orders of magnitude higher than MAC risks for the inhalation route of exposure for all scenarios. Both inhalation and ingestion QMRA simulations support that while drinking, showering, and garden hosing with RHRW may present the highest risks, car washing and clothes washing could constitute appropriate uses of RHRW for all populations, and toilet flushing and consumption of lettuce irrigation with RHRW would be appropriate for non- immune-compromised populations.

Mycobacterium avium Complex Disease

Despite the ubiqitous nature of Mycobacterium avium complex (MAC) organisms in the environment, relatively few of those who are infected develop disease. Thus, some degree of susceptibility due to either underlying lung disease or immunosuppression is required. The frequency of pulmonary MAC disease is increasing in many areas, and the exact reasons are unknown. Isolation of MAC from a respiratory specimen does not necessarily mean that treatment is required, as the decision to treatment requires the synthesis of clinical, radiographic, and microbiologic information as well as a weighing of the risks and benefits for the individual patient. Successful treatment requires a multipronged approach that includes antibiotics, aggressive pulmonary hygiene, and sometimes resection of the diseased lung. A combination of azithromycin, rifampin, and ethambutol administered three times weekly is recommend for nodular bronchiectatic disease, whereas the same regimen may be used for cavitary disease but administered daily and often with inclusion of a parenteral aminoglycoside. Disseminated MAC (DMAC) is almost exclusively seen in patients with late-stage AIDS and can be treated with a macrolide in combination with ethambutol, with or without rifabutin: the most important intervention in this setting is to gain HIV control with the use of potent antiretroviral therapy. Treatment outcomes for many patients with MAC disease remain suboptimal, so new drugs and treatment regimens are greatly needed. Given the high rate of reinfection after cure, one of the greatest needs is a better understanding of where infection occurs and how this can be prevented.

Host susceptibility to non-tuberculous mycobacterial infections

Non-tuberculous mycobacteria cause a broad range of clinical disorders, from cutaneous infections, such as cervical or intrathoracic lymphadenitis in children, to disseminated infections at all ages. Recognition of the underlying immune defect is crucial for rational treatment, preventive care, family screening, and, in some cases, transplantation. So far, at least seven autosomal mutations (in IL12B, IL12RB1, ISG15, IFNGR1, IFNGR2, STAT1, and IRF8) and two X-linked mutations (in IKBKG and CYBB), mostly presenting in childhood, have been reported to confer susceptibility to disseminated non-tuberculous mycobacterial infection. GATA2 deficiency and anti-interferon γ autoantibodies also give rise to disseminated infection, typically in late childhood or adulthood. Furthermore, isolated pulmonary non-tuberculous mycobacterial infection has been increasing in prevalence in people without recognised immune dysfunction. In this Review, we discuss how to detect and differentiate host susceptibility factors underlying localised and systemic non-tuberculous mycobacterial infections.

Endobronchial lesions caused by nontuberculous mycobacteria in apparently healthy pediatric patients

Pulmonary disease caused by nontuberculous mycobacteria in healthy children is rare, and its pathogenesis is unknown in most cases and standardized treatment is lacking. Here, we report various endobronchial manifestations in 5 patients including hitherto undescribed diffuse tracheobronchial granulomas in 2 patients. Bronchoscopic debulking was performed in all patients and tuberculostatic treatment in 4. All patients including 1 without tuberculostatic treatment showed remission.

Diversity of Mycobacterium avium subsp. hominissuis mycobacteria causing lymphadenitis, France

The knowledge of Mycobacterium avium complex (MAC) genotypes responsible for lymphadenitis is limited. We retrospectively characterized all of the MAC isolates made in our laboratory in the last 18 years by sequence-based identification and genotyping, and compared the clinical and laboratory data for lymphadenitis-associated and non-lymphadenitis-associated MAC isolates. Of 67 MAC-infected patients, 25 lymphadenitis patients were significantly younger than 42 non-lymphadenitis patients, while the male/female ratio did not significantly differ between the two groups. Cervical topography found in 76.5% of lymphadenitis patients was significantly more frequent in non-immunocompromised patients (p=0.04). M. avium subsp. hominissuis was identified in 53 patients (24 lymphadenitis, 29 non-lymphadenitis), M. colombiense in six patients (five non-lymphadenitis, one lymphadenitis), M. intracellulare in four non-lymphadenitis patients, and M. chimaera in three non-lymphadenitis patients, while negative controls remained negative. M. hominissuis was significantly associated with lymphadenitis (p=0.03). M. hominissuis isolates yielded 15 genotypes in 29 non-lymphadenitis isolates (molecular diversity, 0.622) versus 11 genotypes in 24 lymphadenitis isolates (molecular diversity, 0.578), demonstrating a non-significant lower diversity of M. hominissuis isolates cultured from lymphadenitis. The genotypes did not correlate with the clinical features. These data suggest the presence of several environmental reservoirs for M. hominissuis causing lymphadenitis in France.

Pulmonary nontuberculous mycobacterial disease: new insights into risk factors for susceptibility, epidemiology, and approaches to management in immunocompetent and immunocompromised patients

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and cause a wide range of diseases in humans. Pulmonary involvement, the most common disease manifestation of NTM infection, is being increasingly encountered in clinical settings. In addition, specific phenotypic and genetic characteristics of persons predisposed to contract pulmonary NTM disease are now beginning to be recognized. Prior to treatment, patients should meet clinical and microbiologic criteria for NTM disease. Treatment involves prolonged courses of antibiotics in various combination regimens that are often discontinued because of serious side effects. In some cases, complete cure of pulmonary disease is difficult to achieve. Rather, clinical improvement may be a more feasible goal. Surgical treatment is warranted for select patients.

Blurring the lines in interferon {gamma} receptor deficiency: an infant with near-fatal airway disease

Deficiencies of the interferon γ (IFN-γ) pathway have become a well-recognized cause of nontuberculous mycobacterial infection. We report here a case of autosomal dominant IFN-γ receptor 1 (IFN-γ-R1) deficiency presenting at the unusually young age of 16 months with a severe clinical course. Mycobacterium avium complex was cultured from bronchial washings of a child who presented with primary endobronchial disease after a 4-month history of rhinorrhea, wheeze, and acute lobar consolidation. A maternal history of multifocal Mycobacterium kansasii osteomyelitis and cutaneous M avium complex led to genetic confirmation of IFN-γ-R1 818del4 deletion (a 4 base pair deletion at nucleotide position 818) in both family members. This case demonstrates the link between mycobacterial disease and IFN-γ pathway deficiency, the diagnosis of which facilitates more accurate therapy and genetic counseling. The case also raises questions about the reported distinct presentation, treatment, and prognosis of autosomal dominant and recessive IFN-γ-R1 phenotypes.