Nontuberculous mycobacterial disease in childhood - update on diagnostic approaches and treatment

Mediastinal Nontuberculous Mycobacterial Infection in Children: A Multidisciplinary Approach

BACKGROUND

Mediastinal infections due to nontuberculous mycobacteria remain an exceedingly rare entity. Most cases in the published literature do not include pediatric patients. Due to their clinical infrequency, poor response to antimicrobial therapy and often precarious anatomical location, the optimal management of these lesions can be challenging.

METHODS

Retrospective medical record review of 4 pediatric cases of mediastinal nontuberculous mycobacteria infection was undertaken. Each child presented with nonspecific respiratory symptoms, including significant acute airway obstruction and required a range of investigations to confirm the diagnosis. Nonresponsiveness to conservative measures and antimycobacterial therapy ultimately resulted in surgical intervention to obtain clinical improvement.

RESULTS

All 4 children had extensive evaluation and multidisciplinary involvement in otolaryngology, respiratory medicine, pediatric surgery, infectious diseases and cardiothoracic surgery. They all eventually had their disease debulked via thoracotomy in addition to prolonged antimycobacterial therapy, with successful clinical outcomes.

CONCLUSIONS

Mediastinal nontuberculous mycobacteria infections in the pediatric population are rare and diagnostically challenging. A high clinical suspicion should be maintained, and multidisciplinary input sought. Targeted surgery with adjuvant medical therapy can reduce disease burden with minimal long-term morbidity.

Prevalence and Characteristics of Non-tuberculous Mycobacteria (NTM) Infection in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: a Systematic Review and Meta-analysis

PURPOSE

Non-tuberculous mycobacteria (NTM) infections in hematopoietic stem cell transplantation (HSCT) recipients represent a diagnostic and therapeutic challenge. Here, we aimed to review and analyze current literature on incidence, clinical presentation, and outcome of NTM infection after allogeneic HSCT.

METHODS

We performed a systematic review and meta-analysis of available literature regarding NTM infection in children and adults receiving allogeneic HSCT.

RESULTS

We identified 56 articles eligible for the analysis. Among 15 studies, describing 15,798 allogeneic HSCT, we estimated a prevalence of 1.26% (95% CI 0.72, 1.93) of NTM after transplant. Analysis of 175 patients with NTM infection showed a median time of diagnosis of 318 days after HSCT, an increased prevalence in adults (82.9%), and a most frequent pulmonary involvement (44%). Comparison between children and adults revealed an earlier post-transplant disease onset (median 130 days vs 287 days) and most frequent non-pulmonary presentation in children. A vast heterogeneity of therapeutic approach reflected the lack of universal recommendations regarding drug combination and duration of therapy. Overall, NTM-related mortality accounted for 33% in this systematic review.

CONCLUSION

Although rare, NTM infections can complicate post-transplant course with a high mortality rate in children and adults. The lack of prospective studies and guidelines prevents identification of risk factors and therapeutic recommendations.

Challenging diagnosis of Mycolicibacterium cosmeticum/canariasense infection: A case report and literature review

We present the case of an immunocompromised child with Mycolicibacterium cosmeticum/ canariasense infection. Our case highlights the difficulty in adequate speciation. Most isolates described in the literature were identified using 16 s-rRNA PCR, which if performed on our sample would at best be inconclusive. Misidentifications could have a real impact on the body of evidence collected on these isolates thus far.

Long-Term Esthetic Outcome of Different Treatment Modalities for Nontuberculous Mycobacterial Cervicofacial Lymphadenitis

BACKGROUND

Nontuberculous mycobacterial (NTM) cervicofacial lymphadenitis is a rare infection which almost exclusively occurs in children, most commonly children 0-5 years old. It can leave scars in highly visible areas. The present study aimed to evaluate the long-term esthetic outcome of different treatment modalities for NTM cervicofacial lymphadenitis.

METHODS

This retrospective cohort study included 92 participants with a history of bacteriologically proven NTM cervicofacial lymphadenitis. All patients were diagnosed at least 10 years prior and were aged >12 years upon enrollment. Based on standardized photographs, the scars were assessed by subjects with the Patient Scar Assessment Scale, and by five independent observers with the revised and weighted Observer Scar Assessment Scale.

RESULTS

The mean age at initial presentation was 3,9 years and the mean follow-up time was 15.24 years. Initial treatments included surgical treatment (n = 53), antibiotic treatment (n = 29) and watchful waiting (n = 10). Subsequent surgery was performed in two patients, due to a recurrence after initial surgical treatment, and in 10 patients initially treated with antibiotic treatment or watchful waiting. Esthetic outcomes were statistically significantly better with initial surgery, compared to initial non-surgical treatment, based on patient scores of scar thickness, and based on observer scores of scar thickness, surface appearance, general appearance and the revised and weighted sum score of all assessment items.

CONCLUSIONS

The long-term esthetic outcome of surgical treatment was superior to non-surgical treatment. These findings could facilitate the process of shared decision making.

LEVEL OF EVIDENCE

Level III.

Non-Tuberculous Mycobacterial Cervicofacial Lymphadenitis in Children-10-Year Experience in a Tertiary Pediatric Center

BACKGROUND

Lymphadenitis is the most common manifestation of non-tuberculous mycobacteria (NTM) infection in children. We describe the epidemiology and clinical characteristics of NTM lymphadenitis, determine diagnostic yield from tissue sampling, and review management and outcomes.

METHODS

This was a 10-year retrospective review of children aged 0-16 years diagnosed with NTM cervicofacial lymphadenitis who were seen in a pediatric infectious disease clinic in a tertiary public hospital. Data relating to patient demographics, clinical features, surgical and antimicrobial treatment, complications, and outcomes were retrieved from patients' electronic medical records and analyzed.

RESULTS

There were 48 episodes of NTM cervicofacial lymphadenitis in 45 children (17 males and 28 females). Of these episodes, 43.7% manifested as a unilateral single node, mostly parotid (39.6%) and submandibular (29.2%). All patients underwent diagnostic fine-needle aspiration or surgery. Surgical excision more frequently yielded positive histological findings (P = .016). NTM was identified in 22/48 episodes (45.8%) via culture or molecular sequencing. Mycobacterium abscessus was most commonly found (47.8%). Thirty-eight children (79.2%) received antibiotics. Outcomes in 43 episodes revealed full resolution in 69.8%, while 25.6% had de novo disease and 4.6% experienced recurrence at the same site. Overlying skin changes and multiple or bilateral nodal diseases were significantly associated with de novo disease or recurrence (P = .034 and .084, respectively). Complications occurred in 11/70 (15.7%) procedures. Antibiotic-associated adverse effects occurred in 14/38 (36.8%) episodes.

CONCLUSIONS

NTM lymphadenitis remains a challenging condition. More aggressive management with surgical excision and antibiotics is recommended for those with overlying skin changes and extensive nodal disease.

Non-tuberculous Mycobacterial Infection of the Retropharyngeal Space

We report a case of Mycobacterium avium complex infection of the retropharyngeal space in a 20-month-old girl. We also summarize the published literature on the pathogenesis and management of nontuberculous mycobacterial infections of the retropharynx.

Surgical management of parotid non-tuberculous mycobacteria lymphadenitis in children: A pediatric tertiary-care hospital's experience

OBJECTIVE

Non-tuberculous mycobacteria (NTM) represents an important etiology of cervicofacial lymphadenitis (CFL) and skin/soft tissue infections in children. It can also affect the salivary glands, including the parotid gland, which is unique due to the presence of intra-salivary lymph nodes. There are no established guidelines for treatment of NTM CFL. NTM lymphadenitis was historically surgically treated; recently the literature supports initial medical treatment. Treatment decisions have been dependent on the extent of disease, preference of providers, and risk of surgical complications. The goal is to report our experience in surgical outcomes of NTM CFL with involvement of the parotid gland after pre-operative medical management.

METHODS

A retrospective case series of patients with NTM affecting the parotid gland at a tertiary care pediatric hospital between 2004 and 2020.

RESULTS

Seventy-two patients were referred for surgical evaluation of possible parotid NTM. Thirty-three patients underwent surgical excision. Fifteen patients were identified with presumed NTM infection involving the parotid gland. There were twelve females and three males with a mean age of 2.0 years (SD 1.55; range 1-6 days) at the time of surgery. All underwent surgical excision with parotidectomy. The most common pre-operative antimycobacterial therapy used was a combination of clarithromycin and rifampin. All 15 patients had pathological findings consistent with NTM infection (granulomatous lymphadenitis). Forty percent (n = 6) of patients had positive stains with acid-fast bacilli (AFB), with Mycobacterium avium as the most common species (n = 5). The majority of patients, 86.67% (n = 13), had complete resolution of infection after surgery. Clarithromycin and rifampin were the most common post-operative antimycobacterial treatment (mean 81.5 days, SD 110.14, range 2-411 days). The most common complication experienced was acute (<3 months) lower facial nerve paresis (40%, n = 6), but no patient had permanent facial paralysis.

CONCLUSION AND RELEVANCE

Parotidectomy is a safe and efficacious treatment in patients with NTM CFL affecting the parotid gland after incomplete resolution with antimycobacterial therapy. Further investigation to optimize duration of antimycobacterial treatment is necessary. We highlight the experience of a high-volume tertiary care pediatric hospital with surgical management of this disease.

Management of Infectious Lymphadenitis in Children

Lymphadenopathy is an irregularity in the size and texture of the lymph nodes, which is quite common in childhood. When the enlargement of lymph nodes is caused by inflammatory and infectious processes, it is called lymphadenitis. The main objective of this manuscript is to summarize the common infectious etiologies and presentations of lymphadenitis in children providing a management guide for clinical practice. PubMed was used to search for all of the studies published up to April 2021 using keywords such as "lymphadenitis" and "children". Literature analysis showed that the differential diagnosis for lymphadenitis in pediatrics is broad. Although lymph node enlargement in children is usually benign and self-limited, it is important to exclude malignant etiology. In most cases, history and physical examination allow to identify the correct diagnosis and start a proper treatment with a prompt resolution of the lymphadenopathy. However, particularly in the case of persistent lymphadenitis, determining the cause of lymph node enlargement may be difficult, and the exact etiology may not be identified despite extensive investigations. Further studies should develop and validate an algorithm to assist pediatricians in the diagnosis and timely treatment of lymphadenitis, suggesting situations in which a watchful waiting may be considered a safe approach, those in which empiric antibiotic therapy should be administered, and those requiring a timely diagnostic work-up.

Interferon-Gamma Release Assays Differentiate between Mycobacterium avium Complex and Tuberculous Lymphadenitis in Children

OBJECTIVES

To assess the performance of interferon-gamma release assays (IGRAs) in the differential diagnosis between Mycobacterium avium complex (MAC) and tuberculosis (TB) in children affected with subacute/chronic submandibular/cervical lymphadenitis.

STUDY DESIGN

Multicenter observational study comparing children with microbiologically confirmed MAC lymphadenitis from the European NontuberculouS MycoBacterial Lymphadenitis in childrEn study with children with TB lymphadenitis from the Spanish Network for the Study of Pediatric TB database.

RESULTS

Overall, 78 patients with MAC and 34 with TB lymphadenitis were included. Among MAC cases, 44 out of 74 (59.5%) had positive tuberculin skin test (TST) results at the 5-mm cut-off, compared with 32 out of 33 (97%) TB cases (P < .001); at the 10-mm cut-off TST results were positive in 23 out of 74 (31.1%) vs 26 out of 31 (83.9%), respectively (P < .001). IGRA results were positive in only 1 out of 32 (3.1%) patients with MAC who had undergone IGRA testing, compared with 21 out of 23 (91.3%) TB cases (P < .001). Agreement between TST and IGRA results was poor in MAC (23.3%; κ = 0.017), but good in TB cases (95.6%; κ = 0.646). IGRAs had a specificity of 96.9% (95% CI 84.3%-99.8%), positive predictive value of 95.4% (95% CI 78.2%-99.8%), and negative predictive value of 93.9% (95% CI 80.4%-98.9%) for TB lymphadenitis.

CONCLUSIONS

In contrast to TST, IGRAs have high specificity, negative predictive value, and positive predictive value for TB lymphadenitis in children with subacute/chronic lymphadenopathy, and consequently can help to discriminate between TB and MAC disease. Therefore, IGRAs are useful tools in the diagnostic work-up of children with lymphadenopathy, particularly when culture and polymerase chain reaction results are negative.

Clinical Performance of Mycobacterial Immunohistochemistry in Anatomic Pathology Specimens

OBJECTIVES

Diagnosis of mycobacterial infections poses significant challenges in anatomic pathology. We recently described the use of antimycobacteria immunohistochemistry (IHC) as a sensitive, efficient diagnostic tool and now report the clinical performance of this assay among general, noninfectious disease pathology-trained anatomic pathologists.

METHODS

Over a 2-year period, all cases were retrospectively identified in which mycobacterial IHC was performed during routine diagnostic workup.

RESULTS

From October 2017 to September 2019, mycobacterial IHC was evaluated for 267 cases, resulting in 58 (22%) positive stains. Compared with culture and molecular results, the sensitivity and specificity of IHC were 52% and 80%, respectively. IHC performed significantly better than acid-fast bacilli (AFB) staining (Ziehl-Neelsen) (P < .0001; sensitivity 21%, specificity 92%) but similarly to modified AFB staining (mAFB; Fite-Faraco) (P = .9; sensitivity 61%, specificity 84%). In cases with discordant IHC and mAFB staining, there were no differences in rates of culture or polymerase chain reaction-confirmed positivity.

CONCLUSIONS

Mycobacterial IHC was well adopted with superior clinical performance to AFB and comparable performance to mAFB. These results support the use of IHC as an adjunctive tool in the diagnosis of mycobacterial infections and suggests its potential role as a rapid screening test for molecular testing.

Non-Tuberculous Mycobacterial Diseases in Children

Non-tuberculous mycobacteria (NTMs) are ubiquitous and opportunistic emerging bacteria with the potential to colonize and eventually infect either immunocompromised or immunocompetent individuals. In the last three decades, the prevalence of disease caused by NTMs has increased in several countries. The increased prevalence of NTM infection can be explained by an ageing population with rising comorbidities, HIV infection, the common use of immunosuppressive drugs, and improved diagnostic methods. The aim of this review is to demonstrate the clinical relevance of NTMs in children, describing their features and manifestations, diagnostic tools, and therapeutic approaches. We collected data from the literature about NTM infections in young patients over the past five years (2014–2019) using the keywords “non-tuberculous”, “mycobacteria”, “paediatric”, “NTM”, “cystic fibrosis”, and “children”. Recent literature points out that NTMs are ubiquitous, with several species including both those that are pathogens for humans and those that are not. This means that, if a mycobacterium is isolated from a patient’s specimen, we have to distinguish between a simple colonization and an NTM-related disease. The start of treatment depends on many factors that are necessary to consider, such as clinical and imaging features, patient comorbidity and immunocompetence, drug adverse effects, and compliance with a very long therapy that can last many months. Due to the increasing prevalence and clinical relevance of NTMs, guidelines for their optimal management, especially in the presence of chronic underlying disease, are urgently needed.

Submandibular lymphadenitis due to Mycobacterium malmoense: first reported case from Greece

An 8-year-old girl with subacute submandibular lymphadenitis and no other complaints is described. After failure of parenteral antistaphylococcal therapy, she underwent incision and drainage of the involved lymph node. The responsible pathogen was identified as Mycobacterium malmoense by GenoType CM assay and sequencing of the 16S ribosomalRNA (rRNA) gene. The patient remains healthy, 11 months after surgery, even though it took approximately 4 months for the surgical incision to heal completely. While M. malmoense is a relatively common cause of non-tuberculous mycobacteria (NTM) lymphadenitis in Northern Europe, this is the first reported case from Greece. We conclude that in a young child with lymphadenitis without systemic symptoms, the microbiology laboratory should be notified in advance in order to extend the duration of mycobacterial cultures. Application of molecular methods will increase the number of reported cases of rare NTM in the future.

Cluster of Lymphadenitis due to Nontuberculous Mycobacterium in Children and Adolescents 8-15 Years of Age

BACKGROUND

Nontuberculous mycobacteria (NTM) lymphadenitis is an under-recognized entity, and data of the true burden in children are limited. Without a high index of suspicion, diagnosis may be delayed and microbiological detection is challenging. Here, we report a cluster of NTM lymphadenitis experienced in Korean children.

METHODS

Subjects under 19 years of age diagnosed with NTM lymphadenitis during November 2016-April 2017 and April 2018 were included. Electronic medical records were reviewed for clinical, laboratory and pathological findings. Information regarding underlying health conditions and environmental exposure factors was obtained through interview and questionnaires.

RESULTS

A total of ten subjects were diagnosed during 18 months. All subjects were 8-15 years of age, previously healthy, male and had unilateral, nontender, cervicofacial lymphadenitis for more than 3 weeks with no significant systemic symptoms and no response to empirical antibiotics. Lymph nodes involved were submandibular (n = 8), preauricular (n = 6) and submental (n = 1). Five patients had two infected nodes and violaceous discoloration was seen in seven subjects. Biopsy specimens revealed chronic granulomatous inflammation and acid-fast bacteria culture identified Mycobacterium haemophilum in two cases and NTM polymerase chain reaction was positive in two cases. Survey revealed various common exposure sources.

CONCLUSION

NTM lymphadenitis is rare but increasing in detection and it may occur in children and adolescents. Diagnosis requires high index of suspicion and communication between clinicians and the laboratory is essential for identification of NTM.

Increase in Childhood Nontuberculous Mycobacterial Infections After Bacille Calmette-Guérin Coverage Drop: A Nationwide, Population-Based Retrospective Study, Finland, 1995-2016

Background

Epidemiological data on childhood nontuberculous mycobacterial (NTM) disease is scarce and the protective effect of bacille Calmette-Guérin (BCG) vaccination remains debated. In 2006, the BCG policy in Finland changed from universal to selective. We aimed to study the effect of the BCG coverage decrease on the incidence of childhood NTM infections in Finland.

Methods

We conducted a nationwide, population-based, retrospective study of NTM notifications recorded to the National Infectious Diseases Register between 1995 and 2016 and identified native-born children aged 0-4 years infected with NTM. Poisson log-linear model was used to estimate the change in the incidence rate of cohorts born during universal or selective BCG policy between 1995 and 2015.

Results

We identified 97 native-born children aged <5 years infected with NTM (median age, 27 months; female-to-male ratio, 2:1). The most common species was Mycobacterium avium (n = 69 [71%]). The estimated incidence rates of NTM in universal-BCG and selective-BCG cohorts were 0.2 and 3.9 per 100000 person-years, respectively. The incidence rate ratio of selective-BCG cohorts compared to universal-BCG cohorts was 19.03 (95% confidence interval, 8.82-41.07; P < .001).

Conclusions

After infant BCG coverage in Finland decreased, childhood NTM infections increased drastically. As there is no other apparent cause for the increase, this indicates that BCG offers protection against childhood NTM disease. This observation adds to the understanding of childhood NTM epidemiology and might explain why the disease is emerging in some countries.

Surgical treatment of non-tuberculous mycobacterial lymphadenitis in children: Our experience and a narrative review

Non-tuberculous mycobacterial lymphadenitis (NTML) accounts for about 95% of the cases of head-and-neck mycobacterial lymphadenitis, and its prevalence has been increasing in the Western world. The diagnostic work-up can be challenging, and differential diagnoses such as tuberculous and suppurative lymphadenitis need to be considered. It may, therefore, not be diagnosed until the disease is in a late stage, by which time it becomes locally destructive and is characterized by a chronically discharging sinus. The treatment options include a medical approach, a wait-and-see policy, and surgery, with the last being considered the treatment of choice despite the high risk of iatrogenic nerve lesions. The aim of this article is to provide an overview of pediatric, head-and-neck NTML based on the literature and our own experience, with particular emphasis on the impact and limitations of surgery.

Mycobacterium abscessus Smooth and Rough Morphotypes Form Antimicrobial-Tolerant Biofilm Phenotypes but Are Killed by Acetic Acid

Mycobacterium abscessus has emerged as an important pathogen in people with chronic inflammatory lung diseases such as cystic fibrosis, and recent reports suggest that it may be transmissible by fomites. M. abscessus exhibits two major colony morphology variants: a smooth morphotype (Ma^Sm ) and a rough morphotype (Ma^Rg ). Biofilm formation, prolonged intracellular survival, and colony variant diversity can each contribute to the persistence of M. abscessus and other bacterial pathogens in chronic pulmonary diseases. A prevailing paradigm of chronic M. abscessus infection is that Ma^Sm is a noninvasive, biofilm-forming, persistent phenotype and Ma^Rg an invasive phenotype that is unable to form biofilms. We show that Ma^Rg is hyperaggregative and forms biofilm-like aggregates, which, like Ma^Sm biofilm aggregates, are significantly more tolerant than planktonic variants to acidic pHs, hydrogen peroxide (H₂O₂), and treatment with amikacin or azithromycin. We further show that both variants are recalcitrant to antibiotic treatment inside human macrophage-like cells and that Ma^Rg is more refractory than Ma^Sm to azithromycin. Our results indicate that biofilm-like aggregation and protracted intracellular survival may each contribute to the persistence of this problematic pathogen in the face of antimicrobial agents regardless of morphotype. Biofilms of each M. abscessus variant are rapidly killed, however, by acetic acid, which may help to prevent local fomite transmission.