Common presentations of nontuberculous mycobacterial infections

Mycobacterium abscessus pulmonary disease presenting with spontaneous pneumomediastinum and subcutaneous emphysema in childhood acute lymphoblastic leukemia: a case report and literature review

INTRODUCTION

Mycobacterium abscessus is a rapidly growing mycobacterium commonly identified in adults with underlying pulmonary diseases but is rarely observed in children. A better understanding of this pathogen in children is essential.

CASE PRESENTATION

We report the case of a 49-month-old female child without previous underlying pulmonary diseases but with acute lymphoblastic leukemia (ALL). The patient was complicated with pneumonia during chemotherapy, which was primarily characterized by spontaneous pneumomediastinum and subcutaneous emphysema on chest computed tomography (CT). M. abscessus sequences were detected by metagenomic next-generation sequencing in bronchoalveolar lavage fluid. With mechanical ventilation, closed thoracic drainage, and anti-infective therapy for 6 months, the patient's infection was controlled. The patient completed 2.5 years of treatment for ALL, and the drugs were discontinued. The patient currently remains in complete hematologic remission.

DISCUSSION

We reviewed the literature on 33 children with M. abscessus pulmonary disease. These children mostly had underlying immunodeficiency. Chest CT most often showed nodular shadows, consolidation, and bronchiectasis. Spontaneous pneumomediastinum and subcutaneous emphysema were not reported as major manifestations.

CONCLUSION

Spontaneous pneumomediastinum and subcutaneous emphysema were our patient's main characteristics on chest CT, and this study enriches the knowledge regarding possible imaging changes in M. abscessus pulmonary disease in children. This case report reflects good clinical experience in maintaining the balance between chemotherapy and anti-infective therapy in childhood ALL.

Cavitating pulmonary lung lesions with more than one microbiological aetiology

Non-tuberculous mycobacteria (NTM) are one of the predominant microbes observed in immunocompromised patients with structural lung disease. Especially in immunocompromised patients, the treating physician needs to be aware of concurrent lung infections with opportunistic pathogens. In this case report we present a man in his 60s with severe chronic obstructive pulmonary disease (COPD) and bullous emphysema, who was diagnosed with Mycobacterium europaeum but with persistent clinical deterioration despite relevant treatment for NTM. A subsequent bronchoalveolar lavage (BAL) revealed elevated Aspergillus galactomannan antigen which, when seen in relation to imaging-findings of cavitating opacities with aggravating surrounding consolidation, raised suspicion of concurrent subacute invasive aspergillosis. Antifungal treatment was initiated but due to intolerable side effects was discontinued after only a few weeks. This case highlights the importance of concurrent testing for pulmonary aspergillosis in NTM patients and vice versa before treatment initiation and if the disease and symptoms are progressing despite relevant treatment.

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.

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.

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.

Nontubercular Mycobacterial Infection in a Renal Allograft Recipient

A 71-year-old male, a renal allograft recipient, presented to us with a history of fever and right palm swelling. He had a history of fever 7 years back when he was treated with antitubercular treatment (ATT). Three years back, he was diagnosed to have gout and he was started on allopurinol. He developed severe bone marrow toxicity and allopurinol was changed to febuxostat. On admission, routine investigations did not reveal any focus of infection. The fluid aspirate from the palm revealed acid-fast bacilli (AFB). He was started on ATT; however, he did not show significant improvement. Two months later, he developed multiple subcutaneous lesions, and the pus again came positive for AFB. Due to lack of improvement, the aspirate was sent for molecular diagnostic identification. The mycobacteria was identified as Mycobacterium haemophilum. His treatment was changed to rifampicin, clarithromycin, and ciprofloxacin. As he showed slow improvement, his immunosuppression was tapered slowly. At 7 months of therapy, he is clinically better and his lesions are healing. His renal functions stayed stable despite tapering of cyclosporine in a patient who is on rifampicin. This case, the first report of M. haemophilum infection in a kidney transplant recipient in India, illustrates the difficulty in diagnosing nontubercular mycobacterial infection in transplant recipients. It also emphasizes the dilemma in tapering immunosuppressive drugs in disseminated nontubercular mycobacterial infections where there are considerable interactions between ATT and immunosuppressives.

Mycobacterium abscessus Complex Infections in Children: A Review

PURPOSE OF REVIEW

Infections in children with Mycobacterium abscessus complex represent a particular challenge for clinicians. Increasing incidence of these infections worldwide has necessitated focused attention to improve both diagnostic as well as treatment modalities. Published medical literature was reviewed, with emphasis on material published in the past 5 years.

RECENT FINDINGS

Increasing availability of new diagnostic tools, such as matrix-assisted laser desorption ionization-time of flight mass spectrometry and custom PCRs, has provided unique insights into the subspecies within the complex and improved diagnostic certainty. Microbiological review of all recent isolates at the University of Minnesota Medical Center was also conducted, with description of the antimicrobial sensitivity patterns encountered in our center, and compared with those published from other centers in the recent literature. A discussion of conventional antimicrobial treatment regimens, alongside detailed description of the relevant antimicrobials, is derived from recent publications. Antimicrobial therapy, combined with surgical intervention in some cases, remains the mainstay of pediatric care. Ongoing questions remain regarding the transmission mechanics, immunologic vulnerabilities exploited by these organisms in the host, and the optimal antimicrobial regimens necessary to enable a reliable cure. Updated treatment guidelines based on focused clinical studies in children and accounting especially for the immunocompromised children at greatest risk are very much needed.

Pediatric Dental Clinic-Associated Outbreak of Mycobacterium abscessus Infection

BACKGROUND

Mycobacterium abscessus is an uncommon cause of invasive odontogenic infection.

METHODS

M abscessus-associated odontogenic infections occurred in a group of children after they each underwent a pulpotomy. A probable case-child was defined as a child with facial or neck swelling and biopsy-confirmed granulomatous inflammation after a pulpotomy between October 1, 2013, and September 30, 2015. M abscessus was isolated by culture in confirmed case-children. Clinical presentation, management, and outcomes were determined by medical record abstraction.

RESULTS

Among 24 children, 14 (58%) were confirmed case-children. Their median age was 7.3 years (interquartile range, 5.8-8.2 years), and the median time from pulpotomy to symptom onset was 74 days (range, 14-262 days). Clinical diagnoses included cervical lymphadenitis (24 [100%] of 24), mandibular or maxillary osteomyelitis (11 [48%] of 23), and pulmonary nodules (7 [37%] of 19). Each child had ≥1 hospitalization and a median of 2 surgeries (range, 1-6). Of the 24 children, 12 (50%) had surgery alone and 11 (46%) received intravenous (IV) antibiotics. Nineteen of the 24 (79%) children experienced complications, including vascular access malfunction (7 [64%] of 11), high-frequency hearing loss (5 [56%] of 9), permanent tooth loss (11 [48%] of 23), facial nerve palsy (7 [29%] of 24), urticarial rash (3 [25%] of 12), elevated liver enzyme levels (1 [20%] of 5), acute kidney injury (2 [18%] of 11), incision dehiscence/fibrosis (3 [13%] of 24), and neutropenia (1 [9%] of 11).

CONCLUSIONS

M abscessus infection was associated with significant medical morbidity and treatment complications. Unique manifestations included extranodal mandibular or maxillary osteomyelitis and pulmonary nodules. Challenges in the identification of case-children resulted from an extended incubation period and various clinical manifestations. Clinicians should consider the association between M abscessus infection and pulpotomy in children who present with subacute cervical lymphadenitis. The use of treated/sterile water during pulpotomy might prevent further outbreaks.

Elispot Igra With Purified Protein Derivative Stimulation For Diagnosing Nontuberculous Mycobacterial Cervical Lympadenitis

Childhood cervical lymphadenitis caused by nontuberculous mycobacteria is a diagnostic challenge for the clinician. We present a new promising diagnostic method for childhood nontuberculous mycobacterial lymphadenitis. The modified T-SPOT.TB test with purified protein derivative as an additional antigen is noninvasive with estimated sensitivity and specificity of 1.00 and 0.81, respectively.

Boosting Effect of 2-Phenylquinoline Efflux Inhibitors in Combination with Macrolides against Mycobacterium smegmatis and Mycobacterium avium

The identification of efflux inhibitors to be used as adjuvants alongside existing drug regimens could have a tremendous value in the treatment of any mycobacterial infection. Here, we investigated the ability of four 2-(4'-propoxyphenyl)quinoline Staphylococcus aureus NorA efflux inhibitors (1-4) to reduce the efflux activity in Mycobacterium smegmatis and Mycobacterium avium strains. All four compounds were able to inhibit efflux pumps in both mycobacterial species; in particular, O-ethylpiperazinyl derivative 2 showed an efflux inhibitory activity comparable to that of verapamil, the most potent mycobacterial efflux inhibitor reported to date, and was able to significantly reduce the MIC values of macrolides against different M. avium strains. The contribution of the M. avium efflux pumps MAV_1406 and MAV_1695 to clarithromycin resistance was proved because they were found to be overexpressed in two M. avium 104 isogenic strains showing high-level clarithromycin resistance. These results indicated a correlation between increased expression of efflux pumps, increased efflux, macrolide resistance, and reduction of resistance by efflux pump inhibitors such as compound 2. Additionally, compound 2 showed synergistic activity with clarithromycin, at a concentration below the cytotoxicity threshold, in an ex vivo experiment against M. avium 104-infected macrophages. In summary, the 2-(4'-propoxyphenyl)quinoline scaffold is suitable to obtain compounds endowed with good efflux pump inhibitory activity against both S. aureus and nontuberculous mycobacteria.

Non-tuberculous mycobacterial infection in hospitalized children: a case series

Non-tuberculous mycobacteria (NTM) illness is an emerging life-threatening infection, and paediatric features have not been well studied. The objective of our study was to review the NTM isolates of hospitalized paediatric patients identified at our institution and to describe the characteristics of these cases. Our retrospective chart review from 2010 to 2013 identified 45 patients with 46 positive NTM cultures. Fifteen (33%) patients had received haematopoietic cell transplant, 13 (29%) had cystic fibrosis, and six (13%) were previously healthy. Twenty-seven (59%) NTM isolates were Mycobacterium chelonae/abscessus, 14 (30%) were M. avium intracellulare, and four (9%) were M. immunogenum. The majority (65%) of cases were community-acquired, and 20 (43%) patients were treated as infection. This case series identified a predominance of M. chelonae/abscessus, and includes a substantial number of haematopoietic cell transplant patients, which reflects the changing spectrum of NTM disease as molecular diagnostics improve and quaternary care facilities provide for a larger immunocompromised population.

Molecular identification of non-tuberculous mycobacteria isolated from clinical specimens in Zambia

BACKGROUND

The emergence of Acquired Immunodeficiency Syndrome has highlighted the increased incidence and importance of the disease caused by Non-tuberculous Mycobacteria (NTM). While disease due to M. avium-intracellulare complex is apparently common throughout the world, other Non-tuberculous mycobacterial species have been isolated from both immunocompromised and immunocompetent individuals. The increasing number of infections caused by these organisms has made it clinically important to quickly identify mycobacterial species. The diagnosis of a pathogenic versus a non-pathogenic species not only has epidemiological implications but is also relevant to the demands of patient management. Since antibiotic treatment varies according to the species encountered, species identification would reduce the burden of some of these emerging opportunistic pathogens especially in immunocompromised patients and improve their quality of life.

FINDINGS

A total of 91 NTM suspected isolates from four regions of Zambia were included in the study. These isolates were identified using the sequence analysis of the 16S-23S rRNA intergenic transcribed spacer (ITS) region of Mycobacteria. Fifty-four of the 91 (59%) isolates were identified as NTM and these included M. intracellulare (27.8%), M. lentiflavum (16.7%), M. avium (14.8%), M. fortuitum (7.4%), M. gordonae (7.4%), M. kumamotonense (3.7%), M. indicus pranii (3.7%), M. peregrinum (3.7%), M. elephantis (1.85%), M. flavescens (1.85%), M. asiaticum (1.85%), M. bouchedurhonense (1.85%), M. chimaera (1.85%), M. europaeum (1.85%), M. neourum (1.85%), M. nonchromogenicum (1.5%).

CONCLUSION

The study has shown that DNA sequencing of the ITS region may be useful in the preliminary identification of NTM species. All species identified in this study were potentially pathogenic.

Infections caused by non-tuberculous mycobacteria in recipients of hematopoietic stem cell transplantation

Non-tuberculous mycobacteria (NTM) are acid-fast bacteria that are ubiquitous in the environment and can colonize soil, dust particles, water sources, and food supplies. They are divided into rapidly growing mycobacteria such as Mycobacterium fortuitum, Mycobacterium chelonae, and Mycobacterium abscessus as well as slowly growing species such as Mycobacterium avium, Mycobacterium kansasii, and Mycobacterium marinum. About 160 different species, which can cause community acquired and health care-associated infections, have been identified. NTM are becoming increasingly recognized in recipients of hematopoietic stem cell transplantation (HSCT) with incidence rates ranging between 0.4 and 10%. These infections are 50–600 times commoner in transplant recipients than in the general population and the time of onset ranges from day 31 to day 1055 post-transplant. They have been reported following various forms of HSCT. Several risk factors predispose to NTM infections in recipients of stem cell transplantation and these are related to the underlying medical condition and its treatment, the pre-transplant conditioning therapies as well as the transplant procedure and its complications. Clinically, NTM may present with: unexplained fever, lymphadenopathy, osteomyelitis, soft tissue and skin infections, central venous catheter infections, bacteremia, lung, and gastrointestinal tract involvement. However, disseminated infections are commonly encountered in severely immunocompromised individuals and bloodstream infections are almost always associated with catheter-related infections. It is usually difficult to differentiate colonization from true infection, thus, the threshold for starting therapy remains undetermined. Respiratory specimens such as sputum, pleural fluid, and bronchoalveolar lavage in addition to cultures of blood, bone, skin, and soft tissues are essential diagnostically. Susceptibility testing of mycobacterial isolates is a basic component of optimal care. Currently, there are no guidelines for the treatment of NTM infections in recipients of stem cell transplantation, but such infections have been successfully treated with surgical debridement, removal of infected or colonized indwelling intravascular devices, and administration of various combinations of antimicrobials. Monotherapy can be associated with development of drug resistance due to new genetic mutation. The accepted duration of treatment is 9 months in allogeneic stem cell transplantation and 6 months in autologous setting. Unfortunately, eradication of NTM infections may be impossible and their treatment is often complicated by adverse effects and interactions with other transplant-related medication.