Mycobacterium abscessus Infections in Children: A Review of Current Literature

Epidemiology of Mycobacterium abscessus

BACKGROUND

Nontuberculous mycobacteria (NTM) are highly abundant in soil, dust, and water sources, making human-pathogen contact frequent and recurrent. NTM represents over 200 species/subspecies; some are considered strict or opportunistic pathogens. Mycobacterium abscessus, often regarded as one of the most antibiotic-resistant mycobacteria, is the second most frequent NTM pulmonary disease pathogen.

OBJECTIVES

To describe the epidemiology of M. abscessus through a literature review focusing on clinical aspects.

SOURCES

We conducted searches on PubMed and Web of Knowledge for articles published from 2010 to the present using the keywords 'Mycobacterium abscessus', 'Nontuberculous mycobacteria', and 'epidemiology'. Our search prioritized original reports on the occurrence of NTM and M. abscessus infection/disease.

CONTENT

Advanced molecular and genetic diagnostic techniques have refined the M. abscessus complex (MABC) microbiological classification over the last few decades. MABC can adhere to surfaces and form a biofilm. This characteristic and its resistance to common disinfectants allow these microorganisms to persist in the water distribution systems, becoming a constant reservoir. The frequency and manifestation of NTM species vary geographically because of environmental conditions and population susceptibility differences. MABC lung disease, the most frequent site of NTM infection in humans, is often seen in patients with underlying lung diseases such as bronchiectasis, whereas MABC disseminated disease is related to immunosuppression. Skin and soft tissue infections are associated with surgical or injection procedures. Epidemiological evidence suggests an overall increase in MABC infection and disease in the last decade.

IMPLICATIONS

Establishing the burden of this disease is challenging because of varying measures of incidence and prevalence, referral bias, and differences in medical practices and reporting. Furthermore, environmental and structural determinants, infection routes, and MABC pulmonary disease mechanisms require additional investigation. This review contributes to a better understanding of the epidemiology of MABC, which could inform clinical practice and future research.

Peritoneal dialysis-associated infection caused by Mycobacterium abscessus in a pediatric patient on continuous peritoneal dialysis without switching to hemodialysis

Most peritoneal dialysis (PD)-associated infections caused by Mycobacterium abscessus (M. abscessus) require a transfer from PD to hemodialysis (HD). Here, we report a pediatric case of exit-site and tunnel infections caused by M. abscessus, for whom PD was continued with catheter replacement, debridement of the infected site, and the administration of multiple antibacterial agents. A 10-year-old boy with end-stage kidney disease secondary to juvenile nephronophthisis with NPHP1 deletion, for whom PD was initiated at the age of 9 years, was admitted to the hospital with complaints of fever, pus at the exit-site of the PD catheter, and poor PD drainage. The dialysis effluent culture results were negative; however, M. abscessus was detected in the pus at the exit-site of the PD catheter. The management of HD was expected to be challenging owing to the presence of developmental disorders. Therefore, PD was continued with the simultaneous removal of the PD catheter, reinsertion of a new catheter at a new site, and debridement of the infected site. Multiple antibacterial therapies were administered for 2 months, and the patient was eventually discharged without switching to HD. To the best of our knowledge, this is the first pediatric case of a PD-associated infection caused by M. abscessus, for whom PD was continued without switching to HD. This treatment strategy is not generally recommended but may be an option for patients without peritonitis who have difficulty switching to HD.

Cutaneous Mycobacterium Abscessus Infection Following Plastic Surgery: Three Case Reports

Aim

Mycobacterium abscessus is ubiquitous in the environment and seldom causes infections in immunocompetent individuals. However, skin and soft tissue infections caused by M. abscessus have been reported in recent years. Additionally, the cutaneous infections or outbreaks post cosmetic surgery caused by M. abscessus have been increasing due to the popularity of plastic surgery. The main modes of transmission are through contaminated saline, disinfectants, or surgery equipment, as well as close contact between patients. This article describes three patients who were admitted to our hospital between November 2019 and October 2020. They presented with long-term non-healing wounds caused by M. abscessus infection after undergoing plastic surgery. Symptoms presented by the three patients included swelling, ulceration, secretion, and pain. After identification of M. abscessus with Ziehl-Neelsen staining and MALDI-TOF MS system, the patients were treated with surgical debridement and clarithromycin.

Conclusion

It is important to note that a long-term wound that does not heal, especially after plastic surgery, should raise suspicion for M. abscessus infection. The infection mechanism in these three patients may have been due to exposure to surgical equipment that was not properly sterilized or due to poor sterile technique by the plastic surgeon. To prevent such infections, it is important to ensure proper sterilization of surgical equipment and saline.

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.

A case of a preschool child with a successful kidney transplant following the long-term administration of antibiotics to treat peritoneal dialysis-related ESI/peritonitis by Mycobacterium abscessus

A preschool child with refractory peritoneal dialysis-related exit-site infection (ESI)/peritonitis caused by Mycobacterium abscessus (M. abscessus) received multidrug antibacterial therapy for 6 months and then successfully underwent living-donor kidney transplantation. The patient was a 2.7-year-old boy and the primary disease was bilateral hypo/dysplastic kidneys. Peritoneal dialysis (PD) was initiated at the age of 4 months. Purulent drainage from the PD catheter exit site was observed, and pus and PD effluent cultures were negative. Since living kidney transplantation was scheduled for 2 months later, the PD catheter was replaced. Due to dialysate leakage from the exit site, the new PD catheter was removed and hemodialysis was initiated. M. abscessus subsequently grew from the PD effluent and abscesses that formed at the exit site continued to present bacteria even after catheter removal; therefore, additional debridement was performed. He received combination treatment with antibiotics, amikacin, clarithromycin, imipenem/cilastatin sodium, and tigecycline, for 6 months. After a 4-month observation period without antibiotics, the patient underwent living-donor kidney transplantation. The post-transplantation course was uneventful without the recurrence of infection for 2 years. Although PD-related ESI/peritonitis caused by M. abscessus was intractable, PD catheter removal, multiple debridement, and 6-month antibiotic combination therapy led to improvements. Follow-up observations for 4 months after the cessation of antibacterial treatment confirmed no recurrence of M. abscessus infection, which allowed kidney transplantation. The establishment of an appropriate treatment strategy and observation period for M. abscessus infection ahead of kidney transplantation requires further case accumulation.

Pulmonary Mycobacterium abscessus Infection in an 11-Year-Old Child, Successfully Treated with Inhaled/Parenteral Amikacin: A Case Report and Review of Literature

Mycobacterium abscessus appears to be increasing cause of pulmonary infection in children with underlying risk factors including cystic fibrosis, chronic lung disease and immunodeficiency syndromes. We present a case of pulmonary M. abscessus infection in a pediatric patient with primary ciliary dyskinesia and he was successfully treated with parenteral amikacin, linezolid and oral clarithromycin combined with inhaled amikacin. Clinical improvement was observed after adding inhaled amikacin to the treatment.

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.

Mycobacterium abscessus Soft Tissue Infection: Review of Published Cases and Challenges in Treatment

We report the first case of Mycobacterium abscessus soft tissue infection following a firearm injury. We summarize previous published cases of M. abscessus soft tissue infection and review the current evidence on management.

Top Questions in the Diagnosis and Treatment of Pulmonary M. abscessus Disease

Mycobacterium abscessus disease is particularly challenging to treat, given the intrinsic drug resistance of this species and the limited data on which recommendations are based, resulting in a greater reliance on expert opinion. We address several commonly encountered questions and management considerations regarding pulmonary Mycobacterium abscessus disease, including the role of subspecies identification, diagnostic criteria for determining disease, interpretation of drug susceptibility test results, approach to therapy including the need for parenteral antibiotics and the role for new and repurposed drugs, and the use of adjunctive strategies such as airway clearance and surgical resection.

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.

Mycobacterium abscessus: Environmental Bacterium Turned Clinical Nightmare

Mycobacteria are a large family of over 100 species, most of which do not cause diseases in humans. The majority of the mycobacterial species are referred to as nontuberculous mycobacteria (NTM), meaning they are not the causative agent of tuberculous (TB) or leprosy, i.e., Mycobacterium tuberculous complex and Mycobacterium leprae, respectively. The latter group is undoubtedly the most infamous, with TB infecting an estimated 10 million people and causing over 1.2 million deaths in 2017 alone TB and leprosy also differ from NTM in that they are only transmitted from person to person and have no environmental reservoir, whereas NTM infections are commonly acquired from the environment. It took until the 1950′s for NTM to be recognised as a potential lung pathogen in people with underlying pulmonary disease and another three decades for NTM to be widely regarded by the medical community when Mycobacterium avium complex was identified as the most common group of opportunistic pathogens in AIDS patients. This review focuses on an emerging NTM called Mycobacterium abscessus (M. abs). M. abs is a rapidly growing NTM that is responsible for opportunistic pulmonary infections in patients with structural lung disorders such as cystic fibrosis and bronchiectasis, as well as a wide range of skin and soft tissue infections in humans. In this review, we discuss how we came to understand the pathogen, how it is currently treated and examine drug resistance mechanisms and novel treatments currently in development. We highlight the urgent need for new and effective treatments for M. abs infection as well as improved in vivo methods of efficacy testing.