Infections Caused by Rapidly Growing Mycobacteria spp in Children and Adolescents With Cancer

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.

NonTuberculous Mycobacteria Blood Stream Infection in Pediatric and Adult Patients: 15 Years Surveillance

BACKGROUND

Nontuberculous Mycobacteria (NTM) are rare causes of bloodstream infection (BSI). This study addresses the management and prognosis of NTM BSI and the differences between adult and pediatric patients.

METHODS

We retrospectively reviewed the medical charts of patients at any age with NTM BSI, from January 1, 2005, to June 30, 2020. Data on demographics, underlying conditions, clinical manifestations, NTM species, antibiotic treatments and outcomes were retrieved.

RESULTS

Positive blood cultures for NTM were detected in 43 patients, 30 children and 13 adults. Median age: 10.37 years (IQR 6.692-39.864). Thirty-seven (86%) patients had an active malignant disease. Fever was the chief sign in 23 (53.5%) patients and pulmonary manifestations in 14 (32.6%). Rapidly growing NTM comprised 39 (90.7%) of the isolates. Central venous catheter (CVC) was documented in 39 (90.7%) cases, 31 (79.5%) of which were removed as part of treatment. Antibiotic treatment directed against NTM was documented in 26 (60.5%) patients. CVC was removed in 7/17 patients who were not treated with antibiotics. Relapse occurred in 3 cases; no 30-days mortality was reported. Children and adults had similar clinical characteristics. However, children had a higher rate of CVC at the time of bacteremia and a higher chance to receive treatment.

CONCLUSION

NTM BSI was seen mainly in oncologic patients with CVC. Children and adults had a similar disease course and outcome. Relapse was rare and NTM-related mortality was not reported.

Investigation of two cases of Mycobacterium chelonae infection in haemato-oncology patients using whole-genome sequencing and a potential link to the hospital water supply

BACKGROUND

Haemato-oncology patients are at increased risk of infection from atypical mycobacteria such as Mycobacterium chelonae which are commonly found in both domestic and hospital water systems.

AIMS

To describe the investigation and control measures following two patient cases of M. chelonae and positive water samples in the study hospital.

METHODS

Water testing was undertaken from outlets, storage tanks and mains supply. Whole-genome sequencing (WGS) was used to compare patient and positive water samples. The subsequent infection control measures implemented are described.

FINDINGS

The WGS results showed two main populations of M. chelonae within the group of sampled isolates. The results showed that the patient strains were unrelated to each other, but that the isolate from one patient was closely related to environmental samples from water outlets, supporting nosocomial acquisition.

CONCLUSIONS

WGS was used to investigate two patient cases of M. chelonae and positive water samples from a hospital water supply. Relevant control measures and the potential for chemical dosing of water systems to enhance proliferation of atypical mycobacteria are discussed.

Catheter-related blood stream infection caused by Mycobacterium chelonae in a child with myeloid leukemia associated with Down syndrome

Rapidly growing nontuberculous mycobacteria should be considered if GPRs gram-positive rods are detected in blood cultures 2-3 days after the blood sample collection.

Mycobacterium mucogenicum bacteremia in an immunocompetent host: A case report and concise review

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M. mucogenicum should be considered as a potential etiology of bacteremia in the setting of an inserted catheter, even in immunocompetent hosts.

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M. mucogenicum is one of the most common causes of rapidly growing mycobacterium bloodstream infection in patients with catheters in place.

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Catheter removal is critical in the management of patients with M. mucogenicum bacteremia since mycobacteria is notorious for biofilm formation.

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M. mucogenicum is naturally resistant to anti-tuberculous drugs.

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M. mucogenicum is susceptible to numerous antibiotics, making early recognition and diagnosis important to tailor appropriate therapy.

Rapidly growing mycobacterium (RGM) bloodstream infections (BSI) have been described in the literature mostly in immunocompromised patients such as those with malignancies. Here, we describe a case of a RGM, Mycobacterium mucogenicum, bloodstream infection in an immunocompetent host who was receiving antibiotics via a peripherally inserted central catheter (PICC).

False-positive blood cultures: The need for follow-up

The diagnosis of blood-borne infections in immunocompromised patients is a major challenge for the clinical microbiology laboratory. Isolation of bloodborne pathogens in these patients has profound clinical implications, yet is fraught with technical problems, including the presence of unusual and difficult to isolate pathogens. Coupled with this is the problem of false-positive blood culture signals from automated blood culture systems which further delays the definitive diagnosis. Here, we present a case of an 8-year-old boy with Ph +ve acute lymphoblastic leukaemia who has repeated 'false positive' blood cultures and later grew an uncommon organism.

Current significance of the Mycobacterium chelonae-abscessus group

Organisms of the Mycobacterium chelonae-abscessus group can be significant pathogens in humans. They produce a number of diseases including acute, invasive and chronic infections, which may be difficult to diagnose correctly. Identification among members of this group is complicated by differentiating at least eleven (11) known species and subspecies and complexity of identification methodologies. Treatment of their infections may be problematic due to their correct species identification, antibiotic resistance, their differential susceptibility to the limited number of drugs available, and scarcity of susceptibility testing.

Mycobacterium abscessus Infections in Children: A Review of Current Literature

There is limited literature on Mycobacterium abscessus infections in children and limited data about its diagnosis and management. The incidence of infections due to M abscessus appears to be increasing in certain populations and can be a significant cause of morbidity and mortality.Management of these infections is challenging and relies on combination antimicrobial therapy and debridement of diseased tissue, depending on the site and extent of disease. Treatment regimens often are difficult to tolerate, and the antimicrobials used can cause significant adverse effects, particularly given the long duration of therapy needed.This review summarizes the literature and includes information from our own institution's experience on pediatric M abscessus infections including the epidemiology, transmission, clinical manifestations, and the management of these infections. Adult data have been used where there are limited pediatric data. Further studies regarding epidemiology and risk factors, clinical presentation, optimal treatment, and outcomes in children are necessary.

A totally implantable venous access port associated with bloodstream infection caused by Mycobacterium fortuitum: A case report

RATIONALE

Rapidly growing mycobacteria (RGM) are well-known causative agents of human infections, particularly in immunocompromised hosts. However, Mycobacterium fortuitum, a predominant organism, in catheter-associated infections, has rarely been documented in totally implantable venous access port (TVIAP)-associated bloodstream infections.

PATIENT CONCERNS

A 25-year-old woman with breast cancer presented to hospital with repeated fever for several days. The patient first refused to remove the TVIAP in her body, and had a relapse of M. fortuitum bacteraemia four months later.

DIAGNOSES

Bacteria isolated from patient's blood and TVIAP were identified as M. fortuitum by Matrix-assisted laser desorption/ionization-time of flight spectrometry and bacterial 16s rDNA sequencing. The patient was diagnosed as a TVIAP-associated bloodstream infection.

INTERVENTIONS

The TVIAP was eventually surgically removed, and M. fortuitum was found to have localized on the tip of the catheter. The patient was treated by anti-infection therapy.

OUTCOMES

The patient was treated with 4 weeks of intravenous amikacin and levofloxacin followed by 4 weeks of oral levofloxacin. No episodes of fever occurred during the follow-up to date.

LESSONS

RGM infections remain a challenging issue for TIVAPs. Accurate species identification, timely intravascular catheter removal and appropriate antibiotic therapy are recommended to ensure successful outcomes.

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.

Nontuberculous Mycobacteria in Children: A Focus on Bloodstream Infections

BACKGROUND

Nontuberculous mycobacteria (NTM) are ubiquitous organisms with variable disease-causing potential. Bloodstream infections caused by NTM in children are poorly described.

METHODS

We describe a retrospective case series of children with culture-confirmed mycobacterial disease managed at the Children's Hospital at Westmead between July 2005 and June 2015.

RESULTS

Sixty-five patients had 149 positive NTM cultures; 55 (83.0%) episodes in 54 patients were considered clinically significant. Of the 54 children who met criteria for NTM disease, 25 (46.3%) had lymphadenitis, 13 (24.1%) lung disease, 8 (14.8%) had soft tissue infection or osteomyelitis and 8 (14.8%) had bacteremia. All children with bacteremia had a central venous catheter; those with pulmonary infection had underlying lung disease and all children with soft tissue infection or osteomyelitis had a history of recent penetrating injury. Disease caused by Mycobacterium avium-intracellulare complex was most common, accounting for 19 (76.0%) and 7 (53.8%) lymph node and lung infections, respectively. The most frequently isolated rapid growing mycobacteria were Mycobacterium fortuitum (8; 15%) and Mycobacterium abscessus (6; 11%), with M. fortuitum accounting for the majority (6; 75%) of bloodstream infections. Six (75%) patients with bacteremia had their intravenous catheter removed and all had a favorable outcome. A single disease relapse was reported in 1 of 2 patients with a retained catheter.

CONCLUSION

Lymphadenitis was the most common NTM disease manifestation and not associated with comorbidity. NTM bacteremia was always associated with a central line and catheter removal with cure. We were unable to assess the added value of various antibiotic regimens.

Laboratory Diagnosis of Infections in Cancer Patients: Challenges and Opportunities

Infections remain a significant cause of morbidity and mortality in cancer patients. The differential diagnosis for these patients is often wide, and the timely selection of the right clinical tests can have a significant impact on their survival. However, laboratory findings with current methodologies are often negative, challenging clinicians and laboratorians to continue the search for the responsible pathogen. Novel methodologies are providing increased sensitivity and rapid turnaround time to results but also challenging our interpretation of what is a clinically significant pathogen in cancer patients. This minireview provides an overview of the most common infections in cancer patients and discusses some of the challenges and opportunities for the clinical microbiologist supporting the care of cancer patients.

Infectious complications in children with acute lymphoblastic leukemia treated in low-middle-income countries

Infections are the most important cause of morbidity and mortality in children treated for acute lymphoblastic leukemia (ALL). The rates of infection-associated mortality are up to 10-times higher in low- and middle-income countries (LMIC) than in high-income countries. The prevention, early recognition and management of infectious complications is especially challenging in LMIC because of disease and poverty-related factors, as well as the shortage of trained personnel, supplies, diagnostic tools and adequate organizational infrastructure. Children in LMIC with ALL, who are frequently underweight, are at increased risk of community-acquired pathogens, nosocomial multidrug-resistant pathogens and opportunistic microorganisms. This review summarizes the challenges of managing the major categories of infections in children receiving treatment for ALL and provides updated practical recommendations for preventing and managing these infections in LMIC.