Multisystem Inflammatory Syndrome of Children: Subphenotypes, Risk Factors, Biomarkers, Cytokine Profiles, and Viral Sequencing.

OBJECTIVE: To assess demographic, clinical, and biomarker features distinguishing patients with multisystem inflammatory syndrome in children (MIS-C); compare MIS-C sub-phenotypes; identify cytokine biosignatures; and characterize viral genome sequences. STUDY DESIGN: We performed a prospective observational cohort study of 124 children hospitalized and treated under the institutional MIS-C Task Force protocol from March to September 2020 at Children's National, a quaternary freestanding children's hospital in Washington, DC. Of this cohort, 63 of the patients had the diagnosis of MIS-C (39 confirmed, 24 probable) and 61 were from the same cohort of admitted patients who subsequently had an alternative diagnosis (controls). RESULTS: Median age and sex were similar between MIS-C and controls. Black (46%) and Latino (35%) children were over-represented in the MIS-C cohort, with Black children at greatest risk (OR 4.62, 95% CI 1.151-14.10; P = .007). Cardiac complications were more frequent in critically ill patients with MIS-C (55% vs 28%; P = .04) including systolic myocardial dysfunction (39% vs 3%; P = .001) and valvular regurgitation (33% vs 7%; P = .01). Median cycle threshold was 31.8 (27.95-35.1 IQR) in MIS-C cases, significantly greater (indicating lower viral load) than in primary severe acute respiratory syndrome coronavirus 2 infection. Cytokines soluble interleukin 2 receptor, interleukin [IL]-10, and IL-6 were greater in patients with MIS-C compared with controls. Cytokine analysis revealed subphenotype differences between critically ill vs noncritically ill (IL-2, soluble interleukin 2 receptor, IL-10, IL-6); polymerase chain reaction positive vs negative (tumor necrosis factor-α, IL-10, IL-6); and presence vs absence of cardiac abnormalities (IL-17). Phylogenetic analysis of viral genome sequences revealed predominance of GH clade originating in Europe, with no differences comparing patients with MIS-C with patients with primary coronavirus disease 19. Treatment was well tolerated, and no children died. CONCLUSIONS: This study establishes a well-characterized large cohort of MIS-C evaluated and treated following a standardized protocol and identifies key clinical, biomarker, cytokine, viral load, and sequencing features. Long-term follow-up will provide opportunity for future insights into MIS-C and its sequelae.

Clinical Utility of Anaerobic and Fungal Blood Cultures in the Pediatric Oncologic Population.

BACKGROUND: If there is a concern for sepsis in a pediatric patient an aerobic blood culture is obtained. A febrile or ill oncology patient will often be evaluated with aerobic, anaerobic, and fungal blood cultures. There is to our knowledge little evidence to confirm the added benefit of broadly obtaining these cultures. METHODS: A retrospective analysis of blood cultures from patients in the oncology and hematopoietic stem cell transplant wards at Children's National Medical Center between January 2010 and April 2017. Positive anaerobic and fungal cultures were evaluated for corollary positive aerobic cultures from the same time frame (+/-24 h). Unique isolates were designated as those positive anaerobic and fungal cultures without positive aerobic cultures and evaluated with detailed chart review. RESULTS: A total of 10,950 cultures were evaluated during the study period: 6579 aerobic, 2391 anaerobic cultures, 1980 fungal. In total, 419 positive aerobic, 140 positive anaerobic, and 43 positive fungal cultures were reviewed. Among these, 22 unique anaerobic cultures and 21 unique fungal cultures met case criteria. Only 7 cultures of obligate anaerobes were observed: 4 Clostridial spp., 2 Propionobacterium acnes, and 1 Peptostreptococcus spp. Thirteen of 21 fungal isolates consisted of a single colony and were regarded as probable contaminants. Penicillium, Cladosporium, and dematiaceous molds were in greatest frequency. Potential risk factors for patients with breakthrough isolates were evaluated and described. CONCLUSIONS: There is little increased yield from the use fungal and anaerobic blood cultures in addition to aerobic blood cultures in the routine evaluation of pediatric oncology and bone marrow transplant patients. Fungal and anaerobic blood cultures and should be reserved for cases with high clinical suspicion.

Central Line-Associated Mucor velutinosus Bloodstream Infection in an Immunocompetent Pediatric Patient.

We report here the isolation of Mucor velutinosus from multiple blood cultures performed on samples from Broviac catheters and culture of a Broviac insertion-site wound sample from a 6-year-old boy with a history of intestinal failure secondary to chronic intestinal pseudo-obstruction, parenteral nutrition, and jejunostomy tube dependence. Examination of a slide from the culture revealed the presence of wide nonseptate hyphae with sporangiophores, columella, and chlamydospores. The fungal isolate was sent to the National Institutes of Health for further evaluation and was identified as Mucor velutinosus by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and genomic sequencing. The patient was treated successfully with intravenous amphotericin B and prompt removal of his central line. To the best of our knowledge, this is the first case of M velutinosus bloodstream infection in a child without cancer.

Different next generation sequencing platforms produce different microbial profiles and diversity in cystic fibrosis sputum.

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disease characterized by recurrent lung infections. Studies of the lung microbiome have shown an association between decreasing diversity and progressive disease. 454 pyrosequencing has frequently been used to study the lung microbiome in CF, but will no longer be supported. We sought to identify the benefits and drawbacks of using two state-of-the-art next generation sequencing (NGS) platforms, MiSeq and PacBio RSII, to characterize the CF lung microbiome. Each has its advantages and limitations. METHODS: Twelve samples of extracted bacterial DNA were sequenced on both MiSeq and PacBio NGS platforms. DNA was amplified for the V4 region of the 16S rRNA gene and libraries were sequenced on the MiSeq sequencing platform, while the full 16S rRNA gene was sequenced on the PacBio RSII sequencing platform. Raw FASTQ files generated by the MiSeq and PacBio platforms were processed in mothur v1.35.1. RESULTS: There was extreme discordance in alpha-diversity of the CF lung microbiome when using the two platforms. Because of its depth of coverage, sequencing of the 16S rRNA V4 gene region using MiSeq allowed for the observation of many more operational taxonomic units (OTUs) and higher Chao1 and Shannon indices than the PacBio RSII. Interestingly, several patients in our cohort had Escherichia, an unusual pathogen in CF. Also, likely because of its coverage of the complete 16S rRNA gene, only PacBio RSII was able to identify Burkholderia, an important CF pathogen. CONCLUSION: When comparing microbiome diversity in clinical samples from CF patients using 16S sequences, MiSeq and PacBio NGS platforms may generate different results in microbial community composition and structure. It may be necessary to use different platforms when trying to correctly identify dominant pathogens versus measuring alpha-diversity estimates, and it would be important to use the same platform for comparisons to minimize errors in interpretation.

Empiric Monotherapy Versus Combination Therapy for Enterobacteriaceae Bacteremia in Children.

BACKGROUND: Bacteremia caused by members of the Enterobacteriaceae can be life threatening. Appropriate antimicrobial therapy is critical to reducing morbidity and mortality. METHODS: This retrospective cohort study (2008-2011) was conducted in children and young adults (<21 years of age) hospitalized with Enterobacteriaceae bacteremia with clinical signs and symptoms of infection. We investigated whether combination empiric antimicrobial therapy was superior to monotherapy for treatment. Monotherapy was defined as empiric therapy with a ß-lactam agent alone. Combination therapy was defined as coadministration of a ß-lactam agent with an aminoglycoside agent for at least 48 hours before the susceptibility data were known. Outcome was measured as the response to therapy (defined as the time to negative blood culture) and was compared among patients administered monotherapy versus combination therapy. RESULTS: Of 203 episodes of Enterobacteriaceae bacteremia, 78 (38%) were caused by Klebsiella spp, 73 (36%) were caused by Escherichia coli, and 52 (26%) were caused by Enterobacter spp. Of 203 episodes of bacteremia caused by 3 organisms of greatest interest, 101 (50%) were treated with combination therapy. Patients with cancer were more likely to receive combination therapy (38% vs. 16%; P < 0.001); patients with gastrointestinal disease and those receiving total parenteral nutrition were more likely to receive monotherapy (58% vs. 39%; P = 0.006 and 54% vs. 37%; P = 0.013, respectively). There was no difference in outcome in patients receiving monotherapy versus combination therapy (P = 0.86). CONCLUSION: Combination therapy consisting of a ß-lactam agent and an aminoglycoside agent was not superior to monotherapy with a ß-lactam agent alone for managing Enterobacteriaceae bacteremia in children and young adults.

Risk factors for molecular detection of adenovirus in pediatric hematopoietic stem cell transplantation recipients.

Adenovirus (AdV) infections are a major cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). To evaluate the use of molecular AdV testing in HSCT at our institution and identify risk factors for AdV viremia and disease, we performed a retrospective cohort study of all HSCT recipients who had undergone AdV polymerase chain reaction testing over a 2-year period. Two cohorts were identified: cohort 1, comprising patients testing positive for AdV (n = 7) and cohort 2, comprising patients testing negative (n = 36). Overall patient characteristics were not statistically significantly different between the 2 cohorts. A comparison of cohort 1 and cohort 2 identified the following medication exposures as risk factors influencing AdV status: preparatory regimens using fludarabine (relative risk [RR], 8.73; 95% confidence interval [CI], 1.18-64.27; P = .006), melphalan (RR, 3.47; 95% CI, 0.76-15.94: P = .08), and/or cyclophosphamide (RR, 0.18; 95% CI, 0.02-1.4; P = .05), and GVHD prophylaxis with methylprednisone (RR, 3.73; 95% CI, 1.01-13.9; P = .04). AdV-positive patients had higher grades of GVHD and higher rates of GVHD of the gastrointestinal tract (RR, 4; 95% CI, 1.18-13.5; P = .03) compared with AdV-negative patients. Four of the 7 AdV-positive patients had concomitant clinical manifestations of disease, including pneumonia, diarrhea, and/or disseminated disease. Clinical outcomes in symptomatic patients included resolution of disease in 2 patients and death in 2 patients. All 7 AdV-positive patients received antiviral therapy, including 1 patient with severe disseminated disease that resolved after administration of liposomal cidofovir. Our study at a large pediatric HSCT center provides important preliminary data for the development of a prospective trial destined to identify specific HCST patient subpopulations that might benefit most from molecular screening and early preemptive therapy.

Control of vancomycin-resistant enterococci in the neonatal intensive care unit.

BACKGROUND AND OBJECTIVE: Multidrug-resistant organisms (MDROs), such as vancomycin-resistant enterococci (VRE), cause serious infections, especially among high-risk patients in NICUs. When VRE was introduced and transmitted in our NICU despite recommended infection control practices, we instituted active surveillance cultures to determine their efficacy in detecting and controlling spread of VRE among high-risk infants. METHODS: Active surveillance cultures, other infection control measures, and a mandatory in-service education module on preventing MDRO transmission were implemented. Cultures were performed on NICU admission and then weekly during their stay. Molecular DNA fingerprinting of VRE isolates facilitated targeting efforts to eliminate clonal spread of VRE. Repetitive sequence PCR (rep-PCR)-based DNA fingerprinting was used to compare isolates recovered from patients with VRE infection or colonization. Environmental VRE cultures were performed around VRE-colonized or -infected patients. DNA fingerprints were prepared from the products of rep-PCR amplification and analyzed using software to determine strain genetic relatedness. RESULTS: Active surveillance cultures identified 65 patients with VRE colonization or infection among 1,820 admitted to the NICU. Rep-PCR performed on 60 VRE isolates identified 3 clusters. Cluster 1 included isolates from 21 patients and 4 isolates from the environment of the index patient. Clusters 2 and 3 included isolates from 23 and 3 patients, respectively. Similarity coefficients among the members of each cluster were 95% or greater. CONCLUSIONS: Control of transmission of multi-clonal VRE strains was achieved. Active surveillance cultures, together with implementation of other infection control measures, combined with rep-PCR DNA fingerprinting were instrumental in controlling VRE transmission in our NICU.

Cluster of Trichosporon mucoides in children associated with a faulty bronchoscope.

BACKGROUND: Several outbreaks of Pseudomonas aeruginosa infection associated with a specific model of fiberoptic bronchoscope have been reported. In a 3-week period in September 2000, we noticed an increased number of Trichosporon mucoides isolates recovered from bronchoalveolar lavage (BAL) specimens collected at our hospital. We investigated the circumstances surrounding these isolates. METHODS: Outbreak investigation was conducted, and the medical records of the affected patients were reviewed retrospectively for evidence of positive cultures for T. mucoides from BAL specimens. Specimens collected during the investigation were inoculated onto fungal culture medium and yeasts were identified with API-20C (BioMèrieux-Vitek). RESULTS: During the 3-week period BAL specimens from six patients yielded growth of T. mucoides. These six high risk patients had emergency bronchoscopy performed as a workup for pneumonia and/or respiratory distress. A Model BF XP-40 bronchoscope (Olympus) had been used in all six patients. Cultures of the bronchoscope (external body and the lumen), bronchoscope disinfector, 2% glutaraldehyde disinfecting solution and water filters/supply were performed. Only fluid from the bronchoscope lumen yielded growth of T. mucoides. Air sample cultures of the bronchoscopy suites were negative. Medical records review disclosed that affected patients were not readmitted with infection with T. mucoides and had no adverse outcomes. The bronchoscope was removed from service and returned to the manufacturer. CONCLUSION: Routine surveillance and aggressive investigation identified persistent T. mucoides contamination of one bronchoscope. The bronchoscope manufacturer later recalled the BF XP-40 model for corrective revision.