Endotoxin Acts Synergistically With Clostridioides difficile Toxin B to Increase Interleukin 1ß Production: A Potential Role for the Intestinal Biome in Modifying the Severity of C. difficile Colitis.

BACKGROUND: Inflammation is a crucial driver of host damage in patients with Clostridioides difficile colitis. We examined the potential for the intestinal microbiome to modify inflammation in patients with C. difficile colitis via the effects of gut-derived endotoxin on cytokine production. METHODS: Endotoxin from Escherichia coli and Pseudomonas aeruginosa as well as stool-derived endotoxin were tested for their ability to enhance interleukin 1ß (IL-1ß) and tumor necrosis factor alpha (TNF-α) production by toxin B-stimulated peripheral blood mononuclear cells. Inflammasome and Toll-like receptor 4 (TLR4) blocking studies were done to discern the importance of these pathways, while metagenomic studies were done to characterize predominant organisms from stool samples. RESULTS: Endotoxin significantly enhanced the ability of C. difficile toxin B to promote IL-1ß production but not TNF-α. The magnitude of this effect varied by endotoxin type and was dependent on combined inflammasome and TLR4 activation. Stool-derived endotoxin exhibited a similar synergistic effect on IL-1ß production with less synergy observed for stools that contained a high proportion of γ-proteobacteria. CONCLUSIONS: The ability of endotoxin to enhance IL-1ß production highlights a manner by which the microbiome can modify inflammation and severity of C. difficile disease. This information may be useful in devising new therapies for severe C. difficile colitis.

Severe Acute Respiratory Syndrome Coronavirus 2 Clinical Syndromes and Predictors of Disease Severity in Hospitalized Children and Youth.

OBJECTIVE: To characterize the demographic and clinical features of pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) syndromes and identify admission variables predictive of disease severity. STUDY DESIGN: We conducted a multicenter, retrospective, and prospective study of pediatric patients hospitalized with acute SARS-CoV-2 infections and multisystem inflammatory syndrome in children (MIS-C) at 8 sites in New York, New Jersey, and Connecticut. RESULTS: We identified 281 hospitalized patients with SARS-CoV-2 infections and divided them into 3 groups based on clinical features. Overall, 143 (51%) had respiratory disease, 69 (25%) had MIS-C, and 69 (25%) had other manifestations including gastrointestinal illness or fever. Patients with MIS-C were more likely to identify as non-Hispanic black compared with patients with respiratory disease (35% vs 18%, P = .02). Seven patients (2%) died and 114 (41%) were admitted to the intensive care unit. In multivariable analyses, obesity (OR 3.39, 95% CI 1.26-9.10, P = .02) and hypoxia on admission (OR 4.01; 95% CI 1.14-14.15; P = .03) were predictive of severe respiratory disease. Lower absolute lymphocyte count (OR 8.33 per unit decrease in 109 cells/L, 95% CI 2.32-33.33, P = .001) and greater C-reactive protein (OR 1.06 per unit increase in mg/dL, 95% CI 1.01-1.12, P = .017) were predictive of severe MIS-C. Race/ethnicity or socioeconomic status were not predictive of disease severity. CONCLUSIONS: We identified variables at the time of hospitalization that may help predict the development of severe SARS-CoV-2 disease manifestations in children and youth. These variables may have implications for future prognostic tools that inform hospital admission and clinical management.

Fitz-Hugh-Curtis syndrome in adolescent and young adult females: Utility of a decision rule.

BACKGROUND: The diagnosis of Fitz-Hugh-Curtis syndrome (FHC) is often missed or delayed in patients with right upper quadrant pain (RUQ). OBJECTIVE: To develop a decision rule that predicts FHC in females with RUQ pain based on a constellation of historical features, physical examination findings and laboratory results. METHODS: We conducted a prospective study to test the utility of our FHC decision rule in sexually active females, aged 13-20 years, with RUQ pain who were seen in an urban ED over 57 months. The decision rule was based on 4 features: 1. Presence of pleuritic chest pain, 2. Tenderness over the anterior border of liver, 3. History of worsening pain on R lateral position and 4. An erythrocyte sedimentation rate > 30 mm/h. The rule was considered positive if all 4 features were present. FHC was diagnosed in patients with RUQ pain and a positive GEN-PROBE Aptima Combo Assay for either gonorrhea or chlamydia on urine or endocervical specimens. RESULTS: 130 patients were enrolled. 24 were excluded, leaving 106 (81.5%) for analysis. 34/106 (32%) had STI/FHC. There were no differences in mean age or sexual characteristics between those with and without STI/FHC. A positive FHC decision rule had a positive predictive value of 75% (95%CI: 46.8%-91.1%) based on 96 cases for whom all features were available for analysis. CONCLUSION: Our decision rule shows promise in allowing for the early identification of FHC in adolescent and young adult females. Additional study is needed to corroborate these findings and test its generalizability.

The Other Side of the Coin: Anti-inflammatory Antibody Therapy for Infectious Diseases.

The inflammatory response to the fungus Pneumocystis jirovecii plays a central role in the respiratory failure associated with Pneumocystis pneumonia. To help ameliorate the inflammatory response, corticosteroids are used as an adjuvant to standard antimicrobial therapy. Corticosteroids, however, can have a wide range of effects (including deleterious effects) on the host immune response. To date, pathogen-specific antibody therapy has primarily been developed for both its direct antimicrobial activity (e.g., toxin and viral neutralization) and its ability to enhance the antimicrobial activity of the host immune response via effector cells, like macrophages and neutrophils. In this issue of Infection and Immunity, Hoy et al. (Z. Hoy, T. W. Wright, M. Elliott, J. Malone, et al., Infect Immun 88:e00640-19, 2020, https://doi.org/10.1128/IAI.00640-19) report on a surprising application of Pneumocystis-specific antibody therapy in treating disease by decreasing the inflammatory response. This effect appears to occur as a result of an enhanced phagocytic activity within the lung and an associated alteration in the macrophage phenotype. This study adds insight into our understanding of antibody activity and highlights the possibility of using antibody therapy to limit inflammation for other infectious diseases in which inflammatory damage plays a significant role in disease pathogenesis.

Clinical Characteristics and Outcomes of Hospitalized and Critically Ill Children and Adolescents with Coronavirus Disease 2019 at a Tertiary Care Medical Center in New York City.

OBJECTIVE: To describe the clinical profiles and risk factors for critical illness in hospitalized children and adolescents with coronavirus disease 2019 (COVID-19). STUDY DESIGN: Children 1 month to 21 years of age with COVID-19 from a single tertiary care children's hospital between March 15 and April 13, 2020 were included. Demographic and clinical data were collected. RESULTS: In total, 67 children tested positive for COVID-19; 21 (31.3%) were managed as outpatients. Of 46 admitted patients, 33 (72%) were admitted to the general pediatric medical unit and 13 (28%) to the pediatric intensive care unit (PICU). Obesity and asthma were highly prevalent but not significantly associated with PICU admission (P = .99). Admission to the PICU was significantly associated with higher C-reactive protein, procalcitonin, and pro-B type natriuretic peptide levels and platelet counts (P < .05 for all). Patients in the PICU were more likely to require high-flow nasal cannula (P = .0001) and were more likely to have received Remdesivir through compassionate release (P < .05). Severe sepsis and septic shock syndromes were observed in 7 (53.8%) patients in the PICU. Acute respiratory distress syndrome was observed in 10 (77%) PICU patients, 6 of whom (46.2%) required invasive mechanical ventilation for a median of 9 days. Of the 13 patients in the PICU, 8 (61.5%) were discharged home, and 4 (30.7%) patients remain hospitalized on ventilatory support at day 14. One patient died after withdrawal of life-sustaining therapy because of metastatic cancer. CONCLUSIONS: We describe a higher than previously recognized rate of severe disease requiring PICU admission in pediatric patients admitted to the hospital with COVID-19.

Fitz-Hugh-Curtis Syndrome in Adolescent Females: A Diagnostic Dilemma.

Fitz-Hugh-Curtis syndrome is an extrapelvic manifestation of sexually transmitted infections. Partly because of the lack of specific clinical and laboratory features, this diagnosis is often missed or delayed. We describe a series of cases of patients with Fitz-Hugh-Curtis syndrome, where the diagnosis was initially not recognized and patients underwent extensive evaluations for their symptoms. Based on our experience, we also describe shared historical and physical features that may be useful in enhancing the recognition of patients with this disease.

Platelet-activating factor contributes to Bacillus anthracis lethal toxin-associated damage.

The lethal toxin (LeTx) of Bacillus anthracis plays a central role in the pathogenesis of anthrax-associated shock. Platelet-activating factor (PAF) is a potent lipid mediator that has been implicated in endotoxin-associated shock. In this study, we examined the contribution of PAF to the manifestations of lethal toxin challenge in WT mice. LeTx challenge resulted in transient increase in serum PAF levels and a concurrent decrease in PAF acetylhydrolase activity. Inhibition of PAF activity using PAF antagonists or toxin challenge of PAF receptor negative mice reversed or ameliorated many of the pathologic features of LeTx-induced damage, including changes in vascular permeability, hepatic necrosis, and cellular apoptosis. In contrast, PAF inhibition had minimal effects on cytokine levels. Findings from these studies support the continued study of PAF antagonists as potential adjunctive agents in the treatment of anthrax-associated shock.

Cannabidiol's neuroprotective properties and potential treatment of traumatic brain injuries.

Cannabidiol (CBD) has numerous pharmacological targets that initiate anti-inflammatory, antioxidative, and antiepileptic properties. These neuroprotective benefits have generated interest in CBD's therapeutic potential against the secondary injury cascade from traumatic brain injury (TBI). There are currently no effective broad treatment strategies for combating the damaging mechanisms that follow the primary injury and lead to lasting neurological consequences or death. However, CBD's effects on different neurotransmitter systems, the blood brain barrier, oxidative stress mechanisms, and the inflammatory response provides mechanistic support for CBD's clinical utility in TBI. This review describes the cascades of damage caused by TBI and CBD's neuroprotective mechanisms to counter them. We also present challenges in the clinical treatment of TBI and discuss important future clinical research directions for integrating CBD in treatment protocols. The mechanistic evidence provided by pre-clinical research shows great potential for CBD as a much-needed improvement in the clinical treatment of TBI. Upcoming clinical trials sponsored by major professional sport leagues are the first attempts to test the efficacy of CBD in head injury treatment protocols and highlight the need for further clinical research.

Differences in the Clinical Manifestations and Host Immune Responses to SARS-CoV-2 Variants in Children Compared to Adults.

The COVID-19 pandemic challenged the medical field to rapidly identify and implement new approaches to the diagnosis, treatment and prevention of SARS-CoV-2 infections. The scientific community also needed to rapidly initiate basic, translational, clinical and epidemiological studies to understand the pathophysiology of this new family of viruses, which continues to evolve with the emergence of new genetic variants. One of the earliest clinical observations that provided a framework for the research was the finding that, in contrast to most other respiratory viruses, children developed less severe acute and post-acute disease compared to adults. Although the clinical manifestations of SARS-CoV-2 infection changed with each new wave of the pandemic, which was dominated by evolving viral variants, the differences in severity between children and adults persisted. Comparative immunologic studies have shown that children mount a more vigorous local innate response characterized by the activation of interferon pathways and recruitment of innate cells to the mucosa, which may mitigate against the hyperinflammatory adaptive response and systemic cytokine release that likely contributed to more severe outcomes including acute respiratory distress syndrome in adults. In this review, the clinical manifestations and immunologic responses in children during the different waves of COVID-19 are discussed.

Risk factors for Recurrent Clostridioides Difficile Infection in Children.

OBJECTIVE: The aims of this study were to determine the epidemiologic and treatment factors associated with recurrent C. difficile infection in children. METHODS: We conducted a 13-year retrospective review of pediatric C. difficile infections at our institution focusing on the epidemiologic, clinical, and treatment factors associated with recurrent disease. Repeat episodes occurring between 4 weeks and 2 months after initial infection were defined as early recurrences, whereas repeat episodes between 2 and 12 months after initial infection were defined as late recurrences. RESULTS: We identified 303 children with C. difficile infection. Recurrent infections were limited to children with chronic conditions, affecting 27.4% (68 of 248) of this cohort. Early and late recurrences occurred in 36.8 and 63.2% of children, respectively. Among children with a chronic condition, female sex and initial use of metronidazole (as opposed to vancomycin) were associated with recurrent disease in bivariate and multivariate analyses. Overall, there was a high treatment failure rate (34 of 102, 33.3%) once children had developed recurrent disease. CONCLUSIONS: Findings from this study demonstrate the importance of underlying chronic conditions in the development of recurrent C. difficile disease and the shortcomings of current treatment options for recurrent cases. Additionally, our findings indicate that initial treatment selection may impact the likelihood of future disease, with metronidazole usage being associated with higher recurrence rates than vancomycin. These findings highlight the need for additional studies to better understand the implications of C. difficile treatment strategies.

Methylxanthine inhibit fungal chitinases and exhibit antifungal activity.

Chitinases are necessary for fungal cell wall remodeling and cell replication. Methylxanthines have been shown to competitively inhibit family 18 chitinases in vitro. We sought to determine the effects of methylxanthines on fungal chitinases. Fungi demonstrated variable chitinase activity and incubation with methylxanthines (0.5-10 mM) resulted in a dose-dependent decrease in this activity. All fungi tested, except for Candida spp., demonstrated growth inhibition in the presence of methylxanthines at a concentration of 10 mM. India ink staining demonstrated impaired budding and decreased cell size for methylxanthine-treated Cryptococcus neoformans. C. neoformans and Aspergillus fumigatus treated with pentoxifylline also exhibited abnormal cell morphology. In addition, pentoxifylline-treated C. neoformans exhibited increased susceptibility to calcofluor and a leaky melanin phenotype consistent with defective cell wall function. Our data suggest that a variety of fungi express chitinases and that methylxanthines have antifungal properties related to their inhibition of fungal chitinases. Our results highlight the potential utility of targeting chitinases in the development of novel antifungal therapies.

Clinical, Laboratory and Radiographic Features Associated With Prolonged Hospitalization in Children With Complicated Appendicitis.

Objective: In children with appendicitis, rupture of the appendix is associated with a significant increase in morbidity. We sought to characterize the spectrum of illness in children with complicated appendicitis and to define those factors associated with a longer hospital stay. Study Design: We conducted a retrospective review of 132 children, 18 years of age or younger at a large urban teaching hospital in the Bronx, NY between October 2015 and April 2018 with an intraoperative diagnosis of perforated appendix. Clinical, laboratory and radiologic findings were reviewed, and the primary study outcome was length of stay (LOS) dichotomized at the median, which was 7 days. Statistical analyses were done to characterize morbidity and define variables predictive of longer stay. Results: Children in the longer LOS group experienced significantly more morbidity, including ICU stay, ileus, and need for multiple drainage procedures. A longer duration of symptoms prior to presentation was associated with a longer stay. Multivariable logistic regression analysis indicated that the presence of abscess and presence of free fluid in the right upper quadrant (RUQ FF) on initial imaging and C-reactive protein (CRP) level >12 at admission, were independently associated with a longer stay. Conclusion: There is considerable variation in the morbidity of complicated appendicitis. The association between longer stay and the findings of abscess and RUQ FF on initial imaging along with an elevated CRP may provide a useful tool in identifying those children at risk for worse outcomes.

Genomic surveillance of SARS-CoV-2 during the first year of the pandemic in the Bronx enabled clinical and epidemiological inference.

The Bronx was an early epicenter of the COVID-19 pandemic in the USA. We conducted temporal genomic surveillance of SARS-CoV-2 genomes across the Bronx from March-October 2020. Although the local structure of SARS-CoV-2 lineages mirrored those of New York City and New York State, temporal sampling revealed a dynamic and changing landscape of SARS-CoV-2 genomic diversity. Mapping the trajectories of variants, we found that while some became 'endemic' to the Bronx, other, novel variants rose in prevalence in the late summer/early fall. Geographically resolved genomes enabled us to distinguish between cases of reinfection and persistent infection in two pediatric patients. We propose that limited, targeted, temporal genomic surveillance has clinical and epidemiological utility in managing the ongoing COVID pandemic. One sentence summary: Temporally and geographically resolved sequencing of SARS-CoV-2 genotypes enabled surveillance of novel genotypes, identification of endemic viral variants, and clinical inferences, in the first wave of the COVID-19 pandemic in the Bronx.

Genomic surveillance of SARS-CoV-2 during the first year of the pandemic in the Bronx enabled clinical and epidemiological inference.

The Bronx was an early epicenter of the COVID-19 pandemic in the USA. We conducted temporal genomic surveillance of 104 SARS-CoV-2 genomes across the Bronx from March October 2020. Although the local structure of SARS-CoV-2 lineages mirrored those of New York City and New York State, temporal sampling revealed a dynamic and changing landscape of SARS-CoV-2 genomic diversity. Mapping the trajectories of mutations, we found that while some became 'endemic' to the Bronx, other, novel mutations rose in prevalence in the late summer/early fall. Geographically resolved genomes enabled us to distinguish between cases of reinfection and persistent infection in two pediatric patients. We propose that limited, targeted, temporal genomic surveillance has clinical and epidemiological utility in managing the ongoing COVID pandemic.

Proteasome inhibitors prevent caspase-1-mediated disease in rodents challenged with anthrax lethal toxin.

NOD-like receptors (NLRs) and caspase-1 are critical components of innate immunity, yet their over-activation has been linked to a long list of microbial and inflammatory diseases, including anthrax. The Bacillus anthracis lethal toxin (LT) has been shown to activate the NLR Nalp1b and caspase-1 and to induce many symptoms of the anthrax disease in susceptible murine strains. In this study we tested whether it is possible to prevent LT-mediated disease by pharmacological inhibition of caspase-1. We found that caspase-1 and proteasome inhibitors blocked LT-mediated caspase-1 activation and cytolysis of LT-sensitive (Fischer and Brown-Norway) rat macrophages. The proteasome inhibitor NPI-0052 also prevented disease progression and death in susceptible Fischer rats and increased survival in BALB/c mice after LT challenge. In addition, NPI-0052 blocked rapid disease progression and death in susceptible Fischer rats and BALB/c mice challenged with LT. In contrast, Lewis rats, which harbor LT-resistant macrophages, showed no signs of caspase-1 activation after LT injection and did not exhibit rapid disease progression. Taken together, our findings indicate that caspase-1 activation is critical for rapid disease progression in rodents challenged with LT. Our studies indicate that pharmacological inhibition of NLR signaling and caspase-1 can be used to treat inflammatory diseases.

A survey of current and past Pediatric Infectious Diseases fellows regarding training.

BACKGROUND: The objectives of this study were to characterize the satisfaction of Pediatric Infectious Diseases fellows with their training and to understand how opinions about training have changed over time. METHODS: Anonymous survey studies were conducted with questions designed to include areas related to the 6 ACGME core competencies. Surveys for current fellows were distributed by fellowship directors, while surveys for graduates were mailed to all individuals with Pediatric Infectious Diseases certification. RESULTS: Response rates for current fellows and graduates were 50% and 52%, respectively. Most fellows (98%) and graduates (92%) perceived their overall training favorably. Training in most clinical care areas was rated favorably, however both groups perceived relative deficiencies in several areas. Current fellows rated their training in other competency areas (e.g., systems-based practice, research, and ethics) more favorably when compared to past graduates. Recent graduates perceived their training more favorably in many of these areas compared to past graduates. CONCLUSIONS: Pediatric Infectious Diseases fellowship training is well regarded by the majority of current and past trainees. Views of current fellows reflect improved satisfaction with training in a variety of competency areas. Persistent deficiencies in clinical training likely reflect active barriers to education. Additional study is warranted to validate perceived deficiencies and to establish consensus on the importance of these areas to infectious diseases training.

A rat model of neonatal candidiasis demonstrates the importance of lipases as virulence factors for Candida albicans and Candida parapsilosis.

The host factors that contribute to the increased susceptibility of preterm neonates to invasive candidiasis have not been fully identified. In addition, there has been a lack of suitable models to study this problem. We show that rat pups, similar to premature neonates, display increased susceptibility to experimental Candida albicans infection. Further, we find that both C. albicans and Candida parapsilosis lipase disruptant mutants exhibit decreased virulence in rat pups, demonstrating the utility of the model to evaluate the impact of specific genes in disease pathogenesis. Our findings highlight the contribution of lipases to the virulence of C. albicans and C. parapsilosis and provide a new system to study the increased susceptibility of neonates to Candida infections.