Attributable Mortality and Excess Length of Stay associated with Third-Generation Cephalosporin Resistant Enterobacterales Bloodstream Infections - a prospective cohort study in Suva, Fiji

OBJECTIVES

There are scant primary clinical data on antimicrobial resistance (AMR) burden from low- and middle-income countries (LMICs). We adapted recent World Health Organization methodology to measure the impact of third-generation cephalosporin resistance (3GC-R) on mortality and excess length of hospital stay in Fiji.

METHODS

We conducted a prospective cohort study of inpatients with Enterobacterales bloodstream infections (BSIs) at Colonial War Memorial Hospital, Suva. We used cause-specific Cox proportional hazards models to estimate the effect of 3GC-R on the daily risk (hazard) of in-hospital mortality and being discharged alive (competing risks), and multistate modelling to estimate the excess length of hospital stay.

RESULTS

From July 2020 to February 2021 we identified 162 consecutive Enterobacterales BSIs, 3GC-R was present in 66 (40.7%). Crude mortality for patients with 3GC-susceptible and 3GC-R BSIs was 16.7% (16/96) and 30.3% (20/66), respectively. 3GC-R was not associated with the in-hospital mortality hazard rate (adjusted hazard ratio (aHR) 1.13, 95% CI 0.51-2.53) or being discharged alive (aHR 0.99, 95% CI 0.65-1.50), whereas Charlson comorbidity index score (aHR 1.62, 95% CI 1.36-1.93) and Pitt bacteraemia score (aHR 3.57, 95% CI 1.31-9.71) were both associated with an increased hazard rate of in-hospital mortality. 3GC-R was associated with an increased length of stay of 2.6 days (95% CI 2.5-2.8). 3GC-R was more common among hospital-associated infections, but genomics did not identify clonal transmission.

CONCLUSION

Patients with Enterobacterales BSIs in Fiji had high mortality. There were high rates of 3GC-R, which was associated with increased hospital length of stay but not with in-hospital mortality.

Variation in Newborn Skincare Policies Across United States Maternity Hospitals

OBJECTIVE

Newborn skincare influences levels of beneficial factors from vernix and vaginal secretions but also the emergence of potential skin pathogens. However, evidence-based national guidelines for newborn skincare do not exist, and actual hospital practices for newborn skincare have not been described. In this study, we test the hypothesis that US maternity hospitals follow differing policies with regard to newborn skincare.

METHODS

A 16-question survey querying skin care practices was distributed to nursery medical directors at the 109 US hospital members of the Better Outcomes through Research for Newborns network. Data from free text responses were coded by 2 study personnel. Survey responses were analyzed by using descriptive statistics and compared by region of the United States.

RESULTS

Delaying the first newborn bath by at least 6 hours is a practice followed by 87% of US hospitals surveyed. Discharging newborns without a bath was reported in 10% of hospitals and was more common for newborns born in nonacademic centers and on the West Coast. Procedures and products used for newborn skincare varied significantly. Parental education on tub immersion and soap use was also inconsistent and potentially contradictory between providers. Evidence cited by hospitals in forming their policies is scant.

CONCLUSION

In this study, we identify similar and strikingly different newborn skincare policies across a national network of US maternity hospitals. Research is needed to identify effects of differing skincare routines on skin integrity, infection rates, and childhood health outcomes to improve the evidence base for the care of newborn skin.

Apple cider vinegar soaks [0.5%] as a treatment for atopic dermatitis do not improve skin barrier integrity

BACKGROUND/OBJECTIVES

Atopic dermatitis (AD) is a common chronic inflammatory skin condition associated with high transepidermal water loss, high skin pH, and Staphylococcus aureus skin colonization. The treatment of AD with bath additives remains highly debated. Recent evidence suggests that dilute apple cider vinegar (ACV) may improve skin barrier integrity in AD, but its safety and efficacy are not well studied. This pilot split-arm study analyzed the effect of dilute apple cider vinegar soaks on skin barrier integrity in patients with atopic dermatitis as measured by skin transepidermal water loss and skin pH.

METHODS

A total of 22 subjects (11 AD and 11 healthy controls) were enrolled. Subjects soaked both of their forearms for 14 days, with one arm in dilute ACV (0.5% acetic acid) and the other in water 10 minutes daily. Transepidermal water loss and pH were measured pre- and post-treatment.

RESULTS

In both groups, transepidermal water loss increased and pH decreased at 0 minutes post-ACV treatment, but these effects were not sustained at 60 minutes. In total, 72.7% (16/22) of subjects reported mild side effects from ACV with improvement after discontinuing the soaks.

CONCLUSIONS

Dilute ACV soaks have no significant effect on skin barrier integrity but caused skin irritation in a majority of subjects. Study limitations include analysis of a single brand, dilution, and application of ACV. Future studies are needed to explore whether lower concentrations of ACV soaks or other applications such as a leave-on acidic ointment could improve skin barrier integrity in a safe, nonirritating way.

Lung Lavage Granulocyte Patterns and Clinical Phenotypes in Children with Severe, Therapy-Resistant Asthma

BACKGROUND

Children with severe asthma have frequent exacerbations despite guidelines-based treatment with high-dose corticosteroids. The importance of refractory lung inflammation and infectious species as factors contributing to poorly controlled asthma in children is poorly understood.

OBJECTIVE

To identify prevalent granulocyte patterns and potential pathogens as targets for revised treatment, 126 children with severe asthma underwent clinically indicated bronchoscopy.

METHODS

Diagnostic tests included bronchoalveolar lavage (BAL) for cell count and differential, bacterial and viral studies, spirometry, and measurements of blood eosinophils, total IgE, and allergen-specific IgE. Outcomes were compared among 4 BAL granulocyte patterns.

RESULTS

Pauci-granulocytic BAL was the most prevalent granulocyte category (52%), and children with pauci-granulocytic BAL had less postbronchodilator airflow limitation, less blood eosinophilia, and less detection of BAL enterovirus compared with children with mixed granulocytic BAL. Children with isolated neutrophilia BAL were differentiated by less blood eosinophilia than those with mixed granulocytic BAL, but greater prevalence of potential bacterial pathogens compared with those with pauci-granulocytic BAL. Children with isolated eosinophilia BAL had features similar to those with mixed granulocytic BAL. Children with mixed granulocytic BAL took more maintenance prednisone, and had greater blood eosinophilia and allergen sensitization compared with those with pauci-granulocytic BAL.

CONCLUSIONS

In children with severe, therapy-resistant asthma, BAL granulocyte patterns and infectious species are associated with novel phenotypic features that can inform pathway-specific revisions in treatment. In 32% of children evaluated, BAL revealed corticosteroid-refractory eosinophilic infiltration amenable to anti-T_H2 biological therapies, and in 12%, a treatable bacterial pathogen.

TH1 signatures are present in the lower airways of children with severe asthma, regardless of allergic status

BACKGROUND

The pathogenesis of severe asthma in childhood remains poorly understood.

OBJECTIVE

We sought to construct the immunologic landscape in the airways of children with severe asthma.

METHODS

Comprehensive analysis of multiple cell types and mediators was performed by using flow cytometry and a multiplex assay with bronchoalveolar lavage (BAL) specimens (n = 68) from 52 highly characterized allergic and nonallergic children (0.5-17 years) with severe treatment-refractory asthma. Multiple relationships were tested by using linear mixed-effects modeling.

RESULTS

Memory CCR5⁺ T_H1 cells were enriched in BAL fluid versus blood, and pathogenic respiratory viruses and bacteria were readily detected. IFN-γ⁺IL-17⁺ and IFN-γ^-IL-17⁺ subsets constituted secondary T_H types, and BAL fluid CD8⁺ T cells were almost exclusively IFN-γ⁺. The T_H17-associated mediators IL-23 and macrophage inflammatory protein 3α/CCL20 were highly expressed. Despite low T_H2 numbers, T_H2 cytokines were detected, and T_H2 skewing correlated with total IgE levels. Type 2 innate lymphoid cells and basophils were scarce in BAL fluid. Levels of IL-5, IL-33, and IL-28A/IFN-λ2 were increased in multisensitized children and correlated with IgE levels to dust mite, ryegrass, and fungi but not cat, ragweed, or food sources. Additionally, levels of IL-5, but no other cytokine, increased with age and correlated with eosinophil numbers in BAL fluid and blood. Both plasmacytoid and IgE⁺FcεRI⁺ myeloid dendritic cells were present in BAL fluid.

CONCLUSIONS

The lower airways of children with severe asthma display a dominant T_H1 signature and atypical cytokine profiles that link to allergic status. Our findings deviate from established paradigms and warrant further assessment of the pathogenicity of T_H1 cells in patients with severe asthma.

The Skin as a Route of Allergen Exposure: Part II. Allergens and Role of the Microbiome and Environmental Exposures

PURPOSE OF REVIEW

This second part of the article aims to highlight recent contributions in the literature that enhance our understanding of the cutaneous immune response to allergen.

RECENT FINDINGS

Several properties of allergens facilitate barrier disruption and cutaneous sensitization. There is a strong epidemiologic relationship between the microbiome, both the gut and skin, and atopic dermatitis (AD). The mechanisms connecting these two entities remain enigmatic; however, recent murine models show that commensal skin bacteria play an active role in supporting skin barrier homeostasis and defense against microbial penetration. Likewise, the association between the lack of colonization with Staph species and AD development suggests a potentially functional role for these organisms in regulating the skin barrier and response to environmental allergens. In undisrupted skin, evidence suggests that the cutaneous route may promote allergen tolerance. Properties of environmental allergens and commensal bacteria add to the complex landscape of skin immunity. Further investigation is needed to elucidate how these properties regulate the cutaneous immune response to allergen.

A comparison of seasonal trends in asthma exacerbations among children from geographic regions with different climates

BACKGROUND

The fall peak in childhood asthma exacerbations is thought to be related to an increase in viral infections and allergen exposure when children return to school. Whether the seasonality of asthma attacks among children from different geographic regions follows similar trends is unclear.

OBJECTIVE

To compare seasonal trends in asthma exacerbations among school-age children who lived in different geographic locations, with different climates, within the United States.

METHODS

Hospital billing data bases were examined to determine the monthly number of school-age children who were hospitalized or treated in the emergency department (ED) for asthma exacerbations. Data from four cities within three states were compared. Climate data were obtained from archives of the National Climate Data Center, U.S. Department of Commerce.

RESULTS

An annual peak in asthma exacerbations was observed during the fall months (September through November) among children who lived in Charlottesville, Virginia, as well as throughout the state of Virginia. An increase in exacerbations, which peaked in November, was observed for exacerbations among children who lived in Tucson, Arizona, and Yuma, Arizona. In contrast, exacerbations among children from New Orleans, Louisiana, increased in September but remained elevated throughout the school year. Although there was annual variation in the frequency of exacerbations over time, the seasonal patterns observed remained similar within the locations from year to year. A nadir in the frequency of attacks was observed during the summer months in all the locations.

CONCLUSION

Seasonal peaks for asthma exacerbations varied among the children who lived in geographic locations with different climates, and were not restricted to the beginning of the school year.

Analysis of cytokine production by peanut-reactive T cells identifies residual Th2 effectors in highly allergic children who received peanut oral immunotherapy

BACKGROUND

Only limited evidence is available regarding the cytokine repertoire of effector T cells associated with peanut allergy, and how these responses relate to IgE antibodies to peanut components.

OBJECTIVE

To interrogate T cell effector cytokine populations induced by Ara h 1 and Ara h 2 among peanut allergic (PA) children in the context of IgE and to evaluate their modulation during oral immunotherapy (OIT).

METHODS

Peanut-reactive effector T cells were analysed in conjunction with specific IgE profiles in PA children using intracellular staining and multiplex assay. Cytokine-expressing T cell subpopulations were visualized using SPICE.

RESULTS

Ara h 2 dominated the antibody response to peanut as judged by prevalence and quantity among a cohort of children with IgE to peanut. High IgE (> 15 kU(A)/L) was almost exclusively associated with dual sensitization to Ara h 1 and Ara h 2 and was age independent. Among PA children, IL-4-biased responses to both major allergens were induced, regardless of whether IgE antibodies to Ara h 1 were present. Among subjects receiving OIT in whom high IgE was maintained, Th2 reactivity to peanut components persisted despite clinical desensitization and modulation of allergen-specific immune parameters including augmented specific IgG4 antibodies, Th1 skewing and enhanced IL-10. The complexity of cytokine-positive subpopulations within peanut-reactive IL-4(+) and IFN-γ(+) T cells was similar to that observed in those who received no OIT, but was modified with extended therapy. Nonetheless, high Foxp3 expression was a distinguishing feature of peanut-reactive IL-4(+) T cells irrespective of OIT, and a correlate of their ability to secrete type 2 cytokines.

CONCLUSION

Although total numbers of peanut-reactive IL-4(+) and IFN-γ(+) T cells are modulated by OIT in highly allergic children, complex T cell populations with pathogenic potential persist in the presence of recognized immune markers of successful immunotherapy.

Sensitization to food and inhalant allergens in relation to age and wheeze among children with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is common in children; however, persistence of AD with or without asthma is less common. Longitudinal studies remain limited in their ability to characterize how IgE antibody responses evolve in AD, and their relationship with asthma.

OBJECTIVE

To use a cross-sectional study design of children with active AD to analyse age-related differences in IgE antibodies and relation to wheeze.

METHODS

IgE antibodies to food and inhalant allergens were measured in children with active AD (5 months to 15 years of age, n = 66), with and without history of wheeze.

RESULTS

Whereas IgE antibodies to foods persisted at a similar prevalence and titre throughout childhood, IgE antibodies to all aeroallergens rose sharply into adolescence. From birth, the chance of sensitization for any aeroallergen increased for each 12-month increment in age (OR ≥ 1.21, P < 0.01), with the largest effect observed for dust mite (OR = 1.56, P < 0.001). A steeper age-related rise in IgE antibody titre to dust mite, but no other allergen was associated with more severe disease. Despite this, sensitization to cat was more strongly associated with wheeze (OR = 4.5, P < 0.01), and linked to Fel d 1 and Fel d 4, but not Fel d 2. Comparison of cat allergic children with AD to those without, revealed higher IgE levels to Fel d 2 and Fel d 4 (P < 0.05), but not Fel d 1.

CONCLUSIONS AND CLINICAL RELEVANCE

Differences in sensitization to cat and dust mite among young children with AD may aid in identifying those at increased risk for disease progression and development of asthma. Early sensitization to cat and risk for wheeze among children with AD may be linked to an increased risk for sensitization to a broader spectrum of allergen components from early life. Collectively, our findings argue for early intervention strategies designed to mitigate skin inflammation in children with AD.

The role of regulatory T cells in atopic dermatitis

Regulatory T (T(reg)) cells play a pivotal role in immune suppression and are integral to the control of allergic responses. The chronic inflammatory skin condition atopic dermatitis (AD) is severest in patients who are sensitized to allergens from diverse sources including foods, pollens and animal danders, as well as skin-colonizing organisms. These individuals typically present with eczematous skin eruptions in early childhood, and evolution of the disease is thought to reflect an underlying dysregulated T-cell response to allergens that manifests as a Th2 response. Studying T(reg) cells in the context of AD from infancy into adulthood could yield insight into their role in disease pathogenesis and reveal new strategies for exploiting these cells for therapeutic purposes. Such studies are challenging in humans owing to the heterogeneous nature of T(reg) cells, lack of a reliable surface marker, and the paucity of knowledge surrounding the emergence of specialized T cells in early life. Moreover, the blurred distinction between activated effector T cells and T(reg) cells further complicates studies in the context of inflammatory disorders such as AD. There is emerging evidence to suggest that T(reg) cells can convert to Th2 cells and that this pathway is bidirectional. This phenomenon may be a double-edged sword with important implications not only for subverting T(reg) cells in disease, but also for potential treatments designed to amplify these cells in order to suppress the allergic inflammatory cascade in AD.

Novel cytokines and cytokine-producing T cells in allergic disorders

Allergic diseases reflect various pathways of T lymphocyte inflammation and largely comprise T helper (Th) 2-associated processes. Recent investigations have identified pathways involved in promoting Th2 responses. Additionally, novel T-cell subtypes, each with its own distinct cytokine profile, contribute to the heterogeneous presentations of allergic diseases. This article focuses on recent developments including novel effector (nuocytes, Th9, and Th22) and regulatory T-cell (Treg) families of lymphocytes as well as cytokines that are central in driving Th2 differentiation (interleukin [IL]-4, IL-9, IL-25, thymic stromal lymphopoietin [TSLP], and IL-33). Recent literature and investigations were reviewed. Unregulated IL-25, TSLP, and IL-33 activity results in activation of Th2 cells, mast cells, dendritic cells, eosinophils, and basophils, leading to inflammatory processes that define allergic disease. As such, these cytokines are central mediators capable of instigating the inflammatory processes responsible for allergen-mediated diseases. The previous paradigm of Th1/Th2 imbalance driving allergic disease is expanded by identification of novel T helper families (nuocytes, Th9, Th17, and Th22) with their signature cytokines, which provide alterative avenues for investigation of neutrophil-predominant asthma and other heterogeneous presentations of allergic diseases. IL-25, TSLP, and IL-33 are attractive targets for therapeutics designed to ameliorate Th2-mediated diseases such as allergic rhinitis and asthma. Moreover, the ability to delineate novel regulatory and effector T-cell lineages among CD4(+) T cells challenges the Th1/Th2 paradigm of allergic disease and invites further avenues of investigation into the role of these cells in allergic disease.

Application of isolated hepatocytes to studies of drug metabolism in large food animals

A definitive hazard assessment of xenobiotics translocated through food animals into edible products such as meat or milk requires a complete analysis of metabolism in food animals. However, large animal metabolism studies present many experimental difficulties. None of several in vitro alternatives such as subcellular fractions has been established as an acceptable predictor of in vivo metabolism. The feasibility of using isolated hepatocytes to predict the metabolism of xenobiotics, both quantitatively and qualitatively, in large ruminant animals (e.g. cattle) is being studied in our laboratory. A procedure was developed for isolating hepatocytes aseptically from the caudate process of the liver which was obtained surgically from 100-125 kg calves. A modified two-step vascular perfusion procedure provides hepatocyte suspensions that are typically greater than or equal to 85% viable and greater than or equal to 1 X 10(7) viable hepatocytes/g of liver (wet wt). Xenobiotic metabolism has been evaluated in suspensions and primary cultures using aldrin epoxidation, ethoxycoumarin O-deethylation, and 7-hydroxycoumarin glucuronidation and sulfation. Metabolic activities are relatively short-lived in suspensions less than or equal to 4 h, but quite stable up to 10 h when cultured on collagen-coated plates in chemically defined medium. Bovine hepatocytes behave similarly in culture to rodent hepatocytes. Although primary culturing of hepatocytes is more difficult than suspensions, primarily due to the asepsis requirements, it is the method of choice for xenobiotic metabolism determinations in isolated hepatocytes of cattle.

Interlobular distribution of hepatic xenobiotic-metabolizing enzyme activities in cattle, goats and sheep

Microsomal and cytosolic enzymes that metabolize xenobiotics were measured in composite samples representing entire livers and in samples from three lobes, using livers of cattle, goats and sheep. Within individual species, concentrations of cytochrome P-450 and b5 and activities of NADPH cytochrome c reductase, aldrin epoxidase, aminopyrine N-demethylase, ethoxycoumarin O-deethylase, microsomal and cytosolic stilbene oxide (epoxide) hydrolase and glutathione S-transferase were not different (P greater than .05) among the various hepatic lobes. Among species, several activities differed (P less than .05), with cattle livers generally having lower values than sheep or goats.

Xenobiotic metabolism in suspensions and primary cultures of isolated hepatocytes prepared from the caudate process of bovine liver

Isolated hepatocytes were prepared from 100- to 125-kg Holstein male calves (n = 10) by perfusion of the caudate process of the caudate lobe of the liver. The 11th or 12th rib on the right side was resected to provide exposure of the caudate process. Complete postsurgical recovery of the donor from partial lobectomy was confirmed by growth data and serum chemical and hematologic criteria. Hepatocytes were isolated under aseptic conditions, using a 2-step collagenase vascular perfusion procedure. Hepatocyte preparations averaged 85% viability, and the yield averaged 1.2 X 10(7) viable hepatocytes/g of (wet weight) liver. Morphologic characteristics of hepatocytes examined under light and scanning electron microscopy were considered normal, except for occasional surface blebs. Freshly isolated hepatocytes in suspension rapidly decreased in viability and xenobiotic metabolizing capacity (aldrin epoxidation and ethoxycoumarin 0-deethylation and 7-hydroxycoumarin glucuronidation and sulfation), and hepatocytes surviving the initial 2 to 3 hours appeared to undergo repair. As an alternative, primary monolayer cultures on collagen-coated plates were evaluated. Hepatocytes attached to the collagen surface within 4 hours and appeared flattened by 12 hours. Although metabolic activity decreased about 30% over 8 hours in culture, the pattern of ethoxycoumarin metabolites was relatively constant. It was not determined to what extent the apparent loss of metabolic capacity was caused by hepatocyte detachment from the collagen surface. Although complicated by the requirement for asepsis, primary cultures were superior to suspensions for xenobiotic metabolism studies in cattle.

Biological and induction effects of phenobarbital and 3-methylcholanthrene in mink (Mustela vison)

Mink were injected (ip) daily with 20 mg/kg of 3-methylcholanthrene (MC) or 40 mg/kg of phenobarbital (PB) for 3 days and killed 48 hr after the last injection. The duration of anesthetic action of PB increased after each injection. MC-treated mink became anorexic and lost substantial body weight. PB caused enlargement of liver and lungs, whereas MC caused liver atrophy. No major treatment-related morphologic changes including amount of endoplasmic reticulum (ER) in liver were revealed by electron microscopic examination. Microsomal protein content was not increased and NADPH cytochrome P-450 reductase was not induced in liver by either PB or MC. Cytochrome P-450 (448) was increased 3.2-fold by PB and 2.5-fold by MC. Cytochrome b5 was increased 2.3-fold by MC but was not affected by PB. Aminopyrine N-demethylase was enhanced 5.1-fold in activity by PB whereas hexobarbital hydroxylase was not induced. MC-treatment moderately increased the activities of benzo(a)pyrene hydroxylase (1.7-fold) and ethoxyresorufin O-deethylase (2.1-fold) but had no effect on ethoxycoumarin O-deethylase. The most distinctive features of the mink revealed by this study are a) lack of PB induction of the ER, microsomal protein content, NADPH-cytochrome P-450 reductase, and hexobarbital hydroxylase, and b) lack of MC induction of cytochrome P-448-associated mixed function oxidases that are known to be highly responsive to MC in other species.