Serum procalcitonin as a diagnostic biomarker in dogs with bacterial respiratory diseases

BACKGROUND

Procalcitonin (PCT) is a useful biomarker in humans in the identification of bacterial respiratory infections.

OBJECTIVES

The aim of this study was to investigate the utility of serum PCT measurements as a diagnostic biomarker in canine bacterial lower respiratory tract diseases.

METHODS

PCT concentrations were measured in serum samples with an ELISA method previously validated for dogs. All dogs underwent thorough clinical examinations, and the diagnosis of respiratory disease was based on clinical and laboratory findings, diagnostic imaging, as well as cytology and bacterial culture of respiratory samples. PCT concentrations between different cohorts of dogs were compared with an ANOVA-model.

RESULTS

Sixty-two privately owned dogs with respiratory diseases, 25 with bacterial pneumonia (BP), 17 with bacterial bronchitis caused by Bordetella bronchiseptica (BB), and 20 with chronic bronchitis (CB) as well as 44 healthy controls were included in the study. Serum PCT concentrations in dogs with bacterial respiratory diseases (BP mean 51.8 ng/L ± standard deviation [SD] 40.6 ng/L and BB mean 61.4 ng/L ± SD 35.3 ng/L) were not significantly different when compared with dogs with a non-bacterial respiratory disease (CB mean 89.7 ± SD 73.5 ng/L) or healthy dogs (mean 51.0 ng/L ± SD 37.5 ng/L, p > .05 in all comparisons).

CONCLUSIONS

These results indicate that despite being a valuable diagnostic, prognostic, and follow-up marker in humans with pneumonia, serum PCT concentrations are not elevated in dogs with bacterial respiratory diseases and, therefore, cannot be used as a diagnostic biomarker in dogs.

Diagnostic value of coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage

BACKGROUND

Stroke is the second reason for global deaths and a major reason for disabilities.

OBJECTIVE

To unravel the clinical value of the coagulation index and serum inflammatory cytokines in hemorrhagic stroke patients with pulmonary infection in the sequelae stage.

METHODS

Altogether, 130 hemorrhagic stroke patients who received treatment in Hebei General Hospital from April 2019 to December 2020 were selected. Patients were classified into the infection group (n= 65) and non-infection group (n= 65) according to whether they had a pulmonary infection in the sequelae stage of hemorrhagic stroke. Levels of coagulation index and serum inflammatory cytokines of patients in two groups were compared. Multiple linear regression analysis was used to analyze pulmonary infection-related factors of hemorrhagic stroke patients. The diagnostic value of the coagulation index and serum inflammatory cytokines in pulmonary infection was analyzed by the receiver operating characteristic (ROC) curve.

RESULTS

Prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), D-dimer (D-D), platelet (PLT) related to coagulation function levels and interleukin 1β (IL-1β), interleukin 17 (IL-17) related to serum inflammatory cytokines levels of patients in the infection group were higher than those in non-infection groups (p< 0.05). Multiple linear regression analysis uncovered that FIB, D-D, PLT, and IL-17 were influencing factors of pulmonary infection in the sequelae of patients with hemorrhagic stroke (p< 0.05). Area under the curve (AUC) values of pulmonary infection in the sequelae stage of patients with hemorrhagic stroke diagnosed by FIB, D-D, PLT, and IL-17 were 0.823, 0.758, 0.660, and 0.755, respectively.

CONCLUSION

FIB, D-D, PLT, and IL-17 levels could be used for pulmonary infection diagnosis in the sequelae stage of hemorrhagic stroke patients.

Efficacy and Safety of an Ad26.RSV.preF-RSV preF Protein Vaccine in Older Adults

BACKGROUND

Respiratory syncytial virus (RSV) can cause serious lower respiratory tract disease in older adults, but no licensed RSV vaccine currently exists. An adenovirus serotype 26 RSV vector encoding a prefusion F (preF) protein (Ad26.RSV.preF) in combination with RSV preF protein was previously shown to elicit humoral and cellular immunogenicity.

METHODS

We conducted a randomized, double-blind, placebo-controlled, phase 2b, proof-of-concept trial to evaluate the efficacy, immunogenicity, and safety of an Ad26.RSV.preF-RSV preF protein vaccine. Adults who were 65 years of age or older were randomly assigned in a 1:1 ratio to receive vaccine or placebo. The primary end point was the first occurrence of RSV-mediated lower respiratory tract disease that met one of three case definitions: three or more symptoms of lower respiratory tract infection (definition 1), two or more symptoms of lower respiratory tract infection (definition 2), and either two or more symptoms of lower respiratory tract infection or one or more symptoms of lower respiratory tract infection plus at least one systemic symptom (definition 3).

RESULTS

Overall, 5782 participants were enrolled and received an injection. RSV-mediated lower respiratory tract disease meeting case definitions 1, 2, and 3 occurred in 6, 10, and 13 vaccine recipients and in 30, 40, and 43 placebo recipients, respectively. Vaccine efficacy was 80.0% (94.2% confidence interval [CI], 52.2 to 92.9), 75.0% (94.2% CI, 50.1 to 88.5), and 69.8% (94.2% CI, 43.7 to 84.7) for case definitions 1, 2, and 3, respectively. After vaccination, RSV A2 neutralizing antibody titers increased by a factor of 12.1 from baseline to day 15, a finding consistent with other immunogenicity measures. Percentages of participants with solicited local and systemic adverse events were higher in the vaccine group than in the placebo group (local, 37.9% vs. 8.4%; systemic, 41.4% vs. 16.4%); most adverse events were mild to moderate in severity. The frequency of serious adverse events was similar in the vaccine group and the placebo group (4.6% and 4.7%, respectively).

CONCLUSIONS

In adults 65 years of age or older, Ad26.RSV.preF-RSV preF protein vaccine was immunogenic and prevented RSV-mediated lower respiratory tract disease. (Funded by Janssen Vaccines and Prevention; CYPRESS ClinicalTrials.gov number, NCT03982199.).

C-reactive protein or procalcitonin combined with rhinorrhea for discrimination of viral from bacterial infections in hospitalized adults in non-intensive care units with lower respiratory tract infections

BACKGROUND

Whether procalcitonin (PCT) or C-reactive protein (CRP) combined with certain clinical characteristics can better distinguish viral from bacterial infections remains unclear. The aim of the study was to assess the ability of PCT or CRP combined with clinical characteristics to distinguish between viral and bacterial infections in hospitalized non-intensive care unit (ICU) adults with lower respiratory tract infection (LRTI).

METHODS

This was a post-hoc analysis of a randomized clinical trial previously conducted among LRTI patients. The ability of PCT, CRP and PCT or CRP combined with clinical symptoms to discriminate between viral and bacterial infection were assessed by portraying receiver operating characteristic (ROC) curves among patients with only a viral or a typical bacterial infection.

RESULTS

In total, 209 infected patients (viral 69%, bacterial 31%) were included in the study. When using CRP or PCT to discriminate between viral and bacterial LRTI, the optimal cut-off points were 22 mg/L and 0.18 ng/mL, respectively. When the optimal cut-off for CRP (≤ 22 mg/L) or PCT (≤ 0.18 ng/mL) combined with rhinorrhea was used to discriminate viral from bacterial LRTI, the AUCs were 0.81 (95% CI: 0.75-0.87) and 0.80 (95% CI: 0.74-0.86), which was statistically significantly better than when CRP or PCT used alone (p < 0.001). When CRP ≤ 22 mg/L, PCT ≤ 0.18 ng/mL and rhinorrhea were combined, the AUC was 0.86 (95% CI: 0.80-0.91), which was statistically significantly higher than when CRP (≤ 22 mg/L) or PCT (≤ 0.18 ng/mL) was combined with rhinorrhea (p = 0.011 and p = 0.021).

CONCLUSIONS

Either CRP ≤ 22 mg/L or PCT ≤ 0.18 ng/mL combined with rhinorrhea could help distinguish viral from bacterial infections in hospitalized non-ICU adults with LRTI. When rhinorrhea was combined together, discrimination ability was further improved.

Vitamin D and upper respiratory tract infections in young active males exposed to cold environments

INTRODUCTION AND OBJECTIVE

Performing indoor and outdoor work in cold environments may result in various adverse effects on human health and may lead to increased risk of respiratory infection. The aim of this study was to determine the relation of vitamin D status to secretory immunoglobulin A concentration, leucocyte counts, cytokine concentrations and incidence of upper respiratory tract infection (URTI) episodes in young active men during an autumn-winter period.

MATERIAL AND METHODS

The effect of work in a cold microclimate was studied among 23 young active male ice hockey players during a 19-week study period. Blood and saliva samples were collected 7 times during the study period. Incidence of URTI was evaluated using WURSS 21. White blood cell, neutrophil, lymphocyte, monocyte, eosinophil and basophil counts, concentrations of 25(OH)D, C-reactive protein, cortisol, IL-1ra, IL-10, IL-1β and immunoglobulins A, M and G, were determined in the blood. Secretory immunoglobulin A, A1 and A2 and cortisol were analysed in saliva. Spearman's correlations were used to evaluate relationships between initial or final 25(OH)D concentration and URTI incidence, as well as the immune and endocrine markers. Differences in URTI episodes, immune and endocrine parameters between sufficient ( ≥20 ng·ml ^-1) and deficient (<20 ng ·ml ^-1) vitamin D status groups were compared with the Mann-Whitney test.

RESULTS

There were no statistically significant correlations between mucosal and blood markers or URTI incidence and initial and final 25(OH)D concentrations. Immune, endocrine and URTI variables did not differ between deficient and sufficient vitamin D status groups.

CONCLUSIONS

25(OH)D concentration has no impact on mucosal and systemic immunity, nor on URTI episodes.

Infection is associated with elevated serum concentrations of antipsychotic drugs

We aimed to investigate the effects of infection on serum concentrations of different antipsychotics in inpatients with respiratory tract infections treated with psychiatric drugs, including risperidone, clozapine, quetiapine, and aripiprazole. All patients underwent therapeutic drug monitoring (TDM) and routine blood tests during infection and noninfection periods. The Wilcoxon signed-rank test was used to analyze intra-individual differences in dose-corrected serum concentrations (C/D) levels in infection and noninfection periods. To study the effects of infection intensity on drug concentrations, white blood cells (WBCs) parameters and C/D levels were analyzed by Spearman's correlation analysis using all samples. The median C/D levels of risperidone (risperidone + 9-OH, n = 36) and clozapine (n = 42) were significantly higher (P < 0.001), whereas the median C/D levels of quetiapine (n = 21) and aripiprazole (n = 13) were slightly significantly higher (P < 0.01) in infection than in noninfection period. A significant positive association between C/D levels and WBC parameters was observed for risperidone, clozapine, and quetiapine. These results indicated reduced clearance of all drugs evaluated, especially clozapine and risperidone, due to infection. Therefore, during infection in patients receiving risperidone, clozapine, quetiapine, or aripiprazole, TDM should be performed to minimize the possible adverse effects associated with elevated drug concentrations.

Identifying COVID-19-Specific Transcriptomic Biomarkers with Machine Learning Methods

COVID-19, a severe respiratory disease caused by a new type of coronavirus SARS-CoV-2, has been spreading all over the world. Patients infected with SARS-CoV-2 may have no pathogenic symptoms, i.e., presymptomatic patients and asymptomatic patients. Both patients could further spread the virus to other susceptible people, thereby making the control of COVID-19 difficult. The two major challenges for COVID-19 diagnosis at present are as follows: (1) patients could share similar symptoms with other respiratory infections, and (2) patients may not have any symptoms but could still spread the virus. Therefore, new biomarkers at different omics levels are required for the large-scale screening and diagnosis of COVID-19. Although some initial analyses could identify a group of candidate gene biomarkers for COVID-19, the previous work still could not identify biomarkers capable for clinical use in COVID-19, which requires disease-specific diagnosis compared with other multiple infectious diseases. As an extension of the previous study, optimized machine learning models were applied in the present study to identify some specific qualitative host biomarkers associated with COVID-19 infection on the basis of a publicly released transcriptomic dataset, which included healthy controls and patients with bacterial infection, influenza, COVID-19, and other kinds of coronavirus. This dataset was first analysed by Boruta, Max-Relevance and Min-Redundancy feature selection methods one by one, resulting in a feature list. This list was fed into the incremental feature selection method, incorporating one of the classification algorithms to extract essential biomarkers and build efficient classifiers and classification rules. The capacity of these findings to distinguish COVID-19 with other similar respiratory infectious diseases at the transcriptomic level was also validated, which may improve the efficacy and accuracy of COVID-19 diagnosis.

Update on Infections in Primary Antibody Deficiencies

Bacterial respiratory tract infections are the hallmark of primary antibody deficiencies (PADs). Because they are also among the most common infections in healthy individuals, PADs are usually overlooked in these patients. Careful evaluation of the history, including frequency, chronicity, and presence of other infections, would help suspect PADs. This review will focus on infections in relatively common PADs, discussing diagnostic challenges, and some management strategies to prevent infections.

INEXAS: A Phase 2 Randomized Trial of On-demand Inhaled Interferon Beta-1a in Severe Asthmatics

BACKGROUND

Upper respiratory tract infections (URTIs) are important triggers for asthma exacerbations. We hypothesized that inhalation of the anti-viral cytokine, interferon (IFN)-β, during URTI, could prevent these exacerbations.

OBJECTIVE

To evaluate the efficacy of on-demand inhaled IFN-β1a (AZD9412) to prevent severe asthma exacerbations following symptomatic URTI.

METHODS

This was a randomized, double-blind, placebo-controlled trial in which patients with severe asthma (GINA 4-5; n = 121) reporting URTI symptoms were randomized to 14 days of once-daily nebulized AZD9412 or placebo. The primary endpoint was severe exacerbations during treatment. Secondary endpoints included 6-item asthma control questionnaire (ACQ-6) and lung function. Exploratory biomarkers included IFN-response markers in serum and sputum, blood leucocyte counts and serum inflammatory cytokines.

RESULTS

Following a pre-planned interim analysis, the trial was terminated early due to an unexpectedly low exacerbation rate. Asthma worsenings were generally mild and tended to peak at randomization, possibly contributing to the lack of benefit of AZD9412 on other asthma endpoints. Numerically, AZD9412 did not reduce severe exacerbation rate, ACQ-6, asthma symptom scores or reliever medication use. AZD9412 improved lung function (morning peak expiratory flow; mPEF) by 19.7 L/min. Exploratory post hoc analyses indicated a greater mPEF improvement by AZD9412 in patients with high blood eosinophils (>0.3 × 109 /L) at screening and low serum interleukin-18 relative change at pre-treatment baseline. Pharmacodynamic effect of AZD9412 was confirmed using IFN-response markers.

CONCLUSIONS & CLINICAL RELEVANCE

Colds did not have the impact on asthma patients that was expected and, due to the low exacerbation rate, the trial was stopped early. On-demand AZD9412 treatment did not numerically reduce the number of exacerbations, but did attenuate URTI-induced worsening of mPEF. Severe asthma patients with high blood eosinophils or low serum interleukin-18 response are potential subgroups for further investigation of inhaled IFN-β1a.

Case Study: Prolonged Infectious SARS-CoV-2 Shedding from an Asymptomatic Immunocompromised Individual with Cancer

Long-term severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shedding was observed from the upper respiratory tract of a female immunocompromised individual with chronic lymphocytic leukemia and acquired hypogammaglobulinemia. Shedding of infectious SARS-CoV-2 was observed up to 70 days, and of genomic and subgenomic RNA up to 105 days, after initial diagnosis. The infection was not cleared after the first treatment with convalescent plasma, suggesting a limited effect on SARS-CoV-2 in the upper respiratory tract of this individual. Several weeks after a second convalescent plasma transfusion, SARS-CoV-2 RNA was no longer detected. We observed marked within-host genomic evolution of SARS-CoV-2 with continuous turnover of dominant viral variants. However, replication kinetics in Vero E6 cells and primary human alveolar epithelial tissues were not affected. Our data indicate that certain immunocompromised individuals may shed infectious virus longer than previously recognized. Detection of subgenomic RNA is recommended in persistently SARS-CoV-2-positive individuals as a proxy for shedding of infectious virus.

A blood-based host gene expression assay for early detection of respiratory viral infection: an index-cluster prospective cohort study

Background

Early and accurate identification of individuals with viral infections is crucial for clinical management and public health interventions. We aimed to assess the ability of transcriptomic biomarkers to identify naturally acquired respiratory viral infection before typical symptoms are present.

Methods

In this index-cluster study, we prospectively recruited a cohort of undergraduate students (aged 18–25 years) at Duke University (Durham, NC, USA) over a period of 5 academic years. To identify index cases, we monitored students for the entire academic year, for the presence and severity of eight symptoms of respiratory tract infection using a daily web-based survey, with symptoms rated on a scale of 0–4. Index cases were defined as individuals who reported a 6-point increase in cumulative daily symptom score. Suspected index cases were visited by study staff to confirm the presence of reported symptoms of illness and to collect biospecimen samples. We then identified clusters of close contacts of index cases (ie, individuals who lived in close proximity to index cases, close friends, and partners) who were presumed to be at increased risk of developing symptomatic respiratory tract infection while under observation. We monitored each close contact for 5 days for symptoms and viral shedding and measured transcriptomic responses at each timepoint each day using a blood-based 36-gene RT-PCR assay.

Findings

Between Sept 1, 2009, and April 10, 2015, we enrolled 1465 participants. Of 264 index cases with respiratory tract infection symptoms, 150 (57%) had a viral cause confirmed by RT-PCR. Of their 555 close contacts, 106 (19%) developed symptomatic respiratory tract infection with a proven viral cause during the observation window, of whom 60 (57%) had the same virus as their associated index case. Nine viruses were detected in total. The transcriptomic assay accurately predicted viral infection at the time of maximum symptom severity (mean area under the receiver operating characteristic curve [AUROC] 0·94 [95% CI 0·92–0·96]), as well as at 1 day (0·87 [95% CI 0·84–0·90]), 2 days (0·85 [0·82–0·88]), and 3 days (0·74 [0·71–0·77]) before peak illness, when symptoms were minimal or absent and 22 (62%) of 35 individuals, 25 (69%) of 36 individuals, and 24 (82%) of 29 individuals, respectively, had no detectable viral shedding.

Interpretation

Transcriptional biomarkers accurately predict and diagnose infection across diverse viral causes and stages of disease and thus might prove useful for guiding the administration of early effective therapy, quarantine decisions, and other clinical and public health interventions in the setting of endemic and pandemic infectious diseases.

Funding

US Defense Advanced Research Projects Agency.

ProCommunity: procalcitonin use in real-world US community hospital settings

OBJECTIVE

Procalcitonin (PCT) is a biomarker that may help providers optimize antibiotic (AB) therapy. Numerous clinical trials have demonstrated the utility of PCT-guided decision algorithms in treating lower respiratory tract infections and sepsis, but evidence from real-world studies is limited. This study sought to evaluate the effects of PCT on select clinical outcomes in community hospitals.

METHODS

An observational, retrospective, case-control study was conducted. Hospitals from a large US hospital system were categorized into "treatment" and "control" hospitals. Treatment hospitals were those with in-house PCT testing, a pharmacy team tasked with PCT testing follow-up and results in the patient's electronic medical records alongside a recommendation on AB treatment. Control hospitals either did not have PCT testing available in house or sent out tests to a laboratory or neighboring facility. Patients from treatment hospitals were matched 1:1 to patients from control hospitals based on admission diagnosis code, sex, age and whether an intensive care unit admission was observed. Clinical outcomes included number of days of AB treatment, length of stay, 30 day readmissions, mortality and acute kidney injury. Comparisons were conducted using multivariable regressions accounting for clustering at the hospital level.

RESULTS

Patients from treatment hospitals had significantly shorter hospital stays (-0.68 days, 95% CI: -1.26, -0.09; p = .02). A reduction in days of AB treatment (-1.50 days, 95% CI: -3.27, 0.27; p = .10) was observed, but did not reach statistical significance.

CONCLUSION

These findings suggest that PCT, along with specific treatment recommendations, may lead to shortened hospital stays with no adverse outcome on patient safety.

Diagnostic value of pentraxin 3 in respiratory tract infections: A meta-analysis

BACKGROUND

Pentraxin 3 is an acute inflammatory protein of the long pentraxin subfamily. A meta-analysis was performed to assess diagnostic accuracy of pentraxin 3 for respiratory tract infections.

METHODS

We identify studies examining diagnostic value of pentraxin 3 for respiratory tract infections by searching Pubmed, Web of Knowledge, and Cochrane Library. The sensitivity, specificity, negative likelihood ratio (LR), positive LR, and diagnostic odds ratio were pooled. The area under the summary receiver operator characteristic (SROC) curve and Q point value (Q*) were calculated.

RESULTS

A total of 8 studies with 961 individuals were eligible for this meta-analysis. The pooled sensitivity of pentraxin 3 in diagnosis of respiratory tract infections was 0.78, the pooled specificity was 0.73, the area under the SROC curve was 0.84, and the Q* was 0.77. The area under the SROC curve of serum and bronchoalveolar lavage fluid (BALF) pentraxin 3 was 0.85 and 0.89, respectively. Meta-regression analysis revealed that cutoff value was the source of heterogeneity among the included studies. The Deek funnel plot test suggested no evidence of publication bias. Subgroup analyses showed that the area under the SROC curve of pentraxin 3 in diagnosis of ventilator-associated pneumonia (VAP) was 0.89.

CONCLUSION

Pentraxin 3 has a moderate accuracy for diagnosing respiratory tract infections and VAP. The overall diagnostic value of BALF level of pentraxin 3 is superior to its serum concentration.

Usefulness of infection biomarkers for diagnosing bacteremia in patients with a sepsis code in the emergency department

The objective of this study was to assess the usefulness of the biomarkers lactate, C-reactive protein (CPR) and procalcitonin for the diagnosis of bacteremia in patients with suspected sepsis in the emergency department (ED) and according to the focus of infection. We conducted a retrospective study among patients included in the sepsis code of our ED between November 2013 and December 2017. We analyzed demographic variables, co-morbidity according to the Charlson Index and focus of infection, blood cultures and classification according to Gram staining. We determined the diagnostic performance of the biomarkers quantitatively and calculated the area under the curve (AUC) for global bacteremia and as a function of the focus of infection. We included 653 patients with a median age of 79 years (interquartile range: 66-86), of whom 287 (44.0% were women. The most frequent infectious focus was respiratory (36.1%]. Blood cultures were requested in 87.5% (569 cases). Of the tested samples, 31.3% were positive, of which 63.5% revealed Gram-negative (GN) bacteria. Procalcitonin obtained globally the best AUC 0.70 (95% CI: 0.65-0.75). The values with the best sensitivity and specificity were 2.54 ng/mL for procalcitonin, 4.1 mmol/L for lactate and 156 mg/L for CRP. We found an association between the median procalcitonin value and GN bacteria (6.02; IQR: 1.39-39.40) and Gram-positive bacteria (1.74; IQR: 0.22-15.61). Procalcitonin is the biomarker with the greatest capacity to diagnose bacteremia, particularly in GN infection. Stratification by focus is important since not all biomarkers discriminate in the same way.

Prevalence of respiratory viruses and antiviral MxA responses in children with febrile urinary tract infection

Blood myxovirus resistance protein A (MxA) has broad antiviral activity, and it is a potential biomarker for symptomatic virus infections. Limited data is available of MxA in coinciding viral and bacterial infections. We investigated blood MxA levels in children hospitalized with a febrile urinary tract infection (UTI) with or without simultaneous respiratory virus infection. We conducted a prospective observational study of 43 children hospitalized with febrile UTI. Nasopharyngeal swab samples were collected at admission and tested for 16 respiratory viruses by nucleic acid detection methods. Respiratory symptoms were recorded, and blood MxA levels were determined. The median age of study children was 4 months (interquartile range, 2–14 months). A respiratory virus was detected in 17 (40%) children with febrile UTI. Of the virus-positive children with febrile UTI, 7 (41%) had simultaneous respiratory symptoms. Blood MxA levels were higher in virus-positive children with respiratory symptoms (median, 778 [interquartile range, 535–2538] μg/L) compared to either virus-negative (155 [94–301] μg/L, P < 0.001) or virus-positive (171 [112–331] μg/L, P = 0.006) children without respiratory symptoms at presentation with febrile UTI. MxA differentiated virus-positive children with respiratory symptoms from virus-negative without symptoms by an area under the receiver operating characteristic curve of 0.96. Respiratory viruses were frequently detected in children with febrile UTI. In UTI with simultaneous respiratory symptoms, host antiviral immune response was demonstrated by elevated blood MxA protein levels. MxA protein could be a robust biomarker of symptomatic viral infection in children with febrile UTI.

Glycemic control and FEV1 recovery during pulmonary exacerbations in pediatric cystic fibrosis-related diabetes

RATIONALE

Whether short-term glucose control in cystic fibrosis-related diabetes (CFRD) is associated with FEV₁ recovery during acute pulmonary exacerbations is unclear.

METHODS

Data from all patients with CFRD ages 6-21 years hospitalized in 2010-2016 for pulmonary exacerbations at our CF Center were analyzed, including CFRD status at each encounter, all FEV₁ recorded during each exacerbation, and relevant clinical covariates. Glucose control was analyzed using meter blood glucose area under the curve (AUC) indices. The primary outcome was FEV₁ recovery.

RESULTS

Patients with CFRD who finished IV antibiotics at home were treated for longer than those fully treated in the hospital (22.2 vs. 13.8 days). In those who finished treatment at home, poor inpatient glycemic control was associated with lower lung function improvement: when comparing the 75th to the 25th percentile of each glycemic index (i.e., "poorer" vs. "better" glycemic control), FEV₁ recovery at discharge was 20.1% lower for glucose AUC (95%CI -0.4%, -39.9%); 20.9% lower for 48-h AUC (95%CI -2.7%, -39.1%); and 28.2% lower for AUC/day (95%CI -7.1%, -49.3%). Similar results were found at the end of IV antibiotics and at clinic follow-up. Likewise, patients with poor glycemic control had a lower slope of inpatient FEV₁ recovery. Analysis in patients with normal glucose tolerance was largely non-significant. No associations were found between hemoglobin A1c and FEV₁ recovery.

CONCLUSIONS

In patients with CFRD who complete IV antibiotic treatment at home, poor inpatient glycemic control is associated with worse FEV₁ recovery despite longer duration of treatment.

FebriDx®: A Rapid Diagnostic Test for Differentiating Bacterial and Viral Aetiologies in Acute Respiratory Infections

FebriDx® is a rapid, point-of-care diagnostic test that is designed to aid in the differentiation of bacterial and viral acute respiratory infections (ARIs), thus helping to guide decisions regarding the prescription of antibiotics in the outpatient setting. FebriDx carries a CE mark for use in the EU and is also approved in several other countries, including Canada, Saudi Arabia and Singapore. It is indicated for use in patients > 2 years old with symptoms consistent with a community-acquired ARI. The test involves the use of an immunoassay on a fingerstick blood sample to provide simultaneous, qualitative measurement of elevated levels of C-reactive protein (CRP) and myxovirus resistance protein A (MxA). In two prospective, multicentre studies in patients with acute upper respiratory tract infections, FebriDx was shown to be both sensitive and specific in identifying patients with a clinically significant infection and in differentiating between infections of bacterial and viral aetiology. The test is simple, requires no additional equipment and produces actionable results in ~ 10 min. As was demonstrated in a small, retrospective analysis, FebriDx results can help guide (improve) antibiotic prescribing decisions. Reducing the unnecessary or inappropriate prescription of antibiotics for ARIs of probable viral aetiology is important for antibiotic stewardship and can also reduce the unnecessary exposure of patients to the risk of antibiotic-related adverse events. FebriDx thus represents a useful diagnostic tool in the outpatient setting.

Clinical Progress Note: Procalcitonin in the Management of Pediatric Lower Respiratory Tract Infection

Procalcitonin (PCT) is a biomarker that has shown promise to identify bacterial etiology in acute infections, including bacterial lower respiratory tract infection (LRTI). In 2017, the United States Food and Drug Administration (FDA) approved the use of PCT as a diagnostic aid to guide the decisions around antibiotic therapy in acute LRTI.1 Although most of the data supporting the use of PCT for LRTI stems from adult studies, the high disease burden, predominance of viral etiologies, and frequent diagnostic uncertainty resulting in antibiotic overuse make pediatric LRTI an ideal target for the use of PCT as a diagnostic aid. This review evaluates and summarizes the current evidence regarding the role of PCT in the clinical care of pediatric LRTI, including its use in guiding antibiotic use and prognosticating disease severity.

Metagenomic next-generation sequencing aids the diagnosis of viral infections in febrile returning travellers

OBJECTIVES

Travel-associated infections are challenging to diagnose because of the broad spectrum of potential aetiologies. As a proof-of-principle study, we used MNGS to identify viral pathogens in clinical samples from returning travellers in a single center to explore its suitability as a diagnostic tool.

METHODS

Plasma samples from 40 returning travellers presenting with a fever of ≥38°C were sequenced using MNGS on the Illumina MiSeq platform and compared with standard-of-care diagnostic assays.

RESULTS

In total, 11/40 patients were diagnosed with a viral infection. Standard of care diagnostics revealed 5 viral infections using plasma samples; dengue virus 1 (n = 2), hepatitis E (n = 1), Ebola virus (n = 1) and hepatitis A (n = 1), all of which were detected by MNGS. Three additional patients with Chikungunya virus (n = 2) and mumps virus were diagnosed by MNGS only. Respiratory infections detected by nasal/throat swabs only were not detected by MNGS of plasma. One patient had infection with malaria and mumps virus during the same admission.

CONCLUSIONS

MNGS analysis of plasma samples improves the sensitivity of diagnosis of viral infections and has potential as an all-in-one diagnostic test. It can be used to identify infections that have not been considered by the treating physician, co-infections and new or emerging pathogens.

SUMMARY

Next generation sequencing (NGS) has potential as an all-in-one diagnostic test. In this study we used NGS to diagnose returning travellers with acute febrile illness in the UK, highlighting cases where the diagnosis was missed using standard methods.

Acute Respiratory Tract Infection and 25-Hydroxyvitamin D Concentration: A Systematic Review and Meta-Analysis

Observational studies and randomised controlled studies suggest that vitamin D plays a role in the prevention of acute respiratory tract infection (ARTI); however, findings are inconsistent and the optimal serum 25-hydroxyvitamin D (25(OH)D) concentration remains unclear. To review the link between 25(OH)D concentration and ARTI, we searched PubMed and EMBASE databases to identify observational studies reporting the association between 25(OH)D concentration and risk or severity of ARTI. We used random-effects meta-analysis to pool findings across studies. Twenty-four studies were included in the review, 14 were included in the meta-analysis of ARTI risk and five in the meta-analysis of severity. Serum 25(OH)D concentration was inversely associated with risk and severity of ARTI; pooled odds ratios (95% confidence interval) were 1.83 (1.42-2.37) and 2.46 (1.65-3.66), respectively, comparing the lowest with the highest 25(OH)D category. For each 10 nmol/L decrease in 25(OH)D concentration, the odds of ARTI increased by 1.02 (0.97-1.07). This was a non-linear trend, with the sharpest increase in risk of ARTI occurring at 25(OH)D concentration < 37.5 nmol/L. In conclusion, there is an inverse non-linear association between 25(OH)D concentration and ARTI.

Clinical and Immunological Features of 78 Adult Patients with Primary Selective IgG Subclass Deficiencies

The purpose of this study is to describe both clinical and immunological features in large cohort of adult patients with IgG subclass deficiency, and response to immunoglobulin therapy. This is a retrospective study of data obtained from electronic medical records and paper charts of 78 patients with IgG subclass deficiency seen and followed at our immunology clinics from 2010 to 2016. Both isolated selective IgG subclass deficiency as well as combined (two) subclass deficiencies were observed. IgG3 subclass deficiency, isolated and in combination with other IgG subclass deficiency, is the most frequent of IgG subclass deficiency. A majority of patients presented with upper and lower respiratory tract infections, especially chronic sinusitis. Both allergic and autoimmune manifestations are common; however, there is no subclass preference. The proportions and absolute numbers of CD3⁺ T cells, CD4⁺ T and CD8⁺ T cells, CD19⁺ B cells, and CD3^-CD16⁺CD56⁺ NK cells were normal in the majority of patients in all IgG subclass deficiencies. Total serum IgG levels did not correlate with IgG subclass levels across all IgG subclass deficiencies. Anti-pneumococcal polysaccharide antibody responses were impaired in 56% of patients. IgG3 subclass deficiency is the most common IgG subclass deficiency, and anti-polysaccharide antibody responses are distributed among IgG subclasses with modest preference in IgG2 subclass. The majority of patients treated with immunoglobulin responded by reduction in frequency of infections and requirement of antibiotics.