Plasma fibrinogen level is independent risk factor associated with the incidence of pulmonary infection in patients with spinal cord injury: a retrospective cohort study

BACKGROUND

Patients with spinal cord injury (SCI) are at higher risk of developing pulmonary infection (PI), and plasma fibrinogen level may be an independent risk factor for PI. However, the relationship between fibrinogen level and PI incidence in the SCI population remains unclear. This study aimed to elucidate the association between plasma fibrinogen level and the occurrence of PI among SCI patients.

METHODS

We conducted a retrospective analysis of 576 SCI patients admitted to the Rehabilitation Medicine Department between January 1, 2017, and December 31, 2021. Following exclusions, 491 patients were included in the final analysis, with 139 PI cases identified.

RESULTS

Surgery, level of injury and chest comorbidities were covariates in the relationship between fibrinogen level and PI incidence. Other identified potential risk factors for PI included age, D-dimer level, urinary tract infections (UTI), deep vein thrombosis (DVT), anticoagulant therapy, injury mechanism, and the American Spinal Injury Association Impairment Scale (AIS) grades. After adjusting for these factors, we found that for every 1 g/L increase in fibrinogen level, the risk of developing PI increased by 18% (HR = 1.18, P = 0.011), and indicating a positive linear relationship between fibrinogen level and PI incidence.

CONCLUSION

Plasma fibrinogen was an independent risk factor for PI in patients with SCI, especially for AIS-B and C grades. Proactive management of fibrinogen level after admission to rehabilitation medicine department could be crucial in reducing the incidence of PI in this vulnerable population.

CLINICAL TRIAL NUMBER

Not applicable.

The assessment of pentraxin 3: a diagnostic and prognostic biomarker in lower respiratory tract infections in children

BACKGROUND

Pentraxin 3 (PTX3) is an acute-phase reactant that is elevated in the plasma during inflammatory responses. We aimed to evaluate the utility of PTX3 as a clinical marker in children with lower respiratory tract infections (LRTIs) and the association between PTX3 and LRTIs severity.

METHODS

We included 60 patients admitted to Fayoum University Hospital with LRTIs fulfilling the WHO criteria for diagnosing LRTIs. We collected data on peak temperature, respiratory rate, heart rate, oxygen saturation upon admission, and length of hospital stay. The complete blood count (CBC), C-reactive protein (CRP) level, and PTX3 were measured upon admission.

RESULTS

PTX3 levels were significantly correlated with peak temperature, duration of hospital stay, the Pediatric Respiratory Severity Score (PRESS), total leucocytic count (TLC), CRP, and blood cultures.

CONCLUSION

PTX-3 represented the severity of the disease and predicted the prognosis. Pentraxin levels demonstrate a statistically significant sensitivity of (93.3%) and a specificity of (70%) at the cut-off value (of 8.84) with an area under the curve (90.7%) in the diagnosis of LRTIs.

Routine blood parameters as auxiliary diagnostic tools for Mycoplasma pneumoniae infection in children

Introduction. Recently, the incidence of Mycoplasma pneumoniae (M. pneumoniae) infection in children has been increasing annually. Early differential diagnosis of M. pneumoniae infection can not only avoid the abuse of antibiotics, but also is essential for early treatment and reduction of transmission.Gap statement. The change of routine blood parameters may have important clinical significance for the diagnosis of M. pneumoniae infection, but it has not been reported so far.Aim. This study aims to establish a predictive model for M. pneumoniae infection and explore the changes and clinical value of routine blood parameters in children with M. pneumoniae infection, serving as auxiliary indicators for the diagnosis and differentiation of clinical M. pneumoniae infection.Methodology. A total of 770 paediatric patients with respiratory tract infections were enrolled in this study, including 360 in the M. pneumoniae group, 40 in the SARS-CoV-2 group, 200 in the influenza A virus group, and 170 in the control group. The differences of routine blood parameters among all groups were compared, and risk factors were analysed using multivariate logistics analysis, and the diagnostic efficacy of differential indicators using ROC curves.Results. This study revealed that Mono% (OR: 3.411; 95% CI: 1.638-7.102; P=0.001) was independent risk factor associated with M. pneumoniae infection, and Mono% (AUC=0.786, the optimal cutoff at 7.8%) had a good discriminative ability between patients with M. pneumoniae infection and healthy individuals. Additionally, Mono% (OR: 0.424; 95% CI: 0.231-0.781; P=0.006) and Lymp% (OR: 0.430; 95% CI: 0.246-0.753; P=0.003) were independent risk factors for distinguishing M. pneumoniae infection from influenza A virus infection, and the Lymp% (AUC=0.786, the optimal cutoff at 22.1%) and Net% (AUC=0.761, the optimal cutoff at 65.2%) had good discriminative abilities between M. pneumoniae infection and influenza A infection. Furthermore, platelet distribution width (OR: 0.680; 95% CI: 0.538-0.858; P=0.001) was independent risk factor for distinguishing M. pneumoniae infection from SARS-CoV-2 infection. Meanwhile, the ROC curve demonstrated that PDW (AUC=0.786, the optimal cutoff at 15%) has a good ability to differentiate between M. pneumoniae infection and SARS-CoV-2 infection.Conclusion. This study demonstrates that routine blood parameters can be used as auxiliary diagnostic indicators for M. pneumoniae infection and provide reference for the diagnosis and differentiation of clinical M. pneumoniae infection.

The use of C-reactive protein testing and antibiotic prescribing in Italy: A population-based study in primary care

Testing serum C-reactive protein (CRP) levels can help determine whether there is a need for antibiotics and can limit prescribing of antibiotics for illnesses that are likely viral or non-infectious in origin. Using Health Search, an Italian primary care database, we identified all patients, aged 15 years or older, being registered in the period between 1 January 2000 and 31 December 2019 and newly diagnosed with upper respiratory tract infections (URTIs) or COPD- or asthma-related exacerbations. From the date of these diagnoses, patients were followed up until occurrence of antibiotic prescription (for these indications) up to 31 December 2019. The association between the CRP testing and the outcome was investigated using a nested case-control analysis. In a cohort of 469 684 patients being diagnosed for URTI (83%), COPD- (11%) and asthma (7%)-related exacerbations, 28 688 (6.11%) were prescribed with antibiotics because of the aforementioned indications. Of note, 98% of cases, nominally those prescribed with antibiotics, were not tested with CRP. However, those receiving antibiotics were more likely to have been previously tested for CRP than controls who did not receive antibiotics (833/28 601 [3%] and 4128/277 968 [1.5%]; OR 2.0 [95% CI: 1.8-2.1]). Our findings indicate that most of the antibiotic prescriptions for the investigated conditions were given without any prior CRP testing. A small minority of GPs did properly use CRP to determine whether antibiotics were needed. Further guidance is needed in Italy on the use of CRP in guiding antibiotic prescribing in primary care.

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.

Clinical Profiles, Laboratory Biomarkers, and Mortality in Cancer Patients with Lower Respiratory Tract Infections: A Prospective Cohort Study

Respiratory tract infections (RTIs) pose a substantial health burden worldwide, especially among immunocompromised groups like cancer patients. The aim of this prospective cohort study was to explore lower respiratory tract infections in cancer patients. We followed 107 cases with clinically or radiologically suspected lower respiratory tract infections until discharge or death, comprising 65 males and 42 females across diverse age groups. Clinical evaluations, including patient history, examination, and malignancy diagnosis, were conducted. Nasopharyngeal swabs (NPSs), sputum samples, and blood samples were collected within 24 h of symptom onset. Multiplex Real-Time PCR allowed for the simultaneous detection of viral, bacterial, and fungal infections, while conventional microbiological culture methods were used for bacterial and fungal analysis. SARS-CoV-2 infection was excluded in all of the enrolled patients using real-time RT-PCR. Hematological and biochemical analyses included hemoglobin, lymphocyte, neutrophil, and platelet counts, along with ALT, AST, creatinine, and CRP levels. Significant differences were noted in clinical presentations, management outcomes, and prognostic markers among patients with different hematological malignancies. Distinct clinical profiles were identified for leukemia, lymphoma, and solid tumors, with variations in age distribution and symptom prevalence. ICU admission rates varied significantly, with solid tumor patients exhibiting higher rates. The hematological and biochemical biomarkers differed across malignancies, with notable associations between lymphopenia, thrombocytopenia, and mortality following respiratory episodes. This study highlights the critical role of rapid pathogen detection and infection control measures in safeguarding vulnerable cancer patients from nosocomial transmission.

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.

A Meta-Analysis of Multiple Whole Blood Gene Expression Data Unveils a Diagnostic Host-Response Transcript Signature for Respiratory Syncytial Virus

Respiratory syncytial virus (RSV) is one of the major causes of acute lower respiratory tract infection worldwide. The absence of a commercial vaccine and the limited success of current therapeutic strategies against RSV make further research necessary. We used a multi-cohort analysis approach to investigate host transcriptomic biomarkers and shed further light on the molecular mechanism underlying RSV-host interactions. We meta-analyzed seven transcriptome microarray studies from the public Gene Expression Omnibus (GEO) repository containing a total of 922 samples, including RSV, healthy controls, coronaviruses, enteroviruses, influenzas, rhinoviruses, and coinfections, from both adult and pediatric patients. We identified > 1500 genes differentially expressed when comparing the transcriptomes of RSV-infected patients against healthy controls. Functional enrichment analysis showed several pathways significantly altered, including immunologic response mediated by RSV infection, pattern recognition receptors, cell cycle, and olfactory signaling. In addition, we identified a minimal 17-transcript host signature specific for RSV infection by comparing transcriptomic profiles against other respiratory viruses. These multi-genic signatures might help to investigate future drug targets against RSV infection.

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.