Procalcitonin Identifies Bacterial Coinfections in Vietnamese Children with Severe Respiratory Syncytial Virus Pneumonia

Performance evaluation of Eu3+-based CRP/SAA and PCT/IL-6 lateral flow immunoassay kits and their diagnostic value in respiratory tract infections

Objectives

Respiratory infections are among the most common infectious diseases, resulting in significant morbidity and mortality. C-reactive protein (CRP), serum amyloid A (SAA), procalcitonin (PCT), and interleukin-6 (IL-6) are advantageous for diagnosing respiratory tract infections. This study assessed the analytical performance and accuracy of new kits for Eu3+-based CRP/SAA and PCT/IL-6 lateral flow immunoassay and its diagnostic value in respiratory tract infections.

Methods

This study evaluated the detection performance of a test kit using guidelines from the Center for Medical Device Evaluation (CMDE) and the Clinical and Laboratory Standards Institute (CLSI). The test results were compared to those of the commercial kits (CRP: Mindray; SAA: Norman; PCT: Shanghai Upper; IL-6: Wantai BioPharm). A total of 156 patients with respiratory tract infections (53 with bacterial infections (Bac group); 50 with viral infections (Vir group); and 53 with co-infections (Bac + Vir group)) were enrolled, along with 50 healthy controls (HC group). Venous blood samples were collected to measure levels of SAA, PCT, CRP, and IL-6 using both the test and commercial kits. The diagnostic value of these biomarkers was assessed using receiver operating characteristic (ROC) curves.

Results

Correlation analysis demonstrated a strong concordance between the test kits and commercial kits (CRP: r = 0.9396, P < 0.0001; SAA: r = 0.8986, P < 0.0001; PCT: r = 0.9594, P < 0.0001; IL-6: r = 0.9009, P < 0.0001). The diagnostic performance of the test kits in identifying bacterial, viral, and co-infections was highly consistent with that of the commercial kit.

Conclusions

The Eu3+-based CRP/SAA and PCT/IL-6 lateral flow immunoassay test kits demonstrated high levels of consistency with commercial kits in terms of quantitative outcomes and diagnostic performance for respiratory tract infections.

Clinical characteristics and prognosis of paediatric respiratory syncytial virus-related encephalopathy

BACKGROUND

To understand the clinical characteristics and prognosis of respiratory syncytial virus (RSV)-related encephalopathy in children.

METHODS

A retrospective analysis of the data of children who were diagnosed with RSV-related encephalopathy and admitted to the paediatric intensive care unit (PICU) of Beijing Children's Hospital between November 2016 and November 2023 was performed.

RESULTS

Four hundred and sixty-four children with RSV infection were treated in the PICU, and eight of these patients (1.7%) were diagnosed with RSV-related encephalopathy. The mean age of the patients was 24.89 (5.92 ∼ 36.86) months. Two patients had underlying diseases. The time from the onset of illness to impaired consciousness was 3 (1.88-3.75) days. Five patients had convulsions, and three patients had an epileptic status. The serum procalcitonin (PCT) level was 1.63 (0.24, 39.85) ng/ml for the eight patients, and the cerebrospinal fluid (CSF) protein level was 232 (163 ∼ 848) g/L. Among the 8 patients, four patients underwent electroencephalogram (EEG) monitoring or examination. One patient showed continuous low-voltage, nonresponsive activity, and another patient displayed persistent slow waves, the remaining two patients had negative results. One patient had a combination of acute necrotizing encephalopathy (ANE) and acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Additionally, one patient had ANE, and another had acute brain swelling (ABS). One patient died in the hospital, and the other seven patients were discharged with improvement. Routine follow-up was conducted for 4.58(0.5 ∼ 6.50) years, and all patients fully recovered.

CONCLUSIONS

RSV-related encephalopathy could have varying clinical manifestations, and some types, such as ANE and ABS, are dangerous and can lead to death.

C-Reactive Protein Levels in Children with Acute Bronchiolitis

Background and Objectives. Acute bronchiolitis is a common respiratory disease in children. C-reactive protein (CRP) is an indicator of bacterial coinfection. This study is aimed at assessing the frequency of elevated CRP in children with acute bronchiolitis and at comparing the clinical characteristics, laboratory and radiological findings, antibiotics use, and outcome according to CRP levels. Material and Methods. We retrospectively reviewed medical records of children with acute bronchiolitis admitted to Pediatric Department, Salmaniya Medical Complex, Bahrain, in 2019-2020. Demographic, clinical, laboratory and radiological data, and outcomes were collected. Patients with high CRP were compared with those with normal levels. Results. Of 287 patients, 229 (79.2%) were included. 132 (57.6%) were males. Median presentation age was 3.7 (interquartile range (IQR), 1.27-12.33) months. Median CRP level was 10.4 (IQR, 2.8-35.1) mg/L. CRP was high in 167 (72.9%) patients. 17.6% (33/187 patients) had confirmed bacterial coinfection. Respiratory syncytial virus (RSV) was detected in 84 (36.7%) patients. Mean CRP level was higher in RSV-negative compared to RSV-positive patients, $31.3\pm 44.3$ versus $21.5\pm 27.7\text{mg}/\text{L}$ , respectively ( $P=0.042$ ). Respiratory viral serology profile was positive in 34.7% (17/49 patients). 66.9% (107/160 patients) had positive chest X-ray. Antibiotics were used in 78.1% (179/227 patients). Thirteen (5.7%) patients required intensive care, five (2.2%) had surgical intervention, four (1.8%) required endotracheal intubation, and four (1.8%) died. Patients with high CRP were older at presentation ( $P<0.0001$ ) and had more fever ( $P<0.0001$ ) and cough ( $P=0.002$ ), but lower hemoglobin level ( $P<0.0001$ ) compared to those with normal CRP. Fever ( $P=0.016$ ) and hemoglobin level ( $P=0.002$ ) were independent factors. Conclusion. Most children with acute bronchiolitis had high rate of elevated CRP values that did not correlate with the rate of bacterial coinfection. High CRP levels were found in older children, those presented with more fever and cough, and had a lower hemoglobin level despite that those factors were previously reported to be associated with disease severity and bacterial coinfection. This study also showed a high overall rate of antibiotic prescriptions in mostly viral disease.

The Clinical Diagnostic Values of SAA, PCT, CRP, and IL-6 in Children with Bacterial, Viral, or Co-Infections

Background

Bacterial, viral, and bacterial and viral co-infections generally lead to inflammatory-related diseases. The aim of this study is to assess the clinical diagnostic values of serum amyloid A (SAA), procalcitonin (PCT), C-reactive protein (CRP), and interleukin (IL)-6 in children with bacterial, viral, or co-infections.

Methods

A total of 181 children with infection symptoms (bacterial infection (Bac group), n = 46; viral infection (Vir group), n = 7; co-infections (Bac + Vir group), n = 128) were enrolled in our hospital from December 2019 to April 2020. Meanwhile, 42 healthy children without any infections were used as the controls. Venous blood samples were collected and the levels of serum SAA, PCT, CRP, and IL-6 were determined by immunoluminometric assay under an IMMAGE^® analyzer. The diagnostic values of these biomarkers were assessed using the receiver operating characteristic (ROC) curves.

Results

The results indicated that IL-6 level was increased in three infection groups compared to the controls. Both SAA and CRP were significantly elevated in Vir and Bac + Vir groups. High level of PCT was observed in Bac and Bac + Vir goups. In addition, PCT (0.9281, 95% CI = 0.8645-0.9916) alone is an effective method for identifying bacterial infections. SAA in combination with CRP may distinguish co-infection from bacterial infection. Simultaneous positive of SAA, PCT, IL-6, and CRP can discriminate co-infection from the healthy controls.

Conclusion

In a word, the levels of serum SAA, PCT, CRP, and IL-6 are increased to varying degrees in different infection situations. Our findings may provide early diagnosis for patients with different infections.

Clinical utility of procalcitonin and its association with pathogenic microorganisms

In this review, we summarize the relationship of PCT with pathogens, evaluate the clinical utility of PCT in the diagnosis of clinical diseases, condition monitoring and evaluation, and guiding medical decision-making, and explore current knowledge on the mechanisms by which pathogens cause changes in PCT levels. The lipopolysaccharides of the microorganisms stimulate cytokine production in host cells, which in turn stimulates production of serum PCT. Pathogens have different virulence mechanisms that lead to variable host inflammatory responses, and differences in the specific signal transduction pathways result in variable serum PCT concentrations. The mechanisms of signal transduction have not been fully elucidated. Further studies are necessary to ascertain the PCT fluctuation range of each pathogen. PCT levels are helpful in distinguishing between certain pathogens, in deciding if antibiotics are indicated, and in monitoring response to antibiotics.