The Potential Use of Saliva as a Biofluid for Systemic Inflammatory Response Monitoring in Children with Pneumonia

Validation of Serum Calprotectin Relative to Other Biomarkers of Infection in Febrile Infants Presenting to the Emergency Department

Antimicrobial stewardship involves a delicate balance between the risk of undertreating individuals and the potential societal burden of overprescribing antimicrobials. This balance is especially crucial in neonatal care. In this observational study, the usefulness of biomarkers of infectious diseases (calprotectin, procalcitonin (PCT), C-reactive protein (CRP), and white blood cells (WBCs) were evaluated in 141 febrile infants aged 28-90 days presenting to an emergency department. Since our focus was on the usefulness of serum calprotectin, this biomarker was not part of clinical decision-making. A significant difference was observed in the levels of all biomarkers, related to final discharge diagnosis and disposition status. The difference in levels related to antibiotic prescription was significant for all biomarkers but WBCs. The performance of calprotectin in the detection of bacterial infections (AUC (95% CI): 0.804 (0.691, 0.916)) was comparable to the performance of both PCT (0.901 (0.823, 0.980)) and CRP (0.859 (0.764, 0.953)) and superior to the WBC count (0.684 (0.544, 0.823)). Procalcitonin and CRP demonstrated a statistically significantly higher specificity relative to calprotectin. In this cohort, antibiotic use did not always correlate to a definite diagnosis of confirmed bacterial infection. The sample size was limited due to associated challenges with recruiting febrile infants. Hence, there is a need for adequate diagnostic tools to help discriminate between various kinds of infections. This study suggests serum calprotectin, procalcitonin, and CRP may serve as valuable biomarkers to differentiate between types of infection, in addition to clinical input and decision-making.

Saliva Collection Methods Among Children and Adolescents: A Scoping Review

OBJECTIVE

Saliva can be used for screening and diagnostic purposes. Although multiple saliva collection methods are available, their use in children can be limited due to lack of cooperation, developmental stage, and age. The aim of this scoping review was to comprehensively appraise the different methods of saliva collection among both children and adolescents by assessing the available scientific literature.

METHODS

A literature search was performed using the databases PubMed, Embase, and Web of Science. Eligible studies on saliva collection methods among children and adolescents were included for this review.

RESULTS

The literature search identified 249 eligible articles, of which 205 had a cross-sectional study design. Four distinct saliva collection methods have surfaced: the drooling method, the absorption method, the spitting method, and the suction method. Among infants or children under the age of 6 years, the suction and absorption methods were most preferred. The drooling and spitting methods were only applicable among children above the age of 3 years. When children were not willing to cooperate, the absorption method was most feasible. In adolescents and older children, no specific method was found to be preferred over another method.

CONCLUSION

Overall, saliva collection is well tolerated by children and adolescents, with the absorption and suction methods being preferred with young and uncooperative children.

Meta-analysis of serum procalcitonin diagnostic test accuracy for osteomyelitis and septic arthritis in children

The purpose of this study was to evaluate the sensitivity, specificity, and predictive value of serum procalcitonin (PCT) for osteomyelitis and septic arthritis in children. PubMed, EMBase, and Cochrane Library were searched until 10 August 2021, for eligible literature focusing on PCT for the diagnosis of osteomyelitis and septic arthritis. Four articles with six studies were included in the diagnostic meta-analysis, a total of 654 children were examined for bacterial cultures in PCT, osteomyelitis, and septic arthritis. The results of diagnostic meta-analysis showed that the PCT had a sensitivity of 0.72, 95% confidence interval (CI) (0.65-0.79), specificity of 0.90, 95% CI (0.87-0.93), positive likelihood ratio (LR) of 3.87, 95% CI (2.53-5.90), negative LR of 0.39, 95% CI (0.22-0.70), and diagnostic odds ratio was 13.13, 95% CI (6.46-26.66), for the detection of osteomyelitis and septic arthritis using bacterial culture as the gold standard. Based on the summary receiver operating characteristic curve of PCT, it was found that the area under the curve of PCT was 0.88. In the evaluation of publication bias, the result of the regression line test showed that there was not publication bias (bias = 13.72; 95% CI, -1.84 to 29.28; P = 0.07). This study provided systematic review of the published literature on the diagnosis of osteomyelitis and septic arthritis in children using PCT, which may serve as a biomarker for diagnosis of osteomyelitis, but it has no direct evidences to support the diagnosis of septic arthritis. However, the specific optimal cutoff value of PCT and specific population still needed to be verified by large sample studies.

Salivary Biomarkers to Differentiate between Streptococcus pneumoniae and Influenza A Virus-Related Pneumonia in Children

Community-acquired pneumonia (CAP) is common among children and can be fatal in certain conditions. In children, CAP can be caused by viral or bacterial infections. Identification of pathogens can help select appropriate therapeutic strategies. Salivary analysis may be a potential diagnostic tool because it is noninvasive, patient-friendly, and easy to perform in children. A prospective study was conducted in children with pneumonia admitted to a hospital. Salivary samples from patients with definite Streptococcus pneumoniae and influenza A strains were used for gel-free (isobaric tag for relative and absolute quantitation (iTRAQ)) proteomics. No statistically significant difference was detected in salivary CRP levels between Streptococcus pneumoniae and influenza A pneumonia in children. Several potential salivary biomarkers were identified using gel-free iTRAQ proteomics to differentiate pneumonia from Streptococcus pneumoniae or influenza A virus infections in pediatric patients. ELISA validated that Streptococcus pneumoniae group has a higher abundance of salivary alpha 1-antichymotrypsin than those in the influenza A group. Whether these salivary biomarkers can be used to distinguish other bacteria from viral pneumonia requires further verification.

Salivary Diagnostic for Monitoring Strenuous Exercise-A Pilot Study in a Cohort of Male Ultramarathon Runners

Intense physical stress, such as that in ultramarathon running, affects the immune system. For monitoring in sports medicine, non-invasive methods, e.g., salivary analysis, are of interest. This pilot cohort study aimed to assess changes in salivary parameters in response to an ultramarathon. The results were compared to blood parameters. Male, healthy finishers (n = 9, mean age: 48 ± 8.8 years, mean height: 1.8 ± 0.1 m, mean weight: 72.5 ± 7.2 kg, mean BMI: 23.5 ± 1.9 kg/cm²) of a 160 km ultramarathon were included. Saliva and blood samples were collected at three time points: T1 (baseline), T2 (shortly after the ultramarathon) and T3 (after recovery). In saliva, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, albumin, IgA, α-amylase, aMMP-8, and neopterin were assessed via ELISA. In blood, cortisol, testosterone, IL-1β, IL-6, IL-8, IL-10, TNF-α, blood cell counts, procalcitonin, CRP, osmolality, albumin, and α-amylase were analyzed. The statistical evaluation comprised longitudinal testing and cross-sectional testing between saliva and blood using ratios of T2 and T3 to baseline values. Various parameters in saliva and blood changed in response to the ultramarathon. Comparing blood and saliva, the longitudinal changes of testosterone (p = 0.02) and α-amylase (p = 0.03) differed significantly. Despite the limitations of the study, it underlines that saliva is an interesting option for comprehensive monitoring in sports medicine and necessitates further studies.

Self-sampling to identify pathogens and inflammatory markers in patients with acute sore throat: Feasibility study

Introduction

Sore throat is a common reason for overuse of antibiotics. The value of inflammatory or biomarkers in throat swab or saliva samples in predicting benefit from antibiotics is unknown.

Methods

We used the ‘person-based approach’ to develop an online tool to support self-swabbing and recruited adults and children with sore throats through participating general practices and social media. Participants took bacterial and viral swabs and a saliva sponge swab and passive drool sample. Bacterial swabs were cultured for streptococcus (Group A, B, C, F and G). The viral swab and saliva samples were tested using a routine respiratory panel PCR and Covid-19 PCR testing. We used remaining viral swab and saliva sample volume for biomarker analysis using a panel of 13 biomarkers.

Results

We recruited 11 asymptomatic participants and 45 symptomatic participants. From 45 symptomatic participants, bacterial throat swab, viral throat swab, saliva sponge and saliva drool samples were returned by 41/45 (91.1%), 43/45 (95.6%), 43/45 (95.6%) and 43/45 (95.6%) participants respectively. Three saliva sponge and 6 saliva drool samples were of insufficient quantity. Two adult participants had positive bacterial swabs. Six participants had a virus detected from at least one sample (swab or saliva). All of the biomarkers assessed were detectable from all samples where there was sufficient volume for testing. For most biomarkers we found higher concentrations in the saliva samples. Due to low numbers, we were not able to compare biomarker concentrations in those who did and did not have a bacterial pathogen detected. We found no evidence of a difference between biomarker concentrations between the symptomatic and asymptomatic participants but the distributions were wide.

Conclusions

We have demonstrated that it is feasible for patients with sore throat to self-swab and provide saliva samples for pathogen and biomarker analysis. Typical bacterial and viral pathogens were detected but at low prevalence rates. Further work is needed to determine if measuring biomarkers using oropharyngeal samples can help to differentiate between viral and bacterial pathogens in patients classified as medium or high risk using clinical scores, in order to better guide antibiotic prescribing and reduce inappropriate prescriptions.