Multiplex PCR in Diagnosing Respiratory Tract Infections in Hospitalized Children.

OBJECTIVES: To elaborate the utility of multiplex quantitative polymerase chain reaction (multiplex qPCR) for the accurate diagnosis of severe respiratory tract infections (RTIs) in hospitalized children. METHODS: In two separate periods during 2022, 76 respiratory specimens (combined throat/nasopharyngeal swabs) were submitted for multiplex qPCR regarding 26 respiratory pathogens. The specimens were obtained from children with severe RTIs hospitalized in the Institute for Respiratory Diseases in Children, Skopje. RESULTS: Multiplex qPCR detected at least one respiratory pathogen in all examined specimens (76/76), with 83% (63/76) rate of co-infections. Considering that positive results are only the ones with Ct value below 28, the rates of detected pathogens and co-infections decrease to 75% and 22%, respectively. The most commonly detected pathogens during the spring period were Parainfluenza type 3 (PIV3) followed by Adenovirus (AdV) and Respiratory syncytial virus type B (RSVB) with frequency rate of 23%, 19% and 19%, respectively. During the autumn period, the most common were RSVB and Streptococcus pneumoniae with frequency rate of 31% and 17%, respectively. CONCLUSION: Multiplex qPCR is a powerful tool for diagnosing RTIs. Semi-quantification of the viral load by reporting Ct values added higher level of evidence for accurate diagnosis. Seasonal detection of the examined viruses was notable with higher prevalence of PIV3 in spring and RSVB in autumn period.

Comparison of Oxidative Stress Levels in Healthy Children and Children with Allergic Rhinitis.

Background/aim: Allergic rhinitis (AR) is characterized by chronic inflammation of the nasal mucosa. Under the influence of exogenous factors - allergens, reactive oxygen species (ROS) are released during cellular metabolism. They induce a series of pathological changes in the mucosa. Oxidative stress is а result of an imbalance between the production of ROS and the ability to neutralize them. The aim of this study is to compare the levels of oxidative stress between healthy children and children with allergic rhinitis. Material and methods: A total number of 60 children were included (30 healthy children and 30 children with AR). The oxidative stress index was determined by using the FRAS 5 (Free Radical Analytical System) Bravo system. Demographic characteristics, medical history, children's living conditions and eating habits were obtained from the questionnaire. Anthropometric measurements and the absolute number of eosinophils in the peripheral smear were performed on each child. Results: This study showed high oxidative stress index and a significantly higher value of the absolute number of eosinophils in the peripheral smear in children with AR in comparison to healthy children (p<0.05). The group of children with AR had more atopic characteristics and was more exposed to passive smoking than healthy children. Conclusion: Compared to healthy children, children with AR have a high index of oxidative stress, despite of the very high mean value of the concentration of water-soluble antioxidants in serum (PAT test) in the group of children with AR.

Sputum Quality Assessment Regarding Sputum Culture for Diagnosing Lower Respiratory Tract Infections in Children.

BACKGROUND: The clinical relevance of specimens from the lower airways is often debatable. However, they are most commonly examined for diagnosing lower respiratory tract infections (LRTIs). AIM: This study aimed to determine the diagnostic value of sputum quality assessment about sputum culture for diagnosing LRTIs in children. METHODS: In six months, a total of 1485 sputum samples were quality assessed by using Bartlett's grading system. All samples, regardless of their quality, were cultured, identified, and antimicrobial susceptibility testing was performed by Kirby-Bauer disc-diffusion method. RESULTS: Among the acceptable category, defined by Bartlett's grading system, 132 (63.2%) samples showed culture positivity of which Streptococcus pneumoniae 48 (36.4%) was most commonly isolated, followed by Moraxella catarrhalis 22 (16.7%) and Haemophilus influenza 21 (15.9%). Among the non-acceptable category, 185 (14.5%) samples were culture positive of which most commonly isolated were Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa with 64 (34.6%), 54 (29.2%) and 28 (15.1%), respectively. CONCLUSION: Sputum quality assessment is a useful tool for distinguishing the true respiratory pathogens from possible colonising flora for which antibiotic treatment should not be highly considered.

Comparison of IFN-γ Levels in Children with Tuberculosis Disease (TB) and Latent Tuberculosis Infection (LTBI).

AIM: This study aimed to evaluate the importance of IFN-γ in the diagnosis of pediatric TB and LTBI and to compare the IFN-γ levels. METHODS: We analysed 100 patients examined for possible M. tuberculosis infection or disease at the Institute of Respiratory Diseases in Children, Kozle, Skopje. Patients were divided into 2 groups: TB disease and LTBI. The following parameters were analyzed: demographic characteristics, history of previous exposure to active TB, BCG vaccination and presence of BCG scar, lung X-ray findings, tuberculin skin test by the Monteux method and the value of INF-γ according to the Quantiferon TB gold test, direct samples of acid-alcohol-resistant bacilli of sputum and Löwenstein Jensen cultures. Informed parental consent was obtained for each child included in the study. RESULTS: In the LTBI group 60.9% had a scar from the vaccination while in the TB group 50% had BCG scar. TST induration diameters in children with or without BCG scar were significantly larger in patients with active TB. Children with active TB had significantly higher IFN-γ levels than children with LTBI. The IFN-γ for the cut-off of 0.35 IU/ml, has 64% sensitivity for detection of LTBI, versus 80.6% sensitivity for active disease. Children with close TB contact had significantly higher IFN-γ levels. Correlation between TST induration diameter and IFN-γ levels was stronger in the TB group. CONCLUSION: IFN-γ levels are significantly higher in children with active TB, and children with close contact with TB patient. It has better sensitivity in active TB. Using both tests (IFN-γ and TST) can improve the diagnose of LTBI and TB in countries where vaccination with BCG is widespread.