Introduction: Commercially available assays were evaluated in order to determine diagnostic accuracy of Chlamydia trachomatis specific tests for screening. Methods: The study included 225 sexually active men and women, who were tested for genital chlamydial infection in Institute of Public Health Kragujevac. Three screening tests were used: direct immunofluorescence (DIF) and rapid lateral immunochromatographic test (RT) for qualitative detection of chlamydial antigens and immunoenzyme (ELISA) test for detection of serum levels of anti-chlamydial IgA and IgG antibodies. Diagnostic efficiency of these tests were determined in relation to results obtained by RT-PCR method. Results: Statistical significance between the results obtained by RT-PCR as a gold standard and DIF, RT and ELISA were analyzed using chi-square (χ2) test. Statistical analysis showed a significant difference between RT-PCR and analyzed screening tests: DIF (χ2 = 303; p < 0.001), RT (χ2 = 4.19; p = 0.041), serum IgA (χ2 = 4.19; p = 0.041) and serum IgG (χ2 = 67; p < 0.001) which indicates poor agreement between these tests. Large numbers of false positive (FP) and false negative (FN) results were observed for all tested assays. According to Youden’s index, serum IgG and DIF testing demonstrated the most-balanced sensitivity-specificity rate. RT assay exhibits the highest expanded Youden’s index, as well as the best overall diagnostic accuracy. Conclusions: None of evaluated screening tests can be recommended as individual method for the diagnosis of acute infection. We suppose that RT-PCR is unlikely to be a cost-effective screening strategy within the Serbian health system.

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a critical global health threat due to its multidrug resistance, primarily driven by carbapenemase production. Rapid and accurate detection of carbapenemases is essential for effective treatment and infection control. This study evaluates the validity of the NG-Test CARBA 5, a rapid immunochromatographic assay, for detecting five major carbapenemases (KPC, NDM, VIM, IMP, OXA-48-like) in clinical CRKp isolates. Methods: Clinical isolates of CRKp were collected from various clinical specimens at the Military Medical Academy in Belgrade, Serbia, between January 2023 and October 2024. Detection of carbapenemases was performed using NG-Test CARBA 5, while PCR served as the reference method. Diagnostic performance was assessed by calculating sensitivity, specificity, and Cohen’s kappa coefficient. Results: Among 312 isolates, OXA-48-like was the most prevalent carbapenemase. NG-Test CARBA 5 showed high sensitivity (98.7%) and specificity (100%) overall, with excellent agreement for NDM (κ = 0.947), OXA-48-like (κ = 0.957), and KPC (κ = 0.978). However, it failed to detect VIM in five PCR-positive isolates, suggesting potential limitations. Conclusions: NG-Test CARBA 5 is a rapid and reliable tool for detecting major carbapenemases in CRKp, though its performance for VIM detection requires further investigation. This assay has the potential to improve clinical diagnostics and strengthen infection control in settings with high antimicrobial resistance.

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a critical global health threat due to its multidrug resistance, primarily driven by carbapenemase production. Rapid and accurate detection of carbapenemases is essential for effective treatment and infection control. This study evaluates the validity of the NG-Test Carba 5, a rapid immunochromatographic assay, for detecting five major carbapenemases (KPC, NDM, VIM, IMP, OXA-48-like) in clinical CRKp isolates. Methods: Clinical isolates of CRKp were collected from various clinical specimens at the Military Medical Academy in Belgrade, Serbia, between January 2023 and October 2024. Detection of carbapenemases was performed using NG-Test Carba 5, while PCR served as the reference method. Diagnostic performance was assessed by calculating sensitivity, specificity, and Cohen’s kappa coefficient. Results: Among 312 isolates, OXA-48-like was the most prevalent carbapenemase. NG-Test Carba 5 showed high sensitivity (98.7%) and specificity (100%) overall, with excellent agreement for NDM (κ = 0.947), OXA-48-like (κ = 0.957), and KPC (κ = 0.978). However, it failed to detect VIM in five PCR-positive isolates, suggesting potential limitations. Conclusion: NG-Test Carba 5 is a rapid and reliable tool for detecting major carbapenemases in CRKp, though its performance for VIM detection requires further investigation. This assay has the potential to improve clinical diagnostics and strengthen infection control in settings with high antimicrobial resistance.

Respiratory viral infections, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV), represent a common cause of hospitalization among older adults and individuals with comorbidities. This retrospective cohort study, based on prospectively collected surveillance data, aimed to examine the epidemiological and clinical characteristics of hospitalized patients and identify predictors of SARS-CoV-2 and IAV positivity, as well as in-hospital mortality. The study included 832 patients hospitalized at the Military Medical Academy, a tertiary healthcare institution in Belgrade, and tested for respiratory viruses due to symptoms of acute respiratory infection (ARI) between 12 October 2023 and 5 June 2025. Demographic and clinical characteristics, comorbidities, length of hospital stay, and in-hospital outcomes were analyzed using univariable and multivariable logistic regression. SARS-CoV-2 was confirmed in 72 patients (8.7%), whereas IAV was detected in 40 (4.8%). Older age and sore throat were independently associated with SARS-CoV-2 positivity, whereas cough, fatigue, and hypertension were independently associated with IAV positivity. In-hospital mortality was 18.4%. Neither SARS-CoV-2 nor IAV positivity showed a statistically significant association with in-hospital mortality, although the limited numbers of virus-positive patients preclude firm conclusions. Given the overlap in clinical presentation, laboratory testing remains essential for etiological diagnosis, while recognition of these clinical factors may support risk stratification at the time of respiratory virus testing and closer patient monitoring.