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Objectives: Seroprevalence surveys provide crucial information on cumulative severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure. This Slovenian nationwide population study is the first longitudinal 6-month serosurvey using probability-based samples across all age categories. Methods: Each participant supplied two blood samples: 1316 samples in April 2020 (first round) and 1211 in October/November 2020 (second round). The first-round sera were tested using Euroimmun Anti-SARS-CoV-2 ELISA IgG (ELISA) and, because of uncertain estimates, were retested using Elecsys Anti-SARS-CoV-2 (Elecsys-N) and Elecsys Anti-SARS-CoV-2 S (Elecsys-S). The second-round sera were concomitantly tested using Elecsys-N/Elecsys-S. Results: The populations of both rounds matched the overall population (n = 3000), with minor settlement type and age differences. The first-round seroprevalence corrected for the ELISA manufacturer's specificity was 2.78% (95% highest density interval [HDI] 1.81%–3.80%), corrected using pooled ELISA specificity calculated from published data 0.93% (95% CI 0.00%–2.65%), and based on Elecsys-N/Elecsys-S results 0.87% (95% HDI 0.40%–1.38%). The second-round unadjusted lower limit of seroprevalence on 11 November 2020 was 4.06% (95% HDI 2.97%–5.16%) and on 3 October 2020, unadjusted upper limit was 4.29% (95% HDI 3.18%–5.47%). Conclusions: SARS-CoV-2 seroprevalence in Slovenia increased four-fold from late April to October/ November 2020, mainly due to a devastating second wave. Significant logistic/methodological challenges accompanied both rounds. The main lessons learned were a need for caution when relying on manufacturer-generated assay evaluation data, the importance of multiple manufacturer-independent assay performance assessments, the need for concomitant use of highly-specific serological assays targeting different SARS-CoV-2 proteins in serosurveys conducted in low-prevalence settings or during epidemic exponential growth and the usefulness of a Bayesian approach for overcoming complex methodological challenges.

Urinary tract infections (UTIs) represent a serious global health issue, especially due to emerging multidrug-resistant UTI-causing bacteria. Recently, we showed that the human amniotic membrane (hAM) could be a candidate for treatments and prevention of UPEC and Staphylococcus aureus infections. However, its role against multidrug-resistant bacteria, namely methicillin-resistant S. aureus (MRSA), extended-spectrum beta-lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae, vancomycin-resistant Enterococci (VRE), carbapenem-resistant Acinetobacter baumannii, and Pseudomonas aeruginosa has not yet been thoroughly explored. Here, we demonstrate for the first time that the hAM homogenate had antibacterial activity against 7 out of 11 tested multidrug-resistant strains, the greatest effect was on MRSA. Using novel approaches, its activity against MRSA was further evaluated in a complex microenvironment of normal and cancerous urinary bladder urothelia. Even short-term incubation in hAM homogenate significantly decreased the number of bacteria in MRSA-infected urothelial models, while it did not affect the viability, number, and ultrastructure of urothelial cells. The hAM patches had no antibacterial activity against any of the tested strains, which further exposes the importance of the hAM preparation. Our study substantially contributes to basic knowledge on the antibacterial activity of hAM and reveals its potential to be used as an antibacterial agent against multidrug-resistant bacteria.

Abbott’s Alinity m is a recently launched fully integrated, automated molecular analyzer allowing continuous loading of samples and sample-to-result molecular detection of several microorganisms. Manufacturer-independent clinical evaluation of Alinity m SARS-CoV-2 (Alinity) against cobas 6800 SARS-CoV-2 (cobas) as a standard comparator was performed on 2,157 consecutive nasopharyngeal swabs. Valid initial results of Alinity and cobas were obtained from 2,129/2,157 (98.7%) and 2,157/2,157 (100%) samples, respectively. Overall percent agreement of 98.3% (2,092/2,129; 95%CI:97.6–98.7%), positive percent agreement of 100.0% (961/961; 95%CI:99.6–100.0%), negative percent agreement of 96.8% (1,131/1,168; 95%CI:95.7–97.7%), and a high kappa value of 0.965 (95%CI:0.954–0.976) were observed on 2,129 samples with valid results for both assays. There were 37 discordant results and based on discordant analyses, including previous and/or follow-up PCR results, 22 could be considered Alinity analytically true positive with high probability. Due to the lack of additional information and inability of repeated/further testing, the status of the remaining 15 discordant samples remains unresolved. Comparative real-life throughput of both analyzers assessed while testing 564 samples in parallel across two 8-hour shifts and comparative turnaround time assessment measured while processing in parallel the first 94 routine samples received in the laboratory each working day for 5 consecutive days showed similar real-life performance of both analyzers with certain differences, which has potential importance in some laboratory settings.

Additional file 4 Supplemental Table 4 Proportions of 9 periodontopathogens in positive samples before and 6 months after treatment (Me % [IQR]).

Additional file 3 Supplemental Table 3 Eradication of bacteria present at baseline, 6 months after treatment (n [%]).

Additional file 1 Supplemental Table 1 Proportions (%) of healed sites (HS) at baseline and after 6 months (Me [IQR]).

Additional file 5 Supplemental Table 5 Total counts (CFU/ml) of 9 periodontopathogens in positive samples before and 6 months after treatment (Me counts [IQR]).