Secondary attack rate of COVID-19 in shared households in Slovakia.

OBJECTIVE: The objective of this study was to estimate the secondary attack rate in unvaccinated members of households of two regions in the Slovak Republic for the period November 2020 ‒ April 2021. INTRODUCTION: SARS-CoV-2 infection poses a high risk of transmission in close-contact indoor settings, such as households. The household transmissibility of SARS-CoV-2 varies widely across countries. METHODS: We included 278 households for SARS-CoV-2 transmission analysis. We calculated the secondary attack rate (SAR). We assessed sex, level of disease severity and means of isolation during infection of index cases as determinants of disease transmissibilityRESULTS: The secondary attack rate in 278 households was estimated at 63.7% (95%CI: 58.2‒66.7%). The SARs were different by sex (60.2% in females, 67.5% in males). The highest SAR was observed in the households of asymptomatic cases (77.8%), followed by moderate severity (66.5%), hospital admissions (63.2%) and mild disease (58.2%). CONCLUSION: We found a high household secondary attack rate in two regions of Slovakia in the period when Alpha variant (B.1.1.7) of SARS-CoV-2 was dominant in the country. The results highlight the importance of monitoring transmission dynamics (Tab. 1, Fig. 1, Ref. 12). Text in PDF www.elis.sk Keywords: COVID-19, secondary attack rate, Slovak Republic, households.

MALDI-TOF MS analysis as a useful tool for an identification of Legionella pneumophila, a facultatively pathogenic bacterium interacting with free-living amoebae: A case study from water supply system of hospitals in Bratislava (Slovakia).

Legionellae, i.e. Legionella pneumophila, are human bacterial hydrophilic facultative pathogens causing pneumonia (Legionnaires' disease). Free-living amoebae (FLA) can serve as natural hosts and thus as reservoirs of many amoebae-resistant bacteria. An encysted amoeba can contribute to the resistance of intracellular L. pneumophila to various chemical and physical treatments. Humans can be infected by droplets containing bacteria from an environmental source or human-made devices such as shower heads, bathtubs, air-conditioning units or whirlpools. In this study, we were investigating the presence of FLA and L. pneumophila in plumbing systems of healthcare facilities in Bratislava (Slovakia) by standard diagnostic methods, while the presence of L. pneumophila was verified also by MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) analysis. The results showed the occurrence of L. pneumophila and FLA in 62.26% and 66.4% of samples taken from four paediatric clinics, respectively. Both standard methods and MALDI-TOF MS showed comparable results and they can be successfully applied for the identification of L. pneumophila strains in environmental samples. Our approach could be useful for further monitoring, prevention and decreasing risk of Legionella infection also in other hospitals.

Legionnaires' Disease in Pediatric Patients, Control Measures and 5-Year Follow-up.

BACKGROUND: Legionnaires' disease (LD) occurs predominantly in adults and elderly people. Its incidence in Europe has been increasing in recent years. It is rare in younger age groups and prone to be reported as healthcare-associated infection with a higher risk of fatal outcome. Hospital-acquired LD is mostly associated with a colonized hospital water system. We describe 5 LD cases in a children's hospital in Slovakia, subsequent environmental investigation, control measures, and 5-year monitoring of Legionella colonization in hospital's water system. METHODS: In 2014-2019, we tested clinical specimens from 75 hospitalized patients. Respiratory samples were cultured for Legionella, patient's urine was tested for Legionella urinary antigens, and the microagglutination test was used for serologic testing. Samples of water were collected in 2015-2019 and processed according ISO11731. RESULTS: We identified 5 Legionella infections in 2014-2015. Median age of patients was 15 years. All were high-risk patients hospitalized for their underlying diseases. All patients required admission to intensive care unit, and artificial ventilation due to general deterioration and respiratory failure. Legionella pneumophila was isolated from 72% of water samples. Chlorine dioxide dosing into water system above 0.3 ppm caused significant decrease of Legionella concentration in water samples. Samples taken from outlets with antimicrobial filter installed were legionellae-negative. CONCLUSIONS: Control measures led to decreased risk of infection, but not to eradication of Legionellae. It is necessary to extend the diagnostics for Legionella infection in hospitalized children with pneumonia, especially in hospitals with colonized water system.