Publications by authors named "Giuseppina Frezza"

5 Publications

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virucidal efficacy of a dry steam disinfection system against Human Coronavirus, Human Influenza Virus, and Echovirus.

J Occup Environ Hyg 2021 Oct 20:1-6. Epub 2021 Oct 20.

Department of Surgery Medicine Dentistry and Morphological Sciences with an Interest in Transplant Oncology, University of Modena and Reggio Emilia, Modena, Italy.

This study was aimed to assess the efficacy of dry steam in inactivating Human Coronavirus OC43 (HCoV-OC43) as surrogate of SARS-CoV-2, Human Influenza Virus A/H1N1/WSN/33 and Echovirus 7 on stainless steel, polypropylene, and cotton. The virus models were chosen on the basis of their transmission route and environmental resistance. Tests were carried out under a laminar flow cabinet, where two panels of each material were contaminated with a viral suspension. The inocula were left to dry and then the virus on untreated panel (control) was collected by swabbing in order to determine the initial titer. The other panel was treated using a professional vacuum cleaner equipped with a dry steam generator. Dry steam is generated in a boiler where tap water is heated up to 155 °C at 5.5 bar pressure and then during the passage along the flexible hose the temperature decreases to a value between 100 °C and 110 °C at the output. The dry steam was applied for four sec with a window wiper on metal and plastic panels or a brush covered by a microfiber cap on cotton, simulating the steam application during routine cleaning. After the treatment, infectious virus possibly remained on the surface was collected following the same swabbing procedure applied for controls. HCoV-OC43 and Echovirus 7 were titrated by end-point method on HCT-8 line cells and Vero cells, respectively, while Human Influenza Virus was quantified by plaque reduction assay on MDCK cells. Dry steam resulted effective against the three viruses on all tested materials, achieving a mean Log reduction factor ≥4 in viral titer of treated samples compared with controls according to UNI EN 14476:2019. Thus, dry steam may be proposed as an ease to use, effective, fast, and nontoxic alternative to chemicals for surface disinfection without damaging materials. Therefore, this device could be employed not only in healthcare facilities but also in occupational, domestic, and community settings, with advantages for environment and human health.
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http://dx.doi.org/10.1080/15459624.2021.1989442DOI Listing
October 2021

Safety and Effectiveness of Monochloramine Treatment for Disinfecting Hospital Water Networks.

Int J Environ Res Public Health 2020 08 22;17(17). Epub 2020 Aug 22.

Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy.

The formation of potentially carcinogenic N-nitrosamines, associated with monochloramine, requires further research due to the growing interest in using this biocide for the secondary disinfection of water in public and private buildings. The aim of our study was to evaluate the possible formation of N-nitrosamines and other toxic disinfection by-products (DBPs) in hospital hot water networks treated with monochloramine. The effectiveness of this biocide in controlling spp. contamination was also verified. For this purpose, four different monochloramine-treated networks, in terms of the duration of treatment and method of biocide injection, were investigated. Untreated hot water, municipal cold water and, limited to N-nitrosamines analysis, hot water treated with chlorine dioxide were analyzed for comparison. spp. contamination was successfully controlled without any formation of N-nitrosamines. No nitrification or formation of the regulated DBPs, such as chlorites and trihalomethanes, occurred in monochloramine-treated water networks. However, a stable formulation of hypochlorite, its frequent replacement with a fresh product, and the routine monitoring of free ammonia are recommended to ensure a proper disinfection. Our study confirms that monochloramine may be proposed as an effective and safe strategy for the continuous disinfection of building plumbing systems, preventing vulnerable individuals from being exposed to legionellae and dangerous DBPs.
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http://dx.doi.org/10.3390/ijerph17176116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7503937PMC
August 2020

Characterisation of Microbial Community Associated with Different Disinfection Treatments in Hospital hot Water Networks.

Int J Environ Res Public Health 2020 03 24;17(6). Epub 2020 Mar 24.

Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy.

Many disinfection treatments can be adopted for controlling opportunistic pathogens in hospital water networks in order to reduce infection risk for immunocompromised patients. Each method has limits and strengths and it could determine modifications on bacterial community. The aim of our investigation was to study under real-life conditions the microbial community associated with different chemical (monochloramine, hydrogen peroxide, chlorine dioxide) and non-chemical (hyperthermia) treatments, continuously applied since many years in four hot water networks of the same hospital. Municipal cold water, untreated secondary, and treated hot water were analysed for microbiome characterization by 16S amplicon sequencing. Cold waters had a common microbial profile at genera level. The hot water bacterial profiles differed according to treatment. Our results confirm the effectiveness of disinfection strategies in our hospital for controlling potential pathogens such as , as the investigated genera containing opportunistic pathogens were absent or had relative abundances ≤1%, except for non-tuberculous mycobacteria, , and . Monitoring the microbial complexity of healthcare water networks through 16S amplicon sequencing is an innovative and effective approach useful for Public Health purpose in order to verify possible modifications of microbiota associated with disinfection treatments.
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http://dx.doi.org/10.3390/ijerph17062158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143765PMC
March 2020

The relevance of molecular genotyping to allocate cases in a suspected outbreak of Legionella pneumonia in patients with prolonged immunosuppressive therapy.

Int J Infect Dis 2020 Feb 7;91:174-176. Epub 2019 Nov 7.

Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Modena, Italy.

Three cases of pneumonia caused by Legionella pneumophila serogroup 1 (Lp1) in immunosuppressed patients with repeated hospitalization were suspected as a healthcare-associated cluster. The environmental investigation did not reveal the presence of legionellae in the hospital patient rooms. Water samples collected from the homes of two patients were also negative for Legionella spp. In the absence of environmental strains potentially involved in the infections, we proceeded to genotype environmental Lp1 strains isolated in the hospital during routine water sampling during the decade 2009-2019 and recovered after long-term storage at -20°C. These 'historical' strains exhibited a high grade of similarity and stability over time, regardless of the disinfection systems. The different molecular profiles shown among the clinical and environmental strains excluded a nosocomial outbreak. The study suggests that the application of molecular typing may be a useful tool to discriminate hospital vs community-acquired cases, mostly for severely immunosuppressed patients in whom the symptomatology could be insidious and the incubation period could be prolonged. Moreover, the genotyping allowed us to exclude any link between the cases.
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http://dx.doi.org/10.1016/j.ijid.2019.11.002DOI Listing
February 2020

Control of Legionella contamination in a hospital water distribution system by monochloramine.

Am J Infect Control 2012 Apr 8;40(3):279-81. Epub 2011 Jul 8.

Department of Public Health Sciences, University of Modena and Reggio Emilia, Italy.

Background: We report the results of 1-year application of monochloramine to control Legionella pneumophila contamination in a hospital hot water distribution system.

Methods: In the main building of the hospital, a device continuously distributing monochloramine was installed. Legionella pneumophila and Pseudomonas spp contamination was followed in comparison with 2 other water networks in the same building using chlorine dioxide.

Results: Monochloramine significantly reduced the number of contaminated sites compared with baseline (from 97.0% to 13.3%, respectively), chlorine dioxide device I (from 100% to 56.7%, respectively), and device II (from 100% to 60.8%, respectively). No positive sample exceeded 10(4) colony-forming units/L versus 59.4% at baseline.

Conclusion: Monochloramine could represent a good alternative to chlorine dioxide in controlling legionellae contamination in public and private buildings.
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http://dx.doi.org/10.1016/j.ajic.2011.03.008DOI Listing
April 2012
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