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Background: In response to the COVID-19 health emergency, mass media widely spread guidelines to stop the virus transmission, leading to an excessive and unaware use of detergents and disinfectants. In Italy and in other countries this tendency caused a significant increase of exposures to these products in 2020. Evaluating data collected by the Italian Pavia Poison Centre (PPC), this study intends to examine the relationship between the COVID-19 lockdown and the variations of exposures to specific product categories possibly associated to the containment measures implemented. Simultaneously, this work shows the effectiveness of the European Product Categorisation System (EuPCS) in surveillance activities of dangerous chemicals., Methods: Exposure cases managed by the PPC during March-May 2020 (lockdown) and during the same months of 2017-2018-2019 were compared. Differences in categorical variables were tested with the Chi-square test. The level of significance was set at Alpha = .05. The study included all EuPCS groups but specifically focused on cleaners, detergents, biocides and cosmetics., Results: During the lockdown, calls from private citizens showed a highly significant increase (+ 11.5%, p < .001) and occupational exposures decreased (- 11.7%, p = .011). Among Cleaners, exposures to Bleaches slightly increased while Drain cleaning products went through a significant reduction (- 13.9%, p = .035). A highly significant increase of exposures to Disinfectants was observed (+ 7.7%, p = .007), particularly to those for surfaces (+ 6.8%, p = .039). Regarding Cosmetics, both handwashing soaps and gel products significantly increased (respectively: + 25.0, p = .016 and + 9.7%, p = .028). Among children 1-5 years, the statistical significance is reached with exposures to Dishwashing detergents (+ 13.1%, p = .032), handwashing soaps (+ 28.6%, p = .014) and handwashing gel products (+ 16.8%, p = .010). Contrarily, Liquid Laundry Detergent Capsules decreased in a highly significant manner (- 25%; p = .001). The general severity of exposures showed a highly significant decrease (Moderate: - 10.1%, p = .0002)., Conclusions: This study investigated the relationship between the COVID-19 lockdown and the variations of exposures to some product categories related to the containment measures. The results obtained support any action to be taken by Competent Authorities to implement measures for a safer use of cleaners/disinfectants. This paper shows the benefit in applying the EuPCS to categorize products according to their intended use, though an extension of this system to products not covered by CLP Regulation may be a further advantage., (© 2022. The Author(s).)

Background: The enoyl-acyl carrier protein (ACP) reductase enzyme (FabI) is the target for a series of antimicrobial agents including novel compounds in clinical trial and the biocide triclosan. Mutations in fabI and heterodiploidy for fabI have been shown to confer resistance in S. aureus strains in a previous study. Here we further determined the fabI upstream sequence of a selection of these strains and the gene expression levels in strains with promoter region mutations., Results: Mutations in the fabI promoter were found in 18% of triclosan resistant clinical isolates, regardless the previously identified molecular mechanism conferring resistance. Although not significant, a higher rate of promoter mutations were found in strains without previously described mechanisms of resistance. Some of the mutations identified in the clinical isolates were also detected in a series of laboratory mutants. Microarray analysis of selected laboratory mutants with fabI promoter region mutations, grown in the absence of triclosan, revealed increased fabI expression in three out of four tested strains. In two of these strains, only few genes other than fabI were upregulated. Consistently with these data, whole genome sequencing of in vitro selected mutants identified only few mutations except the upstream and coding regions of fabI, with the promoter mutation as the most probable cause of fabI overexpression. Importantly the gene expression profiling of clinical isolates containing similar mutations in the fabI promoter also showed, when compared to unrelated non-mutated isolates, a significant up-regulation of fabI., Conclusions: In conclusion, we have demonstrated the presence of C34T, T109G, and A101C mutations in the fabI promoter region of strains with fabI up-regulation, both in clinical isolates and/or laboratory mutants. These data provide further observations linking mutations upstream fabI with up-regulated expression of the fabI gene.

Background: Biofilm formation in E. faecalis is presumed to play an important role in a number of enterococcal infections. We have previously identified a genetic locus provisionally named bop that is involved in maltose metabolism and biofilm formation. A transposon insertion into the second gene of the locus (bopB) resulted in loss of biofilm formation, while the non-polar deletion of this gene, together with parts of the flanking genes (bopA and bopC) resulted in increased biofilm formation. A polar effect of the transposon insertion on a transcriptional regulator (bopD) was responsible for the reduced biofilm formation of the transposon mutant., Results: The amount of biofilm formed is related to the presence of maltose or glucose in the growth medium. While the wild-type strain was able to produce biofilm in medium containing either glucose or maltose, two mutants of this locus showed opposite effects. When grown in medium containing 1% glucose, the transposon mutant showed reduced biofilm formation (9%), while the deletion mutant produced more biofilm (110%) than the wild-type. When grown in medium containing 1% maltose, the transposon mutant was able to produce more biofilm than the wild-type strain (111%), while the deletion mutant did not produce biofilm (4%). Biofilm formation was not affected by the presence of several other sugar sources. In a gastrointestinal colonization model, the biofilm-negative mutant was delayed in colonization of the mouse intestinal tract., Conclusion: The biofilm-positive phenotype of the wild-type strain seems to be associated with colonization of enterococci in the gut and the presence of oligosaccharides in food may influence biofilm formation and therefore colonization of enterococci in the gastrointestinal system.