assessing natural mineral water microbiology quality in the absence of cultivable pathogen bacteria

Abstract Italian Directives recommend the good quality of natural mineral waters but literature data assert a potential risk from microorganisms colonizing wellsprings and mineral water bottling plants. We evaluated the presence of microorganisms in spring waters (SW) and bottled mineral waters (BMW) samples. Routine microbiological indicators, additional microorganisms like Legionella spp., Nontuberculous mycobacteria (NTM) and amoebae (FLA) were assessed in 24 SW and 10 BMW samples performing cultural and molecular methods. In 33 out of 34 samples, no cultivable bacteria ≥10 CFU/L was found. Cultivable FLA were detected in 50% of water samples. qPCR showed the presence of Legionella qPCR units in 24% of samples (from 1.1 × 102 to 5.8 × 102 qPCR units/L) and NTM qPCR units in 18% of samples (from 1 × 102 to 1 × 105 qPCR units/L). Vermamoeba vermiformis and Acanthamoeba polyphaga were recovered respectively in 70% of BMW samples (counts from 1.3 × 103 to 1.2 × 105 qPCR units/L) and 42% of SW samples (from 1.1 × 103 to 1.3 × 104 qPCR units/L). Vahlkampfia spp. was detected in 42% of SW and 70% of BMW samples (from 1.2 × 103 to 1.2 × 105 qPCR units/L). Considering the presence of FLA, we underline the importance of a wider microbiological risk assessment in natural mineral waters despite the absence of cultivable bacteria

Biofilm growth on orthopedic implantable materials: static or dynamic condition what is the most appropriate methodological tools to study device-related infections?

Aim Study of biofilm growth under static and dynamic conditions to evaluate the most suitable orthopedic materials on the prevention of device-related infections. Method Biofilms of Staphylococcus epidermidis (ATCC 35984) icaA and icaD genes positive and Pseudomonas aeruginosa (DSM 939) were generated under static and dynamic conditions, adding the bacterial inocula on titanium, carbon, polycarbonate and carbon-peek coupons housed in flat bottom test tubes or in the CDC Biofilm Reactor (CBR) system respectively. Biofilm growth was evaluated by MTT assay after 48 hours. Results Results of dynamic model showed a better capacity of S.epidermidis to grow with a rotation between 120-60 rpm on each tested materials (Mann-Whitney test, p-value < 0,05) than P.aeruginosa. Titanium was thematerial on which the bacterial strains adhered less, whereas carbon and polycarbonate allowed greatest adherence of P.aeruginosa (Mann-Whitney test, p-value < 0,05). Results of static model showed that both species grew on each materials without distinction (Kruskal-Wallis test, p-value 0,95). S.epidermidis growth was better also under static condition. Conclusions the static model was not able to evaluate the different adhesion capacity of the strains to the materials, confirming the dynamic model is the most suitable tool for the study of orthopedic materials on the prevention of device-related infections. This research was funded by the University of Pisa, PRA 2017_18 Projec

Presence of Legionella spp. in Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

Although the European reports highlight an increase in community-acquired Legionnaires' disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or on the first floor and on the last floor, while the potable water quality was analysed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remote tap. Legionella pneumophila sg1, Legionella pneumophila sg2-16, and non-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease and/or the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 °C and 37 °C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control

Evaluation of Legionella pneumophila Decrease in Hot Water Network of Four Hospital Buildings after Installation of Electron Time Flow Taps

Legionella spp. control is a critical issue in hospital with old water networks. Chemical disinfection methods are applied as a control measure over prolonged time periods, but Legionella may be resistant to chemical agents in pipeworks with low flow and frequent water stagnation. We evaluated Legionella spp. colonization in the hot water network of Italian hospitals after the installation of time flow taps (TFTs). In the period between 2017 and 2019, TFTs were installed in four hospital water networks. They were programmed in order to obtain a hot water flow of 192 L/day from each TFTs. A continuous chlorination system (chlorine dioxide) and a cold water pre-filtration device were applied in all the buildings. Before and after TFT installation, Legionella spp. was investigated at scheduled times. Before TFT installation, Legionella pneumophila was detected in all the hospitals with counts ranging from 2 × 102 to 1.4 × 105 CFU/L. After TFT installation, a loss in Legionella pneumophila culturability was always achieved in the period between 24 h and 15 days. Total chlorine concentration (Cl2) was detected in the range between 0.23 and 0.36 mg/L while temperature values were from 44.8 to 53.2 °C. TFTs together with chemical disinfection represent a method which improve water quality and disinfectant efficacy, reducing Legionella colonization in dead-end sections

Colonization by Legionella spp. of water networks in residential buildings of the Province of Pisa, Italy

Despite the increase of community acquired cases of legionellosis in Italy over the last years, the Italian guidelines do not give indications for prevention and control of Legionella in the hot water networks (or centralized conditioning systems) of residential buildings. We performed a survey on eight medium sized apartment buildings in the Pisa district to assess the prevalence of Legionella spp. in the water network and the respondance to drinking water requisites at the point of use, according to the Italian norms

Evaluation of a modified cleaning procedure in the prevention of carbapenem-resistant Acinetobacter baumannii clonal spread in a burn intensive care unit using a high-sensitivity luminometer

Background: Enhanced environmental cleaning practices are among the most accepted measures for controlling the spread of carbapenem-resistant . Acinetobacter baumannii (CR-Ab). Aim: To evaluate the impact of heightened cleaning on an ongoing CR-Ab outbreak in a burn intensive care unit (BICU) of an Italian teaching hospital, where chlorhexidine-60% isopropyl alcohol was applied as a complementary disinfectant on high-touch surfaces. Methods: Compliance with the microbial limit proposed for the BICU by AFNOR-NF-S90-351 (20 colony-forming units/100cm2) was assessed by plate count, and compared with the results obtained with intracellular adenosine triphosphate (ATP) detection. Genotyping was performed using pulsed-field gel electrophoresis. Findings: During the standard cleaning regimen, three out of 23 samples (13%) gave results over the AFNOR limit and five (21.7%) showed unacceptable ATP levels with 100 relative light units/100cm2 as the benchmark limit (sensibility 86.4%, specificity 92.2%). Following improvement of the cleaning procedure, only two samples out of 50 (4%) did not satisfy the microbiological criteria and seven (14%) exceeded the ATP limit. In a successive phase, eight of 30 samples collected showed unacceptable results (27%). Conclusions: Adding chlorhexidine-60% isopropyl alcohol as complementary disinfectant proved to be effective for reducing environmental microbial contamination, ATP levels and CR-Ab infection/colonization in patients admitted to the BICU. Real-time monitoring by ATP assay was useful for managing the cleaning schedule and reducing hospital infections, although the calculated values must be interpreted as cleanliness indicators rather than risk indicators

Asbestos in drinking water and hazards to human health: a narrative synthesis

The term asbestos refers to six unique fibrous minerals mostly used in the production of asbestos cement sheets and pipes. According to the World Health Organization and the International Agency for Research on Cancer (IARC), there exists at least "sufficient evidence" that all types of asbestos may cause cancer in humans (mesothelioma, lung cancer, laryngeal tumor and ovarian cancer). The only asbestos limit in drinking water is 7 million fiber/liter. This study is a narrative synthesis about the possible hazards to human health related to the presence of asbestos in drinking water. The various scientific studies and epidemiological reports examined highlight that there is an ongoing debate on the possible carcinogenic risk associated with asbestos exposure through ingestion. Nevertheless, considering the latency with which diseases caused by asbestos may emerge, control measures should be adopted

Application of hydrogen peroxide as an innovative method of treatment for Legionella control in a hospitalwater network

Objectives: To evaluate the effectiveness of hydrogen peroxide (HP) use as a disinfectant in the hospital water network for the control of Legionella spp. colonization. Methods: Following the detection of high levels of Legionella contamination in a 136-bed general hospital water network, an HP treatment of the hot water supply (25 mg/L) was adopted. During a period of 34 months, the effectiveness of HP on Legionella colonization was assessed. Legionella was isolated in accordance with ISO-11731 and identification was carried out by sequencing of the mip gene. Results: Before HP treatment, L. pneumophila sg 2-15 was isolated in all sites with a mean count of 9950±8279 cfu/L. After one-month of HP treatment, we observed the disappearance of L. pneumophila 2-15, however other Legionella species previously not seen were found; Legionella pneumophila 1 was isolated in one out of four sampling sites (2000 cfu/L) and other non-pneumophila species were present in all sites (mean load 3000±2887 cfu/L). Starting from September 2013, HP treatment was modified by adding food-grade polyphosphates, and in the following months, we observed a progressive reduction of the mean load of all species (p < 0.05), resulting in substantial disappearance of Legionella colonization. Conclusion: Hydrogen peroxide demonstrated good efficacy in controlling Legionella. Although in the initial phases of treatment it appeared unable to eliminate all Legionella species, by maintaining HP levels at 25 mg/L and adding food-grade polyphosphates, a progressive and complete control of colonization was obtained

Time related variations in stem cell harvesting of umbilical cord blood

Umbilical cord blood (UCB) contains hematopoietic stem cells and multipotent mesenchymal cells useful for treatment in malignant/nonmalignant hematologic-immunologic diseases and regenerative medicine. Transplantation outcome is correlated with cord blood volume (CBV), number of total nucleated cells (TNC), CD34+ progenitor cells and colony forming units in UCB donations. Several studies have addressed the role of maternal/neonatal factors associated with the hematopoietic reconstruction potential of UCB, including: gestational age, maternal parity, newborn sex and birth weight, placental weight, labor duration and mode of delivery. Few data exist regarding as to how time influences UCB collection and banking patterns. We retrospectively analyzed 17.936 cord blood donations collected from 1999 to 2011 from Tuscany and Apulia Cord Blood Banks. Results from generalized multivariable linear mixed models showed that CBV, TNC and CD34+ cell were associated with known obstetric and neonatal parameters and showed rhythmic patterns in different time domains and frequency ranges. The present findings confirm that volume, total nucleated cells and stem cells of the UCB donations are hallmarked by rhythmic patterns in different time domains and frequency ranges and suggest that temporal rhythms in addition to known obstetric and neonatal parameters influence CBV, TNC and CD34+ cell content in UBC units

Reprogramming normal cells into tumour precursors requires ECM stiffness and oncogene-mediated changes of cell mechanical properties

Defining the interplay between the genetic events and microenvironmental contexts necessary to initiate tumorigenesis in normal cells is a central endeavour in cancer biology. We found that receptor tyrosine kinase (RTK)–Ras oncogenes reprogram normal, freshly explanted primary mouse and human cells into tumour precursors, in a process requiring increased force transmission between oncogene-expressing cells and their surrounding extracellular matrix. Microenvironments approximating the normal softness of healthy tissues, or blunting cellular mechanotransduction, prevent oncogene-mediated cell reprogramming and tumour emergence. However, RTK–Ras oncogenes empower a disproportional cellular response to the mechanical properties of the cell’s environment, such that when cells experience even subtle supra-physiological extracellular-matrix rigidity they are converted into tumour-initiating cells. These regulations rely on YAP/TAZ mechanotransduction, and YAP/TAZ target genes account for a large fraction of the transcriptional responses downstream of oncogenic signalling. This work lays the groundwork for exploiting oncogenic mechanosignalling as a vulnerability at the onset of tumorigenesis, including tumour prevention strategies