Prevention of legionellosis remains a critical issue in healthcare settings where monochloramine (MC) disinfection was recently introduced as an alternative to chlorine dioxide in controlling ...Legionella spp. contamination of the hospital water network. Continuous treatments with low MC doses in some instances have induced a viable but non-culturable state (VBNC) of Legionella spp.
To investigate the occurrence of such dormant cells during a long period of continuous MC treatment.
Between November 2010 and April 2015, 162 water and biofilm samples were collected and Legionella spp. isolated in accordance with standard procedures. In sampling sites where MC was <1.5mg/L, VBNC cells were investigated by ethidium monoazide bromide (EMA)–real-time polymerase chain reaction (qPCR) and ‘resuscitation’ test into Acanthamoeba polyphaga CCAP 1501/18. According to the Health Protection Agency protocol, free-living protozoa were researched in 60 five-litre water samples.
In all, 136 out of 156 (87.2%) of the samples taken from sites previously positive for L. pneumophila ST269 were negative by culture, but only 47 (34.5%) negative by qPCR. Although no positive results were obtained by EMA-qPCR, four out of 22 samples associated with MC concentration of 1.3 ± 0.5mg/L showed VBNC legionella resuscitation. The presence of the amoeba A. polyphaga in the hospital water network was demonstrated.
Our study is the first report evidencing the emergence of VNBC legionella during a long period of continuous MC treatment of a hospital water network, highlighting the importance of keeping an appropriate and uninterrupted MC dosage to ensure the control of legionella colonization in hospital water supplies.
We identified a discrete number of microRNAs differentially expressed in benign or malignant mesothelial tissues. We focused on mir-145 whose levels were significantly downregulated in malignant ...mesothelial tissues and malignant pleural mesothelioma (MPM) cell lines as compared to benign tissues (pleura, peritoneum or cysts). We show that promoter hyper-methylation caused very low levels in MPM cell lines and specimens. Treatment of MPM cell lines with mir-145 agonists negatively modulated some protumorigenic properties of MPM cells, such as clonogenicity, cell migration and resistance to pemetrexed treatment. The main effector mechanism of the clonogenic death induced by mir-145 was that of accelerated senescence. We found that mir-145 targeted OCT4 via specific binding to its 3'-UTR. Increased intracellular levels of mir-145 decreased the levels of OCT4 and its target gene ZEB1, thereby counteracting the increase of OCT4 induced by pemetrexed treatment which is known to favor the development of chemoresistant cells. In line with this, reintroduction of OCT4 into mimic-145 treated cells counteracted the effects on clonogenicity and replicative senescence. This further supports the relevance of the mir-145-OCT4 interaction for the survival of MPM cells. The potential use of mir-145 expression levels to classify benign vs malignant mesothelial tissues and the differences between pemetrexed-induced senescence and that induced by the re-expression of mir-145 are discussed.
In hospital water systems legionellae may be resistant to disinfectants in pipework, which is a problem particularly in areas where there is low flow or stagnation of water. We evaluated legionella ...colonization of a water network of an Italian hospital after time flow taps (TFTs) installation in proximity to dead legs. The water volume flushed was 64 L/day from May 2016, and 192 L/day from December 2016. Before TFTs installation, Legionella pneumophila sg2-14 was detected in all points (4 × 104 ± 3.1 × 104 cfu/L). All sites remained positive (2.9 × 104 ± 1.9 × 104 cfu/L) through November 2016. From December 2016 legionella persisted in one point only (2 × 102 to 6.8 × 103 cfu/L). TFTs with chemical disinfection may reduce legionella colonization associated with dead legs.
Microbiological surveillance of endoscopes is a safety measure for verifying the quality of reprocessing procedures and identifying contaminated devices, but duodenoscope-related outbreaks are still ...reported.
To assess the effectiveness of duodenoscope reprocessing procedures in Italy.
Between December 2019 and April 2020, data obtained from microbiological surveillance post-reprocessing in 15 Italian endoscopy units were collected. Sampling was carried out after reprocessing or during storage in a cabinet. In keeping with international guidelines and the Italian position paper, the micro-organisms were classified as high-concern organisms (HCOs) and low-concern organisms (LCOs).
In total, 144 samples were collected from 51 duodenoscopes. Of these, 36.81% were contaminated: 22.92% were contaminated with HCOs and 13.89% were contaminated with LCOs 2.08% with an LCO load of 11–100 colony-forming units (CFU)/device and 0.69% with an LCO load of >100 CFU/device. The contamination rate was 27.5% in samples collected after reprocessing, 40% in samples collected during storage in a cabinet that was compliant with EN 16442:2015 (C-I), and 100% in samples collected during storage in a cabinet that was not compliant with EN 16442:2015 (NC-I). The respective HCO rates were 15.00%, 27.27% and 66.67%. Correlation between LCO contamination and storage time was demonstrated (Spearman's rho=0.3701; P=0.0026). The Olympus duodenoscope TJFQ180V demonstrated the lowest rate of contamination (29.82%), although the contamination rate was 100% for duodenoscopes stored in an NC-I cabinet.
Microbiological surveillance, along with strict adherence to reprocessing protocols, may help to detect endoscope contamination at an early stage, and reduce the risk of duodenoscope-associated infections.
Summary Background Patients receiving haemodialysis are exposed to a large volume of dialysis fluid. The Italian Society of Nephrology (ISN) published guidelines and microbial quality standards on ...dialysis water (DW) and solutions to ensure patient safety. Aim : Aim of the study was to identify microbial and chemical hazards and to evaluate disinfection treatments quality in DW plants. Methods: In the years 2015 and 2016 water networks and DW plants (closed loop and online monitors) of nine dialysis wards of Italian hospitals, hosting 162 dialysis beds overall, were sampled on a monthly basis to determine the parameters provided by ISN guidelines. Chlorinated drinking water was desalinated by reverse osmosis and distributed to the closed loop which feeds all online monitors. Disinfection with peracetic acid was performed in all DW plants on a monthly basis. Findings: During the entire study period of 24 months 7 out of 9 DW plants (78%) recorded negative results for all investigated parameters. A closed loop contamination of Burkholderia cepacia was detected in a DW plant from January 2015 to March 2015. Pseudomonas aeruginosa was isolated from March 2016 to May 2016 in the closed loop of another DW plant. These microbial contaminations were eradicated by shock disinfection with sodium hypochlorite and peracetic acid, followed by water flushing. Conclusion: Our results highlight the importance of chemical and physical methods of DW disinfection. The maintenance of control measures in water plants hosted in dialysis wards ensures a microbial risk reduction for all dialysis patients.
Summary The presence of pathogenic viruses in healthcare settings represents a serious risk for both staff and patients. Direct viral detection in the environment poses significant technical problems ...and the indirect indicators currently in use suffer from serious limitations. The aim of this study was to monitor surfaces and air in hospital settings to reveal the presence of hepatitis C virus, human adenovirus, norovirus, human rotavirus and torque teno virus by nucleic acid assays, in parallel with measurements of total bacterial count and haemoglobin presence. In total, 114 surface and 62 air samples were collected. Bacterial contamination was very low (<1 cfu/cm2 ) on surfaces, whereas the ‘medium’ detected value in air was 282 cfu/m3 . Overall, 19 (16.7%) surface samples tested positive for viral nucleic acids: one for norovirus, one for human adenovirus and 17 (14.9%) for torque teno virus (TTV). Only this latter virus was directly detected in 10 air samples (16.1%). Haemoglobin was found on two surfaces. No relationship was found between viral, biochemical or bacterial indicators. The data obtained confirm the difficulty of assessing viral contamination using bacterial indicators. The frequent detection of TTV suggests its possible use as an indicator for general viral contamination of the environment.
Summary Background Waterborne pathogens such as Pseudomonas spp. and Legionella spp. may persist in hospital water networks despite chemical disinfection. Point-of-use filtration represents a ...physical control measure that can be applied in high-risk areas to contain the exposure to such pathogens. New technologies have enabled an extension of filters’ lifetimes and have made available faucet hollow-fibre filters for water ultrafiltration. Aim The aim of this study was the comparison of point-of-use filters applied to cold water within their period of validity. Methods Faucet hollow-fibre filters (filter “A”), shower hollow-fibre filters (filter “B”) and faucet membrane filters (filter “C”) were contaminated in two different sets of tests with standard bacterial strains ( Pseudomonas aeruginosa DSM 939 and Brevundimonas diminuta ATCC 19146) and installed at points-of-use. Every day, from each faucet, 100 L of water were flushed. Before and after flushing, 250 ml of water was collected and analyzed for microbiology. Findings Results showed a high capacity of microbial retention from filter “C”; filter “B” released only low Brevundimonas counts; filter “A” showed a poor retention of both microorganisms. Conclusion Hollow-fibre filters did not show a good microorganism retention. All point-of-use filters require an appropriate maintenance of structural parameters to ensure their efficiency.
Enhanced environmental cleaning practices are among the most accepted measures for controlling the spread of carbapenem-resistant Acinetobacter baumannii (CR-Ab).
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.
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.
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%).
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.
PDF
