Long-term survival of salivary streptococci on dental devices made of ethylene vinyl acetate

Bacterial infection associated with the use of medical or dental devices is a serious concern.Although devices made of ethylene vinyl acetate（EVA） are often used in the oral cavity,there are no established standards for their storage.We investigated bacterial survival on EVA sheets under various storage conditions to establish a standard for hygienic storage of such dental devices.Bacterial counts were evaluated,which showed a significant decrease after washing with sterilized water,mechanical brushing and rinsing,and using Mouthguard Cleaner as compared to untreated samples.In addition,no bacteria were detected on samples stored 2 days or longer in a ventilated environment,whereas they were detected for up to 14 days on samples without any cleaning stored in a closed environment.Bacterial counts for the untreated samples gradually declined,while surviving bacteria on samples treated with sterilized water and mechanical brushing showed a rapid decrease.Additionally,bacterial identification using polymerase chain reaction（PCR） revealed that Streptococcus oralis was dominantly detected on salivary samples after 14 days of storage among both two subjects.For effective hygienic storage of dental devices made of EVA,washing with sterilized water is important to remove absorbed salivary compounds along with storage in a ventilated environment.

Portable Diagnostic Platform for Detection of Microorganisms Coliforms and E.coli

Portable diagnostic devices are a viable and low-cost alternative for the detection of pathogens, since they reduce the time of analysis of results availability. Ease of sample collection and quick diagnosis allow this new input to be applied in the diagnosis of the main contaminating microorganisms present in the water. Laboratory tests evaluated the technical viability of the diagnostic device, using commercial strains which were inoculated and optimized in the devices and their growth compared to the conventional method in Petri dishes. Samples of 100 μL bacterial suspension were tested and compared with the traditional sample inoculation method. The device viability was determined by detecting characteristic bacterial colonies in a specific culture medium through the colorimetric development of the obtained colonies. The feasibility assessments allow us to affirm that the device enables both qualitative and quantitative detection of the target bacteria present in liquid samples, and is promising to be applied to assess the quality of water, food and environmental surfaces.

Assessing decontamination practices at a medical microbiology research laboratory

To our knowledge,this is the first study to conduct an objective assessment of the routine decontamination practices at a medical microbiology research laboratory(MRL)a year after a biosafety training was provided to all laboratory staff.Between March 28th and June 28th,2021,unobtrusive observations were carried out to identify-three high-touch surfaces at the MRL during different working hours.Swabbing was used to evaluate the effectiveness of the disinfectant used in the laboratory.All three high-touch surfaces were sampled before and after decontamination with 200 ppm of 5%sodium hypochlorite(household bleach)to quantify the microbial load and identify the types of organisms residing on the laboratory surfaces.A higher concentration(500 ppm)of 5%sodium hypochlorite was employed after refresher training was provided to housekeeping staff,and resampling of the three surfaces was carried out during a 4-week follow-up period using the same procedure.The three high-touch surfaces identified were the two sides of the workbench(22%–24%)and the front surface of one incubator(14%).Anthracoid bacilli and Staphylococcus aureus were the most commonly found organisms on laboratory surfaces preintervention(100%and 89%,respectively)and post-intervention(56%and 44%,respectively).Other microorganisms detected included Salmonella spp.(27.7%),Proteus spp.(5.6%),Escherichia coli(5.6%),and Klebsiella spp.(33.3%).Employing a higher concentration(500 ppm)of sodium hypochlorite significantly(p<0.000)reduced the total aerobic colony count from an average of 15–250 cfu/cm2 to 10–60 cfu/cm^(2).This study demonstrated suboptimal decontamination practices at the MRL and the need to apply a higher concentration(500 ppm)of sodium hypochlorite to reduce the overall microbial load.It also demonstrated the importance of quantitative assessment to monitor decontamination practices and ensure staff compliance.More studies are needed to identify bacterial communities within the laboratory,which will help provide guidance regarding the types,proper concentrations,and appropriateness of the in-use disinfectants.Furthermore,large-scale studies on the acceptable level of residual contamination following any decontamination process are urgently recommended.