Effectiveness Of Decontamination Procedures Research Articles

Surface Contamination of Reusable Respirators and Face Shields During Care of Critically Ill COVID-19 Patients.

With the emergence of SARS-CoV-2, healthcare workers (HCW) have relied on reusable personal protective equipment (PPE), including respirators and face shields (FSs). The effectiveness of decontamination procedures outside experimental settings is unclear. We examined the prevalence of surface contamination on reusable PPE used by HCWs at a hospital incorporating daily centralized decontamination and post-use wiping by sampling for common pathogens. Samples were collected from HCWs' CleanSpace Halo respirator face masks (FMs) and FSs at the start of shift, immediately after use, and after cleaning with disinfecting wipes. Samples were analyzed for pathogens using the Applied Biosystems™ TaqPath™ COVID-19 Combo Kit and ThermoFisher TaqMan Array Card. Patient charts were reviewed for clinical correlation. Of the 89 samples, 51 from FMs and 38 from FSs, none tested positive for SARS-CoV-2, despite 58 being obtained from PPE used in the care of patients with COVID-19, many with recent aerosol-generating procedures. Four samples tested positive (4.5%) for Staphylococcus aureus, two each from FMs and FSs. FMs that tested positive were not worn concurrently with FSs that tested positive. The FM and FS samples testing positive were worn in the care of patients without diagnosed S. aureus infection. No FMs tested positive following wipe-based disinfection, but both positive FS samples were found after disinfection wiping. Contamination of reusable PPE appears uncommon, especially with SARS-CoV-2, when regular decontamination programs are in place. The rare presence of S. aureus highlights the importance of doffing procedures and hand hygiene by HCW to prevent surface contamination.

A systematic investigation of forensic hair decontamination procedures and their limitations.

The effectiveness of decontamination procedures used for the removal of external drug contamination in forensic hair analysis is an ongoing debate. This investigation evaluated wash methods complying with Society of Hair Testing (SoHT) guidelines and their capacity to remove cocaine (COC) and methamphetamine (MA) from artificially contaminated hair. The most effective decontamination method was determined using a systematic approach, involving (1) an initial washing solvent screen, (2) optimization of wash duration, (3) comparison of sequential wash methods, and (4) reanalysis of clinical hair samples. For analysis, hair was subjected to micro-pulverized methanolic extraction prior to quantitation by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Methanol (MeOH) and 0.1M phosphate buffer (pH6) were the most effective organic and aqueous solvents, respectively, removing 28%-38% of COC and 16%-31% of MA. Wash durations longer than 30-60minutes did not remove additional amounts, and a more efficient sequential wash method was subsequently developed. Despite this, the interpretation of reportable results relative to the SoHT cut-off levels was unchanged for most clinical hair samples reanalyzed after washing by agitation for 30minutes with MeOH. These findings highlight the inability of decontamination solvents to completely remove external COC and MA contamination from hair, including wash methods adhering to SoHT guidelines.

The effect of decontamination procedures on elastic polymeric materials used in dental mouthguards fabrication

Mouthguards are commonly used in the prevention of head and mouth injuries in many sport disciplines. Elastic polymeric materials used in their fabrication absorb the energy of impact. However, decontamination procedures may cause damage to their surface causing deterioration of their properties and favouring pathogen colonization. The aim of the study was to determine the impact of different cleaning methods on mouthguard materials, surface quality. The material for the research consisted of 81 samples made from polymeric materials used for custom mouthguard fabrication - Impak, Corflex Orthodontic and Erkoflex. Samples were viewed under a scanning electron microscope after exposure to different cleaning methods. Statistical analysis of tested decontamination procedures and disinfecting agents showed statistically important ( p < 0.05) results for the presence of small and big separated pieces, grooves and holes. Out of all the cases the lowest indicator for occurrence was in the disinfecting spray - Aftermat. Considering the importance of the surface material of the mouthguard, disinfection should be the method of choice for maintaining its hygiene. Impak material samples, cleaned with the Aftermat spray, showed the lowest range of damage.

The effectiveness of decontamination procedures used in forensic hair analysis

Hair is a mainstream specimen used in forensic toxicology to determine drug use and exposure. However, the interpretation of an analytical hair result can be complicated by the presence of external drug contamination. Decontamination procedures are included in hair analysis methods to remove external contamination, but the capacity of these washes to completely remove contamination for all drugs is controversial. It is evident that there is no consensus on the most effective decontamination procedure, nor can decontamination procedures consistently remove external drug contamination to less than reportable cut-offs for all analytes. ∆9-tetrahydrocannabinol deposited from cannabis smoke is mostly removed by organic solvents, whereas ionizable drugs are more effectively removed by an aqueous wash. Organizations such as the Society of Hair Testing recommend a hair decontamination procedure should include both an organic and aqueous washing step, which is in accordance with the reviewed literature. Studies involving a systematic evaluation of various solvents have shown that the most effective organic solvent was methanol and the most effective aqueous solvent contained sodium dodecyl sulfate detergent. If future systematic studies can demonstrate similar findings, a consensus on the most effective decontamination procedure for forensic hair analysis may be established.

Contamination of firefighter personal protective equipment and skin and the effectiveness of decontamination procedures

ABSTRACTFirefighters' skin may be exposed to chemicals via permeation/penetration of combustion byproducts through or around personal protective equipment (PPE) or from the cross-transfer of contaminants on PPE to the skin. Additionally, volatile contaminants can evaporate from PPE following a response and be inhaled by firefighters. Using polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) as respective markers for non-volatile and volatile substances, we investigated the contamination of firefighters' turnout gear and skin following controlled residential fire responses. Participants were grouped into three crews of twelve firefighters. Each crew was deployed to a fire scenario (one per day, four total) and then paired up to complete six fireground job assignments. Wipe sampling of the exterior of the turnout gear was conducted pre- and post-fire. Wipe samples were also collected from a subset of the gear after field decontamination. VOCs off-gassing from gear were also measured pre-fire, post-fire, and post-decon. Wipe sampling of the firefighters' hands and neck was conducted pre- and post-fire. Additional wipes were collected after cleaning neck skin. PAH levels on turnout gear increased after each response and were greatest for gear worn by firefighters assigned to fire attack and to search and rescue activities. Field decontamination using dish soap, water, and scrubbing was able to reduce PAH contamination on turnout jackets by a median of 85%. Off-gassing VOC levels increased post-fire and then decreased 17–36 min later regardless of whether field decontamination was performed. Median post-fire PAH levels on the neck were near or below the limit of detection (< 24 micrograms per square meter [µg/m2]) for all positions. For firefighters assigned to attack, search, and outside ventilation, the 75th percentile values on the neck were 152, 71.7, and 39.3 µg/m2, respectively. Firefighters assigned to attack and search had higher post-fire median hand contamination (135 and 226 µg/m2, respectively) than other positions (< 10.5 µg/m2). Cleansing wipes were able to reduce PAH contamination on neck skin by a median of 54%.

The effect of decontamination procedures on the pharmacodynamics of venlafaxine in overdose.

To investigate the relationship between decontamination procedures and seizure events caused by venlafaxine overdose and to estimate the time at which 90% of patients would have had their first seizure in the presence and absence of decontamination. Data were collected from 319 patients who took an overdose of venlafaxine on 436 occasions. Seizures occurred on 24 of 436 occasions (5%). Patients received one of single dose activated charcoal (SDAC), whole bowel irrigation (WBI), a combination of either (SDAC/WBI) or no decontamination. Logistic regression and time to event analysis were used to investigate the influence of dose and decontamination on the probability of seizures and time to 90% (t(90) ) of seizure, respectively. A linear logistic regression model described the data. Simulation from the model showed that the probability of seizure was 0.05 (0.03-0.08), 0.19 (0.09-0.35) and 0.75 (0.30-0.96) at 1000, 5000 and 10 000 mg, respectively (median and 95% credible interval). At the mean dose of 2100 mg the odds ratios (OR) in the presence of SDAC, WBI and SDAC/WBI were 0.48 (0.25-0.89), 0.71 (0.35-1.22) and 0.25 (0.08-0.62), respectively. A modified Gompertz model described the time to seizure events. Simulations from the Gompertz model showed that the t(90) values for first seizure was 26 h and was not affected by dose or decontamination procedure. SDAC/WBI provided greater benefits than the sum of the independent effects of SDAC and WBI. Patients should be observed for at least 24 h for seizures based on the dose and risk of seizure occurring.

The Effect of Decontamination Procedures on the Pharmacokinetics of Venlafaxine in Overdose

The aim of this work was to investigate the pharmacokinetics (PK) of venlafaxine in overdose and the effects of single-dose activated charcoal (SDAC) and whole-bowel irrigation (WBI), alone or in combination, as methods of decontamination. The data included 339 concentration-time points from 76 venlafaxine overdose events (median dose 2,625 (150-13,500 mg)); 69 were slow-release doses. SDAC, WBI, a combination of both, or no decontamination were administered to patients as decided by the treating clinician. The data were modeled using WinBUGS (Windows Bayesian Inference Using Gibbs Sampling). A one-compartment model with first-order input and elimination provided an adequate description of the data. SDAC increased clearance (CL) of venlafaxine by 35%, and SDAC and WBI combined reduced the fraction absorbed by 29%. However, the latter produced a greater reduction in maximum plasma concentration (C(max)) for a similar drop in area under the plasma concentration-time curve (AUC). Both SDAC alone, and a combination of SDAC and WBI, decreased the AUC after venlafaxine overdose, but the combination may be more beneficial because it reduces peak concentrations to a greater extent.

Effect of decontamination procedures on recovery of Nocardia spp.

Exposure to 0.5% N-acetyl-L-cysteine (NAC), 2% NaOH-NAC, or benzalkonium chloride in trisodium phosphate (Zephiran-TSP) was toxic for Nocardia isolates. The number of viable Nocardia cells in a standardized suspension was reduced by 10(2) to 10(6) after a 30-min exposure to 2% NaOH-NAC and by 10(4) or more after a 30-min treatment with Zephiran-TSP.