Worker safety and glutaraldehyde in the gastrointestinal lab environment

Disinfection of otorhinolaryngological endoscopes with electrolyzed acid water: A cross-sectional and multicenter study

Glutaraldehyde, a germicide for reprocessing endoscopes that is important for hygiene in the clinic, might be hazardous to humans. Electrolyzed acid water (EAW) has a broad anti-microbial spectrum and safety profile and might be a glutaraldehyde alternative. We sought to assess EAW disinfection of flexible endoscopes in clinical otorhinolaryngological settings and its in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and bacteria commonly isolated in otorhinolaryngology. Ninety endoscopes were tested for bacterial contamination before and after endoscope disinfection with EAW. The species and strains of bacteria were studied. The in vitro inactivation of bacteria and SARS-CoV-2 by EAW was investigated to determine the efficacy of endoscope disinfection. More than 20 colony-forming units of bacteria at one or more sampling sites were detected in 75/90 microbiological cultures of samples from clinically used endoscopes (83.3%). The most common genus detected was Staphylococcus followed by Cutibacterium and Corynebacterium at all sites including the ears, noses, and throats. In the in vitro study, more than 107 CFU/mL of all bacterial species examined were reduced to below the detection limit (<10 CFU/mL) within 30 s after contact with EAW. When SARS-CoV-2 was treated with a 99-fold volume of EAW, the initial viral titer (> 105 PFU) was decreased to less than 5 PFU. Effective inactivation of SARS-CoV-2 was also observed with a 19:1 ratio of EAW to the virus. EAW effectively reprocessed flexible endoscopes contributing to infection control in medical institutions in the era of the coronavirus disease 2019 pandemic.

Thresholds in chemical respiratory sensitisation

There is a continuing interest in determining whether it is possible to identify thresholds for chemical allergy. Here allergic sensitisation of the respiratory tract by chemicals is considered in this context. This is an important occupational health problem, being associated with rhinitis and asthma, and in addition provides toxicologists and risk assessors with a number of challenges. In common with all forms of allergic disease chemical respiratory allergy develops in two phases. In the first (induction) phase exposure to a chemical allergen (by an appropriate route of exposure) causes immunological priming and sensitisation of the respiratory tract. The second (elicitation) phase is triggered if a sensitised subject is exposed subsequently to the same chemical allergen via inhalation. A secondary immune response will be provoked in the respiratory tract resulting in inflammation and the signs and symptoms of a respiratory hypersensitivity reaction. In this article attention has focused on the identification of threshold values during the acquisition of sensitisation. Current mechanistic understanding of allergy is such that it can be assumed that the development of sensitisation (and also the elicitation of an allergic reaction) is a threshold phenomenon; there will be levels of exposure below which sensitisation will not be acquired. That is, all immune responses, including allergic sensitisation, have threshold requirement for the availability of antigen/allergen, below which a response will fail to develop. The issue addressed here is whether there are methods available or clinical/epidemiological data that permit the identification of such thresholds. This document reviews briefly relevant human studies of occupational asthma, and experimental models that have been developed (or are being developed) for the identification and characterisation of chemical respiratory allergens. The main conclusion drawn is that although there is evidence that the acquisition of sensitisation to chemical respiratory allergens is a dose-related phenomenon, and that thresholds exist, it is frequently difficult to define accurate numerical values for threshold exposure levels. Nevertheless, based on occupational exposure data it may sometimes be possible to derive levels of exposure in the workplace, which are safe. An additional observation is the lack currently of suitable experimental methods for both routine hazard characterisation and the measurement of thresholds, and that such methods are still some way off. Given the current trajectory of toxicology, and the move towards the use of non-animal in vitro and/or in silico) methods, there is a need to consider the development of alternative approaches for the identification and characterisation of respiratory sensitisation hazards, and for risk assessment.

Adverse staff health outcomes associated with endoscope reprocessing

There are occupational challenges associated with cleaning, disinfecting, storing, and transporting flexible endoscopes. Although the Occupational Safety and Health Administration (OSHA) has set standards to protect the safety of health workers in the United States, the standards are not specific to endoscope reprocessing, and the general standards that are in place are not fully implemented. Furthermore, adverse staff outcomes may not be fully preventable. To assess the evidence for adverse outcomes in staff associated with endoscope reprocessing, a literature review was performed in the PubMed database for articles on this topic published between Jan. 1, 2007 and March 7, 2012. Eight studies were identified, mainly European, which reported numerous adverse outcomes to healthcare personnel associated with endoscope reprocessing including respiratory ailments and physical discomfort. More scientifically rigorous studies are required to comprehensively describe adverse health outcomes in personnel engaged in reprocessing, particularly in the United States, and examine whether increased automation of the reprocessing process leads to decreased adverse health outcomes for staff.

The effect of work practices on personal exposure to glutaraldehyde among health care workers

Glutaraldehyde is a potential sensitizer and has been implicated in the literature as a cause of respiratory irritation and asthma among health care workers. In order to evaluate the effect of work practices and general ventilation system on employees' peak exposure to glutaraldehyde, 42 breathing zone personal air samples were taken in five hospitals. In addition, work practices were observed and recorded during the course of sampling and were classified into three categories. Presence of local or general ventilation system, air change per hour, and quantity of glutaraldehyde used were also recorded. Geometric mean concentration of all samples was 0.025 ppm (GSD=3.05). Statistical analysis indicated that work practice was the most important factor affecting the level of exposure to glutaraldehyde. In locations where "poor" or "unsafe" work practices were employed, the geometric mean concentrations were much higher (GM=0.05, GSD=2.11 and GM 0.08, GSD=1.52, respectively). The result has indicated higher prevalence of headache and itchy eyes among employees who worked where unsafe work practices were observed. Employing proper work practices can significantly reduce exposure to glutaraldehyde among health care workers. It has been recently proposed that the current occupational exposure limit of 0.2 ppm shall be reduced to either 0.1 or 0.05 ppm in the province of Québec (Canada). In this case, it is likely that concentration levels higher than these levels be experienced in some workplaces. Therefore, it is imperative that employers initiate necessary corrective action immediately.