Publications by authors named "Gerald McDonnell"

The identification of worst-case device (or device set) features has been a well-established validation approach in many areas (e.g., terminal sterilization) for determining process effectiveness and requirements, including for reusable medical devices.

View Article and Find Full Text PDF

Endotoxins are high-molecular-weight complexes that contain lipopolysaccharide, protein, and phospholipid originating from the outer membrane of gram-negative bacteria. As gram-negative bacteria are naturally present in a variety of sources, endotoxins are commonly identified as contaminants in manufacturing environments. In industrial applications, endotoxin often is considered difficult to inactivate and to have a strong affinity with surfaces resulting from its hydrophobic chemical structure.

View Article and Find Full Text PDF

Radiation methods are widely used for disinfection and sterilization applications. Microorganisms demonstrate known, variable tolerance levels to inactivation with lower doses of ionizing and non-ionizing radiation based on multiple mechanisms of resistance in their structures and nucleic acid repair mechanisms. The radiation dose required to ensure microbial inactivation during sterilization is typically based on the understanding and routine monitoring of the natural population and resistance of microorganisms on products exposed to radiation sterilization processes.

View Article and Find Full Text PDF

Introduction: Although the US Government considers threats of misinformation, disinformation, and mal-information to rise to the level of terrorism, little is known about service members' experiences with disinformation in the military context. We examined soldiers' perceptions of disinformation impact on the Army and their units. We also investigated associations between disinformation perceptions and soldiers' sociodemographic characteristics, reported use of fact-checking, and perceptions of unit cohesion and readiness.

View Article and Find Full Text PDF

Aims: Inactivation processes using heat are widely used for disinfection and sterilization. Dry heat sterilization of spacecraft equipment has been the preferred microbial inactivation method as part of interplanetary travel protection strategies. An antimicrobial model, based on temperature and exposure time based on experimental data, was developed to provide reliable sterilization processes to be used for interplanetary applications.

View Article and Find Full Text PDF

In the design, control, and regulation of the manufacturing and supply of microbiologically controlled devices (including sterile devices) and drug products (including cleaning, disinfection, and sterilization processing and/or aseptic process manufacturing), different terms and/or definitions are often used internationally for similar processes or applications. With product innovations (including combination products and cell-based therapy) and global regulatory influences, there is a growing need to harmonize these definitions. The objective of the Kilmer Regulatory Innovation microbiological quality and sterility assurance glossary is to clarify and harmonize the practical use of terms employed by the different parts of regulated health care product industries internationally and by regulators of the manufacturing and supply of microbiologically controlled health care products internationally.

View Article and Find Full Text PDF

Cleaning chemistries are detergent-based formulations that are used during the processing of reusable medical devices. Manufacturers are responsible for demonstrating the safety of cleaning formulations when they are used during a device processing cycle, including the risk of device-associated cytotoxicity over the concentration ranges for recommended use and rinsing during cleaning. However, no regulation currently exists requiring manufacturers to demonstrate such safety.

View Article and Find Full Text PDF

In the design, control, and regulation of the manufacturing and supply of microbiologically controlled devices (including sterile devices) and drug products (including cleaning, disinfection, and sterilization processing and/or aseptic process manufacturing), different terms and/or definitions are often used for similar processes or applications internationally. With product innovations (including combination products and cell-based therapy) and global regulatory influences, there is a growing need to harmonize these definitions. The objective of the Kilmer Regulatory Innovation microbiological quality and sterility assurance glossary is to clarify and harmonize the practical use of terms employed by the different parts of regulated healthcare product industries internationally and by regulators of the manufacturing and supply of microbiologically controlled healthcare products internationally.

View Article and Find Full Text PDF

Validating a thermal disinfection process for the processing of medical devices using moist heat via direct temperature monitoring is a conservative approach and has been established as the A0 method. Traditional use of disinfection challenge microorganisms and testing techniques, although widely used and applicable for chemical disinfection studies, do not provide as robust a challenge for testing the efficacy of a thermal disinfection process. Considerable research has been established in the literature to demonstrate the relationship between the thermal resistance of microorganisms to inactivation and the A0 method formula.

View Article and Find Full Text PDF

When investing in X-ray irradiation facilities around the world, an opportunity exists for defining a regulatory framework for assessing the transition from current gamma irradiation processes. Historically, regulatory strategies for changing the radiation source for routine processing has consisted of repeating the majority, if not all, of the validation activities performed as part of an initial validation and associated submission. Although not a new concept, performing a risk assessment has the potential to be leveraged more fully by increasing the rigor of determining what is changing when product moves from a gamma to an X-ray irradiator, then determining how these differences may affect product characteristics.

View Article and Find Full Text PDF

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages.

View Article and Find Full Text PDF

Moist heat is employed in the medical device, pharmaceutical, and food processing industries to render products and goods safe for use and human consumption. Applications include its use to pasteurize a broad range of foods and beverages, the control of microbial contamination of blood products, and treatment of bone tissue transplants and vaccines. In the pharmaceutical industry, water heated to 65°C to 80°C is used to sanitize high-purity water systems.

View Article and Find Full Text PDF

Background: A troubling number of health care-acquired infection outbreaks and transmission events, some involving highly resistant microbial pathogens and resulting in serious patient outcomes, have been traced to reusable, high-level disinfected duodenoscopes in the United States. The Food and Drug Administration (FDA) requested a study be conducted to verify liquid chemical sterilization efficacy of SYSTEM 1E(®) Liquid Chemical Sterilant Processing System (STERIS Corporation, Mentor, OH) with varied duodenoscope designs under especially arduous conditions. Here, we describe the system's performance under worst case SYSTEM 1E(®) processing conditions.

View Article and Find Full Text PDF

There is still great interest in controlling bacterial endospores. The use of chemical disinfectants and, notably, oxidizing agents to sterilize medical devices is increasing. With this in mind, hydrogen peroxide (H2O2) and peracetic acid (PAA) have been used in combination, but until now there has been no explanation for the observed increase in sporicidal activity.

View Article and Find Full Text PDF

Inadequate flexible endoscope reprocessing has been associated with infection outbreaks, most recently caused by carbapenem-resistant Enterobacteriaceae. Lapses in essential device reprocessing steps such as cleaning, disinfection/sterilization, and storage have been reported, but some outbreaks have occurred despite claimed adherence to established guidelines. Recommended changes in these guidelines include the use of sterilization instead of high-level disinfection or the use of routine microbial culturing to monitor efficacy of reprocessing.

View Article and Find Full Text PDF

Reusable devices are required to be safety processed prior to patient use, including cleaning and disinfection and sterilization. In developing and testing cleaning processes, it is important to understand the levels of soils typically present on devices after surgical use. Previous soil investigations have focused on microbial contamination levels; less is known about biochemical contamination.

View Article and Find Full Text PDF

Leprosy is a curable neglected disease of humans caused by Mycobacterium leprae that affects the skin and peripheral nerves and manifests clinically in various forms ranging from self-resolving, tuberculoid leprosy to lepromatous leprosy having significant pathology with ensuing disfiguration disability and social stigma. Despite the global success of multi-drug therapy (MDT), incidences of clinical leprosy have been observed in individuals with no apparent exposure to other cases, suggestive of possible non-human sources of the bacteria. In this study we show that common free-living amoebae (FLA) can phagocytose M.

View Article and Find Full Text PDF

Objectives: To elucidate the mechanisms of spore resistance to and killing by the oxidizing microbicide peracetic acid (PAA).

Methods: Mutants of Bacillus subtilis lacking specific spore structures were used to identify resistance properties in spores and to understand the mechanism of action of PAA. We also assessed the effect of PAA treatment on a number of spore properties including heat tolerance, membrane integrity and germination.

View Article and Find Full Text PDF

Individuals are highly sensitive to statistical regularities in their visual environment, even when these patterns do not reach conscious awareness. Here, we examine whether oculomotor behavior is systematically altered when distractor/target configurations rarely repeat, but target location on an initial trial predicts the location of a target on the subsequent trial. The purpose of the current study was to explore whether this temporal-spatial contextual cueing in a conjunction search task influences both reaction time to the target and participant's search strategy.

View Article and Find Full Text PDF

The present study examined the influence of holding task-relevant gaze cues in working memory during a target detection task. Gaze cues shift attention in gaze-consistent directions, even when they are irrelevant to a primary detection task. It is unclear, however, whether gaze cues need to be perceived online to elicit these effects, or how these effects may be moderated if the gaze cues are relevant to a secondary task.

View Article and Find Full Text PDF

The incidence of lung and other diseases due to nontuberculous mycobacteria (NTM) is increasing. NTM sources include potable water, especially in households where NTM populate pipes, taps, and showerheads. NTM share habitats with free-living amoebae (FLA) and can grow in FLA as parasites or as endosymbionts.

View Article and Find Full Text PDF