Decontamination in Hospitals and Healthcare

James T. Walker

• Éditeur: Woodhead Publishing
• Année: 2014
• ISBN:
  9780857096692
• Sujet: Tecnología e ingeniería
• Sous-sujet: Gestión medioambiental

Decontamination in Hospitals and Healthcare brings an understanding of decontamination practices and the development of technologies for cleaning and control of infection to a wide audience interested in public health, including healthcare specialists, scientists, students or patients.

Part one highlights the importance and history of decontamination in hospitals and healthcare before exploring the role of standards in decontamination, infection control in Europe, and future trends in the area. Part two focuses on decontamination practices in hospitals and healthcare. It considers the role of the nurse in decontamination, the issues of microbial biofilm in waterlines, control of waterborne microorganisms, and the use of gaseous decontamination technologies. Further chapters explore decontamination of prions, the use of protective clothing, no-touch automated room disinfection systems, and controlling the presence of microorganisms in hospitals. Part three discusses practices for decontamination and sterilization of surgical instruments and endoscopes. These chapters examine a range of guidance documents, including the choice framework for local policy and procedures for decontamination of surgical instruments, as well as novel technologies for cleaning and detection of contamination.

Decontamination in Hospitals and Healthcare provides a reference source on decontamination for public health professionals and students concerned with healthcare. It is particularly useful for scientists in microbiology and disinfection/decontamination laboratories, healthcare workers who use disinfectants, students in microbiology, clinicians, members of the Institute of Decontamination Sciences/Central Sterilising Club, and those employed in the Central Sterile Services departments of healthcare facilities.

• Discusses decontamination processes in Europe
• Provides an in-depth understanding into decontamination in healthcare settings, specifically hospitals and dental practices
• Examines the decontamination of surgical equipment and endoscopes

Part I

Fundamentals of decontamination in hospitals and healthcare

1

The importance of decontamination in hospitals and healthcare*

J.T. Walker Public Health England, UK

Abstract

Decontamination and disinfection are important in hospitals to control healthcare-acquired infections (HAI). Historically, Alexander Gordon, Ignaz Semmelweis and Florence Nightingale recognised the importance of hand washing and cleanliness. Meticillin resistant Staphylococcus aureus (MRSA) and Clostridium difficile cause thousands of fatalities per year but recent Department of Health (England) programmes in the last decade have reduced HAI rates. The emergence of variant Creutzfeldt–Jacob Disease (vCJD) prompted a reappraisal of the treatment of surgical instruments in contact with high risk tissues to prevent further human to human transmission. Prions demonstrate that there are still major challenges in the world of disinfection and decontamination and as healthcare professionals it is our duty to remain vigilant against future disease threats.

Key words

decontamination

disinfection

central sterile services department

endoscopes

surgical instruments

dental decontamination

Creutzfeldt–Jakob disease (CJD)

1.1 Introduction

Decontamination and disinfection mean different things to different people. Patients enter a hospital or healthcare environment to have one particular ailment treated and all health professionals undertake their roles to ensure that patients depart hospitals with their illnesses treated and/or progressing towards good health. To this end there are multiple protocols, guidance documents and standards in place to protect the patient and prevent them from being harmed during their stay in hospital. However, hospital-acquired infections are a constant part of our everyday life in the healthcare sector and account for many deaths and increased costs (1, 2). As healthcare professionals, healthcare-acquired infection (HAI) should not be acceptable, and as such, multiple targets are set to monitor HAI rates and hospitals are judged by their achievements in reducing these rates.

Historically, surgeons, clinicians and nursing professionals have recognised the risk to patients from the presence of microorganisms that are ubiquitous in our healthcare centres. The programmes in place today that reinforce hand hygiene policies, such as the WHO's five (3) principles in hand washing, owe their validity to Alexander Gordon (4) and Ignaz Semmelweis (5), with the latter recommending that all staff and students wash their hands in ‘chlorina liquida’ (known to be a disinfectant), later changing to the cheaper ‘chloride of lime’. First discovered in 1744 and still widely used today, chlorine, as a disinfectant, was listed in the London Pharmacopeia (1836) and recommended as a gargle for infected throats (6) before being used by Semmelweis for the routine disinfection of hands in his study in the prevention of puerperal fever in maternity wards (5). By the 1880 s Koch had recognised the importance of disinfectants as well as the susceptibility of different microorganisms to different active agents when he studied over 70 compounds and declared mercuric chloride as the most effective product as it was effective against spores (7).

However, what we have to take into consideration is that the healthcare environment is not sterile and that ‘disinfection and decontamination’ of the environment, ward or hospital theatre reduces microorganisms to a safe level leading to improved HAI rates. Florence Nightingale recognised the importance of ‘clean and dry bed and bedding’ as well as ‘cleanliness of room and walls’ and this facet of improving cleanliness around the patient and reducing the presence of microorganisms (i.e. cleaning and decontamination) would have improved the well-being of the patient (8). In contrast, ‘sterilisation’ of medical devices or surgical instruments is the absolute removal of microorganisms ensuring that the device is safe to use on a patient. Sterilisation is an absolute term for destruction of bacteria, spores and viruses and all living microorganisms.

However, the discovery of prions and their survival, following autoclaving, in sufficient concentrations to cause disease via surgical instrumentation has led to a re-evaluation of cleaning, disinfection and sterilisation across the whole sector of patient care (9).

1.2 Microbial resistance and infection control

Microorganisms differ in their susceptibilities to disinfectants, with vegetative bacteria being the most sensitive and spores being the most resistant, though prions are more resistant than spores (Table 1.1). In the 1960s, Spaulding's approach to disinfection and sterilisation of medical devices was based on the categorisation of critical (enter sterile tissue), semi-critical (contact mucous membranes or non-intact skin) and non-critical devices (contact with intact skin but not mucous membranes), which was dependent on the degree of infection risk associated with the use of particular items (10).

Table 1.1

Susceptibility of different types of microorganisms to decontamination

Resistance	Microorganisms
Very resistant	Prions
More resistant	Bacterial spores
Less sensitive	Mycobacteria, protozoal cysts and non-enveloped viruses (Polis, Hep A)
Most sensitive	Vegetative bacteria, enveloped viruses (HIV, RSV, Hep B), fungi (and their spores), non-encysted protozoa

Infection control, contamination of wards and the environment, as well as operating theatres, have been at the forefront of infection control policies for many years. However, the decontamination and sterilisation of surgical instruments has for some time been treated as the Cinderella of healthcare, e.g. often located in the basements in an out-of-sight, out-of-mind scenario.

Whilst biocides and disinfectants have been discovered and developed for the decontamination of bacteria and viruses, it was the development of the autoclave that provided the assurance that the risk of transmission of bacteria and viruses was ultimately controlled through the use of heat and pressure. The first publication on the development of the autoclave appeared in 1681 as a digester for softening bones and in the 1830 s it was further developed for the control of fomites (11, 12) from infected persons. Research by Koch (1881) that identified that moist heat was more effective than dry heat led to the autoclaves that were later developed for clinical use (13).

Sterilisation via autoclaving was deemed to be a fail-safe mechanism of providing medical and surgical devices that would be microbiologically safe to use. Whilst there have been failures in the autoclaves or associated process, these have been rare (14–16), resulting in patients becoming infected, a properly and effectively validated steriliser will achieve a 10⁶ log reduction of microorganisms.

Today, there are major issues concerning the transmission of HAI in a modern healthcare setting. These issues include the emergence of antibiotic resistant microorganisms (17, 18). Antibiotics were initially seen as the major weapon in the fight against microbial infections and, in many cases, still are, and are able to prevent many deaths through the control of those infections. Yet in developed countries antibiotic resistance is such an issue that many microorganisms are multidrug resistant and hence difficult to treat. Whilst some microorganisms can be naturally susceptible to antibiotics, problems occur both for patients and clinicians where microorganisms that were susceptible to antibiotics become resistant, often to the transfer of resistance genes from one microbial host (resistant) to a microbial recipient (was susceptible and will become resistant) (19, 20).

HAI rates are now collected and reported regularly, e.g. quarterly and annually, are publically available and are compared against other time points and against different trusts. HAI numbers have ...