Question

Summary of diseases transmitted through disinfection and sterilization, with statistics and studies provided for some countries

Answer 1

Sterilization describes a process that destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods. Steam under pressure, dry heat, EtO gas, hydrogen peroxide gas plasma, and liquid chemicals are the principal sterilizing agents used in health-care facilities. Sterilization is intended to convey an absolute meaning; unfortunately, however, some health professionals and the technical and commercial literature refer to “disinfection” as “sterilization” and items as “partially sterile.” When chemicals are used to destroy all forms of microbiologic life, they can be called chemical sterilants. These same germicides used for shorter exposure periods also can be part of the disinfection process (i.e., high-level disinfection). Sterilization can be achieved by a combination of heat, chemicals, irradiation, high pressure and filtration like steam under pressure, dry heat, ultraviolet radiation, gas vapor sterilants, chlorine dioxide gas etc

Disinfection describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects (Tables 1 and 2). In health-care settings, objects usually are disinfected by liquid chemicals or wet pasteurization. Each of the various factors that affect the efficacy of disinfection can nullify or limit the efficacy of the process.

This leads to entrance of bacteria adhered on surgical and medical equipment or devices to sterile tissues of patient as a result of infection. Not only contaminated surgical and medical equipment are risk factors for infection but also contaminated common areas used by community such as toilets, public transport vehicles and door handles and contaminated air causing transmission of pathogens from person to person and contaminated kitchen equipment causing cross contamination between equipment and foods are risk factors for health-threatening infections. Inadequate disinfections of these equipment and air are risk factors for transmission of pathogens to patients. Hepatitis B, hepatitis C, Rota virus, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli O157:H7, Salmonella typhimurium, Shigella dysenteriae, Vibrio cholera, and Helicobacter pylori are the most common examples of pathogens transmitted. Failure to apply disinfection applications has been leading to various outbreaks

Factors that affect the efficacy of both disinfection and sterilization include prior cleaning of the object; organic and inorganic load present; type and level of microbial contamination; concentration of and exposure time to the germicide; physical nature of the object (e.g., crevices, hinges, and lumens); presence of biofilms; temperature and pH of the disinfection process; and in some cases, relative humidity of the sterilization process (e.g., ethylene oxide).

Unlike sterilization, disinfection is not sporicidal. A few disinfectants will kill spores with prolonged exposure times (3–12 hours); these are called chemical sterilants. At similar concentrations but with shorter exposure periods (e.g., 20 minutes for 2% glutaraldehyde), these same disinfectants will kill all microorganisms except large numbers of bacterial spores; they are called high-level disinfectants. Low-level disinfectants can kill most vegetative bacteria, some fungi, and some viruses in a practical period of time (≤10 minutes). Intermediate-level disinfectants might be cidal for mycobacteria, vegetative bacteria, most viruses, and most fungi but do not necessarily kill bacterial spores. Germicides differ markedly, primarily in their antimicrobial spectrum and rapidity of action.