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10.4D: Control of Nosocomial Infections

  • Page ID
    11701
  • LEARNING OBJECTIVES

    • Give examples of ways nosocomial infections can be controlled or prevented

    Hospitals have sanitation protocols regarding uniforms, equipment sterilization, washing, and other preventive measures. Thorough hand washing and/or the use of alcohol rubs by all medical personnel before and after each patient contact is one of the most effective ways to combat nosocomial infections. More careful use of antimicrobial agents, such as antibiotics, is also considered vital.

    Despite sanitation protocol, patients cannot be entirely isolated from infectious agents. Furthermore, patients are often prescribed antibiotics and other antimicrobial drugs to help treat illness; this may increase the selection pressure for the emergence of resistant strains. Sterilization goes further than just sanitizing. It kills all microorganisms on equipment and surfaces through exposure to chemicals, ionizing radiation, dry heat, or steam under pressure. Isolation precautions are designed to prevent transmission of microorganisms by common routes in hospitals. Because agent and host factors are more difficult to control, interruption of transfer of microorganisms is directed primarily at transmission.

    The Importance of Handwashing

    Handwashing is the single most important measure to reduce the risks of transmitting skin microorganisms from one person to another or from one site to another on the same patient. Washing hands as promptly and thoroughly as possible between patient contacts and after contact with blood, body fluids, secretions, excretions, and equipment or articles contaminated by them is an important component of infection control and isolation precautions.

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    Figure: Hand washing with soap: Handwashing is the single most important measure to reduce the risks of transmitting skin microorganisms from one person to another or from one site to another on the same patient.

    The spread of nosocomial infections among immunocompromised patients is connected with health care workers’ hand contamination in almost 40% of cases. This presents a challenging problem in the modern hospitals. The best way for workers to overcome this problem is by conducting correct hand- hygiene procedures; this is why in 2005 the WHO launched the GLOBAL Patient Safety Challenge.

    Two categories of micro-organisms can be present on health care workers’ hands: transient flora and resident flora. The first is represented by the micro-organisms taken by workers from the environment, and the bacteria in it. These are often capable of surviving on the human skin and sometimes to grow. The second group is represented by the permanent micro-organisms living on the skin surface, on the stratum corneum or immediately under it. They are capable of surviving on the human skin and of growing freely on it. They have low pathogenicity and infection rate, and they create a kind of protection from the colonization from other more pathogenic bacteria.

    The skin of workers is colonized by 3.9 x 104 – 4.6 x 106 cfu/cm2. The microbes comprising the resident flora are: Staphylococcus epidermidis, S. hominis, and Microccocus, Propionibacterium, Corynebacterium, Dermobacterium, and Pitosporum spp., while in the transitional could be found S. aureus, and Klebsiella pneumoniae, and Acinetobacter, Enterobacter and Candida spp. The goal of hand hygiene is to eliminate the transient flora with a careful and proper performance of hand washing, using different kinds of soap, both normal and antiseptic, and alcohol-based gels. The main problems found in the practice of hand hygiene are connected with the lack of available sinks and the time-consuming performance of hand washing. An easy way to resolve this problem could be the use of alcohol-based hand rubs, because of faster application compared to correct hand washing.

    The Second Line of Defense: Gloves

    Gloves play an important role in reducing the risks of transmission of microorganisms. Gloves are worn for three important reasons in hospitals.

    • They are worn to provide a protective barrier and to prevent gross contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes, and non-intact skin. In the USA, the Occupational Safety and Health Administration (OSHA) has mandated wearing gloves to reduce the risk of blood-borne pathogen infections.
    • Gloves are worn to reduce the likelihood microorganisms present on the hands of personnel will be transmitted to patients during invasive or other patient-care procedures that involve touching a patient’s mucous membranes and nonintact skin.
    • They are worn to reduce the likelihood the hands of personnel contaminated with micro-organisms from a patient or a fomite (contaminated object) can be transmitted to another patient. In this situation, gloves must be changed between patient contacts, and hands should be washed after gloves are removed.

    Surfaces

    Sanitizing surfaces is an often overlooked, yet crucial, component of the strategy for the cycle of infection in health care environments. Modern sanitizing methods such as NAV-CO2 have been effective against gastroenteritis, MRSA, and influenza agents. Use of hydrogen peroxide vapor has been clinically proven to reduce infection rates and risk of acquisition. Hydrogen peroxide is effective against endospore-forming bacteria, such as Clostridium difficile, where alcohol has been shown to be ineffective.

    Microorganisms are known to survive on inanimate “touch” surfaces for extended periods of time. This can be especially troublesome in hospital environments, where patients with immunodeficiencies are at enhanced risk for contracting nosocomial infections.

    Wearing an apron during patient care reduces the risk of infection. The apron should either be disposable or be used only when caring for a specific patient.

    Key Points

    • Handwashing frequently is called the single most important measure to reduce the risks of transmitting skin microorganisms from one person to another or from one site to another on the same patient.
    • Thorough hand washing and/or use of alcohol rubs by all medical personnel before and after each patient contact is one of the most effective ways to combat nosocomial infections.
    • Sanitizing surfaces is an often overlooked, yet crucial, component of breaking the cycle of infection in health care environments.

    Key Terms

    • sterilization: Any process that eliminates or kills all forms of microbial life present on a surface, solution, or solid compound.
    • nosocomial: contracted in a hospital, or arising from hospital treatment
    • sanitation: The policy and practice of protecting health through hygienic measures.

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