Infections that develop in the hospital
- Infections that have been caught in the hospital setting and are potentially caused by organism that are resistant to antibiotics.
- Pseudomonas aeruginosa
- E. coli
Healthcare associated infections
- Refers to infections that develop in a patients during the course of medical treatment.
- There are unique risks for HAIs: endotracheal tube, central venous catheter.
- HAIs can also be related to pathogens that are more likely to be resistant to one or more classes of antimicrobial agents.
- Example: Pseudomonas aeruginosa
- Vector-borne transmission of infectious diseases from insects and rates and other vermin occurs but is of less significance in the US health care facilities.
- Ticks and mites:
- Lyme disease
- Common vehicle transmission via exposure to pathogens in contaminated food, water or medications (i.e. heparin solution)
- Water borne:
- Food borne:
- Hep A
- Inanimate objects that may serve to transfer pathogens from one person to another are called fomites.
- Indirect contact transmission involving fomites can occur when instruments have been inadequately cleaned between patients before disinfection or sterilization.
Factors that aide in the spread of infection
A source (or reservoir) of pathogens
- A route of transmission for the pathogen
- A susceptible host
- Source of infectious agents
- Humans are the primary source for infectious agents in the health care setting; but inanimate objects (contaminated medical equipment, linen, medications) have also been implicated in transmission.
- Susceptible host
- Susceptibility and resistance to infection vary greatly, and host factors in the acute setting that predispose to HAI can be considered modifiable and nonmodifiable.
- Host factors such as: diabetes mellitus, extremes of age, and underlying acquired (HIV) or iatrogenic (chemotherapy/anti-tumor necrosis factor inhibitors) immunodeficiency, can enhance susceptibility to infection and are not readily modifiable in the acute setting.
- Modes of transmission
- Three major modes of transmission:
- Respiratory droplet
- 1)Droplet transmission is a form of contact transmission, but the mechanism of transfer of the pathogen is distinct and additional prevention measures are required.
- 2)Organism transmitted by droplet include:
- Neiseria meningitis
- 3)Respiratory droplets are generated when an infected individual discharges large contaminated liquid droplets into the air by:
- Cough induction
- Transmission occurs when infectious droplets are propelled ( <3 feet) into the air and are deposited on another person mouth or nose.
- Airborne droplet nuclei
- 1)These are small particles of evaporated droplets containing infectious microorganisms that can remain suspended in air for long periods.
- 2)Microorganism carried in this manner can be dispersed widely by air currents because of their small size and inhaled by susceptible hosts over longer distance from source patient compared with droplet transmission.
- Examples include:
- Mycobacterium tuberculosis
- Varicella- zoster virus
- Rubeola virus
- Occurs when pathogen is transmitted directly form one person to another.
- Direct contact occurs less frequently that indirect
- Most frequent mode of transmission in the health care environment
- Involves transmission of a pathogen through a contaminated intermediate object or personMost common indirect contact transmission in health care involves unwashed hands of health care personnel that touch an infected or a colonized body site on one patient, or a contaminated inanimate object, and subsequently touch another patient.
- Steam autoclaving (Very high temperatures and pressures)
- Moist heat in the form of steam under pressure is the most common, most efficient, and easiest sterilization process.
- Steam sterilization is the application of steam under high pressure.
- Steam sterilization is quick, cheap, clean and reliable.
- Equipment must always be thoroughly cleaned before sterilization because materials that remain on the surface =s of equipment interfere with the effectiveness of the sterilization process.
- Clean equipment wrapped in muslin, linen, or paper or placed in specially designed rigid containers.
- The higher the temperature and pressure of the sterilizer, the shorter the time needed for sterilization.
- The combination most commonly used for autoclaving is 15 psi and 121*C for a minimum of 30 minutes
- Gas sterilization- ETO (Ethylene Oxide)
Low-Temperature Sterilization technologies
-Less than <60 C
-ETO, hydrogen peroxide gas plasma, ozone, vaporized hydrogen peroxide, and peracetic acid (Good sterilant for items that cannot be autoclaved)
- EtO is a colorless, toxic gas and potent sterilizing agent
- Because it is active at ambient temperatures and is harmless to rubber and plastics, EtO is a good sterilant for items that cannot be autoclaved.
- EtO penetrates most packing material, permitting prewrapping.
- EtO would be the ideal sterilant if it weren’t for its many hazards.
- Acute exposure to EtO:
- Airway inflammation
- Chronic Expsoure:
- Respiratory infections
- Altered nehavior
- Residual EtO left on processed equipment can cause:
- Tissue inflammation
- When combined with water EtO forms ethylene glycol which also irritates tissue
- Other potential problems include:
- Teratogenic effects
- EtO concentrations greater that 3% are explosive
- Residual EtO must be removed from equipment after sterilization via a process called aeration.
- EtO is used to sterilize critical and semi critical items
- Home cleaning of respiratory equipment: Acetic Acid (Vinegar)
Is the first step in all equipment processing
-Removes dirt and organic material
Isolation: (types) – Types of PPE to wear
- • Airborne (respiratory)
- -Use of N-95 respirator
- -Hand hygene
- -Standard precautions
- o In addition to airborne infection isolation room, personal respiratory protection with National Institute for Occupational Safety and Health (NIOSHA)- approved N-95 or higher respirators is required to prevent airborne transmission
- • Droplet
- a. Perform hand hygiene
- b. Surgical mask
- i. Droplet precaution is for patients with presumed or confirmed infection with organisms known to be transmitted by respiratory droplets such as influenza
- c. Standard precautions
- • Contact
- a. Contact precautions are intended to reduce the risk for transmission by direct or indirect contact with the patient or the patients environment.
- i. PPE includes:
- 1. Gowns
- 2. Gloves
- • Contact enhanced
- a. Gowns
- b. Gloves
- c. N-95
- d. Eye protection
- i. C. difficile is a illness that requires contact enhanced
- e. Standard precautions
- • Reverse
- Gown, gloves, mask, etc. Standard precautions
- a. When the patient is in an immunocompromised state and needs to be in a protected envioronment
- i. PPE:
- 1. Gloves
- 2. Mask
- b. Room should have:
- i. High efficiency particulate air filtration of incoming air
- ii. Directed room airflow
- iii. Positive room air pressure relative to the corridor
- iv. Well-sealed rooms to prevent infiltration of outside air
- v. Ventilation to provide 12 or more air changes per hour
- vi. Strategies to reduce dust
- vii. Prohibition of dried and fresh flowers and potted plants in room