Chain of Infection

• A safe working environment should be maintained in a healthcare setting. This prevents infection when a microorganism enters and multiplies in or on a host.
• Infections that may be obtained include but are not limited to nosocomial infection, community-acquired infection, local infection, and systemic infection.
• A nosocomial infection is hospital-acquired. Its signs and symptoms develop 48 hours or more after admission, hospital visit, or within 30 days after discharge from a hospital or healthcare facility.
• A community-acquired infection is obtained before admission.
• a systemic infection involves the entire body.
• local infection is restricted to one body area
• The chain of infection is how microorganisms are

  transmitted. It is a continuous link between a

  source, a transmission mode, and a susceptible host
• These three factors are connected by two portals: a portal of exit from the source and a portal of entry into the host.
• The source of an infection includes infected people, specimens, and other contaminated materials. Microorganisms from the source are transmitted to the host.
• The mode of transmission can be direct or indirect. 
• Direct transmission includes horizontal transmission, such as hand-to-hand contact, animal contact, and sexual intercourse, and vertical transmission, such as mother to fetus or newborn
• Indirect transmission includes the transfer of microorganisms through fomites, food, water, aerosols, and vectors
• DIRECT CONTACT- Physical transfer of infectious microorganisms from the source to susceptible host
• Horizontal transmission- Hand-to-hand transmission, Sexual contact, Respiratory droplet transmission (droplets that travel 1 meter or less from infected individual;

  coughing, sneezing, talking)
• Vertical transmission- Congenital transmission (occurs across the placenta or as the baby passes through the vaginal canal during delivery)
• INDIRECT CONTACT- Transfer of infective material via an object
• Fomites- Inanimate objects (eating utensils, drinking cups, water bottles, hospital instruments, clothing, money, doorknobs, and tampons)
• Vehicle Transmission- Ingestion of contaminated food, Intake of contaminated water, Inhalation of infectious aerosols
• Vector transmission- Mechanical vectors and Biological vectors (insects or arthropods)
• The microorganisms enter the host through different portals of entry, such as the mucous membrane, gastrointestinal tract, respiratory tract, and broken skin.
• The key to the infection concept is that the host must be susceptible to the infecting organism.
• The host's susceptibility is often affected by different factors such as age, disease, medication, and immunosuppressive agents.
• Breaking the chain of infection should be of primary goal of healthcare institutions.
• Procedures and interventions should be done, such as adequate hand hygiene, good nutrition, immunization, insect and pest control, isolation and decontamination, use of proper safety devices, use of personal protective equipment (PPE), and proper disposal of sharps and waste materials.
• Healthcare institutions should have an Infection-Control Program. This program has the following functions:

  1. To protect patients, employees, and visitors from infection
  2. To screen employees for infectious diseases and require immunization when needed
  3. To provide evaluation and treatment to health workers who were exposed to infections while performing their duties, and
  4. To monitor employees and patients who are at risk of infection and collect data from patients and health workers who were exposed to such.
• Infection- The state produced by the establishment of one or more pathogenic agents (such as a bacteria, protozoans, or viruses) in or on the body of a suitable host
• INFECTION CONTROL- Prevents or stops the spread of infections in healthcare settings