Nurse Aide Increased Infection Control
Module 1: Introduction to Pathogens

Thank you for Joining Us


Welcome to Module 1: Introduction to Pathogens. We are glad you're here!

What you learn in this class will help keep you, and your residents, safe. 

Module 1 will present a broad overview of pathogenic organisms.



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Order of Modules

This course is designed to increase your infection control knowledge in long-term care environments. Information from this CBT can be directly applied to your daily activities as a nurse aide.


This course has five modules. You must save or print the certificate at the end of each module. Keep these certificates as proof of completion.

  • Module 1: Introduction to Pathogens
  • Module 2: Chain of Infection/Modes of Transmission
  • Module 3: PPE
  • Module 4: Standard and Transmission-based Precautions
  • Module 5: Cleaning and Disinfection


There is no way to create a lost certificate of completion without taking or retaking the course. If you do not keep a copy for your records, you will need to repeat this course.


Let's get started!



Lesson Objectives


In this CBT, you will:


  • Discuss different pathogen types;


  • Identify the most common communicable disease types seen in a long-term care setting; and


  • Demonstrate your understanding of pathogens.




Introduction to Pathogens


In a long-term care environment, it is likely that you will encounter illnesses in residents.


These illnesses may be caused by various pathogens and may be transmissible to yourself and other residents.


Understanding what different pathogens may cause, and how they act, will allow you to care for your residents in the best possible manner.


There are many types of pathogens that may be found in a long-term care setting, though some are more common than others.



Communicable Disease

A communicable disease is one that is transmissible from person-to-person, animal-to-person (zoonotic disease), or object-to-person.


Many of the illnesses present in long-term care facilities are caused by communicable disease. Not only do these illnesses pose a threat to the resident population, there is a risk of caregivers (like yourself) contracting the illness as well


Healthcare-Associated Infections | HAI

In a long-term care setting, many of the treatment options for diseases and disorders will use invasive devices, like central-lines, catheters, or even ventilators.


Sometimes, these invasive devices can become infected. These healthcare-associated infections (HAIs) include central line-associated bloodstream infections, catheter-associated urinary tract infections, and ventilator-associated pneumonia. Infections may also occur at surgery sites, known as surgical site infections. 


For more information on this topic, visit the CDC .




Bacteria are single-celled organisms that live in our environment. It is estimated that up to 3% of a person's body weight can be attributed to the bacteria in and on their bodies. That is 6 pounds of bacteria in and on a 200-pound person!


Bacteria can be beneficial for our health and well-being. They can also be extremely harmful in a vulnerable population, such as a geriatric group.

Many of the infections that you will see in a long-term care facility are caused by bacteria. A few examples include:

  • Pneumonia
  • Urinary Tract Infections (UTI)
  • Cellulitis
  • Skin and soft-tissue infections


These can usually be treated easily with antibiotics, through a few (like Methicillin-Resistant Staphylococcus aureus, known as MRSA, and Vancomycin-Resistant Enterococcus, or VRE) are much harder to treat and can have dire consequences.




 Common Bacteria in Geriatric Communities: Salmonella Poisoning

Salmonella enterica is a bacterium that commonly causes food poisoning. This bacterium colonizes in the intestinal tract and can cause nausea, diarrhea, cramps, fever, chills, and occasionally blood in the stool.


Salmonella is generally spread by ingesting unpasteurized or raw eggs and raw milk, and raw meat (including chicken) with symptoms appearing from 8-72 hours after ingestion.


Treatment for salmonella is generally rest and an increase in fluid intake. Antibiotics are not generally recommended for food poisoning, through extreme cases of vomiting or diarrhea may require IV fluids to prevent complications from dehydration.


Occasionally, salmonella can enter the bloodstream of an infected individual and can cause bacteriemia. This condition can be dangerous and may cause meningitis if the bacteria colonizes the brain and spinal cord or endocarditis if the bacteria colonizes your heart or heart valves. In these cases, prompt medical attention is required.



Common Bacteria in Geriatric Communities: Tuberculosis

Tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis. It is generally thought to attack the lungs, though cases of bacterial colonization in the brain, kidneys, and spine have been reported.


A tuberculosis infection may not always present as symptomatic. This is known as a latent TB infection.


Because TB can be common in congregate settings, or places where many people live together, it is important to identify changes in the resident that might result from a TB infection.


Symptomatic cases of TB will usually present with:

  • a bad cough that lasts 3 weeks or longer
  • pain in the chest
  • coughing up blood or sputum (phlegm from deep inside the lungs)
  • In addition, patients may have fever, chills, night sweats, weakness/fatigue, unexplained weight loss and appetite loss.


 TB is usually treated with a course of antibiotic over 6-9 months. Most infections are recoverable, but advanced or drug-resistant cases can be fatal.


Common Bacteria in Geriatric Communities: Group A Streptococcus

The bacterium called group A  Streptococcus can cause a host of different illnesses, depending on areas of colonization. These illnesses include:

  • Strep Throat
  • Impetigo
  • Cellulitis
  • Necrotizing Fasciitis
  • Rheumatic Fever
  • Toxic Shock Syndrome

Symptoms of a group A Streptococcal infection will vary based on the area of colonization. Treatments will generally include a course of antibiotics. The severity and location of the infection will determine the treatment regimen.




Common Bacteria in Geriatric Communities: Clostridium difficile

Clostridiodes difficile (sometimes known as Clostridum difficile) is a bacterium that causes diarrhea and colitis. Most C. diff infections occur after someone has completed a round of antibiotics for an unrelated infection.


According to the CDC, once someone is diagnosed with a C. diff infection about 1 in 6 patients will get it again in the subsequent 2-8 weeks.

Within a month of diagnosis,  1 in 11 people over age 65  died of a healthcare-associated  C. diff  infection.


Symptoms of C. diff include:

  • Diarrhea including loose, watery stools (poop) or frequent bowel movements for several days
  • Fever
  • Stomach tenderness or pain
  • Loss of appetite
  • Nausea


Treatment of a C. diff infection is a course of strong antibiotics.


It is important to note that caregivers, as well as the infected individual, must wash their hands frequently with soap and water. Alcohol Based Hand Rubs are NOT effective against this bacterium.











Viruses are non-living organisms that depend on a host for survival. While a virus can "survive" for an extended period outside of a host, it does not possess some of the characteristics required to be considered living.


Viral illnesses have a wide range of symptoms and severity. There are many different types of illnesses found in long-term care settings that are caused by viruses.


These illnesses include:

  • Influenza
  • SARS-CoV-2 (COVID-19)
  • Norovirus gastroenteritis
  • Common colds (caused by a variety of different viruses)


It is extremely important to note that antibiotics are not an effective treatment for viral infections. Antibiotics DO NOT kill viruses. The use of antibiotics when there is not a bacterial infection can lead to multi-drug resistant infections.



Common Viruses in Geriatric Communities: Influenza

The flu is caused by a group of influenza viruses that target the respiratory systems of infected individuals.


Symptoms of the flu include:

  • Fever or feeling feverish/chills
  • Cough
  • Sore throat
  • Runny or stuffy nose
  • Muscle or body aches
  • Headaches
  • Fatigue (tiredness)


The flu can be severe in some populations, including the very young, very old and the immunocompromised.


Treatment for the flu can include various anti-viral medications and rest with an increased intake of fluids. Medications to help mitigate symptoms may be used as well.


Prevention measures include an annual vaccine which includes 3-4 strains of the most prominent influenza viruses of the season. In addition, practicing proper hand hygiene and cough etiquette can help to slow the spread among geriatric communities.



Common Viruses in Geriatric Communities: Viral Respiratory Pathogens


One of the most common viruses to sweep through long-term care facilities are viral respiratory pathogens. These viruses can cause anything from a mild cold to severe pneumonia.


SARS-CoV-2 is the virus that causes COVID-19. It is a coronavirus that attacks the lungs and other organs of the body and causes severe immune dysfunction in elderly individuals.


Symptoms of COVID-19 include:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea


These symptoms may appear 2-14 days after initial exposure to the virus. It is important to note that some people will be asymptomatic throughout their infection but may remain infectious.


Older adults and people who have severe underlying medical conditions like heart or lung disease or diabetes seem to be at higher risk for developing more serious complications from COVID-19 illness. Symptoms are slightly controlled with antipyretics, some inhaled steroids, and anti-inflammatories.


At the time this training was published, the FDA had approved the antiviral drug, Remdesivir, to treat certain cases of SARS-CoV-2. In addition, there were promising vaccine candidates in the works, with a couple receiving emergency-use authorization from the FDA.


**Note: Treatment options are rapidly changing. Please consult the CDC website to find the most up-to-date treatment options. 




Common Viruses in Geriatric Communities: Norovirus

Norovirus gastroenteritis is a virus that causes a severe stomach bug. It is easily transmissible through direct contact with infected individuals and has the potential for outbreaks in close quarters, like long-term care facilities.


The most common symptoms are:

  • Diarrhea
  • Vomiting
  • Nausea
  • Stomach pain


Symptoms generally appear between 12-48 hours after exposure and may last for up to three days.


There is no specific treatment for a Norovirus infection. If the infection is severe enough, fluids may be replaced via IV.   To prevent yourself from becoming infected with Norovirus, be sure to wash your hands with soap and water each time you interact with an infected individual.





Fungus and fungal spores are everywhere. They can be found in the soil, on an old shower curtain, and live in and on the human body, usually unnoticed. Most fungi are harmless like mushrooms, molds used in cheese making and yeasts used to make alcohol.


However, some fungi can cause illness. Many of these infections can easily be treated with antifungal medications. Sometimes, a resident may present with a fungal infection after a course of antibiotics for an unrelated infection. The antibiotics may have killed off beneficial bacteria opening the door for an opportunistic fungal infection.


Examples of fungal infections include:

  • Ringworm
  • Allergies to environmental molds
  • Candida is a fungus that can cause many different issues. While there are many different types of Candida, Candida albicans is the most common. Some Candida infections include:
    • Jock Itch (when colonizing areas of the male genitalia)
    • Vaginal yeast infections (when colonizing areas of the female genitalia)
    • Thrush (when colonizing the mouth and throat)
    • Diaper Rash
    • Athletes foot

Some fungal infections are especially harmful to populations with weakened immune systems. These are important to recognize due to the aging population inside long-term care facilities. These fungal infections include:

  • Pneumocystis jirovecii   pneumonia (PCP)
  • Invasive Candidiasis (when Candida colonizes the heart, blood, and/or brain)
  • Candida auris
    • This is an emerging, multi-drug resistant, fungal infection moving through long-term care facilities.


Parasites: Ectoparasites

Ectoparasites are multi-celled organisms that require a living host to survive. These organisms will bite on or burrow in the skin of its host. Occasionally these parasites act as vectors and can spread diseases, as in the case of a flea harboring bacteria that causes the Bubonic Plague or ticks transmitting Lyme Disease. More often, long-term care settings will see ectoparasites in the form on infestations.


These can include:

  • Scabies
  • Lice
  • Fleas



Common Parasites in Geriatric Communities: Scabies

Scabies infestations are caused by the colonization of mites that burrow into the top layer of skin and lay eggs. The infected individual will notice itching and a skin rash. The symptoms are caused by sensitization to the proteins and feces of the parasite.


The rash will have a small, pimple-like appearance on the:

  • Wrist
  • Elbow
  • Armpit
  • Penis
  • Waist
  • Buttocks
  • Shoulder blades


Scabies infestations may not be apparent for up to two months after the initial infection. Once someone has had scabies, subsequent infections can be noticed in 1-4 days.


Treatment for a scabies infestation includes a Scabicide lotion or cream. These medications should be applied to all areas of the body from the neck down to the feet and toes. Due to the intense itching, it is possible for someone who has a scabies infestation to develop a secondary infection at the scratch sites. These secondary bacterial infections should be treated as necessary.



Objectives Review

So far in Module 1, we have:

  • Discussed different pathogen types; and
  • Identified the most common communicable disease types seen in a long-term care setting.

The following slide will include a short concept check to help you demonstrate your understanding of the content provided.


If you wish to review the material please use the navigation arrows or page numbers located at the top of the page.





You have successfully completed Module 1: Introduction to Pathogens


Please review your score.

Save or print your certificate for your records.

Remember, there is no way to create a lost certificate of completion without retaking the course. If you do not keep a copy for your records, you will need to repeat this course.


Next up:

Module 2: Chain of Infection and Transmission