Infectious Diseases

Chain of Transmission: Pathogenic agent

Any organism that can cause disease

Chain of Transmission: Resevoir

Is an environment where an organism can live/multiply

Chain of Transmission: Portal of exit from the reservoir

Organism leaves the reservoir

Chain of Transmission: Mode (mechanism) of transmission

Direct (physical contact)

Indirect: through a “fomite”like a telephone, tray table, countertop

Chain of Transmission: Portal of entry into the host

Invasion

Chain of Transmission: Susceptible host

Lots of reasons that may increase/decrease the chances of infection

Signs and symptoms of infectious diseases

Systemic: fever, chills, sweating, malaise, nausea, and vomiting

Abscess, rash, red streaks, and inflamed lymph nodes

Red streaks

As bacteria travels to the lymph nodes or blood stream, leads to rapid systemic deterioration

Pathogenicity

Capacity of microbes to cause disease

Invasiveness

Concept of pathogenicity that refers to the ability to spread

Toxicity

Concept of pathogenicity that refers to the ability enzyme, endotoxin, exotoxin production. Damage cells or interfere with host functions

Adherence to/compatibility with tissue

Concept of pathogenicity that refers to how compatible the microbe is to the tissue

Pili (different tools that bacteria are going to use to adhere to tissue)

Streptococci in respiratory system

Avoidance of host defenses

Concept of pathogenicity that refers to mutations and “shields”

Local Infection symptoms

Organism enters the body and is confined to a specific location.

Ex: Abscess → leukocytes form wall around infection to prevent spreading

Systemic infection symptoms

Spreads to several sites and tissues

Ex: fever, chills, sweating, malaise, nausea, and vomiting

Standard Precautions

Type of microogranisms (bloodborne pathogens/all clients)

• Hand hygiene

• PPE

• Clean patient care area/equipment with disinfectant

• Handle laundry carefully

  • Ensure proper handling of sharp objects

Airborne Precautions

Transmission through small particles that suspend in air and dispersed by air current

• Private room

• Door closed

• Patient isolation

• PPE when enter room with. a fit-tested respirator

Droplet Precautions

Transmission through sneezing, coughing, talking within 3 feet of patient

• Private room or housed with others with same infection

• Door can remain open

  • PPE to include mask

Contact Precautions

Transmissions through direct contact with patient

• Private room

• PPE (gloves /gown) on entry and all interactions

• Limit transporting patient

• Disinfect equpipment

Hand Hygiene: When to wash with soap and water

Visibly soiled with blood/bodily fluid

After eating

After using restroom

Exposure to patients with clostridiodes difficile (c-diff)

Hand Hygiene: When to use alcohol-based rub

Before and after having contact with a patient

Before and after putting on gloves for patient care

After contact with objects in the patient room

Bacteria

Unicellular organisms that do NOT require living tissue to survive their own metabolic processes

Target for drugs as human cells do not have cell walls but this organism does

Viruses

Require a living host for replication

Hard to treat because they hide inside human cells

Lack own metabolic processes that drugs may interfere with and replicate/mutate frequently

Protozoa

Unicellular, with nucleus and more cell structure than bacteria

Parasites (ex. malaria)

Fungi

Unicellular, promoted by warmth and moisture

Reproduce by budding or spores

Some are pathogenic

• Athlete’s Foot → invasion of superficial layers of skin

• Histoplasma → causes lung infection

How does infectious disease differ in aging adults compared to younger adults?

Older adults are MORE susceptible to infectious diseases

• Changes in cell-mediated or T-cell function → slower to respond and require a stronger stimulus

• Changes in skin elasticity/strength

• Cough and gag reflexes make it more difficult to control secretions

• Decreased bronchiolar elasticity and mucociliary activity

• Possible increased exposure when living in assisted living communities

Clostridiodies difficile (c-diff)

Anaerobic, spore-forming bacillus caused by antibiotic medication

Can live for weeks or months without a host in water, soil, animal and human feces

Most common causes of healthcare-associated diarrhea

With antibiotic treatment, good bacteria is killed, but this bacteria is RESISTANT

Can be influenced by chemotherapy, GI surgery, enteral feeding

Sign/ symptoms/ Clinical manifestations of c-diff

Mild diarrhea to severe colonic inflammation leading to death

Persistent diarrhea/loss stools (3 or more times a day for 24 hours)

Abdominal cramping and tenderness

Severe infections may include fever and sepsis

Preventative measures for c-diff

Proper handwashing: 1-2 minutes of soap and water followed by proper hand drying

Gloves, gowns

Chlorine-based or high-concentration hydrogen peroxide to clean surfaces

Use of disposable equipment

Responsible use of antibiotics

Staphylococcal Infections

Bacterial infection that is among most common microorganisms that colonize on skin and mucous membranes

Most common infection site is in the nostrils

Spreads by direct contact with surfaces, or people, or inhalation of infected droplets

Stimulate a strong host immune response

• Neutrophils are recruited to a local infection to attempt to contain the infection

• Can spread to bloodstream (systemic)

Signs/Symptoms/Clinical Manifestations of Staphylococcal infections

Can range from mild skin infections to life-threatening systemic disease (sepsis)

Preventative measures for Staphylococcal infections

Washing hands

Gloves/gown

Mask (if infection site is the nostrils)

MRSA

Antibiotic resistant staph infection that requires extremely strong drugs (vancomycin)

Streptococcal Infections: Group A (GAS)

Airborne, contact transmission

Present in nasal cavity and pharynx

Rheumatic fever

• Carditis

• Arthritis

• Nodules

• Chorea-choreiform movements

• Erythema marginatum (non-itchy rash)

Progresses rapidly

Causes severe tissue damage as it spreads and destroys the soft tissue in its path (necrotizing fasciitis and strep gangrene)

Streptococcal Infection: Group B (GBS)

Infections in pregnant women and neonates

Leading cause of neonatal pneumonia, meningitis, and sepsis

Streptococcal cellulitis

Acute spreading inflammation of the deep dermis and subcutaneous tissues

Usually results from infection of burns, wounds, or other breaks in the skin

Painful, warm, and swollen with accompanying erythema

May have systemic symptoms such as fever and chills

Streptococcus pneumoniae

Bacterial infection that colonizes in the upper respiratory tract

• Invasive (meningitis)

  • Intracranial pressure/brain edema, headache, nausea, altered metnal status, stiff neck, fever

• Noninvasive (pneumonia)

  • Fever, chills, pleuritis/chest pain, fatigue, productive cough

Preventative measures for Streptococcus pneumoniae

Droplet:

• Private room or housed with other with same infection

• Door can remain open

• PPE to include mask

Direct contact;

• Private room

• PPE (gloves/gown) on entry and for all interactions

• Limit transporting patient

• Disinfect equipment

Dry Gangrene

Line of demarcation

Poor blood supply causing necrosis

Wet Gangrene

Moist, progressive

Bacterial infections

Gas Gangrene

Edema, gas pockets, foul odor

Caused by anaerobic bacteria

Preventative measures for Gas Gangrene

Look for signs of ischemia:

• Cool skin

• Pallor or cyanosis

• Sudden severe pain/edema

• Loss of pulse in involved limb

Psychological support

Pseudomonas

Opportunitistic pathogen, one of the most aggressive

Early diagnosis and detection is important

Clinical manifestations of Pseudomonas

Skin or wound infections

• green-pigmented discharged at the infected site

Urinary tract infections

Pneumonia

Can cause sepsis

Herpes Simplex-1

Transmitted by direct contact

Oral herpes (cold sores or “fever blisters”)

Herpes Simplex-2

STD, Genital herpes

Transmitted by direct sexual contact

Herpes Type 3

Varicella Zoster Virus

Causes chicken pox and shingles

Clinical manifestations of Herpes Type 3

Chicken pox

• Rash (“dew drop on a rose petal”) presentation

Shingles

• Blisters erupts unilaterally on a specific dermatome supplied by dorsal root ganglia

Herpes Type 4

Epstein Barr

Spread by saliva → “kissing disease”

Causes infectious mononucleosis

Fever, sore throat, headache, malaise, abdominal pain (enlarged spleen of liver)

Excellent prognosis, but symptoms persist for 1-3 months

Pyrogens

Substances that result in
activation of the hypothalamus to
increase heat production

104

Temperatures ______ and above degrees Fahrenheit may causes delirium and seizures (irreversible cell damage)