Infection Control and Pathogens

Infection Control

• Infection happens when a pathogen starts a chain of events.
• Infection prevention involves breaking the chain of events.
• Nurses use infection control methods such as medical and surgical asepsis and standard precautions.

Types of Pathogens

• Pathogens can be microorganisms or microbes that cause infections.
• Pathogens are classified as bacteria, viruses, fungi, prions, and parasites.
• Bacteria examples include Staphylococcus aureus, Escherichia coli, and Mycobacterium tuberculosis.
• Viruses utilize a host's cells to replicate; examples HIV, hepatitis, herpes zoster, herpes simplex virus (HSV), and SARS-CoV-2 (COVID-19).
• Fungi include molds and yeasts like Candida albicans, and Aspergillus.
• Prions are protein particles which cause new variant Creutzfeldt-Jakob disease.
• Parasites include protozoa like malaria and toxoplasmosis, as well as helminths (worms) such as flatworms, roundworms, and flukes like Schistosoma.
• Virulence refers to a pathogen's ability to invade and harm a host.
• Herpes zoster is a common viral infection that appears years post-chickenpox exposure, affecting specific nerve tracts.

Immune Defenses

• Nonspecific innate immunity restricts entry of foreign organisms (antigens).
• Nonspecific immunity responds immediately through phagocytic cells, complement, and inflammation, irrespective of prior exposure.
• Passive immunity involves antibodies from an external source.
  • It provides temporary immunity without memory of previous exposures.
  • Intact skin acts as the body's first defense line.
  • Mucous membranes, secretions, enzymes, phagocytic cells, and protective proteins offer immune defense.
  • Inflammatory response that uses phagocytic cells, complement system, and interferons to confine and prevent spread of invasion.
• Specific adaptive immunity enables the body to produce antibodies in response to foreign organisms (antigens).
• Production of antibodies is directed at specific, identifiable microorganisms.
• Active immunity requires time to react to antigens.
  • It provides permanent immunity.
  • It involves B- and T-lymphocytes.
  • Specific antibodies (immunoglobulins IgA, IgD, IgE, IgG, IgM) are developed against specific antigens.

Infection Process

• Chain of Infection elements include causative agent, reservoir, portal of exit, mode of transmission, portal of entry, and susceptible host.
• Stages of infection include incubation, prodromal, illness, decline, and convalescence.
  • Incubation is the interval between pathogen entry and first signs.
  • Prodromal is the time from general findings to more distinct ones, while the pathogen multiplies.
  • Illness occurs when specific findings related to the infection manifest.
  • Decline is when manifestations subside as fewer pathogens are present.
  • Convalescence is when acute findings disappear and recovery takes days to months.

Risk Factors & Assessment

• A nurse should assess factors such as hygiene, health, and environment.
• Risks include inadequate hand hygiene and comprised immune systems.
• Compromised defenses include being immunocompromised, having surgery, indwelling devices, broken skin, poor oxygenation/circulation, or chronic/acute diseases.
• Providing care with medical or surgical asepsis that doesn't follow established standards.

Health-Care Associated Infections (HAIs)

• HAIs are infections a patient gets while receiving care in a healthcare setting.
• HAIs were previously called nosocomial infections, from either an exogenous or endogenous source.
• HAIs often occur in the ICU.
• The best method to prevent HAIs is through hand hygiene.
• Common HAI sites are the urinary tract from Escherichia coli, Staphylococcus aureus, and enterococci, plus surgical wounds, the respiratory tract, and blood.
• Iatrogenic infections are HAIs resulting from diagnostic or therapeutic procedures.
• HAIs are not always preventable or iatrogenic.
• Current evidence-based guidelines are recommended to prevent HAIs from multidrug-resistant organisms.
• Additional risks include poor hygiene/nutrition, smoking, excessive alcohol use, stress, crowded living, and advanced age.
• Older adults exhibit slowed antibiotic response and immunity, reduced subcutaneous tissue/skin thickness, decreased vascularity/wound healing, cough, gag reflexes, chronic illnesses, gastric acid production, mobility, incontinence, dementia, and device use.
• Risks from lifestyle choices include IV drug use/needle sharing and unprotected sex.
• Exposure risks include lack of sanitation, parasitic or mosquito-borne diseases, and diseases endemic to visited areas.

Expected Findings

• Systemic infection leads to fever, chills (during temperature rise), diaphoresis (during temperature decrease), high pulse and respiratory rate, malaise, fatigue, anorexia, nausea/vomiting, abdominal issues, and swollen lymph nodes.
• Older adults show atypical symptoms like agitation, confusion, or incontinence.
• Other symptoms include dyspnea, cough, sputum, lung crackles, dysuria, urinary frequency, hematuria, pyuria, rash, lesions, wound drainage, erythema, odynophagia, dysphagia, hyperemia, enlarged tonsils, altered consciousness, nuchal rigidity, photophobia, and headache.
• Inflammation has three stages; it's the body's local response to injury/infection.

The Inflammatory Response

• Stage one findings: redness due to dilated arterioles, local warmth, edema, pain/tenderness, and impaired use.
• Stage two involves killing microorganisms and exudate buildup; the exudate exits via the lymph system.
  • Exudate types: serous (clear), sanguineous (red blood cells), and purulent (leukocytes/bacteria).
• In stage three, scar tissue replaces the damaged tissue; new cells take on the old cells’ characteristics.

Laboratory Tests

• Laboratory tests look for leukocytosis, with WBCs greater than 10,000/μL.
• Increase the specific WBCs on differential (left shift if an increase in neutrophils)
• Monitor elevated erythrocyte sedimentation rate (ESR) over 20 mm/hr for inflammation or infection.
• Note the presence of microorganisms on culture.

Diagnostic Procedures

• Gallium scans (nuclear scans using radioactive material) are used to spot WBCs.
• Radioactive gallium citrate is injected IV and accumulates in inflamed areas.
• X-rays, CT scans, MRIs, and biopsies can determine infection, abscesses, and lesions.

Nursing Care

• Hand hygiene should be practiced consistently
• Educate about and encourage immunizations for target groups like children, older adults, the chronically ill, immunocompromised, and their contacts.
• Demonstrate and educate on oral hygiene to reduce protein and microorganism growth in the oral cavity.
• Encourage adequate fluid intake to prevent urine stasis, decreasing microorganism growth and maintaining skin integrity.
• Promote pulmonary hygiene for immobile patients (turning, coughing, deep breathing, incentive spirometry) every 2 hours.
• Employ aseptic techniques and PPE to minimize client exposure to microorganisms.
• Education on respiratory hygiene, covering mouth/nose when coughing/sneezing is important.
• Dispose of tissues, wear surgical masks, turn head away from others while coughing; and using hand hygiene after contact.

Isolation Guidelines

• Isolation uses hand hygiene and barrier precautions to reduce infectious organism transmission.
• Apply precautions to every client when contact with infectious materials is anticipated.
• Change PPE after contact with each client, or during procedures with the same client if blood/fluid exposure occurs.
• Clients in isolation risk depression/loneliness; provide support and sensory stimulation.

Precautions

• Standard precautions are for all body fluids (except sweat), non-intact skin, and mucous membranes.
• Alcohol-based hand sanitizers are needed before/after patient contact and glove removal.
• Alcohol-based waterless antiseptic is useful if hands aren't visibly soiled.
• Hand washing with soap and water is needed if contamination with spores is suspected.
• Nonantimicrobial or antimicrobial soap and water are needed if hands are visibly soiled.
• Use soap and water for and c. difficile.
• Gloves should be removed and hand hygiene completed between each client.
• When splashing may be possible, masks, eye protection, and face shields are needed.
• Clean gloves should be worn touching surfaces that may contaminate the nurse's hands.
• Hand hygiene is required after gown removal.
• Use moisture-resistant bags for soiled items and clean all client care equipment properly.

Transmission Precautions

• Bag and handle contaminated laundry carefully and use sharps safety devices.
• A private room is not needed if ability to maintain appropriate hygienic practices is present.
• Use airborne precautions for infections with droplets smaller than 5 mcg, like measles, varicella, SARS-CoV-2, pulmonary or laryngeal tuberculosis, including private rooms.

Airborne & Droplet Precautions

• Masks and respiratory protection devices for caregivers and visitors and N95/HEPA respirators are needed for tuberculosis or SARS-CoV-2.
• Negative pressure airflow in the room should have 6-12 exchanges/hr.
• Wear full face protection if splashing/spraying is possible.
• Clients with airborne infections need masks outside their room.
• Droplet precautions protect against droplets larger than 5 mcg traveling 3-6 ft, (streptococcal pharyngitis/pneumonia, Haemophilus influenzae type B, scarlet fever, rubella, pertussis, mumps, mycoplasma pneumonia, meningococcal pneumonia and sepsis, and pneumonic plague).
• Patients should have a private room or be with clients with the same infection, and have their own equipment.
• Masks for providers and visitors are key, and clients with droplet infections need to wear a mask outside the room.
• Contact precautions protect within 3 ft of the client (respiratory syncytial virus, shigella, enteric diseases, wound infections, herpes simplex, impetigo, scabies, multidrug-resistant organisms.

Infection Control Methods

• Contact precautions use private rooms or rooms with those with same infection.
• Gloves and gowns are worn by caregivers.
• Infectious dressings are placed in a single, nonporous bag without touching the bag's exterior.
• Protective environments are for immunocompromised clients, like those with allogeneic hematopoietic stem cell transplants.
• A protective environment needs a private room, positive airflow of 12+ air exchanges/hr, HEPA filtration for incoming air, and a mask for the client when outside the room.

Medications

• Antipyretics (acetaminophen and aspirin) reduce fever and discomfort with nursing actions like monitoring fever and documenting temperature fluctuations.
• Antimicrobial therapy kills/inhibits micro-organisms like bacteria, fungi, viruses, and protozoans.
• Anthelmintics should be given for worm infestations.

Multidrug-Resistant Infection

• Health care associated infections (HAIs) are infections acquired while receiving care in a health care setting from exogenous or endogenous sources.
• The best way to prevent HAIs is through proper hand hygiene.
• Common sites involve urinary tract (Escherichia coli, Staphylococcus aureus, enterococci), surgical wounds, respiratory tract, and bloodstream.
• Iatrogenic HAIs result from diagnostic or therapeutic procedures and HAIs are not always preventable.
• Use evidence-based practice guidelines to prevent HAIs due to multidrug-resistant organisms.
• Antimicrobials are becoming less effective due to pathogen resistance.
• Prevent new strains from evolving by limiting antibiotic use.
• Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to many antibiotics, but vancomycin and linezolid can be used to treat MRSA.
• Vancomycin-resistant Staphylococcus aureus (VRSA) is a strain resistant to vancomycin, but there are other antibiotics for the strain and specimens for culture and sensitivity are vital prior to antimicrobial therapy.

Additional Actions

• Antimicrobial levels should be monitored and maintained with client education on finishing antimicrobial course and avoiding overuse.
• Administer antimicrobial therapy as prescribed.
• Monitor medication effectiveness (reduced fever, increased comfort, decreased WBC count).
• Maintain medication schedule to ensure consistent antibiotic blood levels.
• Put surgical masks on clients with airborne or droplet infections, and cover draining wounds.
• Report communicable diseases to the CDC via their website, because there are over 60 diseases to be reported so that officials can treat diseases like tuberculosis.
• Outbreaks such as foodborne Hepatitis A should also be reported to plan/evaluate control and prevention through immunizations.

Client Education

• Key is identifying epidemic outbreaks to determine public health priorities based on trends.
• Education for patients at home involves measures, self-administration of medication, and complications to report.