Understanding Infection

NUR 154Spring 2010

The Chain of Infection

Key Terms

• Pathogen (agent)• Communicable• Pathogenicity• Virulence• Normal Flora• Colonization• Carrier

• Reservoirs• Toxins• Exotoxins• Endotoxins• Susceptibility• Host• Incubation

Period

• Primary Infection• Secondary Infection• Focal Infection• Endemic• Panendemic• Epidemic

Key Terms

Pathogens• Organisms that can cause illness/disease

– Bacteria, viruses– Fungi; intracellular organisms– Multicellular animals

• Cause disease in two ways– Divide rapidly to overcome body defenses– Disrupt normal cell function

• Secrete toxins– Disrupt normal cell function

Infectious Process

• Prodromal syndrome - preclinical or nondescript, nonspecific manifestations of a beginning infection.

• As the infection progresses, symptoms become more specific or severe.

Factors That Influence Susceptibility

• Natural Immunity• Age• Normal Flora• Environmental• Hormonal Factors

• Phagocytosis• Nutrition• Skin/MM Integrity• Medical

Interventions

Portals of Entry Sites

• Respiratory tract

• Gastrointestinal tract

• Genitourinary tract

• Skin/mucous membranes

• Bloodstream

Mode of Transmission

• Contact transmission by direct, indirect contact or fecal-oral transmission.

• Droplet transmission such as in influenza

• Airborne transmission such as in tuberculosis

• Vector-borne transmission involving insect or animal carriers, such as in Lyme disease

Physiologic Defenses Against Infection

• Body tissues

• Phagocytosis

• Inflammation

• Specific defenses– Antibody-mediated immune system– Cell-mediated immunity

Infection Control in Inpatient Health Care Agencies

• Nosocomial or health care–associated infections are infections acquired in the inpatient health care setting which were not present or incubating at admission.– Bacteremia NYS reportable event

• Endogenous infection is from a client’s flora.

• Exogenous infection is from outside the client, often from the hands of health care workers.

Nosocomial Infections• Infections that develop after the person

has been admitted to the hospital. Occur in about 2 million of the 30 million patients admitted to a hospital each year

• Common in very young, very old and persons w/chronic, debilitating diseases.

• Two contributing factors:– Concentration of virulent forms of different

organisms w/in hospitals.

– Presence of patients w/anatomic or physiologic defects in their immune defenses

Methods of Infection Control

• Practice hand hygiene and proper hand washing.

• No Artificial fingernails.

• Gloves should be worn.

• The CDC provides guidelines for disinfection and sterilization, outlining standard precautions for all modes of transmission.

What are the CDC hand hygiene guidelines?

Immunizations

Multiple Drug–Resistant Infections

• Multiple drug–resistant infections are no more transmissible than their drug-sensitive counterparts, S. aureus and Enterococcus organisms.

• To control antimicrobial resistance in health care settings, see the CDC program.

Problems from Inadequate Antimicrobial Therapy

• Noncompliance or nonadherence

• Legal sanctions that compel a client to complete treatment, such as in the instance of tuberculosis

• Septicemia

• Septic shock

Collaborative Management• History

• Physical assessment & clinical manifestations

• Psychosocial assessment

• Laboratory assessment including:– Culture and antibiotic sensitivity testing– Complete blood count– Erythrocyte sedimentation rate– Serologic testing– Radiographic and other assessment

Nursing Diagnosis

• Hyperthermia

• Risk for Social Isolation

Nursing Interventions

• Prevent the spread of infections. GOOD HANDWASHING

• Prevent complications.

• Treat symptoms of infection

• Monitor for secondary symptoms of infection

Hyperthermia Interventions

• Eliminate the underlying cause of hyperthermia and destroy the causative microorganism.

• Manage fever by:– Drug therapy: antimicrobial,

antipyretic therapy– External cooling, fluid administration

Health Teaching

• Education on these topics is vital to client’s understanding of transmission prevention precautions:

– Infection control– Drug therapy– Psychosocial support– Health care resources

Methods of Describing Bacteria

• Basic Shapes– Bacilli—rod shape– Cocci—spherical shape– Spirilla—spiral shape

Methods of Describing Bacteria

• Ability to use Oxygen– Aerobic—with O2

– Anaerobic—without O2

• Staining Characteristics– Gram positive– Gram negative

Anti-infective Drugs

• Known as antibacterial, antimicrobial, antibiotic

• Classified by – Chemical structures (e.g.,

aminoglycoside, fluoroquinolone)– Mechanism of action (e.g., cell-wall

inhibitor, folic-acid inhibitor)

Actions of Anti-infective Drugs

• Affect target organism’s structure, metabolism, or life cycle

• Goal is to eliminate pathogen– Bactericidal—kill bacteria– Bacteriostatic—slow growth of

bacteria

Mechanisms of Action of Antimicrobial Drugs

Widespread Use of Antibiotics

• Resistance not caused by but is worsened by over prescription of antibiotics– Results in loss of antibiotic

effectiveness

• Only prescribe when necessary

• Long-time use increases resistant strains

Widespread Use of Antibiotics (continued)

• Nosocomial infections often resistant

• Prophylactic use sometimes appropriate

• Nurse should instruct client to take full dose

Acquired Drug Resistance

What Can Nurses do to Prevent Infection in our

Patients?

Role of the Nurse

• Obtain specimens for culture and sensitivity prior to start of therapy

• Monitor for indications of response to therapy– Reduced fever– Normal white blood count– Improved appetite– Absence of symptoms such as cough

Role of the Nurse (continued)

• After parenteral administration, observe closely for possible allergic reactions

• Monitor for superinfections– Replace natural colon flora with

probiotic supplements or cultured dairy products

Drug Therapy in Infectious Disease

Penicillin

• Tx applications: pneumonia, meningitis, skin, bone, joint infections, stomach, blood & valve infections, gas gangrene, tetanus, anthrax, sickle-cell in infants.

• One of the safest class of drugs around for > 60 years

Cephlasporin• Tx applications: serious infections of

lower respiratory tract, CNS, Genitourinary, bone & joint.

• Avoid in patient with history of SEVERE penicillin reaction

• Primarily used for ampicillin-resistance hemophilus influenza and staphylococci which are penicillin resistant.

• Duricef, Kefzol, Keflex, Ceclor, Cefotan, Mefoxin, Rocephin, Lorabid

Tetracycline

• Tx applications: Lyme disease, cholera, typhus, rocky mountain spotted fever, Helicobacter pylori, chlamydial infections.

• Contraindicated in pregnant or lactating clients

– Effect on linear skeletal growth of fetus and child

• Contraindicated in children less than 8 yrs– Permanent mottling and discoloration of teeth

Macrolide Therapy

• Safe alternative to penicillin

• Tx applications: whooping cough, Legionnaires’ disease, H. influenza, Mycoplasma pneumoniae (infections caused by streptococcus)

• E-mycin, Erythromycin, Biaxin, Zithromax

• Almost no serious side effects, mild GI upset, diarrhea & abdominal pain most common.

• Drug to drug interaction with Coumadin

Aminoglycosides

• Reserved for serious systemic infections caused by aerobic gram-negative organisms

• Streptomycin is usually restricted to tx of TB

• Amikin, Gentamicin, Kantrex

• May cause nephro and ototoxicity even at normal doses.

Fluoroquinolones

• Tx applications: infections of Respiratory, GI, GU, Skin and Soft tissue.

• Postexposure prophylaxix for Anthrax

• Dosing advantage PO as effective as IV, dosing is 1-2 times a day

• Cipro, Floxin, Levaquin, Avelox

Sulfonamide Therapy• Tx applications: Pneumocystis carnii

pneumonia, shigella infections, UTI, RA, Ulcerative colitis

• Cetamide, Gantrisin, Bactrim, Septra

• Classified by their treatment applications systemic or topical

• Higher incidence of allergies due to sulfer content

• Interacts with anticoagulants

Antituberculosis Therapy• Contraindicated for clients with history of

alcohol abuse, AIDS, liver disease, or kidney disease

• Isoniazid (INH) Pyrazinamide(PZA) Ethambutol, rifampin, streptomycin

• Use caution for certain clients– Those with renal dysfunction– Those who are pregnant or lactating– Those with history of convulsive disorders

Other Drugs

• Clindamycin (Cleocin): for oral infections caused by bacteroides

• Metronidazole (Flagyl): used to treat H. pylori infections of stomach

• Vancomycin (Vancocin): effective for MRSA infections– Adverse effects: ototoxicity,

nephrotoxicity, red man syndrome

Selection of an Antibiotic• Careful selection of correct antibiotic

essential– Use of culture and sensitivity testing– For effective pharmacotherapy; to limit

adverse effects

• Broad-spectrum antibiotics – Effective for wide variety of bacteria

• Narrow-spectrum antibiotics– Effective for narrow group of bacteria

Multidrug Therapy• Affected by antagonism—combining

two drugs may decrease efficacy of each

• Use of multiple antibiotics increases risk of resistance.

• Multidrug therapy can be used– When multi-organisms cause infection– For treatment of tuberculosis– For treatment of HIV

Superinfections• Occur when too many host flora are

killed by an antibiotic

• Pathogenic microorganisms have chance to multiply– Opportunistic—take advantage of

suppressed immune system– Signs and symptoms include diarrhea,

bladder pain, painful urination, or abnormal vaginal discharge

Case StudyA 78-year-old nursing home patient with a

history hypertension, type 2 DM, & COPD, is brought into the ED with a history of fever for 72 hrs & moist cough. The LTC nurse report states that he was very irritable last night, then was difficult to awaken this am. Assessment findings include:

TPR: 103-122-26 (labored) BP: 100/56Lethargic-Confused, Crackles (rales) throughout

lung fields, CXR: Lung consolidation.IV fluids are running.

The following orders are written:Admit: medical unit

Sputum C&S Cefotetan 1gm IVPB Q12H

1. What are nursing responsibilities regarding these orders?

2. What type of antibiotic would you expect to be ordered and why?

Antibiotic S=Sensitive R=Resistant

AmikacinAmoxicillin

AzithromycinCefepimeCefotetan

LevofloxacinPipericillin

Tobramycin

RRSRRSRR

The Culture & Sensitivity report just came in and is as follows. What should the nurse do?

References• Adams, MP; Josephson, DL & Holland, LN (2008).

Pharmacology for Nurses a Pathophysiologic Approach (2nd ed). Upper Saddle River, NJ: Prentice Hall

• Center for Disease Control (CDC – 2007). Recommended Immunization Schedules for Persons Aged 0-18 Years. Retrieved on January 21, 2007 from http://www.cdc.gov/nip/acip

• Ignatavicius, DD & Workman, ML (2006) Medical Surgical Nursing critical Thinking for Collaborative Care 5th Ed. St Louis, MO: Elsevier/Saunders

• Hockenberry & Wilson (2007) Wong’s Nursing Care of Infants & Children 8th Ed. St. Louis, MO: Mosby-Elsevier