Reservoir- A place where a pathogen can survive but may or may not multiply. *A variety of microorganisms live on the skin and within the body cavities, fluids, and discharges* BACTERIA: 1. Water-Most require water or moisture 2. Temperature- microorganisms can only live in certain temp ranges (IDEAL 20-43 degree C) -Bacteriostasis- cold temp prevent growth & reproduction of bacteria -Bactericidal- a temp or chemical that destroys bacteria 3. pH- Prefer pH from 5-7 4.
Light- Most microorganisms thrive best in dark environments such as under dressings and within body cavities Portal of exits- Blood, skin, and mucous membranes, respiratory tract, genitourinary tract, GI tract, and transplacental (mother to fetus). Susceptibility- degree of resistance to a pathogen Pathogenicity- extent of infection depends on the dose of the organism, and the susceptibility of the host. Inflammatory response-protective reaction that serves to neutralize pathogens and repair body cells *NON SPECIFIC Superinfection- when a broad-spectrum antibiotic eliminates a wide range of normal flora organisms, not just the infection.
Inflammation-body’s cellular response to injury, infection, or irritation. Inflammatory Exudates- fluid & cells that are discharged from cells or blood vessels -Serous- clear, like plasma -Sanguineous- contains RBCs -Purulent-WBC’s & bacteria COURSE OF INFECTION Incubation period- interval b/t entrance & appearance of 1st symptoms Prodromal stage- onset of non-specific S/S- onset of more specific symptoms Illness stage- interval when client manifests S/S specific to type of infection Convalescence- interval when acute symptoms or infection disappear Granulation tissue- scar tissue
HAIS (nosocomial infections)-health care associated infections *sites: urinary tract, surgical or traumatic wounds, Respiratory tract, bloodstream *HAIS are either exogenous ( present outside the body) or endogenous (part of normal flora or virulent organisms residing that could cause infection). Latrogenic infection- type of HAI from a diagnostic or therapeutic procedure. Client susceptibility- Many factors influence susceptibility; age, nutritional status, stress, disease process, medical therapy.
*Localized infections are most common areas of skin or mucous membrane breakdown, such as surgical or traumatic wounds, pressure ulcers, oral lesions, and abscesses. * To identify causative organisms, nurse collects specimens of body fluid such as sputum or drainage from infected body sites for cultures. * Rinse contaminated objects with COLD WATER to remove organic material. Hot water causes the protein in organic material to coagulate & stick to objects. Suppurative- pus forming infection
Asepsis- absence of pathogenic (disease-producing) microorganisms Medical asespsis- clean technique, lowers # of organisms present & prevents the transfer of organisms. Disenfection-process that eliminates many or all microorganisms with the exception of bacterial spores Sterilization-complete elimination or destruction of ALL microorganisms, including spores. ISOLATION PRECAUTIONS: Contact transmission: Direct- care & handling or contaminated body fluids (blood or body fluid from infected to workers direct skin.)
Indirect-transfer of an infectious agent through a contaminated intermediate object (contaminated instruments of hands). Droplet precautions: diseases that are transmitted by large droplets & expelled in the air 3-6 feet. Airborne Precautions: diseases transmitted by smaller droplets and remain in the air for a long period of time * requires a negative air flow room Protective environment: requires a positive airflow room (when airflow is set at >12 air exchanges per hour, and all air is filtered through a HEPA filter), very limited client population.
Epidemiology- cause and effect of health care associated infections. Sterile Field- An area free of microorganisms & prepared to receive sterile items. *Sterile touches sterile *Clean touches clean *Only sterile objects can be placed on sterile field *A sterile object out of vision is contaminated *A sterile object with prolonged exposure to air becomes contaminated *The edges ( 1-inch) around sterile field are contaminated Surgical scrub- scrub from fingers to elbows for 5 MINUTES Table 34-1 Common Pathogens and some Infections or Diseases they produce Bacteria Ecoli: found in the intestines.
Staph aureus: skin hair anterior nares mouth Strep a: nose mouth skin perianal oropharnyx Strep b: adult genitalia Tb: droplets from lungs and larynx Gonorrhea: mouth rectum and urinary tract Rickets: ticks Staph epiderm: skin Virus Hep a: feces Hep b and c: blood body fluids sexual contact Herpes type 1: lesions mouth saliva genitalia HIV: blood semen vag secretions via sexual contact Fungi Aspergillus: soil dust mouth skin colon genital tract Candida: mouth skin colon genital tract Protozoa Plasmodium: blood Table 34-2 Routes and Means Examples of Organisms Contact Direct.
Person-to-person (fecal, oral) Physical contact between source and susceptible host (e. g. , touching client feces and then touching your inner mouth or consuming contaminated food) Example of direct: Hepatitis A virus, Shigella, Staphylococcus Indirect Personal contact of susceptible host with contaminated inanimate object (e. g. , needles or sharp objects, dressings, environment) Example of indirect: Hepatitis B virus, hepatitis C virus, human immunodeficiency virus (HIV), Staphylococcus, respiratory syncytial virus (RSV), Pseudomonas, methicillin-resistant Staphylococcus aureus (MRSA).
Droplet Large particles that travel up to 3 feet and come in contact with susceptible host (e. g. , coughing, sneezing, or talking) Example of droplet: Influenza virus, rubella virus, bacterial meningitis Airborne Droplet nuclei, or residue or evaporated droplets suspended in air (e. g. , coughing, sneezing) or carried on dust particles Examples of airborne: Mycobacterium tuberculosis (tuberculosis), varicella zoster virus (chickenpox), Aspergillus, measles virus Vehicles Contaminated items Water Drugs, solutions Blood.
Food (improperly handled, stored, or cooked; fresh or thawed meats) Example of vehicles: Vibrio cholerae, MRSA, Pseudomonas, Legionella, Pseudomonas, Hepatitis B virus, hepatitis C virus, HIV, syphilis, Salmonella, Escherichia coli, Clostridium botulinum Vector External mechanical transfer (flies) Internal transmission such as parasitic conditions between vector and host, such as: Mosquito Louse Flea Tick Examples of Vectors: V. cholera Plasmodium falciparum (malaria), West Nile virus Rickettsia typhi Yersinia pestis (plague) Borrelia burgdorferi (Lyme disease).
TABLE 34-3 Normal Defense Mechanisms Against Infection Skin Defense mechanisms: Intact multilayered surface (body’s first line of defense against infection), Shedding of outer layer of skin cells, Sebum Action: Provides barrier to microorganisms and antibacterial activities, Removes organisms that adhere to skin’s outer layers, Contains fatty acid that kills some bacteria Factors that may alter defense mechanisms: Cuts, abrasions, puncture wounds, areas of maceration, Failure to bathe regularly, improper hand-washing technique, Excessive bathing Mouth Defense mechanisms: Intact multilayered mucosa, Saliva.
Action: Provides mechanical barrier to microorganisms, Washes away particles containing microorganisms, Contains microbial inhibitors (e. g. , lysozyme) Factors that may alter defense mechanisms: Lacerations, trauma, extracted teeth, Poor oral hygiene, dehydration Eye Defense mechansims: Tearing and blinking Actions: Provides mechanisms to reduce entry (blinking) or to assist in washing away (tearing) particles containing pathogens, thus reducing dose of organisms Factors that may alter defense mechanisms: Injury, exposure—splash/splatter of blood or other potentially infectious material into the eye.
Respiratory Tract Defense mechanisms: Cilia lining upper airway, coated by mucus, Macrophages Actions: Trap inhaled microbes and sweep them outward in mucus to be expectorated or swallowed, Engulf and destroy microorganisms that reach lung’s alveoli Factors that may alters defense mechanisms: Smoking, high concentration of oxygen and carbon dioxide, decreased humidity, cold air Smoking Urinary Tract.
Defense mechanisms: Flushing action of urine flow, Intact multilayered epithelium Actions: Washes away microorganisms on lining of bladder and urethra, Provides barrier to microorganisms Factors that may alter defense mechanisms: Obstruction to normal flow by urinary catheter placement, obstruction from growth or tumor, delayed micturition, Introduction of urinary catheter, continual movement of catheter in urethra Gastrointestinal Tract.
Defense mechanisms: Acidity of gastric secretions, Rapid peristalsis in small intestine Actions: Prevents retention of bacterial contents Factors that alter defense mechanisms: Delayed motility resulting from impaction of fecal contents in large bowel or mechanical obstruction by masses Vagina Defense mechanisms: At puberty, normal flora causing vaginal secretions to achieve low pH Actions: Inhibit growth of many microorganisms Factors that may alter defense mechanisms: Antibiotics and oral contraceptives disrupting normal flora.