Pathophysiology Chapter 4 Infection
Present in the cell wall of gram-negative bacteria and Released on death of bacterium
Endotoxins may cause fever and general weakness, or the may have serious effects on the circulatory system, causing increased capillary permeability, loss of vascular fluid and endotoxic shock
Prodromal period
Fatigue, loss of appetite, headache Nonspecific - "coming down with something" More evident in some infections that other
Effective against either gram-positive or gram-negative organisms
Narrow spectrum
Chlamydia, Rickettsiae, Mycoplasmas
Obligate intercellular parasites. Do not grow on artificial media. Some similarities with both bacteria and viruses. Lack some basic components. Classified as bacteria. Replicate by binary fission within host cell.
Local signs of inflammation
Pain, swelling, redness, warmth If bacterial - purulent exudate If viral - serous, clear exudates
Prions
Proteinlike agents that change the shape of proteins within host cells. Transmitted by contaminated tissues. Ingestion of meat, Infected blood or donor organs
usually harmless, but opportunistic Causative agent of thrush and vaginitis
andida
Sign of bacterial inflammation
purulent exudate
Disinfectants
used on surfaces or objects.
Antiseptics
used on the skin and tissues.
Major Groups of Bacteria
1. Bacilli: Rod-shaped organisms 2 Spirochetes: Include spiral forms and vibrio 3. Cocci or Spherical forms Diplococci Streptococci Staphylococci
Bacteria
1. Classified as prokaryotes 2. No nuclear membrane - no nucleus 3. Function metabolically and reproduce 4. Divide by binary fission 5 Complex cell wall structure 6. Do not require living tissues to survive 7. Vary in size and shape
Give a few examples of Microorganisms
1. bacteria 2. fungi 3. protozoa 4 viruses
Give 5 facts about microorganisms
1. they are small living forms 2 Include bacteria, fungi, protozoa, viruses 3. Many can grow in artificial culture medium 4. They are Non-pathogenic : Which meant that they Usually do not cause disease unless conditions change 5. Often beneficial
Infectious disease fully develops. Clinical manifestations reach peak. Length depends on virulence of organism.
Acute Infection
Factors that Decrease Host Resistance
Age (infants and elderly) Pregnancy Genetic susceptibility Immunodeficiency Malnutrition Chronic disease Severe physical or emotional stress Inflammation or trauma Impaired inflammatory responses
Drugs derived from organisms
Antibiotics
Antibacterial Antiviral Antifungal
Antimicrobials
Ingested with food that has been grown in feces-contaminated soil or prepared with hands that have been in feces-contaminated soil
Ascaris/Giant Round Worm
Bacteria in blood Small numbers for a short period of time Destroyed by circulating phagocytes but may lead to septiciemia
Bacteremia
Septicemia
Bacteria circulating and reproducing in bloodstream
Drugs that Drugs destroy organism
Bactericidal
Drugs that Decrease rate of reproduction or micro organisims
Bacteriostatic
Drugs may act by:
Blocking entry into host cell Inhibiting gene expression Inhibiting assembly of the virus
Effective against both gram-positive and gram-negative
Broad spectrum
These three groups of microorganisms have some similarities to both bacteria and viruses
Chlamydiae, Rickettsiae, and Mycoplasmas
Infection is not totally eradicated. Organism continues to reproduce in body. Clinical signs are present and usually milder than in acute infection. Periodic acute episodes may recur .
Chronic infection
Human prion diseases
Creutzfelt-Jacob disease and variant Creutzfelt-Jacob disease Both rapidly progressive and fatal
Using specific clinical specimens Drug sensitivity tests
Culture and staining techniques
What are plasmids
DNA fragments that are important in the exchange of genetic information with other bacteria
Some enzymes are also produced by some bacteria. What is the role of these enzymes that are produced by some bacteria?
Damage tissues and promote spread of infection
Virulence
Degree of pathogenicity
Modes of Transmission
Direct, Indirect, Droplet, Aerosol, Vector-borne
Continuous transmission within a population
Endemic
Higher than normal transmission or spread to new geographical area
Epidemic
What type of organism is Fungi?
Eukaryotic
some bacteria secrete toxic substances such as Toxins and enzymes. What are those toxins?
Exotoxins: Usually produced by gram-positive bacteria and diffuse through body fluids. Endotoxins: Present in the cell wall of gram-negative bacteria Released on death of bacterium Vasoactive compounds that can cause septic shock
Helminths
Flat or Round Worms. Are not microorganisms. They are Parasites. May be small or up to 1 meter in length. Life cycle with at least three stages: Ovum, larva, adult. Enter body through skin or by ingestion depending on species. Infections more commonly found in young children Infection can be life threatening in immune-suppressed client.
External capsule or slime layer
Found in some Outside the cell wall Offers additional protection
can cause neurological disease and can be transmitted to embryo/fetus if woman infected
Histoplasmosis
Examples of Fungal Diseases
Histoplasmosis. Tinea pedis (athlete's foot). Pneumocytosis carinii
Larvae enter skin from fecally contaminated soil in tropical areas
Hookworms
Antigen identification Antibody titer
Immunologic testing of body fluids
Aerosol transmission
Involve small particles from the respiratory tract Suspended in air and can travel farther than droplets
Basic structure of bacteria
It has an outer rigid cell wall which protects and provides a specific shape. Two types of cell walls that differ in chemical composition. Gram Positive and Gram Negative
Some species of bacteria can form spores. what are spores?
It is a coating that is highly resistant to heat and disinfectants. The bacteria can survive long periods in the spore state but they cannot reproduce when in the spore form. Dormant form of bacterium
Resident Flora
Many areas of the body have a resident population of mixed microorganisms termed normal flora. Skin Nasal cavity Mouth Gut Vagina Urethra
Mode of transmission
Method by which the agent reaches new susceptible host Air Water Direct contact Food
Super infections
Multi-drug resistant forms of existing diseases TB Staphylococcus aureus
Lack cell wall Cause of atypical type pneumonia
Mycoplasmas
Are all fungi pathogenic?
No, only a few are. Cause primary infection on skin or mucous membranes but may spread systemically particularly in immune-suppressed individual
Flagellae
One or more attached to cell wall. Provide motility for some species/bacteria. Assist in attachment to tissue and Transfer of DNA to another bacterium
Interference with bacterial cell wall synthesis
Penicillin
Assist in attachment to tissue and Transfer of DNA to another bacterium
Pili or fimbriae
ova inhaled in dust in fecally contaminated areas. Common in kids worldwide
Pinworms
Increase permeability of bacterial cell membrane
Polymyxin
Cause degenerative disease of the nervous system
Prions
Eukaryotic forms. Unicellular, lack cell wall.. Many live independently, others are obligate parasites. Pathogens are usually parasites.
Protozoa
Droplet transmission
Respiratory or salivary secretions are expelled from infected individual
Gram-negative. Transmitted by insect vectors (lice, ticks)
Rickettsiae
Control of Transmission and Infection
Standard precautions used in all settings with all clients when body fluids may be exchanged. Specific precautions in clients diagnosed with a particular infection. These are used in addition to standard precautions.
Most common form is transmitted by larvae in undercooked pork
Tapeworm
Interference with the synthesis of essential metabolites
Sulfonamides
Susceptible host
Susceptibility will depend on Health status Immunity Age Nutrition
Interference with protein synthesis
Tetracycline
Pathogenicity
The capacity of a microbe to cause disease
Incubation period
Time between entry of organism into the body and appearance of clinical signs of disease Vary considerable with different organisms
Pili or fimbriae
Tiny hairlike structures - found in some bacteria
Pandemic
Transmission has occurred on most continents
Example of protozoal diseases
Trichomoniasis (infection of reproductive tracts) Malaria Amebic dysentery
Active Viral Infection
Virus attaches to host cell. Viral genetic material enters the cell. Viral DNA or RNA takes control of cell. Uses host's cell to synthesize viral proteins and nucleic acids. New viruses are assembled in cytoplasm of cell. Viruses released by lysis of host cell or by budding from host cell membrane
Does fungi contain nucleus?
Yes it does
Leukocytosis
bacterial infection
purulent exudate
bacterial inflammation
They replicate by ______ but they lack some basic component, therefore they require the presence of living cells for reproduction
binary fission
How can you classify a virus?
by seeing the nucleic acid content, DNA or RNA and its form
A virus consists of a protein coat or capsid and a
core of either DNA or RNA. Protein coat comes in various shapes and sizes. Can change (mutate) quickly
Infection
organism is able to reproduce in or on body's tissues
sing of viral inflammation
serous, clear exudats
Fungal or mycotic infection occurs from
single-celled yeast or multicellular molds
Antimicrobial drugs should be taken until prescribed medication is completely used or until new drug is prescribed.
true
Some RNA-containing viruses contain reverse transcriptase enzyme to convert RNA to DNA.
true
Exotoxins:
usually produced by gram-positive bacteria and diffuse through body fluids.
viruses
very small obligate intracellular parasite that requires a living host cell for replication
Leukopenia
viral infection
serous, clear exudats
viral inflammation