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