Exam 4 Flashcards
Define Pathology.
Study of disease
Define Pathogen.
Disease causing agent
Define Etiology.
Cause of disease
Define Pathogenesis.
Manner in which the disease develops
Define Infection
Invasion of body by pathogens
Define Disease.
Infection causes a change in state of health (abnormal state)
When does normal microbiota initially develop?
Formed at birth
Where and how are normal microbiota initially introduced into the body?
As the baby leaves the birth canal, as the baby eats and breathes
Define Normal Microbiota.
Microbes that colonize the body without causing disease
Where does normal microbiota get nutrients?
Secretory products of cells, body fluids, dead cells, food in gastrointestinal tract
Name 3 physical and chemical factors that affect normal microbiota.
pH
temperature
oxygen
List 5 factors that alter the number and types of normal microbiota from one person to another.
a. age
b. Diet (nutrients)
c. Living conditions
d. occupation
e. Personal hygiene
Define Symbiosis.
Relationship between normal microbiota and host
Define Commensalism and give 1 example.
One organism benefits and the other is unaffectedEx. Corynebacterium inhabits the eye and lives on dead cells
Define Mutualism and give 1 example.
Both organisms benefit
Ex. E.coli in large intestine synthesize vitamin K
Define Parasitism and give 1 example.
One organism benefits and the other is harmed
Ex. any virus
Define Opportunistic pathogen and give 1 example.
Pathogen that can cause disease if conditions change
Ex. E.coli can become harmful if it is in bladder, lungs, spinal cord
List Koch’s Postulates
a. The same pathogen must be present in every case of the disease.
b. The pathogen must be isolated from the diseased host and grown in pure culture.
c. The pathogen from the pure culture must cause disease when it is inoculated into a healthy, susceptible laboratory animal.
d. The pathogen must be isolated from the inoculated animal and must be shown to be the original microbe.Classifying Infectious Diseases
Define Symptoms.
Changes in body function
2 Examples:
Pain and malaise
Define Signs.
Can be observed and measure
4 Examples:
Lesions, swelling, fever, paralysis
Define Communicable disease.
Disease that spreads quickly from one host directly or indirectly
5 Examples:
Chickenpox, measles, genital herpes, typhoid fever, tuberculosis
Define Contagious disease.
Easily spread from one person to another
2 Examples:
Chickenpox and measles
Define Noncommunicable disease.
Not spread from one person to another
1 Example:
Tetanus
Define Endemic disease.
Disease constantly present
1 Example:
Common cold
Define Epidemic disease.
Many people in a given area acquire a disease in a short period of time
1 Example:
influenza
Define Pandemic disease.
Epidemic that is worldwide
2 Examples:
Influenza, AIDS
Define Acute disease.
Develops rapidly but lasts a short period of time
1 Example:
influenza
Define Chronic disease
Develops slowly but is recurrent or lasts a long time
3 Examples:
Mononucleosis, tuberculosis, hepatitis B
Define Latent disease.
Microbe remains inactive but later becomes active to produce symptoms
1 Example:
Shingles—varicella zoster (virus)
Define Local Infection.
Invading microbes are limited to a small area
2 Examples:
Boils and abscesses
Define Systemic infection.
Microbes spread throughout the body
Example:
Measles
List 4 predisposing factors that would make the body more susceptible to
disease.
a. gender
b. Genetic background
c. Inadequate nutrients
d. age
Define reservoir of infection.
Source that provides a pathogen with adequate conditions for survival and multiplication
List 3 reservoirs of infection.
a. human
b. animal
b. nonliving soil and water
Define carriers.
Person that harbors pathogen (without showing signs of illness) and can transmit them to other
List 3 diseases that human carriers spread.
a. AIDS
b. gonorrhea
c. typhoid fever
List 2 diseases transmitted by animals.
a. rabies
b. lyme disease
List the two major nonliving reservoirs of infection.
a. soil
b. water
Name 2 microbes that from nonliving reservoirs that can cause infections.
a. Clostridium tetani
b. Clostridium botulinum
Define Contact Transmission.
Spread of agent of disease by direct, indirect, droplet
Give 3 examples of direct contact (person to person) transmission.
Touch, kissing, sexual intercourse
Give 3 examples of illnesses causes by direct contact transmission.
Common cold, hepatitis A, STD, measles
Define Indirect contact transmission.
Nonliving objects
Define Fomite.
Nonliving objects
3 Examples of fomites:
Needles,tissues, bedding
Give 3 examples of illnesses caused by fomites.
HIV (needles), tetanus, hepatitis B
Define Droplet transmission.
Mucus droplets travel less than one meter
3 Examples:
Cough, sneeze, laugh
Give 3 examples of diseases spread by droplet transmission.
Influeza, pneumonia, whooping cough
Define Vehicle of transmission.
Transmitted by food, water, air, blood, drugs, body fluids
Define Vectors.
Animals that carry pathogens
Define Nosocomial Infection.
Hospital-acquired infection
Nosocomial infections are the result of 3 factors:
a. Microbes in hospital environment
b. Compromised status of host
c. Chain of transmission in the hospital
According to the CDC, handwashing is the single most important
means of preventing the spread of infection.
CDC reports that on average, health care workers wash their hands before interacting with patients
40% of the time.
Define Epidemiology
Science that studies when and where disease occur and how they are transmitted
- List the 4 mechanisms of which bacteria become resistant to chemotherapeutic agents.
a. destruction or inactivation of drug
b. prevention of penetration of target site
c. alternation of drug target site
d. rapid ejection
List reasons why antibiotics are no longer effective (human causes).
Misuse, dose regimen too short, poverty, overprescribed
Ciproflaxin (nalidixic acid)
- inhibits DNA synthesis
- used to treat Anthrax, UTI’s, pneumonia
Linezolid (Zyvox)
- developed in 2001
- 1st new class of antibiotics in 25 years
- inhibit protein synthesis (50S subunit of ribosome)
- treats gram positive bacteria
- used to combat MRSA
Sulfoamides
- also called sulfa drugs
- inhibits the synthesis of metabolites
- first synthetic drugs created
- used to treat UTI
Erythromycin
- inhibits protein synthesis
- treats gram positive bacteria
- used to treat pneumonia, strepto and staphylo cocci infections
Rifampin
- inhibits nucleic acid synthesis
- used to treat tuberculosis and leprosy
Tetracycline
- produced by Streptomyces
- inhibits protein synthesis
- used to treat gram positive and negative bacteria and can penetrate body tissues
- used to treat urinary tract infections (UTI), pneumonia, and chlamydial infections
Bacitracin
- derived from Bacillus
- inhibits cell wall synthesis
- used to treat gram positives such as staphylococci and streptococci
- applied topically
Cephalosporin
- usually given orally
- inhibits cell wall synthesis
- used to treat gram negative bacteria
Semisynthetic penicillin
- chemically modified the mold Penicillium
- broad spectrum of activity
- inhibits cell wall synthesis
- used to treat gram negative and gram positive
- Examples: amoxicillin and ampicillin
Natural penicillin
extracted from the mold Penicillium
- narrow spectrum of activity
- inhibits cell wall synthesis
- used to treat staphylococci and streptococci
- shouldn’t be taken with acidic foods because they will decrease its effectiveness
- susceptible to penicillinases
Define antimicrobial drugs.
Class of chemotherapeutic agents used to treat infectious disease
Define broad-spectrum of activity.
Affect gram positive and gram negative bacteria
Define spectrum of activity.
Range microbes that antibiotics affect
Why is it difficult to treat viral infections?
The virus is in our cells and we don’t want to harm our cells
Why is it difficult to treat fungal or protozoan infections?
They are eukaryotic cells and so are humans
Name 3 ways eukaryotic and prokaryotic cells differ.
a. cell wall
b. ribosome
c. metabolic reactions
Which is easier to develop drugs against prokaryotic or eukaryotic cells and WHY?
Prokaryotic because we are eukaryotic and we don’t want to damage our cells
Which type of bacteria (2) produces most antibiotics, which molds produce most antibiotics?
Streptomyces and Bacillus
Penicillium and Cephalosporium
Spectrum of Antimicrobial Activity
Are all antibiotics that are discovered used in treating disease, explain?
No, toxic to humans
Where was the organism first isolated from a moldy cantaloupe bought?
Peoria, IL
Define antibiotic.
Substance produced by microbes that inhibit growth of another microbe
What bacterium was first noticed to be inhibited by Penicillium notatum?
Staphylococcus aureus
What is Penicillium notatum?
Mold
Who discovered Penicillium notatum?
Alexander Fleming
Who coined the term “chemotherapy”?
Paul Ehrlich
How do antimicrobial drugs kill microbes?
Interfere with growth
Penicillin
- 50 chemically related antibiotics
- different based on the chemical side chains
- produced naturally or semisynthetically
- inhibit cell wall synthesis
what is pathogenicity?
ability to cause disease
depends on ability to invade, multiply, and evade host defenses
what is virulence?
degree of pathogenicity
pathogen?
disease causing agent
host?
where pathogen lives
infeciton
growth of the microbes on a host
why do micbrobes want in?
animals provide favorable environment
- rich in organic food
- maintain Temp and pH
what are portals of entry?
where pathogens enter
ex. mucous membrane
types of mucous membrane for POE?
resp. tract
gastrointestinal tract
urogential tract
what is things to know about resp. tract POE?
enter by inhalation
most common POE
Ex. common cold, pneumonia, strep throat, TB, influenza, measles, and chicken pox
what are things to know about the gastro intestial tract POE?
enter by food or water, contaminated objects
Ex. Hepititis A, typhoid fever, and food poisoning
what are thing to know about the urogential tract POE?
transmitted sexually
Ex. HIV, Genital warts, herpes, and gonorrhea
what is the skin POE?
prime target for pathogen cant be penetrated unless its injured
what is the parental route POE?
when microbes enter injured skin or mucous membrane
Ex. injection, bites,cuts, surgery, and burns
what is the perfered POE?
pathogens has to enter body in a certain way in order to cause disease
Ex.Clostridium tetni must enter though punctured skin to cause tetanus
what is the number of invading microbes?
more microbes present the greater the chance disses happens
LD50
ID50
what is LD50
lethal dose ( dose required to kill 50% of test animals)
whaat is ID50
infectious dose (dose required to produce infection in 50% of test animals)
what is adhesion?
once pathogens are inside host they attach to tissue
how is adhesion accomplished?
ligands or adhesion(fimbrae) which bind to receptors on the host’s cell
if adhesion or receptors are altered
then infection can be prevented
What are examples of adherence
S. mutans (cause cavities) attaches to surface of teeth by glycocalyx
what are the pentration of Host defense- capsules
glycocaylx around cell wall prevent phagocytosis
Ex. Streptococcus pneumonia and Bacillus anthraets
what are the cell wall componets of penetration of host defense?
m protien
mycolic acid
what are M proteins
heat and acidic resistance protein prevents phagocytosis
Ex. Streptococcus pyogens (strep throat)
what is mycolic acid
waxy lipid in cell wall prevents phagocytosis
Ex. myobacterium tuberculosis (TB)
what are the enzymes in part of pentration of host defenses?
leukocidin collagenase coagulase hyalurondinase hemolysin
what is leukocidin?
destorys leukocytes
what is collagenase
destroys collagen
what is coagulase?
coagulates fibrinogens
Ex. staphylococcus aureus (staph infection)
what is hyaluronidase?
digest hyaluronic acid (host cell together)
Ex. streptococcus pyogenes (Flesh Eating)
what is hemolysin
the lyse RBC
what are the types of hemolysin?
alpha, beta, and gama
what is alpha hemolysin?
partial breakdown of hemoglobin adn produces green color around colonies
Ex. S.Mitis and S. salivarius (normal microbiota)
what is beta hemolysin?
complete breakdown of hemoglobin and produce clear zone around colonies
Ex. S.pyogenes (strep throat and scarlet fever)
what are gama hemolysin?
no breakdown of hemoglobin
Ex. S. epidermis (normal microbiota)
what are the four ways damage to cell wall can occur?
- use host nutrients
- direct damage (lyse host cell)
- toxin (poisouns substance)
- induce hypersensitivity
what is toxigenicity?
ability to produce toxin
what is toxemia?
presence of toxin in blood
what is some toxin info?
can be transported by blood or lymph
can inhibit protein synthesis, destroy blood cells, damage blood vessels, and disrupt NS function
40&% of all toxin cause damgae to cell membrane of hos
what symptoms do toxin cause?
fever. shock, diarrhea, and cardiovascular problem
what ate the two types of toxins?
Endotoxin and Exterotoxins
whar are exotoxins
toxins relase directly inot the blood system
made of proteins
mainly gram positive
produce specific disease symptoms
what are the types of extotoxin?
neurotoixin
enterotoxin
cytotoxin
what is neurotoxin
attack nerve cells
Ex. E. clostridium tetani (uncontrolled muscle contrations0
what is enterotoxin?
affects gastrointestinal tract
Ex. E. Stapholococcus aureus ( food poisoning)
what is cytotoxin?
lyse host cell
Ex. E. closridium perfringens (gas gangrene)
what are endotoxin?
toxin produced as part of cell wall and released when cell is damaged
gram negative
in LPS layer
antibiotic can worsen it
what do all endotoxin produce as symptoms?
chills, fever, weakness, aches, possible shock
but in varying degrees
