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MICRO TEST #3

Terms in this set (85)

Etiology
the study of the cause of a disease
pathogenesis
the development of a dsease
Virulence
The degree of pathogenicity of a microbe. (how good of a pathogen)
Infection
Colonization of a body by pathogens
Erogenous disease
a disease caused by the normal flora (microbiota)
Normla flora (microbiota)
permanent residents, relatively fixed types of microorganisms regularly found in a given area of the body
Normla flora (microbiota) #2
common from human to human, but everyone has their own unique "micro biome". Will reestablish themselves after antibiotics
Transient microbiota
inhabit the skin or mucus membranes for hours- months, will not necessarily reestablish themselves after antibiotics
Transient microbiota #2
sometimes potential pathogens which re carried w/o causing disease, not considered part of the normal microbiota (flora)
Symbiosis
the relationship between normal microbiota and the host
commensalism
one organism benefits, and the other is unaffected
mutualism
both organisms benefit
parasitism
one organism benefits at the expense of the other
Opportunistic pathogens
an infectious microorganism that is normally a commensal or does not harm its host but can cause disease
Where do you find Normal Microbiota on the human body
Nose and throat, eyes, mouth, skin, large intestine and Urinary and reproductive systems
Why is the skin unfavorable environment for most microorganisms?
Dry, washed organism off, skin sheds and your skin is salty
Demodex folliculorum
follicle mites, live and breed in eyelashes and hair follicles of most adult humans
Common diseases in the pharynx ( throat)
staphylococcus, diphtheroids, streptococcus
Common nose pathogens
staphylococci and diphtheroids
Lower Respiratory Tract
are sterile; any transient organisms are trapped by mucus
What happens if you lose your teeth as far as colonizing?
reverts to alpha hemolytic streptococci
What happens if you get dentures as far as colonizing?
anaerobes return.
Is there normal flora in the blood?
Normally sterile, transients from the moth may be found following dental work or even vigorous brushing of teeth.
Flora in GI
sterile at birth, first week after birth 99% bifidobacterium
What is a common normal skin microbiota (flora)
Staphylococcus
Where in the human body is not colonized with normal microbiota?
bloodstream
Bacillus anthracis has an ID50 when entering through the skin, and ID50 of 10,000 to 20,000 when inhaled, and an ID50 of 250,000-1,000,000 when ingested. Which portal of entry is the most successful (least host resistance) for Bacillus anthracis?
Skin
Enterotoxins affect cells in the
gastrointestinal tract
Which of the following virulence factors enable(s) bacteria to avoid phagocytosis by white blood cells?

capsule

coagulase

O polysaccharide

all of these
All of these
A microbe-host association in which the microbe benefits but the host is unaffected
Commensal
Babies acquire most of their normal flora in utero? T/F
False
Coagulase destroys blood clots? T/F
False
Which of the following statements about exotoxins is FALSE?

They are more potent than endotoxins.

They are composed of proteins.

They are usually destroyed by heat.

They have specific methods of action.

They are located in the cell wall of gram-negative bacteria.
They are located in the cell wall of gram-negative bacteria.
Which of the following is NOT a mechanism of antibiotic drug resistance among bacteria:

efflux pumps which remove the antibiotic

enzymes which inactivate/destroy the antibiotic

alteration of the antibiotic target site

blocking antibiotic binding site or penetration

inhibiting cell wall synthesis
inhibiting cell wall synthesis
Beta-lactamase works by
inactivating/destroying penicillin
Portal of Entry for bacteria
Mucous membranes, skin, parenteral route
ID50
infectious dose for 50% of the test popluation
LD50
Lethal dose (of a toxin) for 50% of the test population
Adhesions or ligands
Bind specifically to complementary surface receptors on cells of certain host tissues
coagulase
coagulates fibrinogen
kinase (fibrinolysis)
digest fibrin clots
Hyaluronidase
Hydrolyzes hyaluronic acid, helps organism invade epithelium.
Collagenase
hydrolyzes collagen
Neuraminidase
degrades neuraminic acid
IgA proteases
destroy IgA antibodies
Protection from Phagocytosis
Capsule, S layer, M protein and O antigen
Toxin
substance that contributes to pathogenicity
Toxemia
presence of toxin in the host's blood
Toxoid
inactivated toxin used in a vaccine
Antitoxin
antibodies agains a specific toxin
Superantigens (exotoxins)
Cause an intense immune response due to release of cytokines from host cells. Symptoms include fever, N/V/D, shock and death
Which arthropod is the vector of Lyme disease?
Tick
Some one sitting next to you on the bus sneezes on you. This is an example of what type of transmission?
Droplet
An example of a fomite would be?

a contaminated bedpan

a drinking glass used by a patient

bandages from an infected wound

a cutting board

all of these
All of these
Which produce exotoxin A, which is responsible for the rapid tissue destruction of necrotizing fasciitis?
Beta-hemolytic Gr A Streptococci ( S. progenies)
Which is correct regarding Salmonella gastroenteritis?

transmitted by fecal-oral route

causative agent has many serotypes

associated with poultry and chicken eggs

symptoms include diarrhea

all of the above
All the above
Transmission of Disease:

two types of direct
Direct contact and Droplet spread
Transmission of Disease:

3 types of indirect
Airborne, Vehicleborne and Vectorborne
Direct contact
Requires close association between infected and susceptible host
Droplet contact
Transmission via airborne droplets; within 1 meter of host
Indirect:

Airborne
carried by dust of droplets suspended in the air
Indirect:

Vehicleborne
food, water, body fluids and fomites (inanimate objects)
Indirect:

Vectoborne
insect carrier
Nosocomial infections
• Are acquired as a result of a hospital stay, Affect 5-15% of all hospital patients
Staphylococcus epidermidis
Gram-positive bacterium. It is part of the normal human flora, typically the skin flora, and less commonly the mucosal flora
Staphylococcus aureus
Gram-positive, round-shaped bacterium that is a member of the Firmicutes, and it is a member of the normal flora of the body, frequently found in the nose, respiratory tract, and on the skin.
Urinary System Infections:

Cystitis
an inflammation of the urinary bladder
Urinary System Infections:

Urethritis
an inflammation of the urethra
Urinary System Infections:

pyelonephritis
an inflammation o fone or both kidneys
leading cause of UTI?
E. coli
listeriosis
most cases are asymptomatic or flulike symptoms. possible birth issues, sepsis and meningitis >25% mortality rate
Streptococcus mutans
normal flora of mouth, bacteria colonize teeth. ferments sucrose to lactic acid which erodes enamel.
Streptococcus pneumoniae
pneumonia, otitis media, gram-positive diplococci, capsule.
streptococcus pneumoniae
causes pneumococcal meningitis, leading cause of meningitis since Hib vaccine. most common in children 1m-4y. Mortality 30% child, 80% elderly
Bordetella pertussis
Whooping cough, capsule. prevented by DTaP.
Whooping cough stages
1. catarrhal stage, like common cold
2. paroxysmal stage, violent coughing sieges
3.Convalescence stage
Impetigo
crusting sores, spread by autoinoculation, most common in age 2-5y
Toxic Shock syndrome
wound infections by staph. that produce the TSS toxin
Staphylococcal food poisoning
intoxication, produced by some Staph when they grow in food. ingestion of toxin cause sever GI upset, vomiting, diarrhea.
Hemolysins
lyse RBC's (Streptolysin O)
Streptokinase
break down blood clots, used as clot buster drugs to treat heart attack patients
M proteins
help organism adhere to mucous membranes, prevents microbe from being phagocytizd killed by WBC's.
Infection
growth of a pathogen, incubation is from 12hr-2weeks, fever
intoxication
ingestion of toxin, symptoms appear 1 to 48 hours after ingestion
Gastroenteritis
diarrhea, dysentery (bloody diarrhea)
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