BMS 503 Microbiology Exam 4

the severity disease caused by an organism, LD50.

a balance between host and pathogen such that both are maintained.

Cholera toxin

Incidence Rate

Indirect Transmission

Zoonosis

False

Listeria monocytogenes is less pathogenic than Shigella dysenteriae.

Streptococcus mutans, fermentative metabolism

Produce

transformation, conjugation

diet, age, immune status

has the toxic activity; binds the cell and delivers the A-subunit to the cytoplasm.

False

Escherichia coli 0AT-M1LK is now lacZ+ and F-.

epidemic disease

False

Method of Delivery and Feeding

Bacteriophage transfer genetic information between bacterial cells through transduction, thus increasing the genetic diversity of bacterial populations.

Extracellular Polymeric Substance-- composed of protein, nucleic acids, and polysaccharide. It is where microorganisms are embedded in a biofilm

FALSE. much diversity in a biofilm

prevalence

mismatch, light, excision repair

PHOTOLYASE excises/cuts out THYMINE DIMERS, DnaPol I fills gap, DNA ligase links new and old dna

EXCISION REPAIR ENZYMES remove a SECTION of DAMANGED DNA, DNApol I fills gap, DNA ligase links new and old dna

MISTMATCH REPAIR ENZYME removes UN-METHYLATED BASE PAIR, DNApol I fills gap, DNA ligase links new and old dna

Large-scale DNA damage activates RecA, RecA cleaves LexA repressor protein. DNA POL V used to fix gap

1. Homologous
2. Site-specific

Needs RecA, requires two recombining molecules to have significant HOMOLOGOUS streches of DNA

Requires specific short sequence to be recognized by specific enzyme

Lysogenic phages, Transposons (mobile genetic elements that allow F plasmid to integrate in cell)

HOMOLOGOUS recombination

Def: DNA transfer NOT due to bacterial reproduction (unlike vertical transfer).

Types: Transformation, Conjugation, Transduction.

importing FREE dna into COMPETENT cells. (dna not always incorporated, often broken down)

gram positive

SOME gram negatives

no

Def: Bacteriophages carry host DNA from one cell to another

2 types: Generalized, specialized

1. can transfer any gene from donor -> recipient. 2. results in lytic pathway

can only transfer only a few closely linked genes. results in lysogeny

1. F+ to F-
2. only ONE strand transferred
3. requires contact

high freq. recombination: cells that have a plasmid incorporated

genetic element that can be integrated into host chromosome. example: F plasmid

filtration of phages (very small, also includes cells)

DNAse, make bacteria incompetent

filtration of cells

oriT and tra genes, oriR and replication maintenance genes, insertion elements, a transposon

entire chromosome is transferred

1. 1e14
2. 1e15
3. 1e14, intestine

HERVS: human endogenous retroviruses

Colonization can be transient or permanent, frequently begins at mucous membrane sites and need to move towards cell surface.

disease is when homeostasis is disrupted.

not all colonization causes disease

host provides benefit, bacteria has no effect on host

upper has biodiversity, lower is sterile

More anaerobes as you get further down towards colon. not many microorganisms in stomach + areas near it. Liver, gallbladder, pancreas are sterile

dental plaque.

Streptocuccus mutans grows in teeth biofilm, uses carbohydrates for fermentation, acids break down enamel

bacteroides dominated, prevotella dominated

Vagina slightly acidic-- lots of glycogen, lactobacillus acidphilus ferments it into lactic acid; bladder is sterile

Sebaceous/oily (forehead, back), moist sites (groin, foot, skin folds, etc), dry sites (forearms, buttocks, hands, etc)

non-normal in the flora, unlike opportunistic pathogens

Ability to cause disease, ID50 (infectious dose 50: number of organisms needed to colonize 50% of host population)

Disease sevity, Lethal Dose 50 (LD50): number of organisms to kill 50% population

pathogen metabolites that allow or organisms to cause disease

decrease or loss in virulence

reservoir, mode of transmission, immune response

Direct: person to person transmission
indirect: through intermediates such as fomites (inanimate objects) or reservoirs (organisms that carry)

phagocytosis, complement system (proteins bind to bacteria and promote lysis or phagocytosis), antibodies (bind to bacteria/products and neutralize, promote phagocytosis)

capsules: allow for attachment prevent antibodies, complement sys, and phagocytosis

toxins: obvious

pili: allow attachment, prevent phago. and compsys

Exotoxin: purpose is TO damage the host

endotoxins: have other purpose but illicit immune response " accidentally ". can over-illict IR and kill/shock host if conc too high

exo: cholera, tetanus, pertussis

endo: LPS and LTA

1. Cytolytic: pokes holes in host membrane
2. Superantigens: overactivate immune system, cause toxic shock syndrome
3. block protein synthesis (ie shiga toxin from dysentery )
4. proteases that cleave host cell proteins
5. blocking 2nd messenger pathways

both epi and outbreak are a higher amount of reported cases of disease than expected in an area. outbreak has smaller geographical region.

pandemic is very widespread, often worldwide

endemic: always present, can spike into an epidemic

Incidence: # new cases at a given peroid

incidence rate: # new cases of disease diveded by the number of people at risk

Prevalence: total of new + existing cases

P. Rate: measure of total disease in population, "____ out of 100,000 people"

mortality: death # in pop due to disease

morbidity: any departure from well-being (disability, death, illness)

no symptoms. the person is called carrier

transmission is direct

common: sharp rise and start. usually contaminated water or food
host-host: gradual rise and fall

any disease that effects primarily animals, but can infect humans

1. heat: reduce (pasteurization) or sterilize (canning) bacterial load
2. refrigeration: slows bacterial growth
3. dry/dehydration: removes water content

gastritis

General: Gastroenteritis

Small intestine: enteritis

Colon/large intetine AND small intestine: enterocolitis

Colon/large intestine: colitis

Intoxication: bacterial toxins ingested alongside food, symptom onset - 8 hours

Infection: microorganisms ingested w food, colonize GI tract. symptom onset - 12-24 hours

toxins that cause gastroenteritis

Infection, sometimes. NEVER for intocication.

listeria monocytogenes.

gram positive, coccobacillus.

fresh water or soil reservoir.

usually contaminates deli meats, found in other food groups as well.

point source spread, no human-human transmission

diagnosis via spinal fluid or blood sample

self-limiting, antibiotics in severe cases (penicillins, etc)

1 day incubation, 2 days of symptoms (nausea, headache, vomiting). Pregnant women especially, can cause miscarriages. self-limiting.

severe vomiting, diarrhea, cramps

resolves after 24 hours

gram positive cocci

Found on normal flora of nostrils and skin, contaminated surfaces. opportunistic infection or not

diagnosis through gram stain + MSA of food source

treatment via fluid replacement if necessary

gram-negative

reservoir: shellfish, water

2-3 days incubation times

airborne water droplets that are infectious

GOBLET CELLS produce a mucous to trap bacteria, CILIATED CELLS beat it upwards to prevent it from reaching lower. MUCOCILIARY CLEARANCE

sinus inflammation. viral infection, anti-virus fluid floods nasal pathways, but OOPS!! fluid good for bacteria. bacteria overgrow. infection

Ear cannal infection (bacterial), middle ear infection (same fluid thing as sinusitis). different seasonal incidence periods. both treated w antibiotic drops

inflammation of oropharynx-- bacterial or viral.

Symptoms worsening after 5-7 days or lasting over 10 days: likely bacterial

viral or bacterial. swelling + fluid filling of alveoli. 80% of cases is streptococcal pneumoniae.