1) Association: The causative agent mut be present in every case 

2) Isolation: The causative agent must be isolated in every case of the disease and grown in pure culture

3) Causation: The cauastive agent is the pure culture must cause the disease when inoculated in a healthy and susceptible lab animal

4) Reisolation: The causative agent must be reisolated from the lab animal and be identicial to the original causative agent

-Bacterial Adhesin

-Capsules and other structures 

-Antigenic Variation  

-Enzyme Secretion 

Adhere to receptor molecules at a portal of entry in a velcro-like manner.

Example: Gonorrhea

Presence of a capsule material interfers with the process of phagocytosis, an important resistance mechanism in the host by which bacteria is engulfed by scavenger cells and elimanted. 

Contain M protein

Example: Plague, Anthrax

Unusual adaptation that allows them to grow in extreme environments.

Example: Helicobacter Pylori

-Exoenzymes

- Exotoxins

-Endotoxins

Secret enzymes

-also called spreading factors: help bacteria invade the surrounding tissue 

Part outer membrane of gram - (Ecoli 0157.:H7)

-causes shock chills, fever, small blood clots, possibly death

Virus

Defenses

Virus

Offense

Death (lysis) of host

Damage to plasma membrane

Inhibiting host metabolism

Common source (drinking water)

Propagated (person to person)

Is a site in nature in which  microbes source and multiply and from which they can be transmitted.

All pathogens must have a reservoir.

Humans: Only known reservoir for smallpox, gonorrhea, measles and polio.

Some organsims can survive and multiply in non-living env't (soil and water)

The mechanism by which an infectious agent is spread to a susceptible person

direct - contact, animal bite

indirect - airborne, vectors

Contact: Kissing, sneezing

Horizontal: Person to Person

example: AIDS, flu, STDs

Mother to child (trans-placental, breast milk, gonorrhea)

ex. AIDS, measles, chicken pox, syphilis, gonorrhea

arthropods, insects

mechanical: Passive

Biological vector: Necessary part of the life cycle ofa pathogen

Food Poisoning

-ingestion of bacterial toxins

- microbes may not be present

Staphylococcal aureus, a g+ coccus

-found in human nasal passages, part of normal flora

- heat stable enterotoxin

foodborne infection

caused by a series of salmonella bacilli

symptoms: nausea, vomiting, ect

Infects eggs in he ovaries of healthy hens

may contaminate meat, seafood, and fresh fruits and vegetables

some reptitles are carriers

crows: may have it in their feces

Thypoid fever

mainly in less-developed countries

fecal contamination

Transmission: by flies and fomites (inanimate objects)

-invades all lining of the small intestine, causing ulcers, bloody stools and delirium

(thypoid Mary, healthy carrier)

Shigella g- bacillus

symptoms: gastroenteritis possibly dysentery

severe diarrhea (Blood and mucus)

resulting dehydration can be deadly

Sources: eggs, shellfish, diary products, vegetables and

water

Treatment: Rehydration (oral or IV)

~1 million deaths/year in developing countries

transmission: fecal-oral, infectious dose (ID) is low

caused by exotoxin

secreted by vibrio cholera, a gram - coccus-rod

Source: consuming fecally contaminated food/water

Treatment: re-hydration must be instituted quickly to avert death

-epidemic in haiti

Gram - bacilli (non-pathogens, normal flora)

contaminates rare meats, fresh spinach

Most  common cause of travelers diarrhea

-e. coli is easy to culture/detect. presence is used to indicate fecal contamination

Campylobacteriosis

Caused by a g- bacillus

must frequent cause of bacteria diarrhea in US

1999 was contaminated in 70% of chicken

most are antibiotic resistant

Caused by g+ bacillus

contaminates cold cuts, hot dogs, and soft cheeses

grows under refrigerator

infants, toddlers, pregnant women susceptible

-pregnant women must get antibiotics immediately or risk miscarriage

g+ spore bacillus

trans: fecal-oral

associated with patients on antibiotics

depletion of normal flora by antibiotics allows it to "grow out"

Airborne bacterial disease

exotoxin produced by g+ bacillus

kills epitherial cells

may cause suffocation

toxin diffuses into bloodstream and my cause heart damage

Airborne Infection

caused by g- coccobacillus

humans only reservoir

trans by contaminated droplets

bind to epithelial cells in upper respiratory tract

exotoxin

reemerging disease every 3-5 years

large genus f g+ cocci, most virulent

transmission: respiration of droplets or contact w/ sores or open wounds

airborne infection

inflammation of the membrane covering spinal chord and brain

early diagnosis essential: cold-like symptoms progressing quickly to delirium and stiffness in neck and back

Neisseria meningitis - college student

G- bacillus

Primarily in kids under 5

~10% pop carriers

Gram - bacillus

Transmission: Inhalation of aerosols from contaminated water source

Most suspectible: middle aged and older, smokers & chronic lung disease

Prevention: Eliminating sources of warm, stagnant waters w/ potential for aerosolization

Mycobacterium tuberculosis

acid fast bacillus (waxy envelope)

~leading cause of death worldwide

10 million people infected 2 million deaths/year 8 million new cases/year

Problem: multiple drug resistance

g- bacillus

highly virulent: ID ~10

Reservoirs: small mammals

Potential bioweapon: Highly infectious and dissemination easy by aerosols

vaccine: only for high-risk groups

most common STD

obligate intracellular parasite

highest risk: young adults and teens

70% female, 30% males are asymptomatic

can cause infertility

Newborns required to have eye drops to prevent eye problems after birth

g- diplococcus

human resivor

2nd most common STD

asymptomatic - transmit gonorrhea for up to 10 years

if untreated causes pelvic inflammatory disease in 50% of Females

antibiotic resistance

eye drops for newborns by law

frequent co-infection with other STDs (AIDS)

humans only known reservoirs, no vaccine

most cases 20-39 year old bi/homosexual males 2/3 of cases

--can cause stillbirth and deformities

-produce urease

- cured w/ antibiotics

-associated with gastric cancer

-20% of pop under 40 and 50% over 60 infected 1/10 get ulcer

g+: normal flora of skin, mouth, nose and throat

normally harmless unless broken skin

-cause of pus--containing skin lesions

-can progress into systemic (bloodborne) infections

most virulent of staph

-MRSA leading cause of nosocomial infections in USA

impetigo: blister w/ highly infectious yellow discharge

- scaled skin syndrome

- Toxic shock syndrome

Soilborne disease

bacillus anthracsis G+ bacillus

primarily found in grazing animals

biowarefare/bioterrorism

antibiotics effective w/ early intervention

3 variations: inhalation (most severe), cutaneous, gastrointestinal

Spores of elastridium tetani

G+ bacillus

tetanospasm: 2nd most deadly bacterial toxin

germinal and multiply in deep anaerobic puncture wounds

prevents muscle relaxation

death by suffocation

Gram - bacillus

one of the most virulent bacteria known

1/3 of pop in Europe died

ID: 1 bacillus

Biological warfare: Japanese WII

Reemerging: increase global incidence

Zoonotic: rodents are primary reservoirs

G- intracellular bacteria

-emerging tickborne infection

2 forms: Human monoeytic ehrlichiosis

 Human anaplasmosis

-different different species cause them

g- spirochete

tickborne zoonosis: throughout us, esp NE upper midwest and pacific coast

-can cause symptosm of arthritis and numbness (years after infection)

diagnosis: history of tick exposure, symptoms, and + blood test for antibodies

- early treatment w/ antibiotics quick recovery

-no vaccine

obligate intracellular parasite

symptoms: rashes and flu-like

control: minimize contact with vectors and humans

in almost all 50 states

tick transfer

up to 20% die with no treatment

elderly esp. vulnerable

transmitted by fleas from mice and rats

Rickettsia prowazekii

transmitted by body louse

Gram - bacilli

most common: k. pneumonia and k. oxytoca

caused by; pnumonea, wound tissues, UTIs

Gram + cocci

normal flora of intestine

clinically important species:

E. faecolis and E. facium

disease caused by: UTIs, wounds, endocarditis

Gram + cocci

virulent strains have capsules--prevent phagocytes

commensial found in throat/nasopharynx

common cause of pneumonia

can cause sinusitis, meningitis, ear infections

gram - bacillus

name misnomer

infections: meningitis, pneumonia, sinus and ear infections

Group A:

scarlet fever, a-antigen

Group B:

neonatal disease

symptoms: pneumonia, meningitis and septics

infection in pregnant women

esp under children of 5

600,000 deaths/year mostly in Asia/Africa

ID: less than 10 particles

persist in env't

continue to shed after recovery

outbreaks w/ cruise ships, food service workers, hospitals

many different strains, immunity difficult

Inflammation of the liver (jaundice side affect)

usually mild, self-limiting w/ abrupt onset

fecal-oral transmission

usually not chronic

diagnosis: detection of antibodies in blood

may be eradicated soon, human only reservoir

2006: only Nigera, Pakistan, India and Afganistan have it

Transmission: person to person (fecal-oral)

indirect contact w/ infected saliva

Salk: killed 3 polio strains

Sabin: live, attenuated viruses

-most asymptomatic

-replication in nerve cells causes paralysis and deformities

A: causes no epidemics or pandemics, animals also reservoirs

B: doesn't cause epidemics, no animal resivors

C: causes epidemics, mild respiratory illness

H (hemagglutinin) 13 types attach to epithelial cells and gain entry

N (neuraminidase) 9 tpes, role in release of new viruses

117 possible combos