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Bacterial diseases—> microbes that cause portals of entry—> exit related to the mechanism of transmission

Mechanism of transmission:

food/water borne

air

soil

arthropod-borne

STD’s

skin contact

Foodborne/water borne:

Food infection- ingest bacteria (24-72 hr)

Food intoxication- ingest toxins already made by bacteria(1-8 hr)

- replicated

ex. cholera, e.coli, salmonella typhi, b.cereus

Toxins: enterotoxin(GI tract), cytotoxin(cell) , neurotoxin- all exotoxin released during bacterial growth

some are g-, some g+

Ex:

Botuilism- intoxication of potent neurotoxin leads to paralysis, flasid paralysis so power 1 drop can kill RI

*potential bioterror weapon

clostridium, bacillus, have spores- must be cooked more than 10 min

2. Staphylorreus: can have enterotoxin and be invested with food very powerful, sometimes deadly

*diary products *unpasteurized juice- e.coli

3. Salmonossis: food infection undercooked egg/chicken. Also from touching reptiles

4 .Shigella dysenteriae- fecal-oral or waterborne infection of enterotoxin from humans

5. Vibrio cholerae/parahemolyticus- cholera; enterotoxin infection from water, food, raw shellfish; diarrhea so severe that loss of fluid can cause death without rehydration (oral or I-V) in ~ 5 hrs

6. Campylobacter jejuni- enterotoxin infection from poultry, water, & oral-anal sex

7. Listeria monocytogenes- enterotoxin infection from diary products, hot dogs, lunch meat; psychrotroph (in refrigerator) can cause miscarriage, or newborn death without antibiotics

8. E.coli 0157:H7- EID; enterotoxin from undercooked hamburg (Jack-in the-box deaths), radish sprouts, unpasteurized juice; can cause death from HUS

** most foodborne/waterborne diseases are Gm-, except Bacillus, Clostridium, +S. aureus

Conclusion- do not eat rare, over-easy eggs/food; wash hands!

B. Airborne/Aerosols- inhalation of droplets in air 2m sneeze or contaminated fomites

URI(upper respiratory): nose, pharynx-includes tonsils

Corynebacterium diphtheriae- deadly cytotoxin causing suffocation; prevented by DPT vaccine

Whooping cough- Bordetella pertussis- cytotoxin of the trachea and bronchi causes spasmodic coughing. Whooping cough surge and sometimes death; DPT vaccine protects up to ~12 years; new TDaP must be given at 13+; ~26 deaths/yr

Streptococcus pyogenes- strep throat—> scarlet fever, necrotizing fasciitis, toxic shock syndrome(from tampons); Streptococcus pneumoniae {can go in multiple places} (Jim Henson), glomerulonephritis, rheumatic fever; antibiotics early helps.

Meningitis- crosses blood-brain barrier: Neisseria meningitidis or Haemophilus influenza b {prevented by Hib vaccine}; young children and college students; (saliva exchange) vaccine available; can be deadly without antibiotics once rash appears

LRI(lower): bronchi, lungs

Streptococcus pneumoniae- 1.2 million deaths/year worldwide in children

Legionella pneumophila- emerged in 1976 in PA- almost 200 cases(elderly men), 29 deaths from AC ducts, spas, potting soil, vegetable mists; mostly prevented by bleach; also causes Pontiac fever (milder); erythromycin treats it.

Tularemia- Francisella tularensis- zoonotic from eating/touching rabbits, squirrels or inhalation(bioweapon); highly virulent.

TB- Mycobacterium tuberculosis- EID; leading cause of microbial deaths in world (2 million/year); MDRTB mostly due to AIDS

Mycoplasma pneumoniae is the only mycoplasma species known to cause disease of the human lower respiratory tract; no cell wall; so penicillin will not work —- aka walking pneumonia

C. STIs- direct contact- can be non-symptomatic; antibiotics

Syphilis- Treponema pallidum; 3 stages —> death, if not treated with antibiotics; can also transmit via saliva or vertically (mom to baby)

Chlamydia trachomatis- oral,anal, and vaginal sex; most common STD; mainly non-symptomatic; PID in females and blindness in newborns; (lymphogranuloma venereum) testicle swelling; painless genital ulcers. * Cause of- 28% of infertility

Trachoma- eyes- a highly contagious eye disease, which may result in blindness; spread by direct contact with eye, nose, and throat secretions contact with towels; may be carried by flies (direct contact, not STI)

3. Haemophilus ducreyi(chancroid)- painful genital ulcers/swelling

4. Gardnerella vaginalis- burning on urination and foul-smelling discharge in females; treat with metronidazole

5. Gonnorrhea- Neisseria gonorrheae- (“clap”) via oral, anal, vaginal sex allowing pili of bacteria to adhere to G-U tissue; PID in 50% females and blindness in newborns; antibiotics

D. Helicobacter pylori- cause stomach ulcers—> gastric cancer, if untreated with antibiotics; unknown transmission. Iatrogenic(by the physician) transmission of H.pylori following endoscopy is the only proven mode.

E. Skin contact

Leprosy- Hansen’s disease: Mycobacterium leprae; occasionally inhaled, mostly skin contact transmission; painful lesions; antibiotics

Staphylococcus aureus- boils, carbuncles, pimples, wound infections, impetigo, toxic shock syndrome (tampons). exotoxin, decreases blood pressure—> shock; nosocomial(hospital)

Clostridium perfringens- gas gangrene from deep wound

F. Soilborne (soil, manure, dust)

Anthrax- Bacillus anthracis- spore former; bioweapon; 3 forms- cutaneous, GI, inhalation (most deadly); antibiotics; vaccine exists

Tetanus- Clostridium tetani- spore former; neurotoxin causing locked muscles including jaw and diaphragm —> death; antibiotics; DPT vaccine; neonatal tetanus in poverty-stricken countries

Leptospira interrogans- spirochete in dog, cat, rat urine- contaminated water by soil; flu-like symptoms’ can be fatal

G. Arthropod-borne:

Plague- Yersinia pestis- Black Death; highly virulent; internal hemorrhaging, death; buboes (painful, swollen lymph nodes); pneumonic form is ~100% fatal(bioweapon); rat flea vector

Rickettsias(intracellular parasites) a. Rickettsia rickettsii- Rocky Mountain Spotted Fever- dog tick vector; serious, fatal without early antibiotics; b. Rickettsia typhus- rat flea vector- endemic form; c. Rickettsia prowazekii- human body lice vector- epidemic form

Human granulocytic/monocytic ehrlichiosis— Ehrlichia canis/Ehrlichia chaffeensis- tick vector; antibiotics; flu-like and other symptoms similar to Lyme

Lyme- Borrelia burgdorferi- deer tick vector; mostly in NE, also Europe; flu-like start, bulls-eye rash, arthritis—> dissemination, without antibiotics

Relapsing fever- Borrelia recurrentis- tick vector or, in epidemic form, body lice vector from other humans in poverty areas; antibiotics