Ch. 12 - Soilborne and Arthropodborne Bacterial Diseases Flashcards Preview

Microbiology > Ch. 12 - Soilborne and Arthropodborne Bacterial Diseases > Flashcards

Flashcards in Ch. 12 - Soilborne and Arthropodborne Bacterial Diseases Deck (14):
1

Anthrax

soilborne bacterial disease

causative agent: bacillus anthracis (Gram pos)

endemic zoonotic disease - large herbivores ingest spores while grazing

bacillus anthracis produces a capsule and 3 exotoxins - thick capsule impedes phagocytosis

endospores germinate rapidly on contact with human tissue - produce vegetative cells

Treatment: penicillin, ciproflaxin

Bioterrorism: esp inhalation anthrax and cutaneous anthrax
-in mail 2001

2

Inhalation Anthrax

also, woolsorter's disease -- contaminated dust (sheer sheep, tan hides, etc)

highly lethal (w/o early treatment)

form of pneumonia: chills, cough, fever, SOB

3

Intestinal Anthrax

from contaminated and undercooked meat

acute inflammation of intestinal tract

nausea, vomiting, ab pain

4

Cutaneous Anthrax

skin abrasions from contact with spore-contaminated animal products (eg shaving bristles)

develop into black necrotic sore = eschar

5

Tetanus

soilborne bacterial disease

causative agent: Clostridium tetani (Gram pos, endospores)

spores enter body through deep puncture wound; germinate (in dead O2 free tissue of wound) into vegetative bacilli; produce several toxins

produce neurotoxin (tetanospasmin) - blocks inhibition of muscle contraction (NT GABA) -- constant spontaneous impluses to motor neurons -- muscle spasms and stiffness

formerly lockjaw (jaw muscle stiffness)

Treatment: penicillin and antitoxins

Immunization: TDaP, booster every 10 years after childhood vaccines (DTaP)

6

Gas Gangrene

soilborne bacterial disease

causative agent: Costridium perfringens (anaerobic, Gram pos)

produce group of toxins and hydrolytic enzymes

endospores in contaminated dirt -- introduced through severe open wound -- spores germinate in wound -- ferment muscle carbs and decompose musc protein

dead tissue (myonecrosis) blocks blood flow -- gangrene and gas below the skin (from muscle tissue being fermented) --> blue/black tissue necrosis

Treatment: Debridgement, hyperbaric oxygen chamber

7

Arthropod

invertebrate having joint limbs and a segmented body with an exoskeleton made of chitin

arthropod borne infections transmitted by insects (mosquitoes, sand flies) and arachnids (ticks, mites)

act as vectors - living organism that transmits disease agents --> acquire disease from taking blood meal from another animal

characterized by high fever and body rash

8

Plague

arthropod borne bacterial disease

causative agent: Yersinia pestis (facultative, gram negative)

killed about 40 million in Europe during middle ages

3 pandemics: 542 CE, Black Death (1300s), late 1800s

Treatment: antibiotics (stretomycin, doxycycline)

usual staining property = bipolar staining - stains heavily at poles of cell; safety pin appearance

9

Sylvatic Plague

carried in rodents/prairie dogs - spread by their fleas

SW USA

10

Urban Plague

from rodents to humans by flea bites

11

Bubonic Plague

1/3 forms of plague

cells accumulate in bloodstream, localize in lymph nodes = buboes

painful swellings

resist phagocytosis -- multiply in phagocytes
main virulence factor - F1 capsule

12

Septicemic Plague

1/3 forms of plague

= black death

spreads through bloodstream (hematogenous spread)

purple/black splotches from hemorrhages

symptoms: high fever, diarrhea, pain -- lead to meningitis

13

Pneumonic Plauge

1/3 forms of plague

spread via respiratory droplets -- when septicemic infections progress to lungs

highly contagious, extremely fatal
suffer cardiovascular collapse w/i 2-3 days

14

Lyme Disease

arthropod borne bacterial disease

causative agent: Borrelia burgdorferi (gram negative spirochete)

transmission: tick bite

ticks - live/mate in fur of deer

blood meal 24-36 hrs -- suck blood, defecate into wound -- spirochetes transmitted --> tick must remain attached for 24 hours

variable incubation period (3-31 days)

Stage 1: bull's-eye rash; fever, aches, flu-like symptons; will not itch!

Stage 2: spread to skin, heart, nervous system, and joints = joint/muscle pain

Stage 3: chronic arthritis and swelling in the joints

Treatment: amoxicillin, doxycylcine in early stages