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195 Cards in this Set
- Front
- Back
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What is a reservoir?
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Place where a pathogen spends most of its time.
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What is direct contact?
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Contact from host to host.
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What is a vector?
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Living organism that carries the disease, but is not affected by it.
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What is a vehicle/fomite?
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A nonliving object that carries the pathogen.
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What is sporadic occurrence?
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The disease is present sometimes, not present others. (seasonal)
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What is endemic occurrence?
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Constantly present, but in low numbers.
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What is epidemic occurrence?
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high percentage has the disease.
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Types of epidemic?
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common source - everybody gets it at once from a common source
propagated - person to person (wider spread) pandemic - lots of people get it |
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Types of control?
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Against reservoir
Herd immunity Against Transmission |
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What is virulence?
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Level of disease caused by a pathogen
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Clinical stages of disease
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Infection
Incubation Prodromal Invasive/acme Dead or Decline Convalescence |
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What is the infection stage?
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Pathogen initially infects host.
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Incubation stage?
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Pathogen becomes established. Depends on:
Pathogen Host Size of innoculum Distance between infection site and part of body effected. |
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Prodromal Stage
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Initial onset of symptoms
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Invasive/acme stage
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Disease is at its worst.
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Types of infectious diseases?
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Acute (quick, intense)
Subacute Chronic (long-lasting, less severe) Latent (S/S are not always present) |
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Types of infections?
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Local (restricted to one area)
Focal (pathogen is localized, effect is spread) Systemic (spread throughout system or systems) |
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Types of septicemia?
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Bacteremia
Viremia Sapremia (parasites in the blood) Fungimia |
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Enzymes involved with infection
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Hyaluronidase
Collagenase Streptokinase Coagulase Hemolysin |
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What does hyaluronidase do?
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Breaks down the substance that holds cells together.
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What does collagenase do?
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Breaks down connective tissue.
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What does streptokinase do?
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Breaks down blood clots.
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What does coagulase do?
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Causes plasma to coagulate.
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What does hemolysin do?
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Lyses blood cells.
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Discuss exotoxins.
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Excreted by living gram+ organisms.
Most dangerous toxin produced by cells. Most dangerous: botulinum. |
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What are enterotoxins?
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Exotoxins that effect intestines' ability to absorb water.
Staph. aureus Bacullus serus |
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Discuss endotoxins.
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Produced as part of the cell wall of a gram- cell.
Affects host when cell dies. Shigella, Salmonella |
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What is the causal organism of Lyme Disease?
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Borrelia burgdorferi.
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Pathogenicity of Lyme Disease.
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Produces an outer surface antigen as a type of camouflage against white blood cells.
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Stage 1 of Lyme Disease
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flu-like symptoms
50% get bullseye rash |
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Stage 2 of Lyme Disease
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Weeks to months later - complications in heart/nervous system
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Stage 3 of Lyme Disease
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Can cause repeated attacks of arthritis
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Treatment of Lyme Disease
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Single dose of Doxyclycine can be given to adults.
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What is the causal organism of Syphilis?
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Treponema pallidum
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What type of bacteria is Treponema pallidum?
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Gram negative spirochete.
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What are the stages of syphilis?
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Incubation, Primary, Secondary, Tertiary.
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What are the symptoms in the first stage of Syphilis?
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Chancres - hard, painless, nondischarging lesions that disappear after 4-6 weeks.
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What are the symptoms in the secondary stage of syphilis?
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disappear and reappear in 5 yr. period
-copper-colored rashes -whitish mucous patches with high populations of bacteria. |
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What happens in the tertiary stage of syphilis?
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permanent damage in various body systems.
neurosyphilis: ataxia, thickening meninges, paralysis, insanity. Gummas: granulomatous inflammations (internal or external) |
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What is the treatment for Syphilis?
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Penicillin
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What are the signs of congenital syphilis?
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notched incisors, saddle-nose, perforated palate, saber shins
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What is the causal organism of ulcers?
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Helicobacter pylori
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What type of bacteria are Helicobacter pylori?
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Gram- microaerophilic spirochete
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What are the symptoms of peptic ulcers?
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Stomach pain, indigestion, possibly vomiting, bleeding, high correlation with stomach cancer.
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What are the treatments for ulcers?
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Tagamet controls ulcers
Tetracycline or penicillin can be given. Omeprazole reduces stomach acid. Pepto relieves pain. |
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What causes travler's diarrhea?
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Campylobacter species
(most commonly C. jejuni) |
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What kind of bacteria are campylobacter?
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microaerophilic, helical, Gram-
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How is Campylobacter transmitted?
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Injesting infected food or water.
Contact with infected animals. |
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What are the hosts of Campylobacter?
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humans and animals
(birds have optimum temperature and don't get sick) |
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What are possible antibiotics to treat travler's diarrhea?
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Erythromycin and Floroquinolone
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What is the causal organism of UTI and burn infections?
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Pseudomonas aeruginosa
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Describe Pseudomonas aeruginosa
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Aerobic gram- rod
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How are UTIs and burn infections treated?
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antibiotics such as amoxicillin, trimethoprim, quinolones, or sulfonamides
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What is the causal organism of Legionaires Disease?
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Legionella pneumophela
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How was L. pneumophela spread at the veterans' convention in 1976?
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through the air vents.
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Describe Legionella pneumophela
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Aerobic gram- bacillus
Does not ferment sugars |
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How is Legionaire's disease spread?
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It is airborne.
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What complications of Legionaire's disease lead to death?
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Shock and kidney failure
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What are the symptoms of Legionaire's disease?
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Fever, chills, headache, diarrhea, vomiting, fluid in lungs, pain in chest and abdomen
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What is the treatment for Legionaire's disease?
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Azithromycin, a fluoroquinolone, or erythromycin
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What is the causal organism of gonorrhea?
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Neisseria gonorrhoeae
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What is the shape of Niesseria gonorrhoeae?
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Diplococci
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What is PPNG?
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Penicillinase producing Niesseria gonorrhoeae
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What do Fimbriae of Niesseria gonorrohoeae do?
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allow it to attach to epithelial cells of urinary and reproductive tract
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How is gonorrhea transmitted?
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Direct: sex, birth canal
Indirect: dirty hospital sheets |
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Possible symptoms of Gonorrhea
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pharyngeal: asymptomatic or sore throat
anorectal: asymptomatic or constipation, pus, rectal bleeding, Infection in cervix/urethra |
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What is stage 1 of Gonorrhea?
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Pus, sometimes yellow discharge from penis or vagina.
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What is stage 2 of gonorrhea?
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bacteremia
Fever, joint pain, endocarditis, skin lesions, arthritis or “frozen pelvis” |
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How is gonorrhea diagnosed?
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molecular probe, not culturing.
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What is the recommended treatment for Gonorrhea?
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cephalosporin ceftriazone, ciprofloxacin, ofloxacin or levofloxacin plus azithromycin or doxyclycine (also treats Chlamydia)
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What is the causal organism of Meningicollal Meningitis?
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Neisseria meningitidis
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What is the causal organism of Streptococcus Meningitis?
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Streptococcus pneumoniae
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What is the causal organism of Haemophilis Meningitis?
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Haemophilus influenza
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What is the causal organism of Listeriosis?
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Listeria monoctyogenes
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Describe Niesseria meningitidis
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Gram- Diplococci
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How is meningitis transmitted?
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A.Carriers or endogenous bacteria
B.Bacteria gain access directly to meninges, such as from surgeries or trauma C.Bacteria spread to meninges from blood from another infection D.Meninges are protected by arachnoid layer; meningitis can result if the defenses are overwhelmed E. Can be transmitted through direct contact with respiratory fluids. |
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progression of meningitis
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B.In meningococcal meningitis, bacteria colonizes in the nasopharynx, spreads to the blood, then grows rapidly in the meninges.
C.Symptoms may develop as quickly as a few hours, or up to a few days. D.Symptoms develop quickly because meningococci produce 100 to 1,000 times as many endotoxins as other types of bacteria. |
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What are the symptoms of meningitis?
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A.Early symptoms: headache, fever, and chills
B.Necrosis C.Clogging of blood vessels, causing hemorrhaging D.Decreased cebrospinal fluid flow E.Edema, causing increased pressure inside the skull F.Central nervous system impairment G.Less often, seizures |
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Prevention of meningitis
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A.Vaccines for Types A and C, but not B
1.Meningococcal polysaccharide vaccine 2.Meningococcal conjugate vaccine |
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How is meningitis treated?
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Penicillin
Third-generation cephalosporins and ampicillin |
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What is the causal organism of Bubonic plague?
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Yersinia pestis
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Describe Yersinia pestis
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Gram- bacillus, facultative anaerobe
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How is bubonic plague transmitted?
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Indirect
Reservoirs: rats, mice, squirrels, prairie dogs Vectors: fleas that carry rodent's blood |
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Progression of bubonic plague
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skin ->lymphatic system-> lymph nodes
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Symptoms of bubonic plague
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high fever, black lesion on skin surrounded by cracking skin, swollen lymph nodes, digital gangrene, constantly vomiting blood.
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Treatment of bubonic plague.
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aminoglycosides, Protein synthesis inhibitors (streptomycin, doxycycline, tetracycline)
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What is the causal organism of cholera?
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Vibrio cholerae
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How is Vibrio cholerae classified?
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Facultative anaerobic gram- rod
Can survive outside the body in a cool environment |
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How is cholera transmitted?
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Contaminated water or food.
Usually contaminated with feces. |
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Progression of Cholera
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Invades intestinal mucosa and releases enterotoxin.
Bacteria binds to small intestine and inhibits sodium absorption. Intestinal lining becomes shredded. White flecks in feces. |
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What are the symptoms of cholera?
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Nausea, vomiting, severe, watery diarrhea, muscle cramps, dehydration, shock
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Treatment of cholera
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oral rehydration solution
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Prevention of cholera
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stay away from contaminated food/water.
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Describe Staphylococcus aureus
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Gram+ Salt-tolerant facultative anaerobe.
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What does S. aureus produce?
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Enterotoxins - can survive extreme temperatures
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What are the symptoms of Staph. food poisoning?
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N/V, Diarrhea, abdominal pain, no fever
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What is the causal organism of appendicitis?
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Bacteriodes fragilis
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Describe Bacteriodes fragilis.
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Normal inhabitant of intestines.
Anaerobic Gram- Rod |
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What are the symptoms of appendicitis?
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abdominal pain, loss of appetite, nausea, vomiting, constipation or diarrhea, inability to pass gas, low fever, abdominal swelling, rebound tenderness
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Complications of appendicitis
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Peritonitis
Abcesses |
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What causes Rocky Mountain Spotted Fever?
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Rickettsia rickettsii
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Describe Rickettsia Rickettsii.
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Gram- , aerobic, obligate intracellular bacteria.
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How is RMSF transmitted?
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ticks are reservoirs/vectors. Esp. American dog tick and Rocky Mountain wood tick.
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How does Rickettsia Rickettsii progress?
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-spreads through bloodstream and infects endothelial cells
-invades host cell by attaching to cell membrane and entering through phagocytosis -reproduces by binary fission creates holes in blood vessel walls |
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What are the S/S of RMSF?
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3-4 days: fever, nausea, vomiting, headache, muscle pain, lack of appetite
later: rash, abdominal pain, joint pain, diarrhea rash appears on ankles and wrists as faint pink macules. |
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What is the treatment of RMSF?
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Tetracycline within 4-5 days.
Doxycycline is best. Chloramphenicol for pregnant women. |
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What are the forms of Typhus fever?
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Epidemic, Endemic, Scrub disease
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What is the causal organism of Typhus fever?
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Rickettsia prowazekii
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Describe Rickettsia prowazekii
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Gram- aerobic rod
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How is Rickettsia prowazekii spread?
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Vector: louse
Reservoir: humans |
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What is the incubation period of typhus fever?
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about 12 days
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How does a person become infected with typhus fever?
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Bacteria reproduce in digestive tract of louse, louse defacates while biting host, bite wound gets contaminated.
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What are the symptoms of Tyhpus?
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Fever, headache, weakness, muscle aches, chills, stupor. Rash after 6-7 days
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What are possible treatments for Typhus?
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Antibiotics such as tetracycline, doxycycline, or chloramphenicol.
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What is the most common bacteria STD in the United States?
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Chlamydia
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What is the causal organism of Chlamydia?
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Chlamydia trachomatis
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Describe Chlamydia trachomatis
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Obligate intracellular, spherical
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How is Chlamydia transmitted?
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Direct contact of bodily fluids (sex)
Passed to eye by contaminated hand congenital |
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How does Chlamydia trachomatis enter cells?
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Small elementary bodies enter host cell by phagocytosis.
6-8 hrs: lose thick walls and enlarge to become reticulate bodies. Reproduce, then condense to become infectious elementary bodies. elementary bodies released by lysis of cell. |
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What is the incubation of Chlamydia trachomatis?
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1-3 weeks
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What are the symptoms of Chlamydia in women?
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abnormal vaginal discharge, burning when urinating,
worse: lower abdominal pain, low back pain, nausea, fever, pain during intercourse, bleeding between periods |
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What are the symptoms of Chlamydia in men?
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Discharge from penis, burning sensations when urinating, burning and itching around opening of urethra
Rare: pain and swelling in testicles |
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What is the treatment of Chlamydia?
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antibiotics: single dose of azithromycin
week of doxycycline |
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What causes TSS?
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Staphylococcus aureus and Streptococcus pyogenes.
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Desribe Staphylococcus aureus
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Gram+ spherical
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What is the cause of infection with TSS?
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superantigen exotoxins called superantigen TSS toxin-1.
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What are the symptoms of Toxic shock syndrome?
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localized pain, flu-like symptoms fever, chills, myalgia, nausea, vomiting, diarrhea, confusion) Shock within 4-8 hours.
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Signs of severe TSS?
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hypotension, renal impairment, coagulopathy, liver abnormalities, acute respiratory distress syndrome, tissue necrosis, rash.
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How is Toxic Shock Syndrome treated?
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antibiotics, susually semisynthetic penicillins
Possibly blood transfusion and IV |
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What is the causal organism of botulism?
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Clostridium botulinum
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Describe Clostridium botulinum
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Rod shaped, gram+, produces endospore
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What kind of toxin is produced by Clostridium?
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neurotoxin which affects neuromuscular junctions.
eight different toxins, four are dangerous to humans |
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Which neurotransmitter is affected by the Clostridium neurotoxin?
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Acetylcholine.
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How is Botulism transmitted
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Contaminated food, honey, crushing wounds can become infected
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How long does it take for symptoms of botulism to appear?
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6 hours to 10 days
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What are the symptoms of Botulism?
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Paralysis of muscles in flaccid state.
small eye muscles, larynx and pharynx, respiratory muscles |
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How is Botulism treated?
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Polyvalent antitoxin
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What is the main causal organism of Gas Gangrene?
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Clostridium perfringen
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How is gas gangrene transmitted?
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spores usually acquired through wound or surgery.
Usually in areas of dead tissue or poor blood flow |
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How does Clostridium perfringen spread through the host?
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Secretes exotoxins and enzymes (lipases, proteases, and collagenases)
Creates gas as result of fermentation |
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What are the symptoms of gas gangrene?
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After 12-48 hours
Crepitant tissue, blackening, foul odor, high fever, shock, tissue destruction |
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How is gas gangrene treated?
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penicillin
surgical removal of dead tissue possibly hyperbaric chamber |
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What is the causal organism of Tetanus?
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Clostridium tetani
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Describe Clostridium tetani
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Anaerobic, Gram+, spore forming bacilli
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What is the exotoxin produced by Clostridium tetani?
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tetanospasmin
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How does the exotoxin of tetanus affect the host?
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Enters through wounds
binds with CNS Leads to rigid paralysis |
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What are complications of Tetanus?
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laryngospasms, fractures, hypertension, nosocomal infections, pulmonary embolism, aspiration pneumonia, death
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What are the treatments for Tetanus?
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Sedatives, muscle relazants, penicillin, antitoxin, reduce external stimuli
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Prevention for tetanus
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tetanus toxoid, DTP
Td |
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What is the causal organism of Diptheria?
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Coreybacterium diptheriae
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Describe C. diptheriae
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Irregular nonsporring Gram+ rod
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How does diptheria affect cells?
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Produces a toxin that inhibits protein synthesis.
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How is diptheria transmitted?
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inhaling droplets of respiratory secretions or direct physical contact
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progression of diptheriae
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adheres to local tissues of the throat.
produces different pili toxin kills cells, spreads through the body and affects heart, kidneys, and nervous system |
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What are the symptoms of diptheria?
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2-4 days after exposure: sore throat, low fever, pseudomembrane on tonsils, pharynx, nose
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What are possible complications of diptheria?
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Constriction of airways, myocarditis, polyneuritis, other systemic effects
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How is diptheria treated?
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antibiotic such as erythromycin or clindamycin
plus an antitoxin. |
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How is Diptheria prevented?
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DTP
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What is the causal organism of Tuberculosis?
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Mycobacterium tuberculosis
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How does M. tuberculosis reproduce?
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Uses white blood cells, then macrophages and lymphocytes,
then lyses the cells. |
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How long can M. Tuberculosis live in dried sputum?
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6-8 months!
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How is tuberculosis spread?
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airborne,
Requires weakened immune system |
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Describe Tuberculosis.
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chronic disease.
systemic: lungs most common, but alos other organs and bones. |
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What are the symptoms of TB?
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Pneumonia-like symptoms, hemorrhage in lungs, erosion of bones, problems with other organs.
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What are the treatments for TB?
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Isoniazid and Rifapin
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What is the prevention for TB?
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BCG vaccine
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What is the causal organism of leprosy?
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Mycobacterium leprae
-prefers cooler parts of the body can destroy peripheral tissue, skin, and mucous membranes |
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How is Leprosy transmitted?
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Not highly contagious.
can be spread through extensive contact. 90-95% of people are immune |
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What are the symptoms of leprosy?
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skin lesions, unexpected loss of eyelashes, loss of peripheral nerves, hypopigmentation.
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How is leprosy treated?
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multi-drug treatment of clofazimine, rifampin, and dapsone
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Describe Escherichia Coli
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Gram- bacillus.
One strain produces shiga toxin. |
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Progression of E. Coli in the body.
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Bacteria adhere to intestinal wall, toxins are carried throughout the body on weak WBCs.
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What are the symptoms of E. Coli food poisoning?
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Extreme abdominal pain, diarrhea, vomiting, eventually diarrhea becomes bloody.
Damage to vital organs |
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How is E. coli food poisoning treated?
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No antibiotics. Rehydration only.
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Classes of Diseases.
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inherited, congenital, degenerative, nutritional deficiency, endocrine, mental, immunology, neoplastic, iatrogenic, idiopathic
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Inherited disease
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caused by errors in genetic information
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congenital disease
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structural and functional defects present at birth
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Degenerative disease
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disorders that develop as aging occurs.
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nutritional deficiency
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lower resistance + contributes to severity of the disease
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endocrine disease
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excess or deficiency of hormones
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mental disease
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can be caused by an emotional nature of infections
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immunological disease
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caused by malfunction of immune system
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neoplastic disease
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abnormal cell growth that leads to formation of growths
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iatrogenic disease
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caused by medical procetures/treatments
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idiopathic disease
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cause is unknown
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criteria for classifying bacteria
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morpholgy, staining, growth, nutrition, physiology, biochemistry, genetics, serology, phage typing, sequence of bases in rRNA, protein profiles
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morphology
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size and shape of cells, arrangements
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staining
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gram+, gram-, or acid-fast
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growth
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characteristics in liquid/solid cultures; development of pigment
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nutrition
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qutotrophic, heterotrophic, fermentation products, energy sources, etc.
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physiology
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temperature, pH, oxygen, salt
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biochemistry
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nature of cellular components
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genetics
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% of DNA bases
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serology
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slide agglutination
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phage typing
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susceptibility to a group of bacteriophages
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