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68 Cards in this Set
- Front
- Back
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What type of organism is Brucella?
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Aerobic, facultative intracellular, unencapsulated coccobacillus found alone or in pairs.
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Which animals are reservoires for Brucella?
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Goats
Sheep Cattle Pigs Dogs |
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How is Brucella transmitted to humans?
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Ingestion of contaminated, unpasteurized milk products or through cuts and skin abrasions
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Which cells does Brucella typically infect?
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Macrophages of the reticuloendothelial system
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What is the incubation period for Brucella?
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Several weeks; but can range from 5 days to months.
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What is the major virulence factor of Brucella?
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Lipopolysaccharide (LPS)
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What is the host response to Brucella infections?
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Granulomatous, with focal abscess formation..
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What are the clinical manifestations of Brucella infection?
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1) Undulating fever
2) Flu-like symptoms including myalgias, anorexia, gastrointestinal symptoms, and headache. |
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What is the name for this constellation of symptoms with Brucell infection?
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Brucellosis
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How is Brucella infection diagnosed?
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Serologic titers for antibody greater than 1:160
Specimen cultures taking up to 1 month for growth. |
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How is Brucella treated?
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Doxycycline and gentamycin for 6 weeks.
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What type of organism is F. tularensis?
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Wild animals, including rabbits, deer and rodents.
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How is F. tularensis transmitted to humans?
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By vectors such as ticks, lice, and mice, or by contact with animal hide.
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How does F. tularensis present clinically?
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1) Ulcer at site of infection
2) Lymphadenopathy at multiple sites 3) Flu-like symptoms including fever, chills, headache, malaise, and anorexia. |
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What is the name for this constellation of symptoms caused by F. tularensis?
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Tularenmia
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What is another name of tularemia?
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Rabbit or deerfly fever.
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What other disease presents with similar symptoms and must therefore be considered in the differential diagnosis?
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Lyme disease
However, it presents with a rash and not an ulcer. |
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What are less-common symptoms of F. tularensis infection?
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Conjunctivitis
Pneumonia Pharyngitis |
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How is F. tularensis infection diagnosed?
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History of possible exposure confirmed with serologic studies including enzyme-linked immunoabsorbent assay.
Rarely cultured from blood. |
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What is an important ingredient of an F. tularensis growth medium?
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Cysteine to provide a sulfhydryl source.
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What is the treatment for F. tularensis?
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Streptomycin or gentamycin
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What is the structure of Y. pestis?
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Encapsulated small rods or coccobacillus
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Which animals are reservoirs for Y. pestis?
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Prairie dogs
Rats Squirrels |
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Which is the predominant reservoir in the US for Y. pestis?
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Prairie dogs
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How is Y. pestis transmitted to humans?
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Fleas
Respiratory droplets Ingestion of contaminated human tissue |
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Does Y. pestis replicate in humans?
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NO
humans are dead-end hosts |
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What does it mean that humans are dead-end hosts for Y. pestis?
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Dead-end hosts accidentally become infected and do not participate in the life cycle of the pathogen
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What is the incubation period for Y. pestis?
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2-8 days
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How does the virulene of Y. pestis compare to other organisms?
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It is highly virulent:
1 to 10 organisms are sufficient to elicit disease |
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What are five major virelence factors of Y. pestis?
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1) F-1 envelope antigen confers antiphagocytic properties
2) Endotoxin 3) Exotoxin 4) V antigen 5) W antigen |
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What are three clinical manifestations of Y. pestis?
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Bubonic plague
Pneumonic plague Meningitic plague |
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What are the symptoms of bubonic plague?
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Buboes
Fever chills Headache Myalgias Weakness |
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What are buboes?
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Swollen, painful, sometimes weepy lymph nodes typically found in the groin, axilla, and neck
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What are the clinical manifestations of pneumonic plague?
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Purulent pneumonia
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What are the endotoxin-related symptoms of plague?
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DIC
Septic shock Cutaneous hemorrhages Hypotension |
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What is a complication of disseminated infection?
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Plague meningitis
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How is Y. pestis diagnosed?
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Clinical presentation
Gram stain Culture on MacConkey or blood agar |
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How does Y. pestis appear on Gram stain?
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Rods or coccobacilli with bipolar staining.
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What does bipolar staining mean regarding Y. pestis?
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Staining on either end of the organism with a central clear area.
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What is the treatment for Y. pestis?
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Streptomycin is best, but gentamycin and tetracycline are alternatives.
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What is the treatment for plague meningitis?
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Chloramphenicol, because of good CNS penetration.
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What is the mortality rate of untreated bubonic plague?
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50%
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What is the mortality rate of untreated pneumonic plague?
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Almost always fatal.
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What type of vaccine is available for Y. pestis?
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Killed vaccine for those at high risk
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What is the structure of P. multocida?
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Encapsulated coccobaccilus or rods
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What are the oxygen requirements of P. multocida?
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Facultative anaerobe
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Which animals are reservoirs for P. multocida?
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Mamals and birds
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How is P. multocida transmitted to humans?
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Animal bites
Cat scratches Rarely by nasopharyngeal colonization. |
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What are the clinical manifestations of P. multocida infections?
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Wound infection or cellulitis near the site of inoculation with lymphadenitis, fever, local osteomyelitis, or arthritis.
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What is the concern associated with suturing anima bites?
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Sutures provide a substrate for growth of P. multocida, which is common in animal bites.
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What is the gold standard for diagnosis of P. multocida infection?
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Culture on blood agar.
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How does P. multocida appear on Gram stain?
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Coccobacilli or rods with bipoar staining.
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How is P. multocida infection treated?
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Penicillin along with wound cleaning/debridement for soft-tissue infections or surgical drainage for deeper infections.
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What type of organism is Bartonella?
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Facultative, intracellular, slight curved rods.
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What are three species of Bartonella that cause disease in humans?
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1) B. henselae
2) B. quintana 3) B. baciliformis |
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What disease does B. henselae cause?
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Catscratch disease and bacillary angiomatosis.
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How does catscratch disease present?
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Abscesses at site of cat scratch or bite followed by fever and lymphadenopathy.
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What is bacillary angiomatosis?
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Disease of small blood vessels of skin and internal organs usually seen in immunocompromised persons
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What disease does B. quintana cause?
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Trench fever
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How does trench fever present clinically?
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Mild
Relapsing fever Maculopapulary rash |
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What is the reservoir for B. quintana.
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Humans
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How is B. quintana transmitted?
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Human body louse
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What disease does B. bacilliformis cause?
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Oroya fever
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How does oroya fever present clinically?
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Infectious anemia
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Why does oroya fever present with infectious anemia?
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The bacteria destroys red blood cells and damages the liver and spleen.
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How is B. bacilliformis transmitted?
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Sandfly
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Where does B. bacilliformis infection commonly occur?
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South America
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What antibiotics are used to treat Bartonella infections?
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Azithromycin or
Rifampin plus Doxycycline |
