Anaerobes & Zoonotic Infections Flashcards
Which of these is NOT a characteristic of anaerobic infections?
A. they are caused by both gram- and gram+ bacteria
B. they are catalase positive
C. they are associated with a putrid odor
D. they are commonly accompanied by infections with facultative anaerobes
E. not all anaerobes are killed by oxygen
B.
Anaerobes lack enzymes like catalase that detoxify oxygen and its byproducts, as well as cytochrom systems for oxygen metabolism.
Which of the following statements about the Clostridium strain of bacteria is FALSE?
A. it is similar to bacillus anthracis in that it forms spores that, upon germination, produce toxins
B. causes food poisoning when preformed toxin is ingested
C. C. tetani forms spores at the terminal ends of their cells
D. causes soft tissue infections of varying severeties and is commonly treated with penicillin
E. all strains of Clostridium are gram negative
E.
All strains are gram positive.
Which strain of Clostridium produces an alpha toxin that causes massive hemolysis, tissue and vascular destruction, and myocardial dysfunction:
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
C.
Which strain of Clostridium produces a toxin that is encoded by heat labile A-B neurotoxin?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
B
Which strain of Clostridium is associated with antibiotic depletion of normal flora, allowing overgrowth?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
A
Which strain of Clostridium produces a lethal toxin that has been used as a muscle relaxant for foot deformitites, spasticity, and tennis elbow?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
D.
Which strain of Clostridium is treated with metronidazole and may require a stool transplant?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
A
Which strain of Clostridium produces an enterotoxin and a cytotoxin?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
A.
Toxin A (enterotoxin) stimulates infiltration of neutrophils into the ileum and causes inflammation. Toxin B (cytotoxin) glycosylates G proteins resulting in loss of cytoskeletal integrity and death of enterocytes.
A 40 year old woman comes to the clinic with blurred vision and slrred speech. She is afebrile. She is noted in her neighborhood for her home-canned vegetables and fruits and ingested some of her stock after they had been stored for a long period of time (several months). What is the likely cause of her illness?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
D.
She should be treated with antiserum immediately and gastric lavage. Ventilatory support if necessary.
A 25 year old man fell from his motorcycle and suffered a compound fracture of his femur. The fracture was surgically reduced and the wound debrided. 48 hours later he developed a fewver and the wound area became necrotic. A foul-smelling odor was perceived originating from the wound. Anemia and a white blood count of 2,800 were found. A gram stain of the exudate showed large gram-positive rods. Colonies grew on blood agar incubated anaerobically but not aerobically. What is the likely cause of her illness?
A. C. difficile
B. C. tetani
C. C. perfringens
D. C. botulinum
C.
Alpha toxin is causing the necrosis.
organism that causes bubonic plague and are transmitted by infected rats
Yersinia pestis
Which of the following statements regarding Yersinia is FALSE?
A. Not all of the Yersinia strains are zoonotic infections
B. All species are members of Enterobacteriacea
C. They are all gram negative rods that utilize glucose as a carbon source
D. They are facultative intracellular parasites
E. Bubonic plague is the only form of inter-human transmission by aerosol spread and has a high mortality rate
E.
It is Pneumonic plague, a progression of bubonic plague, that is spread this way. Bubonic plague itself is spread indirectly from rats to humans by fleas (vectors). Fleas can also serve as a host reservoir.
All of the following are virulence factors of Yersinia pestis EXCEPT:
A. LPS
B. F1 antigen
C. Yops
D. Antiphagocytic capsule
E. Invasin
E.
This is a virulence factor of Y. enterocolitica.
major reservoir for this bacteria are infected rabbits in central US - bacteria have antiphagocytic capsule and can live inside macrophages
Francisella tularensis
Treat with streptomycin.
Which of the following statements about Pasteurella multocida is FALSE?
A. it is a gram negative and oxidase positive part of the normal flora of many domestic pets
B. infection transmitted through bites and scratches resulting in lymphadenitis and cellulitis
C. because of resistance development, penicillin should be given only if an infection develops following an animal bite or scratch
D. may cause septicemia in immunocompromised individuals
E. can be cultured on blood agar in vitro
C.
These organisms are easily treated with antibiotics (penicillin) and are given prophylactically following a bite or scratch.
