Yersinia Flashcards
– causative agent of plague
Yersinia pestis
Yersinia
3 human pathogens
Yersinia pestis
Yersinia pseudotuberculosis
Yersinia enterocolitica
Implicated in sporadic cases of gastroenteritis, mesenteric lymphadenitis especially in children, and generalized septicemic infections in immunocompromised hosts.
§ Yersinia pseudotuberculosis
§ Yersinia enterocolitica
– has been a cause of diarrhea outbreaks in numerous communities and it has been seen to mimic appendicitis.
Yersinia enterocolitica
– flea vector (most common and effective vector of Yersinia pestis)
§ Parasite of the rodent_____– a black rat, as the main rodent host of Yersinia pestis
Xenopsylla cheopis (oriental rat flea)
Rattus rattus
Microaerophilic, gram negative, short, plump bacillus
Shows marked bipolar staining when stained with “Wayson Stain”- cells having a characteristic “Safety Pin” appearance
Yersinia pestis (Plague bacillus)
Plague – occurs in three distinct forms:
– most common form of the disease, results from the bite of a flea, or by direct inoculation of an open skin would by plague-infected material.
_____, lymph nodes filled with inflammatory cells that can ulcerate, can be several in diameters incentimeters
• Bubonic plague
Plague – occurs in three distinct forms:
– results from the hematogenous dissemination of the organism, following the damaged of the lymph nodes in patients with bubonic plague.
– occurs in patients without buboes as primary infections.
• Secondary septicemic plague
§ Primary septicemic plague
Plague – occurs in three distinct forms:
– results form the dissemination of the organism to other organ systems such as the lungs, brain, liver, and spleen, with days- near and hemoptysis, plague meningitis, and hepatic and splenic abscesses
• Secondary pneumonic plague
• If Yersinia pestis is to be weaponized– its optimal release would be via aerosols, and most patients would develop…
primary pneumonic plague
Found in a wide variety of animals, including domestic swine, cats, and dogs.
Mode of transmission – contact with household pets. Transmission via pigs has been greatly emphasized in Europe
Human infections – most often occurs after the ingestion of contaminated food, often pork, and vacuum packed deli meat, lamb, chicken, and possibly milk and water.
Yersinia enterocolitica
The ability of the organism to survive in cold temperatures – is a potential risk of
transmitting infections via consumption of refrigerated foods (refrigeration is
ineffective as a measure to control the infection)
In transfusion medicine, reports of the transmission of Yersinia enterocolitica from contaminated packed red blood cell components have been recorded
Yersinia enterocolitica
erythema nodosum.
Yersinia enterocolitica
Yersinia enterocolitica
Cold enrichment of fecal specimens for Yersinia enterocolitica
a. Fecal material is inoculated into _____and kept at 4C for 1-3 weeks with weekly subculture to selective agar for Yersinia.
b. Subculture can be performed using____ selective for Yersinia that contains cefsulodin, irgasan,
novobiocin, bile salts, and crystal violet as inhibitory agents
c. CIN – better than____ in inhibiting normal colon microbiota and
provides better opportunity for the recovery of Yersinia enterocolitica
in feces.
d.______, a modified version of CIN that contains mannitol as differential agent.
isotonic saline
Cefsulodin –Irgasan-Novobiocin
(CIN) –
MAC
YSA – Yersinia-selective agar
Similar to Yersinia pestis for being a disease primarily of rodents,
particularly guinea pigs.
Birds are natural reservoirs.
Yersinia pseudotuberculosis
