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Unit 7
Brucella species
Question | Answer |
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How does one acquire Brucella or "Undulant Fever"? | It is acquired by direct contact with infected material such as animal carcasses, fetal membranes, vaginal discharge, mucous membranes, or unpasteurized milk. Meat packing plant workers are at risk. |
What type of blood culture bottle is used to recover Brucella? What does it consist of? | A biphasic blood culture bottle called Castaneda is needed, it contains a slant of enriched agar that is partially submerged in enriched broth. As the specimen is injected into the bottle the slant is covered. |
What conditions must be met in order to grow Brucella? how long must it incubate for? | Brucella is a slow grower so increased CO2 is needed and 21 days incubation to grow. |
What symptoms does Brucella species cause? | Local lymphadenopathy to formation of granulomas in major organs, bone or soft tissue |
How are the Brucella species differentiated? | All are oxidase positive so differentiated by increased CO2 requirements, susceptibility to bacteriostatic dyes such as thionine and basic fuchsin and by H2S production. |
What is the most commonly recovered species of Brucella in our lab? What are its characteristics? | Brucella melitensis is most commonly recovered, found in goats and sheep, does not require increased CO2, Urea variably, thionine (-), fuchsin (-), and H2S (-). |
What special precautions should be taken when working with Brucella? Why? | All suspected Brucellosis cases should be handled under a Biological Safety Cabinet or "hood" due to the aerosol mode of transmission. |
What are four different species of Brucella? | B. abortus (cows), B. suis (pigs), B. melitensis (sheep/goats), B. canis (dogs) |
What does the term "undulating fever" describe? | Normal temp. in the AM, high temp. in the PM |