Unit 3: Mannheimia and Bibersteinia Flashcards
Is Mannheimia haemolytica trehalose negative or positive?
it is trehalose negative
What other species belong to the Mannheimia genus but are of minor importance as causes of disease?
M. glucosida, M. granulomatis, M. ruminalis, and M. verigena
Mannheimia haemolytica is considered to be the most important bacterial cause of _____ _____ in _____ and ______ and also causes ______ in sheep.
respiratory disease; cattle; sheep; mastitis
On gram stain, what does Mannheimia haemolytica look like?
gram negative, small coccobacillus
How does Mannheimia haemolytica grow on MacConkey’s?
it is supposed to grow but isolates frequently do not grow or grow only poorly
What do colonies of Mannheimia haemolytica look like?
it forms a smaller colony than P. multocida, lacks the musty odor and is hemolytic but often with a very narrow zone of complete hemolysis
Is Mannheimia haemolytica lactose positive or negative?
positive
Is Mannheimia haemolytica indole positive or negative?
negative
What main type of toxin does Mannheimia haemolytica produce and what does it do?
a RTX toxin which is toxic for leukocytes and platelets of ruminants by forming pores into the leukocyte
What other virulence factors does Mannheimia haemolytica produce that are involved in induction of pneumonia?
lipopolysaccharide, capsular polysaccharide, fimbriae, glycoprotease, neuraminidase, and membrane proteins
What is the natural habitat of Mannheimia haemolytica?
upper respiratory tract of cattle and sheep
How is Mannheimia haemolytica transmitted?
ingestion or inhalation
What does Biotype A serotype 1 of Mannheimia haemolytica cause in cattle?
acute fibrinous pleuropneumonia involved in the shipping fever complex (which is the leading cause of loss to the feeder cattle industry)
What does Mannheimia haemolytica cause in sheep and goats?
septicemia in newborn lambs and pneumonia in adults
Aside from pneumonia, what does Mannheimia haemolytica cause in sheep?
‘blue bag’ - gangrenous mastitis
What products have been used to stimulate an immune response against Mannheimia haemolytica in cattle?
killed bacterins and modified live vaccines
What cells are important in the defense of the lower respiratory tract?
phagocytic cells - alveolar macrophages and neutrophils
At low levels, what is the function of the Mannheimia haemolytica cytotoxin?
it inhibits the function of alveolar macrophages and neutrophils
At high levels, what is the function of the Mannheimia haemolytica cytotoxin?
the cytotoxin is able to kill these same cells
What is the pathogenesis of disease caused by the Mannheimia haemolytica cytotoxin?
When the neutrophils and alveolar macrophages in the lungs are killed they release their lysosomal enzymes onto the surface of the cells in the alveolar space causing inflammation. The inflammation causes the pulmonary tissue to be non-functional. If the area of inflammation is large enough then the animal can go into respiratory distress. The organism manipulates the immune system so that the inflammatory mediators and activated immune-effector cells end up being a major contributor to the disease process
Some believe a successful humoral immune response to a Mannheimia haemolytica infection requires antibody against the ____ and ____ ____ _______.
cytotoxin and cell surface components
Is Bibersteinia trehalosi trehalose positive or negative?
positive
Bibersteinia trehalosi produces a toxin almost identical to what other bacteria?
Mannheimia haemolytica
In cattle, what does Bibersteinia trehalosi cause?
severe respiratory disease in dairy cattle and more recently associated with feedlot pneumonias
What does Bibersteinia trehalosi cause in sheep?
septicemia in feeder lambs via the esophagus
What does Bibersteinia trehalosi cause in goats?
respiratory disease
