Enterobacteriaceae Flashcards
What disease patterns do Yersinia pseudotuberculosis and Y. enterocolitica cause in small animals, pigs, and birds?
Lymphadenitis, gastroenteritis, and septicemia
What metabolic feature is useful in identifying bacteria belonging to the family Enterobacteriacae?
They are oxidase negative
(lack cytochrome c oxidase)
Why are penicillins generally not effective in treating infections caused by Gram (-) bacteria?
Penicillins are lipid soluble and remain “stuck” in the outer lipopolysaccharide layer
How are Yersinia infections treated and managed?
Antibiotics- tetracycline, aminoglycosides
Y. pseudotuberculosis pestis- flea and rodent control
What disease patterns does E. coli cause in animals?
Entero- and non-toxigenic diarrhea
Invasive disease if able to travel to secondary sites in the blood, endotoxemia
Oppertunisitic UTIs and mastitis due to fecal contamination
What is a common pathogenic mechanism in enteropathogenic E. coli infections?
Disrupts the normal intestinal architecture- causes intestinal epithelium to grow additional processes to hold the bacteria
This change damages the intestinal epithelium and they lose their absorptive capacity
What is the host range of Shigella?
Which disease pattern does it cause in these animals?
Host range restricted to primates
Causes dysentery
How are E. coli infections treated and prevented?
Should antibiotics be used?
Supportive care to correct fluid/electrolyte abnormalities
Antibiotics are controversial- disrupt other microflora, E. coli tends to be multi-drug resistant
Can vaccinate cattle and swine to transfer passive immunity
How are Shigella infections treated and prevented?
Treat with antibiotics and supportive care
Prevent with sanitation
What disease processes do members of the genus Salmonella cause in ruminants and horses?
Diarrhea, septicemia, pneumonia
S. enterica var. paratyphi causes paratyphoid fever
How does the Type Three Secretion System (TTSS) increase the virulence of Salmonella?
Causes “ruffling” of intestinal epithelium- disrupts tight junctions
Can become intracellular
How are Salmonella infections treated and prevented?
When should antibiotics be used?
Uncomplicated diarrheal diseases/enteritis- supportive care, antibiotics usually not necessary
Systemic disease- use antibiotics after performing susceptibility test
Prevention- sanitation
What disease patterns does Y. pseudotuberculosis pestis cause?
Septicemic , bubonic, and/or pneumonic plague
Lymphadenitis
