Exam 4: pleomorphic gram - rods and other odd gram - bacteria Flashcards
What gram negative rod has bipolar staining pattern, is motile and part of the enterobacteriae family?
yersinia (pestis and enterocolitica)
What is the reservoir for yersinia pestis?
rats
What is the vector for yersinia pestis?
fleas
Bubonic plague is caused by what bacteria?
yersinia pestis
What is the pathogenesis of the bubonic plague and its progression to septicemic plague?
engulfed by macrophages where multiply and are carried to lymph nodes. Lymph nodes become necrotic and bacteria enters blood. Once the bacteria is in the blood it is called septicemic plague and causes shock and disseminated intravascular coagulation
What is pneumonic plague?
infection of the lung from the blood stream with yersinia pestis that occurs in 10-20% of cases of septicemic plague that is always fatal within a few days
What gram negative rod, with bipolar staining, that produces a heat stable enterotoxin that leads to severe gastroenteritis from ingesting contaminated food or water?
yersinia enterocolitica
What curved gram negative rod has a single polar flagellum that appears to vibrate?
vibrio cholerae
What is the pathogenesis of V. cholera?
they are killed by acid, so a large number must be ingested before enough survive stomach passage. Those that do pass the stomach will adhere to mucosa and multiply. They do not invade cells. They produce enterotoxin called Choleragen.
What spiral shaped bacterium has a unipolar or bipolar flagella and is a major cause of gastroenteritis in the US but is self limiting and therefore under reported?
campylobacter
What spiral shaped bacterium has a unipolar sheathed flagella and is the 2nd leading cause of gastric/duodenal ulcers by producing urease which allows organism to create alkaline environment in stomach?
helicobacter
What are the main obligate anaerobic gram negative bacteria?
bacteroides fragilis
fusobacterium
What obligate anaerobic gram negative bacteria is rod shaped, part of normal flora, does not possess endotoxin or capsule and is an opportunistic pathogen associated with ovotubal abscesses and periodontal disease?
bacteroides fragilis
What long rod bacteria with tapered ends is part of normal flora and acts as opportunistic pathogens causing infections such as aspiration pneumonia?
fusobacterium
What obligate aerobic gram negative rod is the epitome of opportunistic pathogen because is does not infect healthy patients but infects any tissue in weakened patients (burn victims, AIDS patient, cystic fibrosis?
pseudomonas aeruginosa
