Chapter 19 Enterobacteriaceae Flashcards
Exam 3
What are the general characteristics of Enterobacteriaceae?
Ferment glucose
Reduce nitrate to nitrites
Oxidase negative
What is the morphology of Enterobacteriaceae
Gram-negative coccobacilli or straight rods
True or false. Enterobacteriaceae is facultatively anaerobic
True
What is the macroscopic morphology of Enterobacteriaceae
Large moist, gray colonies
Bile salts and crystal violet inhibit gram-positive
It is selective and differential
Lactose fermentation is differential
What agar plate is this?
MacConkey MAC agar
Selective and differential
Methylene blue inhibits gram-positive
Lactose and sucrose fermentation is differential
What agar plate is this?
Eosin-methylene blue (EMB) agar
Selective and differential
Bile salts inhibit gram-positive, some gram-negative
Lactose and sucrose fermentation is differential
What agar plate is this?
Hektoen enteric (HE)
Green to blue color with H2S gas creating a black ppt is what type of enterobacteria
Salmonella on HE agar
Green to blue green color is what type of enterobacteria
Shigella on HE agar plate
Selective and differential
Has Sodium Deoxycholate
What type of agar plate is this?
Xylose lysine deoxycholate (XLD) agar
Sodium Deoxycholate does what
Inhibits gram-positive and some gram-negative
On the XLD agar plates, Escherichia coli and Citrobacter will produce what kind of colonies?
Yellow colonies
Yellow colonies on the XLD agar means that fermenters of those not producing what?
lysine decarboxylase
On XLD agar what kind of colonies will shigella produced?
Colorless or red colonies
On XLD agar what colonies will Salmonella will produced
Red colonies with black centers
What does adherence mean?
Prevent being removed from tissues
Enterobacteriaceae has what type of antigens?
O antigen
H antigen
K antigen
Where is the O antigen located at?
In the cell wall and it is the heat stable antigen
H antigen is the what type of antigen?
Flagellar and it is heat stable
K antigen is what type of antigen
Capsular antigen which is heat labile
Dry pink colonies
Beta-hemolysis on blood agar plate (BAP)
Motile
Possess adhesive fimbriae and sex pili
Possess O, H, K antigen
is what type of Enterobacteriaceae
E.coli
What is the most common cause of UTIs?
Uropathogenic E.coli
Uropathogenic E.coli usually originate from where?
In the large intestine as normal flora
What can cytolysins do
Kill immune cells and inhibit phagocytosis
Klebsiella belong to what tribe
Klebsielleae
Where can the tribe members be found at
In the intestinal tract of humans and animals, in soil, water, and plants
Klebsiella pneimoniae can be in the
lower respiratory tract infection of hospitalized patients
What is the virulence factor of klebsiella pneumoniae
polysaccharide capsule
A documented pathogen causing meningitis and bacteremia in neonates from powdered infant formula
Cronobacter sakazakii
Opportunistic pathogens associated with outbreaks in health care settings
serratia species
What species is this of Serratia
Pink-to-red pigment when growing at room temp
Usually most clinically relevant
Nosocomial infections of the Urinary tract, respiratory tract, and bacteremia
S. marcescens
What type of species of Serratia is this?
Dirty, musty odor resembling that of rotten potatoes
S. odorifera
What type of bacteria is this?
Linked to gastroenteritis and occasionally isolated from stool cultures
Hafnia alvei
P. mirabilis and P. vulgaris generally produce swarming on what type of laboratory media. What kind of smell is produce
Burnt chocolate odor
What Morganella species can cause UTI species, is a possible agent of diarrheal disease and cause of neonatal sepsis
M. morganii
P.rettgeri can cause what type of outbreaks
Urinary tract pathogen and occasionally nosocomial outbreaks
What is the most common citrobacter species
C. freundii
What are three major clinical types of plesiomonas that cause gastroenteritis
Watery or secretory diarrhea
Chronic disease that lasts from 14 days to 2-3 months
Resembles colitis
True of false- Plesiomonas is oxidase positive
True
Is direct microscopic examination helpful in differentiating the species of enterobacteriaceae?
No it is not very helpful
Characterized by prolonged fever and intermittent bacteremia
Nontyphoidal bacteremia
This type of bacteria appear clear, colorless, nonlactose-fermenting on MAC and on HE or XLD and does not produce H2S
Shigella
Lack H antigens, has K antigen and O antigens are separated by serologic grouping A through D
Shigella
Most serious infection (developing countries) is what type of shigella species
S. dysenteriaae group A
Second most common isolate in the United States is what type of shigella species
S. flexneri Group B
This type of shigella is more common in developing countries
S. boydii (Group C)
This type of shigella is most common isolate in the United States
S. sonnei Group D
Shigella dysentery invade what type of tissues?
Colonic tissues
What is the causative agent of plague?
Y. pestis
Gram-negative coccobacilli resembling a safety pin appearance (bipolar staining)
Yersinia pestis
This type of yersinia can be acquired from contact with swine, cats, and dogs.
Yersinia enterocolytica
Gram-negative coccobacilli appearance (bipolar staining)
Y. enterocolytica
This type of yersinia is the primary pathogen of rodents, farm animals, and birds
Yersinia pseudotuberculosis
This type of media contains antimicrobials or chemicals
selective media
This media allows differentiation of bacterial species based on colony morphology
Differential media
