RAPID IDENTIFICATION AND ANTIBIOTIC RESISTANCE DETECTION OF MICROORGANISM Flashcards
Where is S. aureus found?
In the nasal passages
is the most common to become pathogenic
What are the biochemical reactions of S. aureus?
Catalase positive
Coagulase positive
How does S. aureus appear on gram stain?
GPCs in “grape-like” clusters
What are the growth requirements for S.aureus?
aerobic and facultative anaerobe, grows= best at 35 °C in ambient
air or a CO2-rich environment
How does the colony morphology for S. aureus appear?
soft, opaque or pale gold, and circular on sheep blood agar, most
colonies are beta-hemolytic, and colonies present with a yellow halo on mannitol salt agar
Where is S. epidermidis found?
most prevalent skin flora, attach to the outer layer of skin,
the epidermis, and inhibit overgrowth of potential pathogens
what are the biochemical reactions of coagulase negative Staph?
Catalase positive
Coagulase negative
What are the growth requirements for coag negative staph?
aerobic and facultative anaerobe, grow best at 35 °C in ambient air
or a CO2-rich environment
What is the colony morphology of S. epidermidis?
white, cohesive, raised circular colonies on tryptic soy agar, opaque,
gray, smooth, raised colonies with no hemolysis on sheep blood agar
What is the colony morphology of S. saprophyticus?
white-yellow, opaque, smooth, raised colonies with a butter-like
texture on sheep blood agar.
What are the biochemical reactions of beta-hemolytic streptococci?
Catalase −
Gas production −
Motility −
Optochin R
Bile solubility −
Leucine aminopeptidase +
Vancomycin S
What does Streptococci look like on a gram stain?
GPCs in chains
What are the growth requirements of beta hemolytic streptococci?
5–10% CO2 with vertical stabs in agar to promote beta-hemolysis
What is the colony morphology of beta hemolytic streptococci Group A?
grayish-white, transparent to translucent, matte or glossy, large zone of hemolysis
What is the colony morphology of beta hemolytic streptococci Group B?
larger than group A colonies, translucent to opaque, flat, glossy, narrow
zone of beta-hemolysis, and some strains are nonhemolytic
What is the colony morphology of beta hemolytic streptococci Group C?
grayish-white, glistening, wide zone of beta-hemolysis
What is the colony morphology of beta hemolytic streptococci Group F?
grayish-white, small, matte, narrow zone of beta-hemolysis
What is the colony morphology of beta hemolytic streptococci Group G?
grayish-white, matte, wide zone of beta-hemolysis.
What are the biochemical reactions of Enterococcus species?
Catalase −
PYR +
Gas production +
Optochin R
Bile solubility −
Bile esculin +
6.5% NaCl +
Leucine aminopeptidase +
what does the gram stain look like for enterococcus species?
GPCs in chains or pairs
what are the growth requirements for enterococcus species?
aerobic and facultative anaerobe, able to grow in temperatures
ranging between 10 °C and 45 °C
What is a “facultative” anaerobe?
an organism that can survive both with and without oxygen, preferring aerobic conditions when available
What is an “obligate” anaerobe?
an organism that can only survive in the absence of oxygen and will die if exposed to it
What is the colony morphology of enterococcus species?
large white colonies on sheep blood agar, may be alpha- or beta-
hemolytic, blackens medium of bile esculin agar during growth.
how does the gram stain appear for Candida species?
Gram-positive single yeast buds, pseudohyphae constricted but connected at
the ends, or true septate hyphae
What are the growth requirements for Candida species?
aerobic and facultative anaerobe, grow best at 25–37 °C
What does the colony morphology look like in Candida species?
creamy, white, dull, grows upward with foot-like projections from the
bottom of the colony on sheep blood agar and cream-colored, smooth, pasty colonies on
Sabouraud dextrose agar.
What are the biochemical reactions of streptococcus pneumoniae?
Catalase −
Bacitracin R
Na Hippurate −
Optochin S
Bile solubility +
Bile esculin −
6.5% NaCl −
how does streptoccus pneumoniae appear on a gram stain?
gram positive diplococci, lancet shaped
what is the colony morphology of streptococcus pneumoniae?
alpha-hemolytic, mucoid or “water drop” colonies with a convex
middle on sheep blood agar
What are the biochemical reactions of ACINETOBACTER BAUMANNII?
Oxidase −
Growth on MacConkey agar +
Motile −
Glucose oxidation +
Maltose oxidation −
Esculin hydrolysis −
Lysine decarboxylase −
Nitrate reduction −
Urea V
How does ACINETOBACTER BAUMANNII appear on gram stain?
Gram-positive/variable coccobacilli
What are the growth requirements for Acinetobacter baumanni?
aerobic and facultative anaerobe, grow best at 35 °C in ambient air
or a CO2-rich environment
What is the colony morphology of Acinetobacter baumanii?
smooth, creamy, opaque, raised on sheep blood agar, purplish hue on
MacConkey agar
What are the biochemical reactions of Enterobacteriaceae?
Oxidase −
Catalase +
Nitrate reduction +
what does the gram stain look like for enterobacteriaceae?
GNRs
what are the growth requirements for enterobacteriaceae?
aerobic and facultative anaerobe, grow best at 35 °C in ambient air
or a CO2-rich environment. MacConkey and other selective agars are incubated in ambient
air only. Yersinia pestis grow best at 25–30 °C.
what is the colony morphology of enterobacteriaceae?
large, smooth, and gray on sheep blood and chocolate agars.
Lactose fermenting species, pink on MacConkey agar of enterobacteriaceae:
❖ Citrobacter
❖ Escherichia
❖ Enterobacter
❖ Klebsiella
Non-Lactose fermenting species, pink on MacConkey agar of enterobacteriaceae:
❖ Shigella
❖ Yersinia
❖ Proteus
❖ Salmonella
what are the biochemical reactions of pseudomonas species?
Motility +
Oxidase +
Indole +
Lysine decarboxylase −
how does pseudomonas appear on gram stain?
GNRs
what are the growth requirements for pseudomonas?
obligate aerobe, grow best at 35 °C in ambient air or a CO2-rich
environment
what is the colony morphology of P. aeruginosa?
grayish white, translucent to opaque, circular with irregular edges on
sheep blood agar. Colorless, transparent, circular, on MacConkey agar. Colonies are
smooth or mucoid, if swarming occurs. Produce a grape, or corn tortilla-like odor.
