micrococcacea Flashcards
family
micrococcaceae
genera
microccocus, staphylococcus, planococcis, stomacoccus (rothia)
free living saprophyte
planococcus
free living saprophyte, rarely cause human infection
micrococcus
normal flora of primates and other mammals
stomatococcus and staphylococcus
all, except ______ have been isolated from clinically significant sources
planococcus
these genus are always encountered in clinical sources or specimen
micrococcus and staphylococcus
can be isolated from clinically significant sources
microccocus
stomatococcus
staphylococcus
exists in the environment and doesn’t require or infect a host
planococcus
mostly associated with infections
staphylococcus
general characteristics (micrococcaceae)
-catalase positive, gram positive cocci
-resident flora of the skin and mucous membranes
-ubiquitous
-infections are directly or indirectly transmitted
differential test for micrococcus and staphlyococcus
Lysostaphin susceptibility test
Modified Oxidase test
Bacitracin susceptibility test
oxidation/fermentation (OF) test
incubation temp and time for Lysostaphin susceptibility test
35 - 37 deg C, 2 hours
antibiotic type of chemical that will destroy glycine rich peptide bond
lysostaphin
staphylococcus cannot grow properly in the presence of
lysostaphin
reagent use for modified oxidase test
Modified oxidase reagent:
6% tetramethyphenylenediamine hydrochloride in dimethyl sulfoxide
or
Microdase disk ( with impregnated Mod. oxidase reagent)
results in modified oxidase test can be observed
within 5-10 seconds
positive and negative result for Modified oxidase test
positive: micrococcus ( contains cytochrome oxidase enzyme)
negative: staphylococcus
test is used to differentiate micrococcus and stomatococcus from staphylococcus to 0.04 units of bacitracin
Bacitracin susceptibility test
_____ of bacitracin inhibits growth of ________ ,while having no effect on ______.
0.04 units, micrococcus/stomatococcus, staphylococcus
zone of inhibition should be _____to indicate susceptibility and are typical of : micrococcus
greater than 10mm
an organism that typically produce no zone of inhibition in bacitracin susceptibility test
staphylococcus
testing if the organism can utilize the carbohydrate on certain environmental conditions
Oxidation/fermentation test
uses two tubes of Hugh & leison’s medium
OF test
in one tube of OF test the medium is ________
covered with vaseline
both tube of OF test has what type of carbohydrate
glucose
what dye is used for the ph indicator for OF test
bromthymol blue
incubation temp and time duration
35 - 37 deg C and 18-24 hours
alternate source of energy for asaccharolytic or non-fermentative organisms
peptone
if the medium didnt turned yellow in a close system, what does it indicate
the organism can only utilize the carbohydrate in the presence of oxygen
type of organisms that utilizes the carbohydrate in the presence of oxygen
oxidizers
if the organism is capable of utilizing the carbohydrate with and without oxygen even in close tube
fermenter
with or without oxgyen and no carbohydrate was utilize
nonutilizer
will produce acid only in the open tube (without vaseline)
oxidizer (micrococcus)
it will produce acid in both tubes
fermenter (staphylococcus)
result if Micrococcus was OF tested, what color does it indicate and interpret
open: yellow
close: green
interpretation: oxidative; strictly aerobic
result if Staphylococcus was OF tested, what color does it indicate and interpret
open: yellow
close: yellow
Interpretation: oxidative and fermentative; facultative anaerobic
result of lysostaphin susceptibility test (200ug/ml)
susceptible: staphylococcus
resistant: micrococcus
result of bacitracin susceptibility test
susceptible: micrococcus
resistant: staphylococcus
result in furazolidone (100ug)
susceptible: staphylococcus
resistant: micrococcus
result in lysosome (50-mg)
susceptibility: micrococcus
resistant: staphylococcus
characteristic of Staphylococci
gram-positive cocci in clusters
catalase-positive
morphology of staphylococci
spherical cell (0.5-1.5mm) that appear singly, in pairs, and clusters( depends on the plane of division of the organism)
most common cause of food poisoning
S. aureus
principal virulence factor of S. aureus
coagulated/staphylocoagulase
can be cultivated by adding _____ to _____
7.5% to 10% NaCI
Some strains produce golden yellow colonies due to the pigment they
produce known as ___________
Staphyloxanthin
Most colonies beta-hemolytic (halo around the colonyent are presnt
beta-hemolytic
