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Title: Staphylococci
Description: All about Staphylococci and its related contents.
Description: All about Staphylococci and its related contents.
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Staphylococci
College of Medical Laboratory Science
Bacteriology Lecture
Characteristics
•
•
•
•
•
Staphylococcaceae
Family ______________
Catalase_ (+)
Coagulase (+) & some are Coagulase (-) CoNS
Gram (+) cocci in singly, in pairs and in clusters
Micrococcaceae ; genus __________
Micrococcus
Resembles the family ____________
_
_
• Catalase (+)
•
Coagulase (-)
•
•
•
Rothia
mucilaginosa
Gram (+) cocci in pairs, tetrads, and, ultimately, irr •egular
clusters
• Aerococcus
Found in environment and human skin
• Alloiococcus otitis
Colonies: yellow pigment
Test
Staphylococci
Microbiology
Micrococci
Modified oxidase (Microdase)
-
Anaerobic acid production from glucose
+
Anaerobic acid production from glycerol in
the presence of erythromycin
+
-
Growth on Furoxone-Tween 80–oil red O
agar
-
+
R*
R
S*
S
S
R
Resistance to bacitracin (0
...
kristinae
and M
...
sciuri,
Catalase
+
+
±
Macrococcus
Modified oxidase caseolyticus,
- S
...
vitulus except M
...
varians
FA
A
Microbiology
Resistance to
bacitracin (0
...
saccharolyticus (obligate anaerobe)
•
•
Normal flora of skin and mucous membranes of human & animals
Colonies: medium sized (4 to 8 mm) and appear cream-colored, white or rarely light gold,
and “buttery-looking”
•
Fastidious strains requirements: CO2, hemin, or menadione
with at least 48 hrs of incubation
Organisms
Infections
Infections
•S
...
epidermidis
• nosocomial infections
S
...
haemolyticus
•
•
S
...
Enterotoxins
•
•
•
•
•
Groups A-E & G-J
Staphylococcal food poisoning A, B, D
TSS B, C, G, I
Staphylococcal pseudomembranous enterocolitis B
Heat stable exotoxins (100° C for 30 mins)
•
Interacting with TSST-1: interact with T cells
Staphylococcus aureus
Virulence factors:
2
...
Exfoliative Toxin
• Epidermolytic toxin
• Staphylococcal SSS
Ritter disease
• Bullous impetigo
Staphylococcus aureus
Virulence factors:
4
...
aureus: α, β, γ, δ hemolysins
•
•
α-hemolysin: lyse RBC, damage platelets and macrophages and causes severe
tissue damage
“hot-cold lysin”
C _ or ___________
β-hemolysin: also known a sSphingomyelinase
_________________
: acts on sphingomyelin in the plasma membrane of erythrocytes
: act in CAMP test
Staphylococcus aureus
Virulence factors:
4
...
Enzymes
• Coagulase, protease, hyaluronidase & lipase
• Staphylocoagulase
• S
...
aureus
•
hydrolyzes hyaluronic acid present in the intracellular ground substance that
makes up connective tissues, permitting the spread of bacteria during
infection
Staphylococcus aureus
Virulence factors:
5
...
Protein A
• Cellular components in cell wall of S
...
aureus: _____________________________
small- to medium-sized, nonhemolytic,
S
...
04U) on an
organism
Result:
• (+) presence of zone of inhibition around the disk
• (-) no zone of inhibition
Test
Staphylococci Micrococci Rothia
except S
...
lentus
Modified oxidase caseolyticus,
+
& S
...
kristinae
Aerotolerance
FA and M
...
04 U)
Resistance to
furazolidone (100
ug)
Resistance to
lysostaphin (200
ug/mL)
Aerococcus
Enterococcus
FA
FA
R
S
R/S
S
R
S
R
R/S
S
S
S
R
R
R
R
Workflow
Biochemical Tests
• Oxidation-Fermentation (O/F) reactions
•
•
Principle: determine whether an organism uses carbohydrate substrates to produce
acid byproducts using OF glucose medium
glucose, xylose, mannitol, lactose, sucrose, and maltose
Result:
•
•
(+) yellow medium; acid production staphylococci
(-) no change in color; no acid production micococci
except M
...
varians
S
...
auricularis
S
...
xylosus
S
...
aureus
•
(-) no fibrin clot CoNS
Workflow
Biochemical Tests
• Coagulase Test
•
•
2 forms of coagulase enzyme:
Bound coagulase/ clumping factor
•
•
•
human, rabbit, or
Slide Coagulase Test
pig plasma in EDTA
bound to the bacterial cell wall and reacts directly with fibrinogen in plasma
alteration of fibrinogen
precipitates on the staphylococcal cell
Fibrin clot (clumping of cells) (+) S
...
lugdunensis and S
...
aureus from other CoNS by the presence of the enzyme Lpyrroglutamylaminopeptidase
•
L-pyrroglutamylaminopeptidase hydrolyze L-pyrrolidonyl-β-naphthylamide/PYR
(substrate) = β-naphthylamine
β-naphthylamine + N, N-methylaminocinnamaldehyde/pdimethylaminocinnamaldehyde (reagent)
Result:
• (+) Bright red color S
...
intermedius, S
...
aureus
•
•
Workflow
Biochemical Tests
• Vogue-Proskauer (VP) test
•
•
Principle: determine the ability of some organisms to produce neutral end products
from glucose fermentation acetyl-methylcarbinol or acetoin
Result:
•
•
(+) Red color S
...
intermedius, S
...
haemolyticus & S
...
saprophyticus
Catalase
Coagulase
Micrococcus spp
...
saprophyticus
MRSA (methicillin-resistant Staphylococcus aureus)
• Penicillin-resistant (β-lactam) strains of S
...
HACO-MRSA
MRSE
Vancomycin
TOC: _________
_
VISA (vancomycin-intermediate Staphylococcus aureus)
VRSA (vancomycin-resistant Staphylococcus aureus)
Macrolide Resistance
• Resistance to clindamycin
• modified double disk diffusion test (D-zone test)
Title: Staphylococci
Description: All about Staphylococci and its related contents.
Description: All about Staphylococci and its related contents.