02 GRAM POSITIVE COCCI (Staph & Micrococcus) Flashcards
Tell whether positive or negative
Catalase result for Staphylococcus
Positive
Tell whether positive or negative
Catalase result for Micrococcus
Positive
Tell whether positive or negative
Anaerobic growth for Staphylococcus
Positive
Tell whether positive or negative
Anaerobic growth for Micrococcus
Negative
Glucose utilization of Staphylococcus
Fermentative
Glucose utilization of Micrococcus
Oxidative/ Nonsaccharolytic
Tell whether positive or negative
Modified oxidase test for Staphylococcus
Negative
Tell whether positive or negative
Modified oxidase test for Micrococcus
Positive
Tell whether positive or negative
Benzidine test for Staphylococcus
Negative
Tell whether positive or negative
Benzidine test for Micrococcus
Positive
Tell whether positive or negative
Production of acid from glycerol in the presence of erythromycin for Staphylococcus
Positive
Tell whether positive or negative
Production of acid from glycerol in the presence of erythromycin for Micrococcus
Negative
Tell whether positive or negative
Growth on Furoxone-Tween 80 oil red O agar for Staphylococcus
Negative
Tell whether positive or negative
Growth on Furozone-Tween 80 oil red O agar for Micrococcus
Positive
Tell whether susceptible or resistant
Lysostaphin for Staphylococcus
Susceptible
Tell whether susceptible or resistant
Lysostaphin for Micrococcus
Resistant
Tell whether susceptible or resistant
Bacitracin for Staphylococcus
Resistant
Tell whether susceptible or resistant
Bacitracin for Micrococcus
Susceptible
more than or equal to 10mm ZOI
Tell whether susceptible or resistant
Furazolidone for Staphylococcus
Susceptible
more than or equal to 15 mm
Tell whether susceptible or resistant
Furazolidone for Micrococcus
Resistant
Micrococci belong to the family ___
Micrococcaceae
Usually normal flora and associated with skin lesions and more commonly isolated among immunocompromised patients
Micrococci
Micrococci may be found in the ___
Environment
Other gram positive cocci that may be mistaken for Staphylococcus
- *Rothia mucilaginosa/ Stomatococcus mucilanginosus
- Aerococcus
- Alloiococcus otitis*
Other gram positive cocci that may be mistaken for Staphylococcus
Gr (+) encapsulated cocci
Rothia mucilaginosa/ Stomatococcus mucilanginosus
Other gram positive cocci that may be mistaken for Staphylococcus
Emerging pathogen causing UTI and endocarditis
Rothia mucilaginosa/ Stomatococcus mucilanginosus
Rothia mucilaginosa/ Stomatococcus mucilanginosus
Often from airdust and hospital environment
Aerococcus
they are also catalase (+)
Rothia mucilaginosa/ Stomatococcus mucilanginosus
First isolated in the ear
Alloiococcus otitis
Staphylococci belong to family ___
Staphylococcaceae
Staphylococci are Gr (+) cocci that are usually ____ in size
0.5-1.5 um
All Staphylococci are catalase positive except ___
S. aureus subsp. anaerobius and S. saccharolyticus
All Staphylococcis are modified oxidase negative except ___
S. sciuri, S. lentus, S. vitulus
The positive result for modified oxidase test is ___
Blue-purple coloration
T/F
All Staphylococci are non-motile and non-sporeformers
T
All Staphylococci are aerobic or facultative anaerobe except ___
Staphylococcus aureus subsp. anaerobius, Staphylococcus saccharolyticus
Colonial morphology
Staphylococci:
S. albus
Buttery-looking, white colony
Colonial morphology
*Staphylococci:
S. aureus*
Golden yellow
due to Staphyloxanthin
Colonial morphology
*Staphylococci:
S. citrus*
Lemon yellow
more seen in Loeffler’s serum slant
General morphology of Staphylococci colonies
- Pinhead/ Medium sized
- Raised
- Creamy
- Lemon yellow or golden yellow
Most clinically significant Staphylococci
S. aureus
Other coagulase producing Staphylococci
- S. intermedius
- S. pseudointermedius
- S. hyicus
- S. delphini
- S. lutrae
- S. agnetis
- some strains of S. schleiferi
Novobiocin susceptible CONS
CONS = Coagulase negative Staphylococci
S. epidermidis, S. haemolyticus
Novobiocin resistant CONS
CONS = Coagulase negative Staphylococci
S. saprophyticus, S. xylosus
Primary reservoir of S. aureus in humans
Human nares
Coagulase negative Staphylococci
- S. epidermidis
- S. lugdunensis
- S. saprophyticus
Staphylococcus spp.
Causes a wide variety of diseases such as pimples, sty, cellulitis, folliculities, toxic shock syndrome, scalded skin syndrome, food poisoning, impetifo, furnucles, and carbuncles
S. aureus
Staphylococcus spp.
Can be recovered from almost any clinical specimen
S. aureus
Staphylococcus spp.
Also an important cause of nosocomial and opportunistic infections
S. aureus
S. aureus virulence factor
Trigger exaggerated immune response
TSS-1; superantigens
S. aureus virulence factor
Associated with the smooth muscle of blood vessels
Alpha hemolysin
S. aureus virulence factor
Heat-labile, “hot-cold” lysin
Beta hemolysin
“sphingomyelin”
S. aureus virulence factor
Hemolysin associated with Panton Valentine Factor
Gamma hemolysin
S. aureus virulence factor
Prevents B-lactam action; present in MRSA
PBP2
S. aureus virulence factor
Hydrolyzed by staphylcoagulase in the intracellular ground substance
Hyaluronidase
S. aureus virulence factor
Act on lipid present on the sebaceous glands
Lipase
S. aureus virulence factor
Lyse fibrinogen; cell-bound
Staphycoagulase
“free coagulase”; that’s why it is slide coagulase (+)
S. aureus virulence factor
Causes scalded skin syndrome
Exfoliative toxin
S. aureus virulence factor
Cell wall component that prevent opsonization
Protein A
Antiphagocytic
S. aureus virulence factor
Activate complement (IL1)
endotoxin
Teichoic acid
S. aureus virulence factor
Chemotactic factor for PMN
Teichoic acid
recruit PMN to go into infection = puss formation
S. aureus virulence factor
Capable of destroying tissues and responsible for spread of infection
- DNAse
- Lipase
- Hyaluronidase
- Staphylokinase
S. aureus virulence factor
Causes diarrhea & vomitting
Enterotoxins
heat-stable toxins
S. aureus virulence factor
Staphylococcal food poisoning
Enterotoxin A, B, D
S. aureus virulence factor
Linked with pseudomembranous enterocolitis
Enterotoxin B
S. aureus virulence factor
Causes almost all cases of menstruating TSS
TSS = toxic shock syndrome
TSST-1
S. aureus virulence factor
Absorbed through vaginal mucosse
TSST-1
S. aureus virulence factor
Chromosomal-mediated toxin; stimulates T-cell proliferation & symptoms
TSST-1
S. aureus virulence factor
TSST-1 is previously called ___
Enterotoxin F
S. aureus virulence factor
Exfoliative toxin is also known as ___
Epidermolytic toxin
S. aureus virulence factor
Implicated in Ritter-Lyell disease
Ritter-Lyell disease = scalded skin or dermatitis exfoliativa
Exfoliative toxin
S. aureus virulence factor
Implicated in Bullous impetigo
Exfoliative toxin
S. aureus virulence factor
Extracellular toxins that affect RBCs and WBCs
Cytolytic toxins
S. aureus virulence factor
WBC destruction; antiphagocytic
Leukocidin
associated w/ PVF
S. aureus virulence factor
Localization of abscess
Staphylocoagulase
virulence marker; used for diagnosis
S. aureus virulence factor
Beta hemolysin is associated with enhanced hemolytic activity at __ C incubation
37C
S. aureus virulence factor
Associated with invasiveness of organism by suppressing phagocytosis and has rotizing pneumonia
Panton-Valentine factor
under gamma hemolysin
S. aureus virulence factor
Less toxic hemolysin
Delta hemolysin
S. aureus-associated infection
Occurs among newborns and previously healthy young children; also seen among adults with chronic renal failure
Scalded skin syndrome (SSS)
S. aureus-associated infection
A multisystemic disease that is rare, but is potentially fatal
Toxic shock syndrome
S. aureus-associated infection
Has multiple causes; may be due to a hypersensitivity reaction; very similar initial presentation to that of SSS
Toxic epidermal necrolysis
S. aureus-associated infection
Gastrointestinal disturbances
Staphylococcal food poisoning
S. aureus-associated infection
Staphylococcal food poisoning has an incubation period of ___
2-8 hrs
Most common enterotoxin causing food poisoning
Enterotoxin A
Other infection cause by S. aureus
Increased WBC; presence of organism in synovial fluid
Septic arthritis
may also be caused by N. gonorrhoeae
S. aureus-associated infection
Most common
Osteomyelitis
CONS
50% of CONS isolates
S. epidermidis
CONS
Most common cause of prosthetic valve endocarditis
S. epidermidis
Also causes “stitch abscess”
CONS
Common cause of nosocomial UTIs
S. epidermidis
CONS
Usually a normal inhabitant of the skin
S. epidermidis
CONS
A common blood culture contaminant and may colonize medical devices
S. epidermidis
CONS
2nd most common cause of UTIs
S. saprophyticus
CONS
Associated with pyelonephritis and cystitis in young women and in older men using catheters
S. saprophyticus
Staphylococcus spp.
A cause of nosocomial infections such as aggressive endocarditis, septicemia, meningitis, and skin and soft tissue infections
S. lugdunensis
Staphylococcus spp.
Has a high mortality rate due to aggressive endocarditis
S. lugdunensis
Staphylococcus spp.
S. ludgunensis is slide coagulase (_)
Positive
positive for clumping factor
Other Staphylococci
Present in dogs
S. intermedius
Other Staphylococci
Present in dolphins
S. delphini
Laboratory dx. of Staphylococcus spp.
Preferred sample
Aspirate
if there is an inflammation
Laboratory dx. of Staphylococcus spp.; culture media
Selective for Gr (+) cocci
Columbia Colistin Nalidixic Agar
Laboratory dx. of Staphylococcus spp.; culture media
Selective and differential for Staphylococcus spp. based on mannitol fermentation
Mannitol Salt Agar (MSA)
Laboratory dx. of Staphylococcus spp.; culture media
Positive result for CHROMagar for S. aureus identification
mauve/ pink coloration
Identify the Staphylococcus spp.;
Beta-hemolytic; pinhead colonies and greenish discoloration in CAP
S. aureus
Identify the Staphylococcus spp.;
Small-medium sized, gray colonies; non-hemolytic
S. epidermidis
Identify the Staphylococcus spp.;
Medium sized colonies; beta-hemolytic
S. lugdunensis
Identify the Staphylococcus spp.;
Mannitol fermenter
S. aureus
yellow coloration on MSA
Identify the Staphylococcus spp.;
Non-mannitol fermenter
S. epidermidis
no color change in MSA; pink
Laboratory dx. of Staphylococcus spp.
Reagent of catalase test
3% H2O2
Laboratory dx. of Staphylococcus spp.
Reagent of modified oxidase test
6% tetramethylphenylenediamine HCl in DMSO
Laboratory dx. of Staphylococcus spp.
Positive result for modified oxidase test
Dark blue
Laboratory dx. of Staphylococcus spp.
Colonies from __ causes false positive result in catalase test
BAP
Laboratory dx. of Staphylococcus spp.
Causes false positive in modified oxidase test
The use of nichrome/ iron loops
Laboratory dx. of Staphylococcus spp.
Reagen of coagulase test
Rabbit plasma
Laboratory dx. of Staphylococcus spp.
In coagulase test, the clot can be dissolved by ___
Staphylokinase
“staphylococcal fibrinolysin/ Muller’s factor”
Laboratory dx. of Staphylococcus spp.
Differentiates organisms based on the ability to oxidize of ferment sugars
Oxidation fermentation test
Laboratory dx. of Staphylococcus spp.
Reagent of DNAse test
Toluidine blue or Methyl green
Laboratory dx. of Staphylococcus spp.
Positive result for DNAse test
Hydrolysis of surrounding medium
clear zone
Laboratory dx. of Staphylococcus spp.
Tests for the formation of acetoin from glucose
through Butylene Glycol pathway
Voges Proskauer test
Laboratory dx. of Staphylococcus spp.
Differentiates coagulase (+) Staphylococcus
- Voges Proskauer test
- PYR test
Laboratory dx. of Staphylococcus spp.
Positive result for Voges Proskauer test
Red coloration in MRVP broth
Laboratory dx. of Staphylococcus spp.
Positive result for PYR test
Pink or cherry-red coloration
Laboratory dx. of Staphylococcus spp.
Useful test to differentiate CONS
Novobiocin
S. aureus (S); S. saprophyticus (R)
Laboratory dx. of Staphylococcus spp.
Most useful for confirming S. lugdunensis
Ornithine decarboxylase test
(+): Violate coloration on ODC tube
Laboratory dx. of Staphylococcus spp.
Gold standard for MRSA detection
detection of mecA gene
Laboratory dx. of Staphylococcus spp.
Recommended screening test for MRSA
Cefoxitin test
30 ug; less than or equal to 21 mm (R)
Laboratory dx. of Staphylococcus spp.
The MRSA screen agar uses ___ with ___ NaCl
oxacillin
2-4%
growth indicates Methicillin resistance
DOC for VRSA
Linezolid
Laboratory dx. of Staphylococcus spp.
Macrolide resistance is detected through what method?
D-zone test
erythromycin & clindamyzin 15 mm apart
Identify the Staphylococcus spp.
Slide coagulase (+)
Tube coagulase (-)
ODC (+)
S. lugdunensis
Identify the Staphylococcus spp.
Slide coagulase (+)
Tube coagulase (-)
ODC (-)
S. hyicus
Identify the Staphylococcus spp.
Novobiocin (R)
Polymyxin B (S)
S. saprophyticus
Identify the Staphylococcus spp.
Novobiocin (S)
Polymyxin B (R)
S. epidermidis
Identify the Staphylococcus spp.
Novobiocin (S)
Polymyxin B (S)
S. haemolyticus