Staphylococcus Flashcards
Introduction:
- derived from gk term _____ which means ______
- Micrococcaceae family includes 2 genus
- discovered Staphylococcus and observed that the organisms appeared in clusters
- expanded the work of Ogston
- classified staph based on their _____ & _____
- staphle = bunches of grapes
- Staphylococcus & Micrococcus
- Alexander Ogston (1880)
- Friedrich Julius Rosenbach (1884)
- pigmentation & pathogenicity
General Characteristics
1. normal flora of ____ & _____
2. non______ and non_____
3. ______ or _______
- except ____ which is a obligate ______
4. BAP = characteristics:
- size
- color
- ____ looking
- s. aureus color
- s.epidermidis color
5. MSA grows at _____ (_____)
6. _______ = appears jet black colonies
7. considered as ____ bacteria due to presence of pus
- skin & mucous membrane
- nonmotile & nonsporeforming
- aerobic or facultative anaerobic
- S.saccharolyticus = obligate anaerobe - BAP
- medium
- cream-colored
- buttery-looking
- gray to yellowish
- gray to white - 7.5% Sodium Chloride (halophilic)
- Tellurite Glycine Agar
- pyogenic bacteria
STAPH AUREUS VIRULENCE
- heme enzyme
- hydrolyzes hydrogen peroxide into ____ & ____
- reagent for aerobic
- reagent for anaerobic - clots the plasma
- binds w/ ____ forming fibrin
- reagent - hydrolyzes hyaluronic acid which is important in invasion & survival
- aka
- present in the ______ that makes CT - breakdown of fibrin clots (fibrinolytic activity)
- CATALASE
- water & oxygen
- 15% hydrogen peroxide
- 3% hydrogen peroxide - COAGULASE
- fibrinogen
- rabbit plasma - HYALURONIDASE
- T-factor/ Spreading factor
- intracellular ground substance - STAPHYLOKINASE
STAPH AUREUS VIRULENCE
- dissolves lipids present on the surface of the skin, particularly fats & oil
- aka
- secreted by _____ - degrades DNA which lowers viscosity of exudate
- aka
- this is the reason why aureus becomes _____ - breaks down beta lactam drugs
- such as _____
- ____ coats the beta lactamase - acts as an anti-complement which binds Fc portion of IgG
- LIPASE
- FAT SPLITTING ENZYMW
- sebaceous glands - DNAse
- THERMONUCLEASE
- motile - BETA-LACTAMASE
- penicillin
- plasmin - PROTEIN A
STAPH AUREUS VIRULENCE
- causes various symptoms inc. diarrhea & vomiting which causes
- ________
- specific toxins that causes food poisoning (3)
- stable to heating at ____ for _____
- resistant to hydrolysis of ______ - targets and causes lysis to WBCs,; hence decrease fxn of phagocytosis
- causes severe _____ & ______
- associated w/ _________ - causes nearly all cases of menstruating-associated
- aka
- large amount of specific t-cells ________
- ENTEROTOXIN
- Heat-stable endotoxin
- ENTEROTOXIN A,B,D
- 100C for 30mins
- gastric juice - PANTON-VALENTINE LEUKOCIDIN
- cutaneous infection & necrotizing pneumoniae
- community acquired Staphylococcal infection - Toxic Shock Syndrome Toxin I
- Pyogenic Enterotoxin
- pro-inflammatory cytokines
STAPH AUREUS VIRULENCE
- targets RBCs and causes
- destroys RBCs, platelets, & macrophages
- causes injury to RBCs
- associated w/ Panton Valentine Leukocidin
- destroys sphingomyelin & RBCs around nerves (aka ____/______) - causes the epidermal layer of skin to slough off
- aka
- specifically known as ______
- known to cause _______ (aka)
- HEMOLYSIN
- ALPHA
- GAMMA
- DELTA
- BETA (aka hot-cold hemolysin/ sphingomyelinase C) - EXFOLIATIVE TOXIN
- Epidermolytic Toxin
- Exfoliative A&B superantigens
- Staphylococcal Scalded Skin Syndrome (Ritter’s Disease)
STAPH AUREUS INFECTIONS
- exfoliative dermatitis that occurs primarily in newborns & previously healthy young children
- aka - fatal multisystem disease
- progresses to ____ & ____ - rapid extensive heart valve damage
- skin & wound infections is surrounded by _____ & _____
- Scalded Skin Syndrome
- Ritter’s Disease - Toxic Shock Syndrome
- hypotension & shock - Acute Bacterial Endocarditis
- necrotic tissues & damaged leukocytes
Skin & Wound Infections (Cutaneous)
1. relatively mild inflammation of a hair follicle or oil gland
2. extension of folliculitis
3. larger, more invasive lesions
develop from multiple furuncles which penetrates deeper tissues
4. staphylococcal pustules that are large and surrounded by a small zone of erythema; contagious
- FOLLICULITIS
- FURUNCLES (BOIL)
- CARBUNCLES
- IMPETIGO
DIFFERENTIAL TESTS
1. Coagulase test
- ______ (slide method): positive result =
- _______ (tube method): positive result = _____ (incubation at ___ for ____)
2. Mannitol Fermentation Test
- components of MSA (2)
- pH indicator
- positive result: colonies surrounded by ______
3. test where it appears jet black colonies
- Coagulase test
- BOUND COAGULASE (Clumping Factor); clumping
- UNBOUND COAGULASE (Free Coagulase); clot formation (35-37C for 1-4hrs) - Mannitol Fermentation Test
- 1% mannitol + 7.5% NaCl
- phenol red
- colonies surrounded by yellow halos - Tellurite Glycine Agar Test
DIFFERENTIAL TESTS
1. resistant to polymyxins
- such as _____ & _____
2. utilizes glucose fermentation
- incorporation of _____ which is metabolize by bacteria
- reagents (2)
- positive result
3. based on ability to degrade/hydrolyzes DNA
- positive result
- Polymyxin Sensitivity Test
- polymyxin B & colistin - Voges-Proskauer Test
- 0.5% glucose
- alpha-naphthol & potassium hydroxide
- red/pink ring - DNAse test
- discoloration of methyl green color
________: carried by 2% of world’s population; spread thru contact or touching of skin
- resistant to _____ or ______
- types: (3)
- contains _____ gene
- coats the altered _______ which will make bacteria to not normally bind to oxacillin - identification:
- _____
- _____: presence of _______
- gold standard (aka)
Methicillin-Resistant Staphylococcus aureus (MRSA)
- nafcillin or oxacillin
- hospital associated MRSA; community associated MRSA; healthcare associated community onset MRSA
- mecA gene
- altered penicillin binding protein - identification:
- oxacillin salt-agar
- chromogenic agar; cefoxitin
- molecular nucleic acid probes ( PCR amplification)
