Hello awesomites here is our first bacteria of micro-organism series - Staphylococcus aureus
Morphology:
Aerobes and facultative anaerobes
Diameter: 1 micrometer
Gram profile: Gram positive Cocci
Arrangement: Grape like clusters
Motility: Non-motile
Sporeing or not: Non-sporing
Capsule: Usually capsulated. Non-capsulated strains have small amount of capsular material on the surface
Aerobes and facultative anaerobes
Diameter: 1 micrometer
Gram profile: Gram positive Cocci
Arrangement: Grape like clusters
Motility: Non-motile
Sporeing or not: Non-sporing
Capsule: Usually capsulated. Non-capsulated strains have small amount of capsular material on the surface
Cultural characteristics:
Ordinary media: They grow readily with temperature range of 10-42°C ( Best at 37°C) and pH around 7.4 - 7.6
Nutrient agar:
You can remember how colony looks by the name STAPHYLOCOCCUS it self.
S - Smooth
O - Opaque
C - Circular
C - Convex
Easily emulsifiable.
It produces golden yellow pigment. Pigment production occurs best at 22℃ and only in aerobic culture. Growth represents "Oil-paint appearance".
Ordinary media: They grow readily with temperature range of 10-42°C ( Best at 37°C) and pH around 7.4 - 7.6
Nutrient agar:
You can remember how colony looks by the name STAPHYLOCOCCUS it self.
S - Smooth
O - Opaque
C - Circular
C - Convex
Easily emulsifiable.
It produces golden yellow pigment. Pigment production occurs best at 22℃ and only in aerobic culture. Growth represents "Oil-paint appearance".
Blood agar: Shows beta type of hemolysis when incubated under 20-25% carbon dioxide.
MacConkey agar: Pink colour small colonies (Because it ferments lactose!)
Selective media:
Ludlam's medium - Lithium chloride and tellurite.
Mannitol salt agar or salt milk agar- 1%Mannitol, 7.5%NaCl, Phenol red indicator.
Columbia colistin nalidixic acid agar.
Liquid media: Turbidity.
Biochemical Reactions:
Catalase : Positive
Oxidase : Negative
Mannitol: Positive
Indole: Negative
MR andVP: Positive
Phosphatase : Positive (Useful for screening as S epidermidis is negative or slightly positive )
Urease : Positive
Produces thermonuclease enzymes.
Oxidase : Negative
Mannitol: Positive
Indole: Negative
MR andVP: Positive
Phosphatase : Positive (Useful for screening as S epidermidis is negative or slightly positive )
Urease : Positive
Produces thermonuclease enzymes.
Virulence factors :
Extracellular enzymes :
Coagulase (Most virulent)
Lipase
Hyaluronidase
Staphylokinase
Toxins:
5 types of Cytolytic toxins: Alpha, Beta, Gamma, Delta and Leucocidins
Alpha: Most important hemolysin.
Beta: It is sphingomyelinase. Exhibits hot and cold phenomenon.
Leucocidin and gamma lysin is grouped under synergohymenotropic toxins.
9 types of enterotoxins: Responsible for staphylococcal food poisoning. Causes nausea, vomiting and diarrhoea within 2-6 hours.
A, B, C1, C2, C3, D, E, H and I.
Super antigens:
Alpha: Most important hemolysin.
Beta: It is sphingomyelinase. Exhibits hot and cold phenomenon.
Leucocidin and gamma lysin is grouped under synergohymenotropic toxins.
9 types of enterotoxins: Responsible for staphylococcal food poisoning. Causes nausea, vomiting and diarrhoea within 2-6 hours.
A, B, C1, C2, C3, D, E, H and I.
Super antigens:
Toxic shock syndrome toxin (TSST)
Exfoliative
Enterotoxins
(What are superantigens and how do they work?)
Exfoliative
Enterotoxins
(What are superantigens and how do they work?)
Disease caused:
Remember " SOFT PENIS"
S - Skin infections
O - Osteomyelitis and arthritis
F - Food poisoning
T - Toxic shock syndrome
P - Pharyngitis and Pneumonia (Rarely)
E - Endocarditis
N - Necrotizing fascitis
I - Impetigo
S - Sepsis
Remember " SOFT PENIS"
S - Skin infections
O - Osteomyelitis and arthritis
F - Food poisoning
T - Toxic shock syndrome
P - Pharyngitis and Pneumonia (Rarely)
E - Endocarditis
N - Necrotizing fascitis
I - Impetigo
S - Sepsis
Laboratory diagnosis:
Specimen and lesions
Pus - Suppurative lesions
Sputum - Respiratory Infections
Blood - Septicaemia
Urine - UTI
CSF- Meningitis
Faeces - Food poisoning
Sputum - Respiratory Infections
Blood - Septicaemia
Urine - UTI
CSF- Meningitis
Faeces - Food poisoning
Collection and transport :
Sterile containers should be used
Sterile swabs for specimen from nose/perineum.
Sterile containers should be used
Sterile swabs for specimen from nose/perineum.
Direct microscopy :
Gram stained smears is useful in case of pus, cocci in clusters may be seen.
Gram stained smears is useful in case of pus, cocci in clusters may be seen.
Treatment:
Sensitive to penicillin: Penicillin G is DOC (Drug of choice)
Penicillin allergy: Cefazolin is DOC
Methicillin resistant S.aureus: Vancomycin
Vancomycin resistant: S.aureus: Streptogramins, Linezolid, Telavancin.
That's all!
Finally done!
Stay awesome :)
~Khushboo shaikh,IkaN,and ojas
This is great! Thanks a lot. Can you please upload such notes for other bacterias too,please?
ReplyDeleteI will try. Thank you for appreciation
DeleteQuick way to revise ๐
ReplyDeleteGrt work๐
ReplyDelete