Staphylococci Flashcards
Give examples of Staphyloccoi species?
Staph. Aureus
Staph. Epidermidis
Staph. Saprophyticus
What shape is Staphylococci and how are they arranged?
Cocci/ round shape and arranged in clusters = looks like grapes
Gram stain? positive or negative?
Positive because of thick peptidoglycan in cell wall
Outline 3 special characteristic of Staphylococci
> capsule (slime)
> no spores
> flagella
What type of anaerobes are staphylococci and what does it mean?
Facultative anaerobes = can survive in aerobic and non-aerobic conditions
What are the conditions for staphylococci growth? Temp and pH?
37 degrees
7.2-7.4 pH
What culture medium is used for staphylococci?
Blood agar 5%
glucose broth
Is staphylococci highly resistant or low resistant?
Highly resistant
Outline non-toxigenic pathogenic factors of staphylococci ?
> coagulase and clumping factor > protein A > staphylokinase > DNA-ase > beta-lactamase > urease > catalase
Outline the toxigenic pathogenic factors of staphylococci?
> hemolysins - a, b, g > leucocydine > enterotoxins > exfoliatin > toxin of staphylococcus shock syndrome
How is staphylococci transmitted and how does it enter the body?
> via hands contact
aerosoles
blood
food
> enters through:
- mouth
- wounds
- vagina
- urethra
- skin and mucosa
Outline non-toxin mediated diseases of staphylococci aureus?
Non-toxin mediated diseases can be local or systemic:
>soft tissue infections: pyoderma, folliculitis, furuncles, carbuncles, abscesses
>pneumonia, endocarditis, osteomyelitis, sepsis
Outline toxin mediated diseases of staphylococci aureus?
These are toxigenic diseases: >food poisoning >toxic shock syndrome >toxic epidermal necrosis >staphylococcal scaled skin syndrome
What biological samples can be used for diagnosis of staphylococci aureus?
>pus >nasal swabs >blood culture >CSF >urine >feces
What type of direct method is used for Ag detection of staphylococci aureus?
> latex agglutination
> co- agglutination
Staphylococcus epidermidis is a normal flora of skin and mucosa but can cause other infections? State the infections it can cause?
> endoplastitis (catheter associated infection)
endocarditis (infection of artificial valves)
Peritonitis (peritoneal dialysis infection)
Staphylococcus Saprophyticus is a normal skin and mucosal flora but what other infection can it cause?
Cystitis in young women
What antibiotic treatment can be used against staphylococci?
> beta lactamase inhibitor
>cloxacillin and cephalosporins
Why are the antibiotic treatment with beta lactamase inhibitor and cloxacillin, cephalosporins ineffective with MRSA strains? How else can they be treated if with MRSA strain?
> because they produce beta lactamase with Mec-A gene
> MRSA infections treated with glycopeptides (vancomycin), linezolid and tigecycline