Staph Flashcards
Epidermidis characteristic
S. Saprophyticus
common laboratory contaminator
Commensal, skin and mucous membranes
genital tract in young women
Classification epidermis
Saprophyticus
Aerobic and facultative anaerobic Gram +ve, catalase +ve, coagulase –ve Sensitive to novobiocin Do not produce exotoxins
RResistant to novobiocin
Transmission epiderm
Saprophyticus
intravenous
ascend into the urinary bladder
Epidemi pathogenesis
Saprophyticus
- Polysaccharides (glycocalyx)
- Teichoic acid
Catalase
Diseases of epidem
Saprophyticus
[1] Infections of intravenous cannula or catheter
[2] Sub-acute bacteria endocarditis:
[3] Arthritis or osteomyelitis:
[4] Peritonitis:
[5] Skin Acne
[6] Stitch abscess
[7] Neonatal septicemia
Cystitis
فتشي خصائصهم
Pyelonephritis
Culture epider
Saprophyticus
Both. Blood agar: no hemolysis in blood agar, show white colonies
Treatment epiderm
Saprophyticus
- Removal of the catheter or other device is often necessary
- Vancomycin to which either rifampin or an aminoglycoside such as gentamicin can be added.
Ciprofloxacin
If contraindication for ciprofloxacin (e.g. pregnant women, child less than 8 years) we can give Trimethoprimsulfamethoxazol
S. Aureus Characteristics
Commensal in 30% , wet areas of skin
Non-fastidious منها مكسبها ومنها لا
Classification aureus
Aerobic and facultative anaerobic Coagulase +ve Catalase +ve Β-hemolytic Sensitive to novobiocin resist 7-10% NaCl (halophilic)
Culture aureus
- Blood agar
- MacConkey agar
- Mannitol salt agar
- 7 – 10 % NaCl
(pathogenicity) of s.aureus
➢
- Structure
Protein A, Teichoic acid, Peptidoglycan, Bound Coagulase,
(pathogenicity) of s,aureus
➢
- Exotoxins
Hemolysins, Leukocidins, Enterotoxin, (TSST-1, Exofoliatin, Epidemiologic toxin,
Enzymes of s.aureus
Catalase,coagulase 2type, β-lactamase, Hyaluronidase
The most important 2 suprantigenes are:
- Enterotoxins
- Toxic shock syndrome toxin (TSST-1)
pyogenic infections of s .aureus
اختصاراً للوقت شوفي الشيت
Toxin mediated infection of aureus
شوفي الشيت
Diagnosis of aureus
▪ Specimen collection: Depends on the site infected: Skin swab, nail, blood, sputum.
In TSS we take vaginal or nasal swab In food poisoning we take the specimen form the food
▪ Macroscopic examination: Pus from Staph. Aureus is creamy and sticky.
▪ Direct microscopy: Gram +ve cocci arrange in cluster
▪ Culturing: If the specimen is taken from sterile site (i.e. No commensals we use blood agar or mannitol salt agar.
If taken from non-sterile site, we use (7-10 % NaCl)
▪ Biochemical test: Catalase +ve Coagulase +ve DNase (most likely +ve, in some case -ve)
▪ In- vitro sensitivity test: Using novobiocin, we differentiate between s. epidermidis and Aureus (sensitive) s. Saprophyticus (resistant)
Treatment of aureus
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