Date post: | 17-Dec-2014 |
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Health & Medicine |
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بسم الله الرحمن الرحيم
GENUS:
STAPHYLOCOCCUSProf. Khalifa Sifaw Ghenghesh
1 2
STAPHYLOCOCCUS
Facultative Anaerobic, Gram +ve Cocci, Non-motile, Non-sporing, Arranged in Grape-like Clustures.
Catalase: 1. Coagulase Positive Staphylococci
(CPS) 2. Coagulase Negative Staphylococci
(CNS)
Scanning electron micrograph of Staphylococcus aureus
_________________________________Species Production of
Coagulase-------------------------------------------------------S. aureus +S. epidermidis --S. saprophyticus --_________________________________
Staphylococcus aureus
VIRULENCE FACTORS 1. Protein A:
> A Major Protien in the Cell Wall 2. Enterotoxins:
> Immunologic Types A-E. 3. - Toxin:
> Cytotoxic Effects: > Necrosis of Skin and Haemolysis.
Libya
2.5
27.5
20.07.52.5
40.0
0.0
A
B
C
AB
BC
Negative
4. Epidermolytic Toxins:> Impetigo and Scalded-Skin Syndrome.
5. Toxic-Shock Syndrome Toxin (TSST-1):
> Toxic Shock in Tampon Using Menstruating Women.
6. Enzymes:
i. Coagulase
ii. Fibrinolysin
iii. Hyaluronidase
iv. Lipase
CLINICAL INFECTION 1. Skin Infections:
> Impetigo, Furuncles, Cellulitis, Surgical and Wound Infections and Postpartum Breast Infections.
2. Bacteraemia:
>From Localized Lesions 3. Endocarditis: 4. Osteomyelitis: 5. Pneumonia: 6. Abscesses (metastatic):
> In any Organ
Sputum smear shows Staphylococcus aureus in a patient with staphylococcal pneumonia
7. Food Poisoning: 8. Toxic Shock Syndrome:
> Fever, Hypotension>> Multisystem
Involvement.
LAB. DIAGNOSIS: Specimens: i. Pus: From Abscesses, Wounds, Burns, Etc..
ii. Sputum:
iii. Faeces:
iv. Blood:
v. Mid-Stream Urine:
> Suspected Cystitis, Pyelonephritis or Post Catheterization Infection.
vi. Anterior Nasal and Perineal Swabs:
NA, BA, Milk Agar or MSA
Observe Colonial
Morphology
Gram Stain
Catalase Test
Slide or Tube Coagulase Test
PHAGE TYPING> For Epidemiological Studies.
TREATMENTi. Production of -Lactamase> Resistance to
Penicillins.
ii. Penicillins Stable to Staphylococcal Penicillinase:
> Methicillin, Cloxacillin and Flucloxacillin.
iii. Other Antibiotics:
iv. MRSA >>> Vancomycin.
EPIDEMIOLOGY:1. Sources of Infection:
i. Infected Lesions:> Doctors and Nurses.> Foodhandlers.
ii. Healthy Carriers:iii. Animals:
> Domesticated and Some Wild Animals:
2. Modes of Infection:– Exogenous– Endogenous
Cross Infections:> Important in Hospitals >> by Direct Contact.