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.