Medically important cocci

Pyogenic bacteria

• Staphylococcus (family Micrococcaceae)

• Streptococcus (family Streptococcaceae)

• Neisseria (family Neisseriaceae)

Staphylococci

• Skin and mucous membrane

• Pathogen for human and animals

• Gram positive cocci

• Facultative aero-anaerobi

• Appearing in clusters, short chains anddiplococci

• Lack flagella and spore

• Some contains capsule

StaphylococciI. Generals: 30 species

– S.saprophyticus

– S.epidermidis( S.slbus)

= Staphylococcus aureus

Staphylococcus aureus

• Spherical 1µ

• In clusters after cultivation on solid media

cultivation

• 37 0C ( 10-46 0C )

• Aero-anaerobic ( O2 and CO2)

• NaCl (7.5-10%)

• Heat (600C to 1h)

• Antibiotics and antiseptics

Enzymes of S.aureus

• Coagulase (97%)

• Hyaluronidase (spreading factor)

• Fibrinolysine (35%)

• DNAase

• Lipase

• Catalase

• Penicillinase (more than 75%)

Toxins of S.aureus

• Hemolysins (α- Hemolysine , β hemolysine, δ hemolysine , γ hemolysine )

• Leukucidin

• Enterotoxin (A-F) 50%S.aureus (resist to boiling for 30min)

• Exfoliative toxin (SSSS)

• TSST

Pathogenicity

A. Staphylococcus aureus

A.1 Localized infections

– Cutaneous (folliculitis, furuncle, impetigo,carbuncle,blepharitis, panaris)

– ORL (sinusite, otitis, Pneumonia)

– Septicemia ,osteomyelitis,endocarditis,polyarthritis,meningitis, toxemia

A.2 Toxic infections

– Toxic shock syndrom– SSSS(staphylococcal scalded skin syndrom)– Food intoxication (1-8h) vomiting ,diarrhea, nausea, self limited

Site of pathogenicity

abcès

folliculitis

furuncle

Abcess

folliculitis

Osteomyelitis

Chronic osteomyelitis

STAPHYLOCOCCICTOXINFECTIONS

I. STAPHYLOCOCCAL SCALDED SKIN SYNDROME

– (SSSS)– : S. aureus produce exfoliative toxin– Fever– Generalised eruptions (cutaneous + mucous)

Scarlatine staphylococcique

Toxic shock

Impétigo bulleux

SSSS

Impétigo

Non supurative infetions of toxic origin

SSSS

Impétigo bulleux

EXFOLIATINE

Staphylococcus aureusPathogenicity

SSSS

STAPHYLOCOCCIC TOXEMIA

• III - Staphylococcal toxic shock syndrom

– 5-10 % mortality

– TSST-1

– 20-30 % portal of entry vaginal

– Character hyper-absorbant to certain tampons.

staphylococcal toxic shock

– Staphylococcal toxic shock syndrome

• High fever

• hypotension

• Profound cutaneous nodules

• Myalgia

• Cardiac and tubular complications

• S.aureus TSST1

B. Other staphylococci( coagulase negative

Staphylococcus epidermidis, S.saprophyticus S. capitis …..Opportunistic and nosocomial ( immunocompromised patients)

S.epidermidis: skin, hair follicules and mucous membrane (UTI,Endocardits, Bacteremia)

S.saprophyticus: skin, intestine and vagina( esp UTI)

Mode of transmission:-surgery-catheter-Instruments_truama

Direct biologic diagnosis

– Gram staining

– Gram positive cocci

Catalase + (differentiate from strept)

Direct biologic diagnosis

Identification Aspect of colonies Coagulase

S. aureus golden Positive

S. albus white Négative

S.Saprophyticus Variable

– ANTIBIOGRAMME

Color of colonies Golden white Vulnerable

Anaerobic + - -

Aerobic + w w

Manitol fermentation + - w*

sensitive to lysostaphin + - -

sensitive to novobiocin + + -

β- hemolysis(α-toxin) + - -

Coagulase+ - -

Test S.aures S. epdermidis S.saprophyticus

تجرید انواع استافیلوکوک ھای عمده ازنگاه کلینیکی

* Weak

Treatment

• Multidrug resistant

• Penicilline, Gentamicine, Tetracycline, Methicilin,Quinolones, Erythromycine, Sulfamides, Cephalosporines, Rifampicin

Epidemiology

• Main reservoir are human and abcess

• Careful hygiene and adequate cleansing of surgical incisions and burns

• Isolation of people with open lesions

• Handwashing, proper disposal of infectious dressings and discharges.