Staphylococcus spp One of the most common of all bacteria - - PowerPoint PPT Presentation
Staphylococcus spp One of the most common of all bacteria associated with humans and important pathogens Microbiology of Staphylococcus Gram + cocci generally in grape-like clusters (Gr, staphyle ) also singly, pairs, etc.
– generally in grape-like clusters (Gr, staphyle)
– Normal on skin, upper respiratory tract, vagina, intestines, etc.
– S. aureus
– S. epidermidis
– S. saprophyticus
– invasive “pus-formers”
– depending on virulence factors – major nosocomial disease agent
– hemolytic on blood agar
leukocytes, etc.
Zones of hemolysis due to different toxins
– Catalase
phagocytic lysis
– Coagulase
– Hyaluronidase
penetration
– DNAases – lipases – penicillinases – Protein A
– Cytotoxic toxins
WBC, tissue necrosis
– Toxic Shock Syndrome
– Exfoliative Toxin
bridges
– Enterotoxins
– 30-50% carriers – anterior nares & skin – endogenous infections – Impetigo is highly contagious
– health workers have high carrier rates
– hospitalized patients are often immuno- compromised – Neonatal infections – Serious problem of antibiotic resistant S. aureus (MDRSA) – surgery, catheterization etc.
– Furuncles (boils) – Carbuncles
cutaneously fevers, etc. far more serious
– Impetigo
also
– wound and burn infections Furuncle Carbuncle on neck
Stye, infected eyelash Carbuncle Impetigo Surgical wound infection Staph mastitis
– Exfoliatin, separation
dermal layers
– TSST-1 – fevers, rash, diarrhea marked desquamation
– S. aureus, # 1 – Enterotoxin (toxemia) – Highly heat resistant
salad, ham, etc.
Toxic Shock Syndrome Fatal TSS Fatal TSS
– skin flora – contaminate catheters, surgery, etc. – slime producers
– less pathogenic – common cause of UTI in young women
– also forms biofilms on prosthetics