3. INTRODUCTION
Staphylococcus:
• Bacteria Gram-positive cocci formed in grape-like clusters.
• Facultative anaerobes.
• Resistant to hostile conditions.
• Rapid development.
• Ferments carbohydrates and produce pigments (white
• to yellow).
• Catalase positive.
• At least 40 species S. epidermidis, S. saprophyticus, S.
aureus.
• Commensal nostrils, skin and mucous membranes.
4. INTRODUCTION
S. aureus:
• "Golden staph" or Oro staphira.
• Stationary and non-spore.
• Capsule slime or mucoid (polysaccharid).
• Coagulase positive.
• Pathogen polymorphic mucocutaneous infections, shock toxic syndromes,
toxic food-borne infections, nosocomial infections.
5. INTRODUCTION
Product Effect
Capsule Inhibits phagocytosis
Coagulase May prevent the progression of
leukocytes in the infected area produce
clots in neighboring capillaries
Exfoliatin Separates the layers of the epidermis,
causing Scalded skin Syndrome
Hyaluronidase Decomposes hyaluronic acid of
tissues and promotes spread of
infection
Leukocidin Destroys leukocytes producing holes in
the cytoplasmic membrane
Lipase Descomposes fats hydrolyzing the
bond between glycerol and fatty acids
Proteases Degrades collagen and other tissue
proteins
6. INTRODUCTION
Product Effect
A Protein Binds to the Fc portion of the antibody
inhibiting phagocytosis
Septic shock
Syndrome Toxin
Causes rash, diarrhea and shock
Clumping factor Binds bacteria to fibrin, fibrinogen and
plastic elements
Fibronectin
binding protein
Binds bacteria to the acellular tissue
substance, epithelium, endothelium, blood
clots, plastic elements to stay.
α, β, γ and δ toxins Dermonecrotic effect
Leukocidin Destroys neutrophils or cause release of
their enzymes
Enterotoxins Superantigens. Cause food poisoning if
they are ingested
TSST-1 Superantigen. If they are systemic causes
toxic shock
9. MÉTODOS
Aislamiento de bacterias :
• Funda
Prueba Fundamento Objetivo Imagen
Catalasa Descomposición del
peróxido de hidrógeno
Distinguir de especies de
Streptococcus,
Enterococcus y
Lactococcus.
Coagulasa Reacciona con
protrombina fibrinógeno
se convierte en fibrina
Diferenciar de
Staphylococcus
coagulasa- negativa
MSA Alta concentración
de NaCl, manitol y rojo de
fenol (pH)
Identificar
Staphylococcus
coagulasa-positivos
Test
Dnasa
Agar
Detección de enzimas
desoxirribonucleasas.
Diferenciación entre
especies de
Staphylococcus
10. MÉTODOS
Prueba de susceptibilidad antibiótica
• AST Método de Kirby Bauer.
• Fundamento determina la sensibilidad de
un agente microbiano frente a un antibiótico
o quimioterápico.
• Antibiograma o prueba de susceptibilidad
bacteriana frente a drogas específicas.
• Objetivo determinar a cuál de los
antibióticos es resistente la bacteria.
• Sensible (S), Intermedio o Moderadamente
sensible (I) y Resistente (R).
11. MÉTODOS
Extracción de DNA genómico
1. Lisis de bacterias Gram-positivas lisostafina.
2. Degradación del RNA opcional.
3. Precipitación de proteínas ácido acético.
4. Precipitación de DNA isopropanol.
5. Almacenamiento en TE buffer ácido etilendiaminotetraacético (EDTA).
6. Marcación con FISH hibridación fluorescente in situ.
12. MÉTODOS
PCR
• Obtención de muchas copias de una fragmento de DNA particular
amplificación de un fragmento de DNA.
• Fundamento propiedad natural de los ADN polimerasas para replicar
hebras de ADN ciclos de altas y bajas temperaturas alternadas
separar hebras de ADN recién formadas dejar que las hebras de ADN
vuelvan a unirse para poder duplicarlas nuevamente.
• Sensibilidad, Especificidad, Eficiencia,
Fidelidad.
• Desnaturalización, alineamiento,
extensión, elongación final, conservación.
16. Author Conclusion Yes or not
Shittu All of the isolates were susceptible to vancomycin and
linezolid.
YES
Sharma All clinical isolates were susceptible to vancomycin YES
Japoni 74.3% of isolates in south of Iran were SCCmec type
III
YES
Ho 91.6% of clinical isolates belonged to arg group I YES
DISCUSSION
17. • Staphylococcus aureus has particular ways of
manifestations and resistances that could complicate a
infection´s treatment.
• Strain type is determinant in the expression of resistant
genes that are a challenge when a treatment will be
developed.
CONCLUSIONS
18. • Although there are two antibiotics which can treat the
infection by S. aureus could cause a resistance because
of chronic use.
• The knowledge of the kind of Strain that cause the
infection is important to guide a treatment plan, avoiding
the use of ineffective antibiotics.
CONCLUSIONS
