seminario biologia molecular
TRANSCRIPT
Molecular epidemiology and characterization of virulence genes of
commnunity-acquired and hospital-acquiredmethicillin-resistant Staphylococcus aureus
in Colombia
Bibiana Chavarro Portillo, Jaime Enrique Moreno, Nancy Yomayusa, Carlos Arturo Álvarez, Betsy Esperanza Castro Cardozo, Javier Antonio Escobar
Pérez, Paula Lucía Díaz, Milciades Ibañez, Sebastián Mendez-Alvarez, Aura Lucía Leal, Natasha Vanegas Gómez
Manuela Rendón DíezDaniel Peña Tobón
Methicillin-resistant Staphylococcus aureus
Kind Virulence Factors
Staphylococcus
Strucutaralcomponents
Enzymes
Toxins
Genus Methicillin
Aureus Beta Lactamantiobiotic
INTRODUCTION
INTRODUCTION
Stap
hyl
oco
ccu
sFrom the Greck sthapylé meaning bunch of grapes
Gram Positive Bacteria
Facultative bacteria growth: growing in aerobic and anaerobic enviroments
Microorganims in the skin and mucous of humans and animals
Cell wall: pollysaccharide capsule to protect fromphagocytosis
Secreat liquid with monosaccharides, proteins and peptides: to increase their bond sterenght
Au
reu
sFacultative anaerobic bacteria
Gram Positive Bacteria
Produce diseases like
Main cause of nosocomial infections: passingeasily into the bloodstream
Pollysaccharide cell envelope: increase adhesioncapacity, prevents recognition, reinforces it´santiphagocytic effect
INTRODUCTION
Benign skin infections: folliculitis
Benign mucosalinfections: conjunctivitis
Life threateningdiseases: ostomyelitis, meningitis, sepsis, pneumonia
INTRODUCTION
Methicillin
Beta-lactamantiobiotic
Was used totreat
infections
Caused bygram positive
bacteria
That produce beta-
lactamase
INTRODUCTION
Methicillin
MODE OF
ACTION
Inhibiting the synthesis of bacterial
cell walls
Inhibitioncompetitive of transpeptidase
enzyme
Prevents formation of
bonds between the
peptidoglycan chains
INTRODUCTION
Virulence factors
Structural components
Virulence factors Action
Capsule Inhibits chemotaxis and phagocytosis
Extracelular pollysaccharides
Facilites adhesion
Peptidoglycan Stimulates cell lysis and production of endogenous pyrogens
Teichoic acid Staphylococcus adhesion to fibronectin
MSCRAMM Increase tissue adhesion
Protein A Inmune response decreases
INTRODUCTION
Virulence factors
Enzymes
Virulence factors Action
Coagulase Transformation of fibrinogen to fibrin (inmune response decreases)
Hyaluronidase Destruction of hialuronic acid to the spread of s.aureus
Fibrinolysin Dissolves fibrin clots
Lipases Lipid hydrolisis: acumulation of s.aureus
Endonucleases/DNAsa DNA hydrolysis
Beta lactamases
INTRODUCTION
Virulence factors
Toxins
Virulence factors Action
Cytotoxins Destroys cells
Exfoliative toxins Cutaneous damages
Enterotoxins Gastrointestinal problems by openin channels
TSST-1 Toxic shock: lymphocyte activation for citokine production
Methicillin-resistant Staphylococcus aureus (MRSA)
Infection that doesnt improve with the first line of antibiotics
Acquired in the hospital or in the community
HAChilean clone
Brazilian clone
CA USA 300
Virulence factors: severity of infectionsProteolytic activity, toxic and litic effects
Frequent in patients with weakenedinmune systems
INTRODUCTION
Methicillin-resistant Staphylococcus aureus (MRSA)
INTRODUCTION
Symptoms and sings
Skin: red, swollenand sore
Secretionof pus
Woundsthat dont
heal
Chestpain
Cough
Shortnessof breath
Fatigue
OBJECTIVE
To determine the molecular epidemilogy and presence of virulence genes in community-acquired (CA) and hospital-acquired (HA) methicillin-resistant Staphylococus aureus
(MRSA) insolates and their relationship to clinical outcomes.
MATERIALES Y MÉTODOS
Población de estudio
Junio 2006-Diciembre 2007
Mayores de 18 años
Hospitales de 3° nivel
Muestras clínicas
Enviadas a la laboratorio de referencia
Datos clínicos
Infección
Resultado
Recaída
Mejora
Muerte
30 días
Sangre
Secreciones
Tejidos blandos
Heridas
Aislados bacterianos y cepas de referencia
Mu50
TC146
USA 300-0114
JCSC4744
JCSC2172
81/108
JCSC4469
NPS123
USA500
FRI1151
MATERIALES Y MÉTODOS
MATERIALES Y MÉTODOS
PRC: Reacción en cadena de polimerasa
*Kary Mullis --- > 80´s
*Amplificación directa de un gen o un fragmento de DNA*Incremento en el número de copias de un DNA en corto tiempo
MATERIALES Y MÉTODOS
PRC: ¿Qué necesito?
*DNA plantilla*Primer*DNA polimerasa*Buffer
PRC: ¿Para qué?
*Clonación*Establecer polimorfirmos*Dx enfermedades genéticas*Medicina Forense*Detección de microorganismos infecciosos
PRC y el staphylococcus aureus resistente a la meticilina???
MATERIALES Y MÉTODOS
Confirmar especie y resistencia a meticilina.
*Enterotoxina*Exfoliativa*Hemolisina*Shock Tóxico*Protíenas adhesivas
Presencia de
MATERIALES Y MÉTODOS
PFGE: Electroforesis en gel de campo pulsátil
ELECTROFORESISUtilización de corriente eléctrica
controlada
Separación de biomoléculas según:
Carga Tamaño
MATERIALES Y MÉTODOS
PFGE: Electroforesis en gel de campo pulsátil
*Reducción del movimiento de las moléculas utilizando un medio que oponga resistencia =GEL
Los fragmentos son sometidos a cargas eléctricas en diferentes direcciones.
MATERIALES Y MÉTODOS
PFGE: Electroforesis en gel de campo pulsátil
*Separación de grandes fragmentos de DNA
Induce reordenamiento por cambios eléctricos periódicos constantes
Duración en el campo eléctrico determina el tamaño del fragmento.
MATERIALES Y MÉTODOS
Susceptibilidad antimicrobiana Métodos para determinar la susceptibilidad de los organismos a
agentes antimicrobianos.
*Oxacilina*Gentamicina*Rifampicina*Eritromicina*Ciprofloxacina*Vancomicina*Linezoild*Tetraciclina*Clindamicina*Trimetropim*Sulfametoxazol
MATERIALES Y MÉTODOS
Susceptibilidad antimicrobiana
Recomendaciones para establecer la terapia mas
adecuada para un paciente
Se obtuvieron diferentes patrones de los 270
aislados
• F, U, D, G, H, K,O y P
Por PFGE buscando relación genética con
• Clon Chileno, Clon USA300-0114, Clon pediátrico
RESULTADOS
• 162 (60 %)
• Clon Chileno -relación genética (>78,8%)
PATRÓN F
• 86(31,8%)
• USA300-0114 –relación genética (>79%)
PATRÓN U
• 4(1,5%)
• Clon pediátrico–relación genética (79%)
PATRÓN D
RESULTADOS
• ST1110 - 2 aislamientos
Clon Chileno – gen arcC
• ST1111 – 1 aislamiento
Clon Pediátrico – gen arcC
ANÁLISIS POR MLST
RESULTADOS
RESULTADOS
TIPIFICACION POR SCCmec
Patrón U
82 – Tipo IVc / 3 – Tipo IVa / 1 – Tipo IVb
Patrones F y D
Tipo I y IV
Patrón G
9 – Tipo II
1- Tipo I
RESULTADOS
Factores de Virulencia
• Genes sem, sen y seo (184), seg (173), sei (154) ------- Grupo de genes de la enterotoxina ( EGC )
• Toxina exfoliativa A (52 CA-MRSA y 171 HA-MSRA)
• Toxina exfoliativa B (4)
• Genes sej and seg (2 HA-MRSA)
• Genes sek, seq y lukF-PV/luckS-PS (CA –MRSA)
• Proteínas de unión a fibronectina A y B (CA-MRSA)
RESULTADOS
MORTALIDAD • Relación entre la mortalidad y lainfección por HA – MRSA encomparación con CA-MRSA ( 21 vs10,6 %)
• Aumento en mortalidad en pacientescon bacteriemia (45,9%), neumonía (43,8%), en comparación con infecciónen el sitio quirúrgico (10,8%)
• Existen relación directos entrefactores de virulencia y patologíasdesarrolladas
DISCUSSION
INVESTIGATORS IDEA AGREE OR DISAGREE
Ferry T, Thomas D, Genestier AL, Bes M, et al.
Described a greaterprevalence of the egc –positive isolates recoveredfrom surfaces infectionscompared to invasiveinfections.
Ferry T, Thomas D, Genestier AL, Bes M, et al
Observed a negativerelationship between theegc cluster and clinicalseverity
DISCUSSION
INVESTIGATORS IDEA AGREE OR DISAGREE
Van Belkun A, Melles DC, Snijders SV et al
They did not find anyevidence of an associationof the egc cluster withmortlity in patients withMRSA- related bacteremia.
Bae IG, Tonthat GT, Stryjewsky ME et al
They found a paradoxicallyhigther rate of clinicalhealing through thepresence of some adhesivegenes
CONCLUSIONS
*Staphylococcus aureus is a microorganismthat causes problems in hospitals, becausewhen people go to the hospital for manysurgeries can be infected with the organism
*The high quantity of isolates of MRSA are a major problem for atreatment, this microorganism is difficult to eradicate because when wewant kill the pathogen agent, we found that each clones of MRSA has aimportant number of isolates with genomic differences between its.
CONCLUSIONS
*The types of MRSA ( USA300-0114, pediatric yChilean ) has many genes that generate thedifferent between its, that to permite separatethe isolates in families. The genetic variabilityis essential as a survival mechanism of theorganism.
*This article is very important because the investigators developed astudy for explain the molecular and genetic causes in Staphylococcusaureus infection, based in identify the genetic variability, then whenthey identified the genes that generate differences between clones, theinvestigators found the relationship between genes and diseases