Seminario biolo molecular

Methicillin-resistant Staphylococcus aureus ST30-SCCmec IVc clone as the major

cause of community-acquired invasive infections in ArgentinaS. Fernandez a, L. de Vedia b, M.J. Lopez Furst c, N. Gardella a, S. Di Gregorio , M.C. Ganaha , S. Prieto f, E. Carbone

g, N. Lista , F. Rotrying , M.E. Stryjewski , M. Mollerach .

Aura María Vélez GrandaVanessa Morales Ospina

III Semester

INTRODUCTION

Generalities•Staphylé: “grape”, Coccus: “granule”• Gram positive bacteria.• Diameter of about 0.5-1 um• Includes at least 40 species, 24 subspecies.•Facultative anaerobes.

Staphylococcus

INTRODUCTION

Generalities• Grown in conditions with high concentrations of NaCl (10%) • Temperature 18-40 ° C.• Pathogens in humans.• The non-sporulating bacteria more resistant to heat, desiccation and salinity. • Has in its wall teichoic acid and is sensitive to the enzyme lysostaphin.

Staphylococcus

INTRODUCTION

Generalities• Facultative anaerobes

bacteria. • Gram positive bacteria.• Production of coagulase,

catalase, enterotoxin,thermonuclease

• Stationary and not sporulated.

Staphylococcus aureus

INTRODUCTION

• Scalded skin •syndrome

• Food poisoning

• Toxic Shock Syndrome

• Skin infections

• Bacteremia

• Endocarditis

• Pneumonia

• Osteomyelitis

Diseases caused by S. aureus

INTRODUCTION CA-MRSA

Community-acquired methicillin-resistant


generallyexhibit SCCmec IV or V

commonly carry Panton-Valentine leukocidin

(PVL) genes

Associated with infections involve skin

structures, abscess formation, necrotizing

pneumonia, severe sepsis,

osteomyelitis, meningitis and death

shows greater virulence, spreading more rapidly and causing more severe disease

INTRODUCTION HA-MRSA

hospital associated methicillin-resistant


generallyexhibit SCCmec I, II, III

Panton-Valentine leukocidin (PVL) genes,

rarely identified

Is much less sever than CA-MRSA

infections that occur in hospitals and health centers for poor health care, washing techniques, contamination,

immunosuppression.

They may include surgical wound

infections, urinary tract infections, bloodstream

infections and pneumonia.

INTRODUCTION

Panton –Valentine

Leucocidina(PVL)

is a cytotoxin, a β-toxins pore formers.

LPV presence is associated with increased virulence of certain strains of


It is present in the majority of CA-MRSA

INTRODUCTION SCCmec

Staphylococcal cassette chromosome mec

region of the chromosome of S. aureus, which is a series of genes

encoding and regulate the resistance to methicillin

INTRODUCTIONSCCmec mec

mecA gene

Encoded protein PBP2a

It has a low affinity for β-lactam

Involved in resistance

various types of SCCmec

(I, II, III, IV, V, VI)

INTRODUCTION

acts inhibiting the synthesis of the bacterial cell wall

Methicillinlactam antibiotic - penicillin group

Prevents the formation of cross-links between the linear peptidoglycan polymer chains

are a major component of the cell wall of Gram positive bacteria

INTRODUCTION

Acts by binding and competitive inhibition of

transpeptidase enzyme

used by the bacteria to

generate crosslinks (D-alanyl-alanine)

used in peptidoglycan

synthesis

INTRODUCTION

Staphilococcus

Staphilococcus aureus

CA-MRSAHA-MRSA

SCCmec

Methicillin

INTRODUCTION

ObjetiveStudy and know the clinical characteristics

and genotype of HA-MRSA and CA-MRSA and especially various infections, their prevalence in specific locations and what are the variants

that may have some influence

MATERIALES Y METODOS

ESTUDIO

Multicentrico, prospectivo, observacional

Evalúa características clínicas y moleculares de la invasión

CA - MRSA

Argentina De marzo de 2010 a diciembre de 2011

Pacientes inscritos de 11 hospitales de Argentina , un

total de 55 pacientes

Edad: ≥ 14 años Pacientes para incluirse en el estudio no debían presentar:.Dialisis.Cirugía. Presencia catéteres.Dispositivos médicos.Residido en un centro de cuidado por mucho tiempo.


Información demográfica y clínica por medio de

formularios de in forme clínico

RECOLECCIÓN

Información socio económica a partir de previas revisiones,

fuentes de aislamiento , pruebas de laboratorio



PCR ( Reacción en cadena de la polimerasa)

Es una técnica desarrollada por Karry Mullis en 1980 cuyo objetivo es la amplificación de genes o de un fragmento de

DNA o indirectamente de uno de RNA.

La amplificación permite que aumente el numero de copias de una secuencia particular de DNA

MATERIALES Y METODOS PFGE ( Electroforesis en Gel de campo pulsado)

La PFGE permite la separación de grandes fragmentos de DNA mediante la inducción de

reorientación de una serie de cambios en el campo eléctrico, cuya duración permite saber el intervalo

de tamaños que se pueden separar.

Su utilidad es semejante a la electroforesis convencional, salvo que los fragmentos de DNA

separados son de mayor tamaño.


MLST (Tipificación multilocus de secuencias) es una técnica genética para la

caracterización taxonómica de bacterias y microorganismos.

Su técnica consiste en amplificación mediante PCR seguida de la secuenciación del ADN. Se

pueden rastrear las diferencias en nucleótidos entre cepas en un número variable de genes en función del

nivel de discriminación que se desee.

RESULTADOS

RESULTADOS

Los MRSA aislados fueron mas sensibles a la

Vancomicina, además ninguno de los

aislamientos fueron multiresistentes.

RESULTADOS

RESULTADOS

Clon ST3023 Aislamientos con

subtipos

C1 16 aislamientos

C2 a C6, 7 aislamientos

SCCmec Tipo IVa Spa T019

Agr IIIPFGE Type C

RESULTADOS

Clon ST5 2 Aislamientos

SCCmec Tipo IVa Spa t311 t2724

Agr IIPFGE Type A

RESULTADOS

Clon ST72 2 Aislamientos

SCCmec Tipo IV, IVvarSpa t1364

t148a

Agr IPFGE Type F

RESULTADOS

Clon STND 1 Aislamiento

SCCmec Tipo IV Spa t002

Agr IIPFGE Type F

RESULTADOS

RESULTADOS

DISCUSSIONInvestigator´s Principal Statement Agree or Disagree

Ma et al, 2002 Antimicrobial resistance patterns have been used to distinguishbetween CA-MRSA and HA-MRSA strains

Agree

Gardellan et al., 2008 The molecular characteristics shared by the isolates this major clone largely that reported for a minorclone described in our previous study,

Agree

Gardella et al., 2008; Sola et al., 2008

One of the minor clonesfound in this study (n = 2), the CAA clone, (PFGE type A, ST5-SCCmec IV-spa t311), had been identified as prevalent in Argentinasince 2004

Agree

Deleteo et al. , 2010 In contrast to other clones whichhave been described to have a certain continent specificity, ST30 isdistributed world wide

Agree

CONCLUSIONS• Finally this study is very important for us because it allows us to know variation and the pathogen of these clones behavior, giving us excellent bases at the time of developing a

gene therapy and have new therapeutic targets that avoids these develop their

virulence.

• Also the study allows also analyzing at the level of the community that things must take into account that levels of prevention should be developed within the communities to re-

establish the infectious effects of strains.

CONCLUSIONS• The knowledge of this study brings us to the

awareness and the recognition of the different infections caused by the different S. aureus clones and the consequences that has caused with its constant prevalence that

is no longer only if no community hospital, by what has become a global concern and will

continue to evolve

• discover the importance of describing the clinical, molecular and epidemiological of current invasive infections caused by HA-

MRSA and CA-MRSA

Health & Medicine

Seminario biolo molecular