Methicillin-resistant Staphylococcus aureus ST30-SCCmec IVc clone as the major cause of...
-
Upload
auritam93 -
Category
Health & Medicine
-
view
49 -
download
0
Transcript of Methicillin-resistant Staphylococcus aureus ST30-SCCmec IVc clone as the major cause of...
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
Staphylococcus aureus
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
Staphylococcus aureus
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
Staphylococcus aureus
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.
MATERIALES Y METODOS
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
MATERIALES Y METODOS
MATERIALES Y METODOS
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.
MATERIALES Y METODOS
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