The major cause of community-acquired invasive infections in Argentina is found to be the ST30-SCCmec IVc clone of methicillin-resistant Staphylococcus aureus (MRSA). Of the 55 community-acquired MRSA isolates studied, 23 belonged to the ST30 clone. The isolates were sensitive to vancomycin and none were multidrug-resistant. Molecular analysis found the ST30 isolates carried SCCmec type IVa, spa type T019, and were of agr type IIIPFGE. The study provides insight into the virulence and spread of MRSA clones globally.

1. Methicillin-resistant Staphylococcus aureus ST30-SCCmec IVc clone as the
major
cause of community-acquired invasive infections in Argentina
S. 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 Granda
Vanessa Morales Ospina
III Semester

2. 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

3. 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

4. INTRODUCTION
Generalities
• Facultative anaerobes
bacteria.
• Gram positive bacteria.
• Production of
coagulase, catalase, entero
toxin,
thermonuclease
• Stationary and not
sporulated.
Staphylococcus aureus

5. INTRODUCTION
• Scalded skin
•syndrome
• Food poisoning
• Toxic Shock
Syndrome
• Skin infections
• Bacteremia
• Endocarditis
• Pneumonia
• Osteomyelitis
Diseases caused by S.
aureus

6. INTRODUCTION
Community-acquired
methicillin-resistant
Staphylococcus aureus
generally
exhibit 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

7. INTRODUCTION
hospital associated
methicillin-resistant
Staphylococcus aureus
generally
exhibit 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, immunosup
pression.
They may include
surgical wound
infections, urinary tract
infections, bloodstream
infections and
pneumonia.

8. INTRODUCTION
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

9. INTRODUCTION
Staphylococcal cassette chromosome mec
region of the chromosome of
S. aureus, which is a series of genes
encoding and regulate the resistance
to methicillin

10. INTRODUCTION
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)

12. INTRODUCTION
acts inhibiting the synthesis of the
bacterial cell wall
lactam 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

13. INTRODUCTION
Acts by binding and
competitive
inhibition of
transpeptidase
enzyme
used by the
bacteria to
generate crosslinks
(D-alanyl-alanine)
used in
peptidoglycan
synthesis

14. INTRODUCTION
Staphilococcus
Staphilococcus
aureus
CA-MRSA
HA-MRSA
SCCmec
Methicillin

15. INTRODUCTION
Objetive
Study 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

16. 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

17. 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

18. 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

19. 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

20. 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.

21. 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.

22. RESULTADOS

23. RESULTADOS

24. Los MRSA aislados fueron
mas sensibles a la
Vancomicina, además
ninguno de los
aislamientos fueron
multiresistentes.
RESULTADOS

25. RESULTADOS

26. Clon ST30
23 Aislamientos con
subtipos
C1 16
aislamientos
C2 a C6, 7
aislamientos
SCCmec Tipo IVa Spa T019
Agr IIIPFGE Type C
RESULTADOS

27. Clon ST5 2 Aislamientos
SCCmec Tipo IVa
Spa t311
t2724
Agr IIPFGE Type A
RESULTADOS

28. Clon ST72 2 Aislamientos
SCCmec Tipo IV, IVvar
Spa t1364
t148a
Agr IPFGE Type F
RESULTADOS

29. Clon STND 1 Aislamiento
SCCmec Tipo IV Spa t002
Agr IIPFGE Type F
RESULTADOS

30. RESULTADOS

31. DISCUSSION
Investigator´s Principal Statement Agree or Disagree
Ma et al, 2002 Antimicrobial resistance patterns have
been used to distinguish
between 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 minor
clone described in our previous study,
Agree
Gardella et al., 2008; Sola et al.,
2008
One of the minor clones
found in this study (n = 2), the CAA
clone, (PFGE type A, ST5-
SCCmec IV-spa t311), had been
identified as prevalent in Argentina
since 2004
Agree
Deleteo et al. , 2010 In contrast to other clones which
have been described to have a certain
continent specificity, ST30 is
distributed world wide
Agree

32. 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.

33. 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