This document discusses Staphylococcus aureus and antibiotic resistance. It analyzed 34 isolated S. aureus samples from a hospital in China. Antibiotic susceptibility testing found high resistance to erythromycin (95.2%) but no mutations conferring resistance to fusidic acid or mupirocin. Multilocus sequence typing of resistance genes identified mutations in genes related to macrolide and mupirocin resistance in 23 of 28 samples. The overuse of antibiotics is increasing resistance, demonstrating the need for prudent antibiotic use and resistance monitoring to preserve treatment options.

1. Ana Sofía Cortés
Sofía Echavarría Restrepo
Estudiantes de medicina
Tercer semestre
Biología molecular

2. https://co.pinterest.com/pin/289919294748498973/
Introduction

3. STAPHYLOCOCCUS
¿WHAT ARE THEY?
The genus staphylococcus is
located in the family
micrococcaceae, which are gram-
positive cocci, are arranged in
groups of irregular clusters
¿WHERE ARE THEY ?
They grow and various
conditions, but they do better at
temperatures of 30 ° and 37 ° C
and at a pH of 7
Staphylococus

4.
Grow in culture media
containing blood as typical
colonies of creamy consistency
BIOCHEMICAL ASPECT:
They produce enzymes such as
catalase and coagulase, have the
ability to ferment mannitol and
trehalase, and produce a
thermonuclease.
In humans it can exist within the
normal flora of skin and mucous
membranes
In patients undergoing medical
procedures such as hemodialysis
and surgeries are given high
rates
STAPHYLOCOCCUS AUREUSStaphylococus Aureus

5. TOXINS
alpha toxins: development of
edemas and tissue damage by
change in permeability in the
cells
Beta toxins: properties are
increased by erythrocyte
exposure at low temperatures
Gamma toxins: induction in
inflammation
alpha toxin: produces lysis of
different cell types

6. MACROLIDES
Are a group derived from
the metabolic products of a
Streptomyces erythreus
strain.
H a s i n c o m m o n t h e
macrocyclic ring of lactone.
MECHANISM OF ACTION:
Reversible binding to the
50s subunit of ribosomes,
blocking transpeptidation
or translocation reactions,
inhibition of protein
synthesis and inhibition of
cell growth.
Inhibit cytochrome P450

7. TYPES OF MACROLIDES
• Erythromycin
• Azithromycin:
against
protozoos
• Clarithromycin
: leprosy and
erradication oh
Helycobacter
Pylori
• Flurithromyci,
Spiramycin: do
not affect
cytochrome
P450
• Mepartricin:
bening
protopic
hiperplasia.

8. FUSIDIC ACID
Used to treat diseases, like acute osteomielitis, septic
arthritis and other infections.
Mechanism of action: inhibits bacterial proteins
synthesis by preventing the turnover of fusE
encoded elongation factor G from the ribosome.
Any damage in this gene
ususally lead to the high level
resistance of FA

9. MUPIROCIN
✴ Pseudonomic acid A
✴ Used to treat skin, and postoperative
wound infections.
✴ Mechanism of action: is reversibly
bound to isoleucine- t RNA synthetasa
and inhibits the synthesis of bacterial
proteins.
✴ its activity is limited to gram-positive
bacteria, staphylococci and streptococci

10. BACTERIA RESISTANCE
RESISTANCE CLASSES:
1. environmental
2. natural-intrinsic
3. acquired
how to face the problem of
resistance:
Rational use of antibiotics,
epidemiological surveillance
and the implementation of
strategies for treatment.
Resistance mechanism:
1. Inactivation of antibiotic
2. Alteration of the passge of the drug form the exterior to the
interior
3. Alteration in sites or targets of the antibiotic

11. OBJECTIVE
In recent years it has been
shown that resistance to
multiple antibiotics has
increased
This article, through the S
aureus study of the
university hospital east of
C h i n a , w a n t s t o
understand the genetic
d i v e r s i t y o f t h e
microorganism and the
reasons why bacterial
resistance is occurring

12. Materiales y métodos

13. AISLAMIENTO
34 S. aureus aislados no duplicados,
incluidos 6 MRSA.
Hospital Lishu Central en la provincia
de Zhejiang
De diferentes tejidos como sangre,
orina, esputo, abcesos y exudados de
herida.
¿CUÁNTO SE UTILIZO?
¿DÓNDE CONSIGUIERON LA ESPECIE?
¿DE CUÁLES TEJIDOS?

14. PCR
OBJETIVO: amplificación directa de un gen o
fragmento de ADN, o indirecta de un ARN.
ETAPAS DEL PROCESO:
1. desnaturalización
2. alineamiento
3. síntesis
Se necesita H2O, buffer, ADN,DNTP,
primers, polimerasa
CARACTERÍSTICAS:
1. rendimiento
2. duración
3. especificidad
4. capacidad de detección
5. fidelidad

15. TEST DE SUCEPTIBILIDAD AL
ANTIBIOTICO
Es la mínima cantidad de antimicrobiano que es capaz de
impedir el crecimiento de un microorganismo en unas
condiciones normalizadas.
Este método nos ofrece información sobre la sensibilidad de
las bacterias S (sensible), I (intermedia) y R (resistente).
MIC
FA: bajo nivel 2 a
64 μg/ ml , > o
= a 128 de alta
resistencia
MUPIROCINA: bajo
nivel 8 a 256
μg /ml y una de
alto nivel > o =
a 512 μg / ml

16. EXTRACCION DEL ADN
1. Lisis celular:
con una temperatura adecuada (37°) y 1ml de LB
estéril. Centrifugacion de 13000xg por 2 minutos
2. Degradación de ARN:
a partir de una ARNasa se degrada el ARN para que
quede el ADN.
3. Precipitación de las proteínas:
con acido acético
4. Precipitacion de ADN:
isopropanol
5. Almacenamiento:
se almacena con TE ( T de tris y E de edta )

17. Amplificación de PCR y secuencia de ADN

18. PFGE
F u n d a m e n t o :
separación de moléculas
grandes, en función de
la mayor o menor
dificultad que presentan
para moverse
Variables:
voltaje del
campo
eléctrico
Concentración
del gel de
agarosa
Tiempo de los
pulsos
Fuerza iónica
del
amortiguador
Temperatura

19. PASOS A REALIZAR:
‣ Preparacion de los cromosomas del parasito
‣ Electroforesis en campo pulsado
‣ Tranferencia a membrana de nylon
‣ Hibiridacion con sondas moleculares apropiadas.

20. MLSTTécnica genética para la
caracterización taxonómi
c a d e b a c t e r i a s y
microorganismos.
La técnica consiste en
a m p l i fi c a c i ó n
mediante PCR seguida
de la secuenciación del
ADN. Se pueden rastrear
l a s d i f e r e n c i a s e n
nucleótidos entre cepas
en un número variable
de genes en función del
nivel de discriminación
que se desee.

21. EL FLUJO DE TRABAJO DE LA MLST IMPLICA:
1) recolección de los datos
2) análisis de los datos
3) análisis multilocus de las secuencias.
De 23 variedades resistentes de S aureus se amplificaron y secuenciaron siete
genes de mantenimiento arcc, aroe, glpf, gmk, pta, tpi y yqil

22. Results

23. ANTIMICROBIAL SUSCEPTIBILITY TESTING WAS PERFORMED
beta-lactam antibiotics,
which include the
penicillins (methicillin,
dicloxacillin, nafcillin,
oxacillin, etc.) and the
cephalosporins

25. FUSIDIC
ACID
fusA*H
fusB/C/D
fusE

26. MUPI
ROCIN
x MupA
x MupB

27. MACRO
LIDES

29. Macrolide-resistant S.aureus and
Methicillin-resistant S. aureus could be
ERADICATED by FA and mupirocin
*inclination, develop
multi drug resistance

30. Gene mutations 23 of 28 (macrolide and
mupirocin)
No FA mutations were found

33. Discussion

34. Erythromycin 1980 Gram + Gram – More use, more
resistance
ERYTHROMYCIN RESISTANCE
95.2%
77.5%
51.7%
37.4%
42%
73.5%

35. Kirst HA
Macrolide antibiotics are an old and well-
established class of antimicrobial agents that have
long played a significant role in the chemotherapy
of infectious diseases
Liu Y, Kong F, Zhang X, Brown M, Ma L and
Yang Y
Penicillin and erythromycin are no longer
appropriate agents. Effective antibiotic agents for
patients with impetigo are mupirocin and fusidic
acid
Baek YS, Jeon J, Ahn JW and Song HJ The rate of resistance to oxacillin (methicillin-
resistant S. aureus [MRSA]) was 47.4%. Similar
rates of resistance to erythromycin (45.6%).
Castanheira M, Watters AA, Mendes RE, Farrell
DJ and Jones RN
Ireland and Greece showed the highest S. aureus
fusidic acid resistance levels, with low rates of
acquired fusidic acid resistance genes. Isolates
from these countries displayed MIC values of > or
= 512 mg/L, the presence of the elongation
factor G L461K alteration and clonal occurrences

36. Conclusions
FA and mupirocin are
the choice treatment
for S. aureus
infections
The overuse of
antibiotics is a red
flag for the world
health
The fact that bacteria
is developing
unknown ways to be
resistant should be
alarming because of
possible new diseases
Multi drug resistance
bacteria is more
common every day
Education in the use
of antibiotics is vital

37. CMAP TOOLS

38. Ana Sofía Cortés Porras

39. Sofía Echavarría Restrepo

40. Gracias