BY: Dana Marcela Trujillo Quintero

1. DANA MARCELA TRUJILLO QUINTERO
TERCER SEMESTRE
FACULTAD DE MEDICINA
UNIVERSIDAD PONTIFICIA BOLIVARIANA
2019-2

2. INTRODUCTION
 Gramnegative bacteries
 Habitants of the digestive system of
humans and animals and
microflora in natural environments.
 Stick shape
 1-3 μm long and 0.5 μm in
diameter.
Escherichia
Klebsiella
Salmonella
Enterobacter
LOCATION OF INFECTIONS
Central Nervous System
Lower respiratory tract
Bloodstream
Digestive tract
Urinary tract
• ENTEROBACTERY

3. INTRODUCTION
COLISTINA
 An antimicrobial to treat gram-negative
bacteria
 Treatment of multi-resistant germ
infections
 Alter the permeability of the wall of
sensitive gram negative bacteria, as a
consequence the drug enters and
produces the bactericidal effect.
Mcr-1
 It is a plasmid mechanism of colistin
resistance
 It codes for an enzyme of the
phosphoethanolamine transferase family
that modifies the structure of Lipid A of
the bacterial wall.

4. OBJECTIVE
Investigate colistin-resistant
mcr-Positive
Enterobacteriaceae in fresh
vegetables, and increasing
infectious threat in China

5. MATERIALES Y MÉTODOS
MIC:
¿para que?
Determinar la sensibilidad
de las bacterias a un
antimicrobiano y la mínima
cantidad que es capaz de
impedir el crecimiento del
microorganismo.
Fundamento
Exposición de un grupo de
microorganismos a discos
de antibióticos en placas
de agar.
S= SENSIBLE I= INTERMEDIA R= RESISTENTE

6. MATERIALES Y MÉTODOS
MÉTODO DE E-TEST METODOS AUTOMATIZADOS
 utilizan sistemas de microdilución en
medio líquido sobre microplacas con
pocillos en "U" e interpretan el
crecimiento bacteriano en los diferentes
pocillos por medio de un autoanalizador.
 emplean tiras plásticas impregnadas en
concentraciones crecientes de
antibiótico indicadas en una escala
graduada sobre la propia tira.

7. PFGE
¿Para qué?
Para separar fragmentos de DNA de
una longitud superior a 20-40kb
Fundamento
En gel de agarosa al 1%, alterar
periódicamente la orientación del
campo eléctrico activando
alternativamente dos pares de
electrodos.

8. RFLP
¿Para qué?
Estudiar las variaciones en las
moléculas de DNA
(Polimorfismos genéticos)
Fundamento
Fragmentación del DNA en
sitios de restricción por las
enzimas de restricción

9. RESULTADOS
CIM > 2 mg/l

10. RESULTADOS

11. RESULTADOS

12. RESULTADOS

13. DISCUSSION
AUTHOR CONTRIBUTION YES OR NOT
Shen Y, et al Isolate RL76 belonged to ST10, a prevalent ST of clinical isolates
harboring mcr-1 in China.
Liu BT, et al Sixteen MLST types were identified in 23 E. coli isolates, indicating
the genetic diversity of these strains.
Sun J, et al The disemination of mrc-1 among Enterobacteriaceae in fresh
vegetables was mediated by incX4 and incI2 conjugative
plasmids, and both could confer the spread of mcr-1 in
enterobacteriaceae from humans and animals

14. CONCLUSIONS
The discovery of colistin resistance mediated by the mcr-
1 gene demonstrates that bacteria are becoming
stronger against the most effective antibiotics to fight
them, representing a public health problem.
Through molecular biology we can carry out these types
of studies that allow us to identify resistance genes or, for
example, genetic abnormalities in humans. This allows us
to take actions to take control of the spread of the gene
or to prevent diseases from expressing themselves, being
a very useful tool.