This article reports the composition of tetracycline and erytromicine-resistant bacterial communities in a model of cheese, monitored by PCR-DGGE

1. Ana Mercedes Vanegas y Catalina Salazar.

2. INTRODUCTION
This article reports the composition of tetracycline and
erytromicine-resistant bacterial communities in a model of
cheese, monitored by PCR-DGGE (that is the polymerase chain
reaction denaturing gradient gel eletrophoresis).
Bacterial resistance consist that a micro-organism presents
antibiotic resistance to a drug so the drug is not good enought to
cure the infection.
The most common bacterial resistant groups determinated in the
article were: Eschericcia Coli, Lactococcus lactis, enterococcus
faecalis and staphylococcus; but the counts of antibiotic
resistance varied widely depending on the groups examined.

3. GENERAL OBJECTIVE
Examine the diversity and dynamics of antibiotic
resistant bacterial communities of a traditional
cheese during the manufacture and ripening, using
the PCR-DGGE technique.

4. NOTES..
Food is one of the most common
vias that bacterias use to spread
the resistance.
Fermented food as cheese are key
players in the transmition of
antibiotic resistance.
 Cheese made of raw-milk have
been reported to contain the
highest grades.

5. MATERIALES Y MÈTODOS
RESISTENCIA MICROBIANA
Resistencia de un microorganismo a un medicamento antimicrobiano al que
originalmente era vulnerable.
Los organismos resistentes pueden resistir ataques de
medicamentos antimicrobianos tales como
antibióticos, fungicidas, antivirales y antipalúdicos
Los tratamientos convencionales se vuelven ineficaces
• Bacterias
• Hongos
• virus
• parásitos
Infecciones persisten
Incrementa el riesgo
de propagación

6. MATERIALES Y MÈTODOS
EXTRACCIÓN DEL ADN
Lisis celular
Adición de la RNAasa (opcional)
Precipitación del proteínas
Precipitación de ADN con isopropanol
Almacenamiento en TE

7. MATERIALES Y MÈTODOS
PCR DGGE
Es una electroforesis que permite la separación de
fragmentos de ADN del mismo tamaño pero con
diferente secuencia de nucleótidos.
Electroforesis en gel con gradiente desnaturalizante

8. PCR DGGE
Agentes químicos
desnaturalizantes del
ADN (una mezcla de
urea y formamida) se
incorpora a lo largo
de un gel de
poliacrilamida
Se mantiene una
temperatura
constante de 50-
65 °C
Fragmentos de ADN de doble
cadena migran por el gel
Encuentran una determinada
concentración de urea y
formamida (concentración
desnaturalizante)
Las cadenas se separan localmente y
el desplazamiento de las moléculas
disminuye o se interrumpe

9. Tomada de: http://www2.inecc.gob.mx/publicaciones/libros/710/dgge.pdf

10. RESULTADOS
Fig.2
SIN ANTIBITICOS TETRACICLINA ERITROMICINA
3 7 15 30 60

11. Fig.3

12. Fig.4

13. Fig.5

14. AUTHOR FACT
Rossi
“It has also been speculated
that environmental conditions
during fermentation and/or
ripening might contribute to the
maintenance of antibiotic
resistance in food-borne
bacteria”
EFSA
“Species of this genus are
thought to act as a reservoir of
antibiotic resistance genes, from
which they might be transferred
to food-borne pathogens”
Florez,
Divergilis &
Wang
“Large numbers of antibiotic-
resistant bacteria and genes
have been repeatedtly reported
in fodds, including diary
products”
Pesavento &
Divergilis
“The PCR-DGGE profiles of
tetracycline and erytromicine-
resistant population were
compossed mainly of L. lactis
and Enterococus spp […]”

15. CONCLUSIONS
We think that this study will be useful for the companies that make
fermented food like cheese, because they discovered that this
kind of food have a lot of microorganisms that can replicate and
produce antibiotic resistance, so they have to improve their
hygienic techniques during the fermentation process.
This article help us to understand how does the
antibiotic resistance works and what
techniques are used nowadays.

16. We think that is important to know about bacterial resistance
because it is related to our career, specially when a patient
presents it.
We think that the article lead us to try to be more careful with the
food we buy and the places where we buy it or where it comes
from.

19. BIBLIOGRAFIA
• BELEN Flórez Ana; BALTASAR Mayo. Departamento de Microbiología
y Bioquímica. Instituto de productos lácteos de Asturias. DIVERSITY
AND DYNAMICS OF ANTIBIOTIC RESISTANT BACTERIA IN CHEESE AS
DETERMINATED BY PCR DENATURING GRADIEN GEL
ELECTROPHORESIS. (July 2015) International Journal of Microbiology.
• MARTINEZ Sánchez, Lina María; VARGAS Grisales, Natalia; MEJIA
Cardona, Laura; OSORIO Ospina Felipe; RAMIREZ Pulgarin, Sergio.
Biología Molecular 8ed. Editorial Universidad Pontificia Bolivariana
2015.
• DRLICA, Karl; S. PERLIN, David; Antibiotic Resistance - Understanding
and responding to an emerging crisis. 2011 by Pearson Education,
Inc.