Diversity and dynamics of antibiotic-resistant bacteria in cheese

Ana Mercedes Vanegas y Catalina Salazar.

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.

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.

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.

FOOD COMIDA ALIMENTS CIBO

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 persistenIncrementa el riesgo de propagación

MATERIALES Y MÈTODOS

EXTRACCIÓN DEL ADN

Lisis celular

Adición de la RNAasa (opcional)

Precipitación del proteínas

Precipitación de ADN con isopropanol

Almacenamiento en TE

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

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

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

RESULTADOSFig.2

SIN ANTIBITICOS TETRACICLINA ERITROMICINA

3 7 15 30 60

Fig.3

Fig.4

Fig.5

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 […]”

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.

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.

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.