Behavior and changes in cell morphology ofEscherichia coliO157:H7 in liquid medium and skim milk in the presence of caffeine

Abstract

Behavior and changes in cell morphology of Escherichia coli O157:H7 in liquid medium and skim milk in the presence of caffeine Comportamiento y cambios en la morfología celular de Escherichia coli O157:H7 en un medio líquido y en leche descremada en presencia de cafeína The objective of this study was to investigate the antibacterial effect of caffeine on the behavior and changes in cell morphology of E. coli O157:H7 in a liquid medium and in skim milk. The inhibitory effect of caffeine at different concentrations was determined by inoculating E. coli O157:H7 in laboratory medium and skim milk samples. Samples were incubated at 37ºC for 48 h, and E. coli O157:H7 population was enumerated. Our results showed that caffeine significantly (P < 0.05) inhibited the growth of E. coli O157:H7 in laboratory medium and milk samples. A greater than 3.0 log CFU ml −1 inhibition was observed in milk containing 5.0 g/L caffeine within 12 h of incubation. Moreover, using flow cytometry, marked changes in the morphology of E. coli O157:H7 were also observed. Caffeine has potential as an antimicrobial agent and could be used as an effective natural additive to improve the safety of food products.Keywords: E. coli O157:H7; caffeine; inhibition; milk; flow cytometry El objetivo del presente estudio fue investigar el efecto antibacteriano que tiene la cafeína sobre el comportamiento y los cambios de la morfología celular de E. coli O157:H7 en un medio líquido y en leche descremada. Se determinó el efecto inhibitorio de distintas concentraciones de cafeína, inoculando E. coli O157:H7 en muestras de un medio de laboratorio y de leche descremada. Dichas muestras fueron incubadas a 37°C durante 48 horas, enumerándose posteriormente la población de E. coli O157:H7. Los resultados demostraron que la cafeína inhibió significativamente (P < 0,05) el crecimiento de E. coli O157:H7 tanto en las muestras del medio de laboratorio como en la muestra de leche. En la leche descremada que contenía 5,0 g/L de cafeína, se observó una inhibición mayor a 3,0 log CFU ml -1 , ocurrida dentro de las 12 horas de incubación. Asimismo, a partir del uso de una citometría de flujo se observaron cambios significativos en la morfología de E. coli O157:H7. La cafeína tiene el potencial de ser un agente antimicrobiano, por lo cual podría utilizarse como un aditivo natural efectivo para mejorar la seguridad de los productos alimenticios.Palabras Claves: E. coli O157:H7/; cafeína; inhibición; leche citometría de flujo

Effect of Catechins, Green tea Extract and Methylxanthines in Combination with Gentamicin Against Staphylococcus aureus and Pseudomonas aeruginosa - Combination therapy against resistant bacteria -

“…In other studies, caffeine was able to decrease the minimum inhibitory concentration (MIC) values of gentamicin against S. aureus and P. aeruginosa [20, 21]. Previously, the antimicrobial properties of caffeine against Candida albicans were demonstrated [22, 23]. Based on the above, the aim of the present study was to evaluate the antibacterial activities of caffeine, green tea extract, EGC, and EGCG alone and in combination with gentamicin against two clinically important bacteria, S. aureus and P. aeruginosa .…”

Use of Energy Drinks Among College Students in Saudi Arabia

“…Caffeine is also contained in coffee, tea, chocolate, and many other food sources like cola and is used by many students as a stimulant [7,8]. Even though the physiological mechanisms of caffeine are not well understood, caffeine beneficially affects performance by reducing the perception of fatigue, enhancing central drive, and/or improving exercise capability [9].…”

Effects of Omeprazole and Caffeine Alone and in Combination with Gentamicin and Ciprofloxacin Against Antibiotic Resistant Staphylococcus Aureus and Escherichia Coli Strains

“…Previously, it was confirmed that caffeine was able to decrease the MIC values of gentamicin against S. aureus and P. aeruginosa [ 14 , 15 ]. Additionally, the antimicrobial properties of caffeine against Candida albicans were reported [ 16 , 17 ]. Different mechanisms have been mentioned about antibacterial activity of caffeine such as inhibiting incorporation of adenine and thymidine in the synthesis of DNA via inhibition of thymidine kinase and also inhibiting the synthesis of DNA [ 18 , 19 ].…”