scholarly journals Evaluación del efecto antimicrobiano de una mezcla de probióticos frente a Cronobacter sakazakii y Salmonella enterica en preparados para lactantes reconstituidos para lactantes

2020 ◽  
Vol 34 ◽  
pp. 27-37
Author(s):  
C. Candel-Pérez ◽  
R. García-Iborra ◽  
J. García-Alonso ◽  
Mª Carmen Martínez-Gracia
Keyword(s):  
Salmonella Enterica ◽  
Incubation Temperature ◽  
Lactobacillus Rhamnosus ◽  
Antimicrobial Effect ◽  
Cronobacter Sakazakii ◽  
Inhibitory Mechanism ◽  
Bifidobacterium Infantis ◽  
Ph Values ◽  
Infant Formulae ◽  
Temperature Interaction

Cronobacter sakazakii y Salmonella enterica son considerados patógenos capaces de causar sepsis y meningitis en lactantes. Se han descrito casos de infección por estos patógenos asociados al consumo de preparados para lactantes contaminados. La inclusión de probióticos en los preparados, además de su papel en la modulación de la microbiota intestinal, podría ser útil para contrarrestar la contaminación de microorganismos patógenos de estos productos una vez reconstituidos y, por lo tanto, reducir el riesgo de infección. El objetivo de esta investigación fue evaluar el efecto antimicrobiano de una mezcla de probióticos (Lactobacillus rhamnosus y Bifidobacterium infantis) frente a Cronobacter sakazakii y Salmonella enterica en preparados reconstituidos para lactantes. Las muestras (con o sin probióticos) se inocularon con C. sakazakii o S. enterica y se incubaron a 30 o 40ºC durante 72 horas. Los resultados muestran que la presencia de probióticos en los preparados lácteos no tiene un marcado efecto en el crecimiento de los patógenos. Sin embargo sí se ve potenciado su efecto inhibitorio frente a C. sakazakii por la interacción entre la temperatura de incubación y los probióticos. Los probióticos empleados fueron viables durante todo el período de incubación, por lo que el agotamiento de los nutrientes se descartó como posible mecanismo de inhibición. La disminución del pH en los preparados lácteos inoculados no explica de manera satisfactoria un comportamiento tan diferente entre ambos patógenos. Por lo tanto, se sugiere como posible mecanismo inhibidor la liberación de bacteriocinas específicas con acción contra C. sakazakii pero sin efecto contra Salmonella. Se deben realizar estudios adicionales para probar esta hipótesis.   Cronobacter sakazakii and Salmonella enterica have been implicated in outbreaks causing sepsis and meningitis in infants. Several infection cases have been associated with the consumption of contaminated powdered infant formulae. Besides its role in modulating gut microbiota, the inclusion of probiotics in infant formulae may be useful to counteract pathogen contamination in these products and thus to reduce the risk of infection. The aim of this research was to evaluate the antimicrobial effect of a mixture of the probiotics Lactobacillus rhamnosus and Bifidobacterium infantis against Cronobacter sakazakii and Salmonella enterica in reconstituted follow-on formulae. For that, infant formulae (with or without probiotics) were inoculated with either C. sakazakii or S. enterica and incubated at 30 or 40ºC for 72 hours. Overall, the results showed the presence of probiotics inhibiting the growth of C. sakazakii together with incubation temperature (interaction between both factors). Probiotics were viable throughout the incubation period so that nutrient exhaustion could be ruled out as the mechanism of C. sakazakii inhibition. Thus, the acidification of media observed during the study was hypothesized to be responsible for pathogen growth inhibition. However, since in the case of formulae inoculated with Salmonella the behavior of probiotics and pH values was similar to C. sakazakii, the decrease of pH does not satisfactorily explain such a different behavior. So, it is suggested that the production of specific bacteriocins by probiotics against C. sakazakii but not against Salmonellla could be the underlying inhibitory mechanism. Further studies should be carried out to test this hypothesis.

scholarly journals Characterisation of Lactobacillus rhamnosus VT1 and its effect on the growth of Candida maltosa YP1

2008 ◽  
Vol 25 (No. 5) ◽  
pp. 272-282 ◽  
Author(s):  
D. Liptáková ◽  
Ľ. Valík ◽  
A. Lauková ◽  
V. Strompfová
Keyword(s):  
Growth Rate ◽  
Incubation Temperature ◽  
Lactobacillus Rhamnosus ◽  
Microbial Interactions ◽  
Lag Phase ◽  
Regression Equations ◽  
Candida Maltosa ◽  
Food Protection ◽  
Spoilage Yeast ◽  
Standard Response

The combined effect of initial amount of 18 h <i>L. rhamnosus</i> VT1 inoculum and incubation temperature on the growth of <i>Candida maltosa</i> YP1, an oxidative food spoilage yeast strain, was primarily modelled and studied by standard response surface methodology. This study resulted in the following linear regression equations characterising lag time and growth rate of <i>C. maltosa</i> YP1 in milk in competition with the potentially protective lactobacillus strain. Lag-phase of <i>C. maltosa</i> was strongly influenced by the amount of lactobacillus inoculum (<i>V</i><sub>0</sub>) and incubation temperature (1/<i>T</i>). The synergic effect of both these factors was also evident as results from the equation lag = –33.50 + 186.38 × <i>V</i><sub>0</sub> × 1/<i>T</i> + 512.27 × 1/<i>T</i> – 5.511 × <i>V</i><sub>0</sub> (<i>R</i><sup>2</sup><sub>(λ)</sub> = 0.849). The growth rate was sufficiently described by the linear relation: <i>Gr</i><sub>Cm</sub> = –0.00046 + 0.0033 × <i>T</i> – 0.0016 × <i>V</i><sub>0 (<i>R</i><sup>2</sup><sub>(Gr)</sub> = 0.847). On the basis of these equations, the mutual microbial interactions and the potential application of the lactobacillus strains to food protection are discussed.

scholarly journals Influence of Bacterial Competitors on Salmonella enterica and Enterohemorrhagic Escherichia coli Growth in Microbiological Media and Attachment to Vegetable Seeds

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 285
Author(s):  
Da Liu ◽  
Ronald Walcott ◽  
Kevin Mis Solval ◽  
Jinru Chen
Keyword(s):  
Escherichia Coli ◽  
Foodborne Pathogens ◽  
Salmonella Enterica ◽  
Lactobacillus Rhamnosus ◽  
Probiotic Bacterium ◽  
Enterohemorrhagic Escherichia Coli ◽  
Biocontrol Agents ◽  
Human Pathogens ◽  
Bacterial Strains ◽  
Pathogen Populations

Interests in using biological agents for control of human pathogens on vegetable seeds are rising. This study evaluated whether probiotic bacterium Lactobacillus rhamnosus GG, bacterial strains previously used as biocontrol agents in plant science, as well as a selected plant pathogen could compete with foodborne human pathogens, such as Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC), for growth in microbiological media and attachment to vegetable seeds; and to determine whether the metabolites in cell-free supernatants of competitive bacterial spent cultures could inhibit the growth of the two pathogens. The results suggest that the co-presence of competitive bacteria, especially L. rhamnosus GG, significantly (p < 0.05) inhibited the growth of Salmonella and EHEC. Cell-free supernatants of L. rhamnosus GG cultures significantly reduced the pathogen populations in microbiological media. Although not as effective as L. rhamnosus GG in inhibiting the growth of Salmonella and EHEC, the biocontrol agents were more effective in competing for attachment to vegetable seeds. The study observed the inhibition of human bacterial pathogens by competitive bacteria or their metabolites and the competitive attachment to sprout seeds among all bacteria involved. The results will help strategize interventions to produce vegetable seeds and seed sprouts free of foodborne pathogens.

scholarly journals pH-, Lactic Acid-, and Non-Lactic Acid-Dependent Activities of Probiotic Lactobacilli against Salmonella enterica Serovar Typhimurium

2005 ◽  
Vol 71 (10) ◽  
pp. 6008-6013 ◽  
Author(s):  
Domitille Fayol-Messaoudi ◽  
Cédric N. Berger ◽  
Marie-Hélène Coconnier-Polter ◽  
Vanessa Liévin-Le Moal ◽  
Alain L. Servin
Keyword(s):  
Lactic Acid ◽  
Growth Phase ◽  
Salmonella Enterica ◽  
Lactobacillus Rhamnosus ◽  
Stationary Growth Phase ◽  
Exponential Growth Phase ◽  
Killing Activity ◽  
Serovar Typhimurium ◽  
Probiotic Strains ◽  
Probiotic Lactobacilli

ABSTRACT The mechanism(s) underlying the antibacterial activity of probiotic Lactobacillus strains appears to be multifactorial and includes lowering of the pH and the production of lactic acid and of antibacterial compounds, including bacteriocins and nonbacteriocin, non-lactic acid molecules. Addition of Dulbecco's modified Eagle's minimum essential medium to the incubating medium delays the killing activity of lactic acid. We found that the probiotic strains Lactobacillus johnsonii La1, Lactobacillus rhamnosus GG, Lactobacillus casei Shirota YIT9029, L. casei DN-114 001, and L. rhamnosus GR1 induced a dramatic decrease in the viability of Salmonella enterica serovar Typhimurium SL1344 mainly attributable to non-lactic acid molecule(s) present in the cell-free culture supernatant (CFCS). These molecules were more active against serovar Typhimurium SL1344 in the exponential growth phase than in the stationary growth phase. We also showed that the production of the non-lactic acid substance(s) responsible for the killing activity was dependent on growth temperature and that both unstable and stable substances with killing activity were present in the CFCSs. We found that the complete inhibition of serovar Typhimurium SL1344 growth results from a pH-lowering effect.

Effect of pH, Acidulant, Time, and Temperature on the Growth and Survival of Listeria monocytogenes

1989 ◽  
Vol 52 (8) ◽  
pp. 571-573 ◽  
Author(s):  
KENT M. SORRELLS ◽  
DAVIN C. ENIGL ◽  
JOHN R. HATFIELD
Keyword(s):  
Antimicrobial Activity ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Citric Acid ◽  
Hydrochloric Acid ◽  
Malic Acid ◽  
Incubation Temperature ◽  
Growth And Survival ◽  
Ph Values

The effect of different acids, pH, incubation time, and incubation temperature on the growth and survival of four strains of Listeria monocytogenes in tryptic soy broth was compared. Hydrochloric acid (HCl), acetic acid (AA), lactic acid (LA), malic acid (MA), and citric acid (CA) were used to acidify tryptic soy broth to pH values 4.4, 4.6, 4.8, 5.0, and 5.2 pH. Incubation times were 1, 3, 7, 14, and 28 d at 10, 25, and 35°C. The inhibition of L. monocytogenes in the presence of high acidity appears to be a function of acid and incubation temperature. Based on equal pH values, the antimicrobial activity is AA &gt; LA &gt; CA ≥ MA &gt; HCl at all incubation times and temperatures. When based on equal molar concentration, the activity appeared to be CA ≥ MA &gt; LA ≥ AA &gt; HCl at 35 and 25°C, and MA &gt; CA &gt; AA ≥ LA &gt; HCl at 10°C. Greatest antimicrobial activity occurred at 35°C. Greatest survival occurred at 10°C and greatest growth occurred at 25°C. Final pH of the medium was as low as 3.8 in HCl at 28 d. All strains grew well at pH values lower than the minimum previously reported (5.5–5.6).

scholarly journals Cronobacter sakazakii and Microbiological Profile of Infant Formulae and Some Dairy Products Consumed by Infants

2020 ◽  
Vol 8 (3) ◽  
Author(s):  
Ibrahim Hassan Amer ◽  
Mohamed Ahmed Hassan Mansour ◽  
Eman Nabil Abdelfatah ◽  
Rowyda Mohamed Yousry Elshazely
Keyword(s):  
Dairy Products ◽  
Cronobacter Sakazakii ◽  
Microbiological Profile ◽  
Infant Formulae

scholarly journals AVALIAÇÃO DO EFEITO PROBIÓTICO DE Lactobacillus rhamnosus V5 CONTRA SALMONELLA ENTERICA sorovariedade Typhimurium.

2019 ◽  
pp. 231-240
Author(s):  
Carina Terumi Tsuruda ◽  
Patrícia Canteri De Souza ◽  
Erick Kenji Nishio ◽  
Ricardo Sérgio Couto de Almeida ◽  
Luciano Aparecido Panagio ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Lactobacillus Rhamnosus

scholarly journals Caco-2 Invasion by Cronobacter sakazakii and Salmonella enterica Exposed to Drying and Heat Treatments in Dried State in Milk Powder

2017 ◽  
Vol 8 ◽  
Author(s):  
Emilie Lang ◽  
Stéphane Guyot ◽  
Pablo Alvarez-Martin ◽  
Jean-Marie Perrier-Cornet ◽  
Patrick Gervais
Keyword(s):  
Salmonella Enterica ◽  
Milk Powder ◽  
Heat Treatments ◽  
Cronobacter Sakazakii

Inoculum preparation conditions influence adherence of Salmonella enterica serovars on red leaf lettuce (Lactuca sativa)

2021 ◽  
Author(s):  
Anne Nathalie Reid ◽  
Courtney R Conklin ◽  
Kimberly R Beaton ◽  
Nora M Donahue ◽  
Emily N Jackson ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Contact Time ◽  
Incubation Temperature ◽  
Plant Interactions ◽  
Pooled Data ◽  
Preparation Conditions ◽  
Plant Environment ◽  
Inoculum Preparation ◽  
Leaf Lettuce

Salmonella enterica has been increasingly linked to outbreaks involving consumption of fresh produce. While several studies have identified genes whose products are involved in mediating S. enterica -plant interactions, the use of varying experimental approaches, serovars and plant types have generated variable and conflicting data. The purpose of this study was to determine whether conditions under which inocula are prepared for in vitro plant interaction studies influence the outcome of these studies. Seven S. enterica serovars were grown in media of differing salinity and physical state, and incubated at either 25 or 37°C. These cultures were then used to inoculate red leaf lettuce and adherent microbes were subsequently recovered. While all serovars were influenced by inoculum preparation conditions, some showed greater variation than others. Analysis of pooled serovar data revealed that inocula prepared from either plates or biphasic cultures showed higher levels of interaction with red leaf lettuce than those prepared from broth cultures. Furthermore, incubation at 37°C enhanced adherence after 30s or 5d of contact time, while adherence levels after 1h of contact time were increased in low-salt media.  Broth-grown inocula were highly influenced by medium salinity and incubation temperature, while plate- and biphasic-grown inocula were only minimally affected. Therefore, inocula prepared from bacteria grown on plates or in biphasic culture would be most suitable for studies aiming to evaluate strategies to interfere with plant- S. enterica interactions. However, pooled data mask serovar-specific responses, and care should be taken to extrapolate these findings to individual serovars. The previous association of a serovar with outbreaks involving leafy greens did not correlate with levels of interaction with red leaf lettuce, suggesting that the occurrence of these serovars in/on these commodities does not reflect their fitness in the plant environment.

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