scholarly journals Profiling and antibiotic resistance of lactic acid bacteria isolated from commercial aMasi samples

2020 ◽  
Author(s):  
◽  
Yovani Pillay
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Food Safety ◽  
Lactic Acid Bacteria ◽  
South African ◽  
Bacterial Population ◽  
Principal Component ◽  
Antibiotic Resistant ◽  
Food Grade ◽  
Resistant Genes

aMasi is traditionally fermented milk that constitutes part of the South African heritage and is regarded as a supplementary staple food. Its inclusion into the South African Food Based Dietary Guidelines has led to the encouraged consumption of this product. Given the fact that aMasi is a rich source of lactic acid bacteria (LAB), such bacteria are of economic importance to the food, feed and pharmaceutical industries. The main concern regarding food safety is ability to acquire and disseminate antibiotic-resistant genes. Although LAB bility of resistance genes to human and animal opportunistic and pathogenic bacteria which could make treatment of bacterial infections more complex to treat in the future. Numerous reports globally, have documented antibiotic resistance among LAB isolated from commercial dairy and pharmaceutical products over the last decade. Therefore, the aim of this study was to determine if LAB isolated from commercial aMasi samples harbour antibiotic-resistant genes. To achieve this aim, the total bacterial population and LAB population of 10 aMasi samples were surveyed using culture-dependent techniques and the proportional prevalence of LAB to the total bacterial population were determined by using a 100% stacked-column. In all 10 samples, LAB was the predominating population ranging from 87.44% to 99.77%. A total of 30 LAB isolates were characterised after isolation and sequencing of 16S rDNA of these isolates showed that LAB were Leuconostoc pseudomesenteroides and Leuconostoc mesenteroides with two isolates being identified as Lactococcus lactis CP028160.1. The relationship between the growth of LAB and selected physicochemical properties (pH, titratable acidity, water activity (aw), moisture content, fat content and estimation of reducing sugars (lactose)) were determined using principal component analysis (PCA) and classification and regression tree (CART) to illustrate the likelihood of LAB present in aMasi samples based on LAB count and pH. From the PCA results, approximately 75.25% of variances in the data were retained by the first three principal components (PCs). The first principal component (PC1) had accounted for the highest total variance of 33.16%. PC1 increased with an increase in lactic acid % and aw, whilst it negatively correlated with LAB count, moisture % and lactose (mg/25ml lactose·H2O). The results showed an increase in LAB count with an increase in moisture % and lactose (mg/25ml lactose·H2O) whilst, LAB count had decreased with an increase in lactic acid % and aw. Moreover, pH and fat % had no effect on PC1, high LAB counts were observed for samples 6 and 7 whist low LAB counts were observed for samples 9 and 10. On the other hand, PC2 had accounted for approximately 27.53% of the total variance. PC2 increased with an increase in fat % and lactose (mg/25ml lactose·H2O), whilst it negatively correlated with LAB count and pH. It was observed that the growth of LAB had increased with an increase in pH, whilst it decreased with an increase in fat % and lactose (mg/25ml lactose·H2O). Moreover, lactic acid %, aw and moisture % had no effect on PC2. High LAB counts were observed for samples 7 and 8 and low LAB counts were observed for samples 2 and 4. Nine out of the 30 LAB isolates were selected due to these isolates having a different GenBank Accession number and were subjected to antibiotic susceptibility testing using the disc diffusion method against a total of 11 antibiotics. Most of the LAB isolates exhibited multiple resistance towards some of the most commonly used antibiotics as well as last-resort antibiotics. All the isolates showed high levels of resistance towards vancomycin, colistin sulphate, fosfomycin and pipemidic acid except for Lactococcus lactis CP028160.1 which was susceptible to vancomycin. All isolates were susceptible to tetracycline and erythromycin whilst eight out of nine isolates were susceptible to chloramphenicol with seven out of nine isolates being susceptible to ampicillin. Furthermore, the isolates had displayed intermediate resistance mainly towards kanamycin and streptomycin. The present study showed that multiple antibiotic resistance is prevalent in different species of starter culture strains, which may pose a food safety concern. LAB that exhibit phenotypic resistance to antibiotics should also be evaluated on a molecular level to monitor their resistance. The presence of such a variety of expressed AR genes in probiotic isolates is a worrying trend. The impact of the interactions of these bacteria with pathogenic strains and their transfer of these AR genes is yet to be assessed. Furthermore, antibiotic sensitivity is an important criterion in the safety assessment for the evaluation of food-grade and potential food-grade LAB.

scholarly journals МОЛОЧНОКИСЛЫЕ БАКТЕРИИ ПРОТИВ АНТИБИОТИКОРЕЗИСТЕНТНЫХ ПАТОГЕНОВ

2021 ◽  
Author(s):  
A.Zh. AlybaYeva ◽  
M.G. Saubenova ◽  
E.A. Oleinikova ◽  
A.V. CHIZHAYEVA ◽  
A.A. Aitzhanova ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
21St Century ◽  
Bacterial Resistance ◽  
Antimicrobial Properties ◽  
Antibiotic Resistant ◽  
Resistance To Antibiotics ◽  
Microbial Strains

Antibiotic resistance of microorganisms is one of the greatest challenges of the 21st century. Many of the previously effective antibiotics are no longer applicable due to the widespread prevalence of resistant microbial strains. The ubiquity of resistant organisms is revealed in a number of articles. Bacterial resistance to antibiotics is very actively researched, measured and monitored at the epidemiological level. Particular attention is paid to the study of the antimicrobial properties of lactic acid bacteria, since they have various advantages as a means of combating antibiotic-resistant pathogens. Устойчивость микроорганизмов к антибиотикам - одна из самых серьезных проблем XXI века. Многие из ранее эффективных антибиотиков больше не применимы из-за широкого распространения штаммов резистентных микробов. Вездесущность устойчивых организмов раскрывается в ряде статей. Устойчивость бактерий к антибиотикам очень активно исследуется, измеряется и отслеживается на эпидемиологическом уровне. Особенное внимание уделяется исследованию антимикробных свойств молочнокислых бактерий, так как они обладают различными преимуществами в качестве средств борьбы с антибиотикорезистентнымы патогенами.

scholarly journals The evolution of lactic acid bacteria community during the development of mature sourdough

2009 ◽  
pp. 111-122
Author(s):  
Tanja Zugic-Petrovic ◽  
Natasa Jokovic ◽  
Dragisa Savic
Keyword(s):  
Principal Component Analysis ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Population ◽  
Principal Component ◽  
Bacterial Count ◽  
Phenotypic Characterization ◽  
Statistical Techniques ◽  
Total Bacterial Count ◽  
Genus Lactobacillus

In order to follow the composition and changes in lactic acid bacteria (LAB) population of rye flour sourdough that was continuously propagated by a repeated inoculation, sixty-two strains of LAB were isolated and characterized. The LAB were the only bacteria detected, both at the end of the second propagation step and in the stage of mature sourdough (after two weeks of continuous daily refreshment). The stable ecological system in rye sourdough could be established from the second propagation step onward. The predominant genera of LAB during the development of sourdough were lactobacilli, which were grouped in eight clusters. Heterofermentative lactobacilli were in majority in both propagation step two and a mature sourdough participating 56% and 70% of total bacterial count, respectively. The identification based on a phenotypic characterization that was carried out by using a set of 36 tests, showed that the lactobacilli contained in the two sourdough steps did not clearly belong to any known species of the genus Lactobacillus. In addition, the structure of the bacterial population were monitored by two statistical techniques (Hierachical Cluster Analysis and Principal Component Analysis), being applied to phenotypical characteristics of the isolates.

scholarly journals Suitability Analysis of 17 Probiotic Type Strains of Lactic Acid Bacteria as Starter for Kimchi Fermentation

Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1435
Author(s):  
Hee Seo ◽  
Jae-Han Bae ◽  
Gayun Kim ◽  
Seul-Ah Kim ◽  
Byung Hee Ryu ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Growth Rates ◽  
Principal Component ◽  
Fermented Foods ◽  
Suitability Analysis ◽  
Moderate Growth ◽  
Health Promoting ◽  
Highly Correlated ◽  
Type Strains

The use of probiotic starters can improve the sensory and health-promoting properties of fermented foods. This study aimed to evaluate the suitability of probiotic lactic acid bacteria (LAB) as a starter for kimchi fermentation. Seventeen probiotic type strains were tested for their growth rates, volatile aroma compounds, metabolites, and sensory characteristics of kimchi, and their characteristics were compared to those of Leuconostoc (Le.) mesenteroides DRC 1506, a commercial kimchi starter. Among the tested strains, Limosilactobacillus fermentum, Limosilactobacillus reuteri, Lacticaseibacillus rhamnosus, Lacticaseibacillus paracasei, and Ligilactobacillus salivarius exhibited high or moderate growth rates in simulated kimchi juice (SKJ) at 37 °C and 15 °C. When these five strains were inoculated in kimchi and metabolite profiles were analyzed during fermentation using GC/MS and 1H-NMR, data from the principal component analysis (PCA) showed that L. fermentum and L. reuteri were highly correlated with Le. mesenteroides in concentrations of sugar, mannitol, lactate, acetate, and total volatile compounds. Sensory test results also indicated that these three strains showed similar sensory preferences. In conclusion, L. fermentum and L. reuteri can be considered potential candidates as probiotic starters or cocultures to develop health-promoting kimchi products.

scholarly journals Comparison of the Fecal Microbiota of Horses with Intestinal Disease and Their Healthy Counterparts

2021 ◽  
Vol 8 (6) ◽  
pp. 113
Author(s):  
Taemook Park ◽  
Heetae Cheong ◽  
Jungho Yoon ◽  
Ahram Kim ◽  
Youngmin Yun ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Metabolic Disorders ◽  
Bacterial Population ◽  
Fecal Microbiota ◽  
Intestinal Disease ◽  
Fecal Samples ◽  
Gut Dysbiosis ◽  
Rrna Sequencing ◽  
Small Intestinal

(1) Background: The intestinal microbiota plays an essential role in maintaining the host’s health. Dysbiosis of the equine hindgut microbiota can alter the fermentation patterns and cause metabolic disorders. (2) Methods: This study compared the fecal microbiota composition of horses with intestinal disease and their healthy counterparts living in Korea using 16S rRNA sequencing from fecal samples. A total of 52 fecal samples were collected and divided into three groups: horses with large intestinal disease (n = 20), horses with small intestinal disease (n = 8), and healthy horses (n = 24). (3) Results: Horses with intestinal diseases had fewer species and a less diverse bacterial population than healthy horses. Lactic acid bacteria, Lachnospiraceae, and Lactobacillaceae were overgrown in horses with large intestinal colic. The Firmicutes to Bacteroidetes ratio (F/B), which is a relevant marker of gut dysbiosis, was 1.94, 2.37, and 1.74 for horses with large intestinal colic, small intestinal colic, and healthy horses, respectively. (4) Conclusions: The overgrowth of two lactic acid bacteria families, Lachnospiraceae and Lactobacillaceae, led to a decrease in hindgut pH that interfered with normal fermentation, which might cause large intestinal colic. The overgrowth of Streptococcus also led to a decrease in pH in the hindgut, which suppressed the proliferation of the methanogen and reduced methanogenesis in horses with small intestinal colic.

scholarly journals Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts

2012 ◽  
Vol 95 (9) ◽  
pp. 4775-4783 ◽  
Author(s):  
N. Zhou ◽  
J.X. Zhang ◽  
M.T. Fan ◽  
J. Wang ◽  
G. Guo ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria

Food-grade lactic acid bacteria and probiotics as a potential protective tool against erythrotoxic dietary xenobiotics

2021 ◽  
Author(s):  
Paúl F. Cuevas-González ◽  
Audry Peredo-Lovillo ◽  
Cecilia Castro-López ◽  
Belinda Vallejo-Cordoba ◽  
Aarón F. González-Córdova ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Food Grade

Lactic Acid Bacteria as a Tool for Enhancing Food Safety by Removal of Dietary Toxins

2004 ◽  
Author(s):  
Hani El-Nezami ◽  
Seppo Salminen ◽  
Eeva Salminen ◽  
Carolyn Haskard ◽  
Hannu Mykkanen
Keyword(s):  
Lactic Acid ◽  
Food Safety ◽  
Lactic Acid Bacteria ◽  
Dietary Toxins

scholarly journals Antimicrobial Susceptibility of Lactic Acid Bacteria Strains of Potential Use as Feed Additives - The Basic Safety and Usefulness Criterion

2021 ◽  
Vol 8 ◽  
Author(s):  
Ilona Stefańska ◽  
Ewelina Kwiecień ◽  
Katarzyna Jóźwiak-Piasecka ◽  
Monika Garbowska ◽  
Marian Binek ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Resistance Genes ◽  
Pathogenic Bacteria ◽  
Feed Additives ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Safety Criterion ◽  
Phenotypic Resistance

The spread of resistance to antibiotics is a major health concern worldwide due to the increasing rate of isolation of multidrug resistant pathogens hampering the treatment of infections. The food chain has been recognized as one of the key routes of antibiotic resistant bacteria transmission between animals and humans. Considering that lactic acid bacteria (LAB) could act as a reservoir of transferable antibiotic resistance genes, LAB strains intended to be used as feed additives should be monitored for their safety. Sixty-five LAB strains which might be potentially used as probiotic feed additives or silage inoculants, were assessed for susceptibility to eight clinically relevant antimicrobials by a minimum inhibitory concentration determination. Among antimicrobial resistant strains, a prevalence of selected genes associated with the acquired resistance was investigated. Nineteen LAB strains displayed phenotypic resistance to one antibiotic, and 15 strains were resistant to more than one of the tested antibiotics. The resistance to aminoglycosides and tetracyclines were the most prevalent and were found in 37 and 26% of the studied strains, respectively. Phenotypic resistance to other antimicrobials was found in single strains. Determinants related to resistance phenotypes were detected in 15 strains as follows, the aph(3″)-IIIa gene in 9 strains, the lnu(A) gene in three strains, the str(A)-str(B), erm(B), msr(C), and tet(M) genes in two strains and the tet(K) gene in one strain. The nucleotide sequences of the detected genes revealed homology to the sequences of the transmissible resistance genes found in lactic acid bacteria as well as pathogenic bacteria. Our study highlights that LAB may be a reservoir of antimicrobial resistance determinants, thus, the first and key step in considering the usefulness of LAB strains as feed additives should be an assessment of their antibiotic resistance. This safety criterion should always precede more complex studies, such as an assessment of adaptability of a strain or its beneficial effect on a host. These results would help in the selection of the best LAB strains for use as feed additives. Importantly, presented data can be useful for revising the current microbiological cut-off values within the genus Lactobacillus and Pediococcus.

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