Susceptibility Of Lactic Acid Bacteria Research Articles

Antibiotic Susceptibility of Lactic Acid Bacteria Isolated From Cow, Goat, Donkey, Buffalo, Sheep, Camel and Human Milk

Breast milk is a very important factor in regulating gastrointestinal function, improving the immune system and preventing acute illnesses (e.g. acute otitis media), especially during breastfeeding. Breast milk allows beneficial bacteria such as bifidobacteria and lactobacillus species to colonise the newborn intestin*e instead of potential enteropathogenic bacteria such as streptococci and escherichia coli. The aim of the study was to compare the antibiotic resistance of Lactic acid bacteria members isolated from different milk samples. Six milk samples were collected from each of seven different milk sources (donkey, goat, cow, buffalo, sheep, camel and human). The MRS and M-17 medium were used with the double layer sandwich method for isolation of LAB members selected from typic colonies, gram-positive, catalase-negative used in the study. The isolated 42 LAB species were determined antibiotic susceptibility with 9 standart antibiotic discs such as tetracycline, penicillin, kanamycin, streptomycin, rifampin, gentamicin, chloramphenicol, teicoplanin, ciprofloxacin by agar disc diffusion assay test. The 18 LAB isolate were resistant to penicillin, 16 isolate to kanamycin, 14 isolate to gentamicin. LAB isolates such as H1, H4, H5 from Human milk and LAB isolate such as D1 from donkey milk was considered as MDR isolates because they were resistant to at least four of the tested drugs. Among the milks, sheep, camel, buffalo and goat milks were found to be more sensitive to antibiotics on average in the group.

Rapid identification and quantification of the antibiotic susceptibility of lactic acid bacteria using surface enhanced Raman spectroscopy

SERS was used to discriminate and quantify the antibiotic susceptibility of lactic acid bacteria at the early period of treatment.

Identification and antimicrobial susceptibility of lactic acid bacteria from fecal samples of indigenous and commercial pigs

Identification and antimicrobial susceptibility of lactic acid bacteria from fecal samples of indigenous and commercial pigs

Susceptibility of lactic acid bacteria, bifidobacteria and other bacteria of intestinal origin to chemotherapeutic agents

Chemotherapy is a cornerstone of cancer treatment but it can have serious side effects, such as intestinal mucositis. This work reports the susceptibility/resistance profiles of 34 species of lactic acid bacteria (LAB), bifidobacteria and other intestinal bacteria from different collections to various chemotherapeutic agents (CAs) currently used in cancer treatments in an attempt to identify microorganisms that could prevent or treat mucositis symptoms. The highest concentrations of the CAs tested were equal to or higher than those reached in plasma during anticancer treatments. All 34 species proved to be resistant at the highest concentrations assayed [minimum inhibitory concentrations (MICs) > 128 µg/mL] to capecitabine, cyclophosphamide, docetaxel, erlotinib, gefitinib, irinotecan and paclitaxel. For doxorubicin, 5-fluorouracil, gemcitabine and, especially, afatinib and pemetrexed, interspecies variation in the MIC was observed. In further work to assess the interspecies and intraspecies variability, MICs of the CAs pemetrexed and afatinib were determined for 32 strains belonging to four Bifidobacterium spp. of intestinal origin. For pemetrexed, a bimodal MIC curve was obtained (modes <2–8 µg/mL and >256 µg/mL), whilst a normal unimodal curve was obtained for afatinib (mode 128 µg/mL). Altogether, these results suggest that the majority of CAs should not, by themselves, perturb the microbial populations of the gut microbiota (but considering that they could be transformed in vivo into more toxic compounds). However, LAB and bifidobacteria, which are key players in the intestinal microbial balance of the healthy state, might be particularly inhibited by CAs such as gemcitabine or doxorubicin.

Antimicrobial susceptibility of lactic acid bacteria isolated from human and food-producing animal feces in Khon Kaen Province, Thailand

The aim of this study was to investigate the susceptibility of 93 Lactobacillus strains to seven antimicrobial agents, i.e., penicillin G, amoxicillin-clavulanic acid, vancomycin, tetracycline, streptomycin, ciprofloxacin, and sulfamethoxazole-trimethoprim, by disk diffusion test. The Lactobacillus strains were isolated from fecal samples taken from 90 healthy, food-producing animals (fattening pigs, free-grazing ducks, and beef cattle) and 30 healthy human subjects (1- to 6-year-olds) in Khon Kaen. The minimum inhibitory concentration (MIC) values of tetracycline and ciprofloxacin against all strains were determined using the E-test. All 93 Lactobacillus isolates were identified at the species level using 16S rRNA gene sequencing. The most common species of Lactobacillus isolated from fattening pigs, free-grazing ducks, beef cattle, and humans were L. reuteri (30%), L. salivarius (46.7%), L. acetotolerans (20%), and L. gasseri (33.3%), respectively. A total of 83 Lactobacillus strains were resistant to the examined antibiotics. Some strains were resistant to two to six types of antibiotics. More than 50% of Lactobacillus species were intrinsically resistant to vancomycin, streptomycin, ciprofloxacin, and sulfamethoxazole-trimethoprim. The prevalence of acquired resistance to tetracycline was observed for Lactobacillus isolates from fattening pigs, humans, free-grazing ducks, and beef cattle at 92.3, 85.7, 77.8, and 68.4%, respectively. These results demonstrate the impact of antibiotic use in human and veterinary medicine on antibiotic treatment efficacy and may support the spread of transferable antibiotic resistant genes to other bacteria via the food chain.

Functional Properties (Acid and Bile Tolerance) and Antibiotic Susceptibility of Lactic Acid Bacteria Isolated from Newborn Calves for the Design of a Probiotic Product

Diarrhea in young calves in dairy farms is one of the main causes of economic losses, morbidity and mortality. The use of probiotic products as feed additives or complements is a novel alternative for the prevention of intestinal syndromes. In order to include beneficial bacteria in the design of a probiotic product, their functional and safety characteristics must be studied.

Assessment of the susceptibility of lactic acid bacteria to biocides

Biocides are antimicrobial compounds that are widely used in the food industry and medical environments. In this study, we determined the Minimum Inhibitory Concentrations (MICs) by the microdilution method of four different biocides for a large collection of LAB of different origins. The tested isolates belong to 11 species of the Lactobacillus genus and to Streptococcus thermophilus, Streptococcus salivarius and Lactococcus garvieae. The results obtained in this study indicate that low susceptibilities to benzalkonium chloride (BC), triclosan (Tr), chlorhexidine (Ch), and sodium hypochlorite (SH) are not frequent among LAB. Moreover, no systematic co-tolerance between two or more tested biocides was found; that is, strains displaying high MIC values and thus low sensitivity to one of the biocides did not show higher MIC values for the other biocides.

Antimicrobial susceptibility of lactic acid bacteria isolated from Sombor cheese

Extensive literature data pointed out that some lactic acid bacteria (LABs), the predominant microbiota in fermented dairy products, may serve as reservoirs of antibiotic resistance genes potentially transferable to human pathogens. Hence, there is a growing interest in the possible role of Las vectors of antibiotic resistance determinants. This paper reports the susceptibility patterns of a number of Lspecies (belonging to the genera Lactococcus, Lactobacillus, and Enterococcus) isolated from different batches of autochthonous Sombor cheese, traditionally made without the addition of starter cultures, and currently proposed as a candidate for PDO/PGI designation. The experimental work was performed to select strains that do not contain antibiotic resistance genes among those with desirable technological characteristics such as rapid acidification, proteolysis, ability to metabolise citrate and form aromogenic compounds. In addition, the results of these screening procedures could also indicate the types and degrees of antimicrobial resistance already present among the Lcommunity of Sombor cheese, which according to their geographically restricted areas of production, specific manufacturing process and characteristic aroma and appearance, represent a distinct ecological niche.

Antimicrobial susceptibility testing of lactic acid bacteria and bifidobacteria by broth microdilution method and Etest

We applied two methods of broth microdilution and Etest for measuring minimal inhibition concentration (MIC) of lactic acid bacteria and bifidobacteria for 15 antimicrobial agents to compare the feasibility, reproducibility, and equivalence of the two methods. Both methods were originally described by the European projects PROSAFE and ACE-ART. In 84% combinations of strains and antimicrobial agents MIC differences between the two methods were within one Log 2 dilution. In the case of rifampicin the difference between the two methods was more than ten fold. We further determined MICs of 70 strains (14 strains of Lactobacillus delbrueckii ssp. bulgaricus, 16 strains of Lactococcus lactis, 30 strains of Streptococcus thermophilus, and 10 strains of Bifidobacterium longum) by the broth microdilution method. In most cases, MIC distributions were uni-modal and within 5 Log 2 dilutions except for the MIC distribution of L. lactis to the aminoglycoside group which was broader. These data are a good basis for improving knowledge of antimicrobial susceptibility of lactic acid bacteria and bifidobacteria, and can be used to revise tentative epidemiological cut-off values.

Identification and Antimicrobial Susceptibility of Lactic Acid Bacteria from Retail Fermented Foods

One important safety criterion of using lactic acid bacteria (LAB) in food applications is to ensure that they do not carry transferable antimicrobial resistance (AR) determinants. In this study, 63 LAB belonging to six genera, Streptococcus, Lactobacillus, Lactococcus, Enterococcus, Leuconostoc, and Pediococcus, were recovered from 28 retail fermented food products in Maryland, identified to species with 16S–23S rRNA spacer PCRs, and characterized for antimicrobial susceptibility against eight antimicrobials. Besides intrinsic resistance to ciprofloxacin or vancomycin in some lactobacilli, tetracycline resistance was observed in two Streptococcus thermophilus isolates from one cheese and one sour cream sample and was associated with the presence of a nonconjugative tet(S) gene. The results indicated a low level of AR among naturally occurring and starter LAB cultures in fermented dairy and meat products in the United States; therefore, the probability for foodborne LAB to serve as reservoirs of AR is low. Further studies involving a larger sample size are needed to assess the potential risk of AR gene transfer from LAB in fermented food products.

Antimicrobial Susceptibility of Lactic Acid Bacteria Isolated From Native Chicken Feces

Antimicrobial Susceptibility of Lactic Acid Bacteria Isolated From Native Chicken Feces

Antimicrobial susceptibility of lactic acid bacteria isolated from a cheese environment

In the production of the Spanish traditional blue-veined Cabrales cheese, lactic acid bacteria strains free of antibiotic resistance that have a transferrable capacity are necessary as components of a specific starter. To select for these bacteria, the minimum inhibitory concentration (MIC) of 12 antibiotics and 2 mixtures (containing beta-lactamase inhibitor and penicillin) were determined by microbroth and agar dilution techniques in 146 strains belonging to the genera Lactococcus, Enterococcus, Lactobacillus, and Leuconostoc. The antibiotic-resistance profiles of Lactococcus and Enterococcus species were different from those of Lactobacillus and Leuconostoc, but clear genus- or species-associated patterns were not observed. Cefoxitin and metronidazole were not effective against bacteria of these genera. The MICs of beta-lactam antibiotics for lactobacilli and leuconostoc isolates were higher than those for lactococci and enterococci, but no strain was clinically resistant. All lactobacilli and leuconostoc isolates were resistant to high levels of vancomycin, a type of resistance not seen among the tested members of the genera Lactococcus and Enterococcus. The majority of the observed resistance appeared to be either intrinsic or nonspecific, although some strains of Lactococcus lactis, Enterococcus spp., and Lactobacillus spp. were resistant to antibiotics, such as chloramphenicol, erythromycin, clindamycin, or tetracycline.