Isolation and Identification of Lactic Acid Bacteria from Cow Milk and Milk Products.

Lactic acid bacteria (LAB) have long been consumed by people in several fermented foods such as dairy products. A study was conducted on lactating dairy cows to isolate and characterize LAB from dairy products found in and around Bahir-Dar city, North Western Ethiopia. Milk and milk products were randomly collected from dairy farms, milk vending shops, individual households, and supermarkets for bacteriological investigations. A total of sixteen samples were taken from different sources and cultured on different selective media: de Man, Rogosa, and Sharpe (MRS) agar for Lactobacillus spp.; M17 agar for Lactococcus spp.; Rogasa SL agar for Streptococci spp.; and MRS supplemented with cysteine (0.5%) for Bifidobacteria spp. Different laboratory techniques were implemented for LAB isolation and identification. A total of 41 bacterial isolates were grouped under five different genera of LAB and Bifidobacteria spp. were identified based on the growth morphology on the selective media, growth at a different temperature, gas production from glucose, carbohydrate fermentation, and other biochemical tests. LAB genera such as Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, Streptococcus, and Bifidobacterium spp. were isolated and identified from raw milk, cheese, and yogurt. Based on the current study, the majority of the LAB (24.38%) was isolated from cheese and yogurt. Among these, Lactobacillus, Lactococcus (21.94%), Streptococcus (19.51%), Leuconostoc (14.64%), Bifidobacteria (12.19%), and Pediococcus (7.31%) spp. were also identified from these products. Furthermore, based on the bacterial load count and different identification methodologies, our study revealed that Lactobacillus spp. were the dominant LAB isolated from milk and milk products. As a result, since there are few studies on the isolation and identification of lactic acid bacteria from dairy products in Ethiopia, more research studies are needed to complete the identification and characterization to species level and their possible role as probiotics.

Dynamic changes of total acid and bacterial communities during the traditional fermentation of Hong Qu glutinous rice wine

Background: Hong Qu glutinous rice wine (HQGRW) is brewed under non-aseptic fermentation conditions, so it usually has a relatively high total acid content. The aim of this study was to investigate the dynamics of the bacterial communities and total acid during the fermentation of HQGRW and elucidate the correlation between total acid and bacterial communities. Results: The results showed that the period of rapid acid increase during fermentation occurred at the early stage of fermentation. There was a negative response between total acid increase and the rate of increase in alcohol during the early fermentation stage. Bacterial community analysis using high-throughput sequencing technology was found that the dominant bacterial communities changed during the traditional fermentation of HQGRW. Both principal component analysis (PCA) and hierarchical clustering analysis revealed that there was a great difference between the bacterial communities of Hong Qu starter and those identified during the fermentation process. Furthermore, the key bacteria likely to be associated with total acid were identified by Spearman's correlation analysis. Lactobacillus, unclassified Lactobacillaceae, and Pediococcus were found, which can make significant contributions to the total acid development (| r| N 0.6 with FDR adjusted P b 0.05), establishing that these bacteria can associate closely with the total acid of rice wine. Conclusions: This was the first study to investigate the correlation between bacterial communities and total acid during the fermentation of HQGRW. These findings may be helpful in the development of a set of fermentation techniques for controlling total acid.

Isolation, characterization and identification of antigenotoxic and anticancerous indigenous probiotics and their prophylactic potential in experimental colon carcinogenesis.

Colorectal cancer, the third most commonly diagnosed cancer, is a lifestyle disease where diet and gut microbiome contribute intricately in its initiation and progression. Prophylactic bio-interventions mainly probiotics offer an alternate approach towards reducing or delaying its progression. Therefore, the present study was designed wherein a robust protocol for the isolation, characterization, and identification of indigenous probiotics having antigenotoxic and anticancerous activity was followed along with their prophylactic potential assessment in early experimental colorectal carcinogenesis. Among forty-six isolated lactic acid bacterial strains, only three were selected on the basis of antigenotoxicity against N,N-Dimethyl dihydrazine dihydrochloride and 4-Nitroquinoline 1-oxide and probiotic attributes. All three selected probiotic strains exhibited anticancerous potential as is evident by the reduced Aberrant Crypt Foci, reduced fecal pH, enhanced fecal lactic acid bacteria and altered fecal enzymes (ß-glucuronidase, nitroreductase, ß-glucosidase) that modulated gut microbiota and microenvironment resulting into restored histoarchitecture of the colon. The results are a clear indicator of the prophylactic potential of selected indigenous probiotics which may be used as an alternative prophylactic biological therapy against colon carcinogenesis particularly in highly susceptible individuals.

Extracellular Proteolytic Activity and Amino Acid Production by Lactic Acid Bacteria Isolated from Malaysian Foods.

Amino acids (AAs) are vital elements for growth, reproduction, and maintenance of organisms. Current technology uses genetically engineered microorganisms for AAs production, which has urged the search for a safer food-grade AA producer strain. The extracellular proteolytic activities of lactic acid bacteria (LAB) can be a vital tool to hydrolyze extracellular protein molecules into free AAs, thereby exhibiting great potential for functional AA production. In this study, eight LAB isolated from Malaysian foods were determined for their extracellular proteolytic activities and their capability of producing AAs. All studied LAB exhibited versatile extracellular proteolytic activities from acidic to alkaline pH conditions. In comparison, Pediococcus pentosaceus UP-2 exhibited the highest ability to produce 15 AAs extracellularly, including aspartate, lysine, methionine, threonine, isoleucine, glutamate, proline, alanine, valine, leucine, tryptophan, tyrosine, serine, glycine, and cystine, followed by Pediococcus pentosaceus UL-2, Pediococcus acidilactici UB-6, and Pediococcus acidilactici UP-1 with 11 to 12 different AAs production detected extracellularly. Pediococcus pentosaceus UL-6 demonstrated the highest increment of proline production at 24 h of incubation. However, Pediococcus acidilactici UL-3 and Lactobacillus plantarum I-UL4 exhibited the greatest requirement for AA. The results of this study showed that different LAB possess different extracellular proteolytic activities and potentials as extracellular AA producers.

Monitoring of wheat lactic acid bacteria from the field until the first step of dough fermentation.

The present work was carried out to retrieve the origin of lactic acid bacteria (LAB) in sourdough. To this purpose, wheat LAB were monitored from ear harvest until the first step of fermentation for sourdough development. The influence of the geographical area and variety on LAB species/strain composition was also determined. The ears of four Triticum durum varieties (Duilio, Iride, Saragolla and Simeto) were collected from several fields located within the Palermo province (Sicily, Italy) and microbiologically investigated. In order to trace the transfer of LAB during the consecutive steps of manipulation, ears were transformed aseptically and, after threshing, milling and fermentation, samples of kernels, semolinas and doughs, respectively, were analysed. LAB were not found to dominate the microbial communities of the raw materials. In general, kernels harboured lower levels of microorganisms than ears and ears than semolinas. Several samples showing no development of LAB colonies acidified the enrichment broth suggesting the presence of LAB below the detection limit. After fermentation, LAB loads increased consistently for all doughs, reaching levels of 7.0-7.5 Log CFU/g on M17. The values of pH (5.0) and TTA (5.6 mL NaOH/10 g of dough) indicated the occurrence of the acidification process for several doughs. LAB were phenotypically and genotypically differentiated by randomly amplified polymorphic DNA (RAPD)-PCR into eight groups including 51 strains belonging to the species Lactobacillus brevis, Lactobacillus coryniformis, Lactobacillus plantarum, Lactococcus lactis, Lactococcus garvieae, Enterococcus casseliflavus, Enterococcus faecium, Leuconostoc citreum, and Pediococcus pentosaceus. Lactobacilli constituted a minority the LAB community, while lactococci represented more than 50% of strains. Lower LAB complexity was found on kernels, while a richer biodiversity was observed in semolinas and fermented doughs. For broader microbiota characterisation in doughs before fermentation, the 16S rRNA gene fragment profiling was conducted on the unfermented doughs using MiSeq Illumina. LAB group was represented by Enterococcus, Lactococcus and members of Leuconostocaceae family whose relative abundances differed according to both geographical area and variety of wheat. The culture-independent approach confirmed that pediococci and lactobacilli constituted low abundance members of the semolina LAB microbiota and that although some strains may pass from wheat ear to fermented doughs, most are likely to come from other sources.

Probiotic properties of Pediococcus strains isolated from jeotgals, salted and fermented Korean sea-food.

Three Pediococcus pentosaceus strains were isolated from jeotgals, salted and fermented Korean sea-foods, and their probiotic potentials were examined. After 2 h exposure to pH 3.0, P. pentosaceus F66 survived with the survival ratio of 32.6% followed by P. pentosaceus D56 (17.2%) and P. pentosaceus A24 (7.5%). P. pentosaceus F66 also survived better (26.6%) than P. pentosaceus A24 (13.7%) and P. pentosaceus D56 (5.8%) after 2 h exposure to 0.3% bile salts. Three strains grew slowly on MRS broth with 15% NaCl (w/v), reaching the OD600 values of 0.4-0.8 in 36 h. They adhered to Caco-2 cells (10.9-13.9 CFU/cell) with similar degree of adherence of a positive control, Lactobacillus rhamnosus GG (12.8 ± 0.5 CFU/cell). Three strains possess some desirable enzyme activities such as ß-galactosidase, α-glucosidase, ß-glucosidase, and N-acetyl-ß-glucosidase. From these results, P. pentosaceus F66 seems qualified as a probiotic and can be utilized for fermented foods including jeotgals.

Novel dextran from Pediococcus pentosaceus CRAG3 isolated from fermented cucumber with anti-cancer properties.

The porous branched dextran of molecular mass 2.93 × 10(5) Da with 50% overall yield (4.5mg/ml) was produced from Pediococcus pentosaceus CRAG3 (GenBank ID: JX679020), a novel isolate from fermented cucumber. It contained glucose monomers linked through 75% α-(1,6) linkage with 25% (α-1,3) branching as displayed by spectroscopic analysis. The peak analysis showed α-(1,3) branching after every five glucose units of main chain. In vitro cytotoxicity analysis of dextran displayed anti-cancer activity against cervical cancer (HeLa) and colon cancer (HT29) cell lines opening new horizons in its pharmaceutical applications. Dextran showed enhanced growth of macrophage lines revealing its biocompatible nature.

A description of the lactic acid bacteria microbiota associated with the production of traditional fermented vegetables in Vietnam.

An important part of the daily nourishment in Vietnam constitutes of fermented vegetables. Bacteria and especially lactic acid bacteria play a central role in the production of many fermented vegetables. The current study was conducted to investigate the diversity of native lactic acid bacteria (LAB) populations in 'dua muoi' (mustard and beet fermentation) and 'ca muoi' (eggplant fermentation), three types of popular traditional fermented vegetables of Vietnamese origin. To this end a polyphasic approach combining matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and pheS gene sequence analysis was used. In addition, denaturing gradient gel electrophoresis was performed as a culture-independent method to complement the observed culturable diversity data. A total of 881 LAB isolates were recovered from 21 different samples. Predominant LAB associated with 'dua muoi' and 'ca muoi' were identified as Lactobacillus fermentum (56.6%), Lactobacillus pentosus (24.4%) and Lactobacillus plantarum (17.1%). Less abundant species were Pediococcus pentosaceus (1.0%) and Lactobacillus brevis (0.5%). Species present less than 0.1% included Lactobacillus paracasei, Lactobacillus pantheris and Pediococcus acidilactici. In contrast to fermented mustard and beet with the highest prevalence of L. fermentum, the species most recovered from fermented eggplant samples was L. pentosus. In addition, an important degree of genetic variability within the different predominant species was observed and strain dependency correlating with the type of fermented vegetable or location of production could be demonstrated using multivariate statistics. This research gives an extensive and detailed inventory of the LAB diversity associated with the production of diverse Vietnamese fermented vegetables and demonstrates the influence of type of raw material and/or production location and conditions on this diversity.

Spherical lactic acid bacteria activate plasmacytoid dendritic cells immunomodulatory function via TLR9-dependent crosstalk with myeloid dendritic cells.

Plasmacytoid dendritic cells (pDC) are a specialized sensor of viral and bacterial nucleic acids and a major producer of IFN-α that promotes host defense by priming both innate and acquired immune responses. Although synthetic Toll-like receptor (TLR) ligands, pathogenic bacteria and viruses activate pDC, there is limited investigation of non-pathogenic microbiota that are in wide industrial dietary use, such as lactic acid bacteria (LAB). In this study, we screened for LAB strains, which induce pDC activation and IFN-α production using murine bone marrow (BM)-derived Flt-3L induced dendritic cell culture. Microbial strains with such activity on pDC were absent in a diversity of bacillary strains, but were observed in certain spherical species (Lactococcus, Leuconostoc, Streptococcus and Pediococcus), which was correlated with their capacity for uptake by pDC. Detailed study of Lactococcus lactis subsp. lactis JCM5805 and JCM20101 revealed that the major type I and type III interferons were induced (IFN-α, -ß, and λ). IFN-α induction was TLR9 and MyD88-dependent; a slight impairment was also observed in TLR4(-/-) cells. While these responses occurred with purified pDC, IFN-α production was synergistic upon co-culture with myeloid dendritic cells (mDC), an interaction that required direct mDC-pDC contact. L. lactis strains also stimulated expression of immunoregulatory receptors on pDC (ICOS-L and PD-L1), and accordingly augmented pDC induction of CD4(+)CD25(+)FoxP3(+) Treg compared to the Lactobacillus strain. Oral administration of L. lactis JCM5805 induced significant activation of pDC resident in the intestinal draining mesenteric lymph nodes, but not in a remote lymphoid site (spleen). Taken together, certain non-pathogenic spherical LAB in wide dietary use has potent and diverse immunomodulatory effects on pDC potentially relevant to anti-viral immunity and chronic inflammatory disease.

Differential adaptation of human gut microbiota to bariatric surgery-induced weight loss: links with metabolic and low-grade inflammation markers.

OBJECTIVE: Obesity alters gut microbiota ecology and associates with low-grade inflammation in humans. Roux-en-Y gastric bypass (RYGB) surgery is one of the most efficient procedures for the treatment of morbid obesity resulting in drastic weight loss and improvement of metabolic and inflammatory status. We analyzed the impact of RYGB on the modifications of gut microbiota and examined links with adaptations associated with this procedure. RESEARCH DESIGN AND METHODS: Gut microbiota was profiled from fecal samples by real-time quantitative PCR in 13 lean control subjects and in 30 obese individuals (with seven type 2 diabetics) explored before (M0), 3 months (M3), and 6 months (M6) after RYGB. RESULTS: Four major findings are highlighted: 1) Bacteroides/Prevotella group was lower in obese subjects than in control subjects at M0 and increased at M3. It was negatively correlated with corpulence, but the correlation depended highly on caloric intake; 2) Escherichia coli species increased at M3 and inversely correlated with fat mass and leptin levels independently of changes in food intake; 3) lactic acid bacteria including Lactobacillus/Leuconostoc/Pediococcus group and Bifidobacterium genus decreased at M3; and 4) Faecalibacterium prausnitzii species was lower in subjects with diabetes and associated negatively with inflammatory markers at M0 and throughout the follow-up after surgery independently of changes in food intake. CONCLUSIONS: These results suggest that components of the dominant gut microbiota rapidly adapt in a starvation-like situation induced by RYGB while the F. prausnitzii species is directly linked to the reduction in low-grade inflammation state in obesity and diabetes independently of calorie intake.

Resolution of persistent Pediococcus bacteremia with daptomycin treatment: case report and review of the literature.

A case of bacteremia caused by Pediococcus acidilactici occurring in a patient with metastatic adenocarcinoma of the gallbladder is described. The bacteremia persisted despite an antimicrobial regimen of vancomycin, ciprofloxacin, metronidazole, and caspofungin. Within 36 h of switching the vancomycin to daptomycin (6 mg/kg per day), the bacteremia resolved and the patient improved clinically. Previous reports of human pediococcal infection are also reviewed.

Antagonistic activity of spent culture supernatants of lactic acid bacteria against Helicobacter pylori growth and infection in human gastric epithelial AGS cells.

We investigated the bactericidal activity and exclusion effect of 10 strains of lactic acid bacteria (LAB) isolated from different commercial food products and infant feces against Helicobacter pylori (H. pylori) in human gastric epithelial AGS cells. Antagonistic activity of spent culture supernatants (SCS) from LAB (LAB-SCS) was tested, and the content of organic acids in SCS was analyzed with high-performance liquid chromatography (HPLC). In addition, the bactericidal activities of LAB-SCS were estimated by a time-kill assay and by measuring the exclusion effect of LAB-SCS against H. pylori in AGS cells. The results showed that SCS from certain strains with higher concentrations of organic acids dramatically decreased the viability of H. pylori. We also proved that the organic acids could inhibit H. pylori adhesion and invasion of AGS cells. Furthermore, the concentration and speciation of organic acids in SCS after fermentation of LAB are important factors in the inhibition of H. pylori infection. In addition, the in vitro methods used in this study might provide for the rapid screening of potential probiotics with anti-H. pylori activity in the dairy industry.

Isolation and characterization of acid-sensitive mutants of Pediococcus acidilactici.

Acid-sensitive mutants of Pediococcus acidilactici BCC 9545, a starter culture of the Thai fermented pork sausage nham, were isolated as spontaneous neomycin resistant mutants. The mutants generally produced less acid and acidified the culture media less than the parent strain in a 72 h culturing period. Interestingly, the ATPase activities of the mutants did not differ considerably from that of the parent strain in acidic conditions. It was also found that the internal pH values of the mutant strains were somewhat lower in neutral environment, while at pH 5.0 their internal pHs were significantly lower compared to the parent's. Inhibiting the H(+)-ATPase activities in energized cells by N,N'-dicyclohexyl carbodiimide also revealed that protons were leaking from the mutants at neutral pH, which increased under acidic conditions. In contrast, the parent strain exhibited a smaller proton leak and only under acidic conditions. The membrane fatty acid analysis of the mutants indicated that under acidic conditions the mutants had a significantly smaller major unsaturated/saturated fatty acids ratio ((C(18:1)+C(18:3n6))/(C(16:0)+C(18:0))) compared to the parent strain's membrane. Taken together, these observations suggest there is a reasonable possibility that the membrane fatty acid profile differences in the mutants resulted in their acid-sensitivity.

Transport of glycerol by Pediococcus pentosaceus isolated from wine.

Pediococcus pentosaceus N(5)p is a strain isolated from wine that uses glycerol as its sole carbon source, mainly via the glycerol kinase pathway. The transport of glycerol was investigated in resting cells of this strain. Glycerol uptake followed a Michaelis-Menten relationship with an observed apparent K(m) of 33 microM and a V(max) of 2.5 nmol/min/mg of cell protein. The transport system was specific for glycerol, which was present in the cells grown either on glycerol or glucose suggesting its constitutive nature. The presence of uptake when resting cells were treated with HgCl(2) and the absence of counterflow indicate that facilitated diffusion is not involved in glycerol transport. On the other hand, glycerol uptake was inhibited by the metabolic poisons that affect ATP availability by acting on either electron transport or ATPase activity, and by the proton-conducting uncouplers without any effect on glycerol kinase activity. The restoration of glycerol uptake in de-energized cells by the addition of glucose and low concentration of cyanide-m-chlorophenyl hydrazone was achieved. These results, the first in the genus Pediococcus, provide evidence for an energy-dependent uptake of glycerol that involves the proton motive force directly or coupled with ATP synthesis.

Diversity of predominant lactic acid bacteria associated with cocoa fermentation in Nigeria.

The fermentation of cocoa relies on a complex succession of bacteria and filamentous fungi, all of which can have an impact on cocoa flavor. So far, few investigations have focused on the diversity of lactic acid bacteria involved in cocoa fermentation, and many earlier investigations did not rely on polyphasic taxonomical approaches, which take both phenotypic and genotypic characterization techniques into account. In our study, we characterized predominant lactic acid bacteria from cocoa fermentations in Nigeria, using a combination of phenotypic tests, repetitive extragenic palindromic PCR, and sequencing of the 16S rRNA gene of representative strains for accurate species identification. Thus, of a total of 193 lactic acid bacteria (LAB) strains isolated from common media used to cultivate LAB, 40 (20.7%) were heterofermentative and consisted of either L. brevis or L. fermentum strains. The majority of the isolates were homofermentative rods (110 strains; 57% of isolates) which were characterized as L. plantarum strains. The homofermentative cocci consisted predominantly of 35 (18.1% of isolates) Pediococcus acidilactici strains. Thus, the LAB populations derived from these media in this study were accurately described. This can contribute to the further assessment of the effect of common LAB strains on the flavor characteristics of fermenting cocoa in further studies.

Exploring the use of natural antimicrobial agents and pulsed electric fields to control spoilage bacteria during a beer production process / Exploración del uso de agentes antimicrobianos naturales y de campos eléctricos pulsantes para el control de bacterias contaminantes durante el proceso de elaboración de cerveza

Different natural antimicrobials affected viability of bacterial contaminants isolated at critical steps during a beer production process. In the presence of 1 mg/ml chitosan and 0.3 mg/ml hops, the viability of Escherichia coli in an all malt barley extract wort could be reduced to 0.7 and 0.1% respectively after 2 hour- incubation at 4 °C. The addition of 0.0002 mg/ml nisin, 0.1 mg/ml chitosan or 0.3 mg/ml hops, selectively inhibited growth of Pediococcus sp. in more than 10,000 times with respect to brewing yeast in a mixed culture. In the presence of 0.1mg ml chitosan in beer, no viable cells of the thermoresistant strain Bacillus megaterium were detected. Nisin, chitosan and hops increased microbiological stability during storage of a local commercial beer inoculated with Lactobacillus plantarum or Pediococcus sp. isolated from wort. Pulsed Electric Field (PEF) (8 kV/cm, 3 pulses) application enhanced antibacterial activity of nisin and hops but not that of chitosan. The results herein obtained suggest that the use of these antimicrobial compounds in isolation or in combination with PEF would be effective to control bacterial contamination during beer production and storage.

Diferentes antimicrobianos naturales disminuyeron la viabilidad de bacterias contaminantes aisladas en etapas críticas del proceso de producción de cerveza. En un extracto de malta, el agregado de 1 mg/ml de quitosano y de 0,3 mg ml de lúpulo permitió reducir la viabilidad de Escherichia coli a 0,7 y 0,1%, respectivamente, al cabo de 2 horas de incubación a 4 °C. El agregado de 0,0002 mg/ml de nisina, 0,1 mg/ml de quitosano o de 0,3 mg/ml de lúpulo inhibió selectivamente (10.000 veces más) el crecimiento de Pediococcus sp. respecto de la levadura de cerveza en un cultivo mixto. El agregado de 0,1 mg/ml de quitosano permitió disminuir la viabilidad de una cepa bacteriana termorresistente, Bacillus megaterium, hasta niveles no detectables. Por otra parte, el agregado de nisina, quitosano y lúpulo aumentó la estabilidad microbiológica durante el almacenamiento de cervezas inoculadas con Lactobacillus plantarum y Pediococcus sp. aislados de mosto de cerveza. La aplicación de campos eléctricos pulsantes (CEP) (3 pulsos de 8kV/cm) aumentó el efecto antimicrobiano de la nisina y del lúpulo, pero no el del quitosano. Los resultados obtenidos indicarían que el uso de antimicrobianos naturales en forma individual o en combinación con CEP puede constituir un procedimiento efectivo para el control de la contaminación bacteriana durante el proceso de elaboración y almacenamiento de la cerveza.

Identification of subdominant sourdough lactic acid bacteria and their evolution during laboratory-scale fermentations.

Presumptive lactic acid bacterial cocci were found in six sourdoughs (out of 20) from the Abruzzo region (central Italy) and subjected to phenotypic and genotypic characterization. A total of 21 isolates, recognized as seven strains by randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR) typing, were identified by a polyphasic approach, consisting of 16S rRNA gene sequencing, multiplex PCR assays and physiological features, as Enterococcus faecium and Pediococcus pentosaceus. Four strains belonging to those species and previously isolated from wheat kernels were inoculated in sterile flour to verify their capacity to grow in sourdough environment. Doughs with several dual bacterial combinations, including Lactobacillus sanfranciscensis, were propagated for 11 days and pH measurements and bacterial counts were carried out.

Enumeration and identification of pediococci in powder-based products using selective media and rapid PFGE.

In this study, pediococci selective medium (PSM) was evaluated for the enumeration of Pediococcus acidilactici and Pediococcus pentosaceus from probiotic animal feed and silage inoculants. PSM is based on the complex basal medium MRS supplemented with cysteine hydrochloride, novobiocin, vancomycin, and nystatin. No significant change in electivity was observed when pediococci where recovered from culture or powder-based products following incubation at 37 degrees C under anaerobic conditions for 24 h. The medium was suitable for the enumeration of pediococci in samples also containing bacilli, bifidobacteria, enterococci, lactobacilli, lactococci, propionibacteria, streptococci, and yeast components. However, to inhibit Lactobacillus plantarum and Lactobacillus casei, ampicillin was added and the revised medium, termed PSM+A, was also considered to be suitably elective for pediococci recovered from powder. In addition, a rapid PFGE protocol is presented, which allows Pediococcus species and strain verification from colonies in less than 3 days.

Isolation and characterization of anti-Salmonella lactic acid bacteria from the porcine gastrointestinal tract.

AIMS: To identify lactic acid bacteria (LAB) of porcine intestinal origin with anti-Salmonella activity. METHODS AND RESULTS: Samples were obtained from pig faeces and caeca and screened for the presence of anti-Salmonella LAB. The 11 most promising isolates were identified as belonging to the genera Lactobacillus and Pediococcus. The LAB exhibited large variation in their ability to survive in simulated gastric juice at pH 1.85. While Lactobacillus johnsonii species survived at levels of 80% for up to 30 min, Lactobacillus pentosus species declined to <0.001% in that time. All isolates tolerated porcine bile at a concentration of 0.3% (w/v), with some isolates capable of growth in the presence of up to 5% (w/v) bile. The ability of the LAB isolates to prevent Salmonella invasion of intestinal epithelial HT-29 cells varied, with reductions of between 30% (Lact. pentosus) and 80% (Lactobacillus murinus spp.) observed. CONCLUSIONS: LAB of porcine origin were observed to survive simulated passage through the GIT and inhibit growth of Salmonella and its invasion of the intestinal epithelium. SIGNIFICANCE AND IMPACT OF THE STUDY: The data demonstrate that some porcine intestinal LAB isolates may offer potential as probiotics for the reduction of Salmonella carriage in pigs.

Direct polymerase chain reaction detection of ropy Pediococcus damnosus strains in wine.

AIMS: Glucan-producing strains of Pediococcus damnosus are considered as spoilage micro-organisms because synthesis of glucan leads to an unacceptable viscosity of wine. In this report, we present a polymerase chain reaction (PCR) procedure to detect the presence of such strains in wines. METHODS AND RESULTS: We developed a direct DNA isolation method from the wine microflora using polyvinylpyrrolidone in order to decrease the polyphenolic concentration. The sequence of the plasmid involved in glucan production allowed the design of a primer pair usable for a specific and sensitive PCR procedure, leading to the amplification of a 563-bp fragment. CONCLUSION: The detection limit in wine was 102 cfu ml-1. The detection sensitivity could be increased by using a second primer pair in nested PCR assays. SIGNIFICANCE AND IMPACT OF THE STUDY: The method proved to be efficient for the early and sensitive detection of ropy Ped. damnosus strains during wine-making. Time-consuming culture and colony isolation steps are no longer needed.