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The aim of this study was to evaluate the effect of ampicillin, an organic acid-based feed additive and a synbiotic preparation on the prevalence of antibiotic-resistant E. coli in the ceca of broilers. A total of 2000 broiler chickens (Ross 708) were randomly assigned to 5 groups with 8 replicates. The negative control group was the only group that was not subjected to avian pathogenic E. coli challenge, while all the other 4 groups received a multi-resistant E. coli strain that was resistant to ampicillin, cephalexin, and nalidixic acid as an oral challenge. The second group served as a challenge control, and the third group received the antibiotic ampicillin via water for 5 d. The fourth group received a feed additive based on organic acids and cinnamaldehyde, and the fifth group received a synbiotic preparation via feed and water. On day 17 and 38 of the trial, cecal samples from 3 birds from each of the 40 pens were obtained, and the E. coli counts and abundances of antibiotic-resistant E. coli were determined. Oral challenge with an avian pathogenic E. coli strain did not influence the performance, and there was no significant difference in growth performance between groups. The total E. coli count was lower (P < 0.05) in the group supplemented with the synbiotic than in the challenge control group on day 38 of the trial. Administration of an antibiotic for 5 d led to a significant increase in the abundance of E. coli strains resistant to ampicillin, amoxicillin-clavulanic acid, cefoxitin, and ceftriaxone. There was no increase in the abundance of antibiotic-resistant E. coli observed in the groups that received feed supplemented with an organic acid/cinnamaldehyde-based feed additive or a synbiotic. Moreover, the effects of the tested feed additives on the prevalence of resistant E. coli are demonstrated by the lower ceftriaxone minimal inhibitory concentration values for this group than for the antibiotic group. Additionally, the synbiotic group exhibited lower ceftriaxone minimal inhibitory concentration values than the antibiotic group.

Cronobacter spp. are opportunistic human pathogens that cause serious diseases in neonates and immunocompromised people. Owing to their biofilm formation on various surfaces, both their detection and their removal from production plants constitute a major challenge. In this study, food samples were randomly collected in Austria and examined for the presence of Cronobacter spp. Presumptive isolates were identified by a polyphasic approach. Five percent of the samples were positive for C. sakazakii and 2.4% for C. dublinensis. Individual growth of the isolates was characterized based on lag time, growth rate, and generation time. During an incubation period of 6 to 72 h, biofilm formation of 11 selected isolates was quantified under model conditions by a crystal violet staining assay with 96-well plates with different carbon sources (lactose, glucose, maltose, sucrose, and sodium acetate) and NaCl levels and under variable temperature and pH conditions. Biofilm formation was more pronounced at lactose concentrations between 0.25 and 3% compared with 5% lactose, which lead to thinner layers. C. sakazakii isolate C7, isolated from infant milk powder, was the strongest biofilm producer at 10 mM Mg2+ and 5 mM Mn2+, 0.5% sodium acetate, at pH levels between 7 and 9 at 37°C for 24 h. C. sakazakii strain C6 isolated from a plant air filter was identified as a moderate biofilm former and C. sakazakii strain DSM 4485, a clinical isolate, as a weak biofilm former. Based on PCR detection, genes bcsA, bcsB, and bcsG encoding for cellulose could be identified as markers for biofilm formation. Isolates carrying bcsA and bcsB showed significantly stronger biofilm formation than isolates without these genes ( P < 0.05), in strong correlation with the results obtained in the crystal violet assay. Further investigations using confocal laser scanning microscopy revealed that extracellular polymeric substances and glycocalyx secretions were the dominating components of the biofilms and that the viable fraction of bacteria in the biofilm decreased over time.

Food fermentation technologies have developed through years of experience rather than scientific findings. Therefore, many small-scale manufacturers are unwilling to accept changes and to modify fermentation processes. Still, traditional fermented foods have had an essential role in human nutrition for thousands of years. A wide range of diverse cereals, legumes, vegetables, fruits, fish, seafood, and meat are used as raw materials for the production of these fermented foods by back-slopping (a process where material from a previous successful batch is added to facilitate the initiation of a new batch) or naturally occurring microorganisms. Various microorganisms that influence the quality, safety, sensory properties, acceptability, and consistency of these products are present. Lactic acid bacteria with their beneficial characteristics are generally a significant contributor. Identification and profiling of microorganisms in fermented foods are of particular interest. But so far such information has not been explored in detail for some fermented products from the lower Mekong subregion. Improving the safety, quality, and acceptability of fermented foods, while reducing their production costs and maintaining their authenticity and uniqueness, is important. This can be achieved through starter culture application and greater attention to food safety, such as HACCP approaches. Recent scientific advances have led to the development of defined microbial starters, leading to the transfer of artisanal food production to more controlled and industrialized fermentation. The aim of this review is to determine the gaps in the knowledge of traditional fermented foods of the lower Mekong subregion and to present current information on the diversity of involved microorganisms. These data will be helpful for defining future strategies toward the sustainable production of safe fermented foods particularly those from southeast Asia.

The quantification of nitrate and nitrite in molasses is an emerging requirement for the sugar industry. The establishment of a validated analytical methodology is necessary to comply with the EU-guidelines on maximum permissible levels currently under discussion. In the present study, validation of an anion exchange chromatographic method to determine nitrate and nitrite in molasses was performed determining key validation parameters via several stages of an interlaboratory comparison for the first time. Since a stable, homogeneous sample material was necessary for establishing quantitative accuracy, a nitrite-spiked molasses material was prepared and evaluated independently across two laboratories in a parallel study. This preliminary study revealed that quantification of nitrate and nitrite content in molasses could be achieved with excellent precision under repeatability conditions of measurement (1.21% RSD for nitrate; 1.26% RSD for nitrite) in independent laboratories but requires preservation of samples at −20 °C for long-term (>several days) storage prior the analysis. A subsequent stage involving five different participating laboratories was then undertaken to evaluate anion exchange chromatography with conductivity detection for this application within a round robin study. The first phase focused on the analysis of nitrite-spiked molasses to optimize the individual analytical practices of laboratories and to elaborate a harmonized sample preparation protocol. In the second phase the participating laboratories analyzed seven molasses samples with different pH-value, dry substance, factory origin, with nitrate levels ranging from 2931 mg/kg – 6436 mg/kg and nitrite levels ranging from 25.3 mg/kg – 109 mg/kg. The determination of precision of reproducibility conditions of measurement revealed average relative interlaboratory standard deviations of 2.5% for nitrate and of 13% for nitrite. The present study clearly demonstrates the necessity of harmonization and standardization regarding measurement and data evaluation procedures applied for controlling nitrate and nitrite in molasses.

The deterioration of fresh food by spoilage microorganisms remains a significant problem even though a diversity of preservation approaches has been proposed. The consumer's choice is demanding for chemical and antimicrobial-free products, which has prompted the development of natural alternatives to retard food spoilage. This study was performed to evaluate the effect of the combination of essential oils (EOs) (orange, tea tree, citronella grass and cinnamon) and enterocin KT2W2G against spoilage microorganisms isolated from the surface of spoiled banana (Musa ABB cv. Kluai “Namwa”) peel by using the agar well diffusion assay. Eighteen spoilage microorganisms (9 strains of bacteria and 9 strains of yeast) were selected as indicator strains. They were identified based on partial 16S rDNA and 18S rDNA gene sequencing for bacteria and yeast, respectively. Selected spoilage bacteria were identified as Lactococcus lactis subsp. lactis, Enterococcus faecalis, Klebsiella pneumonia, Klebsiella variicola and Serratia marcescens, whereas selected spoilage yeast were identified as Kodamaea ohmeri, Pichia aff. fermentans, Pichia kudriavzevii, Hanseniaspora opuntiae and Candida metapsilosis. The agar well diffusion assays resulted in cinnamon as being the most effective EO against selected spoilage indicator. The combination of cinnamon oil and enterocin KT2W2G at 6:4 ratios exhibited the best synergistic effect against selected spoilage microorganisms, whereas enterocin KT2W2G applied as single substance displayed no activity. The results obtained indicate that the combination of cinnamon oil with enterocin KT2W2G harbours the potential to be used as a natural biocontrol agent to improve food quality and to extend the shelf life of harvested bananas.

Clostridial contamination of raw milk causes late-blowing, a severe quality defect in cheese. Consequently, milk containing high numbers of cheese-damaging clostridial spores should not be used for the production of certain types of hard and semi-hard cheese. Currently, there is no officially standardised method available to monitor clostridial spore levels in milk, and major drawbacks like long analysis time, labour intensity, uncertainty of results and insufficient selectivity for clostridia exist for usually used conventional MPN (most probable number) techniques. Therefore, an optimised medium in combination with a semi-automated application for the enumeration of clostridia in milk was developed. The aim of this study was to evaluate this new methodology in comparison with a conventional method (using Bryant and Burkey broth) based on the analysis of 84 milk samples. Method inclusivity was further tested using pure clostridial cultures, and selectivity was assessed by molecular identification of isolates obtained from the new assay. The novel approach proved to be suitable for the detection of clostridia in both suppliers’ and processed milk, also indicating that it is superior in selectivity, sensitivity and analysis time compared to conventional techniques.

In cheese production, knowledge of clostridial spore levels in milk is crucial to avoid economic losses due to late-blowing, a characteristic quality defect observed especially in hard cheeses. However, no international standard method is available to quantify clostridial spores in milk. Since performance data on the currently applied enumeration methods have not been systematically investigated, in this study we assessed four routine media and most probable number (MPN) methods for the enumeration of cheese-damaging clostridia in milk. Among the four evaluated methods, statistically significant differences became evident, while moderate to optimal correlations were observed. Bacterial isolates from positive reactions were identified using molecular methods. All four methods assessed showed a severe lack of selectivity due to the incorporation of non-clostridial spore-formers in the counts produced. The results illustrate major drawbacks of currently used methods and stress the necessity for improving method selectivity, sensitivity and reliability before standardisation can be envisaged.

Lactic acid bacteria (LAB) from spontaneous rye sourdough were isolated, identified, and characterized by their growth, acidification rate, and carbohydrate metabolism. The isolated LAB were used for production of rye sourdough, and the influence of sourdough on mixed rye - wheat bread quality and acrylamide formation was evaluated. In addition, comparative studies by using acidification with L-(+)-lactic acid for mixed rye – wheat bread production were performed. Isolated LAB (P. acidilactici, L. plantarum, L. curvatus) demonstrated versatile carbohydrate metabolism, grown at 30 °C and 37 °C, and acidic tolerance. When the isolated strains were used for rye sourdough production, they showed good growth, acidification rates while excreting amylolytic and proteolytic enzymes. Rye sourdoughs delay bread staling, and there was a significant effect of type of dough acidification (with LAB or L-(+)-lactic acid) and the quantity of acidification agent used (5% or 15%) on most of the analyzed bread quality parameters. L. plantarum sourdough (added in the amount of 5% and 15%) decreased the acrylamide content in bread samples (p

Via butyric acid fermentation, clostridia – mainly Clostridium tyrobutyricum – are able to transform lactic acid into butyric acid, acetic acid and gas (H2 and CO2). The presence of clostridial endospores in milk may lead to severe quality defects in semi-hard and hard cheeses. As a consequence of butyric acid fermentation during ripening, cheeses tend to swell and develop undesired slits, irregular eyes and a rancid taste, thus resulting in high economic losses for producers. Several measures regarding stable, milking and feed hygiene have already been partly implemented to minimise the risk of raw milk contamination with clostridial endospores. Contamination, nevertheless, cannot be avoided completely. Moreover, some of the existing procedures to reduce the bacterial and endospore count in milk (e.g. bactofugation, addition of bacteriocins) are not always applicable or even prohibited for the production of certain cheese types. Therefore, cheese producers may benefit from integrating the determination of the initial count of clostridial endospores in milk into their quality control system of primary materials. This review discusses the role of butyric acid clostridia in the cheese processing environment and methods for the detection and enumeration of cheese-damaging clostridia in milk and cheese.

The fish gut microbiota contributes to digestion and can affect the nutrition, growth, reproduction, overall population dynamics and vulnerability of the host fish to disease; therefore, this microbial community is highly relevant for aquaculture practice. Recent advances in DNA sequencing technologies and bioinformatic analysis have allowed us to develop a broader understanding of the complex microbial communities associated with various habitats, including the fish gut microbiota. These recent advances have substantially improved our knowledge of bacterial community profiles in the fish intestinal microbiota in response to a variety of factors affecting the host, including variations in temperature, salinity, developmental stage, digestive physiology and feeding strategy. The goal of this review is to highlight the potential of next-generation sequencing platforms for analysing fish gut microbiota. Recent and promising results in this field are presented along with a focus on new perspectives and future research directions of fish gut microbial ecology.

In sourdough processing, lactic acid bacteria (LAB) and yeasts are responsible for the bread's unique characteristics. To evaluate the microbial ecology of traditional Austrian sourdoughs, 11 wheat and nine rye sourdoughs were examined. The colony counts of the LAB ranged from

Food packaging materials fundamentally contribute to food quality and safety, as they protect the packaged food against external influences. In this context, the determination of the hygiene status of the packaging material is of great importance. However, European legislation neither sets any microbiological criteria nor provides any approved standard for the microbiological testing of food packaging materials. Nevertheless, reliable routine control is essential for guaranteeing high hygienic quality of packagings. With the aim to achieve a maximum recovery rate at low contamination levels, an improved experimental design was developed for the enumeration of the total colony count, yeasts and molds and Enterobacteriaceae on the surface of roll stock packaging materials. For this purpose, two different types of paper laminates were selected and exemplarily used as objects of investigation. Moreover, the performance of different growth media was compared for each microbiological parameter. This approach was followed by method validation using a selection of quantitative reference materials of representative microorganisms, including resistant forms of microbes such as bacterial endospores and fungal spores.

A pig digestibility trial was conducted to investigate the effects of fermentation or extrusion of wheat bran included in a basal diet on coefficients of total tract apparent digestibility (CTTAD) regarding dry matter (DM), organic matter (OM), crude protein (CP), crude fiber (CF), ether extract (EE), starch, energy (GE), phosphorus (P) and calcium (Ca). In the experiment, 9 growing pigs were allocated to a 3 × 3 Latin square design to measure the CTTAD of the basal diet containing different modified wheat bran variants, and therefore to demonstrate relative differences in the CTTAD among the diets as a result of wheat bran modification. The wheat bran was used in native form (NWB), as fermented bran ensiled with Lactobacillus paracasei and Lactobacillus plantarum (FWB) and as extruded wheat bran (EWB). Wheat bran variants were included at 200 g kg −1 in a phosphorus deficient basal diet. The obtained results show that the CTTAD of DM was increased when feeding the diet with FWB (+2%, P P P P P P P P P P P

A B S T R A C T Objective: Lactobacilli have been found in the neovagina of very low numbers of transsexual women. We undertook this study to determine whether an orally administered preparation of four lactobacilli strains exerts some measurable effect on the neovaginal microflora of female transsexuals. Study design: 60 male to female transsexual women with penile linked neovagina were randomised into two groups. Women in the intervention group (n = 33) received oral probiotic capsules and women in the control group (n = 27) placebo in for 7 days. Swabs of the neovagina were taken before and after the therapy. Results: Comparing the first and second swabs, we observed a significant improvement of the Nugent score in the intervention group 16 (48.5%) vs. low improvement in control group 4 (14.8%) (p < 0.006). The neovaginal microflora was significantly enriched with lactobacilli after oral supplementation compared to placebo. In the intervention group, an increase by 10,000 600 colony forming units (CFU) of presumptive lactobacilli was observed, compared with an increase by 1600 100 CFU in the control group (p < 0.0001). When measured by real-time PCR (c/ml), lactobacilli increased by 1400 100 c/ml in the intervention group and 300 100 c/ml in the control group (p < 0.0001). Conclusion: There was an improvement of vaginal lactobacilli microflora after of oral supplementation with lactobacilli strains in transsexual women.

Biopreservation is a powerful and natural tool to extend shelf life and to enhance the safety of foods by applying naturally occurring microorganisms and/or their inherent antibacterial compounds of defined quality and at certain quantities. In this context, lactic acid bacteria (LAB) possess a major potential for use in biopreservation because most LAB are generally recognized as safe, and they naturally dominate the microflora of many foods. The antagonistic and inhibitory properties of LAB are due to different factors such as the competition for nutrients and the production of one or more antimicrobially active metabolites such as organic acids (prevailingly lactic and acetic acid), hydrogen peroxide, and antimicrobial peptides (bacteriocins). This review addresses various aspects related to the biological preservation of seafood and seafood products by LAB and their metabolites.

The antimicrobial spectrum and physico-chemical characteristics of bacteriocin like inhibitory substances produced by lactobacilli isolated from the intestinal flora of Sturgeon fish were determined in order to evaluate their inhibitory potential exerted against 42 food-borne and aquaculture-related bacterial pathogens as well as against food spoilage causing bacteria. In a first series a collection of 84 Lactobacillus strains previously isolated from Beluga (Huso huso) and Persian sturgeon (Acipenser persicus) were screened for their inhibitory activities and potential bacteriocin production against two indicator strains, Listeria monocytogenes ATCC 19115 and Salmonella enterica subsp. enterica serovar Typhimurium ATCC 14028. The isolates Lactobacillus casei AP8 and Lactobacillus plantarum H5 showed the highest activity and therefore were subjected to further examination to clarify the nature of the inhibitory effect. The physico-chemical properties of the harvested antimicrobial compounds were similar to those of bacteriocins of lactobacilli belonging to the group II with respect to molecular weight (5 and 3 kDa respectively), pronounced temperature stability (−20 °C to 120 °C), pH tolerance (3–12), chemical stability (SDS, EDTA, Tween 20, Tween 80) and sensitivity to proteolytic enzymes. Importantly, different food borne pathogens like Escherichia coli, Listeria spp., Salmonella spp., Staphylococcus aureus, Aeromonas hydrophila, Vibrio anguillarum, and Bacillus cereus were inhibited by cell-free supernatants of the strains selected. The broad inhibitory spectrum, the technological properties, especially the stability may lead to the assumption that the bacteriocins like inhibitory AP8 and H5 may be applied as biopreservative agents to control pathogens and spoiling bacteria in different food products. Furthermore their role as bioprotective agents in aquaculture systems is envisaged.

The BacT/ALERT 3D equipment was applied as a fast and sensitive method for the detection of Gram-negative re-contaminants in pasteurised dairy products, particularly drinking milk and cream. The iAST medium was modified and then applied to eleven certified reference strains and nine relevant wild-type isolates originating from a dairy plant. Gram-negative strains could be detected at low levels in pure culture and in combination with high numbers of Gram-positive bacteria as background microflora. Additional experiments with qualified reference material (Escherichia coli, Pseudomonas aeruginosa) showed that low levels of contamination of these bacteria were detectable within 1 and 1.5 days, respectively. The milk matrices exerted no relevant effect on the detectability of the Gram-negative re-contaminants tested. Based on the technique developed, a faster hygiene monitoring and enhanced approval of dairy product lots at the production site is enabled.

Various techniques have been used for tracing the transmission routes of Listeria species and for the assessment of hygiene standards in food processing plants. The potential of repetitive element sequence-based PCR (Rep-PCR) methods (GTG₅ and REPI + II) for the typing of Listeria isolates (n = 116), including Listeria monocytogenes (n = 46), was evaluated in a particular situation arising from the relocation of a company producing cold-smoked salmon. Pulsed-field gel electrophoresis (PFGE) using three restriction enzymes (ApaI, AscI, and SmaI) was used for comparison. Identical transmission scenarios among two companies could be identified by cluster analysis of L. monocytogenes isolates that were indistinguishable by both Rep-PCR and PFGE. The calculated diversity index (DI) indicates that Rep-PCR subtyping of Listeria species with primer sets GTG₅ and REPI + II has a lower discrimination power than does PFGE. When concatenated Rep-PCR cluster analysis was used, the DI increased from 0.934 (REPI + II) and 0.923 (GTG₅) to 0.956. The discrimination power of this method was similar to that of PFGE typing based on restriction enzyme Apa I (DI = 0.955). Listeria welshimeri may be useful as an indicator for monitoring smoked salmon processing environments. Rep-PCR meets the expectations of a reasonable, fast, and low-cost molecular subtyping method for the routine monitoring of Listeria species. The discriminatory power as characterized by the DI sufficiently quantifies the probability of unrelated isolates being characterized as different subtypes. Therefore, Rep-PCR typing based on two primer systems (GTG₅ and REPI + II) may be a useful tool for monitoring industrial hygiene.

Objective To investigate the hypothesis that the rectum may be an important reservoir for vaginal colonisation by Lactobacillus species. Study design We included 60 pregnant women aged 18–35 years and 80 postmenopausal women aged 55–65 years in this cross-sectional observational study. Participants had to be without clinical signs of vaginal infection and without hormone replacement therapy. Only women with normal vaginal microflora (Nugent scores 0–3) were included in the evaluation. The first oral, vaginal, and rectal smears were taken for the enumeration of lactobacilli by cultural methods and identification of dominating lactobacilli based on multiplex polymerase chain reaction (PCR). The second oral, vaginal, and rectal smears were taken for molecular lactobacilli profiling using PCR denaturing gradient gel electrophoresis (DGGE). Results 30 pregnant and 30 postmenopausal women were evaluated. On multiplex PCR, 99 colonies isolated from 30 pregnant women and 37 colonies isolated from 30 postmenopausal women were identified as being members of the genus Lactobacillus : 50% of pregnant and 33% of postmenopausal women had one or more Lactobacillus spp. recovered from their oral specimens. Around 80% of pregnant and 40% of postmenopausal women harboured one or more Lactobacillus spp. in the vagina and rectum. On PCR-DGGE, 80% of pregnant and 40% of postmenopausal women harboured the same lactobacilli isolates in both the vagina and rectum. Conclusion This study supports the hypothesis that the rectum may play an important role as a reservoir for some strains of lactobacilli that colonise the vagina.

Highlights ► Deoxynivalenol-3-glucoside (D3G) is hydrolyzed to deoxynivalenol during digestion. ► D3G is resistant to acids and enzymes expressed by humans. ► D3G is partly cleaved by cellulase and cellobiase. ► Several intestinal bacteria liberate deoxynivalenol from D3G. ► D3G is of toxicological relevance and should be monitored in food., Deoxynivalenol-3-β-d-glucoside (D3G), a plant phase II metabolite of the Fusarium mycotoxin deoxynivalenol (DON), occurs in naturally contaminated wheat, maize, oat, barley and products thereof. Although considered as a detoxification product in plants, the toxicity of this substance in mammals is currently unknown. A major concern is the possible hydrolysis of the D3G conjugate back to its toxic precursor mycotoxin DON during mammalian digestion. We used in vitro model systems to investigate the stability of D3G to acidic conditions, hydrolytic enzymes and intestinal bacteria, mimicking different stages of digestion. D3G was found resistant to 0.2 M hydrochloric acid for at least 24 h at 37 °C, suggesting that it will not be hydrolyzed in the stomach of mammals. While human cytosolic β-glucosidase also had no effect, fungal cellulase and cellobiase preparations could cleave a significant portion of D3G. Most importantly, several lactic acid bacteria such as Enterococcus durans, Enterococcus mundtii or Lactobacillus plantarum showed a high capability to hydrolyze D3G. Taken together these data indicate that D3G is of toxicological relevance and should be regarded as a masked mycotoxin.

The multifaceted properties of Listeria monocytogenes allow the microorganism to grow and multiply in various food matrices even under adverse conditions. Therefore methods are needed to detect and trace this pathogen along the entire food supply network. Analytical methods have to fulfill several needs and also should meet the requirements of governmental, scientific and industrial parties. Among these demands, the level of detection based on genus and/or species or even strain specific information is of high practical significance to the food manufacturer. Hence, the release of sufficiently resolved information should be integrated into risk analysis and elucidation of contamination routes. This review aims at providing a current overview of methods for detecting, isolating and subtyping L. monocytogenes in various matrices, taking into account recent studies indicating the different drawbacks and advantages of commonly applied methods.

Probiotic enterococci are frequently encountered as additives in animal nutrition, but no fast standardized methods for their unambiguous identification at strain level exist. Six polymerase chain reaction (PCR)-based methods previously described for similar tasks but other genera were evaluated concerning their suitability for the rapid, stringent and reliable identification of Enterococcus at strain level. The most appropriate method should facilitate the instant identification of isolates from animal feeds and should be applicable in routine quality control. Amplified ribosomal DNA analysis (ARDRA), internally transcribed spacer region (ITS)-PCR, randomly amplified polymorphic DNA (RAPD)-PCR, repetitive element sequence based (rep)-PCR, tRNA intergenic spacer PCR and 16S rRNA gene typing were investigated with 74 Enterococcus, mainly E. faecium, strains representing 11 species. RAPD-PCR proved superior by discriminating at the strain level. Depending on the enzyme, ARDRA yielded fingerprints specific for a species or even single strains. The remaining methods successfully identified enterococci at the genus level.

There is urgent need for having available suitable methods and data regarding the susceptibility levels of antibiotic resistant and sensitive strains of bifidobacteria. Based on a defined standard operation procedure, agar disc diffusion and broth microdilution were compared in order to evaluate the antimicrobial susceptibility profiles of 82 B. pseudolongum and 80 B. thermophilum strains mainly originating from the meat production chain. The methods that were assessed showed interpretable agreement within this study. The disc diffusion zone diameters are highly reproducible making the method a useful alternative to broth microdilution for antimicrobial susceptibility screening of bifidobacteria.

This paper reviews the methodology applied for the identification and characterisation of enterococci and covers phenotypic, genotypic and phylogenetic techniques. Although conventional phenotypic typing schemes are useful for rapid and simple identification of enterococcal species for routine applications, other methods like standardised sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE), multilocus enzyme electrophoresis (MLEE), antimicrobial susceptibility testing, serotyping, pyrolysis mass spectrometry (pyMS) and vibrational spectroscopic methods allow a more in-depth characterisation of enterococci. Many of the recently described enterococcal species exhibit deviations from hitherto so-called classical enterococci with regard to their phenotypical properties. Therefore, genotypic methods have to be used to clarify their possible assignment to the genus Enterococcus. In this review, special emphasis is given on recently developed polymerase chain reaction (PCR)-based typing methods such as random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), specific and random amplification (SARA) and modifications of PCR-ribotyping as well as pulsed-field gel electrophoresis (PFGE) and partial sequence analysis. The use of PCR and probes for genus and species identification of enterococci is also considered like the application of sequence data of conserved DNA regions (e.g., ribosomal ribonucleic acid (rRNA) genes) in the case of species identification.

In our previous experiment, the ten calves originated bifidobacterial strains were administered to calves and re-isolated. Fingerprinting techniques used in this study enabled us to distinguish the surviving and non-surviving strains. Only the species Bifidobacterium animalis ssp. animalis and Bifidobacterium longum ssp. suis were found to survive in the intestine.