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Morandi S, Silvetti T, Lopreiato V, Piccioli-Cappelli F, Trevisi E, Brasca M. Biodiversity and antibiotic resistance profile provide new evidence for a different origin of enterococci in bovine raw milk and feces. Food Microbiol 2024; 120:104492. [PMID: 38431334 DOI: 10.1016/j.fm.2024.104492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 01/25/2024] [Accepted: 02/14/2024] [Indexed: 03/05/2024]
Abstract
Enterococci are widely distributed in dairy sector. They are commensals of the gastrointestinal tract of animals, thus, via fecal contamination, could reach raw milk and dairy products. The aims of this study were: 1) to investigate the enterococcal diversity in cow feces and milk samples and 2) to evaluate the antibiotic resistance (AR) of dairy-related enterococci and their ability to transfer resistance genes. E. faecalis (59.9%), E. faecium (18.6%) and E. lactis (12.4%) were prevalent in milk, while E. faecium (84.2%) and E. hirae (15.0%) were dominant in bovine feces. RAPD-PCR highlighted a high number of Enterococcus biotypes (45 from milk and 37 from feces) and none of the milk strains exhibited genetic profiles similar to those of feces biotypes. A high percentage of enterococci isolated from milk (71%) were identified as multidrug resistant and resistance against streptomycin and tetracycline were widespread among milk strains while enterococci from feces were commonly resistant to linezolid and quinupristin/dalfopristin. Only E. faecalis strains were able to transfer horizontally the tetM gene to Lb. delbrueckii subsp. lactis. Our results indicated that Enterococcus biotypes from milk and bovine feces belong to different community and the ability of these microorganisms to transfer AR genes is strain-dependent.
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Affiliation(s)
- Stefano Morandi
- Institute of Sciences of Food Production (ISPA), Italian National Research Council, Milan, Italy.
| | - Tiziana Silvetti
- Institute of Sciences of Food Production (ISPA), Italian National Research Council, Milan, Italy
| | - Vincenzo Lopreiato
- Department of Veterinary Sciences, University of Messina, Viale Palatucci 13, Messina, 98168, Italy
| | - Fiorenzo Piccioli-Cappelli
- Department of Animal Sciences, Food and Nutrition (DIANA), Alimentari e Ambientali, Università Cattolica Del Sacro Cuore, Piacenza, 29122, Italy
| | - Erminio Trevisi
- Department of Animal Sciences, Food and Nutrition (DIANA), Alimentari e Ambientali, Università Cattolica Del Sacro Cuore, Piacenza, 29122, Italy
| | - Milena Brasca
- Institute of Sciences of Food Production (ISPA), Italian National Research Council, Milan, Italy
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Pandova M, Kizheva Y, Tsenova M, Rusinova M, Borisova T, Hristova P. Pathogenic Potential and Antibiotic Susceptibility: A Comprehensive Study of Enterococci from Different Ecological Settings. Pathogens 2023; 13:36. [PMID: 38251343 PMCID: PMC10818344 DOI: 10.3390/pathogens13010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/23/2024] Open
Abstract
The pathway and the lifestyle of known enterococcus species are too complicated. The aim of the present study is to trace the path of pathogenicity of enterococci isolated from seven habitats (Cornu aspersum intestine; Bulgarian yoghurt; goat and cow feta cheese-mature and young, respectively; Arabian street food-doner kebab; cow milk; and human breast milk) by comparing their pathogenic potential. In total, 72 enterococcal strains were isolated and identified by MALDI-TOF, sequencing, and PCR. Hemolytic and gelatinase activity were biochemically determined. PCR was carried out for detection of virulence factors (cylB, esp, gls24, nucl, psaA, agg, gelE, and ace) and antibiotic resistance (erm, ermB, blaZ, vanA, aphA, mefA, gyrA, catpIP501, and aac6'-aph2″). Phenotypic antibiotic resistance was assigned according to EUCAST. Eleven representatives of the genus Enterococcus were identified: E. mundtii, E. casseliflavus, E. gilvus, E. pseudoavium, E. pallens, E. malodoratus, E. devriesei, E. gallinarum, E. durans, E. faecium, and E. faecalis. Twenty-two strains expressed α-hemolysis. Thirteen strains had the cylB gene. Only two strains expressed α-hemolysis and possessed the cylB gene simultaneously. Positive amplification for gelE was found in 35% of the isolates, but phenotypic gelatinase activity was observed only in three strains. All isolates showed varying antibiotic resistance. Only E. faecalis BM15 showed multiple resistance (AMP-HLSR-RP). Correlation between genotypic and phenotypic macrolide resistance was revealed for two E. faecalis strains.
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Affiliation(s)
- Maria Pandova
- Department of General and Industrial Microbiology, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria; (M.P.); (M.T.); (P.H.)
| | - Yoana Kizheva
- Department of General and Industrial Microbiology, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria; (M.P.); (M.T.); (P.H.)
| | - Margarita Tsenova
- Department of General and Industrial Microbiology, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria; (M.P.); (M.T.); (P.H.)
| | - Mariya Rusinova
- Human Milk Bank Bulgaria, 1309 Sofia, Bulgaria; (M.R.); (T.B.)
| | | | - Petya Hristova
- Department of General and Industrial Microbiology, Faculty of Biology, Sofia University, 1164 Sofia, Bulgaria; (M.P.); (M.T.); (P.H.)
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3
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Bettera L, Levante A, Bancalari E, Bottari B, Gatti M. Lactic acid bacteria in cow raw milk for cheese production: Which and how many? Front Microbiol 2023; 13:1092224. [PMID: 36713157 PMCID: PMC9878191 DOI: 10.3389/fmicb.2022.1092224] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/28/2022] [Indexed: 01/15/2023] Open
Abstract
Lactic Acid Bacteria (LAB) exert a fundamental activity in cheese production, as starter LAB in curd acidification, or non-starter LAB (NSLAB) during ripening, in particular in flavor formation. NSLAB originate from the farm and dairy environment, becoming natural contaminants of raw milk where they are present in very low concentrations. Afterward, throughout the different cheesemaking processes, they withstand chemical and physical stresses becoming dominant in ripened cheeses. However, despite a great body of knowledge is available in the literature about NSLAB effect on cheese ripening, the investigations regarding their presence and abundance in raw milk are still poor. With the aim to answer the initial question: "which and how many LAB are present in cow raw milk used for cheese production?," this review has been divided in two main parts. The first one gives an overview of LAB presence in the complex microbiota of raw milk through the meta-analysis of recent taxonomic studies. In the second part, we present a collection of data about LAB quantification in raw milk by culture-dependent analysis, retrieved through a systematic review. Essentially, the revision of data obtained by plate counts on selective agar media showed an average higher concentration of coccoid LAB than lactobacilli, which was found to be consistent with meta-taxonomic analysis. The advantages of the impedometric technique applied to the quantification of LAB in raw milk were also briefly discussed with a focus on the statistical significance of the obtainable data. Furthermore, this approach was also found to be more accurate in highlighting that microorganisms other than LAB are the major component of raw milk. Nevertheless, the variability of the results observed in the studies based on the same counting methodology, highlights that different sampling methods, as well as the "history" of milk before analysis, are variables of great importance that need to be considered in raw milk analysis.
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Grenda A, Grenda T, Domaradzki P, Kwiatek K. Enterococci-Involvement in Pathogenesis and Therapeutic Potential in Cancer Treatment: A Mini-Review. Pathogens 2022; 11:pathogens11060687. [PMID: 35745541 PMCID: PMC9227201 DOI: 10.3390/pathogens11060687] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/10/2022] [Accepted: 06/11/2022] [Indexed: 12/04/2022] Open
Abstract
Enterococcus spp. are Gram-positive, heterogeneous lactic acid bacteria inhabiting various environments. Several species of Enterococci are considered to be able to stimulate the immune system and play an important role in intestinal homeostasis. Some Enterococci can be used as probiotics. Some strains of E. faecium are components of pharmaceutical products used to treat diarrhea, antibiotic-associated diarrhea, or irritable bowel syndrome (IBS). However, it has been proved that they are responsible for food contamination, and are sometimes undesirable from the point of view of food technology. Additionally, the virulence and multi-drug resistance of Enterococci potentially pose a risk of an epidemic, especially in hospital environments. Moreover, there are indications of their negative role in colon tumorigenesis; however, some nterococci are proved to support immunotherapy in cancer treatment. In general, it can be concluded that this group of microorganisms, despite its nature, has properties that can be used to support cancer treatment—both aggressive chemotherapy and cutting-edge therapy targeting immune checkpoints (IC).
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Affiliation(s)
- Anna Grenda
- Department of Pneumonology, Oncology and Allergology, Medical University in Lublin, Jaczewskiego 8, 20-950 Lublin, Poland
- Correspondence: ; Tel.: +48-81-724-42-93
| | - Tomasz Grenda
- Department of Hygiene of Animal Feeding Stuffs, National Veterinary Research Institute, Partyzantow 57, 24-100 Pulawy, Poland; (T.G.); (K.K.)
| | - Piotr Domaradzki
- Department of Commodity Science and Animal Raw Materials Processing, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland;
| | - Krzysztof Kwiatek
- Department of Hygiene of Animal Feeding Stuffs, National Veterinary Research Institute, Partyzantow 57, 24-100 Pulawy, Poland; (T.G.); (K.K.)
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The Many Faces of Enterococcus spp.-Commensal, Probiotic and Opportunistic Pathogen. Microorganisms 2021; 9:microorganisms9091900. [PMID: 34576796 PMCID: PMC8470767 DOI: 10.3390/microorganisms9091900] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 02/07/2023] Open
Abstract
Enterococcus spp. are Gram-positive, facultative, anaerobic cocci, which are found in the intestinal flora and, less frequently, in the vagina or mouth. Enterococcus faecalis and Enterococcus faecium are the most common species found in humans. As commensals, enterococci colonize the digestive system and participate in the modulation of the immune system in humans and animals. For many years reference enterococcal strains have been used as probiotic food additives or have been recommended as supplements for the treatment of intestinal dysbiosis and other conditions. The use of Enterococcus strains as probiotics has recently become controversial due to the ease of acquiring different virulence factors and resistance to various classes of antibiotics. Enterococci are also seen as opportunistic pathogens. This problem is especially relevant in hospital environments, where enterococcal outbreaks often occur. Their ability to translocate from the gastro-intestinal tract to various tissues and organs as well as their virulence and antibiotic resistance are risk factors that hinder eradication. Due to numerous reports on the plasticity of the enterococcal genome and the acquisition of pathogenic microbial features, we ask ourselves, how far is this commensal genus from acquiring pathogenicity? This paper discusses both the beneficial properties of these microorganisms and the risk factors related to their evolution towards pathogenicity.
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Abstract
Worldwide consumers increasingly demand traditional/local products, to which those made from ewe’s milk belong. In Slovakia, dairy products made from ewe’s milk have a long tradition. A total of seventeen farmhouse fresh ewe’s milk lump cheeses from various local farm producers in central Slovakia were sampled at farms and then analyzed. Based on the sequencing data analysis, the phylum Firmicutes dominated (60.92%) in ewe’s lump cheeses, followed with the phylum Proteobacteria (38.23%), Actinobacteria (0.38%) and Bacteroidetes (0.35%). The phylum Firmicutes was represented by six genera, among which the highest amount possessed the genus Streptococcus (41.13%) followed with the genus Lactococcus (8.54%), Fructobacillus (3.91%), Enterococcus (3.18%), Staphylococcus (1.80%) and the genus Brochotrix (0.08%). The phylum Proteobacteria in ewe’s lump cheeses involved eight Gram-negative genera: Pseudomonas, Acinetobacter, Enterobacter, Ewingella, Escherichia-Shigella, Pantoea and Moraxella. The phylum Bacteroidetes involved three genera: Bacteroides, Sphingobacterium and Chrysobacterium. Results presented are original; the microbiome of Slovak ewe’s milk lump cheese has been not analyzed at those taxonomic levels up to now.
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Enterococcal Species Associated with Slovak Raw Goat Milk, Their Safety and Susceptibility to Lantibiotics and Durancin ED26E/7. Processes (Basel) 2021. [DOI: 10.3390/pr9040681] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Goat milk has become a popular item of human consumption due to its originality. Enterococci are ubiquitous bacteria, and they can also be found in traditional dairy products. This study focuses on the safety of enterococci from Slovak raw goat milk and on their susceptibility to lantibiotic bacteriocins and durancin ED26E/7, which has not previously been studied. Biofilm formation ability in enterococci, virulence factor genes, enzyme production and antibiotic profile were investigated. Samples of raw goat milk (53) were collected from 283 goats in Slovakia. MALDI-TOF mass spectrometry identified three enterococcal species: Enterococcus faecium, E. hirae and E. mundtii, with dominant occurrence of the species E. faecium. Low-grade biofilm formation ability (0.1 ≤ A570 < 1.0) was found in four strains of E. faecium. Gelatinase, hyaluronidase, aggregation substance and enterococcal surface protein genes were absent in these enterococci. Gene efaAfm (adhesin) was detected in five E. faecium strains. However, it was not detected in biofilm-forming strains. Enterococci detected in Slovak raw goat milk were found not to have pathogenic potential; four strains even produced high amounts of useful β-galactosidase. The strains were susceptible to lantibiotic bacteriocin treatment and to durancin ED26E/7 as well, which represents original information in dairy production.
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O'Grady J, Cronin U, Tierney J, Piterina AV, O'Meara E, Wilkinson MG. Gaps in the assortment of rapid assays for microorganisms of interest to the dairy industry. ADVANCES IN APPLIED MICROBIOLOGY 2020; 113:1-56. [PMID: 32948264 PMCID: PMC7426214 DOI: 10.1016/bs.aambs.2020.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This review presents the results of a study into the offering of rapid microbial detection assays to the Irish dairy industry. At the outset, a consultation process was undertaken whereby key stakeholders were asked to compile a list of the key microorganisms of interest to the sector. The resultant list comprises 19 organisms/groups of organisms divided into five categories: single pathogenic species (Cronobacter sakazakii, Escherichia coli and Listeria monocytogenes); genera containing pathogenic species (Bacillus, Clostridium, Listeria, Salmonella; Staphylococcus); broad taxonomic groupings (Coliforms, Enterobacteriaceae, fecal Streptococci, sulfite reducing bacteria/sulfite reducing Clostridia [SRBs/SRCs], yeasts and molds); organisms displaying certain growth preferences or resistance as regards temperature (endospores, psychrotrophs, thermodurics, thermophiles); indicators of quality (total plate count, Pseudomonas spp.). A survey of the rapid assays commercially available for the 19 organisms/groups of organisms was conducted. A wide disparity between the number of rapid tests available was found. Four categories were used to summarize the availability of rapid assays per organism/group of organisms: high coverage (>15 assays available); medium coverage (5-15 assays available); low coverage (<5 assays available); no coverage (0 assays available). Generally, species or genera containing pathogens, whose presence is regulated-for, tend to have a good selection of commercially available rapid assays for their detection, whereas groups composed of heterogenous or even undefined genera of mainly spoilage organisms tend to be "low coverage" or "no coverage." Organisms/groups of organisms with "low coverage" by rapid assays include: Clostridium spp.; fecal Streptococci; and Pseudomonas spp. Those with "no coverage" by rapid assays include: endospores; psychrotrophs; SRB/SRCs; thermodurics; and thermophiles. An important question is: why have manufacturers of rapid microbiological assays failed to respond to the necessity for rapid methods for these organisms/groups of organisms? The review offers explanations, ranging from the technical difficulty involved in detecting as broad a group as the thermodurics, which covers the spores of multiple sporeforming genera as well at least six genera of mesophilic nonsporeformers, to the taxonomically controversial issue as to what constitutes a fecal Streptococcus or SRBs/SRCs. We review two problematic areas for assay developers: validation/certification and the nature of dairy food matrices. Development and implementation of rapid alternative test methods for the dairy industry is influenced by regulations relating to both the microbiological quality standards and the criteria alternative methods must meet to qualify as acceptable test methods. However, the gap between the certification of developer's test systems as valid alternative methods in only a handful of representative matrices, and the requirement of dairy industries to verify the performance of alternative test systems in an extensive and diverse range of dairy matrices needs to be bridged before alternative methods can be widely accepted and adopted in the dairy industry. This study concludes that many important dairy matrices have effectively been ignored by assay developers.
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Affiliation(s)
- John O'Grady
- Dairy Processing Technology Centre, University of Limerick, Limerick, Ireland
| | - Ultan Cronin
- Department of Biological Sciences, University of Limerick, Limerick, Ireland.
| | - Joseph Tierney
- Glanbia Ingredients Ireland, Ballyragget, Co. Kilkenny, Ireland
| | - Anna V Piterina
- Dairy Processing Technology Centre, University of Limerick, Limerick, Ireland
| | - Elaine O'Meara
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
| | - Martin G Wilkinson
- Department of Biological Sciences, University of Limerick, Limerick, Ireland
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Chajęcka-Wierzchowska W, Zadernowska A, García-Solache M. Ready-to-eat dairy products as a source of multidrug-resistant Enterococcus strains: Phenotypic and genotypic characteristics. J Dairy Sci 2020; 103:4068-4077. [DOI: 10.3168/jds.2019-17395] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 01/16/2020] [Indexed: 12/22/2022]
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Graham K, Stack H, Rea R. Safety, beneficial and technological properties of enterococci for use in functional food applications - a review. Crit Rev Food Sci Nutr 2020; 60:3836-3861. [PMID: 31924117 DOI: 10.1080/10408398.2019.1709800] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Enterococci are ubiquitous lactic acid bacteria (LAB) that predominantly reside in the gastrointestinal tract of humans and animals but are also widespread in food and the environment due to their robust nature. Enterococci have the paradoxical position of providing several benefits of technological interest in food fermentations but are also considered as opportunistic pathogens capable of causing infection in immunocompromised patients. Several species of the genus have been correlated with disease development in humans such as bacteremia, urinary tract infections, and endocarditis. The pathogenesis of enterococci has been attributed to the increasing incidence of antibiotic resistance and the possession of virulence determinants. On the contrary, enterococci have led to improvements in the aroma, texture, and flavor of fermented dairy products, while their beneficial use as probiotic and protective cultures has also been documented. Furthermore, they have emerged as important candidates for the generation of bioactive peptides, particularly from milk, which provide new opportunities for the development of functional foods and nutraceuticals for human nutrition and health. The detection of pathogenic traits among some species is compromising their use in food applications and subsequently, the genus neither has Generally Regarded as Safe (GRAS) status nor has it been included in the Qualified Presumption of Safety (QPS) list. Nevertheless, the use of certain enterococcal strains in food has been permitted on the basis of a case-by-case assessment. Promisingly, enterococcal virulence factors appear strain specific and food isolates harbor fewer determinants than clinical isolates, while they also remain largely susceptible to clinically relevant antibiotics and thus, have a lower potential for pathogenicity. Ideally, strains considered for use in foods should not possess any virulence determinants and should be susceptible to clinically relevant antibiotics. Implementation of an appropriate risk/benefit analysis, establishment of a strain's innocuity, and consideration for relevant guidelines, legislation, and regulatory aspects surrounding functional food development, may help industry, health-staff and consumers accept enterococci, like other LAB, as important candidates for useful and beneficial applications in food biotechnology.
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Affiliation(s)
- Ken Graham
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Helena Stack
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Rosemary Rea
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
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Patcas R, Zbinden R, Schätzle M, Schmidlin PR, Zehnder M. Whisky, microwave or hairdryer? Exploring the most efficient way to reduce bacterial colonisation on contaminated toothbrushes. Br Dent J 2019; 225:1007-1010. [PMID: 30547935 DOI: 10.1038/sj.bdj.2018.1030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2018] [Indexed: 01/28/2023]
Abstract
Aims It is the holiday season, but your toothbrush does not look very festive. It is damp and has been used and contaminated by someone else. To rectify this heinous crime, this study investigates the effectiveness of three household objects to disinfect toothbrushes. Design In-vitro study performed under conditions simulating everyday life. Materials and methods Twenty toothbrushes were contaminated using a mixture of saliva and trypticase soy broth containing Escherichia coli and Enterococcus faecalis. These contaminated toothbrushes were submerged in whisky, cooked in a microwave oven, or exposed to the hot air stream of a hairdryer, separately. Each treatment was performed on five toothbrushes for one minute. Untreated specimens (n = 5) served as controls. Toothbrushes were subsequently sonicated in sterile physiological saline, which was plated on selective agars. Bacterial counts were graded as low, medium, or high. Results Residual contamination was influenced by the disinfectant applied, both in E. coli (p <0.001) and E. faecalis (p = 0.019). Microwave cooking achieved highest decontamination, while whisky had no significant effect on bacterial counts over no treatment (p = 0.8). Hot air showed some limited effectiveness under current conditions. Conclusions Microwave oven cooking appears to be a simple, cheap, and effective way to reduce bacterial contamination of your toothbrush.
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Affiliation(s)
- R Patcas
- Center of Dental Medicine, University of Zurich, Clinic of Orthodontics and Pediatric, Dentistry, Plattenstr. 11, Zurich, 8032, Switzerland
| | - R Zbinden
- Institute of Medical Microbiology, University of Zurich, Zurich, 8032, Switzerland
| | - M Schätzle
- Center of Dental Medicine, University of Zurich, Clinic of Orthodontics and Pediatric, Dentistry, Plattenstr. 11, Zurich, 8032, Switzerland
| | - P R Schmidlin
- Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich, 8032, Switzerland
| | - M Zehnder
- Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Zurich, 8032, Switzerland
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Microbiota of Sardinian Goat's Milk and Preliminary Characterization of Prevalent LAB Species for Starter or Adjunct Cultures Development. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6131404. [PMID: 31360718 PMCID: PMC6644507 DOI: 10.1155/2019/6131404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 11/21/2022]
Abstract
This work was performed to study the microbiota of raw goat's milk (67 samples) collected in different areas of Sardinia, in order to select autochthonous lactic acid bacteria (LAB) strains for use in goat cheese manufacturing. Total mesophilic bacteria ranged between 105 and 107 cfu/mL; mean counts of Enterobacteriaceae did not exceed 4 log cfu/mL whereas those of E. coli and coagulase-positive staphylococci were lower than 1.5 and 2 log ufc /ml, respectively. Neither Salmonella spp. nor Listeria monocytogenes were recovered. The numbers of total LAB were in the range from 104 to 107 cfu/mL and mean yeasts counts varied between 103 and 105 cfu/mL. The most frequently isolated LAB species were Lactococcus lactis subsp. lactis and Lactobacillus paracasei. The presence of Enterococcus faecium was also noteworthy. The in vitro study of some functional characteristics related to technological properties of the strains belonging to these species allowed to point out some strains possessing good potential for use as adjunct or starter cultures in the production of cheese.
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13
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Yunita D, Dodd CE. Microbial community dynamics of a blue-veined raw milk cheese from the United Kingdom. J Dairy Sci 2018; 101:4923-4935. [DOI: 10.3168/jds.2017-14104] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/10/2018] [Indexed: 11/19/2022]
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14
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Santos Rosado Castro M, da Silva Fernandes M, Kabuki DY, Kuaye AY. Biofilm formation ofEnterococcus faeciumon stainless steel surfaces: Modeling and control by disinfection agents. J FOOD PROCESS ENG 2017. [DOI: 10.1111/jfpe.12663] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marcília Santos Rosado Castro
- Division of Food, Federal Institute of São Paulo - Campus Barretos, Avenida C1, 250 - Bairro Ide Daher - Barretos; SP Brazil
| | - Meg da Silva Fernandes
- Department of Food Technology; University of Campinas (UNICAMP), Rua Monteiro Lobato, 80 - Cidade Universitária Zeferino Vaz - Campinas; SP Brazil
| | - Dirce Yorika Kabuki
- Department of Food Science; University of Campinas (UNICAMP), Rua Monteiro Lobato, 80 - Cidade Universitária Zeferino Vaz - Campinas; SP Brazil
| | - Arnaldo Yoshiteru Kuaye
- Department of Food Technology; University of Campinas (UNICAMP), Rua Monteiro Lobato, 80 - Cidade Universitária Zeferino Vaz - Campinas; SP Brazil
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15
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The individual contribution of starter and non-starter lactic acid bacteria to the volatile organic compound composition of Caciocavallo Palermitano cheese. Int J Food Microbiol 2017; 259:35-42. [PMID: 28783535 DOI: 10.1016/j.ijfoodmicro.2017.07.022] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/29/2017] [Accepted: 07/30/2017] [Indexed: 11/21/2022]
Abstract
The contribution of two starter (Lactobacillus delbrueckii and Streptococcus thermophilus) and nine non-starter (Enterococcus casselliflavus, Enterococcus faecalis, Enterococcus durans, Enterococcus gallinarum, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, Pediococcus acidilactici and Pediococcus pentosaceus) species of lactic acid bacteria (LAB) to the volatile organic compounds (VOCs) of Caciocavallo Palermitano cheese was investigated. The strains used in this study were isolated during the production/ripening of the stretched cheese and tested in a cheese-based medium (CBM). The fermented substrates were analyzed for the growth of the single strains and subjected to the head space solid phase micro-extraction (HS-SPME) and gas chromatography - mass spectrometry (GC-MS). The 11 strains tested were all able to increase their numbers in CBM, even though the development of the starter LAB was quite limited. GC-MS analysis registered 43 compounds including seven chemical classes. A lower diversity of VOCs was registered for the unfermented curd based medium (CuBM) analyzed for comparison. The class of ketones represented a consistent percentage of the VOCs for almost all LAB, followed by alcohols and esters. The volatile profile of Pediococcus acidilactici and Lactobacillus delbrueckii was mainly characterized by 2-butanol, butanoic acid and hexanoic acid and their esters, while that of Lactobacillus casei and Lactobacillus rhamnosus was characterized by 2,3-butanedione and 2-butanone, 3-hydroxy. In order to correlate the VOCs produced by Caciocavallo Palermitano cheeses with those generated by individual LAB, the 4-month ripened cheeses resulting from the dairy process monitored during the isolation of LAB were also analyzed for the volatile chemical fraction and the compounds in common were subjected to a multivariate statistical analysis. The canonical analysis indicated that the VOCs of the ripened cheeses were mainly influenced by E. gallinarum, L. paracasei, L. delbrueckii, L. rhamnosus and L. casei and that 1-hexanol, o-xylene and m-xylene were the cheese VOCs highly correlated with LAB.
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Rosado de Castro M, da Silva Fernandes M, Kabuki DY, Kuaye AY. Biofilm formation on stainless steel as a function of time and temperature and control through sanitizers. Int Dairy J 2017. [DOI: 10.1016/j.idairyj.2016.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Development of a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci. J Microbiol Methods 2016; 132:99-105. [PMID: 27894832 DOI: 10.1016/j.mimet.2016.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 11/24/2022]
Abstract
Enterococci show higher proteolytic activities than other lactic acid bacteria and thus have received considerable attention in scientific literature in recent years. Proteolytic enzymes of enterococci have warranted the use of some species as starter, adjuncts or protective cultures and as probiotics, while in some strains they have also been linked with virulence. Consequently, the isolation and identification of proteolytic enterococci is becoming of increasing interest and importance. However, current screening methods for proteolytic enterococci can be time consuming, requiring a two-step procedure which may take up to 96h. This study describes a method, utilising Kanamycin Skim Milk Aesculin Azide (KSMEA) agar, for the isolation of proteolytic enterococci in one-step, thereby significantly reducing screening time. KSMEA combines the selective properties of Kanamycin Aesculin Azide Agar (KAA) with skim milk powder for the detection of proteolytic enterococci. Enterococci produced colonies with a black halo on KSMEA which were accompanied by a zone of clearing in the media when enterococci were proteolytic. KSMEA medium retained the selectivity of KAA, while proteolytic enterococci were easily distinguished from non-proteolytic enterococci when two known strains were propagated on KSMEA. KSMEA also proved effective at isolating and detecting enterococci in raw milk, faeces and soil. Isolates recovered from the screen were confirmed as enterococci using genus-specific primers. Proteolytic enterococci were present in the raw milk sample only and were easily distinguishable from non-proteolytic enterococci and other microorganisms. Therefore, KSMEA provides a rapid, one-step screening method for the isolation of presumptive proteolytic enterococci.
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Carafa I, Clementi F, Tuohy K, Franciosi E. Microbial evolution of traditional mountain cheese and characterization of early fermentation cocci for selection of autochtonous dairy starter strains. Food Microbiol 2016; 53:94-103. [DOI: 10.1016/j.fm.2015.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/25/2015] [Accepted: 09/03/2015] [Indexed: 11/28/2022]
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McAuley CM, Britz ML, Gobius KS, Craven HM. Prevalence, seasonality, and growth of enterococci in raw and pasteurized milk in Victoria, Australia. J Dairy Sci 2015; 98:8348-58. [PMID: 26476940 DOI: 10.3168/jds.2015-9335] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 08/20/2015] [Indexed: 11/19/2022]
Abstract
This study investigated the prevalence, seasonality, and species variety of enterococci present in raw milk factory silos and pasteurized milk in 3 dairying regions in Victoria, Australia, over a 1-yr period. Additionally, the growth ability of thermoduric enterococci isolated in this study (Enterococcus faecalis, E. faecium, E. hirae, and E. durans) was determined in milk at temperatures likely to occur during storage, transport, and distribution, and before domestic consumption (4 and 7°C). Enterococci were detected in 96% of 211 raw milk samples, with an average count of 2.48 log10 cfu/mL. Counts were significantly lower in winter than summer (average 1.84 log10 cfu/mL) and were different between factories but not regions. Enterococcus faecalis was the most prevalent species isolated from raw milk in every factory, comprising between 61.5 and 83.5% of enterococcal species across each season. Enterococci were detected in lower numbers in pasteurized milk than in raw milk and were below the limit of detection on spread plates (<10 cfu/mL) after factory pasteurization. Residual viable cells were only detected following enrichment using 100-mL samples of milk, with 20.8% of the samples testing positive; this equated to a decrease in the average raw milk enterococci count of >4 log10 cfu/mL following pasteurization. Although E. faecalis predominated in raw milk and E. durans was found in only 2.9% of raw milk samples, E. durans was the most prevalent species detected in pasteurized milk. The detection of enterococci in the pasteurized milk did not correlate with higher enterococci counts in the raw milk. This suggested that the main enterococci populations in raw milk were heat-sensitive and that thermoduric enterococci survived pasteurization in a small numbers of instances. All of the thermoduric enterococci that were assessed for growth at likely refrigeration temperatures were able to grow at both 4 and 7°C in sterile milk, with generation times of 35 to 41h and 16 to 22h, respectively. Thermoduric enterococci were detected in pasteurized milk stored at 4°C for 2 wk (typically 1 to 9 cells/100mL, up to 2.82 log10 cfu/mL), demonstrating the potential of enterococci to survive pasteurization and contribute to milk spoilage at refrigeration temperatures. This is particularly relevant for milk that is aseptically packaged to exclude gram-negative psychrotrophic bacteria and kept above the recommended storage temperature of ≤5°C.
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Affiliation(s)
- Catherine M McAuley
- CSIRO Food and Nutrition Flagship, Private Bag 16, Werribee, Victoria, Australia, 3030; Melbourne School of Land and Environment, University of Melbourne, Melbourne, Victoria, Australia, 3010.
| | - Margaret L Britz
- Melbourne School of Land and Environment, University of Melbourne, Melbourne, Victoria, Australia, 3010
| | - Kari S Gobius
- CSIRO Food and Nutrition Flagship, Private Bag 16, Werribee, Victoria, Australia, 3030
| | - Heather M Craven
- CSIRO Food and Nutrition Flagship, Private Bag 16, Werribee, Victoria, Australia, 3030
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Terzić-Vidojević A, Veljović K, Begović J, Filipić B, Popović D, Tolinački M, Miljković M, Kojić M, Golić N. Diversity and antibiotic susceptibility of autochthonous dairy enterococci isolates: are they safe candidates for autochthonous starter cultures? Front Microbiol 2015; 6:954. [PMID: 26441888 PMCID: PMC4563272 DOI: 10.3389/fmicb.2015.00954] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/28/2015] [Indexed: 01/07/2023] Open
Abstract
Enterococci represent the most controversial group of dairy bacteria. They are found to be the main constituent of many traditional Mediterranean dairy products and contribute to their characteristic taste and flavor. On the other hand, during the last 50 years antibiotic-resistant enterococci have emerged as leading causes of nosocomial infections worldwide. The aim of this study was to determine the diversity, technological properties, antibiotic susceptibility and virulence traits of 636 enterococci previously isolated from 55 artisan dairy products from 12 locations in the Western Balkan countries (WBC) of Serbia, Croatia and Bosnia and Herzegovina. All strains were identified both by microbiological and molecular methods. The predominant species was Enterococcus durans, followed by Enterococcus faecalis and Enterococcus faecium. Over 44% of the isolates were resistant to ciprofloxacin and erythromycin, while 26.2% of the isolates were multi-resistant to three or more antibiotics belonging to different families. 185 isolates (29.1%) were susceptible to all 13 of the antibiotics tested. The antibiotic-susceptible isolates were further tested for possible virulence genes and the production of biogenic amines. Finally, five enterococci isolates were found to be antibiotic susceptible with good technological characteristics and without virulence traits or the ability to produce biogenic amines, making them possible candidates for biotechnological application as starter cultures in the dairy industry.
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Affiliation(s)
- Amarela Terzić-Vidojević
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Katarina Veljović
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Jelena Begović
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Brankica Filipić
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia ; Faculty of Pharmacy, University of Belgrade Belgrade, Serbia
| | - Dušanka Popović
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Maja Tolinački
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Marija Miljković
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Milan Kojić
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
| | - Nataša Golić
- Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia
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Fernandes MDS, Fujimoto G, de Souza LP, Kabuki DY, da Silva MJ, Kuaye AY. Dissemination of Enterococcus faecalis and Enterococcus faecium in a ricotta processing plant and evaluation of pathogenic and antibiotic resistance profiles. J Food Sci 2015; 80:M765-75. [PMID: 25874819 DOI: 10.1111/1750-3841.12824] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 01/28/2015] [Indexed: 11/29/2022]
Abstract
In this work, the sources of contamination by Enterococcus spp. in a ricotta processing line were evaluated. The isolated strains were tested for virulence genes (gelE, cylA,B, M, esp, agg, ace, efaA, vanB), expression of virulence factors (hemolysin and gelatinase), and the resistance to 10 different antibiotics. Enterococcus faecium and Enterococcus faecalis were subjected to discriminatory identification by intergenic spacer region (ITS)-polymerase chain reaction and sequencing of the ITS region. The results showed that Enterococcus spp. was detected in the raw materials, environment samples and the final product. None of the 107 Enterococcus isolates were completely free from all virulence genes considered. A fraction of 21.5% of the isolates containing all of the genes of the cylA, B, M operon also expressed β-hemolysis. Most of the isolates showed the gelE gene, but only 9.3% were able to hydrolyze gelatin. In addition, 23.5% of the observed Enterococcus isolates had the vanB gene but were susceptible to vancomycin in vitro. The dissemination of antibiotic-resistant enterococci was revealed in this study: 19.3% of the E. faecium samples and 78.0% of the E. faecalis samples were resistant to at least one of the antibiotics tested. Sequencing of region discriminated 5 and 7 distinct groups among E. faecalis and E. faecium, respectively. Although some similarity was observed among some of the isolates, all E. faecalis and E. faecium isolates had genetic differences both in the ITS region and in the virulence profile, which makes them different from each other.
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Affiliation(s)
- Meg da Silva Fernandes
- Dept. of Food Technology, Univ. of Campinas (UNICAMP), Rua Monteiro Lobato, 80 - Cidade Universitária Zeferino Vaz, CEP 13083-862, P.O. Box 6121, Campinas, SP, Brazil
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Phenotypic and genotypic characterization of lactic acid bacteria isolated from raw goat milk and effect of farming practices on the dominant species of lactic acid bacteria. Int J Food Microbiol 2015; 210:9-15. [PMID: 26082325 DOI: 10.1016/j.ijfoodmicro.2015.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 10/23/2014] [Accepted: 02/02/2015] [Indexed: 11/22/2022]
Abstract
Lactic acid bacteria, in particular Lactococcus lactis, play a decisive role in the cheese making process and more particularly in lactic cheeses which are primarily produced on goat dairy farms. The objective of this study was therefore to identify the main lactic acid bacteria found in raw goats' milk from three different regions in France and evaluate if certain farming practices have an effect on the distribution of species of lactic acid bacteria in the various milk samples. Identification at genus or species level was carried out using phenotypic tests and genotypic methods including repetitive element REP-PCR, species-specific PCR and 16S rRNA gene sequencing. The distribution of the main bacterial species in the milk samples varied depending on farms and their characteristics. Out of the 146 strains identified, L. lactis was the dominant species (60% of strains), followed by Enterococcus (38%) of which Enterococcus faecalis and Enterococcus faecium. Within the species L. lactis, L. lactis subsp lactis was detected more frequently than L. lactis subsp cremoris (74% vs. 26%). The predominance of L. lactis subsp cremoris was linked to geographical area studied. It appears that the animals' environment plays a role in the balance between the dominance of L. lactis and enterococci in raw goats' milk. The separation between the milking parlor and the goat shed (vs no separation) and only straw in the bedding (vs straw and hay) seems to promote L. lactis in the milk (vs enterococci).
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da Silva Fernandes M, Kabuki DY, Kuaye AY. Behavior of Listeria monocytogenes in a multi-species biofilm with Enterococcus faecalis and Enterococcus faecium and control through sanitation procedures. Int J Food Microbiol 2015; 200:5-12. [PMID: 25655573 DOI: 10.1016/j.ijfoodmicro.2015.01.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/25/2014] [Accepted: 01/02/2015] [Indexed: 11/30/2022]
Abstract
The formation of mono-species biofilm (Listeria monocytogenes) and multi-species biofilms (Enterococcus faecium, Enterococcus faecalis, and L. monocytogenes) was evaluated. In addition, the effectiveness of sanitation procedures for the control of the multi-species biofilm also was evaluated. The biofilms were grown on stainless steel coupons at various incubation temperatures (7, 25 and 39°C) and contact times (0, 1, 2, 4, 6 and 8 days). In all tests, at 7°C, the microbial counts were below 0.4 log CFU/cm(2) and not characteristic of biofilms. In mono-species biofilm, the counts of L. monocytogenes after 8 days of contact were 4.1 and 2.8 log CFU/cm(2) at 25 and 39°C, respectively. In the multi-species biofilms, Enterococcus spp. were present at counts of 8 log CFU/cm(2) at 25 and 39°C after 8 days of contact. However, the L. monocytogenes in multi-species biofilms was significantly affected by the presence of Enterococcus spp. and by temperature. At 25°C, the growth of L. monocytogenes biofilms was favored in multi-species cultures, with counts above 6 log CFU/cm(2) after 8 days of contact. In contrast, at 39°C, a negative effect was observed for L. monocytogenes biofilm growth in mixed cultures, with a significant reduction in counts over time and values below 0.4 log CFU/cm(2) starting at day 4. Anionic tensioactive cleaning complemented with another procedure (acid cleaning, disinfection or acid cleaning+disinfection) eliminated the multi-species biofilms under all conditions tested (counts of all micro-organisms<0.4 log CFU/cm(2)). Peracetic acid was the most effective disinfectant, eliminating the multi-species biofilms under all tested conditions (counts of the all microorganisms <0.4 log CFU/cm(2)). In contrast, biguanide was the least effective disinfectant, failing to eliminate biofilms under all the test conditions.
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Silva LF, Casella T, Gomes ES, Nogueira MCL, De Dea Lindner J, Penna ALB. Diversity of Lactic Acid Bacteria Isolated from Brazilian Water Buffalo Mozzarella Cheese. J Food Sci 2015; 80:M411-7. [DOI: 10.1111/1750-3841.12771] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 04/12/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Luana Faria Silva
- UNESP-São Paulo State Univ; Food Engineering and Technology Dept; São José do Rio Preto Brazil
| | - Tiago Casella
- FAMERP-Medical School of São José do Rio Preto; Microbiology Laboratory; São José do Rio Preto Brazil
| | | | | | - Juliano De Dea Lindner
- UFSC-Federal Univ. of Santa Catarina; Food Science and Technology Dept; Florianópolis Brazil
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Burdychová R. Study of enterococci during cheese manufacture and ripening and evaluation of their role in tyramine production. ACTA UNIVERSITATIS AGRICULTURAE ET SILVICULTURAE MENDELIANAE BRUNENSIS 2014. [DOI: 10.11118/actaun200957050049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Delcenserie V, Taminiau B, Delhalle L, Nezer C, Doyen P, Crevecoeur S, Roussey D, Korsak N, Daube G. Microbiota characterization of a Belgian protected designation of origin cheese, Herve cheese, using metagenomic analysis. J Dairy Sci 2014; 97:6046-56. [PMID: 25064656 DOI: 10.3168/jds.2014-8225] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 06/18/2014] [Indexed: 11/19/2022]
Abstract
Herve cheese is a Belgian soft cheese with a washed rind, and is made from raw or pasteurized milk. The specific microbiota of this cheese has never previously been fully explored and the use of raw or pasteurized milk in addition to starters is assumed to affect the microbiota of the rind and the heart. The aim of the study was to analyze the bacterial microbiota of Herve cheese using classical microbiology and a metagenomic approach based on 16S ribosomal DNA pyrosequencing. Using classical microbiology, the total counts of bacteria were comparable for the 11 samples of tested raw and pasteurized milk cheeses, reaching almost 8 log cfu/g. Using the metagenomic approach, 207 different phylotypes were identified. The rind of both the raw and pasteurized milk cheeses was found to be highly diversified. However, 96.3 and 97.9% of the total microbiota of the raw milk and pasteurized cheese rind, respectively, were composed of species present in both types of cheese, such as Corynebacterium casei, Psychrobacter spp., Lactococcus lactis ssp. cremoris, Staphylococcus equorum, Vagococcus salmoninarum, and other species present at levels below 5%. Brevibacterium linens were present at low levels (0.5 and 1.6%, respectively) on the rind of both the raw and the pasteurized milk cheeses, even though this bacterium had been inoculated during the manufacturing process. Interestingly, Psychroflexus casei, also described as giving a red smear to Raclette-type cheese, was identified in small proportions in the composition of the rind of both the raw and pasteurized milk cheeses (0.17 and 0.5%, respectively). In the heart of the cheeses, the common species of bacteria reached more than 99%. The main species identified were Lactococcus lactis ssp. cremoris, Psychrobacter spp., and Staphylococcus equorum ssp. equorum. Interestingly, 93 phylotypes were present only in the raw milk cheeses and 29 only in the pasteurized milk cheeses, showing the high diversity of the microbiota. Corynebacterium casei and Enterococcus faecalis were more prevalent in the raw milk cheeses, whereas Psychrobacter celer was present in the pasteurized milk cheeses. However, this specific microbiota represented a low proportion of the cheese microbiota. This study demonstrated that Herve cheese microbiota is rich and that pasteurized milk cheeses are microbiologically very close to raw milk cheeses, probably due to the similar manufacturing process. The characterization of the microbiota of this particular protected designation of origin cheese was useful in enabling us to gain a better knowledge of the bacteria responsible for the character of this cheese.
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Affiliation(s)
- V Delcenserie
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium.
| | - B Taminiau
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium
| | - L Delhalle
- Quality Partner S.A., Rue Hayeneux, 62 4040 Herstal, Belgium
| | - C Nezer
- Quality Partner S.A., Rue Hayeneux, 62 4040 Herstal, Belgium
| | - P Doyen
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium
| | - S Crevecoeur
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium
| | - D Roussey
- Herve Société, Rue de Charneux, 4650 Herve, Belgium
| | - N Korsak
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium
| | - G Daube
- Fundamental and Applied Research for Animal & Health (FARAH), Food Science Department, Faculty of Veterinary Medicine, University of Liège, Sart-Tilman, B43b Liège, B-4000 Belgium
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Montel MC, Buchin S, Mallet A, Delbes-Paus C, Vuitton DA, Desmasures N, Berthier F. Traditional cheeses: rich and diverse microbiota with associated benefits. Int J Food Microbiol 2014; 177:136-54. [PMID: 24642348 DOI: 10.1016/j.ijfoodmicro.2014.02.019] [Citation(s) in RCA: 356] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 02/17/2014] [Accepted: 02/22/2014] [Indexed: 11/26/2022]
Abstract
The risks and benefits of traditional cheeses, mainly raw milk cheeses, are rarely set out objectively, whence the recurrent confused debate over their pros and cons. This review starts by emphasizing the particularities of the microbiota in traditional cheeses. It then describes the sensory, hygiene, and possible health benefits associated with traditional cheeses. The microbial diversity underlying the benefits of raw milk cheese depends on both the milk microbiota and on traditional practices, including inoculation practices. Traditional know-how from farming to cheese processing helps to maintain both the richness of the microbiota in individual cheeses and the diversity between cheeses throughout processing. All in all more than 400 species of lactic acid bacteria, Gram and catalase-positive bacteria, Gram-negative bacteria, yeasts and moulds have been detected in raw milk. This biodiversity decreases in cheese cores, where a small number of lactic acid bacteria species are numerically dominant, but persists on the cheese surfaces, which harbour numerous species of bacteria, yeasts and moulds. Diversity between cheeses is due particularly to wide variations in the dynamics of the same species in different cheeses. Flavour is more intense and rich in raw milk cheeses than in processed ones. This is mainly because an abundant native microbiota can express in raw milk cheeses, which is not the case in cheeses made from pasteurized or microfiltered milk. Compared to commercial strains, indigenous lactic acid bacteria isolated from milk/cheese, and surface bacteria and yeasts isolated from traditional brines, were associated with more complex volatile profiles and higher scores for some sensorial attributes. The ability of traditional cheeses to combat pathogens is related more to native antipathogenic strains or microbial consortia than to natural non-microbial inhibitor(s) from milk. Quite different native microbiota can protect against Listeria monocytogenes in cheeses (in both core and surface) and on the wooden surfaces of traditional equipment. The inhibition seems to be associated with their qualitative and quantitative composition rather than with their degree of diversity. The inhibitory mechanisms are not well elucidated. Both cross-sectional and cohort studies have evidenced a strong association of raw-milk consumption with protection against allergic/atopic diseases; further studies are needed to determine whether such association extends to traditional raw-milk cheese consumption. In the future, the use of meta-omics methods should help to decipher how traditional cheese ecosystems form and function, opening the way to new methods of risk-benefit management from farm to ripened cheese.
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Affiliation(s)
| | - Solange Buchin
- INRA, UR342 Technologie et Analyses Laitières, F-39801 Poligny, France
| | - Adrien Mallet
- Normandie Univ, France; UNICAEN, ABTE, F-14032 Caen, France
| | - Céline Delbes-Paus
- INRA, Unité Recherches Fromagères, 20 Côte de Reyne, F-15000 Aurillac, France
| | - Dominique A Vuitton
- UNICAEN, ABTE, F-14032 Caen, France; EA3181/Université de Franche-Comté, 25030, Besançon, France
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De Filippis F, La Storia A, Stellato G, Gatti M, Ercolini D. A selected core microbiome drives the early stages of three popular italian cheese manufactures. PLoS One 2014; 9:e89680. [PMID: 24586960 PMCID: PMC3933672 DOI: 10.1371/journal.pone.0089680] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 01/22/2014] [Indexed: 02/07/2023] Open
Abstract
Mozzarella (M), Grana Padano (GP) and Parmigiano Reggiano (PR) are three of the most important traditional Italian cheeses. In the three cheese manufactures the initial fermentation is carried out by adding natural whey cultures (NWCs) according to a back-slopping procedure. In this study, NWCs and the corresponding curds from M, GP and PR manufactures were analyzed by culture-independent pyrosequencing of the amplified V1–V3 regions of the 16S rRNA gene, in order to provide insights into the microbiota involved in the curd acidification. Moreover, culture-independent high-throughput sequencing of lacS gene amplicons was carried out to evaluate the biodiversity occurring within the S. thermophilus species. Beta diversity analysis showed a species-based differentiation between GP-PR and M manufactures indicating differences between the preparations. Nevertheless, all the samples shared a naturally-selected core microbiome, that is involved in the curd acidification. Type-level variability within S. thermophilus species was also found and twenty-eight lacS gene sequence types were identified. Although lacS gene did not prove variable enough within S. thermophilus species to be used for quantitative biotype monitoring, the possibility of using non rRNA targets for quantitative biotype identification in food was highlighted.
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Affiliation(s)
- Francesca De Filippis
- Division of Microbiology, Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Antonietta La Storia
- Division of Microbiology, Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Giuseppina Stellato
- Division of Microbiology, Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Monica Gatti
- Department of Food Science, University of Parma, Parma, Italy
- Multidisciplinary Interdepartmental Dairy Center - MILC, University of Parma, Parma, Italy
| | - Danilo Ercolini
- Division of Microbiology, Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
- * E-mail:
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Bae HS, Hou A. 23S rRNA gene-based enterococci community signatures in Lake Pontchartrain, Louisiana, USA, following urban runoff inputs after Hurricane Katrina. MICROBIAL ECOLOGY 2013; 65:289-301. [PMID: 23269456 DOI: 10.1007/s00248-012-0166-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 12/11/2012] [Indexed: 06/01/2023]
Abstract
Little is known about the impacts of fecal polluted urban runoff inputs on the structure of enterococci communities in estuarine waters. This study employed a 23S rRNA gene-based polymerase chain reaction (PCR) assay with newly designed genus-specific primers, Ent127F-Ent907R, to determine the possible impacts of Hurricane Katrina floodwaters via the 17th Street Canal discharge on the community structure of enterococci in Lake Pontchartrain. A total of 94 phylotypes were identified through the restriction fragment length polymorphism (RFLP) screening of 494 clones while only 8 phylotypes occurred among 88 cultivated isolates. Sequence analyses of representative phylotypes and their temporal and spatial distribution in the lake and the canal indicated the Katrina floodwater input introduced a large portion of Enterococcus flavescens, Enterococcus casseliflavus, and Enterococcus dispar into the lake; typical fecal groups Enterococcus faecium, Enterococcus durans, Enterococcus hirae, and Enterococcus mundtii were detected primarily in the floodwater-impacted waters. This study provides a global picture of enterococci in estuarine waters impacted by Hurricane Katrina-derived urban runoff. It also demonstrates the culture-independent PCR approach using 23S rRNA gene as a molecular marker could be a good alternative in ecological studies of enterococci in natural environments to overcome the limitation of conventional cultivation methods.
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Affiliation(s)
- Hee-Sung Bae
- Department of Environmental Sciences, School of Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA
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de Garnica ML, Linage B, Carriedo JA, De La Fuente LF, García-Jimeno MC, Santos JA, Gonzalo C. Relationship among specific bacterial counts and total bacterial and somatic cell counts and factors influencing their variation in ovine bulk tank milk. J Dairy Sci 2012. [PMID: 23200475 DOI: 10.3168/jds.2012-5915] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To analyze the relationship among the counts of different organisms and total bacterial count (BTTBC) and somatic cell count (BTSCC) as determined in dairy laboratories in ovine bulk tank milk, 751 bulk tank milk samples from 205 dairy sheep flocks belonging to Consortium for Ovine Promotion (CPO) were collected between January and December 2011. Four samplings were carried out in each flock, once per season, throughout 1 yr. Variables analyzed were bulk tank counts of thermoduric, psychrotrophic, coliform, and gram-positive catalase-negative cocci (GPCNC) bacterial groups. Thermoduric, psychrotrophic, and coliform species were significantly related to BTTBC, whereas GPCNC were correlated with both BTTBC and BTSCC variables. Highest counts were for psychrotroph and coliform groups, and a moderate to high correlation (r=0.51) was found between both variables, indicating that poor cleaning practices in the flocks tend to select for less-resistant organisms, such as gram-negative rods. In addition, BTTBC correlated with BTSCC (r=0.42). Some variation factors for specific bacterial counts, such as breed, season, milking type, dry therapy, and milk yield, were also analyzed. Flock information was collected from flock books, annual audits, and the CPO traceability system. Psychrotrophs and coliforms had elevated counts in winter, whereas GPCNC were higher in summer and in hand-milked flocks. Dry therapy contributed to the reduction in psychrotrophic bacteria; therefore, some strains of mammary pathogens could also be psychrotrophic bacteria. Results of this study would be helpful for troubleshooting milk quality problems and developing premium payment systems in dairy sheep.
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Affiliation(s)
- M L de Garnica
- Departamento de Producción Animal, Facultad de Veterinaria, Universidad de León, 24071-León, Spain
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Production of bacteriocins by Enterococcus spp. isolated from traditional, Iranian, raw milk cheeses, and detection of their encoding genes. Eur Food Res Technol 2012. [DOI: 10.1007/s00217-012-1697-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Duckova V, Čanigová M, Kročko M, Bezeková J. Antibacterial activity of thyme and rosemary essential oil against Enterococci isolated from meat. POTRAVINARSTVO 2012. [DOI: 10.5219/178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Traditionally enterococci are considered as part of the lactic acid bacteria. This group of bacteria contaminating mostly food of animal origin and some of them can be resistant to antibiotic. The consumers prefer safe foods free of synthetic additives and therefore interest for natural preservatives is increasing in recent years. The aim of this work was to determine antibacterial activity of essential oil from thyme and rosemary against enterococci. Strains of enterococci were isolated from poultry and pork. The isolates of enterococci were identified as E. faecalis and E. mundtii and their sensitivity to chosen antibiotic (ampicillin, erythromycin, gentamicin, tetracycline and vancomycin) was determined. Enterococci were experimentally inoculated in nutrient broth at concentration 3 - 4 log cfu.ml-1. The influence of thyme and rosemary essential oil at different concentrations and at different temperatures (6 °C and 25 °C) against enterococci was tested. As more effective has proved thyme oil, which reliably inhibited both strains at concentration of 0.05 % at 6 and 25 °C. Rosemary oil at the highest tested concentrations (of 1 %, respectively 1.5 %) only reduced the number of tested strains of enterococci. The higher antibacterial activity of essential oils was determined at 25 °C.
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Rosales-Castillo JA, Vázquez-Garcidueñas MS, Álvarez-Hernández H, Chassin-Noria O, Varela-Murillo AI, Zavala-Páramo MG, Cano-Camacho H, Vázquez-Marrufo G. Genetic diversity and population structure of Escherichia coli from neighboring small-scale dairy farms. J Microbiol 2011; 49:693-702. [DOI: 10.1007/s12275-011-0461-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 04/21/2011] [Indexed: 10/15/2022]
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Choi HY, Kim JS, Kim WJ. Optimization of Conditions for the Maximum Bacteriocin Production of Enterococcus faecium DB1 Using Response Surface Methodology. Korean J Food Sci Anim Resour 2011. [DOI: 10.5851/kosfa.2011.31.2.176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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El-Ghaish S, Dalgalarrondo M, Choiset Y, Sitohy M, Ivanova I, Haertlé T, Chobert JM. Screening of strains of Lactococci isolated from Egyptian dairy products for their proteolytic activity. Food Chem 2010. [DOI: 10.1016/j.foodchem.2009.11.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Colombo F, Borgo F, Fortina MG. Genotypic characterization of non starter lactic acid bacteria involved in the ripening of artisanal Bitto PDO cheese. J Basic Microbiol 2009; 49:521-30. [DOI: 10.1002/jobm.200800381] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Martín B, Corominas L, Garriga M, Aymerich T. Identification and tracing ofEnterococcusspp. by RAPD-PCR in traditional fermented sausages and meat environment. J Appl Microbiol 2009; 106:66-77. [DOI: 10.1111/j.1365-2672.2008.03976.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Templer SP, Rohner P, Baumgartner A. Relation of Enterococcus faecalis and Enterococcus faecium isolates from foods and clinical specimens. J Food Prot 2008; 71:2100-4. [PMID: 18939760 DOI: 10.4315/0362-028x-71.10.2100] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Clinical Enterococcus faecalis (n=65) and Enterococcus faecium (n=12) blood isolates from three Swiss hospitals were characterized with testing for resistance to antimicrobial agents, pulsed-field gel electrophoresis (PFGE), and the occurrence of virulence factors. Phenotypic determination of resistance to antimicrobial agents resulted in 20% of E. faecalis isolates showing a triple resistance against chloramphenicol, tetracycline, erythromycin, and seven isolates (two E. faecalis and five E. faecium) exhibiting a multiresistance against five or more antimicrobials. One isolate each of E. faecalis and E. faecium showed vancomycin resistance. All isolates contained at least two of the nine tested virulence genes (agg, gelE, cyl, esp, efaAfs, efaAfm, cpd, cob, and ccf). Phylogenetic analysis of the PFGE profiles identified several small clusters within E. faecalis isolates, one of which included isolates of all three hospitals. Fifty-six (73%) isolates occurred as unique, patient-specific clones. Several PFGE types were associated with shared features in their resistance patterns, indicating spread between and within wards. Finally, enterococci from this study and previous isolates from cheeses were examined by PFGE typing. The comparison of PFGE profiles from human and food isolates resulted in clusters of genetically strong related strains, which suggests high similarities of the enterococcal community composition of these two environments. A possible spread of the enterococcal isolates through the food supply cannot be excluded.
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Affiliation(s)
- S P Templer
- Section of Microbiological and Biotechnological Risks, Swiss Federal Office of Public Health, Schwarzenburgstrasse 165, 3097 Liebefeld, Switzerland
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Occurrence of virulence factors and antibiotic resistances in Enterococcus faecalis and Enterococcus faecium collected from dairy and human samples in North Italy. Food Control 2008. [DOI: 10.1016/j.foodcont.2007.08.019] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bhardwaj A, Malik RK, Chauhan P. Functional and safety aspects of enterococci in dairy foods. Indian J Microbiol 2008; 48:317-25. [PMID: 23100728 PMCID: PMC3476767 DOI: 10.1007/s12088-008-0041-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 02/21/2008] [Indexed: 10/21/2022] Open
Abstract
The genus Enterococcus like other LAB has also been featured in dairy industry for decades due to its specific biochemical traits such as lipolysis, proteolysis, and citrate breakdown, hence contributing typical taste and flavor to the dairy foods. Furthermore, the production of bacteriocins by enterococci (enterocins) is well documented. These technological applications have led to propose enterococci as adjunct starters or protective cultures in fermented foods. Moreover, enterococci are nowadays promoted as probiotics, which are claimed for the maintenance of normal intestinal microflora, stimulation of the immune system and improvement of nutritional value of foods. At the same time, enterococci present an emerging pool of opportunistic pathogens for humans as they cause disease, possess agents for antibiotic resistance, and are frequently armed with potential virulence factors. Because of this "dualistic" nature, the use of enterococci remains a debatable issue. However, based on a long history of safe association of particular enterococci with some traditional food fermentations, the use of such strains appears to bear no particular risk for human health. Abundance of knowledge as well as progress in molecular techniques has, however, enabled exact characterization and safety assessment of strains. Therefore, a balanced evaluation of both, beneficial and undesirable nature of enterococci is required. A clear understanding of their status may, therefore, allow their safe use as a starter, or a probiotic strain. The present review describes the broader insight of the benefits and risks of enterococci in dairy foods and their safety assessment.
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Affiliation(s)
- Arun Bhardwaj
- Microbial Metabolites Laboratory, Dairy Microbiology Division National Dairy Research Institute, Karnal, 132 001 India
| | - R. K. Malik
- Microbial Metabolites Laboratory, Dairy Microbiology Division National Dairy Research Institute, Karnal, 132 001 India
| | - Prashant Chauhan
- Microbial Metabolites Laboratory, Dairy Microbiology Division National Dairy Research Institute, Karnal, 132 001 India
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Sources of enterococci in Idiazábal-type cheese. Int J Food Microbiol 2008; 125:146-52. [DOI: 10.1016/j.ijfoodmicro.2008.03.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 03/06/2008] [Accepted: 03/25/2008] [Indexed: 11/20/2022]
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Aquilanti L, Silvestri G, Zannini E, Osimani A, Santarelli S, Clementi F. Phenotypic, genotypic and technological characterization of predominant lactic acid bacteria in Pecorino cheese from central Italy. J Appl Microbiol 2008; 103:948-60. [PMID: 17897198 DOI: 10.1111/j.1365-2672.2007.03513.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS Identification and biotyping of lactic acid bacteria (LAB) isolated from raw-milk Pecorino cheese manufactured in the Marche region (central Italy) for selection of suitable starter cultures or adjuncts. METHODS AND RESULTS Preliminary characterization with morphological and biochemical assays were undertaken for 112 Gram-positive and catalase-negative isolates. Unequivocal identification of the isolates was obtained through restriction analysis of the amplified 16S rRNA gene and sequencing of 360-380 bp amplicons. Fifty-nine isolates belonging to LAB species generally recognized as safe and potentially utilized as starters or flavour-producing adjuncts were preselected and tested for their acidifying, proteolitic and autolytic activities. Fifty-five of these isolates were also subject to RAPD (randomly amplified polymorphic DNA) fingerprinting and unweighted pair-group method with arithmetic averages (UPGMA) cluster analysis for the estimation of genotypic intra-species variation. As a result, in Pecorino cheese, a heterogeneous lactic acid bacteria population, which includes strains with metabolic characteristics of technological interest, was characterized. CONCLUSIONS The polyphasic approach proposed allows the bacterial ecology of Pecorino cheese to be investigated and allows to assess the potential role of autochthonous LAB strains for the dairy industry. SIGNIFICANCE AND IMPACT OF THE STUDY The great economic importance of Pecorino cheese encouraged a deeper knowledge of its microbiota, which is known to influence the peculiar sensory properties of this cheese, also in view of its exploitation.
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Affiliation(s)
- L Aquilanti
- Department of Food Science, Polytechnic University of Marche, Via Brecce Bianche (Monte Dago), Ancona, Italy
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Pelicioli Riboldi G, Preusser de Mattos E, Guedes Frazzon AP, Alves d'Azevedo P, Frazzon J. Phenotypic and genotypic heterogeneity of Enterococcus species isolated from food in Southern Brazil. J Basic Microbiol 2008; 48:31-7. [PMID: 18247393 DOI: 10.1002/jobm.200700226] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Enterococcus is an important group of lactic acid bacteria (LAB), which inhabits the gastrointestinal tract of humans and animals. These microorganisms can also be found in large groups of foods where they can play a beneficial role during food maturation processes or, conversely, can be used as a food contamination indicator. These microorganisms have an additional importance in various aspects of clinical microbiology. The aim of this study was to investigate and determine the phenotypic and genetic diversity in 55 enterococci isolated from different food sources. Phenotypic characteristics based upon substrate hydrolysis differences were used to identify different Enterococcus species. Analysis of the resultant data divided these species into eight Enterococcus phenotype groups. E. faecalis was the food isolate species with the greatest phenotypic variability. Fifty-five previously isolated Enterococcus strains were re-confirmed as belonging to this genus by PCR techniques. Randomly amplified polymorphic DNA (RAPD-PCR) was used to study the genetic variability using M13 primers and the resultant DNA fragments produced a database of different fingerprints. After statistical analyses of the RAPD-PCR profiles, 42 patterns were obtained and 6 different Enterococcus RAPD clusters (ERC) were identified. Genetic diversity was highest in ERC I, which grouped together approximately 40% of the E. faecium and E. faecalis isolates obtained from dairy products. Samples isolated from meat and vegetables offered the greatest genotype variability. Results of the present study suggest the presence of both phenotypic and genotypic variability within enterococci strains isolated from diverse sources of food common to Southern Brazil.
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Affiliation(s)
- Gustavo Pelicioli Riboldi
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul
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Kongo JM, Ho AJ, Malcata FX, Wiedmann M. Characterization of dominant lactic acid bacteria isolated from São Jorge cheese, using biochemical and ribotyping methods. J Appl Microbiol 2008; 103:1838-44. [PMID: 17953594 DOI: 10.1111/j.1365-2672.2007.03423.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To identify, using phenotypic and genotypic methods, the dominant lactic acid bacteria (LAB) present in São Jorge cheese - one of the 11 Portuguese cheeses currently bearing an Appéllation d'Origine Protegée status. METHODS AND RESULTS A total of 225 isolates from milk, curd and cheeses throughout ripening were identified to the genus level, 108 to the species level and ten to the strain level. Phenotypic methods indicated that lactobacilli, followed by enterococci, were the dominant bacteria. The most frequently isolated species were Lactobacillus paracasei, Lactobacillus rhamnosus, Enterococcus faecalis and Enterococcus faecium. Ribotyping differentiated three L. paracasei, two E. faecalis and one Lactobacillus plantarum types. Enterococcus spp. exhibited the highest esterase and beta-galactosidase activities among all isolates. CONCLUSIONS The dominant LAB in São Jorge cheese are L. paracasei, L. rhamnosus, E. faecalis and E. faecium. Enterococcus likely plays a leading role upon acidification and aroma development in said cheese. SIGNIFICANCE AND IMPACT OF THE STUDY Our results support that a combination of conventional biochemical methods with genotypic methods allows for a thorough characterization and identification of isolates. Despite the limited number of isolates subject to molecular subtyping, a few specific Enterococcus and Lactobacillus strains were found that are promising ones for development of a starter culture. Hence, L. paracasei and E. faecalis are good candidates for a tentative starter culture, designed for manufacturing of São Jorge cheese at large - which takes advantage of actual isolates, in attempts to eventually standardize the quality of said cheese variety.
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Affiliation(s)
- J M Kongo
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, Porto, Portugal
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Purification and characterisation of bacteriocins produced by Enterococcus faecium from Tunisian rigouta cheese. Food Control 2008. [DOI: 10.1016/j.foodcont.2007.03.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Abstract
The aim of this study was to screen two cheese starter cultures and cheese-borne microbial communities with the potential to produce biogenic amines in cheese during ripening. Bacteria of the genera Enterococcus and Lactobacillus and coliform bacteria were isolated from Dutch-type semi-hard cheese at the beginning of the ripening period. Statistically significant counts of bacterial isolates were screened for the presence of specific DNA sequences coding for tyrosine decarboxylase (tyrDC) and histidine decarboxylase (hDC) enzymes. The PCR analysis of DNA from 14 Enterococcus and 3 Lactobacillus isolates confirmed the presence of the targetted DNA sequences. Simultaneously, 13 tyrDC- and 3 hDC-positive isolates were grown in decarboxylase screening medium and this was followed by HPLC analysis of the produced tyramine and histamine. Conventional and molecular taxonomic analyses of the above-mentioned isolates identified the following species: Enterococcus durans (7 strains), Enterococcus faecalis (3 strains), Enterococcus faecium (1 strain), Enterococcus casseliflavus (3 strains), Lactobacillus curvatus (1 strain), Lactobacillus lactis (1 strain) and Lactobacillus helveticus (1 strain). All of the above Enterococcus and two of the Lactobacillus strains originated from contaminating microbial communities. The L. helveticus strain, which was tyrosine decarboxylase-positive and exhibited tyramine production, originated from starter culture 1 used for cheese production. Comparison of partial tyrDC sequences of positive Enterococcus isolates revealed 89% sequence similarity, and that of hDC-positive Lactobacillus isolates revealed 99% sequence similarity.
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Affiliation(s)
- Radka Burdychova
- Department of Food Technology, Mendel University of Agriculture and Forestry in Brno, Brno, Czech Republic.
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Fracalanzza SAP, Scheidegger EMD, Santos PFD, Leite PC, Teixeira LM. Antimicrobial resistance profiles of enterococci isolated from poultry meat and pasteurized milk in Rio de Janeiro, Brazil. Mem Inst Oswaldo Cruz 2007; 102:853-9. [PMID: 18060316 DOI: 10.1590/s0074-02762007005000120] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Accepted: 10/09/2007] [Indexed: 02/06/2023] Open
Abstract
The enterococci are important nosocomial pathogens with a remarkable capacity of expressing resistance to several antimicrobial agents. Their ubiquitous nature and resistance to adverse environmental conditions take account for their ability to colonize different habitats and for their potential for easy spreading through the food chain. In the present study we evaluated the distribution of species and antimicrobial susceptibility among enterococcal isolates recovered from food obtained in retail stores in Rio de Janeiro, Brazil. The following species were identified among 167 isolates obtained from poultry meat and 127 from pasteurized milk: Enterococcus faecalis (62.6%), E. casseliflavus (17.3%), E. durans (6.5%), E. gallinarum (3.0%), E. gilvus (2.4%), E. faecium (2.0%), E. hirae (1.4%), and E. sulfureus (1.0%). The overall percentages of antimicrobial resistant isolates were: 31.2 % to tetracycline, 23.8% to erythromycin, 11.3% to streptomycin, 4.3% to chloramphenicol, 3.9% to gentamicin, 1.4% to norfloxacin, 1.1% to imipenem, 0.7% to ciprofloxacin, nitrofurantoin, and penicillin, and 0.4% to ampicillin. Intermediate resistance was detected in frequencies varying from 0.5% for linezolid to 58.2% for erythromycin. None of the isolates showed resistance to glycopeptides. High-level resistance to aminoglycosides was observed in 13.1% of the isolates. Multiresistance was observed in E. faecalis, E. casseliflavus, E. faecium, E. gallinarum, E. durans and E. gilvus.
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Pimentel LL, Semedo T, Tenreiro R, Crespo MTB, Pintado MME, Malcata FX. Assessment of safety of enterococci isolated throughout traditional Terrincho cheesemaking: virulence factors and antibiotic susceptibility. J Food Prot 2007; 70:2161-7. [PMID: 17900097 DOI: 10.4315/0362-028x-70.9.2161] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Enterococci account for an important fraction of the adventitious microflora of traditional cheeses manufactured in Mediterranean countries from small ruminants' raw milk and play an important role in the development of suitable organoleptic characteristics of the final product. It has been suggested that animals used for food or animals that supply edible products are a reservoir of antibiotic-resistant enterococci. The main purpose of this research effort was thus to identify, to the species level, a total of 73 enterococci with high tolerance to acidic pH and bile salts (as prevailing environmental conditions in the first portion of the gastrointestinal tract), which were previously isolated from the milk feedstock to the final product of Terrincho cheesemaking, and to determine their profiles of antibiotic susceptibility, coupled with the occurrence of specific virulence factors (especially in those that might eventually be claimed to exhibit suitable probiotic and technological performances). Isolates, identified by both API 20 STREP and PCR methods, were found to belong to the following Enterococcus species: E. casseliflavus, E. durans, E. faecalis, E. faecium, and E. gallinarum. Susceptibility of those isolates was observed to most antibiotics tested, whereas none harbored aminoglycoside resistance genes. PCR screenings for cytolysin genes (cylL(L), cylL(s), cylM, cylB, and cylA), surface adhesin genes (efaA(fs), efaA(fm), and esp), the aggregation protein gene (agg), and the extracellular metalloendopeptidase gene (gelE) were performed. All isolates proved negative for cylL(L), cylM, cylB, and agg genes. Both E. faecalis strains were positive for the cell wall-associated protein Esp and the cell wall adhesin efaA(fs), whereas the cell wall adhesin efaA(fm) was detected in 11 of the 12 E. faecium strains. Only one strain possessed the cylL(s) determinant, and another possessed the cylA gene. Incidence of virulence determinants was thus very low; hence, the enterococcal adventitious microflora tested is essentially safe.
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Affiliation(s)
- Lígia L Pimentel
- Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, P-4200-072 Porto, Portugal
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Kagkli D, Vancanneyt M, Vandamme P, Hill C, Cogan T. Contamination of milk by enterococci and coliforms from bovine faeces. J Appl Microbiol 2007; 103:1393-405. [DOI: 10.1111/j.1365-2672.2007.03338.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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