Capturing yeast associated with grapes and spontaneous fermentations of the Negro Saurí minority variety from an experimental vineyard near León

[EN] ‘Microbial terroir’ relates to the influence of autochthonous yeasts associated with a grape cultivar on the resultant wine. Geographic region, vineyard site and topography, climate and vintage influence the biodiversity of these microbial communities. Current research focus attempts to correlate their ‘microbial fingerprint’ to the sensorial and chemical characteristics of varietal wines from distinct geographical wine regions. This study focuses on the minor red grape variety, Negro Saurí, which has seen a resurgence in the León Appellation of Origin in Spain as a varietal wine. An experimental vineyard at Melgarajo S.A. (42° 15′ 48.68_N 5° 9′ 56.66_W) was sampled over four consecutive vintages, with autochthonous yeasts being isolated from grapes, must and pilot-scale un-inoculated fermentations, and identified by ITS sequencing. Forty-nine isolates belonging to Metschnikowia pulcherrima, Lachancea thermotolerans, Hanseniaspora uvarum and Torulaspora delbrueckii were isolated from grapes and must, and early stages of fermentation dependent on seasonal variation. Saccharomyces cerevisiae predominated throughout fermentation, as a heterogeneous and dynamic population, with seven major biotypes identified amongst 110 isolates across four consecutive vintages. Twenty-four S. cerevisiae isolates representing five strains dominated in two or more vintages. Their persistence through fermentation warrants further validation of their oenological properties as starter cultures.S

Author Correction: Capturing yeast associated with grapes and spontaneous fermentations of the Negro Saurí minority variety from an experimental vineyard near León

[EN] The original version of this Article contained a typographical error in the spelling of the author María-Eva Vallejo-Pascual, which was incorrectly given as María-Eva Pascual-Vallejo. This has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information file.S

Dissemination of Clonal Groups of Brachyspira hyodysenteriae amongst Pig Farms in Spain, and Their Relationships to Isolates from Other Countries

Background: Swine dysentery (SD) is a widespread diarrhoeal disease of pigs caused by infection of the large intestine with the anaerobic intestinal spirochaete Brachyspira hyodysenteriae. Understanding the dynamics of SD, and hence being able to develop more effective measures to counter its spread, depends on the ability to characterise B. hyodysenteriae variants and trace relationships of epidemic strains. Methodology/Principal Findings: A collection of 51 Spanish and 1 Portuguese B. hyodysenteriae isolates was examined using a multilocus sequence typing (MLST) scheme based on the sequences of seven conserved genomic loci. The isolates were allocated to 10 sequence types (STs) in three major groups of descent. Isolates in four of the STs were widely distributed in farms around Spain. One farm was infected with isolates from more than one ST. Sequence data obtained from PubMLST for 111 other B. hyodysenteriae strains from other countries then were included in the analysis. Two of the predominant STs that were found in Spain also were present in other European countries. The 73 STs were arranged in eleven clonal complexes (Cc) containing between 2 and 26 isolates. A population snapshot based on amino acid types (AATs) placed 75% of the isolates from 32 of the 48 AATs into one major cluster. The founder type AAT9 included 22 isolates from 10 STs that were recovered in Spain, Australia, Sweden, Germany, Belgium, the UK, Canada, and the USA. Conclusions/Significance: This MLST scheme provided sufficient resolution power to unambiguously characterise B. hyodysenteriae isolates, and can be recommended as a routine typing tool that rapidly enables comparisons of isolates. Using this method it was shown that some of the main genetic lineages of B. hyodysenteriae in Spain also occurred in other countries, providing further evidence for international transmission. Finally, analysis of AATs appeared useful for deducing putative ancestral relationships between strains

Sero- and genotyping of Salmonella in slaughter pigs, from farm to cutting plant, with a focus on the slaughter process

The objective of this study was to investigate the role of the slaughtering process in Salmonella carcass contamination by typing isolates recovered previously in a double study of the following: (1) a tracking survey from the farm to the slaughterhouse and (2) a survey of the slaughterhouse environment (i.e., lairage area, slaughter line, cutting plant and carcasses).The Salmonella serotypes identified on the carcasses of the 16 tracked batches were frequently linked to lairage, whereas the serotypes detected at the farm, transport or pig-related samples (i.e., caecum content and lymph nodes) were only occasionally detected at the carcass level. Multi-locus variable-number tandem repeats (MLVA) of 77 Salmonella enterica ser. Typhimurium isolates from seven of these batches confirmed the link between the isolates recovered from carcasses and holding pens. Only four of the 16 positive carcasses had profiles previously isolated from lymph nodes or caecal content.In the second part of the study, a total of 131 S. enterica ser. Typhimurium and 74 S. enterica ser. Derby isolates were further characterised by MLVA and Pulsed Field Gel Electrophoresis (PFGE), respectively. The MLVA profiles identified in carcasses varied throughout the working day and were frequently linked to those identified in samples from the slaughter line points collected close in time. PFGE and MLVA profiles identified at lairage were also detected in later processing facilities (i.e., slaughter line and cutting plant) as well as in carcasses. Finally, most of the profiles found at the cutting plants were previously identified in the slaughter line or carcass samples. The results from this study show that Salmonella contamination in pigs entering the slaughterhouse can be attributed to several sources. Typing of isolates by MLVA and PFGE clarified the sources of carcass contamination and improved the accuracy of cross-contamination attributable values. Without obviating the relevant role of infected pigs entering the slaughterhouse, the present study highlights the lairage and slaughtering as important sources of carcass contamination. © 2012 Elsevier B.V.This work was funded by the Ministerio de Agricultura, Pesca y Alimentación, the Ministerio de Ciencia y Tecnología project no. GL2002-04161-C02-01 and the Junta de Castilla y León project no. C.O. C137.s.Peer Reviewe

Phenylacetyl-Coenzyme A Is the True Inducer of the Phenylacetic Acid Catabolism Pathway in Pseudomonas putida U

Aerobic degradation of phenylacetic acid in Pseudomonas putida U is carried out by a central catabolism pathway (phenylacetyl-coenzyme A [CoA] catabolon core). Induction of this route was analyzed by using different mutants specifically designed for this objective. Our results revealed that the true inducer molecule is phenylacetyl-CoA and not other structurally or catabolically related aromatic compounds

Multiple-Locus Variable-Number Tandem-Repeat Analysis of the Swine Dysentery Pathogen, Brachyspira hyodysenteriae▿ †

The spirochete Brachyspira hyodysenteriae is the causative agent of swine dysentery, a severe colonic infection of pigs that has a considerable economic impact in many swine-producing countries. In spite of its importance, knowledge about the global epidemiology and population structure of B. hyodysenteriae is limited. Progress in this area has been hampered by the lack of a low-cost, portable, and discriminatory method for strain typing. The aim of the current study was to develop and test a multiple-locus variable-number tandem-repeat analysis (MLVA) method that could be used in basic veterinary diagnostic microbiology laboratories equipped with PCR technology or in more advanced laboratories with access to capillary electrophoresis. Based on eight loci, and when performed on isolates from different farms in different countries, as well as type and reference strains, the MLVA technique developed was highly discriminatory (Hunter and Gaston discriminatory index, 0.938 [95% confidence interval, 0.9175 to 0.9584]) while retaining a high phylogenetic value. Using the technique, the species was shown to be diverse (44 MLVA types from 172 isolates and strains), although isolates were stable in herds over time. The population structure appeared to be clonal. The finding of B. hyodysenteriae MLVA type 3 in piggeries in three European countries, as well as other, related, strains in different countries, suggests that spreading of the pathogen via carrier pigs is likely. MLVA overcame drawbacks associated with previous typing techniques for B. hyodysenteriae and was a powerful method for epidemiologic and population structure studies on this important pathogenic spirochete