Maria Vieites Diaz

Isolation and typification of histamine-producing Lactobacillus vaginalis strains from cheese

In food, the biogenic amine (BA) histamine is mainly produced by histidine decarboxylation catalysed by microbial histidine decarboxylase. The consumption of foods containing high concentrations of histamine can trigger adverse neurological, gastrointestinal and respiratory reactions. Indeed, histamine is one of the most toxic of all BAs, and is often detected in high concentration in cheese. However, little is known about the microorganisms responsible for its accumulation in this food. In the present work, 25 histamine-producing Lactobacillus vaginalis strains were isolated from a blue-veined cheese (the first time that histamine-producing strains of this species have been isolated from any food). The restriction profiles of their genomes were analysed by PFGE, and seven lineages identified. The presence of the histidine decarboxylase gene (hdcA) was confirmed by PCR. The nucleotide sequence and genetic organisation of the histamine biosynthesis gene cluster (HDC) and its flanking regions are described for a representative strain (L. vaginalis IPLA11050).

Biofilm-Forming Capacity in Biogenic Amine-Producing Bacteria Isolated from Dairy Products

Biofilms on the surface of food industry equipment are reservoirs of potentially food-contaminating bacteria—both spoilage and pathogenic. However, the capacity of biogenic amine (BA)-producers to form biofilms has remained largely unexamined. BAs are low molecular weight, biologically active compounds that in food can reach concentrations high enough to be a toxicological hazard. Fermented foods, especially some types of cheese, accumulate the highest BA concentrations of all. The present work examines the biofilm-forming capacity of 56 BA-producing strains belonging to three genera and 10 species (12 Enterococcus faecalis, 6 Enterococcus faecium, 6 Enterococcus durans, 1 Enterococcus hirae, 12 Lactococcus lactis, 7 Lactobacillus vaginalis, 2 Lactobacillus curvatus, 2 Lactobacillus brevis, 1 Lactobacillus reuteri, and 7 Lactobacillus parabuchneri), all isolated from dairy products. Strains of all the tested species - except for L. vaginalis—were able to produce biofilms on polystyrene and adhered to stainless steel. However, the biomass produced in biofilms was strain-dependent. These results suggest that biofilms may provide a route via which fermented foods can become contaminated by BA-producing microorganisms.

Cardiac complications after laparoscopic large hiatal hernia repair. Is it related with staple fixation of the mesh? -Report of three cases

Introduction Laparoscopic Nissen operation with mesh reinforcement remains being the most popular operation for large hiatal hernia repair. Complications related to mesh placement have been widely described. Cardiac complications are rare, but have a fatal outcome if they are misdiagnosed. Presentation of cases We sought to outline our institutional experience of three patients who developed cardiac complications following a laparoscopic Nissen operation for large hiatal hernia repair. Discussion Laparoscopic hiatoplasty and Nissen fundoplication are safe and effective procedures for the hiatal hernia repair, but they are not exempt from complications. Fixation technique and material used must be taken into account. We have conducted a review of the literature on complications related to these procedures. Conclusion In the differential diagnosis of hemodynamic instability after laparoscopic hiatal hernia repair, cardiac tamponade and other cardiac complications should be considered.

Nucleotide sequence alignment of hdcA from Gram-positive bacteria.

The decarboxylation of histidine -carried out mainly by some gram-positive bacteria- yields the toxic dietary biogenic amine histamine (Ladero et al. 2010 〈10.2174/157340110791233256〉 [1], Linares et al. 2016 〈http://dx.doi.org/10.1016/j.foodchem.2015.11.013〉〉 [2]). The reaction is catalyzed by a pyruvoyl-dependent histidine decarboxylase (Linares et al. 2011 〈10.1080/10408398.2011.582813〉 [3]), which is encoded by the gene hdcA. In order to locate conserved regions in the hdcA gene of Gram-positive bacteria, this article provides a nucleotide sequence alignment of all the hdcA sequences from Gram-positive bacteria present in databases. For further utility and discussion, see 〈http://dx.doi.org/ 10.1016/j.foodcont.2015.11.035〉〉 [4].

Lactobacillus parabuchneri produces histamine in refrigerated cheese at a temperature-dependent rate

This work was funded by the Spanish Ministry of Economy and Competitiveness (AGL2013‐45431‐R and AGL2016‐78708‐R), and by the GRUPIN14‐137 project (which is co‐financed by the Plan for Science, Technology and Innovation of the Principality of Asturias 2013–2017 and European Regional Development Funds)