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Frontiers in Microbiology 2022Sliced cooked ham packaged in a modified atmosphere is a popular ready-to-eat product, subjected to abundant microbial contamination throughout its shelf life that can...
Sliced cooked ham packaged in a modified atmosphere is a popular ready-to-eat product, subjected to abundant microbial contamination throughout its shelf life that can lead to deterioration of both sensorial properties and safety. In this study, the microbial load and the chemical-physical features of cooked ham of five producers were monitored for a period of 12 days after the opening of the packages (i.e., the secondary shelf life), during which the products were stored in a domestic refrigerator at 5.2 ± 0.6°C. The sensorial properties presented a perceivable decay after 8 days and became unacceptable after 12 days. High-performance liquid chromatography analysis and solid-phase microextraction coupled with gas chromatography profiling of volatile metabolites indicated that lactic acid, ethanol, acetic acid, acetoin, 3-methyl-1-butanol, and 2-3 butanediol were the main metabolites that characterized the evolution of the analyzed cooked ham. The microbiota was monitored by 16S ribosomal RNA gene profiling and culture-dependent techniques. Already at the opening of packages, all the products presented high microbial load, generally dominated by lactic acid bacteria, with evident differences among the products. The increase of lactic acid bacteria somehow protected samples from abundant contamination by other bacteria, concurring with the evolution of more safe products. This role was exerted by numerous , , and species, among which the most frequently detected were , , , and Some products presented more complex communities that encompassed Proteobacteria such as , , , and less frequently , , and . Opportunistic pathogenic bacteria such as and V sp. were found in small quantities. The yeasts and occurred already at 0 days, whereas various species of (, , , and ) were abundant only after 12 days. These results indicated that the microbiological contaminants overgrowing during the secondary shelf life did not derive from environmental cross-contamination at the opening of the tray but were already present when the packages were opened, highlighting the phases of production up to the packaging as those crucial in managing the safety risk associated to this product.
PubMed: 35350621
DOI: 10.3389/fmicb.2022.842390 -
Journal of Applied Microbiology Nov 2021The complex mycobiota that colonizes traditional fermented sausages plays an important role in the organoleptic properties of such products. The aim of the present study...
AIMS
The complex mycobiota that colonizes traditional fermented sausages plays an important role in the organoleptic properties of such products. The aim of the present study was to investigate fungal diversity and mycotoxin production during maturation of PGI Salame Piemonte.
METHODS AND RESULTS
Casing and meat samples were collected at five sampling times from three different batches produced in the same factory and analysed using culture-dependent and independent approaches. Penicillium nalgiovense, which was deliberately inoculated, and Debaryomyces hansenii were the most dominant taxa in casings. Several other fungi mainly belonging to Penicillium crustosum, Penicillium glabrum, Penicillium nordicum, Cladosporium spp., Candida sake, Candida zeylanoides and Yarrowia divulgata were also identified. The casing mycobiota was compared to that of the meat using a metataxonomic approach and a higher fungal diversity was observed in meat as compared to casings. Mycotoxins and penicillin G were monitored using QTOF LC-MS and only trace amounts of roquefortine C were detected in two batches.
CONCLUSIONS
The present study highlighted the diversity of Salame Piemonte mycobiota and the important contribution of autochthonous fungi to its diversity. The absence of mycotoxins and penicillin G confirmed the high hygienic quality of the studied product regarding fungal and mycotoxin contamination.
SIGNIFICANCE AND IMPACT OF THE STUDY
For the first time, this study provides insights about Salame Piemonte mycobiota, which together with the bacterial microbiota and Salame Piemonte process specifications, are responsible for the product organoleptic properties.
Topics: Candida; Fermentation; Food Microbiology; Meat Products; Mycotoxins; Penicillium; Saccharomycetales
PubMed: 33893697
DOI: 10.1111/jam.15114 -
Journal of Oral Microbiology 2020: Recent studies have reveled the presence of a complex fungal community (mycobiome) in the oral cavity. However, the role of oral mycobiome in dental caries and its...
: Recent studies have reveled the presence of a complex fungal community (mycobiome) in the oral cavity. However, the role of oral mycobiome in dental caries and its interaction with caries-associated bacteria is not yet clear. : Whole-mouth supragingival plaque samples from 30 children (6-10 years old) with no caries, early caries, or advanced caries were sequenced for internal transcribed spacer 2 (ITS-2). The mycobiome profiles were correlated with previously published bacteriome counterparts. Interaction among selected fungal and bacterial species was assessed by co-culture or spent media experiments. : Fungal load was extremely low. and spp. were the most prevalent/abundant taxa. Advanced caries was associated with significantly higher fungal load and prevalence/abundance of and were significantly over-abundant in early caries, while was significantly enriched in caries-free subjects. correlated with and among other caries-associated bacteria, while inversely correlated with caries-associated bacteria. demonstrated inhibitory properties against . : the results substantiate the potential role of the oral mycobiome, primarily species, in dental caries. Inter-kingdom correlations and inhibition of by are worth further investigation.
PubMed: 32158514
DOI: 10.1080/20002297.2020.1729305 -
Nanomaterials (Basel, Switzerland) Dec 2022The present paper described the first green synthesis of silver nanoparticles (AgNPs) from the extremophile plant . The characterization of the biosynthesized silver...
The present paper described the first green synthesis of silver nanoparticles (AgNPs) from the extremophile plant . The characterization of the biosynthesized silver nanoparticles was carried out by using UV-Vis, FTIR and STM analysis. The antioxidant, antidiabetic and antimicrobial properties were also reported. The newly described AgNPs were spherical in shape and had a size of 35-55 nm. The lowest IC50 values measured by the DPPH assay indicate the superior antioxidant behavior of our AgNPs as opposed to ascorbic acid. The silver nanoparticles show high antidiabetic activity determined by the inhibitory effect of α amylase as compared to the standard Acarbose. Moreover, the AgNPs inhibit bacterial growth owing to a bactericidal effect with the MIC values varying from 0.017 to 1.7 µg/mL. The antifungal action was evaluated against , , , and non-dermatophytic onychomycosis fungi. A strong inhibitory effect on Candida factors' virulence was observed as proteinase and phospholipase limitations. In addition, the microscopic observations show that the silver nanoparticles cause the eradication of blastospores and block filamentous morphogenesis. The combination of the antioxidant, antimicrobial and antidiabetic behaviors of the new biosynthesized silver nanoparticles highlights their promising use as natural phytomedicine agents.
PubMed: 36616010
DOI: 10.3390/nano13010100 -
The ileal fungal microbiota is altered in Crohn's disease and is associated with the disease course.Frontiers in Medicine 2022Fungal microbiota's involvement in the pathogenesis of Crohn's disease (CD) is incompletely understood. The terminal ileum is a predilection site both for primary...
INTRODUCTION
Fungal microbiota's involvement in the pathogenesis of Crohn's disease (CD) is incompletely understood. The terminal ileum is a predilection site both for primary involvement and recurrences of CD. We, therefore, assessed the mucosa-associated mycobiota in the inflamed and non-inflamed ileum in patients with CD.
METHODS
The mucosa-associated mycobiota was assessed by ITS2 sequencing in a total of 168 biopsies sampled 5 and 15 cm proximal of the ileocecal valve or ileocolic anastomosis in 44 CD patients and 40 healthy controls (HC). CD patients with terminal ileitis, with endoscopic inflammation at 5 cm and normal mucosa at 15 cm and no history of upper CD involvement, were analyzed separately. The need for additional CD treatment the year following biopsy collection was recorded.
RESULTS
CD patients had reduced mycobiota evenness, increased Basidiomycota/Ascomycota ratio, and reduced abundance of Chytridiomycota compared to HC. The mycobiota of CD patients were characterized by an expansion of and a depletion of , along with increased abundances of and . was associated with the need for treatment escalation during follow-up. Current anti-TNF treatment was associated with lower abundances of Basidiomycota. The alpha diversity of the inflamed and proximal non-inflamed mucosa within the same patients was similar. However, the inflamed mucosa had a more dysbiotic composition with increased abundances of and reduced abundances of and .
CONCLUSIONS
The ileal mucosa-associated mycobiota in CD patients is altered compared to HC. The mycobiota in the inflamed and proximal non-inflamed ileum within the same patients harbor structural differences which may play a role in the CD pathogenesis. Increased abundance of was associated with an unfavorable disease course.
PubMed: 36237548
DOI: 10.3389/fmed.2022.868812 -
Saudi Medical Journal Jul 2016To determine the species incidence and susceptibility pattern to 9 antifungal agents of yeasts isolated from various clinical specimens of colonized or infected patients...
OBJECTIVES
To determine the species incidence and susceptibility pattern to 9 antifungal agents of yeasts isolated from various clinical specimens of colonized or infected patients treated in the coronary and surgical intensive care units (ICU).
METHODS
A total of 421 ICU patients were treated at the Cardiology Institute, Istanbul University, Istanbul, Turkey between June 2013 and May 2014, and 44 Candida species were isolated from blood, urine, endotracheal aspiration fluid, sputum, and wounds of 16 ICU patients. Identification of Candida was performed using CHROMagar. Antifungal susceptibility was determined by a Sensititre YeastOne colorimetric microdilution panel.
RESULTS
Candida albicans (C. albicans) was the most commonly observed microorganism 23 (54%); the other microorganisms isolated were Candida tropicalis 12 (27%), Candida glabrata 5 (11%), Candida parapsilosis 1 (2%), Candida lusitaniae 1 (2%), Candida sake 1 (2%), and Geotrichum capitatum 1 (2%). All isolates were susceptible to amphotericin B and 5-flucytosine. Geotrichum capitatum excepted, the other isolates were also susceptible to anidulafungin, micafungin, and caspofungin. Candida parapsilosis was found to be susceptible to all the studied antifungals. High MIC rates for azole group of antifungal drugs were found for C. albicans, C. tropicalis, and C. glabrata. The rate of colonisation was 3.8% (16/421). Only 0.7% (3/421) patients out of a total of 421 developed candidemia.
CONCLUSION
We found that the yeast colonization and infection rates of patients in our ICUs are very low. Candida albicans is still the most common species. We detected a decreasing susceptibility to azole compounds.
Topics: Aged; Antifungal Agents; Candida; Female; Humans; Male; Microbial Sensitivity Tests
PubMed: 27381534
DOI: 10.15537/smj.2016.7.13412 -
Children (Basel, Switzerland) Feb 2022Dental caries is one of the most common diseases-both in adults and children-that occurs due to the demineralization of enamel and dentine by the organic acids formed... (Review)
Review
Dental caries is one of the most common diseases-both in adults and children-that occurs due to the demineralization of enamel and dentine by the organic acids formed from bacteria present in dental plaques through anaerobic metabolism of dietary sugars. The aim of this article is to provide a guideline to assess the risk of caries by looking for the main factors involved. Literature research was performed for studies that analyzed the factors most involved in the development of child caries, such as poor oral hygiene, bad eating habits (or food disorders), and an alteration of the oral bacterial flora-with an increase of spp., spp., , , and . It is therefore essential to assess the risk of caries in children, based on the assessment of risk factors, in order to be able to establish preventive and/or therapeutic approaches that will reduce or stop the development of dental caries. The use of fluoride products, products made from casein phosphopeptide-amorphous calcium phosphate, substituted zinc biomimetic hydroxyapatite products, or products containing self-assembling oligopeptide SAP-P-4 are useful. In terms of the clinical approach, a communicative approach should be added to learn about the eating habits and the oral hygiene habits of the child and parents; in addition, the use of a simple method to frame the factors involved, and subsequently establish the risk of carious lesions in the child, allows the reduction of the DMFT (Decayed Missing Filled Teeth) or ICDAS (International Caries Detection and Assessment System) index on large scales.
PubMed: 35204983
DOI: 10.3390/children9020262 -
Animals : An Open Access Journal From... Jun 2023Climate changes cause a dramatical increase in the ice-free season in the Arctic, forcing polar bears ashore, closer to human settlements associated with new and...
Climate changes cause a dramatical increase in the ice-free season in the Arctic, forcing polar bears ashore, closer to human settlements associated with new and non-natural food objects. Such a diet may crucially transform the intestinal microbiome and metabolism of polar bears. The aim of this study was to characterize changes in the gut bacterial and fungal communities resulting from the transition to anthropogenic food objects by the means of 16S and ITS metabarcoding. Thus, rectal samples from 16 wild polar bears from the Kara-Barents subpopulation were studied. Human waste consuming resulted in a significant increase in the relative abundance of fermentative bacteria (Lactobacillaceae, Leuconostocaceae, and Streptococcaceae) and a decrease in proteolytic Enterobacteriaceae. However, the alpha-diversity parameters remained similar. Also, for the first time, the composition of the fungal community of the polar bear intestine was determined. Diet change is associated with the displacement of eurybiontic fungi (, , (), and ) by opportunistic , , and . Feeding on human waste does not cause any signs of dysbiosis and probably leads to adaptive changes in the bacterial microbiome. However, the emergence of fungal facultative pathogens increases the risk of infections.
PubMed: 37443865
DOI: 10.3390/ani13132067 -
Microbial Biotechnology Sep 2020In winemaking, the use of alternative yeast starters is becoming increasingly popular. They contribute to the diversity and complexity of wine sensory features and are...
In winemaking, the use of alternative yeast starters is becoming increasingly popular. They contribute to the diversity and complexity of wine sensory features and are typically used in combination with Saccharomyces cerevisiae, to ensure complete fermentation. This practice has drawn the interest on interactions between different oenological yeasts, which are also relevant in spontaneous and conventional fermentations, or in the vineyard. Although several interactions have been described and some mechanisms have been suggested, the possible involvement of extracellular vesicles (EVs) has not yet been considered. This work describes the production of EVs by six wine yeast species (S. cerevisiae, Torulaspora delbrueckii, Lachancea thermotolerans, Hanseniaspora uvarum, Candida sake and Metschnikowia pulcherrima) in synthetic grape must. Proteomic analysis of EV-enriched fractions from S. cerevisiae and T. delbrueckii showed enrichment in glycolytic enzymes and cell-wall-related proteins. The most abundant protein found in S. cerevisiae, T. delbrueckii and L. thermotolerans EV-enriched fractions was the enzyme exo-1,3-β-glucanase. However, this protein was not involved in the here-observed negative impact of T. delbrueckii extracellular fractions on the growth of other yeast species. These findings suggest that EVs may play a role in fungal interactions during wine fermentation and other aspects of wine yeast biology.
Topics: Candida; Extracellular Vesicles; Fermentation; Hanseniaspora; Metschnikowia; Phylogeny; Proteomics; Saccharomyces cerevisiae; Saccharomycetales; Vitis; Wine
PubMed: 32578397
DOI: 10.1111/1751-7915.13614 -
Microbiology Spectrum Feb 2023Microorganisms are key mediators of interactions between insect herbivores and their host plants. Despite a substantial interest in studying various aspects of these...
Microorganisms are key mediators of interactions between insect herbivores and their host plants. Despite a substantial interest in studying various aspects of these interactions, temporal variations in microbiomes of woody plants and their consumers remain understudied. In this study, we investigated shifts in the microbiomes of leaf-mining larvae (Insecta: Lepidoptera) and their host trees over one growing season in a deciduous temperate forest. We used 16S and ITS2 rRNA gene metabarcoding to profile the bacterial and fungal microbiomes of leaves and larvae. We found pronounced shifts in the leaf and larval microbiota composition and richness as the season progressed, and bacteria and fungi showed consistent patterns. The quantitative similarity between leaf and larval microbiota was very low for bacteria (~9%) and decreased throughout the season, whereas fungal similarity increased and was relatively high (~27%). In both leaves and larvae, seasonality, along with host taxonomy, was the most important factor shaping microbial communities. We identified frequently occurring microbial taxa with significant seasonal trends, including those more prevalent in larvae (Streptococcus, Candida sake, Debaryomyces prosopidis, and Neoascochyta europaea), more prevalent in leaves (, Seimatosporium quercinum, Curvibasidium cygneicollum, , Ceramothyrium carniolicum, and Mycosphaerelloides madeirae), and frequent in both leaves and larvae (bacterial strain P3OB-42, , , Acinetobacter, , and Botrytis cinerea). Our results highlight the importance of considering seasonality when studying the interactions between plants, herbivorous insects, and their respective microbiomes, and illustrate a range of microbial taxa persistent in larvae, regardless of their occurrence in the diet. Leaf miners are endophagous insect herbivores that feed on plant tissues and develop and live enclosed between the epidermis layers of a single leaf for their entire life cycle. Such close association is a precondition for the evolution of more intimate host-microbe relationships than those found in free-feeding herbivores. Simultaneous comparison of bacterial and fungal microbiomes of leaves and their tightly linked consumers over time represents an interesting study system that could fundamentally contribute to the ongoing debate on the microbial residence of insect gut. Furthermore, leaf miners are ideal model organisms for interpreting the ecological and evolutionary roles of microbiota in host plant specialization. In this study, the larvae harbored specific microbial communities consisting of core microbiome members. Observed patterns suggest that microbes, especially bacteria, may play more important roles in the caterpillar holobiont than generally presumed.
Topics: Animals; Mycobiome; Larva; Seasons; Bacteria; Diet
PubMed: 36629441
DOI: 10.1128/spectrum.03160-22