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Folia Microbiologica Apr 2022This work aimed to identify the key members of the bacterial community growing on common carp (Cyprinus carpio) fillets during chilled storage with next-generation...
This work aimed to identify the key members of the bacterial community growing on common carp (Cyprinus carpio) fillets during chilled storage with next-generation sequencing (NGS) and cultivation-dependent methods. Carp fillets were stored for 96 h at 2 °C and 6 °C with and without a vacuum package, and an additional frozen-thawed storage experiment was set for 120 days. Community profiles of the initial and stored fish samples were determined by amplicon sequencing. Conventional microbial methods were used parallelly for the enumeration and cultivation of the dominant members of the microbial community. Cultivated bacteria were identified with 16S rRNA sequencing and the MALDI-TOF MS method. Based on our results, the vacuum package greatly affected the diversity and composition of the forming microbial community, while temperature influenced the cell counts and consequently the microbiological criteria for shelf-life of the examined raw fish product. Next-generation sequencing revealed novel members of the chilled flesh microbiota such as Vagococcus vulneris or Rouxiella chamberiensis in the vacuum-packed samples. With traditional cultivation, 161 bacterial strains were isolated and identified at the species level, but the identified bacteria overlapped with only 45% of the dominant operational taxonomic units (OTUs) revealed by NGS. Next-generation sequencing is a promising and highly reliable tool recommended to reach a higher resolution of the forming microbial community of stored fish products. Knowledge of the initial microbial community of the flesh enables further optimization and development of processing and storage technology.
Topics: Animals; Bacteria; Carps; Food Microbiology; Food Storage; Microbiota; RNA, Ribosomal, 16S; Seafood
PubMed: 34877630
DOI: 10.1007/s12223-021-00935-4 -
Parasites & Vectors Dec 2021As a pervasive insect that transmits a variety of pathogens to humans and animals, the housefly has abundant and diverse microbial communities in its intestines. These...
BACKGROUND
As a pervasive insect that transmits a variety of pathogens to humans and animals, the housefly has abundant and diverse microbial communities in its intestines. These gut microbes play an important role in the biology of insects and form a symbiotic relationship with the host insect. Alterations in the structure of the gut microbial community would affect larval development. Therefore, it is important to understand the mechanism regulating the influence of specific bacteria on the development of housefly larvae.
METHODS
For this study we selected the intestinal symbiotic bacterium Enterobacter hormaechei, which is beneficial to the growth and development of housefly larvae, and used it as a probiotic supplement in larval feed. 16S rRNA gene sequencing technology was used to explore the effect of E. hormaechei on the intestinal flora of housefly larvae, and plate confrontation experiments were performed to study the interaction between E. hormaechei and intestinal microorganisms.
RESULTS
The composition of the gut microflora of the larvae changed after the larvae were fed E. hormaechei, with the abundance of Pseudochrobactrum, Enterobacter and Vagococcus increasing and that of Klebsiella and Bacillus decreasing. Analysis of the structure and interaction of larval intestinal flora revealed that E. hormaechei inhibited the growth of harmful bacteria, such as Pseudomonas aeruginosa, Providencia stuartii and Providencia vermicola, and promoted the reproduction of beneficial bacteria.
CONCLUSIONS
Our study has explored the influence of specific beneficial bacteria on the intestinal flora of houseflies. The results of this study reveal the important role played by specific beneficial bacteria on the development of housefly larvae and provide insight for the development of sustained biological agents for housefly control through interference of gut microbiota.
Topics: Animals; Enterobacter; Female; Gastrointestinal Microbiome; Houseflies; Humans; Intestines; Larva; Male; Probiotics; Symbiosis
PubMed: 34876203
DOI: 10.1186/s13071-021-05053-1 -
Foods (Basel, Switzerland) Oct 2021In this study, high-throughput sequencing and culture-dependent and HPLC methods were used to investigate the contribution and regulation of biogenic amines (BAs) by...
In this study, high-throughput sequencing and culture-dependent and HPLC methods were used to investigate the contribution and regulation of biogenic amines (BAs) by dominant microorganisms during fish sauce fermentation. The results showed that the microbial composition constantly changed with the fermentation of fish sauce. (40.65%), (9.23%), (2.20%), (1.80%), (0.98%), (0.94%) and (0.16%) were the dominant microflora in fish sauce. The content of BAs gradually increased as the fermentation progressed. After 12 months of fermentation, the histamine content (55.59 mg/kg) exceeded the toxic dose recommended by the Food and Drug Administration (FDA). Correlation analysis showed that dominant microorganisms have a great contribution to the accumulation of BAs. By analyzing the BA production capacity of dominant isolates, the accumulation of BAs in fish sauce might be promoted by and . Moreover, four strains with high BA reduction ability were screened out of 44 low BA-producing dominant strains, and their influence on BA accumulation in fermented foods was determined. Results demonstrated that 5-5 and JCM 2418 might be the potential starters for BA control. The present study provided a new idea for the control of BAs in fermented foods.
PubMed: 34828853
DOI: 10.3390/foods10112572 -
Biomedical and Environmental Sciences :... Oct 2021
Topics: Animals; China; Chiroptera; Drug Resistance, Bacterial; Enterococcaceae; Genotype; Gram-Positive Bacterial Infections; Phenotype; Virulence; Whole Genome Sequencing
PubMed: 34782051
DOI: 10.3967/bes2021.114 -
Microorganisms Oct 2021Lactic acid bacteria (LAB) are probiotic candidates that may restore the balance of microbiota populations in intestinal microbial ecosystems by controlling pathogens...
Lactic acid bacteria (LAB) are probiotic candidates that may restore the balance of microbiota populations in intestinal microbial ecosystems by controlling pathogens and thereby promoting host health. The goal of this study was to isolate potential probiotic LAB strains and characterize their antimicrobial abilities against pathogens in intestinal microbiota. Among 54 LAB strains isolated from fermented products, five LAB strains (NSMJ15, NSMJ16, NSMJ23, NSMJ42, and NFFJ04) were selected as potential probiotic candidates based on in vitro assays of acid and bile salt tolerance, cell surface hydrophobicity, adhesion to the intestinal epithelium, and antagonistic activity. Phylogenetic analysis based on 16S rRNA genes showed that they have high similarities of 99.58-100% to strains NSMJ15 and NFFJ04, NSMJ16, NSMJ23, and NSMJ42. To characterize their antimicrobial abilities against pathogens in intestinal microbiota, the impact of cell-free supernatant (CFS) treatment in 10% (/) fecal suspensions prepared using pooled cattle feces was investigated using in vitro batch cultures. Bacterial community analysis using rRNA amplicon sequencing for control and CFS-treated fecal samples at 8 and 16 h incubation showed the compositional change after CFS treatment for all five LAB strains. The changed compositions were similar among them, but there were few variable increases or decreases in some bacterial groups. Interestingly, as major genera that could exhibit pathogenicity and antibiotic resistance, the members of , , , , and were decreased at 16 h in all CFS-treated samples. Species-level classification suggested that the five LAB strains are antagonistic to gut pathogens. This study showed the probiotic potential of the five selected LAB strains; in particular, their antimicrobial properties against pathogens present in the intestinal microbiota. These strains would therefore seem to play an important role in modulating the intestinal microbiome of the host.
PubMed: 34683462
DOI: 10.3390/microorganisms9102141 -
Food Science and Biotechnology Sep 2021Sufu is a common solid-state traditional fermented food made from soybean. Huase sufu is a typical type found in several provinces of China, especially in Hubei....
UNLABELLED
Sufu is a common solid-state traditional fermented food made from soybean. Huase sufu is a typical type found in several provinces of China, especially in Hubei. However, little is known about the bacterial community. High-throughput sequencing technology revealed that the dominant taxa at phylum level were: Firmicutes, Proteobacteria and Bacteroides, and at the genus level were: , , , etc. Additionally, LEfSe revealed that compared with the bacterial community of red sufu and white sufu, the biomarker genera for both huase sufu were , and . Moreover, there were twenty-eight hubs for the huase sufu samples, and four of them were dominant genera: , , , . These results provide a new insight into our understanding of the bacterial diversity of huase sufu, and will facilitate the isolation, screening, and development potential bacterial strains for production of huase sufu.
SUPPLEMENTARY INFORMATION
The online version contains supplementary material available at 10.1007/s10068-021-00963-3.
PubMed: 34603822
DOI: 10.1007/s10068-021-00963-3 -
Frontiers in Microbiology 2021Diuron (DUR) is a phenylurea herbicide widely used for the effective control of most annual and perennial weeds in farming areas. The extensive use of DUR has led to its... (Review)
Review
Diuron (DUR) is a phenylurea herbicide widely used for the effective control of most annual and perennial weeds in farming areas. The extensive use of DUR has led to its widespread presence in soil, sediment, and aquatic environments, which poses a threat to non-target crops, animals, humans, and ecosystems. Therefore, the removal of DUR from contaminated environments has been a hot topic for researchers in recent decades. Bioremediation seldom leaves harmful intermediate metabolites and is emerging as the most effective and eco-friendly strategy for removing DUR from the environment. Microorganisms, such as bacteria, fungi, and actinomycetes, can use DUR as their sole source of carbon. Some of them have been isolated, including organisms from the bacterial genera , , , , , , and and fungal genera , , , , , , and A number of studies have investigated the toxicity and fate of DUR, its degradation pathways and metabolites, and DUR-degrading hydrolases and related genes. However, few reviews have focused on the microbial degradation and biochemical mechanisms of DUR. The common microbial degradation pathway for DUR is transformation to 3,4-dichloroaniline, which is then metabolized through two different metabolic pathways: dehalogenation and hydroxylation, the products of which are further degraded cooperative metabolism. Microbial degradation hydrolases, including PuhA, PuhB, LibA, HylA, Phh, Mhh, and LahB, provide new knowledge about the underlying pathways governing DUR metabolism. The present review summarizes the state-of-the-art knowledge regarding (1) the environmental occurrence and toxicity of DUR, (2) newly isolated and identified DUR-degrading microbes and their enzymes/genes, and (3) the bioremediation of DUR in soil and water environments. This review further updates the recent knowledge on bioremediation strategies with a focus on the metabolic pathways and molecular mechanisms involved in the bioremediation of DUR.
PubMed: 34475856
DOI: 10.3389/fmicb.2021.686509 -
Life (Basel, Switzerland) Jul 2021Knowledge of the composition of the gut microbiota in freshwater fish living in their natural habitat has taxonomic and ecological importance. Few reports have been...
Knowledge of the composition of the gut microbiota in freshwater fish living in their natural habitat has taxonomic and ecological importance. Few reports have been produced on the composition of the gut microbiota and on the presence of LAB in the intestines of freshwater fish that inhabit river environments. In this study, we investigated the LAB community that was present in the gastrointestinal tract (GIT) of Mediterranean trout () that colonized the Biferno and Volturno rivers of the Molise region (Italy). The partial 16S rRNA gene sequences of these strains were determined for the species-level taxonomic placement. The phylogenetic analysis revealed that the isolated LABs belonged to seven genera ( and ). The study of the enzymatic activities showed that these LABs could contribute to the breakdown of polysaccharides, proteins, and lipids. In future studies, a greater understanding of how the LABs act against pathogens and trigger the fish immune response may provide practical means to engineer the indigenous fish microbiome and enhance disease control and fish health.
PubMed: 34357039
DOI: 10.3390/life11070667 -
Enfermedades Infecciosas Y... 2021An increase in recent years in the isolation of Vagococcus spp. is suggestive of emerging infection by this pathogen in our hospital. (Review)
Review
INTRODUCTION
An increase in recent years in the isolation of Vagococcus spp. is suggestive of emerging infection by this pathogen in our hospital.
METHODS
Prospective, descriptive study.
PERIOD
July 2014-January 2019. Phenotypic identification of 15 isolates of Vagococcus spp. was performed by conventional biochemical tests, automated methodology and mass spectrometry (MALDI-TOF MS). Molecular identification was achieved by sequencing the 16S rRNA gene. The Vitek™ 2C automated system was used to test antibiotic susceptibility.
RESULTS
The molecular method identified 11 Vagococcus fluvialis, one Vagococcus lutrae and three Vagococcus spp. MALDI-TOF MS facilitated the rapid recognition of the genus. The most active antibiotics were ampicillin, trimethoprim/sulfamethoxazole, vancomycin, teicoplanin and linezolid. Most of the cases of isolation were associated with skin and soft tissue or osteoarticular infections in patients with diabetes.
CONCLUSION
This article is the most extensive review of cases of Vagococcus spp. infection reported in the literature and highlights the microbiological and clinical aspects of this pathogen.
Topics: Enterococcaceae; Humans; Prospective Studies; RNA, Ribosomal, 16S
PubMed: 34353510
DOI: 10.1016/j.eimce.2021.05.002 -
Food Science & Nutrition Jul 2021According to the appearance and technology, traditional fermented Douchi can be divided into dried Douchi and wet Douchi. However, there are few reports on the...
According to the appearance and technology, traditional fermented Douchi can be divided into dried Douchi and wet Douchi. However, there are few reports on the difference of bacterial community structure between them or the influence of bacterial community on product flavor. In this study, high-throughput sequencing technology and electronic nose were used to measure the bacterial diversity and flavor of 40 Douchi samples, and the correlation between them was explored by multivariate statistical means combined with COG database. Results showed that the cumulative average relative abundance of Firmicutes and Proteobacteria in the samples was as high as 95.93%, and the former was the core bacteria phylum. On the whole, the dominant bacteria in Douchi were (50.67%), (14.07%), (2.54%), (1.61%), (1.46%), (1.26%), (1.24%), and (1.19%). LEfSe analysis indicated that can be used as a biomarker in dried fermented soybeans. Meanwhile, dried samples contained more intensive aromatic substances, but were significantly lower in W6S (selectivity to hydrogen) and W3S (methane-aliph) compared with the wet samples. and were helpful to the formation of aromatic flavor in Douchi, but and were the opposite. Gene and microbial phenotypic prediction showed that microorganisms in dried Douchi use protein more efficiently, while in wet Douchi, microbial energy metabolism was more vigorous. The pathogenic potential of microorganisms in dried samples was higher than that in wet. This study can sound the alarm for improving the safety of home-brewed Douchi and provide guidance for the subsequent screening of strains that enhance the flavor of fermented soybeans.
PubMed: 34262706
DOI: 10.1002/fsn3.2280