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Frontiers in Microbiology 2020Because of the nutritional ecology of dung- and carrion-feeding, bacteria are the integral part of life cycle. Nevertheless, the disinfected larvae of the blowfly are...
Because of the nutritional ecology of dung- and carrion-feeding, bacteria are the integral part of life cycle. Nevertheless, the disinfected larvae of the blowfly are applied to treat human chronic wounds in a biosurgery named maggot debridement therapy (MDT). To realize the effects of location/diet on the gut bacteria, to infer the role of bacteria in the blowfly ecology plus in the MDT process, and to disclose bacteria circulating horizontally in and vertically between generations, bacterial communities associated with specimens from various sources were investigated using culture-based and culture-independent methods. In total, 265 bacteria, including 20 families, 28 genera, and 40 species, were identified in many sources of the . Culture-dependent method identified a number of 144 bacterial isolates, including 21 species, in flies reared in an insectary; specimens were collected from the field, and third-instar larvae retrieved from chronic wounds of patients. Metagenetic approach exposed the occurrences of 121 operational taxonomic units comprising of 32 bacterial species from immature and adult stages of . Gammaproteobacteria was distinguished as the dominant class of bacteria by both methods. Bacteria came into the life cycle of over the foods and transovarially infected eggs. , , species, , and were exchanged among individuals via transstadial transmission. Factors, including diets, feeding status, identification tool, gut compartment, and life stage, governed the bacteria species. Herein, we reemphasized that is thoroughly connected to the bacteria both in numerous gut compartments and in different life stages. Among all, transstadially transmitted bacteria are underlined, indicating the lack of antagonistic effect of the larval excretions/secretions on these resident bacteria. While the culture-dependent method generated useful data on the viable aerobic gut bacteria, metagenomic method enabled us to identify bacteria directly from the tissues without any need for cultivation and to facilitate the identification of anaerobic and unculturable bacteria. These findings are planned to pave the way for further research to determine the role of each bacterial species/strain in the insect ecology, as well as in antimicrobial, antibiofilm, anti-inflammatory, and wound healing activities.
PubMed: 32322242
DOI: 10.3389/fmicb.2020.00505 -
The Science of the Total Environment Jun 2020Strains of the environmental bacterium Myroides odoratimimus can cause human infections. However, treating M. odoratimimus infections can be difficult because of...
Strains of the environmental bacterium Myroides odoratimimus can cause human infections. However, treating M. odoratimimus infections can be difficult because of multidrug resistance in this organism. In this study, we isolated strain M. odoratimimus G13 from pastureland in Tibet, China. The minimum inhibitory concentration analysis suggested that strain G13 has resistance to multiple antibiotics, with an MIC for tetracycline of 168 mg/L. Whole-genome sequencing and bioinformatic analysis revealed that the genome of G13 was rich in virulence factor-encoding genes and antibiotic resistance genes (ARGs). The mobilizable genomic island MGI1313 was also identified and characterized, and six resistance genes related to four types of antibiotics were annotated in MGI1313. Conjugation assays indicated that MGI1313 could be transferred from G13 to Escherichia coli 25DN by horizontal gene transfer, resulting in multidrug-resistant E. coli conjugants. In conclusion, multidrug-resistant M. odoratimimus G13 and the mobility of MGI1313 raise the risk of difficult-to-treat bacterial infections and should be under close surveillance.
Topics: Anti-Bacterial Agents; China; Drug Resistance, Multiple, Bacterial; Escherichia coli; Flavobacteriaceae; Flavobacteriaceae Infections; Genomic Islands; Humans; Tibet
PubMed: 32217404
DOI: 10.1016/j.scitotenv.2020.137970 -
Acta Pharmaceutica Sinica. B Feb 2020The progression of hyperuricemia disease is often accompanied by damage to renal function. However, there are few studies on hyperuricemia nephropathy, especially its...
The progression of hyperuricemia disease is often accompanied by damage to renal function. However, there are few studies on hyperuricemia nephropathy, especially its association with intestinal flora. This study combines metabolomics and gut microbiota diversity analysis to explore metabolic changes using a rat model as well as the changes in intestinal flora composition. The results showed that amino acid metabolism was disturbed with serine, glutamate and glutamine being downregulated whilst glycine, hydroxyproline and alanine being upregulated. The combined glycine, serine and glutamate could predict hyperuricemia nephropathy with an area under the curve of 1.00. Imbalanced intestinal flora was also observed. , , , , and other conditional pathogens increased significantly in the model group, while and , the short-chain fatty acid producing bacteria, declined greatly. At phylum, family and genus levels, disordered nitrogen circulation in gut microbiota was detected. In the model group, the uric acid decomposition pathway was enhanced with reinforced urea liver-intestine circulation. The results implied that the intestinal flora play a vital role in the pathogenesis of hyperuricemia nephropathy. Hence, modulation of gut microbiota or targeting at metabolic enzymes, , urease, could assist the treatment and prevention of this disease.
PubMed: 32082971
DOI: 10.1016/j.apsb.2019.10.007 -
The Journal of Antimicrobial... Jun 2020To report a novel tigecycline resistance gene, tet(X6), and its variants in four bacterial species isolated from chickens and pigs in China.
OBJECTIVES
To report a novel tigecycline resistance gene, tet(X6), and its variants in four bacterial species isolated from chickens and pigs in China.
METHODS
WGS was conducted to identify the suspected resistance genes in the tigecycline-resistant Myroides phaeus 18QD1AZ29W. Functional cloning, homology modelling and molecular docking were performed to compare the function with other Tet(X) variants. Retrospective screening for tet(X6) was conducted for 80 isolates in our WGS data collection, and all genomic environments of tet(X6)-positive isolates were analysed.
RESULTS
The tigecycline-resistant M. phaeus 18QD1AZ29W isolated from a pig farm in Shandong in 2018 was positive for tet(X2) and a novel tet(X) gene, designated tet(X6). Tet(X6) could increase the MICs of all tested tetracyclines/glycylcyclines for Escherichia coli only 2- to 4-fold, which was possibly due to a lower tetracycline binding capacity of Tet(X6) compared with that of other Tet(X) variants. Retrospective screening showed that seven other isolates (7/80, 8.8%), comprising four Proteus spp. and three Acinetobacter spp. from chickens and pigs in Shandong and Guangdong, were positive for three different variants of tet(X6). The analysis of the genomic environment revealed that two tet(X6)-positive isolates from M. phaeus and Proteus cibarius, respectively, contained ISCR2, which may play a role in tet(X6) transmission.
CONCLUSIONS
This study identified a novel type of tigecycline resistance gene, tet(X6), in Myroides, Acinetobacter and Proteus from chickens and swine. Tet(X6) conferred lower tetracycline/glycylcycline MICs than other Tet(X) variants, and ISCR2 may play a role in the transmission of tet(X6).
Topics: Acinetobacter; Animals; Anti-Bacterial Agents; Chickens; China; Flavobacteriaceae; Microbial Sensitivity Tests; Molecular Docking Simulation; Proteus; Retrospective Studies; Swine; Tetracycline Resistance; Tigecycline
PubMed: 32068864
DOI: 10.1093/jac/dkaa037 -
IDCases 2020We report the first case of isolated from blood, causing bacteremia in an immunocompromised patient using the automated MicroScan Walk Away 96 system, followed by...
We report the first case of isolated from blood, causing bacteremia in an immunocompromised patient using the automated MicroScan Walk Away 96 system, followed by bacterial identification by amplification-sequencing of the 16S rDNA. The sequences obtained were compared with the reference sequence of the BLAST ® platform - National Library of Medicine, USA, and the isolation was identified as strain with 99.67 % identity in Blast report. In the literature we did not find previous reported cases of infections by this bacterium, however its pathogenic role is still controversial; therefore, this isolation alerts us to carry out an exhaustive surveillance of other possible acquisition routes.
PubMed: 32021799
DOI: 10.1016/j.idcr.2020.e00695 -
Infection and Drug Resistance 2020The genus are gram-negative bacilli which are completely aerobic, non-motile, non-fermenting and yellow-pigmented with a characteristic fruity odor. species are widely...
The genus are gram-negative bacilli which are completely aerobic, non-motile, non-fermenting and yellow-pigmented with a characteristic fruity odor. species are widely found in the environment, especially in water and soil, and are considered as low-grade opportunistic pathogens for humans. infections are most commonly seen in immunocompromised patients and only rarely occur in immunocompetent patients. We here report the first confirmed catheter-related bloodstream infection (CRBSI) due to in an immunocompetent patient. We also review the literature related to infections.
PubMed: 32021328
DOI: 10.2147/IDR.S234778 -
Current Microbiology Mar 2020Massive blood loss, a common pathological complication in the clinic, is often accompanied by altered gut integrity and intestinal wall damage. Little is known to what...
Massive blood loss, a common pathological complication in the clinic, is often accompanied by altered gut integrity and intestinal wall damage. Little is known to what extent the gut microbiome could be correlated with this process. The gut microbiome plays a crucial role in human health, especially in immune and inflammatory responses. This study aims to determine whether acute blood loss affects the gut microbiome and the dynamic variation of the gut microbiome following the loss of blood. We used New Zealand rabbits to mimic the blood loss complication and designed a five-time-point fecal sampling strategy including 24-h pre-blood loss procedure, 24 h, 36 h, 48 h, and 1-week post-blood loss procedure. Gut microbiome composition and diversity were analyzed using 16S rRNA gene sequencing and downstream α-diversity, β-diversity, and taxonomy analysis. The gut microbiome changed dramatically after blood loss procedure. There was a significant increase in diversity and richness of the gut microbiome at 24-h post-procedure (P = 0.038). Based on an analysis of similarities, the composition of gut microbiome in the samples collected at 24-h post-procedure was significantly different from that of pre-procedure samples (r = 0.79, P = 0.004 weighted unifrac distance; r = 0.99, P = 0.002, unweighted unifrac distance). The relative abundance of Lactobacillus was significantly decreased in the post-procedure samples (P = 0.0006), while the relative abundance of Clostridiales (P = 0.018) and Bacteroidales (P = 0.015) was significantly increased after procedure. We also found the relative abundance of Bacilli, Lactobacillus, Myroides, and Prevotella decreased gradually at different time points after blood loss. The relative abundance of the Clostridia, Alphaproteobacteria, and Sporosarcina increased at 24-h post-procedure and decreased thereafter. This preliminary study discovered potential connections between blood loss and dysbiosis of gut microbiome. The diversity and abundance of the gut microbiome was affected to various extents after acute blood loss and unable to be restored to the original microbiome profile even after one week. The increase in relative abundance of opportunistic pathogens after blood loss could be an important indication to reconsider immune and inflammatory responses after acute blood loss from the perspective of gut microbiome.
Topics: Animals; Bacteria; Dysbiosis; Feces; Gastrointestinal Microbiome; Hemorrhage; Male; Opportunistic Infections; RNA, Ribosomal, 16S; Rabbits
PubMed: 31894374
DOI: 10.1007/s00284-019-01825-2 -
Scientific Reports Dec 2019The black blow fly, Phormia regina (Meigen) (Diptera: Calliphoridae) is one of the most abundant carrion flies in North America. Calliphorids are important in...
The black blow fly, Phormia regina (Meigen) (Diptera: Calliphoridae) is one of the most abundant carrion flies in North America. Calliphorids are important in agriculture and animal production, veterinary sciences, forensics and medical entomology. While the role of flies in the epidemiology of human and animal diseases is an active area of research, little is known about the microorganisms associated with these insects. We examined the diversity of wild-caught black blow fly endogenous (internal body) and exogenous (external body) microbial communities using 16S rRNA gene sequencing. Overall, 27 phyla, 171 families and 533 genera were detected, and diversity was significantly higher (P < 0.05) on external body surfaces. At the genus level, Dysgonomonas, Ignatzschineria, Acinetobacter, Vagococcus, Myroides, and Wohlfahrtiimonas were predominant. Cloning and sequencing of nearly full-length fragments of the 16S rRNA gene showed that some of the species identified are known to be pathogenic to humans, animals, and plants. Myroides odoratimimus and Acinetobacter radioresistens are well-known, multi-drug resistant bacteria. These results provide a snapshot of the microbial communities harbored by adult black blow flies and call for more comprehensive studies to better characterize the role these flies may play in the transmission of pathogenic microorganisms.
Topics: Animals; Biodiversity; Diptera; Farms; High-Throughput Nucleotide Sequencing; Humans; Metabolome; Metabolomics; Microbiota; Phylogeny; RNA, Ribosomal, 16S
PubMed: 31889104
DOI: 10.1038/s41598-019-56733-z -
Chemosphere Apr 2020Climatic factors particularly increased atmospheric temperature (IAT) greatly alters plant microbe and heavy metal interactions and subsequently reduces plant growth and...
Climatic factors particularly increased atmospheric temperature (IAT) greatly alters plant microbe and heavy metal interactions and subsequently reduces plant growth and phytoremediation efficiency. The aim of the study was to assess the effects of inoculation of chromium reducing-thermotolerant plant growth promoting bacteria (CRT-PGPB) on plant growth, physiological responses and chromium (Cr) uptake by Sorghum bicolor under IAT condition. Three potential CRT-PGPB strains were isolated from Cr contaminated sites and identified as Bacillus cereus TCR17, Providencia rettgeri TCR21 and Myroides odoratimimus TCR22 through molecular characterization. These strains displayed the potential to reduce Cr to Cr, produce siderophores, indole-3-acetic acid and solubilize phosphate. Inoculation of S. bicolor with CRT-PGPB increased plant growth, antioxidant status (superoxide dismutase, catalase and ascorbate peroxidase) and decreased proline and malondialdehyde contents in plants under Cr, IAT and Cr + IAT stress indicate that PGPB helped plants to reduce stress induced oxidative damage. Irrespective of IAT stress, inoculation of CRT-PGPB decreased the accumulation of Cr in plants compared with un-inoculated control suggest that CRT-PGPB might have the potential to improve phytostabilization process in Cr contaminated soils. Furthermore, gene expression studies confirmed that inoculation of TCR21 down-regulated the expression of proline synthesis gene (p5cs1) and up-regulated the expression of antioxidant related genes (sod, apx1 and cat) and stress tolerance genes (sHsp). Our results showed that CRT-PGPB exhibiting potential to tolerate Cr, temperature, produce plant beneficial metabolites and reduce Cr to Cr, can be exploited as potential inoculants for improving plant growth and phytoremediation process in Cr contaminated soil under IAT condition.
Topics: Antioxidants; Bacteria; Biodegradation, Environmental; Chromium; Gene Expression Regulation, Plant; Heat-Shock Response; Indoleacetic Acids; Metals, Heavy; Plant Development; Soil Microbiology; Soil Pollutants; Sorghum; Thermotolerance
PubMed: 31812764
DOI: 10.1016/j.chemosphere.2019.125521 -
International Journal of Biological... Aug 2020Myroilysin is a novel bacterial member of M12A metalloproteases family with an uncommon "cysteine switch" activation mechanism and a unique "cap" structure. However,...
Myroilysin is a novel bacterial member of M12A metalloproteases family with an uncommon "cysteine switch" activation mechanism and a unique "cap" structure. However, activation of pro-myroilysin is elusive. Here, mature myroilysin was obtained for structure determination by treating pro-myroilysin with trypsin. The structure of mature myroilysin showed that the active-site zinc ion of the mature protein is coordinated by three histidine residues, a water molecule, and a tyrosine residue (Tyr208) in the conserved Met-turn motif (SIMHY). The "cap" structure moves away from the active-site to leave the active cleft open; the newly formed N-terminus is deeply buried in myroilysin, and Glu151 forms a salt bridge directly with the first amino acid residue (Gly38), whereas they are far from each other in the pro-myroilysin. The mutation of Tyr208 indicates that Tyr208 plays an important role in activity of myroilysin. The proteolytic activity and thermostability of mutant E151A decreased dramatically, implying that Glu151 is not only important for catalysis, but also crucial for structural stability in myroilysin. Structural comparison also reveals differences existed between myroilysin and astacin. Our biochemical and structural data provide new insights into the activation of myroilysin and functional involvement of crucial residues Tyr208 and Glu151.
Topics: Amino Acid Motifs; Bacterial Proteins; Crystallography, X-Ray; Enzyme Activation; Enzyme Stability; Metalloproteases
PubMed: 31785296
DOI: 10.1016/j.ijbiomac.2019.11.205