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The American Journal of Tropical... Nov 2023Kocuria species are normal commensals of the skin that have been found in various environmental niches and are usually considered nonpathogenic. However, according to...
Kocuria species are normal commensals of the skin that have been found in various environmental niches and are usually considered nonpathogenic. However, according to recent literature, Kocuria spp. have been associated with human infections. Kocuria palustris is an emerging opportunistic pathogen with great potential to cause disease in immunocompromised patients. The isolation and identification of this pathogen is necessary, as timely treatment with the appropriate antibiotics can help in reducing mortality among these patients. We present three cases of bacteremia in immunocompromised patients admitted to our hospital; one patient was receiving chemotherapy for gall bladder carcinoma, the second was on maintenance hemodialysis for chronic kidney disease, and the third was receiving chemotherapy for acute myeloid leukemia. All three patients presented with a fever in the setting of neutropenia during the course of treatment with chemotherapy (in Cases 1 and 3) or hemodialysis (in Case 2). The blood culture samples of all the patients had pure isolates of Kocuria species K. palustris, which was identified by matrix assisted laser desorption ionisation- time of flight mass spectrometry (MALDI-ToF MS). All three patients presented with febrile neutropenia during the course of treatment with chemotherapy (in Cases 1 and 3) or hemodialysis (in Case 2).
Topics: Humans; Bacteremia; Micrococcaceae; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Immunocompromised Host
PubMed: 37722665
DOI: 10.4269/ajtmh.23-0377 -
Bioscience, Biotechnology, and... Apr 2024Human lysozyme (hLYZ) has attracted considerable research attention due to its natural and efficient antibacterial abilities and widespread uses. In this study, hLYZ was...
Human lysozyme (hLYZ) has attracted considerable research attention due to its natural and efficient antibacterial abilities and widespread uses. In this study, hLYZ was modified to enhance its enzyme activity and expressed in a Pichia pastoris expression system. A combination mutant HZM(2R-K)-N88D/V110S demonstrated the highest enzyme activity (6213 ± 164 U/mL) in shake flasks, which was 4.07-fold higher when compared with the original strain. Moreover, the recombinant P. pastoris was inducted in a 3 L bioreactor plus methanol/sorbitol co-feeding. After 120 h induction, the antibacterial activity of hLYZ reached 2.23 ± 0.12 × 105 U/mL, with the specific activity increasing to 1.89 × 105 U/mg, which is currently the highest specific activity obtained through recombinant expression of hLYZ. Also, hLYZ supernatants showed 2-fold inhibitory effects toward Staphylococcus aureus and Micrococcus lysodeikticus when compared with HZM(2R-K). Our research generated a hLYZ mutant with high antibacterial capabilities and provided a method for screening of high-quality enzymes.
Topics: Muramidase; Anti-Bacterial Agents; Humans; Recombinant Proteins; Staphylococcus aureus; Bioreactors; Micrococcus; Gene Expression; Mutation; Saccharomycetales; Microbial Sensitivity Tests
PubMed: 38409797
DOI: 10.1093/bbb/zbae023 -
Journal of Hazardous Materials Feb 2024The increasing discharge of antibiotic residues into the natural environment, stemming from both human activities and animal farming, has detrimental effects on natural...
The increasing discharge of antibiotic residues into the natural environment, stemming from both human activities and animal farming, has detrimental effects on natural ecosystems and serves as a significant driving force for the spread of antibiotic resistance. Biodegradation is an important method for the elimination of antibiotics from contaminated substrates, but the identifying in situ microbial populations involved in antibiotic degradation is challenging. Here, DNA stable isotope probing (DNA-SIP) was employed to identify active sulfadiazine (SDZ) degrading microbes in the gut of black soldier fly larvae (BSFLs). At an initial SDZ concentration of 100 mg kg, the highest degradation efficiency reached 73.99% after 6 days at 28 °C. DNA-SIP revealed the incorporation of C from labeled SDZ in 9 genera, namely, Clostridum sensu stricto 1, Nesterenkonia, Bacillus, Halomonas, Dysgonomonas, Caldalkalibacillus, Enterococcus, g_unclassified_f_Xanthomonadaceae and g_unclassified_f_Micrococcaceae. Co-occurrence network analysis revealed that a significant positive correlation existed among SDZ degrading microbes in the gut microbiota, e.g., between Clostridium sensu stricto 1 and Nesterenkonia. Significant increases in carbohydrate metabolism, membrane transport and translation were crucial in the biodegradation of SDZ in the BSFL gut. These results elucidate the structure of SDZ-degrading microbial communities in the BSFL gut and in situ degradation mechanisms.
Topics: Animals; Humans; Sulfadiazine; Anti-Bacterial Agents; Diptera; Microbiota; Larva; DNA
PubMed: 37922583
DOI: 10.1016/j.jhazmat.2023.132892 -
Applied and Environmental Microbiology Feb 2024Engineering the plant microbiome with beneficial endophytic bacteria can improve the growth, health, and productivity of the holobiont. Here, we administered two...
Engineering the plant microbiome with beneficial endophytic bacteria can improve the growth, health, and productivity of the holobiont. Here, we administered two beneficial bacterial strains, VR04 sp. and GR12 sp., to micropropagated grapevine cuttings obtained via somatic embryogenesis. While both strains colonized the plant endosphere, only GR12 sp. increased root biomass under nutritional-deficit conditions, as supported by the plant growth promotion traits detected in its genome. Phylogenetic and co-occurrence analyses revealed that the plant native bacterial community, originally dominated by Streptococcaceae and Micrococcaceae, dramatically changed depending on the inoculation treatments, as invading strains differently affected the relative abundance and the interactions of pre-existing taxa. After 30 days of plantlets' growth, became a predominant taxon, and considering untreated plantlets as references, sp. GR12 showed a minor impact on the endophytic bacterial community. On the other hand, sp. VR04 caused a major change in community composition, suggesting an opportunistic colonization pattern. Overall, the results corroborate the importance of preserving the native endophytic community structure and functions during plant microbiome engineering.IMPORTANCEA better comprehension of bacterial colonization processes and outcomes could benefit the use of plant probiotics in the field. In this study, we applied two different beneficial bacteria to grapevine micropropagated plantlets and described how the inoculation of these strains impacts endophytic microbiota assembly. We showed that under nutritional deficit conditions, the response of the receiving endophytic bacterial communities to the invasion of the beneficial strains related to the manifestation of plant growth promotion effects by the inoculated invading strains. sp. GR12 was able to preserve the native microbiome structure despite its effective colonization, highlighting the importance of the plant-endophyte associations for the holobiont performance. Moreover, our approach showed that the use of micropropagated plantlets could be a valuable strategy to study the interplay among the plant, its native microbiota, and the invader on a wider portfolio of species besides model plants, facilitating the application of new knowledge in agriculture.
Topics: Agricultural Inoculants; Phylogeny; Plant Roots; Bacteria; Enterobacteriaceae; Endophytes
PubMed: 38289136
DOI: 10.1128/aem.02078-23 -
Microbiology Spectrum Dec 2023As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat...
As the management of wheat fungal diseases becomes increasingly challenging, the use of bacterial agents with biocontrol potential against the two major wheat phytopathogens, and , may prove to be an interesting alternative to conventional pest management. Here, we have shown that dimethylpolysulfide volatiles are ubiquitously and predominantly produced by wheat-associated and actinomycetes, displaying antifungal activity against both pathogens. By limiting pathogen growth and DON virulence factor production, the use of such DMPS-producing strains as soil biocontrol inoculants could limit the supply of pathogen inocula in soil and plant residues, providing an attractive alternative to dimethyldisulfide fumigant, which has many non-targeted toxicities. Notably, this study demonstrates the importance of bacterial volatile organic compound uptake by inhibited , providing new insights for the study of volatiles-mediated toxicity mechanisms within bacteria-fungus signaling crosstalk.
Topics: Arthrobacter; Microbacterium; Triticum; Actinobacteria; Actinomyces; Soil; Plant Diseases
PubMed: 37800942
DOI: 10.1128/spectrum.05292-22 -
The Science of the Total Environment Mar 2024Microplastics derived from polyethylene (PE) mulch films are widely found in farmland soils and present considerable potential threats to agricultural soil ecosystems....
Microplastics derived from polyethylene (PE) mulch films are widely found in farmland soils and present considerable potential threats to agricultural soil ecosystems. However, the influence of microplastics derived from PE mulch films, especially those derived from farmland residual PE mulch films, on soil ecosystems remains unclear. In this study, we analyzed the bacterial communities attached to farmland residual transparent PE mulch film (FRMF) collected from peanut fields and the different ecological effects of unused PE mulch film-derived microplastics (MPs) and FRMF-derived microplastics (MPs-aged) on the soil and earthworm Metaphire guillelmi gut microbiota, functional traits, and co-occurrence patterns. The results showed that the assembly and functional patterns of the bacterial communities attached to the FRMF were clearly distinct from those in the surrounding farmland soil, and the FRMF enriched some potential plastic-degrading and pathogenic bacteria, such as Nocardioidaceae, Clostridiaceae, Micrococcaceae, and Mycobacteriaceae. MPs substantially influenced the assembly and functional traits of soil bacterial communities; however, they only significantly changed the functional traits of earthworm gut bacterial communities. MPs-aged considerably affected the assembly and functional traits of both soil and earthworm gut bacterial communities. Notably, MPs had a more remarkable effect on nitrogen-related functions than the MPs-aged in numbers for both soil and earthworm gut samples. Co-occurrence network analysis revealed that both MPs and MPs-aged enhanced the synergistic interactions among operational taxonomic units (OTUs) of the composition networks for all samples. For community functional networks, MPs and MPs-aged enhanced the antagonistic interactions for soil samples; however, they exhibited contrasting effects for earthworm gut samples, as MPs enhanced the synergistic interactions among the functional contents. These findings broaden and deepen our understanding of the effects of FRMF-derived microplastics on soil ecosystems, suggesting that the harmful effects of aged plastics on the ecological environment should be considered.
Topics: Animals; Soil; Farms; Oligochaeta; Gastrointestinal Microbiome; Microplastics; Plastics; Ecosystem; Polyethylene
PubMed: 38224880
DOI: 10.1016/j.scitotenv.2024.170094 -
Animals : An Open Access Journal From... May 2024The vaginal tract comprises commensal microorganisms, which play an essential role in the health of the reproductive tract. Any dysbiosis in the vaginal microenvironment...
The vaginal tract comprises commensal microorganisms, which play an essential role in the health of the reproductive tract. Any dysbiosis in the vaginal microenvironment may lead to severe urinary tract infections or even infertility. This study aimed to evaluate the aerobic bacterial flora isolated from vaginal samples from 100 lactating bitches in the antepartum period ( = 3), postpartum period ( = 80), and with ( = 17). Before vaginal swabs, all the bitches went through a gynecology consult, along with milk and blood sampling. Standard microbiological techniques were used for bacterial isolation. Among the 100 vaginal samples analyzed, 82% had a positive microbiological outcome, while 18% were negative. The microbiologic profile listed 17 different genera. The main isolated bacterial families were Micrococcaceae, Staphylococcaceae, Morganellaceae, Bacillaceae, and Rhizobiaceae. At the same time, strains like , , , , , or were isolated for the first time from the vaginal secretion of lactating bitches. The microbiological data demonstrates that lactating bitches' vaginal discharge is heterogeneous and may be affected by coitus, sampling season, age, and reproductive status.
PubMed: 38791718
DOI: 10.3390/ani14101501 -
Fish & Shellfish Immunology Jun 2024Copper/zinc superoxide dismutase (Cu/Zn-SOD) can effectively eliminate reactive oxygen species (ROS),avoid damage from O to the body, and maintain O balance. In this...
Copper/zinc superoxide dismutase (Cu/Zn-SOD) can effectively eliminate reactive oxygen species (ROS),avoid damage from O to the body, and maintain O balance. In this study, multi-step high-performance liquid chromatography (HPLC), combined with Mass Spectrometry (MS), was used to isolate and identify Cu/Zn-SOD from the serum of Pinctada fucata martensii (P. f. martensii) and was designated as PmECSOD. With a length of 1864 bp and an open reading frame (ORF) of 1422 bp, the cDNA encodes a 473 amino acid protein. The PmECSOD transcript was detected in multiple tissues by quantitative real-time PCR (qRT-PCR), with its highest expression level being in the gills. Additionally, the temporal expression of PmECSOD mRNA in the hemolymph was highest at 48 h after in vivo stimulation with Escherichia coli and Micrococcus luteus. The results from this study provide a valuable base for further exploration of molluscan innate immunity and immune response.
Topics: Animals; Pinctada; Superoxide Dismutase; Amino Acid Sequence; Immunity, Innate; Phylogeny; Gene Expression Profiling; Base Sequence; Sequence Alignment; Escherichia coli; DNA, Complementary; Micrococcus luteus; Gene Expression Regulation; RNA, Messenger
PubMed: 38701990
DOI: 10.1016/j.fsi.2024.109599 -
BMC Genomics Sep 2023Paenarthrobacter nicotinovorans ATCC 49919 uses the pyridine-pathway to degrade nicotine and could provide a renewable source of precursors from nicotine-containing...
BACKGROUND
Paenarthrobacter nicotinovorans ATCC 49919 uses the pyridine-pathway to degrade nicotine and could provide a renewable source of precursors from nicotine-containing waste as well as a model for studying the molecular evolution of catabolic pathways and their spread by horizontal gene transfer via soil bacterial plasmids.
RESULTS
In the present study, the strain was sequenced using the Illumina NovaSeq 6000 and Oxford Nanopore Technology (ONT) MinION platforms. Following hybrid assembly with Unicycler, the complete genome sequence of the strain was obtained and used as reference for whole-genome-based phylogeny analyses. A total of 64 related genomes were analysed; five Arthrobacter strains showed both digital DNA-DNA hybridization and average nucleotide identity values over the species threshold when compared to P. nicotinovorans ATCC 49919. Five plasmids and two contigs belonging to Arthrobacter and Paenarthrobacter strains were shown to be virtually identical with the pAO1 plasmid of Paenarthrobacter nicotinovorans ATCC 49919. Moreover, a highly syntenic nic-genes cluster was identified on five plasmids, one contig and three chromosomes. The nic-genes cluster contains two major locally collinear blocks that appear to form a putative catabolic transposon. Although the origins of the nic-genes cluster and the putative transposon still elude us, we hypothesise here that the ATCC 49919 strain most probably evolved from Paenarthrobacter sp. YJN-D or a very closely related strain by acquiring the pAO1 megaplasmid and the nicotine degradation pathway.
CONCLUSIONS
The data presented here offers another snapshot into the evolution of plasmids harboured by Arthrobacter and Paenarthrobacter species and their role in the spread of metabolic traits by horizontal gene transfer among related soil bacteria.
Topics: Nicotine; Micrococcaceae; Soil; DNA
PubMed: 37697273
DOI: 10.1186/s12864-023-09644-3 -
Enfermedades Infecciosas Y... Apr 2024The development and research of new technologies for identifying microorganisms, has allowed the identification of hitherto unknown bacteria. Auritidibacter ignavus is a... (Review)
Review
INTRODUCTION
The development and research of new technologies for identifying microorganisms, has allowed the identification of hitherto unknown bacteria. Auritidibacter ignavus is a newly described Gram-positive rod possibly associated with otitis, although its role as an etiologic agent in otitis is currently controversial.
METHODS
We report two cases of recurrent otitis in paediatric patients in which A. ignavus was isolated and review the previous cases reported in the literature.
RESULTS
All the isolates were identified as A. ignavus by proteomic and genomic methods. Both patients recovered from their symptoms.
CONCLUSION
A. ignavus was recovered from ear discharges of paedriatic patients with chronic ear problems. All the cases previously reported in the literature were adults. More evidence is needed for the association between A. ignavus and otitis, since data regarding this species are still scarce.
Topics: Adult; Humans; Child; Patient Discharge; Proteomics; Micrococcaceae; Otitis
PubMed: 38262875
DOI: 10.1016/j.eimce.2024.01.009