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Frontiers in Microbiology 2022has recently gained increased importance owing to the New Delhi metallo-β-lactamase (NDM) and other β-lactamases produced by its clinical isolates. These enzymes...
has recently gained increased importance owing to the New Delhi metallo-β-lactamase (NDM) and other β-lactamases produced by its clinical isolates. These enzymes reduce the efficiency of antimicrobial therapy. Herein, we reported the findings of whole-genome sequence analysis and a comprehensive pan-genome analysis performed on a multidrug-resistant . 18004577 clinical strain recovered from the urine of a hospitalized patient in Shandong, China, in 2018. 18004577 was found to have a genome assembly size of 4.6 Mb with a G + C content of 41%; a circular plasmid p18004577_NDM of 273.3 Kb, harboring an accessory multidrug-resistant region; and a circular, stable IncT plasmid p18004577_Rts of 146.2 Kb. Additionally, various resistance genes were identified in its genome, including , , , (), (), (), , , , (), and . Conjugation experiments and whole-genome sequencing revealed that the gene could be transferred to the transconjugant the formation of pJ18004577_NDM, a novel hybrid plasmid. Based on the genetic comparison, the main possible formation process for pJ18004577_ was the insertion of the []() translocatable unit module from p18004577_ into plasmid p18004577_Rts in the Russian doll insertion structure (), which played a role similar to that of using the "copy-in" route in the mobilization of [()] . The array, multiplicity, and diversity of the resistance and virulence genes in this strain necessitate stringent infection control, antibiotic stewardship, and periodic resistance surveillance/monitoring policies to preempt further horizontal and vertical spread of the resistance genes. Roary analysis based on 30 . pan genome identified 415 core, 756 soft core, 5,744 shell, and 12,967 cloud genes, highlighting the "close" nature of . pan-genome. After a comprehensive pan-genome analysis, representative biological information was revealed that included phylogenetic distances, presence or absence of genes across the . bacteria clade, and functional distribution of proteins. Moreover, pan-genome analysis has been shown to be an effective approach to better understand . bacteria because it helps develop various tailored therapeutic strategies based on their biological similarities and differences.
PubMed: 36687647
DOI: 10.3389/fmicb.2022.1071385 -
Journal of Atrial Fibrillation 2013This manuscript aims to review the current knowledge in the field of surgical ablation of atrial fibrillation (AF), including a brief discussion regarding the standard... (Review)
Review
This manuscript aims to review the current knowledge in the field of surgical ablation of atrial fibrillation (AF), including a brief discussion regarding the standard Maze procedure, its variants, minimally invasive thoracoscopic procedures and hybrid treatments, which briefly summarizes the advantages and differences between each technique. The rationale for the surgical approach of the left atrial appendage, its different techniques and complications will also be briefly covered. To conclude, the current Expert Consensus recommendations will be reviewed and an algorithm for the surgical management of the patient with AF, suggesting which technique applies better to which patient, under specific settings, will also be proposed.
PubMed: 28496848
DOI: 10.4022/jafib.743 -
Frontiers in Cellular and Infection... 2021is a nosocomial pathogen associated with urinary tract infections related to hospital-acquired Infections. In recent years, clinical strains producing New Delhi...
is a nosocomial pathogen associated with urinary tract infections related to hospital-acquired Infections. In recent years, clinical strains producing New Delhi Metallo-β-lactamase (NDM) and other β-lactamase which reduce the efficiency of antimicrobial therapy have been reported. However, there are few reports of co-producing two metallo-β-lactamases in one isolate. Here, we first reported a strain (P138) co-harboring , , and . The specie were identified using MALDI-TOF MS. The results of antimicrobial susceptibility testing by broth microdilution method indicated that P138 was resistant to meropenem (MIC = 64μg/ml), imipenem (MIC = 64μg/ml), and aztreonam (MIC = 32μg/ml). Conjugation experiments revealed that the -carrying plasmid was transferrable. The carbapenemase genes were detected using PCR and confirmed by PCR-based sequencing. The complete genomic sequence of the was identified using Illumina (Illumina, San Diego, CA, USA) short-read sequencing (150bp paired-end reads), and many common resistance genes had been identified, including , , , , , , and . The gene was characterized by the following structure: IS-TnpA-IntI1-aadB-IS-GroEL-GroES-DsbD-PAI-ble--IS-QnrS1-IS. Blast comparison revealed that the gene structure shared >99% similarity with plasmid p5_SCLZS62 (99% nucleotide identity and query coverage). In summary, we isolated a strain coproducing , , and blaOXA-10. To the best of our acknowledge, this was first reported in the world. The occurrence of the strain needs to be closely monitored.
Topics: Anti-Bacterial Agents; China; Enterobacteriaceae Infections; Humans; Microbial Sensitivity Tests; Providencia; beta-Lactamases
PubMed: 35047418
DOI: 10.3389/fcimb.2021.789646 -
Journal of Bacteriology Aug 2020Chlorogenic acid (CGA) is a phenolic compound with well-known antibacterial properties against pathogens. In this study, structural and biochemical characterization was...
Chlorogenic acid (CGA) is a phenolic compound with well-known antibacterial properties against pathogens. In this study, structural and biochemical characterization was used to show the inhibitory role of CGA against the enzyme of the shikimate pathway, a well-characterized drug target in several pathogens. Here, we report the crystal structures of dehydroquinate synthase (DHQS), the second enzyme of the shikimate pathway, from (DHQS), in binary complex with NAD and ternary complex with NAD and CGA. Structural analyses reveal that CGA occupies the substrate position in the active site of DHQS, which disables domain movements, leaving the enzyme in an open and catalysis-incompetent state. The binding analyses by isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) show that CGA binds to DHQS with (equilibrium dissociation constant) values of 6.3 μM and 0.5 μM, respectively. nzyme inhibition studies show that CGA inhibits DHQS with a of 235 ± 21 μM, while it inhibits the growth of , , , and with MIC values of 60 to 100 μM. In the presence of aromatic amino acids supplied externally, CGA does not show the toxic effect. These results, along with the observations of the inhibition of the 3-deoxy-d-arabino-heptulosonate-7-phosphate (DAHP) regulatory domain by CGA in our previous study, suggest that CGA binds to shikimate pathway enzymes with high affinity and inhibits their catalysis and can be further exploited for designing novel drug-like molecules. The shikimate pathway is an attractive target for the development of herbicides and antimicrobial agents, as it is essential in plants, bacteria, and apicomplexan parasites but absent in humans. The enzymes of shikimate pathway are conserved among bacteria. Thus, the inhibitors of the shikimate pathway act on wide range of pathogens. We have identified that chlorogenic acid targets the enzymes of the shikimate pathway. The crystal structure of dehydroquinate synthase, the second enzyme of the pathway, in complex with chlorogenic acid and enzymatic inhibition studies explains the mechanism of inhibition of chlorogenic acid. These results suggest that chlorogenic acid has a good chemical scaffold and have important implications for its further development as a potent inhibitor of shikimate pathway enzymes.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Binding Sites; Catalytic Domain; Chlorogenic Acid; Kinetics; Phosphorus-Oxygen Lyases; Protein Binding; Providencia; Shikimic Acid
PubMed: 32661075
DOI: 10.1128/JB.00248-20 -
Proceedings. Biological Sciences Jan 2018Understanding the rate of evolutionary change and the genetic architecture that facilitates rapid adaptation is a current challenge in evolutionary biology. Comparative...
Understanding the rate of evolutionary change and the genetic architecture that facilitates rapid adaptation is a current challenge in evolutionary biology. Comparative studies show that genes with immune function are among the most rapidly evolving genes across a range of taxa. Here, we use immune defence in natural populations of to understand the rate of evolution in natural populations and the genetics underlying rapid change. We probed the immune system using the natural pathogens and to measure post-infection survival and bacterial load of wild populations collected across seasonal time along a latitudinal transect along eastern North America (Massachusetts, Pennsylvania and Virginia). There are pronounced and repeatable changes in the immune response over the approximately 10 generations between spring and autumn collections, with a significant but less distinct difference observed among geographical locations. Genes with known immune function are not enriched among alleles that cycle with seasonal time, but the immune function of a subset of seasonally cycling alleles in immune genes was tested using reconstructed outbred populations. We find that flies containing seasonal alleles in () have different functional responses to infection and that epistatic interactions among seasonal and () alleles underlie the immune phenotypes observed in natural populations. This rapid, cyclic response to seasonal environmental pressure broadens our understanding of the complex ecological and genetic interactions determining the evolution of immune defence in natural populations.
Topics: Adaptation, Physiological; Animals; Drosophila Proteins; Drosophila melanogaster; Enterococcus faecalis; Evolution, Molecular; Female; Immunity, Innate; Male; Massachusetts; Pennsylvania; Providencia; Seasons; Virginia
PubMed: 29321302
DOI: 10.1098/rspb.2017.2599 -
Antimicrobial Agents and Chemotherapy Apr 2001The sequences of the bla(TEM) genes encoding TEM-92 in Proteus mirabilis and Providencia stuartii isolates were determined and were found to be identical. Except for...
The sequences of the bla(TEM) genes encoding TEM-92 in Proteus mirabilis and Providencia stuartii isolates were determined and were found to be identical. Except for positions 218 (Lys-6) and 512 (Lys-104), the nucleotide sequence of bla(TEM-92) was identical to that of bla(TEM-20), including the sequence of the promoter region harboring a 135-bp deletion combined with a G-162-->T substitution. The deduced amino acid sequence of TEM-92 differed from that of TEM-52 by the presence of a substitution (Gln-6-->Lys) in the peptide signal.
Topics: Amino Acid Substitution; Enterobacteriaceae Infections; Genes, Bacterial; Humans; Microbial Sensitivity Tests; Promoter Regions, Genetic; Proteus Infections; Proteus mirabilis; Providencia; Sequence Analysis, DNA; beta-Lactam Resistance; beta-Lactamases
PubMed: 11257046
DOI: 10.1128/AAC.45.4.1278-1280.2001 -
Frontiers in Microbiology 2021Multidrug-resistant bacteria from different sources have been steadily emerging, and an increasing number of resistance mechanisms are being uncovered. In this work, we...
Multidrug-resistant bacteria from different sources have been steadily emerging, and an increasing number of resistance mechanisms are being uncovered. In this work, we characterized a novel resistance gene named from an isolate of a novel species, R33 (CCTCC AB 2021339). Susceptibility testing and enzyme kinetic parameter analysis were conducted to determine the function of the aminoglycoside 2'--acetyltransferase. Whole-genome sequencing and comparative genomic analysis were performed to elucidate the molecular characteristics of the genome and the genetic context of the resistance gene-related sequences. Among the functionally characterized resistance genes, AAC(2')-If shares the highest amino acid sequence identity of 70.79% with AAC(2')-Ia. AAC(2')-If confers resistance to several aminoglycoside antibiotics, showing the highest resistance activity against ribostamycin and neomycin. The recombinant strain harboring (pUCP20-/DH5α) showed 256- and 128-fold increases in the minimum inhibitory concentration (MIC) levels to ribostamycin and neomycin, respectively, compared with those of the control strains (DH5α and pUCP20/DH5α). The results of the kinetic analysis of AAC(2')-If were consistent with the MIC results of the cloned with the highest catalytic efficiency for ribostamycin ( ratio = [3.72 ± 0.52] × 10 M s). Whole-genome sequencing demonstrated that the gene was located on the chromosome with a relatively unique genetic environment. Identification of a novel aminoglycoside resistance gene in a strain of a novel species will help us find ways to elucidate the complexity of resistance mechanisms in the microbial population.
PubMed: 34867838
DOI: 10.3389/fmicb.2021.711037 -
Infection and Immunity Mar 2023Prior exposure to a pathogen can greatly influence the outcome of a secondary infection, and although invertebrates lack classically defined adaptive immunity, their...
Prior exposure to a pathogen can greatly influence the outcome of a secondary infection, and although invertebrates lack classically defined adaptive immunity, their immune response is still influenced by prior immune challenges. While the strength and specificity of such immune priming depends highly on the host organism and infecting microbe, chronic bacterial infection of the fruit fly Drosophila melanogaster with species isolated from wild-caught fruit flies provides broad nonspecific protection against a later secondary bacterial infection. To determine how chronic infection influences progression of secondary infection, we specifically tested how chronic infection with Serratia marcescens and Enterococcus faecalis impacted both resistance and tolerance to a secondary infection with an unrelated bacterium, Providencia rettgeri, by simultaneously tracking survival and bacterial load postinfection across a range of infectious doses. We found that these chronic infections increased both tolerance and resistance to . Further investigation of S. marcescens chronic infection also revealed robust protection against the highly virulent Providencia sneebia, and that protection was dependent on the initial infectious dose for S. marcescens with protective doses corresponding with significantly increased diptericin expression. While the increased expression of this antimicrobial peptide gene likely explains the increased resistance, increased tolerance is likely due to other alterations in organismal physiology, such as increased negative regulation of immunity or tolerance of ER stress. These findings provide a foundation for future studies on how chronic infection influences tolerance to secondary infection.
Topics: Animals; Drosophila melanogaster; Persistent Infection; Coinfection; Bacteria; Bacterial Infections
PubMed: 36794959
DOI: 10.1128/iai.00360-22 -
Journal of Global Antimicrobial... Mar 2020A molecular analysis was performed of two Providencia rettgeri (P. rettgeri) strains (Pr 297 and Pr 269) collected in 2007 and 2009 from wound swabs of patients admitted...
OBJECTIVES
A molecular analysis was performed of two Providencia rettgeri (P. rettgeri) strains (Pr 297 and Pr 269) collected in 2007 and 2009 from wound swabs of patients admitted to the intensive care units at Joseph Ravoangy Andrianavalona hospital and the Military Hospital in Antananarivo, Madagascar.
METHODS
The two P. rettgeri isolates were subjected to susceptibility testing. Whole genome sequencing was performed to characterise the antibiotic resistance genes, genomic islands and mobilomes (integrons, plasmids and insertion sequences).
RESULTS
All isolates were found to be multidrug-resistant. Antibiotic-resistant genes described were amongst eight different classes of antimicrobial agents. Thirty insertion sequences and twelve genomic islands were predicted in each genome. Class 1 and class 2 integrons were found in both genomes, with gene cassette regions encompassing arr-2 - cmlA5 - bla - ant (3")-Ia and dfrA1 - sat2 - ant (3")-Ia - orfX, respectively. IncA/C2, ColM and ColE1-like plasmids were described harbouring bla, qnrD and aac(6')-Ib-cr4 genes, respectively. Phylogenetic analysis showed that Pr 297 and Pr 269 isolates were genetically identical and clustered with P. rettgeri strains described in the USA and Spain.
CONCLUSIONS
It is believed that this is the first molecular characterisation of wound infection pathogens from Madagascan patients and the first description of P. rettgeri co-producing CMY-30, OXA-10 and AAC(6')-Ib-cr4 enzymes. The diversity of the resistance determinants and mobile genetic elements was probably due to extensive horizontal gene transfer events, highlighting the need to conduct further molecular monitoring studies to understand the genomic plasticity of resistant bacteria in Madagascan hospitals.
Topics: Anti-Bacterial Agents; Drug Resistance, Multiple, Bacterial; Gene Transfer, Horizontal; Genome, Bacterial; Genomic Islands; High-Throughput Nucleotide Sequencing; Humans; Interspersed Repetitive Sequences; Madagascar; Microbial Sensitivity Tests; Phylogeny; Plasmids; Providencia; Spain; United States; Whole Genome Sequencing; Wound Infection
PubMed: 31325615
DOI: 10.1016/j.jgar.2019.07.013 -
MSphere Jun 2024
PubMed: 38742900
DOI: 10.1128/msphere.00288-24