ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
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2018
·
IF 3.974
Xiaoxin Chen,Sheng He,Xiaolu Liu,Jiye Hu
Using sequential soil and liquid culture enrichments with cyprodinil as the sole carbon source, a Gram-negative cyprodinil-degrader from cyprodinil-polluted agricultural soil was isolated. The sequencing analysis of 16 S rRNA indicated that the strain showed 99% homology to Acinetobacter sp. The strain could effectively degrade cyprodinil at the neutral condition. At the initial concentrations of 10, 20, 50, 100, 150 and 200 mg L −1 in minimal medium, cyprodinil was degraded by 10, 20, 49.3, 64.2, 57 and 24 mg L −1 within 14 days, respectively. Two metabolites (4-cyclopropyl-6-methyl-2-pyrimidpyridine amine and monohydroxylated para-substitution) were identified using high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS/MS). A biodegradation pathway involving imines hydrolysis and monohydroxyl substitution on benzene ring was proposed on basis of the identified metabolites. Acinetobacter sp. would have a potential application in bioremediation of cyprodinil-contaminated soil, and the strain might have important implications in detoxification and bioremediation of pyrimidine analogues.
研究领域:
环境微生物学
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生物修复
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农药降解
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土壤科学
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DOI
PubMed
高影响因子
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
·
2018
·Vol. 62
·期 2
·
IF 4.256
Cheng Wang,Gaomei Zhao,Song Wang,Yin Chen,Yali Gong,Shilei Chen,Yang Xu,Mengjia Hu,Xinmiao Wang,Hao Zeng,Aiping Wang,Dengqun Liu,Yongping Su,Tianmin Cheng,Fang Chen,Junping Wang
The increasing incidence of multidrug-resistant Acinetobacter baumannii (MDRAb) infections worldwide has necessitated the development of novel antibiotics. Human defensin 5 (HD5) is an endogenous peptide with a complex architecture and antibacterial activity against MDRAb. In the present study, we attempted to simplify the structure of HD5 by removing disulfide bonds. We found that the Cys2-4 bond was most indispensable for HD5 to inactivate MDRAb, although the antibacterial activity of the derivative was significantly attenuated. We then replaced the noncationic and nonhydrophobic residues with electropositive Arg to increase the antibacterial activity of HD5 derivative that contains a Cys2-4 bond, obtaining another derivative termed HD5d5. The in vitro antibacterial assay and irradiation-wound-infection animal experiment both showed that HD5d5 was much more effective than HD5 at eliminating MDRAb. Further investigations revealed that HD5d5 efficiently bound to outer membrane lipid A and penetrated membranes, leading to bacterial collapse and peptide translocation. Compared to HD5, more HD5d5 molecules were located in the cytoplasm of MDRAb, and HD5d5 was more efficient at reducing the activities of superoxide dismutase and catalase, causing the accumulation of reactive oxygen species that are detrimental to microbes. In addition, HD5 failed to suppress the pathogenic outer membrane protein A of Acinetobacter baumannii (AbOmpA) at concentrations up to 50 μg/ml, whereas HD5d5 strongly bound to AbOmpA and exhibited a dramatic toxin-neutralizing ability, thus expanding the repertoire of drugs that is available to treat MDRAb infections.
研究领域:
微生物学
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药理学
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传染病学
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PubMed
高影响因子
Experimental and Therapeutic Medicine
·
2019
·Vol. 18
·期 4
·2924-2932
·
IF 1.448
Jingjing Wang,Yongzhong Ning,Shu Li,Yun Wang,Jinhua Liang,Chunming Jin,Hairun Yan,Yongcun Huang
Acinetobacter baumannii is an important cause of hospital‑acquired, multidrug‑resistant (MDR) infections occurring worldwide. Anti‑microbial combination regimens may be the only feasible treatment option for affected patients. In the present study, the efficacy of the combined therapy of meropenem with colistin, ampicillin‑sulbactam, tazobactam and vancomycin against clinical strains of MDR A. baumannii was determined. Anti‑microbial susceptibility testing was performed and resistance genes were characterized by a multiplex polymerase chain reaction (PCR)‑reverse line blot assay. The genetic background of New Delhi metallo‑β‑lactamase 1 (NDM‑1) was analysed by primer walking. The presence of NDM‑1 was detected using the modified Hodge test and the EDTA‑combined disk test. To screen for synergistic drug effects, the fractional inhibitory concentration index was calculated using a checkerboard assay. The results of the PCR as well as the sequence analyses suggested that NDM‑1 was located downstream of the ISAba125 element. In addition, a synergistic effect was determined for meropenem + vancomycin, meropenem + tazobactam and meropenem + ampicillin + sulbactam in two strains each, and in four strains for meropenem + colistin. A total of five A. baumannii strains with resistance to numerous antibiotics and carrying numerous resistance genes were identified. In the strains of A. baumannii, the NDM‑1 gene was integrated in a transposon structure with a copy of the ISAba125 insertion sequence. However, the genetic background was not identical among the different species and strains. The genetic variability of NDM‑1 may facilitate the rapid dissemination of this gene. In conclusion, meropenem may enhance the efficacy of antibiotics in A. baumannii strains with NDM‑1‑associated MDR.
研究领域:
微生物学
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传染病学
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临床医学
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DOI
PubMed
高影响因子
Current Research in Microbial Sciences
·
2024
·
IF 4.8
Sirui Zhang,Jingdan Wang,Rong Yu,Haiping Liu,Shuyan Liu,Kai Luo,Jin'e Lei,Bei Han,Yanjiong Chen,Shaoshan Han,E Yang,Meng Xun,Lei Han
Although various mechanisms of carbapenem-resistance have been identified in the nosocomial pathogen Acinetobacter baumannii , the critical process of resistance evolution and the factors involved in are not well understood. Herein, we identified a universal stress protein Usp1413 which played an important role in adaptive resistance of A. baumannii to meropenem (MEM). Based on RNA-Seq and genome sequencing, Usp1413 was not only one of the most downregulated USPs, but also the bare one having mutation of tyrosine and glycine inserted at the site of 229-230 (YG229-230) under the stimulation of MEM. Deletion of Usp1413 resulted in increased MEM resistance. In addition, Usp1413 affected the bacterial abilities of biofilm formation and swarm motility, as well as helped A. baumannii response to various environmental stresses. These effects of Usp1413 were achieved by regulating its interaction proteins, within the functions of YigZ family protein, acetyltransferase, and SulP family inorganic anion transporter. The insertion mutation of YG229-230 influenced both the expression of interaction proteins and the phenotypes of bacteria. Finally, the promotor region of Usp1413 was convinced by point mutations. Overall, our findings identified the universal stress protein Usp1413 as a contributor involved in MEM adaptive resistance and responded to numerous environmental stresses. This study provides novel insights into the mechanism of universal stress proteins in participating antibiotic resistance, and affords a potential target for controlling drug resistance development in A. baumannii .
研究领域:
微生物学
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抗药性研究
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分子生物学
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DOI
PubMed
高影响因子
Frontiers in Cellular and Infection Microbiology
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2024
·
IF 4.6
Li Pu,Zhang Sirui,Wang Jingdan,Al-Shamiri Mona Mohamed,Luo Kai,Liu Shuyan,Mi Peng,Wu Xiaokang,Liu Haiping,Tian Huohuan,Han Bei,Lei Jin’e,Han Shaoshan,Han Lei
Introduction: The type VI secretion system (T6SS) is a crucial virulence factor in the nosocomial pathogen Acinetobacter baumannii. However, its association with drug resistance is less well known. Notably, the roles that different T6SS components play in the process of antimicrobial resistance, as well as in virulence, have not been systematically revealed.Methods: The importance of three representative T6SS core genes involved in the drug resistance and virulence of A. baumannii, namely, tssB, tssD (hcp), and tssM was elucidated.Results: A higher ratio of the three core genes was detected in drug-resistant strains than in susceptible strains among our 114 A. baumannii clinical isolates. Upon deletion of tssB in AB795639, increased antimicrobial resistance to cefuroxime and ceftriaxone was observed, alongside reduced resistance to gentamicin. The ΔtssD mutant showed decreased resistance to ciprofloxacin, norfloxacin, ofloxacin, tetracycline, and doxycycline, but increased resistance to tobramycin and streptomycin. The tssM-lacking mutant showed an increased sensitivity to ofloxacin, polymyxin B, and furazolidone. In addition, a significant reduction in biofilm formation was observed only with the ΔtssM mutant. Moreover, the ΔtssM strain, followed by the ΔtssD mutant, showed decreased survival in human serum, with attenuated competition with Escherichia coli and impaired lethality in Galleria mellonella.Discussion: The above results suggest that T6SS plays an important role, participating in the antibiotic resistance of A. baumannii, especially in terms of intrinsic resistance. Meanwhile, tssM and tssD contribute to bacterial virulence to a greater degree, with tssM being associated with greater importance.
研究领域:
微生物学
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传染病学
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抗菌素耐药性
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分子生物学
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PubMed
高影响因子
Microbial Cell Factories
·
2024
·Vol. 23
·期 1
·1-14
·
IF 4.3
Song Yuping,Lv Hongfa,Xu Lei,Liu Zhiying,Wang Jianfeng,Fang Tianqi,Deng Xuming,Zhou Yonglin,Li Dan
Background Inorganic polyphosphate (polyP)-targeted polyphosphate kinase 1 (PPK1) has attracted much attention by virtue of its importance in bacterial pathogenicity and persistence, as well as its exclusive presence in microorganisms. However, only very few drugs have been found to be efficacious in inhibiting the Acinetobacter baumannii (A. baumannii) PPK1 protein.Results In this study, we identified Scutellarein (Scu), a potent PPK1 inhibitor that could significantly influence PPK1-regulated motility, biofilm formation, and bacterial persistence, which was further validated by the results of transcriptome analysis. Mechanistic explorations revealed that Scu achieved its enzyme inhibitory activity predominantly through direct engagement with the active center of PPK1. Moreover, the survival rate of Galleria mellonella larvae was increased by about 35% with 20 mg/kg of Scu treatment. The remarkable therapeutic benefits of Scu were also observed in the mouse pneumonia model, shown mainly by reduced bacterial colonization, pathological lesions, and inflammatory factors.Conclusion Our results revealed that Scu could attenuate the pathogenicity and persistence of A. baumannii by interfering with its important kinase PPK1.
研究领域:
微生物学
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药理学
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感染病学
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PubMed
高影响因子
VETERINARY MICROBIOLOGY
·
2023
·
IF 3.3
Yumeng Cheng,Yakun Li,Meng Yang,Yang He,Xinru Shi,Zhidan Zhang,Yesheng Zhong,Yuan Zhang,Hongbin Si
Antibiotic-resistant bacteria are emerging all the time, but the continued emergence of novel resistance genes and genetic structures is even more alarming. Tigecycline is currently the important last barrier in the treatment of multidrug-resistant (MDR) infections. tet (X), a resistance gene to tigecycline, is the most prevalent and constantly emerging novel variants. In this research, we characterized two MDR Acinetobacter indicus strains to tigecycline that were identified and analyzed by antimicrobial susceptibility testing, conjugation transfer, whole genome sequencing (WGS) and bioinformatics analysis, and gene function analysis. The results showed that three tet (X) variants were carried in BDT201, including tet (X6) on the chromosome, tet (X3) on the plasmid pBDT201–2, and a novel tet (X5) variant adjacent to the IS Aba1 elements on the plasmid pBDT201–3. The novel Tet(X5) variant showed 98.7% amino acid identity with Tet(X5) and was named Tet(X5.4). By expressing tet (X5.4) gene, the tigecycline minimum inhibitory concentration (MIC) values for Escherichia coli JM109 increased 32- fold (from 0.13 to 4 mg/L). BDT2076 contained tigecycline and carbapenems resistance genes, such as tet (X3), bla OXA-58 , bla NDM-3 , and bla CARB-2 . The continuous emergence of MDR bacteria and resistance genes is a global environmental health issue that can not be ignored and therefore needs to pay more urgent attention to it.
研究领域:
微生物学
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分子生物学
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抗生素研究
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环境健康
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DOI
高影响因子
Microorganisms
·
2022
·Vol. 10
·期 4
·722
·
IF 4.926
Mariateresa Ceparano,Valentina Baccolini,Giuseppe Migliara,Claudia Isonne,Erika Renzi,Daniela Tufi,Corrado De Vito,Maria De Giusti,Maria Trancassini,Francesco Alessandri,Giancarlo Ceccarelli,Francesco Pugliese,Paolo Villari,Maria Angiulli,Stefania Battellito,Arianna Bellini,Andrea Bongiovanni,Lucilla Caivano,Marta Castellani,Monica Coletti,Alessia Cottarelli,Ludovica D’Agostino,Andrea De Giorgi,Chiara De Marchi,Irma Germani,Dara Giannini,Elisa Mazzeo,Shadi Orlandi,Matteo Piattoli,Eleonora Ricci,Leonardo Maria Siena,Alessandro Territo,Gianluca Vrenna,Stefano Zanni,Carolina Marzuillo
Infections caused byAcinetobacter baumanniirepresent a major concern for intensive care unit (ICU) patients. However, the epidemiology of these infections among COVID-19 patients has not been fully explored. The aims of this study were (i) to characterize the clonal spread ofA. baumanniiamong COVID-19 patients admitted to the ICU of the Umberto I hospital of Rome during the first year of the pandemic and (ii) to identify risk factors for its acquisition. Isolates were analysed by pulsed-field gel electrophoresis, and a multivariable regression model was constructed. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. Overall, 193 patients were included, and 102 strains were analysed. All isolates had highly antibiotic-resistant profiles and derived from two genotypes. The cumulative incidence ofA. baumanniiacquisition (colonization or infection) was 36.8%. Patients withA. baumanniihad higher mortality and length of stay. Multivariable analysis showed that previous carbapenem use was the only risk factor associated withA. baumanniiacquisition (aOR: 4.15, 95% CI: 1.78–9.64). We documented substantialA. baumanniiinfections and colonization and high levels of clonal transmission. Given the limited treatment options, effective prevention and containment strategies to limit the spread ofA. baumanniishould be implemented.
研究领域:
微生物学
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流行病学
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感染病学
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DOI
高影响因子
MICROCHEMICAL JOURNAL
·
2026
·
IF 5.2
Xiaoyue Chen,Yushu Zhang,Ruiying Zhou,Xing Liu,Yuyu Tan,Xiling Xiao
Acinetobacter baumannii ( A. baumannii ), a prevalent multidrug-resistant nosocomial pathogen, necessitates rapid and highly sensitive detection, which is crucial for clinical diagnosis and infection control. This study endeavors to develop a dual-amplification electrochemical sensor utilizing catalytic hairpin assembly (CHA) and nanoporous gold (NPG) to facilitate ultra-sensitive detection of A. baumannii . Initially, an NPG electrode characterized by a three-dimensional porous architecture and high specific surface area was fabricated through the dealloying method, enabling the first-stage substrate amplification. Subsequently, a CHA cyclic amplification system was introduced, the target gene sequence triggers cascade hybridization reactions between two hairpin probes (H1−H2), cyclically producing a substantial number of H1-H2 double-stranded complexes, thus achieving the second stage of signal amplification. Moreover, the recognition and amplification processes are integrated within a single system, offering the advantages of being enzyme-free and user-friendly. A limit of detection (LOD) as low as 70 CFU/mL was achieved with a good linear range (10(Scoffone et al., 2025a 2 –10(Wong et al., 2017 7 ). In samples of spiked artificial cerebrospinal fluid (CSF), recovery rates varied from 94.6% to 103.0%, underscoring its potential applicability in complex matrices. This study successfully developed a highly efficient dual-amplification sensing platform and offers a novel and reliable analytical approach for the rapid, on-site detection of A. baumannii .
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高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Zhe Dou,Guochao Xu,Ye Ni
A novel carboxylesterase Ac Est1 was identified from Acinetobacter sp. JNU9335 with high efficiency in the biosynthesis of chiral precursor of Edoxaban through kinetic resolution of methyl 3-cyclohexene-1-carboxylate (CHCM). Sequence analysis revealed Ac Est1 belongs to family IV of esterolytic enzymes and exhibits <40% identities with known carboxylesterases. The optimum pH and temperature of recombinant Ac Est1 are 8.0 and 40 °C. Substrate spectrum analysis indicated that Ac Est1 prefers substrates with short acyl and alcohol groups. Ac Est1 was highly active in the hydrolysis of CHCM with k cat of 1153 s −1 and displayed high substrate tolerance. As much as 2.0 M (280 g·L −1 ) CHCM could be enantioselectively hydrolyzed into ( S )-CHCM by merely 0.08 g·L −1 Ac Est1 with ee s of >99% ( S ) and substrate to catalyst ratio (S/C) of 3500 g·g −1 . These results indicate that the novel Ac Est1 is a promising biocatalyst in the synthesis of chiral carboxylic acids.
研究领域:
生物催化
·
酶学
·
药物化学
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PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2026
·
IF 5.2
Chengjie Jiang,Yanlin Wang,Xinxing Chen,Shaoning Yu,Jianhua Zhu,Heng Fan
Aptamer-assisted MOF-on-MOF heterostructure for dual-mode AB sensing. • Orthogonal fluorescence/colorimetric self-validation in ICU matrices. • Boronic-acid/aptamer dual recognition for bacterial capture. • Ultrasensitive Acinetobacter baumannii detection with 5–12 CFU/mL LOD. • Accurate analysis of ICU swabs, hand wash, and ventilator condensate. Acinetobacter baumannii (AB) has become the most persistent “resident pathogen” in intensive care unit (ICU) environments due to its exceptional environmental survival capability, its ability to persist on dry inanimate surfaces, highly efficient adhesion through biofilm formation that resists disinfectants, and extensive multidrug resistance. Rapid and reliable monitoring of AB is essential for preventing healthcare-associated infections in ICUs. However, existing microbiological and molecular methods remain limited by slow turnaround times, high costs, and inadequate sensitivity for routine environmental screening. Here, we report a label-free, dual-mode fluorescence–colorimetric biosensing platform that integrates aptamer-mediated magnetic capture with a MOF-on-MOF heterostructure probe for ultrasensitive detection of AB in environmental samples from ICUs. The probe, ZrFe-MOF@Eu-MOF-BA, was constructed through the epitaxial growth of boronic acid-functionalized Eu-MOF shells on ZrFe-MOF. This heterostructure combines ligand-centered fluorescence, Fe 3+ /Fe 2+ -driven peroxidase-mimicking catalytic activity, and high-density boronic acid groups, enabling covalent affinity toward cis-diol-rich glycolipids on the AB surface. A robust magnetic sandwich complex is formed with aptamer-modified magnetic beads, allowing independent quantification through two orthogonal readouts. Across a broad range of 10–10 8 CFU/mL, the system achieved limits of detection of 5 and 8 CFU/mL in colorimetric mode (370 and 652 nm) and 12 CFU/mL in fluorescence mode. The sensor displayed good selectivity against the tested interfering bacteria and maintained high accuracy in spiked ICU environmental matrices, including hand-wash solutions, surface swabs, and ventilator condensates. Recoveries ranged from 92.3% to 108.0%, with RSDs < 4.5%. Strong agreement between the two detection channels further enhanced the reliability of the results. This work demonstrates a highly sensitive, low-cost, and easily deployable dual-mode biosensor suitable for rapid screening of AB contamination in clinical environments. The modular aptamer-based recognition mechanism also enables straightforward adaptation of the platform for the detection of other pathogenic microorganisms, offering broad potential for clinical surveillance and environmental biosensing applications Download: Download high-res image (86KB) Download: Download full-size image
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高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2025
·
IF 3.7
Jing Wu,Zhenggang Han,Pengrong Li,Jing Li,Yuanyuan Chen,Shangbo Ning,Hong-jun Chao,Xue-wang Gao,Dazhong Yan
Cyclohexylamine oxidase is a member of amine oxidases that catalyzes the conversion of cyclohexylamine to cyclohexanone. In our previous work, the enzymatic activity assay of cyclohexylamine oxidase CHAO YT-02 indicated that its specific activity towards cyclohexylamine of CHAO YT-02 was ten times higher than that of its homolog CHAO IH-35A . In this study, the crystal structure of CHAO YT-02 was determined by the molecular replacement method at a resolution of 1.49 Å. The atomic structure revealed that the amino acid residues Leu302, Trp70, Phe197, Phe349, and Tyr440 constitute the active center pocket of the enzyme. Amino acid residues Ile180, Leu181, and Trp332 separate the active center pocket and an intermediate pocket. Moreover, a molecular dynamics (MD) simulation and the calculation of the binding free energy were performed to predict substrate entry and product release from cyclohexylamine oxidases. Single-amino acid substitution mutants (W70A, I180A, L181A, I208A, F197A, L302A, W332A, F349A, and Y440A) of CHAO YT-02 were constructed to investigate the role of these amino acid residues in enzymatic properties and substrate specificity. The results indicated that both the amino acid residues in the active center pocket and gating the two pockets affected the activity or substrate specificity of CHAO YT-02 . This study on the structure and catalytic mechanism of cyclohexylamine oxidase is beneficial to eliminating toxic amine compounds in the environment.
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高影响因子
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