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  • 1
    In: Antibiotics, MDPI AG, Vol. 10, No. 3 ( 2021-02-24), p. 226-
    Abstract: (1) Background: Colistin is a last-resort antibiotic used in treating multidrug-resistant Gram-negative infections. The growing emergence of colistin resistance in Escherichia coli (E. coli) represents a serious health threat, particularly to intensive care unit (ICU) patients. (2) Methods: In this work, we investigated the emergence of colistin resistance in 140 nosocomial E. coli isolated from patients with pneumonia and admitted to the chest ICU over 36 months. Virulence and resistance-related genes and E. coli pathotypes in colistin-resistant and colistin-sensitive isolates were determined. (3) Results: Colistin resistance was observed in 21/140 (15%) of the nosocomial E. coli isolates. The MIC50 of the resistant strains was 4 mg/L, while MIC90 was 16 mg/L. Colistin-resistant isolates were also co-resistant to amoxicillin, amoxicillin/clavulanic, aztreonam, ciprofloxacin, and chloramphenicol. The mechanism of colistin resistance was represented by the presence of mcr-1 in all resistant strains. Respectively, 42.9% and 36.1% of colistin-resistant and colistin-sensitive groups were extended-spectrum β-lactamase (ESBL) producers, while 23.8% and 21% were metallo β-lactamase (MBL) producers. blaTEM-type was the most frequently detected ESBL gene, while blaIMP-type was the most common MBL in both groups. Importantly, most resistant strains showed a significantly high prevalence of astA (76.2%), aggR (76.2%), and pic (52.4%) virulence-related genes. Enteroaggregative E. coli (76%) was the most frequently detected genotype among the colistin-resistant strains. (4) Conclusion: The high colistin resistance rate observed in E. coli strains isolated from patients with nosocomial pneumonia in our university hospital is worrisome. These isolates carry different drug resistance and virulence-related genes. Our results indicate the need for careful monitoring of colistin resistance in our university hospital. Furthermore, infection control policies restricting the unnecessary use of extended-spectrum cephalosporins and carbapenems are necessary.
    Type of Medium: Online Resource
    ISSN: 2079-6382
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2681345-2
    SSG: 15,3
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  • 2
    In: Antibiotics, MDPI AG, Vol. 11, No. 11 ( 2022-11-15), p. 1631-
    Abstract: Malaria is a persistent illness with a great public health concern. To combat this fatal disease, developing effective antimalarial medications has become a necessity. In the present study, we described the actinomycetes associated with the Red Sea soft coral Nephthea sp. and isolated a strain that was sub-cultured in three different media (M1, ISP2, and OLIGO). Actinomycete isolate’s phylogenetic analysis of the 16S rRNA gene revealed that it belongs to the genus Rhodococcus. In vitro screening of the antimalarial activity for three extracts against Plasmodium falciparum was carried out. Non-targeted metabolomics for the chemical characterization of the isolated actinomycete species UA111 derived extracts were employed using high-resolution liquid chromatography–mass spectrometry (LC-HR-MS) for dereplication purposes. Additionally, statistical analysis of the vast LC-MS data was performed using MetaboAnalyst 5.0. Finally, an in silico analysis was conducted to investigate the potential chemical compounds that could be the source of the antimalarial potential. The results revealed that ISP2 media extract is the most effective against Plasmodium falciparum, according to antimalarial screening (IC50 8.5 µg/mL), in contrast, OLIGO media extract was inactive. LC-HRMS-based metabolomics identified a range of metabolites, mainly alkaloids, from the genus Rhodococcus. On the other hand, multivariate analysis showed chemical diversity between the analyzed samples, with ISP2 extract being optimal. The docking analysis was able to anticipate the various patterns of interaction of the annotated compounds with three malarial protein targets (P. falciparum kinase, P. falciparum cytochrome bc1 complex, and P. falciparum lysyl-tRNA synthetase). Among all of the test compounds, perlolyrine (11) and 3097-B2 (12) displayed the best docking profiles. In conclusion, this work demonstrated the value of the established method for the metabolic profiling of marine actinomycetes using the data from liquid chromatography–mass spectrometry (LC-MS), which helps to streamline the difficult isolation stages required for their chemical characterization. In addition, the antimalarial efficacy of this strain has intriguing implications for future pharmaceutical development.
    Type of Medium: Online Resource
    ISSN: 2079-6382
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2681345-2
    SSG: 15,3
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  • 3
    In: Current Pharmaceutical Analysis, Bentham Science Publishers Ltd., Vol. 16, No. 4 ( 2020-04-27), p. 404-411
    Abstract: A new simple and sensitive high-Performance Liquid Chromatography (HPLC) method for the determination of a potent synthetic cannabinoid THJ-2201, has been developed and validated. Lixiviptan was used as the Internal Standard (IS). Methods: THJ-2201 and IS were extracted from mouse plasma using deproteinization procedure that uses acetonitrile followed by HPLC analysis. The separation was carried out on a reversed-phase C18 column using water and acetonitrile mixture (30:70 v/v). The flow-rate was 1.0 mL/min. Eluting of both THJ-2201 and lixivaptan was performed at 220 nm. Results: The method demonstrated linearity over a calibration range of 95 - 1500 ng/mL and the Limit of Detection (LOD) and Quantitation (LOQ) were 28 ng/mL and 91 ng/mL, respectively. The validation of the proposed method was carried out by following the US Food and Drug Administration (FDA) guidelines. Intra- and inter-day precision did not exceed 6.4%, whereas the accuracy of THJ-2201 measurements was within ±13%. Conclusion: This new method is simple and sensitive and has been applied successfully in a pharmacokinetic study of THJ-2201 in mouse plasma. The mean values of Tmax and Cmax were 0.25 h and 141.87 ± 12.11 ng/mL, respectively.
    Type of Medium: Online Resource
    ISSN: 1573-4129
    Language: English
    Publisher: Bentham Science Publishers Ltd.
    Publication Date: 2020
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  • 4
    In: Chirality, Wiley, Vol. 26, No. 3 ( 2014-03), p. 132-135
    Abstract: The present work aimed to investigate the predictability of the chromatographic behavior for the separation of underivatized amino acids on ristocetin A, known as Chirobiotic R, using a DryLab high‐performance liquid chromatography (HPLC) method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. After implementing the basic runs, and judging the predictability via the computed resolution map, it can be deduced that the chiral recognition mechanisms tend towards a hydrophilic interaction chromatography rather than the reversed phase mode, which limits the ability of DryLab software to predict separations on Chirobiotic R. Chirality 26:132–135, 2014 . © 2014 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 0899-0042 , 1520-636X
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2014
    detail.hit.zdb_id: 2001237-8
    SSG: 12
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  • 5
    In: Chirality, Wiley, Vol. 25, No. 9 ( 2013-09), p. 506-513
    Abstract: Pharmaceutical companies worldwide tend to apply chiral chromatographic separation techniques in their mass production strategy rather than asymmetric synthesis. The present work aims to investigate the predictability of chromatographic behavior of enantiomers using DryLab HPLC method development software, which is typically used to predict the effect of changing various chromatographic parameters on resolution in the reversed phase mode. Three different types of chiral stationary phases were tested for predictability: macrocyclic antibiotics‐based columns (Chirobiotic V and T), polysaccharide‐based chiral column (Chiralpak AD‐RH), and protein‐based chiral column (Ultron ES‐OVM). Preliminary basic runs were implemented, then exported to DryLab after peak tracking was accomplished. Prediction of the effect of % organic mobile phase on separation was possible for separations on Chirobiotic V for several probes: racemic propranolol with 97.80% accuracy; mixture of racemates of propranolol and terbutaline sulphate, as well as, racemates of propranolol and salbutamol sulphate with average 90.46% accuracy for the effect of percent organic mobile phase and average 98.39% for the effect of pH; and racemic warfarin with 93.45% accuracy for the effect of percent organic mobile phase and average 99.64% for the effect of pH. It can be concluded that Chirobiotic V reversed phase retention mechanism follows the solvophobic theory. Chirality 25:506–513, 2013 . © 2013 Wiley Periodicals, Inc.
    Type of Medium: Online Resource
    ISSN: 0899-0042 , 1520-636X
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2013
    detail.hit.zdb_id: 2001237-8
    SSG: 12
    SSG: 15,3
    Location Call Number Limitation Availability
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