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Turner JM, Stratton CM, Bala S, Cardenas Alvarez M, Nicholas RA, Davies C. Ureidopenicillins Are Potent Inhibitors of Penicillin-Binding Protein 2 from Multidrug-Resistant Neisseria gonorrhoeae H041. ACS Infect Dis 2024; 10:1298-1311. [PMID: 38446051 DOI: 10.1021/acsinfecdis.3c00713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Effective treatment of gonorrhea is threatened by the increasing prevalence of Neisseria gonorrhoeae strains resistant to the extended-spectrum cephalosporins (ESCs). Recently, we demonstrated the promise of the third-generation cephalosporin cefoperazone as an antigonococcal agent due to its rapid second-order rate of acylation against penicillin-binding protein 2 (PBP2) from the ESC-resistant strain H041 and robust antimicrobial activity against H041. Noting the presence of a ureido moiety in cefoperazone, we evaluated a subset of structurally similar ureido β-lactams, including piperacillin, azlocillin, and mezlocillin, for activity against PBP2 from H041 using biochemical and structural analyses. We found that the ureidopenicillin piperacillin has a second-order rate of acylation against PBP2 that is 12-fold higher than cefoperazone and 85-fold higher than ceftriaxone and a lower MIC against H041 than ceftriaxone. Surprisingly, the affinity of ureidopenicillins for PBP2 is minimal, indicating that their inhibitory potency is due to a higher rate of the acylation step of the reaction compared to cephalosporins. Enhanced acylation results from the combination of a penam scaffold with a 2,3-dioxopiperazine-containing R1 group. Crystal structures show that the ureido β-lactams overcome the effects of resistance mutations present in PBP2 from H041 by eliciting conformational changes that are hindered when PBP2 interacts with the weaker inhibitor ceftriaxone. Overall, our results support the potential of piperacillin as a treatment for gonorrhea and provide a framework for the future design of β-lactams with improved activity against ESC-resistant N. gonorrhoeae.
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Affiliation(s)
- Jonathan M Turner
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, United States
| | - Caleb M Stratton
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688, United States
| | - Sandeepchowdary Bala
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688, United States
| | - Maria Cardenas Alvarez
- Departments of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Robert A Nicholas
- Departments of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Christopher Davies
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama 36688, United States
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2
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Djorić D, Atkinson SN, Kristich CJ. Reciprocal regulation of enterococcal cephalosporin resistance by products of the autoregulated yvcJ-glmR-yvcL operon enhances fitness during cephalosporin exposure. PLoS Genet 2024; 20:e1011215. [PMID: 38512984 PMCID: PMC10986989 DOI: 10.1371/journal.pgen.1011215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 04/02/2024] [Accepted: 03/06/2024] [Indexed: 03/23/2024] Open
Abstract
Enterococci are commensal members of the gastrointestinal tract and also major nosocomial pathogens. They possess both intrinsic and acquired resistance to many antibiotics, including intrinsic resistance to cephalosporins that target bacterial cell wall synthesis. These antimicrobial resistance traits make enterococcal infections challenging to treat. Moreover, prior therapy with antibiotics, including broad-spectrum cephalosporins, promotes enterococcal proliferation in the gut, resulting in dissemination to other sites of the body and subsequent infection. As a result, a better understanding of mechanisms of cephalosporin resistance is needed to enable development of new therapies to treat or prevent enterococcal infections. We previously reported that flow of metabolites through the peptidoglycan biosynthesis pathway is one determinant of enterococcal cephalosporin resistance. One factor that has been implicated in regulating flow of metabolites into cell wall biosynthesis pathways of other Gram-positive bacteria is GlmR. In enterococci, GlmR is encoded as the middle gene of a predicted 3-gene operon along with YvcJ and YvcL, whose functions are poorly understood. Here we use genetics and biochemistry to investigate the function of the enterococcal yvcJ-glmR-yvcL gene cluster. Our results reveal that YvcL is a DNA-binding protein that regulates expression of the yvcJ-glmR-yvcL operon in response to cell wall stress. YvcJ and GlmR bind UDP-GlcNAc and reciprocally regulate cephalosporin resistance in E. faecalis, and binding of UDP-GlcNAc by YvcJ appears essential for its activity. Reciprocal regulation by YvcJ/GlmR is essential for fitness during exposure to cephalosporin stress. Additionally, our results indicate that enterococcal GlmR likely acts by a different mechanism than the previously studied GlmR of Bacillus subtilis, suggesting that the YvcJ/GlmR regulatory module has evolved unique targets in different species of bacteria.
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Affiliation(s)
- Dušanka Djorić
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Samantha N. Atkinson
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
- Center for Microbiome Research, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Christopher J. Kristich
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
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3
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Hu JJ, Ma N, Wu NP, Wang JP. Production of AmpC β-Lactamase and Development of a Competitive Array for Discriminative Determination of Cephalosporins in Milk. J Agric Food Chem 2023; 71:19111-19120. [PMID: 38011504 DOI: 10.1021/acs.jafc.3c06792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
In this study, AmpC β-lactamase of Escherichia coli was expressed, and its intermolecular interaction mechanisms with 15 cephalosporins (CPs) were studied by using a molecular docking technique. Results showed that this enzyme mainly interacted with the β-lactam ring of these CPs, and the key contacting amino acids were Ser80 and Ser228. The AmpC β-lactamase was combined with 5 horseradish peroxidase-labeled conjugates to develop a direct competitive array on a microplate for determination of 15 drugs in milk. Due to the use of principal component analysis method to analyze the data, this method could discriminate the 15 drugs at the concentration as low as 10 ng/mL. The detection results for the unknown milk samples were consistent with those obtained by the liquid chromatography-mass spectrometry method. As a general comparison, this method is better than the previous antibody-based and receptor-based detection methods for CPs. This is the first paper reporting a competitive array for discriminative determination of a class of small-molecule substances.
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Affiliation(s)
- Jia Jia Hu
- College of Veterinary Medicine, Hebei Agricultural University, Baoding, Hebei 071000, China
| | - Ning Ma
- College of Veterinary Medicine, Hebei Agricultural University, Baoding, Hebei 071000, China
| | - Ning Peng Wu
- Henan Institute of Veterinary Drug and Feed Control, Zhengzhou, Henan 450002, China
| | - Jian Ping Wang
- College of Veterinary Medicine, Hebei Agricultural University, Baoding, Hebei 071000, China
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4
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Panda AP, Pandey SD, Jain D, Ghosh AS. The MSMEG_1586 of M. smegmatis Is a Penicillin-Interactive Enzyme That Can Potentially Hydrolyse Aztreonam and Cephalosporins. Curr Microbiol 2023; 81:26. [PMID: 38041782 DOI: 10.1007/s00284-023-03545-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 10/30/2023] [Indexed: 12/03/2023]
Abstract
Mycobacteria are intrinsically resistant to beta-lactams as they possess several putative penicillin-interactive enzymes (PIEs), some of those are with dual-activity, namely DD-carboxypeptidase and beta-lactamase. Here, with help of molecular approaches, we elucidated the nature of one such putative PIE, MSMEG_1586, in Mycobacterium smegmatis. The in vivo expression of the membrane-bound form of MSMEG_1586 enhanced the beta-lactam resistance of a beta-lactamase deleted host E. coli strain (AM1OC), particularly for aztreonam (eight-fold) and cephalosporins (8-16 fold). To understand the reason for such elevation of resistance, soluble-form of MSMEG_1586 (sMSMEG_1586) was created by removing signal peptides and partially eliminating the amphipathic helix, and finally, expressed and purified. The purified sMSMEG_1586 was active and manifested a strong penicillin-binding affinity as shown by its ability to bind to fluorescent penicillin (Bocillin-FL). Interestingly, the steady-state kinetics apparently confirmed the hydrolytic ability of sMSMEG_1586 towards cefotaxime and aztreonam where hydrolysing aztreonam is a unique and rare behaviour among the beta-lactamases. However, sMSMEG_1586 was devoid of exerting DD-carboxypeptidase like activity. Finally, in silico analysis of MSMEG_1586 revealed a special folding that resembles class C beta-lactamase, except for the absence of a characteristic R2 loop. Overall, MSMEG_1586 could be categorized as a cephalosporinase with the ability to hydrolyse aztreonam.
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Affiliation(s)
- Aditya Prasad Panda
- Department of Biosciences and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
| | - Satya Deo Pandey
- Department of Biosciences and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, 40202, USA
| | - Diamond Jain
- Department of Biosciences and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India
| | - Anindya S Ghosh
- Department of Biosciences and Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India.
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5
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Darrah K, Albright S, Kumbhare R, Tsang M, Chen JK, Deiters A. Antisense Oligonucleotide Activation via Enzymatic Antibiotic Resistance Mechanism. ACS Chem Biol 2023; 18:2176-2182. [PMID: 37326511 PMCID: PMC10592181 DOI: 10.1021/acschembio.3c00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023]
Abstract
The structure and mechanism of the bacterial enzyme β-lactamase have been well-studied due to its clinical role in antibiotic resistance. β-Lactamase is known to hydrolyze the β-lactam ring of the cephalosporin scaffold, allowing a spontaneous self-immolation to occur. Previously, cephalosporin-based sensors have been developed to evaluate β-lactamase expression in both mammalian cells and zebrafish embryos. Here, we present a circular caged morpholino oligonucleotide (cMO) activated by β-lactamase-mediated cleavage of a cephalosporin motif capable of silencing the expression of T-box transcription factor Ta (tbxta), also referred to as no tail a (ntla), eliciting a distinct, observable phenotype. We explore the use of β-lactamase to elicit a biological response in aquatic embryos for the first time and expand the utility of cephalosporin as a cleavable linker beyond targeting antibiotic-resistant bacteria. The addition of β-lactamase to the current suite of enzymatic triggers presents unique opportunities for robust, orthogonal control over endogenous gene expression in a spatially resolved manner.
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Affiliation(s)
- Kristie
E. Darrah
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Savannah Albright
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Rohan Kumbhare
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Michael Tsang
- Department
of Developmental Biology, University of
Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - James K. Chen
- Department
of Chemical and Systems Biology, Stanford
University School of Medicine, Stanford, California 94305, United States
| | - Alexander Deiters
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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6
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Lu S, Montoya M, Hu L, Neetu N, Sankaran B, Prasad BVV, Palzkill T. Mutagenesis and structural analysis reveal the CTX-M β-lactamase active site is optimized for cephalosporin catalysis and drug resistance. J Biol Chem 2023; 299:104630. [PMID: 36963495 PMCID: PMC10139949 DOI: 10.1016/j.jbc.2023.104630] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 03/17/2023] [Accepted: 03/19/2023] [Indexed: 03/26/2023] Open
Abstract
CTX-M β-lactamases are a widespread source of resistance to β-lactam antibiotics in Gram-negative bacteria. These enzymes readily hydrolyze penicillins and cephalosporins, including oxyimino-cephalosporins such as cefotaxime. To investigate the preference of CTX-M enzymes for cephalosporins, we examined eleven active-site residues in the CTX-M-14 β-lactamase model system by alanine mutagenesis to assess the contribution of the residues to catalysis and specificity for the hydrolysis of the penicillin, ampicillin, and the cephalosporins cephalothin and cefotaxime. Key active site residues for class A β-lactamases, including Lys73, Ser130, Asn132, Lys234, Thr216, and Thr235, contribute significantly to substrate binding and catalysis of penicillin and cephalosporin substrates in that alanine substitutions decrease both kcat and kcat/KM. A second group of residues, including Asn104, Tyr105, Asn106, Thr215, and Thr216, contribute only to substrate binding, with the substitutions decreasing only kcat/KM. Importantly, calculating the average effect of a substitution across the 11 active-site residues shows that the most significant impact is on cefotaxime hydrolysis while ampicillin hydrolysis is least affected, suggesting the active site is highly optimized for cefotaxime catalysis. Furthermore, we determined X-ray crystal structures for the apo-enzymes of the mutants N106A, S130A, N132A, N170A, T215A, and T235A. Surprisingly, in the structures of some mutants, particularly N106A and T235A, the changes in structure propagate from the site of substitution to other regions of the active site, suggesting that the impact of substitutions is due to more widespread changes in structure and illustrating the interconnected nature of the active site.
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Affiliation(s)
- Shuo Lu
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Miranda Montoya
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Liya Hu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Neetu Neetu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Banumathi Sankaran
- Department of Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - B V Venkataram Prasad
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Timothy Palzkill
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.
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7
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Muhsin EA, Sajid Al-Jubori S, Abdulhemid Said L. Prevalence of Efflux Pump and Porin-Related Antimicrobial Resistance in Clinical Klebsiella pneumoniae in Baghdad, Iraq. Arch Razi Inst 2022; 77:785-798. [PMID: 36284955 PMCID: PMC9548288 DOI: 10.22092/ari.2022.356976.1952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/16/2022] [Indexed: 05/24/2023]
Abstract
Klebsiella pneumoniae is an opportunistic bacterium that causes many infections, including septicemia, pneumonia, urinary tract infection, and liver abscesses. There are many mechanisms for antibiotic resistance and K. pneumonia is considered a multidrug-resistant pathogen. This study aimed to find the correlation between the susceptibility of K. pneumonia to certain antibiotics with the porin-related resistance and pumps mechanisms. In total, two genes that are responsible for porin formation were considered in the current study OmpK-35gene and OmpK-36 gene, in addition to other four genes (CfiaS, CfiaL, MFS, and MdtK genes) related to an efflux pump mechanism of antibiotic resistance. The bacterial resistance was investigated towards five cephalosporins (Cefazolin, Cefoxitin, Ceftazidime, Ceftriaxone, and Cefepime) and two carbapenems (imipenem and ertapenem). Clinical samples, including blood, swabs, and urine, consisting of 20 specimens for each group, were collected from patients who attended three hospitals in Baghdad. The VITEK-2 system and genetic tests (polymerase chain reaction and sequencing) of bacterial isolates were applied to confirm the diagnosis of K. pneumoniae and detect the antibiotic sensitivity profile. The results showed that 51 (85%) and 15 (25%) of the total 60 isolates had positive results for OmpK-35 and Omp-K36 genes, respectively. The MFS and MdtK genes were observed (70-88.3%) in cephalosporin-resistant isolates of K. pneumoniae. There were no significant variations of bacterial resistance genes of antibiotics within the specimen groups. It was concluded that the bacterial resistance of the selected antibiotics was elevated markedly with the loss of the OmpK-36 gene with a high expression of MFS and MdtK genes and a slight minimal occurrence in the new generation of carbapenems. The best antimicrobial agent was ertapenem with a percentage of 0% of resistance in all bacterial isolates.
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Affiliation(s)
| | - S Sajid Al-Jubori
- Biology Department, College of Science, Mustansiriyah University, Baghdad, Iraq
| | - L Abdulhemid Said
- Biology Department, College of Science, Mustansiriyah University, Baghdad, Iraq
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Lazzaro LM, Cassisi M, Stefani S, Campanile F. Impact of PBP4 Alterations on β-Lactam Resistance and Ceftobiprole Non-Susceptibility Among Enterococcus faecalis Clinical Isolates. Front Cell Infect Microbiol 2022; 11:816657. [PMID: 35127564 PMCID: PMC8811369 DOI: 10.3389/fcimb.2021.816657] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/23/2021] [Indexed: 12/18/2022] Open
Abstract
Penicillin-resistance among Enterococcus faecalis clinical isolates has been recently associated with overexpression or aminoacidic substitutions in low-affinity PBP4. Ceftobiprole (BPR), a new-generation cephalosporin, is a therapeutic option against E. faecalis. Here, we present evidence that pbp4 gene sequence alterations may influence the expression level of the gene and ceftobiprole binding to PBP4 in E. faecalis clinical isolates showing remarkable MDR-phenotypes, and how this could interfere with BPR in vitro antibacterial and bactericidal activity. Seven E. faecalis strains from bloodstream infections were analyzed for their antibiotic and β-lactam resistance. BPR bactericidal activity was assessed by time-kill analysis; pbp4 genes were sequenced and pbp4 relative expression levels of transcription were performed by RT-qPCR. Five penicillin-resistant ampicillin-susceptible (PRAS) isolates were detected, 4 of which were also BPR non-susceptible (BPR-NS). In the time-kill experiments, BPR exposure resulted in a potent bactericidal activity (3-5 log10 reduction) at the different concentrations tested. pbp4 gene sequence analysis revealed some mutations that may account for the changes in PBP4 affinity and MIC increase in the 4 BPR-NS strains (MICs 4-16 mg/L): the deletion of an adenine (delA) in the promoter region in all PRAS/BPR-NS strains; 12 different amino acid substitutions, 7 of which were next to the PBP catalytic-sites. The most significant were: T418A, located 6 amino acids (aa) upstream of the catalytic-serine included in the 424STFK427motif I; L475Q, 7 aa upstream of the 482SDN484motif II; V606A and the novel Y605H, 13/14 aa upstream of the 619KTGT622motif III. Taken together, our data showed that elevated BPR MICs were attributable to increased transcription of pbp4 - associated with a single upstream adenine deletion and PBP4 alterations in the catalytic-site motifs – which might interfere with the formation of the BPR/PBP4 complex. pbp4 molecular alterations may account for the changes in PBP4 affinity and MIC increase, without affecting BPR cidal activity. Indeed, our in vitro dynamic analysis by time-kill assays showed that BPR exerted a bactericidal activity against E. faecalis clinical isolates, despite their MDR phenotypes.
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9
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Xu Y, Liu L, Chen Z, Tian X, Chu J. The arthrospore-related gene Acaxl2 is involved in cephalosporin C production in industrial Acremonium chrysogenum by the regulatory factors AcFKH1 and CPCR1. J Biotechnol 2021; 347:26-39. [PMID: 34954288 DOI: 10.1016/j.jbiotec.2021.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 11/20/2022]
Abstract
Cephalosporin C (CPC) production is often accompanied by a typical morphological differentiation of Acremonium chrysogenum, involving the fragmentation of its hyphae into arthrospores. The type I integral plasma membrane protein Axl2 is a central component of the bud site selection system (BSSS), which was identified as the regulatory factor involved in the hyphal septation process and arthrospore formation. Using CRISPR/Cas9 technology and homologous recombination (HR), we inserted an egfp donor DNA sequence into the Acaxl2 locus, causing the generation of the deletion strain Ac-ΔAcaxl2::eGFP from Acremonium chrysogenum FC3-5-23, the industrial producer of CPC. The mycelial morphology of the deletion strain Ac-ΔAcaxl2::eGFP was mainly composed of arthrospores with a characteristic diameter of 2-8 μm, which increased from 75% at 48h to 90% at 72h post culture and were maintained until the end of the fermentation process. However, the deletion strain showed accelerated production of CPC, and the final titer was 5573μg/ml, which was nearly three times higher than that of the control strain FC3-5-23. The up-regulation of genes related to the biosynthesis gene cluster in Ac-ΔAcaxl2::eGFP, especially the "late" genes, was one reason why its CPC production was higher than that of the original strain. Furthermore, compared with FC3-5-23, the more significant increase of genes involved in the BSSS (Acbud3 and Acbud4) in Ac-ΔAcaxl2::eGFP in the late stage of fermentation, may be responsible for this increase in arthrospore formation. Similarily, the transcription of the regulatory factors AcFKH1 and CPCR1 were also markedly increased at this time and may be the factors responsible for the regulation of CPC synthesis. These results indicated that Acaxl2 plays an important role in both arthrospore formation and CPC production, strongly implicating these regulatory factors as having pivotal links between mycelial morphology and secondary metabolite production in high-yielding A. chrysogenum. To the opposite, the axl2 gene knockout of wild strain CGMCC 3.3795 did not significantly influence the CPC production, which reflected the complexity of the secondary metabolic process and the differences in the function of axl2 gene in high- and low-yielding strains.
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Affiliation(s)
- Yan Xu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ling Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zhen Chen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xiwei Tian
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ju Chu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
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10
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Calderini E, Drienovská I, Myrtollari K, Pressnig M, Sieber V, Schwab H, Hofer M, Kourist R. Simple Plug-In Synthetic Step for the Synthesis of (-)-Camphor from Renewable Starting Materials. Chembiochem 2021; 22:2951-2956. [PMID: 34033201 PMCID: PMC8596451 DOI: 10.1002/cbic.202100187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/24/2021] [Indexed: 11/23/2022]
Abstract
Racemic camphor and isoborneol are readily available as industrial side products, whereas (1R)-camphor is available from natural sources. Optically pure (1S)-camphor, however, is much more difficult to obtain. The synthesis of racemic camphor from α-pinene proceeds via an intermediary racemic isobornyl ester, which is then hydrolyzed and oxidized to give camphor. We reasoned that enantioselective hydrolysis of isobornyl esters would give facile access to optically pure isoborneol and camphor isomers, respectively. While screening of a set of commercial lipases and esterases in the kinetic resolution of racemic monoterpenols did not lead to the identification of any enantioselective enzymes, the cephalosporin Esterase B from Burkholderia gladioli (EstB) and Esterase C (EstC) from Rhodococcus rhodochrous showed outstanding enantioselectivity (E>100) towards the butyryl esters of isoborneol, borneol and fenchol. The enantioselectivity was higher with increasing chain length of the acyl moiety of the substrate. The kinetic resolution of isobornyl butyrate can be easily integrated into the production of camphor from α-pinene and thus allows the facile synthesis of optically pure monoterpenols from a renewable side-product.
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Affiliation(s)
- Elia Calderini
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Ivana Drienovská
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Kamela Myrtollari
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
- Henkel AG & Co. KGaAAdhesive Research/BioconjugatesHenkelstr. 6740191DüsseldorfGermany
| | - Michaela Pressnig
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Volker Sieber
- Chemistry of Biogenic ResourcesTechnical University of MunichSchulgasse 1694315StraubingGermany
- Bio, Electro and Chemocatalysis BioCatFraunhofer Institute for Interfacial Engineering and BiotechnologySchulgasse 11a94315StraubingGermany
| | - Helmut Schwab
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
| | - Michael Hofer
- Bio, Electro and Chemocatalysis BioCatFraunhofer Institute for Interfacial Engineering and BiotechnologySchulgasse 11a94315StraubingGermany
| | - Robert Kourist
- Institute of Molecular BiotechnologyGraz University of TechnologyPetersgasse 148010GrazAustria
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11
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Zhgun A, Dumina M, Valiakhmetov A, Eldarov M. The critical role of plasma membrane H+-ATPase activity in cephalosporin C biosynthesis of Acremonium chrysogenum. PLoS One 2020; 15:e0238452. [PMID: 32866191 PMCID: PMC7458343 DOI: 10.1371/journal.pone.0238452] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 08/16/2020] [Indexed: 11/19/2022] Open
Abstract
The filamentous fungus Acremonium chrysogenum is the main industrial producer of cephalosporin C (CPC), one of the major precursors for manufacturing of cephalosporin antibiotics. The plasma membrane H+-ATPase (PMA) plays a key role in numerous fungal physiological processes. Previously we observed a decrease of PMA activity in A. chrysogenum overproducing strain RNCM 408D (HY) as compared to the level the wild-type strain A. chrysogenum ATCC 11550. Here we report the relationship between PMA activity and CPC biosynthesis in A. chrysogenum strains. The elevation of PMA activity in HY strain through overexpression of PMA1 from Saccharomyces cerevisiae, under the control of the constitutive gpdA promoter from Aspergillus nidulans, results in a 1.2 to 10-fold decrease in CPC production, shift in beta-lactam intermediates content, and is accompanied by the decrease in cef genes expression in the fermentation process; the characteristic colony morphology on agar media is also changed. The level of PMA activity in A. chrysogenum HY OE::PMA1 strains has been increased by 50–100%, up to the level observed in WT strain, and was interrelated with ATP consumption; the more PMA activity is elevated, the more ATP level is depleted. The reduced PMA activity in A. chrysogenum HY strain may be one of the selected events during classical strain improvement, aimed at elevating the ATP content available for CPC production.
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Affiliation(s)
- Alexander Zhgun
- Research Center of Biotechnology RAS, Moscow, Russia
- * E-mail:
| | - Mariya Dumina
- Research Center of Biotechnology RAS, Moscow, Russia
| | - Ayrat Valiakhmetov
- Skryabin Institute of Biophysics and Physiology of Microorganisms, RAS, Pushchino, Russia
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12
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Chu L, Chen D, Wang J, Yang Z, Yang Q, Shen Y. Degradation of antibiotics and inactivation of antibiotic resistance genes (ARGs) in Cephalosporin C fermentation residues using ionizing radiation, ozonation and thermal treatment. J Hazard Mater 2020; 382:121058. [PMID: 31450213 DOI: 10.1016/j.jhazmat.2019.121058] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
In present work, the degradation of antibiotic and inactivation of antibiotic resistance genes (ARGs) in cephalosporin C fermentation (CEPF) residues were performed using ionizing radiation, ozonation and thermal treatment. The results showed that the three treatment methods could degrade cephalosporin C effectively, with the removal efficiency of 85.5% for radiation at dose of 100 kGy, 79.9% for ozonation at dosage of 5.2 g O3/L, and 71.9% and 87.3% for thermal treatment at 60 °C and 90 °C for 4 h. The cephalosporin resistance gene tolC was detected in the raw CEPF residues, and its abundance was decrease 74.2% by radiation, 64.6% by ozonation and 26.9%-37.1% by thermal treatment respectively. The presence of protein, glucose and acetate in the CEPF residues had inhibitive influence on the degradation of cephalosporin C by ionizing radiation, and the effect was more significant when the antibiotic concentration was lower. The total content of COD, polysaccharides and protein changed slightly after radiation and thermal treatment, while they were decreased greatly by ozonation. The primary techno-economic analysis showed that the operational cost of ionizing radiation by electron beam at 50 kGy ($5.2/m3) was comparable to thermal treatment ($4.3-7.9/m3), which was more economical than ozonation ($14.6/m3).
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Affiliation(s)
- Libing Chu
- Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing 100084, PR China; Beijing Key Laboratory of Radioactive Waste Treatment, INET, Tsinghua University, Beijing 100084, PR China
| | - Dan Chen
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China
| | - Jianlong Wang
- Collaborative Innovation Center for Advanced Nuclear Energy Technology, INET, Tsinghua University, Beijing 100084, PR China; Beijing Key Laboratory of Radioactive Waste Treatment, INET, Tsinghua University, Beijing 100084, PR China.
| | - Zhilin Yang
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China
| | - Qi Yang
- School of Water Resources and Environment, China University of Geosciences, Beijing 100083, PR China
| | - Yunpeng Shen
- State Environmental Protection Engineering Center for Harmless Treatment and Resource Utilization of Antibiotic Residues, Yili Chuanning Biotechnology Company, Ltd., Xinjiang, 835007, PR China
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13
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Atzori A, Malloci G, Prajapati JD, Basciu A, Bosin A, Kleinekathöfer U, Dreier J, Vargiu AV, Ruggerone P. Molecular Interactions of Cephalosporins with the Deep Binding Pocket of the RND Transporter AcrB. J Phys Chem B 2019; 123:4625-4635. [PMID: 31070373 PMCID: PMC6939625 DOI: 10.1021/acs.jpcb.9b01351] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The drug/proton antiporter AcrB, part of the major efflux pump AcrABZ-TolC in Escherichia coli, is characterized by its impressive ability to transport chemically diverse compounds, conferring a multidrug resistance phenotype. However, the molecular features differentiating between good and poor substrates of the pump have yet to be identified. In this work, we combined molecular docking with molecular dynamics simulations to study the interactions between AcrB and two representative cephalosporins, cefepime and ceftazidime (a good and poor substrate of AcrB, respectively). Our analysis revealed different binding preferences of the two compounds toward the subsites of the large deep binding pocket of AcrB. Cefepime, although less hydrophobic than ceftazidime, showed a higher affinity than ceftazidime for the so-called hydrophobic trap, a region known for binding inhibitors and substrates. This supports the hypothesis that surface complementarity between the molecule and AcrB, more than the intrinsic hydrophobicity of the antibiotic, is a feature required for the interaction within this region. Oppositely, the preference of ceftazidime for binding outside the hydrophobic trap might not be optimal for triggering allosteric conformational changes needed to the transporter to accomplish its function. Altogether, our findings could provide valuable information for the design of new antibiotics less susceptible to the efflux mechanism.
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Affiliation(s)
- Alessio Atzori
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | | | - Andrea Basciu
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Andrea Bosin
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Jürg Dreier
- Basilea Pharmaceutica International Ltd., Grenzacherstrasse 487, 4058 Basel, Switzerland
| | - Attilio V. Vargiu
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
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14
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Evans LE, Krishna A, Ma Y, Webb TE, Marshall DC, Tooke CL, Spencer J, Clarke TB, Armstrong A, Edwards AM. Exploitation of Antibiotic Resistance as a Novel Drug Target: Development of a β-Lactamase-Activated Antibacterial Prodrug. J Med Chem 2019; 62:4411-4425. [PMID: 31009558 PMCID: PMC6511942 DOI: 10.1021/acs.jmedchem.8b01923] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Expression of β-lactamase is the single most prevalent determinant of antibiotic resistance, rendering bacteria resistant to β-lactam antibiotics. In this article, we describe the development of an antibiotic prodrug that combines ciprofloxacin with a β-lactamase-cleavable motif. The prodrug is only bactericidal after activation by β-lactamase. Bactericidal activity comparable to ciprofloxacin is demonstrated against clinically relevant E. coli isolates expressing diverse β-lactamases; bactericidal activity was not observed in strains without β-lactamase. These findings demonstrate that it is possible to exploit antibiotic resistance to selectively target β-lactamase-producing bacteria using our prodrug approach, without adversely affecting bacteria that do not produce β-lactamase. This paves the way for selective targeting of drug-resistant pathogens without disrupting or selecting for resistance within the microbiota, reducing the rate of secondary infections and subsequent antibiotic use.
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Affiliation(s)
- Lindsay E. Evans
- MRC
Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ London, United Kingdom
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
- L.E.E.: e-mail,
| | - Aishwarya Krishna
- MRC
Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ London, United Kingdom
| | - Yajing Ma
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Thomas E. Webb
- Department
of Medicine, Imperial College London, SW7 2AZ London, United Kingdom
| | - Dominic C. Marshall
- Department
of Medicine, Imperial College London, SW7 2AZ London, United Kingdom
| | - Catherine L. Tooke
- School
of Cellular and Molecular Medicine, University
of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - James Spencer
- School
of Cellular and Molecular Medicine, University
of Bristol, Biomedical Sciences Building, University Walk, BS8 1TD Bristol, United Kingdom
| | - Thomas B. Clarke
- MRC
Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ London, United Kingdom
| | - Alan Armstrong
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Andrew M. Edwards
- MRC
Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ London, United Kingdom
- A.M.E.: phone, +44 (0) 20
7594 2072; e-mail,
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15
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Li Z, Hu Y, Liu C, Shen J, Wu J, Li H, Wang K, Zuo J. Performance and microbial community of an expanded granular sludge bed reactor in the treatment of cephalosporin wastewater. Bioresour Technol 2019; 275:94-100. [PMID: 30579106 DOI: 10.1016/j.biortech.2018.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 11/25/2018] [Accepted: 12/01/2018] [Indexed: 05/06/2023]
Abstract
In this study, the anaerobic treatment and microbial characteristics of high-concentration cephalosporin wastewater were studied. A pilot-scale expanded granular sludge bed (EGSB) reactor was designed to treat cephalosporin wastewater, whose diameter, height and effective volume were 0.5 m, 4.9 m, 0.92 m3, respectively. With mixed high-concentration cephalosporin wastewater and municipal wastewater as a substrate, the anaerobic reactor was started and operated 414 days. An average COD removal efficiency of 72% was achieved at an organic loading rate (OLR) of 9.96 kg COD/(m3·d), with a hydraulic retention time (HRT) of 25 h. The average methane content reached 82%. Methanobacterium and Methanomassiliicoccus were predominant archaea in the granular sludge for each of the organic loading rates, and the predominant methane-producing pathway was hydrogenotroph and methylotroph. Those results demonstrated that the EGSB reactor could treat high-concentration cephalosporin wastewater with a unique methane-producing pathway.
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Affiliation(s)
- Zhonghua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Yuying Hu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China; School of Civil Engineering and Architecture, East China Jiao Tong University, Nanchang 330013, PR China
| | - Chuanyang Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jian Shen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jing Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China.
| | - Huaizhi Li
- Laboratory of Reactions and Process Engineering, Université de Lorraine, CNRS, 1, rue Grandville, BP 20451, 54001 Nancy Cedex, France
| | - Kaijun Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jiane Zuo
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, PR China
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16
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Kong XX, Jiang JL, Qiao B, Liu H, Cheng JS, Yuan YJ. The biodegradation of cefuroxime, cefotaxime and cefpirome by the synthetic consortium with probiotic Bacillus clausii and investigation of their potential biodegradation pathways. Sci Total Environ 2019; 651:271-280. [PMID: 30236844 DOI: 10.1016/j.scitotenv.2018.09.187] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
Cephalosporin residues in the environment are a great concern, but bioremediation options do exist. Bacillus clausii T reached a removal rate of 100% within 8 h when challenged with a mixture of cefuroxime (CFX), cefotaxime (CTX), and cefpirome (CPR). The co-culture of B. clausii T and B. clausii O/C displayed a higher removal efficiency for the mixture of CFX, CTX and CPR than a pure culture of B. clausii O/C. B. clausii T alleviated the biotoxicity of CFX and CPR. What's more, the biotoxicity of for CFX and CPR transformation products released by the co-culture of B. clausii T and B. clausii O/C was lower than that in pure cultures. Real-time PCR was applied to detect the changes in the expression levels of the relevant antibiotic-resistance genes of B. clausii T during CFX and CPR degradation. The results indicated that CFX and CPR enhanced the expression of the β-lactamase gene bcl1. Hydrolysis, deacetylation and decarboxylation are likely the major mechanisms of CTX biodegradation by B. clausii. These results demonstrate that B. clausii T is a promising strain for the bioremediation of environmental contamination by CFX, CTX, and CPR.
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Affiliation(s)
- Xiu-Xiu Kong
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China
| | - Jian-Lan Jiang
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China
| | - Bin Qiao
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China
| | - Hong Liu
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China
| | - Jing-Sheng Cheng
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China.
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China; SynBio Research Platform, Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Yaguan Road 135, Jinnan District, Tianjin 300350, PR China
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Sharma AK, Vats P. Evaluation of biochemical and molecular polymorphism in extended spectrum β-lactamases of Mycobacterium tuberculosis clinical isolates. Indian J Tuberc 2019; 66:92-98. [PMID: 30797291 DOI: 10.1016/j.ijtb.2018.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Revised: 02/05/2018] [Accepted: 04/23/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND Tuberculosis (TB) caused 1.8 million deaths worldwide with increased multiple drug resistance (MDR) cases estimated 4.8 lakhs in the year 2015. β-Lactam antibiotics could be a hope for TB treatment. Therefore, in this study, uniformity in the biochemical and molecular nature of β-lactamases was analyzed to evaluate the potential of β-lactam antibiotics as a treatment regimen against Mycobacterium tuberculosis (MTB). MATERIALS AND METHODS β-Lactamase enzymes in 233 MTB clinical isolates along with control H37Rv strain were characterized by enzyme kinetic using nitrocefin and cefotaxime as a substrate, isoelectric points by isoelectric focusing electrophoresis (IEF) and by PCR and Southern blotting. RESULTS Enzyme kinetics showed Km and Vmax for nitrocefin in the range of 56-69μM and 7.00-11IU/lit respectively, for cefotaxime in the range of 0.35-0.59μM and 18-25IU/lit respectively. β-Lactamase showed high affinity for clavulanic acid an inhibitor of Extended-Spectrum β-lactamase enzymes (ESBLs). The pIs of 4.9 and 5.1 were observed for all the MTB clinical isolates and control H37Rv. Southern blotting confirmed the presence of blaC sequence in MTB chromosomal DNA. CONCLUSION This confirmed that MTB β-lactamase enzymes belong to the Class A, group 2be Extended Spectrum β-Lactamases with no biochemical or molecular polymorphism. ESBLs are mainly responsible for resistance against β-lactam antibiotics in MTB. Thus ESBLs could be the potential therapeutic target for TB treatment using β-lactam antibiotics in combination with β-lactamase inhibitors like sulbactam and sodium clavulanate.
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Affiliation(s)
- Asvene K Sharma
- Department of Zoology, M.S. College, (CCS University), Saharanpur 247001, India; Department of Pharmacy, Om Bio-Science & Pharma College, Haridwar 249405, India.
| | - Pratibha Vats
- School of Biotechnology, KIIT University, Bhubaneswar 751024, India.
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18
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Yu X, Zhang M, Zuo J, Shi X, Tang X, Chen L, Li Z. Evaluation of antibiotic resistant lactose fermentative opportunistic pathogenic Enterobacteriaceae bacteria and bla TEM-2 gene in cephalosporin wastewater and its discharge receiving river. J Environ Manage 2018; 228:458-465. [PMID: 30245270 DOI: 10.1016/j.jenvman.2018.09.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/05/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
This study investigated the concentration of cephalosporin, the resistant levels of lactose fermentative opportunistic pathogenic Enterobacteriaceae bacteria (LFOPEB) against seven antibiotics and one cephalosporin-resistant gene in cephalosporin wastewater (CPWW) treatment plant and its discharge receiving river. Although large numbers of bacteria have been removed during the CPWW treatment process, the antibiotic resistant rates of the isolates to β-lactam antibiotics significantly increased (p = 0.032) after treatment, while the percentage of resistant LFOPEB to non-β-lactam antibiotics did not change dramatically. Furthermore, the discharge of the effluent of CPWW treatment plant (CPWWeff) led to an obvious increase in the percentages of β-lactam antibiotic-resistant LFOPEB and relative abundance of the blaTEM-2 gene in the downstream receiving river (RWdown) in comparison with those in the upstream receiving river (RWup). The antibiotic resistant phenotypes of isolates in the influent of CPWW treatment plant (CPWWin), CPWWeff and RWdown appeared to be seriously affected by the cephalosporin residues, which suggested that main antibiotic resistance phenotypes in antibiotic contaminated water were closely associated with its antibiotic composition. Therefore, CPWW treatment process has been proved to result in selective growth of ARB and proliferation of ARG. Besides, CPWWeff was also proved to be an important supplier of ARB and ARG to the receiving river.
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Affiliation(s)
- Xin Yu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; China Academy of Urban Planning & Design, Beijing 100044, China
| | - Mengyu Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; China Urban Construction Design & Research Institute CO.LTD, Beijing 100120, China
| | - Jiane Zuo
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Xuchuan Shi
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xinyao Tang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Lei Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Zaixing Li
- School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
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19
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Poirel L, Kieffer N, Nordmann P. Stability of cefiderocol against clinically significant broad-spectrum oxacillinases. Int J Antimicrob Agents 2018; 52:866-867. [PMID: 30415004 DOI: 10.1016/j.ijantimicag.2018.11.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/29/2018] [Accepted: 11/04/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Laurent Poirel
- Medical and Molecular Microbiology Unit, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland; INSERM European Unit (IAME, France), University of Fribourg, Fribourg, Switzerland; Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, Fribourg, Switzerland.
| | - Nicolas Kieffer
- Medical and Molecular Microbiology Unit, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland; INSERM European Unit (IAME, France), University of Fribourg, Fribourg, Switzerland
| | - Patrice Nordmann
- Medical and Molecular Microbiology Unit, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland; INSERM European Unit (IAME, France), University of Fribourg, Fribourg, Switzerland; Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, Fribourg, Switzerland; Institute for Microbiology, University of Lausanne and University Hospital Centre, Lausanne, Switzerland
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20
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Tadros M, Goneau L, Romaschin A, Jarvis M, Matukas L. Rapid detection of resistance to carbapenems and cephalosporins in Enterobacteriaceae using liquid chromatography tandem mass spectrometry. PLoS One 2018; 13:e0206842. [PMID: 30412608 PMCID: PMC6226185 DOI: 10.1371/journal.pone.0206842] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
Carbapenemase producing Enterobacteriaceae (CPE) are becoming a global healthcare concern. Current laboratory methods for the detection of CPE include screening followed by confirmatory phenotypic and genotypic tests. These processes would generally take ≥72 hours, which could negatively impact patient care and Infection Control practices. To this end, we developed a protocol for rapid resistance testing (RRT) to detect hydrolysis in a panel of beta lactam antibiotics consisting of ampicillin, cefazolin, cefotaxime and imipenem, using liquid chromatography tandem mass spectrometry. Ninety—nine beta lactamase producing Enterobacteriaceae isolates were used to evaluate the RRT method, 54 isolates were CPE and 45 isolates were Class A or AmpC beta lactamase producing Enterobacteriaceae but not carbapenemase producers. We also tested 10 E.coli isolates that were susceptible to ampicillin, cefazolin, cefotaxime and imipenem. Receiver Operating Characteristic (ROC) Curves analysis showed that imipenem had a sensitivity and a specificity of 100% for crabapenemase detection at hydrolysis cut off values that are greater than 50% and less than or equal to 80%. The RRT protocol can be conducted in a time frame of less than 2 hours. This preliminary study shows that the rapid resistance testing protocol might have utility for the rapid detection of CPE. Additional work with a greater number and variety of beta- lactamase producing Enterobacteriaceae isolates is required to validate these preliminary findings.
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Affiliation(s)
- Manal Tadros
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Division of Microbiology, St. Michael’s Hospital, Toronto, Ontario, Canada
- * E-mail:
| | - Lee Goneau
- Department of Microbiology, Public Health Ontario, Toronto, Ontario, Canada
| | | | | | - Larissa Matukas
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Division of Microbiology, St. Michael’s Hospital, Toronto, Ontario, Canada
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21
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Wang Y, Hu P, Li H, Wang Y, Long LK, Li K, Zhang X, Pan Y, Liu G. A Myb transcription factor represses conidiation and cephalosporin C production in Acremonium chrysogenum. Fungal Genet Biol 2018; 118:1-9. [PMID: 29870835 DOI: 10.1016/j.fgb.2018.05.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 11/21/2022]
Abstract
Acremonium chrysogenum is the industrial producer of cephalosporin C (CPC). We isolated a mutant (AC554) from a T-DNA inserted mutant library of A. chrysogenum. AC554 exhibited a reduced conidiation and lack of CPC production. In consistent with it, the transcription of cephalosporin biosynthetic genes pcbC and cefEF was significantly decreased in AC554. Thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) was performed and sequence analysis indicated that a T-DNA was inserted upstream of an open reading frame (ORF) which was designated AcmybA. On the basis of sequence analysis, AcmybA encodes a Myb domain containing transcriptional factor. Observation of red fluorescent protein (RFP) tagged AcMybA showed that AcMybA is naturally located in the nucleus of A. chrysogenum. Transcriptional analysis demonstrated that the AcmybA transcription was increased in AC554. In contrast, the AcmybA deleted mutant (ΔAcmybA) overproduced conidia and CPC. To screen the targets of AcmybA, we sequenced and compared the transcriptome of ΔAcmybA, AC554 and the wild-type strain at different developmental stages. Twelve differentially expressed regulatory genes were identified. Taken together, our results indicate that AcMybA negatively regulates conidiation and CPC production in A. chrysogenum.
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Affiliation(s)
- Ying Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Pengjie Hu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Honghua Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanling Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Liang-Kun Long
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Kuan Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoling Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuanyuan Pan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Gang Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Luscher A, Moynié L, Auguste PS, Bumann D, Mazza L, Pletzer D, Naismith JH, Köhler T. TonB-Dependent Receptor Repertoire of Pseudomonas aeruginosa for Uptake of Siderophore-Drug Conjugates. Antimicrob Agents Chemother 2018; 62:e00097-18. [PMID: 29555629 PMCID: PMC5971595 DOI: 10.1128/aac.00097-18] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
The conjugation of siderophores to antimicrobial molecules is an attractive strategy to overcome the low outer membrane permeability of Gram-negative bacteria. In this Trojan horse approach, the transport of drug conjugates is redirected via TonB-dependent receptors (TBDR), which are involved in the uptake of essential nutrients, including iron. Previous reports have demonstrated the involvement of the TBDRs PiuA and PirA from Pseudomonas aeruginosa and their orthologues in Acinetobacter baumannii in the uptake of siderophore-beta-lactam drug conjugates. By in silico screening, we further identified a PiuA orthologue, termed PiuD, present in clinical isolates, including strain LESB58. The piuD gene in LESB58 is located at the same genetic locus as piuA in strain PAO1. PiuD has a similar crystal structure as PiuA and is involved in the transport of the siderophore-drug conjugates BAL30072, MC-1, and cefiderocol in strain LESB58. To screen for additional siderophore-drug uptake systems, we overexpressed 28 of the 34 TBDRs of strain PAO1 and identified PfuA, OptE, OptJ, and the pyochelin receptor FptA as novel TBDRs conferring increased susceptibility to siderophore-drug conjugates. The existence of a TBDR repertoire in P. aeruginosa able to transport siderophore-drug molecules potentially decreases the likelihood of resistance emergence during therapy.
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Affiliation(s)
- Alexandre Luscher
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Lucile Moynié
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews, Fife, Scotland, United Kingdom
| | | | - Dirk Bumann
- Biozentrum, University of Basel, Basel, Switzerland
| | - Lena Mazza
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | | | - James H Naismith
- School of Chemistry and Biomedical Sciences Research Complex, University of St Andrews, Fife, Scotland, United Kingdom
| | - Thilo Köhler
- Service of Infectious Diseases, University Hospital Geneva, Geneva, Switzerland
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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23
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Woodworth KR, Walters MS, Weiner LM, Edwards J, Brown AC, Huang JY, Malik S, Slayton RB, Paul P, Capers C, Kainer MA, Wilde N, Shugart A, Mahon G, Kallen AJ, Patel J, McDonald LC, Srinivasan A, Craig M, Cardo DM. Vital Signs: Containment of Novel Multidrug-Resistant Organisms and Resistance Mechanisms - United States, 2006-2017. MMWR Morb Mortal Wkly Rep 2018; 67:396-401. [PMID: 29621209 PMCID: PMC5889247 DOI: 10.15585/mmwr.mm6713e1] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND Approaches to controlling emerging antibiotic resistance in health care settings have evolved over time. When resistance to broad-spectrum antimicrobials mediated by extended-spectrum β-lactamases (ESBLs) arose in the 1980s, targeted interventions to slow spread were not widely promoted. However, when Enterobacteriaceae with carbapenemases that confer resistance to carbapenem antibiotics emerged, directed control efforts were recommended. These distinct approaches could have resulted in differences in spread of these two pathogens. CDC evaluated these possible changes along with initial findings of an enhanced antibiotic resistance detection and control strategy that builds on interventions developed to control carbapenem resistance. METHODS Infection data from the National Healthcare Safety Network from 2006-2015 were analyzed to calculate changes in the annual proportion of selected pathogens that were nonsusceptible to extended-spectrum cephalosporins (ESBL phenotype) or resistant to carbapenems (carbapenem-resistant Enterobacteriaceae [CRE]). Testing results for CRE and carbapenem-resistant Pseudomonas aeruginosa (CRPA) are also reported. RESULTS The percentage of ESBL phenotype Enterobacteriaceae decreased by 2% per year (risk ratio [RR] = 0.98, p<0.001); by comparison, the CRE percentage decreased by 15% per year (RR = 0.85, p<0.01). From January to September 2017, carbapenemase testing was performed for 4,442 CRE and 1,334 CRPA isolates; 32% and 1.9%, respectively, were carbapenemase producers. In response, 1,489 screening tests were performed to identify asymptomatic carriers; 171 (11%) were positive. CONCLUSIONS The proportion of Enterobacteriaceae infections that were CRE remained lower and decreased more over time than the proportion that were ESBL phenotype. This difference might be explained by the more directed control efforts implemented to slow transmission of CRE than those applied for ESBL-producing strains. Increased detection and aggressive early response to emerging antibiotic resistance threats have the potential to slow further spread.
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ur Rahman S, Ali T, Ali I, Khan NA, Han B, Gao J. The Growing Genetic and Functional Diversity of Extended Spectrum Beta-Lactamases. Biomed Res Int 2018; 2018:9519718. [PMID: 29780833 PMCID: PMC5892270 DOI: 10.1155/2018/9519718] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 11/17/2022]
Abstract
The β-lactams-a large class of diverse compounds-due to their excellent safety profile and broad antimicrobial spectrum are considered to be the most widely used therapeutic class of antibacterials prescribed in human and veterinary clinical practices. This, unfortunately, has also given rise to a continuous increased resistance globally in health care settings as well as in the community due to their permanent selective force driving diversification of the resistance mechanism. Resistance against β-lactams is increasing rapidly as novel β-lactamases, enzymes that degrade β-lactams, are being discovered each day such as recent emergence of extended spectrum β-lactamases (ESBL) that have the ability to inactivate most of the cephalosporins. The complexity and diversity of ESBL are increasing so rapidly that more than 170 variants have thus far been described for only a single genotype, the blaCTX-M -encoding ESBL. This review is to organize all the current updated literature describing genomic features, organization, and mechanism of resistance and mode of dissemination of all known ESBLs.
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Affiliation(s)
- Sadeeq ur Rahman
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Abdul Wali Khan University, Garden Campus, Khyber Pakhtunkhwa, Pakistan
| | - Tariq Ali
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Ijaz Ali
- Department of Biosciences, COMSATS Institute of Information Technology (CIIT), Bioscience Block, Chak Shahzad Campus, Park Road, Islamabad, Pakistan
| | - Nazir Ahmad Khan
- Department of Animal Nutrition, The University of Agriculture, Peshawar, Pakistan
| | - Bo Han
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jian Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
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25
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Ito A, Sato T, Ota M, Takemura M, Nishikawa T, Toba S, Kohira N, Miyagawa S, Ishibashi N, Matsumoto S, Nakamura R, Tsuji M, Yamano Y. In Vitro Antibacterial Properties of Cefiderocol, a Novel Siderophore Cephalosporin, against Gram-Negative Bacteria. Antimicrob Agents Chemother 2018; 62:e01454-17. [PMID: 29061741 PMCID: PMC5740388 DOI: 10.1128/aac.01454-17] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/04/2017] [Indexed: 02/02/2023] Open
Abstract
Cefiderocol (CFDC; S-649266), a novel parenteral siderophore cephalosporin conjugated with a catechol moiety, has a characteristic antibacterial spectrum with a potent activity against a broad range of aerobic Gram-negative bacterial species, including carbapenem-resistant strains of Enterobacteriaceae and nonfermenting bacteria such as Pseudomonas aeruginosa and Acinetobacter baumannii Cefiderocol has affinity mainly for penicillin-binding protein 3 (PBP3) of Enterobacteriaceae and nonfermenting bacteria similar to that of ceftazidime. A deficiency of the iron transporter PiuA in P. aeruginosa or both CirA and Fiu in Escherichia coli caused 16-fold increases in cefiderocol MICs, suggesting that these iron transporters contribute to the permeation of cefiderocol across the outer membrane. The deficiency of OmpK35/36 in Klebsiella pneumoniae and the overproduction of efflux pump MexA-MexB-OprM in P. aeruginosa showed no significant impact on the activity of cefiderocol.
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Affiliation(s)
- Akinobu Ito
- Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
| | | | - Merime Ota
- Shionogi & Co., Ltd., Toyonaka, Osaka, Japan
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26
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Chen J, Ding Z, Pan H, Cao X. Development of pH-responsive polymer and citrate aqueous two-phase system for extractive bioconversion of cefprozil. Talanta 2017; 174:256-264. [PMID: 28738576 DOI: 10.1016/j.talanta.2017.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/02/2017] [Accepted: 05/11/2017] [Indexed: 11/26/2022]
Abstract
A pH-responsive aqueous two-phase system (pH-ATPS) has been developed by sodium citrate and a recyclable pH-responsive polymer PADB6.8 that can response to the change of pH values. Phase separation mechanism is studied through Low field-NMR. All variables affecting the phase separation are evaluated. Phase characteristics (viscosity, density, interfacial tension) and phase separation kinetic are studied for understanding of separation process and operational parameters in applications. This pH-ATPS has the characters of low interfacial tension, high recovery leading efficient mass transfer and low cost. The proposed system can be used as a mild medium for extractive bioconversion with low cost. We applied this pH-ATPS in extractive bioconversion of cefprozil. Cefprozil is partitioned towards the polymer-rich phase while the substrates tended to be partitioned in the salt-rich phase. Extractive bioconversion of cefprozil in this pH-ATPS can improve yield of the enzymatic process and reduce the product hydrolysis in optimal conditions. The maximal conversion yield of cefprozil in the studied system is 91.0%.
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Affiliation(s)
- Jialing Chen
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zhaoyang Ding
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Hongxia Pan
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xuejun Cao
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, Shanghai 200237, China.
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27
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Li G, Zhong W, Wang R, Chen J, Li Z. Anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues for methane production. J Air Waste Manag Assoc 2017; 67:933-937. [PMID: 28333579 DOI: 10.1080/10962247.2017.1308447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 03/14/2017] [Indexed: 06/06/2023]
Abstract
UNLABELLED Optimum anaerobic conditions of cephalosporin bacterial residues after thermal-alkaline pretreatment were determined by orthogonal experiments. And through biochemical methane potential tests (BMPs) for cephalosporin bacterial residues, the ability for bacterial degradation of cephalosporin was also evaluated. The thermal-alkaline pretreatment with the optimum values of 6% NaOH at 105 °C for 15 min significantly improved digestion performance. With the thermal-alkaline pretreatment, the specific methane yield of the pretreated cephalosporin bacterial residue increased by 254.79% compared with that of the un-pretreated cephalosporin bacterial residue. The results showed that anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues could be one of the options for efficient methane production and waste treatment. IMPLICATIONS This work investigates the thermal-alkaline pretreatment of cephalosporin bacterial residues, which can increase their methane yield by 254.79% compared with no pretreatment. The digestion performance is significantly improved under the condition of 6% NaOH at 105 °C for 15 min. The results show that anaerobic digestion of thermal-alkaline-pretreated cephalosporin bacterial residues could be one of the options for efficient methane production and waste treatment.
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Affiliation(s)
- Guixia Li
- a School of Environmental Science and Engineering , Hebei University of Science and Technology , Shijiazhuang , People's Republic of China
| | - Weizhang Zhong
- a School of Environmental Science and Engineering , Hebei University of Science and Technology , Shijiazhuang , People's Republic of China
| | - Rui Wang
- a School of Environmental Science and Engineering , Hebei University of Science and Technology , Shijiazhuang , People's Republic of China
| | - Jiaqi Chen
- a School of Environmental Science and Engineering , Hebei University of Science and Technology , Shijiazhuang , People's Republic of China
| | - Zaixing Li
- a School of Environmental Science and Engineering , Hebei University of Science and Technology , Shijiazhuang , People's Republic of China
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28
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Yu Y, Zhou Y, Wang Z, Torres OL, Guo R, Chen J. Investigation of the removal mechanism of antibiotic ceftazidime by green algae and subsequent microbic impact assessment. Sci Rep 2017; 7:4168. [PMID: 28646154 PMCID: PMC5482816 DOI: 10.1038/s41598-017-04128-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 05/10/2017] [Indexed: 11/08/2022] Open
Abstract
The present study provides an integrated view of algal removal of the antibiotic ceftazidime and its basic parent structure 7-aminocephalosporanic acid (7-ACA), including contribution analysis, bacteriostatic and aquatic toxic assessment and metabolite verification. 92.70% and 96.07% of the two target compounds was removed after the algal treatment, respectively. The algal removal can be separated into three steps: a rapid adsorption, a slow cell wall-transmission and the final biodegradation. Additionally, while ceftazidime demonstrated an excellent inhibitory effect on Escherichia coli, there was no bacteriostasis introduced after the algal treatment, which could avoid favoring the harmful selective pressure. On the other hand, no significant aquatic impact of the two target compounds on rotifers was observed and it was not enhanced after the algal treatment. To better reveal the mechanism involved, metabolite analyses were performed. Δ-3 ceftazidime and trans-ceftazidime were regarded as the metabolites of ceftazidime and the metabolite of 7-ACA was regarded as a compound which shared the similar structure with 4-chlorocinnamic acid. Our study indicated that the green algae performed a satisfactory growth capacity and played a dominant role for the biodegradation of the target antibiotics, which achieved high removal efficiency and low environmental impact.
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Affiliation(s)
- Ying Yu
- College of Engineering, China Pharmaceutical University, 210009, Nanjing, China
| | - Yangyang Zhou
- College of Engineering, China Pharmaceutical University, 210009, Nanjing, China
| | - Zhiliang Wang
- Jiangsu Key Laboratory of Environmental Engineering, Jiangsu Academic of Environmental Science, 210036, Nanjing, China
| | - Oscar Lopez Torres
- College of Engineering, China Pharmaceutical University, 210009, Nanjing, China
| | - Ruixin Guo
- College of Engineering, China Pharmaceutical University, 210009, Nanjing, China.
| | - Jianqiu Chen
- College of Engineering, China Pharmaceutical University, 210009, Nanjing, China.
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29
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Luo H, Zhu L, Chang Y, Liu X, Liu Z, Sun H, Li X, Yu H, Shen Z. Microenvironmental pH changes in immobilized cephalosporin C acylase during a proton-producing reaction and regulation by a two-stage catalytic process. Bioresour Technol 2017; 223:157-165. [PMID: 27792925 DOI: 10.1016/j.biortech.2016.10.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/09/2016] [Accepted: 10/13/2016] [Indexed: 06/06/2023]
Abstract
Cephalosporin C acylase (CCA), a proton-producing enzyme, was covalently bound on an epoxy-activated porous support. The microenvironmental pH change in immobilized CCA during the reaction was detected using pH-sensitive fluorescein labeling. The high catalytic velocity of the initial stage of conversion resulted in a sharp intraparticle pH gradient, which was likely the key factor relating to low operational stability. Accordingly, a novel strategy for a two-stage catalytic process was developed to reduce the reaction rate of stage I at a low temperature to preserve enzymatic activity and to shorten the duration of catalysis at a high reaction temperature in stage II. The reaction using the two-stage catalytic process (10-37°C shift at 30min) showed significantly improved stability compared with that of the single-temperature reaction at 37°C (29 batches versus five batches, respectively) and a shorter catalytic period than the reaction at 10°C (40min versus 70min, respectively).
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Affiliation(s)
- Hui Luo
- Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
| | - Linlin Zhu
- Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Yanhong Chang
- Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Xiuhong Liu
- Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Zijia Liu
- Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China; Department of Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Hongxu Sun
- Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Xi Li
- Department of Biological Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Huimin Yu
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Zhongyao Shen
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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30
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Ito A, Nishikawa T, Matsumoto S, Yoshizawa H, Sato T, Nakamura R, Tsuji M, Yamano Y. Siderophore Cephalosporin Cefiderocol Utilizes Ferric Iron Transporter Systems for Antibacterial Activity against Pseudomonas aeruginosa. Antimicrob Agents Chemother 2016; 60:7396-7401. [PMID: 27736756 PMCID: PMC5119021 DOI: 10.1128/aac.01405-16] [Citation(s) in RCA: 194] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 09/21/2016] [Indexed: 01/15/2023] Open
Abstract
Cefiderocol (S-649266) is a novel parenteral siderophore cephalosporin conjugated with a catechol moiety at the third-position side chain. The in vitro activity of cefiderocol against Pseudomonas aeruginosa was enhanced under iron-depleted conditions, whereas that of ceftazidime was not affected. The monitoring of [thiazole-14C]cefiderocol revealed the increased intracellular accumulation of cefiderocol in P. aeruginosa cells incubated under iron-depleted conditions compared with those incubated under iron-sufficient conditions. Cefiderocol was shown to have potent chelating activity with ferric iron, and extracellular iron was efficiently transported into P. aeruginosa cells in the presence of cefiderocol as well as siderophores, while enhanced transport of extracellular ferric iron was not observed when one of the hydroxyl groups of the catechol moiety of cefiderocol was replaced with a methoxy group. We conclude that cefiderocol forms a chelating complex with iron, which is actively transported into P. aeruginosa cells via iron transporters, resulting in potent antibacterial activity of cefiderocol against P. aeruginosa.
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Affiliation(s)
- Akinobu Ito
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Toru Nishikawa
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Shuhei Matsumoto
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Hidenori Yoshizawa
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Takafumi Sato
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Rio Nakamura
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Masakatsu Tsuji
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
| | - Yoshinori Yamano
- Drug Discovery and Disease Research Laboratory, Shionogi & Co., Ltd., Osaka, Japan
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Ghazi I, Hamada Y, Nicolau DP. Physical compatibility of tedizolid phosphate with selected i.v. drugs during simulated Y-site administration. Am J Health Syst Pharm 2016; 73:1769-1776. [PMID: 27769972 DOI: 10.2146/ajhp150721] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
PURPOSE The physical compatibility of commonly used agents that could be coadministered in the clinical setting with tedizolid phosphate during Y-site administration was evaluated. METHODS Tedizolid phosphate vials were reconstituted to a final concentration of 0.8 mg/mL. All other drugs were prepared according to manufacturers' recommendations and diluted with 0.9% sodium chloride injection (where applicable) to the highest standard concentrations used clinically. Y-site conditions were simulated in culture tubes by mixing 5 mL of tedizolid phosphate solution with 5 mL of the test drug solutions. The physical characteristics, turbidity, and pH of all admixtures were examined immediately after mixing and at 15, 60, and 120 minutes. Incompatibility was defined as gross precipitation, a positive Tyndall beam test, color changes, or increases in turbidity. RESULTS With simulated Y-site administration, tedizolid phosphate was compatible with 69 of 86 drugs in 0.9% sodium chloride injection, including 24 of 31 antimicrobial agents. Of note, incompatibility was observed immediately after mixing except with ceftaroline and diphenhydramine, whose incompatibility with tedizolid phosphate was apparent after 15 and 60 minutes, respectively. Among the drug classes tested, tedizolid phosphate was compatible only with 1 aminoglycoside (amikacin) and incompatible with 1 echinocandin (caspofungin) and 1 cephalosporin (ceftaroline). In addition, tedizolid phosphate was incompatible with divalent cations (calcium chloride, calcium gluconate, and magnesium sulfate), probably due to precipitation with the phosphate component. A pH change of >1 unit occurred only with epinephrine (at 120 minutes). CONCLUSION Tedizolid phosphate 0.8 mg/mL in 0.9% sodium chloride injection was physically compatible with 69 of 86 study drugs during simulated Y-site administration.
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Affiliation(s)
- Islam Ghazi
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT
| | - Yukihiro Hamada
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT.
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32
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Srinivas NR. Interspecies scaling of excretory amounts using allometry - retrospective analysis with rifapentine, aztreonam, carumonam, pefloxacin, miloxacin, trovafloxacin, doripenem, imipenem, cefozopran, ceftazidime, linezolid for urinary excretion and rifapentine, cabotegravir, and dolutegravir for fecal excretion. Xenobiotica 2016; 46:784-92. [PMID: 26711252 DOI: 10.3109/00498254.2015.1121554] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 11/11/2015] [Accepted: 11/15/2015] [Indexed: 11/13/2022]
Abstract
1. Interspecies allometry scaling for prediction of human excretory amounts in urine or feces was performed for numerous antibacterials. Antibacterials used for urinary scaling were: rifapentine, pefloxacin, trovafloxacin (Gr1/low; <10%); miloxacin, linezolid, PNU-142300 (Gr2/medium; 10-40%); aztreonam, carumonam, cefozopran, doripenem, imipenem, and ceftazidime (Gr3/high; >50%). Rifapentine, cabotegravir, and dolutegravir was used for fecal scaling (high; >50%). 2. The employment of allometry equation: Y = aW(b) enabled scaling of urine/fecal amounts from animal species. Corresponding predicted amounts were converted into % recovery by considering the respective human dose. Comparison of predicted/observed values enabled fold difference and error calculations (mean absolute error [MAE] and root mean square error [RMSE]). Comparisons were made for urinary/fecal data; and qualitative assessment was made amongst Gr1/Gr2/Gr3 for urine. 3. Average correlation coefficient for the allometry scaling was >0.995. Excretory amount predictions were largely within 0.75- to 1.5-fold differences. Average MAE and RMSE were within ±22% and 23%, respectively. Although robust predictions were achieved for higher urinary/fecal excretion (>50%), interspecies scaling was applicable for low/medium excretory drugs. 4. Based on the data, interspecies scaling of urine or fecal excretory amounts may be potentially used as a tool to understand the significance of either urinary or fecal routes of elimination in humans in early development.
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Affiliation(s)
- Nuggehally R Srinivas
- a Department of Integrated Drug Development , Suramus Bio , Bangalore , Karnataka , India
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Farhat NM, Hutchinson LS, Peters M. Elevated International Normalized Ratio values in a patient receiving warfarin and ceftaroline. Am J Health Syst Pharm 2016; 73:56-9. [PMID: 26721534 DOI: 10.2146/ajhp140897] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
PURPOSE The case of a patient whose International Normalized Ratio (INR) became elevated due to a probable interaction between ceftaroline and warfarin is reported. SUMMARY A 65-year-old African-American man developed an INR of >18.0 after completing 12 days of ceftaroline therapy for the treatment of cellulitis while taking warfarin therapy. The patient was on warfarin due to his history of deep vein thrombosis of a lower extremity and pulmonary embolism, and his INR was consistently therapeutic for approximately 2 years before ceftaroline therapy. The patient reported no known drug allergies, had no history of adverse drug reactions, and had no recent changes in medications or diet. Phytonadione was administered, and the patient's INR began to decrease, returning to a therapeutic range of 2.30 after approximately 48 hours, at which time warfarin was restarted. After six days of hospitalization, the patient was discharged on his previous regimen of warfarin 7.5 mg orally once daily, with a therapeutic INR of 2.11. His cellulitis had resolved, so no further antibiotic therapy was warranted. To determine the likelihood of the drug interaction between warfarin and ceftaroline in this patient, the Drug Interaction Probability Scale of Horn and colleagues was applied and yielded a score of 6, indicating a probable likelihood of an interaction. Rechallenge was not attempted, as the patient's cellulitis had resolved and there were no evident signs or symptoms of infection. CONCLUSION A 65-year-old man experienced an increase in INR values after the addition of ceftaroline to his medication regimen.
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Affiliation(s)
- Nada M Farhat
- Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, and Department of Pharmacy, Henry Ford Hospital, Detroit, MI
| | | | - Michael Peters
- Department of Pharmacy, Henry Ford Hospital, Detroit, MI
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Eldarov M A, Sklyarenko AV, Mardanov AV, Beletsky AV, Zhgun AA, Dumina MV, Medvedeva NV, Satarova DE, Ravin NV, Yarockii SV. [Cephalosporin-Acid Synthetase of Escherichia coli Strain VKPM B-10182: Genomic Context, Gene Identification, Producer Strain Production]. Prikl Biokhim Mikrobiol 2015; 51:465-471. [PMID: 26596082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An enzyme of cephalosporin-acid synthetase produced by the E. coli strain VKPM B-10182 has specificity for the synthesis of β-lactam antibiotics of the cephalosporin acids class (cefazolin, cefalotin, cefezole etc.). A comparison of the previously determined genomic sequence of E. coli VKPM B-10182 with a genome of the parent E. coli strain ATCC 9637 was performed. Multiple mutations indicating the long selection history of the strain were detected, including mutations in the genes of RNase and β-lactamases that could enhance the level of enzyme synthesis and reduce the degree of degradation of the synthesized cephalosporin acids. The CASA gene--a direct homolog of the penicillin G-acylase gene--was identified by bioinformatics methods. The homology of the gene was confirmed by gene cloning and the expression and determination of its enzymatic activity in the reaction of cefazolin synthesis. The CASA gene was isolated and cloned into the original expression vector, resulting in an effective E. coli BL2l(DE3) pMD0107 strain producing CASA.
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Ghavami A, Labbé G, Brem J, Goodfellow VJ, Marrone L, Tanner CA, King DT, Lam M, Strynadka NCJ, Pillai DR, Siemann S, Spencer J, Schofield CJ, Dmitrienko GI. Assay for drug discovery: Synthesis and testing of nitrocefin analogues for use as β-lactamase substrates. Anal Biochem 2015; 486:75-7. [PMID: 26142222 DOI: 10.1016/j.ab.2015.06.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 06/11/2015] [Accepted: 06/24/2015] [Indexed: 11/17/2022]
Abstract
We report on the synthesis of three nitrocefin analogues and their evaluation as substrates for the detection of β-lactamase activity. These compounds are hydrolyzed by all four Ambler classes of β-lactamases. Kinetic parameters were determined with eight different β-lactamases, including VIM-2, NDM-1, KPC-2, and SPM-1. The compounds do not inhibit the growth of clinically important antibiotic-resistant gram-negative bacteria in vitro. These chromogenic compounds have a distinct absorbance spectrum and turn purple when hydrolyzed by β-lactamases. One of these compounds, UW154, is easier to synthesize from commercial starting materials than nitrocefin and should be significantly less expensive to produce.
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Affiliation(s)
- Ahmad Ghavami
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Geneviève Labbé
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jürgen Brem
- Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, UK
| | - Valerie J Goodfellow
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Laura Marrone
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Carol A Tanner
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Dustin T King
- Department of Biochemistry and Molecular Biology and Center for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Melinda Lam
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Center for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Dylan R Pillai
- Departments of Pathology & Laboratory Medicine, Medicine, and Microbiology & Infectious Diseases, University of Calgary, Calgary, Alberta T2L 2K8, Canada
| | - Stefan Siemann
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario P3E 2C6, Canada
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, UK
| | | | - Gary I Dmitrienko
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
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Selvi A, Das D, Das N. Potentiality of yeast Candida sp. SMN04 for degradation of cefdinir, a cephalosporin antibiotic: kinetics, enzyme analysis and biodegradation pathway. Environ Technol 2015; 36:3112-3124. [PMID: 26000889 DOI: 10.1080/09593330.2015.1054318] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 05/19/2015] [Indexed: 06/04/2023]
Abstract
A new yeast strain isolated from the pharmaceutical wastewater was capable of utilizing cefdinir as a sole carbon source for their growth in mineral medium. The yeast was identified and named as Candida sp. SMN04 based on morphology and 18S-ITS-D1/D2/D3 rRNA sequence analysis. The interaction between factors pH (3.0-9.0), inoculum dosage (1-7%), time (1-11 day) and cefdinir concentration (50-450 mg/L) was studied using a Box-Behnken design. The factors were studied as a result of their effect on cell dry weight (R1; g/L), extended spectrum β-lactamase (ESBL) assay (R2; mm), P450 activity (R3; U/mL) and degradation (R4; %). Maximum values of R1, R2, R3 and R4 were obtained at central values of all the parameters. The isolated yeast strain efficiently degraded 84% of 250 mg L⁻¹ of cefdinir within 6 days with a half-life of 2.97 days and degradation rate constant of 0.2335 per day. Pseudo-first-order model efficiently described the process. Among the various enzymes tested, the order of activity at the end of Day 4 was noted to be: cytochrome P450 (1.76 ± 0.03) > NADPH reductase (1.51 ± 0.20) > manganese peroxidase and amylase (0.66 ± 0.15; 0.66 ± 0.70). Intermediates were successfully characterized by liquid chromatography-mass spectrometry. The opening of the β-lactam ring involving ESBL activity was considered as one of the major steps in the cefdinir degradation process. Fourier transform-infrared spectroscopy analysis showed the absence of spectral vibrations between 1766 and 1519 cm⁻¹ confirming the complete removal of lactam ring during cefdinir degradation. The results of the present study are promising for the use of isolated yeast Candida sp. SMN04 as a potential bioremediation agent.
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Affiliation(s)
- A Selvi
- a School of Bio Sciences and Technology , VIT University , Vellore 632014 , Tamil Nadu , India
| | - Devlina Das
- a School of Bio Sciences and Technology , VIT University , Vellore 632014 , Tamil Nadu , India
| | - Nilanjana Das
- a School of Bio Sciences and Technology , VIT University , Vellore 632014 , Tamil Nadu , India
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Zalewski P, Skibiński R, Paczkowska M, Garbacki P, Talaczyńska A, Cielecka-Piontek J, Jelińska A. Stability of cefozopran hydrochloride in aqueous solutions. Drug Dev Ind Pharm 2015; 42:572-7. [PMID: 26079426 DOI: 10.3109/03639045.2015.1054834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/20/2015] [Indexed: 01/30/2023]
Abstract
The influence of pH on the stability of cefozopran hydrochloride (CZH) was investigated in the pH range of 0.44-13.00. Six degradation products were identified with a hybrid ESI-Q-TOF mass spectrometer. The degradation of CZH as a result of hydrolysis was a pseudo-first-order reaction. As general acid-base hydrolysis of CZH was not occurred in the solutions of hydrochloric acid, sodium hydroxide, acetate, borate and phosphate buffers, kobs = kpH because specific acid-base catalysis was observed. Specific acid-base catalysis of CZH consisted of the following reactions: hydrolysis of CZH catalyzed by hydrogen ions (kH+), hydrolysis of dications (k1H2O), monocations (k2H2O) and zwitter ions (k3H2O) and hydrolysis of zwitter ions (k1OH-) and monoanions (k2OH-) of CZH catalyzed by hydroxide ions. The total rate of the reaction was equal to the sum of partial reactions: [Formula: see text]. CZH similarly like other fourth generation cephalosporin was most stable at slightly acidic and neutral pH and less stable in alkaline pH. The cleavage of the β-lactam ring resulting from a nucleophilic attack on the carbonyl carbon in the β-lactam moiety is the preferred degradation pathway of β-lactam antibiotics in aqueous solutions.
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Affiliation(s)
- Przemysław Zalewski
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
| | - Robert Skibiński
- b Department of Medicinal Chemistry , Medical University of Lublin , Jaczewskiego , Lublin , Poland
| | - Magdalena Paczkowska
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
| | - Piotr Garbacki
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
| | - Alicja Talaczyńska
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
| | - Judyta Cielecka-Piontek
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
| | - Anna Jelińska
- a Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Poznan University of Medical Sciences , Grunwaldzka , Poznań , Poland and
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Mura T, Kawamura K, Wachino JI, Shibayama K, Arakawa Y. Development of a novel chromogenic method, Penta-well test, for rapid prediction of β-lactamase classes produced in clinical Enterobacteriaceae isolates. Diagn Microbiol Infect Dis 2015; 83:25-9. [PMID: 26141493 DOI: 10.1016/j.diagmicrobio.2015.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/28/2015] [Accepted: 06/02/2015] [Indexed: 01/09/2023]
Abstract
We developed a novel chromogenic method, Penta-well test, which enables the rapid detection and classification of β-lactamases in clinical Enterobacteriaceae isolates. This test is based on a combination of nitrocefin and 3 β-lactamase inhibitors specific to classes A, B, and/or C, with nitrocefin hydrolysis by β-lactamases being assessed by optical density measurements at 490 nm. When the cutoff value for each β-lactamase class was determined (0.09, 0.4, and 0.55 for class A, class B, and class C β-lactamase producers, respectively), the sensitivity and specificity of classification were 93.5% and 68.8% for class A, 93.8% and 100% for class B, and 86.7% and 100% for class C, respectively. Moreover, this method allowed accurate β-lactamase classification in 20 of 23 (87.0%) isolates producing plural class of β-lactamases. Thus, the Penta-well test can provide information that would be useful in the accurate detection and classification of β-lactamases produced by causative bacteria.
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Affiliation(s)
- Tatsuki Mura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan.
| | - Kumiko Kawamura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20, Daikominami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan.
| | - Jun-ichi Wachino
- Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
| | - Keigo Shibayama
- Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.
| | - Yoshichika Arakawa
- Department of Bacteriology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi, 466-8550, Japan; Department of Bacteriology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan.
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Abstract
Although the role of general bacterial porins is well established as main pathway for polar antibiotics, the molecular details of their mode-of-action are still under debate. Using molecular dynamics simulations and water as a probe, we demonstrated the strong ordering of water molecules, differently tuned along the axis of diffusion in the transversal direction. Preserved features and important differences were characterized for different channels, allowing to put forward a general model for molecular filtering. The intrinsic electric field, responsible for water ordering, (i) filters those dipolar molecules that can compensate the entropy decrease by dipole alignment in the restricted region and (ii) might create an additional barrier by changing direction when escaping from the restricted region. We tested this model using two antibiotics, cefepime and cefotaxime, through metadynamics free energy calculations. A rational drug design should take this into account for screening molecules with improved permeation properties.
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Affiliation(s)
- Silvia Acosta-Gutierrez
- †Department of Physics, University of Cagliari, Cittadella Universitaria di Monserrato, S.P.8-km 0.700, 09042 Monserrato, Cagliari, Italy
| | - Mariano Andrea Scorciapino
- ‡Department of Biomedical Sciences, Biochemistry Unit, University of Cagliari, Cittadella Universitaria di Monserrato, S.P.8-km 0.700, 09042 Monserrato, Cagliari, Italy
| | - Igor Bodrenko
- †Department of Physics, University of Cagliari, Cittadella Universitaria di Monserrato, S.P.8-km 0.700, 09042 Monserrato, Cagliari, Italy
| | - Matteo Ceccarelli
- †Department of Physics, University of Cagliari, Cittadella Universitaria di Monserrato, S.P.8-km 0.700, 09042 Monserrato, Cagliari, Italy
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Huang PJJ, Pautler R, Shanmugaraj J, Labbé G, Liu J. Inhibiting the VIM-2 Metallo-β-Lactamase by Graphene Oxide and Carbon Nanotubes. ACS Appl Mater Interfaces 2015; 7:9898-9903. [PMID: 25897818 DOI: 10.1021/acsami.5b01954] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Metallo-β-lactamases (MBLs) degrade a broad spectrum of antibiotics including the latest carbapenems. So far, limited success has been achieved in developing its inhibitors using small organic molecules. VIM-2 is one of the most studied and important MBLs. In this work, we screened 10 nanomaterials, covering a diverse range of surface properties including charge, hydrophobicity, and specific chemical bonding. Among these, graphene oxide and carbon nanotubes are the most potent inhibitors, while most other materials do not show much inhibition effect. The inhibition is noncompetitive and is attributed to the hydrophobic interaction with the enzyme. Adsorption of VIM-2 was further probed using protein displacement assays where it cannot displace or be displaced by bovine serum albumin (BSA). This information is useful for rational design inhibitors for MBLs and more specific inhibition might be achieved by further surface modifications on these nanocarbons.
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Affiliation(s)
- Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Rachel Pautler
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Jenitta Shanmugaraj
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Geneviève Labbé
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Affiliation(s)
- W Cullmann
- Bürgerhospital/Zentrallabor, Stuttgart, Deutschland
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46
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Erickson BD, Elkins CA, Mullis LB, Heinze TM, Wagner RD, Cerniglia CE. A metallo-β-lactamase is responsible for the degradation of ceftiofur by the bovine intestinal bacterium Bacillus cereus P41. Vet Microbiol 2014; 172:499-504. [PMID: 24972871 DOI: 10.1016/j.vetmic.2014.05.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 05/20/2014] [Accepted: 05/29/2014] [Indexed: 11/27/2022]
Abstract
Ceftiofur is a highly effective veterinary cephalosporin, yet it is rapidly degraded by bacteria in the gut. The goal of this work was to directly determine the mechanism of ceftiofur degradation by the bovine intestinal isolate Bacillus cereus P41. B. cereus P41 was isolated from the feces of a cow that had not been treated with cephalosporins, and was found to rapidly degrade ceftiofur in culture. Analysis of spent culture media by HPLC/UV and HPLC/MS revealed one major metabolite of ceftiofur, with a negative ion m/z of 127. Comparison of ceftiofur, ceftriaxone, and cefpodoxime degradation suggested that the major stable ceftiofur metabolite was the thiofuroic acid group eliminated from the C-3 position of the drug after hydrolysis by β-lactamase. Genomic DNA from B. cereus P41 was cloned into Escherichia coli, and the transformants were screened for growth in the presence of ceftiofur. DNA sequencing of the plasmid pHSG299-BC-3 insert revealed the presence of a gene encoding a metallo-β-lactamase. Incubation of ceftiofur with either the E. coli transformant or a commercial B. cereus metallo-β-lactamase showed degradation of the drug and formation of the same major metabolite produced by B. cereus P41. These data demonstrate that a metallo-β-lactamase plays a major role in the degradation of ceftiofur by the bovine intestinal bacterium B. cereus P41.
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Affiliation(s)
- Bruce D Erickson
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR, United States.
| | - Christopher A Elkins
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR, United States
| | - Lisa B Mullis
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR, United States
| | - Thomas M Heinze
- Division of Biochemical Toxicology, National Center for Toxicological Research, Jefferson, AR, United States
| | - R Doug Wagner
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR, United States
| | - Carl E Cerniglia
- Division of Microbiology, National Center for Toxicological Research, Jefferson, AR, United States
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Li Q, Huang X, Zhu Y. Evaluation of active designs of cephalosporin C acylase by molecular dynamics simulation and molecular docking. J Mol Model 2014; 20:2314. [PMID: 24935111 DOI: 10.1007/s00894-014-2314-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 05/19/2014] [Indexed: 01/04/2023]
Abstract
Optimization to identify the global minimum energy conformation sequence in in silico enzyme design is computationally non-deterministic polynomial-time (NP)-hard, with the search time growing exponentially as the number of design sites increases. This drawback forces the modeling of protein-ligand systems to adopt discrete amino acid rotamers and ligand conformers, as well as continuum solvent treatment of the environment; however, such compromises produce large numbers of false positives in sequence selection. In this report, cephalosporin acylase, which catalyzes the hydrolytic reaction of cephalosporin C to 7-aminocephalosporanic acid, was used to investigate the dynamic features of active-site-transition-state complex structures using molecular dynamics (MD) simulations to potentially eliminate false positives. The molecular docking between cephalosporin C and wild type acylase N176 and its eight mutants showed that the rate-limiting step in the hydrolytic reaction of cephalosporin C is the acylation process. MD simulations of the active-site-transition-state complex structures of the acylation processes for N176 and its eight mutants showed that the geometrical constraints between catalytic residues and small molecule transition states are always well maintained during the 20 ns simulation for mutants with higher activities, and more hydrogen bonds between binding residues and functional groups of the ligand side chain in the active pocket are formed for mutants with higher activities. The conformations of the ligand transition states were changed greatly after the simulation. This indicates that the hydrogen bond network between the ligand and protein could be improved to enhance the activity of cephalosporin C acylase in subsequent design.
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Affiliation(s)
- Qing Li
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, People's .Republic of China
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Feng S, Chiesa OA, Kijak P, Chattopadhaya C, Lancaster V, Smith EA, Girard L, Sklenka S, Li H. Determination of ceftiofur metabolite desfuroylceftiofur cysteine disulfide in bovine tissues using liquid chromatography-tandem mass spectrometry as a surrogate marker residue for ceftiofur. J Agric Food Chem 2014; 62:5011-5019. [PMID: 24819974 DOI: 10.1021/jf405423e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Ceftiofur is a widely used cephalosporin β-lactam antibiotic with frequently reported residue violations. This paper reports a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determining a ceftiofur metabolite, desfuroylceftiofur cysteine disulfide (DCCD), in bovine kidney, liver, and muscle tissues. Incurred tissue samples were obtained from dosed animals and analyzed to evaluate the utility of the method. For kidney, the target tissue, the method utilized a simple extraction with phosphate buffer followed by solid phase extraction (SPE) cleanup. For liver and muscle, acetonitrile and hexane were used to remove most proteins and fat from the initial buffer extract before the SPE cleanup. Method accuracy was between 97 and 107%, and the coefficient of variation was between 3.4 and 11.0% for all three types of tissues. The relationship between the new and regulatory methods for bovine kidney was established. It was concluded that DCCD is a suitable surrogate marker residue for ceftiofur in bovine kidney.
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Affiliation(s)
- Shixia Feng
- Center for Veterinary Medicine, Office of Research, U.S. Food and Drug Administration, 8401 Muirkirk Road, Laurel, Maryland 20708, United States
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Dumina MV, Zhgun AA, Kerpichnikov IV, Domracheva AG, Novak MI, Valiakhmetov AI, Knorre DA, Severin FF, Él'darov MA, Bartoshevich IÉ. [Functional characteristic of the CefT transporter of the MFS family involved in the transportation of beta-lactam antibiotics in Acremonium chrysogenum and Saccharomyces cerevisiae]. ACTA ACUST UNITED AC 2014; 49:372-81. [PMID: 24455863 DOI: 10.7868/s0555109913040041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Vectors for the expression of the CefT transporter of the MFS family in Acremonium chrysogenum--a producer of beta-lactam antibiotic cephalosporin C--and in Saccharomyces cerevisiae as a fusion with the cyan fluorescent protein (CFP) have been created. The subcellular localization of the CefT-CFP hybrid protein in yeast cells has been investigated. It was shown that the CefT-CFP hybrid protein is capable of complementation of the qdr3, tpo 1, and tpo3 genes encoding for orthologous MFS transporters of Saccharomycetes, making the corresponding strains resistant to spermidine, ethidium bromide, and hygromycin B. High-yield strain VKM F-4081D of A. chrysogenum, expressing the cefT-cfp fusion, was obtained by an agrobacteria conjugated transfer. It was also shown that the constitutive expression of cefT in A. chrysogenum VKM F-4081D led to a change in the biosynthetic profiles of cephalosporin C and its precursors. This resulted in a 25-35% decrease in the finite product accumulated in the cultural liquid with a simultaneous increase in the concentration of its intermediators.
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Otero LH, Rojas-Altuve A, Llarrull LI, Carrasco-López C, Kumarasiri M, Lastochkin E, Fishovitz J, Dawley M, Hesek D, Lee M, Johnson JW, Fisher JF, Chang M, Mobashery S, Hermoso JA. How allosteric control of Staphylococcus aureus penicillin binding protein 2a enables methicillin resistance and physiological function. Proc Natl Acad Sci U S A 2013; 110:16808-13. [PMID: 24085846 PMCID: PMC3800995 DOI: 10.1073/pnas.1300118110] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression of penicillin binding protein 2a (PBP2a) is the basis for the broad clinical resistance to the β-lactam antibiotics by methicillin-resistant Staphylococcus aureus (MRSA). The high-molecular mass penicillin binding proteins of bacteria catalyze in separate domains the transglycosylase and transpeptidase activities required for the biosynthesis of the peptidoglycan polymer that comprises the bacterial cell wall. In bacteria susceptible to β-lactam antibiotics, the transpeptidase activity of their penicillin binding proteins (PBPs) is lost as a result of irreversible acylation of an active site serine by the β-lactam antibiotics. In contrast, the PBP2a of MRSA is resistant to β-lactam acylation and successfully catalyzes the DD-transpeptidation reaction necessary to complete the cell wall. The inability to contain MRSA infection with β-lactam antibiotics is a continuing public health concern. We report herein the identification of an allosteric binding domain--a remarkable 60 Å distant from the DD-transpeptidase active site--discovered by crystallographic analysis of a soluble construct of PBP2a. When this allosteric site is occupied, a multiresidue conformational change culminates in the opening of the active site to permit substrate entry. This same crystallographic analysis also reveals the identity of three allosteric ligands: muramic acid (a saccharide component of the peptidoglycan), the cell wall peptidoglycan, and ceftaroline, a recently approved anti-MRSA β-lactam antibiotic. The ability of an anti-MRSA β-lactam antibiotic to stimulate allosteric opening of the active site, thus predisposing PBP2a to inactivation by a second β-lactam molecule, opens an unprecedented realm for β-lactam antibiotic structure-based design.
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Affiliation(s)
- Lisandro H. Otero
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Alzoray Rojas-Altuve
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Leticia I. Llarrull
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Cesar Carrasco-López
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
| | - Malika Kumarasiri
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Elena Lastochkin
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jennifer Fishovitz
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Matthew Dawley
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jarrod W. Johnson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Mayland Chang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
| | - Juan A. Hermoso
- Departamento de Cristalografía y Biología Estructural, Instituto de Química-Física “Rocasolano,” Consejo Superior de Investigaciones Cientificas, 28006 Madrid, Spain; and
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