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Development of a new spectrophotometric assay for rapid detection and differentiation of KPC, MBL and OXA-48 carbapenemase-producing Klebsiella pneumoniae clinical isolates. Int J Antimicrob Agents 2020; 56:106211. [PMID: 33172591 DOI: 10.1016/j.ijantimicag.2020.106211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/13/2020] [Accepted: 10/17/2020] [Indexed: 11/21/2022]
Abstract
The increased prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has made essential the design of quicker tests for CPE detection. In the present study, a simple and rapid assay was developed based on measurement of the hydrolytic activity of imipenem at a final concentration of 65 µg/mL (100 µM) through ultraviolet-visible (UV-Vis) spectrophotometry. All measurements were conducted at 297 nm. A total of 83 carbapenem-non-susceptible CPE, consisting of Klebsiella pneumoniae clinical isolates and genotypically characterised as KPC-, VIM-, NDM- or OXA-48-producers, were tested. For comparison, 30 carbapenem-non-susceptible clinical isolates, consisting of Escherichia coli and K. pneumoniae and genotypically confirmed as non-CPE, were also examined. The spectrophotometric assay enabled efficient discrimination of CPE from non-CPE isolates even in 45 min (P < 0.0001). Moreover, the presence of phenylboronic acid (PBA) or ethylene diamine tetra-acetic acid (EDTA) in the reaction mixture was able to inhibit the hydrolytic capacity of KPC- or metallo-β-lactamase (MBL)-producers, respectively, while the hydrolytic activity of OXA-48-producing strains was not affected by the presence of these inhibitors (P < 0.001). The newly developed assay presented 100% sensitivity and specificity to detect and differentiate KPC-, MBL- and OXA-48-producers compared with genotypic characterisation. Thus, the proposed spectrophotometric method can be considered as an easy, fast, accurate and cost-effective diagnostic tool for screening carbapenem-non-susceptible K. pneumoniae isolates in the clinical laboratory.
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Zamperini C, Maccari G, Deodato D, Pasero C, D'Agostino I, Orofino F, De Luca F, Dreassi E, Docquier JD, Botta M. Identification, synthesis and biological activity of alkyl-guanidine oligomers as potent antibacterial agents. Sci Rep 2017; 7:8251. [PMID: 28811659 PMCID: PMC5557985 DOI: 10.1038/s41598-017-08749-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 07/17/2017] [Indexed: 11/09/2022] Open
Abstract
In the last two decades, the repertoire of clinically effective antibacterials is shrinking due to the rapidly increasing of multi-drug-resistant pathogenic bacteria. New chemical classes with innovative mode of action are required to prevent a return to the pre-antibiotic era. We have recently reported the identification of a series of linear guanidine derivatives and their antibacterial properties. A batch of a promising candidate for optimization studies (compound 1) turned out to be a mixture containing two unknown species with a better biological activity than the pure compound. This serendipitous discovery led us to investigate the chemical nature of the unknown components of the mixture. Through MS analysis coupled with design and synthesis we found that the components were spontaneously generated oligomers of the original compound. Preliminary biological evaluations eventually confirmed the broad-spectrum antibacterial activity of this new family of molecules. Interestingly the symmetric dimeric derivative (2) exhibited the best profile and it was selected as lead compound for further studies.
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Affiliation(s)
- C Zamperini
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy.,Lead Discovery Siena s.r.l., Via Vittorio Alfieri 31, I-53019, Castelnuovo, Berardenga, Italy
| | - G Maccari
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - D Deodato
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - C Pasero
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - I D'Agostino
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - F Orofino
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - F De Luca
- Department of Medical Biotechnology, University of Siena, I-53100, Siena, Italy
| | - E Dreassi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy
| | - J D Docquier
- Lead Discovery Siena s.r.l., Via Vittorio Alfieri 31, I-53019, Castelnuovo, Berardenga, Italy.,Department of Medical Biotechnology, University of Siena, I-53100, Siena, Italy
| | - M Botta
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, I-53100, Siena, Italy. .,Lead Discovery Siena s.r.l., Via Vittorio Alfieri 31, I-53019, Castelnuovo, Berardenga, Italy. .,Sbarro Institute for Cancer Research and Molecular Medicine, Temple University, BioLife Science Building, Suite 333, 1900 North 12th Street, Philadelphia, Pennsylvania, 19122, United States of America.
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Abstract
β-Lactamases, the enzymes that hydrolyze β-lactam antibiotics, remain the greatest threat to the usage of these agents. In this review, the mechanism of hydrolysis is discussed for both those enzymes that use serine at the active site and those that require divalent zinc ions for hydrolysis. The β-lactamases now include >2000 unique, naturally occurring amino acid sequences. Some of the clinically most important of these are the class A penicillinases, the extended-spectrum β-lactamases (ESBLs), the AmpC cephalosporinases, and the carbapenem-hydrolyzing enzymes in both the serine and metalloenzyme groups. Because of the versatility of these enzymes to evolve as new β-lactams are used therapeutically, new approaches to antimicrobial therapy may be required.
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Affiliation(s)
- Robert A Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio 44120.,Departments of Pharmacology, Molecular Biology and Microbiology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44120
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Characterization of BKC-1 class A carbapenemase from Klebsiella pneumoniae clinical isolates in Brazil. Antimicrob Agents Chemother 2015; 59:5159-64. [PMID: 26055384 DOI: 10.1128/aac.00158-15] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/05/2015] [Indexed: 01/14/2023] Open
Abstract
Three Klebsiella pneumoniae clinical isolates demonstrating carbapenem resistance were recovered from different patients hospitalized at two medical centers in São Paulo, Brazil. Resistance to all β-lactams, quinolones, and some aminoglycosides was observed for these isolates that were susceptible to polymyxin B. Carbapenem hydrolysis, which was inhibited by clavulanic acid, was observed for all K. pneumoniae isolates that belonged to the same pulsed-field gel electrophoresis (PFGE) type and a novel sequence type (ST), ST1781 (clonal complex 442 [CC442]). A 10-kb nonconjugative incompatibility group Q (IncQ) plasmid, denominated p60136, was transferred to Escherichia coli strain TOP10 cells by electroporation. The full sequencing of p60136 showed that it was composed of a mobilization system, ISKpn23, the phosphotransferase aph3A-VI, and a 941-bp open reading frame (ORF) that codified a 313-amino acid protein. This ORF was named bla BKC-1. Brazilian Klebsiella carbapenemase-1 (BKC-1) showed a pI of 6.0 and possessed the highest identity (63%) with a β-lactamase of Sinorhizobium meliloti, an environmental bacterium. Hydrolysis studies demonstrated that purified BKC-1 not only hydrolyzed carbapenems but also penicillins, cephalosporins, and monobactams. However, the carbapenems were less efficiently hydrolyzed due to their very low kcat values (0.0016 to 0.031 s(-1)). In fact, oxacillin was the best substrate for BKC-1 (kcat /Km , 53,522.6 mM(-1) s(-1)). Here, we report a new class A carbapenemase, confirming the diversity and rapid evolution of β-lactamases in K. pneumoniae clinical isolates.
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