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Al-Madboly LA, El-Salam MAA, Bastos JK, Aboukhatwa S, El-Morsi RM. Characterization of GQA as a novel β-lactamase inhibitor of CTX-M-15 and KPC-2 enzymes. Microb Cell Fact 2024; 23:221. [PMID: 39118086 PMCID: PMC11308155 DOI: 10.1186/s12934-024-02421-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/11/2024] [Indexed: 08/10/2024] Open
Abstract
β-lactam resistance is a significant global public health issue. Outbreaks of bacteria resistant to extended-spectrum β-lactams and carbapenems are serious health concerns that not only complicate medical care but also impact patient outcomes. The primary objective of this work was to express and purify two soluble recombinant representative serine β‑lactamases using Escherichia coli strain as an expression host and pET101/D as a cloning vector. Furthermore, a second objective was to evaluate the potential, innovative, and safe use of galloylquinic acid (GQA) from Copaifera lucens as a potential β-lactamase inhibitor.In the present study, blaCTX-M-15 and blaKPC-2 represented genes encoding for serine β-lactamases that were cloned from parent isolates of E. coli and K. pneumoniae, respectively, and expression as well as purification were performed. Moreover, susceptibility results demonstrated that recombinant cells became resistant to all test carbapenems (MICs; 64-128 µg/mL) and cephalosporins (MICs; 128-512 µg/mL). The MICs of the tested β-lactam antibiotics were determined in combination with 4 µg/mL of GQA, clavulanic acid, or tazobactam against E. coli strains expressing CTX-M-15 or KPC-2-β-lactamases. Interestingly, the combination with GQA resulted in an important reduction in the MIC values by 64-512-fold to the susceptible range with comparable results for other reference inhibitors. Additionally, the half-maximal inhibitory concentration of GQA was determined using nitrocefin as a β-lactamase substrate. Data showed that the test agent was similar to tazobactam as an efficient inhibitors of the test enzymes, recording smaller IC50 values (CTX-M-15; 17.51 for tazobactam, 28.16 µg/mL for GQA however, KPC-2; 20.91 for tazobactam, 24.76 µg/mL for GQA) compared to clavulanic acid. Our work introduces GQA as a novel non-β-lactam inhibitor, which interacts with the crucial residues involved in β-lactam recognition and hydrolysis by non-covalent interactions, complementing the enzyme's active site. GQA markedly enhanced the potency of β-lactams against carbapenemase and extended-spectrum β-lactamase-producing strains, reducing the MICs of β-lactams to the susceptible range. The β-lactamase inhibitory activity of GQA makes it a promising lead molecule for the development of more potent β-lactamase inhibitors.
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Affiliation(s)
- Lamiaa A Al-Madboly
- Department of Microbiology and Immunology, Faculty of Pharmacy, Tanta University, Tanta, Egypt.
| | - Mohamed A Abd El-Salam
- Department of Pharmacognosy, Faculty of Pharmacy, Delta University for Science and Technology, International Coastal Road, Gamasa, 11152, Egypt.
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, D02 VN51, Ireland.
| | - Jairo K Bastos
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, São Paulo, SP, 14040-903, Brazil
| | - Shaimaa Aboukhatwa
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, Egypt
| | - Rasha M El-Morsi
- Department of Microbiology and Immunology, Faculty of Pharmacy, Delta University for Science and Technology, International Coastal Road, Gamasa, 11152, Egypt
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Pospišil M, Car H, Elveđi-Gašparović V, Beader N, Herljević Z, Bedenić B. Bloodstream Infections by AmpC-Producing Enterobacterales: Risk Factors and Therapeutic Outcome. Pathogens 2023; 12:1125. [PMID: 37764933 PMCID: PMC10535069 DOI: 10.3390/pathogens12091125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/29/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Bloodstream infections associated with AmpC-producing Enterobacterales are severe medical conditions which, without prompt and effective treatment, may have dire ramifications. This study aimed to assess whether certain comorbidities and previous surgical procedures coincide with resistance determinants of AmpC-producing Enterobacterales associated with bloodstream infections. Antibiotic resistance patterns and therapy outcome were also determined. The patients' data obtained revealed that the prevalence of recent surgical procedures, solid organ tumors, metabolic diseases, kidney and liver failure, and hematological malignancies do not differ between resistant and susceptible isolates of AmpC-producing Enterobacterales. Furthermore, no difference was reported in mortality rates. Regarding antibiotic resistance, 34.52% of isolates were confirmed to be resistant (AmpC hyperproduction, ESBL, or carbapenemase). More than one in five AmpC hyperproducers were reported amid Providencia spp., K. aerogenes, E. cloacae, and C. freundii. strains. Carbapenemases were mostly noted in Providencia spp. followed by M. morganii and K. aerogenes strains. Serratia marcescens had the highest proportion of ESBLsof ESBLs. Resistance to expanded-spectrum cephalosporins of Providencia spp. and K. aerogenes strains exceeded 50%, and resistance to meropenem over 10% was observed only in C. freundii strains. Enterobacterales' ever-growing resistance to antibiotics is becoming quite a challenge for clinicians and new treatment options are required.
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Affiliation(s)
- Mladen Pospišil
- Krapina-Zagorje County Community Health Centre, 49245 Stubica, Croatia;
| | - Haris Car
- Zagreb Health School, 10000 Zagreb, Croatia;
| | - Vesna Elveđi-Gašparović
- Department of Gynecology and Obstetrics, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Department of Gynecology and Obstetrics, University Hospital Centre Zagreb, 10000 Zagreb, Croatia
| | - Nataša Beader
- BIMIS—Biomedical Research Center Šalata, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Clinical Department for Clinical and Molecular Microbiology, University Hospital Centre Zagreb, 10000 Zagreb, Croatia;
| | - Zoran Herljević
- Clinical Department for Clinical and Molecular Microbiology, University Hospital Centre Zagreb, 10000 Zagreb, Croatia;
| | - Branka Bedenić
- BIMIS—Biomedical Research Center Šalata, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia;
- Clinical Department for Clinical and Molecular Microbiology, University Hospital Centre Zagreb, 10000 Zagreb, Croatia;
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Clancy CJ, Nguyen MH. Management of Highly Resistant Gram-Negative Infections in the Intensive Care Unit in the Era of Novel Antibiotics. Infect Dis Clin North Am 2022; 36:791-823. [DOI: 10.1016/j.idc.2022.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hussan JR, Irwin SG, Mathews B, Swift S, Williams DL, Cornish J. Optimal dose of lactoferrin reduces the resilience of in vitro Staphylococcus aureus colonies. PLoS One 2022; 17:e0273088. [PMID: 35960734 PMCID: PMC9374217 DOI: 10.1371/journal.pone.0273088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 08/02/2022] [Indexed: 11/19/2022] Open
Abstract
The rise in antibiotic resistance has stimulated research into adjuvants that can improve the efficacy of broad-spectrum antibiotics. Lactoferrin is a candidate adjuvant; it is a multifunctional iron-binding protein with antimicrobial properties. It is known to show dose-dependent antimicrobial activity against Staphylococcus aureus through iron sequestration and repression of β–lactamase expression. However, S. aureus can extract iron from lactoferrin through siderophores for their growth, which confounds the resolution of lactoferrin’s method of action. We measured the minimum inhibitory concentration (MIC) for a range of lactoferrin/ β–lactam antibiotic dose combinations and observed that at low doses (< 0.39 μM), lactoferrin contributes to increased S. aureus growth, but at higher doses (> 6.25 μM), iron-depleted native lactoferrin reduced bacterial growth and reduced the MIC of the β-lactam-antibiotic cefazolin. This differential behaviour points to a bacterial population response to the lactoferrin/ β–lactam dose combination. Here, with the aid of a mathematical model, we show that lactoferrin stratifies the bacterial population, and the resulting population heterogeneity is at the basis of the dose dependent response seen. Further, lactoferrin disables a sub-population from β-lactam-induced production of β-lactamase, which when sufficiently large reduces the population’s ability to recover after being treated by an antibiotic. Our analysis shows that an optimal dose of lactoferrin acts as a suitable adjuvant to eliminate S. aureus colonies using β-lactams, but sub-inhibitory doses of lactoferrin reduces the efficacy of β-lactams.
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Affiliation(s)
- Jagir R. Hussan
- Auckland Bioengineering Institute, University of Auckland, Auckland, NZ
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, NZ
- * E-mail:
| | - Stuart G. Irwin
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, NZ
| | - Brya Mathews
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, NZ
| | - Simon Swift
- Department of Molecular Medicine and Pathology, University of Auckland, Auckland, NZ
| | - Dustin L. Williams
- Department of Microbiology and Immunology, School of Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Jillian Cornish
- Department of Medicine, University of Auckland, Auckland, NZ
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Mallik D, Jain D, Bhakta S, Ghosh AS. Role of AmpC-Inducing Genes in Modulating Other Serine Beta-Lactamases in Escherichia coli. Antibiotics (Basel) 2022; 11:antibiotics11010067. [PMID: 35052944 PMCID: PMC8772759 DOI: 10.3390/antibiotics11010067] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/21/2021] [Accepted: 01/05/2022] [Indexed: 02/04/2023] Open
Abstract
The consistently mutating bacterial genotypes appear to have accelerated the global challenge with antimicrobial resistance (AMR); it is therefore timely to investigate certain less-explored fields of targeting AMR mechanisms in bacterial pathogens. One of such areas is beta-lactamase (BLA) induction that can provide us with a collection of prospective therapeutic targets. The key genes (ampD, ampE and ampG) to which the AmpC induction mechanism is linked are also involved in regulating the production of fragmented muropeptides generated during cell-wall peptidoglycan recycling. Although the involvement of these genes in inducing class C BLAs is apparent, their effect on serine beta-lactamase (serine-BLA) induction is little known. Here, by using ∆ampD and ∆ampE mutants of E. coli, we attempted to elucidate the effects of ampD and ampE on the expression of serine-BLAs originating from Enterobacteriaceae, viz., CTX-M-15, TEM-1 and OXA-2. Results show that cefotaxime is the preferred inducer for CTX-M-15 and amoxicillin for TEM-1, whereas oxacillin for OXA-2. Surprisingly, exogenous BLA expressions are elevated in ∆ampD and ∆ampE mutants but do not always alter their beta-lactam susceptibility. Moreover, the beta-lactam resistance is increased upon in trans expression of ampD, whereas the same is decreased upon ampE expression, indicating a differential effect of ampD and ampE overexpression. In a nutshell, depending on the BLA, AmpD amidase moderately facilitates a varying level of serine-BLA expression whereas AmpE transporter acts likely as a negative regulator of serine-BLA.
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Affiliation(s)
- Dhriti Mallik
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
| | - Diamond Jain
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
| | - Sanjib Bhakta
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK;
| | - Anindya Sundar Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India; (D.M.); (D.J.)
- Correspondence:
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Tamma PD, Aitken SL, Bonomo RA, Mathers AJ, van Duin D, Clancy CJ. Infectious Diseases Society of America Guidance on the Treatment of AmpC β-lactamase-Producing Enterobacterales, Carbapenem-Resistant Acinetobacter baumannii, and Stenotrophomonas maltophilia Infections. Clin Infect Dis 2021; 74:2089-2114. [PMID: 34864936 DOI: 10.1093/cid/ciab1013] [Citation(s) in RCA: 250] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The Infectious Diseases Society of America (IDSA) is committed to providing up-to-date guidance on the treatment of antimicrobial-resistant infections. A previous guidance document focused on infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with difficult-to-treat resistance (DTR-P. aeruginosa). Here, guidance is provided for treating AmpC β-lactamase-producing Enterobacterales (AmpC-E), carbapenem-resistant Acinetobacter baumannii (CRAB), and Stenotrophomonas maltophilia infections. METHODS A panel of six infectious diseases specialists with expertise in managing antimicrobial-resistant infections formulated questions about the treatment of AmpC-E, CRAB, and S. maltophilia infections. Answers are presented as suggestions and corresponding rationales. In contrast to guidance in the previous document, published data on optimal treatment of AmpC-E, CRAB, and S. maltophilia infections are limited. As such, guidance in this document is provided as "suggested approaches" based on clinical experience, expert opinion, and a review of the available literature. Because of differences in the epidemiology of resistance and availability of specific anti-infectives internationally, this document focuses on the treatment of infections in the United States. RESULTS Preferred and alternative treatment suggestions are provided, assuming the causative organism has been identified and antibiotic susceptibility results are known. Approaches to empiric treatment, duration of therapy, and other management considerations are also discussed briefly. Suggestions apply for both adult and pediatric populations. CONCLUSIONS The field of antimicrobial resistance is highly dynamic. Consultation with an infectious diseases specialist is recommended for the treatment of antimicrobial-resistant infections. This document is current as of September 17, 2021 and will be updated annually. The most current versions of IDSA documents, including dates of publication, are available at www.idsociety.org/practice-guideline/amr-guidance-2.0/.
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Affiliation(s)
- Pranita D Tamma
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Samuel L Aitken
- Department of Pharmacy, University of Michigan Health, Ann Arbor, Michigan, USA
| | - Robert A Bonomo
- Medical Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, University Hospitals Cleveland Medical Center and Departments of Medicine, Pharmacology, Molecular Biology, and Microbiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Amy J Mathers
- Departments of Medicine and Pathology, University of Virginia, Charlottesville, Virginia, USA
| | - David van Duin
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Cornelius J Clancy
- Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Tamma PD, Doi Y, Bonomo RA, Johnson JK, Simner PJ. A Primer on AmpC β-Lactamases: Necessary Knowledge for an Increasingly Multidrug-resistant World. Clin Infect Dis 2020; 69:1446-1455. [PMID: 30838380 DOI: 10.1093/cid/ciz173] [Citation(s) in RCA: 132] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 02/26/2019] [Indexed: 12/13/2022] Open
Abstract
Understanding the nuances of AmpC β-lactamase-mediated resistance can be challenging, even for the infectious diseases specialist. AmpC resistance can be classified into 3 categories: (1) inducible chromosomal resistance that emerges in the setting of a β-lactam compound, (2) stable derepression due to mutations in ampC regulatory genes, or (3) the presence of plasmid-mediated ampC genes. This review will mainly focus on inducible AmpC resistance in Enterobacteriaceae. Although several observational studies have explored optimal treatment for AmpC producers, few provide reliable insights into effective management approaches. Heterogeneity within the data and inherent selection bias make inferences on effective β-lactam choices problematic. Most experts agree it is prudent to avoid expanded-spectrum (ie, third-generation) cephalosporins for the treatment of organisms posing the greatest risk of ampC induction, which has best been described in the context of Enterobacter cloacae infections. The role of other broad-spectrum β-lactams and the likelihood of ampC induction by other Enterobacteriaceae are less clear. We will review the mechanisms of resistance and triggers resulting in AmpC expression, the species-specific epidemiology of AmpC production, approaches to the detection of AmpC production, and treatment options for AmpC-producing infections.
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Affiliation(s)
- Pranita D Tamma
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yohei Doi
- Department of Medicine, University of Pittsburgh, School of Medicine, Pennsylvania
| | - Robert A Bonomo
- Department of Medicine, The Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Ohio
| | - J Kristie Johnson
- Department of Pathology, University of Maryland School of Medicine, Baltimore
| | - Patricia J Simner
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Welker M, van Belkum A. One System for All: Is Mass Spectrometry a Future Alternative for Conventional Antibiotic Susceptibility Testing? Front Microbiol 2019; 10:2711. [PMID: 31849870 PMCID: PMC6901965 DOI: 10.3389/fmicb.2019.02711] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/08/2019] [Indexed: 12/20/2022] Open
Abstract
The two main pillars of clinical microbiological diagnostics are the identification of potentially pathogenic microorganisms from patient samples and the testing for antibiotic susceptibility (AST) to allow efficient treatment with active antimicrobial agents. While routine microbial species identification is increasingly performed with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), routine AST still largely relies on conventional and molecular techniques such as broth microdilution or disk and gradient diffusion tests, PCR and automated variants thereof. However, shortly after the introduction of MALDI-TOF MS based routine identification, first attempts to perform AST on the same instruments were reported. Today, a number of different approaches to perform AST with MALDI-TOF MS and other MS techniques have been proposed, some restricted to particular microbial taxa and resistance mechanisms while others being more generic. Further, while some of the methods are in a stage of proof of principles, others are already commercialized. In this review we discuss the different principal approaches of mass spectrometry based AST and evaluate the advantages and disadvantages compared to conventional and molecular techniques. At present, the possibility that MS will soon become a routine tool for AST seems unlikely – still, the same was true for routine microbial identification a mere 15 years ago.
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Affiliation(s)
- Martin Welker
- Microbiology Research Unit, BioMérieux SA, La Balme-les-Grottes, France
| | - Alex van Belkum
- Microbiology Research Unit, BioMérieux SA, La Balme-les-Grottes, France
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Abstract
CFE-1 is a unique plasmid-encoded AmpC β-lactamase with the regulator gene ampR. It imparts high resistance to most cephalosporins with constitutive high-level β-lactamase activity. CFE-1 is a unique plasmid-encoded AmpC β-lactamase with the regulator gene ampR. It imparts high resistance to most cephalosporins with constitutive high-level β-lactamase activity. Here, the β-lactamase activities and expression levels of ampC with or without ampR were investigated. Results suggested that the resistance of CFE-1 to cephalosporins is caused by a substitution in AmpR, in which the Asp at position 135 is modified to Ala to allow the constitutive high-level expression (derepression) of ampC.
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Search for non-lactam inhibitors of mtb β-lactamase led to its open shape in apo state: new concept for antibiotic design. Sci Rep 2017; 7:6204. [PMID: 28740144 PMCID: PMC5524718 DOI: 10.1038/s41598-017-06023-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 06/06/2017] [Indexed: 01/14/2023] Open
Abstract
Mtb β-lactamase (BlaC) is extremely efficient in hydrolyzing ß-lactam antibiotics which renders/leads to protection and/or resistance to this bug. There is a compelling need to develop new non-lactam inhibitors which can bind and inhibit BlaC, but cannot be hydrolyzed, thus neutralizing this survival mechanism of Mtb. Using the crystal structure of BlaC we screened 750000 purchasable compounds from ZINC Database for their theoretical affinity to the enzyme’s active site. 32 of the best hits of the compounds having tetra-, tri- and thiadi-azole moiety were tested in vitro, and 4 efficiently inhibited the enzymatic activity of recombinant BlaC. Characterization of the shape of BlaC−/+ inhibitors by small angle X-ray scattering (SAXS) brought forth that BlaC adopts: (1) an open shape (radius of gyration of 2.3 nm compared to 1.9 nm of crystal structures) in solution; (2) closed shape similar to observed crystal structure(s) in presence of effective inhibitor; and (3) a closed shape which opens up when a hydrolysable inhibitor is present in solution. New BlaC inhibitors were: 1-(4-(pyridin-3-yl)-thiazol-2-ylamino)-2-(7,8,9-triaza-bicyclo[4.3.0]nona-1(6),2,4,8-tetraen-7-yl)-ethanone; 8-butyl-3-((5-(pyridin-2-yl)-4H-1,2,4-triazol-3-ylamino)-formyl)-8-aza-bicyclo[4.3.0]nona-1(6),2,4-triene-7,9-dione; 1-(3-((5-(5-bromo-thiophen-2-yl)-1,3,4-oxadiazol-2-yl)-methoxy)-phenyl)-1H-1,2,3,4-tetraazole; and 1-(2,3-dimethyl-phenylamino)-2-(2-(1-(2-methoxy-5-methyl-phenyl)-1H-1,2,3,4-tetraazol-5-ylsulfanyl)-acetylamino)-ethanone. The open-close shape of BlaC questions the physiological significance of the closed shape known for BlaC−/+ inhibitors and paves new path for structure aided design of novel inhibitors.
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Piperacillin-Tazobactam versus Other Antibacterial Agents for Treatment of Bloodstream Infections Due to AmpC β-Lactamase-Producing Enterobacteriaceae. Antimicrob Agents Chemother 2017; 61:AAC.00276-17. [PMID: 28320724 DOI: 10.1128/aac.00276-17] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/15/2017] [Indexed: 01/19/2023] Open
Abstract
In vivo induction of AmpC beta-lactamases produces high-level resistance to many beta-lactam antibiotics in Enterobacteriaceae, often resulting in the need to use carbapenems or cefepime (FEP). The clinical effectiveness of piperacillin-tazobactam (TZP), a weak inducer of AmpC beta-lactamases, is poorly understood. Here, we conducted a case-control study of adult inpatients with bloodstream infections (BSIs) due to Enterobacter, Serratia, or Citrobacter species from 2009 to 2015 to assess outcomes following treatment with TZP compared to FEP or meropenem (MEM). We collected clinical data and screened all isolates for the presence of ampC alleles by PCR. Primary study outcomes were 30-day mortality and persistent bacteremia at ≥72 h from the time of treatment initiation. Of 493 patients with bacteremia, 165 patients met the inclusion criteria, of which 88 were treated with TZP and 77 with FEP or MEM. To minimize differences between covariates, we carried out propensity score matching, which yielded 41 matched pairs. Groups only differed by age, with patients in the TZP group significantly older (P = 0.012). There were no significant differences in 30-day mortality, persistent bacteremia, 7-day mortality, or treatment escalation between the two treatment groups, including in the propensity score-matched cohort. PCR amplification and sequencing of ampC genes revealed the presence of ampC in isolates with cefoxitin MICs below 16 μg/ml, in particular in Serratia spp., and demonstrated that these alleles were highly genetically diverse. Taken together, TZP may be a valuable treatment option for BSIs due to AmpC beta-lactamase-producing Enterobacteriaceae, diminishing the need for broader-spectrum agents. Future studies are needed to validate these findings.
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Hsieh WS, Wang NY, Feng JA, Weng LC, Wu HH. Identification of DHA-23, a novel plasmid-mediated and inducible AmpC beta-lactamase from Enterobacteriaceae in Northern Taiwan. Front Microbiol 2015; 6:436. [PMID: 25999942 PMCID: PMC4422083 DOI: 10.3389/fmicb.2015.00436] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/22/2015] [Indexed: 12/04/2022] Open
Abstract
Objectives: AmpC β-lactamases are classified as Amber Class C and Bush Group 1. AmpC β-lactamases can hydrolyze broad and extended-spectrum cephalosporins, and are not inhibited by β-lactamase inhibitors such as clavulanic acid. This study was conducted to identify DHA-23, a novel plasmid-mediated and inducible AmpC β-lactamase obtained from Enterobacteriaceae. Methods: A total of 210 carbapenem-resistant Enterobacteriaceae isolates were collected from a medical center (comprising two branches) in Northern Taiwan during 2009–2012. AmpC β-lactamase genes were analyzed through a polymerase chain reaction using plasmid DNA templates and gene sequencing. The genetic relationships of the isolates were typed using pulsed-field gel electrophoresis following the digestion of intact genomic DNA by using XbaI. Results: Three enterobacterial isolates (one Escherichia coli and two Klebsiella pneumoniae) were obtained from three hospitalized patients. All three isolates were resistant or intermediately susceptible to all β-lactams, and exhibited reduced susceptibility to carbapenems. These three isolates expressed a novel AmpC β-lactamase, designated DHA-23, approved by the curators of the Lahey website. DHA-23 differs from DHA-1 and DHA-6 by one amino acid substitution (Ser245Ala), exhibiting three amino acid changes compared with DHA-7 and DHA-Morganella morganii; three amino acid changes compared with DHA-3; four amino acid changes compared with DHA-5; and eight amino acid changes compared with DHA-2 (>97% identity). This AmpC β-lactamase is inducible using a system involving ampR. Conclusion: This is the first report to address DHA-23, a novel AmpC β-lactamase. DHA-type β-lactamases are continuous threat in Taiwan.
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Affiliation(s)
- Wen-Shyang Hsieh
- Department of Laboratory Medicine, Taipei Medical University - Shuang Ho Hospital, New Taipei City Taiwan ; School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei Taiwan ; Graduate Institute of Biomedical Informatics, Taipei Medical University, Taipei Taiwan
| | - Nai-Yu Wang
- Department of Medical Research, Mackay Memorial Hospital, New Taipei City Taiwan
| | - Jou-An Feng
- Department of Medical Research, Mackay Memorial Hospital, New Taipei City Taiwan
| | - Li-Chuan Weng
- Department of Medical Research, Mackay Memorial Hospital, New Taipei City Taiwan
| | - Hsueh-Hsia Wu
- School of Medical Laboratory Science and Biotechnology, Taipei Medical University, Taipei Taiwan ; Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei Taiwan
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Huang Y, Shan XF, Deng H, Huang YJ, Mu XP, Huang AL, Long QX. Epidemiology, Antimicrobial Resistance and β-lactamase Genotypic Features of Enteropathogenic Escherichia coli Isolated from Children with Diarrhea in Southern China. Jpn J Infect Dis 2015; 68:239-43. [PMID: 25672408 DOI: 10.7883/yoken.jjid.2014.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The main objective of this study was to investigate the epidemiology, drug resistance and β-lactamase genotype distribution of enteropathogenic Escherichia coli (EPEC) isolated from pediatric patients with diarrhea in southern China. The prevalence of EPEC in children with diarrhea was 3.53%. The commonest serotypes were O55:K59 and O126:K71, and the typical EPEC were more prevalent than atypical EPEC (51 vs 7). Isolates from this region were most commonly found to be resistant to ampicillin and cotrimoxazole, followed by chloramphenicol, ceftriaxone, and ceftazidime. More than 96% of the strains were susceptible to cefoperazone/sulbactam and imipenem. The most common β-lactamase genotypes identified in 58 strains were blaCTX-M-1 (60.3%), blaTEM (56.9%), blaCTX-M-9 (27.6%), and blaSHV (15.5%). Among 58 isolates, 22 strains were found to harbor one β-lactamase gene, and the proportions of resistance to ampicillin, cotrimoxazole, chloramphenicol, ceftriaxone, and ceftazidime, were 81.8%, 63.6%, 40.9%, 18.2%, and 9.1%, respectively. A further 30 strains carrying multiple β-lactamase genes had increased resistance to the above antimicrobial agents (100%, 83.3%, 70.0%, 60.0%, and 30.0%, respectively). In contrast, antibiotic resistance in the last 6 strains without a detectable β-lactamase gene was substantially reduced. Drug resistance may be associated with the β-lactamase gene number, with a greater the number of β-lactamase genes resulting in higher antibiotic resistance.
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Affiliation(s)
- Yong Huang
- Key Laboratory of Molecular Biology on Infectious Diseases, Ministry of Education, Second Affiliated Hospital, Chongqing Medical University
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14
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Tondi D, Venturelli A, Bonnet R, Pozzi C, Shoichet BK, Costi MP. Targeting class A and C serine β-lactamases with a broad-spectrum boronic acid derivative. J Med Chem 2014; 57:5449-58. [PMID: 24882105 PMCID: PMC4079326 DOI: 10.1021/jm5006572] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Production
of β-lactamases (BLs) is the most widespread resistance
mechanism adopted by bacteria to fight β-lactam antibiotics.
The substrate spectrum of BLs has become increasingly broad, posing
a serious health problem. Thus, there is an urgent need for novel
BL inhibitors. Boronic acid transition-state analogues are able to
reverse the resistance conferred by class A and C BLs. We describe
a boronic acid analogue possessing interesting and potent broad-spectrum
activity vs class A and C serine-based BLs. Starting from benzo(b)thiophene-2-boronic acid (BZBTH2B), a nanomolar non-β-lactam
inhibitor of AmpC that can potentiate the activity of a third-generation
cephalosporin against AmpC-producing resistant bacteria, we designed
a novel broad-spectrum nanomolar inhibitor of class A and C BLs. Structure-based
drug design (SBDD), synthesis, enzymology data, and X-ray crystallography
results are discussed. We clarified the inhibitor binding geometry
responsible for broad-spectrum activity vs serine-active BLs using
double mutant thermodynamic cycle studies.
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Affiliation(s)
- Donatella Tondi
- Department of Pharmaceutical Chemistry, University of California San Francisco , 600 16th Street San Francisco, California 94143-2240, United States
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15
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Abstract
The production of β-lactamase is one of the primary resistance mechanisms used by Gram-negative bacterial pathogens to counter β-lactam antibiotics, such as penicillins, cephalosporins and carbapenems. There is an urgent need to develop novel β-lactamase inhibitors in response to ever evolving β-lactamases possessing an expanded spectrum of β-lactam hydrolyzing activity. Whereas traditional high-throughput screening has proven ineffective against serine β-lactamases, fragment-based approaches have been successfully employed to identify novel chemical matter, which in turn has revealed much about the specific molecular interactions possible in the active site of serine and metallo β-lactamases. In this review, we summarize recent progress in the field, particularly: the identification of novel inhibitor chemotypes through fragment-based screening; the use of fragment-protein structures to understand key features of binding hot spots and inform the design of improved leads; lessons learned and new prospects for β-lactamase inhibitor development using fragment-based approaches.
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Affiliation(s)
- Derek A Nichols
- University of South Florida College of Medicine, Department of Molecular Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, FL 33612, USA
| | - Adam R Renslo
- Department of Pharmaceutical Chemistry & Small Molecule Discovery Center, University of California San Francisco, 1700 4th Street, Byers Hall S504, San Francisco, CA 94158, USA
| | - Yu Chen
- University of South Florida College of Medicine, Department of Molecular Medicine, 12901 Bruce B. Downs Blvd, MDC 3522, Tampa, FL 33612, USA
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16
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Jung JA, Kim A, Seo BJ, Jung SC, Kim IC, Chung KH, Jung BY. Specific Detection of Serratia marcescens Based on a PCR Assay and Antimicrobial Susceptibility of S. marcescens Isolated from Boar Semen. ACTA ACUST UNITED AC 2013. [DOI: 10.5352/jls.2013.23.9.1133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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17
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Biochemical characterization of CTX-M-15 from Enterobacter cloacae and designing a novel non-β-lactam-β-lactamase inhibitor. PLoS One 2013; 8:e56926. [PMID: 23437273 PMCID: PMC3578935 DOI: 10.1371/journal.pone.0056926] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 01/16/2013] [Indexed: 11/19/2022] Open
Abstract
The worldwide dissemination of CTX-M type β-lactamases is a threat to human health. Previously, we have reported the spread of blaCTX-M-15 gene in different clinical strains of Enterobacteriaceae from the hospital settings of Aligarh in north India. In view of the varying resistance pattern against cephalosporins and other β-lactam antibiotics, we intended to understand the correlation between MICs and catalytic activity of CTX-M-15. In this study, steady-state kinetic parameters and MICs were determined on E. coli DH5α transformed with blaCTX-M-15 gene that was cloned from Enterobacter cloacae (EC-15) strain of clinical background. The effect of conventional β-lactamase inhibitors (clavulanic acid, sulbactam and tazobactam) on CTX-M-15 was also studied. We have found that tazobactam is the best among these inhibitors against CTX-M-15. The inhibition characteristic of tazobactam is defined by its very low IC50 value (6 nM), high affinity (Ki = 0.017 µM) and better acylation efficiency (k+2/K′ = 0.44 µM−1s−1). It forms an acyl-enzyme covalent complex, which is quite stable (k+3 = 0.0057 s−1). Since increasing resistance has been reported against conventional β-lactam antibiotic-inhibitor combinations, we aspire to design a non-β-lactam core containing β-lactamase inhibitor. For this, we screened ZINC database and performed molecular docking to identify a potential non-β-lactam based inhibitor (ZINC03787097). The MICs of cephalosporin antibiotics in combination with this inhibitor gave promising results. Steady-state kinetics and molecular docking studies showed that ZINC03787097 is a reversible inhibitor which binds non-covalently to the active site of the enzyme through hydrogen bonds and hydrophobic interactions. Though, it’s IC50 (180 nM) is much higher than tazobactam, it has good affinity for CTX-M-15 (Ki = 0.388 µM). This study concludes that ZINC03787097 compound can be used as seed molecule to design more efficient non-β-lactam containing β-lactamase inhibitor that could evade pre-existing bacterial resistance mechanisms.
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18
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High Prevalence and Significant Association of ESBL and QNR Genes in Pathogenic Klebsiella pneumoniae Isolates of Patients from Kolkata, India. Indian J Microbiol 2012; 52:557-64. [PMID: 24293710 DOI: 10.1007/s12088-012-0281-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Accepted: 06/04/2012] [Indexed: 10/28/2022] Open
Abstract
Pathogenic Klebsiella pneumoniae, resistant to beta-lactam and quinolone drugs, is widely recognized as important bacteria causing array of diseases. The resistance property is obtained by acquisition of plasmid encoded blaTEM, blaSHV, blaCTX-M, QNRA, QNRB and QNRS genes. The aim of this study was to document the prevalence and association of these resistant genes in K. pneumoniae infecting patients in India. Approximately 97 and 76.7 % of the 73 K. pneumoniae isolates showed resistance towards beta-lactam and quinolone drugs respectively. Bla genes were detected in 74 % of K. pneumoniae isolates; with prevalence in the following order: blaTEM > blaSHV > blaCTXM. QNR genes were detected in 67 % samples. Chi-square analysis revealed significant association between presence of bla and qnr genes in our study (P value = 0.000125). Sequence analysis of some blaTEM, blaSHV, blaCTX-M and QNRB PCR products revealed presence of blaTEM1 (GenBank accession: JN193522), blaTEM116 (JN193523 and JN193524), blaSHV11, blaCTXM72 variants (JF523199) and QNRB1 (JN193526 and JN193527) in our samples.
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19
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Phelan RM, DiPardo BJ, Townsend CA. A high-throughput screen for the engineered production of β-lactam antibiotics. ACS Chem Biol 2012; 7:835-40. [PMID: 22428872 DOI: 10.1021/cb200504g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
High-throughput screens and selections have had profound impact on our ability to engineer proteins possessing new, desired properties. These methods are especially useful when applied to the modification of existing enzymes to create natural and unnatural products. In an advance upon existing methods we developed a high-throughput, genetically regulated screen for the in vivo production of β-lactam antibiotics using a green fluorescent protein (gfp) reporter. This assay proved reliable and sensitive and presents a dynamic range under which a wide array of β-lactam architectural subclasses can be detected. Moreover, the graded response elicited in this assay can be used to rank mutant activity. The utility of this development was demonstrated in vivo and then applied to the first experimental investigation of a putative catalytic residue in carbapenem synthase (CarC). Information gained about the mutability of this residue defines one parameter for enzymatic activity and sets boundaries for future mechanistic and engineering efforts.
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Affiliation(s)
- Ryan M. Phelan
- Department
of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland
21218, United States
| | - Benjamin J. DiPardo
- Department
of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland
21218, United States
| | - Craig A. Townsend
- Department
of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland
21218, United States
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20
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Chan FY, Neves MAC, Sun N, Tsang MW, Leung YC, Chan TH, Abagyan R, Wong KY. Validation of the AmpC β-Lactamase Binding Site and Identification of Inhibitors with Novel Scaffolds. J Chem Inf Model 2012; 52:1367-75. [DOI: 10.1021/ci300068m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fung-Yi Chan
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
| | - Marco A. C. Neves
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
- Centro de Neurociências,
Lab. Química Farmacêutica, Faculdade de Farmácia, Universidade de Coimbra, Pólo das Ciências
da Saúde, 3000-548 Coimbra, Portugal
| | - Ning Sun
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
| | - Man-Wah Tsang
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
| | - Yun-Chung Leung
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
| | - Tak-Hang Chan
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
| | - Ruben Abagyan
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Kwok-Yin Wong
- Department
of Applied Biology
and Chemical Technology and State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon,
Hong Kong, P. R. China
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21
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Nichols DA, Jaishankar P, Larson W, Smith E, Liu G, Beyrouthy R, Bonnet R, Renslo AR, Chen Y. Structure-based design of potent and ligand-efficient inhibitors of CTX-M class A β-lactamase. J Med Chem 2012; 55:2163-72. [PMID: 22296601 DOI: 10.1021/jm2014138] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The emergence of CTX-M class A extended-spectrum β-lactamases poses a serious health threat to the public. We have applied structure-based design to improve the potency of a novel noncovalent tetrazole-containing CTX-M inhibitor (K(i) = 21 μM) more than 200-fold via structural modifications targeting two binding hot spots, a hydrophobic shelf formed by Pro167 and a polar site anchored by Asp240. Functional groups contacting each binding hot spot independently in initial designs were later combined to produce analogues with submicromolar potencies, including 6-trifluoromethyl-3H-benzoimidazole-4-carboxylic acid [3-(1H-tetrazol-5-yl)-phenyl]-amide, which had a K(i) value of 89 nM and reduced the MIC of cefotaxime by 64-fold in CTX-M-9 expressing Escherichia coli . The in vitro potency gains were accompanied by improvements in ligand efficiency (from 0.30 to 0.39) and LipE (from 1.37 to 3.86). These new analogues represent the first nM-affinity noncovalent inhibitors of a class A β-lactamase. Their complex crystal structures provide valuable information about ligand binding for future inhibitor design.
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Affiliation(s)
- Derek A Nichols
- University of South Florida College of Medicine, Department of Molecular Medicine, 12901 Bruce B. Downs Boulevard, MDC 3522, Tampa, Florida 33612, USA
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22
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Minozzi M, Lattanzi G, Benz R, Costi MP, Venturelli A, Carloni P. Permeation through the cell membrane of a boron-based β-lactamase inhibitor. PLoS One 2011; 6:e23187. [PMID: 21858024 PMCID: PMC3157353 DOI: 10.1371/journal.pone.0023187] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Accepted: 07/11/2011] [Indexed: 11/19/2022] Open
Abstract
Bacteria express beta-lactamases to counteract the beneficial action of antibiotics. Benzo[b]-thiophene-2-boronic acid (BZB) derivatives are β-lactamase inhibitors and, as such, promising compounds to be associated with β-lactam antibacterial therapies. The uncharged form of BZB, in particular, is suggested to diffuse through the outer membrane of gram negative bacteria. In this study, through the combination of electrophysiological experiments across reconstituted PC/n-decane bilayers and metadynamics-based free energy calculations, we investigate the permeation mechanism of boronic compounds. Our experimental data establish that BZB passes through the membrane, while computer simulations provide hints for the existence of an aqueous, water-filled monomolecular channel. These findings provide new perspectives for the design of boronic acid derivatives with high membrane permeability.
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Affiliation(s)
- Manuela Minozzi
- Modeling & Simulation Lab Department of Studies on Structures, University “Roma Tre”, Roma, Italy
| | - Gianluca Lattanzi
- Department of Basic Medical Sciences, TIRES Centre and Istituto Nazionale di Fisica Nucleare, University of Bari “Aldo Moro”, Bari, Italy
- * E-mail:
| | - Roland Benz
- School of Engineering and Science Jacobs-University Bremen, Bremen, Germany
| | - Maria P. Costi
- University of Modena and Reggio Emilia, Pharmaceutical Sciences Dept., Modena, Italy
| | - Alberto Venturelli
- University of Modena and Reggio Emilia, Pharmaceutical Sciences Dept., Modena, Italy
| | - Paolo Carloni
- German Research School for Simulation Science, Jülich Research Center and RWTH-Aachen University, Jülich, Germany
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23
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MacDougall C. Beyond Susceptible and Resistant, Part I: Treatment of Infections Due to Gram-Negative Organisms With Inducible β-Lactamases. J Pediatr Pharmacol Ther 2011. [DOI: 10.5863/1551-6776-16.1.23] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
ABSTRACT
Inactivation of β-lactams by the action of β-lactamase enzymes is the most common mode of resistance to these drugs among Gram-negative organisms. The genomes of some key clinical pathogens such as Enterobacter and Pseudomonas encode AmpC, an inducible chromosomal β-lactamase. The potent activity of AmpC against broad-spectrum β-lactams complicates treatment of organisms with this gene. Antibiotic exposure can select for mutants expressing high levels of this enzyme, leading to the emergence of resistant isolates and failure of therapy, even when the initial isolate is fully susceptible. The risk of selecting for resistant organisms varies according to the particular β-lactam used for treatment. This article reviews the microbiology of these enzymes, summarizes clinical data on the frequency emergence of resistance, and discusses considerations for antimicrobial treatment of these organisms.
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Affiliation(s)
- Conan MacDougall
- Department of Clinical Pharmacy, University of California, San Francisco School of Pharmacy, San Francisco, California
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24
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MacDougall C. Beyond Susceptible and Resistant, Part I: Treatment of Infections Due to Gram-Negative Organisms With Inducible β-Lactamases. J Pediatr Pharmacol Ther 2011; 16:23-30. [PMID: 22477821 PMCID: PMC3136230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Inactivation of β-lactams by the action of β-lactamase enzymes is the most common mode of resistance to these drugs among Gram-negative organisms. The genomes of some key clinical pathogens such as Enterobacter and Pseudomonas encode AmpC, an inducible chromosomal β-lactamase. The potent activity of AmpC against broad-spectrum β-lactams complicates treatment of organisms with this gene. Antibiotic exposure can select for mutants expressing high levels of this enzyme, leading to the emergence of resistant isolates and failure of therapy, even when the initial isolate is fully susceptible. The risk of selecting for resistant organisms varies according to the particular β-lactam used for treatment. This article reviews the microbiology of these enzymes, summarizes clinical data on the frequency emergence of resistance, and discusses considerations for antimicrobial treatment of these organisms.
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Affiliation(s)
- Conan MacDougall
- Department of Clinical Pharmacy, University of California, San Francisco School of Pharmacy, San Francisco, California
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25
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Abstract
Since the introduction of penicillin, beta-lactam antibiotics have been the antimicrobial agents of choice. Unfortunately, the efficacy of these life-saving antibiotics is significantly threatened by bacterial beta-lactamases. beta-Lactamases are now responsible for resistance to penicillins, extended-spectrum cephalosporins, monobactams, and carbapenems. In order to overcome beta-lactamase-mediated resistance, beta-lactamase inhibitors (clavulanate, sulbactam, and tazobactam) were introduced into clinical practice. These inhibitors greatly enhance the efficacy of their partner beta-lactams (amoxicillin, ampicillin, piperacillin, and ticarcillin) in the treatment of serious Enterobacteriaceae and penicillin-resistant staphylococcal infections. However, selective pressure from excess antibiotic use accelerated the emergence of resistance to beta-lactam-beta-lactamase inhibitor combinations. Furthermore, the prevalence of clinically relevant beta-lactamases from other classes that are resistant to inhibition is rapidly increasing. There is an urgent need for effective inhibitors that can restore the activity of beta-lactams. Here, we review the catalytic mechanisms of each beta-lactamase class. We then discuss approaches for circumventing beta-lactamase-mediated resistance, including properties and characteristics of mechanism-based inactivators. We next highlight the mechanisms of action and salient clinical and microbiological features of beta-lactamase inhibitors. We also emphasize their therapeutic applications. We close by focusing on novel compounds and the chemical features of these agents that may contribute to a "second generation" of inhibitors. The goal for the next 3 decades will be to design inhibitors that will be effective for more than a single class of beta-lactamases.
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Affiliation(s)
- Sarah M. Drawz
- Departments of Pathology, Medicine, Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
| | - Robert A. Bonomo
- Departments of Pathology, Medicine, Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio
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26
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27
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Coleman K. Section Review: Anti-infectives: An update on β-lactamases and β-lactamase inhibitors. Expert Opin Investig Drugs 2008. [DOI: 10.1517/13543784.4.8.693] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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28
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Burchard GD, Einsele H, Hebart H, Heinz WJ, Herrmann M, Hörauf A, Mertens T, von Müller L, Zimmerli W. Antimikrobielle Therapie. KLINISCHE INFEKTIOLOGIE 2008. [PMCID: PMC7158361 DOI: 10.1016/b978-343721741-8.50008-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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29
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Venturelli A, Tondi D, Cancian L, Morandi F, Cannazza G, Segatore B, Prati F, Amicosante G, Shoichet BK, Costi MP. Optimizing cell permeation of an antibiotic resistance inhibitor for improved efficacy. J Med Chem 2007; 50:5644-54. [PMID: 17956081 DOI: 10.1021/jm070643q] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benzo[b]thiophene-2-ylboronic acid, 1, is a 27 nM inhibitor of the class C beta-lactamase AmpC and potentiates the activity of beta-lactam antibiotics in bacteria that express this and related enzymes. As is often true, the potency of compound 1 against the enzymes is much attenuated in cell culture against Gram negative bacteria, where the minimum inhibitor concentration of compound 1 is in the mid-micromolar range. Here, we modulated the properties of this lead to enhance its ability to cross the membrane, using a combination of X-ray crystallography, structure-based design, and application of physical models of outer membrane crossing. This strategy led us to derivatives with substantially improved permeability. Also, the greater solubility of these compounds allowed us to measure their efficacy at higher concentrations than with the lead 1, leading to higher maximum potentiation of the antibiotic effect of ceftazidime on resistant bacteria.
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Affiliation(s)
- Alberto Venturelli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100, Modena, Italy
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30
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Li XZ, Mehrotra M, Ghimire S, Adewoye L. beta-Lactam resistance and beta-lactamases in bacteria of animal origin. Vet Microbiol 2007; 121:197-214. [PMID: 17306475 DOI: 10.1016/j.vetmic.2007.01.015] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 12/18/2006] [Accepted: 01/15/2007] [Indexed: 11/30/2022]
Abstract
beta-Lactams are among the most clinically important antimicrobials in both human and veterinary medicine. Bacterial resistance to beta-lactams has been increasingly observed in bacteria, including those of animal origin. The mechanisms of beta-lactam resistance include inaccessibility of the drugs to their target, target alterations and/or inactivation of the drugs by beta-lactamases. The latter contributes predominantly to beta-lactam resistance in Gram-negative bacteria. A variety of beta-lactamases have been identified in bacteria derived from food-producing and companion animals and may further serve as a reservoir for beta-lactamase-producing bacteria in humans. While this review mainly describes beta-lactamases from animal-derived Escherichia coli and Salmonella spp., beta-lactamases from animal-derived Campylobacter spp., Enterococcus spp., Staphylococcus spp. and other pathogens are also discussed. Of particular concern are the increasingly-isolated plasmid-encoded AmpC-type CMY and extended-spectrum CTX-M beta-lactamases, which mediate acquired resistance to extended-spectrum beta-lactams. The genes encoding these enzymes often coexist with other antimicrobial resistance determinants and can also be associated with transposons/integrons, increasing the potential enrichment of multidrug resistant bacteria by multiple antimicrobial agents as well as dissemination of the resistance determinants among bacterial species. Characterization of beta-lactam-resistant animal-derived bacteria warrants further investigation of the type and distribution of beta-lactamases in bacteria of animal origin and their potential impact on human medicine.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, 14-11 Holland Avenue, Ottawa, Ontario K1A OK9, Canada.
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31
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Girlich D, Naas T, Nordmann P. Regulation of class D beta-lactamase gene expression in Ralstonia pickettii. MICROBIOLOGY-SGM 2006; 152:2661-2672. [PMID: 16946261 DOI: 10.1099/mic.0.29027-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ralstonia pickettii, an environmental bacterium that may also be responsible for human infections, produces two unrelated, inducible and chromosomally encoded oxacillinases, OXA-22 and OXA-60. In order to study the molecular basis of the induction process of these oxacillinase genes, the induction kinetics, the promoter/operator regions necessary for expression and induction, and the role of several ORFs located upstream and downstream of the bla(OXA) genes were investigated. The beta-lactamase production reached a maximal level after 1 h induction, returned to its basal level within the following 3 h and was then again inducible. Using 5'RACE experiments, the promoter sequences of both oxacillinases were determined. These sequences showed weak promoter activities, which could, however, be increased approximately 200-fold by mutating the -35 promoter sequence. Deletion of the sequences located upstream of the promoter regions did not modify the basal beta-lactamase expression in R. pickettii, but resulted in the lack of induction. A minimum of 240 and 270 bp upstream of the transcription initiation sites was required for inducible expression of the bla(OXA-22) and bla(OXA-60) genes, respectively. Analysis of the genetic environment of both bla(OXA) genes revealed several ORFs that were inactivated by homologous recombination. Disruption of ORF-RP3, located 190 bp upstream of bla(OXA-60) and divergently transcribed, abolished induction of both beta-lactamases. ORF-RP3, which encoded a polypeptide of 532 aa with an estimated molecular mass of 58.7 kDa, displayed no obvious sequence homology with known regulatory proteins. Trans-complementation of ORF-RP3 restored the basal and inducible expression of both oxacillinase genes, indicating that the induction of both enzymes was related to the presence of ORF-RP3. In addition to the loss of induction, inactivation of the ORF-RP3 in R. pickettii resulted in a complex pleiotropic phenotype, with increased lag phase and reduced survival after heat exposure, suggesting that ORF-RP3 might be a global regulator involved in unrelated regulatory pathways.
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Affiliation(s)
- Delphine Girlich
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris XI, 94275 Le Kremlin-Bicêtre, France
| | - Thierry Naas
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris XI, 94275 Le Kremlin-Bicêtre, France
| | - Patrice Nordmann
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, Université Paris XI, 94275 Le Kremlin-Bicêtre, France
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Bina XR, Wang C, Miller MA, Bina JE. The Bla2 beta-lactamase from the live-vaccine strain of Francisella tularensis encodes a functional protein that is only active against penicillin-class beta-lactam antibiotics. Arch Microbiol 2006; 186:219-28. [PMID: 16841206 DOI: 10.1007/s00203-006-0140-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 05/09/2006] [Accepted: 06/19/2006] [Indexed: 10/24/2022]
Abstract
Francisella tularensis ssp. tularensis is a category A select agent and the causal organism for the zoonotic disease tularemia. The vast majority of F. tularensis isolates are beta-lactamase-positive. beta-lactamase production is widely believed to be responsible for the inefficacy of beta-lactams in the treatment of tularemia. In this study, we report the cloning and characterization of the two chromosomally encoded F. tularensis ssp. holarctica live-vaccine strain (LVS) beta-lactamases. The two LVS beta-lactamases were homologous to F. tularensis Schu S4 open reading frames FTT0681c and FTT0611c and have been named bla1 (LVS) and bla2 (LVS), respectively. Recombinant expression in Escherichia coli suggested that bla1 (LVS) did not encode a functional beta-lactamase, whereas bla2 (LVS) encoded a functional beta-lactamase that hydrolyzed penicillins but was inactive against third-generation cephalosporins, including cefprozil. As both LVS and Schu S4 were susceptible to cefprozil, we developed three new shuttle vectors based on selection for the production of the Bla(shv-2) extended-spectrum beta-lactamase with cefprozil. The resulting shuttle vectors were suitable for recombinant gene expression and complementation studies in LVS and Schu S4.
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Affiliation(s)
- Xiaowen R Bina
- Department of Molecular Sciences, University of Tennessee Health Science Center, 858 Madison Avenue, Memphis, TN 38163, USA
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33
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González-López JJ, Sabaté M, Lavilla S, Larrosa MN, Bartolomé RM, Prats G. In vivo reversion to the wild-type beta-lactam resistance phenotype mediated by a plasmid carrying ampR and qnrA1 in Enterobacter cloacae. Antimicrob Agents Chemother 2006; 50:3175-8. [PMID: 16940123 PMCID: PMC1563562 DOI: 10.1128/aac.00273-06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance to beta-lactams and quinolones in two isogenic Enterobacter cloacae isolates was studied. One was susceptible to cefoxitin and amoxicillin-clavulanate. The other one showed its natural beta-lactam resistance pattern. Both isolates had a nonfunctional AmpR regulator. However, within the second one, the presence of a plasmid carrying ampR and qnrA1 allowed reversion to the wild-type beta-lactam resistance phenotype and decreased susceptibility to fluoroquinolones.
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Affiliation(s)
- J J González-López
- Servicio de Microbiología, Hospital Vall d'Hebron, Universitat Autònoma de Barcelona, Spain
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34
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Lau SKP, Ho PL, Li MWS, Tsoi HW, Yung RWH, Woo PCY, Yuen KY. Cloning and characterization of a chromosomal class C beta-lactamase and its regulatory gene in Laribacter hongkongensis. Antimicrob Agents Chemother 2005; 49:1957-64. [PMID: 15855519 PMCID: PMC1087626 DOI: 10.1128/aac.49.5.1957-1964.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Laribacter hongkongensis, a newly discovered bacterium recently shown to be associated with community-acquired gastroenteritis, is generally resistant to most beta-lactams except the carbapenems. We describe the cloning and characterization of a novel chromosomal class C beta-lactamase and its regulatory gene in L. hongkongensis. Two genes, ampC and ampR, were cloned by inserting restriction fragments of genomic DNA from L. hongkongensis strain HLHK5 into pBK-CMV to give the recombinant plasmid pBK-LHK-5. The ampR and ampC genes and their promoters were divergently oriented, with the ampR gene immediately upstream of the ampC gene and an intercistronic Lys-R motif, typical of inducible ampC-ampR regulatory systems. The deduced amino acid sequence of the cloned AmpC beta-lactamase (pI 8.1) contained consensus motifs characteristic of class C beta-lactamases but had identities no greater than 46% to known class C beta-lactamases. The kinetic properties of this AmpC were also compatible with those of a class C beta-lactamase. PCR of 20 clinical isolates of L. hongkongensis, including HLHK5, showed the presence of both ampC and ampR genes in all isolates. Southern hybridization suggested that the ampC gene of HLHK5 was chromosomally encoded. Subcloning experiments showed that the expression of the ampC gene of HLHK5 was regulated by its ampR gene, which acts as a repressor. The beta-lactamase characterized from strain HLHK5 was named LHK-5 (gene, bla(LHK-5)) and represents the first example of AmpC beta-lactamase in the beta subdivision of proteobacteria.
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Affiliation(s)
- Susanna K P Lau
- Department of Microbiology, The University of Hong Kong, Hong Kong
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Tondi D, Morandi F, Bonnet R, Costi MP, Shoichet BK. Structure-based optimization of a non-beta-lactam lead results in inhibitors that do not up-regulate beta-lactamase expression in cell culture. J Am Chem Soc 2005; 127:4632-9. [PMID: 15796528 PMCID: PMC1360654 DOI: 10.1021/ja042984o] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterial expression of beta-lactamases is the most widespread resistance mechanism to beta-lactam antibiotics, such as penicillins and cephalosporins. There is a pressing need for novel, non-beta-lactam inhibitors of these enzymes. One previously discovered novel inhibitor of the beta-lactamase AmpC, compound 1, has several favorable properties: it is chemically dissimilar to beta-lactams and is a noncovalent, competitive inhibitor of the enzyme. However, at 26 microM its activity is modest. Using the X-ray structure of the AmpC/1 complex as a template, 14 analogues were designed and synthesized. The most active of these, compound 10, had a K(i) of 1 microM, 26-fold better than the lead. To understand the origins of this improved activity, the structures of AmpC in complex with compound 10 and an analogue, compound 11, were determined by X-ray crystallography to 1.97 and 1.96 A, respectively. Compound 10 was active in cell culture, reversing resistance to the third generation cephalosporin ceftazidime in bacterial pathogens expressing AmpC. In contrast to beta-lactam-based inhibitors clavulanate and cefoxitin, compound 10 did not up-regulate beta-lactamase expression in cell culture but simply inhibited the enzyme expressed by the resistant bacteria. Its escape from this resistance mechanism derives from its dissimilarity to beta-lactam antibiotics.
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Affiliation(s)
- Donatella Tondi
- Department of Pharmaceutical Chemistry, University of California-San Francisco, 600 16th Street, San Francisco, CA 94143-2240, USA
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Phillips OA, Reddy AVN, Setti EL, Spevak P, Czajkowski DP, Atwal H, Salama S, Micetich RG, Maiti SN. Synthesis and biological evaluation of penam sulfones as inhibitors of β-lactamases. Bioorg Med Chem 2005; 13:2847-58. [PMID: 15781395 DOI: 10.1016/j.bmc.2005.02.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Revised: 02/10/2005] [Accepted: 02/10/2005] [Indexed: 11/25/2022]
Abstract
The chemical synthesis of a series of new penam sulfone derivatives bearing a 2beta-substituted-oxyimino and -hydrazone substituents, their beta-lactamase inhibitory properties against selected enzymes representing class A and C beta-lactamases are reported. The oxime containing penam sulfones strongly inhibited the Escherichia coli TEM-1 and Klebsiella pneumoniae cefotaximase (CTX-1) enzymes, but moderately inhibited the Pseudomonas aeruginosa 46012 cephalosporinase; while the 2beta-substituted-hydrazone derivatives were generally less active against these enzymes. Furthermore, most of the inhibitors enhanced the antibacterial activities of piperacillin (PIP) and ceftazidime (CAZ) particularly against TEM-1 and CTX-1 producing bacterial strains.
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Affiliation(s)
- Oludotun A Phillips
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kuwait University, PO Box 24923, Safat 13110, Kuwait.
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38
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Nakano R, Okamoto R, Nakano Y, Kaneko K, Okitsu N, Hosaka Y, Inoue M. CFE-1, a novel plasmid-encoded AmpC beta-lactamase with an ampR gene originating from Citrobacter freundii. Antimicrob Agents Chemother 2004; 48:1151-8. [PMID: 15047515 PMCID: PMC375250 DOI: 10.1128/aac.48.4.1151-1158.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A clinical isolate of Escherichia coli from a patient in Japan, isolate KU6400, was found to produce a plasmid-encoded beta-lactamase that conferred resistance to extended-spectrum cephalosporins and cephamycins. Resistance arising from production of a beta-lactamase could be transferred by either conjugation or transformation with plasmid pKU601 into E. coli ML4947. The substrate and inhibition profiles of this enzyme resembled those of the AmpC beta-lactamase. The resistance gene of pKU601, which was cloned and expressed in E. coli, proved to contain an open reading frame showing 99.8% DNA sequence identity with the ampC gene of Citrobacter freundii GC3. DNA sequence analysis also identified a gene upstream of ampC whose sequence was 99.0% identical to the ampR gene from C. freundii GC3. In addition, a fumarate operon (frdABCD) and an outer membrane lipoprotein (blc) surrounding the ampR-ampC genes in C. freundii were identified, and insertion sequence (IS26) elements were observed on both sides of the sequences identified (forming an IS26 composite transposon); these results confirm the evidence of the translocation of a beta-lactamase-associated gene region from the chromosome to a plasmid. Finally, we describe a novel plasmid-encoded AmpC beta-lactamase, CFE-1, with an ampR gene derived from C. freundii.
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Affiliation(s)
- Ryuichi Nakano
- Department of Microbiology, School of Medicine and Environmental Infectious Disease, Graduate School of Medical Sciences, Kitasato University, Sagamihara, Kanagawa, Japan
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Weng SF, Lin JW, Chen CH, Chen YY, Tseng YH, Tseng YH. Constitutive expression of a chromosomal class A (BJM group 2) beta-lactamase in Xanthomonas campestris. Antimicrob Agents Chemother 2004; 48:209-15. [PMID: 14693541 PMCID: PMC310161 DOI: 10.1128/aac.48.1.209-215.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequencing of the upstream region of the beta-lactamase gene from Xanthomonas campestris pv. campestris 11 (bla(XCC-1)) revealed the cognate ampR1 gene (289 amino acids, 31 kDa). It runs divergently from bla(XCC-1) with a 100-bp intergenic region (IG) containing partially overlapped promoters with structural features typical of the bla-ampR IG. The deduced AmpR1 protein shows significant identity in amino acid sequence and conserved motifs with AmpR proteins of other species, e.g., of Pseudomonas aeruginosa (58.2% amino acid identity). Results of insertional mutation, complementation tests, and beta-lactamase assays suggested that expression of bla(XCC-1) was constitutive and dependent on AmpR1. Four bla genes and two ampR genes are present in the fully sequenced X. campestris pv. campestris ATCC 33913 genome, with XCC3039 and XCC3040 considered the analogues of bla(XCC-1) and ampR1, respectively. An ampR1 homologue was detected by Southern hybridization in the ampicillin-resistant Xanthomonas strains, which appear to express beta-lactamase constitutively. Although the significance remains to be studied, constitutive expression of beta-lactamase by a widespread bacterial genus raises environmental concerns regarding the dissemination of resistance genes.
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Affiliation(s)
- Shu-Fen Weng
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
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40
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Siu LK, Lu PL, Chen JY, Lin FM, Chang SC. High-level expression of ampC beta-lactamase due to insertion of nucleotides between -10 and -35 promoter sequences in Escherichia coli clinical isolates: cases not responsive to extended-spectrum-cephalosporin treatment. Antimicrob Agents Chemother 2003; 47:2138-44. [PMID: 12821459 PMCID: PMC161857 DOI: 10.1128/aac.47.7.2138-2144.2003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two Escherichia coli isolates were recovered from the blood of two cancer patients and were demonstrated to produce high levels of the AmpC beta-lactamase with isoelectric points of >9.0. The hypertranscription of ampC RNA was observed by Northern blot hybridization in both isolates. One isolate (isolate EC44) had a point mutation (G-->A at position -28) and insertion of thymidine between positions -20 and -19 of the ampC promoter gene (GenBank accession no. AE000487). The single nucleotide insertion of T between positions -19 and -20 created an optimal distance (17 bp) in the Pribnow box for ampC hyperproduction. The other isolate (isolate EC38) had two point mutations (G-->A at position -28 and C-->T at position +58) and a 2-base (GT) insertion between positions -14 and -15. Although the insertion of GT between positions -14 and -15 may create a new promoter next to the original promoter, cloning of the ampC region with truncated nucleotides of the original -35 region of EC38 failed to verify the hypothesis that a new promoter would be created by such a nucleotide insertion. Instead, multiple start sites for ampC transcription at -1, +1, +2, and +3 were observed in an S1 nuclease protection assay. These results suggest that the RNA polymerase is flexible in the selection of a start site in ampC hypertranscription. In conclusion, nucleotide insertions between the -35 and -10 ampC promoter sequences was the mechanism for the hyperproduction of AmpC beta-lactamase and resistance to oxyimino-cephalosporins. The failure of the two patients to respond to treatment with oxyimino-cephalosporins highlights the important role of such a resistance mechanism in the clinical setting.
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Affiliation(s)
- L K Siu
- Division of Clinical Research, National Health Research Institutes, National Taiwan University Hospital, Taipei, Taiwan.
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41
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Athanassiou G, Michaleas S, Lada-Chitiroglou E, Tsitsa T, Antoniadou-Vyza E. Antimicrobial activity of beta-lactam antibiotics against clinical pathogens after molecular inclusion in several cyclodextrins. A novel approach to bacterial resistance. J Pharm Pharmacol 2003; 55:291-300. [PMID: 12724033 DOI: 10.1211/002235702649] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Recognition and uptake by specific cellular receptors and transport systems for cyclodextrins have been demonstrated. Based on this concept, natural and synthetically modified cyclodextrins were used as drug carriers. Several beta-lactam antibiotics were selected and their inclusion complexes with different cyclodextrins were prepared (molar ratio ranging from 1:1 to 1:3). The complex formation, in aqueous solution, was monitored and optimum complexation conditions were selected. The inclusion of the active molecules in the cyclodextrin cavity was confirmed by (1)H NMR spectroscopy. Specific HPLC methods for the quantitation of antibiotics in the presence of cyclodextrins were developed and their chemical stability under complexation conditions was confirmed. Antimicrobial activity of drug-cyclodextrin complexes, in terms of minimum inhibitory concentration (MIC), were compared with the corresponding values of uncomplexed free molecules. A wide range of clinical pathogens and known beta-lactamase-producing strains were tested. The activity of the cyclodextrin-included antibiotics was increased, particularly against Gram-negative clinical strains. The nature and degree of substitution on cyclodextrin macromolecules may be the predominant factor in the observed improvement in antimicrobial activity. We believe that the proposed methodology is a novel approach to the microbial resistance problem and will trigger research towards the development of new cyclodextrin derivatives bearing the ability to increase the uptake of included antimicrobial molecules through intensification of the corresponding molecular recognition phenomena.
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Affiliation(s)
- G Athanassiou
- Department of Microbiology, School of Medicine, University of Athens, Goudi, Athens 11527, Greece
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42
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Choi SH, Kim YS, Chung JW, Kim TH, Choo EJ, Kim MN, Kim BN, Kim NJ, Woo JH, Ryu J. Serratia bacteremia in a large university hospital: trends in antibiotic resistance during 10 years and implications for antibiotic use. Infect Control Hosp Epidemiol 2002; 23:740-7. [PMID: 12517017 DOI: 10.1086/502004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To identify antibiotic resistance trends and risk factors for resistance of Serratia species to third-generation cephalosporins. DESIGN Retrospective survey of medical records. SETTING A 2,200-bed, tertiary-care hospital. PATIENTS One hundred twenty-two patients with Serratia bacteremia between January 1991 and June 2001. METHODS Infectious disease physicians collected data from medical records regarding patient demographics, underlying disease or condition, portal of entry, microorganism, antibiogram, complications, antibiotics received, and outcome. RESULTS Among 122 Serratia isolates, 117 (95.9%) were Serratia marcescens and 110 (90.2%) were of nosocomial origin. During the study period, the 122 isolates showed a high rate of resistance to third-generation cephalosporins (45.9%) and extended-spectrum penicillins (56.6%). The resistance rate to ciprofloxacin was 32.0%. The resistance rate to third-generation cephalosporins increased from 31.7% for 1991 to 1995 to 54.9% for 1996 to 1998 and 50.0% for 1999 to 2001. In the multivariate analysis, prior use of a second-generation cephalosporin (adjusted odds ratio [OR], 5.90; 95% confidence interval [CI90], 1.41 to 24.6; P = .015) or a third-generation cephalosporin (OR, 3.26; CI95, 1.20 to 8.87; P = .020) was a strong independent risk factor for resistance to third-generation cephalosporins. The overall case-fatality rate was 25.4% (Serratia bacteremia-related case-fatality rate, 13.1%). CONCLUSION Prior use of a second- or third-generation cephalosporin was the most important risk factor for bacteremia with Serratia resistant to third-generation cephalosporins, suggesting the need for antibiotic control. The potential role of patient-to-patient spread could not be fully evaluated in this retrospective study.
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Affiliation(s)
- Sang-Ho Choi
- Division of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
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43
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Goldstein FW. Cephalosporinase induction and cephalosporin resistance: a longstanding misinterpretation. Clin Microbiol Infect 2002; 8:823-5. [PMID: 12519358 DOI: 10.1046/j.1469-0691.2002.00492.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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44
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Naas T, Aubert D, Fortineau N, Nordmann P. Cloning and sequencing of the beta-lactamase gene and surrounding DNA sequences of Citrobacter braakii, Citrobacter murliniae, Citrobacter werkmanii, Escherichia fergusonii and Enterobacter cancerogenus. FEMS Microbiol Lett 2002; 215:81-7. [PMID: 12393205 DOI: 10.1111/j.1574-6968.2002.tb11374.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
To further identify the origins of plasmid-mediated cephalosporinases that are currently spreading worldwide, the chromosomal beta-lactamase genes of Citrobacter braakii, Citrobacter murliniae, Citrobacter werkmanii reference strains and of Escherichia fergusonii and Enterobacter cancerogenus clinical isolates were cloned and expressed into Escherichia coli and sequenced. These beta-lactamases had all a single pI value >8 and conferred a typical AmpC-type resistance pattern in E. coli recombinant strains. The cloned inserts obtained from genomic DNAs of each strain encoded Ambler class C beta-lactamases. The AmpC-type enzymes of C. murliniae, C. braakii and C. werkmanii shared 99%, 96% and 95% amino acid sequence identity, respectively, with chromosomal AmpC beta-lactamases from Citrobacter freundii. The AmpC-type enzyme of E. cancerogenus shared 85% amino acid sequence identity with the chromosomal AmpC beta-lactamase of Enterobacter cloacae OUDhyp and the AmpC-type enzyme of E. fergusonii shared 96% amino acid sequence identity with that of E. coli K12. The ampC genes, except for E. fergusonii, were associated with genes homologous to regulatory ampR genes of other chromosomal class C beta-lactamases that explain inducibility of beta-lactamase expression in these strains. This work provides further evidence of the molecular heterogeneity of class C beta-lactamases.
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Affiliation(s)
- Thierry Naas
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre Cedex, France.
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45
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Powers RA, Shoichet BK. Structure-based approach for binding site identification on AmpC beta-lactamase. J Med Chem 2002; 45:3222-34. [PMID: 12109906 DOI: 10.1021/jm020002p] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Beta-lactamases are the most widespread resistance mechanism to beta-lactam antibiotics and are an increasing menace to public health. Several beta-lactamase structures have been determined, making this enzyme an attractive target for structure-based drug design. To facilitate inhibitor design for the class C beta-lactamase AmpC, binding site "hot spots" on the enzyme were identified using experimental and computational approaches. Experimentally, X-ray crystal structures of AmpC in complexes with four boronic acid inhibitors and a higher resolution (1.72 A) native apo structure were determined. Along with previously determined structures of AmpC in complexes with five other boronic acid inhibitors and four beta-lactams, consensus binding sites were identified. Computationally, the programs GRID, MCSS, and X-SITE were used to predict potential binding site hot spots on AmpC. Several consensus binding sites were identified from the crystal structures. An amide recognition site was identified by the interaction between the carbonyl oxygen in the R1 side chain of beta-lactams and the atom Ndelta2 of the conserved Asn152. Surprisingly, this site also recognizes the aryl rings of arylboronic acids, appearing to form quadrupole-dipole interactions with Asn152. The highly conserved "oxyanion" hole defines a site that recognizes both carbonyl and hydroxyl groups. A hydroxyl binding site was identified by the O2 hydroxyl in the boronic acids, which hydrogen bonds with Tyr150 and a conserved water. A hydrophobic site is formed by Leu119 and Leu293. A carboxylate binding site was identified by the ubiquitous C3(4) carboxylate of the beta-lactams, which interacts with Asn346 and Arg349. Four water sites were identified by ordered waters observed in most of the structures; these waters form extensive hydrogen-bonding networks with AmpC and occasionally the ligand. Predictions by the computational programs showed some correlation with the experimentally observed binding sites. Several sites were not predicted, but novel binding sites were suggested. Taken together, a map of binding site hot spots found on AmpC, along with information on the functionality recognized at each site, was constructed. This map may be useful for structure-based inhibitor design against AmpC.
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Affiliation(s)
- Rachel A Powers
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611, USA
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Valtonen SJ, Kurittu JS, Karp MT. A luminescent Escherichia coli biosensor for the high throughput detection of beta-lactams. JOURNAL OF BIOMOLECULAR SCREENING 2002; 7:127-34. [PMID: 12006111 DOI: 10.1177/108705710200700205] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A group-specific bioluminescent Escherichia coli strain for studying the action of beta-lactam antibiotics is described. The strain contains a plasmid, pBlaLux1, in which the luciferase genes from Photorhabdus luminescens are inserted under the control of the beta-lactam-responsive element ampR/ampC from Citrobacter freundii. In the presence of beta-lactams, the bacterial cells are induced to express the luciferase enzyme and three additional enzymes generating the substrate for the luciferase reaction. This biosensor for beta-lactams does not need any substrate or cofactor additions, and the bioluminescence can be measured very sensitively in real time by using a luminometer. Basic parameters affecting the light production and induction in the gram-negative model organism E. coli SNO301/pBlaLux1 by various beta-lactams were studied. The dose-response curves were bell shaped, indicating toxic effects for the sensor strain at high concentrations of beta-lactams. Various beta-lactams had fairly different assay ranges: ampicillin, 0.05-1.0 microg/ml; piperacillin, 0.0025-25 microg/ml; imipenem, 0.0025-0.25 microg/ml; cephapirin, 0.025-2.5 microg/ml; cefoxitin, 0.0025-1.5 microg/ml; and oxacillin, 25-500 microg/ml. Also, the induction coefficients (signal over background noninduced control) varied considerably from 3 to 158 in a 2-hour assay. Different non-beta-lactam antibiotics did not cause induction. Because the assay can be automated using microplate technologies, the approach may be suitable for higher throughput analysis of beta-lactam action.
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Affiliation(s)
- Satu J Valtonen
- Karolinska Institutet, Center for Genomics and Bioinformatics, Stockholm, Sweden
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Liassine N, Madec S, Ninet B, Metral C, Fouchereau-Peron M, Labia R, Auckenthaler R. Postneurosurgical meningitis due to Proteus penneri with selection of a ceftriaxone-resistant isolate: analysis of chromosomal class A beta-lactamase HugA and its LysR-type regulatory protein HugR. Antimicrob Agents Chemother 2002; 46:216-9. [PMID: 11751137 PMCID: PMC126972 DOI: 10.1128/aac.46.1.216-219.2002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report on a case of a postneurosurgical meningitis due to ceftriaxone-susceptible Proteus penneri, with selection of a ceftriaxone-resistant isolate following treatment with ceftriaxone. The isolates presented identical patterns by pulsed-field gel electrophoresis and produced a single beta-lactamase named HugA with an isoelectric point of 6.7. The ceftriaxone-resistant isolate hyperproduced the beta-lactamase (increase in the level of production, about 90-fold). The sequences of the hugA beta-lactamase gene and its regulator, hugR, were identical in both P. penneri strains and had 85.96% homology with those of Proteus vulgaris. The HugA beta-lactamase belongs to molecular class A, and the transcriptional regulator HugR belongs to the LysR family.
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Affiliation(s)
- Nadia Liassine
- Central Laboratory of Bacteriology, University Hospital, Geneva, Switzerland.
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Naas T, Massuard S, Garnier F, Nordmann P. AmpD is required for regulation of expression of NmcA, a carbapenem-hydrolyzing beta-lactamase of Enterobacter cloacae. Antimicrob Agents Chemother 2001; 45:2908-15. [PMID: 11557489 PMCID: PMC90751 DOI: 10.1128/aac.45.10.2908-2915.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To further elucidate the induction process of the carbapenem-hydrolyzing beta-lactamase of Ambler class A, NmcA, ampD genes of the wild-type (WT) strain and of ceftazidime-resistant mutants of Enterobacter cloacae NOR-1 were cloned and tested in transcomplementation experiments. Ceftazidime-resistant E. cloacae NOR-1 mutants exhibited derepressed expression of the AmpC-type cephalosporinase and of the carbapenem-hydrolyzing beta-lactamase NmcA. The ampD genes of Escherichia coli and E. cloacae WT NOR-1 transcomplemented the ceftazidime-resistant E. cloacae NOR-1 mutants to the WT level of beta-lactamase expression, while the mutated ampD alleles of E. cloacae NOR-1 failed to do so. The deduced E. cloacae NOR-1 WT AmpD protein exhibited 95 and 91% amino acid identity with the E. cloacae O29 and E. cloacae 14 WT AmpD proteins, respectively. Of the 12 ceftazidime-resistant E. cloacae NOR-1 strains, 3 had AmpD proteins with amino acid changes, while the others had truncated AmpD proteins. Most of these mutations were located outside the conserved regions that link the AmpD proteins to the cell wall hydrolases. AmpD from E. cloacae NOR-1 is involved in the regulation of expression of both beta-lactamases (NmcA and AmpC), suggesting that structurally unrelated genes may be under the control of an identical genetic system.
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Affiliation(s)
- T Naas
- Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 78 rue du Général Leclerc, 94275 Le Kremlin-Bicêtre Cedex, France.
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Mammeri H, Laurans G, Eveillard M, Castelain S, Eb F. Coexistence of SHV-4- and TEM-24-producing Enterobacter aerogenes strains before a large outbreak of TEM-24-producing strains in a French hospital. J Clin Microbiol 2001; 39:2184-90. [PMID: 11376055 PMCID: PMC88109 DOI: 10.1128/jcm.39.6.2184-2190.2001] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years. All extended-spectrum beta-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing. Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients. Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996. This study shows that TEM-24-producing E. aerogenes is an epidemic clone that is well established in the hospital's ecology and able to spread throughout wards. The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen.
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Affiliation(s)
- H Mammeri
- Laboratory of Bacteriology-Hygiene, University Hospital Nord, 80054 Amiens Cédex 01, France.
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Nadjar D, Labia R, Cerceau C, Bizet C, Philippon A, Arlet G. Molecular characterization of chromosomal class C beta-lactamase and its regulatory gene in Ochrobactrum anthropi. Antimicrob Agents Chemother 2001; 45:2324-30. [PMID: 11451692 PMCID: PMC90649 DOI: 10.1128/aac.45.8.2324-2330.2001] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ochrobactrum anthropi, formerly known as CDC group Vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. It is highly resistant to all beta-lactams except imipenem. A clinical isolate, SLO74, and six reference strains were tested. MICs of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 microg/ml and of cefepime were 64 to >128 microg/ml. Clavulanic acid was ineffective and tazobactam had a weak effect in association with piperacillin. Two genes, ampR and ampC, were cloned by inserting restriction fragments of genomic DNA from the clinical strain O. anthropi SLO74 into pBK-CMV to give the recombinant plasmid pBK-OA1. The pattern of resistance to beta-lactams of this clone was similar to that of the parental strain, except for its resistance to cefepime (MIC, 0.5 ,micro/ml). The deduced amino acid sequence of the AmpC beta-lactamase (pI, 8.9) was only 41 to 52% identical to the sequence of other chromosomally encoded and plasmid-encoded class C beta-lactamases. The kinetic properties of this beta-lactamase were typical for this class of beta-lactamases. Upstream from the ampC gene, the ampR gene encodes a protein with a sequence that is 46 to 62% identical to those of other AmpR proteins and with an amino-terminal DNA-binding domain typical of transcriptional activators of the Lys-R family. The deduced amino acid sequences of the ampC genes of the six reference strains were 96 to 99% identical to the sequence of the clinical strain. The beta-lactamase characterized from strain SLO74 was named OCH-1 (gene, bla(OCH-I)).
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Affiliation(s)
- D Nadjar
- Laboratoire de Bactériologie, Hôpital Tenon, UFR Saint-Antoine, Paris, France
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