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Schmidt JJ, Remme DCLE, Eisfeld J, Brandenburg VB, Bille H, Narberhaus F. The LysR-type transcription factor LsrB regulates beta-lactam resistance in Agrobacterium tumefaciens. Mol Microbiol 2024; 121:26-39. [PMID: 37985428 DOI: 10.1111/mmi.15191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/20/2023] [Accepted: 10/28/2023] [Indexed: 11/22/2023]
Abstract
Agrobacterium tumefaciens is a plant pathogen, broadly known as the causal agent of the crown gall disease. The soil bacterium is naturally resistant to beta-lactam antibiotics by utilizing the inducible beta-lactamase AmpC. Our picture on the condition-dependent regulation of ampC expression is incomplete. A known regulator is AmpR controlling the transcription of ampC in response to unrecycled muropeptides as a signal for cell wall stress. In our study, we uncovered the global transcriptional regulator LsrB as a critical player acting upstream of AmpR. Deletion of lsrB led to severe ampicillin and penicillin sensitivity, which could be restored to wild-type levels by lsrB complementation. By transcriptome profiling via RNA-Seq and qRT-PCR and by electrophoretic mobility shift assays, we show that ampD coding for an anhydroamidase involved in peptidoglycan recycling is under direct negative control by LsrB. Controlling AmpD levels by the LysR-type regulator in turn impacts the cytoplasmic concentration of cell wall degradation products and thereby the AmpR-mediated regulation of ampC. Our results substantially expand the existing model of inducible beta-lactam resistance in A. tumefaciens by establishing LsrB as higher-level transcriptional regulator.
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Affiliation(s)
| | | | - Jessica Eisfeld
- Medical Microbiology, Ruhr University Bochum, Bochum, Germany
| | | | - Hannah Bille
- Microbial Biology, Ruhr University Bochum, Bochum, Germany
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2
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Zhao C, Li Y, Zhao J, Li H, Xu J, Gao Z, Ding C, Song YY. A "Test-to-Treat" Pad for Real-Time Visual Monitoring of Bacterial Infection and On-Site Performing Smart Therapy Strategies. ACS NANO 2023. [PMID: 37399243 DOI: 10.1021/acsnano.3c01158] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Skin infections are major threats to human health, causing ∼500 incidences per 10 000 person-year. In patients with diabetes mellitus, particularly, skin infections are often accompanied by a slow healing process, amputation, and even death. Timely diagnosis of skin infection strains and on-site therapy are vital in human health and safety. Herein, a double-layered "test-to-treat" pad is developed for the visual monitoring and selective treatment of drug-sensitive (DS)/drug-resistant (DR) bacterial infections. The inner layer (using carrageenan hydrogel as a scaffold) is loaded with bacteria indicators and an acid-responsive drug (Fe-carbenicillin frameworks) for infection detection and DS bacteria inactivation. The outer layer is a mechanoluminescence material (ML, CaZnOS:Mn2+) and visible-light responsive photocatalyst (Pt@TiO2) incorporated elastic polydimethylsiloxane (PDMS). On the basis of the colorimetric sensing result (yellow for DS-bacterial infection and red for DR-bacterial infection), a suitable antibacterial strategy is guided and then performed. Two available bactericidal routes provided by double pad layers reflect the advantage. The controllable and effective killing of DR bacteria is realized by in situ generated reactive oxygen species (ROSs) from the combination of Pt@TiO2 and ML under mechanical force, avoiding physical light sources and alleviating off-target side effects of ROS in biomedical therapy. As a proof-of-concept, the "test-to-treat" pad is applied as a wearable wound dressing for sensing and selectively dealing with DS/DR bacterial infections in vitro and in vivo. This multifunctional design effectively reduces antibiotic abuse and accelerates wound healing, providing an innovative and promising Band-Aid strategy in point-of-care diagnosis and therapy.
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Affiliation(s)
| | | | | | - Hailong Li
- NHC Key Laboratory of AIDS Immunology (China Medical University), National Clinical Research Center for Laboratory Medicine, The First Affiliated Hospital of China Medical University, Shenyang 110001, P. R. China
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3
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Adaptive responses of Pseudomonas aeruginosa to treatment with antibiotics. Antimicrob Agents Chemother 2021; 66:e0087821. [PMID: 34748386 DOI: 10.1128/aac.00878-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas aeruginosa is among the highest priority pathogens for drug development, because of its resistance to antibiotics, extraordinary adaptability, and persistence. Anti-pseudomonal research is strongly encouraged to address the acute scarcity of innovative antimicrobial lead structures. In an effort to understand the physiological response of P. aeruginosa to clinically relevant antibiotics, we investigated the proteome after exposure to ciprofloxacin, levofloxacin, rifampicin, gentamicin, tobramycin, azithromycin, tigecycline, polymyxin B, colistin, ceftazidime, meropenem, and piperacillin/tazobactam. We further investigated the response to CHIR-90, which represents a promising class of lipopolysaccharide biosynthesis inhibitors currently under evaluation. Radioactive pulse-labeling of newly synthesized proteins followed by 2D-PAGE was used to monitor the acute response of P. aeruginosa to antibiotic treatment. The proteomic profiles provide insights into the cellular defense strategies for each antibiotic. A mathematical comparison of these response profiles based on upregulated marker proteins revealed similarities of responses to antibiotics acting on the same target area. This study provides insights into the effects of commonly used antibiotics on P. aeruginosa and lays the foundation for the comparative analysis of the impact of novel compounds with precedented and unprecedented modes of action.
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Hilton SH, Hall C, Nguyen HT, Everitt ML, DeShong P, White IM. Phenotypically distinguishing ESBL-producing pathogens using paper-based surface enhanced Raman sensors. Anal Chim Acta 2020; 1127:207-216. [PMID: 32800126 PMCID: PMC10069952 DOI: 10.1016/j.aca.2020.06.068] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/10/2020] [Accepted: 06/26/2020] [Indexed: 01/14/2023]
Abstract
Antimicrobial stewardship practices are critical in preventing the further erosion of treatment options for bacterial infections. Yet, at the same time, determination of an infection's antimicrobial susceptibility requires multiple rounds of culture and expensive lab automation systems. In this work, we report the use of paper-based surface enhanced Raman spectroscopy (SERS) sensors and portable instrumentation to phenotypically discriminate multi-drug resistance with fewer culture steps than conventional clinical microbiology. Specifically, we demonstrate the identification of resistance to varying generations of β-lactam antibiotics by detecting the activity of particular β-lactamase enzymes in a multiplexed assay. The method utilizes molecular reporters that consist of β-lactams with SERS barcodes. Hydrolysis of the β-lactam by β-lactamase enzymes in the sample expels the barcode; the released sulfur-containing barcode is then detected via SERS. Using this approach, we demonstrate the differentiation of E. coli strains with (1) extended spectrum β-lactamase (ESBL), (2) narrow-spectrum β-lactamase, and (3) no resistance, using only a single measurement on a single sample. In addition, we experimentally validate an approach to expand the library of reporters through the simple chemical synthesis of new barcoded β-lactams. Importantly, the reported method determines the susceptibility based on phenotypic β-lactamase activity, which is aligned with current microbiology lab standards. This new method will enable the precise selection of effective β-lactam antibiotics (as opposed to defaulting to drugs of last resort) faster than current methods while using simple steps and low-cost portable instrumentation.
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Affiliation(s)
- Shannon H Hilton
- Fischell Department of Bioengineering, 8278 Paint Branch Drive, University of Maryland, College Park, MD, USA
| | - Connor Hall
- Fischell Department of Bioengineering, 8278 Paint Branch Drive, University of Maryland, College Park, MD, USA
| | - Hieu T Nguyen
- Fischell Department of Bioengineering, 8278 Paint Branch Drive, University of Maryland, College Park, MD, USA
| | - Micaela L Everitt
- Fischell Department of Bioengineering, 8278 Paint Branch Drive, University of Maryland, College Park, MD, USA
| | - Philip DeShong
- Department of Chemistry and Biochemistry, 8051 Regents Drive, University of Maryland, College Park, MD, USA
| | - Ian M White
- Fischell Department of Bioengineering, 8278 Paint Branch Drive, University of Maryland, College Park, MD, USA.
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Shrivastav A, Sharma RK, Shrivastava N, Gautam V, Jain SK. Study of inhibitory potential and percent inhibition of oil of Syzygium aromaticum and leaves of Ocimum sanctum on ESBL enzyme from Escherichia coli in broilers of Jabalpur. Indian J Pharmacol 2019; 51:337-342. [PMID: 31831923 PMCID: PMC6892005 DOI: 10.4103/ijp.ijp_87_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 10/04/2019] [Accepted: 11/10/2019] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE: The inhibitory potential and percent inhibition of Syzygium aromaticum oil and fresh juice of Ocimum sanctum leaves on beta-lactamase enzyme of cecal samples of healthy broilers were studied on samples phenotypically positive for extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli. MATERIALS AND METHODS: Four hundred cecal samples screened for ESBL-producing E. coli were collected from 38 poultry sale outlets located in Jabalpur. The effect of S. aromaticum oil and O. sanctum leaves was seen by colorimetric assay with CENTA and Nitrocefin as chromogenic substrate. RESULTS: Mean absorbance value was inversely propotional to the inhibitory potential. Syzigium aromaticum exhibited 0.4±0.02 and 0.41±0.03 mean absorbance value, 28 per cent and 27 per cent of inhibition with CENTA and Nitrocefin respectively. Ocimum sanctum mean absorbance value and per cent inhibition with CENTA and Nitrocefin was 2.03±0.02 and 10.0 ; 1.97±0.06 and 10.0 respectively (p>0.05) showing non- significant difference in CENTA and Nitrocefin activity. Tazobactum (100 μM) as standard control exhibited a mean absorbance value of 0.12 ± 0.01 and 0.13 ± 0.01 and percent inhibition of 99.88 and 98 against CENTA and Nitrocefin, respectively. Combination of Ocimum sanctum and Syzigium aromaticum showed range of 1.69±0.05 to 1.90±0.08 1.61±0.06 to 1.92±0.08 of absorbance value with per cent inhibition of 14 to 15.9 with CENTA and Nitrocefin respectively. CONCLUSION: The results depicted that the inhibition of beta-lactamase enzyme activity with S. aromaticum oil was higher than that of O. sanctum leaf juice, and combination of both the herbs showed not much difference in activity.
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Affiliation(s)
- Arpita Shrivastav
- Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur, Madhya Pradesh, India
| | - R K Sharma
- Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur, Madhya Pradesh, India
| | - Neeraj Shrivastava
- Department of Microbiology, College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur, Madhya Pradesh, India
| | - Vidhi Gautam
- Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur, Madhya Pradesh, India
| | - Sachin Kumar Jain
- Department of Pharmacology and Toxicology, College of Veterinary Science and Animal Husbandry, NDVSU, Jabalpur, Madhya Pradesh, India
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6
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Goertz JP, White IM. Phase-Change Partitions for Thermal Automation of Multistep Reactions. Anal Chem 2018; 90:3708-3713. [DOI: 10.1021/acs.analchem.7b05400] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- John P. Goertz
- Department of Bioengineering, University of Maryland, College Park, Maryland 20742, United States
| | - Ian M. White
- Department of Bioengineering, University of Maryland, College Park, Maryland 20742, United States
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7
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Rohde A, Hammerl JA, Al Dahouk S. Rapid screening for antibiotic resistance elements on the RNA transcript, protein and enzymatic activity level. Ann Clin Microbiol Antimicrob 2016; 15:55. [PMID: 27663856 PMCID: PMC5035493 DOI: 10.1186/s12941-016-0167-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 09/13/2016] [Indexed: 11/29/2022] Open
Abstract
Background The emerging threat posed by antibiotic resistance has affected public health systems all over the world. Surveillance of resistant bacteria in clinical settings and identifying them in mixed cultures is of paramount importance and can contribute to the control of their spreading. Culture-independent monitoring approaches are highly desirable, since they yield results much faster than traditional susceptibility testing. However, many rapid molecular methods like PCR only detect the sole presence of a potential resistance gene, do not provide information regarding efficient transcription, expression and functionality and, in addition, cannot assign resistance genes to species level in mixed cultures. Methods By using plasmid-encoded TEM β-lactamase mediated ampicillin resistances as a proof of principle system, we (1) developed a fluorescence in situ hybridization-test (FISH) capable to detect the respective mRNAs, (2) implemented an immunofluorescence test to identify the corresponding proteins and (3) compared these two microscopic tests with an established colorimetric nitrocefin assay to assess the enzymatic activity. Results All three methods proved to be suitable for the testing of antibiotic resistance, but only FISH and immunofluorescence were able to differentiate between susceptible and resistant bacteria on the single cell level and can be combined with simultaneous species identification. Conclusions Fluorescence in situ hybridization and immunofluorescence tests are promising techniques in susceptibility testing since they bridge the gap between the slow, but accurate and sound cultural methods and molecular detection methods like PCR with much less functional relevance. Electronic supplementary material The online version of this article (doi:10.1186/s12941-016-0167-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexander Rohde
- Department of Biological Safety, Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277, Berlin, Germany. .,Department of Biology, Chemistry and Pharmacy, Free University Berlin, Takustr. 3, 14195, Berlin, Germany.
| | - Jens Andre Hammerl
- Department of Biological Safety, Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277, Berlin, Germany
| | - Sascha Al Dahouk
- Department of Biological Safety, Federal Institute for Risk Assessment, Diedersdorfer Weg 1, 12277, Berlin, Germany
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Lee SY, Brem J, Pettinati I, Claridge TDW, Gileadi O, Schofield CJ, McHugh PJ. Cephalosporins inhibit human metallo β-lactamase fold DNA repair nucleases SNM1A and SNM1B/apollo. Chem Commun (Camb) 2016; 52:6727-30. [PMID: 27121860 PMCID: PMC5063058 DOI: 10.1039/c6cc00529b] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/18/2016] [Indexed: 12/19/2022]
Abstract
Bacterial metallo-β-lactamases (MBLs) are involved in resistance to β-lactam antibiotics including cephalosporins. Human SNM1A and SNM1B are MBL superfamily exonucleases that play a key role in the repair of DNA interstrand cross-links, which are induced by antitumour chemotherapeutics, and are therefore targets for cancer chemosensitization. We report that cephalosporins are competitive inhibitors of SNM1A and SNM1B exonuclease activity; both the intact β-lactam and their hydrolysed products are active. This discovery provides a lead for the development of potent and selective SNM1A and SNM1B inhibitors.
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Affiliation(s)
- Sook Y Lee
- Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK. and Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Jürgen Brem
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Ilaria Pettinati
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Timothy D W Claridge
- Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
| | - Opher Gileadi
- Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, University of Oxford, OX3 7DQ, UK
| | | | - Peter J McHugh
- Department of Oncology, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK.
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9
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Rochelet M, Solanas S, Betelli L, Neuwirth C, Vienney F, Hartmann A. Amperometric detection of extended-spectrum β-lactamase activity: application to the characterization of resistant E. coli strains. Analyst 2015; 140:3551-6. [PMID: 25849107 DOI: 10.1039/c4an01786b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The amperometric detection of extended-spectrum β-lactamase (ESBL) with carbon screen-printed sensors was investigated in the presence of the Nitrocefin, a commercially-available β-lactamase chromogenic cephalosporin substrate. Using an ESBL isolated from a clinical sample, it was shown for the first time that the intensity of a specific anodic pic current (EP = ∼+0.3 V vs. Ag/AgCl) resulting from the catalytic hydrolysis of the β-lactam ring was proportional to the amount of ESBL. The proof-of-principle of a novel susceptibility assay for the rapid and accurate identification of ESBL- producing bacteria was then demonstrated. The detection scheme relied on (i) the culture of the sample in a medium containing the cefotaxime supplemented or not with the clavulanic acid inhibitor to allow the specific determination of ESBL producers (ii) followed by the incubation of the bacteria with the Nitrocefin and (iii) the measurement of the enzyme product by cyclic voltammetry. The amperometric assay was further applied to the characterization of E. coli strains and to the quantification of the ESBL producers. A detection limit of 5 × 10(4) cfu mL(-1) ESBL-producing E. coli was achieved after a 10 min incubation time. In contrast to the approved routine assays, the electrochemical approach, which did not require isolated colonies to be performed, provided quantified results regarding ESBL activity within a few hours. Finally, owing to its cost-effectiveness, portability and simplicity, this test holds great promise for clinical and environmental applications.
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Affiliation(s)
- Murielle Rochelet
- Université de Bourgogne, UMR1347 Agroécologie, 17 rue Sully, 21000 Dijon, France.
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10
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Erdem SS, Khan S, Palanisami A, Hasan T. Rapid, low-cost fluorescent assay of β-lactamase-derived antibiotic resistance and related antibiotic susceptibility. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:105007. [PMID: 25321396 PMCID: PMC4193078 DOI: 10.1117/1.jbo.19.10.105007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/25/2014] [Accepted: 07/03/2014] [Indexed: 06/04/2023]
Abstract
Antibiotic resistance (AR) is increasingly prevalent in low and middle income countries (LMICs), but the extent of the problem is poorly understood. This lack of knowledge is a critical deficiency, leaving local health authorities essentially blind to AR outbreaks and crippling their ability to provide effective treatment guidelines. The crux of the problem is the lack of microbiology laboratory capacity available in LMICs. To address this unmet need, we demonstrate a rapid and simple test of β -lactamase resistance (the most common form of AR) that uses a modified β -lactam structure decorated with two fluorophores quenched due to their close proximity. When the β -lactam core is cleaved by β -lactamase, the fluorophores dequench, allowing assay speeds of 20 min to be obtained with a simple, streamlined protocol. Furthermore, by testing in competition with antibiotics, the β -lactamase-associated antibiotic susceptibility can also be extracted. This assay can be easily implemented into standard lab work flows to provide near real-time information of β -lactamase resistance, both for epidemiological purposes as well as individualized patient care.
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Affiliation(s)
- S. Sibel Erdem
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Shazia Khan
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Akilan Palanisami
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
| | - Tayyaba Hasan
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
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11
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Navratna V, Nadig S, Sood V, Prasad K, Arakere G, Gopal B. Molecular basis for the role of Staphylococcus aureus penicillin binding protein 4 in antimicrobial resistance. J Bacteriol 2010; 192:134-44. [PMID: 19854906 PMCID: PMC2798245 DOI: 10.1128/jb.00822-09] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 10/02/2009] [Indexed: 11/20/2022] Open
Abstract
Penicillin binding proteins (PBPs) are membrane-associated proteins that catalyze the final step of murein biosynthesis. These proteins function as either transpeptidases or carboxypeptidases and in a few cases demonstrate transglycosylase activity. Both transpeptidase and carboxypeptidase activities of PBPs occur at the D-Ala-D-Ala terminus of a murein precursor containing a disaccharide pentapeptide comprising N-acetylglucosamine and N-acetyl-muramic acid-L-Ala-D-Glu-L-Lys-D-Ala-D-Ala. Beta-lactam antibiotics inhibit these enzymes by competing with the pentapeptide precursor for binding to the active site of the enzyme. Here we describe the crystal structure, biochemical characteristics, and expression profile of PBP4, a low-molecular-mass PBP from Staphylococcus aureus strain COL. The crystal structures of PBP4-antibiotic complexes reported here were determined by molecular replacement, using the atomic coordinates deposited by the New York Structural Genomics Consortium. While the pbp4 gene is not essential for the viability of S. aureus, the knockout phenotype of this gene is characterized by a marked reduction in cross-linked muropeptide and increased vancomycin resistance. Unlike other PBPs, we note that expression of PBP4 was not substantially altered under different experimental conditions, nor did it change across representative hospital- or community-associated strains of S. aureus that were examined. In vitro data on purified recombinant S. aureus PBP4 suggest that it is a beta-lactamase and is not trapped as an acyl intermediate with beta-lactam antibiotics. Put together, the expression analysis and biochemical features of PBP4 provide a framework for understanding the function of this protein in S. aureus and its role in antimicrobial resistance.
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Affiliation(s)
- Vikas Navratna
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
| | - Savitha Nadig
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
| | - Varun Sood
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
| | - K. Prasad
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
| | - Gayathri Arakere
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
| | - B. Gopal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India, Sir Dorabji Tata Center for Research in Tropical Diseases, Indian Institute of Science Campus, Bangalore 560 012, India
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López-Hernández S, Alarcón T, López-Brea M. Biochemical characterization of chromosomal cephalosporinases from isolates belonging to the Acinetobacter baumannii complex. Clin Microbiol Infect 2001; 7:218-26. [PMID: 11422246 DOI: 10.1046/j.1469-0691.2001.00222.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- S López-Hernández
- Department of Microbiology, Hospital Universitario de la Princesa, Diego de León, 62, 28006 Madrid, Spain.
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13
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Cantón R, Morosini MI, Ballestero S, Alvarez ME, Escobar H, Máiz L, Baquero F. Lung colonization with Enterobacteriaceae producing extended-spectrum beta-lactamases in cystic fibrosis patients. Pediatr Pulmonol 1997; 24:213-7. [PMID: 9330418 DOI: 10.1002/(sici)1099-0496(199709)24:3<213::aid-ppul7>3.0.co;2-n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Cantón
- Department of Microbiology, Ramón y Cajal Hospital, Madrid, Spain
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14
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Thauvin-Eliopoulos C, Tripodi MF, Moellering RC, Eliopoulos GM. Efficacies of piperacillin-tazobactam and cefepime in rats with experimental intra-abdominal abscesses due to an extended-spectrum beta-lactamase-producing strain of Klebsiella pneumoniae. Antimicrob Agents Chemother 1997; 41:1053-7. [PMID: 9145868 PMCID: PMC163849 DOI: 10.1128/aac.41.5.1053] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The in vivo activities of piperacillin-tazobactam and cefepime were compared with those of ticarcillin-clavulanate, ceftazidime, cefotaxime, and imipenem in a rat model of intra-abdominal abscess with a strain of Klebsiella pneumoniae elaborating an extended-spectrum beta-lactamase (TEM-26). With the exception of ceftazidime, all of the antimicrobial agents significantly reduced bacterial counts within abscesses at the end of therapy compared with those in untreated controls. Residual viable cell counts (mean +/- standard deviation in log10 CFU/gram) were as follows: control, 8.76 +/- 0.97; ceftazidime, 8.00 +/- 0.76; piperacillin-tazobactam, 3.87 +/- 1.72; ticarcillin-clavulanate, 3.74 +/- 1.34; cefepime, 3.15 +/- 1.19; cefotaxime, 2.61 +/- 0.77; imipenem, 2.41 +/- 0.93. Imipenem was more effective than either of the inhibitor combinations (P < 0.05). Cefotaxime was unexpectedly effective given its poor in vivo activity against this organism in our earlier studies, which used a different dose and total duration of therapy (L. B. Rice, J. D. C. Yao, K. Klimm, G. M. Eliopoulos, and R. C. Moellering, Jr., Antimicrob. Agents Chemother. 35:1243-1244, 1991). These observations suggest that the effectiveness of cephalosporins in the treatment of experimental infections caused by extended-spectrum beta-lactamase-producing K. pneumoniae may be highly dependent on dosing regimens, even for a specific organism and site of infection.
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Affiliation(s)
- C Thauvin-Eliopoulos
- Department of Medicine, Deaconess Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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15
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Abstract
A predictive modular neural network (PREMONN) architecture for time series classification is presented. The PREMONN has a hierarchical structure. The bottom level consists of a bank of linear or nonlinear predictor modules. The top level is a decision module which employs Bayesian or nonprobabilistic decision rules. For various choices of prediction and decision modules, convergence to correct classification is proven. Also it is shown that PREMONN is robust to noise and the speed/accuracy tradeoff is investigated. The analysis is mainly mathematical; however, we also present classification experiments to corroborate our conclusions. Copyright 1996 Elsevier Science Ltd.
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Petridis V, Kehagias A. Modular neural networks for MAP classification of time series and the partition algorithm. ACTA ACUST UNITED AC 1996; 7:73-86. [DOI: 10.1109/72.478393] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Alonso R, Fernández-Aranguiz A, Colom K, Morla A, Suinaga E, Umaran A, Cisterna R. In vitro activity of biapenem against beta-lactamase producing Enterobacteriaceae. Eur J Clin Microbiol Infect Dis 1994; 13:820-2. [PMID: 7889951 DOI: 10.1007/bf02111342] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The activity of biapenem was compared with that of imipenem and cefotaxime against 108 strains of beta-lactamase producing Enterobacteriaceae. Biapenem and imipenem were very active, inhibiting 90% of the strains at a concentration of 0.5 microgram/ml. Both carbapenems were very active against plasmidic beta-lactamase producers, with MIC90s below 1 microgram/ml. However, the MIC90 of biapenem for cephalosporinase producers was 1 microgram/ml. Against strains producing extended-spectrum beta-lactamases, biapenem exhibited better activity against TEM-type producers (MIC90 0.25 microgram/ml) than against SHV-type producers (MIC90 0.5 microgram/ml). Overall, the in vitro antibacterial activity of biapenem is similar to that of imipenem.
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Affiliation(s)
- R Alonso
- Department of Microbiology, School of Medicine, University of Basque Country, Bilbao, Spain
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Fernandez-Rodriguez A, Canton R, Perez-Diaz JC, Martinez-Beltran J, Picazo JJ, Baquero F. Aminoglycoside-modifying enzymes in clinical isolates harboring extended-spectrum beta-lactamases. Antimicrob Agents Chemother 1992; 36:2536-8. [PMID: 1489200 PMCID: PMC284369 DOI: 10.1128/aac.36.11.2536] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The aminoglycoside-modifying enzymes present in the first 120 clinical isolates harboring extended-spectrum beta-lactamases isolated in Spain were studied. Most of these isolates (84%) were gentamicin resistant. The enzymes most frequently associated and cotransferred with SHV-2 or TEM-type beta-lactamases were AAC(3)V, APH(3"), and APH(3')I.
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Mancini R, Massida O, Satta G. Rate of penetration of cefetamet, cefixime, cefuroxime and cefaclor in different strains of Enterobacteriaceae. Med Mal Infect 1992. [DOI: 10.1016/s0399-077x(05)80867-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Affiliation(s)
- G A Jacoby
- Massachusetts General Hospital, Boston 02114
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21
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Papanicolaou GA, Medeiros AA, Jacoby GA. Novel plasmid-mediated beta-lactamase (MIR-1) conferring resistance to oxyimino- and alpha-methoxy beta-lactams in clinical isolates of Klebsiella pneumoniae. Antimicrob Agents Chemother 1990; 34:2200-9. [PMID: 1963529 PMCID: PMC172023 DOI: 10.1128/aac.34.11.2200] [Citation(s) in RCA: 193] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Klebsiella pneumoniae isolates from 11 patients at the Miriam Hospital were identified as resistant to cefoxitin and ceftibuten as well as to aztreonam, cefotaxime, and ceftazidime. Resistance could be transferred by conjugation or transformation with plasmid DNA into Escherichia coli and was due to the production of a beta-lactamase with an isoelectric point of 8.4 named MIR-1. In E. coli, MIR-1 conferred resistance to aztreonam, cefotaxime, ceftazidime, ceftibuten, ceftriaxone, and such alpha-methoxy beta-lactams as cefmetazole, cefotetan, cefoxitin, and moxalactam. In vitro, MIR-1 hydrolyzed cephalothin and cephaloridine much more rapidly than it did penicillin G, ampicillin, or carbenicillin. Cefotaxime was hydrolyzed at 10% the rate of cephaloridine. Cefoxitin inactivation could only be detected by a microbiological test. The inhibition profile of MIR-1 was similar to that of chromosomally mediated class I beta-lactamases. Potassium clavulanate had little effect on cefoxitin or cefibuten resistance and was a poor inhibitor of MIR-1 activity. Cefoxitin or imipenem did not induce MIR-1. The gene determining MIR-1 was cloned on a 1.4-kb AccI-PstI fragment. Under stringent conditions, probes for TEM-1 and SHV-1 genes and the E. coli ampC gene failed to hybridize with the MIR-1 gene. However, a provisional sequence of 150 bp of the MIR-1 gene proved to be 90% identical to the sequence of ampC from Enterobacter cloacae but only 71% identical to that of E. coli, thus explaining the lack of hybridization to the E. coli ampC probe. Plasmid profiles of the 11 K. pneumoniae clinical isolates were not identical, but each contained a plasmid from 40 to 60 kb that hybridized with the cloned MIR-1 gene. Both transfer-proficient and transfer-deficient MIR-1 plasmids belonged to the N incompatibility group. Thus, the resistance of these K. pneumoniae strains was the result of plasmid acquisition of a class I beta-lactamase, a new resistance determinant that expands the kinds of beta-lactam resistance capable of spread by plasmid dissemination among clinical isolates.
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Affiliation(s)
- G A Papanicolaou
- Division of Infectious Diseases, Miriam Hospital, Providence, Rhode Island 02906
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Rice LB, Willey SH, Papanicolaou GA, Medeiros AA, Eliopoulos GM, Moellering RC, Jacoby GA. Outbreak of ceftazidime resistance caused by extended-spectrum beta-lactamases at a Massachusetts chronic-care facility. Antimicrob Agents Chemother 1990; 34:2193-9. [PMID: 2073110 PMCID: PMC172022 DOI: 10.1128/aac.34.11.2193] [Citation(s) in RCA: 279] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
During a 4-month period in late 1988, we isolated ceftazidime-resistant strains of Klebsiella pneumoniae and other members of the family Enterobacteriaceae from 29 patients at a chronic-care facility in Massachusetts. Ceftazidime resistance resulted from two distinct extended-spectrum beta-lactamases of the TEM type which efficiently hydrolyzed the cephalosporin: YOU-1 with a pI of 5.57 and YOU-2 with a pI of 5.2. Genes encoding these enzymes were present on different but closely related high-molecular-weight, multiple antibiotic resistance plasmids of the H12 incompatibility group and were transferable by conjugation in vitro. Agarose gel electrophoresis of extracts from clinical isolates indicated that this outbreak arose from plasmid transmission among different strains of the family Enterobacteriaceae rather than from dissemination of a single resistant isolate. Isolation rates of ceftazidime-resistant organisms transiently decreased after use of this drug was restricted, but resistant isolates continued to be recovered 7 months after empiric use of ceftazidime ceased.
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Affiliation(s)
- L B Rice
- New England Deaconess Hospital, Boston, Massachusetts 02115
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