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Sato T, Ito R, Kawamura M, Fujimura S. The Risk of Emerging Resistance to Trimethoprim/Sulfamethoxazole in Staphylococcus aureus. Infect Drug Resist 2022; 15:4779-4784. [PMID: 36039323 PMCID: PMC9419895 DOI: 10.2147/idr.s375588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/17/2022] [Indexed: 11/28/2022] Open
Abstract
Objective Due to the spread of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), the demand for trimethoprim/sulfamethoxazole (SXT) is increasing in the world. It is not clear whether the resistant strain emerges by overuse of SXT. We investigated here the emergent risk of the SXT-resistant mutant in S. aureus by an in vitro SXT exposure experiment. Methods A total of 40 S. aureus clinical isolates (20 MSSA and 20 MRSA isolates) were exposed to sub-MIC of SXT for consecutive days, and MIC of SXT was determined every day. In addition, the dfrB DNA sequencing was performed to detect the mutation in the SXT-resistant strain. Results The SXT-resistant strain began to emerge on the eighth day and accounted for 45% (18/40 clinical isolates) after 14 days. Moreover, one half of these resistant strains showed F98Y mutation in DfrB to retain SXT-resistance without selective pressure. Conclusion The emergent risk was SXT exposure of 14 days or more.
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Affiliation(s)
- Takumi Sato
- Division of Clinical Infectious Diseases & Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Ryota Ito
- Division of Clinical Infectious Diseases & Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Masato Kawamura
- Division of Clinical Infectious Diseases & Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Shigeru Fujimura
- Division of Clinical Infectious Diseases & Chemotherapy, Tohoku Medical and Pharmaceutical University, Sendai, Japan
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Tanramluk D, Pakotiprapha D, Phoochaijaroen S, Chantravisut P, Thampradid S, Vanichtanankul J, Narupiyakul L, Akavipat R, Yuvaniyama J. MANORAA: A machine learning platform to guide protein-ligand design by anchors and influential distances. Structure 2021; 30:181-189.e5. [PMID: 34614393 DOI: 10.1016/j.str.2021.09.004] [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: 04/17/2021] [Revised: 06/25/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
The MANORAA platform uses structure-based approaches to provide information on drug design originally derived from mapping tens of thousands of amino acids on a grid. In-depth analyses of the pockets, frequently occurring atoms, influential distances, and active-site boundaries are used for the analysis of active sites. The algorithms derived provide model equations that can predict whether changes in distances, such as contraction or expansion, will result in improved binding affinity. The algorithm is confirmed using kinetic studies of dihydrofolate reductase (DHFR), together with two DHFR-TS crystal structures. Empirical analyses of 881 crystal structures involving 180 ligands are used to interpret protein-ligand binding affinities. MANORAA links to major biological databases for web-based analysis of drug design. The frequency of atoms inside the main protease structures, including those from SARS-CoV-2, shows how the rigid part of the ligand can be used as a probe for molecular design (http://manoraa.org).
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Affiliation(s)
- Duangrudee Tanramluk
- Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand; Integrative Computational BioScience (ICBS) Center, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand.
| | - Danaya Pakotiprapha
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
| | - Sakao Phoochaijaroen
- Integrative Computational BioScience (ICBS) Center, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Pattra Chantravisut
- Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Sirikanya Thampradid
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
| | - Jarunee Vanichtanankul
- National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
| | - Lalita Narupiyakul
- Integrative Computational BioScience (ICBS) Center, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand; Department of Computer Engineering, Faculty of Engineering, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Ruj Akavipat
- Integrative Computational BioScience (ICBS) Center, Mahidol University, Salaya, Nakhon Pathom 73170, Thailand
| | - Jirundon Yuvaniyama
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Ratchathewi, Bangkok 10400, Thailand
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Nagendra Prasad HS, Manukumar HM, Karthik CS, Mallesha L, Mallu P. A novel copper (II) PAmPiCaT complex (cPAmPiCaTc) as a biologically potent candidate: A contraption evidence against methicillin-resistant Staphylococcus aureus (MRSA) and a molecular docking proof. Bioorg Med Chem 2019; 27:841-850. [PMID: 30718062 DOI: 10.1016/j.bmc.2019.01.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 01/23/2023]
Abstract
Increasing in the alarm against the resistant bacteria due to the failure of antibiotics, thereby the need of more efficiency/potent molecule to treat infections. In the present investigation, series of piperazine derivatives 5(a-l) compounds were synthesized and they were characterised by different spectral techniques such as 1H NMR, 13C NMR, IR and LCMS. A novel copper complex (cPAmPiCaTc) was developed for the first time by using potent analog 5e and characterized by IR and LCMS. The cPAmPiCaTc evaluated for antibacterial activity and showed excellent antimicrobial effect (12 ± 0.08 mm, ZOI) at MIC 20 µg/mL against MRSA compared to standard antibiotics streptomycin and bacitracin at MIC 10 µg/mL. The results show promising anti-staphylococcal action against MRSA which confirmed by membrane damage, bioelectrochemistry, gene regulation (SarA and DHFR), and in silico molecular docking studies. Further, the cPAmPiCaTc also showed excellent blood compatibility and this result pave the way for interesting metallodrug therapeutics in future against MRSA infections.
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Affiliation(s)
- H S Nagendra Prasad
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, Mysuru 570 006, Karnataka, India
| | - H M Manukumar
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, Mysuru 570 006, Karnataka, India
| | - C S Karthik
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, Mysuru 570 006, Karnataka, India
| | - L Mallesha
- PG Department of Chemistry, JSS College of Arts, Commerce and Science, Mysuru 570025, Karnataka, India
| | - P Mallu
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, Mysuru 570 006, Karnataka, India.
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4
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Affiliation(s)
- R.L. Then
- Pharmaceutical Research, F. Hoffmann-La Roche Ltd CH-4002 Basel, Switzerland
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5
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Towards the understanding of resistance mechanisms in clinically isolated trimethoprim-resistant, methicillin-resistant Staphylococcus aureus dihydrofolate reductase. J Struct Biol 2009; 170:93-7. [PMID: 20026215 DOI: 10.1016/j.jsb.2009.12.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 12/07/2009] [Accepted: 12/14/2009] [Indexed: 11/20/2022]
Abstract
Resistance to therapeutics such as trimethoprim-sulfamethoxazole has become an increasing problem in strains of methicillin-resistant Staphylococcus aureus (MRSA). Clinically isolated trimethoprim-resistant strains reveal a double mutation, H30N/F98Y, in dihydrofolate reductase (DHFR). In order to develop novel and effective therapeutics against these resistant strains, we evaluated a series of propargyl-linked antifolate lead compounds for inhibition of the mutant enzyme. For the propargyl-linked antifolates, the F98Y mutation generates minimal (between 1.2- and 6-fold) losses of affinity and the H30N mutation generates greater losses (between 2.4- and 48-fold). Conversely, trimethoprim affinity is largely diminished by the F98Y mutation (36-fold) and is not affected by the H30N mutation. In order to elucidate a mechanism of resistance, we determined a crystal structure of a complex of this double mutant with a lead propargyl-linked antifolate. This structure suggests a resistance mechanism consistent both for the propargyl-linked class of antifolates and for trimethoprim that is based on the loss of a conserved water-mediated hydrogen bond.
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6
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Heaslet H, Harris M, Fahnoe K, Sarver R, Putz H, Chang J, Subramanyam C, Barreiro G, Miller JR. Structural comparison of chromosomal and exogenous dihydrofolate reductase from Staphylococcus aureus in complex with the potent inhibitor trimethoprim. Proteins 2009; 76:706-17. [PMID: 19280600 DOI: 10.1002/prot.22383] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dihydrofolate reductase (DHFR) is the enzyme responsible for the NADPH-dependent reduction of 5,6-dihydrofolate to 5,6,7,8-tetrahydrofolate, an essential cofactor in the synthesis of purines, thymidylate, methionine, and other key metabolites. Because of its importance in multiple cellular functions, DHFR has been the subject of much research targeting the enzyme with anticancer, antibacterial, and antimicrobial agents. Clinically used compounds targeting DHFR include methotrexate for the treatment of cancer and diaminopyrimidines (DAPs) such as trimethoprim (TMP) for the treatment of bacterial infections. DAP inhibitors of DHFR have been used clinically for >30 years and resistance to these agents has become widespread. Methicillin-resistant Staphylococcus aureus (MRSA), the causative agent of many serious nosocomial and community acquired infections, and other gram-positive organisms can show resistance to DAPs through mutation of the chromosomal gene or acquisition of an alternative DHFR termed "S1 DHFR." To develop new therapies for health threats such as MRSA, it is important to understand the molecular basis of DAP resistance. Here, we report the crystal structure of the wild-type chromosomal DHFR from S. aureus in complex with NADPH and TMP. We have also solved the structure of the exogenous, TMP resistant S1 DHFR, apo and in complex with TMP. The structural and thermodynamic data point to important molecular differences between the two enzymes that lead to dramatically reduced affinity of DAPs to S1 DHFR. These differences in enzyme binding affinity translate into reduced antibacterial activity against strains of S. aureus that express S1 DHFR.
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Affiliation(s)
- Holly Heaslet
- Lead Development Technologies, Pfizer Global Research and Development, Groton, Connecticut 06340, USA.
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7
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Antistaphylococcal activity of dihydrophthalazine antifolates, a family of novel antibacterial drugs. Antimicrob Agents Chemother 2009; 53:1353-61. [PMID: 19188385 DOI: 10.1128/aac.01619-08] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For a panel of 153 Staphylococcus aureus clinical isolates (including 13 vancomycin-intermediate or heterogeneous vancomycin-intermediate and 4 vancomycin-resistant strains), MIC(50)s and MIC(90)s of three novel dihydrophthalazine antifolates, BAL0030543, BAL0030544, and BAL0030545, were 0.03 and 0.25 microg/ml, respectively, for methicillin-susceptible strains and 0.03 and <or=0.25 microg/ml, respectively, for methicillin-resistant strains. For a panel of 160 coagulase-negative staphylococci (including 5 vancomycin-intermediate and heterogeneous vancomycin-intermediate strains and 7 linezolid-nonsusceptible strains), MIC(50)s and MIC(90)s were <or=0.03 and <or=0.06 microg/ml, respectively, for methicillin-susceptible strains and 0.06 and 0.5 microg/ml, respectively, for methicillin-resistant strains. Vancomycin was active against 93.0% of 313 staphylococci examined; linezolid was active against all S. aureus strains and 95.6% of coagulase-negative staphylococcus strains, whereas elevated MICs of clindamycin, minocycline, trimethoprim, and rifampin for some strains were observed. At 4x MIC, the dihydrophthalazines were bactericidal against 11 of 12 staphylococcal strains surveyed. The prolonged serial passage of some staphylococcal strains in the presence of subinhibitory concentrations of BAL0030543, BAL0030544, and BAL0030545 produced clones for which dihydrophthalazines showed high MICs (>128 microg/ml), although rates of endogenous resistance development were much lower for the dihydrophthalazines than for trimethoprim. Single-step platings of naïve staphylococci onto media containing dihydrophthalazine antifolates indicated considerable variability among strains with respect to preexistent subpopulations nonsusceptible to dihydrophthalazine antifolates.
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8
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Barrow EW, Dreier J, Reinelt S, Bourne PC, Barrow WW. In vitro efficacy of new antifolates against trimethoprim-resistant Bacillus anthracis. Antimicrob Agents Chemother 2007; 51:4447-52. [PMID: 17875993 PMCID: PMC2167980 DOI: 10.1128/aac.00628-07] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis is innately resistant to trimethoprim (TMP), a synthetic antifolate that selectively inhibits several bacterial dihydrofolate reductases (DHFRs) but not human DHFR. Previously, we were able to confirm that TMP resistance in B. anthracis (MIC > 2,048 microg/ml) is due to the lack of selectivity of TMP for the B. anthracis DHFR (E. W. Barrow, P. C. Bourne, and W. W. Barrow, Antimicrob. Agents Chemother. 48:4643-4649, 2004). In this investigation, 24 2,4-diaminopyrimidine derivatives, representing a class of compounds with dihydrophthalazine side chains, were screened for their in vitro effects on B. anthracis Sterne and their selectivities for the B. anthracis DHFR. MICs were obtained by a colorimetric (Alamar blue) broth microdilution assay. Purified human recombinant DHFR (rDHFR) and B. anthracis rDHFR were used in a validated enzyme assay to determine the 50% inhibitory concentrations (IC(50)s) and the selectivity ratios of the derivatives. The MICs ranged from 12.8 to 128 microg/ml for all but nine compounds, for which the MICs were > or =128 microg/ml. The IC(50) values for B. anthracis rDHFR ranged from 46 to 600 nM, whereas the IC(50) values for human rDHFR were >16,000 nM. This is the first report on the in vitro inhibitory actions of this class of antifolates against TMP-resistant B. anthracis isolates. The selective inhibition of B. anthracis rDHFR and the in vitro activity against B. anthracis demonstrate that members of this class of compounds have the potential to be developed into clinically important therapeutic choices for the treatment of infections caused by TMP-resistant bacteria, such as B. anthracis.
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Affiliation(s)
- Esther W Barrow
- Department of Veterinary Pathobiology, 250 McElroy, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA
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9
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Qi W, Ender M, O'Brien F, Imhof A, Ruef C, McCallum N, Berger-Bächi B. Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Zurich, Switzerland (2003): prevalence of type IV SCCmec and a new SCCmec element associated with isolates from intravenous drug users. J Clin Microbiol 2005; 43:5164-70. [PMID: 16207979 PMCID: PMC1248496 DOI: 10.1128/jcm.43.10.5164-5170.2005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The majority of methicillin-resistant Staphylococcus aureus (MRSA) isolates, recovered in 2003 at the Department of Medical Microbiology in Zürich, Switzerland, belonged to major clones that are circulating worldwide. Staphylococcal cassette chromosome mec type IV (SCCmec-IV), harbored by half of the isolates, was found in sequence type 217 (ST 217), which is an allelic variant of epidemic MRSA-15 (designated EMRSA-15), in a new local ST 617 descending from clonal complex CC 8 and in low-level oxacillin-resistant strains of multiple genetic lineages characteristic of community-onset MRSA. SCCmec-I, SCCmec-II, and SCCmec-III were in the minority, and four MRSA isolates had complex, rearranged SCCmec elements. A novel SCCmec-N1 of approximately 30 kb, associated with a dfrA gene and a ccr 4-related recombinase complex, was identified in a large number of low-level oxacillin-resistant isolates, which descended from the successful clonal complex CC 45 and are spreading among intraveneous drug users. In contrast, the SCCmec types of oxacillin-resistant coagulase-negative staphylococci (MRCNS) were of completely different composition. SCCmec type I (SCCmec-I) and SCCmec-II were more frequent than in the MRSA, while fewer contained SCCmec-IV. The other MRCNS displayed 11 different, complex patterns, suggesting frequent recombination between different SCCmec elements. With one ccr-negative exception, these strains amplified between one and three different ccr products, indicating either new varied complexes or multiple ccr loci. This suggests the presence of novel SCCmec types in MRCNS and no extensive interspecies SCCmec transfer between MRSA and MRCNS.
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Affiliation(s)
- Wei Qi
- Department of Medical Microbiology, University of Zürich, CH-8006 Zürich, Switzerland
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10
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Sekiguchi JI, Tharavichitkul P, Miyoshi-Akiyama T, Chupia V, Fujino T, Araake M, Irie A, Morita K, Kuratsuji T, Kirikae T. Cloning and characterization of a novel trimethoprim-resistant dihydrofolate reductase from a nosocomial isolate of Staphylococcus aureus CM.S2 (IMCJ1454). Antimicrob Agents Chemother 2005; 49:3948-51. [PMID: 16127079 PMCID: PMC1195413 DOI: 10.1128/aac.49.9.3948-3951.2005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel gene, dfrG, encoding a trimethoprim (TMP)-resistant dihydrofolate reductase (DHFR, designated S3DHFR) was cloned from a clinical isolate of methicillin-resistant Staphylococcus aureus. Escherichia coli expressing dfrG was highly resistant to TMP. Recombinant S3DHFR exhibited DHFR activity that was not inhibited by TMP.
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Affiliation(s)
- Jun-ichiro Sekiguchi
- Department of Infectious Diseases, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku, Tokyo 162-8655, Japan
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11
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Totake K, Kobayashi N, Odaka T. Trimethoprim resistance and susceptibility genes in Staphylococcus epidermidis. Microbiol Immunol 1998; 42:497-501. [PMID: 9719102 DOI: 10.1111/j.1348-0421.1998.tb02315.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Genes encoding trimethoprim (TMP)-resistant and -susceptible dihydrofolate reductases (DHFR) in Staphylococcus epidermidis isolated in Saitama Prefecture were compared with the TMP-resistant DHFR gene of S. aureus, dfrA. The nucleotide sequences of TMPr and TMPs genes in five S. epidermidis isolates tested could be divided into three types: type 1, identical with the TMPr gene dfrA that had been found in S. aureus; type 3, identical with the TMPs gene dfrC in S. epidermidis; and type 2, having only two nucleotide substitutions to dfrC with no amino acid change. TMPr isolates carried either one of the type 2 or type 3 sequences in addition to the type 1 sequence. A Southern hybridization analysis revealed that, in TMPr S. epidermidis, the type 1 sequence was located on a 5.5 kb EcoRI-EcoRV restriction fragment together with the sequence for the gentamicin (GM)-resistant gene, while the type 2 or type 3 sequence was located on the 1.0 kb EcoRI-EcoRV fragment. No plasmid-carrying dfrA-homologous sequence was detected in the S. epidermidis isolates we tested. These results suggest that the TMPr and GMr genes are closely linked and located on the chromosome in S. epidermidis isolated in Japan.
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Affiliation(s)
- K Totake
- Department of Microbiology, Saitama Medical School, Japan.
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12
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Maranan MC, Moreira B, Boyle-Vavra S, Daum RS. Antimicrobial resistance in staphylococci. Epidemiology, molecular mechanisms, and clinical relevance. Infect Dis Clin North Am 1997; 11:813-49. [PMID: 9421702 DOI: 10.1016/s0891-5520(05)70392-5] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Staphylococcal infections continue to pose important clinical problems in children and adults. Antibiotic resistance among the staphylococci has rendered therapy of these infections a therapeutic challenge. Despite early, uniform susceptibility to penicillin, staphylococci acquired a gene elaborating beta-lactamase that rendered penicillin inactive and that is borne by nearly all clinical isolates. "Penicillinase-resistant beta-lactams," such as methicillin, were introduced in the early 1960s, but resistance to them has become an increasing concern. The mechanism of the so-called "methicillin resistance" is complex. Moreover, once confined to the ecology of hospitals and other institutions, a recent increase in community-acquired methicillin-resistant S. aureus infections has been observed. Glycopeptides, until now the only uniformly reliable therapeutic modality, have been increasingly used for therapy of staphylococcal infections. The recent recognition of clinical isolates with reduced susceptibility to glycopeptides is of concern.
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Affiliation(s)
- M C Maranan
- Department of Pediatrics, University of Chicago, Illinois, USA
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13
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Adrian PV, Klugman KP. Mutations in the dihydrofolate reductase gene of trimethoprim-resistant isolates of Streptococcus pneumoniae. Antimicrob Agents Chemother 1997; 41:2406-13. [PMID: 9371341 PMCID: PMC164136 DOI: 10.1128/aac.41.11.2406] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus pneumoniae isolates resistant to several antimicrobial agent classes including trimethoprim-sulfamethoxazole have been reported with increasing frequency throughout the world. The MICs of trimethoprim, sulfamethoxazole, and trimethoprim-sulfamethoxazole (1:19) for 259 clinical isolates from South Africa were determined, and 166 of these 259 (64%) isolates were resistant to trimethoprim-sulfamethoxazole (MICs > or =20 mg/liter). Trimethoprim resistance was found to be more strongly correlated with trimethoprim-sulfamethoxazole resistance (correlation coefficient, 0.744) than was sulfamethoxazole resistance (correlation coefficient, 0.441). The dihydrofolate reductase genes from 11 trimethoprim-resistant (MICs, 64 to 512 microg/ml) clinical isolates of Streptococcus pneumoniae were amplified by PCR, and the nucleotide sequences were determined. Two main groups of mutations to the dihydrofolate reductase gene were found. Both groups shared six amino acid changes (Glu20-Asp, Pro70-Ser, Gln81-His, Asp92-Ala, Ile100-Leu, and Leu135-Phe). The first group included two extra changes (Lys60-Gln and Pro111-Ser), and the second group was characterized by six additional amino acid changes (Glu14-Asp, Ile74-Leu, Gln91-His, Glu94-Asp, Phe147-Ser, and Ala149-Thr). Chromosomal DNA from resistant isolates and cloned PCR products of the genes encoding resistant dihydrofolate reductases were capable of transforming a susceptible strain of S. pneumoniae to trimethoprim resistance. The inhibitor profiles of recombinant dihydrofolate reductase from resistant and susceptible isolates revealed that the dihydrofolate reductase from trimethoprim-resistant isolates was 50-fold more resistant (50% inhibitory doses [ID50s], 3.9 to 7.3 microM) than that from susceptible strains (ID50s, 0.15 microM). Site-directed mutagenesis experiments revealed that one mutation, Ile100-Leu, resulted in a 50-fold increase in the ID50 of trimethoprim. The resistant dihydrofolate reductases were characterized by highly conserved redundant changes in the nucleotide sequence, suggesting that the genes encoding resistant dihydrofolate reductases may have evolved as a result of inter- or intraspecies recombination by transformation.
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Affiliation(s)
- P V Adrian
- Pneumococcal Diseases Research Unit of South African Institute for Medical Research, University of the Witwatersrand, and Medical Research Council, Johannesburg.
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14
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Dale GE, Broger C, D'Arcy A, Hartman PG, DeHoogt R, Jolidon S, Kompis I, Labhardt AM, Langen H, Locher H, Page MG, Stüber D, Then RL, Wipf B, Oefner C. A single amino acid substitution in Staphylococcus aureus dihydrofolate reductase determines trimethoprim resistance. J Mol Biol 1997; 266:23-30. [PMID: 9054967 DOI: 10.1006/jmbi.1996.0770] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A single amino acid substitution, Phe98 to Tyr98, in dihydrofolate reductase (DHFR) is the molecular origin of trimethoprim (TMP) resistance in Staphylococcus aureus. This active site amino acid substitution was found in all S. aureus TMP-resistant clinical isolates tested. In order to explore the structural role of Tyr98 in TMP-resistance the ternary complexes of the chromosomal S. aureus DHFR (SaDHFR) with methotrexate (MTX) and TMP in the presence of nicotinamide adenine dinucleotide phosphate (NADPH) as well as that of mutant Phe98Tyr DHFR SaDHFR(F98Y) ternary folate-NADPH complex have been determined by X-ray crystallography. Critical evidence concerning the resistance mechanism has also been provided by NMR spectral analyses of 15N-labelled TMP in the ternary complexes of both wild-type and mutant enzyme. These studies show that the mutation results in loss of a hydrogen bond between the 4-amino group of TMP and the carbonyl oxygen of Leu5. This mechanism of resistance is predominant in both transferable plasmid-encoded and non-transferable chromosomally encoded resistance. Knowledge of the resistance mechanism at a molecular level could help in the design of antibacterials active against multi-resistant Staphylococcus aureus (MRSA), one of todays most serious problems in clinical infectology.
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Affiliation(s)
- G E Dale
- F. Hoffmann-La Roche Ltd, Pharma Preclinical Research Department, Basel, Switzerland
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15
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Levine A, Vannier F, Roche B, Autret S, Mavel D, Sror SJ. A 10.3 kbp segment from nprB to argJ at the 102 degrees region of the Bacillus subtilis chromosome. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 1):175-177. [PMID: 9025291 DOI: 10.1099/00221287-143-1-175] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The approximately 10 kbp region encompassing nprB and argJ at 102 degrees on the Bacillus subtilis chromosome was sequenced, revealing 12 ORFs, four known genes (argJ, argC, ipi and nprB) and two genes, yitY and yitS, whose products respectively display significant homology with L-gulono-gamma-lactone oxidase of rat and dihydrofolate reductase of Staphylococcus aureus. The data also indicated that nprB mapped to a different position than previously published.
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Affiliation(s)
- A Levine
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
| | - F Vannier
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
| | - B Roche
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
| | - S Autret
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
| | - D Mavel
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
| | - S J Sror
- Institut de Gntique et Microbiologie URA CNRS 1354, Universit Paris XI, Btiment 409, 91405 Orsay Cedex France
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16
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Dale GE, Langen H, Page MG, Then RL, Stüber D. Cloning and characterization of a novel, plasmid-encoded trimethoprim-resistant dihydrofolate reductase from Staphylococcus haemolyticus MUR313. Antimicrob Agents Chemother 1995; 39:1920-4. [PMID: 8540692 PMCID: PMC162857 DOI: 10.1128/aac.39.9.1920] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In recent years resistance to the antibacterial agent trimethoprim (Tmp) has become more widespread, and several trimethoprim-resistant (Tmpr) dihydrofolate reductases (DHFRs) have been described from gram-negative bacteria. In staphylococci, only one Tmpr DHFR has been described, the type S1 DHFR, which is encoded by the dfrA gene found on transposon Tn4003. In order to investigate the coincidence of high-level Tmp resistance and the presence of dfrA, we analyzed the DNAs from various Tmpr staphylococci for the presence of dfrA sequences by PCR with primers specific for the thyE-dfrA genes from Tn4003. We found that 30 or 33 isolates highly resistant to Tmp (MICs, > or = 512 micrograms/ml) contained dfrA sequences, whereas among the Tmpr (MICs, < or = 256 micrograms/ml) and Tmps isolates only the Staphylococcus epidermidis isolates (both Tmpr and Tmps) seemed to contain the dfrA gene. Furthermore, we have cloned and characterized a novel, plasmid-encoded Tmpr DHFR from Staphylococcus haemolyticus MUR313. The dfrD gene of plasmid pABU17 is preceded by two putative Shine-Dalgarno sequences potentially allowing for the start of translation at two triplets separated by nine nucleotides. The predicted protein of 166 amino acids, designated S2DHFR, encoded by the longer open reading frame was overproduced in Escherichia coli, purified, and characterized. The molecular size of the recombinant S2DHFR was determined by ion spray mass spectrometry to be 19,821.2 +/- 2 Da, which is in agreement with the theoretical value of 19,822 Da. In addition, the recombinant S2DHFR was shown to exhibit DHFR activity and to be highly resistant to Tmp.
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Affiliation(s)
- G E Dale
- Department of Gene Technologies, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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Abstract
Staphylococci have developed a variety of strategies for dealing with the presence of antibiotics encountered in clinical environments. Resistance to beta-lactams and other antimicrobial agents has been accomplished by a diverse array of molecular mechanisms. Options available to treat infections caused by staphylococci resistant to methicillin are limited, and the next generation of antibiotics to be introduced, should glycopeptide resistance become an important clinical problem, is not yet on the horizon.
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Affiliation(s)
- B M Moreira
- Department of Pediatrics, University of Chicago, Illinois, USA
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Dale GE, Broger C, Hartman PG, Langen H, Page MG, Then RL, Stüber D. Characterization of the gene for the chromosomal dihydrofolate reductase (DHFR) of Staphylococcus epidermidis ATCC 14990: the origin of the trimethoprim-resistant S1 DHFR from Staphylococcus aureus? J Bacteriol 1995; 177:2965-70. [PMID: 7768789 PMCID: PMC176980 DOI: 10.1128/jb.177.11.2965-2970.1995] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The gene for the chromosomally encoded dihydrofolate reductase (DHFR) of Staphylococcus epidermidis ATCC 14990 has been cloned and characterized. The structural gene encodes a polypeptide of 161 amino acid residues with a calculated molecular weight of 18,417. This trimethoprim-sensitive (Tmps) DHFR, SeDHFR, differs in only three amino acids (Val-31-->Ile, Gly-43-->Ala, and Phe-98-->Tyr) from the trimethoprim-resistant (Tmpr) S1 DHFR encoded by transposon Tn4003. Since in addition the S. epidermidis gene also forms part of an operon with thyE and open reading frame 140 as in Tn4003, the chromosomally located gene encoding the Tmps SeDHFR is likely to be the molecular origin of the plasmid-located gene encoding the Tmpr S1 DHFR. Site-directed mutagenesis and kinetic analysis of the purified enzymes suggest that a single Phe-->Tyr change at position 98 is the major determinant of trimethoprim resistance.
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Affiliation(s)
- G E Dale
- Department of Gene Technologies, F. Hoffmann-La Roche Ltd., Basel, Switzerland
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Bunny KL, Hall RM, Stokes HW. New mobile gene cassettes containing an aminoglycoside resistance gene, aacA7, and a chloramphenicol resistance gene, catB3, in an integron in pBWH301. Antimicrob Agents Chemother 1995; 39:686-93. [PMID: 7793874 PMCID: PMC162606 DOI: 10.1128/aac.39.3.686] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The multidrug resistance plasmid pBWH301 was shown to contain a sull-associated integron with five inserted gene cassettes, aacA7-catB3-aadB-oxa2-orfD, all of which can be mobilized by the integron-encoded DNA integrase. The aadB, oxa2, and orfD cassettes are identical to known cassettes. The aacA7 gene encodes a protein that is a member of one of the three known families of aminoglycoside acetyltransferases classified as AAC(6')-I. The chloramphenicol acetyltransferase encoded by the catB3 gene is closely related to members of a recently identified family of chloramphenicol acetyltransferases. The catB3 gene displays a relatively high degree of sequence identity to a chromosomally located open reading frame in Pseudomonas aeruginosa, and this may represent evidence for the acquisition by a cassette of a chromosomal gene.
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Affiliation(s)
- K L Bunny
- School of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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Huovinen P, Sundström L, Swedberg G, Sköld O. Trimethoprim and sulfonamide resistance. Antimicrob Agents Chemother 1995; 39:279-89. [PMID: 7726483 PMCID: PMC162528 DOI: 10.1128/aac.39.2.279] [Citation(s) in RCA: 300] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- P Huovinen
- Antimicrobial Research Laboratory, National Public Health Institute, Turku, Finland
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Leszczyńska K, Bolhuis A, Leenhouts K, Venema G, Cegłowski P. Cloning and molecular analysis of the dihydrofolate reductase gene from Lactococcus lactis. Appl Environ Microbiol 1995; 61:561-6. [PMID: 7574597 PMCID: PMC167319 DOI: 10.1128/aem.61.2.561-566.1995] [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: 01/26/2023] Open
Abstract
The Lactococcus lactis gene encoding trimethoprim resistance has been cloned and expressed in Escherichia coli and Bacillus subtilis. Several lines of evidence indicate that the cloned gene encodes dihydrofolate reductase (DHFR). (i) It fully complements the fol "null" mutation in E. coli. (ii) Nucleotide sequencing of the cloned fragment revealed the presence of one open reading frame encoding a protein that shares homology with the family of bacterial DHFR enzymes. (iii) Overexpression of this open reading frame in E. coli resulted in the appearance in cell extracts of a protein of the expected size as well as in a dramatic increase of DHFR activity. In cell extracts, the DHFR activity was not inhibited by low trimethoprim concentration. By Northern (RNA) blotting and primer extension analyses, the size and the start point of the dhfr transcript, respectively, have been determined. Results of these experiments indicate that in L. lactis the dhfr gene represents part of a larger transcription unit.
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Affiliation(s)
- K Leszczyńska
- Institute of Biochemistry and Biophysics, Warsaw, Poland
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Leelaporn A, Firth N, Byrne ME, Roper E, Skurray RA. Possible role of insertion sequence IS257 in dissemination and expression of high- and low-level trimethoprim resistance in staphylococci. Antimicrob Agents Chemother 1994; 38:2238-44. [PMID: 7840551 PMCID: PMC284724 DOI: 10.1128/aac.38.10.2238] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The transposon-like structure Tn4003 and related elements were found to encode high- and low-level trimethoprim resistance (Tpr) in Staphylococcus aureus and coagulase-negative staphylococci. By using transcriptional fusions in Escherichia coli, the variation in resistance levels was found to correlate with the transcriptional activity of the region presumed to carry the promoter for the operon containing the Tpr dihydrofolate reductase gene, dfrA, encoded by these elements. The reduced transcriptional activities exhibited by elements encoding low-level Tpr appear to be a consequence of deletions adjacent to the copy of IS257 which normally encodes the -35 sequences of these promoters. The data obtained not only support the involvement of IS257 in the transcription of the proposed thyE-dfrA-orf-140 operon of Tn4003 but may also implicate this insertion sequence in the mechanisms resulting in the variation in Tpr levels observed in staphylococci.
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Affiliation(s)
- A Leelaporn
- School of Biological Sciences, University of Sydney, New South Wales, Australia
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