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Savas S, Hazirolan G, Karagoz A, Parlak M. From days to hours: Can MALDI-TOF MS system replace both conventional and molecular typing methods with new cut off level for Vancomycin Resistant Enterococcus faecium. J Microbiol Methods 2018; 162:62-68. [PMID: 30605699 DOI: 10.1016/j.mimet.2018.12.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 12/11/2018] [Accepted: 12/17/2018] [Indexed: 01/21/2023]
Abstract
Vancomycin-Resistant E. faecium (VRE) strains from clinical specimens were identified by conventional methods before. Following the phenotype-based identification, all strains were also identified using both BD Phoenix and VITEK MS bioMérieux System. Strains were typed with the Bruker MALDI-TOF MS system, pulsed field gel electrophoresis (PFGE) and 16S rRNA gene sequencing analysis and then the sensitivity compared for each. A cut off value of 850 assigned with Bruker MALDI-TOF MS system was found to give equal sensitivity to that of PFGE. Results obtained were compared with those of molecular typing. The main advantage of MALDI-TOF MS technology over the others was the much shorter analysis time which lasted only a few hours rather than days or a whole week. Also, the Bruker MALDI-TOF MS system was used for typing and compared with the gold standard method and this study is first to report the determined cut off level for typing of VRE strains.
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Affiliation(s)
- Sumeyra Savas
- The Scientific and Technological Research Council of Turkey, Kocaeli, Turkey.
| | - Gulsen Hazirolan
- Department of Medical Microbiology, Hacettepe University School of Medicine, Ankara, Turkey
| | | | - Mehmet Parlak
- Department of Medical Microbiology, Yuzuncu Yil University School of Medicine, Ankara, Turkey
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Wang Y, Li X, Jiang L, Han W, Xie X, Jin Y, He X, Wu R. Novel Mutation Sites in the Development of Vancomycin- Intermediate Resistance in Staphylococcus aureus. Front Microbiol 2017; 7:2163. [PMID: 28119680 PMCID: PMC5222870 DOI: 10.3389/fmicb.2016.02163] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 12/22/2016] [Indexed: 11/13/2022] Open
Abstract
Increased use of vancomycin has led to the emergence of vancomycin-intermediate Staphylococcus aureus (VISA). To investigate the mechanism of VISA development, 39 methicillin-susceptible strains and 3 MRSA strains were treated with vancomycin to induce non-susceptibility, and mutations in six genes were analyzed. All the strains were treated with vancomycin in vitro for 60 days. MICs were determined by the agar dilution and E-test methods. Vancomycin was then removed to assess the stability of VISA strains and mutations. Following 60 days of vancomycin treatment in vitro, 29/42 VISA strains were generated. The complete sequences of rpoB, vraS, graR, graS, walK, and walR were compared with those in the parental strains. Seven missense mutations including four novel mutations (L466S in rpoB, R232K in graS, I594M in walk, and A111T in walR) were detected frequently in strains with vancomycin MIC ≥ 12 μg/mL. Jonckheere-Terpstra trend test indicated these mutations might play an important role during VISA evolution. After the vancomycin treatment, strains were passaged to vancomycin-free medium for another 60 days, and the MICs of all strains decreased. Our results suggest that rpoB, graS, walk, and walR are more important than vraS and graR in VISA development.
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Affiliation(s)
- Yubing Wang
- College of Biological Sciences and Biotechnology, Beijing Forestry University Beijing, China
| | - Xiaoli Li
- College of Biological Sciences and Biotechnology, Beijing Forestry University Beijing, China
| | - Libo Jiang
- College of Biological Sciences and Biotechnology, Beijing Forestry UniversityBeijing, China; Center for Computational Biology, Beijing Forestry UniversityBeijing, China
| | - Wentao Han
- College of Biological Sciences and Biotechnology, Beijing Forestry University Beijing, China
| | - Xiangming Xie
- College of Biological Sciences and Biotechnology, Beijing Forestry University Beijing, China
| | - Yi Jin
- College of Biological Sciences and Biotechnology, Beijing Forestry UniversityBeijing, China; Center for Computational Biology, Beijing Forestry UniversityBeijing, China
| | - Xiaoqing He
- College of Biological Sciences and Biotechnology, Beijing Forestry UniversityBeijing, China; Center for Computational Biology, Beijing Forestry UniversityBeijing, China
| | - Rongling Wu
- College of Biological Sciences and Biotechnology, Beijing Forestry UniversityBeijing, China; Center for Computational Biology, Beijing Forestry UniversityBeijing, China; Center for Statistical Genetics, Pennsylvania State UniversityHershey, PA, USA
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Hegde SS, Janc JW. Efficacy of telavancin, a lipoglycopeptide antibiotic, in experimental models of Gram-positive infection. Expert Rev Anti Infect Ther 2014; 12:1463-75. [DOI: 10.1586/14787210.2014.979789] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chambers HF, Hegde SS. Combating the growing problem of methicillin-resistantStaphylococcus aureus: do the newer antibiotics represent a better alternative to vancomycin? Expert Rev Anti Infect Ther 2014; 5:333-5. [PMID: 17547497 DOI: 10.1586/14787210.5.3.333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yoo JI, Kim JW, Kang GS, Kim HS, Yoo JS, Lee YS. Prevalence of amino acid changes in the yvqF, vraSR, graSR, and tcaRAB genes from vancomycin intermediate resistant Staphylococcus aureus. J Microbiol 2013; 51:160-5. [PMID: 23625215 DOI: 10.1007/s12275-013-3088-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 03/21/2013] [Indexed: 11/29/2022]
Abstract
Vancomycin intermediate Staphylococcus aureus (VISA) strains are increasingly prevalent in the hospital setting, and are of major concern in the treatment of methicillin-resistant S. aureus infections. Multiple mutations in vancomycin-susceptible S. aureus (VSSA) strains likely led to the emergence of VISA, and point mutations in the agr, orf1, yvqF, vraSR, graSR, and tcaRAB genes of VISA strains have been shown to contribute to glycopeptide resistance. Therefore, we investigated point mutations in these genes from 87 VISA and 27 VSSA clinical strains isolated from Korean hospitals. All strains were assigned an agr type (I, II, or III) on the basis of multiplex PCR, with the majority of VISA strains belonging to agr groups I and II. Sequencing revealed amino acid changes in vraS from VISA strains which were not present in the VSSA strains. The E59D substitution in the vraR gene occurred in 36.3% of VSSA/agrI and 92.7% of VISA/agrI strains, suggesting that this mutation associated with emergence of VISA/agrI strains. VISA strains were classified into 31 mutation patterns according to mutations in the yvqF, vraSR, graSR, and tcaRAB genes. In addition, the mutation patterns were correlated with agr and sequence type (ST). The most prevalent pattern included agr type I (ST 72) strains with E59D (vraR), L26F and T224I (graS), D148Q (graR), and L218P, R283H and G312D (tcaA) amino acid substitutions. The minimum inhibitory concentration (MIC) range of mutation pattern 5 toward oxacillin and imipenem was much lower than that of patterns 6 and 24. These results improve our understanding of emergence of VISA strains.
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Affiliation(s)
- Jae Il Yoo
- Division of Antimicrobial Resistance, Center for Infectious Diseases, Korea National Institute of Health, Osong 363-951, Republic of Korea
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Selection of heterogeneous vancomycin-intermediate Staphylococcus aureus by imipenem. Antimicrob Agents Chemother 2009; 53:3190-6. [PMID: 19451283 DOI: 10.1128/aac.00834-08] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vancomycin (VAN)-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) isolates are considered to have emerged from VAN-susceptible S. aureus (VSSA) by spontaneous mutation during VAN exposure. We previously reported that laboratory mutant H14, obtained from VSSA strain Delta IP by exposure to imipenem (IPM), showed overexpression of the vraSR two-component system and a typical hVISA phenotype. In the present study, to elucidate the mechanism of VSSA conversion to hVISA, we further characterized strain H14 by determining its whole-genome sequence, morphology, cell wall synthetic activity, and gene expression. Genome sequencing revealed that H14 harbored a mutated vraS (designated vraS(H14)) that caused an amino acid substitution (S(329)-->L). This mutation is different from the VraS mutation (N(5)-->I) identified in representative clinical hVISA strain Mu3. However, H14 exhibited a phenotype similar to that of Mu3, including heterogeneous resistance to VAN, enhanced cell wall synthetic activity, and vraSR overexpression. Replacement of the vraS gene of DeltaIP with the mutated vraS(H14) gene confirmed that the S(329)-->L substitution was responsible for both the upregulation of vraSR and conversion to the hVISA phenotype. This conversion was also achieved by using the vraS gene of Mu3, which carries a mutation (N(5)-->I), but not with the native vraS gene of strain N315. Finally, we carried out a study to analyze the appearance of hVISA from VSSA by exposure of Delta IP to selective concentrations of VAN and beta-lactam antibiotics. A total of 8 and 5 hVISA isolates were detected among 50 isolates selected with VAN and IPM, respectively. Among the 13 hVISA mutants, mutation in vraSR was detected only in mutant strain H14, suggesting that additional mutational mechanisms can be responsible for evolution to the hVISA phenotype. We conclude that exposure not only to VAN but also to beta-lactams may select for reduced glycopeptide susceptibility in S. aureus.
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Morgan A, Cofer C, Stevens DL. Iclaprim: a novel dihydrofolate reductase inhibitor for skin and soft tissue infections. Future Microbiol 2009; 4:131-44. [DOI: 10.2217/17460913.4.2.131] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Antibiotic resistance is an ever-increasing concern in the treatment of severe skin and skin-structure infections, pneumonia, bacteremia and other serious infections caused by methicillin-resistant Staphylococcus aureus, vancomycin-resistant S. aureus, group A Streptococcus and vancomycin-resistant Enterococcus. In this review, we summarize the current status of both US FDA-approved and investigational agents aimed at this group of pathogens. We also describe, in detail, the chemistry, mechanism of action, pharmacokinetic properties and spectrum of microbiological activity of iclaprim, a novel dihydrofolate reductase inhibitor recently awarded fast-track approval status by the FDA. Finally, we review the clinical efficacy of iclaprim compared with linezolid for skin and skin-structure infections as demonstrated in Phase III randomized, controlled trials, and comment on its potential role in the treatment of other severe infections with drug-resistant Gram-positive pathogens.
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Affiliation(s)
- Andrew Morgan
- Veterans Affairs Medical Center, Boise, Idaho, USA and, Idaho State University School of Pharmacy, Pocatello, Idaho, USA
| | - Christine Cofer
- Veterans Affairs Medical Center, Boise, Idaho, USA and, University of Washington School of Medicine, Seattle, WA, USA
| | - Dennis L Stevens
- Infectious Disease Section, Veterans Affairs Medical Center, 500 West Fort Street, Boise, ID 83702, USA; and, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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