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Impact of Vancomycin MIC on Treatment Outcomes in Invasive Staphylococcus aureus Infections. Antimicrob Agents Chemother 2017; 61:AAC.01845-16. [PMID: 27956430 DOI: 10.1128/aac.01845-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/08/2016] [Indexed: 01/09/2023] Open
Abstract
There are conflicting data on the association of vancomycin MIC (VAN-MIC) with treatment outcomes in Staphylococcus aureus infections. We investigated the relationship between high VAN-MIC and 30-day mortality and identified the risk factors for mortality in a large cohort of patients with invasive S. aureus (ISA) infections, defined as the isolation of S. aureus from a normally sterile site. Over a 2-year period, 1,027 adult patients with ISA infections were enrolled in 10 hospitals, including 673 (66%) patients with methicillin-resistant S. aureus (MRSA) infections. There were 200 (19.5%) isolates with high VAN-MIC (≥1.5 mg/liter) by Etest and 87 (8.5%) by broth microdilution (BMD). The all-cause 30-day mortality rate was 27.4%. High VAN-MIC by either method was not associated with all-cause 30-day mortality, and this finding was consistent across MIC methodologies and methicillin susceptibilities. We conclude that high VAN-MIC is not associated with increased risk of all-cause 30-day mortality in ISA infections. Our data support the view that VAN-MIC alone is not sufficient evidence to change current clinical practice.
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52
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Thuny F, Habib G, Raoult D, Fournier PE. Endocarditis. Infect Dis (Lond) 2017. [DOI: 10.1016/b978-0-7020-6285-8.00051-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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53
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Giulieri SG, Holmes NE, Stinear TP, Howden BP. Use of bacterial whole-genome sequencing to understand and improve the management of invasive Staphylococcus aureus infections. Expert Rev Anti Infect Ther 2016; 14:1023-1036. [PMID: 27626511 DOI: 10.1080/14787210.2016.1233815] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Management of invasive Staphylococcus aureus infections is complex. Dramatic improvements in bacterial whole genome sequencing (WGS) offer new opportunities for personalising the treatment of S. aureus infections. Areas covered: We address recent achievements in S. aureus genomics, describe genetic determinants of antibiotic resistance and summarise studies that have defined molecular characteristics associated with risk and outcome of S. aureus invasive infections. Potential clinical use of WGS for resistance prediction, infection outcome stratification and management of persistent /relapsing infections is critically discussed. Expert commentary: WGS is not only providing invaluable information to track the emergence and spread of important S. aureus clones, but also allows rapid determination of resistance genotypes in the clinical environment. An evolving opportunity is to infer clinically important outcomes and optimal therapeutic approaches from widely available S. aureus genome data, with the goal of individualizing management of invasive S. aureus infections.
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Affiliation(s)
- Stefano G Giulieri
- a Microbiological Diagnostic Unit Public Health Laboratory , Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne , Australia.,b Infectious Diseases Service , Department of Medicine, Lausanne University Hospital , Lausanne , Switzerland
| | - Natasha E Holmes
- c Infectious Diseases Department , Austin Health , Heidelberg , Australia
| | - Timothy P Stinear
- d Doherty Applied Microbial Genomics , Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne , Australia.,e Department of Microbiology and Immunology , The University of Melbourne at the Peter Doherty Institute for Infection and Immunity , Melbourne , Australia
| | - Benjamin P Howden
- a Microbiological Diagnostic Unit Public Health Laboratory , Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne , Melbourne , Australia.,c Infectious Diseases Department , Austin Health , Heidelberg , Australia.,e Department of Microbiology and Immunology , The University of Melbourne at the Peter Doherty Institute for Infection and Immunity , Melbourne , Australia
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A Dysregulated Balance of Proinflammatory and Anti-Inflammatory Host Cytokine Response Early During Therapy Predicts Persistence and Mortality in Staphylococcus aureus Bacteremia. Crit Care Med 2016; 44:671-9. [PMID: 26540400 DOI: 10.1097/ccm.0000000000001465] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The contribution of individual immune response to Staphylococcus aureus bacteremia on outcome has not been well studied. The objective was to relate the host cytokine response to outcome of Staphylococcus aureus bacteremia. DESIGN Prospective observational study. SETTING Three U.S. university-affiliated medical centers. PATIENTS Adult patients infected with Staphylococcus aureus bacteremia hospitalized between July 2012 and August 2014. INTERVENTIONS Blood specimens were obtained at Staphylococcus aureus bacteremia onset and 72 hours after therapy initiation. Levels of tissue necrosis factor, interleukin-6, interleukin-8, interleukin-17A, and interleukin-10 were measured by enzyme-linked immunosorbent assay at each time point and compared between those with persistent bacteremia (≥ 4 d) and resolving bacteremia. Primary outcome was persistent bacteremia after 4 days of effective therapy. Secondary outcomes were 30-day mortality and 30-day recurrence. MEASUREMENTS AND MAIN RESULTS A total of 196 patients were included (mean age, 59 yr); of them, 33% had methicillin-resistant Staphylococcus aureus bacteremia. Forty-seven percent of the methicillin-resistant Staphylococcus aureus strains were staphylococcal cassette chromosome mec IV. Persistent bacteremia occurred in 24% of patients (47/196); they were more likely to die than resolving bacteremia group (28% vs 5%; p < 0.001). Compared with resolving bacteremia group, persistent bacteremia patients had higher initial median levels of tissue necrosis factor (44.73 vs 21.68 pg/mL; p < 0.001), interleukin-8 (124.76 vs 47.48 pg/mL; p = 0.028), and interleukin-10 (104.31 vs 29.72 pg/mL; p < 0.001). Despite 72 hours of treatment, levels remained higher for the persistent bacteremia group than for the resolving bacteremia group (tissue necrosis factor: 26.95 vs 18.38 pg/mL, p = 0.02; interleukin-8: 70.75 vs 27.86 pg/mL, p = 0.002; interleukin-6: 67.50 vs 21.81 pg/mL, p = 0.005; and interleukin-10: 30.98 vs 12.60 pg/mL, p < 0.001). Interleukin-17A levels were similar between groups at both time points. After controlling for confounding variables by multivariate analysis, interleukin-10/tissue necrosis factor ratio at 72 hours most significantly predicted persistence (odds ratio, 2.98; 95% CI, 1.39-6.39; p = 0.005) and mortality (odds ratio, 9.87; 95% CI, 2.64-36.91; p < 0.001) at values more than 1.00 and more than 2.56, respectively. CONCLUSIONS Sustained elevation of interleukin-10/tissue necrosis factor ratio at 72 hours suggests a dysregulated immune response and may be used to guide management to improve outcomes.
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55
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Berglund B, Claesson C, Nilsson LE, Hanberger H. High Prevalence of Heterogeneously Glycopeptide-Intermediate Coagulase-Negative Staphylococci in Sternal Wounds. Antimicrob Agents Chemother 2016; 60:5097-8. [PMID: 27216070 PMCID: PMC4958198 DOI: 10.1128/aac.00217-16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Björn Berglund
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Carina Claesson
- Department of Clinical Microbiology and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Lennart E Nilsson
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Håkan Hanberger
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
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Efficacy of Lantibiotic Treatment of Staphylococcus aureus-Induced Skin Infections, Monitored by In Vivo Bioluminescent Imaging. Antimicrob Agents Chemother 2016; 60:3948-55. [PMID: 27067340 DOI: 10.1128/aac.02938-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/08/2016] [Indexed: 02/02/2023] Open
Abstract
Staphylococcus aureus is a bacterial pathogen responsible for the majority of skin and soft tissue infections. Antibiotics are losing their efficacy as treatment for skin and soft tissue infections as a result of increased resistance in a variety of pathogens, including S. aureus It is thus imperative to explore alternative antimicrobial treatments to ensure future treatment options for skin and soft tissue infections. A select few lantibiotics, a group of natural defense peptides produced by bacteria, inhibit the growth of numerous clinical S. aureus isolates, including methicillin-resistant strains. In this study, the antimicrobial activities of nisin, clausin, and amyloliquecidin, separately administered, were compared to that of a mupirocin-based ointment, which is commonly used as treatment for S. aureus-induced skin infections. Full-thickness excisional wounds, generated on the dorsal surfaces of mice, were infected with a bioluminescent strain of S. aureus (strain Xen 36). The infections were monitored in real time using in vivo bioluminescent imaging. Lantibiotic treatments significantly reduced the bioluminescence of S. aureus Xen 36 to a level similar to that recorded with mupirocin treatment. Wound closure, however, was more pronounced during lantibiotic treatment. Lantibiotics thus have the potential to be used as an alternative treatment option for S. aureus-induced skin infections.
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57
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Adamantia L, Antoni T. Pharmacodynamics, pharmacokinetics and clinical efficacy of telavancin in the treatment of pneumonia. Expert Opin Drug Metab Toxicol 2016; 12:803-12. [DOI: 10.1080/17425255.2016.1187599] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
| | - Torres Antoni
- Department of Pneumology, Hospital Clinic of Barcelona, Barcelona, Spain
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58
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Chen H, Xiong Z, Liu K, Li S, Wang R, Wang X, Zhang Y, Wang H. Transcriptional profiling of the two-component regulatory system VraSR in Staphylococcus aureus with low-level vancomycin resistance. Int J Antimicrob Agents 2016; 47:362-7. [DOI: 10.1016/j.ijantimicag.2016.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 10/22/2022]
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59
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Methicillin-Resistant Staphylococcus aureus Grown on Vancomycin-Supplemented Screening Agar Displays Enhanced Biofilm Formation. Antimicrob Agents Chemother 2015; 59:7906-10. [PMID: 26459889 DOI: 10.1128/aac.00568-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/30/2015] [Indexed: 11/20/2022] Open
Abstract
Brain heart infusion agar containing 3 mg/liter vancomycin (BHI-V3) was used to screen for heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA). There was markedly greater biofilm formation by isolates that grew on BHI-V3 than by strains that did not grow on BHI-V3. Increased biofilm formation by hVISA may be mediated by FnbA- and polysaccharide intercellular adhesin-dependent pathways, and upregulation of atlA and sarA may also contribute to enhanced biofilm formation by hVISA upon prolonged exposure to vancomycin.
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60
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Habib G, Lancellotti P, Antunes MJ, Bongiorni MG, Casalta JP, Del Zotti F, Dulgheru R, El Khoury G, Erba PA, Iung B, Miro JM, Mulder BJ, Plonska-Gosciniak E, Price S, Roos-Hesselink J, Snygg-Martin U, Thuny F, Tornos Mas P, Vilacosta I, Zamorano JL. 2015 ESC Guidelines for the management of infective endocarditis: The Task Force for the Management of Infective Endocarditis of the European Society of Cardiology (ESC). Endorsed by: European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Nuclear Medicine (EANM). Eur Heart J 2015; 36:3075-3128. [PMID: 26320109 DOI: 10.1093/eurheartj/ehv319] [Citation(s) in RCA: 3132] [Impact Index Per Article: 348.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
MESH Headings
- Acute Kidney Injury/diagnosis
- Acute Kidney Injury/therapy
- Ambulatory Care
- Aneurysm, Infected/diagnosis
- Aneurysm, Infected/therapy
- Anti-Bacterial Agents/therapeutic use
- Antibiotic Prophylaxis
- Arrhythmias, Cardiac/diagnosis
- Arrhythmias, Cardiac/therapy
- Clinical Laboratory Techniques
- Critical Care
- Cross Infection/etiology
- Dentistry, Operative
- Diagnostic Imaging/methods
- Embolism/diagnosis
- Embolism/therapy
- Endocarditis/diagnosis
- Endocarditis/therapy
- Endocarditis, Non-Infective/diagnosis
- Endocarditis, Non-Infective/therapy
- Female
- Fibrinolytic Agents/therapeutic use
- Heart Defects, Congenital
- Heart Failure/diagnosis
- Heart Failure/therapy
- Heart Valve Diseases/diagnosis
- Heart Valve Diseases/therapy
- Humans
- Long-Term Care
- Microbiological Techniques
- Musculoskeletal Diseases/diagnosis
- Musculoskeletal Diseases/microbiology
- Musculoskeletal Diseases/therapy
- Myocarditis/diagnosis
- Myocarditis/therapy
- Neoplasms/complications
- Nervous System Diseases/diagnosis
- Nervous System Diseases/microbiology
- Nervous System Diseases/therapy
- Patient Care Team
- Pericarditis/diagnosis
- Pericarditis/therapy
- Postoperative Complications/etiology
- Postoperative Complications/prevention & control
- Pregnancy
- Pregnancy Complications, Cardiovascular/diagnosis
- Pregnancy Complications, Cardiovascular/therapy
- Prognosis
- Prosthesis-Related Infections/diagnosis
- Prosthesis-Related Infections/therapy
- Recurrence
- Risk Assessment
- Risk Factors
- Splenic Diseases/diagnosis
- Splenic Diseases/therapy
- Thoracic Surgical Procedures
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61
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Antibiofilm and membrane-damaging potential of cuprous oxide nanoparticles against Staphylococcus aureus with reduced susceptibility to vancomycin. Antimicrob Agents Chemother 2015; 59:6882-90. [PMID: 26303796 DOI: 10.1128/aac.01440-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/14/2015] [Indexed: 11/20/2022] Open
Abstract
The antimicrobial effects of copper ions and salts are well known, but the effects of cuprous oxide nanoparticles (Cu2O-NPs) on staphylococcal biofilms have not yet been clearly revealed. The present study evaluated Cu2O-NPs for their antibacterial and antibiofilm activities against heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate S. aureus (VISA). Nanoscaled Cu2O, generated by solution phase technology, contained Cu2O octahedral nanoparticles. Field emission electron microscopy demonstrated particles with sizes ranging from 100 to 150 nm. Cu2O-NPs inhibited the growth of S. aureus and showed antibiofilm activity. The MICs and minimum biofilm inhibitory concentrations ranged from 625 μg/ml to 5,000 μg/ml and from 2,500 μg/ml to 10,000 μg/ml, respectively. Exposure of S. aureus to Cu2O-NPs caused leakage of the cellular constituents and increased uptake of ethidium bromide and propidium iodide. Exposure also caused a significant reduction in the overall vancomycin-BODIPY (dipyrromethene boron difluoride [4,4-difluoro-4-bora-3a,4a-diaza-s-indacene] fluorescent dye) binding and a decrease in the viable cell count in the presence of 7.5% sodium chloride. Cu2O-NP toxicity assessment by hemolysis assay showed no cytotoxicity at 625 to 10,000 μg/ml concentrations. The results suggest that Cu2O-NPs exert their action by disruption of the bacterial cell membrane and can be used as effective antistaphylococcal and antibiofilm agents in diverse medical devices.
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62
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Henson KER, Levine MT, Wong EAH, Levine DP. Glycopeptide antibiotics: evolving resistance, pharmacology and adverse event profile. Expert Rev Anti Infect Ther 2015; 13:1265-78. [PMID: 26165756 DOI: 10.1586/14787210.2015.1068118] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The first glycopeptide antibiotic was vancomycin, isolated from the soil in the 1950s; since then, the class has expanded to include teicoplanin and the new semisynthetic glycopeptides dalbavancin, oritavancin and telavancin. They are bactericidal, active against most Gram-positive organisms, and in a concentration-dependent manner, inhibit cell wall synthesis. Resistance to vancomycin has emerged, especially among enterococci and Staphylococcus aureus through a variety of mechanisms. This emerging resistance to vancomycin makes proper dosing and monitoring of the area under the curve/MIC critically important. The chief adverse effect of vancomycin is nephrotoxicity, which is also intricately related to its dose. The efficacy of the semisynthetic glycopeptides has been demonstrated in skin and soft-tissue infections, but remains to be seen in serious methicillin-resistant Staphylococcus aureus infections.
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Affiliation(s)
- Karl Evans R Henson
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Miriam T Levine
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Eunice Ann H Wong
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA
| | - Donald P Levine
- a 1 Department of Medicine, Division of Infectious Diseases, Detroit Medical Center and Wayne State University School of Medicine, 4201 St Antoine St, Detroit, MI 48201, USA.,b 2 Department of Medicine, Division of General Internal Medicine, Detroit Receiving Hospital and University Health Center, Detroit, MI, USA
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63
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Singh A, Prasad KN, Misra R, Rahman M, Singh SK, Rai RP, Tripathi A, Srivastava JK. Increasing Trend of Heterogeneous Vancomycin Intermediate Staphylococcus aureus in a Tertiary Care Center of Northern India. Microb Drug Resist 2015; 21:545-50. [PMID: 26430942 DOI: 10.1089/mdr.2015.0004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Heterogeneous vancomycin intermediate Staphylococcus aureus (hVISA) strains are increasingly reported, and their association with vancomycin treatment failure is a well-known problem worldwide. A total of 500 clinical isolates of methicillin-resistant S. aureus were screened for hVISA by four different methods from May 2011 to May 2014. The number of strains screened for hVISA from May to April in 2011-2012, 2012-2013, and 2013-2014 were 198, 123, and 179, respectively. hVISA strains were studied by transmission electron microscopy (TEM) for cell wall thickness and also for their ability to form biofilm on a polystyrene microtiter plate. hVISA strains detected by four different methods-brain heart infusion agar with vancomycin with 4 mg/L/gradient plate/macro E-test/and glycopeptide resistance detection (GRD) E test-were as follows: 11.6%/10%/9%, and 9.5% in 2011-2012, 12.1%/9.7%/8.9%, and 10.5% in 2012-2013, and 13.9%/11.7%/11.1%, and 12.8% in 2013-2014, respectively. Population analysis profile-area under curve analysis confirmed hVISA in 4.5% (9/198), 6.5% (8/123), and 6.7% (12/179) in respective years; 24% (7/29) of hVISA isolates were nonsusceptible to daptomycin. TEM showed a significant increase in cell wall thickness of hVISA isolates (p<0.001) with a distinct reduction in their biofilm formation ability.
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Affiliation(s)
- Avinash Singh
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India .,2 Amity Institute of Biotechnology, Amity University Uttar Pradesh , Lucknow, Uttar Pradesh, India
| | - Kashi Nath Prasad
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
| | - Richa Misra
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
| | - Mohibur Rahman
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
| | - Satyendra Kumar Singh
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
| | - Ravi Prakash Rai
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
| | - Aparna Tripathi
- 1 Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences , Lucknow, Uttar Pradesh, India
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64
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Gomes DM, Ward KE, LaPlante KL. Clinical implications of vancomycin heteroresistant and intermediately susceptible Staphylococcus aureus. Pharmacotherapy 2015; 35:424-32. [PMID: 25884530 DOI: 10.1002/phar.1577] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Staphylococcus aureus (S. aureus) has proven to be a major pathogen with the emergence of methicillin-resistant S. aureus (MRSA) infections and recently with heteroresistant vancomycin-intermediate S. aureus (hVISA) and vancomycin-intermediate S. aureus (VISA) infections. Although vancomycin is traditionally a first-line and relatively effective antibiotic, its continued use is under question because reports of heteroresistance in S. aureus isolates are increasing. Both hVISA and VISA infections are associated with complicated clinical courses and treatment failures. The prevalence, mechanism of resistance, clinical significance, and laboratory detection of hVISA and VISA infections are not conclusive, making it difficult to apply research findings to clinical situations. We provide an evidence-based review of S. aureus isolates expressing heterogenic and reduced susceptibility to vancomycin.
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Affiliation(s)
- Diane M Gomes
- Department of Pharmacy Practice, University of Rhode Island, Kingston, Rhode Island; Veterans Affairs Medical Center, Providence, Rhode Island
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65
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Convergent adaptation in the dominant global hospital clone ST239 of methicillin-resistant Staphylococcus aureus. mBio 2015; 6:e00080. [PMID: 25736880 PMCID: PMC4358018 DOI: 10.1128/mbio.00080-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Infections caused by highly successful clones of hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) are a major public health burden. The globally dominant sequence type 239 (ST239) HA-MRSA clone has persisted in the health care setting for decades, but the basis of its success has not been identified. Taking a collection of 123 ST239 isolates spanning 32 years, we have used population-based functional genomics to investigate the evolution of this highly persistent and successful clone. Phylogenetic reconstruction and population modeling uncovered a previously unrecognized distinct clade of ST239 that was introduced into Australia from Asia and has perpetuated the epidemic in this region. Functional analysis demonstrated attenuated virulence and enhanced resistance to last-line antimicrobials, the result of two different phenomena, adaptive evolution within the original Australian ST239 clade and the introduction of a new clade displaying shifts in both phenotypes. The genetic diversity between the clades allowed us to employ genome-wide association testing and identify mutations in other essential regulatory systems, including walKR, that significantly associate with and may explain these key phenotypes. The phenotypic convergence of two independently evolving ST239 clades highlights the very strong selective pressures acting on HA-MRSA, showing that hospital environments have favored the accumulation of mutations in essential MRSA genes that increase resistance to antimicrobials, attenuate virulence, and promote persistence in the health care environment. Combinations of comparative genomics and careful phenotypic measurements of longitudinal collections of clinical isolates are giving us the knowledge to intelligently address the impact of current and future antibiotic usage policies and practices on hospital pathogens globally. Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for innumerable drug-resistant health care-associated infections globally. This study, the first to investigate the evolutionary response of hospital-associated MRSA (HA-MRSA) over many decades, demonstrates how MRSA can persist in a region through the reintroduction of a previously unrecognized distinct clade. This study also demonstrates the crucial adaptive responses of HA-MRSA to the highly selective environment of the health care system, the evolution of MRSA isolates to even higher levels of antibiotic resistance at the cost of attenuated virulence. However, in vivo persistence is maintained, resulting in a clone of HA-MRSA able to resist almost all antimicrobial agents and still cause invasive disease in the heavily compromised hosts found in modern health care settings.
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66
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Mirzaee M, Najar-Peerayeh S, Behmanesh M, Moghadam MF. Relationship between adhesin genes and biofilm formation in vancomycin-intermediate Staphylococcus aureus clinical isolates. Curr Microbiol 2015; 70:665-70. [PMID: 25572495 DOI: 10.1007/s00284-014-0771-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 12/01/2014] [Indexed: 12/22/2022]
Abstract
The adherence ability and biofilm production are the characteristic of enhanced virulence among isolates of vancomycin-intermediate Staphylococcus aureus (VISA) strains. Although biofilm-forming properties have been well demonstrated in S. aureus, they still remain unclear among the recently emerged types of VISA strains. The aim of this study was to investigate correlations between the distribution of genes encoding staphylococcal microbial surface components which recognise adhesive matrix molecules (MSCRAMMs), the surface protein A (Spa) types, MLST types and the ability of VISA strains to biofilm formation. Microtiter plate assay (Mtp) results showed that all eleven biofilm producer isolates were adherent at various levels. PCR experiments showed that nine MSCRAMM genes, clfA, clfB, fnbA and fib were detected in all of the strains, indicating a high prevalence. The prevalences of other MSCRAMMs and icaABCD genes were found to be variable and not equally distributed among the VISA strains. There was no direct correlation between the distribution of adhesion-related genes and biofilm formation, which indicates that the presence or absence of these genes cannot be employed as an indicator of the ability to biofilm formation. Isolates which belong to the same Spa and ST types showed similar adherence capacities in the Mtp assay, but significant differences were observed between different Spa types. The findings of this study, using quantitative methods, have shown that genotypically different strains of VISA have different capabilities to produce biofilms. This may be caused by a difference in the spa types of VISA isolates or due to their differences in the expression of MSCRAMM and icaABCD genes.
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Affiliation(s)
- Mohsen Mirzaee
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran,
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67
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Abdelhady W, Chen L, Bayer AS, Seidl K, Yeaman MR, Kreiswirth BN, Xiong YQ. Early agr activation correlates with vancomycin treatment failure in multi-clonotype MRSA endovascular infections. J Antimicrob Chemother 2015; 70:1443-52. [PMID: 25564565 DOI: 10.1093/jac/dku547] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 12/03/2014] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVES Persistent MRSA infections are especially relevant to endovascular infections and correlate with suboptimal outcomes. However, the virulence signatures of Staphylococcus aureus that drive such persistence outcomes are not well defined. In the current study, we investigated correlations between accessory gene regulator (agr) activation and the outcome of vancomycin treatment in an experimental model of infective endocarditis (IE) due to MRSA strains with different agr and clonal complex (CC) types. METHODS Twelve isolates with the four most common MRSA CC and agr types (CC5-agr II, CC8-agr I, CC30-agr III and CC45-agr I) were evaluated for heterogeneous vancomycin-intermediate S. aureus (hVISA), agr function, agrA and RNAIII transcription, agr locus sequences, virulence and response to vancomycin in the IE model. RESULTS Early agr RNAIII activation (beginning at 2 h of growth) in parallel with strong δ-haemolysin production correlated with persistent outcomes in the IE model following vancomycin therapy. Importantly, such treatment failures occurred across the range of CC/agr types studied. In addition, these MRSA strains: (i) were vancomycin susceptible in vitro; (ii) were not hVISA or vancomycin tolerant; and (iii) did not evolve hVISA phenotypes or perturbed δ-haemolysin activity in vivo following vancomycin therapy. Moreover, agr locus sequence analyses revealed no common point mutations that correlated with either temporal RNAIII transcription or vancomycin treatment outcomes, encompassing different CC and agr types. CONCLUSIONS These data suggest that temporal agr RNAIII activation and agr functional profiles may be useful biomarkers to predict the in vivo persistence of endovascular MRSA infections despite vancomycin therapy.
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Affiliation(s)
- Wessam Abdelhady
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Liang Chen
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Arnold S Bayer
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Kati Seidl
- University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michael R Yeaman
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Barry N Kreiswirth
- Public Health Research Institute, NJMS-Rutgers University, Newark, NJ, USA
| | - Yan Q Xiong
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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68
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Chang SC, Liu TP, Chen CJ, Lin LC, Lu JJ. Detection of heterogeneous vancomycin-intermediate Staphylococcus aureus isolates using a combination of δ-hemolysis assay and Etest. Diagn Microbiol Infect Dis 2014; 81:246-50. [PMID: 25600843 DOI: 10.1016/j.diagmicrobio.2014.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/16/2014] [Accepted: 12/21/2014] [Indexed: 12/23/2022]
Abstract
This study evaluated the δ-hemolysis assay for detection of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) isolates. The assay was performed using Columbia or trypticase soy blood agar plates without vancomycin at 37°C with 5% CO2, and the test isolate was streaked perpendicularly 1mm away from S. aureus RN4220. One hundred thirty-eight methicillin-resistant S. aureus (MRSA) bloodstream isolates with vancomycin MICs of 0.75-2 μg/mL were screened for hVISA by the δ-hemolysis assay and Etest glycopeptide resistance detection (GRD) method. The δ-hemolysis assay could be read at 24h and was more sensitive and specific than the Etest GRD at 24h and 48 h for detection of hVISA. Because most hVISA isolates have a vancomycin MIC of 2 μg/mL, we recommend screening MRSA isolates first using Etest for those with an MIC of 2 μg/mL and then performing the δ-hemolysis assay on these isolates for hVISA.
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Affiliation(s)
- Shih-Cheng Chang
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tsui-Ping Liu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Chih-Jung Chen
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Children's Hospital and Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lee-Chung Lin
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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Berscheid A, François P, Strittmatter A, Gottschalk G, Schrenzel J, Sass P, Bierbaum G. Generation of a vancomycin-intermediate Staphylococcus aureus (VISA) strain by two amino acid exchanges in VraS. J Antimicrob Chemother 2014; 69:3190-8. [PMID: 25103491 DOI: 10.1093/jac/dku297] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES Staphylococcus aureus is a notorious bacterial pathogen and antibiotic-resistant isolates complicate current treatment strategies. We characterized S. aureus VC40, a laboratory mutant that shows full resistance to glycopeptides (vancomycin and teicoplanin MICs ≥32 mg/L) and daptomycin (MIC = 4 mg/L), to gain deeper insights into the underlying resistance mechanisms. METHODS Genomics and transcriptomics were performed to characterize changes that might contribute to development of resistance. The mutations in vraS were reconstituted into a closely related parental background. In addition, antimicrobial susceptibility testing, growth analyses, transmission electron microscopy, lysostaphin-induced lysis and autolysis assays were performed to characterize the phenotype of resistant strains. RESULTS Genome sequencing of strain VC40 revealed 79 mutations in 75 gene loci including genes encoding the histidine kinases VraS and WalK that control cell envelope-related processes. Transcriptomics indicated the increased expression of their respective regulons. Although not reaching the measured MIC for VC40, reconstitution of the L114S and D242G exchanges in VraS(VC40) into the susceptible parental background (S. aureus NCTC 8325) resulted in increased resistance to glycopeptides and daptomycin. The expression of VraS(VC40) led to increased transcription of the cell wall stress stimulon, a thickened cell wall, a decreased growth rate, reduced autolytic activity and increased resistance to lysostaphin-induced lysis in the generated mutant. CONCLUSIONS We show that a double mutation of a single gene locus, namely vraS, is sufficient to convert the vancomycin-susceptible strain S. aureus NCTC 8325 into a vancomycin-intermediate S. aureus.
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Affiliation(s)
- Anne Berscheid
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University of Bonn, Bonn, Germany
| | - Patrice François
- Genomic Research Laboratory, Infectious Diseases Service, Geneva University Hospitals and the University of Geneva, Geneva, Switzerland
| | - Axel Strittmatter
- Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Gerhard Gottschalk
- Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Jacques Schrenzel
- Genomic Research Laboratory, Infectious Diseases Service, Geneva University Hospitals and the University of Geneva, Geneva, Switzerland
| | - Peter Sass
- Institute for Pharmaceutical Biology, University of Düsseldorf, Düsseldorf, Germany
| | - Gabriele Bierbaum
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University of Bonn, Bonn, Germany
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Gardete S, Tomasz A. Mechanisms of vancomycin resistance in Staphylococcus aureus. J Clin Invest 2014; 124:2836-40. [PMID: 24983424 DOI: 10.1172/jci68834] [Citation(s) in RCA: 315] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Vancomycin is a glycopeptide antibiotic used for the treatment of Gram-positive bacterial infections. Traditionally, it has been used as a drug of last resort; however, clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased susceptibility to vancomycin (vancomycin intermediate-resistant S. aureus [VISA]) and more recently with high-level vancomycin resistance (vancomycin-resistant S. aureus [VRSA]) have been described in the clinical literature. The rare VRSA strains carry transposon Tn1546, acquired from vancomycin-resistant Enterococcus faecalis, which is known to alter cell wall structure and metabolism, but the resistance mechanisms in VISA isolates are less well defined. Herein, we review selected mechanistic aspects of resistance in VISA and summarize biochemical studies on cell wall synthesis in a VRSA strain. Finally, we recapitulate a model that integrates common mechanistic features of VRSA and VISA strains and is consistent with the mode of action of vancomycin.
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Evaluation of vancomycin population susceptibility analysis profile as a predictor of outcomes for patients with infective endocarditis due to methicillin-resistant Staphylococcus aureus. Antimicrob Agents Chemother 2014; 58:4636-41. [PMID: 24890596 DOI: 10.1128/aac.02820-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infective endocarditis due to methicillin-resistant Staphylococcus aureus (MRSA IE) is associated with high morbidity and mortality. Vancomycin continues to be the primary treatment for this disease. The emergence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA), defined as a modified population analysis profile (PAP) of ≥ 0.9, may affect patient outcomes. The objective of this study was to evaluate the relationship of vancomycin subpopulation susceptibility and the clinical outcomes of MRSA IE. We conducted a retrospective cohort study of patients treated with vancomycin for MRSA IE from 2002 to 2013 at the Detroit Medical Center. A modified PAP was used to measure the vancomycin PAP MIC and the PAP-to-area under the curve (AUC) ratio. Treatment failure was defined as bacteremia for ≥ 7 days or death attributed to MRSA. Classification and regression tree (CART) analysis was used to select a failure breakpoint between the PAP-AUC ratios and the PAP MIC. A total of 202 patients were included in the study. Twenty-seven percent of the patients had left-sided IE, 19% of the strains were hVISA, and 70% of the strains were staphylococcal cassette chromosome mec element (SCCmec) type IV. Overall treatment failure was observed in 64%; 59% had persistent bacteremia, and the 30-day attributable mortality rate was 21%. The CART breakpoint between failure and success in terms of the PAP-AUC ratio was 0.9035. On logistic regression analysis, intensive care unit (ICU) admission (adjusted odds ratio [aOR], 2.8; 95% confidence interval [CI], 1.5 to 5.2) and a PAP MIC of ≥ 4 mg/liter (aOR, 3.2; 95% CI, 1.3 to 8.4) were associated with failure (P = 0.001 and 0.015, respectively). A PAP MIC of ≥ 4 mg/liter and ICU admission were significant for treatment failure for patients with MRSA IE. The PAP-AUC ratio of ≥ 0.9035 predicted failure consistent with the hVISA definition. The role of population MIC analysis in predicting outcome with MRSA infections warrants further investigation.
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72
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Sharma P, Tomar SK, Goswami P, Sangwan V, Singh R. Antibiotic resistance among commercially available probiotics. Food Res Int 2014. [DOI: 10.1016/j.foodres.2014.01.025] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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73
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Bugs, hosts and ICU environment: countering pan-resistance in nosocomial microbiota and treating bacterial infections in the critical care setting. ACTA ACUST UNITED AC 2014; 61:e1-e19. [PMID: 24492197 DOI: 10.1016/j.redar.2013.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/04/2013] [Indexed: 02/07/2023]
Abstract
ICUs are areas where resistance problems are the largest, and these constitute a major problem for the intensivist's clinical practice. Main resistance phenotypes among nosocomial microbiota are (i) vancomycin-resistance/heteroresistance and tolerance in grampositives (MRSA, enterococci) and (ii) efflux pumps/enzymatic resistance mechanisms (ESBLs, AmpC, metallo-betalactamases) in gramnegatives. These phenotypes are found at different rates in pathogens causing respiratory (nosocomial pneumonia/ventilator-associated pneumonia), bloodstream (primary bacteremia/catheter-associated bacteremia), urinary, intraabdominal and surgical wound infections and endocarditis in the ICU. New antibiotics are available to overcome non-susceptibility in grampositives; however, accumulation of resistance traits in gramnegatives has led to multidrug resistance, a worrisome problem nowadays. This article reviews microorganism/infection risk factors for multidrug resistance, suggesting adequate empirical treatments. Drugs, patient and environmental factors all play a role in the decision to prescribe/recommend antibiotic regimens in the specific ICU patient, implying that intensivists should be familiar with available drugs, environmental epidemiology and patient factors.
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Deresinski S. Vancomycin: does it still have a role as an antistaphylococcal agent? Expert Rev Anti Infect Ther 2014; 5:393-401. [PMID: 17547504 DOI: 10.1586/14787210.5.3.393] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The recognition of the shortcomings of vancomycin as an antistaphylococcal agent, together with the burgeoning availability of alternative effective antistaphylococcal antibiotics, has led to a reassessment of the role of this glycopeptide antimicrobial in clinical therapeutics. Evidence indicates that vancomycin is inferior to semisynthetic penicillins in the treatment of infections due to methicillin-susceptible Staphylococcus aureus. Additional evidence suggests that vancomycin may be inferior to some comparator agents in the treatment of infections due to methicillin-resistant S. aureus (MRSA). While high-level resistance remains rare, data from some centers suggest an evolutionary change in S. aureus, evidenced by reduced susceptibility to vancomycin. This, together with the problem of heteroresistance to vancomycin, as well as poor tissue penetration after its systemic administration, presents potential obstacles to the successful therapy of S. aureus infections with this glycopeptide. While it has been suggested that these problems may be overcome by administration of vancomycin in much higher doses, the efficacy and safety of this approach remains to be determined and will require randomized clinical trials for its demonstration. A number of novel agents with activity against MRSA have been introduced to clinical practice in the last 2 years and others are still in the investigational stage. Despite the fact that these newer agents have been compared with vancomycin in trials only designed to demonstrate noninferiority, some potential evidence of superiority over vancomycin has emerged. While the relative roles of each of these newer agents and vancomycin can only be determined definitively by performance of adequately powered randomized clinical trials, current evidence suggests that vancomycin may be an inferior therapeutic agent.
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Affiliation(s)
- Stan Deresinski
- Division of Infectious Disease and Geographic Medicine, Stanford University, Stanford, CA, USA.
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75
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High vancomycin minimum inhibitory concentrations with heteroresistant vancomycin-intermediate Staphylococcus aureus in meticillin-resistant S. aureus bacteraemia patients. Int J Antimicrob Agents 2013; 42:390-4. [DOI: 10.1016/j.ijantimicag.2013.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 07/11/2013] [Accepted: 07/23/2013] [Indexed: 11/13/2022]
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76
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Frequency of susceptibility testing for patients with persistent methicillin-resistant Staphylococcus aureus bacteremia. J Clin Microbiol 2013; 52:357-61. [PMID: 24153125 DOI: 10.1128/jcm.02081-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Currently, no standards exist for determining the optimal frequency of repeat antimicrobial susceptibility testing (AST) when an organism is recurrently isolated from the same specimen source. Although testing every 2 to 5 days is thought sufficient, we present three cases of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia where current laboratory protocol for repeating AST every 5 days was inadequate to identify resistant organisms.
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77
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Alexander EL, Satlin MJ, Gamaletsou MN, Sipsas NV, Walsh TJ. Worldwide challenges of multidrug-resistant bacteria in patients with hematologic malignancies. Int J Hematol Oncol 2013. [DOI: 10.2217/ijh.13.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY The emergence of infections due to multidrug-resistant (MDR) bacteria poses a major public health threat to all patients, but patients with hematologic malignancies are especially at risk. A common thread across all classes of bacteria is that increased reliance on and usage of broad-spectrum antibacterial agents, combined with the intrinsic ability of bacteria to develop and transmit resistance-conferring mutations, has led to the widespread dissemination of MDR organisms. In this article, we summarize the most worrisome MDR bacteria, assess their clinical impact on patients with hematologic malignancies and outline measures that are required to mitigate this impact.
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Affiliation(s)
| | - Michael J Satlin
- Division of Infectious Diseases, Weill Cornell Medical Center, New York, NY, USA
- Transplantation–Oncology Infectious Diseases Program, Department of Medicine, Weill Cornell Medical Center, New York, NY, USA
| | - Maria N Gamaletsou
- University of Athens School of Medicine & Laikon Hospital, Athens, Greece
| | - Nikolaos V Sipsas
- University of Athens School of Medicine & Laikon Hospital, Athens, Greece
| | - Thomas J Walsh
- Department of Pediatrics, Weill Cornell Medical Center, New York, NY, USA
- Department of Microbiology & Immunology, Weill Cornell Medical Center, New York, NY, USA
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78
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Hu J, Ma XX, Tian Y, Pang L, Cui LZ, Shang H. Reduced vancomycin susceptibility found in methicillin-resistant and methicillin-sensitive Staphylococcus aureus clinical isolates in Northeast China. PLoS One 2013; 8:e73300. [PMID: 24069184 PMCID: PMC3772004 DOI: 10.1371/journal.pone.0073300] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/18/2013] [Indexed: 11/18/2022] Open
Abstract
Background Strains of Staphylococcus aureus with an intermediate level of resistance to vancomycin (vancomycin-intermediate S. aureus, or VISA) or which contain subpopulations of mixed susceptibility (heterogeneous VISA, or hVISA) have been reported worldwide. However, the prevalence of VISA and hVISA infections in Northeast China is unknown. From 2007 through 2010, we surveyed the vancomycin susceptibility of methicillin-resistant and methicillin-sensitive S. aureus (MRSA and MSSA, respectively) clinical isolates in Northeast China. Methods S. aureus clinical isolates (369 MRSA and 388 MSSA) were screened for hVISA and VISA on brain heart infusion agar containing 3 μg/mL vancomycin, and their identity confirmed using a modified population analysis profile-area under the curve method and broth microdilution. All hVISA and VISA isolates were characterized genotypically and phenotypically. Results Ten percent and 0.5 percent of the isolates were hVISA and VISA, respectively. The proportion of hVISA among MSSA isolates for the entire study period was 4.1%, but increased significantly year-by-year, from 1.2% in 2007 to 7.2% in 2010. The predominant sources of hVISA and VISA isolates were sputum (56.3%), pus (18.8%), and blood (8.8%). Molecular typing of hVISA and VISA strains revealed that, taken together, 80% contained the accessory gene regulator (agr) group II, and of these, 85.7% of the MR-hVISA and MR-VISA strains were staphylococcal cassette chromosome mec (SCCmec) type II. The adherence ability of all hVISA and VISA strains was reduced compared with that of vancomycin-susceptible strains, shown by biofilm assay. Conclusions The percentage of hVISA strains was high and increased each year. The proportion of hVISA among MSSA specifically also increased significantly each year. In isolates collected from diverse infection sites, hVISA and VISA strains were found predominantly in sputum, pus, and blood, in descending order. Testing for vancomycin susceptibility should include both MRSA and MSSA isolates collected from different clinical sites.
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Affiliation(s)
- Jian Hu
- Department of Medical Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, People's Republic of China
- Department of Clinical Laboratory, Yixing Hospital of Traditional Chinese Medicine, Yixing, Jiangsu, People's Republic of China
| | - Xiao Xue Ma
- Department of Medical Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, People's Republic of China
| | - Yuan Tian
- Department of Medical Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, People's Republic of China
| | - Long Pang
- Department of Medical Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, Shenyang, People's Republic of China
| | - Long Zhu Cui
- Research Center for Anti-infectious Drugs, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Hong Shang
- Department of Clinical Laboratory, First Affiliated Hospital of China Medical University, Shenyang, People's Republic of China
- * E-mail:
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Kumar PS, Cunnion KM. Acute MRSA sinusitis with intracranial extension and marginal vancomycin susceptibility. Case Rep Pediatr 2013; 2013:153239. [PMID: 24106631 PMCID: PMC3784153 DOI: 10.1155/2013/153239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/13/2013] [Indexed: 11/17/2022] Open
Abstract
Methicillin resistant Staphylococcus aureus (MRSA) is increasingly being described as a cause of acute sinusitis. We present a patient with acute MRSA sinusitis complicated by rapid intracranial extension, marginal vancomycin susceptibility (MIC = 2 mg/L), delayed drainage of intracranial abscess, and subsequent development of rifampin resistance. Given the relatively high risk of intracranial extension of severe acute bacterial sinusitis and high mortality associated with invasive MRSA infections, we suggest early surgical drainage of intracranial abscesses in these circumstances. We believe this is important given the limited intracranial penetration of currently available treatment options for MRSA, especially those with a vancomycin minimal inhibitory concentration (MIC) of ≥2 mg/L.
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Affiliation(s)
- Parvathi S. Kumar
- Department of Pediatrics, Division of Infectious Diseases, Children's Hospital of the King's Daughters and EVMS, Norfolk, VA 23507, USA
| | - Kenji M. Cunnion
- Department of Pediatrics, Division of Infectious Diseases, Children's Hospital of the King's Daughters and EVMS, Norfolk, VA 23507, USA
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Chen H, Liu Y, Zhao C, Xiao D, Zhang J, Zhang F, Chen M, Wang H. Comparative proteomics-based identification of genes associated with glycopeptide resistance in clinically derived heterogeneous vancomycin-intermediate Staphylococcus aureus strains. PLoS One 2013; 8:e66880. [PMID: 23840544 PMCID: PMC3696005 DOI: 10.1371/journal.pone.0066880] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/10/2013] [Indexed: 11/29/2022] Open
Abstract
Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) is associated with clinical treatment failure. However, the resistance mechanism of hVISA has not been fully clarified. In the present study, comparative proteomics analysis of two pairs of isogenic vancomycin-susceptible S. aureus (VSSA) and hVISA strains isolated from two patients identified five differentially expressed proteins, IsaA, MsrA2, Asp23, GpmA, and AhpC, present in both isolate pairs. All the proteins were up-regulated in the hVISA strains. These proteins were analyzed in six pairs of isogenic VSSA and hVISA strains, and unrelated VSSA (n = 30) and hVISA (n = 24) by real-time quantitative reverse transcriptase–PCR (qRT–PCR). Of the six pairs of isogenic strains, isaA, msrA2 and ahpC were up-regulated in all six hVISA strains; whereas asp23 and gpmA were up-regulated in five hVISA strains compared with the VSSA parental strains. In the unrelated strains, statistical analyses showed that only isaA was significantly up-regulated in the hVISA strains. Analysis of the five differentially expressed proteins in 15 pairs of persistent VSSA strains by qRT–PCR showed no differences in the expression of the five genes among the persistent strains, suggesting that these genes are not associated with persistence infection. Our results indicate that increased expression of isaA may be related to hVISA resistance.
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Affiliation(s)
- Hongbin Chen
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, People's Republic of China
| | - Yali Liu
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, People's Republic of China
| | - Chunjiang Zhao
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, People's Republic of China
| | - Di Xiao
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Jianzhong Zhang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, People's Republic of China
| | - Feifei Zhang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, People's Republic of China
| | - Minjun Chen
- Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, People's Republic of China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, People's Republic of China
- * E-mail:
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Clinical Outcomes in Patients with Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Bloodstream Infection. Antimicrob Agents Chemother 2013; 57:4252-4259. [PMID: 23796929 DOI: 10.1128/aac.00380-13] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 06/14/2013] [Indexed: 01/30/2023] Open
Abstract
The prevalence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) infections varies in the literature, a problem complicated by the lack of routine screening procedures; however, limited data suggest that hVISA has been associated with persistent bloodstream infections (BSI) and vancomycin failure, yet these studies have been confounded by design issues. We conducted this study to compare the characteristics of patients with BSI caused by hVISA with those with vancomycin-susceptible Staphylococcus aureus (VSSA) treated with vancomycin. This retrospective, multicenter matched (1:1) cohort study compared the clinical characteristics and outcomes of hVISA and VSSA. Patients with hVISA methicillin-resistant Staphylococcus aureus (MRSA) BSI from 2004 to 2012 were matched to VSSA-MRSA BSI patients. The primary outcome was failure of vancomycin treatment, defined as a composite of persistent bacteremia (≥7 days), persistent signs and symptoms, change of MRSA antibiotic, recurrent BSI, or MRSA-related mortality. We identified 122 matched cases. The overall vancomycin failure rate was 57% (82% hVISA versus 33% VSSA; P < 0.001). The individual components of failure in hVISA versus VSSA were persistent bacteremia, 59% versus 21% (P < 0.001); change in MRSA therapy, 54% versus 25% (P = 0.001); MRSA-related mortality, 21% versus 10% (P = 0.081); and recurrence of BSI, 26% versus 2% (P < 0.001). Using logistic regression analysis and adjusting for covariates, hVISA (adjusted odds ratio [aOR], 11.1; 95% confidence interval [CI], 4.3 to 28.7) and intensive care unit (ICU) admission (aOR, 4.5; 95% CI, 1.8 to 11.6) were still independently associated with vancomycin failure. Relative to VSSA BSI, patients with hVISA were more likely to experience failure of vancomycin treatment, including persistent bacteremia and recurrence. Our results indicate that hVISA was responsible for considerable morbidity.
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Analysis of the small RNA transcriptional response in multidrug-resistant Staphylococcus aureus after antimicrobial exposure. Antimicrob Agents Chemother 2013; 57:3864-74. [PMID: 23733475 DOI: 10.1128/aac.00263-13] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The critical role of noncoding small RNAs (sRNAs) in the bacterial response to changing conditions is increasingly recognized. However, a specific role for sRNAs during antibiotic exposure has not been investigated in Staphylococcus aureus. Here, we used Illumina RNA-Seq to examine the sRNA response of multiresistant sequence type 239 (ST239) S. aureus after exposure to four antibiotics (vancomycin, linezolid, ceftobiprole, and tigecycline) representing the major classes of antimicrobials used to treat methicillin-resistant S. aureus (MRSA) infections. We identified 409 potential sRNAs and then compared global sRNA and mRNA expression profiles at 2 and 6 h, without antibiotic exposure and after exposure to each antibiotic, for a vancomycin-susceptible strain (JKD6009) and a vancomycin-intermediate strain (JKD6008). Exploration of this data set by multivariate analysis using a novel implementation of nonnegative matrix factorization (NMF) revealed very different responses for mRNA and sRNA. Where mRNA responses clustered with strain or growth phase conditions, the sRNA responses were predominantly linked to antibiotic exposure, including sRNA responses that were specific for particular antibiotics. A remarkable feature of the antimicrobial response was the prominence of antisense sRNAs to genes encoding proteins involved in protein synthesis and ribosomal function. This study has defined a large sRNA repertoire in epidemic ST239 MRSA and shown for the first time that a subset of sRNAs are part of a coordinated transcriptional response to specific antimicrobial exposures in S. aureus. These data provide a framework for interrogating the role of staphylococcal sRNAs in antimicrobial resistance and exploring new avenues for sRNA-based antimicrobial therapies.
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84
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Decreased vancomycin susceptibility in Staphylococcus aureus caused by IS256 tempering of WalKR expression. Antimicrob Agents Chemother 2013; 57:3240-9. [PMID: 23629723 DOI: 10.1128/aac.00279-13] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Vancomycin-intermediate Staphylococcus aureus (VISA) strains often arise by mutations in the essential two-component regulator walKR; however their impact on walKR function has not been definitively established. Here, we investigated 10 MRSA strains recovered serially after exposure of vancomycin-susceptible S. aureus (VSSA) JKD6009 to simulated human vancomycin dosing regimens (500 mg to 4,000 mg every 12 h) using a 10-day hollow fiber infection model. After continued exposure to the vancomycin regimens, two isolates displayed reduced susceptibility to both vancomycin and daptomycin, developing independent IS256 insertions in the walKR 5' untranslated region (5' UTR). Quantitative reverse transcription-PCR (RT-PCR) revealed a 50% reduction in walKR gene expression in the IS256 mutants compared to the VSSA parent. Green fluorescent protein (GFP) reporter analysis, promoter mapping, and site-directed mutagenesis confirmed these findings and showed that the IS256 insertions had replaced two SigA-like walKR promoters with weaker, hybrid promoters. Removal of IS256 reverted the phenotype to VSSA, showing that reduced expression of WalKR did induce the VISA phenotype. Analysis of selected WalKR-regulated autolysins revealed upregulation of ssaA but no change in expression of sak and sceD in both IS256 mutants. Whole-genome sequencing of the two mutants revealed an additional IS256 insertion within agrC for one mutant, and we confirmed that this mutation abolished agr function. These data provide the first substantial analysis of walKR promoter function and show that prolonged vancomycin exposure can result in VISA through an IS256-mediated reduction in walKR expression; however, the mechanisms by which this occurs remain to be determined.
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85
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Evaluation of vancomycin susceptibility testing for methicillin-resistant Staphylococcus aureus: comparison of Etest and three automated testing methods. J Clin Microbiol 2013; 51:2077-81. [PMID: 23596249 DOI: 10.1128/jcm.00448-13] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We evaluated the ability of four commercial MIC testing systems (MicroScan, Vitek 2, Phoenix, and Etest) to detect vancomycin MIC values of ≤1 to ≥2 in 200 methicillin-resistant Staphylococcus aureus (MRSA) strains compared to the Clinical and Laboratory Standards Institute broth microdilution (BMD) reference methods. Compared to the BMD method, absolute agreement (0 ± dilution) was highest for the Phoenix system (66.2%) and the MicroScan turbidity method (61.8%), followed by the Vitek 2 system (54.3%). The Etest produced MIC values 1 to 2 dilutions higher than those produced by the BMD method (36.7% agreement). Of interest, the MicroScan system (prompt method) was more likely to overcall an MIC value of 1 mg/liter (74.1%), whereas the Phoenix (76%) and Vitek 2 (20%) systems had a tendency to undercall an MIC of 2 mg/liter. The ability to correctly identify vancomycin MIC values of 1 and 2 has clinical implications and requires further evaluation.
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86
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Howden BP, Peleg AY, Stinear TP. The evolution of vancomycin intermediate Staphylococcus aureus (VISA) and heterogenous-VISA. INFECTION GENETICS AND EVOLUTION 2013; 21:575-82. [PMID: 23567819 DOI: 10.1016/j.meegid.2013.03.047] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/20/2013] [Accepted: 03/29/2013] [Indexed: 12/01/2022]
Abstract
Resistance to new antimicrobials is generally recognized in Staphylococcus aureus soon after they are released for clinical use. In the case of vancomycin, which was first released in the 1950s, resistance was not reported until the mid 1990s, with the description of vancomycin-intermediate S. aureus (VISA), and heterogenous-VISA (hVISA). Unraveling the complex genetic and cell wall structural changes conferring low-level vancomycin resistance in S. aureus has proved challenging. However the recent advances in high throughput whole-genome sequencing has played a key role in determining the breadth of bacterial chromosomal changes linked with resistance. Diverse mutations in a small number of staphylococcal regulatory genes, in particular walKR, graRS, vraSR and rpoB, have been associated with hVISA and VISA. Only a small number of these mutations have been experimentally proven to confer the resistance phenotype and some of these only partially contribute to resistance. It also appears that the evolution of VISA from VSSA is a step-wise process. Transcriptomics studies, and analysis of host pathogen interactions, indicate that the evolution of vancomycin-susceptible S. aureus to VISA is associated not only with antibiotic resistance, but with other changes likely to promote persistent infection. These include predicted alterations in central metabolism, altered expression of virulence associated factors, attenuated virulence in vivo, and alterations in susceptibility to host innate immune responses, together with reduced susceptibility to other antibiotics. In fact, current data suggests that hVISA and VISA represent a bacterial evolutionary state favoring persistence in the face of not only antibiotics, but also the host environment. The additional knowledge of staphylococcal biology that has been uncovered during the study of hVISA and VISA is significant. The present review will detail the current understanding of the evolutionary process in the generation of hVISA and VISA, and explore the diverse additional changes that occur in these strains.
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Affiliation(s)
- Benjamin P Howden
- Austin Centre for Infection Research (ACIR), Infectious Diseases Department, Austin Health, Heidelberg, Victoria, Australia; Microbiology Department, Austin Health, Heidelberg, Victoria, Australia; Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia.
| | - Anton Y Peleg
- Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia; Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Boston, MA, United States; Department of Infectious Diseases, The Alfred Hospital, Melbourne, Australia
| | - Timothy P Stinear
- Department of Microbiology and Immunology, University of Melbourne, Victoria, Australia; Department of Microbiology, Monash University, Wellington Rd, Clayton, Victoria, Australia
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87
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Abstract
Acute rhinosinusitis is a common illness in children. Viral upper respiratory tract infection is the most common presentation of rhinosinusitis. Most children resolve the infection spontaneously and only a small proportion develops a secondary bacterial infection. The proper choice of antibiotic therapy depends on the likely infecting pathogens, bacterial antibiotic resistance, and pharmacologic profiles of antibiotics. Amoxicillin-clavulanate is currently recommended as the empiric treatment in those requiring antimicrobial therapy. Isolation of the causative agents should be considered in those who failed the initial treatment. In addition to antibiotics, adjuvant therapies and surgery may be used in the management of acute bacterial rhinosinusitis.
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88
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Chong YP, Park SJ, Kim HS, Kim ES, Kim MN, Park KH, Kim SH, Lee SO, Choi SH, Jeong JY, Woo JH, Kim YS. Persistent Staphylococcus aureus bacteremia: a prospective analysis of risk factors, outcomes, and microbiologic and genotypic characteristics of isolates. Medicine (Baltimore) 2013; 92:98-108. [PMID: 23429353 PMCID: PMC4553980 DOI: 10.1097/md.0b013e318289ff1e] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Persistent Staphylococcus aureus bacteremia (SAB) that fails to respond to appropriate antibiotic therapy is associated with poor outcomes. Comprehensive prospective studies on risk factors and outcomes of persistent bacteremia are limited. We investigated outcomes and risk factors encompassing clinical, pharmacokinetic, microbiologic, and genotypic characteristics associated with persistent bacteremia using a case-control study nested in a prospective cohort of patients with SAB at a tertiary-care hospital from August 2008 through September 2010. We compared the clinical characteristics, management, and outcomes of patients with persistent bacteremia (≥7 d) with controls with resolving bacteremia (<3 d). To detect associations between microbiologic and genotypic characteristics of methicillin-resistant S. aureus (MRSA) isolates and persistent bacteremia, we determined the heteroresistance phenotype, SCCmec type, agr genotype and functionality, multilocus sequence typing, and presence of 41 virulence genes. Our cohort consisted of 483 patients; 76 (15.7%) had persistent bacteremia, 212 (43.5%) had resolving bacteremia. In the multivariate analysis, independent risk factors associated with persistent bacteremia were community-onset bacteremia (odds ratio [OR], 2.91; 95% confidence interval [CI], 1.24-6.87), bone and joint infection (OR, 5.26; 95% CI, 1.45-19.03), central venous catheter-related infection (OR, 3.36; 95% CI, 1.47-7.65), metastatic infection (OR, 36.22; 95% CI, 12.71-103.23), and methicillin resistance (OR, 16.99; 95% CI, 5.53-52.15). For patients with eradicable foci, delay (>3 d) in the removal of the infection focus was significantly associated with persistent bacteremia (OR, 2.18; 95% CI, 1.05-4.55). There were no significant associations of persistent bacteremia with high vancomycin minimal inhibitory concentration, vancomycin heteroresistance, and microbiologic/genotypic characteristics of MRSA isolates. However, initial vancomycin trough level <15 mg/L was an independent risk factor for persistent MRSA bacteremia (OR, 4.25; 95% CI, 1.51-11.96) in the multivariate analysis. Clinical outcomes were significantly worse for patients with persistent bacteremia. Relapse of bacteremia and attributable mortality within 12 weeks after SAB were significantly higher in patients with persistent bacteremia than in those with resolving bacteremia (9.2% [7/76] vs. 2.4% [5/212], p = 0.02 and 21.1% [16/76] vs. 9.4% [20/212], p = 0.009, respectively). In conclusion, patients with SAB should be given early aggressive treatment strategies, including early source control and maintenance of a vancomycin trough level ≥15 mg/L, to reduce the risk of persistent bacteremia.
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Affiliation(s)
- Yong Pil Chong
- From the Department of Infectious Diseases (YPC, KHP, SHK, SOL, SHC, JHW, YSK) and Department of Laboratory Medicine (MNK), Asan Medical Center, University of Ulsan College of Medicine, Center for Antimicrobial Resistance and Microbial Genetics (SJP, HSK, ESK, JYJ, YSK), Seoul, Republic of Korea
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89
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Avent ML, Vaska VL, Rogers BA, Cheng AC, van Hal SJ, Holmes NE, Howden BP, Paterson DL. Vancomycin therapeutics and monitoring: a contemporary approach. Intern Med J 2013. [DOI: 10.1111/imj.12036] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - V. L. Vaska
- UQ Centre for Clinical Research; The University of Queensland; Brisbane; Queensland; Australia
| | - B. A. Rogers
- UQ Centre for Clinical Research; The University of Queensland; Brisbane; Queensland; Australia
| | - A. C. Cheng
- Department of Epidemiology and Preventive Medicine; Monash University; Melbourne; Victoria; Australia
| | - S. J. van Hal
- Department of Microbiology and Infectious Diseases; Royal Prince Alfred Hospital; Sydney; New South Wales; Australia
| | - N. E. Holmes
- Department of Infectious Diseases; Austin Health; Melbourne; Victoria; Australia
| | | | - D. L. Paterson
- UQ Centre for Clinical Research; The University of Queensland; Brisbane; Queensland; Australia
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90
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Leejae S, Taylor PW, Voravuthikunchai SP. Antibacterial mechanisms of rhodomyrtone against important hospital-acquired antibiotic-resistant pathogenic bacteria. J Med Microbiol 2013; 62:78-85. [DOI: 10.1099/jmm.0.049205-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Sukanlaya Leejae
- Department of Microbiology and Natural Products Research Center, Faculty of Science, Prince of Songkla University, Songkhla 90112, Thailand
| | | | - Supayang Piyawan Voravuthikunchai
- Department of Microbiology and Natural Products Research Center, Faculty of Science, Prince of Songkla University, Songkhla 90112, Thailand
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91
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Abstract
Background Drug resistance in bacterial pathogens is an increasing problem, which stimulates research. However, our understanding of drug resistance mechanisms remains incomplete. Fortunately, the fast-growing number of fully sequenced bacterial strains now enables us to develop new methods to identify mutations associated with drug resistance. Results We present a new comparative approach to identify genes and mutations that are likely to be associated with drug resistance mechanisms. In order to test the approach, we collected genotype and phenotype data of 100 fully sequenced strains of S. aureus and 10 commonly used drugs. Then, applying the method, we re-discovered the most common genetic determinants of drug resistance and identified some novel putative associations. Conclusions Firstly, the collected data may help other researchers to develop and verify similar techniques. Secondly, the proposed method is successful in identifying drug resistance determinants. Thirdly, the in-silico identified genetic mutations, which are putatively involved in drug resistance mechanisms, may increase our understanding of the drug resistance mechanisms.
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92
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Mavros MN, Tansarli GS, Vardakas KZ, Rafailidis PI, Karageorgopoulos DE, Falagas ME. Impact of vancomycin minimum inhibitory concentration on clinical outcomes of patients with vancomycin-susceptible Staphylococcus aureus infections: a meta-analysis and meta-regression. Int J Antimicrob Agents 2012; 40:496-509. [PMID: 23068600 DOI: 10.1016/j.ijantimicag.2012.07.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 07/24/2012] [Accepted: 07/27/2012] [Indexed: 12/29/2022]
Abstract
Although the vancomycin minimum inhibitory concentration (VMIC) susceptibility breakpoint for Staphylococcus aureus was recently lowered to ≤2 mg/L, it is argued that isolates in the higher levels of the susceptible range may bear adverse clinical outcomes. Clinical outcomes (all-cause mortality and treatment failure) of patients with S. aureus infections by 'high-VMIC' (conventionally defined as VMIC >1 mg/L but ≤2 mg/L) and 'low-VMIC' (VMIC≤1 mg/L) isolates were compared by performing a systematic review and meta-analysis. The effect of potential confounders was assessed by univariate meta-regression analyses. In total, 33 studies (6210 patients) were included. Most studies were retrospective (28/33), used the Etest (22/33) and referred to meticillin-resistant S. aureus (MRSA) infections (26/33) and bacteraemia (23/33). Irrespective of VMIC testing method, meticillin resistance and site of infection, the high-VMIC group had higher mortality [relative risk (RR)=1.21 (95% confidence interval 1.03-1.43); 4612 patients] and more treatment failures [RR=1.67 (1.26-2.21); 2049 patients] than the low-VMIC group. The results were not affected by the potential confounders and were reproduced in the subset of patients with MRSA infections [mortality, RR=1.19 (1.02-1.40), 2956 patients; treatment failure, RR=1.69 (1.26-2.25), 1793 patients]. In conclusion, infection by vancomycin-susceptible S. aureus with VMIC>1mg/L appears to be associated with higher mortality than VMIC≤1mg/L. Further research is warranted to verify these results and to assess the impact of VMIC on meticillin-susceptible S. aureus infections. Evaluation of alternative antimicrobial agents also appears justified.
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93
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Leonard SN. Synergy between vancomycin and nafcillin against Staphylococcus aureus in an in vitro pharmacokinetic/pharmacodynamic model. PLoS One 2012; 7:e42103. [PMID: 22848719 PMCID: PMC3404091 DOI: 10.1371/journal.pone.0042103] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Accepted: 07/02/2012] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Continued pressure from glycopeptide use has led to non-susceptible strains of Staphylococcus aureus including heterogeneously vancomycin-intermediate S. aureus (hVISA). Infections with hVISA are associated with poor patient outcomes, thus incentivizing novel treatments. Evidence suggests that vancomycin and anti-staphylococcal penicillin susceptibility are inversely related which indicates that the use of this combination may be particularly useful against methicillin-resistant S. aureus with reduced susceptibility to vancomycin, such as hVISA. The aim of this study was to evaluate the potential for synergy between vancomycin and nafcillin against hVISA. METHODS Twenty-five hVISA strains were evaluated for vancomycin and nafcillin minimum inhibitory concentration (MIC) by broth microdilution in duplicate. Potential for synergy was assessed by time-kill at 1/2x MIC in triplicate. Five strains were chosen, representing the range nafcillin MIC's available in the cohort -4, 16, 64, 128, and 256 µg/mL, and were run in an in vitro pharmacokinetic/pharmacodynamic (PK/PD) model in duplicate over 72 hours to evaluate the potential of the combination with simulated human pharmacokinetics. In addition, 4 fully glycopeptide susceptible strains of S. aureus including 2 methicillin-susceptible (MSSA) and 2 methicillin-resistant (MRSA) were run in the PK/PD model for comparison. RESULTS In the time-kill, 92% of strains (23 of 25) displayed synergy with the combination of vancomycin and nafcillin. In the PK/PD model, all five strains of hVISA showed an improvement in overall activity (P≤0.004) and organism burden at 72 hours (P≤0.001) with the combination compared to either drug alone. The combination was also successful against both MRSA and MSSA in overall activity (P≤0.009) and organism burden at 72 hours (P≤0.016), though the magnitude of the effect was diminished against MSSA. CONCLUSIONS The combination of vancomycin and nafcillin significantly improved antibacterial activity against hVISA, MRSA, and MSSA compared to either drug alone.
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Affiliation(s)
- Steven N Leonard
- School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts, United States of America.
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94
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Altering the proclivity towards daptomycin resistance in methicillin-resistant Staphylococcus aureus using combinations with other antibiotics. Antimicrob Agents Chemother 2012; 56:5046-53. [PMID: 22802248 DOI: 10.1128/aac.00502-12] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Daptomycin (DAP) is increasingly used as a part of combination therapy, particularly in complex methicillin-resistant Staphylococcus aureus (MRSA) infections. While multiple studies have reported the potential for synergy between DAP and adjunctive anti-infectives, few have examined the influence of adjunctive therapy on the emergence of DAP resistance. This study examined eight adjunctive antimicrobial combinations with DAP in vitro and the emergence of DAP resistance over time (up to 4 weeks) using clinical isolates of DAP-susceptible MRSA (MIC, 0.5 μg/ml) in which DAP resistance subsequently developed during patient therapy (MIC, 3 μg/ml). In addition to DAP susceptibility testing, selected strains were examined for phenotypic changes associated with DAP resistance, including changes to cell wall thickness (CWT) and cell membrane alterations. The addition of either oxacillin or clarithromycin in medium containing DAP significantly inhibited the development of DAP resistance through the entirety of the 4-week exposure (10- to 32-fold MIC reduction from that of DAP alone). Combinations with rifampin or fosfomycin were effective in delaying the emergence of DAP resistance through the end of week one only (week one MIC, 0.5 μg/ml; week four MIC, 24 μg/ml). Cell wall thickening was observed for all antibiotic combinations regardless of their effect on the DAP MIC (14 to 70% increase in CWT), while changes in cell membrane fluidity were variable and treatment dependent. DAP showed reduced activity against strains with DAP MICs of 1 to 12 μg/ml, but cell membrane integrity was still disrupted at concentrations achieved with doses greater than 10 mg/kg of body weight. The emergence of DAP resistance in MRSA is strongly influenced by the presence of subinhibitory concentrations of adjunctive antimicrobials. These data suggest that combining DAP with oxacillin or clarithromycin may delay the development of DAP resistance in cases requiring prolonged antibiotic therapy.
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95
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Vancomycin tolerance in methicillin-resistant Staphylococcus aureus: influence of vancomycin, daptomycin, and telavancin on differential resistance gene expression. Antimicrob Agents Chemother 2012; 56:4422-7. [PMID: 22687502 DOI: 10.1128/aac.00676-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) isolates that are susceptible to vancomycin but are tolerant to its killing effect may present a potential challenge for effective treatment. This study compared the microbiologic characteristics of clinical vancomycin-tolerant (VT-MRSA) and vancomycin-susceptible (VS-MRSA) strains using phenotypic and gene regulation studies. MRSA isolates collected from vancomycin-treated patients with bacteremia over a 5-year period were analyzed for vancomycin, daptomycin, and telavancin susceptibility, as well as accessory gene regulator (agr) group and function. Vancomycin tolerance was defined by a minimum bactericidal concentration (MBC)/minimum inhibitor concentration (MIC) ratio of ≥32 mg/liter. VT-MRSA isolates were compared to VS-MRSA isolates for differences in antimicrobial susceptibility, time-kill activity, and gene expression of key cell envelope response genes vraSR, dltA, and mprF. All 115 isolates evaluated were susceptible to vancomycin, daptomycin, and telavancin. Seven isolates (6%) were VT-MRSA. agr group II was more prevalent in isolates with vancomycin MBC/MIC ratios of ≥8. In time-kill analyses, VT-MRSA had reduced vancomycin killing, but daptomycin and telavancin activities were maintained. Significantly greater gene expression was observed in VT-MRSA after 72 h of subinhibitory antibiotic exposures. Vancomycin most notably increased vraSR expression (P = 0.002 versus VS-MRSA strains). Daptomycin and telavancin increased expression of all genes studied, most significantly mprF expression (P < 0.001). Longer durations of antibiotic exposure (72 h versus 24 h) resulted in substantial increases in gene expression in VT-MRSA. Although the clinical impact of VT-MRSA is not fully recognized, these data suggest that VT-MRSA strains, while still susceptible, have altered gene regulation to adapt to the antimicrobial effects of glyco- and lipopeptides that may emerge during prolonged durations of exposure.
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96
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Cameron DR, Ward DV, Kostoulias X, Howden BP, Moellering RC, Eliopoulos GM, Peleg AY. Serine/threonine phosphatase Stp1 contributes to reduced susceptibility to vancomycin and virulence in Staphylococcus aureus. J Infect Dis 2012; 205:1677-87. [PMID: 22492855 PMCID: PMC3415852 DOI: 10.1093/infdis/jis252] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 12/05/2011] [Indexed: 01/28/2023] Open
Abstract
The genetic mechanisms that contribute to reduced susceptibility to vancomycin in Staphylococcus aureus are complex and heterogeneous. In addition, debate is emerging as to the true effect of reduced susceptibility to vancomycin on staphylococcal virulence. To investigate this, comparative genomics was performed on a collection of vancomycin-exposed isogenic S. aureus pairs (14 strains in total). Previously described mutations were observed in genes such as vraG, agrA, yvqF, and rpoB; however, a new mechanism was identified involving a serine/threonine phosphatase, Stp1. After constructing an stp1 deletion mutant, we showed that stp1 is important in vancomycin susceptibility and cell wall biosynthesis. Gene expression studies showed that stp1 also regulates virulence genes, including a hemolysin, superantigen-like protein, and phenol-soluble modulin, and that the deletion mutant is attenuated in virulence in vivo. Stp1 provides a new link between vancomycin susceptibility and virulence in S. aureus.
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Affiliation(s)
- David R. Cameron
- Department of Microbiology, Monash University, Melbourne, Australia
| | | | - Xenia Kostoulias
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Benjamin P. Howden
- Department of Microbiology, Monash University, Melbourne, Australia
- Austin Centre for Infection Research, Department of Infectious Diseases
- Department of Microbiology, Austin Hospital
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Australia
| | - Robert C. Moellering
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center
- Harvard Medical School, Boston, Massachusetts
| | - George M. Eliopoulos
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center
- Harvard Medical School, Boston, Massachusetts
| | - Anton Y. Peleg
- Department of Microbiology, Monash University, Melbourne, Australia
- Division of Infectious Diseases, Beth Israel Deaconess Medical Center
- Department of Infectious Diseases, The Alfred Hospital, Melbourne, Australia
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97
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Relationship between vancomycin-resistant Staphylococcus aureus, vancomycin-intermediate S. aureus, high vancomycin MIC, and outcome in serious S. aureus infections. J Clin Microbiol 2012; 50:2548-52. [PMID: 22593595 DOI: 10.1128/jcm.00775-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Vancomycin has been used successfully for over 50 years for the treatment of Staphylococcus aureus infections, particularly those involving methicillin-resistant S. aureus. It has proven remarkably reliable, but its efficacy is now being questioned with the emergence of strains of S. aureus that display heteroresistance, intermediate resistance, and, occasionally, complete vancomycin resistance. More recently, an association has been established between poor outcome and infections with strains of S. aureus with an elevated vancomycin MIC within the susceptible range. This minireview summarizes the definitions, mechanisms, clinical impact, and laboratory identification of reduced vancomycin susceptibility in S. aureus and discusses practical issues for the diagnostic laboratory in testing and interpreting vancomycin susceptibility for S. aureus infections.
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98
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Park KH, Kim ES, Kim HS, Park SJ, Bang KM, Park HJ, Park SY, Moon SM, Chong YP, Kim SH, Lee SO, Choi SH, Jeong JY, Kim MN, Woo JH, Kim YS. Comparison of the clinical features, bacterial genotypes and outcomes of patients with bacteraemia due to heteroresistant vancomycin-intermediate Staphylococcus aureus and vancomycin-susceptible S. aureus. J Antimicrob Chemother 2012; 67:1843-9. [DOI: 10.1093/jac/dks131] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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99
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A novel δ-hemolysis screening method for detecting heteroresistant vancomycin-intermediate Staphylococcus aureus and vancomycin-intermediate S. aureus. J Clin Microbiol 2012; 50:1742-4. [PMID: 22403425 DOI: 10.1128/jcm.06307-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We assessed a new screening method, based on δ-hemolysin production in the presence of 6 mg/liter vancomycin, to distinguish heteroresistant vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate S. aureus (VISA) from vancomycin-susceptible S. aureus (VSSA). On 37 clinical methicillin-resistant S. aureus (MRSA) isolates, hVISA and VISA displayed no δ-hemolysis whereas VSSA displayed strong δ-hemolysis, showing 91.6% sensitivity. These data, supported by real-time reverse transcription PCR (real-time RT-PCR) highlighting an hld downregulation, i.e., VSSA>hVISA>VISA, define this new assay as a valid screening method.
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Cameron DR, Howden BP, Peleg AY. The interface between antibiotic resistance and virulence in Staphylococcus aureus and its impact upon clinical outcomes. Clin Infect Dis 2012; 53:576-82. [PMID: 21865195 DOI: 10.1093/cid/cir473] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The ability of Staphylococcus aureus to rapidly acquire antibiotic resistance in the face of antimicrobial challenge has enabled it to remain an ongoing, significant human pathogen. Mechanisms behind the evolution of resistance in S. aureus are well documented, but the effects of these phenotypes upon virulence are less clear. By exploring available clinical and experimental data, we have shown that a number of the major steps in the evolution of antibacterial resistance in S. aureus have been accompanied by alterations in virulence. This review also highlights that further experimentation is required to fully elucidate the mechanisms involved in the interface between virulence and antibiotic resistance, with the intention of identifying novel preventative or therapeutic strategies for this important human pathogen.
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Affiliation(s)
- David R Cameron
- Department of Microbiology, Monash University, Melbourne, Australia
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