51
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Szczesniak RD, Cogen JD, Rosenfeld M. Associating antimicrobial susceptibility testing with clinical outcomes in cystic fibrosis: More rigor and less frequency? J Cyst Fibros 2019; 18:159-160. [PMID: 30824378 PMCID: PMC7020339 DOI: 10.1016/j.jcf.2019.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 02/14/2019] [Accepted: 02/14/2019] [Indexed: 10/27/2022]
Affiliation(s)
- Rhonda D Szczesniak
- Division of Biostatistics & Epidemiology and Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati, United States.
| | - Jonathan D Cogen
- Division of Pulmonary and Sleep Medicine, University of Washington, Seattle Children's Hospital, United States
| | - Margaret Rosenfeld
- Division of Pulmonary and Sleep Medicine, University of Washington, Seattle Children's Hospital, United States
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Long B, Koyfman A. Urine Culture and Uncomplicated Cystitis: The Minuses Outweigh the Pluses. Ann Emerg Med 2019; 73:309-311. [DOI: 10.1016/j.annemergmed.2018.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Indexed: 11/29/2022]
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Abstract
Antimicrobial susceptibility testing is an essential tool to the veterinarian for selecting the most appropriate agent for treatment of bacterial diseases of animals. The availability of well-defined methods that incorporate the necessary quality controls coupled to clinical outcome data is foundational in providing relevant test results for clinical decisions. Since 1993, the Clinical Laboratory and Standards Institute (CLSI) Subcommittee on Veterinary Antimicrobial Susceptibility Testing (VAST) has developed specific test methods and interpretive criteria for veterinary pathogens. This information has allowed for veterinarians to more effectively treat animal diseases thereby protecting both animal welfare and human food security. Moreover, the availability of standardized test methods for veterinary pathogens has allowed for the development of antimicrobial surveillance programs to detect the emergence of resistance among veterinary pathogens. Future work by the VAST and other groups will be critical to expanding the current test methods and interpretive criteria to more pathogen-antibacterial combinations, as well as, the incorporation of genomic information for routine antimicrobial susceptibility testing in the veterinary diagnostic laboratory.
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54
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Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat Commun 2018; 9:2470. [PMID: 29941885 PMCID: PMC6018213 DOI: 10.1038/s41467-018-04926-x] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
Tolerance to antifungal drug concentrations above the minimal inhibitory concentration (MIC) is rarely quantified, and current clinical recommendations suggest it should be ignored. Here, we quantify antifungal tolerance in Candida albicans isolates as the fraction of growth above the MIC, and find that it is distinct from susceptibility/resistance. Instead, tolerance is due to the slow growth of subpopulations of cells that overcome drug stress more efficiently than the rest of the population, and correlates inversely with intracellular drug accumulation. Many adjuvant drugs used in combination with fluconazole, a widely used fungistatic drug, reduce tolerance without affecting resistance. Accordingly, in an invertebrate infection model, adjuvant combination therapy is more effective than fluconazole in treating infections with highly tolerant isolates and does not affect infections with low tolerance isolates. Furthermore, isolates recovered from immunocompetent patients with persistent candidemia display higher tolerance than isolates readily cleared by fluconazole. Thus, tolerance correlates with, and may help predict, patient responses to fluconazole therapy. The authors show that antifungal tolerance, defined as the fraction of growth of a fungal pathogen above the minimal inhibitory concentration, is due to the slow growth of subpopulations of cells that overcome drug stress, and that high tolerance is often associated with persistent infections.
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55
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Does the use of antifungal agents in agriculture and food foster polyene resistance development? A reason for concern. J Glob Antimicrob Resist 2018; 13:40-48. [DOI: 10.1016/j.jgar.2017.10.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 10/03/2017] [Accepted: 10/30/2017] [Indexed: 01/11/2023] Open
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Geddes-McAlister J, Shapiro RS. New pathogens, new tricks: emerging, drug-resistant fungal pathogens and future prospects for antifungal therapeutics. Ann N Y Acad Sci 2018; 1435:57-78. [DOI: 10.1111/nyas.13739] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/19/2018] [Accepted: 03/28/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
- Department of Proteomics and Signal Transduction; Max Planck Institute of Biochemistry; Munich Germany
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology; University of Guelph; Guelph Ontario Canada
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57
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Coates J, Park BR, Le D, Şimşek E, Chaudhry W, Kim M. Antibiotic-induced population fluctuations and stochastic clearance of bacteria. eLife 2018; 7:32976. [PMID: 29508699 PMCID: PMC5847335 DOI: 10.7554/elife.32976] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 02/15/2018] [Indexed: 01/22/2023] Open
Abstract
Effective antibiotic use that minimizes treatment failures remains a challenge. A better understanding of how bacterial populations respond to antibiotics is necessary. Previous studies of large bacterial populations established the deterministic framework of pharmacodynamics. Here, characterizing the dynamics of population extinction, we demonstrated the stochastic nature of eradicating bacteria with antibiotics. Antibiotics known to kill bacteria (bactericidal) induced population fluctuations. Thus, at high antibiotic concentrations, the dynamics of bacterial clearance were heterogeneous. At low concentrations, clearance still occurred with a non-zero probability. These striking outcomes of population fluctuations were well captured by our probabilistic model. Our model further suggested a strategy to facilitate eradication by increasing extinction probability. We experimentally tested this prediction for antibiotic-susceptible and clinically-isolated resistant bacteria. This new knowledge exposes fundamental limits in our ability to predict bacterial eradication. Additionally, it demonstrates the potential of using antibiotic concentrations that were previously deemed inefficacious to eradicate bacteria.
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Affiliation(s)
- Jessica Coates
- Microbiology and Molecular Genetics Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, United States
| | - Bo Ryoung Park
- Department of Physics, Emory University, Atlanta, United States
| | - Dai Le
- Department of Physics, Emory University, Atlanta, United States
| | - Emrah Şimşek
- Department of Physics, Emory University, Atlanta, United States
| | - Waqas Chaudhry
- Department of Physics, Emory University, Atlanta, United States
| | - Minsu Kim
- Microbiology and Molecular Genetics Graduate Program, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, United States.,Department of Physics, Emory University, Atlanta, United States.,Emory Antibiotic Resistance Center, Emory University, Atlanta, United States
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Toutain PL, Bousquet-Mélou A, Damborg P, Ferran AA, Mevius D, Pelligand L, Veldman KT, Lees P. En Route towards European Clinical Breakpoints for Veterinary Antimicrobial Susceptibility Testing: A Position Paper Explaining the VetCAST Approach. Front Microbiol 2017; 8:2344. [PMID: 29326661 PMCID: PMC5736858 DOI: 10.3389/fmicb.2017.02344] [Citation(s) in RCA: 108] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/15/2017] [Indexed: 01/05/2023] Open
Abstract
VetCAST is the EUCAST sub-committee for Veterinary Antimicrobial Susceptibility Testing. Its remit is to define clinical breakpoints (CBPs) for antimicrobial drugs (AMDs) used in veterinary medicine in Europe. This position paper outlines the procedures and reviews scientific options to solve challenges for the determination of specific CBPs for animal species, drug substances and disease conditions. VetCAST will adopt EUCAST approaches: the initial step will be data assessment; then procedures for decisions on the CBP; and finally the release of recommendations for CBP implementation. The principal challenges anticipated by VetCAST are those associated with the differing modalities of AMD administration, including mass medication, specific long-acting product formulations or local administration. Specific challenges comprise mastitis treatment in dairy cattle, the range of species and within species breed considerations and several other variable factors not relevant to human medicine. Each CBP will be based on consideration of: (i) an epidemiological cut-off value (ECOFF) - the highest MIC that defines the upper end of the wild-type MIC distribution; (ii) a PK/PD breakpoint obtained from pre-clinical pharmacokinetic data [this PK/PD break-point is the highest possible MIC for which a given percentage of animals in the target population achieves a critical value for the selected PK/PD index (fAUC/MIC or fT > MIC)] and (iii) when possible, a clinical cut-off, that is the relationship between MIC and clinical cure. For the latter, VetCAST acknowledges the paucity of such data in veterinary medicine. When a CBP cannot be established, VetCAST will recommend use of ECOFF as surrogate. For decision steps, VetCAST will follow EUCAST procedures involving transparency, consensus and independence. VetCAST will ensure freely available dissemination of information, concerning standards, guidelines, ECOFF, PK/PD breakpoints, CBPs and other relevant information for AST implementation. Finally, after establishing a CBP, VetCAST will promulgate expert comments and/or recommendations associated with CBPs to facilitate their sound implementation in a clinical setting.
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Affiliation(s)
- Pierre-Louis Toutain
- UMR 1331 Toxalim, INRA, ENVT, Toulouse, France
- The Royal Veterinary College, University of London, London, United Kingdom
| | | | - Peter Damborg
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Dik Mevius
- Wageningen Bioveterinary Research, Lelystad, Netherlands
| | - Ludovic Pelligand
- The Royal Veterinary College, University of London, London, United Kingdom
| | - Kees T. Veldman
- National Reference Laboratory on Antimicrobial Resistance in Animals, Lelystad, Netherlands
| | - Peter Lees
- The Royal Veterinary College, University of London, London, United Kingdom
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59
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Interaction of Antibiotics with Innate Host Defense Factors against Salmonella enterica Serotype Newport. mSphere 2017; 2:mSphere00410-17. [PMID: 29242830 PMCID: PMC5717323 DOI: 10.1128/msphere.00410-17] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 11/05/2017] [Indexed: 12/11/2022] Open
Abstract
It is becoming increasingly understood that the current paradigms of in vitro antimicrobial susceptibility testing may have significant shortcomings in predicting activity in vivo. This study evaluated the activity of several antibiotics alone and in combination against clinical isolates of Salmonella enterica serotype Newport (meningitis case) utilizing both conventional and physiological media. In addition, the interactions of these antibiotics with components of the innate immune system were evaluated. Azithromycin, which has performed quite well clinically despite high MICs in conventional media, was shown to be more active in physiological media and to enhance innate immune system killing. Alternatively, chloramphenicol did not show enhanced immune system killing, paralleling its inferior clinical performance to other antibiotics that have been used to treat Salmonella meningitis. These findings are important additions to the building understanding of current in vitro antimicrobial assay limitations that hopefully will amount to future improvements in these assays to better predict clinical efficacy and activity in vivo. This study examines the pharmacodynamics of antimicrobials that are used to treat Salmonella with each other and with key components of the innate immune system. Antimicrobial synergy was assessed using time-kill and checkerboard assays. Antimicrobial interactions with innate immunity were studied by employing cathelicidin LL-37, whole-blood, and neutrophil killing assays. Ceftriaxone and ciprofloxacin were found to be synergistic in vitro against Salmonella enterica serotype Newport. Ceftriaxone, ciprofloxacin, and azithromycin each demonstrated synergy with the human cathelicidin defense peptide LL-37 in killing Salmonella. Exposure of Salmonella to sub-MICs of ceftriaxone resulted in enhanced susceptibility to LL-37, whole blood, and neutrophil killing. The activity of antibiotics in vivo against Salmonella may be underestimated in bacteriologic media lacking components of innate immunity. The pharmacodynamic interactions of antibiotics used to treat Salmonella with each other and with components of innate immunity warrant further study in light of recent findings showing in vivo selection of antimicrobial resistance by single agents in this pathogen. IMPORTANCE It is becoming increasingly understood that the current paradigms of in vitro antimicrobial susceptibility testing may have significant shortcomings in predicting activity in vivo. This study evaluated the activity of several antibiotics alone and in combination against clinical isolates of Salmonella enterica serotype Newport (meningitis case) utilizing both conventional and physiological media. In addition, the interactions of these antibiotics with components of the innate immune system were evaluated. Azithromycin, which has performed quite well clinically despite high MICs in conventional media, was shown to be more active in physiological media and to enhance innate immune system killing. Alternatively, chloramphenicol did not show enhanced immune system killing, paralleling its inferior clinical performance to other antibiotics that have been used to treat Salmonella meningitis. These findings are important additions to the building understanding of current in vitro antimicrobial assay limitations that hopefully will amount to future improvements in these assays to better predict clinical efficacy and activity in vivo.
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60
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Microfluidics for Combating Antimicrobial Resistance. Trends Biotechnol 2017; 35:1129-1139. [DOI: 10.1016/j.tibtech.2017.07.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/12/2017] [Accepted: 07/14/2017] [Indexed: 01/09/2023]
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61
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Abstract
Antimicrobial resistance constitutes a global burden and is one of the major threats to public health. Although the emergence of resistant microorganisms is a natural phenomenon, the overuse or inappropriate use of antimicrobials has had a great effect on resistance evolution. Rapid diagnostic tests that identify drug-resistant bacteria, determine antimicrobial susceptibility and distinguish viral from bacterial infections can guide effective treatment strategies. Moreover, rapid diagnostic tests could facilitate epidemiological surveillance, as emerging resistant infectious agents and transmission can be monitored. In this Viewpoint article, several experts in the field discuss the drawbacks of current diagnostic methods that are used to identify antimicrobial resistance, novel diagnostic strategies and how such rapid tests can inform drug development and the surveillance of resistance evolution.
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Affiliation(s)
- Carey-Ann D Burnham
- Department of Pathology &Immunology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8118, St. Louis, Missouri 63110, USA
| | - Jennifer Leeds
- Novartis Institutes for Biomedical Research, Inc., Infectious Diseases Area, 5300 Chiron Way, Emeryville, California 94608, USA
| | - Patrice Nordmann
- Medical and Molecular Microbiology Department of Medicine, INSERM European Laboratory (French National Institute for Health and Medical Research, Paris), Natural Reference Center for Emerging Antibiotic Resistance, University of Fribourg, Chemin du Musée 18, 1700 Fribourg, Switzerland
| | - Justin O'Grady
- Norwich Medical School, Faculty of Medicine and Health Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jean Patel
- Antibiotic Resistance Coordination and Strategy Unit, National Center for Emerging Zoonotic and Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, Georgia 30329-4027, USA
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62
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Brennan-Krohn T, Smith KP, Kirby JE. The Poisoned Well: Enhancing the Predictive Value of Antimicrobial Susceptibility Testing in the Era of Multidrug Resistance. J Clin Microbiol 2017; 55:2304-2308. [PMID: 28468856 PMCID: PMC5527407 DOI: 10.1128/jcm.00511-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial susceptibility testing (AST) is a fundamental mission of the clinical microbiology laboratory. Reference AST methods are based on bacterial growth in antibiotic doubling dilution series, which means that any error in the reference method inherently represents at least a 2-fold difference. We describe the origins of current AST reference methodology, highlight the sources of AST variability, and propose ideas for improving AST predictive power.
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Affiliation(s)
- Thea Brennan-Krohn
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massaschusetts, USA
- Division of Infectious Diseases, Boston Children's Hospital, Boston, Massaschusetts, USA
| | - Kenneth P Smith
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massaschusetts, USA
| | - James E Kirby
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massaschusetts, USA
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63
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Guardabassi L, Damborg P, Stamm I, Kopp PA, Broens EM, Toutain PL. Diagnostic microbiology in veterinary dermatology: present and future. Vet Dermatol 2017; 28:146-e30. [PMID: 28133869 DOI: 10.1111/vde.12414] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND The microbiology laboratory can be perceived as a service provider rather than an integral part of the healthcare team. OBJECTIVES The aim of this review is to discuss the current challenges of providing a state-of-the-art diagnostic veterinary microbiology service including the identification (ID) and antimicrobial susceptibility testing (AST) of key pathogens in veterinary dermatology. METHODS The Study Group for Veterinary Microbiology (ESGVM) of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) identified scientific, technological, educational and regulatory issues impacting the predictive value of AST and the quality of the service offered by microbiology laboratories. RESULTS The advent of mass spectrometry has significantly reduced the time required for ID of key pathogens such as Staphylococcus pseudintermedius. However, the turnaround time for validated AST methods has remained unchanged for many years. Beyond scientific and technological constraints, AST methods are not harmonized and clinical breakpoints for some antimicrobial drugs are either missing or inadequate. Small laboratories, including in-clinic laboratories, are usually not adequately equipped to run up-to-date clinical microbiologic diagnostic tests. CONCLUSIONS AND CLINICAL IMPORTANCE ESGVM recommends the use of laboratories employing mass spectrometry for ID and broth micro-dilution for AST, and offering assistance by expert microbiologists on pre- and post-analytical issues. Setting general standards for veterinary clinical microbiology, promoting antimicrobial stewardship, and the development of new, validated and rapid diagnostic methods, especially for AST, are among the missions of ESGVM.
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Affiliation(s)
- Luca Guardabassi
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St Kitts and Nevis, West Indies.,Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg, Denmark
| | - Peter Damborg
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg, Denmark
| | - Ivonne Stamm
- IDEXX Vet·Med·Labor, Moerikestrasse 28/3, D-71636, Ludwigsburg, Germany
| | - Peter A Kopp
- IDEXX Vet·Med·Labor, Moerikestrasse 28/3, D-71636, Ludwigsburg, Germany
| | - Els M Broens
- Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL, Utrecht, The Netherlands
| | - Pierre-Louis Toutain
- UMR 1331 Toxalim INRA/INP, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, BP 87614, 31076, Toulouse Cedex 3, France
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64
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Liu Z, Sun H, Ren K. A Multiplexed, Gradient-Based, Full-Hydrogel Microfluidic Platform for Rapid, High-Throughput Antimicrobial Susceptibility Testing. Chempluschem 2017; 82:792-801. [PMID: 31961536 DOI: 10.1002/cplu.201600654] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/25/2017] [Indexed: 11/07/2022]
Abstract
Antimicrobial resistance has become an immediate threat to modern healthcare systems as it continues to spread across the globe. As development of novel antibiotics stalls, preserving the effectiveness of existing agents has become a priority. One of the major driving forces behind antimicrobial resistance is the misuse and overuse of antibiotics, often a result of data on the susceptibility of pathogens not being obtained in a convenient and timely manner, a need that conventional antimicrobial susceptibility testing struggles to meet. Here, a hydrogel microfluidic platform is reported for antimicrobial susceptibility testing purposes, capable of handling real samples and yielding results within 2.5 h of culture. By using a multiplayer design with channels crossing overhead of each other, multiple experiments, either one- or two-dimensional, can be staged on the same device. Bacteria grown on the surface of the hydrogel can be easily visualized with standard Gram staining after being transferred onto a glass slide. Coupled with software-based image analysis, the system can yield a variety of useful information on bacterial susceptibility and the effects of drugs, such as minimum inhibitory concentration and morphological changes in bacteria, either individually or in combination. Compared to conventional testing methods, this system requires less labor, reagents, and equipment to operate, and has significantly higher speed and efficiency.
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Affiliation(s)
- Zhengzhi Liu
- Department of Chemistry, Hong Kong Baptist University, Waterloo Rd, Kowloon, Hong Kong, P. R China
| | - Han Sun
- Department of Chemistry, Hong Kong Baptist University, Waterloo Rd, Kowloon, Hong Kong, P. R China
| | - Kangning Ren
- Department of Chemistry, Hong Kong Baptist University, Waterloo Rd, Kowloon, Hong Kong, P. R China.,State Key Laboratory of Environmental and Biological Analysis, Hong Kong Baptist University, Waterloo Rd, Kowloon, Hong Kong, P. R China.,Institute of Research and Continuing Education, Hong Kong Baptist University, Shenzhen, P. R China
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65
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Ersoy SC, Heithoff DM, Barnes L, Tripp GK, House JK, Marth JD, Smith JW, Mahan MJ. Correcting a Fundamental Flaw in the Paradigm for Antimicrobial Susceptibility Testing. EBioMedicine 2017; 20:173-181. [PMID: 28579300 PMCID: PMC5478264 DOI: 10.1016/j.ebiom.2017.05.026] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/20/2017] [Accepted: 05/23/2017] [Indexed: 12/25/2022] Open
Abstract
The emergence and prevalence of antibiotic-resistant bacteria are an increasing cause of death worldwide, resulting in a global ‘call to action’ to avoid receding into an era lacking effective antibiotics. Despite the urgency, the healthcare industry still relies on a single in vitro bioassay to determine antibiotic efficacy. This assay fails to incorporate environmental factors normally present during host-pathogen interactions in vivo that significantly impact antibiotic efficacy. Here we report that standard antimicrobial susceptibility testing (AST) failed to detect antibiotics that are in fact effective in vivo; and frequently identified antibiotics that were instead ineffective as further confirmed in mouse models of infection and sepsis. Notably, AST performed in media mimicking host environments succeeded in identifying specific antibiotics that were effective in bacterial clearance and host survival, even though these same antibiotics failed in results using standard test media. Similarly, our revised media further identified antibiotics that were ineffective in vivo despite passing the AST standard for clinical use. Supplementation of AST medium with sodium bicarbonate, an abundant in vivo molecule that stimulates global changes in bacterial structure and gene expression, was found to be an important factor improving the predictive value of AST in the assignment of appropriate therapy. These findings have the potential to improve the means by which antibiotics are developed, tested, and prescribed. Standard antimicrobial susceptibility testing (AST) is fundamentally flawed because it is based largely on in vitro efficacy. AST performed under conditions that mimic natural infections improves the assignment of appropriate antibiotic therapy. In vivo altered susceptibility (IVAS) provides a new paradigm for drug discovery and therapeutic intervention.
Drug testing often excludes potent antibiotics for the treatment of bacterial infections, while frequently identifying antibiotics that are ineffective. However, drug testing under conditions that mimic natural infections succeeded in identifying effective antibiotics, even though these same antibiotics failed standard tests. This work suggests that standard drug-testing may be hindering patient treatment and slowing the process of discovery of new, effective, and safe antibiotics because it disqualifies effective compounds. These findings call for an overhaul of standardized drug testing which hasn't changed in > 50 years.
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Affiliation(s)
- Selvi C Ersoy
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Douglas M Heithoff
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA
| | - Lucien Barnes
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - Geneva K Tripp
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA
| | - John K House
- University of Sydney, Faculty of Veterinary Science, Camden, New South Wales, Australia
| | - Jamey D Marth
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA; Sanford Burnham Prebys Medical Discovery Institute, Cancer Research Center, La Jolla, CA 92037, USA
| | - Jeffrey W Smith
- Sanford Burnham Prebys Medical Discovery Institute, Cancer Research Center, La Jolla, CA 92037, USA
| | - Michael J Mahan
- Dept. of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106, USA; Center for Nanomedicine, University of California, Santa Barbara, CA 93106, USA.
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66
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Classical β-Lactamase Inhibitors Potentiate the Activity of Daptomycin against Methicillin-Resistant Staphylococcus aureus and Colistin against Acinetobacter baumannii. Antimicrob Agents Chemother 2017; 61:AAC.01745-16. [PMID: 27872080 PMCID: PMC5278754 DOI: 10.1128/aac.01745-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 11/14/2016] [Indexed: 01/01/2023] Open
Abstract
We asked whether beta-lactamase inhibitors (BLIs) increased the activity of daptomycin (DAP) against methicillin-resistant Staphylococcus aureus (MRSA), the peptide antibiotic colistin (COL) against the emerging Gram-negative nosocomial pathogen Acinetobacter baumannii, and the human host defense peptide cathelicidin LL37 against either pathogen. DAP and LL37 kill curves were performed with or without BLIs against MRSA, vancomycin-intermediate S. aureus (VISA), and heterogeneous VISA (hVISA). COL and LL37 kill curves were performed against A. baumannii. Boron-dipyrromethene (BODIPY)-labeled DAP binding to MRSA grown with the BLI tazobactam (TAZ) was assessed microscopically. The combination of COL plus TAZ was studied in a murine model of A. baumannii pneumonia. TAZ alone lacked in vitro activity against MRSA or A. baumannii. The addition of TAZ to DAP resulted in a 2- to 5-log10 reduction in recoverable MRSA CFU at 24 h compared to the recoverable CFU with DAP alone. TAZ plus COL showed synergy by kill curves for 4 of 5 strains of A. baumannii tested. Growth with 20 mg/liter TAZ resulted in 2- to 2.5-fold increases in the intensity of BODIPY-DAP binding to MRSA and hVISA strains. TAZ significantly increased the killing of MRSA and A. baumannii by LL37 in vitro. TAZ increased the activity of COL in a murine model of A. baumannii pneumonia. Classical BLIs demonstrate synergy with peptide antibiotics. Since BLIs have scant antimicrobial activity on their own and are thus not expected to increase selective pressure toward antibiotic resistance, their use in combination with peptide antibiotics warrants further study.
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67
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Building a Personalized Cancer Treatment System. J Med Syst 2016; 41:28. [PMID: 28028763 DOI: 10.1007/s10916-016-0678-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 12/11/2016] [Indexed: 10/20/2022]
Abstract
This paper reports the process by which a personalized cancer treatment system was built, following a user-centered approach. We give some background on personalized cancer treatment, the particular tumor chemosensitivity assay supported by the system, as well as some quality and legal issues related to such health systems. We describe how Contextual Design was applied when building the system. Contextual design is a user-centered design technique involving seven steps. We also provide some details about the system implementation. Finally, we explain how the Think-Aloud protocol and Heuristic Evaluation methods were used to evaluate the system and report its results. A qualitative assessment from the users perspective is also provided. Results from the heuristic evaluation indicate that only one of ten heuristics was missing from the system, while five were partially covered and four were fully covered.
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68
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Popejoy MW, Paterson DL, Cloutier D, Huntington JA, Miller B, Bliss CA, Steenbergen JN, Hershberger E, Umeh O, Kaye KS. Efficacy of ceftolozane/tazobactam against urinary tract and intra-abdominal infections caused by ESBL-producing
Escherichia coli
and
Klebsiella pneumoniae
: a pooled analysis of Phase 3 clinical trials. J Antimicrob Chemother 2016; 72:268-272. [DOI: 10.1093/jac/dkw374] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 08/05/2016] [Accepted: 08/10/2016] [Indexed: 11/14/2022] Open
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70
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An infectious disease and pharmacokinetic perspective on oral antibiotic treatment of uncomplicated urinary tract infections due to multidrug-resistant Gram-negative uropathogens: the importance of urinary antibiotic concentrations and urinary pH. Eur J Clin Microbiol Infect Dis 2016; 35:521-6. [DOI: 10.1007/s10096-016-2577-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 01/04/2016] [Indexed: 10/22/2022]
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71
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Ormerod KL, George NM, Fraser JA, Wainwright C, Hugenholtz P. Comparative genomics of non-pseudomonal bacterial species colonising paediatric cystic fibrosis patients. PeerJ 2015; 3:e1223. [PMID: 26401445 PMCID: PMC4579023 DOI: 10.7717/peerj.1223] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/10/2015] [Indexed: 12/16/2022] Open
Abstract
The genetic disorder cystic fibrosis is a life-limiting condition affecting ∼70,000 people worldwide. Targeted, early, treatment of the dominant infecting species, Pseudomonas aeruginosa, has improved patient outcomes; however, there is concern that other species are now stepping in to take its place. In addition, the necessarily long-term antibiotic therapy received by these patients may be providing a suitable environment for the emergence of antibiotic resistance. To investigate these issues, we employed whole-genome sequencing of 28 non-Pseudomonas bacterial strains isolated from three paediatric patients. We did not find any trend of increasing antibiotic resistance (either by mutation or lateral gene transfer) in these isolates in comparison with other examples of the same species. In addition, each isolate contained a virulence gene repertoire that was similar to other examples of the relevant species. These results support the impaired clearance of the CF lung not demanding extensive virulence for survival in this habitat. By analysing serial isolates of the same species we uncovered several examples of strain persistence. The same strain of Staphylococcus aureus persisted for nearly a year, despite administration of antibiotics to which it was shown to be sensitive. This is consistent with previous studies showing antibiotic therapy to be inadequate in cystic fibrosis patients, which may also explain the lack of increasing antibiotic resistance over time. Serial isolates of two naturally multi-drug resistant organisms, Achromobacter xylosoxidans and Stenotrophomonas maltophilia, revealed that while all S. maltophilia strains were unique, A. xylosoxidans persisted for nearly five years, making this a species of particular concern. The data generated by this study will assist in developing an understanding of the non-Pseudomonas species associated with cystic fibrosis.
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Affiliation(s)
- Kate L. Ormerod
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Narelle M. George
- Health Support Queensland, Department of Health, Queensland Government, Herston, Queensland, Australia
| | - James A. Fraser
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Claire Wainwright
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia
- Department of Respiratory and Sleep Medicine, Lady Cilento Children’s Hospital, South Brisbane, Queensland, Australia
- Queensland Children’s Medical Research Insitute, Herston, Queensland, Australia
| | - Philip Hugenholtz
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
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72
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Grau S, Lozano V, Valladares A, Cavanillas R, Xie Y, Nocea G. Impact of a Dynamic Microbiological Environment on the Clinical Efficacy of Ertapenem and Piperacillin/Tazobactam in the Treatment of Complicated Community-Acquired Intra-Abdominal Infection in Spain: A Cost-Consequence Analysis. APPLIED HEALTH ECONOMICS AND HEALTH POLICY 2015; 13:369-379. [PMID: 25761545 DOI: 10.1007/s40258-015-0162-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
BACKGROUND AND OBJECTIVE The microbial susceptibility of many antibiotics has been affected by prescribing patterns and their extensive use. The purpose of this evaluation was to assess how these changes could affect the initial efficacy of ertapenem and piperacillin/tazobactam in the treatment of complicated intra-abdominal infections (IAIs) acquired in the community and the potential consequences this may have in healthcare costs in Spain. METHODS The Initial efficacy of ertapenem and piperacillin/tazobactam for patients with APACHE (Acute Physiology and Chronic Health Evaluation) II scores <10 was extracted from a multicenter randomized study and were combined with the current microbial susceptibilities obtained from the SMART study, a multinational surveillance program. Country-specific pathogens distribution was extracted from a national study in patients with community-acquired IAI. The estimated effectiveness was used in a decision-analytic model to compare total costs between ertapenem and piperacillin/tazobactam in the treatment of complicated IAI. The model performs extensive one-way and probabilistic sensitivity analyses. RESULTS The model suggested a savings of €209 (year 2012 values) per patient when complicated IAIs acquired in the community (APACHE II <10) were treated with ertapenem instead of piperacillin/tazobactam. One-way sensitivity analyses showed length of stay as the key driver parameter. Further analysis of this parameter and probabilistic sensitivity analysis confirmed the robustness of our evaluation, with a 58% likelihood of ertapenem being dominant. CONCLUSIONS Ertapenem appears to be a cost-saving strategy over piperacillin/tazobactam for the treatment of patients with complicated IAIs acquired in the community in Spain.
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Affiliation(s)
- Santiago Grau
- Hospital del Mar, Passeig Marítim 25-29, 08003, Barcelona, Spain,
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73
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Thirty-minute screening of antibiotic resistance genes in bacterial isolates with minimal sample preparation in static self-dispensing 64 and 384 assay cards. Appl Microbiol Biotechnol 2015; 99:7711-22. [PMID: 26227406 PMCID: PMC4543423 DOI: 10.1007/s00253-015-6774-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 06/04/2015] [Accepted: 06/17/2015] [Indexed: 01/23/2023]
Abstract
In a clinical setting, molecular assays such as polymerase chain reaction offer a rapid means to infer or confirm identity and therapeutic decisions. Accordingly, a number of molecular assays targeting identity and antibiotic resistance (AR) genes have been developed; however, these methods can be technically complex and relatively expensive. Herein, we describe a diagnostic concept utilizing isothermal amplification technology with non-purified heat-lysed cells and self-dispensing cards for testing multiple primers in parallel. This proof-of-concept study, performed with Staphylococcus aureus isolates and associated AR genes, was compared with culture-based susceptibility and quantitative PCR (qPCR). Results demonstrate reduced sample processing steps resulting in a turnaround time (starting from bacterial culture to ending in the antibiotic resistance gene profile) in less than 30 min. For antibiotics tested in which an associated AR gene was targeted on the Gene-Z card, 69 % (18/26) of culture-based resistance events were positive for related AR genes. A comparison of loop-mediated isothermal amplification (LAMP) and qPCR assays targeting the same antibiotic resistance genes showed a 98.2 % agreement in terms of presence and absence calls. Identity-based discrepancies between conventional (phenotypic) and molecular (genotypic) results were further resolved, and we were able to demonstrate higher accuracy in identification with the molecular analysis.
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74
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Labreche MJ, Graber CJ, Nguyen HM. Recent Updates on the Role of Pharmacokinetics-pharmacodynamics in Antimicrobial Susceptibility Testing as Applied to Clinical Practice. Clin Infect Dis 2015; 61:1446-52. [PMID: 26105168 DOI: 10.1093/cid/civ498] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/13/2015] [Indexed: 12/23/2022] Open
Abstract
Given current challenges in antimicrobial resistance and drug development, infectious diseases clinicians must rely on their own ingenuity to effectively treat infections while preserving the current antimicrobial armamentarium. An understanding of pharmacokinetics (PK), pharmacodynamics (PD), antimicrobial susceptibility testing (AST), and how these concepts relate, is essential to this task. In this review, we discuss how and why PK-PD impacts AST and the way infectious diseases are being treated, with a particular focus on vancomycin for methicillin-resistant Staphylococcus aureus, penicillin for Streptococcus pneumoniae, and an update on cephalosporins for Enterobacteriaceae. Finally, we address how new ideas to exploit PK-PD can promote innovative study design and bring about more rapid regulatory review of new antimicrobials.
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Affiliation(s)
| | - Christopher J Graber
- Infectious Diseases Section, VA Greater Los Angeles Healthcare System and the David Geffen School of Medicine at the University of California
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75
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Stein C, Makarewicz O, Bohnert JA, Pfeifer Y, Kesselmeier M, Hagel S, Pletz MW. Three Dimensional Checkerboard Synergy Analysis of Colistin, Meropenem, Tigecycline against Multidrug-Resistant Clinical Klebsiella pneumonia Isolates. PLoS One 2015; 10:e0126479. [PMID: 26067824 PMCID: PMC4465894 DOI: 10.1371/journal.pone.0126479] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/03/2015] [Indexed: 12/16/2022] Open
Abstract
The spread of carbapenem-non-susceptible Klebsiella pneumoniae strains bearing different resistance determinants is a rising problem worldwide. Especially infections with KPC (Klebsiella pneumoniae carbapenemase) - producers are associated with high mortality rates due to limited treatment options. Recent clinical studies of KPC-blood stream infections revealed that colistin-based combination therapy with a carbapenem and/or tigecycline was associated with significantly decreased mortality rates when compared to colistin monotherapy. However, it remains unclear if these observations can be transferred to K. pneumoniae harboring other mechanisms of carbapenem resistance. A three-dimensional synergy analysis was performed to evaluate the benefits of a triple combination with meropenem, tigecycline and colistin against 20 K. pneumoniae isolates harboring different β-lactamases. To examine the mechanism behind the clinically observed synergistic effect, efflux properties and outer membrane porin (Omp) genes (ompK35 and ompK36) were also analyzed. Synergism was found for colistin-based double combinations for strains exhibiting high minimal inhibition concentrations against all of the three antibiotics. Adding a third antibiotic did not result in further increased synergistic effect in these strains. Antagonism did not occur. These results support the idea that colistin-based double combinations might be sufficient and the most effective combination partner for colistin should be chosen according to its MIC.
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Affiliation(s)
- Claudia Stein
- Center for Infectious Diseases and Infection Control, Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
- * E-mail:
| | - Oliwia Makarewicz
- Center for Infectious Diseases and Infection Control, Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
| | - Jürgen A. Bohnert
- Institute of Medical Microbiology, Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
| | - Yvonne Pfeifer
- Nosocomial Pathogens and Antibiotic Resistance, Robert Koch Institute, Burgstrasse 37, D-8855, Wernigerode, Germany
| | - Miriam Kesselmeier
- Clinical Epidemiology, Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
| | - Stefan Hagel
- Center for Infectious Diseases and Infection Control, Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
| | - Mathias W. Pletz
- Center for Infectious Diseases and Infection Control, Jena University Hospital, Erlanger Allee 101, D-07747, Jena, Germany
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76
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Using Individual Animal Susceptibility Test Results in Bovine Practice. Vet Clin North Am Food Anim Pract 2015; 31:163-74, vii. [DOI: 10.1016/j.cvfa.2014.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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77
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Lubbers BV, Turnidge J. Antimicrobial susceptibility testing for bovine respiratory disease: Getting more from diagnostic results. Vet J 2015; 203:149-54. [DOI: 10.1016/j.tvjl.2014.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 09/25/2014] [Accepted: 12/09/2014] [Indexed: 12/23/2022]
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78
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Pyörälä S, Taponen J, Katila T. Use of Antimicrobials in the Treatment of Reproductive Diseases in Cattle and Horses. Reprod Domest Anim 2014; 49 Suppl 3:16-26. [DOI: 10.1111/rda.12324] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/25/2014] [Indexed: 01/10/2023]
Affiliation(s)
- S Pyörälä
- Department of Production Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Saarentaus Finland
| | - J Taponen
- Department of Production Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Saarentaus Finland
| | - T Katila
- Department of Production Animal Medicine; Faculty of Veterinary Medicine; University of Helsinki; Saarentaus Finland
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79
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Zhanel GG, Wolter KD, Calciu C, Hogan P, Low DE, Weiss K, Karlowsky JA. Clinical cure rates in subjects treated with azithromycin for community-acquired respiratory tract infections caused by azithromycin-susceptible or azithromycin-resistant Streptococcus pneumoniae: analysis of Phase 3 clinical trial data. J Antimicrob Chemother 2014; 69:2835-40. [PMID: 24920652 DOI: 10.1093/jac/dku207] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Community-acquired respiratory tract infections (CARTI) are commonly caused by Streptococcus pneumoniae (SPN) and empirically treated with azithromycin. This study assessed clinical cure rates in azithromycin-treated subjects with CARTI caused by azithromycin-susceptible (Azi-S) or azithromycin-resistant (Azi-R) SPN. METHODS 1127 subjects with CARTI (402 acute otitis media, 309 community-acquired pneumonia, 255 acute bacterial exacerbations of chronic bronchitis and 161 acute bacterial sinusitis) in 13 Phase 3 clinical trials (1993-2007) had a confirmed pathogen, received azithromycin and were assessed for clinical cure/failure. 34.4% of subjects (388/1127) had a positive culture for SPN; 33.4% (376/1127) had Azi-S or Azi-R SPN. RESULTS 28.9% (112/388) of subjects with SPN had Azi-R SPN: 35.7% (40/112) were low-level Azi-R SPN (LLAR; MIC 2-8 mg/L), while 64.3% (72/112) were high-level Azi-R SPN (HLAR; MIC ≥16 mg/L). Among Azi-S and Azi-R SPN CARTI subjects, clinical cure rates were: 86.2% (324/376) overall; 89.4% (236/264) for subjects with Azi-S SPN; 78.6% (88/112) for subjects with Azi-R SPN (P = 0.003, versus Azi-S); 77.5% (31/40) for subjects with LLAR SPN (P < 0.001); and 79.2% (57/72) for subjects with HLAR SPN (P = 0.122). CONCLUSIONS Clinical cure rates in CARTI subjects treated with azithromycin were higher for Azi-S SPN (89.4%) versus Azi-R SPN (78.6%; P = 0.003). However, cure rates were not different for subjects infected with LLAR-SPN versus HLAR-SPN. At the observed prevalence of Azi-R SPN of 28.9%, an additional 3.1 clinical failures would be predicted, as a consequence of azithromycin resistance (LLAR and HLAR), per 100 subjects treated empirically with azithromycin.
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Affiliation(s)
- George G Zhanel
- Department of Medical Microbiology and Infectious Diseases, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
| | - Kevin D Wolter
- Established Products Clinical Development, Pfizer Inc., New York, NY, USA
| | | | - Patricia Hogan
- Specialty Care Business Unit, Pfizer Inc., New York, NY, USA
| | - Donald E Low
- Department of Microbiology, Mount Sinai Hospital, Toronto, Canada
| | - Karl Weiss
- Maisonneuve-Rosemont Hospital, Faculty of Medicine, University of Montreal, Montreal, Canada
| | - James A Karlowsky
- Department of Medical Microbiology and Infectious Diseases, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Abstract
Determining if a nonhealing wound is infected can be difficult. The surface of a wound is not sterile and can be colonized with numerous commensal, environmental, and potentially pathogenic microorganisms. Different types of wounds have various clinical presentations, with some signs and symptoms more likely to be present than others depending on the type and location of the wound. Clinicians often order microbiology wound cultures to assist in determining if a nonhealing wound is infected. This minireview briefly summarizes the clinical microbiology of wound cultures, with an emphasis on the history and utility (or lack thereof) of the quantitative wound culture.
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81
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Treatment failure and miltefosine susceptibility in dermal leishmaniasis caused by Leishmania subgenus Viannia species. Antimicrob Agents Chemother 2013; 58:144-52. [PMID: 24145529 DOI: 10.1128/aac.01023-13] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Treatment failure and parasite drug susceptibility in dermal leishmaniasis caused by Leishmania (Viannia) species are poorly understood. Prospective evaluation of drug susceptibility of strains isolated from individual patients before drug exposure and at clinical failure allows intrinsic and acquired differences in susceptibility to be discerned and analyzed. To determine whether intrinsic susceptibility or loss of susceptibility to miltefosine contributed to treatment failure, we evaluated the miltefosine susceptibility of intracellular amastigotes and promastigotes of six Leishmania (Viannia) braziliensis and six Leishmania (Viannia) panamensis strains isolated sequentially, at diagnosis and treatment failure, from two children and four adults ≥55 years old with concurrent conditions. Four patients presented only cutaneous lesions, one had mucosal disease, and one had disseminated mucocutaneous disease. Expression of the Leishmania drug transporter genes abca2, abca3, abcc2, abcc3, abcg4, abcg6, and LbMT was evaluated by quantitative reverse transcription-PCR (qRT-PCR). Intracellular amastigotes (median 50% effective concentration [EC50], 10.7 μmol/liter) were more susceptible to miltefosine than promastigotes (median EC50, 55.3 μmol/liter) (P < 0.0001). Loss of susceptibility at failure, demonstrated by a miltefosine EC50 of >32 μmol/liter (the upper limit of intracellular amastigote assay), occurred in L. panamensis infection in a child and in L. braziliensis infection in an adult and was accompanied by decreased expression of the miltefosine transporter LbMT (LbMT/β-tubulin, 0.42- to 0.26-fold [P = 0.039] and 0.70- to 0.57-fold [P = 0.009], respectively). LbMT gene polymorphisms were not associated with susceptibility phenotype. Leishmania ABCA3 transporter expression was inversely correlated with miltefosine susceptibility (r = -0.605; P = 0.037). Loss of susceptibility is one of multiple factors involved in failure of miltefosine treatment in dermal leishmaniasis.
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82
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De Briyne N, Atkinson J, Pokludová L, Borriello SP, Price S. Factors influencing antibiotic prescribing habits and use of sensitivity testing amongst veterinarians in Europe. Vet Rec 2013; 173:475. [PMID: 24068699 PMCID: PMC3841786 DOI: 10.1136/vr.101454] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The Heads of Medicines Agencies and the Federation of Veterinarians of Europe undertook a survey to gain a better insight into the decision-making process of veterinarians in Europe when deciding which antibiotics to prescribe. The survey was completed by 3004 practitioners from 25 European countries. Analysis was to the level of different types of practitioner (food producing (FP) animals, companion animals, equines) and country for Belgium, Czech Republic, France, Germany, Spain, Sweden and the UK. Responses indicate no single information source is universally considered critical, though training, published literature and experience were the most important. Factors recorded which most strongly influenced prescribing behaviour were sensitivity tests, own experience, the risk for antibiotic resistance developing and ease of administration. Most practitioners usually take into account responsible use warnings. Antibiotic sensitivity testing is usually performed where a treatment failure has occurred. Significant differences were observed in the frequency of sensitivity testing at the level of types of practitioners and country. The responses indicate a need to improve sensitivity tests and services, with the availability of rapid and cheaper testing being key factors.
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Affiliation(s)
- N De Briyne
- Federation of Veterinarians of Europe, Avenue Tervueren 12, Brussels 1040, Belgium
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83
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Antimicrobials, Susceptibility Testing, and Minimum Inhibitory Concentrations (MIC) in Veterinary Infection Treatment. Vet Clin North Am Small Anim Pract 2013; 43:1079-89. [DOI: 10.1016/j.cvsm.2013.04.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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84
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Suojala L, Kaartinen L, Pyörälä S. Treatment for bovine Escherichia coli mastitis - an evidence-based approach. J Vet Pharmacol Ther 2013; 36:521-31. [PMID: 23679229 DOI: 10.1111/jvp.12057] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
Abstract
Bovine mastitis caused by Escherichia coli can range from being a subclinical infection of the mammary gland to a severe systemic disease. Cow-dependent factors such as lactation stage and age affect the severity of coliform mastitis. Evidence for the efficacy of antimicrobial treatment for E. coli mastitis is very limited. Antimicrobial resistance is generally not a limiting factor for treatment, but it should be monitored to detect changes in resistance profiles. The only antimicrobials for which there is some scientific evidence of beneficial effects in the treatment for E. coli mastitis are fluoroquinolones and cephalosporins. Both are critically important drugs, the use of which in animals destined for food should be limited to specific indications and should be based on bacteriological diagnosis. The suggested routine protocol in dairy herds could target the primary antimicrobial treatment for mastitis, specifically infections caused by gram-positive bacteria. In E. coli mastitis with mild to moderate clinical signs, a non-antimicrobial approach (anti-inflammatory treatment, frequent milking and fluid therapy) should be the first option. In cases of severe E. coli mastitis, parenteral administration of fluoroquinolones, or third- or fourth-generation cephalosporins, is recommended due to the risk of unlimited growth of bacteria in the mammary gland and ensuing bacteremia. Evidence for the efficacy of intramammary-administered antimicrobial treatment for E. coli mastitis is so limited that it cannot be recommended. Nonsteroidal anti-inflammatory drugs have documented the efficacy in the treatment for E. coli mastitis and are recommended for supportive treatment for clinical mastitis.
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Affiliation(s)
- L Suojala
- Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Saarentaus, Finland
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85
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Szweda P, Schielmann M, Kotlowski R, Gorczyca G, Zalewska M, Milewski S. Peptidoglycan hydrolases-potential weapons against Staphylococcus aureus. Appl Microbiol Biotechnol 2012; 96:1157-74. [PMID: 23076591 PMCID: PMC3492699 DOI: 10.1007/s00253-012-4484-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 09/29/2012] [Accepted: 10/01/2012] [Indexed: 11/27/2022]
Abstract
Bacteria of the genus Staphylococcus are common pathogens responsible for a broad spectrum of human and animal infections and belong to the most important etiological factors causing food poisoning. Because of rapid increase in the prevalence of isolation of staphylococci resistant to many antibiotics, there is an urgent need for the development of new alternative chemotherapeutics. A number of studies have recently demonstrated the strong potential of peptidoglycan hydrolases (PHs) to control and treat infections caused by this group of bacteria. PHs cause rapid lysis and death of bacterial cells. The review concentrates on enzymes hydrolyzing peptidoglycan of staphylococci. Usually, they are characterized by high specificity to only Staphylococcus aureus cell wall components; however, some of them are also able to lyse cells of other staphylococci, e.g., Staphylococcus epidermidis-human pathogen of growing importance and also other groups of bacteria. Some PHs strengthen the bactericidal or bacteriostatic activity of common antibiotics, and as a result, they should be considered as component of combined therapy which could definitely reduced the development of bacterial resistance to both enzymes and antibiotics. The preliminary research revealed that most of these enzymes can be produced using heterologous, especially Escherichia coli expression systems; however, still much effort is required to develop more efficient and large-scale production technologies. This review discusses current state on knowledge with emphasis on the possibilities of application of PHs in the context of therapeutics for infections caused by staphylococci.
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Affiliation(s)
- Piotr Szweda
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdańsk University of Technology, ul. G. Narutowicza 11/12, 80-233, Gdańsk, Poland.
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86
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Oral doxycycline for non-systemic urinary tract infections (UTIs) due to P. aeruginosa and other Gram negative uropathogens. Eur J Clin Microbiol Infect Dis 2012; 31:2865-8. [DOI: 10.1007/s10096-012-1680-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Accepted: 06/11/2012] [Indexed: 11/25/2022]
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87
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Cunha BA. Predicting in vivo effectiveness from in vitro susceptibility: A step closer to performing testing of uropathogens in human urine. ACTA ACUST UNITED AC 2012; 44:714-5. [DOI: 10.3109/00365548.2012.673731] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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