1
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Greenwald MA, Meinig SL, Plott LM, Roca C, Higgs MG, Vitko NP, Markovetz MR, Rouillard KR, Carpenter J, Kesimer M, Hill DB, Schisler JC, Wolfgang MC. Mucus polymer concentration and in vivo adaptation converge to define the antibiotic response of Pseudomonas aeruginosa during chronic lung infection. mBio 2024; 15:e0345123. [PMID: 38651896 PMCID: PMC11237767 DOI: 10.1128/mbio.03451-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
The airway milieu of individuals with muco-obstructive airway diseases (MADs) is defined by the accumulation of dehydrated mucus due to hyperabsorption of airway surface liquid and defective mucociliary clearance. Pathological mucus becomes progressively more viscous with age and disease severity due to the concentration and overproduction of mucin and accumulation of host-derived extracellular DNA (eDNA). Respiratory mucus of MADs provides a niche for recurrent and persistent colonization by respiratory pathogens, including Pseudomonas aeruginosa, which is responsible for the majority of morbidity and mortality in MADs. Despite high concentration inhaled antibiotic therapies and the absence of antibiotic resistance, antipseudomonal treatment failure in MADs remains a significant clinical challenge. Understanding the drivers of antibiotic tolerance is essential for developing more effective treatments that eradicate persistent infections. The complex and dynamic environment of diseased airways makes it difficult to model antibiotic efficacy in vitro. We aimed to understand how mucin and eDNA concentrations, the two dominant polymers in respiratory mucus, alter the antibiotic tolerance of P. aeruginosa. Our results demonstrate that polymer concentration and molecular weight affect P. aeruginosa survival post antibiotic challenge. Polymer-driven antibiotic tolerance was not explicitly associated with reduced antibiotic diffusion. Lastly, we established a robust and standardized in vitro model for recapitulating the ex vivo antibiotic tolerance of P. aeruginosa observed in expectorated sputum across age, underlying MAD etiology, and disease severity, which revealed the inherent variability in intrinsic antibiotic tolerance of host-evolved P. aeruginosa populations. IMPORTANCE Antibiotic treatment failure in Pseudomonas aeruginosa chronic lung infections is associated with increased morbidity and mortality, illustrating the clinical challenge of bacterial infection control. Understanding the underlying infection environment, as well as the host and bacterial factors driving antibiotic tolerance and the ability to accurately recapitulate these factors in vitro, is crucial for improving antibiotic treatment outcomes. Here, we demonstrate that increasing concentration and molecular weight of mucin and host eDNA drive increased antibiotic tolerance to tobramycin. Through systematic testing and modeling, we identified a biologically relevant in vitro condition that recapitulates antibiotic tolerance observed in ex vivo treated sputum. Ultimately, this study revealed a dominant effect of in vivo evolved bacterial populations in defining inter-subject ex vivo antibiotic tolerance and establishes a robust and translatable in vitro model for therapeutic development.
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Affiliation(s)
- Matthew A Greenwald
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Suzanne L Meinig
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lucas M Plott
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Cristian Roca
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew G Higgs
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Nicholas P Vitko
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew R Markovetz
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Kaitlyn R Rouillard
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jerome Carpenter
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Mehmet Kesimer
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - David B Hill
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
- Joint Department of Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Jonathan C Schisler
- Department of Pharmacology, The University of North Carolina, Chapel Hill, North Carolina, USA
- McAllister Heart Institute, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Matthew C Wolfgang
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
- Marsico Lung Institute, University of North Carolina, Chapel Hill, North Carolina, USA
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Lyons N, Wu W, Jin Y, Lamont IL, Pletzer D. Using host-mimicking conditions and a murine cutaneous abscess model to identify synergistic antibiotic combinations effective against Pseudomonas aeruginosa. Front Cell Infect Microbiol 2024; 14:1352339. [PMID: 38808066 PMCID: PMC11130353 DOI: 10.3389/fcimb.2024.1352339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/25/2024] [Indexed: 05/30/2024] Open
Abstract
Antibiotic drug combination therapy is critical for the successful treatment of infections caused by multidrug resistant pathogens. We investigated the efficacy of β-lactam and β-lactam/β-lactamase inhibitor combinations with other antibiotics, against the hypervirulent, ceftazidime/avibactam resistant Pseudomonas aeruginosa Liverpool epidemic strain (LES) B58. Although minimum inhibitory concentrations in vitro differed by up to eighty-fold between standard and host-mimicking media, combinatorial effects only marginally changed between conditions for some combinations. Effective combinations in vitro were further tested in a chronic, high-density murine infection model. Colistin and azithromycin demonstrated combinatorial effects with ceftazidime and ceftazidime/avibactam both in vitro and in vivo. Conversely, while tobramycin and tigecycline exhibited strong synergy in vitro, this effect was not observed in vivo. Our approach of using host-mimicking conditions and a sophisticated animal model to evaluate drug synergy against bacterial pathogens represents a promising approach. This methodology may offer insights into the prediction of combination therapy outcomes and the identification of potential treatment failures.
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Affiliation(s)
- Nikita Lyons
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Weihui Wu
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Iain L. Lamont
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Daniel Pletzer
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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3
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Cogen JD, Quon BS. Update on the diagnosis and management of cystic fibrosis pulmonary exacerbations. J Cyst Fibros 2024:S1569-1993(24)00047-X. [PMID: 38677887 DOI: 10.1016/j.jcf.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/28/2024] [Accepted: 04/05/2024] [Indexed: 04/29/2024]
Abstract
Pulmonary exacerbations in people with cystic fibrosis are associated with significant morbidity and reduced quality of life. Pulmonary exacerbation treatment guidelines, published by an expert panel assembled by the Cystic Fibrosis Foundation nearly 15 years ago, were primarily consensus-based as there were several gaps in the evidence base. In particular, limited evidence existed regarding optimal pulmonary exacerbation treatment strategies, including duration of antibiotic therapy, treatment location, antibiotic selection, and the role of systemic corticosteroids. Over the last decade, results from observational studies and large multi-center randomized controlled trials have begun to answer important questions related to pulmonary exacerbation treatment. This review focuses on the diagnosis, etiology, and changing epidemiology of pulmonary exacerbations, and also summarizes the most recent and up-to-date studies describing pulmonary exacerbation treatment. Finally, this review provides consideration for future pulmonary exacerbation research priorities, particularly in the current highly effective modulator therapy era.
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Affiliation(s)
- Jonathan D Cogen
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington, USA.
| | - Bradley S Quon
- Division of Respiratory Medicine, Department of Medicine, St. Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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Rice J, Gibson J, Young E, Souder K, Cunningham K, Schmitt DM. Low Oxygen Concentration Reduces Neisseria gonorrhoeae Susceptibility to Resazurin. Antibiotics (Basel) 2024; 13:395. [PMID: 38786124 PMCID: PMC11117329 DOI: 10.3390/antibiotics13050395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/18/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Neisseria gonorrhoeae has developed resistance to every antibiotic currently approved for the treatment of gonorrhea, prompting the development of new therapies. The phenoxazine dye resazurin exhibits robust antimicrobial activity against N. gonorrhoeae in vitro but fails to limit vaginal colonization by N. gonorrhoeae in a mouse model. The lack of in vivo efficacy may be due to oxygen limitation as in vitro susceptibility assays with resazurin are conducted under atmospheric oxygen while a microaerophilic environment is present in the vagina. Here, we utilized broth microdilution assays to determine the susceptibility of N. gonorrhoeae to resazurin under low and atmospheric oxygen conditions. The minimal inhibitory concentration of resazurin for multiple N. gonorrhoeae clinical isolates was significantly higher under low oxygen. This effect was specific to resazurin as N. gonorrhoeae was equally susceptible to other antibiotics under low and atmospheric oxygen conditions. The reduced susceptibility of N. gonorrhoeae to resazurin under low oxygen was largely attributed to reduced oxidative stress, as the addition of antioxidants under atmospheric oxygen mimicked the reduced susceptibility to resazurin observed under low oxygen. Together, these data suggest oxygen concentration is an important factor to consider when evaluating the efficacy of new antibiotics against N. gonorrhoeae in vitro.
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Affiliation(s)
| | | | | | | | | | - Deanna M. Schmitt
- Department of Biomedical Sciences, West Liberty University, West Liberty, WV 26074, USA
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Howard A, Aston S, Gerada A, Reza N, Bincalar J, Mwandumba H, Butterworth T, Hope W, Buchan I. Antimicrobial learning systems: an implementation blueprint for artificial intelligence to tackle antimicrobial resistance. Lancet Digit Health 2024; 6:e79-e86. [PMID: 38123255 DOI: 10.1016/s2589-7500(23)00221-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/17/2023] [Accepted: 10/21/2023] [Indexed: 12/23/2023]
Abstract
The proliferation of various forms of artificial intelligence (AI) brings many opportunities to improve health care. AI models can harness complex evolving data, inform and augment human actions, and learn from health outcomes such as morbidity and mortality. The global public health challenge of antimicrobial resistance (AMR) needs large-scale optimisation of antimicrobial use and wider infection care, which could be enabled by carefully constructed AI models. As AI models become increasingly useful and robust, health-care systems remain challenging places for their deployment. An implementation gap exists between the promise of AI models and their use in patient and population care. Here, we outline an adaptive implementation and maintenance framework for AI models to improve antimicrobial use and infection care as a learning system. The roles of AMR problem identification, law and regulation, organisational support, data processing, and AI development, assessment, maintenance, and scalability in the implementation of AMR-targeted AI models are considered.
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Affiliation(s)
- Alex Howard
- Department of Antimicrobial Pharmacodynamics and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK.
| | - Stephen Aston
- Department of Antimicrobial Pharmacodynamics and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Alessandro Gerada
- Department of Antimicrobial Pharmacodynamics and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Nada Reza
- Department of Antimicrobial Pharmacodynamics and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Jason Bincalar
- Department of Health Data Science, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Henry Mwandumba
- Malawi Liverpool Wellcome Programme, Kamuzu University of Health Sciences, Blantyre, Malawi; Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Tom Butterworth
- Combined Intelligence for Public Health Action, NHS Cheshire and Merseyside, Warrington, UK
| | - William Hope
- Department of Antimicrobial Pharmacodynamics and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; Liverpool University Hospitals NHS Foundation Trust, Liverpool, UK
| | - Iain Buchan
- Department of Public Health, Policy and Systems, Institute of Population Health, University of Liverpool, Liverpool, UK; Combined Intelligence for Public Health Action, NHS Cheshire and Merseyside, Warrington, UK
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Greenwald MA, Meinig SL, Plott LM, Roca C, Higgs MG, Vitko NP, Markovetz MR, Rouillard KR, Carpenter J, Kesimer M, Hill DB, Schisler JC, Wolfgang MC. Mucus polymer concentration and in vivo adaptation converge to define the antibiotic response of Pseudomonas aeruginosa during chronic lung infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572620. [PMID: 38187602 PMCID: PMC10769284 DOI: 10.1101/2023.12.20.572620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The airway milieu of individuals with muco-obstructive airway diseases (MADs) is defined by the accumulation of dehydrated mucus due to hyperabsorption of airway surface liquid and defective mucociliary clearance. Pathological mucus becomes progressively more viscous with age and disease severity due to the concentration and overproduction of mucin and accumulation of host-derived extracellular DNA (eDNA). Respiratory mucus of MADs provides a niche for recurrent and persistent colonization by respiratory pathogens, including Pseudomonas aeruginosa , which is responsible for the majority of morbidity and mortality in MADs. Despite high concentration inhaled antibiotic therapies and the absence of antibiotic resistance, antipseudomonal treatment failure in MADs remains a significant clinical challenge. Understanding the drivers of antibiotic recalcitrance is essential for developing more effective treatments that eradicate persistent infections. The complex and dynamic environment of diseased airways makes it difficult to model antibiotic efficacy in vitro . We aimed to understand how mucin and eDNA concentrations, the two dominant polymers in respiratory mucus, alter the antibiotic tolerance of P. aeruginosa . Our results demonstrate that polymer concentration and molecular weight affect P. aeruginosa survival post antibiotic challenge. Polymer-driven antibiotic tolerance was not explicitly associated with reduced antibiotic diffusion. Lastly, we established a robust and standardized in vitro model for recapitulating the ex vivo antibiotic tolerance of P. aeruginosa observed in expectorated sputum across age, underlying MAD etiology, and disease severity, which revealed the inherent variability in intrinsic antibiotic tolerance of host-evolved P. aeruginosa populations. Importance Antibiotic treatment failure in Pseudomonas aeruginosa chronic lung infections is associated with increased morbidity and mortality, illustrating the clinical challenge of bacterial infection control. Understanding the underlying infection environment, as well as the host and bacterial factors driving antibiotic tolerance and the ability to accurately recapitulate these factors in vitro , is crucial for improving antibiotic treatment outcomes. Here, we demonstrate that increasing concentration and molecular weight of mucin and host eDNA drive increased antibiotic tolerance to tobramycin. Through systematic testing and modeling, we identified a biologically relevant in vitro condition that recapitulates antibiotic tolerance observed in ex vivo treated sputum. Ultimately, this study revealed a dominant effect of in vivo evolved bacterial populations in defining inter-subject ex vivo antibiotic tolerance and establishes a robust and translatable in vitro model for therapeutic development.
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7
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Maranchick NF, Webber J, Alshaer MH, Felton TW, Peloquin CA. Impact of Beta-Lactam Target Attainment on Resistance Development in Patients with Gram-Negative Infections. Antibiotics (Basel) 2023; 12:1696. [PMID: 38136730 PMCID: PMC10740680 DOI: 10.3390/antibiotics12121696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND The objective was to identify associations between beta-lactam pharmacokinetic/pharmacodynamic (PK/PD) targets and Gram-negative bacteria resistance emergence in patients. METHODS Retrospective data were collected between 2016 to 2019 at the University of Florida Health-Shands Hospital in Gainesville, FL. Adult patients with two Gram-negative isolates receiving cefepime, meropenem, or piperacillin-tazobactam and who had plasma beta-lactam concentrations were included. Beta-lactam exposures and time free drug concentrations that exceeded minimum inhibitory concentrations (ƒT > MIC), four multiples of MIC (ƒT > 4× MIC), and free area under the time concentration curve to MIC (ƒAUC/MIC) were generated. Resistance emergence was defined as any increase in MIC or two-fold increase in MIC. Multiple regression analysis assessed the PK/PD parameter impact on resistance emergence. RESULTS Two hundred fifty-six patients with 628 isolates were included. The median age was 58 years, and 59% were males. Cefepime was the most common beta-lactam (65%) and Pseudomonas aeruginosa the most common isolate (43%). The mean daily ƒAUC/MIC ≥ 494 was associated with any increase in MIC (p = 0.002) and two-fold increase in MIC (p = 0.004). The daily ƒAUC/MIC ≥ 494 was associated with decreased time on antibiotics (p = 0.008). P. aeruginosa was associated with any increase in MIC (OR: 6.41, 95% CI [3.34-12.28]) or 2× increase in MIC (7.08, 95% CI [3.56-14.07]). CONCLUSIONS ƒAUC/MIC ≥ 494 may be associated with decreased Gram-negative resistance emergence.
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Affiliation(s)
- Nicole F. Maranchick
- Infectious Disease Pharmacokinetics Lab, Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
| | - Jessica Webber
- College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Mohammad H. Alshaer
- Infectious Disease Pharmacokinetics Lab, Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
| | - Timothy W. Felton
- North West Ventilation Unit, Manchester University NHS Foundation Trust, Manchester M23 9LT, UK
- Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester M13 9NT, UK
| | - Charles A. Peloquin
- Infectious Disease Pharmacokinetics Lab, Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
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Olivença DV, Davis JD, Kumbale CM, Zhao CY, Brown SP, McCarty NA, Voit EO. Mathematical models of cystic fibrosis as a systemic disease. WIREs Mech Dis 2023; 15:e1625. [PMID: 37544654 PMCID: PMC10843793 DOI: 10.1002/wsbm.1625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 06/22/2023] [Accepted: 07/06/2023] [Indexed: 08/08/2023]
Abstract
Cystic fibrosis (CF) is widely known as a disease of the lung, even though it is in truth a systemic disease, whose symptoms typically manifest in gastrointestinal dysfunction first. CF ultimately impairs not only the pancreas and intestine but also the lungs, gonads, liver, kidneys, bones, and the cardiovascular system. It is caused by one of several mutations in the gene of the epithelial ion channel protein CFTR. Intense research and improved antimicrobial treatments during the past eight decades have steadily increased the predicted life expectancy of a person with CF (pwCF) from a few weeks to over 50 years. Moreover, several drugs ameliorating the sequelae of the disease have become available in recent years, and notable treatments of the root cause of the disease have recently generated substantial improvements in health for some but not all pwCF. Yet, numerous fundamental questions remain unanswered. Complicating CF, for instance in the lung, is the fact that the associated insufficient chloride secretion typically perturbs the electrochemical balance across epithelia and, in the airways, leads to the accumulation of thick, viscous mucus and mucus plaques that cannot be cleared effectively and provide a rich breeding ground for a spectrum of bacterial and fungal communities. The subsequent infections often become chronic and respond poorly to antibiotic treatments, with outcomes sometimes only weakly correlated with the drug susceptibility of the target pathogen. Furthermore, in contrast to rapidly resolved acute infections with a single target pathogen, chronic infections commonly involve multi-species bacterial communities, called "infection microbiomes," that develop their own ecological and evolutionary dynamics. It is presently impossible to devise mathematical models of CF in its entirety, but it is feasible to design models for many of the distinct drivers of the disease. Building upon these growing yet isolated modeling efforts, we discuss in the following the feasibility of a multi-scale modeling framework, known as template-and-anchor modeling, that allows the gradual integration of refined sub-models with different granularity. The article first reviews the most important biomedical aspects of CF and subsequently describes mathematical modeling approaches that already exist or have the potential to deepen our understanding of the multitude aspects of the disease and their interrelationships. The conceptual ideas behind the approaches proposed here do not only pertain to CF but are translatable to other systemic diseases. This article is categorized under: Congenital Diseases > Computational Models.
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Affiliation(s)
- Daniel V. Olivença
- Center for Engineering Innovation, The University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, USA
| | - Jacob D. Davis
- Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, Georgia
| | - Carla M. Kumbale
- Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, Georgia
| | - Conan Y. Zhao
- Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Samuel P. Brown
- Department of Biological Sciences, Georgia Tech and Emory University, Atlanta, Georgia
| | - Nael A. McCarty
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Eberhard O. Voit
- Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, Georgia
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Humphries RM, Miller L, Zimmer B, Matuschek E, Hindler JA. Contemporary Considerations for Establishing Reference Methods for Antibacterial Susceptibility Testing. J Clin Microbiol 2023; 61:e0188622. [PMID: 36971571 PMCID: PMC10281161 DOI: 10.1128/jcm.01886-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Antibacterial susceptibility testing (AST) is performed to guide therapy, perform resistance surveillance studies, and support development of new antibacterial agents. For 5 decades, broth microdilution (BMD) has served as the reference method to assess in vitro activity of antibacterial agents against which both novel agents and diagnostic tests have been measured. BMD relies on in vitro inhibition or killing of bacteria. It is associated with several limitations: it is a poor mimic of the in vivo milieu of bacterial infections, requires multiple days to perform, and is associated with subtle, difficult to control variability. In addition, new reference methods will soon be needed for novel agents whose activity cannot be evaluated by BMD (e.g., those that target virulence). Any new reference methods must be standardized, correlated with clinical efficacy and be recognized internationally by researchers, industry, and regulators. Herein, we describe current reference methods for in vitro assessment of antibacterial activity and highlight key considerations for the generation of novel reference methods.
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Affiliation(s)
- Romney M. Humphries
- Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Linda Miller
- CMID Pharma Consulting, LLC, Dresher, Pennsylvania, USA
| | - Barbara Zimmer
- Beckman Coulter Microbiology, Sacramento, California, USA
| | | | - Janet A. Hindler
- Los Angeles County Department of Public Health, Public Health Laboratory, Los Angeles, California, USA
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10
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Kristensen M, de Koff EM, Chu ML, Groendijk S, Tramper-Stranders GA, de Winter-de Groot KM, Janssens HM, Tiddens HA, van Westreenen M, Sanders EAM, Arets BHGM, van der Ent CK, Prevaes SMPJ, Bogaert D. 16S rRNA-Based Microbiota Profiling Assists Conventional Culture Analysis of Airway Samples from Pediatric Cystic Fibrosis Patients. Microbiol Spectr 2023; 11:e0405722. [PMID: 37199622 PMCID: PMC10269535 DOI: 10.1128/spectrum.04057-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 04/21/2023] [Indexed: 05/19/2023] Open
Abstract
16S-based sequencing provides broader information on the respiratory microbial community than conventional culturing. However, it (often) lacks species- and strain-level information. To overcome this issue, we used 16S rRNA-based sequencing results from 246 nasopharyngeal samples obtained from 20 infants with cystic fibrosis (CF) and 43 healthy infants, which were all 0 to 6 months old, and compared them to both standard (blind) diagnostic culturing and a 16S-sequencing-informed "targeted" reculturing approach. Using routine culturing, we almost uniquely detected Moraxella catarrhalis, Staphylococcus aureus, and Haemophilus influenzae (42%, 38%, and 33% of samples, respectively). Using the targeted reculturing approach, we were able to reculture 47% of the top-5 operational taxonomical units (OTUs) in the sequencing profiles. In total, we identified 60 species from 30 genera with a median of 3 species per sample (range, 1 to 8). We also identified up to 10 species per identified genus. The success of reculturing the top-5 genera present from the sequencing profile depended on the genus. In the case of Corynebacterium being in the top 5, we recultured them in 79% of samples, whereas for Staphylococcus, this value was only 25%. The success of reculturing was also correlated with the relative abundance of those genera in the corresponding sequencing profile. In conclusion, revisiting samples using 16S-based sequencing profiles to guide a targeted culturing approach led to the detection of more potential pathogens per sample than conventional culturing and may therefore be useful in the identification and, consequently, treatment of bacteria considered relevant for the deterioration or exacerbation of disease in patients like those with CF. IMPORTANCE Early and effective treatment of pulmonary infections in cystic fibrosis is vital to prevent chronic lung damage. Although microbial diagnostics and treatment decisions are still based on conventional culture methods, research is gradually focusing more on microbiome and metagenomic-based approaches. This study compared the results of both methods and proposed a way to combine the best of both worlds. Many species can relatively easily be recultured based on the 16S-based sequencing profile, and it provides more in-depth information about the microbial composition of a sample than that obtained through routine (blind) diagnostic culturing. Still, well-known pathogens can be missed by both routine diagnostic culture methods as well as by targeted reculture methods, sometimes even when they are highly abundant, which may be a consequence of either sample storage conditions or antibiotic treatment at the time of sampling.
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Affiliation(s)
- Maartje Kristensen
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emma M. de Koff
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
- Spaarne Gasthuis Academy, Spaarne Gasthuis, Hoofddorp, The Netherlands
| | - Mei Ling Chu
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Simone Groendijk
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Karin M. de Winter-de Groot
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hettie M. Janssens
- Department of Pediatric Pulmonology and Allergology, Sophia Children’s Hospital, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Harm A. Tiddens
- Department of Pediatric Pulmonology and Allergology, Sophia Children’s Hospital, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Mireille van Westreenen
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Elisabeth A. M. Sanders
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
- National Institute for Public Health and the Environment, Centre for Infectious Disease Control, Bilthoven, The Netherlands
| | - Bert H. G. M. Arets
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Cornelis K. van der Ent
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Sabine M. P. J. Prevaes
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Debby Bogaert
- Department of Pediatrics, Wilhelmina Children’s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
- The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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Amábile-Cuevas CF. Ascorbate and Antibiotics, at Concentrations Attainable in Urine, Can Inhibit the Growth of Resistant Strains of Escherichia coli Cultured in Synthetic Human Urine. Antibiotics (Basel) 2023; 12:985. [PMID: 37370304 DOI: 10.3390/antibiotics12060985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
There are conflicting reports on the antibacterial activity of ascorbate; all at concentrations much higher than the typical in human plasma, but that can be reached in urine. The effect of 10 mM ascorbate (in itself not inhibitory) along with antibiotics, was tested both in Mueller-Hinton broth (MHb) and in synthetic human urine (SHU), against resistant isolates of Escherichia coli from lower urinary infections. The activity of nitrofurantoin and sulfamethoxazole was higher in SHU than in MHb; minimal inhibitory concentrations (MICs) in SHU with ascorbate were below typical urinary concentrations. For other antibiotics, MICs were the same in MHb vs. SHU, with no effect of ascorbate in MHb; but in SHU with ascorbate, MICs of ciprofloxacin and gentamicin also went below reported urinary concentrations, with a lesser effect with norfloxacin and trimethoprim, and none with ampicillin. The effect of ascorbate was independent of oxygen and not related to the susceptibility of each strain to oxidative stress. Ascorbate oxidizes during incubation in SHU, and bacterial growth partially prevented oxidation. These results suggest that 10 mM ascorbate can enhance the inhibitory activity of antibiotics upon resistant strains in urine. Clinical experimentation with ascorbate-antibiotic combinations against urinary infections caused by resistant bacteria is warranted.
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12
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Chen L, Qu X, Su J, Yao H, Yuan Q, Wang Y, Li N, Wu G, Liu X, Hu J, Zhang J. The dilemma of antibiotic susceptibility and clinical decision-making in a multi-drug-resistant Pseudomonas aeruginosa bloodstream infection. Front Pharmacol 2023; 14:1183332. [PMID: 37324460 PMCID: PMC10266203 DOI: 10.3389/fphar.2023.1183332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/15/2023] [Indexed: 06/17/2023] Open
Abstract
Objective: How to choose the appropriate antibiotics and dosage has always been a difficult issue during the treatment of multi-drug-resistant bacterial infections. Our study aims to resolve this difficulty by introducing our multi-disciplinary treatment (MDT) clinical decision-making scheme based on rigorous interpretation of antibiotic susceptibility tests and precise therapeutic drug monitoring (TDM)-guided dosage adjustment. Method: The treatment course of an elderly patient who developed a multi-drug-resistant Pseudomonas aeruginosa (MDRPA) bloodstream infection from a brain abscess was presented. Results: In the treatment process, ceftazidime-avibactam (CAZ-AVI) was used empirically for treating the infection and clinical symptoms improved. However, the follow-up bacterial susceptibility test showed that the bacteria were resistant to CAZ-AVI. Considering the low fault tolerance of clinical therapy, the treatment was switched to a 1 mg/kg maintenance dose of susceptible polymyxin B, and TDM showed that the AUC24h, ss of 65.5 mgh/L had been achieved. However, clinical symptoms were not improved after 6 days of treatment. Facing the complicated situation, the cooperation of physicians, clinical pharmacologists, and microbiologists was applied, and the treatment finally succeeded with the pathogen eradicated when polymyxin B dose was increased to 1.4 mg/kg, with the AUC24h, ss of 98.6 mgh/L. Conclusion: MDT collaboration on the premise of scientific and standardized drug management is helpful for the recovery process in patients. The empirical judgment of doctors, the medication recommendations from experts in the field of TDM and pharmacokinetics/pharmacodynamics, and the drug susceptibility results provided by the clinical microbiology laboratory all provide the direction of treatment.
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Affiliation(s)
- Long Chen
- Department of Neurosurgery and Neurocritical Care, Huashan Hospital, Fudan University, Shanghai, China
| | - Xingyi Qu
- Fudan University and Key Laboratory of Clinical Pharmacology of Antibiotics and National Health Commission and National Clinical Research Center for Aging and Medicine, Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai, China
| | - Jingqian Su
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, College of Life Science, Fujian Normal University, Fuzhou, China
| | - Haijun Yao
- Department of Neurosurgery and Neurocritical Care, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiang Yuan
- Department of Neurosurgery and Neurocritical Care, Huashan Hospital, Fudan University, Shanghai, China
| | - Yu Wang
- Fudan University and Key Laboratory of Clinical Pharmacology of Antibiotics and National Health Commission and National Clinical Research Center for Aging and Medicine, Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Nanyang Li
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai, China
| | - Gang Wu
- Department of Neurosurgery and Neurocritical Care, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaofen Liu
- Fudan University and Key Laboratory of Clinical Pharmacology of Antibiotics and National Health Commission and National Clinical Research Center for Aging and Medicine, Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Jin Hu
- Department of Neurosurgery and Neurocritical Care, Huashan Hospital, Fudan University, Shanghai, China
| | - Jing Zhang
- Fudan University and Key Laboratory of Clinical Pharmacology of Antibiotics and National Health Commission and National Clinical Research Center for Aging and Medicine, Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
- Phase I Unit, Huashan Hospital, Fudan University, Shanghai, China
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13
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Kowalska-Krochmal B, Mączyńska B, Smutnicka D, Secewicz A, Krochmal G, Laufer K, Dudek-Wicher R. Reliability of E-Tests and the Phoenix Automated Method in Assessing Susceptibility to IV Fosfomycin-Comparative Studies Relative to the Reference Method. Pathogens 2023; 12:pathogens12050700. [PMID: 37242370 DOI: 10.3390/pathogens12050700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
The agar dilution method (ADM) recommended for IV fosfomycin (IV FOS) is complex and labor-intensive. Keeping in mind the reality of everyday laboratory work, we have evaluated the agreement of IV FOS susceptibility results obtained using the E-test and the Phoenix system with the results obtained using the ADM. MATERIALS AND METHODS The tests were performed on 860 strains. To evaluate susceptibility to IV FOS, BioMerieux E-tests (bioMerieux, Warsaw, Poland), BD Phoenix panels (BD Phoenix, Sparks, MD, USA), and the ADM were used. Clinical interpretation was performed in accordance with EUCAST Guidance (v12.0, 2021). The significance of the E-test and the Phoenix was analyzed in relation to the ADM by defining categorical agreement (CA), major error (ME), and very major error (VME). Essential agreement (EA) has also been defined for the E-test. A method was considered reliable, in accordance with ISO 20776-2:2007, when CA and EA were above 89.9% and VME was <3%. RESULTS A categorical agreement of >98.9% was demonstrated between the E-test and the ADM for overall strains and for Echerichia coli, ESBL-producing Enterobacterales, and Staphylococcus aureus, while between the Phoenix and the ADM, a CA of >98.9% was shown only for Escherichia coli, Staphylococcus aureus, and Proteus spp. A very major error rate of <3% was obtained only for Staphylococcus aureus and MBL-producing Pseudomonas evaluated by both the E-test and the Phoenix. An essential agreement of >98.9% between the E-test and the ADM has not been demonstrated for any of the tested groups of strains. The Phoenix yielded more VMEs than the E-test (50 and 46, respectively). The highest VME rate was demonstrated using the Phoenix method for Enterobacter spp. (53.83%). CONCLUSIONS Both the E-test and the Phoenix have turned out to be reliable in assessing IV FOS susceptibility only for Staphylococcus aureus (CA > 89.9% and VME < 3%). For the remaining tested groups of strains and genera, the simultaneous high CA rate and low VME rate required by ISO were not achieved. Both methods fared particularly badly in detecting strains resistant to IV.
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Affiliation(s)
- Beata Kowalska-Krochmal
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
| | - Beata Mączyńska
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
| | - Danuta Smutnicka
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
| | - Anna Secewicz
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
| | - Grzegorz Krochmal
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
| | - Klaudyna Laufer
- Laboratory Diagnostics Department, Jan Mikulicz-Radecki University Teaching Hospital, 50-556 Wroclaw, Poland
| | - Ruth Dudek-Wicher
- Department of Pharmaceutical Microbiology and Parasitology, Faculty of Pharmacy, Medical University of Silesian Piasts in Wroclaw, 50-556 Wroclaw, Poland
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Druseikis M, Mottola A, Berman J. The Metabolism of Susceptibility: Clearing the FoG Between Tolerance and Resistance in Candida albicans. CURRENT CLINICAL MICROBIOLOGY REPORTS 2023; 10:36-46. [DOI: 10.1007/s40588-023-00189-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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15
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Asempa TE, Kois AK, Gill CM, Nicolau DP. Phenotypes, genotypes and breakpoints: an assessment of β-lactam/β-lactamase inhibitor combinations against OXA-48. J Antimicrob Chemother 2023; 78:636-645. [PMID: 36626311 DOI: 10.1093/jac/dkac425] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 09/21/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Two of the three recently approved β-lactam agent (BL)/β-lactamase inhibitor (BLI) combinations have higher CLSI susceptibility breakpoints (ceftazidime/avibactam 8 mg/L; meropenem/vaborbactam 4 mg/L) compared with the BL alone (ceftazidime 4 mg/L; meropenem 1 mg/L). This can lead to a therapeutic grey area on susceptibility reports depending on resistance mechanism. For instance, a meropenem-resistant OXA-48 isolate (MIC 4 mg/L) may appear as meropenem/vaborbactam-susceptible (MIC 4 mg/L) despite vaborbactam's lack of OXA-48 inhibitory activity. METHODS OXA-48-positive (n = 51) and OXA-48-negative (KPC, n = 5; Klebsiella pneumoniae wild-type, n = 1) Enterobacterales were utilized. Susceptibility tests (broth microdilution) were conducted with ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam, as well as their respective BL partner. Antimicrobial activity of all six agents was evaluated in the murine neutropenic thigh model using clinically relevant exposures. Efficacy was assessed as the change in bacterial growth at 24 h, compared with 0 h controls. RESULTS On average, the three BL/BLI agents resulted in robust bacteria killing among OXA-48-negative isolates. Among OXA-48-positive isolates, poor in vivo activity with imipenem/relebactam was concordant with its resistant phenotypic profile. Variable meropenem/vaborbactam activity was observed among isolates with a 'susceptible' MIC of 4 mg/L. Only 30% (7/23) of isolates at meropenem/vaborbactam MICs of 2 and 4 mg/L met the ≥1-log bacterial reduction threshold predictive of clinical efficacy in serious infections. In contrast, ceftazidime/avibactam resulted in marked bacterial density reduction across the range of MICs, and 96% (49/51) of isolates exceeded the ≥1-log bacterial reduction threshold. CONCLUSIONS Data demonstrate that current imipenem/relebactam and ceftazidime/avibactam CLSI breakpoints are appropriate. Data also suggest that higher meropenem/vaborbactam breakpoints relative to meropenem can translate to potentially poor clinical outcomes in patients infected with OXA-48-harbouring isolates.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Abigail K Kois
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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16
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AtbFinder Diagnostic Test System Improves Optimal Selection of Antibiotic Therapy in Persons with Cystic Fibrosis. J Clin Microbiol 2023; 61:e0155822. [PMID: 36602344 PMCID: PMC9879114 DOI: 10.1128/jcm.01558-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cystic fibrosis (CF) is characterized by mutations of CFTR that lead to increased viscous secretions, bacterial colonization, and recurrent infections. Chronic Pseudomonas aeruginosa infection in persons with CF is associated with progressive and accelerated lung function decline despite aggressive antibiotic treatment. We report the management of respiratory infections in persons with CF with antibiotic therapy that was based on the recommendations of AtbFinder, a novel, rapid, culture-based diagnostic test system that employs a novel paradigm of antibiotic selection. AtbFinder mimics bacterial interactions with antibiotics at concentrations that can be achieved in affected tissues or organs and models conditions of interbacterial interactions within polymicrobial biofilms. This open-label, single-arm, investigator-initiated clinical study was designed to identify the efficacy of antibiotics selected using AtbFinder in persons with CF. Microbiological and clinical parameters were assessed following the change of antibiotic therapy to antibiotics selected with AtbFinder between January 2016 and December 2018 and retrospectively compared with clinical data collected between January 2013 and December 2015. We enrolled 35 persons with CF (33 with chronic P. aeruginosa colonization). Antibiotics selected using AtbFinder resulted in clearance of P. aeruginosa in 81.8% of subsequent cultures, decreased pulmonary exacerbations from 1.21 per patient per annum to 0, and an increase in predicted percent predicted forced expiratory volume in 1 s up to 28.4% from baseline. The number of systemic antibiotic courses used in patients after switching to the AtbFinder-selected therapy was reduced from 355 to 178. These findings describe the superiority of antibiotic regimens selected with AtbFinder compared with routine antimicrobial susceptibility testing.
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17
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Overcoming Antibiotic Resistance with Novel Paradigms of Antibiotic Selection. Microorganisms 2022; 10:microorganisms10122383. [PMID: 36557636 PMCID: PMC9781420 DOI: 10.3390/microorganisms10122383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/04/2022] Open
Abstract
Conventional antimicrobial susceptibility tests, including phenotypic and genotypic methods, are insufficiently accurate and frequently fail to identify effective antibiotics. These methods predominantly select therapies based on the antibiotic response of only the lead bacterial pathogen within pure bacterial culture. However, this neglects the fact that, in the majority of human infections, the lead bacterial pathogens are present as a part of multispecies communities that modulate the response of these lead pathogens to antibiotics and that multiple pathogens can contribute to the infection simultaneously. This discrepancy is a major cause of the failure of antimicrobial susceptibility tests to detect antibiotics that are effective in vivo. This review article provides a comprehensive overview of the factors that are missed by conventional antimicrobial susceptibility tests and it explains how accounting for these methods can aid the development of novel diagnostic approaches.
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18
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Asempa TE, Kois AK, Gill CM, Nicolau DP. Phenotypes, genotypes and breakpoints: an assessment of β-lactam/ β-lactamase inhibitor combinations against OXA-48. J Antimicrob Chemother 2022; 77:2622-2631. [PMID: 35325165 DOI: 10.1093/jac/dkac074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/10/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Two out of the three recently approved β-lactam (BL)/β-lactamase inhibitors (BLIs) have higher CLSI susceptibility breakpoints (ceftazidime/avibactam 8 mg/L; meropenem/vaborbactam 4 mg/L) compared with the BL alone (ceftazidime 4 mg/L; meropenem 1 mg/L). This can lead to a therapeutic grey area on susceptibility reports depending on resistance mechanism. For instance, a meropenem-resistant OXA-48 isolate (MIC 4 mg/L) may appear as meropenem/vaborbactam-susceptible (MIC 4 mg/L) despite vaborbactam's lack of OXA-48 inhibitory activity. METHODS OXA-48-positive (n = 51) and OXA-48-negative (KPC, n = 5; Klebsiella pneumoniae WT, n = 1) Enterobacterales were utilized. Susceptibility tests (broth microdilution) were conducted with ceftazidime/avibactam, imipenem/relebactam and meropenem/vaborbactam, as well as their respective BL partner. Antimicrobial activity of all six agents was evaluated in the murine neutropenic thigh model using clinically relevant exposures. Efficacy was assessed as the change in bacterial growth at 24 h, compared with 0 h controls. RESULTS On average, the three BL/BLI agents resulted in robust bacteria killing among OXA-48-negative isolates. Among OXA-48-positive isolates, poor in vivo activity with imipenem/relebactam was concordant with its resistant phenotypic profile. Variable meropenem/vaborbactam activity was observed among isolates with a 'susceptible' MIC of 4 mg/L. Only 30% (7/23) of isolates at meropenem/vaborbactam MICs of 2 and 4 mg/L met the ≥1 log bacterial reduction threshold predictive of clinical efficacy in serious infections. In contrast, ceftazidime/avibactam resulted in marked bacterial density reduction across the range of MICs and 73% (37/51) of isolates exceeded the ≥1 log bacterial reduction threshold. CONCLUSIONS Data demonstrate that current imipenem/relebactam and ceftazidime/avibactam CLSI breakpoints are appropriate. Data also suggest that higher meropenem/vaborbactam breakpoints relative to meropenem can translate to potentially poor clinical outcomes in patients infected with OXA-48-harbouring isolates.
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Affiliation(s)
- Tomefa E Asempa
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Abigail K Kois
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Christian M Gill
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
- Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
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19
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Sebbag L, Broadbent VL, Kenne DE, Perrin AL, Mochel JP. Albumin in Tears Modulates Bacterial Susceptibility to Topical Antibiotics in Ophthalmology. Front Med (Lausanne) 2021; 8:663212. [PMID: 34917625 PMCID: PMC8669104 DOI: 10.3389/fmed.2021.663212] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 11/02/2021] [Indexed: 01/12/2023] Open
Abstract
Bacterial keratitis is a serious and vision-threatening condition in veterinary and human patients, one that often requires culture and susceptibility testing to adjust therapy and improve clinical outcomes. The present study challenges the antimicrobial susceptibility testing (AST) paradigm in ophthalmology, enabling more accurate in vitro-to-in vivo translation by incorporating factors normally present during host-pathogen interactions in clinical patients. Thirty bacteria (10 Staphylococcus pseudintermedius, 10 Streptococcus canis, 10 Pseudomonas aeruginosa) were isolated from canine patients with infectious keratitis. For each isolate, commercial plates (Sensititre™ JOEYE2) were used to assess the minimal inhibitory concentration (MIC) of 17 different antibiotics in the absence (0% albumin, control) or presence of canine albumin (0.01–2%). For Staphylococcus pseudintermedius, the experiment was repeated with actual tear fluid collected from canine eyes with ocular surface inflammation. Kruskal-Wallis, Wilcoxon signed rank test and Spearman's correlation tests were used for statistical analysis. Clinical outcomes were unfavorable in selected canine patients with bacterial keratitis (e.g., globe perforation, graft dehiscence) despite standard AST (i.e., 0% albumin in test medium) confirming that most corneal infections (93%) were susceptible to ≥1 topical antibiotics used at the initial visit. Albumin levels ≥0.05% increased MICs in a dose-dependent, bacteria-specific, and antibiotic-specific manner. No significant differences (P = 1.000) were noted in MICs of any antibiotic whether albumin or tear fluid was added to the Mueller-Hinton broth. Percent protein binding inherent to each antibiotic was associated with clinical interpretations (Spearman's rho = −0.53, P = 0.034) but not changes in MICs. Albumin in tears impacted the efficacy of selected ophthalmic antibiotics as only the unbound portion of an antibiotic is microbiologically active. The present findings could improve decision making of clinicians managing bacterial keratitis, reduce development of antimicrobial resistance, influence current guidelines set by the Clinical and Laboratory Standards Institute, and serve as a reference for bacteriological evaluations across medical fields and across species.
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Affiliation(s)
- Lionel Sebbag
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel.,Department of Biomedical Sciences, SMART Pharmacology, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Victoria L Broadbent
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Danielle E Kenne
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Ashtyn L Perrin
- Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
| | - Jonathan P Mochel
- Department of Biomedical Sciences, SMART Pharmacology, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
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20
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Evaluation of clinicians' knowledge and use of minimum inhibitory concentration values. Braz J Infect Dis 2021; 25:101656. [PMID: 34843708 PMCID: PMC9067004 DOI: 10.1016/j.bjid.2021.101656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/06/2021] [Indexed: 11/21/2022] Open
Abstract
Routinely reporting minimum inhibitory concentration (MIC) values to clinicians remains controversial. We surveyed clinicians to assess their knowledge and usage of MIC in clinical scenarios. The majority of respondents used MIC values to select antibiotic therapy, with a tendency to use those antibiotics with lower MICs, regardless of clinical appropriateness.
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21
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Jeong JH, Kweon OJ, Kim HR, Kim TH, Ha SM, Lee MK. A Novel Species of the Genus Arsenicicoccus Isolated From Human Blood Using Whole-Genome Sequencing. Ann Lab Med 2021; 41:323-327. [PMID: 33303718 PMCID: PMC7748104 DOI: 10.3343/alm.2021.41.3.323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/09/2020] [Accepted: 11/26/2020] [Indexed: 11/19/2022] Open
Abstract
Whole-genome sequencing (WGS) is an easily accessible and valuable tool in clinical microbiology, which can be used for identifying novel and rare species. We isolated gram-positive cocci from the blood of a pediatric patient, which could not be phenotypically identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) (BioMérieux, Marcy-l'Étoile, France). We could not identify the isolate to the species level using 16S ribosomal RNA (rRNA) sequencing. WGS was performed using the Illumina MiSeq platform (Illumina, San Diego, CA, USA); however, the subsequent genomic sequence database search using the TrueBac ID-Genome system (ChunLab, Inc., Seoul, Korea) did not yield any hits with an average nucleotide identity value >95.0%, which is the cut-off for species-level identification. Phylogenetic analysis suggested that the isolate belonged to a new Arsenicicoccus species, forming a subcluster with Arsenicicoccus bolidensis. Our data demonstrate that WGS allows a more accurate annotation of microbial genomes than other clinical microbiology tools, such as MALDI-TOF MS and 16S rRNA sequencing. This is the first report of the isolation of a novel Arsenicicoccus species from a clinical sample.
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Affiliation(s)
- Ji Hun Jeong
- Department of Laboratory Medicine, Daejeon Eulji Medical Center, Eulji University, Daejeon, Korea
| | - Oh Joo Kweon
- Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Hye Ryoun Kim
- Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Tae-Hyoung Kim
- Department of Urology, Chung-Ang University College of Medicine, Seoul, Korea
| | - Sung-Min Ha
- Department of Integrative Biology and Physiology, University of California, Los Angeles, USA
| | - Mi-Kyung Lee
- Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, Korea
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22
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Activity of β-Lactam Antibiotics against Metallo-β-Lactamase-Producing Enterobacterales in Animal Infection Models: a Current State of Affairs. Antimicrob Agents Chemother 2021; 65:AAC.02271-20. [PMID: 33782001 DOI: 10.1128/aac.02271-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Metallo-β-lactamases (MBLs) result in resistance to nearly all β-lactam antimicrobial agents, as determined by currently employed susceptibility testing methods. However, recently reported data demonstrate that variable and supraphysiologic zinc concentrations in conventional susceptibility testing media compared with physiologic (bioactive) zinc concentrations may be mediating discordant in vitro-in vivo MBL resistance. While treatment outcomes in patients appear suggestive of this discordance, these limited data are confounded by comorbidities and combination therapy. To that end, the goal of this review is to evaluate the extent of β-lactam activity against MBL-harboring Enterobacterales in published animal infection model studies and provide contemporary considerations to facilitate the optimization of current antimicrobials and development of novel therapeutics.
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23
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Banerjee R, Humphries R. Rapid Antimicrobial Susceptibility Testing Methods for Blood Cultures and Their Clinical Impact. Front Med (Lausanne) 2021; 8:635831. [PMID: 33777978 PMCID: PMC7987685 DOI: 10.3389/fmed.2021.635831] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/01/2021] [Indexed: 12/29/2022] Open
Abstract
Antimicrobial susceptibility testing (AST) of bacteria isolated in blood cultures is critical for optimal management of patients with sepsis. This review describes new and emerging phenotypic and genotypic AST methods and summarizes the evidence that implementation of these methods can impact clinical outcomes of patients with bloodstream infections.
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Affiliation(s)
- Ritu Banerjee
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Romney Humphries
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States
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Pseudomonas aeruginosa Susceptibility Patterns and Associated Clinical Outcomes in People with Cystic Fibrosis following Approval of Aztreonam Lysine for Inhalation. Antimicrob Agents Chemother 2021; 65:AAC.02327-20. [PMID: 33318007 PMCID: PMC8092527 DOI: 10.1128/aac.02327-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 12/06/2020] [Indexed: 11/20/2022] Open
Abstract
The approval of aztreonam lysine for inhalation solution (AZLI) raised concerns that additional antibiotic exposure would potentially affect the susceptibility profiles of Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients. This 5-year, prospective, observational study tracked susceptibility changes and clinical outcomes in CF patients in the United States with chronic P. aeruginosa infection. Sputum cultures were collected annually (2011 to 2016). The primary study endpoint was the proportion of subjects whose least susceptible P. aeruginosa isolate had an aztreonam MIC that was >8 μg/ml (parenteral breakpoint) and increased ≥4-fold compared with the least susceptible isolate from the previous year. Annualized data for pulmonary exacerbations, hospitalizations, and percent of predicted forced expiratory volume in 1 s (FEV1% predicted) were obtained from the CF Foundation Patient Registry and compared between subjects meeting and those not meeting the primary endpoint. A total of 510 subjects were enrolled; 334 (65%) completed the study. A consistent proportion of evaluable subjects (13 to 22%) met the primary endpoint each year, and AZLI use during the previous 12 months was not associated with meeting the primary endpoint. While the annual declines in lung function were comparable for subjects meeting and those not meeting the primary endpoint, more pulmonary exacerbations and hospitalizations were experienced by those who met it. The aztreonam susceptibility of P. aeruginosa remained consistent during the 5-year study. The relationship between P. aeruginosa isolate susceptibilities and clinical outcomes is complex; reduced susceptibility was not associated with an accelerated decline in lung function but was associated with more exacerbations and hospitalizations, likely reflecting increased overall antibiotic exposure. (This study has been registered at ClinicalTrials.gov under identifier NCT01375036.).
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The Minimum Inhibitory Concentration of Antibiotics: Methods, Interpretation, Clinical Relevance. Pathogens 2021; 10:pathogens10020165. [PMID: 33557078 PMCID: PMC7913839 DOI: 10.3390/pathogens10020165] [Citation(s) in RCA: 237] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/21/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Inefficiency of medical therapies used in order to cure patients with bacterial infections requires not only to actively look for new therapeutic strategies but also to carefully select antibiotics based on variety of parameters, including microbiological. Minimal inhibitory concentration (MIC) defines in vitro levels of susceptibility or resistance of specific bacterial strains to applied antibiotic. Reliable assessment of MIC has a significant impact on the choice of a therapeutic strategy, which affects efficiency of an infection therapy. In order to obtain credible MIC, many elements must be considered, such as proper method choice, adherence to labeling rules, and competent interpretation of the results. In this paper, two methods have been discussed: dilution and gradient used for MIC estimation. Factors which affect MIC results along with the interpretation guidelines have been described. Furthermore, opportunities to utilize MIC in clinical practice, with pharmacokinetic /pharmacodynamic parameters taken into consideration, have been investigated. Due to problems related to PK determination in individual patients, statistical estimation of the possibility of achievement of the PK/PD index, based on the Monte Carlo, was discussed. In order to provide comprehensive insights, the possible limitations of MIC, which scientists are aware of, have been outlined.
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Asbell PA, Sanfilippo CM, Sahm DF, DeCory HH. Trends in Antibiotic Resistance Among Ocular Microorganisms in the United States From 2009 to 2018. JAMA Ophthalmol 2021; 138:439-450. [PMID: 32271355 PMCID: PMC7146550 DOI: 10.1001/jamaophthalmol.2020.0155] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Question What are the antibiotic resistance profiles and trends among common ocular pathogens across the United States? Findings In this cross-sectional study of more than 6000 ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae collected between 2009 and 2018, methicillin resistance and multidrug resistance were prevalent among staphylococci. Antibiotic resistance profiles were mostly unchanged during 10 years. Meaning These in vitro antibiotic resistance data may assist clinicians in selecting appropriate antibiotics for treatment of ocular infections. Importance Antibiotic resistance in ocular infections can affect treatment outcomes. Surveillance data on evolving antibacterial susceptibility patterns inform the treatment of such infections. Objective To assess overall antibiotic resistance profiles and trends among bacterial isolates from ocular sources collected during 10 years. Design, Setting, and Participants This cross-sectional study of longitudinal data from the ongoing, nationwide, prospective, laboratory-based surveillance study, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study, included clinically relevant isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae cultured from patients with ocular infections at US centers from January 1, 2009, to December 31, 2018. Main Outcomes and Measures Minimum inhibitory concentrations were determined for various combinations of antibiotics and species. Odds ratios (ORs) were determined for concurrent antibiotic resistance; analysis of variance and χ2 tests were used to evaluate resistance rates by patient age and geographic region; Cochran-Armitage tests identified changing antibiotic susceptibility trends over time. Results A total of 6091 isolates (2189 S aureus, 1765 CoNS, 590 S pneumoniae, 767 P aeruginosa, and 780 H influenzae) from 6091 patients were submitted by 88 sites. Overall, 765 S aureus (34.9%) and 871 CoNS (49.3%) isolates were methicillin resistant and more likely to be concurrently resistant to macrolides (azithromycin: S aureus: OR, 18.34 [95% CI, 13.64-24.67]; CoNS: OR, 4.59 [95% CI, 3.72-5.66]), fluoroquinolones (ciprofloxacin: S aureus: OR, 22.61 [95% CI, 17.96-28.47]; CoNS: OR, 9.73 [95% CI, 7.63-12.40]), and aminoglycosides (tobramycin: S aureus: OR, 18.29 [95% CI, 13.21-25.32]; CoNS: OR, 6.28 [95% CI, 4.61-8.56]) compared with methicillin-susceptible isolates (P < .001 for all). Multidrug resistance was observed among methicillin-resistant S aureus (577 [75.4%]) and CoNS (642 [73.7%]) isolates. Antibiotic resistance among S pneumoniae isolates was highest for azithromycin (214 [36.3%]), whereas P aeruginosa and H influenzae isolates showed low resistance overall. Differences in antibiotic resistance were found among isolates by patient age (S aureus: F = 28.07, P < .001; CoNS: F = 11.46, P < .001) and geographic region (S aureus: F = 8.03, P < .001; CoNS: F = 4.79, P = .003; S pneumoniae: F = 8.14, P < .001; P aeruginosa: F = 4.32, P = .005). Small changes in antibiotic resistance were noted over time (≤2.5% per year), with decreases in resistance to oxacillin/methicillin (oxacillin: −2.16%; 95% CI, −3.91% to −0.41%; P < .001) and other antibiotics among S aureus isolates, a decrease in ciprofloxacin resistance among CoNS (−1.38%; 95% CI, −2.24% to −0.52%; P < .001), and an increase in tobramycin resistance among CoNS (0.71%; 95% CI, –0.29% to 1.71%; P = .03). Besifloxacin retained consistently low minimum inhibitory concentrations. Conclusions and Relevance Antibiotic resistance may be prevalent among staphylococcal isolates, particularly among older patients. In this study, a few small differences in antibiotic resistance were observed by geographic region or longitudinally.
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Affiliation(s)
- Penny A Asbell
- Department of Ophthalmology, The University of Tennessee Health Science Center, Memphis
| | | | - Daniel F Sahm
- International Health Management Associates Inc, Schaumburg, Illinois
| | - Heleen H DeCory
- Pharmaceutical Medical Affairs, Bausch + Lomb, Rochester, New York
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Use of Local Antibiogram Data and Antimicrobial Importance Ratings to Select Optimal Empirical Therapies for Urinary Tract Infections in Dogs and Cats. Antibiotics (Basel) 2020; 9:antibiotics9120924. [PMID: 33353226 PMCID: PMC7766990 DOI: 10.3390/antibiotics9120924] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
International and Australian veterinary antimicrobial use guidelines recommend amoxicillin or trimethoprim-sulfonamide (TMS) for the empirical treatment of sporadic urinary tract infections (UTIs) in dogs and cats. However, in practice, these antibiotics are rarely used, and no large-scale analyses have examined the antibiograms of bacteria isolated from UTIs to validate these recommendations in Australia. We analyzed five years of urine culture and antimicrobial susceptibility data from an Australian veterinary laboratory. The analysis included 6196 urinary isolates from dogs and cats, 78% of which were from samples submitted by first-opinion veterinary clinics. Escherichia coli, Enterococcus faecalis, Staphylococcus pseudintermedius and Proteus spp. were the most prevalent organisms. More than 80% of all isolated cocci were susceptible to amoxicillin, and more than 80% of bacilli were susceptible to TMS. A total of 94% of isolates were susceptible to at least one antimicrobial drug categorized as low-importance in Australia. The prevalence of multi-drug resistance (MDR) was highest in E. coli, at 9.7%; 84% of these MDR isolates were susceptible to amoxicillin-clavulanate. We performed population-level antimicrobial treatment simulations and proposed a novel method for integrating antimicrobial importance ratings with antibiogram data to optimize the selection of empirical therapy. Our findings support current guideline recommendations to use amoxicillin or TMS. We also found that bacterial morphology assisted with selection; amoxicillin was a better choice for cocci and TMS for bacilli.
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Variability in Zinc Concentration among Mueller-Hinton Broth Brands: Impact on Antimicrobial Susceptibility Testing of Metallo-β-Lactamase-Producing Enterobacteriaceae. J Clin Microbiol 2020; 58:JCM.02019-20. [PMID: 32999009 DOI: 10.1128/jcm.02019-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/27/2020] [Indexed: 01/13/2023] Open
Abstract
Zinc concentrations in cation-adjusted Mueller-Hinton broth (caMHB) from different manufacturers have been found to differ. Here, we evaluated the impact of utilizing different brands and lots of commercially available caMHB on the classification of the antimicrobial susceptibility of metallo-β-lactamase (MBL)-harboring Enterobacteriaceae We also evaluated the addition of EDTA to caMHB as a means of achieving zinc-limited media. Fifteen clinical Enterobacteriaceae isolates (harboring NDM [n = 7], VIM [n = 3], IMP [n = 2], or KPC [n = 3]) and nine different commercial lots from three caMHB manufacturers (Becton, Dickinson; Oxoid; and Sigma-Aldrich) were utilized. Zinc-limited media were prepared by the addition of EDTA at concentrations ranging from 3 to 300 μg/ml. Meropenem MICs were determined in triplicate for each lot of conventional caMHB and zinc-limited media by broth microdilution. The zinc concentration in each lot of conventional caMHB was determined by inductively coupled plasma mass spectrometry. Up to 8-fold differences in meropenem MICs were observed between the commercial lots, resulting in different classifications of susceptibility among MBL-harboring isolates. Mean zinc concentrations were highest among conventional Becton, Dickinson caMHB lots relative to those for Oxoid and Sigma-Aldrich broth. Among MBL-harboring isolates, the impact of EDTA on MICs was dependent on the lot, correlating with initial zinc availability (i.e., less MIC reduction with higher initial zinc concentrations), while MICs for KPC-harboring isolates were unchanged. In summary, zinc variability was observed among commercial lots of caMHB, resulting in different classifications of susceptibility among MBL-harboring Enterobacteriaceae The addition of EDTA at concentrations of ≥30 μg/ml was sufficient to provide a zinc-limited medium, resulting in MICs that reflect in vivo meropenem activity.
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Abbott IJ, Roberts JA, Meletiadis J, Peleg AY. Antimicrobial pharmacokinetics and preclinical in vitro models to support optimized treatment approaches for uncomplicated lower urinary tract infections. Expert Rev Anti Infect Ther 2020; 19:271-295. [PMID: 32820686 DOI: 10.1080/14787210.2020.1813567] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Urinary tract infections (UTIs) are extremely common. Millions of people, particularly healthy women, are affected worldwide every year. One-in-two women will have a recurrence within 12-months of an initial UTI. Inadequate treatment risks worsening infection leading to acute pyelonephritis, bacteremia and sepsis. In an era of increasing antimicrobial resistance, it is critical to provide optimized antimicrobial treatment. AREAS COVERED Literature was searched using PubMed and Google Scholar (up to 06/2020), examining the etiology, diagnosis and oral antimicrobial therapy for uncomplicated UTIs, with emphasis on urinary antimicrobial pharmacokinetics (PK) and the application of dynamic in vitro models for the pharmacodynamic (PD) profiling of pathogen response. EXPERT OPINION The majority of antimicrobial agents included in international guidelines were developed decades ago without well-described dose-response relationships. Microbiology laboratories still apply standard diagnostic methodology that has essentially remained unchanged for decades. Furthermore, it is uncertain how relevant standard in vitro susceptibility is for predicting antimicrobial efficacy in urine. In order to optimize UTI treatments, clinicians must exploit the urine-specific PK of antimicrobial agents. Dynamic in vitro models are valuable tools to examine the PK/PD and urodynamic variables associated with UTIs, while informing uropathogen susceptibility reporting, optimized dosing schedules, clinical trials and treatment guidelines.
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Affiliation(s)
- Iain J Abbott
- Department of Infectious Diseases, the Alfred Hospital and Central Clinical School, Monash University, Melbourne, Australia
| | - Jason A Roberts
- University of Queensland Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia.,School of Pharmacy, Centre for Translational Anti-infective Pharmacodynamics, The University of Queensland, Brisbane, Australia.,Department of Intensive Care Medicine, Royal Brisbane and Women's Hospital, Brisbane, Australia.,Division of Anaesthesiology Critical Care Emergency and Pain Medicine, Nîmes University Hospital, University of Montpellier, Nîmes, France
| | - Joseph Meletiadis
- Clinical Microbiology Laboratory, Attikon University Hospital, Medical School, National and Kapodistrian University of Athens, Haidari, Greece
| | - Anton Y Peleg
- Department of Infectious Diseases, the Alfred Hospital and Central Clinical School, Monash University, Melbourne, Australia.,Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Australia
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McDermott PF, Davis JJ. Predicting antimicrobial susceptibility from the bacterial genome: A new paradigm for one health resistance monitoring. J Vet Pharmacol Ther 2020; 44:223-237. [PMID: 33010049 DOI: 10.1111/jvp.12913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/25/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022]
Abstract
The laboratory identification of antibacterial resistance is a cornerstone of infectious disease medicine. In vitro antimicrobial susceptibility testing has long been based on the growth response of organisms in pure culture to a defined concentration of antimicrobial agents. By comparing individual isolates to wild-type susceptibility patterns, strains with acquired resistance can be identified. Acquired resistance can also be detected genetically. After many decades of research, the inventory of genes underlying antimicrobial resistance is well known for several pathogenic genera including zoonotic enteric organisms such as Salmonella and Campylobacter and continues to grow substantially for others. With the decline in costs for large scale DNA sequencing, it is now practicable to characterize bacteria using whole genome sequencing, including the carriage of resistance genes in individual microorganisms and those present in complex biological samples. With genomics, we can generate comprehensive, detailed information on the bacterium, the mechanisms of antibiotic resistance, clues to its source, and the nature of mobile DNA elements by which resistance spreads. These developments point to a new paradigm for antimicrobial resistance detection and tracking for both clinical and public health purposes.
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Affiliation(s)
- Patrick F McDermott
- Office of Research, Center for Veterinary Medicine, U.S. Food and Drug Administration, Laurel, MD, USA
| | - James J Davis
- Division of Data Science and Learning, Argonne National Laboratory, Argonne, IL, USA.,University of Chicago Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL, USA
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Is it time to move away from polymyxins?: evidence and alternatives. Eur J Clin Microbiol Infect Dis 2020; 40:461-475. [PMID: 33009595 DOI: 10.1007/s10096-020-04053-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/25/2020] [Indexed: 12/17/2022]
Abstract
Increasing burden of carbapenem resistance and resultant difficult-to-treat infections are of particular concern due to the lack of effective and safe treatment options. More recently, several new agents with activity against certain multidrug-resistant (MDR) and extensive drug-resistant (XDR) Gram-negative pathogens have been approved for clinical use. These include ceftazidime-avibactam, meropenem-vaborbactam, imipenem-cilastatin-relebactam, plazomicin, and cefiderocol. For the management of MBL infections, clinically used triple combination comprising ceftazidime-avibactam and aztreonam is hindered due to non-availability of antimicrobial susceptibility testing methods and lack of information on potential drug-drug interaction leading to PK changes impacting its safety and efficacy. Moreover, in several countries including Indian subcontinent and developing countries, these new agents are yet to be made available. Under these circumstances, polymyxins are the only last resort for the treatment of carbapenem-resistant infections. With the recent evidence of suboptimal PK/PD particularly in lung environment, limited efficacy and increased nephrotoxicity associated with polymyxin use, the Clinical and Laboratory Standards Institute (CLSI) has revised both colistin and polymyxin B breakpoints. Thus, polymyxins 'intermediate' breakpoint for Enterobacterales, P. aeruginosa, and Acinetobacter spp. are now set at ≤ 2 mg/L, implying limited clinical efficacy even for isolates with the MIC value 2 mg/L. This change has questioned the dependency on polymyxins in treating XDR infections. In this context, recently approved cefiderocol and phase 3 stage combination drug cefepime-zidebactam assume greater significance due to their potential to act as polymyxin-supplanting therapies.
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Waters VJ, Kidd TJ, Canton R, Ekkelenkamp MB, Johansen HK, LiPuma JJ, Bell SC, Elborn JS, Flume PA, VanDevanter DR, Gilligan P. Reconciling Antimicrobial Susceptibility Testing and Clinical Response in Antimicrobial Treatment of Chronic Cystic Fibrosis Lung Infections. Clin Infect Dis 2020; 69:1812-1816. [PMID: 31056660 DOI: 10.1093/cid/ciz364] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/29/2019] [Indexed: 01/28/2023] Open
Abstract
Median cystic fibrosis (CF) survival has increased dramatically over time due to several factors, including greater availability and use of antimicrobial therapies. During the progression of CF lung disease, however, the emergence of multidrug antimicrobial resistance can limit treatment effectiveness, threatening patient longevity. Current planktonic-based antimicrobial susceptibility testing lacks the ability to predict clinical response to antimicrobial treatment of chronic CF lung infections. There are numerous reasons for these limitations including bacterial phenotypic and genotypic diversity, polymicrobial interactions, and impaired antibiotic efficacy within the CF lung environment. The parallels to other chronic diseases such as non-CF bronchiectasis are discussed as well as research priorities for moving forward.
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Affiliation(s)
- Valerie J Waters
- Division of Infectious Diseases, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Canada
| | - Timothy J Kidd
- School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Australia
| | - Rafael Canton
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
| | - Miquel B Ekkelenkamp
- Department of Medical Microbiology, University Medical Center Utrecht, The Netherlands
| | - Helle Krogh Johansen
- Department of Clinical Microbiology, Rigshospitalet, Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - John J LiPuma
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor
| | - Scott C Bell
- Department of Thoracic Medicine, Prince Charles Hospital and QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - J Stuart Elborn
- Imperial College Hospital, Queen's University Belfast, Northern Ireland
| | - Patrick A Flume
- Departments of Medicine and Pediatrics, Medical University of South Carolina, Charleston
| | - Donald R VanDevanter
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Peter Gilligan
- Department of Pathology-Laboratory Medicine, University of North Carolina School of Medicine, Chapel Hill
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Sinha MS, Powers JH, Kesselheim AS. The Wrong Cure: Financial Incentives for Unimpressive New Antibiotics. J Infect Dis 2020; 223:1506-1509. [PMID: 32827433 DOI: 10.1093/infdis/jiaa536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 08/18/2020] [Indexed: 01/26/2023] Open
Abstract
Though antimicrobial resistance is a public health concern, the basis of approval for many new antibiotics does not distinguish them from older products. We suggest a more tailored incentive structure for antibiotic development, focused on clinical benefit and patient outcomes.
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Affiliation(s)
- Michael S Sinha
- Program on Regulation, Therapeutics, and Law, Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.,Harvard-MIT Center for Regulatory Science, Harvard Medical School, Boston, Massachusetts, USA
| | - John H Powers
- George Washington University School of Medicine, Washington, District of Columbia, USA
| | - Aaron S Kesselheim
- Program on Regulation, Therapeutics, and Law, Division of Pharmacoepidemiology and Pharmacoeconomics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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Clarelli F, Palmer A, Singh B, Storflor M, Lauksund S, Cohen T, Abel S, Abel zur Wiesch P. Drug-target binding quantitatively predicts optimal antibiotic dose levels in quinolones. PLoS Comput Biol 2020; 16:e1008106. [PMID: 32797079 PMCID: PMC7449454 DOI: 10.1371/journal.pcbi.1008106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 08/26/2020] [Accepted: 06/30/2020] [Indexed: 11/19/2022] Open
Abstract
Antibiotic resistance is rising and we urgently need to gain a better quantitative understanding of how antibiotics act, which in turn would also speed up the development of new antibiotics. Here, we describe a computational model (COMBAT-COmputational Model of Bacterial Antibiotic Target-binding) that can quantitatively predict antibiotic dose-response relationships. Our goal is dual: We address a fundamental biological question and investigate how drug-target binding shapes antibiotic action. We also create a tool that can predict antibiotic efficacy a priori. COMBAT requires measurable biochemical parameters of drug-target interaction and can be directly fitted to time-kill curves. As a proof-of-concept, we first investigate the utility of COMBAT with antibiotics belonging to the widely used quinolone class. COMBAT can predict antibiotic efficacy in clinical isolates for quinolones from drug affinity (R2>0.9). To further challenge our approach, we also do the reverse: estimate the magnitude of changes in drug-target binding based on antibiotic dose-response curves. We overexpress target molecules to infer changes in antibiotic-target binding from changes in antimicrobial efficacy of ciprofloxacin with 92-94% accuracy. To test the generality of our approach, we use the beta-lactam ampicillin to predict target molecule occupancy at MIC from antimicrobial action with 90% accuracy. Finally, we apply COMBAT to predict antibiotic concentrations that can select for resistance due to novel resistance mutations. Using ciprofloxacin and ampicillin as well defined test cases, our work demonstrates that drug-target binding is a major predictor of bacterial responses to antibiotics. This is surprising because antibiotic action involves many additional effects downstream of drug-target binding. In addition, COMBAT provides a framework to inform optimal antibiotic dose levels that maximize efficacy and minimize the rise of resistant mutants.
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Affiliation(s)
- Fabrizio Clarelli
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
- Department of Biology, Eberly College of Science, The Pennsylvania State University, University Park, PA, United States of America
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States of America
| | - Adam Palmer
- Department of Pharmacology, Computational Medicine Program, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Bhupender Singh
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
| | - Merete Storflor
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
- Department of Veterinary and Biomedical Sciences, College of Agricultural Sciences, The Pennsylvania State University, PA, United States of America
| | - Silje Lauksund
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
| | - Ted Cohen
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States of America
| | - Sören Abel
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States of America
- Department of Veterinary and Biomedical Sciences, College of Agricultural Sciences, The Pennsylvania State University, PA, United States of America
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, Oslo, Norway
| | - Pia Abel zur Wiesch
- Department of Pharmacy, Faculty of Health Sciences, UiT—The Arctic University of Norway, Tromsø, Norway
- Department of Biology, Eberly College of Science, The Pennsylvania State University, University Park, PA, United States of America
- Center for Infectious Disease Dynamics, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States of America
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, Oslo, Norway
- * E-mail:
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Friberg C, Haaber JK, Vestergaard M, Fait A, Perrot V, Levin BR, Ingmer H. Human antimicrobial peptide, LL-37, induces non-inheritable reduced susceptibility to vancomycin in Staphylococcus aureus. Sci Rep 2020; 10:13121. [PMID: 32753585 PMCID: PMC7403302 DOI: 10.1038/s41598-020-69962-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 06/08/2020] [Indexed: 11/09/2022] Open
Abstract
Antimicrobial peptides (AMPs) are central components of the innate immune system providing protection against pathogens. Yet, serum and tissue concentrations vary between individuals and with disease conditions. We demonstrate that the human AMP LL-37 lowers the susceptibility to vancomycin in the community-associated methicillin-resistant S. aureus (CA-MRSA) strain FPR3757 (USA300). Vancomycin is used to treat serious MRSA infections, but treatment failures occur despite MRSA strains being tested susceptible according to standard susceptibility methods. Exposure to physiologically relevant concentrations of LL-37 increased the minimum inhibitory concentration (MIC) of S. aureus towards vancomycin by 75%, and resulted in shortened lag-phase and increased colony formation at sub-inhibitory concentrations of vancomycin. Computer simulations using a mathematical antibiotic treatment model indicated that a small increase in MIC might decrease the efficacy of vancomycin in clearing a S. aureus infection. This prediction was supported in a Galleria mellonella infection model, where exposure of S. aureus to LL-37 abolished the antimicrobial effect of vancomycin. Thus, physiological relevant concentrations of LL-37 reduce susceptibility to vancomycin, indicating that tissue and host specific variations in LL-37 concentrations may influence vancomycin susceptibility in vivo.
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Affiliation(s)
- Cathrine Friberg
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
- Novo Nordisk, Hagedornsvej 1, 2820, Gentofte, Denmark
| | - Jakob Krause Haaber
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
- SNIPRbiome, Lerso Parkallé 44, 2100, Copenhagen, Denmark
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | - Anaëlle Fait
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark
| | | | - Bruce R Levin
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Stigbøjlen 4, 1870, Frederiksberg C, Denmark.
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Brisca G, La Valle A, Campanello C, Pacetti M, Severino M, Losurdo G, Palmieri A, Buffoni I, Renna S. Listeria meningitis complicated by hydrocephalus in an immunocompetent child: case report and review of the literature. Ital J Pediatr 2020; 46:111. [PMID: 32741364 PMCID: PMC7397632 DOI: 10.1186/s13052-020-00873-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023] Open
Abstract
Background Listeria monocytogenes is a Gram-positive bacteria transmitted to human by animal stools, contaminated water and food. In children, Listeria monocytogenes typically affects newborns and immunocompromised patients often leading to invasive syndromes including sepsis, brain abscesses, meningitis, meningoencephalitis and rhombencephalitis. In healthy and immunocompetent children, Listeria meningitis is rare, but can progress rapidly and may be associated with severe complications (hydrocephalus, ventriculitis, cranial nerves palsy and cerebrospinal abscesses) and high mortality rate. Case presentation We describe a very uncommon case of meningoencephalitis due to Listeria monocytogenes in a 11-month-old immunocompetent girl. Cerebrospinal fluid (CSF) culture was positive on the second day. Antibiotic therapy was promptly started but the disease was complicated by neurological deterioration and decompensated hydrocephalus. The child required a very demanding pediatric and neurosurgical management and was discharged after 40 days without major sequelae. Conclusion Listeria is difficult to isolate and it is not susceptible to first-line treatment for bacterial meningitis with extended-spectrum cephalosporins. Early recognition is therefore crucial for a positive outcome. Pediatricians have to perform close clinical monitoring of these children and be aware of possible complications. A review of all cases of Listeria meningitis complicated by hydrocephalus in healthy children has been performed, to provide an overview on clinical features, treatment options and outcome.
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Affiliation(s)
- Giacomo Brisca
- Pediatric Emergency Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy.
| | - Alberto La Valle
- Pediatric Emergency Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Claudia Campanello
- Pediatric Emergency Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Mattia Pacetti
- Department of Neurosurgery, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Mariasavina Severino
- Neuroradiology Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Giuseppe Losurdo
- Infectious Disease Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Antonella Palmieri
- Pediatric Emergency Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Isabella Buffoni
- Neonatal and Pediatric Intensive Care Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Salvatore Renna
- Pediatric Emergency Unit, IRCCS Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147, Genoa, Italy
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Teimouri H, Kolomeisky AB. Theoretical investigation of stochastic clearance of bacteria: first-passage analysis. J R Soc Interface 2020; 16:20180765. [PMID: 30890051 DOI: 10.1098/rsif.2018.0765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Understanding mechanisms of bacterial eradication is critically important for overcoming failures of antibiotic treatments. Current studies suggest that the clearance of large bacterial populations proceeds deterministically, while for smaller populations, the stochastic effects become more relevant. Here, we develop a theoretical approach to investigate the bacterial population dynamics under the effect of antibiotic drugs using a method of first-passage processes. It allows us to explicitly evaluate the most important characteristics of bacterial clearance dynamics such as extinction probabilities and extinction times. The new meaning of minimal inhibitory concentrations for stochastic clearance of bacterial populations is also discussed. In addition, we investigate the effect of fluctuations in population growth rates on the dynamics of bacterial eradication. It is found that extinction probabilities and extinction times generally do not correlate with each other when random fluctuations in the growth rates are taking place. Unexpectedly, for a significant range of parameters, the extinction times increase due to these fluctuations, indicating a slowing in the bacterial clearance dynamics. It is argued that this might be one of the initial steps in the pathway for the development of antibiotic resistance. Furthermore, it is suggested that extinction times is a convenient measure of bacterial tolerance.
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Affiliation(s)
- Hamid Teimouri
- 1 Department of Chemistry, Rice University , Houston, TX , USA.,3 Center for Theoretical Biological Physics, Rice University , Houston, TX , USA
| | - Anatoly B Kolomeisky
- 1 Department of Chemistry, Rice University , Houston, TX , USA.,2 Department of Chemical and Biomolecular Engineering, Rice University , Houston, TX , USA.,3 Center for Theoretical Biological Physics, Rice University , Houston, TX , USA
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Knabl L, Lass-Flörl C. Antifungal susceptibility testing in Candida species: current methods and promising new tools for shortening the turnaround time. Expert Rev Anti Infect Ther 2020; 18:779-787. [PMID: 32324090 DOI: 10.1080/14787210.2020.1760841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Invasive fungal diseases (IFDs) have received attention as an emerging public health threat, are difficult to diagnose and to treat, and are associated with substantial morbidity and mortality. The standard of care in IFD management requires an early and targeted antifungal treatment, hence covers - amongst others - species identification and antifungal susceptibility testing (AFST). AREAS COVERED This review gives an overview of methods currently applied in AFST and highlights promising new tools for shortening the turnaround time focusing on Candida species. EXPERT OPINION The performance of the broth microdilution reference methods for AFST is not suitable for daily laboratory practice as they are too labor-intensive and time-consuming. Other conventional approaches such as disk diffusion assays, epsilometer tests, colorimetric or automated approaches are easier in handling, and in part, show good correlations with the reference methods. Promising results for shortening the turnaround time in providing MIC data or resistance detection include matrix-assisted laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF MS) assisted AFST, molecular-based techniques and modified conventional approaches applying direct inoculation methods. These underlying AFST concepts are promising but in part completely different, have their own advantages and disadvantages, and need further clinical validation.
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Affiliation(s)
- Ludwig Knabl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck , Innsbruck, Austria
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck , Innsbruck, Austria
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Richter A, Feßler AT, Böttner A, Köper LM, Wallmann J, Schwarz S. Reasons for antimicrobial treatment failures and predictive value of in-vitro susceptibility testing in veterinary practice: An overview. Vet Microbiol 2020; 245:108694. [PMID: 32456814 DOI: 10.1016/j.vetmic.2020.108694] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/19/2020] [Accepted: 04/14/2020] [Indexed: 10/24/2022]
Abstract
The choice of the most suitable antimicrobial agent for the treatment of an animal suffering from a bacterial infection is a complex issue. The results of bacteriological diagnostics and the in-vitro antimicrobial susceptibility testing (AST) provide guidance of potentially suitable antimicrobials. However, harmonized AST methods, veterinary-specific interpretive criteria and quality control ranges, which are essential to conduct AST in-vitro and to evaluate the corresponding results lege artis, are not available for all antimicrobial compounds, bacterial pathogens, animal species and sites of infection of veterinary relevance. Moreover, the clinical benefit of an antimicrobial agent (defined as its in vivo efficacy) is not exclusively dependent on the in-vitro susceptibility of the target pathogen. Apart from the right choice of an antibacterial drug with suitable pharmacokinetic properties and an appropriate pharmaceutical formulation, the success of treatment depends substantially on its adequate use. Even if this is ensured and in-vitro susceptibility confirmed, an insufficient improvement of clinical signs might be caused by biofilm-forming bacteria, persisters, or specific physicochemical conditions at the site of infection, such as pH value, oxygen partial pressure and perfusion rate. This review summarizes relevant aspects that have an impact on the predictive value of in-vitro AST and points out factors, potentially leading to an ineffective outcome of antibacterial treatment in veterinary practice. Knowing the reasons of inadequate beneficial effects can help to understand possible discrepancies between in-vitro susceptibility and in vivo efficacy and aid in undertaking strategies for an avoidance of treatment failures.
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Affiliation(s)
- Angelika Richter
- Institute of Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, University of Leipzig, Leipzig, Germany.
| | - Andrea T Feßler
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | | | | | - Jürgen Wallmann
- Federal Office of Consumer Protection and Food Safety, Berlin, Germany
| | - Stefan Schwarz
- Institute of Microbiology and Epizootics, Centre of Infection Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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Urine Cultures in Pyelonephritis: An Overstated Requirement. Ann Emerg Med 2020; 74:598-599. [PMID: 31543126 DOI: 10.1016/j.annemergmed.2019.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Indexed: 11/23/2022]
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Cantón R, Oliver A, Alós JI, de Benito N, Bou G, Campos J, Calvo J, Canut A, Castillo J, Cercenado E, Domínguez MÁ, Fernández-Cuenca F, Guinea J, Larrosa N, Liñares J, López-Cerero L, López-Navas A, Marco F, Mirelis B, Moreno-Romo MÁ, Morosini MI, Navarro F, Oteo J, Pascual Á, Pérez-Trallero E, Pérez-Vázquez M, Soriano A, Torres C, Vila J, Martínez-Martínez L. Recommendations of the Spanish Antibiogram Committee (COESANT) for selecting antimicrobial agents and concentrations for in vitro susceptibility studies using automated systems. Enferm Infecc Microbiol Clin 2020; 38:182-187. [PMID: 30878313 DOI: 10.1016/j.eimc.2019.01.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 01/06/2019] [Indexed: 02/05/2023]
Abstract
Automated antimicrobial susceptibility testing devices are widely implemented in clinical microbiology laboratories in Spain, mainly using EUCAST (European Committee on Antimicrobial Susceptibility Testing) breakpoints. In 2007, a group of experts published recommendations for including antimicrobial agents and selecting concentrations in these systems. Under the patronage of the Spanish Antibiogram Committee (Comité Español del Antibiograma, COESANT) and the Study Group on Mechanisms of Action and Resistance to Antimicrobial Agents (GEMARA) from the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), and aligned with the Spanish National Plan against Antimicrobial Resistance (PRAN), a group of experts have updated this document. The main modifications from the previous version comprise the inclusion of new antimicrobial agents, adaptation of the ranges of concentrations to cover the EUCAST breakpoints and epidemiological cut-off values (ECOFFs), and the inference of new resistance mechanisms. This proposal should be considered by different manufacturers and users when designing new panels or cards. In addition, recommendations for selective reporting are also included. With this approach, the implementation of EUCAST breakpoints will be easier, increasing the quality of antimicrobial susceptibility testing data and their microbiological interpretation. It will also benefit epidemiological surveillance studies as well as the clinical use of antimicrobials aligned with antimicrobial stewardship programs.
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Affiliation(s)
- Rafael Cantón
- Servicio de Microbiología, Hospital Universtario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain.
| | - Antonio Oliver
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain
| | - Juan Ignacio Alós
- Servicio de Microbiología, Hospital Universitario de Getafe, Madrid, Spain
| | - Natividad de Benito
- Unidad de Enfermedades Infecciosas, Hospital de la Santa Creu i Sant Pau, Instituto de Investigación Biomédica Sant Pau (IIB Sant Pau), Universitat Autònoma, Barcelona, Spain
| | - Germán Bou
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología-INIBIC, Complejo Hospitalario Universitario A Coruña, A Coruña, Spain
| | - José Campos
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Jorge Calvo
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla and Instituto de Investigación Marqués de Valdecilla (IDIVAL), Santander, Spain
| | - Andrés Canut
- Servicio de Microbiología, Hospital Universitario de Álava, Vitoria, Spain
| | - Javier Castillo
- Servicio de Microbiología, Hospital Clínico Universitario, Zaragoza, Spain
| | - Emilia Cercenado
- Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Maria Ángeles Domínguez
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universitario de Bellvitge, Barcelona, Spain
| | - Felipe Fernández-Cuenca
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Virgen Macarena, Sevilla, Spain
| | - Jesús Guinea
- Servicio de Microbiología y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | - Nieves Larrosa
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universitario Vall d'Hebron, Barcelona, Spain
| | - Josefina Liñares
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Universtario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Lorena López-Cerero
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Virgen Macarena, Sevilla, Spain
| | - Antonio López-Navas
- Agencia Española de Medicamentos y Productos Sanitarios (AEMPS), Madrid, Spain
| | - Francesc Marco
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Microbiología, Centro de Diagnóstico Biomédico (CDB), Hospital Clínic, Universidad de Barcelona, and ISGlobal, Barcelona, Spain
| | - Beatriz Mirelis
- Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | | | - María Isabel Morosini
- Servicio de Microbiología, Hospital Universtario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - Ferran Navarro
- Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Jesús Oteo
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Álvaro Pascual
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Servicio de Microbiología, Hospital Virgen Macarena, Sevilla, Spain
| | - Emilio Pérez-Trallero
- Servicio de Microbiología, Hospital Universitario Donostia-IIS Biodonostia, San Sebastián, Spain
| | - María Pérez-Vázquez
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Laboratorio de Referencia e Investigación en Resistencia a Antibióticos e Infecciones Relacionadas con la Asistencia Sanitaria, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Alex Soriano
- Servicio de Enfermedades Infecciosas, Hospital Clínic, Barcelona, Spain
| | - Carmen Torres
- Facultad de Ciencias y Tecnología, Área de Bioquímica y Biología Molecular, Universidad de La Rioja, Logroño, Spain
| | - Jordi Vila
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Microbiología, Centro de Diagnóstico Biomédico (CDB), Hospital Clínic, Universidad de Barcelona, and ISGlobal, Barcelona, Spain
| | - Luis Martínez-Martínez
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain; Unidad de Gestión Clínica de Microbiología, Hospital Reina Sofía, Departamento de Microbiología, Universidad de Córdoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
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Alonso JDM, Rosa GDS, Santos B, Guerra S, Ribeiro M, Watanabe MJ, Alves A, Rodrigues C, Takahira RK, Hussni CA. Adjuvant intraperitoneal ceftriaxone in the treatment of septic peritonitis in horses. Vet Rec 2020; 187:e29. [PMID: 32234866 DOI: 10.1136/vr.105570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 03/10/2020] [Accepted: 03/15/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND Intraperitoneal administration of ceftriaxone maintains therapeutic abdominal concentrations for 24 hours in healthy horses. Therefore, it is a possible treatment for septic peritonitis. The aim of this study was to evaluate the efficacy of ceftriaxone as an adjuvant treatment in horses with septic peritonitis. METHODS Twenty-six horses with clinical signs, sonography and/or laboratory findings of septic peritonitis were included. Peritoneal fluid was collected for microbiological culture and in vitro microbial sensitivity profile assessment. Daily intraperitoneal administration of ceftriaxone (25 mg/kg) was initiated with supportive and systemic antimicrobial treatment. The animals were divided into three groups: group 1-gastrointestinal tract injuries and abdominal surgery (excluding perforations/ruptures); group 2-not related to changes in the gastrointestinal tract; group 3-secondary to intestinal rupture and/or faeces contamination. RESULTS The mean success rate of the treatment was 77 per cent (20/26 animals), with success rates of 84.6 per cent in group 1; 87.5 per cent, group 2; and 40 per cent, group 3. CONCLUSIONS This is the first study to report adjuvant intraperitoneal treatment ceftriaxone for septic peritonitis in horses and indicates that this treatment can successfully treat septic peritonitis in horses.
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Affiliation(s)
- Juliana de Moura Alonso
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Gustavo Dos Santos Rosa
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Bruna Santos
- Department of Veterinary Clinics, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Simony Guerra
- Department of Veterinary Hygiene and Public Health, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Márcio Ribeiro
- Department of Veterinary Hygiene and Public Health, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Marcos Jun Watanabe
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - A Alves
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Celso Rodrigues
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Regina Kiomi Takahira
- Department of Veterinary Clinics, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
| | - Carlos Alberto Hussni
- Department of Veterinary Surgery and Anaesthesiology, Univ Estadual Paulista (UNESP)-School of Veterinary Medicine and Animal Science (FMVZ), Botucatu, Brazil
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Mattoo TK, Asmar BI. Annotations on Emerging Concerns About Antibiotic-Resistant Urinary Tract Infection. Pediatrics 2020; 145:peds.2019-3512. [PMID: 31953315 DOI: 10.1542/peds.2019-3512] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/13/2019] [Indexed: 11/24/2022] Open
Affiliation(s)
| | - Basim I Asmar
- Infectious Diseases, Department of Pediatrics, School of Medicine, Wayne State University and Children's Hospital of Michigan, Detroit, Michigan
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Orazi G, O'Toole GA. "It Takes a Village": Mechanisms Underlying Antimicrobial Recalcitrance of Polymicrobial Biofilms. J Bacteriol 2019; 202:e00530-19. [PMID: 31548277 PMCID: PMC6932244 DOI: 10.1128/jb.00530-19] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chronic infections are frequently caused by polymicrobial biofilms. Importantly, these infections are often difficult to treat effectively in part due to the recalcitrance of biofilms to antimicrobial therapy. Emerging evidence suggests that polymicrobial interactions can lead to dramatic and unexpected changes in the ability of antibiotics to eradicate biofilms and often result in decreased antimicrobial efficacy in vitro In this review, we discuss the influence of polymicrobial interactions on the antibiotic susceptibility of biofilms, and we highlight the studies that first documented the shifted antimicrobial susceptibilities of mixed-species cultures. Recent studies have identified several mechanisms underlying the recalcitrance of polymicrobial biofilm communities, including interspecies exchange of antibiotic resistance genes, β-lactamase-mediated inactivation of antibiotics, changes in gene expression induced by metabolites and quorum sensing signals, inhibition of the electron transport chain, and changes in properties of the cell membrane. In addition to elucidating multiple mechanisms that contribute to the altered drug susceptibility of polymicrobial biofilms, these studies have uncovered novel ways in which polymicrobial interactions can impact microbial physiology. The diversity of findings discussed highlights the importance of continuing to investigate the efficacy of antibiotics against biofilm communities composed of different combinations of microbial species. Together, the data presented here illustrate the importance of studying microbes as part of mixed-species communities rather than in isolation. In light of our greater understanding of how interspecies interactions alter the efficacy of antimicrobial agents, we propose that the methods for measuring the drug susceptibility of polymicrobial infections should be revisited.
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Affiliation(s)
- Giulia Orazi
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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Santos HCD, Vieira DS, Yamamoto SM, Costa MM, Sá MC, Silva EM, Silva TM. Antimicrobial activity of propolis extract fractions against Staphylococcus spp. isolated from goat mastitis. PESQUISA VETERINÁRIA BRASILEIRA 2019. [DOI: 10.1590/1678-5150-pvb-5940] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
ABSTRACT: The indiscriminate use of antibiotics in the treatment of caprine mastitis causes the appearance of resistant microorganisms, besides leaving residues in milk, putting at risk to human health. In this way, propolis is an alternative in the treatment of diseases because it has antimicrobial activity, mainly because of the presence of flavonoids in its composition. The aim of this study was to evaluate the antimicrobial potential of propolis to Staphylococcus spp. Isolated from cases of goat mastitis and qualify the crude ethanoic extract by high performance liquid chromatography (HPLC). In this study, the minimum bactericidal concentration values of propolis extracts in ethanol, ethyl acetate and hexane showed that the best concentrations capable of promoting the highest mortality of the isolates of Staphylococcus spp. from mastitis in goats, were 6250, 3125 and 1562.5μg/mL, respectively. By the microplate adherence test, it was found that 20.78% isolates were not able to form biofilm, 14.70% were classified as moderate and 64.70% were weak and none as a strong biofilm producer. Propolis in its different diluents was able to affect the formation of biofilm and showed a pronounced marked antimicrobial activity against Staphylococcus spp. strains and may be indicated for use in in vivo studies.
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Affiliation(s)
| | | | | | | | - Maria C.A. Sá
- Universidade Federal do Vale do São Francisco, Brazil
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Somayaji R, Goss CH. Duration of antibiotic therapy in non-cystic fibrosis bronchiectasis. CURRENT PULMONOLOGY REPORTS 2019; 8:160-165. [PMID: 31875166 PMCID: PMC6929711 DOI: 10.1007/s13665-019-00235-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW a)We conducted a review of the current evidence relating to antibiotic duration in the short and long-term management of non-cystic fibrosis bronchiectasis. RECENT FINDINGS b)In non-cystic fibrosis pulmonary exacerbations, evidence is primarily based on expert consensus and recent guidelines recommend antibiotic durations of approximately 14 days. Chronic antibiotics (oral or inhaled) are recommended in patients with frequent exacerbations or with chronic Pseudomonas aeruginosa airways infection. Macrolides are the best studied therapies for long-term use with evidence for effect limited to a 12 month duration. Encouragingly, there are increased efforts to develop registries and conduct larger population level studies to improve patient care. SUMMARY c)There is a paucity of evidence for optimal antibiotic strategies in exacerbations and chronic maintenance in persons with non-cystic fibrosis bronchiectasis. Rationally designed studies which utilize a registry and population-based approach will be critical to build evidence-based strategies to optimize management of non-cystic fibrosis bronchiectasis.
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Affiliation(s)
- R Somayaji
- Departments of Medicine and Microbiology, Immunology & Infectious Disease, University of Calgary, Calgary, Alberta CA
| | - C H Goss
- Departments of Medicine and Pediatrics, University of Washington School of Medicine, Seattle WA
- CFF Therapeutics Development Network Coordinating Center, Seattle Children's Research Institute, Seattle WA
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Miller RA, Salmon P, Sharkey M. Approaches to developing judicious uses of veterinary antibacterial drugs. J Vet Pharmacol Ther 2019; 44:201-206. [PMID: 31777967 DOI: 10.1111/jvp.12828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/17/2019] [Accepted: 11/10/2019] [Indexed: 11/30/2022]
Abstract
Development of new veterinary antibacterials is an important and challenging endeavor. Global recognition of antimicrobial resistance as a threat across human, animal, plant, food, and environmental sectors has increased the level of scrutiny on veterinary antibacterial use. Rigorous scientific evaluation of these products has and continues to be the underpinning of effectiveness evaluations and how hazards are identified, characterized, and ultimately used to make evidence-based and risk-based safety decisions. Some scientific factors commonly considered in the development of veterinary antibacterials include the pathogenesis and sequelae of the indicated disease, clinical and bacteriological improvement, dosage regimen (dose amount, route, duration, frequency), and antimicrobial-resistance qualitative risk assessments. Key discussion areas covered are how culture and susceptibility testing help determine if antibacterial effects are primarily responsible for clinical improvement and how pharmacokinetic and pharmacodynamic data can help predict success, aid in defining an adequate dosage regimen, and help minimize resistance emergence and spread.
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Affiliation(s)
- Ron A Miller
- Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Drug Evaluation, Division of Human Food Safety, Rockville, Maryland
| | - Paulette Salmon
- Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Drug Evaluation, Division of Therapeutic Drugs for Food Animals, Rockville, Maryland
| | - Michele Sharkey
- Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Drug Evaluation, Division of Therapeutic Drugs for Non-Food Animals, Rockville, Maryland
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Evaluation of Immunocompetent Urinary Tract Infected Balb/C Mouse Model For the Study of Antibiotic Resistance Development Using Escherichia Coli CFT073 Infection. Antibiotics (Basel) 2019; 8:antibiotics8040170. [PMID: 31569374 PMCID: PMC6963567 DOI: 10.3390/antibiotics8040170] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 01/12/2023] Open
Abstract
Urinary tract infections (UTI) are common worldwide and are becoming increasingly difficult to treat because of the development of antibiotic resistance. Immunocompetent murine models of human UTI have been used to study pathogenesis and treatment but not for investigating resistance development after treatment with antibiotics. In this study, intravesical inoculation of uropathogenic Escherichia coli CFT073 in immunocompetent Balb/c mice was used as a model of human UTI. The value of the model in investigating antibiotic exposure on in vivo emergence of antibiotic resistance was examined. Experimentally infected mice were treated with 20 or 200 mg/kg ampicillin, 5 or 50 mg/kg ciprofloxacin, or 100 or 1000 mg/kg of fosfomycin. Ampicillin and ciprofloxacin were given twice daily at 8 h intervals, and fosfomycin was given once daily. Antibiotic treatment began 24 h after bacterial inoculation and ended after 72 h following the initial treatment. Although minimum inhibitory concentrations (MIC) for the experimental strain of E. coli were exceeded at peak concentrations in tissues and consistently in urine, low levels of bacteria persisted in tissues in all experiments. E. coli from bladder tissue, kidney, and urine grew on plates containing 1× MIC of antibiotic, but none grew at 3× MIC. This model is not suitable for studying emergent resistance but might serve to examine bacterial persistence.
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Martinecz A, Clarelli F, Abel S, Abel Zur Wiesch P. Reaction Kinetic Models of Antibiotic Heteroresistance. Int J Mol Sci 2019; 20:E3965. [PMID: 31443146 PMCID: PMC6719119 DOI: 10.3390/ijms20163965] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 11/16/2022] Open
Abstract
Bacterial heteroresistance (i.e., the co-existence of several subpopulations with different antibiotic susceptibilities) can delay the clearance of bacteria even with long antibiotic exposure. Some proposed mechanisms have been successfully described with mathematical models of drug-target binding where the mechanism's downstream of drug-target binding are not explicitly modeled and subsumed in an empirical function, connecting target occupancy to antibiotic action. However, with current approaches it is difficult to model mechanisms that involve multi-step reactions that lead to bacterial killing. Here, we have a dual aim: first, to establish pharmacodynamic models that include multi-step reaction pathways, and second, to model heteroresistance and investigate which molecular heterogeneities can lead to delayed bacterial killing. We show that simulations based on Gillespie algorithms, which have been employed to model reaction kinetics for decades, can be useful tools to model antibiotic action via multi-step reactions. We highlight the strengths and weaknesses of current models and Gillespie simulations. Finally, we show that in our models, slight normally distributed variances in the rates of any event leading to bacterial death can (depending on parameter choices) lead to delayed bacterial killing (i.e., heteroresistance). This means that a slowly declining residual bacterial population due to heteroresistance is most likely the default scenario and should be taken into account when planning treatment length.
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Affiliation(s)
- Antal Martinecz
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Fabrizio Clarelli
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
| | - Sören Abel
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway
- Centre for Molecular Medicine Norway, P.O. Box 1137, Blindern, 0318 Oslo, Norway
| | - Pia Abel Zur Wiesch
- Department of Pharmacy, Faculty of Health Sciences, UiT-The Arctic University of Norway, 9037 Tromsø, Norway.
- Centre for Molecular Medicine Norway, P.O. Box 1137, Blindern, 0318 Oslo, Norway.
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Phee LM, Kloprogge F, Morris R, Barrett J, Wareham DW, Standing JF. Pharmacokinetic-pharmacodynamic modelling to investigate in vitro synergy between colistin and fusidic acid against MDR Acinetobacter baumannii. J Antimicrob Chemother 2019; 74:961-969. [PMID: 30624656 PMCID: PMC6419616 DOI: 10.1093/jac/dky524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/15/2018] [Accepted: 11/16/2018] [Indexed: 12/02/2022] Open
Abstract
Objectives The potential for synergy between colistin and fusidic acid in the treatment of MDR Acinetobacter baumannii has recently been shown. The aim of this study was to perform an extensive in vitro characterization of this effect using pharmacokinetic-pharmacodynamic modelling (PKPD) of time–kill experiments in order to estimate clinical efficacy. Methods For six clinical strains, 312 individual time–kill experiments were performed including 113 unique pathogen–antimicrobial combinations. A wide range of concentrations (0.25–8192 mg/L for colistin and 1–8192 mg/L for fusidic acid) were explored, alone and in combination. PKPD modelling sought to quantify synergistic effects. Results A PKPD model confirmed synergy in that colistin EC50 was found to decrease by 83% in the presence of fusidic acid, and fusidic acid maximum increase in killing rate (Emax) also increased 58% in the presence of colistin. Simulations indicated, however, that at clinically achievable free concentrations, the combination may be bacteriostatic in colistin-susceptible strains, but growth inhibition probability was <20% in a colistin-resistant strain. Conclusions Fusidic acid may be a useful agent to add to colistin in a multidrug combination for MDR Acinetobacter baumannii.
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Affiliation(s)
- Lynette M Phee
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London, UK.,Royal Free London NHS Foundation Trust, London, UK
| | - Frank Kloprogge
- Great Ormond Street Institute of Child Health, University College London, London, UK.,UCL Institute for Global Health, University College London, London, UK
| | - Rebecca Morris
- Medicines Research Centre, GlaxoSmithKline, Stevenage, UK
| | - John Barrett
- Medicines Research Centre, GlaxoSmithKline, Stevenage, UK
| | - David W Wareham
- Centre for Immunobiology, Blizard Institute, Queen Mary University of London, London, UK.,Barts Health NHS Trust, London, UK
| | - Joseph F Standing
- Great Ormond Street Institute of Child Health, University College London, London, UK.,Great Ormond Street Hospital for Children NHS Trust, London, UK
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