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Li H, E W, Zhao D, Liu H, Pei J, Du B, Liu K, Zhu X, Wang C. Response of Paenibacillus polymyxa SC2 to the stress of polymyxin B and a key ABC transporter YwjA involved. Appl Microbiol Biotechnol 2024; 108:17. [PMID: 38170316 DOI: 10.1007/s00253-023-12916-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/24/2023] [Accepted: 10/04/2023] [Indexed: 01/05/2024]
Abstract
Polymyxins are cationic peptide antibiotics and regarded as the "final line of defense" against multidrug-resistant bacterial infections. Meanwhile, some polymyxin-resistant strains and the corresponding resistance mechanisms have also been reported. However, the response of the polymyxin-producing strain Paenibacillus polymyxa to polymyxin stress remains unclear. The purpose of this study was to investigate the stress response of gram-positive P. polymyxa SC2 to polymyxin B and to identify functional genes involved in the stress response process. Polymyxin B treatment upregulated the expression of genes related to basal metabolism, transcriptional regulation, transport, and flagella formation and increased intracellular ROS levels, flagellar motility, and biofilm formation in P. polymyxa SC2. Adding magnesium, calcium, and iron alleviated the stress of polymyxin B on P. polymyxa SC2, furthermore, magnesium and calcium could improve the resistance of P. polymyxa SC2 to polymyxin B by promoting biofilm formation. Meanwhile, functional identification of differentially expressed genes indicated that an ABC superfamily transporter YwjA was involved in the stress response to polymyxin B of P. polymyxa SC2. This study provides an important reference for improving the resistance of P. polymyxa to polymyxins and increasing the yield of polymyxins. KEY POINTS: • Phenotypic responses of P. polymyxa to polymyxin B was performed and indicated by RNA-seq • Forming biofilm was a key strategy of P. polymyxa to alleviate polymyxin stress • ABC transporter YwjA was involved in the stress resistance of P. polymyxa to polymyxin B.
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Affiliation(s)
- Hui Li
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Wenhui E
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Dongying Zhao
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Haiyang Liu
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Jian Pei
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Binghai Du
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Kai Liu
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China
| | - Xueming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China
| | - Chengqiang Wang
- College of Life Sciences, National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, Shandong Engineering Research Center of Plant-Microbia Restoration for Saline-Alkali Land, Shandong Key Laboratory of Agricultural Microbiology, Shandong Agricultural University, Tai'an, 271018, China.
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Kon H, Hameir A, Nutman A, Temkin E, Keren Paz A, Lellouche J, Schwartz D, Weiss DS, Kaye KS, Daikos GL, Skiada A, Durante-Mangoni E, Dishon Benattar Y, Yahav D, Daitch V, Bernardo M, Iossa D, Friberg LE, Theuretzbacher U, Leibovici L, Dickstein Y, Pollak D, Mendelsohn S, Paul M, Carmeli Y. Prevalence and Clinical Consequences of Colistin Heteroresistance and Evolution into Full Resistance in Carbapenem-Resistant Acinetobacter baumannii. Microbiol Spectr 2023; 11:e0509322. [PMID: 37219426 PMCID: PMC10269815 DOI: 10.1128/spectrum.05093-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 05/08/2023] [Indexed: 05/24/2023] Open
Abstract
Colistin heteroresistance (HR) refers to a bacterial population comprised of several subpopulations with different levels of resistance to colistin. In this study, we discuss the classic form of HR, in which a resistant subpopulation exists within a predominantly susceptible population. We investigated the prevalence of colistin HR and its evolution into full resistance among 173 clinical carbapenem-resistant Acinetobacter baumannii isolates and examined the effect of HR on clinical outcomes. To determine HR, we performed population analysis profiling. Our results showed a high prevalence of HR (67.1%). To examine evolution of HR strains into full resistance, the HR strains were grown in colistin-containing broth, transferred onto colistin-containing plates, and colonies on these plates were transferred into colistin-free broth. Many of the HR strains (80.2%) evolved into full resistance, 17.2% reverted to HR, and 2.6% were borderline. We used logistic regression to compare 14-day clinical failure and 14-day mortality between patients infected by HR versus susceptible non-HR carbapenem-resistant A. baumannii. In the subgroup of patients with bacteremia, HR was significantly associated with 14-day mortality. IMPORTANCE To our knowledge, this is the first large-scale study to report on HR in Gram-negative bacteria. We described the prevalence of colistin HR in a large sample of carbapenem-resistant A. baumannii isolates, the evolution of many colistin HR isolates to a resistant phenotype following colistin exposure and withdrawal, and the clinical consequences of colistin HR. We found a high prevalence of HR among clinical carbapenem-resistant A. baumannii isolates; most evolved into a resistant phenotype following colistin exposure and withdrawal. In patients treated with colistin, evolution of HR A. baumannii into full resistance could lead to higher rates of treatment failure and contribute to the reservoir of colistin-resistant pathogens in health care settings.
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Affiliation(s)
- Hadas Kon
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Amichay Hameir
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Amir Nutman
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elizabeth Temkin
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Alona Keren Paz
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - Jonathan Lellouche
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
- Adelson School of Medicine, Ariel University, Israel
| | - David Schwartz
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
| | - David S. Weiss
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Keith S. Kaye
- Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
| | - George L. Daikos
- First Department of Medicine, Laikon General Hospital, Athens, Greece
- National and Kapodistrian University of Athens, Athens, Greece
| | - Anna Skiada
- First Department of Medicine, Laikon General Hospital, Athens, Greece
- National and Kapodistrian University of Athens, Athens, Greece
| | - Emanuele Durante-Mangoni
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
- AORN dei Colli-Monaldi Hospital, Naples, Italy
| | - Yael Dishon Benattar
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel
- Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Dafna Yahav
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Infectious Diseases Unit, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Vered Daitch
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Medicine E, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Mariano Bernardo
- Microbiology and Virology Unit, AORN Ospedali dei Colli-Monaldi Hospital, Naples, Italy
| | - Domenico Iossa
- Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | | | | | - Leonard Leibovici
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Medicine E, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Yaakov Dickstein
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel
| | - Dina Pollak
- Microbiology Laboratory, Rambam Health Care Campus, Haifa, Israel
| | - Sigal Mendelsohn
- Microbiology Laboratory, Rambam Health Care Campus, Haifa, Israel
| | - Mical Paul
- Institute of Infectious Diseases, Rambam Health Care Campus, Haifa, Israel
| | - Yehuda Carmeli
- National Institute for Antibiotic Resistance and Infection Control, Israel Ministry of Health, Tel Aviv, Israel
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Karpuz M, Temel A, Ozgenc E, Tekintas Y, Erel-Akbaba G, Senyigit Z, Atlihan-Gundogdu E. 99mTc-Labeled, Colistin Encapsulated, Theranostic Liposomes for Pseudomonas aeruginosa Infection. AAPS PharmSciTech 2023; 24:77. [PMID: 36899198 DOI: 10.1208/s12249-023-02533-8] [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: 10/20/2022] [Accepted: 02/12/2023] [Indexed: 03/12/2023] Open
Abstract
Infectious diseases are still the major issue not only due to antibiotic resistance but also causing deaths if not diagnosed at early-stages. Different approaches including nanosized drug delivery systems and theranostics are researched to overcome antibiotic resistance, decrease the side effects of antibiotics, improve the treatment response, and early diagnose. Therefore, in the present study, nanosized, radiolabeled with 99mTc, colistin encapsulated, neutral and cationic liposome formulations were prepared as the theranostic agent for Pseudomonas aeruginosa infections. Liposomes exhibited appropriate physicochemical properties thanks to their nano-particle size (between 173 and 217 nm), neutral zeta potential value (about - 6.5 and 2.8 mV), as well as encapsulation efficiency of about 75%. All liposome formulations were radiolabeled with over 90% efficiency, and the concentration of stannous chloride was found as 1 mg.mL-1 to obtain maximum radiolabeling efficiency. In alamar blue analysis, neutral liposome formulations were found more biocompatible compared with the cationic formulations. Neutral colistin encapsulated liposomes were found to be more effective against P. aeruginosa strain according to their time-dependent antibacterial effect, in addition to their highest bacterial binding capacity. As conclusion, theranostic, nanosized, colistin encapsulated, neutral liposome formulations were found as promising agents for the imaging and treating of P. aeruginosa infections.
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Affiliation(s)
- Merve Karpuz
- Department of Radiopharmacy, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Turkey.
| | - Aybala Temel
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Turkey
| | - Emre Ozgenc
- Department of Radiopharmacy, Faculty of Pharmacy, Ege University, Izmir, Turkey
| | - Yamac Tekintas
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Turkey
| | - Gulsah Erel-Akbaba
- Department of Pharmaceutical Biotechnology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Turkey
| | - Zeynep Senyigit
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Izmir Katip Celebi University, Izmir, Turkey
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Chen Z. Mechanisms and Clinical Relevance of Pseudomonas aeruginosa Heteroresistance. Surg Infect (Larchmt) 2023; 24:27-38. [PMID: 36622941 DOI: 10.1089/sur.2022.349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Abstract Background: Pseudomonas aeruginosa is an opportunistic pathogen that can cause various life-threatening infections. Several unique characteristics make it the ability of survivability and adaptable and develop resistance to antimicrobial agents through multiple mechanisms. Heteroresistance, which is a subpopulation-mediated resistance, has received increasing attention in recent years. Heteroresistance may lead to unexpected treatment failure if not diagnosed in time and treated properly. Therefore, heteroresistant Pseudomonas aeruginosa infections pose considerable problems for hospital-acquired infections. However, the clinical prevalence and implications of Pseudomonas aeruginosa heteroresistance have not been reviewed. Results: In this work, the aspects of the clinically reported heteroresistance of Pseudomonas aeruginosa to commonly used antibiotic agents are reviewed. The prevalence, mechanisms, and clinical relevance of each reported heteroresistant Pseudomonas aeruginosa are discussed.
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Affiliation(s)
- Zhao Chen
- College of Pharmaceutical Science, Collaborative Innovation Center of Yangtza River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, P.R. China
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Effectiveness and Nephrotoxicity of Loading Dose Colistin-Meropenem versus Loading Dose Colistin-Imipenem in the Treatment of Carbapenem-Resistant Acinetobacter baumannii Infection. Pharmaceutics 2022; 14:pharmaceutics14061266. [PMID: 35745838 PMCID: PMC9228626 DOI: 10.3390/pharmaceutics14061266] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 06/12/2022] [Accepted: 06/13/2022] [Indexed: 12/04/2022] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) is becoming more widely recognized as a serious cause of nosocomial infections, and colistin has been reintroduced in recent years for the treatment of CRAB infection. Combinations of colistin and meropenem or imipenem have been found to be effective against CRAB isolates, whereas clinical investigations have not definitively demonstrated the theoretical benefits of colistin combined therapy in patients with CRAB infections. The objective of this study was to compare the primary outcome (30-day survival rate) and secondary outcomes (clinical response, microbiological response and nephrotoxicity) between patients who received loading dose (LD) colistin−meropenem and LD colistin−imipenem for the treatment of CRAB infection. A retrospective cohort analysis was performed at Chiang Mai University Hospital in patients with CRAB infection who received LD colistin−meropenem or LD colistin−imipenem between 2011 and 2017, and 379 patients fulfilled the requirements for the inclusion criteria. The results of this study showed that patients who received LD colistin−imipenem had a lower 30-day survival rate (adjusted HR = 0.57, 95% CI: 0.37−0.90; p = 0.015) and a lower clinical response (aHR = 0.56, 95% CI: 0.35−0.90; p = 0.017) compared with those who received LD colistin−meropenem. The microbiological response in patients with LD colistin−imipenem was 0.52 times (aHR) lower than that in those who received colistin−meropenem (95% CI: 0.34−0.81; p = 0.004); however, there was no significant difference in nephrotoxicity (aHR = 1.03, 95% CI: 0.67−1.57; p = 0.897) between the two combination regimens. In conclusion, when comparing the combination of LD colistin with imipenem or meropenem, the combination of LD colistin and meropenem provides a better survival rate for treating CRAB. Thus, we suggest that combinations of LD colistin and meropenem should be considered when treating CRAB infections.
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Efficacy of Combination Therapies for the Treatment of Multi-Drug Resistant Gram-Negative Bacterial Infections Based on Meta-Analyses. Antibiotics (Basel) 2022; 11:antibiotics11040524. [PMID: 35453274 PMCID: PMC9027966 DOI: 10.3390/antibiotics11040524] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/08/2022] [Accepted: 04/12/2022] [Indexed: 02/05/2023] Open
Abstract
There is increasing evidence regarding the optimal therapeutic strategies for multidrug-resistant (MDR) bacteria that cause common infections and are resistant to existing antibiotics. Combination therapies, such as β-lactam combined with β-lactamase inhibitors or combination antibiotics, is a therapeutic strategy to overcome MDR bacteria. In recent years, the therapeutic options have expanded as certain combination drugs have been approved in more countries. However, only a handful of guidelines support these options, and the recommendations are based on low-quality evidence. This review describes the significance and efficacy of combination therapy as a therapeutic strategy against Gram-negative MDR pathogens based on previously reported meta-analyses.
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Singh R, Capalash N, Sharma P. Vaccine development to control the rising scourge of antibiotic-resistant Acinetobacter baumannii: a systematic review. 3 Biotech 2022; 12:85. [PMID: 35261870 PMCID: PMC8890014 DOI: 10.1007/s13205-022-03148-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 02/11/2022] [Indexed: 03/02/2023] Open
Abstract
Acinetobacter baumannii has emerged as one of major nosocomial pathogen and global emergence of multidrug-resistant strains has become a challenge for developing effective treatment options. A. baumannii has developed resistance to almost all the antibiotics viz. beta-lactams, carbapenems, tigecycline and now colistin, a last resort of antibiotics. The world is on the cusp of post antibiotic era and the evolution of multi-, extreme- and pan–drug-resistant A. baumannii strains is its obvious harbinger. Various combinations of antibiotics have been investigated but no successful treatment option is available. All these failed efforts have led researchers to develop and implement prophylactic vaccination for the prevention of infections caused by this pathogen. In this review, the advantages and disadvantages of active and passive immunization, the types of sub-unit and multi-component vaccine candidates investigated against A. baumannii viz. whole cell organism, outer membrane vesicles, outer membrane complexes, conjugate vaccines and sub-unit vaccines have been discussed. In addition, the benefits of Reverse vaccinology are emphasized here in which the potential vaccine candidates are predicted using bioinformatic online tools prior to in vivo validations.
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The Role of Colistin in the Era of New β-Lactam/β-Lactamase Inhibitor Combinations. Antibiotics (Basel) 2022; 11:antibiotics11020277. [PMID: 35203879 PMCID: PMC8868358 DOI: 10.3390/antibiotics11020277] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/17/2022] [Accepted: 02/17/2022] [Indexed: 02/06/2023] Open
Abstract
With the current crisis related to the emergence of carbapenem-resistant Gram-negative bacteria (CR-GNB), classical treatment approaches with so-called “old-fashion antibiotics” are generally unsatisfactory. Newly approved β-lactam/β-lactamase inhibitors (BLBLIs) should be considered as the first-line treatment options for carbapenem-resistant Enterobacterales (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) infections. However, colistin can be prescribed for uncomplicated lower urinary tract infections caused by CR-GNB by relying on its pharmacokinetic and pharmacodynamic properties. Similarly, colistin can still be regarded as an alternative therapy for infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) until new and effective agents are approved. Using colistin in combination regimens (i.e., including at least two in vitro active agents) can be considered in CRAB infections, and CRE infections with high risk of mortality. In conclusion, new BLBLIs have largely replaced colistin for the treatment of CR-GNB infections. Nevertheless, colistin may be needed for the treatment of CRAB infections and in the setting where the new BLBLIs are currently unavailable. In addition, with the advent of rapid diagnostic methods and novel antimicrobials, the application of personalized medicine has gained significant importance in the treatment of CRE infections.
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Bacterial heteroresistance: an evolving novel way to combat antibiotics. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00820-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
In this study, we investigated the colistin heteroresistance patterns in Acinetobacter baumannii isolates. To identify colistin heteroresistance, population analysis profiling was performed for six in vitro colistin-susceptible A. baumannii isolates. Survival rates with and without prior exposure to colistin (at concentrations between 0 and 32 mg/L) were measured in media with and without colistin. Amino acid substitutions were also detected in colonies that survived in media with 4 mg/L colistin without further antibiotic treatment in six A. baumannii isolates. A stability test was also performed to investigate whether colistin resistance is maintained without antibiotic treatment. Although only three isolates showed typical colistin heteroresistance pattern, colistin-resistant populations were identified even without prior exposure to colistin in all A. baumannii isolates. Nearly all colonies of typical colistin-heteroresistant isolates (Type I heteroresistance) that survived after exposure to high colistin concentrations were found to be colistin-resistant, whereas no resistant colonies were identified in the other isolates (Type II heteroresistance). Stability tests showed that most of the surviving populations in media with 4 mg/L colistin without further antibiotic exposure failed to preserve resistance to colistin. Colistin-resistant populations also showed either no change in amino acid sequences, or diverse amino acid substitutions. We identified two types of colistin heteroresistance in A. baumannii isolates. Because Type I colistin-heteroresistant A. baumannii isolates could not be eradicated in vitro by high concentrations of colistin, differentiating two colistin heteroresistance types would be important for the treatment of A. baumannii infections using colistin.
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Affiliation(s)
- Yoon-Kyoung Hong
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Hyunkeun Kim
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kwan Soo Ko
- Department of Microbiology and Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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The highly dynamic nature of bacterial heteroresistance impairs its clinical detection. Commun Biol 2021; 4:521. [PMID: 33953333 PMCID: PMC8099907 DOI: 10.1038/s42003-021-02052-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/26/2021] [Indexed: 11/23/2022] Open
Abstract
Many bacterial species and antibiotic classes exhibit heteroresistance, a phenomenon in which a susceptible bacterial isolate harbors a resistant subpopulation that can grow in the presence of an antibiotic and cause treatment failure. The resistant phenotype is often unstable and without antibiotic selection it reverts back to susceptibility. Here we studied the dynamics by which these resistant subpopulations are enriched in the presence of antibiotic and recede back to their baseline frequency in the absence of selection. An increasing understanding of this instability will allow more effective diagnostics and treatment of infections caused by heteroresistant bacteria. We show for clinical isolates of Escherichia coli and Salmonella enterica that different antibiotics at levels below the MIC of the susceptible main population can cause rapid enrichment of resistant subpopulations with increased copy number of genes that cause resistance. Modelling and growth rate measurements of bacteria with increased gene copy number in cultures and by microscopy of single-cells in a microfluidic chip show that the fitness cost of gene amplifications and their intrinsic instability drives their rapid loss in the absence of selection. Using a common antibiotic susceptibility test, we demonstrate that this test strongly underestimates the occurrence of heteroresistance in clinical isolates. Bacterial populations can show heteroresistance, where an antibiotic resistant subpopulation is part of a susceptible one. Pereira et al. show in Escherichia coli and Salmonella enterica that disk diffusion, a common antibiotic susceptibility test, underestimates the occurrence of heteroresistance in clinical isolates.
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Abstract
Antibiotic resistance is a major global health challenge and, worryingly, several key Gram negative pathogens can become resistant to most currently available antibiotics. Polymyxins have been revived as a last-line therapeutic option for the treatment of infections caused by multidrug-resistant Gram negative bacteria, in particular Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales. Polymyxins were first discovered in the late 1940s but were abandoned soon after their approval in the late 1950s as a result of toxicities (e.g., nephrotoxicity) and the availability of "safer" antibiotics approved at that time. Therefore, knowledge on polymyxins had been scarce until recently, when enormous efforts have been made by several research teams around the world to elucidate the chemical, microbiological, pharmacokinetic/pharmacodynamic, and toxicological properties of polymyxins. One of the major achievements is the development of the first scientifically based dosage regimens for colistin that are crucial to ensure its safe and effective use in patients. Although the guideline has not been developed for polymyxin B, a large clinical trial is currently being conducted to optimize its clinical use. Importantly, several novel, safer polymyxin-like lipopeptides are developed to overcome the nephrotoxicity, poor efficacy against pulmonary infections, and narrow therapeutic windows of the currently used polymyxin B and colistin. This review discusses the latest achievements on polymyxins and highlights the major challenges ahead in optimizing their clinical use and discovering new-generation polymyxins. To save lives from the deadly infections caused by Gram negative "superbugs," every effort must be made to improve the clinical utility of the last-line polymyxins. SIGNIFICANCE STATEMENT: Antimicrobial resistance poses a significant threat to global health. The increasing prevalence of multidrug-resistant (MDR) bacterial infections has been highlighted by leading global health organizations and authorities. Polymyxins are a last-line defense against difficult-to-treat MDR Gram negative pathogens. Unfortunately, the pharmacological information on polymyxins was very limited until recently. This review provides a comprehensive overview on the major achievements and challenges in polymyxin pharmacology and clinical use and how the recent findings have been employed to improve clinical practice worldwide.
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Affiliation(s)
- Sue C Nang
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Mohammad A K Azad
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Tony Velkov
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Qi Tony Zhou
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Melbourne, Victoria, Australia (S.C.N., M.A.K.A., J.L.); Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia (T.V.); and Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana (Q.T.Z.)
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Kagami K, Ishiguro N, Yamada T, Niinuma Y, Iwasaki S, Taki K, Fukumoto T, Hayasaka K, Oyamada R, Watanabe T, Nishida M, Sugita J, Teshima T, Sugawara M, Takekuma Y. Efficacy and safety of colistin for the treatment of infections caused by multidrug-resistant gram-negative bacilli. J Infect Chemother 2020; 27:473-479. [PMID: 33144146 DOI: 10.1016/j.jiac.2020.10.024] [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: 08/13/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND The efficacy and safety of colistin for the treatment of infections caused by multidrug-resistant gram-negative bacilli have been poorly investigated in Japanese patients. This study was performed to investigate the efficacy and safety of colistin in Japanese patients by analyzing a considerable number of cases. Furthermore, we evaluated the relationship between the plasma concentration and efficacy and safety of colistin in some cases. METHODS A retrospective cohort study was conducted at Hokkaido University Hospital, analyzing patients treated with colistin (colistimethate sodium) during the period from January 2007 to December 2019. RESULTS Overall, 42 cases were enrolled. Favorable clinical response was observed in 25 cases (59.5%), with an all-cause 30-day mortality of 33.3% (14/42 cases). Microbiological eradication was achieved in 18 cases (42.9%). Nephrotoxicity was observed in 20 cases (47.6%) and was mild and reversible in all cases. Plasma trough concentrations of colistin determined in nine patients correlated with changes in serum creatinine concentration (⊿) and creatinine clearance (%). The cutoff value of colistin trough concentration for nephrotoxicity was 2.02 μg/mL. CONCLUSION Our results showed approximately 60% clinical efficacy of colistin therapy against infections caused by multidrug-resistant gram-negative bacilli in the patients. Further studies with larger populations are needed to elucidate the efficacy and safety of colistin in Japanese patients.
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Affiliation(s)
- Keisuke Kagami
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Nobuhisa Ishiguro
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Takehiro Yamada
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Yusuke Niinuma
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Sumio Iwasaki
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Keisuke Taki
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Tatsuya Fukumoto
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Kasumi Hayasaka
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Reiko Oyamada
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Tsubasa Watanabe
- Department of Infection Control and Prevention, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Mutsumi Nishida
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan
| | - Junichi Sugita
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Department of Hematology, Faculty of Medicine, Hokkaido University, Kita-15-jo, Nishi-7-chome, Kita-ku, Sapporo 060-8638, Japan
| | - Takanori Teshima
- Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Department of Hematology, Faculty of Medicine, Hokkaido University, Kita-15-jo, Nishi-7-chome, Kita-ku, Sapporo 060-8638, Japan
| | - Mitsuru Sugawara
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan; Laboratory of Pharmacokinetics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo 060-0812, Japan
| | - Yoh Takekuma
- Department of Pharmacy, Hokkaido University Hospital, Kita-14-jo, Nishi-5-chome, Kita-ku, Sapporo 060-8648, Japan.
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14
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Hou SY, Wu D, Feng XH. Polymyxin monotherapy versus polymyxin-based combination therapy against carbapenem-resistant Klebsiella pneumoniae: A systematic review and meta-analysis. J Glob Antimicrob Resist 2020; 23:197-202. [PMID: 33091620 DOI: 10.1016/j.jgar.2020.08.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/21/2020] [Accepted: 08/31/2020] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES This meta-analysis was performed to compare polymyxin monotherapy and polymyxin-based combination therapy for carbapenem-resistant Klebsiella pneumoniae (CR-KP) infections. METHODS We conducted searches on MEDLINE, Embase and Cochrane Collaborative database for both observational studies and randomised controlled trials (RCTs) comparing polymyxin monotherapy with polymyxin-based combination therapy in patients with CR-KP infection. The primary outcome was mortality. We divided all included studies into several groups according to different combination-combination and different infection types. The odds ratio (OR) and 95% confidence intervals (CI) were calculated for outcome analysis. RESULTS Ten studies with 481 patients were included. Polymyxin monotherapy was associated with higher mortality than polymyxin-based combination therapy in treatment of CR-KP bloodstream infections (BSI) (OR 1.93, 95% CI 1.14-3.27, P = 0.01) and ventilator-associated pneumonia (VAP)/hospital-acquired pneumonia (HAP) (OR 3.82, 95% CI 1.15-12.71, P = 0.03). In subgroup analysis of different combinations, mortality was significantly higher with polymyxin monotherapy compared with combination therapy with tigecycline (OR 1.88, 95% CI 1.05-3.37, P = 0.03), or with cabapenem (OR 3.11, 95% CI 1.25-7.74, P = 0.01), but no differences were found in combinations with aminoglycosides (OR 1.29, 95% CI 0.72-2.29, P = 0.38). Three-drug combination therapy including polymyxin was also associated with significant survival benefit (OR 3.86, 95% CI 1.60-9.32, P = 0.003). CONCLUSIONS Polymyxin-based combination therapy provides significant survival benefit in treatment of CR-KP, which appears to be more pronounced when a carbapenem or tigecycline is included in the regimen.
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Affiliation(s)
- Si-Yuan Hou
- Intensive Care Unit, The People's Hospital of Liaoning Province, NO. 33 Wenyi Road, Shenhe District, Shenyang, Liaoning 110016, China.
| | - Dan Wu
- Second Department of Rheumatology, Shengjing Hospital of China Medical University, 39 Huaxiang Road, Tiexi District, Shenyang, Liaoning 110022, China.
| | - Xing-Huo Feng
- Intensive Care Unit, The People's Hospital of Liaoning Province, NO. 33 Wenyi Road, Shenhe District, Shenyang, Liaoning 110016, China.
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15
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Ma XL, Guo YZ, Wu YM, Gong WT, Sun J, Huang Z. In vivo bactericidal effect of colistin-linezolid combination in a murine model of MDR and XDR Acinetobacter baumannii pneumonia. Sci Rep 2020; 10:17518. [PMID: 33060737 PMCID: PMC7567802 DOI: 10.1038/s41598-020-74503-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/01/2020] [Indexed: 11/09/2022] Open
Abstract
Recently, paradoxical combinations of colistin with anti-Gram-positive bacterial agents were introduced as a treatment alternative for multidrug-resistant Acinetobacter baumannii (MDRAB) infection. We assessed the therapeutic efficacy of the colistin–linezolid combination regimen in vitro and in a murine model of Acinetobacter baumannii pneumonia. A multidrug-resistant clinical strain (MDRAB31) and an extensively drug-resistant clinical strain (XDRAB78) were used in this study. The survival rates of mice and bacterial counts in lung tissue were used to assess the effects of colistin–linezolid combination. The survival rates of colistin–linezolid combination groups significantly increased compared with colistin groups for MDRAB31 (72% versus 32%, P = 0.03) and for XDRAB78 (92% versus 68%, P = 0.031). The colistin–linezolid combination groups significantly reduced the bacterial counts in lung tissue compared with colistin groups for MDRAB31 and for XDRAB78 (P < 0.05). The colistin–linezolid combination had a bactericidal and synergistic effect compared with colistin alone in time-kill assay and in murine model of pneumonia. Our data demonstrated the synergistic effect of colistin–linezolid combination regimen as a treatment alternative for the severe pulmonary infection caused by MDRAB and XDRAB.
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Affiliation(s)
- Xiao-Lin Ma
- Department of Neurology, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China
| | - Yong-Zhong Guo
- Department of Respiratory and Critical Care Medicine, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China
| | - Yan-Min Wu
- Department of Respiratory and Critical Care Medicine, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China
| | - Wei-Tao Gong
- Department of Respiratory and Critical Care Medicine, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China.
| | - Jie Sun
- Department of Respiratory and Critical Care Medicine, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China
| | - Zhen Huang
- Department of Respiratory and Critical Care Medicine, XuZhou Central Hospital, The Xuzhou School of Clinical Medicine of Nanjing Medical University, XuZhou Clinical School of Xuzhou Medical University, Xuzhou, 221009, Jiangsu, China
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16
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Huang L, Feng Y, Zong Z. Heterogeneous resistance to colistin in Enterobacter cloacae complex due to a new small transmembrane protein. J Antimicrob Chemother 2020; 74:2551-2558. [PMID: 31169899 DOI: 10.1093/jac/dkz236] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 04/28/2019] [Accepted: 05/05/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Enterobacter strains can display heterogeneous resistance (heteroresistance) to colistin but the mechanisms remain largely unknown. We investigated potential mechanisms of colistin heteroresistance in an Enterobacter clinical strain, WCHECl-1060, and found a new mechanism. METHODS Strain WCHECl-1060 was subjected to WGS to identify known colistin resistance mechanisms. Tn5 insertional mutagenesis, gene knockout and complementation and shotgun cloning were employed to investigate unknown colistin heteroresistance mechanisms. RNA sequencing was performed to link the newly identified mechanism with known ones. RESULTS We showed that the phoP gene [encoding part of the PhoP-PhoQ two-component system (TCS)], the dedA(Ecl) gene (encoding an inner membrane protein of the DedA family) and the tolC gene (encoding part of the AcrAB-TolC efflux pump) are required for colistin heteroresistance. We identified a new gene, ecr, encoding a 72 amino acid transmembrane protein, which was able to mediate colistin heteroresistance. We then performed RNA sequencing and transcriptome analysis and found that in the presence of ecr the expression of phoP and the arnBCADTEF operon, which synthesizes and transfers l-Ara4N to lipid A, was increased significantly. CONCLUSIONS The small protein encoded by ecr represents a new colistin heteroresistance mechanism and is likely to mediate colistin heteroresistance via the PhoP-PhoQ TCS to act on the arnBCADTEF operon.
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Affiliation(s)
- Liang Huang
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Public Health Clinical Center of Chengdu, Chengdu, China
| | - Yu Feng
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China
| | - Zhiyong Zong
- Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China.,Division of Infectious Diseases, State Key Laboratory of Biotherapy, Chengdu, China.,Department of Infection Control, West China Hospital, Sichuan University, Chengdu, China
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17
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Karakonstantis S, Saridakis I. Colistin heteroresistance in Acinetobacter spp.: systematic review and meta-analysis of the prevalence and discussion of the mechanisms and potential therapeutic implications. Int J Antimicrob Agents 2020; 56:106065. [PMID: 32599229 DOI: 10.1016/j.ijantimicag.2020.106065] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/30/2020] [Accepted: 06/20/2020] [Indexed: 01/29/2023]
Abstract
BACKGROUND Colistin is one of the few remaining options for carbapenem-resistant Acinetobacter baumannii (A. baumannii); however, emergence of resistance from heteroresistant populations is possible. This review aimed to systematically search and consolidate the literature on the prevalence, mechanisms and therapeutic implications of colistin heteroresistance in Acinetobacter spp. METHODS A systematic search was conducted in PubMed and Scopus. The pooled prevalence of colistin heteroresistance was calculated using meta-analysis of proportions with the Freeman-Tukey transformation and the random-effects (DerSimonian and Laird) method. RESULTS Based on 15 studies the prevalence of colistin heteroresistance was 33% (95% CI 16-53%) but considerable heterogeneity was observed (I2 = 96%, P < 0.001). Prior exposure to colistin was associated with a higher proportion of resistant subpopulations. Colistin heteroresistance may result from chromosomal mutations in resistant subpopulations (predominantly in PmrAB and lpx genes) resulting in lipopolysaccharide modification or loss, or overexpression of efflux pumps. No dosage scheme of colistin monotherapy can prevent the emergence of resistant subpopulations in vitro, but few studies have reported in vivo emergence of resistance from heteroresistant A. baumannii during treatment, and studies examining the correlation between heteroresistance and clinical/microbiological outcomes are lacking. Several colistin-based combinations have been shown in vitro to prevent the emergence of the resistant subpopulations but none have been translated so far into clinical benefit. Reasons for this discrepancy are discussed. CONCLUSIONS Colistin heteroresistance was common but highly variable between studies. The impact of colistin heteroresistance (frequency of emergent resistance during treatment and correlation with treatment outcomes) requires further study.
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Affiliation(s)
- Stamatis Karakonstantis
- School of Medicine, University of Crete, Heraklion, Crete, Greece; Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece.
| | - Ioannis Saridakis
- Internal Medicine Department, General Hospital of Heraklion Venizeleio, Heraklion, Crete, Greece
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18
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Çağlan E, Nigiz Ş, Sancak B, Gür D. Resistance and heteroresistance to colistin among clinical isolates of Acinetobacter baumannii. Acta Microbiol Immunol Hung 2020; 67:107-111. [PMID: 31813259 DOI: 10.1556/030.66.2019.021] [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] [Received: 08/05/2019] [Accepted: 08/13/2019] [Indexed: 01/05/2023]
Abstract
Colistin is one of the most effective alternatives for treating Acinetobacter baumannii infections. The aim of this study was to determine colistin resistance and heteroresistance rates in A. baumannii from clinical samples in Hacettepe University clinical microbiology laboratory between June 2016 and January 2017. A total of 200 isolates were included in the study. In vitro susceptibility to amikacin, gentamicin, ceftazidime, piperacillin/tazobactam, meropenem, ciprofloxacin, and tigecycline were determined by disk diffusion test. Most isolates were multiresistant as they exhibited resistance to aminoglycosides, β-lactams, and fluoroquinolones. Colistin susceptibility was determined by broth microdilution (BMD) test (EUCAST standards) and was compared with E-test (bioMérieux, France) in 120 isolates. In 14 blood isolates that were susceptible to colistin (MIC ≤ 2 mg/L), heteroresistance was investigated with the population analysis profile (PAP) method. Overall resistance (n = 200) to colistin was 28% by BMD. Among the 120 isolates where the two tests were compared, resistance to colistin was 25.8% versus 4.2% with BMD and E-test, respectively. Three blood isolates (21.4%) were heteroresistant to colistin. With E-test, a majority of the resistant isolates are overlooked and in vitro susceptibility to colistin should be determined with broth dilution method. This is the first study in Turkey reporting heteroresistance in A. baumannii isolates by the PAP method and emphasizes the need to test for heteroresistance in relation to clinical outcome in serious infections due to A. baumannii.
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Affiliation(s)
- Ecem Çağlan
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Şeyma Nigiz
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Banu Sancak
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Deniz Gür
- Department of Medical Microbiology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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19
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Acquisition of Colistin Resistance Links Cell Membrane Thickness Alteration with a Point Mutation in the lpxD Gene in Acinetobacter baumannii. Antibiotics (Basel) 2020; 9:antibiotics9040164. [PMID: 32268563 PMCID: PMC7235794 DOI: 10.3390/antibiotics9040164] [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: 03/10/2020] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 02/04/2023] Open
Abstract
Acinetobacter baumannii is one of the most common causes of nosocomial infections in intensive care units. Its ability to acquire diverse mechanisms of resistance limits the therapeutic choices for its treatment. This especially concerns colistin, which has been reused recently as a last-resort drug against A. baumannii. Here, we explored the impact of gaining colistin resistance on the susceptibility of A. baumannii to other antibiotics and linked colistin resistance acquisition to a gene mutation in A. baumannii. The susceptibility of 95 A. baumannii isolates revealed that 89 isolates were multi-drug resistance (MDR), and nine isolates were resistant to colistin. Subsequently, three isolates, i.e., MS48, MS50, and MS64, exhibited different resistance patterns when colistin resistance was induced and gained resistance to almost all tested antibiotics. Upon TEM examination, morphological alterations were reported for all induced isolates and a colistin-resistant clinical isolate (MS34Col-R) compared to the parental sensitive strains. Finally, genetic alterations in PmrB and LpxACD were assessed, and a point mutation in LpxD was identified in the MS64Col-R and MS34Col-R mutants, corresponding to Lys117Glu substitution in the lipid-binding domain. Our findings shed light on the implications of using colistin in the treatment of A. baumannii, especially at sub-minimum inhibitory concentrations concentrations, since cross-resistance to other classes of antibiotics may emerge, beside the rapid acquisition of resistance against colistin itself due to distinct genetic events.
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20
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Kamali M, Manshouri S, Bagheri Y, Rostami M, Karkhaneh Mahmoudi M, Moradnejad P, Seif F. Prevalence and antibiotic resistance of Acinetobacter baumannii among patients in postcardiac surgery intensive care units of Rajaei Hospital, Tehran. Med J Islam Repub Iran 2020; 34:4. [PMID: 32284928 PMCID: PMC7139260 DOI: 10.34171/mjiri.34.4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Indexed: 12/30/2022] Open
Abstract
Background: Acinetobacter baumannii is an opportunistic, aerobic, nonfermentative, Gram-negative bacterium that can cause major nosocomial infections, especially in patients hospitalized in intensive care units (ICU). Recently, A. baumannii strains have been resistant to a variety of antibiotics. Thus, it was aimed to evaluate the prevalence of A. baumannii and their resistance to the antibiotics in the patients hospitalized in postcardiac surgery ICU. Methods: This retrospective cross sectional study was performed in Rajaei hospital between March 2014 and February 2016. A. baumannii strains were isolated from blood cultures, catheter cultures, sputum cultures, and wound smear cultures. Then, isolates were characterized using standard morphological, cultural, and biochemical properties according to CLSI 2016. The frequency of A. baumannii species were reported as percent. Results: Among 27 167 patients were admitted to the ICU, 113 individuals, including 55 males and 58 females, were identified as A. baumannii-infected and the prevalence rate was 0.42%. The highest rates of antibiotic sensitivity were related to Meropenem 20 (17.7%) and Colistin 16 (14.1%). The shortest length of stay (LOS) for patients with A. baumanniiin the ICU was 3 days, while the longest LOS was 98 days. Conclusion: The findings indicated that A. baumannii strains isolated from postcardiac surgery ICUs had a high prevalence and were sensitive to Meropenem and Colistin. However, new molecular-based techniques are needed to monitor nosocomial infections. Therefore, the treatment of the patients may be feasible by appropriate antibiotic therapy, and infection control policies will be improved by adopting precise disinfection strategies.
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Affiliation(s)
- Monireh Kamali
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shirin Manshouri
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Yasser Bagheri
- Immunology Research Center, Institute of Immunology and infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.,Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Rostami
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahdi Karkhaneh Mahmoudi
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Pardis Moradnejad
- Rajaei Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Farhad Seif
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran.,Academic Center for Education, Culture, and Research, Tehran, Iran
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21
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Vazquez Guillamet C, Kollef MH. Acinetobacter Pneumonia: Improving Outcomes With Early Identification and Appropriate Therapy. Clin Infect Dis 2019; 67:1455-1462. [PMID: 29741597 DOI: 10.1093/cid/ciy375] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/03/2018] [Indexed: 12/15/2022] Open
Abstract
In an era of increasing antimicrobial resistance, Acinetobacter distinguishes itself as one of the most resistant Gram-negative bacteria responsible for significant morbidity and mortality. New solutions are needed to combat the detrimental effects of increasing rates of antimicrobial resistance. Using empiric broad-spectrum antibiotics in patients deemed at risk for infections caused by multidrug-resistant pathogens may protect against attributable mortality, but this temporary solution furthers the risk of antimicrobial resistance. In this article we will review relevant strategies to aid with early identification and appropriate treatment of Acinetobacter pneumonia while preserving antibiotic susceptibility.
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Affiliation(s)
- Cristina Vazquez Guillamet
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of New Mexico School of Medicine, Albuquerque.,Division of Infectious Diseases, University of New Mexico School of Medicine, Albuquerque
| | - Marin H Kollef
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, Missouri
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22
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Wang Y, Li H, Xie X, Wu X, Li X, Zhao Z, Luo S, Wan Z, Liu J, Fu L, Li X. In vitro and in vivo assessment of the antibacterial activity of colistin alone and in combination with other antibiotics against Acinetobacter baumannii and Escherichia coli. J Glob Antimicrob Resist 2019; 20:351-359. [PMID: 31557565 DOI: 10.1016/j.jgar.2019.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 09/06/2019] [Accepted: 09/16/2019] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES Limited therapeutic options exist for treating severe infections caused by multidrug-resistant (MDR) and extensively drug-resistant Gram-negative bacteria (GNB). In this study, the activity of colistin (COL) as monotherapy and in combination with other antibiotics against Acinetobacter baumannii in vitro was investigated. In addition, the efficacy of intravenous colistimethate sodium (CMS) was evaluated in a murine model of urinary tract infection (UTI) induced by MDR Escherichia coli. METHODS Minimum inhibitory concentration (MIC), Monte Carlo simulation, fractional inhibitory concentration index (FICI), time-kill study and erythrocyte lysis assay were applied to evaluate the effect and cytotoxicity of COL, meropenem, imipenem, doripenem (DOR) and sulbactam alone and in combination. For the in vivo experiment, determination of the bacterial burden and histopathological examination were performed to evaluate the efficacy of CMS against UTI. RESULTS Of 106 A. baumannii isolates, 104 (98.1%) were susceptible to COL. In the chequerboard assay, COL + DOR showed the highest rate of synergism (60%). No antagonism or cytotoxicity was observed. All COL-based combinations were able to inhibit or slow bacterial re-growth in a time-kill assay. In an in vivo activity study, intravenous CMS reduced not only the bacterial load but also inflammation and maintained structural integrity of infected bladders and kidneys. CONCLUSION The effectiveness of COL alone in vitro and in vivo suggested that intravenous CMS will be an effective and available therapeutic strategy for UTI due to MDR-GNB. In-depth in vitro tests demonstrated that COL + DOR could be an attractive option, especially when the COL MIC is ≥1 μg/mL.
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Affiliation(s)
- Yale Wang
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - He Li
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China; Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450001, China
| | - Xiaoqian Xie
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - XiaoHan Wu
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Xinxin Li
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Zeyue Zhao
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Shasha Luo
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Zhijie Wan
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Jingjing Liu
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China
| | - Lei Fu
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China.
| | - Xiaotian Li
- School of Pharmaceutical Sciences, Zhengzhou University, 100 Kexue Avenue, Zhengzhou, Henan 450001, China.
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Lee W, Cai Y, Lim TP, Teo J, Chua SC, Kwa ALH. In vitro Pharmacodynamics and PK/PD in Animals. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:105-116. [PMID: 31364074 DOI: 10.1007/978-3-030-16373-0_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
In the last decade, considerable advancements have been made to identify the pharmacokinetic/pharmacodynamic (PK/PD) index that defines the antimicrobial activity of polymyxins. Dose-fractionation studies performed in hollow-fiber models found that altering the dosing schedule had little impact on the killing or suppression of resistance emergence, alluding to AUC/MIC as the pharmacodynamic index that best describes polymyxin's activity. For in vivo efficacy, the PK/PD index that was the most predictive of the antibacterial effect of colistin against P. aeruginosa and A. baumannii was ƒAUC/MIC.
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Affiliation(s)
- Winnie Lee
- Singapore General Hospital, Singapore, Singapore
| | - Yiying Cai
- Singapore General Hospital, Singapore, Singapore
| | - Tze-Peng Lim
- Singapore General Hospital, Singapore, Singapore
| | - Jocelyn Teo
- Singapore General Hospital, Singapore, Singapore
| | - Sonja Courtney Chua
- Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Andrea Lay-Hoon Kwa
- Singapore General Hospital, Singapore, Singapore. .,Department of Pharmacy, Faculty of Science, National University of Singapore, Singapore, Singapore. .,Emerging Infectious Diseases, Duke-National University of Singapore Medical School, Singapore, Singapore.
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Chai G, Park H, Yu S, Zhou F, Li J, Xu Q, Zhou QT. Evaluation of co-delivery of colistin and ciprofloxacin in liposomes using an in vitro human lung epithelial cell model. Int J Pharm 2019; 569:118616. [PMID: 31415873 DOI: 10.1016/j.ijpharm.2019.118616] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/07/2019] [Accepted: 08/12/2019] [Indexed: 01/15/2023]
Abstract
Respiratory tract infections caused by multidrug-resistant Gram-negative bacteria are serious burdens to the public. Our previous findings indicated that co-loading of colistin and ciprofloxacin via liposomes improved in vitro antimicrobial activities against multidrug resistant Pseudomonas aeruginosa as compared to the monotherapies. The current study aims to investigate the transport behavior of colistin and ciprofloxacin in liposomes using the in vitro Calu-3 cell monolayer, which is a lung epithelial model cultured under the air-interfaced condition. The cell viability results demonstrated that there was no obvious toxicity of cells exposed to single or co-administered drugs at the concentration ≤500 μg/mL. Transport of ciprofloxacin into the cells was easier than that of colistin, which reached a plateau rapidly. Colistin was less trapped in the mucus or adhered to the apical cell membrane, and less transported across the cell monolayer than ciprofloxacin. The deposition of ciprofloxacin on the apical side increased over time (from 1 to 4 h). There was no drug-drug interaction observed during the transport of ciprofloxacin and colistin across the cell monolayer, when they were dosed together in the solution form. The amount of drug transported across the cell monolayer was decreased in both agents when loaded in liposomes. Both drugs were more trapped in the mucus or more adhered to the apical side cell membrane of the cell monolayer when they were in liposomes. This study demonstrated that co-delivery of colistin and ciprofloxacin in a single liposome can reduce transport capacity of both drugs across the lung epithelial cell monolayer and enhance drug retention on the lung epithelial surfaces; therefore, it is a promising approach to treat the respiratory infections caused by multidrug resistant Pseudomonas aeruginosa.
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Affiliation(s)
- Guihong Chai
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Heejun Park
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Shihui Yu
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA
| | - Fanfan Zhou
- School of Pharmacy, The University of Sydney, NSW 2006, Australia
| | - Jian Li
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Qingguo Xu
- Department of Pharmaceutics, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Qi Tony Zhou
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907, USA.
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25
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Mechanisms and clinical relevance of bacterial heteroresistance. Nat Rev Microbiol 2019; 17:479-496. [DOI: 10.1038/s41579-019-0218-1] [Citation(s) in RCA: 161] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2019] [Indexed: 02/08/2023]
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Perez F, El Chakhtoura NG, Yasmin M, Bonomo RA. Polymyxins: To Combine or Not to Combine? Antibiotics (Basel) 2019; 8:antibiotics8020038. [PMID: 30974813 PMCID: PMC6627991 DOI: 10.3390/antibiotics8020038] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 04/03/2019] [Accepted: 04/04/2019] [Indexed: 11/16/2022] Open
Abstract
Polymyxins have been a mainstay for the treatment of extensively drug resistant (XDR) Gram-negative bacteria for the past two decades. Many questions regarding the clinical use of polymyxins have been answered, but whether the administration of polymyxins in combination with other antibiotics leads to better outcomes remains unknown. This review discusses the limitations of observational studies that suggest a benefit of combinations of colistin and carbapenems to treat infections caused by carbapenem-resistant Enterobacteriaceae (CRE), especially Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae, and summarizes the results of randomized controlled trials in which treatment with colistin in combination with meropenem or rifampin does not lead to better clinical outcomes than colisitn monotherapy in infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB). Although the introduction of new antibiotics makes it possible to treat certain strains of CRE and carbapenem-resistant P. aeruginosa (CRPA) with polymyxin-sparing regimens, the use of polymyxins is, for now, still necessary in CRAB and in CRE and CRPA harboring metallo-beta-lactamases. Therefore, strategies must be developed to optimize polymyxin-based treatments, informed by in vitro hollow fiber models, careful clinical observations, and high-quality evidence from appropriately designed trials.
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Affiliation(s)
- Federico Perez
- Medicine Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Department of Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA.
- Case VA Center for Antimicrobial Resistance and Epidemiology, Cleveland, OH 44106, USA.
| | - Nadim G El Chakhtoura
- Medicine Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Department of Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA.
| | - Mohamad Yasmin
- Medicine Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
| | - Robert A Bonomo
- Medicine Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Research Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
- Department of Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH 44106, USA.
- Case VA Center for Antimicrobial Resistance and Epidemiology, Cleveland, OH 44106, USA.
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH 44106 USA.
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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The high prevalence of antibiotic heteroresistance in pathogenic bacteria is mainly caused by gene amplification. Nat Microbiol 2019; 4:504-514. [PMID: 30742072 DOI: 10.1038/s41564-018-0342-0] [Citation(s) in RCA: 204] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 12/06/2018] [Indexed: 12/22/2022]
Abstract
When choosing antibiotics to treat bacterial infections, it is assumed that the susceptibility of the target bacteria to an antibiotic is reflected by laboratory estimates of the minimum inhibitory concentration (MIC) needed to prevent bacterial growth. A caveat of using MIC data for this purpose is heteroresistance, the presence of a resistant subpopulation in a main population of susceptible cells. We investigated the prevalence and mechanisms of heteroresistance in 41 clinical isolates of the pathogens Escherichia coli, Salmonella enterica, Klebsiella pneumoniae and Acinetobacter baumannii against 28 different antibiotics. For the 766 bacteria-antibiotic combinations tested, as much as 27.4% of the total was heteroresistant. Genetic analysis demonstrated that a majority of heteroresistance cases were unstable, with an increased resistance of the subpopulations resulting from spontaneous tandem amplifications, typically including known resistance genes. Using mathematical modelling, we show how heteroresistance in the parameter range estimated in this study can result in the failure of antibiotic treatment of infections with bacteria that are classified as antibiotic susceptible. The high prevalence of heteroresistance with the potential for treatment failure highlights the limitations of MIC as the sole criterion for susceptibility determinations. These results call for the development of facile and rapid protocols to identify heteroresistance in pathogens.
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28
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History, Chemistry and Antibacterial Spectrum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:15-36. [DOI: 10.1007/978-3-030-16373-0_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Moffatt JH, Harper M, Boyce JD. Mechanisms of Polymyxin Resistance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:55-71. [PMID: 31364071 DOI: 10.1007/978-3-030-16373-0_5] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Polymyxin antibiotics are increasingly being used as last-line therapeutic options against a number of multidrug resistant bacteria. These antibiotics show strong bactericidal activity against a range of Gram-negative bacteria, but with the increased use of these antibiotics resistant strains are emerging at an alarming rate. Furthermore, some Gram-negative species, such as Neisseria meningitidis, Proteus mirabilis and Burkholderia spp., are intrinsically resistant to the action of polymyxins. Most identified polymyxin resistance mechanisms in Gram-negative bacteria involve changes to the lipopolysaccharide (LPS) structure, as polymyxins initially interact with the negatively charged lipid A component of LPS. The controlled addition of positively charged residues such as 4-amino-L-arabinose, phosphoethanolamine and/or galactosamine to LPS results in a reduced negative charge on the bacterial surface and therefore reduced interaction between the polymyxin and the LPS. Polymyxin resistant species produce LPS that intrinsically contains one or more of these additions. While the genes necessary for most of these additions are chromosomally encoded, plasmid-borne phosphoethanolamine transferases (mcr-1 to mcr-8) have recently been identified and these plasmids threaten to increase the rate of dissemination of clinically relevant colistin resistance. Uniquely, Acinetobacter baumannii can also become highly resistant to polymyxins via spontaneous mutations in the lipid A biosynthesis genes lpxA, lpxC or lpxD such that they produce no LPS or lipid A. A range of other non-LPS-dependent polymyxin resistance mechanisms has also been identified in bacteria, but these generally result in only low levels of resistance. These include increased anionic capsular polysaccharide production in Klebsiella pneumoniae, expression of efflux systems such as MtrCDE in N. meningitidis, and altered expression of outer membrane proteins in a small number of species.
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Affiliation(s)
- Jennifer H Moffatt
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia
| | - Marina Harper
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia.,Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia
| | - John D Boyce
- Biomedicine Discovery Institute, Infection and Immunity Program and Department of Microbiology, Monash University, Clayton, Australia. .,Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia.
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30
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Bergen PJ, Smith NM, Bedard TB, Bulman ZP, Cha R, Tsuji BT. Rational Combinations of Polymyxins with Other Antibiotics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:251-288. [PMID: 31364082 DOI: 10.1007/978-3-030-16373-0_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Combinations of antimicrobial agents are often used in the management of infectious diseases. Antimicrobial agents used as part of combination therapy are often selected empirically. As regrowth and the emergence of polymyxin (either colistin or polymyxin B) resistance has been observed with polymyxin monotherapy, polymyxin combination therapy has been suggested as a possible means by which to increase antimicrobial activity and reduce the development of resistance. This chapter provides an overview of preclinical and clinical investigations of CMS/colistin and polymyxin B combination therapy. In vitro data and animal model data suggests a potential clinical benefit with many drug combinations containing clinically achievable concentrations of polymyxins, even when resistance to one or more of the drugs in combination is present and including antibiotics normally inactive against Gram-negative organisms. The growing body of data on the emergence of polymyxin resistance with monotherapy lends theoretical support to a benefit with combination therapy. Benefits include enhanced bacterial killing and a suppression of polymyxin resistant subpopulations. However, the complexity of the critically ill patient population, and high rates of treatment failure and death irrespective of infection-related outcome make demonstrating a potential benefit for polymyxin combinations extremely challenging. Polymyxin combination therapy in the clinic remains a heavily debated and controversial topic. When combinations are selected, optimizing the dosage regimens for the polymyxin and the combinatorial agent is critical to ensure that the benefits outweigh the risk of the development of toxicity. Importantly, patient characteristics, pharmacokinetics, the site of infection, pathogen and resistance mechanism must be taken into account to define optimal and rational polymyxin combination regimens in the clinic.
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Affiliation(s)
- Phillip J Bergen
- Centre for Medicine Use and Safety, Monash University, Parkville Campus, Melbourne, VIC, Australia.
| | - Nicholas M Smith
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Tyler B Bedard
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Zackery P Bulman
- University of Illinois Chicago, College of Pharmacy, Chicago, IL, USA
| | - Raymond Cha
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Brian T Tsuji
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
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Co-Delivery of Ciprofloxacin and Colistin in Liposomal Formulations with Enhanced In Vitro Antimicrobial Activities against Multidrug Resistant Pseudomonas aeruginosa. Pharm Res 2018; 35:187. [PMID: 30094660 DOI: 10.1007/s11095-018-2464-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/23/2018] [Indexed: 12/20/2022]
Abstract
PURPOSE This study aims to develop liposomal formulations containing synergistic antibiotics of colistin and ciprofloxacin for the treatment of infections caused by multidrug-resistant Pseudomonas aeruginosa. METHODS Colistin (Col) and ciprofloxacin (Cip) were co-encapsulated in anionic liposomes by ammonium sulfate gradient. Particle size, encapsulation efficiency, in vitro drug release and in vitro antibiotic activities were evaluated. RESULTS The optimized liposomal formulation has uniform sizes of approximately 100 nm, with encapsulation efficiency of 67.0% (for colistin) and 85.2% (for ciprofloxacin). Incorporation of anionic lipid (DMPG) markedly increased encapsulation efficiency of colistin (from 5.4 to 67.0%); however, the encapsulation efficiency of ciprofloxacin was independent of DMPG ratio. Incorporation of colistin significantly accelerated the release of ciprofloxacin from the DMPG anionic liposomes. In vitro release of ciprofloxacin and colistin in the bovine serum for 2 h were above 70 and 50%. The cytotoxicity study using A549 cells showed the liposomal formulation is as non-toxic as the drug solutions. Liposomal formulations of combinations had enhanced in vitro antimicrobial activities against multidrug resistant P. aeruginosa than the monotherapies. CONCLUSIONS Liposomal formulations of two synergistic antibiotics was promising against multidrug resistant P. aeruginosa infections.
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Tran TB, Wang J, Doi Y, Velkov T, Bergen PJ, Li J. Novel Polymyxin Combination With Antineoplastic Mitotane Improved the Bacterial Killing Against Polymyxin-Resistant Multidrug-Resistant Gram-Negative Pathogens. Front Microbiol 2018; 9:721. [PMID: 29706941 PMCID: PMC5906568 DOI: 10.3389/fmicb.2018.00721] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/27/2018] [Indexed: 11/13/2022] Open
Abstract
Due to limited new antibiotics, polymyxins are increasingly used to treat multidrug-resistant (MDR) Gram-negative bacteria, in particular carbapenem-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Unfortunately, polymyxin monotherapy has led to the emergence of resistance. Polymyxin combination therapy has been demonstrated to improve bacterial killing and prevent the emergence of resistance. From a preliminary screening of an FDA drug library, we identified antineoplastic mitotane as a potential candidate for combination therapy with polymyxin B against polymyxin-resistant Gram-negative bacteria. Here, we demonstrated that the combination of polymyxin B with mitotane enhances the in vitro antimicrobial activity of polymyxin B against 10 strains of A. baumannii, P. aeruginosa, and K. pneumoniae, including polymyxin-resistant MDR clinical isolates. Time-kill studies showed that the combination of polymyxin B (2 mg/L) and mitotane (4 mg/L) provided superior bacterial killing against all strains during the first 6 h of treatment, compared to monotherapies, and prevented regrowth and emergence of polymyxin resistance in the polymyxin-susceptible isolates. Electron microscopy imaging revealed that the combination potentially affected cell division in A. baumannii. The enhanced antimicrobial activity of the combination was confirmed in a mouse burn infection model against a polymyxin-resistant A. baumannii isolate. As mitotane is hydrophobic, it was very likely that the synergistic killing of the combination resulted from that polymyxin B permeabilized the outer membrane of the Gram-negative bacteria and allowed mitotane to enter bacterial cells and exert its antimicrobial effect. These results have important implications for repositioning non-antibiotic drugs for antimicrobial purposes, which may expedite the discovery of novel therapies to combat the rapid emergence of antibiotic resistance.
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Affiliation(s)
- Thien B. Tran
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Jiping Wang
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Yohei Doi
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Phillip J. Bergen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
- Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
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Hoelzer K, Wong N, Thomas J, Talkington K, Jungman E, Coukell A. Antimicrobial drug use in food-producing animals and associated human health risks: what, and how strong, is the evidence? BMC Vet Res 2017; 13:211. [PMID: 28676125 PMCID: PMC5496648 DOI: 10.1186/s12917-017-1131-3] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 06/23/2017] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Antimicrobial resistance is a public health threat. Because antimicrobial consumption in food-producing animals contributes to the problem, policies restricting the inappropriate or unnecessary agricultural use of antimicrobial drugs are important. However, this link between agricultural antibiotic use and antibiotic resistance has remained contested by some, with potentially disruptive effects on efforts to move towards the judicious or prudent use of these drugs. MAIN TEXT The goal of this review is to systematically evaluate the types of evidence available for each step in the causal pathway from antimicrobial use on farms to human public health risk, and to evaluate the strength of evidence within a 'Grades of Recommendations Assessment, Development and Evaluation'(GRADE) framework. The review clearly demonstrates that there is compelling scientific evidence available to support each step in the causal pathway, from antimicrobial use on farms to a public health burden caused by infections with resistant pathogens. Importantly, the pathogen, antimicrobial drug and treatment regimen, and general setting (e.g., feed type) can have significant impacts on how quickly resistance emerges or spreads, for how long resistance may persist after antimicrobial exposures cease, and what public health impacts may be associated with antimicrobial use on farms. Therefore an exact quantification of the public health burden attributable to antimicrobial drug use in animal agriculture compared to other sources remains challenging. CONCLUSIONS Even though more research is needed to close existing data gaps, obtain a better understanding of how antimicrobial drugs are actually used on farms or feedlots, and quantify the risk associated with antimicrobial use in animal agriculture, these findings reinforce the need to act now and restrict antibiotic use in animal agriculture to those instances necessary to ensure the health and well-being of the animals.
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Affiliation(s)
- Karin Hoelzer
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
| | - Nora Wong
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
| | - Joe Thomas
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
| | - Kathy Talkington
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
| | - Elizabeth Jungman
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
| | - Allan Coukell
- The Pew Charitable Trusts, 901 E Street NW, Washington, DC 20004 USA
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Grégoire N, Aranzana-Climent V, Magréault S, Marchand S, Couet W. Clinical Pharmacokinetics and Pharmacodynamics of Colistin. Clin Pharmacokinet 2017; 56:1441-1460. [DOI: 10.1007/s40262-017-0561-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abdelraouf K, Linder KE, Nailor MD, Nicolau DP. Predicting and preventing antimicrobial resistance utilizing pharmacodynamics: part II Gram-negative bacteria. Expert Opin Drug Metab Toxicol 2017; 13:705-714. [PMID: 28486001 DOI: 10.1080/17425255.2017.1329417] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Antimicrobial resistance is a serious health threat worldwide. Better understanding of exposure targets that could suppress resistance amplification is necessary to guide the dosing of currently available agents as well as new therapies in the drug development process. Areas covered: This review will discuss studies that focused on predicting development of resistance using the pharmacokinetic-pharmacodynamic approach and how to design dosing regimens that can successfully suppress resistance emergence in Gram-negative bacteria. Expert opinion: Pharmacokinetic-pharmacodynamic targets could provide useful insights to guide antimicrobial dosing to prevent resistance emergence. Exposure targets required for resistance suppression are higher than those for efficacy and might not be clinically feasible. Combination therapy is a possible approach to improve the efficacy and minimize the resistance emergence for difficult-to-treat infections.
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Affiliation(s)
- Kamilia Abdelraouf
- a Center for Anti-Infective Research and Development , Hartford Hospital , Hartford , CT , USA
| | - Kristin E Linder
- b Department of Pharmacy , Hartford Hospital , Hartford , CT , USA
| | - Michael D Nailor
- b Department of Pharmacy , Hartford Hospital , Hartford , CT , USA.,c Department of Pharmacy Practice , University of Connecticut School of Pharmacy , Storrs , CT , USA
| | - David P Nicolau
- a Center for Anti-Infective Research and Development , Hartford Hospital , Hartford , CT , USA.,d Division of Infectious Diseases , Hartford Hospital , Hartford , CT , USA
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Cooper TW, Pass SE, Brouse SD, Hall RG. Can Pharmacokinetic and Pharmacodynamic Principles Be Applied to the Treatment of Multidrug-Resistant Acinetobacter? Ann Pharmacother 2017; 45:229-40. [DOI: 10.1345/aph.1p187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE: To discuss treatment options that can be used for treatment of Acinetobacter infections. DATA SOURCES: A MEDLINE search (1966-November 2010) was conducted to identify English-language literature on pharmacotherapy of Acinetobacter and the bibliographies of pertinent articles. Programs and abstracts from infectious diseases meetings were also searched. Search terms included Acinetobacter, multidrug resistance, pharmacokinetics, pharmacodynamics, Monte Carlo simulation, nosocomial pneumonia, carbapenems, polymyxins, sulbactam, aminoglycosides, tetracyclines, tigecycline, rifampin, and fluoroquinolones. DATA SELECTION AND DATA EXTRACTION: All articles were critically evaluated and all pertinent information was included in this review. DATA SYNTHESIS: Multidrug resistant (MDR) Acinetobacter, defined as resistance to 3 or more antimicrobial classes, has increased over the past decade. The incidence of carbapenem-resistant Acinetobacter is also increasing, leading to an increased use of dose optimization techniques and/or alternative antimicrobials, which is driven by local susceptibility patterns. However, Acinetobacter infections that are resistant to all commercially available antibiotics have been reported. General principles are available to guide dose optimization of aminoglycosides, β-lactams, fluoroquinolones, and tigecycline for infections due to gram-negative pathogens. Unfortunately, data specific to patients with Acinetobacter infections are limited. Recent pharmacokinetic-pharmacodynamic information has shed light on colistin dosing. The dilemma with colistin is its concentration-dependent killing, which makes once-daily dosing seem like an attractive option, but its short postantibiotic effect limits a clinician's ability to extend the dosing interval. Localized delivery of antimicrobials is also an attractive option due to the ability to increase drug concentration at the infection site while minimizing systemic adverse events, but more data are needed regarding this approach. CONCLUSIONS: Increased reliance on dosage optimization, combination therapy, and localized delivery of antimicrobials are methods to pursue positive clinical outcomes in MDR Acinetobacter infections since novel antimicrobials will not be available for several years. Well-designed clinical trials with MDR Acinetobacter are needed to define the best treatment options for these patients.
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Antibiotic-non-antibiotic combinations for combating extremely drug-resistant Gram-negative 'superbugs'. Essays Biochem 2017; 61:115-125. [PMID: 28258235 DOI: 10.1042/ebc20160058] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022]
Abstract
The emergence of antimicrobial resistance of Gram-negative pathogens has become a worldwide crisis. The status quo for combating resistance is to employ synergistic combinations of antibiotics. Faced with this fast-approaching post-antibiotic era, it is critical that we devise strategies to prolong and maximize the clinical efficacy of existing antibiotics. Unfortunately, reports of extremely drug-resistant (XDR) Gram-negative pathogens have become more common. Combining antibiotics such as polymyxin B or the broad-spectrum tetracycline and minocycline with various FDA-approved non-antibiotic drugs have emerged as a novel combination strategy against otherwise untreatable XDR pathogens. This review surveys the available literature on the potential benefits of employing antibiotic-non-antibiotic drug combination therapy. The apex of this review highlights the clinical utility of this novel therapeutic strategy for combating infections caused by 'superbugs'.
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Synergy against extensively drug-resistant Acinetobacter baumannii in vitro by two old antibiotics: colistin and chloramphenicol. Int J Antimicrob Agents 2017; 49:321-326. [DOI: 10.1016/j.ijantimicag.2016.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/18/2016] [Accepted: 11/27/2016] [Indexed: 11/17/2022]
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Zusman O, Altunin S, Koppel F, Dishon Benattar Y, Gedik H, Paul M. Polymyxin monotherapy or in combination against carbapenem-resistant bacteria: systematic review and meta-analysis. J Antimicrob Chemother 2016; 72:29-39. [PMID: 27624572 DOI: 10.1093/jac/dkw377] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/01/2016] [Accepted: 08/10/2016] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES The objective of this study was to summarize available data on polymyxin-based combination therapy or monotherapy for carbapenem-resistant Gram-negative bacteria. METHODS This is a systematic review. We included observational studies and randomized controlled trials (RCTs) comparing polymyxin monotherapy versus polymyxin-based combination therapy in adult patients with infections caused by carbapenem-resistant or carbapenemase-producing Gram-negative bacteria. Only named antibiotic regimens were included. The primary outcome was 30 day mortality. Unadjusted OR (uOR) and adjusted OR where available with 95% CI were pooled in random-effects meta-analyses. RESULTS Twenty-two studies including 28 comparisons were included. Polymyxin monotherapy was associated with a uOR of 1.58 (95% CI = 1.03-2.42) for mortality compared with polymyxin/carbapenem combination therapy (seven observational studies, 537 patients), without heterogeneity. Subgrouping studies to serious and critical risk of bias resulted in uORs of 0.94 (95% CI = 0.42-2.09) and 1.94 (95% CI = 1.17-3.23), respectively. Mortality was significantly higher with polymyxin monotherapy compared with combination therapy with tigecycline, aminoglycosides or fosfomycin (potentially double-coverage regimens): uOR of 1.57 (95% CI = 1.06-2.32) overall (10 observational studies and 1 RCT, 585 patients, no heterogeneity) and uOR of 2.09 (95% CI = 1.21-3.6) for Klebsiella pneumoniae bacteraemia (7 observational studies, 285 patients, no heterogeneity); very low quality evidence. Two RCTs and one observational study assessing rifampicin/colistin combination therapy for Acinetobacter baumannii infections showed no difference in mortality compared with colistin monotherapy; moderate quality evidence. CONCLUSIONS The significant association observed in observational studies between polymyxin monotherapy and mortality cannot be taken as proof of combination therapy effects due to the low quality of the evidence. The only three RCTs to date show no effect of rifampicin/colistin or fosfomycin/colistin on mortality for Acinetobacter infections.
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Affiliation(s)
- Oren Zusman
- Department of Medicine E, Rabin Medical Center, Petah-Tiqva, Israel
| | - Sergey Altunin
- Infectious Diseases Unit, Rambam Medical Center, Haifa, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Fidi Koppel
- Infectious Diseases Unit, Rambam Medical Center, Haifa, Israel
| | - Yael Dishon Benattar
- Infectious Diseases Unit, Rambam Medical Center, Haifa, Israel.,The Cheryl Spencer Department of Nursing, University of Haifa, Haifa, Israel
| | - Habip Gedik
- Department of Infectious Diseases and Clinical Microbiology, MoH Bakirkoy Sadi Konuk Training and Research Hospital, Istanbul, Turkey
| | - Mical Paul
- Infectious Diseases Unit, Rambam Medical Center, Haifa, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
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Transcriptomic Analysis of the Activity of a Novel Polymyxin against Staphylococcus aureus. mSphere 2016; 1:mSphere00119-16. [PMID: 27471750 PMCID: PMC4963539 DOI: 10.1128/msphere.00119-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/15/2016] [Indexed: 12/11/2022] Open
Abstract
S. aureus is currently one of the most pervasive multidrug-resistant pathogens and commonly causes nosocomial infections. Clinicians are faced with a dwindling armamentarium to treat infections caused by S. aureus, as resistance develops to current antibiotics. This accentuates the urgent need for antimicrobial drug discovery. In the present study, we characterized the global gene expression profile of S. aureus treated with FADDI-019, a novel synthetic polymyxin analogue. In contrast to the concentration-dependent killing and rapid regrowth in Gram-negative bacteria treated with polymyxin B and colistin, FADDI-019 killed S. aureus progressively without regrowth at 24 h. Notably, FADDI-019 activated several vancomycin resistance genes and significantly downregulated the expression of a number of virulence determinants and enterotoxin genes. A synergistic combination with sulfamethoxazole was predicted by pathway analysis and demonstrated experimentally. This is the first study revealing the transcriptomics of S. aureus treated with a novel synthetic polymyxin analog. Polymyxin B and colistin are exclusively active against Gram-negative pathogens and have been used in the clinic as a last-line therapy. In this study, we investigated the antimicrobial activity of a novel polymyxin, FADDI-019, against Staphylococcus aureus. MIC and time-kill assays were employed to measure the activity of FADDI-019 against S. aureus ATCC 700699. Cell morphology was examined with scanning electron microscopy (SEM), and cell membrane polarity was measured using flow cytometry. Transcriptome changes caused by FADDI-019 treatment were investigated using transcriptome sequencing (RNA-Seq). Pathway analysis was conducted to examine the mechanism of the antibacterial activity of FADDI-019 and to rationally design a synergistic combination. Polymyxin B and colistin were not active against S. aureus strains with MICs of >128 mg/liter; however, FADDI-019 had a MIC of 16 mg/liter. Time-kill assays revealed that no S. aureus regrowth was observed after 24 h at 2× to 4× MIC of FADDI-019. Scanning electron microscopy (SEM) and flow cytometry results indicated that FADDI-019 treatment had no effect on cell morphology but caused membrane depolarization. The vancomycin resistance genes vraRS, as well as the VraRS regulon, were activated by FADDI-019. Virulence determinants controlled by SaeRS and the expression of enterotoxin genes yent2, sei, sem, and seo were significantly downregulated by FADDI-019. Pathway analysis of transcriptomic data was predictive of a synergistic combination comprising FADDI-019 and sulfamethoxazole. Our study is the first to examine the mechanism of the killing of a novel polymyxin against S. aureus. We also show the potential of transcriptomic and pathway analysis as tools to design synergistic antibiotic combinations. IMPORTANCES. aureus is currently one of the most pervasive multidrug-resistant pathogens and commonly causes nosocomial infections. Clinicians are faced with a dwindling armamentarium to treat infections caused by S. aureus, as resistance develops to current antibiotics. This accentuates the urgent need for antimicrobial drug discovery. In the present study, we characterized the global gene expression profile of S. aureus treated with FADDI-019, a novel synthetic polymyxin analogue. In contrast to the concentration-dependent killing and rapid regrowth in Gram-negative bacteria treated with polymyxin B and colistin, FADDI-019 killed S. aureus progressively without regrowth at 24 h. Notably, FADDI-019 activated several vancomycin resistance genes and significantly downregulated the expression of a number of virulence determinants and enterotoxin genes. A synergistic combination with sulfamethoxazole was predicted by pathway analysis and demonstrated experimentally. This is the first study revealing the transcriptomics of S. aureus treated with a novel synthetic polymyxin analog.
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Colistin and Polymyxin B Dosage Regimens against Acinetobacter baumannii: Differences in Activity and the Emergence of Resistance. Antimicrob Agents Chemother 2016; 60:3921-33. [PMID: 27067324 DOI: 10.1128/aac.02927-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 04/05/2016] [Indexed: 12/24/2022] Open
Abstract
Infections caused by multidrug-resistant Acinetobacter baumannii are a major public health problem, and polymyxins are often the last line of therapy for recalcitrant infections by such isolates. The pharmacokinetics of the two clinically used polymyxins, polymyxin B and colistin, differ considerably, since colistin is administered as an inactive prodrug that undergoes slow conversion to colistin. However, the impact of these substantial pharmacokinetic differences on bacterial killing and resistance emergence is poorly understood. We assessed clinically relevant polymyxin B and colistin dosage regimens against one reference and three clinical A. baumannii strains in a dynamic one-compartment in vitro model. A new mechanism-based pharmacodynamic model was developed to describe and predict the drug concentrations and viable counts of the total and resistant populations. Rapid attainment of target concentrations was shown to be critical for polymyxin-induced bacterial killing. All polymyxin B regimens achieved peak concentrations of at least 1 mg/liter within 1 h and caused ≥4 log10 killing at 1 h. In contrast, the slow rise of colistin concentrations to 3 mg/liter over 48 h resulted in markedly reduced bacterial killing. A significant (4 to 6 log10 CFU/ml) amplification of resistant bacterial populations was common to all dosage regimens. The developed mechanism-based model explained the observed bacterial killing, regrowth, and resistance. The model also implicated adaptive polymyxin resistance as a key driver of bacterial regrowth and predicted the amplification of preexisting, highly polymyxin-resistant bacterial populations following polymyxin treatment. Antibiotic combination therapies seem the most promising option for minimizing the emergence of polymyxin resistance.
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Anthelmintic closantel enhances bacterial killing of polymyxin B against multidrug-resistant Acinetobacter baumannii. J Antibiot (Tokyo) 2015; 69:415-21. [PMID: 26669752 PMCID: PMC4911330 DOI: 10.1038/ja.2015.127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/29/2015] [Accepted: 11/08/2015] [Indexed: 12/14/2022]
Abstract
Polymyxins, an old class of antibiotics, are currently used as the last resort for the treatment of multidrug-resistant (MDR) Acinetobacter baumannii. However, recent pharmacokinetic and pharmacodynamic data indicate that monotherapy can lead to the development of resistance. Novel approaches are urgently needed to preserve and improve the efficacy of this last-line class of antibiotics. This study examined the antimicrobial activity of novel combination of polymyxin B with anthelmintic closantel against A. baumannii. Closantel monotherapy (16 mg l(-1)) was ineffective against most tested A. baumannii isolates. However, closantel at 4-16 mg l(-1) with a clinically achievable concentration of polymyxin B (2 mg l(-1)) successfully inhibited the development of polymyxin resistance in polymyxin-susceptible isolates, and provided synergistic killing against polymyxin-resistant isolates (MIC ⩾4 mg l(-1)). Our findings suggest that the combination of polymyxin B with closantel could be potentially useful for the treatment of MDR, including polymyxin-resistant, A. baumannii infections. The repositioning of non-antibiotic drugs to treat bacterial infections may significantly expedite discovery of new treatment options for bacterial 'superbugs'.
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Esterly JS, Richardson CL, Eltoukhy NS, Qi C, Scheetz MH. Genetic Mechanisms of Antimicrobial Resistance of Acinetobacter baumannii. Ann Pharmacother 2015; 45:218-28. [PMID: 21304033 DOI: 10.1345/aph.1p084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To summarize published data identifying known genetic mechanisms of antibiotic resistance in Acinetobacter baumannii and the correlating phenotypic expression of antibiotic resistance. DATA SOURCES MEDLINE databases (1966-July 15, 2010) were searched to identify original reports of genetic mechanisms of antibiotic resistance in A. baumannii. DATA SYNTHESIS Numerous genetic mechanisms of resistance to multiple classes of antibiotics are known to exist in A. baumannii, a gram-negative bacterium increasingly implicated in nosocomial infections. Mechanisms may be constitutive or acquired via plasmids, integrons, and transposons. Methods of resistance include enzymatic modification of antibiotic molecules, modification of antibiotic target sites, expression of efflux pumps, and downregulation of cell membrane porin channel expression. Resistance to β-lactams appears to be primarily caused by β-lactamase production, including extended spectrum β-lactamases (b/aTEM, blaSHV, b/aTX-M,b/aKPC), metallo-β-lactamases (blaMP, blaVIM, bla, SIM), and most commonly, oxacillinases (blaOXA). Antibiotic target site alterations confer resistance to fluoroquinolones (gyrA, parC) and aminoglycosides (arm, rmt), and to a much lesser extent, β-lactams. Efflux pumps (tet, ade, abe) contribute to resistance against β-lactams, tetracyclines, fluoroquinolones, and aminoglycosides. Finally, porin channel deletion (carO, oprD) appears to contribute to β-lactam resistance and may contribute to rarely seen polymyxin resistance. Of note, efflux pumps and porin deletions as solitary mechanisms may not render clinical resistance to A. baumannii. CONCLUSIONS A. baumannii possesses copious genetic resistance mechanisms. Knowledge of local genotypes and expressed phenotypes for A. baumannii may aid clinicians more than phenotypic susceptibilities reported in large epidemiologic studies.
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Affiliation(s)
- John S Esterly
- John S Esterly PharmD BCPS, at time of writing, Infectious Diseases Pharmacotherapy Fellow, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago, Downers Grove, IL; now, Assistant Professor of Pharmacy Practice, College of Pharmacy, Chicago State University, Chicago, IL; Infectious Diseases Pharmacist, Northwestern Memorial Hospital, Chicago
| | - Chad L Richardson
- Chad L Richardson PharmD, at time of writing, Infectious Diseases Pharmacotherapy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; now, Solid Organ Transplant Pharmacist, Northwestern Memorial Hospital
| | - Noha S Eltoukhy
- Noha S Eltoukhy PharmD BCPS, at time of writing, Infectious Diseases Pharmacy Resident, Department of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Rush University Medical Center, Chicago; now, Infectious DIseases Clinical Pharmacy Specialist, St. Mary Medical Center, Langhorne, PA
| | - Chao Qi
- Chao Qi PhD, Assistant Professor of Pathology, Feinberg School of Medicine, Northwestern University; Assistant Director, Clinical Microbiology Laboratory, Northwestern Memorial Hospital, Chicago
| | - Marc H Scheetz
- Marc H Scheetz PharmD MSc BCPS, Assistant Professor of Pharmacy Practice, College of Pharmacy, Midwestern University Chicago; Infectious Diseases Pharmacist, Northwestern Memorial Hospital
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Bergen PJ, Bulman ZP, Landersdorfer CB, Smith N, Lenhard JR, Bulitta JB, Nation RL, Li J, Tsuji BT. Optimizing Polymyxin Combinations Against Resistant Gram-Negative Bacteria. Infect Dis Ther 2015; 4:391-415. [PMID: 26645096 PMCID: PMC4675771 DOI: 10.1007/s40121-015-0093-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Indexed: 01/01/2023] Open
Abstract
Polymyxin combination therapy is increasingly used clinically. However, systematic investigations of such combinations are a relatively recent phenomenon. The emerging pharmacodynamic (PD) and pharmacokinetic (PK) data on CMS/colistin and polymyxin B suggest that caution is required with monotherapy. Given this situation, polymyxin combination therapy has been suggested as a possible way to increase bacterial killing and reduce the development of resistance. Considerable in vitro data have been generated in support of this view, particularly recent studies utilizing dynamic models. However, most existing animal data are of poor quality with major shortcomings in study design, while clinical data are generally limited to retrospective analysis and small, low-power, prospective studies. This article provides an overview of clinical and preclinical investigations of CMS/colistin and polymyxin B combination therapy.
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Affiliation(s)
- Phillip J Bergen
- Centre for Medicine Use and Safety, Monash University, Melbourne, Australia
| | - Zackery P Bulman
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Cornelia B Landersdorfer
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia.,Centre for Medicine Use and Safety, Monash University, Melbourne, Australia
| | - Nicholas Smith
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Justin R Lenhard
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Jürgen B Bulitta
- Center for Pharmacometrics and Systems Pharmacology, Department of Pharmaceutics, College of Pharmacy, University of Florida, Orlando, FL, USA
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Brian T Tsuji
- Laboratory for Antimicrobial Pharmacodynamics, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, SUNY, Buffalo, NY, USA.
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Cheah SE, Wang J, Nguyen VTT, Turnidge JD, Li J, Nation RL. New pharmacokinetic/pharmacodynamic studies of systemically administered colistin against Pseudomonas aeruginosa and Acinetobacter baumannii in mouse thigh and lung infection models: smaller response in lung infection. J Antimicrob Chemother 2015; 70:3291-7. [PMID: 26318190 DOI: 10.1093/jac/dkv267] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 08/04/2015] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES This study investigated the exposure-response relationships between unbound colistin in plasma and antibacterial activity in mouse thigh and lung infections. METHODS Dose fractionation studies (subcutaneous colistin sulphate at 1.25-160 mg/kg/day) were conducted in neutropenic mice in which infection (three strains of Pseudomonas aeruginosa and three strains of Acinetobacter baumannii) had been produced by intramuscular thigh injection or aerosol lung delivery. Bacterial burden was measured at 24 h after initiation of colistin treatment. Plasma protein binding was measured by rapid equilibrium dialysis and ultracentrifugation. The inhibitory sigmoid dose-effect model and non-linear least squares regression were employed to determine the relationship between exposure to unbound colistin and efficacy. RESULTS Plasma binding of colistin was constant over the concentration range ∼2-50 mg/L. The average ± SD percentage bound for all concentrations was 92.9 ± 3.3% by ultracentrifugation and 90.4 ± 1.1% by equilibrium dialysis. In the thigh model, across all six strains the antibacterial effect of colistin was well correlated with fAUC/MIC (R(2) = 0.82-0.94 for P. aeruginosa and R(2) = 0.84-0.95 for A. baumannii). Target values of fAUC/MIC for 2 log10 kill were 7.4-13.7 for P. aeruginosa and 7.4-17.6 for A. baumannii. In the lung model, for only two strains of P. aeruginosa and one strain of A. baumannii was it possible to achieve 2 log10 kill (fAUC/MIC target values 36.8-105), even at the highest colistin dose tolerated by mice. This dose was not able to achieve bacteriostasis for the other two strains of A. baumannii. CONCLUSIONS Colistin was substantially less effective in lung infection. The pharmacokinetic/pharmacodynamic target values will assist in the design of optimized dosage regimens.
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Affiliation(s)
- Soon-Ee Cheah
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - Jiping Wang
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - Van Thi Thu Nguyen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - John D Turnidge
- Departments of Pathology and Paediatrics and School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville campus), Parkville, Victoria 3052, Australia
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Excess Mortality Associated With Colistin-Tigecycline Compared With Colistin-Carbapenem Combination Therapy for Extensively Drug-Resistant Acinetobacter baumannii Bacteremia. Crit Care Med 2015; 43:1194-204. [DOI: 10.1097/ccm.0000000000000933] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Potron A, Poirel L, Nordmann P. Emerging broad-spectrum resistance in Pseudomonas aeruginosa and Acinetobacter baumannii: Mechanisms and epidemiology. Int J Antimicrob Agents 2015; 45:568-85. [PMID: 25857949 DOI: 10.1016/j.ijantimicag.2015.03.001] [Citation(s) in RCA: 451] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 03/05/2015] [Indexed: 02/07/2023]
Abstract
Multidrug resistance is quite common among non-fermenting Gram-negative rods, in particular among clinically relevant species including Pseudomonas aeruginosa and Acinetobacter baumannii. These bacterial species, which are mainly nosocomial pathogens, possess a diversity of resistance mechanisms that may lead to multidrug or even pandrug resistance. Extended-spectrum β-lactamases (ESBLs) conferring resistance to broad-spectrum cephalosporins, carbapenemases conferring resistance to carbapenems, and 16S rRNA methylases conferring resistance to all clinically relevant aminoglycosides are the most important causes of concern. Concomitant resistance to fluoroquinolones, polymyxins (colistin) and tigecycline may lead to pandrug resistance. The most important mechanisms of resistance in P. aeruginosa and A. baumannii and their most recent dissemination worldwide are detailed here.
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Affiliation(s)
- Anaïs Potron
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Laurent Poirel
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland.
| | - Patrice Nordmann
- Emerging Antibiotic Resistance Medical and Molecular Microbiology Unit, Department of Medicine, Faculty of Science, University of Fribourg, Fribourg, Switzerland; HFR - Hôpital Cantonal de Fribourg, Fribourg, Switzerland
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Henry R, Crane B, Powell D, Deveson Lucas D, Li Z, Aranda J, Harrison P, Nation RL, Adler B, Harper M, Boyce JD, Li J. The transcriptomic response of Acinetobacter baumannii to colistin and doripenem alone and in combination in an in vitro pharmacokinetics/pharmacodynamics model. J Antimicrob Chemother 2015; 70:1303-13. [PMID: 25587995 DOI: 10.1093/jac/dku536] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 12/01/2014] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES Colistin remains a last-line treatment for MDR Acinetobacter baumannii and combined use of colistin and carbapenems has shown synergistic effects against MDR strains. In order to understand the bacterial responses to these antibiotics, we analysed the transcriptome of A. baumannii following exposure to each. METHODS RNA sequencing was employed to determine changes in the transcriptome following treatment with colistin and doripenem, both alone and in combination, using an in vitro pharmacokinetics (PK)/pharmacodynamics model to mimic the PK of both antibiotics in patients. RESULTS After treatment with colistin (continuous infusion at 2 mg/L), >400 differentially regulated genes were identified, including many associated with outer membrane biogenesis, fatty acid metabolism and phospholipid trafficking. No genes were differentially expressed following treatment with doripenem (Cmax 25 mg/L, t1/2 1.5 h) for 15 min, but 45 genes were identified as differentially expressed after 1 h of growth under this condition. Treatment of A. baumannii with both colistin and doripenem together for 1 h resulted in >450 genes being identified as differentially expressed. More than 70% of these gene expression changes were also observed following colistin treatment alone. CONCLUSIONS These data suggest that colistin causes gross damage to the outer membrane, facilitates lipid exchange between the inner and outer membrane and alters the normal asymmetric outer membrane composition. The transcriptional response to colistin was highly similar to that observed for an LPS-deficient strain, indicating that many of the observed changes are responses to outer membrane instability resulting from LPS loss.
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Affiliation(s)
- Rebekah Henry
- Department of Microbiology, Monash University, Clayton, Australia
| | - Bethany Crane
- Department of Microbiology, Monash University, Clayton, Australia
| | - David Powell
- Victorian Bioinformatics Consortium, Monash University, Clayton, Australia
| | | | - Zhifeng Li
- Department of Microbiology, Monash University, Clayton, Australia State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, Shandong, P. R. China
| | - Jesús Aranda
- Department of Microbiology, Monash University, Clayton, Australia
| | - Paul Harrison
- Victorian Bioinformatics Consortium, Monash University, Clayton, Australia
| | - Roger L Nation
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
| | - Ben Adler
- Department of Microbiology, Monash University, Clayton, Australia Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia
| | - Marina Harper
- Department of Microbiology, Monash University, Clayton, Australia Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Monash University, Clayton, Australia
| | - John D Boyce
- Department of Microbiology, Monash University, Clayton, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Australia
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49
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An Update on the arsenal for multidrug-resistant Acinetobacter infections: Polymyxin antibiotics. Int J Infect Dis 2015; 30:125-32. [DOI: 10.1016/j.ijid.2014.10.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/14/2014] [Accepted: 10/30/2014] [Indexed: 02/02/2023] Open
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D'Souza BB, Padmaraj SR, Rekha PD, Tellis RC, Prabhu S, Pothen P. In Vitro Synergistic Activity of Colistin and Ceftazidime or Ciprofloxacin Against Multidrug-Resistant Clinical Strains of Pseudomonas aeruginosa. Microb Drug Resist 2014; 20:550-4. [DOI: 10.1089/mdr.2014.0006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Beena Benita D'Souza
- Department of Microbiology, Yenepoya Medical College, Yenepoya University, Mangalore, India
| | - Sunil Rao Padmaraj
- Department of Microbiology, Yenepoya Medical College, Yenepoya University, Mangalore, India
| | | | | | | | - Priyanka Pothen
- Yenepoya Research Centre, Yenepoya University, Mangalore, India
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