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Evseev PV, Sukhova AS, Tkachenko NA, Skryabin YP, Popova AV. Lytic Capsule-Specific Acinetobacter Bacteriophages Encoding Polysaccharide-Degrading Enzymes. Viruses 2024; 16:771. [PMID: 38793652 PMCID: PMC11126041 DOI: 10.3390/v16050771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
The genus Acinetobacter comprises both environmental and clinically relevant species associated with hospital-acquired infections. Among them, Acinetobacter baumannii is a critical priority bacterial pathogen, for which the research and development of new strategies for antimicrobial treatment are urgently needed. Acinetobacter spp. produce a variety of structurally diverse capsular polysaccharides (CPSs), which surround the bacterial cells with a thick protective layer. These surface structures are primary receptors for capsule-specific bacteriophages, that is, phages carrying tailspikes with CPS-depolymerizing/modifying activities. Phage tailspike proteins (TSPs) exhibit hydrolase, lyase, or esterase activities toward the corresponding CPSs of a certain structure. In this study, the data on all lytic capsule-specific phages infecting Acinetobacter spp. with genomes deposited in the NCBI GenBank database by January 2024 were summarized. Among the 149 identified TSPs encoded in the genomes of 143 phages, the capsular specificity (K specificity) of 46 proteins has been experimentally determined or predicted previously. The specificity of 63 TSPs toward CPSs, produced by various Acinetobacter K types, was predicted in this study using a bioinformatic analysis. A comprehensive phylogenetic analysis confirmed the prediction and revealed the possibility of the genetic exchange of gene regions corresponding to the CPS-recognizing/degrading parts of different TSPs between morphologically and taxonomically distant groups of capsule-specific Acinetobacter phages.
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Affiliation(s)
- Peter V. Evseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia;
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
- Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Anastasia S. Sukhova
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
| | - Nikolay A. Tkachenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia;
| | - Yuriy P. Skryabin
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
| | - Anastasia V. Popova
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
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Grygorcewicz B, Gliźniewicz M, Olszewska P, Miłek D, Czajkowski A, Serwin N, Cecerska-Heryć E, Rakoczy R. Response Surface Methodology Application for Bacteriophage-Antibiotic Antibiofilm Activity Optimization. Microorganisms 2023; 11:2352. [PMID: 37764196 PMCID: PMC10536537 DOI: 10.3390/microorganisms11092352] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
Phage-antibiotic combination-based protocols are presently under heightened investigation. This paradigm extends to engagements with bacterial biofilms, necessitating novel computational approaches to comprehensively characterize and optimize the outcomes achievable via these combinations. This study aimed to explore the Response Surface Methodology (RSM) in optimizing the antibiofilm activity of bacteriophage-antibiotic combinations. We employ a combination of antibiotics (gentamicin, meropenem, amikacin, ceftazidime, fosfomycin, imipenem, and colistin) alongside the bacteriophage vB_AbaP_AGC01 to combat Acinetobacter baumannii biofilm. Based on the conducted biofilm challenge assays analyzed using the RSM, the optimal points of antibiofilm activity efficacy were effectively selected by applying this methodology, enabling the quantifiable mathematical representations. Subsequent optimization showed the synergistic potential of the anti-biofilm that arises when antibiotics are judiciously combined with the AGC01 bacteriophage, reducing biofilm biomass by up to 80% depending on the antibiotic used. The data suggest that the phage-imipenem combination demonstrates the highest efficacy, with an 88.74% reduction. Notably, the lower concentrations characterized by a high maximum reduction in biofilm biomass were observed in the phage-amikacin combination at cA = 0.00195 and cP = 0.38 as the option that required minimum resources. It is worth noting that only gentamicin antagonism between the phage and the antibiotic was detected.
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Affiliation(s)
- Bartłomiej Grygorcewicz
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
- Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Piastów Ave. 42, 71-065 Szczecin, Poland;
| | - Marta Gliźniewicz
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Patrycja Olszewska
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Dominika Miłek
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Artur Czajkowski
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Natalia Serwin
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Elżbieta Cecerska-Heryć
- Faculty of Pharmacy, Medical Biotechnology and Laboratory Medicine, Pomeranian Medical University, Powstańców Wielkopolskich 72, 70-111 Szczecin, Poland; (M.G.); (P.O.); (D.M.); (A.C.); (N.S.); (E.C.-H.)
| | - Rafał Rakoczy
- Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology in Szczecin, Piastów Ave. 42, 71-065 Szczecin, Poland;
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Abedon ST. Automating Predictive Phage Therapy Pharmacology. Antibiotics (Basel) 2023; 12:1423. [PMID: 37760719 PMCID: PMC10525195 DOI: 10.3390/antibiotics12091423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/02/2023] [Accepted: 09/03/2023] [Indexed: 09/29/2023] Open
Abstract
Viruses that infect as well as often kill bacteria are called bacteriophages, or phages. Because of their ability to act bactericidally, phages increasingly are being employed clinically as antibacterial agents, an infection-fighting strategy that has been in practice now for over one hundred years. As with antibacterial agents generally, the development as well as practice of this phage therapy can be aided via the application of various quantitative frameworks. Therefore, reviewed here are considerations of phage multiplicity of infection, bacterial likelihood of becoming adsorbed as a function of phage titers, bacterial susceptibility to phages also as a function of phage titers, and the use of Poisson distributions to predict phage impacts on bacteria. Considered in addition is the use of simulations that can take into account both phage and bacterial replication. These various approaches can be automated, i.e., by employing a number of online-available apps provided by the author, the use of which this review emphasizes. In short, the practice of phage therapy can be aided by various mathematical approaches whose implementation can be eased via online automation.
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Affiliation(s)
- Stephen T Abedon
- Department of Microbiology, The Ohio State University, Mansfield, OH 44906, USA
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Osman AH, Kotey FCN, Odoom A, Darkwah S, Yeboah RK, Dayie NTKD, Donkor ES. The Potential of Bacteriophage-Antibiotic Combination Therapy in Treating Infections with Multidrug-Resistant Bacteria. Antibiotics (Basel) 2023; 12:1329. [PMID: 37627749 PMCID: PMC10451467 DOI: 10.3390/antibiotics12081329] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/04/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023] Open
Abstract
The growing threat of antibiotic resistance is a significant global health challenge that has intensified in recent years. The burden of antibiotic resistance on public health is augmented due to its multifaceted nature, as well as the slow-paced and limited development of new antibiotics. The threat posed by resistance is now existential in phage therapy, which had long been touted as a promising replacement for antibiotics. Consequently, it is imperative to explore the potential of combination therapies involving antibiotics and phages as a feasible alternative for treating infections with multidrug-resistant bacteria. Although either bacteriophage or antibiotics can potentially treat bacterial infections, they are each fraught with resistance. Combination therapies, however, yielded positive outcomes in most cases; nonetheless, a few combinations did not show any benefit. Combination therapies comprising the synergistic activity of phages and antibiotics and combinations of phages with other treatments such as probiotics hold promise in the treatment of drug-resistant bacterial infections.
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Affiliation(s)
| | | | | | | | | | | | - Eric S. Donkor
- Department of Medical Microbiology, University of Ghana Medical School, Korle Bu, Accra P.O. Box KB 4236, Ghana; (A.-H.O.); (F.C.N.K.); (A.O.); (S.D.); (R.K.Y.); (N.T.K.D.D.)
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Hao X, Cen X, He M, Wen Y, Zhang H. Isolation, biological and whole genome characteristics of a Proteus mirabilis bacteriophage strain. BMC Microbiol 2023; 23:215. [PMID: 37553593 PMCID: PMC10410936 DOI: 10.1186/s12866-023-02960-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 07/25/2023] [Indexed: 08/10/2023] Open
Abstract
Proteus mirabilis, a naturally resistant zoonotic bacterium belonging to the Enterobacteriaceae family, has exhibited an alarming increase in drug resistance. Consequently, there is an urgent need to explore alternative antimicrobial agents. Bacteriophages, viruses that selectively target bacteria, are abundant in the natural environment and have demonstrated potential as a promising alternative to antibiotics. In this study, we successfully isolated four strains of Proteus mirabilis phages from sewage obtained from a chicken farm in Sichuan, China. Subsequently, we characterized one of the most potent lytic phages, Q29, by examining its biological and genomic features. Comparative genomic analysis revealed the functional genes and phylogenetic evolution of Q29 phages. Our findings revealed that Proteus mirabilis bacteriophage Q29 possesses an icosahedral symmetrical head with a diameter of 95 nm and a tail length of 240 nm. Moreover, phage Q29 exhibited stability within a temperature range of 37 ℃ to 55 ℃ and under pH conditions ranging from 4 to 9. The optimal multiplicity of infection (MOI) for this phage was determined to be 0.001. Furthermore, the one-step growth curve results indicated an incubation period of approximately 15 min, an outbreak period of approximately 35 min, and an average cleavage quantity of approximately 60 plaque-forming units (PFU) per cell. The genome of phage Q29 was found to have a total length of 58,664 base pairs and encoded 335 open reading frames (ORFs) without carrying any antibiotic resistance genes. Additionally, genetic evolutionary analysis classified phage Q29 within the family Caudalidae and the genus Myotail. This study provides valuable research material for further development of Proteus mirabilis bacteriophage biologics as promising alternatives to antibiotics, particularly in light of the growing challenge of antibiotic resistance posed by this bacterium.
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Affiliation(s)
- Xirui Hao
- College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, Sichuan, China
- Key Laboratory of Veterinary Medicine of Universities in Sichuan, Chengdu, PR China
| | - Xin Cen
- College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, Sichuan, China
- Key Laboratory of Veterinary Medicine of Universities in Sichuan, Chengdu, PR China
| | - Min He
- College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, Sichuan, China
- Key Laboratory of Veterinary Medicine of Universities in Sichuan, Chengdu, PR China
| | - Yongping Wen
- College of Food and Biological Engineering, Chengdu University, Chengdu, 610106, Sichuan, China
| | - Huanrong Zhang
- College of Animal and Veterinary Sciences, Southwest Minzu University, Chengdu, 610041, Sichuan, China.
- Key Laboratory of Veterinary Medicine of Universities in Sichuan, Chengdu, PR China.
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Tu Q, Pu M, Li Y, Wang Y, Li M, Song L, Li M, An X, Fan H, Tong Y. Acinetobacter Baumannii Phages: Past, Present and Future. Viruses 2023; 15:v15030673. [PMID: 36992382 PMCID: PMC10057898 DOI: 10.3390/v15030673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/23/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is one of the most common clinical pathogens and a typical multi-drug resistant (MDR) bacterium. With the increase of drug-resistant A. baumannii infections, it is urgent to find some new treatment strategies, such as phage therapy. In this paper, we described the different drug resistances of A. baumannii and some basic properties of A. baumannii phages, analyzed the interaction between phages and their hosts, and focused on A. baumannii phage therapies. Finally, we discussed the chance and challenge of phage therapy. This paper aims to provide a more comprehensive understanding of A. baumannii phages and theoretical support for the clinical application of A. baumannii phages.
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Affiliation(s)
- Qihang Tu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Mingfang Pu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yahao Li
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), Beijing University of Chemical Technology, Beijing 100029, China
| | - Yuer Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Maochen Li
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lihua Song
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Mengzhe Li
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaoping An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Huahao Fan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
- Correspondence: (H.F.); (Y.T.)
| | - Yigang Tong
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering (BAIC-SM), Beijing University of Chemical Technology, Beijing 100029, China
- Correspondence: (H.F.); (Y.T.)
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Suh GA, Patel R. Clinical phage microbiology: a narrative summary. Clin Microbiol Infect 2023:S1198-743X(23)00059-9. [PMID: 36805835 DOI: 10.1016/j.cmi.2023.02.006] [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: 09/26/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/17/2023]
Abstract
BACKGROUND Although phage therapy has been in existence for a century, a recent resurgence in interest has occurred because of the continued emergence of antimicrobial resistance and the rising use of indwelling medical devices, resulting in biofilm-associated infections, for which conventional antibiotics are of limited use. Despite this, the clinical successes have been inconsistent because of multiple reasons, including (1) the narrow host range of phages, (2) challenges with concentrating phages at the site of infection, (3) development of resistance of bacteria to phages and (4) immune neutralization. Microbiologic assays have the potential to help guide the course of clinical therapy and improve outcomes. Methods developed decades ago remain the mainstay of phage diagnostics and recently, newer diagnostics are closing the gap needed to further advance clinical phage therapy. OBJECTIVES To review the current state of clinical phage microbiology and identify gaps. SOURCES A PubMed search was performed using the terms "phage microbiology", "phage susceptibility test", "phage host range", "phage biofilm", and "phage therapeutic monitoring". CONTENT Phage susceptibility testing, biofilm assays, phage-antibiotic combination testing, therapeutic drug monitoring, and immune monitoring assays are the current foundation for clinical phage diagnostics. Standardization of these assays and better understanding as to if and how they should be used in terms of clinical management of patients receiving phage therapy is needed. IMPLICATIONS A substantial gap between in vitro studies and in vivo outcomes indicates that further work is needed in phage pharmacokinetics to accurately assay phage particles at the site of infection; recapitulate in vivo biofilm; capture the complex interactions between phages and antibiotics, phages and their target bacteria, among phages in a cocktail, and with the superhost immune system.
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Affiliation(s)
- Gina A Suh
- Division of Public Health, Infectious Diseases, and Occupational Medicine, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
| | - Robin Patel
- Division of Public Health, Infectious Diseases, and Occupational Medicine, Department of Medicine, Mayo Clinic, Rochester, MN, USA; Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
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Zhang Y, Lin Y, Galgano S, Houdijk J, Xie W, Jin Y, Lin J, Song W, Fu Y, Li X, Chui W, Kan W, Jia C, Hu G, Li T. Recent Progress in Phage Therapy to Modulate Multidrug-Resistant Acinetobacter baumannii, including in Human and Poultry. Antibiotics (Basel) 2022; 11:1406. [PMID: 36290064 PMCID: PMC9598230 DOI: 10.3390/antibiotics11101406] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/28/2022] [Accepted: 10/03/2022] [Indexed: 07/30/2023] Open
Abstract
Acinetobacter baumannii is a multidrug-resistant and invasive pathogen associated with the etiopathology of both an increasing number of nosocomial infections and is of relevance to poultry production systems. Multidrug-resistant Acinetobacter baumannii has been reported in connection to severe challenges to clinical treatment, mostly due to an increased rate of resistance to carbapenems. Amid the possible strategies aiming to reduce the insurgence of antimicrobial resistance, phage therapy has gained particular importance for the treatment of bacterial infections. This review summarizes the different phage-therapy approaches currently in use for multiple-drug resistant Acinetobacter baumannii, including single phage therapy, phage cocktails, phage-antibiotic combination therapy, phage-derived enzymes active on Acinetobacter baumannii and some novel technologies based on phage interventions. Although phage therapy represents a potential treatment solution for multidrug-resistant Acinetobacter baumannii, further research is needed to unravel some unanswered questions, especially in regard to its in vivo applications, before possible routine clinical use.
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Affiliation(s)
- Yan Zhang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Yuanqing Lin
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Salvatore Galgano
- Monogastric Science Research Centre, Scotland’s Rural College, Roslin Institute Building, Edinburgh EH25 9RG, UK
| | - Jos Houdijk
- Monogastric Science Research Centre, Scotland’s Rural College, Roslin Institute Building, Edinburgh EH25 9RG, UK
| | - Weiquan Xie
- School of Pharmacy, Guilin Medical University, Guilin 541199, China
| | - Yajie Jin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Jiameng Lin
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
| | - Wuqiang Song
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
- School of Pharmacy, Guilin Medical University, Guilin 541199, China
| | - Yijuan Fu
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Xiuying Li
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Wenting Chui
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Wei Kan
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Cai Jia
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Guangwei Hu
- Animal Disease Prevention and Control Center in Qinghai Province, Xining 810001, China
| | - Tao Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Shanghai 200241, China
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An Optimized Checkerboard Method for Phage-Antibiotic Synergy Detection. Viruses 2022; 14:v14071542. [PMID: 35891522 PMCID: PMC9319746 DOI: 10.3390/v14071542] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 12/10/2022] Open
Abstract
Phage-antibiotic synergy is a promising therapeutic strategy, but there is no reliable method for synergism estimation. Although the time-kill curve assay is a gold standard, the method is not appropriate for fast and extensive screening of the synergy. The aim is to optimize the checkerboard method to determine phage-chemical agent interactions, to check its applicability by the time-kill curve method, and to examine whether the synergy can be obtained with both simultaneous and successive applications of these agents. In addition, the aim is to determine interactions of the Pseudomonas phage JG024 with ciprofloxacin, gentamicin, or ceftriaxone, as well as the Staphylococcus phage MSA6 and SES43300 with ciprofloxacin, gentamicin, and oxacillin. The results show that the optimized checkerboard method is reliable and that results correspond to those obtained by the time-kill curve. The synergy is detected with the phage JG024 and ciprofloxacin or ceftriaxone against Pseudomonas aeruginosa, and the phage SES43300 with ciprofloxacin against MRSA. The synergy was obtained after simultaneous applications, and in the case of P. aeruginosa, after application of the second agent with delay of one hour, indicating that simultaneous application is the best mode of synergy exploitation for therapy. The checkerboard method can be used for thorough clinical studies on synergy and in the future for personalized therapy when infections are caused by multiple resistant bacteria.
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