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Chen C, Shi J, Wang D, Kong P, Wang Z, Liu Y. Antimicrobial peptides as promising antibiotic adjuvants to combat drug-resistant pathogens. Crit Rev Microbiol 2024; 50:267-284. [PMID: 36890767 DOI: 10.1080/1040841x.2023.2186215] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 07/19/2022] [Accepted: 10/26/2022] [Indexed: 03/10/2023]
Abstract
The widespread antimicrobial resistance (AMR) calls for the development of new antimicrobial strategies. Antibiotic adjuvant rescues antibiotic activity and increases the life span of the antibiotics, representing a more productive, timely, and cost-effective strategy in fighting drug-resistant pathogens. Antimicrobial peptides (AMPs) from synthetic and natural sources are considered new-generation antibacterial agents. Besides their direct antimicrobial activity, growing evidence shows that some AMPs effectively enhance the activity of conventional antibiotics. The combinations of AMPs and antibiotics display an improved therapeutic effect on antibiotic-resistant bacterial infections and minimize the emergence of resistance. In this review, we discuss the value of AMPs in the age of resistance, including modes of action, limiting evolutionary resistance, and their designing strategies. We summarise the recent advances in combining AMPs and antibiotics against antibiotic-resistant pathogens, as well as their synergistic mechanisms. Lastly, we highlight the challenges and opportunities associated with the use of AMPs as potential antibiotic adjuvants. This will shed new light on the deployment of synergistic combinations to address the AMR crisis.
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Affiliation(s)
- Chen Chen
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Jingru Shi
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Dejuan Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Pan Kong
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zhiqiang Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yuan Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education of China, Yangzhou University, Yangzhou, China
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2
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Chatupheeraphat C, Peamchai J, Luk-in S, Yainoy S, Eiamphungporn W. Synergistic effect of two antimicrobial peptides, BP203 and MAP-0403 J-2 with conventional antibiotics against colistin-resistant Escherichia coli and Klebsiella pneumoniae clinical isolates. PLoS One 2023; 18:e0294287. [PMID: 37972089 PMCID: PMC10653547 DOI: 10.1371/journal.pone.0294287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023] Open
Abstract
Drug-resistant Enterobacterales infections are a great health concern due to the lack of effective treatments. Consequently, finding novel antimicrobials or combining therapies becomes a crucial approach in addressing this problem. BP203 and MAP-0403 J-2, novel antimicrobial peptides, have exhibited effectiveness against Gram-negative bacteria. In this study, we assessed the in vitro antibacterial activity of BP203 and MAP-0403 J-2, along with their synergistic interaction with conventional antibiotics including colistin, rifampicin, chloramphenicol, ceftazidime, meropenem, and ciprofloxacin against colistin-resistant Escherichia coli and Klebsiella pneumoniae clinical isolates. The minimal inhibitory concentrations (MIC) of BP203 and MAP-0403 J-2 against tested E. coli isolates were 2-16 and 8-32 μg/mL, respectively. However, for the majority of K. pneumoniae isolates, the MIC of BP203 and MAP-0403 J-2 were >128 μg/mL. Notably, our results demonstrated a synergistic effect when combining BP203 with rifampicin, meropenem, or chloramphenicol, primarily observed in most K. pneumoniae isolates. In contrast, no synergism was evident between BP203 and colistin, chloramphenicol, ceftazidime, rifampicin, or ciprofloxacin when tested against all E. coli isolates. Furthermore, synergistic effects between MAP-0403 J-2 and rifampicin, ceftazidime or colistin were observed against the majority of E. coli isolates. Similarly, the combined effect of MAP-0403 J-2 with rifampicin or chloramphenicol was synergistic in the majority of K. pneumoniae isolates. Importantly, these peptides displayed the stability at high temperatures, across a wide range of pH values, in specific serum concentrations and under physiological salt conditions. Both peptides also showed no significant hemolysis and cytotoxicity against mammalian cells. Our findings suggested that BP203 and MAP-0403 J-2 are promising candidates against colistin-resistant E. coli. Meanwhile, the synergism of these peptides and certain antibiotics could be of great therapeutic value as antimicrobial drugs against infections caused by colistin-resistant E. coli and K. pneumoniae.
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Affiliation(s)
- Chawalit Chatupheeraphat
- Center for Research Innovation and Biomedical Informatics, Faculty of Medical Technology, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Jiratchaya Peamchai
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Sirirat Luk-in
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Sakda Yainoy
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Warawan Eiamphungporn
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
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Lennard PR, Hiemstra PS, Nibbering PH. Complementary Activities of Host Defence Peptides and Antibiotics in Combating Antimicrobial Resistant Bacteria. Antibiotics (Basel) 2023; 12:1518. [PMID: 37887219 PMCID: PMC10604037 DOI: 10.3390/antibiotics12101518] [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: 09/01/2023] [Revised: 09/27/2023] [Accepted: 10/02/2023] [Indexed: 10/28/2023] Open
Abstract
Due to their ability to eliminate antimicrobial resistant (AMR) bacteria and to modulate the immune response, host defence peptides (HDPs) hold great promise for the clinical treatment of bacterial infections. Whereas monotherapy with HDPs is not likely to become an effective first-line treatment, combinations of such peptides with antibiotics can potentially provide a path to future therapies for AMR infections. Therefore, we critically reviewed the recent literature regarding the antibacterial activity of combinations of HDPs and antibiotics against AMR bacteria and the approaches taken in these studies. Of the 86 studies compiled, 56 featured a formal assessment of synergy between agents. Of the combinations assessed, synergistic and additive interactions between HDPs and antibiotics amounted to 84.9% of the records, while indifferent and antagonistic interactions accounted for 15.1%. Penicillin, aminoglycoside, fluoro/quinolone, and glycopeptide antibiotic classes were the most frequently documented as interacting with HDPs, and Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecium were the most reported bacterial species. Few studies formally evaluated the effects of combinations of HDPs and antibiotics on bacteria, and even fewer assessed such combinations against bacteria within biofilms, in animal models, or in advanced tissue infection models. Despite the biases of the current literature, the studies suggest that effective combinations of HDPs and antibiotics hold promise for the future treatment of infections caused by AMR bacteria.
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Affiliation(s)
- Patrick R. Lennard
- Centre for Inflammation Research, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh EH16 4UU, UK
- Institute of Immunology and Infection, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FE, UK
- PulmoScience Lab, Department of Pulmonology, Leiden University Medical Centre, Leiden 2333, The Netherlands
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden 2333, The Netherlands;
| | - Pieter S. Hiemstra
- PulmoScience Lab, Department of Pulmonology, Leiden University Medical Centre, Leiden 2333, The Netherlands
| | - Peter H. Nibbering
- Department of Infectious Diseases, Leiden University Medical Centre, Leiden 2333, The Netherlands;
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Ugurel E, Turgut-Balik D. Synergistic combination of carvedilol, amlodipine, amitriptyline, and antibiotics as an alternative treatment approach for the susceptible and multidrug-resistant A. baumannii infections via drug repurposing. Eur J Clin Microbiol Infect Dis 2023; 42:1063-1072. [PMID: 37428238 DOI: 10.1007/s10096-023-04634-5] [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: 02/27/2023] [Accepted: 05/15/2023] [Indexed: 07/11/2023]
Abstract
We evaluated in vitro activity of 13 drugs used in the treatment of some non-communicable diseases via repurposing to determine their potential use in the treatment of Acinetobacter baumannii infections caused by susceptible and multidrug-resistant strains. A. baumannii is a multidrug-resistant Gram-negative bacteria causing nosocomial infections, especially in intensive care units. It has been identified in the WHO critical pathogen list and this emphasises urgent need for new treatment options. As the development of new therapeutics is expensive and time consuming, finding new uses of existing drugs via drug repositioning has been favoured. Antimicrobial susceptibility tests were conducted on all 13 drugs according to CLSI. Drugs with MIC values below 128 μg/mL and control antibiotics were further subjected to synergetic effect and bacterial time-kill analysis. Carvedilol-gentamicin (FICI 0.2813) and carvedilol-amlodipine (FICI 0.5625) were determined to have synergetic and additive effect, respectively, on the susceptible A. baumannii strain, and amlodipine-tetracycline (FICI 0.75) and amitriptyline-tetracycline (FICI 0.75) to have additive effect on the multidrug-resistant A. baumannii strain. Most remarkably, both amlodipine and amitriptyline reduced the MIC of multidrug-resistant, including some carbapenems, A. baumannii reference antibiotic tetracycline from 2 to 0.5 μg/mL, for 4-folds. All these results were further supported by bacterial time-kill assay and all combinations showed bactericidal activity, at certain hours, at 4XMIC. Combinations proposed in this study may provide treatment options for both susceptible and multidrug-resistant A. baumannii infections but requires further pharmacokinetics and pharmacodynamics analyses and in vivo re-evaluations using appropriate models.
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Affiliation(s)
- Erennur Ugurel
- Faculty of Chemical and Metallurgical Engineering, Department of Bioengineering, Yildiz Technical University, Davutpasa Campus, 34210, Esenler, Istanbul, Türkiye
| | - Dilek Turgut-Balik
- Faculty of Chemical and Metallurgical Engineering, Department of Bioengineering, Yildiz Technical University, Davutpasa Campus, 34210, Esenler, Istanbul, Türkiye.
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Morici P, Rizzato C, Ghelardi E, Rossolini GM, Lupetti A. Sensitization of KPC and NDM Klebsiella pneumoniae To Rifampicin by the Human Lactoferrin-Derived Peptide hLF1-11. Microbiol Spectr 2023; 11:e0276722. [PMID: 36537823 PMCID: PMC9927577 DOI: 10.1128/spectrum.02767-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
A synergistic effect of non-bactericidal concentrations of the human lactoferrin (hLF)-derived peptide hLF1-11 and rifampicin against multidrug-resistant KPC (Klebsiella pneumoniae carbapenemase)-producing K. pneumoniae has been previously shown. The present study focuses on the mechanism(s) underlying this synergistic effect. The contribution of hLF1-11 and rifampicin to the synergistic effect was evaluated by killing assays with KPC K. pneumoniae cells incubated with hLF1-11 and, after washing, with rifampicin, or vice versa. Cell membrane permeability and polarization upon exposure to hLF1-11 and/or rifampicin were evaluated by ethidium bromide (EtBr) and DiBAC4(3) (bis-1,3-dibutylbarbituric acid trimethine oxonol) permeability, respectively. The effect of carbonyl cyanide m-chlorophenyl hydrazone (CCCP), an uncoupler of oxidative phosphorylation, was also evaluated. KPC K. pneumoniae cells were effectively killed after prior exposure to rifampicin for 30 to 60 min followed by treatment with hLF1-11, while no antibacterial activity was observed when cells were incubated with hLF1-11 first and then with rifampicin. EtBr accumulation increased upon exposure to hLF1-11 or the combination of hLF1-11 and rifampicin, but not upon exposure to rifampicin alone. Moreover, hLF1-11 induced a dose-dependent membrane depolarization. As expected, the antibacterial activity of hLF1-11 alone or combined with rifampicin was significantly reduced in the presence of CCCP. Furthermore, hLF1-11 and rifampicin were synergistic also against a colistin-resistant NDM (New Delhi metallo-β-lactamase)-producing K. pneumoniae strain. The results suggest that rifampicin was accumulated by KPC cells during the 30-to-60-min incubation and that the addition of hLF1-11 sensitized bacterial cells to rifampicin by inducing a transient loss of membrane potential and increased cell membrane permeability, thus facilitating the entrance and retention of rifampicin into the cytoplasm. IMPORTANCE The present study describes a synergistic effect between rifampicin, an impermeable hydrophobic antibiotic with an intracellular target, and an hLF1-11, an antimicrobial peptide derived from human lactoferrin, against multidrug-resistant Klebsiella pneumoniae. Carbapenem-resistant K. pneumoniae has recently caused an outbreak in Tuscany, Italy, thus pressing the need for the development of new treatment options. The mechanisms underlying such a synergistic effect have been studied. The results suggest that the synergistic effect was due to the transient loss of membrane potential induced by hLF1-11 and the subsequent increase in cell membrane permeability which allowed rifampicin to enter the bacterial cell. Therefore, it is likely that a sub-inhibitory concentration of hLF1-11 can efficiently permeabilize K. pneumoniae cells to rifampicin, allowing the antibiotic to reach its intracellular target. These results encourage further exploration of possible applications of this synergistic combination in the treatment of K. pneumoniae infections.
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Affiliation(s)
- Paola Morici
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Cosmeri Rizzato
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Emilia Ghelardi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
- Clinical Microbiology and Virology Unit, Florence Careggi University Hospital, Florence, Italy
| | - Antonella Lupetti
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
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Chatupheeraphat C, Peamchai J, Luk-in S, Eiamphungporn W. Synergistic effect and antibiofilm activity of the antimicrobial peptide K11 with conventional antibiotics against multidrug-resistant and extensively drug-resistant Klebsiella pneumoniae. Front Cell Infect Microbiol 2023; 13:1153868. [PMID: 37113135 PMCID: PMC10126264 DOI: 10.3389/fcimb.2023.1153868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 03/21/2023] [Indexed: 04/29/2023] Open
Abstract
Introduction Infections caused by drug-resistant Klebsiella pneumoniae are now a serious problem for public health, associated with high morbidity and mortality due to limited treatment options. Therefore, new antibacterial agents or a combination of agents as the first line of treatment are urgently needed. K11 is a novel antimicrobial peptide (AMP) that has demonstrated in vitro antimicrobial activity against several types of bacteria. Additionally, K11 has previously shown no hemolytic activity. Herein, the antibacterial activity, the synergistic action of K11 in combination with different conventional antibiotics and the antibiofilm activity of K11 against multidrug-resistant (MDR) and extensively drug-resistant (XDR) K. pneumoniae were investigated. Meanwhile, the stability and ability to induce the bacterial resistance of K11 were also tested. Methods Fifteen clinical isolates of MDR/XDR K. pneumoniae were used in this study. The minimum inhibitory concentration (MIC) of K11 against these isolates was determined by the broth microdilution method. In vitro synergy between K11 and antibiotics was evaluated using the checkerboard methodology. The antibiofilm activity of K11 against K. pneumoniae strong biofilm producers were explored by the crystal violet staining. The stability in different environments and resistance induction of K11 were evaluated by MIC determination. Results The MIC values of K11 against MDR/XDR K. pneumoniae isolates were 8-512 μg/mL. Intriguingly, the synergistic effects were clearly observed for K11 in combination with chloramphenicol, meropenem, rifampicin, or ceftazidime, whereas no synergy was observed when K11 was combined with colistin. Besides, K11 effectively prevented biofilm formation against K. pneumoniae strong biofilm producers in a concentration-dependent manner starting at 0.25×MIC and exerted an enhancing effect when administered in combination with meropenem, chloramphenicol, or rifampicin. Additionally, K11 demonstrated high thermal and wide pH stability along with good stability in serum and physiological salts. Significantly, K. pneumoniae showed no induction of resistance even after prolonged exposure to a sub-inhibitory concentration of K11. Conclusion These findings indicate that K11 is a promising candidate with potent antibacterial and antibiofilm activities without inducing resistance and acts synergistically with conventional antibiotics against drug-resistant K. pneumoniae.
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Affiliation(s)
- Chawalit Chatupheeraphat
- Center for Research and Innovation, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Jiratchaya Peamchai
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Sirirat Luk-in
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Warawan Eiamphungporn
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
- *Correspondence: Warawan Eiamphungporn,
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Chowdhury AR, Mukherjee D, Singh AK, Chakravortty D. Loss of outer membrane protein A (OmpA) impairs the survival of Salmonella Typhimurium by inducing membrane damage in the presence of ceftazidime and meropenem. J Antimicrob Chemother 2022; 77:3376-3389. [PMID: 36177811 DOI: 10.1093/jac/dkac327] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/05/2022] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Salmonella enterica serovar Typhimurium is one of the significant non-typhoidal Salmonella serovars that causes gastroenteritis. The rapid development of antimicrobial resistance necessitates studying new antimicrobials and their therapeutic targets in this pathogen. Our study aimed to investigate the role of four prominent outer membrane porins of S. Typhimurium, namely OmpA, OmpC, OmpD and OmpF, in developing resistance against ceftazidime and meropenem. METHODS The antibiotic-mediated inhibition of bacterial growth was determined by measuring the absorbance and the resazurin assay. DiBAC4 (Bis-(1,3-Dibutylbarbituric Acid)Trimethine Oxonol), 2,7-dichlorodihydrofluoroscein diacetate (DCFDA) and propidium iodide were used to determine the outer membrane depolarization, reactive oxygen species (ROS) generation and subsequent killing of Salmonella. The expression of oxidative stress-response and efflux pump genes was quantified by quantitative RT-qPCR. HPLC was done to determine the amount of antibiotics that entered the bacteria. The damage to the bacterial outer membrane was studied by confocal and atomic force microscopy. The in vivo efficacy of ceftazidime and meropenem were tested in the C57BL/6 mouse model. RESULTS Deleting ompA reduced the survival of Salmonella in the presence of ceftazidime and meropenem. Massive outer membrane depolarization and reduced expression of oxidative stress-response genes in S. Typhimurium ΔompA hampered its growth in the presence of antibiotics. The enhanced uptake of antibiotics and decreased expression of efflux pump genes in S. Typhimurium ΔompA resulted in damage to the bacterial outer membrane. The clearance of the S. Typhimurium ΔompA from C57BL/6 mice with ceftazidime treatment proved the role of OmpA in rendering protection against β-lactam antibiotics. CONCLUSIONS OmpA protects S. Typhimurium from two broad-spectrum β-lactam antibiotics, ceftazidime and meropenem, by maintaining the stability of the outer membrane.
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Affiliation(s)
- Atish Roy Chowdhury
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.,Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Debapriya Mukherjee
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.,Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Ashish Kumar Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.,Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.,Division of Biological Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India.,School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
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Prevalence of Extended-Spectrum β-Lactamase-Resistant Genes in Escherichia coli Isolates from Central China during 2016-2019. Animals (Basel) 2022; 12:ani12223191. [PMID: 36428418 PMCID: PMC9686871 DOI: 10.3390/ani12223191] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/04/2022] [Accepted: 11/15/2022] [Indexed: 11/19/2022] Open
Abstract
The emergence and dissemination of Escherichia coli (E. coli) strains that produce extended-spectrum beta-lactamases (ESBLs) represents a major public health threat. The present study was designed to evaluate the prevalence and characteristics of ESBL-producing Escherichia coli isolates from chickens in central China during 2016-2019. A total of 407 E. coli strains isolated from 581 chicken swabs were identified conventionally and analyzed for various cephalosporin susceptibility by disk-diffusion assay. ESBL-producing strains were screened using the double=disk synergy test and ESBL-encoding genes were carried out by PCR/sequencing. A total of 402 E. coli isolates exhibited strong resistance to first- to fourth-generation cephalosporins and monobactam antibiotics, especially cefazolin (60.69%), cefuroxime (54.05%), cefepime (35.14%), ceftriaxone (54.30%), and aztreonam (40.29%). Piperacillin/tazobactam (1.72%) was the most effective drug against the strains, but the resistance rates increased each year. Among the isolates, 262 were identified as ESBL producers and the isolation rates for the ESBL producers increased from 63.37% to 67.35% over the four years. CTX-M (97.33%) was the most prevalent type, followed by TEM (76.72%) and SHV (3.05%). The most common ESBL genotype combination was blaTEM + blaCTX-M (74.46%), in which the frequency of carriers increased steadily, followed by blaCTX-M + blaSHV (3.05%). In addition, the most predominant specific CTX-M subtypes were CTX-M-55 (48.47%) and CTX-M-1 (17.94%), followed by CTX-M-14 (11.01%), CTX-M-15 (8.02%), CTX-M-9 (6.11%), CTX-M-65 (4.58%), and CTX-M-3 (1.15%). Moreover, a novel multiplex qPCR assay was developed to detect blaCTX-M, blaTEM, and blaSHV, with limits of detection of 2.06 × 101 copies/μL, 1.10 × 101 copies/μL, and 1.86 × 101 copies/μL, respectively, and no cross-reactivity with other ESBL genes and avian pathogens. The assays exhibited 100% sensitivity and specificities of 85%, 100%, and 100% for blaCTX-M, blaTEM, and blaSHV, respectively. In conclusion, our findings indicated that ESBL-producing E.coli strains isolated from chickens in central China were highly resistant to cephalosporins and frequently harbored diversity in ESBL-encoding genes. These isolates can pose a significant public health risk. The novel multiplex qPCR method developed in this study may be a useful tool for molecular epidemiology and surveillance studies of ESBL genes.
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9
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Li X, Zhao J, Zhang B, Duan X, Jiao J, Wu W, Zhou Y, Wang H. Drug development concerning metallo-β-lactamases in gram-negative bacteria. Front Microbiol 2022; 13:959107. [PMID: 36187949 PMCID: PMC9520474 DOI: 10.3389/fmicb.2022.959107] [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: 06/01/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
β-Lactams have been a clinical focus since their emergence and indeed act as a powerful tool to combat severe bacterial infections, but their effectiveness is threatened by drug resistance in bacteria, primarily by the production of serine- and metallo-β-lactamases. Although once of less clinical relevance, metallo-β-lactamases are now increasingly threatening. The rapid dissemination of resistance mediated by metallo-β-lactamases poses an increasing challenge to public health worldwide and comprises most existing antibacterial chemotherapies. Regrettably, there have been no clinically available inhibitors of metallo-β-lactamases until now. To cope with this unique challenge, researchers are exploring multidimensional strategies to combat metallo-β-lactamases. Several studies have been conducted to develop new drug candidates or calibrate already available drugs against metallo-β-lactamases. To provide an overview of this field and inspire more researchers to explore it further, we outline some promising candidates targeting metallo-β-lactamase producers, with a focus on Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Promising candidates in this review are composed of new antibacterial drugs, non-antibacterial drugs, antimicrobial peptides, natural products, and zinc chelators, as well as their combinations with existing antibiotics. This review may provide ideas and insight for others to explore candidate metallo-β-lactamases as well as promote the improvement of existing data to obtain further convincing evidence.
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Affiliation(s)
- Xiuyun Li
- Maternal and Child Health Development Research Center, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
| | - Jing Zhao
- Pharmaceutical Department, Shandong Provincial Taishan Hospital, Taian, China
| | - Bin Zhang
- Department of Ophthalmology, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
| | - Xuexia Duan
- Physical Examination Center, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
| | - Jin Jiao
- Department of Clinical Laboratory, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
| | - Weiwei Wu
- Department of Clinical Laboratory, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
| | - Yuxia Zhou
- Department of Clinical Laboratory, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
- *Correspondence: Yuxia Zhou
| | - Hefeng Wang
- Department of Pediatric Surgery, Shandong Provincial Maternal and Child Health Care Hospital, Jinan, China
- Hefeng Wang
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10
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Wesseling CJ, Martin NI. Synergy by Perturbing the Gram-Negative Outer Membrane: Opening the Door for Gram-Positive Specific Antibiotics. ACS Infect Dis 2022; 8:1731-1757. [PMID: 35946799 PMCID: PMC9469101 DOI: 10.1021/acsinfecdis.2c00193] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
New approaches to target antibacterial agents toward Gram-negative bacteria are key, given the rise of antibiotic resistance. Since the discovery of polymyxin B nonapeptide as a potent Gram-negative outer membrane (OM)-permeabilizing synergist in the early 1980s, a vast amount of literature on such synergists has been published. This Review addresses a range of peptide-based and small organic compounds that disrupt the OM to elicit a synergistic effect with antibiotics that are otherwise inactive toward Gram-negative bacteria, with synergy defined as a fractional inhibitory concentration index (FICI) of <0.5. Another requirement for the inclusion of the synergists here covered is their potentiation of a specific set of clinically used antibiotics: erythromycin, rifampicin, novobiocin, or vancomycin. In addition, we have focused on those synergists with reported activity against Gram-negative members of the ESKAPE family of pathogens namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and/or Acinetobacter baumannii. In cases where the FICI values were not directly reported in the primary literature but could be calculated from the published data, we have done so, allowing for more direct comparison of potency with other synergists. We also address the hemolytic activity of the various OM-disrupting synergists reported in the literature, an effect that is often downplayed but is of key importance in assessing the selectivity of such compounds for Gram-negative bacteria.
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Lopes BS, Hanafiah A, Nachimuthu R, Muthupandian S, Md Nesran ZN, Patil S. The Role of Antimicrobial Peptides as Antimicrobial and Antibiofilm Agents in Tackling the Silent Pandemic of Antimicrobial Resistance. Molecules 2022; 27:molecules27092995. [PMID: 35566343 PMCID: PMC9105241 DOI: 10.3390/molecules27092995] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/28/2022] [Accepted: 04/29/2022] [Indexed: 01/11/2023] Open
Abstract
Just over a million people died globally in 2019 due to antibiotic resistance caused by ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). The World Health Organization (WHO) also lists antibiotic-resistant Campylobacter and Helicobacter as bacteria that pose the greatest threat to human health. As it is becoming increasingly difficult to discover new antibiotics, new alternatives are needed to solve the crisis of antimicrobial resistance (AMR). Bacteria commonly found in complex communities enclosed within self-produced matrices called biofilms are difficult to eradicate and develop increased stress and antimicrobial tolerance. This review summarises the role of antimicrobial peptides (AMPs) in combating the silent pandemic of AMR and their application in clinical medicine, focusing on both the advantages and disadvantages of AMPs as antibiofilm agents. It is known that many AMPs display broad-spectrum antimicrobial activities, but in a variety of organisms AMPs are not stable (short half-life) or have some toxic side effects. Hence, it is also important to develop new AMP analogues for their potential use as drug candidates. The use of one health approach along with developing novel therapies using phages and breakthroughs in novel antimicrobial peptide synthesis can help us in tackling the problem of AMR.
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Affiliation(s)
- Bruno S. Lopes
- Department of Medical Microbiology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK
- Correspondence: (B.S.L.); (A.H.)
| | - Alfizah Hanafiah
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia;
- Correspondence: (B.S.L.); (A.H.)
| | - Ramesh Nachimuthu
- Antibiotic Resistance and Phage Therapy Laboratory, Department of Biomedical Sciences, Vellore Institute of Technology, School of Bioscience and Technology, Vellore 632014, India;
| | - Saravanan Muthupandian
- AMR and Nanotherapeutics Laboratory, Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College, Chennai 600077, India;
| | - Zarith Nameyrra Md Nesran
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur 56000, Malaysia;
| | - Sandip Patil
- Department of Hematology and Oncology, Shenzhen Children’s Hospital, Shenzhen 518038, China;
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12
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Synergistic effect and antibiofilm activity of an antimicrobial peptide with traditional antibiotics against multi-drug resistant bacteria. Microb Pathog 2021; 158:105056. [PMID: 34153416 DOI: 10.1016/j.micpath.2021.105056] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 01/10/2023]
Abstract
Combined treatment of AMPs with classical antibiotics has gained interest because it often results in a synergistic antibacterial effect. We demonstrated here that Pt5-1c, an AMP derived from phosvitin, had antibacterial activity against the MDR bacteria (S. aureus USA500, E. coli 577 and K. pneumoniae 2182) in the presence of serum. On this basis, we showed that Pt5-1c was synergistically active with traditional antibiotics (oxacillin, vancomycin, streptomycin and azithromycin) against the three MDR bacteria growing as biofilms in vitro and in vivo. Moreover, Pt5-1c restored sensitivity of S. aureus USA500 to oxacillin and vancomycin, E. coli 577 to streptomycin and K. pneumoniae 2182 to azithromycin. Importantly, long-term exposure to Pt5-1c did not give rise to antimicrobial resistance. Collectively, these data not only suggest a promising combinatorial therapy strategy to combat antibiotics-tolerant infections but also present a possibility of Pt5-1c being used to prolong the application of antibiotics including oxacillin, vancomycin, streptomycin and azithromycin, that are under threat of becoming ineffective due to antibiotic resistance.
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13
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Nowakiewicz A, Zięba P, Gnat S, Matuszewski Ł. Last Call for Replacement of Antimicrobials in Animal Production: Modern Challenges, Opportunities, and Potential Solutions. Antibiotics (Basel) 2020; 9:antibiotics9120883. [PMID: 33317032 PMCID: PMC7762978 DOI: 10.3390/antibiotics9120883] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 12/30/2022] Open
Abstract
The constant market demand for easily available and cheap food of animal origin necessitates an increasing use of antibiotics in animal production. The alarming data provided by organizations monitoring drug resistance in indicator and pathogenic bacteria isolated from humans and animals indicate a possible risk of a return to the preantibiotic era. For this reason, it seems that both preventive and therapeutic measures, taken as an alternative to antimicrobials, seem not only advisable but also necessary. Nevertheless, the results of various studies and market analyses, as well as difficulties in the implementation of alternative substances into veterinary medicine, do not guarantee that the selected alternatives will completely replace antimicrobials in veterinary medicine and animal production on a global scale. This publication is a brief overview of the drug resistance phenomenon and its determinants, the steps taken to solve the problem, including the introduction of alternatives to antimicrobials, and the evaluation of some factors influencing the potential implementation of alternatives in animal production. The review also presents two groups of alternatives, which, given their mechanism of action and spectrum, are most comparable to the effectiveness of antibiotics, as emphasized by the authors.
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Affiliation(s)
- Aneta Nowakiewicz
- Sub-Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Life Sciences, Akademicka 12, 20-033 Lublin, Poland;
- Correspondence: or
| | - Przemysław Zięba
- State Veterinary Laboratory, Droga Męczenników Majdanka 50, 20-325 Lublin, Poland;
| | - Sebastian Gnat
- Sub-Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Life Sciences, Akademicka 12, 20-033 Lublin, Poland;
| | - Łukasz Matuszewski
- Department of Pediatric Orthopedics and Rehabilitation, Faculty of Medicine, Medical University, Gębali 6, 20-093 Lublin, Poland;
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14
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Hitt SJ, Bishop BM, van Hoek ML. Komodo-dragon cathelicidin-inspired peptides are antibacterial against carbapenem-resistant Klebsiella pneumoniae. J Med Microbiol 2020; 69:1262-1272. [DOI: 10.1099/jmm.0.001260] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Introduction.The rise of carbapenem-resistant enterobacteriaceae (CRE) is a growing crisis that requires development of novel therapeutics.Hypothesis.To this end, cationic antimicrobial peptides (CAMPs) represent a possible source of new potential therapeutics to treat difficult pathogens such as carbapenem-resistantKlebsiella pneumoniae(CRKP), which has gained resistance to many if not all currently approved antibiotics, making treatment difficult.Aim.To examine the anti-CRKP antimicrobial activity of the predicted cathelicidins derived fromVaranus komodoensis(Komodo dragon) as well as synthetic antimicrobial peptides that we created.Methodology.We determined the minimum inhibitory concentrations of the peptides against CRKP. We also characterized the abilities of these peptides to disrupt the hyperpolarization of the bacterial membrane as well as their ability to form pores in the membrane.Results.We did not observe significant anti-CRKP activity for the predicted native Komodo cathelicidin peptides. We found that the novel peptides DRGN-6,-7 and -8 displayed significant antimicrobial activity against CRKP with MICs of 4–8 µg ml−1. DRGN-6 peptide was the most effective peptide against CRKP. Unfortunately, these peptides showed higher than desired levels of hemolysis, althoughin vivotesting in the waxwormGalleria mellonellashowed no mortality associated with treatment by the peptide; however, CRKP-infected waxworms treated with peptide did not show an improvement in survival.Conclusion.Given the challenges of treating CRKP, identification of peptides with activity against it represents a promising avenue for further research. Given DRGN-6′s similar level of activity to colistin, DRGN-6 is a promising template for the development of novel antimicrobial peptide-based therapeutics.
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15
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Khan DH, Bashir S, Khan MI, Figueiredo P, Santos HA, Peltonen L. Formulation optimization and in vitro characterization of rifampicin and ceftriaxone dual drug loaded niosomes with high energy probe sonication technique. J Drug Deliv Sci Technol 2020. [DOI: 10.1016/j.jddst.2020.101763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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16
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Mercer DK, Torres MDT, Duay SS, Lovie E, Simpson L, von Köckritz-Blickwede M, de la Fuente-Nunez C, O'Neil DA, Angeles-Boza AM. Antimicrobial Susceptibility Testing of Antimicrobial Peptides to Better Predict Efficacy. Front Cell Infect Microbiol 2020; 10:326. [PMID: 32733816 PMCID: PMC7358464 DOI: 10.3389/fcimb.2020.00326] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/29/2020] [Indexed: 12/11/2022] Open
Abstract
During the development of antimicrobial peptides (AMP) as potential therapeutics, antimicrobial susceptibility testing (AST) stands as an essential part of the process in identification and optimisation of candidate AMP. Standard methods for AST, developed almost 60 years ago for testing conventional antibiotics, are not necessarily fit for purpose when it comes to determining the susceptibility of microorganisms to AMP. Without careful consideration of the parameters comprising AST there is a risk of failing to identify novel antimicrobials at a time when antimicrobial resistance (AMR) is leading the planet toward a post-antibiotic era. More physiologically/clinically relevant AST will allow better determination of the preclinical activity of drug candidates and allow the identification of lead compounds. An important consideration is the efficacy of AMP in biological matrices replicating sites of infection, e.g., blood/plasma/serum, lung bronchiolar lavage fluid/sputum, urine, biofilms, etc., as this will likely be more predictive of clinical efficacy. Additionally, specific AST for different target microorganisms may help to better predict efficacy of AMP in specific infections. In this manuscript, we describe what we believe are the key considerations for AST of AMP and hope that this information can better guide the preclinical development of AMP toward becoming a new generation of urgently needed antimicrobials.
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Affiliation(s)
| | - Marcelo D. T. Torres
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Searle S. Duay
- Department of Chemistry, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
| | - Emma Lovie
- NovaBiotics Ltd, Aberdeen, United Kingdom
| | | | | | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | | | - Alfredo M. Angeles-Boza
- Department of Chemistry, Institute of Materials Science, University of Connecticut, Storrs, CT, United States
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17
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Si Z, Lim HW, Tay MYF, Du Y, Ruan L, Qiu H, Zamudio‐Vazquez R, Reghu S, Chen Y, Tiong WS, Marimuthu K, De PP, Ng OT, Zhu Y, Gan Y, Chi YR, Duan H, Bazan GC, Greenberg EP, Chan‐Park MB, Pethe K. A Glycosylated Cationic Block Poly(β‐peptide) Reverses Intrinsic Antibiotic Resistance in All ESKAPE Gram‐Negative Bacteria. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Zhangyong Si
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Hui Wen Lim
- Lee Kong Chian School of MedicineNanyang Technological University Singapore 636921 Singapore
| | - Moon Y. F. Tay
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Yu Du
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Lin Ruan
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Haofeng Qiu
- Medical School of Ningbo UniversityNingbo University Ningbo 315211 China
| | - Rubí Zamudio‐Vazquez
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Sheethal Reghu
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Yahua Chen
- Department of BiochemistryNational University of Singapore Singapore 117596 Singapore
| | - Wen Shuo Tiong
- Lee Kong Chian School of MedicineNanyang Technological University Singapore 636921 Singapore
| | - Kalisvar Marimuthu
- Tan Tock Seng Hospital Singapore 308433 Singapore
- Yong Loo Lin School of MedicineNational University of Singapore Singapore 119228 Singapore
- National Centre for Infectious Diseases Singapore
| | | | - Oon Tek Ng
- Lee Kong Chian School of MedicineNanyang Technological University Singapore 636921 Singapore
- Tan Tock Seng Hospital Singapore 308433 Singapore
- National Centre for Infectious Diseases Singapore
| | - Yabin Zhu
- Medical School of Ningbo UniversityNingbo University Ningbo 315211 China
| | - Yunn‐Hwen Gan
- Department of BiochemistryNational University of Singapore Singapore 117596 Singapore
| | - Yonggui Robin Chi
- Division of Chemistry & Biological ChemistryNanyang Technological University Singapore 637371 Singapore
| | - Hongwei Duan
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
| | - Guillermo C. Bazan
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
- Department of Chemistry and BiochemistryUniversity of California Santa Barbara CA 93106-9510 USA
| | - E. Peter Greenberg
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
- Department of MicrobiologyUniversity of Washington Seattle WA 98195 USA
| | - Mary B. Chan‐Park
- School of Chemical and Biomedical EngineeringNanyang Technological University Singapore 637459 Singapore
- Lee Kong Chian School of MedicineNanyang Technological University Singapore 636921 Singapore
| | - Kevin Pethe
- Lee Kong Chian School of MedicineNanyang Technological University Singapore 636921 Singapore
- School of Biological SciencesNanyang Technological University Singapore 637551 Singapore
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18
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Si Z, Lim HW, Tay MYF, Du Y, Ruan L, Qiu H, Zamudio-Vazquez R, Reghu S, Chen Y, Tiong WS, Marimuthu K, De PP, Ng OT, Zhu Y, Gan YH, Chi YR, Duan H, Bazan GC, Greenberg EP, Chan-Park MB, Pethe K. A Glycosylated Cationic Block Poly(β-peptide) Reverses Intrinsic Antibiotic Resistance in All ESKAPE Gram-Negative Bacteria. Angew Chem Int Ed Engl 2020; 59:6819-6826. [PMID: 32011781 DOI: 10.1002/anie.201914304] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 01/07/2020] [Indexed: 02/02/2023]
Abstract
Carbapenem-resistant Gram-negative bacteria (GNB) are heading the list of pathogens for which antibiotics are the most critically needed. Many antibiotics are either unable to penetrate the outer-membrane or are excluded by efflux mechanisms. Here, we report a cationic block β-peptide (PAS8-b-PDM12) that reverses intrinsic antibiotic resistance in GNB by two distinct mechanisms of action. PAS8-b-PDM12 does not only compromise the integrity of the bacterial outer-membrane, it also deactivates efflux pump systems by dissipating the transmembrane electrochemical potential. As a result, PAS8-b-PDM12 sensitizes carbapenem- and colistin-resistant GNB to multiple antibiotics in vitro and in vivo. The β-peptide allows the perfect alternation of cationic versus hydrophobic side chains, representing a significant improvement over previous antimicrobial α-peptides sensitizing agents. Together, our results indicate that it is technically possible for a single adjuvant to reverse innate antibiotic resistance in all pathogenic GNB of the ESKAPE group, including those resistant to last resort antibiotics.
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Affiliation(s)
- Zhangyong Si
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Hui Wen Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Moon Y F Tay
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Yu Du
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Lin Ruan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Haofeng Qiu
- Medical School of Ningbo University, Ningbo University, Ningbo, 315211, China
| | - Rubí Zamudio-Vazquez
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Sheethal Reghu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Yahua Chen
- Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore
| | - Wen Shuo Tiong
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Kalisvar Marimuthu
- Tan Tock Seng Hospital, Singapore, 308433, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 119228, Singapore.,National Centre for Infectious Diseases, Singapore
| | | | - Oon Tek Ng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore.,Tan Tock Seng Hospital, Singapore, 308433, Singapore.,National Centre for Infectious Diseases, Singapore
| | - Yabin Zhu
- Medical School of Ningbo University, Ningbo University, Ningbo, 315211, China
| | - Yunn-Hwen Gan
- Department of Biochemistry, National University of Singapore, Singapore, 117596, Singapore
| | - Yonggui Robin Chi
- Division of Chemistry & Biological Chemistry, Nanyang Technological University, Singapore, 637371, Singapore
| | - Hongwei Duan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore
| | - Guillermo C Bazan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.,Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, 93106-9510, USA
| | - E Peter Greenberg
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.,Department of Microbiology, University of Washington, Seattle, WA, 98195, USA
| | - Mary B Chan-Park
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 637459, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Kevin Pethe
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
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19
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Antimicrobial Activity of Protein Fraction from Naja ashei Venom Against Staphylococcus epidermidis. Molecules 2020; 25:molecules25020293. [PMID: 31936872 PMCID: PMC7024148 DOI: 10.3390/molecules25020293] [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: 12/04/2019] [Revised: 01/04/2020] [Accepted: 01/08/2020] [Indexed: 01/10/2023] Open
Abstract
One of the key problems of modern infectious disease medicine is the growing number of drug-resistant and multi-drug-resistant bacterial strains. For this reason, many studies are devoted to the search for highly active antimicrobial substances that could be used in therapy against bacterial infections. As it turns out, snake venoms are a rich source of proteins that exert a strong antibacterial effect, and therefore they have become an interesting research material. We analyzed Naja ashei venom for such antibacterial properties, and we found that a specific composition of proteins can act to eliminate individual bacterial cells, as well as the entire biofilm of Staphylococcus epidermidis. In general, we used ion exchange chromatography (IEX) to obtain 10 protein fractions with different levels of complexity, which were then tested against certified and clinical strains of S. epidermidis. One of the fractions (F2) showed exceptional antimicrobial effects both alone and in combination with antibiotics. The protein composition of the obtained fractions was determined using mass spectrometry techniques, indicating a high proportion of phospholipases A2, three-finger toxins, and L-amino acids oxidases in F2 fraction, which are most likely responsible for the unique properties of this fraction. Moreover, we were able to identify a new group of low abundant proteins containing the Ig-like domain that have not been previously described in snake venoms.
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20
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Coates ARM, Hu Y, Holt J, Yeh P. Antibiotic combination therapy against resistant bacterial infections: synergy, rejuvenation and resistance reduction. Expert Rev Anti Infect Ther 2020; 18:5-15. [DOI: 10.1080/14787210.2020.1705155] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Anthony R. M. Coates
- Institute of Infection and Immunity, St George’s, University of London, London, UK
| | - Yanmin Hu
- Institute of Infection and Immunity, St George’s, University of London, London, UK
| | - James Holt
- Division of Infection and Immunity, University College London, London, UK
| | - Pamela Yeh
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
- Santa Fe Institute, Santa Fe, NM, USA
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21
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Amison RT, Faure ME, O'Shaughnessy BG, Bruce KD, Hu Y, Coates A, Page CP. The small quinolone derived compound HT61 enhances the effect of tobramycin against Pseudomonas aeruginosa in vitro and in vivo. Pulm Pharmacol Ther 2019; 61:101884. [PMID: 31887372 DOI: 10.1016/j.pupt.2019.101884] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 11/26/2022]
Abstract
HT61 is a small quinolone-derived compound previously demonstrated to exhibit bactericidal activity against gram-positive bacteria including methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA). When combined with the classical antibiotics and antiseptics neomycin, gentamicin, mupirocin and chlorhexidine, HT61 demonstrated synergistic bactericidal activity against both MSSA and MRSA infections in vitro. In this study, we investigated the individual antimicrobial activity of HT61 alongside its capability to potentiate the efficacy of tobramycin against both a tobramycin sensitive laboratory reference strain (PAO1) and tobramycin resistant clinical isolates (RP73, NN2) of the gram-negative bacteria Pseudomonas aeruginosa (P. aeruginosa). Using broth microdilution methods, the MICs of HT61 were assessed against all strains, as well as the effect of HT61 in combination with tobramycin using both the chequerboard method and bacterial time-kill assays. A murine model of pulmonary infection was also used to evaluate the combination therapy of tobramycin and HT61 in vivo. In these studies, we demonstrated significant synergism between HT61 and tobramycin against the tobramycin resistant P. aeruginosa strains RP73 and NN2, whilst an additive/intermediate effect was observed for P. aeruginosa strain PA01 which was further confirmed using bacterial time kill analysis. In addition, the enhancement of tobramycin by HT61 was also evident in in vitro assays of biofilm eradication. Finally, in vivo studies revealed analogous effects to those observed in vitro with HT61 significantly reducing bacterial load when administered in combination with tobramycin against each of the three P. aeruginosa strains at the highest tested dose (10 mg/kg).
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Affiliation(s)
- R T Amison
- Sackler Institute of Pulmonary Pharmacology, School of Cancer and Pharmaceutical Sciences, King's College London, London, SE1 9NH, UK.
| | - M-E Faure
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE1 9NH, UK
| | - B G O'Shaughnessy
- Sackler Institute of Pulmonary Pharmacology, School of Cancer and Pharmaceutical Sciences, King's College London, London, SE1 9NH, UK
| | - K D Bruce
- School of Cancer and Pharmaceutical Sciences, King's College London, London, SE1 9NH, UK
| | - Y Hu
- Institute of Infection and Immunity, St George's, University of London, Cranmer Terrace, London, SW17 ORE, UK
| | - A Coates
- Institute of Infection and Immunity, St George's, University of London, Cranmer Terrace, London, SW17 ORE, UK
| | - C P Page
- Sackler Institute of Pulmonary Pharmacology, School of Cancer and Pharmaceutical Sciences, King's College London, London, SE1 9NH, UK
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22
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Shang D, Liu Y, Jiang F, Ji F, Wang H, Han X. Synergistic Antibacterial Activity of Designed Trp-Containing Antibacterial Peptides in Combination With Antibiotics Against Multidrug-Resistant Staphylococcus epidermidis. Front Microbiol 2019; 10:2719. [PMID: 31824473 PMCID: PMC6886405 DOI: 10.3389/fmicb.2019.02719] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 11/08/2019] [Indexed: 01/10/2023] Open
Abstract
Multidrug resistance among various bacterial strains is leading to worldwide resistance to a wide range of antibiotics. Combination therapy involving current antibiotics and other biological or chemical molecules represents an attractive novel strategy. In this study, we investigated the synergistic antibacterial activity of a series of Trp-containing antimicrobial peptides (AMPs) with four classes of traditional chemical antibiotics that are inactive against multidrug-resistant Staphylococcus epidermidis (MRSE) in vitro and in vivo. Among the antibiotics that we studied, penicillin, ampicillin and erythromycin showed a distinct synergistic effect in combination with all of the Trp-containing AMPs, represented by a fractional inhibitory concentration index (FICI) of <0.5. The antibacterial activities were noticeably improved, with 32-to 64-fold reductions in the MIC values for ampicillin and 16- to 32-fold reductions in the MIC values for erythromycin and penicillin. Tetracycline showed synergistic activity with only I1WL5W but additive activity with L11W, L12W, and I4WL5W. Ceftazidime exhibited additive activity with the Trp-containing peptides. In addition, the antibiotics in combination with the peptide significantly inhibited biofilm formation by MRSE 1208. A mechanistic study demonstrated that the Trp-containing peptides, especially I1WL5W and I4WL5W, which contain two tryptophan residues, disrupted bacterial inner and outer membranes, which promoted antibiotic delivery into the cytoplasm and access to cytoplasmic targets; however, L11W and L12W may have increased intracellular antibiotic concentrations by decreasing blaZ, tet(m) and msrA expression. Importantly, strong synergistic activity against the MRSE 1208 strain was observed for the combination of I1WL5W and penicillin in a mouse infection model. Thus, the combination of AMPs and traditional antibiotics could be a promising option for the prevention of acute and chronic infections caused by MRSE.
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Affiliation(s)
- Dejing Shang
- School of Life Sciences, Liaoning Normal University, Dalian, China.,Liaoning Provincial Key Laboratory of Biotechnology and Drug Discovery, Liaoning Normal University, Dalian, China
| | - Yue Liu
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - Fengquan Jiang
- School of Life Sciences, Liaoning Normal University, Dalian, China.,Clinical Laboratory Department of the First Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Fangyu Ji
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - He Wang
- School of Life Sciences, Liaoning Normal University, Dalian, China
| | - Xue Han
- School of Life Sciences, Liaoning Normal University, Dalian, China
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Rattanapanadda P, Kuo HC, Vickroy TW, Sung CH, Rairat T, Lin TL, Yeh SY, Chou CC. In vitro and in vivo Synergistic Effects of Florfenicol and Thiamphenicol in Combination Against Swine Actinobacillus pleuropneumoniae and Pasteurella multocida. Front Microbiol 2019; 10:2430. [PMID: 31749775 PMCID: PMC6842999 DOI: 10.3389/fmicb.2019.02430] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/08/2019] [Indexed: 12/16/2022] Open
Abstract
Potential synergism between florfenicol (FF) and thiamphenicol (TAP) was investigated for in vitro efficacy against Actinobacillus pleuropneumoniae and/or Pasteurella multocida as well as in vivo efficacy in swine. Among isolates of A. pleuropneumoniae (n = 58) and P. multocida (n = 79) from pigs in Taiwan that were tested, high percentages showed resistance to FF (52 and 53%, respectively) and TAP (57 and 53%, respectively). Checkerboard microdilution assay indicated that synergism [fractional inhibitory concentration index (FICI) ≤ 0.5] was detected in 17% of A. pleuropneumoniae (all serovar 1) and 24% of P. multocida isolates. After reconfirming the strains showing FICI ≤ 0.625 with time kill assay, the synergism increased to around 32% against both bacteria and the number could further increase to 40% against resistant A. pleuropneumoniae and 65% against susceptible P. multocida isolates. A challenge-treatment trial in pigs with P. multocida showed that the FF + TAP dosage at ratios correspondent to their MIC deduction was equally effective to the recommended dosages. Further on the combination, the resistant mutation frequency is very low when A. pleuropneumoniae is grown with FF + TAP and similar to the exposure to sub-inhibitory concentration of FF or TAP alone. The degree of minimum inhibitory concentration (MIC) reduction in FF could reach 75% (1/4 MIC) or more (up to 1/8 MIC for P. multocida, 1/16 for A. pleuropneumoniae) when combined with 1/4 MIC of TAP (or 1/8 for A. pleuropneumoniae). The synergism or FICI ≤ 0.625 of FF with oxytetracycline (47%), doxycycline (69%), and erythromycin (56%) was also evident, and worth further investigation for FF as a central modulator facilitating synergistic effects with these antimicrobials. Taken together, synergistic FF + TAP combination was effective against swine pulmonary isolates of A. pleuropneumoniae and P. multocida both in vitro and in vivo. Thus, this study may offer a potential alternative for the treatment of A. pleuropneumoniae and P. multocida infections and has the potential to greatly reduce drug residues and withdrawal time.
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Affiliation(s)
- Porjai Rattanapanadda
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Hung-Chih Kuo
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chiayi University, Chiayi, Taiwan
| | - Thomas W. Vickroy
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Chi-Hsuan Sung
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Tirawat Rairat
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Tsai-Lu Lin
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Sze-Yu Yeh
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Chi-Chung Chou
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
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24
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A Pilot Study of the Synergy between Two Antimicrobial Peptides and Two Common Antibiotics. Antibiotics (Basel) 2019; 8:antibiotics8020060. [PMID: 31075940 PMCID: PMC6627861 DOI: 10.3390/antibiotics8020060] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/17/2019] [Accepted: 05/05/2019] [Indexed: 11/16/2022] Open
Abstract
Background: Frequent and unrestricted use of antibiotics has been associated with the development of antibiotic resistance by microorganisms. Thus, there is a need to find novel antibacterial agents or a combination of agents as the first line of treatment for various infections. This study aimed to investigate the synergy between antimicrobial peptide (AMP) combinations or between AMP-antibiotics combinations using two common pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Methods: The AMPs melimine, Mel4 and protamine, and antibiotics cefepime and ciprofloxacin were used in this study. The minimum inhibitory concentration (MIC) of each were evaluated against P. aeruginosa and S. aureus strains by a microtiter broth dilution. Based on the MIC of each antimicrobial agent, a checkerboard assay was performed to investigate the synergy between them, which was expressed as the fractional inhibitory concentration (FIC). Results: The combination of melimine and ciprofloxacin showed synergistic activity against antibiotic sensitive or resistant strains of P. aeruginosa and with FIC values ≤0.5. Conclusion: Combinations of AMPs and the fluoroquinolone ciprofloxacin is a promising method for reducing resistance to the fluoroquinolone of P. aeruginosa.
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25
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Zharkova MS, Orlov DS, Golubeva OY, Chakchir OB, Eliseev IE, Grinchuk TM, Shamova OV. Application of Antimicrobial Peptides of the Innate Immune System in Combination With Conventional Antibiotics-A Novel Way to Combat Antibiotic Resistance? Front Cell Infect Microbiol 2019; 9:128. [PMID: 31114762 PMCID: PMC6503114 DOI: 10.3389/fcimb.2019.00128] [Citation(s) in RCA: 153] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 04/10/2019] [Indexed: 01/10/2023] Open
Abstract
Rapidly growing resistance of pathogenic bacteria to conventional antibiotics leads to inefficiency of traditional approaches of countering infections and determines the urgent need for a search of fundamentally new anti-infective drugs. Antimicrobial peptides (AMPs) of the innate immune system are promising candidates for a role of such novel antibiotics. However, some cytotoxicity of AMPs toward host cells limits their active implementation in medicine and forces attempts to design numerous structural analogs of the peptides with optimized properties. An alternative route for the successful AMPs introduction may be their usage in combination with conventional antibiotics. Synergistic antibacterial effects have been reported for a number of such combinations, however, the molecular mechanisms of the synergy remain poorly understood and little is known whether AMPs cytotoxicy for the host cells increases upon their application with antibiotics. Our study is directed to examination of a combined action of natural AMPs with different structure and mode of action (porcine protegrin 1, caprine bactenecin ChBac3.4, human alpha- and beta-defensins (HNP-1, HNP-4, hBD-2, hBD-3), human cathelicidin LL-37), and egg white lysozyme with varied antibiotic agents (gentamicin, ofloxacin, oxacillin, rifampicin, polymyxin B, silver nanoparticles) toward selected bacteria, including drug-sensitive and drug-resistant strains, as well as toward some mammalian cells (human erythrocytes, PBMC, neutrophils, murine peritoneal macrophages and Ehrlich ascites carcinoma cells). Using “checkerboard titrations” for fractional inhibitory concentration indexes evaluation, it was found that synergy in antibacterial action mainly occurs between highly membrane-active AMPs (e.g., protegrin 1, hBD-3) and antibiotics with intracellular targets (e.g., gentamicin, rifampcin), suggesting bioavailability increase as the main model of such interaction. In some combinations modulation of dynamics of AMP-bacterial membrane interaction in presence of the antibiotic was also shown. Cytotoxic effects of the same combinations toward normal eukaryotic cells were rarely synergistic. The obtained data approve that combined application of antimicrobial peptides with antibiotics or other antimicrobials is a promising strategy for further development of new approach for combating antibiotic-resistant bacteria by usage of AMP-based therapeutics. Revealing the conventional antibiotics that increase the activity of human endogenous AMPs against particular pathogens is also important for cure strategies elaboration.
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Affiliation(s)
- Maria S Zharkova
- Laboratory of Design and Synthesis of Biologically Active Peptides, Department of General Pathology and Pathophysiology, FSBSI Institute of Experimental Medicine, Saint Petersburg, Russia
| | - Dmitriy S Orlov
- Laboratory of Design and Synthesis of Biologically Active Peptides, Department of General Pathology and Pathophysiology, FSBSI Institute of Experimental Medicine, Saint Petersburg, Russia
| | - Olga Yu Golubeva
- Laboratory of Nanostructures Research, Institute of Silicate Chemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Oleg B Chakchir
- Nanobiotechnology Laboratory, Saint Petersburg National Research Academic University of the Russian Academy of Science, Saint Petersburg, Russia
| | - Igor E Eliseev
- Nanobiotechnology Laboratory, Saint Petersburg National Research Academic University of the Russian Academy of Science, Saint Petersburg, Russia
| | - Tatyana M Grinchuk
- Laboratory of Intracellular Signaling, Institute of Cytology of the Russian Academy of Science, Saint Petersburg, Russia
| | - Olga V Shamova
- Laboratory of Design and Synthesis of Biologically Active Peptides, Department of General Pathology and Pathophysiology, FSBSI Institute of Experimental Medicine, Saint Petersburg, Russia
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26
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Azidothymidine Produces Synergistic Activity in Combination with Colistin against Antibiotic-Resistant Enterobacteriaceae. Antimicrob Agents Chemother 2018; 63:AAC.01630-18. [PMID: 30373798 DOI: 10.1128/aac.01630-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/12/2018] [Indexed: 12/21/2022] Open
Abstract
Bacterial infections remain a leading killer worldwide, which is worsened by the continuous emergence of antibiotic resistance. In particular, antibiotic-resistant Enterobacteriaceae are prevalent and extremely difficult to treat. Repurposing existing drugs and improving the therapeutic potential of existing antibiotics represent an attractive novel strategy. Azidothymidine (AZT) is an antiretroviral drug which is used in combination with other antivirals to prevent and to treat HIV/AIDS. AZT is also active against Gram-negative bacteria but has not been developed for that purpose. Here, we investigated the in vitro and in vivo efficacy of AZT in combination with colistin against antibiotic-resistant Enterobacteriaceae, including strains producing extended-spectrum beta-lactamases (ESBLs) or New Delhi metallo-beta-lactamase 1 (NDM) or carrying mobilized colistin resistance (mcr-1). The MIC was determined using the broth microdilution method. The combined effect of AZT and colistin was examined using the checkerboard method and time-kill analysis. A murine peritoneal infection model was used to test the therapeutic effect of the combination of AZT and colistin. The fractional inhibitory concentration index from the checkerboard assay demonstrated that AZT synergized with colistin against 61% and 87% of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains, respectively, 100% of NDM-1-producing strains, and 92% of mcr-1-producing E. coli strains. Time-kill analysis demonstrated significant synergistic activities when AZT was combined with colistin. In a murine peritoneal infection model, AZT in combination with colistin showed augmented activities of both drugs in the treatment of NDM-1 K. pneumoniae and mcr-1 E. coli infections. The AZT and colistin combination possesses a potential to be used coherently to treat antibiotic-resistant Enterobacteriaceae infections.
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27
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Domalaon R, Brizuela M, Eisner B, Findlay B, Zhanel GG, Schweizer F. Dilipid ultrashort cationic lipopeptides as adjuvants for chloramphenicol and other conventional antibiotics against Gram-negative bacteria. Amino Acids 2018; 51:383-393. [PMID: 30392097 DOI: 10.1007/s00726-018-2673-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 10/25/2018] [Indexed: 02/02/2023]
Abstract
The necessity to develop therapeutic agents and strategies to abate the spread of antibiotic-resistant pathogens is prominent. Antimicrobial peptides (AMPs) provide scaffolds and inspiration for antibiotic development. As an AMP of shorter scaffold, eight dilipid ultrashort cationic lipopeptides (dUSCLs) were prepared consisting of only four amino acids and varying dilipids. Lipids were acylated at the peptide N-terminus and the ε-amine side chain of the N-terminal L-lysine. Compounds that possess aliphatic dilipids of ≥ 11 carbons-long showed significant hemolysis and therefore limited therapeutic application. Several non-hemolytic dUSCLs were identified to enhance the activity of chloramphenicol and other conventional antibiotics against Gram-negative bacteria. Compounds 2 and 6 have a short peptide sequence of KKKK and KKGK, respectively, and are both acylated with an aliphatic dilipid of nine carbons-long potentiated chloramphenicol against MDR clinical isolates of Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae. Both dUSCLs showed comparable adjuvant potency in combination with chloramphenicol. However, dUSCL 2 synergized with a wider span of antibiotic classes against P. aeruginosa relative to dUSCL 6 that included rifampicin, trimethoprim, minocycline, fosfomycin, piperacillin, ciprofloxacin, levofloxacin, moxifloxacin, linezolid and vancomycin. Our data revealed that dUSCLs can indirectly disrupt active efflux of chloramphenicol in P. aeruginosa. This along with their membrane-permeabilizing properties may explain the dUSCLs synergistic combination with conventional antibiotics against Gram-negative bacteria.
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Affiliation(s)
- Ronald Domalaon
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Marc Brizuela
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Benjamin Eisner
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Brandon Findlay
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - George G Zhanel
- Department of Medical Microbiology & Infectious Diseases, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada
| | - Frank Schweizer
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada. .,Department of Medical Microbiology & Infectious Diseases, University of Manitoba, Winnipeg, MB, R3E 0J9, Canada.
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28
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Milosavljevic V, Haddad Y, Moulick A, Buchtelova H, Guran R, Pospisil T, Stokowa-Sołtys K, Heger Z, Richtera L, Kopel P, Adam V. Functional Analysis of Novicidin Peptide: Coordinated Delivery System for Zinc via Schiff Base Ligand. Bioconjug Chem 2018; 29:2954-2969. [PMID: 30086240 DOI: 10.1021/acs.bioconjchem.8b00370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Novicidin (NVC), is a membrane-penetrating peptide, which forms a stable complex with Zn-Schiff base with interesting antitumor selectivity. We studied NVC derivatives to determine functional roles of key amino acids in toxicity, helicity, and binding of the Zn-Schiff base complex. Trimmed derivatives highlighted the role of peptide length and helicity in toxicity and membrane penetration. The removal of Lys from position 1 and 2 strongly increases the ability to disrupt the membranes. The trimming of the N-terminal residues significantly increases the stability of peptide helicity enhancing penetrating properties. Gly residue derivatives undermined a role of peptide bending in membrane penetration and toxicity. After the substitution of the central Gly derivatives with Ile or Lys, the peptides retained toxicity. These results illustrate the minor role of central helix bending in NVC toxicity. Binding-site-peptide derivatives identified His residue as the sole Zn-Schiff base binding site and eliminated the role of other aromatic residues.
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Affiliation(s)
- Vedran Milosavljevic
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Yazan Haddad
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Amitava Moulick
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Hana Buchtelova
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Roman Guran
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Tomas Pospisil
- Department of Chemical Biology and Genetics, Centre of the Region Hana for Biotechnological and Agricultural Research , Faculty of Science, Palacky University , Slechtitelu 241/27 , 783 71 , Olomouc , Czech Republic
| | - Kamila Stokowa-Sołtys
- Faculty of Chemistry , University of Wrocław , Joliot-Curie 14 , 50-383 Wrocław , Poland
| | - Zbynek Heger
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Lukas Richtera
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Pavel Kopel
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
| | - Vojtech Adam
- Central European Institute of Technology , Brno University of Technology , Purkynova 123 , 612 00 Brno , Czech Republic.,Department of Chemistry and Biochemistry , Mendel University in Brno , Zemedelska 1 , 613 00 Brno , Czech Republic
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29
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Li Z, Hu Y, Yang Y, Lu Z, Wang Y. Antimicrobial resistance in livestock: antimicrobial peptides provide a new solution for a growing challenge. Anim Front 2018; 8:21-29. [PMID: 32002215 PMCID: PMC6951932 DOI: 10.1093/af/vfy005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Zhi Li
- Laboratory of Animal Nutrition and Feed Science, Department of Animal Science, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Yuhan Hu
- Laboratory of Animal Nutrition and Feed Science, Department of Animal Science, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Yuanyuan Yang
- Laboratory of Animal Nutrition and Feed Science, Department of Animal Science, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Zeqing Lu
- Laboratory of Animal Nutrition and Feed Science, Department of Animal Science, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Yizhen Wang
- Laboratory of Animal Nutrition and Feed Science, Department of Animal Science, Zhejiang University, Hangzhou, Zhejiang Province, China
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30
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Jindal HM, Zandi K, Ong KC, Velayuthan RD, Rasid SM, Samudi Raju C, Sekaran SD. Mechanisms of action and in vivo antibacterial efficacy assessment of five novel hybrid peptides derived from Indolicidin and Ranalexin against Streptococcus pneumoniae. PeerJ 2017; 5:e3887. [PMID: 29018620 PMCID: PMC5632533 DOI: 10.7717/peerj.3887] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/13/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Antimicrobial peptides (AMPs) are of great potential as novel antibiotics for the treatment of broad spectrum of pathogenic microorganisms including resistant bacteria. In this study, the mechanisms of action and the therapeutic efficacy of the hybrid peptides were examined. METHODS TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel. In vitro synergistic effect was checked using the chequerboard assay. ICR male mice were used to evaluate the in vivo toxicity and antibacterial activity of the hybrid peptides in a standalone form and in combination with ceftriaxone. RESULTS The results obtained from TEM and SEM indicated that the hybrid peptides caused significant morphological alterations in Streptococcus pneumoniae and disrupting the integrity of the cell wall/membrane. The rapid release of ATP from pneumococcal cells after one hour of incubation proposing that the antibacterial action for the hybrid peptides is based on membrane permeabilization and damage. The DNA retardation assay revealed that at 62.5 µg/ml all the hybrid peptides were capable of binding and preventing the pneumococcal genomic DNA from migrating through the agarose gel. In vitro synergy was observed when pneumococcal cells treated with combinations of hybrid peptides with each other and with conventional drugs erythromycin and ceftriaxone. The in vivo therapeutic efficacy results revealed that the hybrid peptide RN7-IN8 at 20 mg/kg could improve the survival rate of pneumococcal bacteremia infected mice, as 50% of the infected mice survived up to seven days post-infection. In vivo antibacterial efficacy of the hybrid peptide RN7-IN8 was signficantly improved when combined with the standard antibiotic ceftriaxone at (20 mg/kg + 20 mg/kg) as 100% of the infected mice survived up to seven days post-infection. DISCUSSION Our results suggest that attacking and breaching the cell wall/membrane is most probably the principal mechanism for the hybrid peptides. In addition, the hybrid peptides could possess another mechanism of action by inhibiting intracellular functions such as DNA synthesis. AMPs could play a great role in combating antibiotic resistance as they can reduce the therapeutic concentrations of standard drugs.
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Affiliation(s)
- Hassan Mahmood Jindal
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Keivan Zandi
- Department of Pediatrics, School of Medicine, Emory University, Atlanta, United States of America
| | - Kien Chai Ong
- Department of Biomedical Science, Faculty of Medicine, University Malaya, Malaysia
| | - Rukumani Devi Velayuthan
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sara Maisha Rasid
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Chandramathi Samudi Raju
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Shamala Devi Sekaran
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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31
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Pollini S, Brunetti J, Sennati S, Rossolini GM, Bracci L, Pini A, Falciani C. Synergistic activity profile of an antimicrobial peptide against multidrug-resistant and extensively drug-resistant strains of Gram-negative bacterial pathogens. J Pept Sci 2017; 23:329-333. [PMID: 28176481 DOI: 10.1002/psc.2978] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 12/22/2022]
Abstract
Infection sustained by multidrug-resistant and extensively drug-resistant bacterial pathogens is often untreatable with the standard of care antibiotics, and the combination of anti-infective compounds often represents the only therapeutic strategy to face this major clinical treat. SET-M33 is a novel antimicrobial peptide (AMP) that has demonstrated in vitro and in vivo antimicrobial activity against Gram-negative bacteria and has shown interesting features in preclinical evaluations. Particularly, it showed efficacy against a number of multidrug-resistant and extensively drug-resistant clinical strains of Gram-negative pathogens, in in vitro and in vivo assessments. Here, we explored the potential synergistic activity of SET-M33 in combination with different standard of care antibiotics by the checkerboard method against a panel of six strains of Gram-negative pathogens including multidrug-resistant and extensively drug-resistant Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. SET-M33 showed synergistic activity with antibiotics of different families against these clinically relevant strains. A synergistic effect was observed for SET-M33 in combination with rifampin, meropenem, aztreonam, and tobramycin mostly on K. pneumoniae and A. baumannii strains, while the SET-M33 plus ciprofloxacin combination was additive with all tested strains. Synergy was not apparently linked to the bacterial species or phenotype but was rather strain-specific, highlighting the need for individual strain testing for synergistic antimicrobial combinations. These findings extend current knowledge on synergistic activity of AMPs in combination with conventional agents and support the potential role of SET-M33 as a novel therapeutic agent against antibiotic-resistant Gram-negative pathogens. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
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Affiliation(s)
- Simona Pollini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy.,Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - Jlenia Brunetti
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Samanta Sennati
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy.,Clinical Microbiology and Virology Unit, Careggi University Hospital, Florence, Italy.,Don Carlo Gnocchi Foundation, Florence, Italy
| | - Luisa Bracci
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Alessandro Pini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Chiara Falciani
- Department of Medical Biotechnologies, University of Siena, Siena, Italy.,Setlance srl, Siena, Italy
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32
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Memariani H, Shahbazzadeh D, Ranjbar R, Behdani M, Memariani M, Pooshang Bagheri K. Design and characterization of short hybrid antimicrobial peptides from pEM-2, mastoparan-VT1, and mastoparan-B. Chem Biol Drug Des 2016; 89:327-338. [PMID: 27591703 DOI: 10.1111/cbdd.12864] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 07/12/2016] [Accepted: 08/06/2016] [Indexed: 02/01/2023]
Abstract
Antimicrobial peptides are considered to be excellent templates for designing novel antibiotics because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance. In this study, for the first time, a series of short hybrid antimicrobial peptides combined by different fragments of venom-derived alpha-helical antimicrobial peptides pEM-2, mastoparan-VT1, and mastoparan-B were designed with the intent to improve the therapeutic index of the parental peptides. Short hybrid antimicrobial peptides PV, derived from pEM-2 and mastoparan-VT1, was found to possess the highest antibacterial, hemolytic, and cytotoxic activity. Short hybrid antimicrobial peptides PV3, derived from pEM-2 and three fragments of mastoparan-VT1, showed more than threefold improvement in therapeutic index compared with parental peptides pEM-2 and mastoparan-VT1. PV had the highest antimicrobial activity in stability studies. Except BVP, designed based on all three parental peptides, the other short hybrid antimicrobial peptides at their minimal inhibitory concentration and 2× minimal inhibitory concentration required less than 120 and 60 min to reduce >3log10 the initial inoculum, respectively. All peptides had membrane-disrupting activity in a time-dependent manner. Collectively, this study highlights the potential for rational design of improved short hybrid antimicrobial peptides such as PV3 that was an ideal candidate for further assessment with the ultimate purpose of development of effective antimicrobial agents.
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Affiliation(s)
- Hamed Memariani
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Delavar Shahbazzadeh
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Reza Ranjbar
- Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mahdi Behdani
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mojtaba Memariani
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Kamran Pooshang Bagheri
- Venom and Biotherapeutics Molecules Laboratory, Medical Biotechnology Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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33
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Efficacy of Linezolid and Fosfomycin in Catheter-Related Biofilm Infection Caused by Methicillin-Resistant Staphylococcus aureus. BIOMED RESEARCH INTERNATIONAL 2016; 2016:6413982. [PMID: 27366751 PMCID: PMC4913002 DOI: 10.1155/2016/6413982] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/04/2016] [Accepted: 05/10/2016] [Indexed: 01/24/2023]
Abstract
As long-standing clinical problems, catheter-related infections and other chronic biofilm infections are more difficult to treat due to the high antibiotic resistance of biofilm. Therefore, new treatments are needed for more effective bacteria clearance. In this study, we evaluated the antibacterial activities of several common antibiotics alone and their combinations against biofilm-embedded methicillin-resistant staphylococcus aureus (MRSA) infections, both in vitro and in vivo. In brief, fosfomycin, levofloxacin, and rifampin alone or in combination with linezolid were tested in vitro against planktonic and biofilm-embedded MRSA infection in three MRSA stains. The synergistic effects between linezolid and the other three antibiotics were assessed by fractional inhibitory concentration index (FICI) and time-kill curves, where the combination of linezolid plus fosfomycin showed the best synergistic effect in all strains. For further evaluation in vivo, we applied the combination of linezolid and fosfomycin in a catheter-related biofilm rat model and found that viable bacteria counts in biofilm were significantly reduced after treatment (P < 0.05). In summary, we have shown here that the combination of linezolid and fosfomycin treatment had improved therapeutic effects on biofilm-embedded MRSA infection both in vitro and in vivo, which provided important basis for new clinical therapy development.
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Czaplewski L, Bax R, Clokie M, Dawson M, Fairhead H, Fischetti VA, Foster S, Gilmore BF, Hancock REW, Harper D, Henderson IR, Hilpert K, Jones BV, Kadioglu A, Knowles D, Ólafsdóttir S, Payne D, Projan S, Shaunak S, Silverman J, Thomas CM, Trust TJ, Warn P, Rex JH. Alternatives to antibiotics-a pipeline portfolio review. THE LANCET. INFECTIOUS DISEASES 2016; 16:239-51. [PMID: 26795692 DOI: 10.1016/s1473-3099(15)00466-1] [Citation(s) in RCA: 533] [Impact Index Per Article: 66.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 11/06/2015] [Accepted: 11/10/2015] [Indexed: 01/21/2023]
Abstract
Antibiotics have saved countless lives and enabled the development of modern medicine over the past 70 years. However, it is clear that the success of antibiotics might only have been temporary and we now expect a long-term and perhaps never-ending challenge to find new therapies to combat antibiotic-resistant bacteria. A broader approach to address bacterial infection is needed. In this Review, we discuss alternatives to antibiotics, which we defined as non-compound approaches (products other than classic antibacterial agents) that target bacteria or any approaches that target the host. The most advanced approaches are antibodies, probiotics, and vaccines in phase 2 and phase 3 trials. This first wave of alternatives to antibiotics will probably best serve as adjunctive or preventive therapies, which suggests that conventional antibiotics are still needed. Funding of more than £1·5 billion is needed over 10 years to test and develop these alternatives to antibiotics. Investment needs to be partnered with translational expertise and targeted to support the validation of these approaches in phase 2 trials, which would be a catalyst for active engagement and investment by the pharmaceutical and biotechnology industry. Only a sustained, concerted, and coordinated international effort will provide the solutions needed for the future.
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Affiliation(s)
- Lloyd Czaplewski
- Chemical Biology Ventures, Abingdon, Oxfordshire, UK; Abgentis, Edgbaston, Birmingham, UK; Persica Pharmaceuticals, Canterbury, Kent, UK.
| | | | - Martha Clokie
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester, UK
| | - Mike Dawson
- Novacta Biosystems, Welwyn Garden City, Hertfordshire, UK; Cantab Anti-infectives, Welwyn Garden City, Hertfordshire, UK
| | | | - Vincent A Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, New York, NY, USA
| | - Simon Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK; Absynth Biologics, Liverpool, UK
| | | | - Robert E W Hancock
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - David Harper
- Evolution Biotechnologies, Ampthill, Bedfordshire, UK
| | - Ian R Henderson
- Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, UK
| | - Kai Hilpert
- Institute of Infection and Immunity, St George's, University of London, London, UK; TiKa Diagnostics, London, UK
| | - Brian V Jones
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK; Queen Victoria Hospital NHS Foundation Trust, East Grinstead, West Sussex, UK
| | - Aras Kadioglu
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
| | - David Knowles
- Absynth Biologics, Liverpool, UK; Procarta Biosystems, Norwich, UK
| | | | - David Payne
- GlaxoSmithKline, Collegeville, Pennsylvania, PA, USA
| | | | - Sunil Shaunak
- Department of Medicine, Imperial College London, London, UK
| | | | - Christopher M Thomas
- Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham, UK; Plasgene, Edgbaston, Birmingham, UK
| | - Trevor J Trust
- Pan-Provincial Vaccine Enterprise, Saskatoon, SK, Canada
| | | | - John H Rex
- AstraZeneca, Boston, MA, USA; F2G, Manchester, UK
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