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Evseev PV, Sukhova AS, Tkachenko NA, Skryabin YP, Popova AV. Lytic Capsule-Specific Acinetobacter Bacteriophages Encoding Polysaccharide-Degrading Enzymes. Viruses 2024; 16:771. [PMID: 38793652 PMCID: PMC11126041 DOI: 10.3390/v16050771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/09/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
The genus Acinetobacter comprises both environmental and clinically relevant species associated with hospital-acquired infections. Among them, Acinetobacter baumannii is a critical priority bacterial pathogen, for which the research and development of new strategies for antimicrobial treatment are urgently needed. Acinetobacter spp. produce a variety of structurally diverse capsular polysaccharides (CPSs), which surround the bacterial cells with a thick protective layer. These surface structures are primary receptors for capsule-specific bacteriophages, that is, phages carrying tailspikes with CPS-depolymerizing/modifying activities. Phage tailspike proteins (TSPs) exhibit hydrolase, lyase, or esterase activities toward the corresponding CPSs of a certain structure. In this study, the data on all lytic capsule-specific phages infecting Acinetobacter spp. with genomes deposited in the NCBI GenBank database by January 2024 were summarized. Among the 149 identified TSPs encoded in the genomes of 143 phages, the capsular specificity (K specificity) of 46 proteins has been experimentally determined or predicted previously. The specificity of 63 TSPs toward CPSs, produced by various Acinetobacter K types, was predicted in this study using a bioinformatic analysis. A comprehensive phylogenetic analysis confirmed the prediction and revealed the possibility of the genetic exchange of gene regions corresponding to the CPS-recognizing/degrading parts of different TSPs between morphologically and taxonomically distant groups of capsule-specific Acinetobacter phages.
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Affiliation(s)
- Peter V. Evseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia;
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
- Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Anastasia S. Sukhova
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
| | - Nikolay A. Tkachenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia;
| | - Yuriy P. Skryabin
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
| | - Anastasia V. Popova
- State Research Center for Applied Microbiology and Biotechnology, City District Serpukhov, Moscow Region, 142279 Obolensk, Russia; (A.S.S.); (Y.P.S.)
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Peters DL, Gaudreault F, Chen W. Functional domains of Acinetobacter bacteriophage tail fibers. Front Microbiol 2024; 15:1230997. [PMID: 38690360 PMCID: PMC11058221 DOI: 10.3389/fmicb.2024.1230997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 03/08/2024] [Indexed: 05/02/2024] Open
Abstract
A rapid increase in antimicrobial resistant bacterial infections around the world is causing a global health crisis. The Gram-negative bacterium Acinetobacter baumannii is categorized as a Priority 1 pathogen for research and development of new antimicrobials by the World Health Organization due to its numerous intrinsic antibiotic resistance mechanisms and ability to quickly acquire new resistance determinants. Specialized phage enzymes, called depolymerases, degrade the bacterial capsule polysaccharide layer and show therapeutic potential by sensitizing the bacterium to phages, select antibiotics, and serum killing. The functional domains responsible for the capsule degradation activity are often found in the tail fibers of select A. baumannii phages. To further explore the functional domains associated with depolymerase activity, tail-associated proteins of 71 sequenced and fully characterized phages were identified from published literature and analyzed for functional domains using InterProScan. Multisequence alignments and phylogenetic analyses were conducted on the domain groups and assessed in the context of noted halo formation or depolymerase characterization. Proteins derived from phages noted to have halo formation or a functional depolymerase, but no functional domain hits, were modeled with AlphaFold2 Multimer, and compared to other protein models using the DALI server. The domains associated with depolymerase function were pectin lyase-like (SSF51126), tailspike binding (cd20481), (Trans)glycosidases (SSF51445), and potentially SGNH hydrolases. These findings expand our knowledge on phage depolymerases, enabling researchers to better exploit these enzymes for therapeutic use in combating the antimicrobial resistance crisis.
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Affiliation(s)
- Danielle L. Peters
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON, Canada
| | | | - Wangxue Chen
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON, Canada
- Department of Biology, Brock University, St. Catharines, ON, Canada
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Raees F, Harun A, Ahmed A, Deris ZZ. Potential Usefulness of Bacteriophages for the Treatment of Multidrug-Resistant Acinetobacter Infection. Malays J Med Sci 2023; 30:7-22. [PMID: 37928784 PMCID: PMC10624448 DOI: 10.21315/mjms2023.30.5.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/11/2022] [Indexed: 11/07/2023] Open
Abstract
Bacteriophages were discovered in early 20th century. However, the interest in bacteriophage research was reduced with the discovery of antibiotics. With the increasing number of infections due to multidrug-resistant (MDR) organisms, the potential usefulness of bacteriophages as therapeutic agents has been re-evaluated. In this review, we found that more than 30 lytic bacteriophages that infect Acinetobacter species have been characterised. These are mainly members of Caudovirales, with genome sizes ranging from 31 kb to 234 kb and G+C contents ranging from 33.5% to 45.5%. The host range can be as low as < 10% of all tested Acinetobacter strains. Fourteen published murine trials indicated positive outcomes in bacteriophage-treated groups. Only two case reports were pertaining to the use of bacteriophages in the treatment of Acinetobacter infections in humans; in both cases, the infections were resolved with bacteriophage therapy. The use of bacteriophages has been associated with reduced Acinetobacter burden in the environment, as shown in two studies. The major limitation of bacteriophage therapy is its highly selective host strain. In conclusion, the potential usefulness of bacteriophage therapy for the treatment of MDR Acinetobacter species has been documented only in limited studies and more research is needed prior to its extensive use in clinical practice.
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Affiliation(s)
- Fahad Raees
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Department of Microbiology, College of Medicine, Umm al-Qura University, Makkah, Kingdom of Saudi Arabia
| | - Azian Harun
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Hospital Universiti Sains Malaysia, Kelantan, Malaysia
| | - Abdalla Ahmed
- Department of Microbiology, College of Medicine, Umm al-Qura University, Makkah, Kingdom of Saudi Arabia
| | - Zakuan Zainy Deris
- Department of Medical Microbiology and Parasitology, School of Medical Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Hospital Universiti Sains Malaysia, Kelantan, Malaysia
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Peters DL, Davis CM, Harris G, Zhou H, Rather PN, Hrapovic S, Lam E, Dennis JJ, Chen W. Characterization of Virulent T4-Like Acinetobacter baumannii Bacteriophages DLP1 and DLP2. Viruses 2023; 15:v15030739. [PMID: 36992448 PMCID: PMC10051250 DOI: 10.3390/v15030739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/16/2023] Open
Abstract
The world is currently facing a global health crisis due to the rapid increase in antimicrobial-resistant bacterial infections. One of the most concerning pathogens is Acinetobacter baumannii, which is listed as a Priority 1 pathogen by the World Health Organization. This Gram-negative bacterium has many intrinsic antibiotic resistance mechanisms and the ability to quickly acquire new resistance determinants from its environment. A limited number of effective antibiotics against this pathogen complicates the treatment of A. baumannii infections. A potential treatment option that is rapidly gaining interest is “phage therapy”, or the clinical application of bacteriophages to selectively kill bacteria. The myoviruses DLP1 and DLP2 (vB_AbaM-DLP_1 and vB_AbaM-DLP_2, respectively) were isolated from sewage samples using a capsule minus variant of A. baumannii strain AB5075. Host range analysis of these phages against 107 A. baumannii strains shows a limited host range, infecting 15 and 21 for phages DLP1 and DLP2, respectively. Phage DLP1 has a large burst size of 239 PFU/cell, a latency period of 20 min, and virulence index of 0.93. In contrast, DLP2 has a smaller burst size of 24 PFU/cell, a latency period of 20 min, and virulence index of 0.86. Both phages show potential for use as therapeutics to combat A. baumannii infections.
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Affiliation(s)
- Danielle L. Peters
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Correspondence:
| | - Carly M. Davis
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Greg Harris
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Hongyan Zhou
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
| | - Philip N. Rather
- Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322, USA
- Research Service, Atlanta VA Medical Center, Decatur, GA 30033, USA
| | - Sabahudin Hrapovic
- Aquatic and Crop Resource Development (ACRD) Research Center, National Research Council Canada, Montreal, QC H4P 2R2, Canada
| | - Edmond Lam
- Aquatic and Crop Resource Development (ACRD) Research Center, National Research Council Canada, Montreal, QC H4P 2R2, Canada
| | - Jonathan J. Dennis
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Wangxue Chen
- Human Health Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Department of Biology, Brock University, St. Catharines, ON L2S 3A1, Canada
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Patpatia S, Schaedig E, Dirks A, Paasonen L, Skurnik M, Kiljunen S. Rapid hydrogel-based phage susceptibility test for pathogenic bacteria. Front Cell Infect Microbiol 2022; 12:1032052. [PMID: 36569196 PMCID: PMC9771388 DOI: 10.3389/fcimb.2022.1032052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Phage therapy is one alternative to cure infections caused by antibiotic resistant bacteria. Due to the narrow host range of phages, hundreds to thousands of phages are required to cover the diversity of bacterial pathogens. In personalized phage therapy, fast selection of the phages for individual patients is essential for successful therapy. The aims of this study were to set up a rapid hydrogel-based liquid phage susceptibility assay (PST) for the selection of phages for therapeutic use and to establish a "ready-to-screen" plate concept, where phages are readily stored in hydrogel as small droplets in microtiter plate wells. We first tested four commercially available hydrogels (GrowDex, Askina, Purilon, and Intrasite) for their suitability as phage matrices in PSTs with four phages, two of which infecting Escherichia coli and two Staphylococcus aureus. Of these four hydrogels, GrowDex was the best matrix for PST, as it did not inhibit bacterial growth, released phages quickly when mixed with bacterial culture, and maintained phage viability well. We then optimized the assay for both optical density and microscopy readers using GrowDex as matrix with 23 bacterial strains representing 10 different species and 23 phages possessing different morphologies and genome sizes. When the bacterial growth was monitored by microscopy reader, the PST was executed in just 3 hours, and there was no need for overnight culturing bacterial cells prior to the assay, whereas using optical density reader, bacteria had to be pre-cultured overnight, and the assay time was five hours. Finally, we evaluated the effect of three different chemical stabilizers (trehalose, hyaluronic acid, and gelatin) in a six-month stability assay with six model phages. These phages assay behaved very differently in respect to the chemical stabilizers, and there was not a single stabilizer suitable for all phages. However, when gelatin (0.01%) or hyaluronic acid (0.2 mg/ml) was used as stabilizer, all tested phages were still considered as positives in PST after a six-month storage in 1 ml volume. In "ready-to-screen" plates, the differences in phage stabilities were even more profound, varying from two to six months for the most and least stable phages, respectively.
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Affiliation(s)
- Sheetal Patpatia
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Eric Schaedig
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Anna Dirks
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | | | - Mikael Skurnik
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Saija Kiljunen
- Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland,*Correspondence: Saija Kiljunen,
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Cheng M, Luo M, Xi H, Zhao Y, Le S, Chen LK, Tan D, Guan Y, Wang T, Han W, Wu N, Zhu T, Gu J. The characteristics and genome analysis of vB_ApiP_XC38, a novel phage infecting Acinetobacter pittii. Virus Genes 2020; 56:498-507. [PMID: 32449140 DOI: 10.1007/s11262-020-01766-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 05/11/2020] [Indexed: 12/27/2022]
Abstract
Acinetobacter pittii is an important pathogen causing nosocomial infection worldwide. In this study, a multidrug-resistant A. pittii ABC38 was used as host bacterium to isolate the lytic phage vB_ApiP_XC38. The biological characteristics of vB_ApiP_XC38 were studied and the genome was sequenced and analyzed. vB_ApiP_XC38 belonged to Podoviridae family. The phage had double-stranded genome, which comprised 79,328 bp with 39.58% G+C content displaying very low similarity (< 1% identity) with published genomes of other phages and bacteria. A total of 97 open reading frames (ORFs) were predicted and contained nucleotide metabolism and replication module, structural components module, and lysis module. The ANI, AAI, and phylogenetic analysis indicated that all phages were found distant from vB_ApiP_XC38. Altogether, morphological, genomics, and phylogenetic analysis suggest that vB_ApiP_XC38 is more likely a novel phage of A. pittii.
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Affiliation(s)
- Mengjun Cheng
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Man Luo
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Hengyu Xi
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Yunze Zhao
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Shuai Le
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China.,Department of Microbiology, Army Medical University, Chongqing, 400038, China
| | - Li-Kuang Chen
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Demeng Tan
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China
| | - Yuan Guan
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China
| | - Tianqi Wang
- College of Clinical Medicine, Jilin University, Changchun, 130021, China
| | - Wenyu Han
- Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.,Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou, 225009, China
| | - Nannan Wu
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China.
| | - Tongyu Zhu
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China.
| | - Jingmin Gu
- Shanghai Institute of Phage, Shanghai Public Health Clinical Center, Fudan University, Shanghai, 201508, China. .,Key Laboratory of Zoonosis Research, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, 130062, China.
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Styles KM, Thummeepak R, Leungtongkam U, Smith SE, Christie GS, Millard A, Moat J, Dowson CG, Wellington EMH, Sitthisak S, Sagona AP. Investigating Bacteriophages Targeting the Opportunistic Pathogen Acinetobacter baumannii. Antibiotics (Basel) 2020; 9:antibiotics9040200. [PMID: 32331271 PMCID: PMC7235909 DOI: 10.3390/antibiotics9040200] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/18/2020] [Accepted: 04/20/2020] [Indexed: 11/19/2022] Open
Abstract
The multi-drug resistance of the opportunistic pathogen Acinetobacter baumannii is of growing concern, with many clinical isolates proving to be resistant to last resort as well as front line antibiotic treatments. The use of bacteriophages is an attractive alternative to controlling and treating this emerging nosocomial pathogen. In this study, we have investigated bacteriophages collected from hospital wastewater in Thailand and we have explored their activity against clinical isolates of A. baumannii. Bacteriophage vB_AbaM_PhT2 showed 28% host range against 150 multidrug resistant (MDR) isolates and whole genome sequencing did not detect any known virulence factors or antibiotic resistance genes. Purified vB_AbaM_PhT2 samples had endotoxin levels below those recommended for preclinical trials and were not shown to be directly cytotoxic to human cell lines in vitro. The treatment of human brain and bladder cell lines grown in the presence of A. baumannii with this bacteriophage released significantly less lactate dehydrogenase compared to samples with no bacteriophage treatment, indicating that vB_AbaM_PhT2 can protect from A. baumannii induced cellular damage. Our results have also indicated that there is synergy between this bacteriophage and the end line antibiotic colistin. We therefore propose bacteriophage vB_AbaM_PhT2 as a good candidate for future research and for its potential development into a surface antimicrobial for use in hospitals.
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Affiliation(s)
- Kathryn M. Styles
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
| | - Rapee Thummeepak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Muang, Phitsanulok 65000, Thailand; (R.T.); (U.L.); (S.S.)
| | - Udomluk Leungtongkam
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Muang, Phitsanulok 65000, Thailand; (R.T.); (U.L.); (S.S.)
| | - Sophie E. Smith
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
| | | | - Andrew Millard
- Department of Genetics and Genome Biology, Leicester University, Leicester LE1 7RH, UK;
| | - John Moat
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
- Warwick Antimicrobial Screening Facility, University of Warwick, Coventry CV4 7AL, UK
| | - Christopher G. Dowson
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
- Warwick Antimicrobial Screening Facility, University of Warwick, Coventry CV4 7AL, UK
| | - Elizabeth M. H. Wellington
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
| | - Sutthirat Sitthisak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Muang, Phitsanulok 65000, Thailand; (R.T.); (U.L.); (S.S.)
| | - Antonia P. Sagona
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (K.M.S.); (S.E.S.); (J.M.); (C.G.D.); (E.M.H.W.)
- Correspondence:
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Hietala V, Horsma-Heikkinen J, Carron A, Skurnik M, Kiljunen S. The Removal of Endo- and Enterotoxins From Bacteriophage Preparations. Front Microbiol 2019; 10:1674. [PMID: 31396188 PMCID: PMC6664067 DOI: 10.3389/fmicb.2019.01674] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/08/2019] [Indexed: 12/11/2022] Open
Abstract
The production of phages for therapeutic purposes demands fast, efficient and scalable purification procedures. Phage lysates have a wide range of impurities, of which endotoxins of gram-negative bacteria and protein toxins produced by many pathogenic bacterial species are harmful to humans. The highest allowed endotoxin concentration for parenterally applied medicines is 5 EU/kg/h. The aim of this study was to evaluate the feasibility of different purification methods in endotoxin and protein toxin removal in the production of phage preparations for clinical use. In the purification assays, we utilized three phages: Escherichia phage vB_EcoM_fHoEco02, Acinetobacter phage vB_ApiM_fHyAci03, and Staphylococcus phage vB_SauM_fRuSau02. The purification methods tested in the study were precipitation with polyethylene glycol, ultracentrifugation, ultrafiltration, anion exchange chromatography, octanol extraction, two different endotoxin removal columns, and different combinations thereof. The efficiency of the applied purification protocols was evaluated by measuring phage titer and either endotoxins or staphylococcal enterotoxins A and C (SEA and SEC, respectively) from samples taken from different purification steps. The most efficient procedure in endotoxin removal was the combination of ultrafiltration and EndoTrap HD affinity column, which was able to reduce the endotoxin-to-phage ratio of vB_EcoM_fHoEco02 lysate from 3.5 × 104 Endotoxin Units (EU)/109 plaque forming units (PFU) to 0.09 EU/109 PFU. The combination of ultrafiltration and anion exchange chromatography resulted in ratio 96 EU/109 PFU, and the addition of octanol extraction step into this procedure still reduced this ratio threefold. The other methods tested either resulted to less efficient endotoxin removal or required the use of harmful chemicals that should be avoided when producing phage preparations for medical use. Ultrafiltration with 100,000 MWCO efficiently removed enterotoxins from vB_SauM_fRuSau02 lysate (from 1.3 to 0.06 ng SEA/109 PFU), and anion exchange chromatography reduced the enterotoxin concentration below 0.25 ng/ml, the detection limit of the assay.
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Affiliation(s)
- Ville Hietala
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jenni Horsma-Heikkinen
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Annelie Carron
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Mikael Skurnik
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Division of Clinical Microbiology, HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Saija Kiljunen
- Department of Bacteriology and Immunology, Human Microbiome Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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