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Bai J, Raustad N, Denoncourt J, van Opijnen T, Geisinger E. Genome-wide phage susceptibility analysis in Acinetobacter baumannii reveals capsule modulation strategies that determine phage infectivity. PLoS Pathog 2023; 19:e1010928. [PMID: 37289824 PMCID: PMC10249906 DOI: 10.1371/journal.ppat.1010928] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 04/27/2023] [Indexed: 06/10/2023] Open
Abstract
Phage have gained renewed interest as an adjunctive treatment for life-threatening infections with the resistant nosocomial pathogen Acinetobacter baumannii. Our understanding of how A. baumannii defends against phage remains limited, although this information could lead to improved antimicrobial therapies. To address this problem, we identified genome-wide determinants of phage susceptibility in A. baumannii using Tn-seq. These studies focused on the lytic phage Loki, which targets Acinetobacter by unknown mechanisms. We identified 41 candidate loci that increase susceptibility to Loki when disrupted, and 10 that decrease susceptibility. Combined with spontaneous resistance mapping, our results support the model that Loki uses the K3 capsule as an essential receptor, and that capsule modulation provides A. baumannii with strategies to control vulnerability to phage. A key center of this control is transcriptional regulation of capsule synthesis and phage virulence by the global regulator BfmRS. Mutations hyperactivating BfmRS simultaneously increase capsule levels, Loki adsorption, Loki replication, and host killing, while BfmRS-inactivating mutations have the opposite effect, reducing capsule and blocking Loki infection. We identified novel BfmRS-activating mutations, including knockouts of a T2 RNase protein and the disulfide formation enzyme DsbA, that hypersensitize bacteria to phage challenge. We further found that mutation of a glycosyltransferase known to alter capsule structure and bacterial virulence can also cause complete phage resistance. Finally, additional factors including lipooligosaccharide and Lon protease act independently of capsule modulation to interfere with Loki infection. This work demonstrates that regulatory and structural modulation of capsule, known to alter A. baumannii virulence, is also a major determinant of susceptibility to phage.
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Affiliation(s)
- Jinna Bai
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Nicole Raustad
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Jason Denoncourt
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Tim van Opijnen
- Broad Institute of MIT and Harvard, CISID, Cambridge, Massachusetts, United States of America
| | - Edward Geisinger
- Department of Biology, Northeastern University, Boston, Massachusetts, United States of America
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Timoshina OY, Kasimova AA, Shneider MM, Matyuta IO, Nikolaeva AY, Evseev PV, Arbatsky NP, Shashkov AS, Chizhov AO, Shelenkov AA, Mikhaylova YV, Slukin PV, Volozhantsev NV, Boyko KM, Knirel YA, Miroshnikov KA, Popova AV. Friunavirus Phage-Encoded Depolymerases Specific to Different Capsular Types of Acinetobacter baumannii. Int J Mol Sci 2023; 24:ijms24109100. [PMID: 37240444 DOI: 10.3390/ijms24109100] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/06/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Acinetobacter baumannii is a critical priority nosocomial pathogen that produces a variety of capsular polysaccharides (CPSs), the primary receptors for specific depolymerase-carrying phages. In this study, the tailspike depolymerases (TSDs) encoded in genomes of six novel Friunaviruses, APK09, APK14, APK16, APK86, APK127v, APK128, and one previously described Friunavirus phage, APK37.1, were characterized. For all TSDs, the mechanism of specific cleavage of corresponding A. baumannii capsular polysaccharides (CPSs) was established. The structures of oligosaccharide fragments derived from K9, K14, K16, K37/K3-v1, K86, K127, and K128 CPSs degradation by the recombinant depolymerases have been determined. The crystal structures of three of the studied TSDs were obtained. A significant reduction in mortality of Galleria mellonella larvae infected with A. baumannii of K9 capsular type was shown in the example of recombinant TSD APK09_gp48. The data obtained will provide a better understanding of the interaction of phage-bacterial host systems and will contribute to the formation of principles of rational usage of lytic phages and phage-derived enzymes as antibacterial agents.
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Affiliation(s)
- Olga Y Timoshina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
| | - Anastasia A Kasimova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Mikhail M Shneider
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Ilya O Matyuta
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
- Center for Photonics and 2D Materials, Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Alena Y Nikolaeva
- Complex of NBICS Technologies, National Research Center "Kurchatov Institute", 123182 Moscow, Russia
| | - Peter V Evseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Nikolay P Arbatsky
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexander S Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Alexander O Chizhov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Andrey A Shelenkov
- Central Scientific Research Institute of Epidemiology, 111123 Moscow, Russia
| | - Yulia V Mikhaylova
- Central Scientific Research Institute of Epidemiology, 111123 Moscow, Russia
| | - Pavel V Slukin
- State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
| | - Nikolay V Volozhantsev
- State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
| | - Konstantin M Boyko
- Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Konstantin A Miroshnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Anastasia V Popova
- State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
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Timoshina OY, Kasimova AA, Shneider MM, Arbatsky NP, Shashkov AS, Shelenkov AA, Mikhailova YV, Popova AV, Hall RM, Knirel YA, Kenyon JJ. Loss of a Branch Sugar in the Acinetobacter baumannii K3-Type Capsular Polysaccharide Due To Frameshifts in the gtr6 Glycosyltransferase Gene Leads To Susceptibility To Phage APK37.1. Microbiol Spectr 2023; 11:e0363122. [PMID: 36651782 PMCID: PMC9927144 DOI: 10.1128/spectrum.03631-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 12/21/2022] [Indexed: 01/19/2023] Open
Abstract
The type of capsular polysaccharide (CPS) on the cell surface of Acinetobacter baumannii can determine the specificity of lytic bacteriophage under consideration for therapeutic use. Here, we report the isolation of a phage on an extensively antibiotic resistant ST2 A. baumannii isolate AB5001 that carries the KL3 CPS biosynthesis gene cluster predicting a K3-type CPS. As the phage did not infect isolates carrying KL3 or KL22 and known to produce K3 CPS, the structure of the CPS isolated from A. baumannii AB5001 was determined. AB5001 produced a variant CPS form, K3-v1, that lacks the β-d-GlсpNAc side chain attached to the d-Galp residue in the K3 structure. Inspection of the KL3 sequence in the genomes of AB5001 and other phage-susceptible isolates with a KL3 locus revealed single-base deletions in gtr6, causing loss of the Gtr6 glycosyltransferase that adds the missing d-GlсpNAc side chain to the K3 CPS. Hence, the presence of this sugar profoundly restricts the ability of the phage to digest the CPS. The 41-kb linear double-stranded DNA (dsDNA) phage genome was identical to the genome of a phage isolated on a K37-producing isolate and thus was named APK37.1. APK37.1 also infected isolates carrying KL116. Consistent with this, K3-v1 resembles the K37 and K116 structures. APK37.1 is a Friunavirus belonging to the Autographiviridae family. The phage-encoded tail spike depolymerase DpoAPK37.1 was not closely related to Dpo encoded by other sequenced Friunaviruses, including APK37 and APK116. IMPORTANCE Lytic bacteriophage have potential for the treatment of otherwise untreatable extensively antibiotic-resistant bacteria. For Acinetobacter baumannii, most phage exhibit specificity for the type of capsular polysaccharide (CPS) produced on the cell surface. However, resistance can arise via mutations in CPS genes that abolish this phage receptor. Here, we show that single-base deletions in a CPS gene result in alteration of the final structure rather than deletion of the capsule layer and hence affect the ability of a newly reported podophage to infect strains producing the K3 CPS.
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Affiliation(s)
- Olga Y. Timoshina
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Anastasiya A. Kasimova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Mikhail M. Shneider
- M. M. Shemyakin and Yu. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay P. Arbatsky
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexander S. Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | | | | | - Anastasiya V. Popova
- State Research Center for Applied Microbiology and Biotechnology, Obolensk, Russia
| | - Ruth M. Hall
- School of Life and Environmental Science, University of Sydney, Sydney, Australia
| | - Yuriy A. Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Johanna J. Kenyon
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
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Valcek A, Collier J, Botzki A, Van der Henst C. Acinetobase: the comprehensive database and repository of Acinetobacter strains. Database (Oxford) 2022; 2022:6837280. [PMID: 36412325 PMCID: PMC10103187 DOI: 10.1093/database/baac099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/20/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022]
Abstract
Acinetobacter baumannii is one of the most problematic nosocomial pathogens that can efficiently thrive within hospital settings, mainly due to resistances toward antibiotics, desiccation, disinfectants, human serum and oxidative stress. Recently, increased resistance against last-resort antibiotics earns this bacterium the highest priority concern classified by the Centers for Disease Control and Prevention and the World Health Organization. An obvious hallmark of this bacterium is the high heterogeneity observed among A. baumannii isolates, with a limited core genome. This feature complexifies the study of A. baumannii bacteria as an entity, subsequently reflected in a diversity of phenotypes of not only antimicrobial and environmental resistance but also virulence. A high degree of genome plasticity, along with the use of a limited subset of established strains, can lead to strain-specific observations, decreasing the global understanding of this pathogenic agent. Phenotypic variability of A. baumannii strains is easily observable such as with the macrocolony morphologies, in vitro and in vivo virulence, natural competence level, production of different capsular polysaccharide structures and cellular densities. Some strains encode an extensive amount of virulence factors, while others, including the established strains, lack several key ones. The lack/excess of genes or specific physiological processes might interfere with in vivo and in vitro experiments, thus providing a limited impact on the global understanding of Acinetobacter bacteria. As an answer to the high heterogeneity among A. baumannii strains, we propose a first comprehensive database that includes the bacterial strains and the associated phenotypic and genetic data. This new repository, freely accessible to the entire scientific community, allows selecting the best bacterial isolate(s) related to any biological question, using an efficient and fast exchange platform. Database URL: https://acinetobase.vib.be/.
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Affiliation(s)
- Adam Valcek
- Vrije Universiteit Brussel (VUB), Center for Structural Biology, Pleinlaan 2, Building E-3, Brussels 1050, Belgium
| | - James Collier
- VIB Bioinformatics Core, Rijvischestraat 126 3R, Zwijnaarde-Ghent 9052, Belgium
| | - Alexander Botzki
- VIB Bioinformatics Core, Rijvischestraat 126 3R, Zwijnaarde-Ghent 9052, Belgium
| | - Charles Van der Henst
- Vrije Universiteit Brussel (VUB), Center for Structural Biology, Pleinlaan 2, Building E-3, Brussels 1050, Belgium
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Cahill SM, Hall RM, Kenyon JJ. An update to the database for Acinetobacter baumannii capsular polysaccharide locus typing extends the extensive and diverse repertoire of genes found at and outside the K locus. Microb Genom 2022; 8. [PMID: 36214673 DOI: 10.1099/mgen.0.000878] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several novel non-antibiotic therapeutics for the critical priority bacterial pathogen, Acinetobacter baumannii, rely on specificity to the cell-surface capsular polysaccharide (CPS). Hence, prediction of CPS type deduced from genes in whole genome sequence data underpins the development and application of these therapies. In this study, we provide a comprehensive update to the A. baumannii K locus reference sequence database for CPS typing (available in Kaptive v. 2.0.1) to include 145 new KL, providing a total of 237 KL reference sequences. The database was also reconfigured for compatibility with the updated Kaptive v. 2.0.0 code that enables prediction of 'K type' from special logic parameters defined by detected combinations of KL and additional genes outside the K locus. Validation of the database against 8994 publicly available A. baumannii genome assemblies from NCBI databases identified the specific KL in 73.45 % of genomes with perfect, very high or high confidence. Poor sequence quality or the presence of insertion sequences were the main reasons for lower confidence levels. Overall, 17 KL were overrepresented in available genomes, with KL2 the most common followed by the related KL3 and KL22. Substantial variation in gene content of the central portion of the K locus, that usually includes genes specific to the CPS type, included 34 distinct groups of genes for synthesis of various complex sugars and >400 genes for forming linkages between sugars or adding non-sugar substituents. A repertoire of 681 gene types were found across the 237 KL, with 88.4 % found in <5 % of KL.
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Affiliation(s)
- Sarah M Cahill
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Ruth M Hall
- School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Johanna J Kenyon
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
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Involvement of a Phage-Encoded Wzy Protein in the Polymerization of K127 Units To Form the Capsular Polysaccharide of Acinetobacter baumannii Isolate 36-1454. Microbiol Spectr 2022; 10:e0150321. [PMID: 35475638 PMCID: PMC9241936 DOI: 10.1128/spectrum.01503-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A comprehensive understanding of capsular polysaccharide (CPS) diversity is critical to implementation of phage therapy to treat panresistant Acinetobacter baumannii infections. Predictions from genome sequences can assist identification of the CPS type but can be complicated if genes outside the K locus (CPS biosynthesis gene cluster) are involved. Here, the CPS produced by A. baumannii clinical isolate 36-1454 carrying a novel K locus, KL127, was determined and compared to other CPSs. KL127 differs from KL128 in only two of the glycosyltransferase (gtr) genes. The K127 unit in 36-1454 CPS was the pentasaccharide β-d-Glcp-(1→6)-d-β-GalpNAc-(1→6)-α-d-Galp-(1→6)-β-d-Glсp-(1→3)-β-d-GalpNAc in which d-Glcp at position 4 replaces d-Galp in K128, and the glycosyltransferases encoded by the different gtr genes form the surrounding linkages. However, although the KL127 and KL128 gene clusters encode nearly identical Wzy polymerases, the linkages between K units that form the CPS chains are different, i.e., β-d-GalpNAc-(1→3)-d-Galp in 36-1454 (K127) and β-d-GalpNAc-(1→4)-d-Galp in KZ-1093 (K128). The linkage between K127 units in 36-1454 is the same as the K-unit linkage in five known CPS structures, and a gene encoding a Wzy protein related to the Wzy of the corresponding K loci was found encoded in a prophage genome in the 36-1454 chromosome. Closely related Wzy proteins were encoded in unrelated phage in available KL127-carrying genomes. However, a clinical isolate, KZ-1257, carrying KL127 but not the prophage was found, and K127 units in the KZ-1257 CPS were β-d-GalpNAc-(1→4)-d-Galp linked, confirming that WzyKL127 forms this linkage and thus that the phage-encoded WzyPh1 forms the β-d-GalpNAc-(1→3)-d-Galp linkage in 36-1454. IMPORTANCE Bacteriophage therapy is an attractive innovative treatment for infections caused by extensively drug resistant Acinetobacter baumannii, for which there are few effective antibiotic treatments remaining. Capsular polysaccharide (CPS) is a primary receptor for many lytic bacteriophages, and thus knowledge of the chemical structures of CPS produced by the species will underpin the identification of suitable phages for therapeutic cocktails. However, recent research has shown that some isolates carry additional genes outside of the CPS biosynthesis K locus, which can modify the CPS structure. These changes can subsequently alter phage receptor sites and may be a method utilized for natural phage resistance. Hence, it is critical to understand the genetics that drive CPS synthesis and the extent to which genes outside of the K locus can affect the CPS structure.
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