eprintid: 10204379 rev_number: 6 eprint_status: archive userid: 699 dir: disk0/10/20/43/79 datestamp: 2025-02-06 17:06:15 lastmod: 2025-02-06 17:06:15 status_changed: 2025-02-06 17:06:15 type: article metadata_visibility: show sword_depositor: 699 creators_name: Phitchayapak, Wintachai creators_name: Santini, Joanne creators_name: Renuka, Thonguppatham creators_name: Maria, Stroyakovski creators_name: Komwit, Surachat creators_name: Apirchart, Atipairin title: Isolation, Characterization, and Anti-Biofilm Activity of a Novel Kaypoctavirus Against K24 Capsular Type, Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates ispublished: pub divisions: UCL divisions: B02 divisions: C08 divisions: D09 divisions: G03 keywords: Antibacterial activity; bacteriophage; biofilms; K24 capsular type; Klebsiella pneumoniae; phage therapy note: This work is licensed under a Creative Commons License. The images or other third-party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ abstract: The significant outbreak of multidrug-resistant Klebsiella pneumoniae has emerged as a primary global concern associated with high morbidity and mortality rates. Certain strains of K. pneumoniae are highly resistant to most antibiotics available in clinical practice, exacerbating the challenge of bacterial infections. Methods: Phage vB_KpnP_PW7 (vKPPW7) was isolated and characterized. Its morphology, stability, adsorption rate, one-step growth curve, lytic activity, whole-genome sequence analysis, and antibacterial and antibiofilm activities were evaluated. Results: The virulent phage has a 73,658 bp linear dsDNA genome and was classified as a new species of the genus Kaypoctavirus, subfamily Enquatrovirinae, and family Schitoviridae. Phage vKPPW7 has a high adsorption rate, a short latent period, and a large burst size. The phage showed activity against 18 K. pneumoniae isolates with the K24 capsular type but was unable to lyse K. pneumoniae isolates whose capsular type was not classified as K24. Additionally, phage vKPPW7 demonstrated strong stability across various temperatures and pH values. The phage exhibited antibacterial activity, and scanning electron microscopy (SEM) confirmed its ability to lyse MDR K. pneumoniae with the K24 capsular type. Furthermore, phage vKPPW7 effectively removed preformed biofilm and prevented biofilm formation, resulting in reduced biofilm biomass and biofilm viability compared to controls. The architecture of phage-treated biofilms was confirmed under SEM. Conclusions: These findings suggest that phage vKPPW7 holds promise for development as a therapeutic or biocontrol agent. date: 2025-02-05 date_type: published publisher: MDPI AG official_url: https://www.mdpi.com/2079-6382/14/2/157 oa_status: green full_text_type: pub language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2358241 doi: 10.3390/antibiotics14020157 lyricists_name: Santini, Giovanna lyricists_id: JMSAN31 actors_name: Santini, Giovanna actors_id: JMSAN31 actors_role: owner full_text_status: public publication: Antibiotics volume: 14 number: 2 article_number: 157 citation: Phitchayapak, Wintachai; Santini, Joanne; Renuka, Thonguppatham; Maria, Stroyakovski; Komwit, Surachat; Apirchart, Atipairin; (2025) Isolation, Characterization, and Anti-Biofilm Activity of a Novel Kaypoctavirus Against K24 Capsular Type, Multidrug-Resistant Klebsiella pneumoniae Clinical Isolates. Antibiotics , 14 (2) , Article 157. 10.3390/antibiotics14020157 <https://doi.org/10.3390/antibiotics14020157>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10204379/1/antibiotics-14-00157.pdf