{"title":"Isolation and characterization of bacteriophages against antibiotic-resistance <i>Pseudomonas aeruginosa</i>.","authors":"Parisa Abedi Elkhichi, Sara Bahonar, Hanieh Shirazi, Aghil Bahramian, Maryam Kazemi Aghdam, Mona Ghazi","doi":"10.18502/ijm.v18i4.22193","DOIUrl":null,"url":null,"abstract":"<p><strong>Background and objectives: </strong>As an important opportunistic pathogen, <i>Pseudomonas aeruginosa</i> is associated with severe infections and increasing antimicrobial resistance. The growing prevalence of multidrug-resistant (MDR) strains has renewed interest in bacteriophages as alternative antibacterial agents. The present study sought to isolate and characterize lytic bacteriophages from hospital wastewater active against antibiotic-resistant clinical <i>P. aeruginosa</i> isolates.</p><p><strong>Materials and methods: </strong>Fifty clinical isolates of <i>P. aeruginosa</i> were obtained and tested for antimicrobial susceptibility. Bacteriophages were isolated from hospital wastewater by enrichment and spot assay screening, followed by plaque purification and titration using the double-layer agar method. The host range of purified phages was evaluated against the clinical isolates. Adsorption assays and one-step growth experiments were performed to determine adsorption efficiency, latent period, and burst size. Transmission electron microscopy (TEM) was used to examine phage morphology.</p><p><strong>Results: </strong>A considerable proportion of the clinical isolates showed multidrug-resistant phenotypes, and a considerable number were also classified as extensively drug-resistant. Four lytic bacteriophages, designated HSP1-HSP4, were successfully isolated and purified. All produced clear plaques and reached high titers. Host range analysis showed variable lytic spectra, with HSP1 exhibiting the broadest activity and showing lytic activity against 70% of the tested isolates, followed by HSP2 (58%), HSP3 (48%), and HSP4 (40%). Adsorption analysis indicated that over 80% of phage particles attached to their host cells within 10 minutes, while HSP1 exhibited the highest adsorption efficiency at 93.6%. A short latent period of approximately 20 minutes was observed for all four phages, and burst sizes ranged from 56 to 65 PFU/cell. Transmission electron microscopy revealed isometric heads and contractile tails, morphologically consistent with tailed phages of the class <i>Caudoviricetes</i>.</p><p><strong>Conclusion: </strong>Hospital wastewater can serve as a practical source for the isolation of lytic bacteriophages active against antibiotic-resistant <i>P. aeruginosa.</i> The in vitro properties of the isolated phages support their further evaluation as candidate antibacterial agents against resistant <i>P. aeruginosa</i>. However, genomic characterization, phage-antibiotic interaction analyses, and in vivo investigations are required before their broader applicability can be determined.</p>","PeriodicalId":14633,"journal":{"name":"Iranian Journal of Microbiology","volume":"18 4","pages":"499-508"},"PeriodicalIF":1.9000,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13490637/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Iranian Journal of Microbiology","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.18502/ijm.v18i4.22193","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MICROBIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Background and objectives: As an important opportunistic pathogen, Pseudomonas aeruginosa is associated with severe infections and increasing antimicrobial resistance. The growing prevalence of multidrug-resistant (MDR) strains has renewed interest in bacteriophages as alternative antibacterial agents. The present study sought to isolate and characterize lytic bacteriophages from hospital wastewater active against antibiotic-resistant clinical P. aeruginosa isolates.
Materials and methods: Fifty clinical isolates of P. aeruginosa were obtained and tested for antimicrobial susceptibility. Bacteriophages were isolated from hospital wastewater by enrichment and spot assay screening, followed by plaque purification and titration using the double-layer agar method. The host range of purified phages was evaluated against the clinical isolates. Adsorption assays and one-step growth experiments were performed to determine adsorption efficiency, latent period, and burst size. Transmission electron microscopy (TEM) was used to examine phage morphology.
Results: A considerable proportion of the clinical isolates showed multidrug-resistant phenotypes, and a considerable number were also classified as extensively drug-resistant. Four lytic bacteriophages, designated HSP1-HSP4, were successfully isolated and purified. All produced clear plaques and reached high titers. Host range analysis showed variable lytic spectra, with HSP1 exhibiting the broadest activity and showing lytic activity against 70% of the tested isolates, followed by HSP2 (58%), HSP3 (48%), and HSP4 (40%). Adsorption analysis indicated that over 80% of phage particles attached to their host cells within 10 minutes, while HSP1 exhibited the highest adsorption efficiency at 93.6%. A short latent period of approximately 20 minutes was observed for all four phages, and burst sizes ranged from 56 to 65 PFU/cell. Transmission electron microscopy revealed isometric heads and contractile tails, morphologically consistent with tailed phages of the class Caudoviricetes.
Conclusion: Hospital wastewater can serve as a practical source for the isolation of lytic bacteriophages active against antibiotic-resistant P. aeruginosa. The in vitro properties of the isolated phages support their further evaluation as candidate antibacterial agents against resistant P. aeruginosa. However, genomic characterization, phage-antibiotic interaction analyses, and in vivo investigations are required before their broader applicability can be determined.
期刊介绍：
The Iranian Journal of Microbiology (IJM) is an international, multi-disciplinary, peer-reviewed journal that provides rapid publication of the most advanced scientific research in the areas of basic and applied research on bacteria and other micro-organisms, including bacteria, viruses, yeasts, fungi, microalgae, and protozoa concerning the development of tools for diagnosis and disease control, epidemiology, antimicrobial agents, clinical microbiology, immunology, Genetics, Genomics and Molecular Biology. Contributions may be in the form of original research papers, review articles, short communications, case reports, technical reports, and letters to the Editor. Research findings must be novel and the original data must be available for review by the Editors, if necessary. Studies that are preliminary, of weak originality or merely descriptive as well as negative results are not appropriate for the journal. Papers considered for publication must be unpublished work (except in an abstract form) that is not under consideration for publication anywhere else, and all co-authors should have agreed to the submission. Manuscripts should be written in English.
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号
