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Periodontitis is a chronic inflammatory condition that can damage soft tissues and supporting teeth. Enterococcus faecalis is an opportunistic pathogen usually living in the oral cavity and plays a critical role in apical periodontitis that significantly threatens human health. The use of bacteriophages as an alternative way to eliminate bacterial infections is a promising approach. E. faecalis was isolated from the depth of dental packets of patients with periodontitis. Antimicrobial susceptibility was tested using 16 antimicrobial agents. Also, a specific virulent bacteriophage (vB_EfaS-SRH2) with an irregular pentagonal morphology of the head and a non-contractile tail belonging to the Siphoviridae, was isolated from wastewater in East of Isfahan, Iran, and its physiological and genomic specifications were investigated. The genome was double-strand DNA with 38,746 bp length and encoded 62 putative ORFs. In addition, eight Anti-CRISPERs and 30 Rho-dependent terminators were found. No tRNA was found. It had a short latent period of 15 min and a large burst size of ~ 125. No undesirable genes (antibiotic resistance, lysogenic dependence, and virulence factors) were identified in the genome. Based on physiological properties and genomic characteristics, this phage can be used as a suitable choice in phage therapy for periodontitis and root canal infection., (© 2022. The Author(s).)

Enterococcus faecalis is an environmental agent of bovine mastitis in cows and has many cytopathic effects on the urinary tract in both humans and animals. In this study, a novel lytic bacteriophage, vB_EfaS-DELF1, was isolated against 21 E. faecalis isolated from bovine mastitis, including vancomycin-resistant E. faecalis (VRE). vB_EfaS-DELF1 bacteriophage was specific for E. faecalis and showed no lytic effects against other tested Enterococcus spp., Gram-negative, or Gram-positive bacteria. Moreover, no activity was observed against yogurt starters. The phage suspension was stable in a wide range of pH, salinity, and temperature. It retained its activity in 3.5 % fat milk. vB_EfaS-DELF1 has the common phenotypic features of Siphoviridae with a double-strand DNA of 40,248 bp in length and a G + C content of 34.9 %. The genome encodes 62 putative ORFs and no tRNA. No undesirable genes such as lysogenic mediators, antibiotic resistance, or virulence factor genes were detected in the genome. The comparative genomic analysis demonstrated similarity to the other available phage genomes. The highest similarity was observed with two other phages (50 % coverage and 82.38 % identities with IME-EFm1; 35 % coverage and 86.22 % identities with IME-EFm5) that were placed in the same clade. The differences with the other aligned phages were high and were placed in distant clusters. Regarding the specificity of this new bacteriophage against all of the tested E. faecalis isolates and, in particular, against the vancomycin-resistant ones, and also the absence of antibiotic resistance or virulence genes in its genome, vB_EfaS-DELF1 is suggested as a potential candidate for biocontrol of E. faecalis infections., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Escherichia coli (E. coli) is one of the most common uropathogenic bacteria. The emergence of multi-drug resistance among these bacteria resulted in a worldwide public health problem which requires alternative treatment approaches such as phage therapy. In this study, phage VB_EcoS-Golestan, a member of Siphoviridae family, with high lytic ability against E. coli isolates, was isolated from wastewater. Its burst size was large and about 100 plaque-forming units/infected cell, rapid adsorption time, and high resistance to a broad range of pH and temperatures. Bioinformatics analysis of the genomic sequence suggests that VB_EcoS-Golestan is a new phage closely related to Escherichia phages in the Kagunavirus genus, Guernseyvirinae subfamily of Siphoviridae. The genome size was 44829 bp bp that encodes 78 putative ORFs, no tRNAs, 7 potential promoter sequences and 13 Rho-factor-independent terminators. No lysogenic mediated genes were detected in VB_EcoS-Golestan genome. Overall VB_EcoS-Golestan might be used as a potential treatment approach for controlling E. coli mediated urinary tract infection, however, further studies are essential to ensure its safety.

Proteus mirabilis is one of the most common causes of complicated urinary tract infections (UTI), especially in catheter-associated UTIs. The increased resistance to antibiotics, among P. mirabilis isolates has led us to search for alternative antibacterial agents. In this study, genome of a lytic Proteus phage VB_PmiS-Isfahan, isolated from wastewater, and active against planktonic and biofilms of P. mirabilis, isolated from UTI, was analyzed. Accordingly, the genome was sequenced and its similarity to other phages was assessed by the Mauve and EasyFig softwares. "One Click" was used for phylogenetic tree construction. The complete genome of VB_PmiS-Isfahan was 54,836 bp, dsDNA with a G+C content of 36.09%. Nighty-one open reading frames (ORFs) was deduced, among them, 23 were considered as functional genes, based on the homology to the previously characterized proteins. The BLASTn of VB_PmiS-Isfahan showed low similarity to complete genome of Salmonella phages VB_SenS_Sasha, 9NA, and VB_SenS-Sergei. A comparison of Nucleic acid and amino acid sequence, and phylogenetic analyses indicated that the phage is novel, significantly differs, and is distant from other genera, within Siphoviridae family. No virulence-associated and antibiotic resistance genes were detected. Thus, VB_PmiS-Isfahan phage is suggested as a potential novel candidate for the treatment of diseases, caused by P. mirabilis., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Shigella dysenteriae is one of the members of Shigella genus which was the main responsible of different Shigellosis outbreaks worldwide. The increasing consumption of antibiotics has led to the emergence and spreading of antibiotic-resistant strains. Therefore, finding new alternatives for infection control is essential, one of which is using bacteriophages., Materials and Methods: Lytic bacteriophage against Shigella dysenteriae was isolated from petroleum refinery wastewater. Phage morphological and genetic characteristics were studied using TEM, and sequencing, respectively. In addition, the genome size was estimated, and phage resistance to different temperatures and pH, host range, adsorption rate, and one-step growth were investigated., Results: According to the morphology and genetic results, this phage was named vB-SdyS-ISF003. Sequencing of the PCR products revealed that the vB-SdyS-ISF003 phage belongs to the species T1virus, subfamily Tunavirinae of family Siphoviridae. This was the first detected bacteriophage against S. dysenteriae, which belongs to the family Siphoviridae. In addition, its host range was limited to S. dysenteriae. The genome size was about 62 kb. vB-SdyS-ISF003 phage has a number of desirable characteristics including the limited host range to S. dysenteriae, very short connection time, a relatively wide range of temperature tolerance -20 to 50 °C, pH tolerance of 7-9 without significant reduction in the phage titer., Conclusion: vB-SdyS-ISF003 is a novel virulent T1virus phage and has the appropriate potential for being used in bio controlling of S. dysenteriae in different condition., (Copyright © 2019. Published by Elsevier Ltd.)

Antibiotic resistance is increasing among Staphylococcus saprophyticus strains isolated from urinary tract infection. This necessitates alternative therapies. For this, a lytic phage (vB_SsapS-104) against S. saprophyticus, which formed round and clear plaques on bacterial culture plates, was isolated from hospital wastewater and characterized. Microscopy analysis showed that it had a small head (about 50 nm), tail (about 80 nm), and a collar (about 22 nm in length and 19 nm in width) indicating to be a phage within Siphoviridae family. Phage vB_SsapS-104 showed a large latency period of about 40 min, rapid adsorption rate that was significantly enhanced by MgCl 2 and CaCl 2 , and high stability to a wide range of temperatures and pH values. Restriction analyses demonstrated that phage consists of a double-stranded DNA with an approximate genome size of 40 Kb. BLAST results did not show high similarity (megablast) with other previously identified phages. But, in Blastn, similarity with Staphylococcus phages was observed. Phage vB_SsapS-104 represented high anti-bacterial activity against S. saprophyticus isolates in vitro as it was able to lyse 8 of the 9 clinical isolates (%88.8) obtained from a hospital in Gorgan, Iran. It was a S. saprophyticus-specific phage because no lytic activity was observed on some other pathogenic bacteria tested. Therefore, phage vB_SsapS-104 can be considered as a specific virulent phage against of S. saprophyitcus isolated from urinary tract infection. This study provided the partial genomic characterization of S. saprophyticus phage and its application against urinary tract infection associated with S. saprophyticus. This phage also can be considered as a good candidate for a therapeutic alternative in the future.

Purpose: Shigellosis is one of the most important food-borne and water-borne diseases worldwide. Although antibiotics are considered as efficient agents for shigellosis treatment, improper use of these has led to the emergence of antibiotic-resistant Shigella spp. Therefore, finding a new strategy as alternative treatment seems necessary., Methodology: Different samples from a wastewater treatment plant were used to isolate Shigella spp. specific phages. Physiological properties were determined, and genomic analysis was also carried out., Results: A virulent Siphoviridae bacteriophage, vB_SsoS-ISF002, was isolated from urban wastewater in Iran and showed infectivity to different isolates of both Shigella sonnei and Shigella flexneri. vB_SsoS-ISF002 was stable at different pH values and temperatures. It had a short latent period (15 min), a large burst size (76±9 p.f.u. cell -1 ) and appropriate lytic activity especially at high MOI. Its genome (dsDNA) was 50 564 bp with 45.53 % GC content and 76 predicted open reading frames. According to comparative genomic analysis and phylogenic tree construction, vB_SsoS-ISF002 was considered as a member of the T1virus genus., Conclusion: These results indicated that vB_SsoS-ISF002 is a novel virulent T1virus phage and may have potential as an alternative treatment for shigellosis.