TAC1, an unclassified bacteriophage of the family Myoviridae infecting Acinetobacter baumannii with a large burst size and a short latent period

2019 ◽  
Vol 165 (2) ◽  
pp. 419-424 ◽  
Author(s):  
Muhammad Asif ◽  
Iqbal Ahmad Alvi ◽  
Rabia Tabassum ◽  
Shafiq Ur Rehman
Keyword(s):  
Latent Period ◽  
Acinetobacter Baumannii ◽  
Burst Size ◽  
Short Latent Period ◽  
The Family ◽  
Large Burst

scholarly journals TSP, a virulent Podovirus can control the growth of Staphylococcus aureus till 12 hours

2021 ◽  
Author(s):  
Rabia Tabassum ◽  
Iqbal Ahmed Alvi ◽  
Muhammad Asif ◽  
Abdul Basit ◽  
Shafiq ur Rehman
Keyword(s):  
Staphylococcus Aureus ◽  
Latent Period ◽  
Genome Sequence ◽  
Burst Size ◽  
Gc Content ◽  
Comparative Genomic ◽  
Broad Host Range ◽  
Lytic Bacteriophage ◽  
Short Latent Period ◽  
Promising Therapeutic Approach

Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is a prevailing nosocomial pathogen that causes a large number of diseases in healthcare and community settings. The MRSA causes infections in different tissues of immunocompromised individuals leading to increased morbidity and mortality. It possess various virulence mechanisms to show resistance against to a lot of beta-lactam antibiotics. To tackle this emerging issue of MRSA, there is an urgent need of antibiotic alternatives and utilizing lytic bacteriophages is one of the best promising therapeutic approach. In the present study, a lytic bacteriophage TSP was isolated from hospital wastewater against MRSA. Its morphology, physiology, host specificity, burst size and lytic spectrum were determined and complete genome sequence was analyzed. TSP phage efficiently inhibit bacterial growth for up to 12 hours. TSP phage showed broad lytic spectrum against clinical isolates of MRSA (78%) and MSSA (37%). It showed stability at varying temperatures (25ºC, 37ºC) and pH (5–9), while its maximum storage stability was observed at 4ºC. It had short latent period (20min) and high burst size (103 PFU/ infected cell). TSP genome sequence and restriction analysis revealed that its genome is linear having 17,987 bp in length with an average GC content of 29.7%. The TSP genome showed 98% similarity to S aureus phages SCH1, SCH11 and vB SauP-436A1. According to comparative genomic analysis and phylogenetic tree analysis, TSP phage can be considered as a member of genus “P68viruses”. The strong lytic activity, broad host range and short latent period along with absence of any lysogenic and toxic genes make TSP a very good candidate for phage therapy against MRSA infections if prove safe during in vivo studies.

scholarly journals Lytic Myophage Abp53 Encodes Several Proteins Similar to Those Encoded by Host Acinetobacter baumannii and Phage phiKO2

2011 ◽  
Vol 77 (19) ◽  
pp. 6755-6762 ◽  
Author(s):  
Chia-Ni Lee ◽  
Tsai-Tien Tseng ◽  
Juey-Wen Lin ◽  
Yung-Chieh Fu ◽  
Shu-Fen Weng ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Burst Size ◽  
Sputum Sample ◽  
Polyacrylamide Gel Electrophoresis ◽  
Multiple Drug ◽  
Lytic Phage ◽  
Tail Fiber ◽  
Drug Resistant ◽  
Content Type ◽  
Multiple Drug Resistant

ABSTRACTAcinetobacter baumanniiis an important Gram-negative opportunistic pathogen causing nosocomial infections. The emergence of multiple-drug-resistantA. baumanniiisolates has increased in recent years. Directed toward phage therapy, a lytic phage ofA. baumannii, designated Abp53, was isolated from a sputum sample in this study. Abp53 has an isometric head and a contractile tail with tail fibers (belonging toMyoviridae), a latent period of about 10 min, and a burst size of approximately 150 PFU per infected cell. Abp53 could completely lyse 27% of theA. baumanniiisolates tested, which were all multiple drug resistant, but not other bacteria. Mg2+enhanced the adsorption and productivity of, and host lysis by, Abp53. Twenty Abp53 virion proteins were visualized in SDS-polyacrylamide gel electrophoresis, with a 47-kDa protein being the predicted major capsid protein. Abp53 has a double-stranded DNA genome of 95 kb. Sequence analyses of a 10-kb region revealed 8 open reading frames. Five of the encoded proteins, including 3 tail components and 2 hypothetical proteins, were similar to proteins encoded byA. baumanniistrain ACICU. ORF1176 (one of the tail components, 1,176 amino acids [aa]), which is also similar to tail protein gp21 ofKlebsiellaphage phiKO2, contained repeated domains similar to those within the ACICU_02717 protein ofA. baumanniiACICU and gp21. These findings suggest a common ancestry and horizontal gene transfer during evolution. As phages can expand the host range by domain duplication in tail fiber proteins, repeated domains in ORF1176 might have a similar significance in Abp53.

scholarly journals Evaluation of the Efficacy of a Bacteriophage in the Treatment of Pneumonia Induced by Multidrug ResistanceKlebsiella pneumoniaein Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Fang Cao ◽  
Xitao Wang ◽  
Linhui Wang ◽  
Zhen Li ◽  
Jian Che ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Burst Size ◽  
Multidrug Resistant ◽  
Lung Lesion ◽  
Lytic Bacteriophage ◽  
Short Latent Period ◽  
Dose Dependent ◽  
Antibiotic Control

Multidrug-resistantKlebsiella pneumoniae(MRKP) has steadily grown beyond antibiotic control. However, a bacteriophage is considered to be a potential antibiotic alternative for treating bacterial infections. In this study, a lytic bacteriophage, phage 1513, was isolated using a clinical MRKP isolate KP 1513 as the host and was characterized. It produced a clear plaque with a halo and was classified as Siphoviridae. It had a short latent period of 30 min, a burst size of 264 and could inhibit KP 1513 growthin vitrowith a dose-dependent pattern. Intranasal administration of a single dose of 2 × 109 PFU/mouse 2 h after KP 1513 inoculation was able to protect mice against lethal pneumonia. In a sublethal pneumonia model, phage-treated mice exhibited a lower level ofK. pneumoniaeburden in the lungs as compared to the untreated control. These mice lost less body weight and exhibited lower levels of inflammatory cytokines in their lungs. Lung lesion conditions were obviously improved by phage therapy. Therefore, phage 1513 has a great effectin vitroandin vivo, which has potential to be used as an alternative to an antibiotic treatment of pneumonia that is caused by the multidrug-resistantK. pneumoniae.

Host-parasite relationships in bean cultivars of varying susceptibility to bean rust

2000 ◽  
Vol 77 (11) ◽  
pp. 1551-1559 ◽  
Author(s):  
M W Harding ◽  
J C Stutz ◽  
R W Roberson
Keyword(s):  
Phaseolus Vulgaris ◽  
Latent Period ◽  
Rust Fungus ◽  
Freeze Substitution ◽  
Infected Leaf ◽  
Bean Rust ◽  
Infection Efficiency ◽  
Host Cytoplasm ◽  
Short Latent Period ◽  
Host Parasite

Components of disease development were measured in three cultivars of Phaseolus vulgaris L. (common bean) infected with Uromyces appendiculatus (Pers.:Pers.) Unger (bean rust fungus) race O. Disease measurements and light and electron microscope data of host-parasite relationships were obtained and analyzed. Uredinial size, infection efficiency, latent period, and fungal colony radius were measured from infected bean leaves that were grown under controlled conditions. Phaseolus vulgaris cultivar Pinto 111, a highly susceptible check, displayed the largest uredinia, the highest infection efficiency, large colony radii, and a short latent period. Cultivars Early Gallatin and Kentucky Wonder (K.W.) 814 displayed moderate and low susceptibility, respectively. Cultivar Early Gallatin had smaller uredinia, reduced infection efficiency, and longer latent period when compared with cv. Pinto 111. Cultivar K.W. 814 was characterized by minute pustules, restricted colony expansion, and the longest latent period. Ultrastructural data of host-parasite relationships were collected from infected leaf tissues and prepared for transmission electron microscopy by high-pressure cryofixation and freeze substitution. In 'Pinto 111' the collars around haustorial necks were composed of a fibrillar network embedded in an electron transparent matrix. Ultrastructural observations indicated that Cultivars K.W. 814 and Early Gallatin deposited more collar material than 'Pinto 111.' Networks of tubular endomembranes developed near the host-parasite interface in the host cytoplasm of cultivars K.W. 814 and Early Gallatin. The tubules showed continuity with the extrahaustorial membrane and contained an amorphous, electron-dense material in the lumen. Tubular endomembranes were not seen in the highly susceptible cultivar Pinto 111.

scholarly journals Identification and Functional Analysis of Temperate Siphoviridae Bacteriophages of Acinetobacter baumannii

Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 604 ◽  
Author(s):  
Shimaa Badawy ◽  
Maria I. Pajunen ◽  
Johanna Haiko ◽  
Zakaria A. M. Baka ◽  
Mohamed I. Abou-Dobara ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Trna Gene ◽  
Phage Therapy ◽  
Morphological Characteristics ◽  
Opportunistic Pathogen ◽  
Clinical Strains ◽  
Narrow Host Range ◽  
Clinical Challenge ◽  
Transmission Electron ◽  
The Family

Acinetobacter baumannii is an opportunistic pathogen that presents a serious clinical challenge due to its increasing resistance to all available antibiotics. Phage therapy has been introduced recently to treat antibiotic-incurable A. baumannii infections. In search for new A. baumannii specific bacteriophages, 20 clinical A. baumannii strains were used in two pools in an attempt to enrich phages from sewage. The enrichment resulted in induction of resident prophage(s) and three temperate bacteriophages, named vB_AbaS_fEg-Aba01, vB_AbaS_fLi-Aba02 and vB_AbaS_fLi-Aba03, all able to infect only one strain (#6597) of the 20 clinical strains, were isolated. Morphological characteristics obtained by transmission electron microscopy together with the genomic information revealed that the phages belong to the family Siphoviridae. The ca. 35 kb genomic sequences of the phages were >99% identical to each other. The linear ds DNA genomes of the phages contained 10 nt cohesive end termini, 52–54 predicted genes, an attP site and one tRNA gene each. A database search revealed an >99% identical prophage in the genome of A. baumannii strain AbPK1 (acc. no. CP024576.1). Over 99% identical prophages were also identified from two of the original 20 clinical strains (#5707 and #5920) and both were shown to be spontaneously inducible, thus very likely being the origins of the isolated phages. The phage vB_AbaS_fEg-Aba01 was also able to lysogenize the susceptible strain #6597 demonstrating that it was fully functional. The phages showed a very narrow host range infecting only two A. baumannii strains. In conclusion, we have isolated and characterized three novel temperate Siphoviridae phages that infect A. baumannii.

scholarly journals Characterization of a Novel Bacteriophage Henu2 and Evaluation of the Synergistic Antibacterial Activity of Phage-Antibiotics

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 174
Author(s):  
Xianghui Li ◽  
Tongxin Hu ◽  
Jiacun Wei ◽  
Yuhua He ◽  
Abualgasim Elgaili Abdalla ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Burst Size ◽  
Open Reading Frames ◽  
Comparative Genomic ◽  
Sewage Sample ◽  
Bacterial Killing ◽  
Wide Range ◽  
The Family ◽  
Infected Cells

Staphylococcus aureus phage Henu2 was isolated from a sewage sample collected in Kaifeng, China, in 2017. In this study, Henu2, a linear double-stranded DNA virus, was sequenced and found to be 43,513 bp long with 35% G + C content and 63 putative open reading frames (ORFs). Phage Henu2 belongs to the family Siphoviridae and possesses an isometric head (63 nm in diameter). The latent time and burst size of Henu2 were approximately 20 min and 7.8 plaque forming unit (PFU)/infected cells. The Henu2 maintained infectivity over a wide range of temperature (10–60 °C) and pH values (4–12). Phylogenetic and comparative genomic analyses indicate that Staphylococcus aureus phage Henu2 should be a new member of the family of Siphoviridae class-II. In this paper, Phage Henu2 alone exhibited weak inhibitory activity on the growth of S. aureus. However, the combination of phage Henu2 and some antibiotics or oxides could effectively inhibit the growth of S. aureus, with a decrease of more than three logs within 24 h in vitro. These results provide useful information that phage Henu2 can be combined with antibiotics to increase the production of phage Henu2 and thus enhance the efficacy of bacterial killing.

scholarly journals Characterization of E coli phage isolated from sewage

2010 ◽  
Vol 9 (2) ◽  
pp. 45 ◽  
Author(s):  
G.A. Al-Mola, and I. H. Al-Yassari
Keyword(s):  
Statistical Analysis ◽  
Latent Period ◽  
Burst Size ◽  
Host Cells ◽  
Effect Of Temperature ◽  
Lytic Bacteriophage ◽  
Bacterial Cells ◽  
Dilution Factor ◽  
Countable Number ◽  
Phage Titre

Bacteriophage are viruses that infect bacterial cells. as with all viruses, phage are nonliving agents and thus require the use of the host‟s metabolic processes to replicate itself. in this study, the phage of interest are those that infect and lyses E. colt host cells. when phage are released from the ruptured host, distinct zones of clearing (plaques) form. the original E. colt host cells for this experiment came from a sample of raw sewage. in order to obtain the bacteriophage, a procedure of enrichment, isolation, dilution and seeding was followed, the presence of distinct plaques indicated that lytic bacteriophage had been successfully amplified, separated and grown.This study included determination of phage titre, latent period , rise period and the burst size of the phage and effect some of factor on phage titre such as (temperature, ether and chloroform) .for determination ofhage titre used series of dilutions(10-1, 10-2, 10-3, 10-4, 10-4, 10-6, 10-7, 10-8, 10-9) the dilution factor gave the best countable number of plaques is(103). this dilution factor was then used for all other experiments, the latent period , rise period and the burst size of the phage are determined by countable number of plaques and phage titre(titer: plaque-forming unit(p.f.u) during 10,20,30,40,50, and 60 minutes . it was (4.7x105 „ 5.3x105 and 6.0x105)during 1O,20and30minutes respectively in the latent period ,but it was (8.5x105 8.9x10‟ 9.3x105)during 40,50,and 60 minutes respectively in the rise period .then the burst size of the phage is counted by the ratio of the phage titer after rise period to that during the latent period it was(1.67).This study also included effect of temperature on phage titre the statistical analysis was significantly increase P<0.05 in phage titre at the temperature37 C° comparing with phage titre at the temperature 50 C° and phage titre at the temperature 65 C°. effects of ether and chloroform on number of plaques and phage titre during 5,10,15 ,20,25 ,30,35 and 40 minutes it was(0.7x105 , 0.3x105 , 0 , 0 , 0 , 0, 0 and 0) respectively in ether sensitivity, but the phage titre in chloroform sensitivity was completely inactivated by chloroform treatment, the statistical analysis (freedom degree ( 2,21 ) and F value=52.60 was high] significant increase (P<0.05) in phage titre in normal saline comparing with phage titre in ether and chloroform sensitivity

scholarly journals Host traits drive viral life histories across phytoplankton viruses

2017 ◽  
Author(s):  
Kyle F. Edwards ◽  
Grieg F. Steward
Keyword(s):  
Latent Period ◽  
Genome Size ◽  
Life Histories ◽  
Burst Size ◽  
Evolutionary Model ◽  
Viral Control ◽  
Ecosystem Impacts ◽  
Community Processes ◽  
Size Growth ◽  
Host Metabolism

AbstractViruses are integral to ecological and evolutionary processes, but we have a poor understanding of what drives variation in key traits across diverse viruses. For lytic viruses, burst size, latent period, and genome size are primary characteristics controlling host-virus dynamics. Burst size and latent period are analogous to organismal traits of fecundity and generation time, and genome size affects the size of the virion as well as viral control of host metabolism. Here we synthesize data on these traits for 75 strains of phytoplankton viruses, which play an important role in global biogeochemistry. We find that primary traits of the host (genome size, growth rate) are major ecological drivers, explaining 40-50% of variation in burst size and latent period. We analyze an eco-evolutionary model to explore mechanisms underlying these patterns. We find that burst size may be set by the host genomic resources available for viral construction, while latent period evolves to permit this maximal burst size, modulated by host metabolic rate. These results suggest that general mechanisms may underlie the evolution of diverse viruses, which will facilitate our understanding of viral community processes, ecosystem impacts, and coevolutionary dynamics.

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