Storage of Bacteriophages at 4°C Leads to no Loss in Their Titer after One Year

Alvi, Iqbal Ahmad; Asif, Muhammad; Tabassum, Rabia; Abbas, Zaigham; Rehman, Sami Ur

doi:10.17582/journal.pjz/2018.50.6.sc8

Cited by 12 publications

(9 citation statements)

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“…Furthermore, in the present study, the addition of glycerol as a cryopreservative agent at freezing temperatures did not improve the stability of HCF1 (Figure 2). Similar to the present findings, previous studies have shown that storage at 4 • C results in improved stability compared to freezing with glycerol (Clark and Geary, 1973;Alvi et al, 2018).…”

Section: Storage Stabilitysupporting

confidence: 92%

Phenotypic Characterization and Whole-Genome Analysis of a Novel Bacteriophage HCF1 Infecting Citrobacter amalonaticus and C. freundii

2021

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Citrobacter species often occur in sewage, food, soil, wastewater, and in the intestinal tract of animals and humans. Citrobacter spp. cause urinary tract infections (UTIs) and infantile meningitis in humans. Due to the presence of plasmid-encoded resistance genes, Citrobacter spp. are often resistant to many antibiotics. In this study, Citrobacter virus HCF1, a novel virulent bacteriophage capable of killing Citrobacter amalonaticus and Citrobacter freundii, was isolated from the sewage water. The isolated bacteriophage was characterized with respect to transmission electron microscopy, one-step growth curve, host range, in vitro efficacy, storage stability, and environmental stress tolerance. The one-step growth curve analysis revealed that the latent period of HCF1 was 30 min and the estimated burst size was 121 plaque-forming units (PFU) per bacterial cell. Host range testing indicated that the HCF1 was specific to the Citrobacter genus. In vitro efficacy assay in the effluent of an anaerobic biodigester showed that the HCF1 completely eliminated the host within 4 and 5 h at MOI:100 and MOI:10, respectively, thereby indicating its potential for combating C. amalonaticus infections. The isolated bacteriophage is considerably stable and tolerant to environmental stress. Furthermore, the complete genome of HCF1 was sequenced using Oxford Nanopore sequencing and the data were subjected to detailed bioinformatic analyses. NCBI-BLASTn analysis revealed that the HCF1 genome had a query coverage of 15–21% and a maximum similarity of 77.27–78.49% with 11 bacteriophages of the Drexlerviridae family. Detailed bioinformatic analysis of the genome profile suggests that HCF1 is a novel T1svirus belonging to the Tempevirinae subfamily of the Drexlerviridae family.

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Section: Storage Stabilitysupporting

confidence: 92%

Phenotypic Characterization and Whole-Genome Analysis of a Novel Bacteriophage HCF1 Infecting Citrobacter amalonaticus and C. freundii

2021

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“…These characteristics may be helpful in administration of phages in different environment as therapeutic agent. We found that phage present highest storage stability at refrigerator temperature similar to results previously reported [36]. Phage TSP ful lls the ideal parameters of phage therapy that includes short latency period and high burst size.…”

Section: Discussionsupporting

confidence: 88%

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

Tabassum¹,

Alvi²,

Asif³

et al. 2021

Preprint

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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.

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“…Storage stability of tested BaP1 and BaP2 phages depicted that they had maximum stability at 4 o C as they retain their viability up to the 12 months. Although, freezing temperatures were not revealed to be suitable for storage of phages as they lost their viability to 100% after 12month period at -80 o C and 50% at -20 o C. There are several records of bacteriophages stored at 4 o C maintaining their high titer even after 30 years (Fortier and Moineau, 2009;Merabishvili et al, 2009;Weber-Dąbrowska et al, 2016;Alvi et al, 2018). The decrease in phage titer for long term storage might be due to non-availability of host system (host bacterium and media) or absence of suitable cryopreservatives.…”

Section: Discussionmentioning

confidence: 99%

Isolation and Physicochemical Characterization of Brucella Phages

2021

THE JAPS

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Bovine brucellosis, caused by Brucella abortus, is an economically significant bacterial disease causing enormous economic losses in developing countries. Due to emerging antibacterial resistance in current use of antibiotics and insufficient immunity by WHO recommended vaccine strategies, it is recommended to cull the positive animals to control the disease. In such circumstances, use of host specific bacteriophages could be an alternate option to control the disease. In present study, brucellaphages were isolated from slurry samples (n=50) of livestock farms. Seven samples were found positive in spot method, while two samples gave the positive plaques of pinpoint size (0.5 mm) with round and clear appearance in plaque assay. Isolated brucellaphages (BaP1 and BaP2) did not produce plaques against Staphylococcus aureus, Streptococcus, Bacillus, Escherichia coli, Salmonella, and Pasteurella multocida. Physicochemical characterization revealed that lytic activity of phages was present up to 60 o C which started to decrease at 70 o C and maximum stability was between 7 to 9 pH. Exposure of sunlight, normal fluorescent and UV light inactivated these phages within 3 hours, 24 hours and 15 minutes, respectively. Phages become inactivated in 15 minutes when treated with Sodium Dodecyl Sulphate, chloroform, Lysozyme, and Proteinase K, however, no effect of EDTA, normal saline, Trypsin and RNAse was observed on brucellaphages. In conclusion, the results have laid the foundation to standardize practical applications of brucellaphages after detailed in-vitro and in-vivo experimental evaluations.

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Storage of Bacteriophages at 4°C Leads to no Loss in Their Titer after One Year

Cited by 12 publications

References 0 publications

Phenotypic Characterization and Whole-Genome Analysis of a Novel Bacteriophage HCF1 Infecting Citrobacter amalonaticus and C. freundii

Phenotypic Characterization and Whole-Genome Analysis of a Novel Bacteriophage HCF1 Infecting Citrobacter amalonaticus and C. freundii

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

Isolation and Physicochemical Characterization of Brucella Phages

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