The Effect of Proteolytic Enzymes on <i>E. coli</i> Phages and on Native Proteins

Northrop, John H.

doi:10.1085/jgp.48.1.73

Cited by 12 publications

(5 citation statements)

References 9 publications

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“…Phages in the current study were also stable at a wide pH range (1–11) compared to the phages in other studies [ 49 , 60 ]. Niu et al [ 49 ] revealed that at pH 3 the titer of E. coli O157:H7 phage, AKFV33, dropped by 1.9 logs PFU mL −1 after 15 min and was undetectable after 2 h. In the current study, 3 of the 7 phages survived at pH 1, while all phages survived at pH 2 and 5 after 24 h, with minimal loss in viability.…”

Section: Discussionsupporting

confidence: 54%

Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

Litt

Jaroni

2017

International Journal of Microbiology

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Bacteriophages, recovered from beef cattle environment and specifically targeting Escherichia coli O157:H7, were examined for their physiological and morphological characteristics. Degree of bacterial lysis and host range of isolated bacteriophages was determined against 55 isolates of E. coli O157:H7. Morphology of phages was examined under transmission electron microscope. Phage growth parameters, particularly rate of adsorption, rise period, latent period, and burst size were also determined. The stability of isolated phages was tested at acidic and alkaline pH, at high temperatures, and in cold storage. A total of 7 phages were isolated which showed lytic activity against 50 out of 55 isolates of E. coli O157:H7. Based on the morphology, phages were classified into Myoviridae or Siphoviridae family. Phages had a rise period between 19 and 40 min, a short latent period between 12 and 30 min, and a large burst size (89–631 virions per infected cell), indicating high lytic activity. Phages remained stable for 24 h at a wide pH (1–11) and temperature range (40–60°C) and for 90 d in cold storage. Characterization of bacteriophages, with a diverse host range of E. coli O157:H7, could aid in the development of effective biocontrol strategies for this pathogen in the food industry.

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Section: Discussionsupporting

confidence: 54%

Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

Litt

Jaroni

2017

International Journal of Microbiology

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“…Yamaki et al, 2014 observed that Myoviridae phages drastically lost phage activity (3.5 logs PFU mL − 1 ) after 60 min of incubation at 60°C. However, in the current study, the four phages show stability at temperature of 45 o C to 60 o C while there is no visible plaque observed at temperature above 60 o C. This is in line with the research work of Litt and Jaroni, 2017 on the isolation and physiomorphological characterization of Escherichia coli O157: H7-infecting bacteriophages recovered from beef cattle operations, where the phages remained stable for 24 h at a temperature range (40-60°C) and for 90 days in cold storage.At a wide pH range (2-9), phages in the current study were also stable compared to the phages in other studies(Niu et al, 2012;Northrop, 1964).Niu et al,…”

supporting

confidence: 58%

Characterization of Lytic Phages Isolated from Effluent Water and Soil against E. coli O157:H7

Ngene

Egbere

Onyimba

et al. 2022

Preprint

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Escherichia coli O157:H7 commensally lives in the rumen of food animals, making it an important foodborne pathogen. It can be transmitted through direct and indirect contact with animals or manure of animals carrying E. coli O157:H7, mediating its transfer to water and food products, which could cause infections to human upon consumption. E. coli O157:H7 is currently an emerging food-borne pathogen of severe public health concern. To this effect, bacteriophages can provide alternative measures for its control. This study was aimed at isolation and characterization of lytic phages isolated from effluent water and soil against E. coli O157:H7 as potential biocontrol agents. Fifty environmental bacteria and four phages were isolated from six different locations; Student Village Hostel_1and 2, Old JUTH_1and 2 and Angwa Rukuba_1 and 2 and were examined for their physiological and morphological characteristics. The fifty environmental bacteria isolates were characterized and screened to determine the permissive host for the four phages as the antibiotics susceptibility profile of the environmental isolates were determined. Three isolates EIA_18 (Escherichia coli), EIA_19 (Bacillus spp) and EIA_26 (Pseudomonas aeruginosa) were observed to be permissive host for the phages. The phages were screened against E. coli O157:H7 and other eleven selected pathogenic bacteria. The four phages displayed broad lytic activity against shiga toxin-producing E. coli O157:H7 and some of the selected pathogenic bacteria. These four lytic phages were designated as ECPA_1, ECPA_2, ECPA_3 and ECPA_4. Despite isolation from different locations, further characterization showed that they displayed a high degree of similarities. While all the phages were relatively stable over a wide range of salinity, temperatures, NaCl, Chloroform and pH values, their range of infectivity or lytic profile was rather wide against E. coli O157:H7 and some of the selected pathogenic bacteria, while few of the selected pathogenic bacteria showed no activity. This study showed that the isolated bacteriophages are the dominant E. coli O57:H7-infecting phages harboured in the selected areas within Jos metropolis and due to their favourable characteristics can be exploited in the formulation of phage cocktails for the bio-control of E. coli O157:H7.

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“…Experimental data available so far suggest, however, that bacteriophages demonstrate limited sensitivity to digestive enzymes (e.g., trypsin), but this differs between phage types. Notably, other proteases, such as proteinase K or papain, can easily inactivate phages resistant to trypsin (218)(219)(220)(221)(222)(223). Unfortunately, so far there are no experimental reports available to assess the effects exerted on phages specifically by tissue proteases or those enzymes secreted onto the mucosal surfaces of the lungs.…”

Section: Clearance Of Phages From Bodiesmentioning

confidence: 99%

Pharmacologically Aware Phage Therapy: Pharmacodynamic and Pharmacokinetic Obstacles to Phage Antibacterial Action in Animal and Human Bodies

Dąbrowska

Abedon

2019

Microbiol Mol Biol Rev

136

154

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SUMMARY The use of viruses infecting bacteria (bacteriophages or phages) to treat bacterial infections has been ongoing clinically for approximately 100 years. Despite that long history, the growing international crisis of resistance to standard antibiotics, abundant anecdotal evidence of efficacy, and one successful modern clinical trial of efficacy, this phage therapy is not yet a mainstream approach in medicine. One explanation for why phage therapy has not been subject to more widespread implementation is that phage therapy research, both preclinical and clinical, can be insufficiently pharmacologically aware. Consequently, here we consider the pharmacological obstacles to phage therapy effectiveness, with phages in phage therapy explicitly being considered to serve as drug equivalents. The study of pharmacology has traditionally been differentiated into pharmacokinetic and pharmacodynamic aspects. We therefore separately consider the difficulties that phages as virions can have in traveling through body compartments toward reaching their target bacteria (pharmacokinetics) and the difficulties that phages can have in exerting antibacterial activity once they have reached those bacteria (pharmacodynamics). The latter difficulties, at least in part, are functions of phage host range and bacterial resistance to phages. Given the apparently low toxicity of phages and the minimal side effects of phage therapy as practiced, phage therapy should be successful so long as phages can reach the targeted bacteria in sufficiently high numbers, adsorb, and then kill those bacteria. Greater awareness of what obstacles to this success generally or specifically can exist, as documented in this review, should aid in the further development of phage therapy toward wider use.

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The Effect of Proteolytic Enzymes on E. coli Phages and on Native Proteins

Cited by 12 publications

References 9 publications

Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

Isolation and Physiomorphological Characterization ofEscherichia coliO157:H7-Infecting Bacteriophages Recovered from Beef Cattle Operations

Characterization of Lytic Phages Isolated from Effluent Water and Soil against E. coli O157:H7

Pharmacologically Aware Phage Therapy: Pharmacodynamic and Pharmacokinetic Obstacles to Phage Antibacterial Action in Animal and Human Bodies

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