Phage phiKZ—The First of Giants

Abstract

The paper covers the history of the discovery and description of phiKZ, the first known giant bacteriophage active on Pseudomonas aeruginosa. It also describes its unique features, especially the characteristic manner of DNA packing in the head around a cylinder-shaped structure (“inner body”), which probably governs an ordered and tight packaging of the phage genome. Important properties of phiKZ-like phages include a wide range of lytic activity and the blue opalescence of their negative colonies, and provide a background for the search and discovery of new P. aeruginosa giant phages. The importance of the phiKZ species and of other giant phage species in practical phage therapy is noted given their broad use in commercial phage preparations.

Two Novel Bacteriophages Control Multidrug- and Methicillin-Resistant Staphylococcus pseudintermedius Biofilm

“…In contrast, upon treatment with high concentrations of phages, bacterial growth was inhibited during the first few hours, after which the bacteria began to grow (Figure 4). This peculiar anti-bacterial effect of phages has been observed in various environments and can be attributed to pseudolysogeny induced by a high MOI phage (49). Pseudolysogeny of virulent phages is considered to provide advantages such as long term survival of their genome in the condition for propagation is not favorable (50,51).…”

“…Pseudolysogeny of virulent phages is considered to provide advantages such as long term survival of their genome in the condition for propagation is not favorable (50,51). This evolutionary characteristic of the pseudolysogeny is a disadvantage for phage therapy with the following flaws: hindrance of other phage-pathogen collision by viscous materials originated from host cell lysis; transduction of antibiotic/phage resistant-, virulence-related genes (49). As a high dose of phage solution is preferable for therapeutic application, it seems like a negative effect that re-growth of the pathogen is observed as a result of pseudolysogeny induction in high MOI groups.…”

“…As a high dose of phage solution is preferable for therapeutic application, it seems like a negative effect that re-growth of the pathogen is observed as a result of pseudolysogeny induction in high MOI groups. And the phages having pseudolysogeny life cycle are not recommended for the therapeutic agent (49,50). However, the antimicrobial effect of two newly isolated phages was superior to the high MOI groups at their low MOI (Figure 4), which can be an economical way to treat the pathogen in case the induction of pseudolysogeny can be prevented.…”

Basics for Improved Use of Phages for Therapy

“…The host is Pseudomonas chlororaphis [ 64 ]. Phage 201phi2-1 is of interest as it is found [ 64 ] to be a homolog of phage ϕKZ, a lytic phage that infects Pseudomonas aeruginosa [ 65 , 66 ], a major pathogen causing respiratory disease [ 67 ].…”

On the potential of microscale electrokinetic cascade devices

“…Current separation and purification techniques for phages are time and labor intensive and involve several complex steps [9]. So-called "giant" or "jumbo" phages (a nontaxonomic term first used in the literature [10][11][12][13] to refer a phage with >200 kilobase pairs in their genome) are especially difficult to work with. The removal of bacterial cells and debris from stocks of these giant phages is normally problematic as clarification using higher centrifugation spins or filtration through membranes (as routinely used for smaller phages) results in a significant reduction of phage yield [10,14].…”