Effect of various bacteriological media on the plaque morphology of Staphylococcus and Vibrio phages

Nachimuthu, Ramesh; Loganathan, Archana; Royam, Madhav Madurantakam; Manohar, Prasanth; Eniyan, Kandasamy

doi:10.1099/acmi.0.000036

Cited by 16 publications

(11 citation statements)

References 8 publications

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“…However, plaque morphology can vary greatly depending on a variety of factors, including the growth medium used and the physiological state of the bacterial host (Ramesh et al, 2019). Delayed or substandard bactericidal activity in bacterial growth assays can also serve as an indicator, but their interpretation is not always clear-cut.…”

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confidence: 99%

Screening for Lysogen Activity in Therapeutically Relevant Bacteriophages

Altamirano¹,

Barr²

2021

BIO-PROTOCOL

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Lysogenic phages can integrate into their bacterial host's genome, potentially transferring any genetic information they possess including virulence or resistance genes, and are therefore routinely excluded from therapeutic applications. Lysogenic behavior is typically seen in phages that create turbid plaques or possess subpar bactericidal activity; yet, these are not definitive indicators. As a result, the presence of integrase genes is often used as a hallmark for lysogenic behavior; however, the accuracy of genetic screening for lysogeny depends on the quality of the extraction, sequencing and assembly of the phage genome, and database comparison. The present protocol describes a simple phenotypic test that can be used to screen therapeutically relevant phages for lysogenic behavior. This test relies on the identification of spontaneous phage release from their lysogenized host and can be reliably used in cases where no sequencing data are available. The protocol does not require specialized equipment, is not work-intensive, and is broadly applicable to any phage with an easily culturable bacterial host, making it particularly amenable to settings with limited resources.

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confidence: 99%

Screening for Lysogen Activity in Therapeutically Relevant Bacteriophages

Altamirano¹,

Barr²

2021

BIO-PROTOCOL

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“…Since the predicted lifestyle of MLP2 is to carry out lytic cycles ( Fig. 1A ), the turbid plaques observed might have been a consequence of an impaired/impeded ability to generate plaques mediated by the composition of the medium, as has been demonstrated for other phages ( 39 ), or by bacterial glycosylation of LPS, which has been proposed as a mechanism that may impact cell sensitivity to phages ( 40 ). In the case of UTI-89 and UPEC 1007, we were not able to determine isolated PFU after MLP2 infection, which might be attributed to an LB agar-dependent interference in the ability of MLP2 to generate plaques, as was mentioned above.…”

Section: Resultsmentioning

confidence: 85%

Isolation and Characterization of Novel Lytic Phages Infecting Multidrug-Resistant Escherichia coli

et al. 2022

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“…2016), phage tolerance (Tzipilevich et al . 2021) and variation of media or growth conditions (Ramesh et al . 2019).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Novel Recombinant Mycobacteriophages derived from Homologous Recombination between two Temperate Phages

Mohammed

Mageeney

Korenberg

et al. 2022

Preprint

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Comparative analyses of mycobacteriophage genomes reveal extensive genetic diversity in genome organization and gene content, contributing to widespread mosaicism. We previously reported that the prophage of mycobacteriophage Butters (cluster N) provides defense against infection by Island3 (subcluster I1). To explore the anti-Island3 defense mechanism, we attempted to isolate Island3 defense escape mutants on a Butters lysogen, but only uncovered phages with recombinant genomes comprised of regions of Butters and Island3 arranged from left arm to right arm as Butters-Island3-Butters (BIBs). Recombination occurs within two distinct homologous regions that encompass lysin A, lysin B, and holin genes in one segment, and RecE and RecT genes in the other. Structural genes of mosaic BIB genomes are contributed by Butters while the immunity cassette is derived from Island3. Consequently, BIBs are morphologically identical to Butters (as shown by transmission electron microscopy) but are homoimmune with Island3. A reverse experiment where an Island3 lysogen was infected with Butters yielded Butters phages and no recombinants, demonstrating directionality to the recombination phenomenon. Recombinant phages overcome antiphage defense and silencing of the lytic cycle. We leverage this observation to propose a stratagem to generate novel phages for therapeutic use.

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Effect of various bacteriological media on the plaque morphology of Staphylococcus and Vibrio phages

Cited by 16 publications

References 8 publications

Screening for Lysogen Activity in Therapeutically Relevant Bacteriophages

Screening for Lysogen Activity in Therapeutically Relevant Bacteriophages

Isolation and Characterization of Novel Lytic Phages Infecting Multidrug-Resistant Escherichia coli

Characterization of Novel Recombinant Mycobacteriophages derived from Homologous Recombination between two Temperate Phages

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