Table of Contents

Volume 1, Issue 2

  March/April 2011

  Pages 55 - 114

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EDITOR'S CORNER

Open Access Article

d’Hérelle. Preparation of Therapeutic Bacteriophages, Appendix 1 from: Le Phénomène de la Guérison dans les maladies infectieuses: Masson et Cie, 1938, Paris—OCLC 5784382

Sarah J. Kuhl and Hubert Mazure
Pages 55 - 65
http://dx.doi.org/10.4161/bact.1.2.15680
Abstract | PDF


Translated into English by Sarah J. Kuhl and Hubert Mazure




REVIEW

Open Access Article

Phage treatment of human infections

Stephen T. Abedon, Sarah J. Kuhl, Bob G. Blasdel and Elizabeth Martin Kutter
Pages 66 - 85
http://dx.doi.org/10.4161/bact.1.2.15845
Abstract | PDF

Phages as bactericidal agents have been employed for 90 years as a means of treating bacterial infections in humans as well as other species, a process known as phage therapy. In this review we explore both the early historical and more modern use of phages to treat human infections. We discuss in particular the little-reviewed French early work, along with the Polish, US, Georgian and Russian historical experiences. We also cover other, more modern examples of phage therapy of humans as differentiated in terms of disease. In addition, we provide discussions of phage safety, other aspects of phage therapy pharmacology, and the idea of phage use as probiotics.




BASIC RESEARCH PAPERS

Open Access Article

Enumeration of bacteriophage particles: Comparative analysis of the traditional plaque assay and real-time QPCR- and NanoSight-based assays

Bradley Anderson, Mohammed H. Rashid, Chandi Carter, Gary Pasternack, Chythanya Rajanna, Tamara Revazishvili, Timothy Dean, Andre Senecal and Alexander Sulakvelidze
Pages 86 - 93
http://dx.doi.org/10.4161/bact.1.2.15456
Abstract | PDF

Bacteriophages are increasingly being utilized and considered for various practical applications, ranging from decontaminating foods and inanimate surfaces to human therapy; therefore, it is important to determine their concentrations quickly and reliably. Traditional plaque assay (PA) is the current “gold standard” for quantitating phage titers. However, it requires at least 18 h before results are obtained, and they may be significantly influenced by various factors. Therefore, two alternative assays based on the quantitative real-time polymerase chain reaction (QPCR) and NanoSight Limited (NS) technologies were recently proposed for enumerating phage particles. The present study compared the three approaches’ abilities to quantitate Listeria monocytogenes-, Escherichia coli O157:H7-, and Yersinia pestis-specific lytic phages quickly and reproducibly. The average coefficient of variation (CVS) of the PA method including all three phages was 0.15. The reproducibility of the PA method decreased dramatically when multiple investigators performed the assays, and mean differences of as much as 0.33 log were observed. The QPCR method required costly equipment and the synthesis of phage-specific oligonucleotide primers, but it determined phage concentrations faster (within about 4 h) and more precisely than did PA (CVS = 0.13). NS technology required costly equipment, was less precise (CVS = 0.28) than the PA and QPCR methods, and only worked when the phages were suspended in clear medium. However, it provided results within 5 min. After the overall correlation is established with the PA method, either of the two assays may be useful for quickly and reproducibly determining phage concentrations.

Open Access Article

Bacteriophage biocontrol of Listeria monocytogenes on soft ripened white mold and red-smear cheeses

Susanne Guenther and Martin J. Loessner
Pages 94 - 100
http://dx.doi.org/10.4161/bact.1.2.15662
Abstract | PDF

Soft-ripened cheeses belong to the type of food most often contaminated with Listeria monocytogenes, and they have been implicated in several outbreaks of listeriosis. Bacteriophages represent an attractive way to combat foodborne pathogens without affecting other properties of the food. We used the broad host range, virulent Listeria phage A511 for control of L. monocytogenes during the production and ripening phases of both types of soft-ripened cheeses, white mold (Camembert-type) cheese, as well as washed-rind cheese with a red-smear surface (Limburger-type). The surfaces of young, unripened cheese were inoculated with 10¹ - 10³ cfu/cm² L. monocytogenes strains Scott A (serovar 4b) or CNL 103/2005 (serovar 1/2a). Phage was applied at defined time points thereafter, in single or repeated treatments, at 3 × 10⁸ or 1 × 10⁹ pfu/cm². With Scott A (10³ cfu/cm²) and a single dose of A511 (3 × 10⁸ pfu/cm²) on camembert-type cheese, viable counts dropped 2.5 logs at the end of the 21 day ripening period. Repeated phage application did not further inhibit the bacteria, whereas a single higher dose (1 × 10⁹ pfu/cm²) was found to be more effective. On red-smear cheese ripened for 22 days, Listeria counts were down by more than 3 logs. Repeated application of A511 further delayed re-growth of Listeria, but did not affect bacterial counts after 22 days. With lower initial Listeria contamination (10¹ - 10² cfu/cm²), viable counts dropped below the limit of detection, corresponding to more than 6 logs reduction compared to the control. Our data clearly demonstrate the potential of bacteriophage for biocontrol of L. monocytogenes in soft cheese.

Open Access Article

Luminescence based enzyme-labeled phage (Phazyme) assays for rapid detection of Shiga toxin producing Escherichia coli serogroups

John D. Willford, Bledar Bisha, Kyle E. Bolenbaugh and Lawrence D. Goodridge
Pages 101 - 110
http://dx.doi.org/10.4161/bact.1.2.15666
Abstract | PDF

Most diagnostic approaches for Shiga toxin producing Escherichia coli (STEC) have been designed to detect only serogroup O157 that causes a majority, but not all STEC related outbreaks in the United States. Therefore, there is a need to develop methodology that would enable the detection of other STEC serogroups that cause disease. Three bacteriophages (phages) that infect STEC serogroups O26, O103, O111, O145 and O157 were chemically labeled with horseradish peroxidase (HRP). The enzyme-labeled phages (Phazymes) were individually combined with a sampling device (a swab), STEC serogroup-specific immunomagnetic separation (IMS) beads, bacterial enrichment broth and luminescent HRP substrate, in a self-contained test device, while luminescence was measured in a hand-held luminometer.

The O26 and O157 Phazyme assays correctly identified more than 93% of the bacteria tested during this study, the O123 Phazyme assay identified 89.6%, while the O111 and O145 Phazyme assays correctly detected 82.4% and 75.9%, respectively. The decreased specificity of the O111 and O145 assays was related to the broad host ranges of the phages used in both assays. The Phazyme assays were capable of directly detecting between 10⁵ and 10⁶ CFU/ml in pure culture, depending on the serogroup. In food trials, the O157 Phazyme assay was able to detect E. coli O157:H7 in spinach consistently at levels of 1 CFU/g and occasionally at levels of 0.1 CFU/g. The assay detected 100 CFU/100 cm² on swabbed meat samples and 10² CFU/100 ml in water samples. The Phazyme assay effectively detects most STEC in a simple and rapid manner, with minimal need for instrumentation to interpret the test result.




VIEWS AND COMMENTARIES

Open Access Article

Pros and cons of phage therapy

Catherine Loc-Carrillo and Stephen T. Abedon
Pages 111 - 114
http://dx.doi.org/10.4161/bact.1.2.14590
Abstract | PDF

Many publications list advantages and disadvantages associated with phage therapy, which is the use of bacterial viruses to combat populations of nuisance or pathogenic bacteria. The goal of this commentary is to discuss many of those issues in a single location. In terms of “Pros”, for example, phages can be bactericidal, can increase in number over the course of treatment, tend to only minimally disrupt normal flora, are equally effective against antibiotic-sensitive and antibiotic-resistant bacteria, often are easily discovered, seem to be capable of disrupting bacterial biofilms, and can have low inherent toxicities. In addition to these assets, we consider aspects of phage therapy that can contribute to its safety, economics, or convenience, but in ways that are perhaps less essential to the phage potential to combat bacteria. For example, autonomous phage transfer between animals during veterinary application could provide convenience or economic advantages by decreasing the need for repeated phage application, but is not necessarily crucial to therapeutic success. We also consider possible disadvantages to phage use as antibacterial agents. These “Cons”, however, tend to be either relatively minor.