101
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Siringan P, Connerton PL, Cummings NJ, Connerton IF. Alternative bacteriophage life cycles: the carrier state of Campylobacter jejuni. Open Biol 2014; 4:130200. [PMID: 24671947 PMCID: PMC3971406 DOI: 10.1098/rsob.130200] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 02/28/2014] [Indexed: 01/23/2023] Open
Abstract
Members of the genus Campylobacter are frequently responsible for human enteric disease, often through consumption of contaminated poultry products. Bacteriophages are viruses that have the potential to control pathogenic bacteria, but understanding their complex life cycles is key to their successful exploitation. Treatment of Campylobacter jejuni biofilms with bacteriophages led to the discovery that phages had established a relationship with their hosts typical of the carrier state life cycle (CSLC), where bacteria and bacteriophages remain associated in equilibrium. Significant phenotypic changes include improved aerotolerance under nutrient-limited conditions that would confer an advantage to survive in extra-intestinal environments, but a lack in motility eliminated their ability to colonize chickens. Under these circumstances, phages can remain associated with a compatible host and continue to produce free virions to prospect for new hosts. Moreover, we demonstrate that CSLC host bacteria can act as expendable vehicles for the delivery of bacteriophages to new host bacteria within pre-colonized chickens. The CSLC represents an important phase in the ecology of Campylobacter bacteriophage.
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Affiliation(s)
| | | | | | - Ian F. Connerton
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
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102
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Colles FM, McCarthy ND, Bliss CM, Layton R, Maiden MCJ. The long-term dynamics of Campylobacter colonizing a free-range broiler breeder flock: an observational study. Environ Microbiol 2014; 17:938-46. [PMID: 25588789 PMCID: PMC4390391 DOI: 10.1111/1462-2920.12415] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/28/2013] [Accepted: 11/05/2013] [Indexed: 01/03/2023]
Abstract
A free-range broiler breeder flock was studied in order to determine the natural patterns of Campylobacter colonization over a period of 63 weeks. Campylobacter sequence types (STs) were not mutually exclusive and on average colonized only 17.7% of the birds tested at any time. Campylobacter STs typically reached a peak in prevalence upon initial detection in the flock before tailing off, although the ST and antigenic flaA short variable region in combination were stable over a number of months. There was evidence that, with a couple of exceptions, the ecology of C. jejuni and C. coli differed, with the latter forming a more stable population. Despite being free range, no newly colonizing STs were detected over a 6-week period in autumn and a 10-week period in winter, towards the end of the study. There was limited evidence that those STs identified among broiler chicken flocks on the same farm site were likely to colonize the breeder flock earlier (R(2) 0.16, P 0.01). These results suggest that there is natural control of Campylobacter dynamics within a flock which could potentially be exploited in designing new intervention strategies, and that the two different species should perhaps be considered separately.
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Affiliation(s)
- Frances M Colles
- The Department of Zoology, University of Oxford, South Parks Road, South Parks Road, Oxford, OX1 3PS, UK
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103
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Wong CL, Sieo CC, Tan WS, Abdullah N, Hair-Bejo M, Abu J, Ho YW. Evaluation of a lytic bacteriophage, Φ st1, for biocontrol of Salmonella enterica serovar Typhimurium in chickens. Int J Food Microbiol 2014; 172:92-101. [DOI: 10.1016/j.ijfoodmicro.2013.11.034] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 11/22/2013] [Accepted: 11/28/2013] [Indexed: 01/16/2023]
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104
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Chan BK, Abedon ST, Loc-Carrillo C. Phage cocktails and the future of phage therapy. Future Microbiol 2013; 8:769-83. [PMID: 23701332 DOI: 10.2217/fmb.13.47] [Citation(s) in RCA: 517] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Viruses of bacteria, known as bacteriophages or phages, were discovered nearly 100 years ago. Their potential as antibacterial agents was appreciated almost immediately, with the first 'phage therapy' trials predating Fleming's discovery of penicillin by approximately a decade. In this review, we consider phage therapy that can be used for treating bacterial infections in humans, domestic animals and even biocontrol in foods. Following an overview of the topic, we explore the common practice - both experimental and, in certain regions of the world, clinical - of mixing therapeutic phages into cocktails consisting of multiple virus types. We conclude with a discussion of the commercial and medical context of phage cocktails as therapeutic agents. In comparing off-the-shelf versus custom approaches, we consider the merits of a middle ground, which we deem 'modifiable'. Finally, we explore a regulatory framework for such an approach based on an influenza vaccine model.
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Affiliation(s)
- Benjamin K Chan
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
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105
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Kittler S, Fischer S, Abdulmawjood A, Glünder G, Klein G. Effect of bacteriophage application on Campylobacter jejuni loads in commercial broiler flocks. Appl Environ Microbiol 2013; 79:7525-33. [PMID: 24077703 PMCID: PMC3837725 DOI: 10.1128/aem.02703-13] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 09/20/2013] [Indexed: 02/07/2023] Open
Abstract
Campylobacteriosis is the most frequent food-borne human enteritis. The major source for infection with Campylobacter spp. is broiler meat. Risk assessments consider the reduction of Campylobacter in primary production to be most beneficial for human health. The aim of this study was to test the efficacy of a bacteriophage application under commercial conditions which had proved to be effective in previous noncommercial studies under controlled experimental conditions. A phage cocktail for Campylobacter reduction was tested on three commercial broiler farms each with a control and an experimental group. Colonization of Campylobacter was confirmed prior to phage application in fecal samples. Subsequently, a phage cocktail was applied via drinking water in the experimental group (log10 5.8 to 7.5 PFU/bird). One day after phage application, Campylobacter counts of one experimental group were reduced under the detection limit (<50 CFU/g, P=0.0140) in fecal samples. At slaughter, a significant reduction of >log10 3.2 CFU/g cecal content compared to the control was still detected (P=0.0011). No significant reduction was observed in the experimental groups of the other trials. However, a significant drop in cecal Campylobacter counts occurred in a phage-contaminated control. These results suggest that maximum reduction of Campylobacter at the slaughterhouse might be achieved by phage application 1 to 4 days prior to slaughter.
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Affiliation(s)
- Sophie Kittler
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Samuel Fischer
- Clinic for Poultry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Amir Abdulmawjood
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Gerhard Glünder
- Clinic for Poultry, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Günter Klein
- Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Hannover, Germany
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106
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Ahn J, Kim S, Jung LS, Biswas D. In vitro assessment of the susceptibility of planktonic and attached cells of foodborne pathogens to bacteriophage p22-mediated salmonella lysates. J Food Prot 2013; 76:2057-62. [PMID: 24290682 DOI: 10.4315/0362-028x.jfp-13-183] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study was designed to evaluate the lytic activity of bacteriophage P22 against Salmonella Typhimurium ATCC 19585 (Salmonella Typhimurium P22(-)) at various multiplicities of infections (MOIs), the susceptibility of preattached Salmonella cells against bacteriophage P22, and the effect of P22-mediated bacterial lysates (extracellular DNA) on the attachment ability of Listeria monocytogenes ATCC 7644 and enterohemorrhagic Escherichia coli ATCC 700927 to surfaces. The numbers of attached Salmonella Typhimurium P22(-) cells were effectively reduced to below the detection limit (1 log CFU/ml) at the fixed inoculum levels of 3 × 10(-) CFU/ml (MOI = 3.12) and 3 × 10(3) CFU/ml (MOI = 4.12) by bacteriophage P22. The attached Salmonella Typhimurium P22(-) cells remained more than 2 log CFU/ml, with increasing inoculum levels from 3 × 10(4) to 3 × 10(7) CFU/ml infected with 4 × 10(8) PFU/ml of P22. The number of preattached Salmonella Typhimurium P22(-) cells was noticeably reduced by 2.72 log in the presence of P22. The highest specific attachment ability values for Salmonella Typhimurium P22(-), Salmonella Typhimurium ATCC 23555 carrying P22 prophage (Salmonella Typhimurium P22(+)), L. monocytogenes, and enterohemorrhagic E. coli were 2.09, 1.06, 1.86, and 1.08, respectively, in the bacteriophage-mediated cell-free supernatants (CFS) containing high amounts of extracellular DNA. These results suggest that bacteriophages could potentially be used to effectively eliminate planktonic and preattached Salmonella Typhimurium P22(-) cells with increasing MOI. However, further research is needed to understand the role of bacteriophage-induced lysates in bacterial attachment, which can provide useful information for the therapeutic use of bacteriophage in the food system.
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Affiliation(s)
- Juhee Ahn
- Department of Medical Biomaterials Engineering, Kangwon National University, Chuncheon, Gangwon 200-701, Republic of Korea
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107
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Abstract
Interest in using bacteriophages to control the growth and spread of bacterial pathogens is being revived in the wake of widespread antibiotic resistance. However, little is known about the ecological effects that high concentrations of phages in the environment might have on natural microbial communities. We review the current evidence suggesting phage-mediated environmental perturbation, with a focus on agricultural examples, and describe the potential implications for human health and agriculture. Specifically, we examine the known and potential consequences of phage application in certain agricultural practices, discuss the risks of evolved bacterial resistance to phages, and question whether the future of phage therapy will emulate that of antibiotic treatment in terms of widespread resistance. Finally, we propose some basic precautions that could preclude such phenomena and highlight existing methods for tracking bacterial resistance to phage therapeutic agents.
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Affiliation(s)
- Sean Meaden
- College of Life and Environmental Sciences, University of ExeterPenryn, UK
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108
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Tsonos J, Vandenheuvel D, Briers Y, De Greve H, Hernalsteens JP, Lavigne R. Hurdles in bacteriophage therapy: deconstructing the parameters. Vet Microbiol 2013; 171:460-9. [PMID: 24315040 DOI: 10.1016/j.vetmic.2013.11.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 10/30/2013] [Accepted: 11/01/2013] [Indexed: 10/26/2022]
Abstract
Bacterial infections in animals impact our food production, leading to economic losses due to food rejection and the need for preventive and curative measures. Since the onset of the antibiotic era, the rise of antibiotic-resistant pathogens is causing scares in health care and food producing facilities worldwide. In the search of new therapeutics, re-evaluation of bacteriophage (phage) therapy, using naturally occurring bacterial viruses to tackle infections, is gaining interest. Many studies report about phage therapy success, showing the value and power of these natural viruses. Although phages carry some interesting traits and their basic biology is now well understood, this review argues that phage therapy has not revealed all of its secrets and many parameters remain understudied, making the outcome of phage therapy highly variable depending on the disease incidence. These difficulties include poorly understood mechanisms of phage penetration and distribution throughout the body, the variable expression and accessibility of phage receptors on the bacterial host in in vivo conditions and the unusual (non-linear) phage pharmacokinetics. These parameters are not easily measured in realistic in vivo settings, but are nevertheless important hurdles to overcome the high variability of phage therapy trials. This critical approach is in accordance with Goethe's statement; "Difficulties increase the nearer we get to the goal". However, since the importance of the goal itself also rises, both difficulties and goal justify the need for additional in depth research in this domain.
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Affiliation(s)
- Jessica Tsonos
- Viral Genetics Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Structural and Molecular Microbiology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Department Structural Biology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Dieter Vandenheuvel
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Yves Briers
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
| | - Henri De Greve
- Structural and Molecular Microbiology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Department Structural Biology, VIB, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
| | | | - Rob Lavigne
- Laboratory of Gene Technology, KU Leuven, Kasteelpark Arenberg 21, 3001 Leuven, Belgium.
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109
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Predicting in vivo efficacy of therapeutic bacteriophages used to treat pulmonary infections. Antimicrob Agents Chemother 2013; 57:5961-8. [PMID: 24041900 DOI: 10.1128/aac.01596-13] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The potential of bacteriophage therapy to treat infections caused by antibiotic-resistant bacteria has now been well established using various animal models. While numerous newly isolated bacteriophages have been claimed to be potential therapeutic candidates on the basis of in vitro observations, the parameters used to guide their choice among billions of available bacteriophages are still not clearly defined. We made use of a mouse lung infection model and a bioluminescent strain of Pseudomonas aeruginosa to compare the activities in vitro and in vivo of a set of nine different bacteriophages (PAK_P1, PAK_P2, PAK_P3, PAK_P4, PAK_P5, CHA_P1, LBL3, LUZ19, and PhiKZ). For seven bacteriophages, a good correlation was found between in vitro and in vivo activity. While the remaining two bacteriophages were active in vitro, they were not sufficiently active in vivo under similar conditions to rescue infected animals. Based on the bioluminescence recorded at 2 and 8 h postinfection, we also define for the first time a reliable index to predict treatment efficacy. Our results showed that the bacteriophages isolated directly on the targeted host were the most efficient in vivo, supporting a personalized approach favoring an optimal treatment.
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110
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Arachchi GJG, Cruz CD, Dias-Wanigasekera BM, McIntyre L, Billington C, Hudson A, Flint SH, Mutukumira AN. Host range and in vitro lysis of Listeria monocytogenes seafood isolates by bacteriophages. FOOD SCI TECHNOL INT 2013; 20:591-603. [DOI: 10.1177/1082013213497211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Listeria-infecting bacteriophages (listeriaphages) can be used to control Listeria monocytogenes in the food industry. However, the sensitivity of many of seafood-borne Listeria strains to phages has not been reported. This research investigated the host ranges of three listeriaphages (FWLLm1, FWLLm3 and FWLLm5) by the formation of lytic zones and plaques on host lawns and in vitro lysis kinetics of listeriaphage FWLLm3. The study also predicted the phage titres required to lyse host cells. The host ranges of the phages were determined using 50 L. monocytogenes strains, of which 48 were isolated from the seafood industry and two from clinical cases. Of the 50 strains, 36 were tested at 25 and 30 ℃ and the remainder (14) at 15 and 25 ℃. Based on the formation of either discrete plaques or lytic zones (host kill zones), the host ranges of FWLLm1, FWLLm3 and FWLLm5 were about 87%, 81% and 87%, respectively, at 25 ℃. Six L. monocytogenes strains from the seafood environment were insensitive to all three phages, while the other seafood strains (42) were phage-sensitive. The adsorption rate constant ( k value) of listeriaphage FWLLm3 was between 1.2 × 10−9 and 1.6 × 10−9 ml/min across four host strains in tryptic soy broth at 25 ℃. The cultures (at 3–4 log colony-forming unit (CFU/ml) were completely lysed (<1 log CFU/ml) when cultures were infected with FWLLm3 at > 8.7 log phage-forming units (PFU/ml) for 30 min. Re-growth of phage-infected cultures was not detected after 24 h. The effective empirical phage titre was similar to the calculated titre using a kinetic model. Results indicate the potential use of the three phages for controlling L. monocytogenes strains in seafood processing environments.
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Affiliation(s)
- Geevika J Ganegama Arachchi
- Institute of Food, Nutrition and Human Health, Massey University, Albany Campus, North Shore City, Auckland, New Zealand
| | - Cristina D Cruz
- The New Zealand Institute for Plant & Food Research (PFR) Limited, Mt Albert, Auckland, New Zealand
| | | | - Lynn McIntyre
- Department of Food Science and Agri-Food Supply Chain Management, Harper Adams University, Edgmond, Newport, Shropshire, United Kingdom
| | - Craig Billington
- Food Programme, Institute of Environmental Science and Research (ESR) Limited, Christchurch Science Centre (CSC), Ilam, Christchurch, New Zealand
| | - Andrew Hudson
- Food Programme, Institute of Environmental Science and Research (ESR) Limited, Christchurch Science Centre (CSC), Ilam, Christchurch, New Zealand
| | - Steve H Flint
- Institute of Food, Nutrition and Human Health, Massey University, Albany Campus, North Shore City, Auckland, New Zealand
| | - Anthony N Mutukumira
- Institute of Food, Nutrition and Human Health, Massey University, Albany Campus, North Shore City, Auckland, New Zealand
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111
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Bandara S, Malmersjö S, Meyer T. Regulators of calcium homeostasis identified by inference of kinetic model parameters from live single cells perturbed by siRNA. Sci Signal 2013; 6:ra56. [PMID: 23838183 DOI: 10.1126/scisignal.2003649] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Assigning molecular functions and revealing dynamic connections between large numbers of partially characterized proteins in regulatory networks are challenges in systems biology. We showed that functions of signaling proteins can be discovered with a differential equations model of the underlying signaling process to extract specific molecular parameter values from single-cell, time-course measurements. By analyzing the effects of 250 small interfering RNAs on Ca(2+) signals in single cells over time, we identified parameters that were specifically altered in the Ca(2+) regulatory system. Analysis of the screen confirmed known functions of the Ca(2+) sensors STIM1 (stromal interaction molecule 1) and calmodulin and of Ca(2+) channels and pumps localized in the endoplasmic reticulum (ER) or plasma membrane. Furthermore, we showed that the Alzheimer's disease-linked protein presenilin-2 and the channel protein ORAI2 prevented overload of ER Ca(2+) and that feedback from Ca(2+) to phosphatidylinositol 4-kinase and PLCδ (phospholipase Cδ) may regulate the abundance of the plasma membrane lipid PI(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) to control Ca(2+) extrusion. Thus, functions of signaling proteins and dynamic regulatory connections can be identified by extracting molecular parameter values from single-cell, time-course data.
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Affiliation(s)
- Samuel Bandara
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA.
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112
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Mendes JJ, Leandro C, Corte-Real S, Barbosa R, Cavaco-Silva P, Melo-Cristino J, Górski A, Garcia M. Wound healing potential of topical bacteriophage therapy on diabetic cutaneous wounds. Wound Repair Regen 2013; 21:595-603. [DOI: 10.1111/wrr.12056] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/18/2013] [Indexed: 12/17/2022]
Affiliation(s)
| | | | | | | | | | - José Melo-Cristino
- Faculty of Medicine of the University of Lisbon; Institute of Microbiology; Lisbon; Portugal
| | - Andrzej Górski
- Bacteriophage Laboratory; Ludwik Hirszfeld Institute of Immunology and Experimental Therapy; Polish Academy of Sciences; Wroclaw; Poland
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113
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Tomat D, Mercanti D, Balagué C, Quiberoni A. Phage biocontrol of enteropathogenic and Shiga toxin-producing Escherichia coli
during milk fermentation. Lett Appl Microbiol 2013; 57:3-10. [DOI: 10.1111/lam.12074] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 03/25/2013] [Accepted: 03/25/2013] [Indexed: 11/29/2022]
Affiliation(s)
- D. Tomat
- Área de Bacteriología; Facultad de Ciencias Bioquímicas y Farmacéuticas; Universidad Nacional de Rosario; Rosario Argentina
| | - D. Mercanti
- Facultad de Ingeniería Química; Instituto de Lactología Industrial (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas); Santa Fe Argentina
| | - C. Balagué
- Área de Bacteriología; Facultad de Ciencias Bioquímicas y Farmacéuticas; Universidad Nacional de Rosario; Rosario Argentina
| | - A. Quiberoni
- Facultad de Ingeniería Química; Instituto de Lactología Industrial (Universidad Nacional del Litoral - Consejo Nacional de Investigaciones Científicas y Técnicas); Santa Fe Argentina
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114
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Warning A, Datta AK. Interdisciplinary engineering approaches to study how pathogenic bacteria interact with fresh produce. J FOOD ENG 2013. [DOI: 10.1016/j.jfoodeng.2012.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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115
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116
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Cox CR, Rees JC, Voorhees KJ. Modeling bacteriophage amplification as a predictive tool for optimized MALDI-TOF MS-based bacterial detection. JOURNAL OF MASS SPECTROMETRY : JMS 2012; 47:1435-1441. [PMID: 23147819 DOI: 10.1002/jms.3087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a valuable tool for rapid bacterial detection and identification but is limited by the need for relatively high cell count samples, which have been grown under strictly controlled conditions. These requirements can be eliminated by the natural infection of a viable bacterial species of interest with a host-specific phage. This produces a rapid increase in phage protein concentrations in comparison to bacterial concentrations, which can in turn be exploited as a method for signal amplification during MALDI-TOF MS. One drawback to this approach is the requirement for repetitive, time-consuming sample preparation and analysis applied over the course of a phage infection to monitor phage concentrations as a function of time to determine the MALDI-TOF MS detection limit. To reduce the requirement for repeated preparation and analysis, a modified phage therapy model was investigated as a means for predicting the time during a given phage infection when a detectable signal would occur. The modified model used a series of three differential equations composed of predetermined experimental parameters including phage burst size and burst time to predict progeny phage concentrations as a function of time. Using Yersinia pestis with plague diagnostic phage φA1122 and Escherichia coli with phage MS2 as two separate, well-characterized model phage-host pairs, we conducted in silico modeling of the infection process and compared it with experimental infections monitored in real time by MALDI-TOF MS. Significant agreement between mathematically calculated phage growth curves and those experimentally obtained by MALDI-TOF MS was observed, thus verifying this method's utility for significant time and labor reduction.
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Affiliation(s)
- Christopher R Cox
- Colorado School of Mines, Department of Chemistry and Geochemistry, Golden, CO 80401, USA
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117
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Bardina X, Bascompte D, Rovira C, Tindel S. An analysis of a stochastic model for bacteriophage systems. Math Biosci 2012; 241:99-108. [PMID: 23089558 DOI: 10.1016/j.mbs.2012.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 09/28/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
In this article, we analyze a system modeling bacteriophage treatments for infections in a noisy context. In the small noise regime, we show that after a reasonable amount of time the system is close to a bacteria free equilibrium (which is a relevant biologic information) with high probability. Mathematically speaking, our study hinges on concentration techniques for delayed stochastic differential equations.
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Affiliation(s)
- X Bardina
- Departament de Matemàtiques, Facultat de Ciències, Edifici C, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
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118
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Affiliation(s)
- Eric C Keen
- Department of Natural Sciences, Montgomery College Germantown, MD, USA
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119
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Luo Z, Simmons CW, VanderGheynst JS, Nitin N. Quantitative real time measurements of bacteria–bacteriophages interactions in fresh lettuce leaves. J FOOD ENG 2012. [DOI: 10.1016/j.jfoodeng.2011.12.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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120
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Phage inactivation of Staphylococcus aureus in fresh and hard-type cheeses. Int J Food Microbiol 2012; 158:23-7. [PMID: 22795798 DOI: 10.1016/j.ijfoodmicro.2012.06.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 06/15/2012] [Accepted: 06/21/2012] [Indexed: 11/23/2022]
Abstract
Bacteriophages are regarded as natural antibacterial agents in food since they are able to specifically infect and lyse food-borne pathogenic bacteria without disturbing the indigenous microbiota. Two Staphylococcus aureus obligately lytic bacteriophages (vB_SauS-phi-IPLA35 and vB_SauS-phi-SauS-IPLA88), previously isolated from the dairy environment, were evaluated for their potential as biocontrol agents against this pathogenic microorganism in both fresh and hard-type cheeses. Pasteurized milk was contaminated with S. aureus Sa9 (about 10(6) CFU/mL) and a cocktail of the two lytic phages (about 10(6) PFU/mL) was also added. For control purposes, cheeses were manufactured without addition of phages. In both types of cheeses, the presence of phages resulted in a notorious decrease of S. aureus viable counts during curdling. In test fresh cheeses, a reduction of 3.83 log CFU/g of S. aureus occurred in 3h compared with control cheese, and viable counts were under the detection limits after 6h. The staphylococcal strain was undetected in both test and control cheeses at the end of the curdling process (24 h) and, of note, no re-growth occurred during cold storage. In hard cheeses, the presence of phages resulted in a continuous reduction of staphylococcal counts. In curd, viable counts of S. aureus were reduced by 4.64 log CFU/g compared with the control cheeses. At the end of ripening, 1.24 log CFU/g of the staphylococcal strain was still detected in test cheeses whereas 6.73log CFU/g was present in control cheeses. Starter strains were not affected by the presence of phages in the cheese making processes and cheeses maintained their expected physico-chemical properties.
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121
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Tabla R, Martínez B, Rebollo J, González J, Ramírez M, Roa I, Rodríguez A, García P. Bacteriophage performance against Staphylococcus aureus in milk is improved by high hydrostatic pressure treatments. Int J Food Microbiol 2012; 156:209-13. [DOI: 10.1016/j.ijfoodmicro.2012.03.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/19/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
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122
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A method for generation phage cocktail with great therapeutic potential. PLoS One 2012; 7:e31698. [PMID: 22396736 PMCID: PMC3291564 DOI: 10.1371/journal.pone.0031698] [Citation(s) in RCA: 171] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 01/16/2012] [Indexed: 01/21/2023] Open
Abstract
Background Bacteriophage could be an alternative to conventional antibiotic therapy against multidrug-resistant bacteria. However, the emergence of resistant variants after phage treatment limited its therapeutic application. Methodology/Principal Findings In this study, an approach, named “Step-by-Step” (SBS), has been established. This method takes advantage of the occurrence of phage-resistant bacteria variants and ensures that phages lytic for wild-type strain and its phage-resistant variants are selected. A phage cocktail lytic for Klebsiella pneumoniae was established by the SBS method. This phage cocktail consisted of three phages (GH-K1, GH-K2 and GH-K3) which have different but overlapping host strains. Several phage-resistant variants of Klebsiella pneumoniae were isolated after different phages treatments. The virulence of these variants was much weaker [minimal lethal doses (MLD)>1.3×109 cfu/mouse] than that of wild-type K7 countpart (MLD = 2.5×103 cfu/mouse). Compared with any single phage, the phage cocktail significantly reduced the mutation frequency of Klebsiella pneumoniae and effectively rescued Klebsiella pneumoniae bacteremia in a murine K7 strain challenge model. The minimal protective dose (MPD) of the phage cocktail which was sufficient to protect bacteremic mice from lethal K7 infection was only 3.0×104 pfu, significantly smaller (p<0.01) than that of single monophage. Moreover, a delayed administration of this phage cocktail was still effective in protection against K7 challenge. Conclusions/Significance Our data showed that the phage cocktail was more effective in reducing bacterial mutation frequency and in the rescue of murine bacteremia than monophage suggesting that phage cocktail established by SBS method has great therapeutic potential for multidrug-resistant bacteria infection.
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123
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Escobar-Páramo P, Gougat-Barbera C, Hochberg ME. Evolutionary dynamics of separate and combined exposure of Pseudomonas fluorescens SBW25 to antibiotics and bacteriophage. Evol Appl 2012; 5:583-92. [PMID: 23028399 PMCID: PMC3461141 DOI: 10.1111/j.1752-4571.2012.00248.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 01/09/2012] [Indexed: 01/21/2023] Open
Abstract
The use of bacteriophages against pathogenic bacteria in health care and in the food industry is now being advocated as an alternative to the use of antibiotics. But what is the evolutionary response for a bacterial population if both antibiotics and phages are used in combination? We employ an experimental evolution approach to address these questions and exposed Pseudomonas fluorescens SBW25 and a related hypermutator strain (mutS−) to the action of the antibiotic rifampicin and the lytic bacteriophage SBW25ϕ2. We then compared the densities, growth rates, and the mutations at the rpoB locus leading to rifampicin resistance of the evolved bacterial populations. We observed that the evolutionary response of populations under different treatments varied depending on the order in which the antimicrobials were added and whether the bacterium was a hypermutator. We found that wild-type rifampicin-resistant populations involved in biofilm formation often reverted to rifampicin sensitivity when stresses were added sequentially. In contrast, when the mortality agents were added simultaneously, phage populations frequently went extinct and the bacteria evolved antibiotic resistance. However, populations of the hypermutator mutS− converged to a single genotype at the rpoB locus. Future investigation on other bacteria and using different antibiotics and bacteriophage are needed to evaluate the generality of our findings.
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Affiliation(s)
- Patricia Escobar-Páramo
- Institut des Sciences de l'Evolution, UMR5554, Université Montpellier II Montpellier, France
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124
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Hooton SP, Atterbury RJ, Connerton IF. Application of a bacteriophage cocktail to reduce Salmonella Typhimurium U288 contamination on pig skin. Int J Food Microbiol 2011; 151:157-63. [DOI: 10.1016/j.ijfoodmicro.2011.08.015] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 08/15/2011] [Accepted: 08/16/2011] [Indexed: 01/21/2023]
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125
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Siringan P, Connerton PL, Payne RJH, Connerton IF. Bacteriophage-Mediated Dispersal of Campylobacter jejuni Biofilms. Appl Environ Microbiol 2011; 77:3320-6. [PMID: 21441325 PMCID: PMC3126433 DOI: 10.1128/aem.02704-10] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 03/17/2011] [Indexed: 11/20/2022] Open
Abstract
Bacteria in their natural environments frequently exist as mixed surface-associated communities, protected by extracellular material, termed biofilms. Biofilms formed by the human pathogen Campylobacter jejuni may arise in the gastrointestinal tract of animals but also in water pipes and other industrial situations, leading to their possible transmission into the human food chain either directly or via farm animals. Bacteriophages are natural predators of bacteria that usually kill their prey by cell lysis and have potential application for the biocontrol and dispersal of target bacteria in biofilms. The effects of virulent Campylobacter specific-bacteriophages CP8 and CP30 on C. jejuni biofilms formed on glass by strains NCTC 11168 and PT14 at 37°C under microaerobic conditions were investigated. Independent bacteriophage treatments (n ≥ 3) led to 1 to 3 log₁₀ CFU/cm² reductions in the viable count 24 h postinfection compared with control levels. In contrast, bacteriophages applied under these conditions effected a reduction of less than 1 log₁₀ CFU/ml in planktonic cells. Resistance to bacteriophage in bacteria surviving bacteriophage treatment of C. jejuni NCTC 11168 biofilms was 84% and 90% for CP8 and CP30, respectively, whereas bacteriophage resistance was not found in similarly recovered C. jejuni PT14 cells. Dispersal of the biofilm matrix by bacteriophage was demonstrated by crystal violet staining and transmission electron microscopy. Bacteriophage may play an important role in the control of attachment and biofilm formation by Campylobacter in situations where biofilms occur in nature, and they have the potential for application in industrial situations leading to improvements in food safety.
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Affiliation(s)
- Patcharin Siringan
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Phillippa L. Connerton
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Robert J. H. Payne
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom
| | - Ian F. Connerton
- Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom
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126
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Pouillot F, Blois H, Iris F. Genetically engineered virulent phage banks in the detection and control of emergent pathogenic bacteria. Biosecur Bioterror 2010; 8:155-69. [PMID: 20569057 DOI: 10.1089/bsp.2009.0057] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Natural outbreaks of multidrug-resistant microorganisms can cause widespread devastation, and several can be used or engineered as agents of bioterrorism. From a biosecurity standpoint, the capacity to detect and then efficiently control, within hours, the spread and the potential pathological effects of an emergent outbreak, for which there may be no effective antibiotics or vaccines, become key challenges that must be met. We turned to phage engineering as a potentially highly flexible and effective means to both detect and eradicate threats originating from emergent (uncharacterized) bacterial strains. To this end, we developed technologies allowing us to (1) concurrently modify multiple regions within the coding sequence of a gene while conserving intact the remainder of the gene, (2) reversibly interrupt the lytic cycle of an obligate virulent phage (T4) within its host, (3) carry out efficient insertion, by homologous recombination, of any number of engineered genes into the deactivated genomes of a T4 wild-type phage population, and (4) reactivate the lytic cycle, leading to the production of engineered infective virulent recombinant progeny. This allows the production of very large, genetically engineered lytic phage banks containing, in an E. coli host, a very wide spectrum of variants for any chosen phage-associated function, including phage host-range. Screening of such a bank should allow the rapid isolation of recombinant T4 particles capable of detecting (ie, diagnosing), infecting, and destroying hosts belonging to gram-negative bacterial species far removed from the original E. coli host.
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127
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Bacteriophage ecology in Escherichia coli and Pseudomonas aeruginosa mixed-biofilm communities. Appl Environ Microbiol 2010; 77:821-9. [PMID: 21131510 DOI: 10.1128/aem.01797-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Phage therapy is being reexamined as a strategy for bacterial control in medical and other environments. As microorganisms often live in mixed populations, we examined the effect of Escherichia coli bacteriophage λW60 and Pseudomonas aeruginosa bacteriophage PB-1 infection on the viability of monoculture and mixed-species biofilm and planktonic cultures. In mixed-species biofilm communities, E. coli and P. aeruginosa maintained stable cell populations in the presence of one or both phages. In contrast, E. coli planktonic populations were severely depleted in coculture in the presence of λW60. Both E. coli and P. aeruginosa developed phage resistance in planktonic culture; however, reduced resistance was observed in biofilm communities. Increased phage titers and reduced resistance in biofilms suggest that phage can replicate on susceptible cells in biofilms. Infectious phage could be released from mixed-culture biofilms upon treatment with Tween 20 but not upon treatment with chloroform. Tween 20 and chloroform treatments had no effect on phage associated with planktonic cells, suggesting that planktonic phage were not cell or matrix associated. Transmission electron microscopy showed bacteriophage particles to be enmeshed in the extracellular polymeric substance component of biofilms and that this substance could be removed by Tween 20 treatment. Overall, this study demonstrates how mixed-culture biofilms can maintain a reservoir of viable phage and bacterial populations in the environment.
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128
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Mahony J, McAuliffe O, Ross RP, van Sinderen D. Bacteriophages as biocontrol agents of food pathogens. Curr Opin Biotechnol 2010; 22:157-63. [PMID: 21115341 DOI: 10.1016/j.copbio.2010.10.008] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 10/04/2010] [Accepted: 10/11/2010] [Indexed: 11/18/2022]
Abstract
Bacteriophages have long been recognized for their potential as biotherapeutic agents. The recent approval for the use of phages of Listeria monocytogenes for food safety purposes has increased the impetus of phage research to uncover phage-mediated applications with activity against other food pathogens. Areas of emerging and growing significance, such as predictive modelling and genomics, have shown their potential and impact on the development of new technologies to combat food pathogens. This review will highlight recent advances in the research of phages that target food pathogens and that promote their use in biosanitation, while it will also discuss its limitations.
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Affiliation(s)
- Jennifer Mahony
- Department of Microbiology, University College Cork, Cork, Ireland
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129
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Carvalho CM, Gannon BW, Halfhide DE, Santos SB, Hayes CM, Roe JM, Azeredo J. The in vivo efficacy of two administration routes of a phage cocktail to reduce numbers of Campylobacter coli and Campylobacter jejuni in chickens. BMC Microbiol 2010; 10:232. [PMID: 20809975 PMCID: PMC2940857 DOI: 10.1186/1471-2180-10-232] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 09/01/2010] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Poultry meat is one of the most important sources of human campylobacteriosis, an acute bacterial enteritis which is a major problem worldwide. Campylobacter coli and Campylobacter jejuni are the most common Campylobacter species associated with this disease. These pathogens live in the intestinal tract of most avian species and under commercial conditions they spread rapidly to infect a high proportion of the flock, which makes their treatment and prevention very difficult. Bacteriophages (phages) are naturally occurring predators of bacteria with high specificity and also the capacity to evolve to overcome bacterial resistance. Therefore phage therapy is a promising alternative to antibiotics in animal production. This study tested the efficacy of a phage cocktail composed of three phages for the control of poultry infected with C. coli and C. jejuni. Moreover, it evaluated the effectiveness of two routes of phage administration (by oral gavage and in feed) in order to provide additional information regarding their future use in a poultry unit. RESULTS The results indicate that experimental colonisation of chicks was successful and that the birds showed no signs of disease even at the highest dose of Campylobacter administered. The phage cocktail was able to reduce the titre of both C. coli and C. jejuni in faeces by approximately 2 log10 cfu/g when administered by oral gavage and in feed. This reduction persisted throughout the experimental period and neither pathogen regained their former numbers. The reduction in Campylobacter titre was achieved earlier (2 days post-phage administration) when the phage cocktail was incorporated in the birds' feed. Campylobacter strains resistant to phage infection were recovered from phage-treated chickens at a frequency of 13%. These resistant phenotypes did not exhibit a reduced ability to colonize the chicken guts and did not revert to sensitive types. CONCLUSIONS Our findings provide further evidence of the efficacy of phage therapy for the control of Campylobacter in poultry. The broad host range of the novel phage cocktail enabled it to target both C. jejuni and C. coli strains. Moreover the reduction of Campylobacter by approximately 2 log10cfu/g, as occurred in our study, could lead to a 30-fold reduction in the incidence of campylobacteriosis associated with consumption of chicken meals (according to mathematical models). To our knowledge this is the first report of phage being administered in feed to Campylobacter-infected chicks and our results show that it lead to an earlier and more sustainable reduction of Campylobacter than administration by oral gavage. Therefore the present study is of extreme importance as it has shown that administering phages to poultry via the food could be successful on a commercial scale.
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Affiliation(s)
- Carla M Carvalho
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Ben W Gannon
- University of Bristol, Department of Clinical Veterinary Science, Langford, North Somerset, BS40 5DU, UK
| | - Deborah E Halfhide
- University of Bristol, Department of Clinical Veterinary Science, Langford, North Somerset, BS40 5DU, UK
| | - Silvio B Santos
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Christine M Hayes
- University of Bristol, Department of Clinical Veterinary Science, Langford, North Somerset, BS40 5DU, UK
| | - John M Roe
- University of Bristol, Department of Clinical Veterinary Science, Langford, North Somerset, BS40 5DU, UK
| | - Joana Azeredo
- IBB - Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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130
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Letkiewicz S, Międzybrodzki R, Kłak M, Jończyk E, Weber-Dąbrowska B, Górski A. The perspectives of the application of phage therapy in chronic bacterial prostatitis. ACTA ACUST UNITED AC 2010; 60:99-112. [DOI: 10.1111/j.1574-695x.2010.00723.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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131
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Use of logistic regression for prediction of the fate of Staphylococcus aureus in pasteurized milk in the presence of two lytic phages. Appl Environ Microbiol 2010; 76:6038-46. [PMID: 20656872 DOI: 10.1128/aem.00613-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The use of bacteriophages provides an attractive approach to the fight against food-borne pathogenic bacteria, since they can be found in different environments and are unable to infect humans, both characteristics of which support their use as biocontrol agents. Two lytic bacteriophages, vB_SauS-phiIPLA35 (phiIPLA35) and vB_SauS-phiIPLA88 (phiIPLA88), previously isolated from the dairy environment inhibited the growth of Staphylococcus aureus. To facilitate the successful application of both bacteriophages as biocontrol agents, probabilistic models for predicting S. aureus inactivation by the phages in pasteurized milk were developed. A linear logistic regression procedure was used to describe the survival/death interface of S. aureus after 8 h of storage as a function of the initial phage titer (2 to 8 log(10) PFU/ml), initial bacterial contamination (2 to 6 log(10) CFU/ml), and temperature (15 to 37 degrees C). Two successive models were built, with the first including only data from the experimental design and a global one in which results derived from the validation experiments were also included. The temperature, interaction temperature-initial level of bacterial contamination, and initial level of bacterial contamination-phage titer contributed significantly to the first model prediction. However, only the phage titer and temperature were significantly involved in the global model prediction. The predictions of both models were fail-safe and highly consistent with the observed S. aureus responses. Nevertheless, the global model, deduced from a higher number of experiments (with a higher degree of freedom), was dependent on a lower number of variables and had an apparent better fit. Therefore, it can be considered a convenient evolution of the first model. Besides, the global model provides the minimum phage concentration (about 2 x 10(8) PFU/ml) required to inactivate S. aureus in milk at different temperatures, irrespective of the bacterial contamination level.
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132
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García P, Martínez B, Rodríguez L, Rodríguez A. Synergy between the phage endolysin LysH5 and nisin to kill Staphylococcus aureus in pasteurized milk. Int J Food Microbiol 2010; 141:151-5. [DOI: 10.1016/j.ijfoodmicro.2010.04.029] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 04/28/2010] [Accepted: 04/30/2010] [Indexed: 11/26/2022]
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133
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Isolation and characterization of bacteriophages infecting Staphylococcus epidermidis. Curr Microbiol 2010; 61:601-8. [PMID: 20449591 DOI: 10.1007/s00284-010-9659-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
Abstract
Bacteriophages infecting Staphylococcus epidermidis were isolated by mitomycin C induction. Three distinct phages (vB_SepiS-phiIPLA5, vB_SepiS-phiIPLA6, and vB_SepiS-phiIPLA7)-defined by plaque morphology, structure, virion proteins pattern, DNA restriction bands, and host range-were obtained. One-step growth curves of bacteriophages under optimal growth conditions for S. epidermidis F12 revealed eclipse and latent periods of 5-10 and 10-15 min, respectively, with burst sizes of about 5 to 30 PFU per infected cell. Transmission electron microscopy revealed that the phages were of similar size and belonged to the Siphoviridae family. Phage phi-IPLA7 had the broadest host range infecting 21 out of 65 S. epidermidis isolates. Phage phi-IPLA5 seemed to be a virulent phage probably derived from phi-IPLA6. Phages phi-IPLA5 and phi-IPLA7 exhibited increasing plaques surrounded by a halo that could be indicative of a polysaccharide depolymerase activity. Viable counts, determined during the infection of S. epidermidis F12, confirmed that phi-IPLA5 had a potent lytic capability and reduced S. epidermidis population by 5.67 log units in 8 h of incubation; in the presence of the mixture of phi-IPLA6 and phi-IPLA7, however, a reduction of 2.27 log units was detected.
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134
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YE JIANXIONG, KOSTRZYNSKA MAGDALAENA, DUNFIELD KARI, WARRINER KEITH. Control of Salmonella on Sprouting Mung Bean and Alfalfa Seeds by Using a Biocontrol Preparation Based on Antagonistic Bacteria and Lytic Bacteriophages. J Food Prot 2010; 73:9-17. [DOI: 10.4315/0362-028x-73.1.9] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The following reports on the application of a combination of antagonistic bacteria and lytic bacteriophages to control the growth of Salmonella on sprouting mung beans and alfalfa seeds. Antagonistic bacteria were isolated from mung bean sprouts and tomatoes by using the deferred plate assay to assess anti-Salmonella activity. From the isolates screened, an Enterobacter asburiae strain (labeled “JX1”) exhibited stable antagonistic activity against a broad range of Salmonella serovars (Agona, Berta, Enteritidis, Hadar, Heidelberg, Javiana, Montevideo, Muenchen, Newport, Saint Paul, and Typhimurium). Lytic bacteriophages against Salmonella were isolated from pig or cattle manure effluent. A bacteriophage cocktail prepared from six isolates was coinoculated with E. asburiae JX1 along with Salmonella in broth culture. The combination of E. asburiae JX1 and bacteriophage cocktail reduced the levels of Salmonella by 5.7 to 6.4 log CFU/ml. Mung beans inoculated with Salmonella and sprouted over a 4-day period attained levels of 6.72 ± 0.78 log CFU/g. In contrast, levels of Salmonella were reduced to 3.31 ± 2.48 or 1.16 ± 2.14 log CFU/g when the pathogen was coinoculated with bacteriophages or E. asburiae JX1, respectively. However, by using a combination of E. asburiae JX1and bacteriophages, the levels of Salmonella associated with mung bean sprouts were only detected by enrichment. The biocontrol preparation was effective at controlling the growth of Salmonella under a range of sprouting temperatures (20 to 30°C) and was equally effective at suppressing the growth of Salmonella on sprouting alfalfa seeds. The combination of E. asburiae JX1 and bacteriophages represents a promising, chemical-free approach for controlling the growth of Salmonella on sprouting seeds.
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Affiliation(s)
- JIANXIONG YE
- 1Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - MAGDALAENA KOSTRZYNSKA
- 2Food Program, Agriculture & Agri-Food Canada, 93 Stone Road West, Guelph, Ontario, Canada N1G 5C9
| | - KARI DUNFIELD
- 3Land Resource Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - KEITH WARRINER
- 1Department of Food Science, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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135
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García P, Madera C, Martínez B, Rodríguez A, Evaristo Suárez J. Prevalence of bacteriophages infecting Staphylococcus aureus in dairy samples and their potential as biocontrol agents. J Dairy Sci 2009; 92:3019-26. [DOI: 10.3168/jds.2008-1744] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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136
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Abstract
We use kinetic models to investigate how to design antimicrobial phage therapies to minimize emergence of resistant bacteria. We do this by modifying the "mutant selection window" hypothesis in a way that accounts for the ongoing self-replication of the phage. We show that components of combination phage therapies need to be appropriately matched if treatment is to avoid the emergence of resistant bacteria. Matching of components is more easily achieved when phage dosages are high enough that ongoing phage replication is not needed for the clearance of the bacteria. Theoretical predictions such as ours need to be tested experimentally if applications of phage therapy are to avoid the problems of widespread resistance that have beset chemical antibiotics.
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