Dataset Information

On-Demand Isolation of Bacteriophages Against Drug-Resistant Bacteria for Personalized Phage Therapy.

ABSTRACT: Bacteriophages are bacterial viruses, capable of killing even multi-drug resistant bacterial cells. For this reason, therapeutic use of phages is considered as a possible alternative to conventional antibiotics. However, phages are very host specific in comparison to wide-spectrum antibiotics and thus preparation of phage-cocktails beforehand against pathogens can be difficult. In this study, we evaluate whether it may be possible to isolate phages on-demand from environmental reservoir. We attempted to enrich infectious bacteriophages from sewage against nosocomial drug-resistant bacterial strains of different medically important species in order to evaluate the probability of discovering novel therapeutic phages. Stability and host-range were determined for the acquired phages. Our results suggest that on-demand isolation of phages is possible against Pseudomonas aeruginosa, Salmonella and extended spectrum beta-lactamase Escherichia coli and Klebsiella pneumoniae. The probability of finding suitable phages was less than 40% against vancomycin resistant Enterococcus and Acinetobacter baumannii strains. Furthermore, isolation of new phages against methicillin resistant Staphylococcus aureus strains was found to be very difficult.

SUBMITTER: Mattila S

PROVIDER: S-EPMC4643220 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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On-Demand Isolation of Bacteriophages Against Drug-Resistant Bacteria for Personalized Phage Therapy.

Mattila Sari S Ruotsalainen Pilvi P Jalasvuori Matti M

Frontiers in microbiology 20151113

Bacteriophages are bacterial viruses, capable of killing even multi-drug resistant bacterial cells. For this reason, therapeutic use of phages is considered as a possible alternative to conventional antibiotics. However, phages are very host specific in comparison to wide-spectrum antibiotics and thus preparation of phage-cocktails beforehand against pathogens can be difficult. In this study, we evaluate whether it may be possible to isolate phages on-demand from environmental reservoir. We atte ...[more]

PMID: 26617601

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Project description:Antimicrobial resistance (AMR) is a major problem globally. The main bacterial organisms associated with urinary tract infection (UTI) associated sepsis are E. coli and Klebsiella along with Enterobacter species. These all have AMR strains known as ESBL (Extended Spectrum Beta-Lactamase), which are featured on the WHO priority pathogens list as "critical" for research. Bacteriophages (phages), as viruses that can infect and kill bacteria, could provide an effective tool to tackle these AMR strains. There is currently no "gold standard" for developing a phage cocktail. Here we describe a novel approach to develop an effective phage cocktail against a set of ESBL-producing E. coli and Klebsiella largely isolated from patients in United Kingdom hospitals. By comparing different measures of phage efficacy, we show which are the most robust, and suggest an efficient screening cascade that could be used to develop phage cocktails to target other AMR bacterial species. A target panel of 38 ESBL-producing clinical strains isolated from urine samples was collated and used to test phage efficacy. After an initial screening of 68 phages, six were identified and tested against these 38 strains to determine their clinical coverage and killing efficiency. To achieve this, we assessed four different methods to assess phage virulence across these bacterial isolates. These were the Direct Spot Test (DST), the Efficiency of Plating (EOP) assay, the planktonic killing assay (PKA) and the biofilm assay. The final ESBL cocktail of six phages could effectively kill 23/38 strains (61%), for Klebsiella 13/19 (68%) and for E. coli 10/19 (53%) based on the PKA data. The ESBL E. coli collection had six isolates from the prevalent UTI-associated ST131 sequence type, five of which were targeted effectively by the final cocktail. Of the four methods used to assess phage virulence, the data suggests that PKAs are as effective as the much more time-consuming EOPs and data for the two assays correlates well. This suggests that planktonic killing is a good proxy to determine which phages should be used in a cocktail. This assay when combined with the virulence index also allows "phage synergy" to inform cocktail design.

Project description:BackgroundPhage therapy or use of lytic bacteriophages for eliminating bacterial populations has been developed for several aspects of human affairs such as medicine, agriculture and food industries.ObjectivesThe high load of coliforms of treated wastewater effluents that are discharged into the rivers or agricultural lands is a serious concern of the Iran Department of Environment and the reduction of coliforms using phages to overcome this problem is an asset. This research aimed to isolate and identify specific lytic coliphages and investigate their effects on native and standard Escherichia coli strains as well as coliform populations in municipal wastewater.Materials and methodsThe wastewater sample was cultured on selective culture media to isolate a native coliform strain and characterized using molecular methods. River water was centrifuged and passed through a 0.45 μm filter and its lytic coliphages were enriched and purified against a native E. coli as well as a standard E. coli strain. Municipal wastewater was treated with isolated lytic coliphages and most probable number (MPN) reduction was examined.ResultsE. coli SBSWF27, which is a native strain of E. coli from Isfahan municipal wastewater treatment plant, was isolated and characterized. Also two novel bacteriophages related to Myoviridae and Podoviridae families of bacteriophages from Zayandehrood River (Isfahan, Iran) were isolated. These coliphages had lytic effects on E. coli PTCC1399 and E. coli SBSWF27 as coliform's index. The myovirus had a hexagonal head measuring 27.28 nm and a noncontractile tail measuring 204.5 × 13.63 nm. The podovirus had an oval head measuring 98 × 35 nm and a tail, 14 nm in diameter. The treatment of municipal sewage with the coliphage mixture resulted in a 22-fold decrease of the coliform's MPN from 2400 to 110 after two hours of incubation.ConclusionsThis is the first report on isolation and identification of two novel lytic myovirus and podovirus from Zayandehrood River in Isfahan that had lytic effects on E. coli PTCC1399 and E. coli SBSWF27 strains as well as coliform's population of Isfahan municipal wastewater. We suggest that the use of these lytic coliphages for reduction of coliform's population in sewage could be considered as an effective and simple alternative for costly replacement of instruments and establishments of the old wastewater treatment plants.

Dataset Information

On-Demand Isolation of Bacteriophages Against Drug-Resistant Bacteria for Personalized Phage Therapy.

Publications

On-Demand Isolation of Bacteriophages Against Drug-Resistant Bacteria for Personalized Phage Therapy.

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