Isolation and characterisation of phages infecting Legionella
Introduction:
Legionella is the causative agent of Legionnaires’ disease, a potentially fatal acute pneumonia with record high morbidity and mortality rates. Legionella has been shown to be resistant to antibiotics and its detection is difficult, leading to misdiagnosis, making treatment of this infection challenging. Clearly, there is a great need to identify novel and more effective therapeutic agents for this disease and more specific diagnostic tools for this pathogen. Bacteriophages (phages) are a potential tool to be exploited for this purpose. Here, we isolated and characterised lytic and temperate phages for further development as therapeutic agents and diagnostic tools Legionella spp.
Method:
A total of 180 water and sediment samples were collected from natural reservoirs and man-made systems, such as cooling towers, etc. The samples were first analysed for the presence of free phages using host range analysis, followed by Transmission Electron Microscopy (TEM). Subsequently, the same water samples were heat-treated and enriched for Legionella isolation. Bacteria isolated from the water samples were analysed using PCR targeting the macrophage infectivity potentiator (mip) gene, with resulting products sequenced to confirm the identity of the isolates.
Results and discussion:
After phage enrichment, 10 out of 180 water and sediment samples produced confluent zones of lysis on lawns of L. pneumophila and L. longbeachae. Transmission Electron Microscopy (TEM) analysis of these lysates revealed the presence of numerous phages with diverse morphologies, with Myoviridae and Siphoviridae being the most common. Consistent with previous work, we observed only zones of confluent lysis on a host lawn following enrichment of samples from different environments (lakes, rivers, ponds, and etc.). No samples yielded single plaques and no zones of lysis could be further propagated.
Conclusion:
We have shown that diverse phages are associated with Legionella and have wide host range. Further work is ongoing to optimise phage purification, propagation, and development for therapeutic and diagnostic purposes.
Legionella is the causative agent of Legionnaires’ disease, a potentially fatal acute pneumonia with record high morbidity and mortality rates. Legionella has been shown to be resistant to antibiotics and its detection is difficult, leading to misdiagnosis, making treatment of this infection challenging. Clearly, there is a great need to identify novel and more effective therapeutic agents for this disease and more specific diagnostic tools for this pathogen. Bacteriophages (phages) are a potential tool to be exploited for this purpose. Here, we isolated and characterised lytic and temperate phages for further development as therapeutic agents and diagnostic tools Legionella spp.
Method:
A total of 180 water and sediment samples were collected from natural reservoirs and man-made systems, such as cooling towers, etc. The samples were first analysed for the presence of free phages using host range analysis, followed by Transmission Electron Microscopy (TEM). Subsequently, the same water samples were heat-treated and enriched for Legionella isolation. Bacteria isolated from the water samples were analysed using PCR targeting the macrophage infectivity potentiator (mip) gene, with resulting products sequenced to confirm the identity of the isolates.
Results and discussion:
After phage enrichment, 10 out of 180 water and sediment samples produced confluent zones of lysis on lawns of L. pneumophila and L. longbeachae. Transmission Electron Microscopy (TEM) analysis of these lysates revealed the presence of numerous phages with diverse morphologies, with Myoviridae and Siphoviridae being the most common. Consistent with previous work, we observed only zones of confluent lysis on a host lawn following enrichment of samples from different environments (lakes, rivers, ponds, and etc.). No samples yielded single plaques and no zones of lysis could be further propagated.
Conclusion:
We have shown that diverse phages are associated with Legionella and have wide host range. Further work is ongoing to optimise phage purification, propagation, and development for therapeutic and diagnostic purposes.
Reference:
Posters Day 2-T03-Pos-42
Session:
Posters Covering Ecology, Host population control, Co-Evolutionary dynamics and Subversion/Evasion of Host Defences
Presenters:
Neda Nezam Abadi
Session:
Day 2 Posters Covering: Ecology, Host population control, Co-evolutionary dynamics and Subversion/Evasion of host defences
Presentation type:
Poster presentation
Room:
Poster Halls
Date:
Tuesday, 19 July 2016
Time:
12:05 - 15:00