Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens

Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens

Colibacillosis is one of the main causes of economic losses in the poultry industry worldwide. Although antibiotics have been used to control this infection, the emergence of antibiotic resistant bacteria poses a threat to animal and human health. Therefore, an alternative to antibiotics is urgently...

Full description

Bibliographic Details
Main Author: Lau, Gee Leng
Format: Thesis
Language:English
Published: 2010
Online Access:http://psasir.upm.edu.my/id/eprint/19426/
http://psasir.upm.edu.my/id/eprint/19426/1/FBSB_2010_11_F.pdf
id upm-19426
recordtype eprints
spelling upm-194262015-05-22T02:00:32Z http://psasir.upm.edu.my/id/eprint/19426/ Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens Lau, Gee Leng Colibacillosis is one of the main causes of economic losses in the poultry industry worldwide. Although antibiotics have been used to control this infection, the emergence of antibiotic resistant bacteria poses a threat to animal and human health. Therefore, an alternative to antibiotics is urgently required. In the present study, two bacteriophages, namely ØEC1 and ØEC2, which were lytic against avian pathogenic Escherichia coli (APEC) O78:K80 and O1:K1 (causative agent of colibacillosis), respectively, were isolated from chickens’ fecal samples. These two phages are specific to their target host bacteria and do not lyse other tested bacteria such as Escherichia coli, Salmonella, Campylobacter, Lactobacillus and several gastrointestinal microflora. Examination by transmission electron microscope revealed that ØEC1 and ØEC2 belong to Podoviridae and Tectiviriae family, respectively. Both phages demonstrated an optimum multiplicity of infection (MOI) of 0.1 to 1. Based on the results of single-step growth, the latent period of ØEC1 was 25 min with a burst size of 200 particles per infected cell. ØEC2 showed a shorter latent period of 7 min and a burst size of 2-3 particles per infected cell. Under the experimental condition, the highest adsorption rate for ØEC1 was 99.9% and ØEC2 was 82.2%. Both phages demonstrated similar optimum pH (pH 6.0 - pH 9.0) for effective phage lytic activity. The optimum temperature for ØEC1 lytic activity was found to be in the range of 25°C to 41°C while ØEC2 demonstrated the highest lytic activity at 37°C. These results indicated that ØEC1 could be a more virulent phage in comparison to ØEC2. Thus, the efficacy of ØEC1 as therapeutic agent against APEC O78:K80 was evaluated in vivo in chickens. Results from the in vivo study showed that treatment with ØEC1 could reduce the mortality rate of E. coli challenged birds by 70% during the 3 week experimental period. The body weight of birds from the E. coli challenged group treated with ØEC1 was not significantly different from those of negative control groups on day 14 post-infection and was 15.4% higher than that of untreated E. coli challenged group on day 21 post-infection. Based on the gross lesion observations for airsacculitis, pericarditis and perihepatitis, the infections were found to be less severe in the treated E. coli challenged group. The total viable cell counts of E. coli in the lungs of treated E. coli challenged birds was approximately 22-fold lower than that of untreated challenged birds at day 1 post-infection. E. coli isolation frequency from blood and organs was also found to be lower in treated birds. These results suggested that ØEC1 is effective in vivo and could be an alternative to antibiotic to treat colibacillosis in chickens. 2010-10 Thesis NonPeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/19426/1/FBSB_2010_11_F.pdf Lau, Gee Leng (2010) Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens. Masters thesis, Universiti Putra Malaysia.
repository_type Digital Repository
institution_category Local University
institution Universiti Putra Malaysia
building UPM Institutional Repository
collection Online Access
language English
description Colibacillosis is one of the main causes of economic losses in the poultry industry worldwide. Although antibiotics have been used to control this infection, the emergence of antibiotic resistant bacteria poses a threat to animal and human health. Therefore, an alternative to antibiotics is urgently required. In the present study, two bacteriophages, namely ØEC1 and ØEC2, which were lytic against avian pathogenic Escherichia coli (APEC) O78:K80 and O1:K1 (causative agent of colibacillosis), respectively, were isolated from chickens’ fecal samples. These two phages are specific to their target host bacteria and do not lyse other tested bacteria such as Escherichia coli, Salmonella, Campylobacter, Lactobacillus and several gastrointestinal microflora. Examination by transmission electron microscope revealed that ØEC1 and ØEC2 belong to Podoviridae and Tectiviriae family, respectively. Both phages demonstrated an optimum multiplicity of infection (MOI) of 0.1 to 1. Based on the results of single-step growth, the latent period of ØEC1 was 25 min with a burst size of 200 particles per infected cell. ØEC2 showed a shorter latent period of 7 min and a burst size of 2-3 particles per infected cell. Under the experimental condition, the highest adsorption rate for ØEC1 was 99.9% and ØEC2 was 82.2%. Both phages demonstrated similar optimum pH (pH 6.0 - pH 9.0) for effective phage lytic activity. The optimum temperature for ØEC1 lytic activity was found to be in the range of 25°C to 41°C while ØEC2 demonstrated the highest lytic activity at 37°C. These results indicated that ØEC1 could be a more virulent phage in comparison to ØEC2. Thus, the efficacy of ØEC1 as therapeutic agent against APEC O78:K80 was evaluated in vivo in chickens. Results from the in vivo study showed that treatment with ØEC1 could reduce the mortality rate of E. coli challenged birds by 70% during the 3 week experimental period. The body weight of birds from the E. coli challenged group treated with ØEC1 was not significantly different from those of negative control groups on day 14 post-infection and was 15.4% higher than that of untreated E. coli challenged group on day 21 post-infection. Based on the gross lesion observations for airsacculitis, pericarditis and perihepatitis, the infections were found to be less severe in the treated E. coli challenged group. The total viable cell counts of E. coli in the lungs of treated E. coli challenged birds was approximately 22-fold lower than that of untreated challenged birds at day 1 post-infection. E. coli isolation frequency from blood and organs was also found to be lower in treated birds. These results suggested that ØEC1 is effective in vivo and could be an alternative to antibiotic to treat colibacillosis in chickens.
format Thesis
author Lau, Gee Leng
spellingShingle Lau, Gee Leng
Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
author_facet Lau, Gee Leng
author_sort Lau, Gee Leng
title Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
title_short Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
title_full Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
title_fullStr Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
title_full_unstemmed Isolation, Characterisation And Therapeutic Efficacy of Bacteriophage Isolates Used Against Avian Pathogenic Escherichia coli in Broiler Chickens
title_sort isolation, characterisation and therapeutic efficacy of bacteriophage isolates used against avian pathogenic escherichia coli in broiler chickens
publishDate 2010
url http://psasir.upm.edu.my/id/eprint/19426/
http://psasir.upm.edu.my/id/eprint/19426/1/FBSB_2010_11_F.pdf
first_indexed 2018-09-07T14:09:12Z
last_indexed 2018-09-07T14:09:12Z
_version_ 1610958086783107072

Similar Items