Rida Haroon Durrani; Ali Ahmad Sheikh; Masood Rabbani; Muti-ur-Rehman Khan; Muhammad Ilyas Riaz; Muhammad Anas Naeem; Salman Ashraf Chattha; Aleena Kokab; Munazzah Maqbool; Muhammad Athar Abbas; Naila Siddique
Volume 13, Issue 4 , December 2022, , Pages 481-487
Abstract
The emergence and spread of multidrug resistance among pathogens of the agro-food sector is increasing at an alarming rate, which has directed attention to the search for alternative to antibiotic therapy. The present work studied the physiological and population dynamics of lytic bacteriophages against ...
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The emergence and spread of multidrug resistance among pathogens of the agro-food sector is increasing at an alarming rate, which has directed attention to the search for alternative to antibiotic therapy. The present work studied the physiological and population dynamics of lytic bacteriophages against avian-adapted Salmonella. Out of 28 positive samples, four bacteriophage isolates (SalØ-ABF37, SalØ-RCMPF12, SalØ-MCOH26, SalØ-DNLS42) were selected based on their ability to clearly lyse bacterial test strains. The isolates propagated were active against closely related D1 serotypes, i.e., S. Enteritidis and S. Typhimurium, with no heterologous activity against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 23235. Each of the monophage suspension and cocktail efficiently suppressed the bacterial count from exponential increase in comparison to the untreated bacterial control. The bacterial turbidity was recorded as 0.244 at λ600 during 400 min of co-incubation, in contrast to bacterial control showing λ600 = 0.669. The latent period was recorded to be 25, 35, 25 and 30 for SalØ-ABF37, SalØ-RCMPF12, SalØ-MCOH26 and SalØ-DNLS42, with 73.00, 97.00, 132 and 75.00 PFU cell-1, respectively. The highest lytic activity was seen at 37.00 ˚C - 42.00 ˚C, with phage particle count being fairly stable at pH 3.00 - 9.00. Each of the isolates possessed dsDNA by being resistant to RNase A. The current study concludes that lytic phages are promising alternative to combat multidrug resistant superbugs. The physiological characterization and bacterial growth inhibition are important parameters in standardization of phage therapy.
Maryam Ansari-Lari; Shahram Shekarforoush; Samira Mehrshad; Hosna Safari
Volume 5, Issue 1 , March 2014, , Pages 65-68
Abstract
Salmonella spp. are important food borne pathogens worldwide that frequently infect poultry flocks. This cross-sectional study was conducted to determine the prevalence of Salmonella spp. colonization in broiler flocks in Shiraz (southern Iran) and to find the possible association of infection status ...
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Salmonella spp. are important food borne pathogens worldwide that frequently infect poultry flocks. This cross-sectional study was conducted to determine the prevalence of Salmonella spp. colonization in broiler flocks in Shiraz (southern Iran) and to find the possible association of infection status with some potential risk factors including vaccination program and use of antibiotics. During October 2009 to April 2010, a total of 40 broiler flocks were selected in slaughterhouse and 20 cloacae contents were collected from each flock. Every five cloacae contents were pooled and investigated for Salmonella spp. using appropriate culture methods. The flock was considered positive if any of the pooled samples turned positive in culture. Statistical analysis was performed using multiple logistic regression. Nine out of 40 flocks (22.50%, 95% CI: 9-36) were positive for Salmonella spp. colonization. Nearly 75.00% of flock owners reported that they used antibiotics during production period, more frequently fluoroquinolones, combination of trimethoprim-sulfonamides (TMP/SU) and tetracycline. Nearly 60.00% of the flocks which had used TMP/SU were positive for Salmonella spp. compared with 10.00% of the flocks which did not use this antibiotic (p = 0.006). Increasing flock age was associated with a decreased chance of Salmonella spp. detection (p = 0.003). In flocks which received infectious bronchitis vaccine, 36.00% were positive for Salmonella spp. whereas this was 15.00% for flocks which did not receive this vaccine (p = 0.08). Careful monitoring of antibiotics use and further studies to determine the most appropriate vaccination program in the field is recommended.