• Saqib Ali, Muhammad Aamir Aslam, Rabia Kanwar, Zain Mehmood, Muhammad Imran Arshad, and Sarfaraz Hussain.
• Institute of Microbiology, University of Agriculture Faisalabad, Faisalabad, 38000, Pakistan.
• Ir J Med Sci. 2024 Jun 1; 193 (3): 137713841377-1384.

BackgroundTyphoid fever is a fatal disease in humans that is caused by Salmonella typhi. S. typhi infections need immediate antibiotic therapy, and their extensive use has led to multidrug-resistant (MDR) pathogens. The use of bacteriophages is becoming a new way to treat these resistant bacteria. This research was directed to bacteriophage isolation against S. typhi and to determine phage-antibiotic synergism.AimsTo isolate bacteriophages targeting S. typhi, the causative agent of typhoid fever, and investigate their potential synergistic effects when combined with antibiotics.Study DesignA cross-sectional study.MethodsThe Widal test was positive; twenty diarrheal stool samples were taken, and for confirmation of S. typhi, different biochemical tests were performed. The disc-diffusion technique was used to determine antimicrobial resistance, and the double agar overlay method was used for bacteriophage isolation from sewage water against S. typhi. To test antibiotic-phage synergism, the S. typhi bacteria was treated by phages together with varying antibiotic concentrations.ResultsEleven samples were positive for S. typhi with black colonies on SS-agar. These were catalase and MR positive with alkali butt on TSI. Clear plaques were observed after the agar overlay. Isolated phages were stable at various pH and temperature levels. Synergism was observed on agar plate. The zone was enlarged when phages were combined with bacterial lawn culture and ciprofloxacin disk. Bacterial growth inhibition had a significant p-value of 0.03 in titration plates, with the phage-ciprofloxacin combination being more effective than the phage and antibiotic alone.ConclusionThe study highlights the synergistic effects of isolated bacteriophages with antibiotics, which are not only effective against S. typhi infection but also decrease antibiotic resistance.© 2023. The Author(s), under exclusive licence to Royal Academy of Medicine in Ireland.

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