The emergence of multi-drug resistant (MDR) bacterial strains, which are posing a global health threat has developed the interest of scientists to use bacteriophages instead of conventional antibiotics therapy. In light of an increased interest in the use of phage as a bacterial control agent, the study aimed to isolate and characterize lytic phages from sewage effluent. During the current study, bacteriophage AS1 was isolated from sewage effluent against E.coli S2. The lytic activity of phageAS1 was limited to E.coli S2 strain showing monovalent behavior. The calculated phage titer was 3.5×109 pfu/ml. PhageAS1 was stable at a wide range of pH and temperature. The maximum stability was recorded at 37ºC and pH 7.0, while showing its normal lytic activity at temperature 60ºC and from pH 5.0 to11.0 respectively. At temperature 70ºC, phage activity was somewhat reduced whereas, further increase in temperature and decrease or increase in pH completely inactivated the phage. From the current study, it was concluded that waste water is a best source for finding bacteriophages against multi-drug resistant bacterial strains and can be used as bacterial control agent.

Staphylococcus aureus is a notorious Gram-positive, non-spore-forming, opportunistic bacterium that causes a variety of infections including bacteremia, endocarditis, pneumonia, skin and soft tissue infections, and several others. Also, the overuse and misuse of drugs attributed to the crises of multidrug resistance especially in MRSA. Objective: Therefore, the aim of this study was to determine the prevalence rate of MRSA, antimicrobial susceptibility profiles of S. aureus, MRSA, and MSSA isolates to a variety of commonly used antibiotics, and its multidrug resistant patterns. Methods: Samples were collected from the microbiology department of HMC Peshawar, Pakistan. Antibiotic susceptibility patterns were determined under CLSI and EUCAST guideline, 2021 by following the Kirby-Bauer disc diffusion method. Results: Out of 106 S. aureus clinical isolates, 83 (78.3%) isolates were identified as MRSA and 23 (21.7%) were MSSA. In MRSA high resistance was exhibited to Penicillin G and cefoxitin (100%), followed by erythromycin 84.34% and ciprofloxacin 79.52%. Meanwhile low resistance was observed to doxycycline 19.28% followed by chloramphenicol 14.46%, teicoplanin and linezolid 2.41% for each respectively. High sensitivity in MRSA isolates was exhibited to linezolid 97.59% followed by teicoplanin 95.18%, chloramphenicol 85.54%, doxycycline 80.72% and fusidic acid 74.70%. A total of n=94 (88.67%) isolates were characterized as MDR. Conclusions: In conclusion, the most effective antibiotics used to treat S. aureus infections were linezolid, teicoplanin, chloramphenicol, doxycycline, fusidic acid, and gentamycin. In addition, the current study also noticed a significant prevalence of resistance to several antibiotics, emphasizing the importance of antibiotic usage monitoring.