Abdul Haseeb,1 Zikria Saleem,2 Ummara Altaf,3 Narjis Batool,4 Brian Godman,5– 7 Umar Ahsan,8 Mehreen Ashiq,9 Mutiba Razzaq,9 Rabia Hanif,9 Zill E-Huma,9 Afreenish Amir,10 Mohammad Akbar Hossain,11 Mohamed Raafat,12 Rozan Mohammad Radwan,13 Muhammad Shahid Iqbal,14 Sairah Hafeez Kamran15 1Department of Clinical Pharmacy, College of Pharmacy, Umm AL-Qura University, Makkah, Saudi Arabia; 2Department of Pharmacy Practice, Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan; 3Department of Pharmacy, Ghurki Trust Teaching Hospital, Lahore, Pakistan; 4Australian Institute of Health Innovation, Center of Health Systems and Safety Research, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia; 5Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, UK; 6School of Pharmacy, Sefako Makgatho Health Sciences University, Pretoria, South Africa; 7Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates; 8Department of Infection Prevention and Control, Al Noor Specialist Hospital, Ministry of health, Makkah, Kingdom of Saudi Arabia; 9Faculty of Pharmacy, The University of Lahore, Lahore, Pakistan; 10Department of Microbiology, National University of Medical Sciences, Rawalpindi, Pakistan; 11Department of Pharmacology and Toxicology, Faculty of Medicine in Al-Qunfudah, Umm Al-Qura University, Makkah, Kingdom of Saudi Arabia; 12Department of Pharmacology and Toxicology, College of Pharmacy, Umm AL-Qura University, Makkah, Saudi Arabia; 13Pharmaceutical Care Department, Al Noor Specialist Hospital, Ministry of Health, Makkah, Saudi Arabia; 14Department of Clinical Pharmacy, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj, Saudi Arabia; 15Institute of Pharmacy, Lahore College for Women University, Lahore, PakistanCorrespondence: Zikria Saleem, Department of Pharmacy Practice, Faculty of Pharmacy, Bahauddin Zakariya University, Multan, Pakistan, Email xikria@gmail.comBackground: Antibiotic de-escalation is a key element of antimicrobial stewardship programs that restrict the spread and emergence of resistance. This study was performed to evaluate the impact of positive culture sensitivity reports of E. coli or Methicillin sensitive Staphylococcus aureus (MSSA) on de-escalation of antibiotic therapy.Methods: This prospective observational study was performed on 256 infected patients. The samples were obtained principally from the pus of infected sites for the identification of pathogens and culture-sensitivity testing. The data were collected from patient medical files, which included their demographic data, sample type, causative microbe and antimicrobial treatment as empiric or definitive treatment based on cultures. Data were analyzed using SPSS.Results: Of 256 isolated microbes, 138 (53.9%) were MSSA and 118 were E. coli (46.1%). MSSA showed 100% sensitivity to cefoxitin, oxacillin, vancomycin, fosfomycin, colistin and more than 90% to linezolid (95.3%), tigecycline (93.1%), chloramphenicol (92.2%) and amikacin (90.2%). E. coli showed 100% sensitivity to only fosfomycin and more than 90% to colistin (96.7%), polymyxin-B (95.1%) and tigecycline (92.9%). The high use of cefoperazone+sulbactam (151), amikacin (149), ceftriaxone (33), metronidazole (30) and piperacillin + tazobactam (22) was seen with empiric prescribing. Following susceptibility testing, the most common antibiotics prescribed for E. coli were meropenem IV (34), amikacin (34), ciprofloxacin (29) and cefoperazone+sulbactam (25). For MSSA cases, linezolid (48), clindamycin (30), cefoperazone+ sulbactam IV (16) and amikacin (15) was used commonly. Overall, there was 23% reduction in antibiotic use in case of E. coli and 43% reduction in MSSA cases.Conclusion: Culture sensitivity reports helped in the de-escalation of antimicrobial therapy, reducing the prescribing of especially broad-spectrum antibiotics. Consequently, it is recommended that local hospital guidelines be developed based on local antimicrobial susceptibility patterns while preventing the unnecessary use of broad-spectrum antibiotics for empiric treatment.Keywords: antimicrobial resistance, antimicrobial stewardship, culture sensitivity reports, definitive treatment, empirical treatment, de-escalation, Pakistan