Prevalence of Bacterial Pathogens and their Antimicrobial Susceptibility Patterns at a Tertiary Care Hospital in Riyadh

Abstract Objectives: The current study aimed to set up the prevalence of commonly isolated pathogens and their susceptibility patterns in a tertiary care reference center in Riyadh through a 3-year retrospective study. Materials and Methodology: Patient samples from two tertiary care hospitals with approximately 450 beds were submitted for culture and sensitivity to MDLab, Riyadh. Microsoft Office Excel was used to analyze all the data. Results: Among a total of 8389 positive cultures, urine was the most common sample submitted for bacterial culture over these 3 years, followed by pus and wounds. Gram-negative bacteria were prevalent compared to gram-positive bacteria. However, Staphylococcus aureus was the most commonly isolated pathogen from pus and wounds. From outpatients, Escherichia coli was the leading pathogen (50.5%), followed by Klebsiella and S. aureus (15.8% and 13.5%, respectively). In contrast, Pseudomonas was the most frequently isolated pathogen (20.8%) from hospitalized patients, followed by Klebsiella (18.7%) and E. coli (16%). Percent resistance was found to be higher in admitted patients as compared to walk-in patients. High resistance was noted in Acinetobacter baumannii complex to almost all classes of antibiotics among the gram-negative bacterial isolates. Oxacillin resistance ranged from 35% to 40% in Staphylococci . Conclusion: Overall, in our study, a high resistance of more than 30% up to 84% was noted in gram-negative bacterial isolates against the commonly used beta-lactam drugs and co-trimoxazole. A report from this type of local investigation is highly beneficial in guiding physicians on empirical therapy by providing insights into the level of antibiotic resistance within their specific settings.