Antibiotic Resistance Patterns and Plasmid Profiles of Escherichia coli Isolates from Clinical Specimens

Aim: The primary aims of this study were to investigate antibiotic resistance patterns and plasmid profile of antibiotic resistant Escherichia coli isolated from clinical specimens, and to find out a possible correlation between plasmids and antibiotic sensitivity patterns.

Methodology: Unrelated E. coli strains were isolated from different clinical specimens from different hospitals and primary health care centres in the Riyadh area Saudi Arabia. Antimicrobial susceptibility of E. coli isolates was determined using disc diffusion method against 12 com­monly used antimicrobial drugs. Plasmid DNA was extracted from lysed E. coli cells using Plasmid Miniprep kit, and visualised using Agarose gel electrophoresis.

Results: The results showed that isolated strains of E. coli were resistant to Cotrimoxazole (70%), Ampicillin (67%), nalidixic acid (51%), Cephalothin (27%), Agumentin and Nitrofurantoin (19%), Tetracycline and Ciprofloxacin (15%) and Gentamycin (12%). Plasmid analysis of clinical isolates showed the presence of 1 to 7 plasmids with size range of 1.9 to 21.1 Kb, as compared to control E. coli ATCC 25922 (size range of 2 to 19.5 Kb).

Conclusion: The results obtained in this study showed no direct correlation between the patterns of antibiotic resistance and plasmid profiles.