ANALYSIS OF CLINICAL SAMPLES FOR E. COLI ALONG WITH MOLECULAR DOCKING OF PBP1B WITH CEFOPERAZONE AND CTX-M-14 WITH CEFTRIAXONE

ABSTRACT
Objective: To isolate E. coli from various clinical specimens, to analyze its prevalence and antimicrobial susceptibility
pattern. Implementation of molecular docking to observe binding orientation of drug molecules with bacterial proteins.
Study Design: Prevalence study.
Place and Duration of Study: Microbiology Laboratory, Department of Microbiology, Shaheed Benazir Bhutto Women
University Peshawar, from July 2014 to September 2014.
Methodology: Microbiological analysis of 80 clinical specimens comprising of urine, blood, pus, and sputum samples
were undertaken and collected aseptically in a sterile plastic containers. Blood agar, MacConkey agar and CLED
(Cysteine Lactose Electrolyte Deficient) agar were used as growth media for the culturing of microorganisms. Microor
¬ganisms were identified through Gram staining followed by citrate utilization, urease, and TS! (triple sugar iron)
tests. The isolates were then subjected to test antimicrobial susceptibility pattern. Bioinformatics tool such as docking
was applied to understand the structure-activity association of bacterial proteins and antibiotics.
Results: Out of 80 samples, 12 (15%) were substantiated as E. coli with higher prevalence rate in females (10%)
than males (5%) frequently in young age (up to 30 years). Amikacin (83.3%), cefoperazone (66.6%), and meropenen
(66.6%) appeared to be more sensitive while erythromycin (100%), ceftazidime (83.3%), and ceftriaxone (75%) showed
resistance than others. Among cephalosporins, cefoperazone was considerably active drug while ceftriaxone exhibited
resistance. These drugs when docked using hex server demonstrated a number of interactions. Amino acid residue
GLU166 is responsible for positioning cefoperazone to active site of PBP1b and restricting the bacterial cell to cause
infection. Whereas, amino acid residues ARG 153, THR149, GLY146, and ASP163 of beta-lactamase (CTX-M-14) make
important contacts with ceftriaxone in the receptor-ligand complex, which inhibited the drug from binding to sensitive
proteins in E. coli.
Conclusion: The study concluded that among other infections E. coli existed more in UT’s (20.9%) predominantly in
females frequently in young age. Hence, molecular docking is suspected to be applicable for recognizing the a