Phenotypic and molecular characterization of virulence factors of extra-intestinal pathogenic Escherichia coli isolated from patients of Peshawar, Pakistan.

Extra-Intestinal Escherichia coli (ExPEC) are important cause of Urinary Tract Infections (UTIs) and systemic infections. The purpose of this study was to investigate numerous ExPEC bacterial isolates for phenotypic virulence characteristics including hemolytic activity and resistance pattern and to observe their association with genetic traits via Polymerase Chain Reaction (PCR). A total of 367 ExPEC isolates were collected from patients admitted in Khyber Teaching Hospital (KTH) Peshawar, Pakistan. Standard techniques were used for identification of isolates, determination of hemolytic potential and antimicrobial susceptibility testing. PCR was used for screening of virulence genes using specific primers. A total of 367 ExPEC isolates were characterized, among which 62.7, 24.3, 7.1 and 6% were isolated from urine, pus, sputum and wound specimens, respectively. Majority of the isolates (82.8%) were hemolysin positive. Multi drug resistance pattern was shown by 41% of the isolates and harbored at least one virulence gene (71.7%), of which sat was the most prevalent (64.3%). The highest resistance was found to cefotaxime (99.2%), ampicillin (97.5%) and aztreonem (89.6%). 15 different virulence genes combinations were observed in the current study. A total of 16 virotypes (15 of positive virulence genes and one of no virulence gene) were observed in the current study. The current investigation showed a high prevalence of sat and hlyA genes among ExPEC isolate, suggesting a role of these genes in the pathogenesis of ExPEC.

Designing of potent inhibitors for metallo-beta-lactamases producing Escherichia coli in molecular specification hereto.

The rapid spread of Metallo-ß-Lactamases producing Gram-negative bacteria in Pakistan is alarming and novel inhibitors with multi inhibition potential are required. In the current study, an effort was made to identify the resistance genes of MBLs producing E. coli and single inhibitor was designed having the potential to block all resistant proteins. Results showed that out of 573 clinical isolates, 14.1% MBLs producers have NDM-1 (27.2%) and VIM (13.6%) gene. The isolates were resistant to MEM, AMP, AMC, FEP, CTX, LEV and ATM, while effective antibiotics were TGC, CO, FOS and AK with MICs ranging from 4 to >32µg/ml. RECAP synthesis was used for de-novo discovery of 1000 inhibitors and protein crystal structures were retrieved from PDB. Active sites were identified in each protein and to improve ADMET properties, Lipinski's rules of five was applied. Placement of the ligand was done by London dG algorithm implemented in MOE. For final refinement, GBVI/WSA dG algorithm was used. Based on docking score, visual inspection of ligands interaction with key residues, binding affinity and binding energy of ligands with proteins, 10 compounds were selected for MBLs proteins which presented best ADMET properties, binding energy and affinity than the reported ones.

Molecular epidemiology of antibiotic-resistant genes and potent inhibitors against TEM, CTX-M-14, CTX-M-15, and SHV-1 proteins of Escherichia coli in district Peshawar, Pakistan.

The Extended Spectrum Beta-Lactamases (ESBLs) producing bacteria is an issue of concern for clinicians resulting in minimize the treatment options. To overcome resistance mechanisms, novel inhibitors with good Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties must inhibit the ESBLs resistant genes. The current study aimed to identify the antibiotic resistance genes of ESBLs producing E. coli and a single inhibitor was designed to inhibit all the resistant proteins. The results showed that 42.9% ESBL producers had CTX-M (69.9%), TEM (63.4%), SHV (34.5%) and CTX-M-14 (17.5%) genes. The ESBLs producing isolates were resistant to cephalosporins, quinolones, and sulfonamide with Minimum Inhibitory Concentration (MICs) ranging from 64 to >256 µg/ml. To design multi inhibitory ligands, RECAP synthesis was used for the de-novo discovery of 1000 inhibitors database. Protein crystal structures were retrieved from Protein Data Base (PDB). Lipinski's rules of five were applied to the novel inhibitors database to improve the ADMET properties. The novel inhibitors database was selected for docking simulations. Placement of the ligand was used by the London dG algorithm implemented in Molecular Operating Environment (MOE), while GBVI/WSA dG algorithm was used for final refinement. Based on docking score, visual inspection of ligands interaction with key residues, binding affinity, and binding energy of ligands with proteins, ten compounds were selected for ESBLs proteins with best ADMET properties, binding energy, and binding affinity the reported ones. These hits compounds have unique scaffolds and are predicted to be a starting point for developing potent inhibitors against antibiotic-resistant proteins.