الفهرس | Only 14 pages are availabe for public view |
Abstract SOS is a bacterial stress response that aids the cell to overcome DNA damage. The SOS response is triggered by the accumulation of ssDNA, when cells try to replicate damaged DNA, after UV irradiation, treatment with antibiotics (fluoroquinolones, β-lactams or mitomycin C) or any other DNA damaging chemical. The problem of antimicrobial resistance in bacterial pathogens has been fairly described as a growing global crisis which has an established link with SOS response. Several commonly used antibiotics induce the SOS response, potentially hastening genetic change and the evolution to resistance of pathogenic populations. In the current work, the SOS response inducibility in different E. coli isolates was studied by testing for some SOS parameters as filamentous growth, RecA protein expression and prophage inducibility.The antimicrobial sensitivity of isolates for some commonly used antibiotics and biocides were tested and resistance profiles were made. The effect of SOS response on some of resistance development related processes in bacteria as mutation, transformation and genetic conjugal transfer was also studied trying to explore the link between SOS response and antimicrobial resistance. Results showed high resistance level to nine tested antibiotics: resistance to cefuroxime (66%) followed by tetracycline, ampicillin, rifampicin, gentamicin, ciprofloxacin, chloramphenicol and cefotaxime in percentages of 54.5%, 47.8%, 26.6%, 19.3%, 8.5%, 7.8% and 7.2% respectively; while imipenem showed the highest antibacterial effect with resistance percentage of 6.6%. Four isolates were found to be susceptible to all tested antibiotics and only one isolate was resistant to all tested antibiotics. The remaining isolates showed resistance to one or more antibiotics, thus 57, 44, 29, 4, 15, 5, 5, and one isolate, were resistant to one, two, three, four, five, six, seven, and eight antibiotics, respectively. |