Efficacy of Combination of Meropenem with Amikacin, Ciprofloxacin, Gentamicin, and Nitrofurantoin against resistant E.coli isolated from patients with Urinary tract infections :(In vitro Study)

Escherichia coli is one of the most frequent causes of urinary tract infection. It was considered the most important bacterial family, which is related to Enterobacteraceae, which is the important pathogenic bacterium medically.Two hundred urine samples were collected from patients with urinary tract infections in AL-Kadhimia and AL-Yarmook teaching hospitals in Baghdad for a period between 22/11/2009 to 15/3/2010 the result is showed that 182 samples were positive for E. coli isolates bacterial culture which represent (41.7%) of the samples while (58.2%) of the isolates indicate the presence o different spp. including P. aeruginosa(16.4%), Proteus spp.(5.4%), Klebsiallas spp.(3.8%), Staph epidermidis(15.3%), Staph aureus(9.6%), Monillia(2.1%), and Enterobacter(2.7%). The aim of the present study is to isolate and characterize E. coli and other pathogenic bacteria from UTIs patients ,also to determine the lowest minimum inhibitory concentration (MICs) of single antimicrobial and antimicrobials combination for the highest resistant E. coli isolates, and also determination the best effective antimicrobial and antimicrobials combinations in resistant E.coli in UTI in vitro, finally to study some genetic characteristic of antimicrobial resistance of the highest resistant E.oli. E. coli identification depended on bacteriological morphology, biochemical testes in addition to API 20E system.The susceptibility of isolates to seventeen antimicrobials was also tested by using disk diffusion assay. The agents meropenem , nitrofurantoin , amikacin and imepenem were the most effective antimicrobials, while the other antimicrobials were twenty five isolates were selected according to their pattern of the highest resistance as those showed multi-drug resistances and tested to specify their minimum inhibitory concentration for (meropenem, amikacin, nitrofurantoin, gentamicin, and ciprofloxacin), meropenem was found to be the lowest MIC comparing with other The in vitro study also showed some effects of various combinations of five types of antimicrobials (meropenem, amikacin, nitrofurantoin, gentamicin, and ciprofloxacin) against twenty five E. coli isolates. The combination of meropenem with the other four types of antimicrobials showed high synergistic effect when 1/4+1/4 MIC for each antimicrobials were used. While combination of nitrofurantoin with amikacin or amikacin with ciprofloxacin showed high additive effect when 1/2+1/2 MIC for each antimicrobials were used. The plasmid profile for the (25) E. coli isolates were studied using Pure Yeild ™ plasmid Miniprep system- Cat.# A1220 – Promega- USA. In order to determine the presence of plasmid in antimicrobials rsistance.