Efficacy of different antibiotic combinations on uropathogenic multi-drug resistant Escherichia coli

Using checkerboard titration method as well as time-kill curve technique, the potential synergy of combinations of beta-lactams [ceftazidime and cefepime], aminoglycosides [amikacin, gentamicin, and tobramycin] and fluoroquinolones [ciprofloxacin, levofloxacin, and ofloxacin] were compared against multidrug resistant uropathogenic Escherichia coli isolated from patients with urinary tract infections. In the checkerboard titration studies, none of 21 combinations demonstrated antagonism against 8 strains, five of the 21 combinations showed synergism for more than 40% of the test strains, i.e. ceftazidime tobramycin, ceftazidime levofloxacin, amikacin levofloxacin, amikacin with ofloxacin, and tobramycin with levofloxacin, synergy occurred more often with levofloxacin combined with amikacin [7/8 strains]. Corresponding to the respective fractional inhibitory concentration [FIC] indices, the bactericidal activity determined in combinations of amikacin with ceftazidime or levofloxacin at sub-minimum inhibitory concentrations produced a significant reduction in bacterial count [>/= 2 log 10 cfu/ml] observed within 6 hours of drug administration, at 24 hours, both combinations were bactericidal [reduction in colony count >/= 3 log 10]. Results of this study suggest that amirioglycosides [amikacin and or tobramycin] combination with levofloxacin or ceftazidime could be promising alternatives for the treatment of serious urinary tract infections due to multi drug resistant E. coli

antimicrobial activity of actinomycetes against multi-drug resistant bacteria

The study investigates the antibacterial and antifungal activity of some actinomycetes microorganisms. Twenty actinomycetes were isolated from different soils at various locations in Egypt. Cultural, morphological and physiological characteristic of this isolates indicated that they belong to Streptomyces sp. The isolates have antagonistic activity against different Gram negative and Gram positive multi-drug resistant bacteria and pathogenic fungi. Two isolates namely Streptomyces bobili FS-3 and Streptomyces poonensis FS-4 were further investigated. The potency of antimicrobial activity depend on incubation time, the nutritional factors such as carbon, nitrogen and phosphorus sources and environmental factors such a initial pH, medium capacity, size, type and age of inoculum