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

Physiological and biochemical studies on phytopathogenic bacteria isolated from cucumber in Egypt

Thirty phytopathogenic bacterial isolates were obtained from diseased cucumber plants [Cucumis sativus]. These isolates were highly pathogenic, capable of inducing angular leaf spots as well as wilting of cucumber seedlings within 3-6 days after inoculation. The diagnostic tests including colony morphology, pathogenicity trials and different physiological tests showed that they belonged to Pseudomonas syringae pv lachrymans. Inoculating three weeks old cucumber seedlings with the most virulent isolate resulted in a reduction in dry weight, water content and both shoot and root length to a level below that of the control