Decreased prevalence of virulence factors among ciprofloxacin-resistant uropathogenic Escherichia coli isolates.

Ciprofloxacin resistance was identified in 18% and 6% of consecutively collected, clinically significant urinary tract isolates of Escherichia coli from inpatients and outpatients, respectively. In comparison to ciprofloxacin-susceptible isolates, there were fewer resistant isolates that expressed beta-hemolysis (outpatient, 9% versus 87%, P < 0.0001; inpatient, 4% versus 76%, P < 0.0001) and that had a papEF genotype, genes encoding P fimbriae (outpatient, 30% versus 70%, P = 0.0004; inpatient, 26% versus 70%, P < 0.0001).

In vitro activities of fluoroquinolones against antibiotic-resistant blood culture isolates of viridans group streptococci from across Canada.

Among 418 blood culture isolates of viridans group streptococci obtained between 1995 and 1997, the in vitro rates of nonsusceptibility to penicillin, erythromycin, tetracycline, and trimethoprim-sulfamethoxazole were 28, 29, 24, and 14%, respectively. The most prevalent group (125 strains) was Streptococcus mitis, followed by Streptococcus sanguis (56 strains). For 236 (56%) strains resistant to one or more antibiotics, the ciprofloxacin MIC at which 90% of the isolates were inhibited (MIC(90)) was 4 microg/ml, whereas the MIC(90)s of trovafloxacin, grepafloxacin, and gatifloxacin were 0.25 microg/ml.

Activity of BMS-284756, a novel des-fluoro(6) quinolone, against Staphylococcus aureus, including contributions of mutations to quinolone resistance.

The in vitro activity of BMS-284756 against 602 Staphylococcus aureus isolates, including 152 that were both methicillin and ciprofloxacin resistant (MIC > or = 4 microg/ml), was determined. For ciprofloxacin-susceptible and nonsusceptible isolates, the MICs at which 50% of organisms were inhibited were 0.015 and 2 microg/ml and the MICs at which 90% of organisms were inhibited were 0.03 and 4 microg/ml, respectively.