Sixty extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from rivers and lakes in Switzerland were screened for individual strains additionally exhibiting a reduced quinolone susceptibility phenotype. Totally, 42 such isolates were found and further characterized for their molecular (fluoro)quinolone resistance mechanisms. PCR and sequence analysis were performed to identi...

In Denmark surveillance of the in vitro susceptibility to ciprofloxacin of Neisseria gonorrhoeae was established in 1990. The proportion of N. gonorrhoeae strains with decreased susceptibility or resistance to ciprofloxacin (MIC >/= 0.06 microg/ml) was low (0.3 to 2.3%) up to 1995. Between 1995 and 1998 the rate of less-susceptible and resistant strains rose from 6.9 to 13.2%. Among ciprofloxac...

OBJECTIVES Mutations in the gyrase genes cause fluoroquinolone resistance in Mycobacterium tuberculosis. However, the predictive value of these markers for clinical outcomes in patients with MDR-TB is unknown to date. The objective of this study was to determine molecular markers and breakpoints predicting second-line treatment outcomes in M. tuberculosis patients treated with fourth-generation...

The occurrence of mutations in the genes coding for gyrase (gyrA and gyrB) and topoisomerase IV (parE and parC) of Salmonella typhimurium experimental mutants selected in vitro and in vivo and of 138 nalidixic acid-resistant Salmonella field isolates was investigated. The sequencing of the quinolone resistance-determining region of these genes in highly fluoroquinolone-resistant mutants (MICs o...

PURPOSE Using radiobiological modelling to estimate normal tissue toxicity, this study investigates the effects of dose escalation for concurrent chemoradiation therapy (CRT) in lower third oesophageal tumours on the stomach. METHODS AND MATERIALS 10 patients with lower third oesophageal cancer were selected from the SCOPE 1 database (ISCRT47718479) with a mean planning target volume (PTV) of...

We examined the response of Streptococcus pneumoniae 7785 to clinafloxacin, a novel C-8-substituted fluoroquinolone which is being developed as an antipneumococcal agent. Clinafloxacin was highly active against S. pneumoniae 7785 (MIC, 0.125 microg/ml), and neither gyrA nor parC quinolone resistance mutations alone had much effect on this activity. A combination of both mutations was needed to ...

The MICs of ofloxacin for 743 strains of Escherichia coli isolated from 1988 to 1994 were determined by testing. The strains were from patients with urinary tract infections complicated by functional or anatomical disorders of the urinary tract. Those determined to be ofloxacin resistant (MIC, > or =12.5 microg/ml) comprised 3 of 395 strains (1.3%) from the 1988 to 1990 group, 2 of 166 strains ...

In defined, isogenic strains, at least three mutations, two of which must be in gyrA, were required to exceed the CLSI breakpoint for fluoroquinolone resistance. Strains with double mutations in both gyrA and parC had even higher MICs of fluoroquinolones than strains with totals of three mutations.

The gyrA and parC genes of 31 clinical isolates of Enterococcus faecalis, including fluoroquinolone-resistant isolates, were partially sequenced and analyzed for target alterations. Topoisomerase IV may be a primary target in E. faecalis, but high-level fluoroquinolone resistance was associated with simultaneous alterations in both GyrA and ParC.