Quinolones rapidly kill bacteria by two mechanisms, one that requires protein synthesis and one that does not. The latter, which is measured as lethal action in the presence of the protein synthesis inhibitor chloramphenicol, is enhanced by N-1 cyclopropyl and C-8 methoxy substituents, as seen with the highly lethal compound PD161144. In some compounds, such as levofloxacin, the N-1 and C-8 sub...

OBJECTIVES Several observational studies have been published investigating the association between oral fluoroquinolone use and the development of retinal detachment; however, the findings are not concordant. This study is a meta-analysis of the existing literature and estimates the overall absolute risk of such an event. METHODS Electronic databases were searched for observational studies on...

BACKGROUND Fluoroquinolones are among the most commonly prescribed antimicrobials and are an important risk factor for colonization and infection with fluoroquinolone-resistant gram-negative bacilli and for Clostridium difficile infection (CDI). In this study, our aim was to determine current patterns of inappropriate fluoroquinolone prescribing among hospitalized patients, and to test the hypo...

BACKGROUND Antibiotic resistance has necessitated fluoroquinolone use but little is known about the selective forces and resistance trajectory in malaria-endemic settings, where selection from the antimalarial chloroquine for fluoroquinolone-resistant bacteria has been proposed. METHODS Antimicrobial resistance was studied in fecal Escherichia coli isolates in a Nigerian community. Quinolone-...

BACKGROUND Transrectal ultrasound-guided prostate biopsies (TRUSBx), in spite of being one of the most frequently performed urological office procedures, are associated with a spectrum of complications, most significantly including infection. The aim of the study is to evaluate the prevalence of fluoroquinolone-resistant bacteria in rectal swabs from our local population prior to TRUSBx and to ...

BACKGROUND Streptococcus pneumoniae is the leading cause of community-acquired pneumonia (CAP). High global incidence of macrolide and penicillin resistance has been reported, whereas fluoroquinolone resistance is uncommon. Current guidelines for suspected CAP in patients with co-morbidity factors and recent antibiotic therapy recommend initial empiric therapy using one fluoroquinolone or one m...

Fluoroquinolone MICs are increased through the acquisition of chromosomal mutations in the genes encoding gyrase (gyrA and gyrB) and topoisomerase IV (parC and parE), increased levels of the multidrug efflux pump AcrAB, and the plasmid-borne genes aac(6')-Ib-cr and the qnr variants in Escherichia coli. In the accompanying report, we found that ciprofloxacin, gatifloxacin, levofloxacin, and norf...

Over 124 methicillin-susceptible Staphylococcus aureus 0/74 fluoroquinolone-susceptible versus 5/50 fluoroquinolone-resistant isolates were hypermutable. Hypermutable isolates combined mutations in gyrA, parC, and/or parE genes. One strain had a large deletion of the mutator mutS and mutL genes. No relevant mutation in mutS and mutL genes was found in the other isolates.

Fluoroquinolone-resistant Campylobacter jejuni has been observed worldwide and is now being seen in the United States. Among patients in our health-care system in Pennsylvania, fluoroquinolone-resistant C. jejuni were not observed from 1982 to 1992; however, resistance increased to 40.5% in 2001. Resistance to erythromycin remains at a low level (<5%).

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.