OBJECTIVES Extensive use of quinolones has been associated with raising level of resistance. In the current, we focused on assessing the prevalence of Escherichia coli resistance to quinolones and frequency of qnrA, qnrB and qnrS in non ESBLs (extended spectrum beta-lactamases) and ESBLs producing E. coli with blaSHV and blaTEM. MATERIALS AND METHODS One hundred and fifty E. coli isolates wer...

Burkholderia is a bacterial genus comprising several pathogenic species, including two species highly pathogenic for humans, B. pseudomallei and B. mallei. B. thailandensis is a weakly pathogenic species closely related to both B. pseudomallei and B. mallei. It is used as a study model. These bacteria are able to exhibit multiple resistance mechanisms towards various families of antibiotics. By...

DNA gyrase is a target of quinolone antibacterial agents, but the molecular details of the quinolone-gyrase interaction are not clear. Quinolone resistance mutations frequently occur at residues Ser and Asp of the gyrase A subunit, suggesting that these residues are involved in drug binding. Single and double alanine substitutions were created at these positions (Ala, Ala, and Ala Ala), and the...

INTRODUCTION In the past two decades members of the genus Enterococcus have emerged as important nosocomial pathogens worldwide. This study prospectively analyzed the distribution of species and trends in antimicrobial resistance among clinical isolates of enterococci in a Brazilian tertiary hospital from 2006-2009. METHODS Enterococcal species were identified by conventional biochemical test...

The parC and gyrA genes of 73 ciprofloxacin-resistant and 6 ciprofloxacin-susceptible Enterococcus faecium clinical isolates were partly sequenced. Alterations in ParC and GyrA, possibly in combination with other resistance mechanisms, severely restricted the in vitro activities of the nine quinolones tested. For all isolates, clinafloxacin and sitafloxacin showed the best activities.

Resistance of Helicobacter pylori to the standard therapeutic antimicrobials (clarithromycin, metronidazole, amoxicillin [AMX], and tetracycline) (9) has been demonstrated; therefore, there is an urgent need to introduce other treatment options. Fluoroquinolones, such as levofloxacin (LVX) and gatifloxacin (GAT), have been evaluated as an alternative to standard antibiotics against H. pylori. A...

The incidence of penicillin resistance in pneumococci is increasing in the USA, having risen from <5% before 1989 to >35% in 1997. There has also been a shift in the ratio of intermediate to high-level resistance from 3 or 4:1 to 2 or 1:1. Multidrug resistance and resistance to macrolides and fluoroquinolones in pneumococci is also a matter of concern. The implications for empirical treatment o...

Quinolone resistance normally arises by mutations in the chromosomal genes for type II topoisomerases and by changes in the expression of proteins that control the accumulation of quinolones inside bacteria. A novel mechanism of plasmid-mediated quinolone resistance was recently reported that involves DNA gyrase protection by a pentapeptide repeat family member called Qnr. This family includes ...

ABSTRACT Background and Objectives: One major source of antibiotic contamination in the sea is from aquaculture. We monitored concentration commonly used classes resistance genes ( tet (M), sul1, sul2 sul3 ) aquaculture farms Peninsular Malaysia. Methods: Antibiotic residues were quantified using high-performance liquid chromatography real-time PCR respectively. Risk quotients European technica...

The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps in Pseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump compone...