no. ISTN3X; 96% identical), comprising one of Tn3-like inverted repeats and putative coding regions for transposase, resolvase (also called repressor), and ampicillin resistance. The resistance gene encodes a TEM-1 type β-lactamase. (The sequence has been registered to DDBJ/GenBank/ EMBL with accession no. AB103092.) Conjugative transferability of p981123 between S. Enteritidis strains was exam...

BACKGROUND Nalidixic acid resistance among Salmonella Typhimurium clinical isolates has steadily increased, whereas the level of ciprofloxacin resistance remains low. The main objective of this study was to characterize the fluoroquinolone resistance mechanisms acquired in a S. Typhimurium mutant selected with ciprofloxacin from a susceptible isolate and to investigate its invasion ability. M...

OBJECTIVES The aim of this study was to assess the prevalence rate of primary fluoroquinolone resistance in Helicobacter pylori isolates from Korean patients over the past 16 years. METHODS One hundred and thirty-five strains of H. pylori (34 strains in 1987, 36 in 1994 and 65 in 2003) were isolated from antral gastric mucosal biopsy specimens. The determination of MICs for the H. pylori isol...

Title of Dissertation: CHARACTERIZATION AND MOLECULAR MECHANISMS OF ANTIMICROBIAL RESISTANCE IN FOODBORNE PATHOGENS Sheng Chen, Doctor of Philosophy, 2004 Dissertation directed by: Associate Professor Jianghong Meng Department of Nutrition and Food Science The emergence of antimicrobial resistance bacteria in both the medical and agricultural fields has become a serious problem worldwide. The u...

The incidence of infections due to extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae (ESBL-EK) has increased markedly in recent years. Treatment is difficult because of frequent multidrug resistance. Although fluoroquinolones offer effective therapy for ESBL-EK infections, their usefulness is threatened by increasing fluoroquinolone resistance. To iden...

Molecular characterization of fluoroquinolone-resistant Streptococcus pneumoniae in Canada was conducted from 1997 to 2005. Over the course of the study, 205 ciprofloxacin-resistant isolates were evaluated for ParC and GyrA quinolone resistance-determining region (QRDR) substitutions, substitutions in the full genes of ParC, ParE, and GyrA, reserpine sensitivity, and serotype and by pulsed-fiel...

BACKGROUND Molecular resistance testing fails to explain all fluoroquinolone resistance, with a continued need for a suitable rapid phenotypic drug susceptibility testing method. OBJECTIVE To evaluate the optimal method for phenotypic fluoroquinolone susceptibility testing. METHODS Using Löwenstein-Jensen medium, Middlebrook 7H11 agar, BACTEC-MGIT 960 and the resazurin microtitre plate assa...

The frequency of fluoroquinolone-resistant Streptococcus pneumoniae has increased as fluoroquinolone administration for treatment of respiratory tract infections has increased. Levofloxacin treatment failed in a patient who had pneumococcal pneumonia and had received three previous courses of levofloxacin therapy. Susceptibility testing revealed high-level resistance to levofloxacin (minimum in...

Escherichia coli strains from patients with uncomplicated urinary tract infections were examined by DNA sequencing for fluoroquinolone resistance-associated mutations in six genes: gyrA, gyrB, parC, parE, marOR, and acrR. The 54 strains analyzed had a susceptibility range distributed across 15 dilutions of the fluoroquinolone MICs. There was a correlation between the fluoroquinolone MIC and the...