Two-component signal transduction systems (TCSs), utilized extensively by bacteria and archaea, are involved in the rapid adaptation of the organisms to fluctuating environments. A typical TCS transduces the signal by a phosphorelay between the sensor histidine kinase and its cognate response regulator. Recently, small-sized proteins that link TCSs have been reported and are called "connectors....

Foot-and-mouth disease virus (FMDV) particles lose infectivity due to their disassembly at pH values slightly below neutrality. This acid-dependent disassembly process is required for viral RNA release inside endosomes. To study the molecular determinants of viral resistance to acid-induced disassembly, six FMDV variants with increased resistance to acid inactivation were isolated. Infection by...

introduction: stenotrophomonas maltophilia is a nosocomial multi drug resistant opportunistic pathogen which causes infections in vulnerable patients with cancer, cystic fibrosis and indwelling catheters. methods: 45 clinical s. maltophilia isolates were collected from blood samples and identified by biochemical tests. susceptibility to different antibiotics including co-trimoxazole, levofloxac...

Enterohemorrhagic strains of Escherichia coli must pass through the acidic gastric barrier to cause gastrointestinal disease. Taking into account the apparent low infectious dose of enterohemorrhagic E. coli, 11 O157:H7 strains and 4 commensal strains of E. coli were tested for their abilities to survive extreme acid exposures (pH 3). Three previously characterized acid resistance systems were ...

A total of 24,591 nonhuman salmonella strains isolated in Germany between 1986 and 1998 were examined for their resistance to nalidixic acid by an agar diffusion method. The rate of resistance (inhibition zone, </=13 mm) ranged from 0.2% in 1986 to a peak of 14. 8% in 1990. Between 1991 and 1998 the MICs for nalidixic acid-resistant strains ranged from more than 256 microg/ml for nalidixic acid...

OBJECTIVES To determine MICs of fusidic acid for and identify genetic determinants of resistance in Staphylococcus cohnii isolates. METHODS Susceptibility to fusidic acid was determined by the standard agar dilution method in 24 S. cohnii subsp. urealyticus clinical isolates, 7 S. cohnii subsp. cohnii clinical isolates and 2 reference strains. Sequencing of a novel resistance determinant, fus...

BACKGROUND Fusaric acid (5-butylpicolinic acid), a mycotoxin, is noxious to some microorganisms. Stenotrophomonas maltophilia displays an intrinsic resistance to fusaric acid. This study aims to elucidate the mechanism responsible for the intrinsic fusaric acid resistance in S. maltophilia. METHODOLOGY A putative fusaric acid resistance-involved regulon fuaR-fuaABC was identified by the surve...

Escherichia coli has an ability, rare among the Enterobacteriaceae, to survive extreme acid stress under various host (e.g., human stomach) and nonhost (e.g., apple cider) conditions. Previous microarray studies have exposed a cluster of 12 genes at 79 centisomes collectively called an acid fitness island (AFI). Four AFI genes, gadA, gadX, gadW, and gadE, were already known to be involved in an...

Background & Aims: One of the most common causes of bacterial resistance to beta-lactam antibiotics is beta-lactamase producing. The aim of this study was to compare the antibiotic resistance of urinary Escherichia coli (E. coli) isolates producing CTX-M and TEM type beta-lactamases, and to determine the strains with co-resistance to multiple antibiotics in Mashhad, Iran. Methods: E. coli b...

25 26 We examined E. faecalis strains clinically isolated from 100 UTI patients for their 27 susceptibility to levofloxacin (LVX) by measuring the minimal inhibitory concentration 28 (MIC), and investigated amino acid mutations by direct DNA sequencing which was 29 then correlated with LVX resistance. Next we studied risk factors for LVX resistance 30 such as age, sex, and previous fluoroquinol...