This paper investigates the biohydrogen production by two mesophilic strains, a strict anaerobe (Clostridium butyricum CWBI1009) and a facultative anaerobe (Citrobacter freundii CWBI952). They were cultured in pure and mixed cultures in serum bottles with five different carbon sources. The hydrogen yields of pure C. freundii cultures ranged from 0.09 molH2. molhexose -1 (with sucrose) to 0.24 m...

A carbapenem-resistant Citrobacter freundii strain WCHCF65 was recovered from hospital sewage and was characterized by genome sequencing and conjugation experiments. The strain carried nine genes encoding β-lactamases including two carbapenemase genes, blaNDM-1 and blaKPC-2. blaNDM-1 was carried on an IncX3 plasmid, which was identical to a plasmid found in a local Escherichia coli, suggesting ...

Ten quinolone-resistant mutants of Citrobacter freundii, which were selected in vitro with fluoroquinolones from two clinical isolates, were studied. The parent isolates were susceptible to quinolones in spite of showing a single substitution in the GyrB (His-417 --> Leu). No change was observed in the outer membrane proteins or in the lipopolysaccharide in any of the ten mutants studied with r...

Among 603 isolates of Enterobacteriaceae collected between June and November 2003 from three university hospitals within Korea, bla(CTX-M-3), bla(CTX-M-15), bla(CTX-M-14), and bla(CTX-M-9) were detected in 41 isolates of species from five different genera of Enterobacteriaceae, Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp., and Serratia marcescens.

The inactivation kinetics for inhibition by sulbactam (CP45,899) of Citrobacter freundii GN346 cephalosporinase were studied in detail and compared with those of type Ib penicillinase or TEM-2 beta-lactamase mediated by R plasmid RGN823. The rate constant for progressive inactivation of the cephalosporinase was significantly larger than that measured with the penicillinase. The number of sulbac...

In order to investigate biological properties of the dominant strain from the biological activated carbon (BAC) filter column, a novel, dominant iron-and-manganese removal strain, FM-2, was screened from BAC mature biological membrane. By phylogenetic analysis based on 16S rDNA sequence comparison, FM-2 was identified to be Citrobacter freundii. The experimental results indicated that Citrobact...