title: Risk factors and clinical features of infections caused by plasmid-mediated AmpC beta-lactamase-producing Enterobacteriaceae.
abstract: A case-control study was performed with the objective of analysing risk factors and clinical features of infections caused by plasmid-mediated AmpC beta-lactamase (plasmid AmpC)-producing Enterobacteriaceae. All patients infected with plasmid AmpC-producing Enterobacteriaceae in two tertiary care hospitals from December 2006 to August 2007 were included. Plasmid AmpC enzymes were characterised by isoelectric focusing, enzyme inhibition assay and enzyme-specific polymerase chain reaction. A total of 30 patients (20 with Klebsiella pneumoniae and 10 with Escherichia coli) were recruited prospectively. CMY-2 and DHA-1 were the most common plasmid AmpC in E. coli and K. pneumoniae, respectively. An independent risk factor for infection with plasmid AmpC-producing Enterobacteriaceae was the use of an oxyimino-cephalosporin within 1 month of plasmid AmpC infection [adjusted odds ratio (aOR), 10.8, 95% confidence interval (CI), 1.6-75.4; P=0.016], with the use of a urinary catheter showing borderline significance (aOR, 6, 95% CI 0.93-38.4; P=0.06). An independent risk factor for treatment failure at 72 h was infection due to plasmid AmpC-producing Enterobacteriaceae (aOR, 9.78, 95% CI 1.34-71.17; P=0.02). These results suggest that infections caused by plasmid AmpC-producing isolates significantly increase treatment failure at 72 h and that prior use of an oxyimino-cephalosporin is a risk factor for infections caused by plasmid AmpC-producing Enterobacteriaceae.
authors.affiliation: Department of Internal Medicine, Gachon University, Gil Medical Center, 1198 Guwol-dong, Namdong-gu, Incheon 405-760, South Korea.
authors.forename: Yoon Soo
authors.initials: YS
authors.lastname: Park
authors.forename: Sunmi
authors.initials: S
authors.lastname: Yoo
authors.forename: Mi-Ran
authors.initials: MR
authors.lastname: Seo
authors.forename: Jin Yong
authors.initials: JY
authors.lastname: Kim
authors.forename: Yong Kyun
authors.initials: YK
authors.lastname: Cho
authors.forename: Hyunjoo
authors.initials: H
authors.lastname: Pai
mesh_terms: D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D015373:Bacterial Typing Techniques; D016022:Case-Control Studies; D016000:Cluster Analysis; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology / Q000503:physiopathology; D004269:DNA, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology / Q000503:physiopathology*; D005260:Female; D005838:Genotype; D006801:Humans; D007525:Isoelectric Focusing; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D010957:Plasmids; D012307:Risk Factors; D014546:Urinary Catheterization / Q000009:adverse effects; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C048795:AmpC beta-lactamases; D001618:beta-Lactamases