Resistance to broad-spectrum cephalosporins through the acquisition and expression of
Extended-Spectrum β-lactamase (ESBL) among Enterobacteriacea is increasing. The clinical
implications of ESBLs are extremely serious and sensitive diagnostic methods are urgently
needed to guide therapy, monitor resistance development and implement intervention
strategies. Conventionally, detection of expression of ESBLs was based on reduction of
ceftazidime of cefotaxime MICs by ≥ 3 two fold dilutions in the presence of clavulanic acid.
However, the use of the above method was limited to cover only some of the bacterial species,
including predominantly E. coli and Klebsiella spp., or tested strains which were all
transconjugants generated in vitro. ESBLs are now reported in a growing number of genera
other than E. coli or Klebsiella spp., and Serratia marcescens.
Carbapenems, including ertapenem, imipenem and meropenem, are the drugs of choice used for
severe ESBL-producing bacterial infections. Failure to detect ESBL at the presence of AmpC
β-lactamase might result in an important clinical concern because 4th generation
cephalosporins, which are stable to AmpC β-lactamase, is not a drug of choice for severe
infections caused by ESBLs-producing isolates. Fluoroquinolone-resistance in ESBL-producing
Enterobacteriacea is common. In this study, the investigators will use isolates of
Enterobacteriacea collected from different hospitals (isolates offered by the Taiwan
Surveillance of Antimicrobial Resistance [TSAR] program) to investigate the susceptibility of
ertapenem and five other antimicrobial agents against ESBLs-producing Enterobacteriacea.