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.