In vitro activity of flomoxef against extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in Korea.

To find an alternative regimen for the treatment of extended-spectrum β-lactamase (EBSL)-producing Enterobacteriaceae infections, we examined the in vitro activity of flomoxef against Escherichia coli and Klebsiella pneumoniae having CTX-M-1 group and/or CTX-M-9 group ESBLs. Boronic acid disk methods and polymerase chain reaction amplification were used to detect for ESBL, and AmpC β-lactamase and AmpC β-lactamase co-producers were excluded. Minimum inhibitory concentrations (MICs) were determined for flomoxef by broth microdilution. One hundred seventy-six isolates (E. coli, n = 93 and K. pneumoniae, n = 83) were analyzed for susceptibility test. A total of 94.3% (166/176) of isolates were susceptible to flomoxef (MIC50/MIC90 were 0.5/8 μg/mL); 98.9% of the ESBL-producing E. coli (MIC50/MIC90 were 1/4 μg/mL) and 89.2% of the ESBL-producing K. pneumoniae (MIC50/MIC90 were 0.5/16 μg/mL) were susceptible to flomoxef. Flomoxef has good in vitro activity against ESBL-producing E. coli and K. pneumoniae and could be considered as an alternative for infections caused by these organisms.

Jung Y ，Lee SS ，Song W ，Kim HS ，Uh Y ... -  《-》

In vitro activity of flomoxef and comparators against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis producing extended-spectrum β-lactamases in China.

The objective of this study was to better understand the in vitro activity of flomoxef against clinical extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. A total of 401 ESBL-producing isolates, including 196 Escherichia coli, 124 Klebsiella pneumoniae and 81 Proteus mirabilis, were collected consecutively from 21 hospitals in China in 2013. Minimum inhibitory concentrations (MICs) were determined by broth microdilution methods. Phenotypic identification of ESBL production was detected as recommended by the Clinical and Laboratory Standards Institute (CLSI). ESBL genes were detected by PCR and sequencing. Flomoxef, doripenem, meropenem, ertapenem, cefmetazole and piperacillin/tazobactam exhibited good activity against ESBL-producing isolates, with susceptibility rates >90%. Tigecycline showed good activity against E. coli and K. pneumoniae (100% and 97.6%, respectively). Cefotaxime and cefepime showed very low activities against ESBL-producing isolates, with susceptibility rates of 0-0.8% and 1.0-13.6%, respectively. blaCTX-M were the major ESBL genes, with occurrence in 99.5% of E. coli, 91.1% of K. pneumoniae and 97.5% of P. mirabilis. blaCTX-M-14 was the predominant ESBL gene, detected in 46.9% (188/401) of the isolates, followed by blaCTX-M-15 (21.4%), blaCTX-M-55 (17.2%), blaCTX-M-65 (12.7%) and blaCTX-M-3 (6.7%). Flomoxef exhibited excellent activity against the different CTX-M-type ESBL-producing isolates, with MIC50 and MIC90 values of 0.064-0.125μg/mL and 0.25-0.5μg/mL, respectively. Against the isolates solely producing CTX-M-14, -15, -55, -3 or -65, flomoxef showed susceptibility rates of 98.6%, 98.0%, 98.1%, 100.0% and 97.4%, respectively. In conclusion, flomoxef showed good activity against ESBL-producing Enterobacteriaceae and may be a choice to treat infections caused by these isolates in China.

Yang Q ，Zhang H ，Cheng J ，Xu Z ，Xu Y ，Cao B ，Kong H ，Ni Y ，Yu Y ，Sun Z ，Hu B ，Huang W ，Wang Y ，Wu A ，Feng X ，Liao K ，Shen D ，Hu Z ，Chu Y ，Lu J ，Su J ，Gui B ，Duan Q ，Zhang S ，Shao H ... -  《-》

In Vitro Activity of Cefotetan against ESBL-Producing Escherichia coli and Klebsiella pneumoniae Bloodstream Isolates from the MERINO Trial.

Stewart AG ，Cottrell K ，Henderson A ，Vemuri K ，Bauer MJ ，Paterson DL ，Harris PNA ... -  《Microbiology Spectrum》

Can results obtained with commercially available MicroScan microdilution panels serve as an indicator of beta-lactamase production among escherichia coli and Klebsiella isolates with hidden resistance to expanded-spectrum cephalosporins and aztreonam?

Moland ES ，Sanders CC ，Thomson KS 《-》

Molecular characteristics of extended spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae and the prevalence of qnr in Extended spectrum beta-lactamase isolates in a tertiary care hospital in Korea.

Kim MH ，Lee HJ ，Park KS ，Suh JT ... -  《-》