In Vitro Susceptibility of piperacillin/tazobactam Against extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae / 감염과화학요법

Minimal inhibitory concentrations (MIC) of piperacillin/tazobactam were determined on 20 clinical isolates of extended-spectrum beta-lactamase (ESBL)-producing E. coli and 30 isolates of ESBL- producing Klebsiella pneumoniae. MIC50 and MIC90 for ESBL-producing E. coli were 8/4 microg/ml and 256/4 microg/mL, respectively. MIC50 and MIC90 for ESBL-producing K. pneumoniae were 8/4 microg/mL and > 512/4 microg/mL, respectively. The susceptibilities of ESBL-producing E. coli and K. pneumoniae to piperacillin/tazobactam were 80% and 60%, respectively. Of 20 ESBL-producing E. coli strains, 11 (55%) were TEM-and CTX-M-positive, and SHV-negative. Of 30 ESBL-producing K. pneumoniae strains, ten (33%) were PCR positive for SHV and negative for TEM and CTX-M.

In Vitro Susceptibility of piperacillin/tazobactam Against extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae / 감염과화학요법

Minimal inhibitory concentrations (MIC) of piperacillin/tazobactam were determined on 20 clinical isolates of extended-spectrum beta-lactamase (ESBL)-producing E. coli and 30 isolates of ESBL- producing Klebsiella pneumoniae. MIC50 and MIC90 for ESBL-producing E. coli were 8/4 microg/ml and 256/4 microg/mL, respectively. MIC50 and MIC90 for ESBL-producing K. pneumoniae were 8/4 microg/mL and > 512/4 microg/mL, respectively. The susceptibilities of ESBL-producing E. coli and K. pneumoniae to piperacillin/tazobactam were 80% and 60%, respectively. Of 20 ESBL-producing E. coli strains, 11 (55%) were TEM-and CTX-M-positive, and SHV-negative. Of 30 ESBL-producing K. pneumoniae strains, ten (33%) were PCR positive for SHV and negative for TEM and CTX-M.

In vitro activity of ceftobiprole against hospital-acquired bacteria commonly causing infections in hospitalized patients at Siriraj Hospital.

Objective: To determine the in vitro activity of ceftobiprole against resistant bacteria commonly causing infections in hospitalized patients at Siriraj Hospital. Methods: The studied organisms were MRSA (32 isolates), Enterococcus sp. (30 isolates), ESBL-producing E.coli (20 isolates), ESBL-producing K.pneumoniae (20 isolates), MDR P.aeruginosa (30 isolates) and MDR A.baumannii (30 isolates). The susceptibility of ceftobiprole was determined by the disk diffusion test for all 162 isolates and the MIC was determined by the E-test method for 5 isolates of each organism. Results: All isolates of MRSA and 77% of Enterococcus sp. isolates were susceptible to ceftobiprole. All isolates of ESBL-producing E.coli and MDR A.baumannii were not susceptible to ceftobiprole. Only 10% to 20% of ESBL-producing K.pneumoniae and P.aeruginosa were susceptible to ceftobiprole. The MICs of ceftobiprole against all tested organisms were correlated with the inhibition zone diameters. Conclusion: Ceftobiprole is very active against MRSA and is moderately active against Enterococcus sp. Ceftobiprole is considered inactive or less active against ESBL-producing gram negatives, MDR P.aeruginosa and MDR A.baumannii.