In vitro activities of doripenem and other carbapenems against clinically important bacteria isolated in intensive care units: nationwide data from the SMART Programme

Abstract

This nationwide surveillance of clinically important bacteria from the intensive care units (ICUs) of major teaching hospitals throughout Taiwan investigated the susceptibilities to doripenem and other comparator carbapenems from September through November 2005. Minimum inhibitory concentrations (MICs) were determined for 1,311 clinical isolates using the broth microdilution method according to Clinical and Laboratory Standards Institute (CLSI) 2005 guidelines. Doripenem showed similar (within four-fold difference of MICs) in vitro activity to meropenem for Enterobacteriaceae and probably comparable activity to meropenem against important nosocomial non-fermentative Gram-negative bacilli (NFGNBs), including Pseudomonas aeruginosa, Acinetobacter baumannii and Burkholderia cepacia. Among the four carbapenems analysed, doripenem and meropenem exhibited better in vitro activity than imipenem or ertapenem against extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli isolates. However, the meropenem MIC(90) against ESBL-producing K. pneumoniae isolates was 2 microg/ml. Besides, doripenem with the MIC(90) of 0.5 microg/ml to Streptococcus pneumoniae possibly suggested its potential therapeutic effect regarding community-acquired pneumonia. Because of the heavy resistance burden in Taiwan, closely monitoring the evolutionary trend of carbapenem susceptibilities against clinically important pathogens is crucial in the future.

Activities of doripenem against nosocomial bacteremic drug-resistant Gram-negative bacteria in a medical center in Taiwan

“…8,21e25 Similar trends were also seen in other tested antibiotics. 21e29 Compared to the study conducted by Jean et al, the only study investigated the susceptibilities to doripenem in Taiwan before our study, 15 we found that the MIC 90 s of doripenem and meropenem in P. aeruginosa and A. baumannii were both increased (6 mg/mL and 6 mg/mL vs. 1 mg/ mL and 4 mg/mL, >32 mg/mL and >32 mg/mL vs. 16 mg/mL and 16 mg/mL, respectively). We could not compare the differences in susceptibility rates, because Jean et al did not report these rates in their study.…”

“…Before our investigation, there has only been one study in Taiwan, which reported the susceptibility and in vitro activity of doripenem against clinically important bacteria. 15 Since the bacterial isolates used in that study were collected in 2005, 15 there might have been significant changes in drug resistance during this time period. Therefore, we conducted the present study using more contemporary clinical isolates.…”

“…13 However, the clinical experience of using doripenem to treat infections caused by multidrug-resistant pathogens and data on its in vitro activities against multidrug-resistant pathogens remained limited in Taiwan. 15 The study was designed to compare the in vitro activities of doripenem and other antimicrobial agents including imipenem and meropenem, against drug-resistant Gramnegative pathogens isolated in a medical center in Taiwan.…”

In vitro susceptibilities of clinical isolates of ertapenem-non-susceptible Enterobacteriaceae to nemonoxacin, tigecycline, fosfomycin and other antimicrobial agents

“…Vancomycin MICs have been shown to vary depending on the method of measurement. Conflicting data have been published on the ability of commercial automated susceptibility testing methods in comparison with that of the Etest to provide accurate vancomycin MIC estimations for S. aureus [2][3][4]. In a recent study, Swenson et al [4] found that the BD Phoenix TM system (PMIC-102 and -104 cards with a vancomycin range of 0.5-16 g/mL) from Becton Dickinson (Sparks, MD) tended to categorise susceptible strains as vancomycin-intermediate S. aureus (VISA) and overall yielded higher MIC values compared with those obtained by the standard Etest.…”

“…The nationwide Study for Monitoring Antimicrobial Resistance Trends (SMART) programme reported in 2005 that ertapenem was highly active against Enterobacteriaceae isolates [2]. Recently, however, ertapenem-resistant Enterobacteriaceae isolates have been reported in the UK [3] and have also been observed in Taiwan.…”