The detection of synergy between meropenem and polymyxin B against meropenem-resistant Acinetobacter baumannii using Etest® and time-kill assay

Pankey, George A.; Ashcraft, Deborah

doi:10.1016/j.diagmicrobio.2008.11.002

Cited by 44 publications

(29 citation statements)

References 14 publications

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“…A promising finding was that antagonism was not detected with these combinations. Since carbapenems are frequently administered to treat MDR-AB infections, most in vitro studies on antimicrobial combinations are performed with a carbapenem and a polymyxin in combination (10,(21)(22)(23). However, there is limited data regarding the efficacy of PB with AS or CS, which are usually suggested agents in combination therapies (17).…”

Section: Discussionmentioning

confidence: 99%

Determination of In Vitro Activities of Polymyxin B and Rifampin in Combination with Ampicillin/Sulbactam or Cefoperazone/Sulbactam against Multidrug-Resistant <i>Acinetobacter baumannii</i> by the E-test and Checkerboard Methods

et al. 2013

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SUMMARY:The aim of this study was to investigate the in vitro activities of polymyxin B (PB) and rifampin (RIF) in combination with ampicillin/sulbactam (AS) or cefoperazone/sulbactam (CS) against 20 multidrug-resistant Acinetobacter baumannii (MDR-AB) isolates by the checkerboard and E-test methods. Fractional inhibitory concentration index (FICI) values were defined as synergy, FICI Ã 0.5; additivity, 0.5 º FICI Ã 1.0, indifference, 1.0 º FICI º 4.0; and antagonism, FICI AE 4. Synergistic interaction was detected only for the RIF ＋ AS and RIF ＋ CS combinations. While the most frequently detected interaction type for PB ＋ AS or PB ＋ CS combinations was indifference, some showed antagonistic interactions. The detection rate of synergy was significantly higher by the checkerboard than by the E-test method, and the detection rate of indifference was significantly higher by the E-test than by the checkerboard method for RIF ＋ AS combination ( P Ã 0.0001). In addition, no statistically significant difference was detected between the checkerboard and E-test methods for the detection rates of interaction types for any of the other combinations ( P À 0.05), except for PB ＋ CS combination for the detection of additivity ( P ＝ 0.018). Owing to the high percentage of synergistic interactions between RIF and AS, we considered this combination as an effective therapeutic option for MDR-AB infections.

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Section: Discussionmentioning

confidence: 99%

Determination of In Vitro Activities of Polymyxin B and Rifampin in Combination with Ampicillin/Sulbactam or Cefoperazone/Sulbactam against Multidrug-Resistant <i>Acinetobacter baumannii</i> by the E-test and Checkerboard Methods

et al. 2013

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“…Additivity/indifference was defined as <2-log 10 CFU/ml change in the combination compared with the viable count in the presence of the more active of the two antibiotics used (Choi et al, 2004), or 5. Synergy was defined as a ≥2-log 10 reduction in CFU for a combination compared to the most active single agent (Pankey and Ashcraft, 2009), or 6. Bactericidal activity was defined as ≥3-log 10 CFU/ml reduction in the colony count relative to the initial inoculums.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

A meta-analysis of in vitro antibiotic synergy against Acinetobacter baumannii

March

Bratos

2015

Journal of Microbiological Methods

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“…Colistin plus minocycline, tigecycline plus amikacin, carbapenems (imipenem and meropenem) plus polymyxins (polymyxin B and colistin), imipenem plus tigecycline, colistin plus vancomycin, colistin plus teicoplanin, and rifampicin plus sulbactam have also been reported to have synergistic effects (Hornsey & Wareham, 2011;Moland et al, 2008;Pachó nIbáñez et al, 2006;Gordon et al, 2010;Pankey & Ashcraft, 2009;Sopirala et al, 2010;Tan et al, 2007). In addition, imipenem plus sulbactam and colistin plus rifampicin combinations were effective in vitro against carbapenemresistant A. baumannii isolates (Song et al, 2007).…”

Section: K R Peck and Othersmentioning

confidence: 99%

In vitro time-kill studies of antimicrobial agents against blood isolates of imipenem-resistant Acinetobacter baumannii, including colistin- or tigecycline-resistant isolates

Peck

Kim

Choi

et al. 2012

Journal of Medical Microbiology

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The emergence of colistin or tigecycline resistance as well as imipenem resistance in Acinetobacter baumannii poses a great therapeutic challenge. The bactericidal and synergistic effects of several combinations of antimicrobial agents against imipenem-, colistin-or tigecyclineresistant A. baumannii isolates were investigated by in vitro time-kill experiments. Six imipenemresistant A. baumannii blood isolates were examined in this study, including colistin-and tigecycline-susceptible, colistin-resistant but tigecycline-susceptible, and colistin-susceptible but tigecycline-resistant isolates. Time-kill studies were performed using five antimicrobial agents singly or in combinations (imipenem plus colistin, imipenem plus ampicillin-sulbactam, colistin plus rifampicin, colistin plus tigecycline, and tigecycline plus rifampicin) at concentrations of 0.5¾ and 1¾ their MICs. Only imipenem was consistently effective as a single agent against all six A. baumannii isolates. Although the effectiveness of combinations of 0.5¾ MIC antimicrobial agents was inconsistent, combination regimens using 1¾ MIC of the antimicrobial agents displayed excellent bactericidal activities against all six A. baumannii isolates. Among the combinations of 0.5¾ MIC antimicrobial agents, the combination of colistin and tigecycline showed synergistic or bactericidal effects against four of the isolates. This in vitro time-kill analysis suggests that antimicrobial combinations are effective for killing imipenem-resistant A. baumannii isolates, even if they are simultaneously resistant to either colistin or tigecycline. However, the finding that the combinations of 0.5¾ MIC antimicrobial agents were effective on only some isolates may warrant further investigation of the doses of combination agents needed to kill resistant A. baumannii.

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The detection of synergy between meropenem and polymyxin B against meropenem-resistant Acinetobacter baumannii using Etest® and time-kill assay

Cited by 44 publications

References 14 publications

Determination of In Vitro Activities of Polymyxin B and Rifampin in Combination with Ampicillin/Sulbactam or Cefoperazone/Sulbactam against Multidrug-Resistant <i>Acinetobacter baumannii</i> by the E-test and Checkerboard Methods

Determination of In Vitro Activities of Polymyxin B and Rifampin in Combination with Ampicillin/Sulbactam or Cefoperazone/Sulbactam against Multidrug-Resistant <i>Acinetobacter baumannii</i> by the E-test and Checkerboard Methods

A meta-analysis of in vitro antibiotic synergy against Acinetobacter baumannii

In vitro time-kill studies of antimicrobial agents against blood isolates of imipenem-resistant Acinetobacter baumannii, including colistin- or tigecycline-resistant isolates

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