Gill Christian M, Asempa Tomefa E, Nicolau David P
Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT 06102, USA.
Division of Infectious Diseases, Hartford Hospital, Hartford, CT 06102, USA.
Antibiotics (Basel). 2020 Oct 27;9(11):738. doi: 10.3390/antibiotics9110738.
A minimum inhibitory concentration (MIC) derived algorithm, predictive of carbapenemase production, was developed using a challenge set ( = 92) of (PA), including carbapenemase-producing (CP), cephalosporinase and/or efflux/porin mutation, and wild-type isolates. Broth microdilution MICs to clinically relevant anti-pseudomonal agents were utilized. The algorithm was applied to 1209 clinical PA isolates from a US surveillance program. Confirmatory genotypic (Xpert Carba-R assay) and phenotypic (mCIM/eCIM) testing for carbapenemases was conducted on algorithm-derived isolates. With the algorithm, carbapenem resistance alone resulted in poor specificity to identify CP-PA (54%) within the challenge set of isolates. Inclusion of cefepime, ceftazidime, and piperacillin/tazobactam non-susceptibility resulted in a specificity of 66%. Ceftolozane/tazobactam resistance further improved specificity (89%). Of the 1209 isolates, 116 met criteria (carbapenem-resistant and non-susceptibility to cefepime, ceftazidime, and piperacillin/tazobactam) for confirmatory testing. Carba-R and mCIM/eCIM identified five (all -positive) and seven carbapenemase-producing isolates, respectively. This MIC algorithm combined with genotypic/phenotypic carbapenemase testing is a pragmatic and streamlined approach to identify CP-PA.
利用一组包含92株铜绿假单胞菌（PA）的挑战集开发了一种预测碳青霉烯酶产生的最低抑菌浓度（MIC）衍生算法，其中包括产碳青霉烯酶（CP）、头孢菌素酶和/或外排/孔蛋白突变菌株以及野生型菌株。采用肉汤微量稀释法测定了对临床相关抗假单胞菌药物的MIC。该算法应用于美国一项监测项目中的1209株临床PA分离株。对算法得出的分离株进行了碳青霉烯酶的确认性基因检测（Xpert Carba - R检测）和表型检测（mCIM/eCIM）。在分离株挑战集中，仅碳青霉烯耐药对鉴定产碳青霉烯酶的PA（CP - PA）特异性较差（54%）。纳入头孢吡肟、头孢他啶和哌拉西林/他唑巴坦不敏感结果后，特异性为66%。头孢洛扎/他唑巴坦耐药进一步提高了特异性（89%）。在1209株分离株中，有116株符合确认性检测标准（碳青霉烯耐药且对头孢吡肟、头孢他啶和哌拉西林/他唑巴坦不敏感）。Carba - R检测和mCIM/eCIM分别鉴定出5株（均为阳性）和7株产碳青霉烯酶的分离株。这种MIC算法结合基因/表型碳青霉烯酶检测是一种实用且简化的鉴定CP - PA的方法。
