UNASSIGNED: We collected 129 MABC isolates from patients with lower respiratory tract infections and categorized them into three subspecies. The minimum inhibitory concentrations (MICs) of 15 antimicrobials for the MABC isolates were determined using commercial Sensititre RAPMYCOI MIC plates and the broth microdilution method, as recommended in the CLSI (M24-A2). In addition, the MICs of imipenem, alone and with ceftazidime and/or avibactam, were assessed in vitro for all isolates. The erm(41) and rrl genes were also sequenced.
UNASSIGNED: The MABC isolates exhibited >80% resistance to 11 of the 15 antimicrobials. Regarding the remaining four antimicrobials, the isolates were least resistant to tigecycline (12.4%) and amikacin (3.9%), and only partially resistant to two cefoxitin (39.5%) and imipenem (40.3%). Compared with M. massiliense isolates, M. abscessus and M. bolletii isolates were more resistant to amikacin and imipenem, whereas M. abscessus was significantly less resistant to tigecycline relative to M. massiliense and M. bolletii isolates. The clarithromycin inducible resistance rate was 68.4% and 74.3% among M. bolletii and M. abscessus isolates. Furthermore, 88.7% of the M. abscessus isolates carried a T at position 28 of erm(41), which is associated with inducible clarithromycin resistance. In addition, compared to imipenem with avibactam only, the MIC50 and MIC90values of imipenem after adding ceftazidime plus avibactam were decreased fourfold.
UNASSIGNED: The antimicrobial resistance rates and the characteristics of the erm(41) gene associated with inducible clarithromycin resistance were different among the three MABC subspecies. There was also synergy between imipenem and 100μg/mL ceftazidime against MABC isolates.
■我们从下呼吸道感染患者中收集了129个MABC分离株,并将其分为三个亚种。使用商业的SensititreRAPMYCOIMIC板和肉汤微量稀释法测定了MABC分离株的15种抗微生物剂的最低抑制浓度(MIC),按照CLSI(M24-A2)的建议。此外,亚胺培南的中等收入国家,单独使用头孢他啶和/或阿维巴坦,对所有分离株进行了体外评估。还对erm(41)和rrl基因进行了测序。
■MABC分离株对15种抗微生物剂中的11种表现出>80%的抗性。关于其余四种抗菌药物,分离株对替加环素(12.4%)和阿米卡星(3.9%)的耐药率最低,而对两种头孢西丁(39.5%)和亚胺培南(40.3%)仅部分耐药。与M.massiliense分离株相比,脓肿分枝杆菌和博勒蒂分枝杆菌对阿米卡星和亚胺培南的耐药性更强,而脓肿分枝杆菌对替加环素的耐药性明显低于马氏分枝杆菌和博利提分枝杆菌。克拉霉素诱导耐药率分别为68.4%和74.3%。此外,88.7%的脓肿分枝杆菌分离株在erm(41)的28位携带T,这与诱导型克拉霉素耐药有关。此外,与只有阿维巴坦的亚胺培南相比,添加头孢他啶和阿维巴坦后,亚胺培南的MIC50和MIC90值降低了四倍。
■三个MABC亚种的抗菌药物耐药率和与诱导型克拉霉素耐药相关的erm(41)基因的特征不同。亚胺培南和100μg/mL头孢他啶对MABC分离株也有协同作用。