Servicio de Microbiología, IIS Aragón, Hospital Clínico Universitario Lozano Blesa, Zaragoza, Spain.
Sección de Microbiología, Hospital Universitario Arnau de Vilanova, Lérida, Spain.
Eur J Clin Microbiol Infect Dis. 2018 Oct;37(10):1847-1856. doi: 10.1007/s10096-018-3318-3. Epub 2018 Jul 6.
To analyse the antimicrobial phenotype, carbapenem mechanisms, integrons, virulence factors and molecular typing of 164 Pseudomonas aeruginosa isolates recovered from lower tract respiratory samples in a Spanish hospital (1 year) as well as the patients' clinical data. Susceptibility testing to 12 antipseudomonal agents was determined by microdilution and metallo-beta-lactamase (MBL) phenotype by double disc method. The oprD gene was studied by PCR, sequencing and comparison with P. aeruginosa PAO1 sequence. Detection and characterisation of MBLs, class 1, 2 and 3 integrons, and virulence genes were studied by PCR and sequencing. The prevalence of carbapenem-resistant P. aeruginosa (CRPA) was 26.8%. MBL phenotype was detected in 52.3% CRPA, and all of them were disseminated throughout the intensive care unit. Most of the MBL-carrying patients presented respiratory disease, mechanical ventilation, tracheostomy, bacteraemia, ≥ 30 hospitalisation days and previous treatment with carbapenems and/or ≥ 3 different antimicrobial families. The bla gene was the unique MBL encoding gene and was detected inside class 1 integrons. The class 1 integrons detected in 39 strains (23.8%) were associated with aminoglycosides (aadB, aadA1, aadA6, aacA4, aac(3)-I) and carbapenems resistance genes (bla). The aac(3)-I + aadA1 and bla arrangements were the most prevalent ones. Thirty-one different PFGE patterns and 4 STs (ST175, ST235, ST253, ST973) were detected among the 39 intI1-positive isolates, being ST235 the most frequent. CRPA showed a great variety of alterations in oprD gene. The exoU/exoS genotype was detected in 82.6% of bla-producing strains (ST235) and the exoU/exoS in the remaining 17.4% (ST973).
分析了 164 株铜绿假单胞菌分离株的抗菌表型、碳青霉烯机制、整合子、毒力因子和分子分型，这些分离株是从西班牙一家医院的下呼吸道样本（1 年）中获得的，以及患者的临床数据。采用微量稀释法测定 12 种抗假单胞菌药物的药敏试验，采用双碟法测定金属β-内酰胺酶（MBL）表型。通过 PCR、测序和与铜绿假单胞菌 PAO1 序列比较研究 oprD 基因。采用 PCR 和测序研究 MBLs、1 类、2 类和 3 类整合子和毒力基因的检测和特征。耐碳青霉烯铜绿假单胞菌（CRPA）的患病率为 26.8%。在 52.3%的 CRPA 中检测到 MBL 表型，所有这些都在重症监护病房中传播。携带 MBL 的大多数患者患有呼吸道疾病、机械通气、气管切开术、菌血症、≥30 天住院时间和以前使用碳青霉烯类药物和/或≥3 种不同的抗菌药物治疗。bla 基因是唯一的 MBL 编码基因，检测到在 1 类整合子内。在 39 株（23.8%）检测到的 1 类整合子与氨基糖苷类（aadB、aadA1、aadA6、aacA4、aac(3)-I）和碳青霉烯类耐药基因（bla）有关。aac(3)-I+aadA1 和 bla 排列是最常见的。在 39 株 intI1 阳性分离株中检测到 31 种不同的 PFGE 模式和 4 种 ST（ST175、ST235、ST253、ST973），其中 ST235 最常见。CRPA 对 oprD 基因有很大的改变。在产生 bla 的菌株（ST235）中检测到 82.6%的 exoU/exoS 基因型，在其余 17.4%（ST973）中检测到 exoU/exoS。
