Rodríguez María-Cruz, Ruiz del Castillo Belén, Rodríguez-Mirones Cristina, Romo María, Monteagudo Idoia, Martínez-Martínez Luis
Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain.
Enferm Infecc Microbiol Clin. 2010 Feb;28(2):99-103. doi: 10.1016/j.eimc.2009.01.013. Epub 2009 May 1.
Pseudomonas aeruginosa strains producing metallo-beta-lactamases (MbetaL) are uncommon in Spain. This study describes the characterization of 9 new clonally related multiresistant P. aeruginosa isolates possessing the bla(VIM-2) gene in Cantabria (Northern Spain).
P. aeruginosa clinical strains (1 per patient) were isolated in the Microbiology Service of Marqués de Valdecilla University Hospital between January 2004 and December 2006. Identification and preliminary susceptibility studies were performed with the MicroScan WalkAway system (Dade Behring, Sacramento, CA) and results were verified by a microdilution reference method.
MICs of imipenem and meropenem for the 9 isolates ranged from 32 to 128 and 16 to 64 microg/mL, respectively. Nine isolates had a single Rep-PCR pattern and were intermediate or resistant to ceftazidime, cefepime, gentamicin, tobramycin, amikacin and ciprofloxacin. Eight of the 9 isolates were susceptible to aztreonam. Hydrolysis activity of imipenem in MbetaL-positive isolates ranged from 162+/-18 to 235+/-28 pmol/min/microg protein and was abolished in the presence of 5 mM EDTA. All isolates possessed an integron with genes aac(6')32, bla(VIM-2) and a putative transposase-encoding gene, flanked by the conserved 5'CS and 3'CS regions.
In the clinical isolates studied, the presence of MbetaL VIM-2 sufficed to explain their resistance to carbapenems.
产金属β-内酰胺酶（MβL）的铜绿假单胞菌菌株在西班牙并不常见。本研究描述了在西班牙北部坎塔布里亚发现的9株新的具有克隆相关性的多重耐药铜绿假单胞菌分离株的特征，这些分离株携带bla(VIM-2)基因。
2004年1月至2006年12月期间，从巴尔德西利亚侯爵大学医院微生物科分离出铜绿假单胞菌临床菌株（每位患者1株）。使用MicroScan WalkAway系统（美国加利福尼亚州萨克拉门托市达德拜林公司）进行鉴定和初步药敏研究，结果通过微量稀释参考方法进行验证。
9株分离株对亚胺培南和美罗培南的最低抑菌浓度（MIC）分别为32至128 μg/mL和16至64 μg/mL。9株分离株具有单一的重复聚合酶链反应（Rep-PCR）模式，对头孢他啶、头孢吡肟、庆大霉素、妥布霉素、阿米卡星和环丙沙星呈中介或耐药。9株分离株中有8株对氨曲南敏感。MβL阳性分离株中亚胺培南的水解活性为162±18至235±28 pmol/分钟/μg蛋白，在5 mM乙二胺四乙酸（EDTA）存在时被消除。所有分离株均含有一个整合子，其基因包括aac(6')32、bla(VIM-2)和一个假定的转座酶编码基因，两侧为保守的5'保守序列（5'CS）和3'保守序列（3'CS）区域。
在所研究的临床分离株中，MβL VIM-2的存在足以解释它们对碳青霉烯类药物的耐药性。
