Seção de Bacteriologia e Micologia, Instituto Evandro Chagas (IEC), Ananindeua, PA, Brazil.
Universidade Federal de São Paulo (UNIFESP), Laboratório ALERTA, Disciplina de Infectologia, Departamento de Medicina, Escola Paulista de Medicina (EPM), São Paulo, SP, Brazil.
J Antimicrob Chemother. 2023 Jun 1;78(6):1359-1366. doi: 10.1093/jac/dkad077.
To characterize a novel acquired MBL, BIM-1, in a Pseudomonas #2 (subgroup P. guariconensis) strain isolated from the Aurá river located in the Brazilian Amazon hydrographic basin.
WGS using an Illumina® MiSeq System was used to characterize the genome of Pseudomonas sp. IEC33019 strain. Southern blotting/hybridization assays were performed to confirm the location of the MBL-encoding gene, blaBIM-1 (Belém Imipenemase). Antimicrobial susceptibility testing, cloning, and biochemical and phenotypic characterization were performed to determine BIM-1 kinetics.
The IEC33019 strain showed high resistance rates to β-lactams, ciprofloxacin and aminoglycosides, being susceptible only to polymyxins and susceptible, increased exposure to aztreonam. WGS analysis revealed a novel acquired MBL-encoding gene, blaBIM-1, found as a gene cassette inserted into a class 1 integron (In1326) that also carried qnrVC1 and aadA11e. In1326 was located in a complex transposon, Tn7122, carried by a 52.7 kb conjugative plasmid (pIEC33019) with a toxin/antitoxin system (vapB/vapC). BIM-1 belongs to the molecular subgroup B1 and shares 70.2% and 64.9% similarity with SIM-1 and IMP-1, respectively. Kinetics analysis of BIM-1 showed hydrolytic activity against all β-lactams tested.
BIM-1 is a novel acquired MBL encoded by a gene carried by mobile genetic elements, which can be transferred to other Gram-negative bacilli (GNB). Because the IEC33019 strain was recovered from a river impacted by a populous metropolitan region with poor basic sanitation and served by limited potable freshwater, it would be important to establish the role of the BIM-1-producing GNB as nosocomial pathogens and/or as colonizers of the riverside population in this geographical region.
对一株从巴西亚马逊流域的奥拉河分离出的假单胞菌#2 （假单胞菌属瓜拉尼亚种）菌株中发现的新型获得性 MBL，BIM-1 进行表型特征鉴定。
采用 Illumina® MiSeq 系统进行全基因组测序，以鉴定假单胞菌 sp. IEC33019 菌株的基因组。通过 Southern blot/杂交实验来确认 MBL 编码基因 blaBIM-1（贝伦亚胺培南酶）的位置。进行药敏试验、克隆、生化和表型特征鉴定，以确定 BIM-1 的动力学。
IEC33019 株对β-内酰胺类、环丙沙星和氨基糖苷类药物的耐药率较高，仅对多黏菌素类药物敏感，且对氨曲南的敏感性增加。全基因组序列分析揭示了一种新型获得性 MBL 编码基因 blaBIM-1，该基因作为一个基因盒插入到一个 I 类整合子（In1326）中，该整合子还携带 qnrVC1 和 aadA11e。In1326 位于一个复杂的转座子 Tn7122 上，Tn7122 由一个 52.7 kb 的可接合质粒（pIEC33019）携带，该质粒上还带有一个毒素/抗毒素系统（vapB/vapC）。BIM-1 属于分子亚群 B1，与 SIM-1 和 IMP-1 的相似度分别为 70.2%和 64.9%。BIM-1 的动力学分析表明，它对所有测试的β-内酰胺类药物均具有水解活性。
BIM-1 是一种新型的获得性 MBL，由携带移动遗传元件的基因编码，该基因可转移至其他革兰氏阴性杆菌（GNB）。由于 IEC33019 菌株是从一条受到人口众多的大都市地区影响的河流中分离出来的，该地区的基本卫生条件较差，淡水供应有限，因此，有必要确定产生 BIM-1 的 GNB 是否作为医院获得性病原体以及/或作为该地区河流沿岸人群的定居者发挥作用。
