Marchetti Vittoria Mattioni, Bitar Ibrahim, Sarti Mario, Fogato Elena, Scaltriti Erika, Bracchi Chiara, Hrabak Jaroslav, Pongolini Stefano, Migliavacca Roberta
Department of Microbiology, Faculty of Medicine and University Hospital in Pilsen, Charles University, 306 05 Pilsen, Czech Republic.
Biomedical Center, Faculty of Medicine, Charles University, 323 00 Pilsen, Czech Republic.
Diagnostics (Basel). 2021 Jan 6;11(1):79. doi: 10.3390/diagnostics11010079.
the co-production of carbapenemases and -genes represents a worrisome event in the treatment of infections. The aim of the study was to characterize the genomic features of two clinical complex (ECC) isolates, co-producing VIM and MCR enzymes, in Italy.
species identification and antibiotic susceptibility profiling were performed using MALDI-TOF and broth microdilution methods, respectively. Transferability of the and - type genes was verified through conjugation experiment. Extracted DNA was sequenced using long reads sequencing technology on the Sequel I platform (PacBio).
the first isolate showed clinical resistance against ertapenem yet was colistin susceptible (EUCAST 2020 breakpoints). The gene was harbored on a conjugative IncHI2 plasmid, while the determinant was harbored on a conjugative IncN plasmid. The second isolate, resistant to both carbapenems and colistin, harbored: gene and its two component regulatory genes for increased expression on the chromosome, on non-conjugative (yet co-transferable) ColE plasmid, and on a non-conjugative IncA plasmid.
to our knowledge, this is the first report of co-production of VIM and MCR in ECC isolates in Italy.
碳青霉烯酶及其基因的共同产生是感染治疗中一个令人担忧的事件。本研究的目的是对意大利两株临床复合菌（ECC）分离株进行基因组特征分析，这两株菌共同产生VIM和MCR酶。
分别使用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF）和肉汤微量稀释法进行菌种鉴定和抗生素敏感性分析。通过接合实验验证碳青霉烯酶和黏菌素抗性基因的可转移性。提取的DNA在Sequel I平台（PacBio）上使用长读长测序技术进行测序。
第一株分离株对厄他培南表现出临床耐药性，但对黏菌素敏感（根据2020年欧洲抗菌药物敏感性试验委员会（EUCAST）标准）。VIM基因位于一个可接合的IncHI2质粒上，而mcr决定簇位于一个可接合的IncN质粒上。第二株分离株对碳青霉烯类和黏菌素均耐药，其染色体上携带mcr基因及其两个用于增加表达的组成型调节基因，mcr-1位于非接合型（但可共同转移）的ColE质粒上，mcr-3位于一个非接合型的IncA质粒上。
据我们所知，这是意大利ECC分离株中VIM和MCR共同产生的首次报道。
