Gaiarsa Stefano, Merla Cristina, Corbella Marta, Mariani Bianca, Zatelli Michela, Sciabica Irene, Castelli Michele, Piazza Aurora, Zecca Marco, Sassera Davide, Cambieri Patrizia
U.O.C. Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
Scuola di Specializzazione in Microbiologia e Virologia, Università degli Studi di Pavia, Pavia, Italy.
Microb Drug Resist. 2022 Apr;28(4):408-412. doi: 10.1089/mdr.2021.0267. Epub 2022 Mar 28.
spp. are bacteria that are often detected in the environment and as symbionts of arthropods. They sporadically cause infections in humans and recently extended spectrum beta-lactamases (ESBL)- and carbapenemase-producing strains have started to emerge. In this study, we report the isolation and the complete genome sequence of a strain of encoding the colistin-resistance gene . The strain was isolated from a preterm newborn in a neonatal pathology ward. On clinical examination, his vital signs were normal and blood culture was negative. Rectal swab screening for ESBL-producing allowed to isolate the bacterium, and a complete genome was obtained using both short and long read sequencing. The gene was found to be encoded on a IncHI2 superplasmid, which confers resistance to six classes of antibiotics, including beta lactams (ESBL). Despite the presence of , the isolate retains susceptibility to colistin, which could be explained by the absence of compatible regulatory genes ( from the genome. The presence of the resistance gene is undetectable with the routine clinical procedures, that is, phenotypic tests. This suggests that a silent spread might be ongoing in the ward. To our knowledge, this is the first description of an MDR and of a spp. encoding any mobile colistin resistance gene.
某些菌种是常在环境中以及作为节肢动物的共生体被检测到的细菌。它们偶尔会引起人类感染，并且最近产超广谱β-内酰胺酶（ESBL）和碳青霉烯酶的菌株已开始出现。在本研究中，我们报告了一株编码黏菌素抗性基因的菌株的分离及完整基因组序列。该菌株是从新生儿病理病房的一名早产新生儿中分离出来的。临床检查时，其生命体征正常且血培养阴性。对产ESBL的该菌种进行直肠拭子筛查得以分离出该细菌，并使用短读长和长读长测序获得了完整基因组。发现该抗性基因编码在一个IncHI2型超级质粒上，该质粒赋予对包括β-内酰胺类（ESBL）在内的六类抗生素的抗性。尽管存在该抗性基因，但该分离株对黏菌素仍保持敏感，这可能是由于基因组中不存在兼容的调控基因。该抗性基因的存在用常规临床程序即表型试验无法检测到。这表明该病房可能正在发生隐匿性传播。据我们所知，这是对多重耐药的该菌种以及编码任何可移动黏菌素抗性基因的该菌种的首次描述。
