Characterization of a carbapenem- resistant Citrobacter amalonaticus coharbouring blaIMP-4 and qnrs1 genes
Characterization of a carbapenem- resistant Citrobacter amalonaticus coharbouring blaIMP-4 and qnrs1 genes
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DOI：
10.1099/jmm.0.001364
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发表时间：
2021-01-01
影响因子：
3
通讯作者：
Zhao, Zhigang
中科院分区：
文献类型：
--
作者：
Zhao, Yunan;Chen, Xuefeng;Zhao, Zhigang
导论.柠檬酸杆菌属的成员是属于肠球菌目的兼性厌氧革兰氏阴性杆菌[Janda J Clin Microbiol 1994; 32（8）：1850-1854; Arens Clin Microbiol Infect 1997;3（1）：53-57]。以前，柠檬酸杆菌属偶尔被报告为低毒力的医院病原体[Pepperell Antimicrob Agents Chemother 2002;46（11）：3555-60]。现在，它们一直被报道引起泌尿道、呼吸道、骨、腹膜、内膜、脑膜、肠、血流和中枢神经系统的医院感染。在柠檬酸杆菌属中，最常见的分离株是C. koseri和C. freundii，而C.很少分离到嗜热链球菌[Janda J Clin Microbiol 1994; 32（8）：1850-1854; Marak Infect Dis（Lond）2017;49（7）：532-9]。此外，柠檬酸杆菌属（Citrobacter spp.）通常对碳青霉烯类、氨基糖苷类、四环素类和粘菌素敏感[Marak Infect Dis（Lond）2017;49（7）：532-9]。假设/差距声明。作为C.耐碳青霉烯类抗生素菌株是一种罕见的耐药菌株，目前仅分离到1株同时携带碳青霉烯类抗生素耐药基因bla（IMP-4）和喹诺酮类抗生素耐药基因qnrs 1的临床分离株。对碳青霉烯类耐药的C.共携带bla（IMP-4）和qnrs 1的中国嗜热链球菌菌株。2011-2018年期间收集了340株非重复碳青霉烯类耐药肠球菌（CRE）菌株。对碳青霉烯类抗生素耐药的C.使用基于VITEK质谱的微生物鉴定系统和16 S rRNA测序检测并确认了嗜热链球菌菌株。通过肉汤微量稀释法获得临床抗菌药物的最低抑菌浓度（MIC）。利用全基因组测序技术分析了耐药基因，并构建了系统发育树。使用细菌全基因组分析（BPGA）工具构建嗜热链球菌菌株。用接合转移法验证了抗性质粒的可转移性。一种罕见的碳青霉烯类耐药C.从一例脑梗塞患者体内分离到一株嗜热链球菌（CA 71），其16 S rRNA基因序列与C.第165章. CA 71对β-内酰胺类、喹诺酮类和氨基糖苷类抗生素耐药，甚至对亚胺培南和美罗培南耐药（MIC分别为2和4 mg l（-1）），仅对多粘菌素B和替加环素敏感。WGS法检测到6种抗生素耐药基因，包括β-内酰胺类基因bla（IMP-4）、bla（CTX-M-18）和bla（Sed 1），喹诺酮类基因qnrs 1，氨基糖苷类基因AAC（3）-VIIIa、AadA 24。有趣的是，bla（IMP-4）和qnrs 1共存于IncN 1型质粒（pCA 71-IMP）上，并通过接合转移成功地转移到大肠杆菌J53中。系统发育分析表明，CA 71与C.与其他7个菌株沿着属于同一进化簇。据我们所知，这是第一个碳青霉烯类耐药的C。共携带bla（IMP-4）和qnrs 1的嗜热链球菌分离株。
Introduction. Members of the genus Citrobacter are facultative anaerobic Gram-negative bacilli belonging to the Enterobacterales [Janda J Clin Microbiol 1994; 32(8):1850-1854; Arens Clin Microbiol Infect 1997;3(1):53-57]. Formerly, Citrobacter species were occasionally reported as nosocomial pathogens with low virulence [Pepperell Antimicrob Agents Chemother 2002;46(11):3555-60]. Now, they are consistently reported to cause nosocomial infections of the urinary tract, respiratory tract, bone, peritoneum, endocardium, meninges, intestines, bloodstream and central nervous system. Among Citrobacter species, the most common isolates are C. koseri and C. freundii, while C. amalonaticus has seldom been isolated [Janda J Clin Microbiol 1994; 32(8):1850-1854; Marak Infect Dis (Lond) 2017;49(7):532-9]. Further, Citrobacter spp. are usually susceptible to carbapenems, aminoglycosides, tetracyclines and colistin [Marak Infect Dis (Lond) 2017;49(7):532-9].Hypothesis/Gap Statement. As C. amalonaticus is rare, only one clinical isolate, coharbouring carbapenem resistance gene bla(IMP-4) and quinolone resistance gene qnrs1, has been reported.Aim. To characterize a carbapenem-resistant C. amalonaticus strain from PR China coharbouring bla(IMP-4) and qnrs1.Methodology. Three hundred and forty nonrepetitive carbapenem-resistant Enterobacterales (CRE) strains were collected during 2011-2018. A carbapenem-resistant C. amalonaticus strain was detected and confirmed using a VITEK mass spectrometry-based microbial identification system and 16S rRNA sequencing. Minimum inhibitory concentrations (MICs) for clinical antimicrobials were obtained by the broth microdilution method. Whole-genome sequencing (WGS) was performed for antibiotic resistance gene analysis, and a phylogenetic tree of C. amalonaticus strains was constructed using the Bacterial Pan Genome Analysis (BPGA) tool. The transferability of the resistance plasmid was verified by conjugal transfer.Results. A rare carbapenem-resistant C. amalonaticus strain (CA71) was recovered from a patient with cerebral obstruction and the sequences of 16S rRNA gene shared more than 99% similarity with C. amalonaticus CITRO86, FDAARGOS 165. CA71 is resistant to beta-lactam, quinolone and aminoglycoside antibiotics, and even imipenem and meropenem (MICs of 2 and 4 mg l(-1) respectively), and is only sensitive to polymyxin B and tigecycline. Six antibiotic resistance genes were detected via WGS, including the beta-lactam genes bla(IMP-4), bla(CTX-M-18) and bla(Sed1), the quinolone gene qnrs1, and the aminoglycoside genes AAC(3)-VIIIa, AadA24. Interestingly, bla(IMP-4) and qnrs1 coexist on an IncN1-type plasmid (pCA71-IMP) and successfully transferred to Escherichia coli J53 via conjugal transfer. Phylogenetic analysis showed that CA71 is most similar to C. amalonaticus strain CJ25 and belongs to the same evolutionary cluster along with seven other strains.Conclusion. To the best of our knowledge, this is the first report of a carbapenem-resistant C. amalonaticus isolate coharbouring bla(IMP-4) and qnrs1.