Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand.
Department of Clinical Chemistry, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand.
Front Cell Infect Microbiol. 2023 Jan 4;12:1067572. doi: 10.3389/fcimb.2022.1067572. eCollection 2022.
spp. are Gram-negative bacteria commonly found in environments and intestinal tracts of humans and animals. They are generally susceptible to third-generation cephalosporins, carbapenems and colistin. However, several antibiotic resistant genes have been increasingly reported in spp., which leads to the postulation that spp. could potentially be a reservoir for spreading of antimicrobial resistant genes. In this study, we characterized two colistin-resistant spp. isolated from the feces of a healthy individual in Thailand. Based on MALDI-TOF and ribosomal multilocus sequence typing, both strains were identified as and . Genomic analysis and S1-nuclease pulsed field gel electrophoresis/DNA hybridization revealed that and harbored gene on pSY_CS01 and pSY_CA01 plasmids, respectively. Both plasmids belonged to IncFII(pCoo) replicon type, contained the same genetic context (TnISΔTnAsIS) and exhibited high transferring frequencies ranging from 1.03×10 - 4.6×10 CFU/recipient cell J53. Colistin-MICs of transconjugants increased ≥ 16-fold suggesting that on these plasmids can be expressed in other species. However, beside , other major antimicrobial resistant determinants in multidrug resistant Enterobacterales were not found in these two isolates. These findings indicate that gene continued to evolve in the absence of antibiotics selective pressure. Our results also support the hypothesis that could be a reservoir for spreading of antimicrobial resistant genes. To the best of our knowledge, this is the first report that discovered human-derived spp. that harbored but no other major antimicrobial resistant determinants. Also, this is the first report that described the presence of gene in and in .
spp. 是一种常见于人类和动物环境及肠道中的革兰氏阴性细菌。它们通常对第三代头孢菌素、碳青霉烯类和黏菌素敏感。然而，越来越多的报道表明， spp. 中存在几种抗生素耐药基因，这使得人们推测 spp. 可能是抗生素耐药基因传播的潜在储库。在这项研究中，我们从泰国一位健康个体的粪便中分离出两株耐多粘菌素的 spp.，并对其进行了特征描述。基于 MALDI-TOF 和核糖体多位点序列分型，这两株菌均被鉴定为 和 。基因组分析和 S1-核酸酶脉冲场凝胶电泳/DNA 杂交显示， 和 分别在质粒 pSY_CS01 和 pSY_CA01 上携带 基因。这两个质粒均属于 IncFII(pCoo)复制子类型，含有相同的遗传结构（TnISΔTnAsIS），并且在 J53 中具有较高的转移频率（1.03×10 - 4.6×10 CFU/受体细胞）。转导子的多粘菌素 MIC 增加了≥16 倍，表明这些质粒上的 基因可以在其他物种中表达。然而，除了 之外，这两个分离株中未发现其他主要的多药耐药肠杆菌科的抗生素耐药决定因素。这些发现表明，在没有抗生素选择性压力的情况下， 基因仍在不断进化。我们的结果也支持了这样一种假设，即 spp. 可能是抗生素耐药基因传播的潜在储库。据我们所知，这是首次报道发现携带 但不携带其他主要抗生素耐药决定因素的人类源 spp.。此外，这也是首次报道描述了 和 中存在 基因的情况。
