We characterized by whole-genome sequencing (WGS) six carbapenem-resistant Acinetobacter baumannii strains isolated from a Brazilian tertiary hospital during a 14-day period. The ISAba1-bla_OXA-23 structure was found in the chromosome of five isolates, whereas bla_OXA-72 was inserted in a 16.6-kb plasmid in two isolates. The presence of ISAba1-bla_ADC-like justified the high broad-spectrum cephalosporins minimal inhibitory concentrations (MICs) (MIC₅₀, > 512 mg/L) verified in all isolates. Only minocycline (MIC₅₀, ≤ 0.5 μg/mL), polymyxin B (MIC₅₀, 0.5 μg/mL), and tigecycline (MIC₅₀, 0.5 μg/mL) were in vitro active against such isolates. A diversity of other antimicrobial resistance determinants (aph(3′)-VIa, aadA1, aac(3′)-IIa, strA, strB, sul2, drfA1, mph(E), msr(E), tetB, and floR) was also observed, which may confer resistance to at last six distinct antimicrobial classes. Four distinct pulsed-field gel electrophoresis (PFGE) profiles were observed during the study period, which belonged to ST79/ST258 (n = 2; IC5), ST25/ST229 (n = 2; IC7), ST1 (n = 1; IC1), and ST162/ST235 (n = 1; IC4). Although the ST1 isolate that carried bla_OXA-23 and bla_OXA-72 was introduced in this hospital setting by a transferred patient, two clonally related ST79/ST258 isolates carrying either one of these carbapenemase encoding genes were recovered from two patients who were hospitalized within the same period of time in the same hospital unit. Finally, a good correlation between PFGE/MLST, bla_OXA-51 variant, and single nucleotide polymorphisms was also observed. Here we demonstrated that distinct extensively drug-resistant A. baumannii clones can circulate in the same hospital setting during a short time period, illustrating a very complex epidemiological scenario for this priority pathogen.

中文翻译：

---

巴西某三级医院高危鲍曼不动杆菌主要克隆的短期动态

我们通过全基因组测序 (WGS)在 14 天内从巴西一家三级医院分离出六株耐碳青霉烯鲍曼不动杆菌菌株。在五个分离株的染色体中发现了IS Aba1 - bla _OXA-23结构，而在两个分离株中bla _OXA-72插入到一个 16.6-kb 的质粒中。IS Aba1 - bla _ADC样的存在证明了在所有分离株中验证的高广谱头孢菌素最小抑制浓度 (MIC) (MIC ₅₀ , > 512 mg/L)。仅米诺环素 (MIC ₅₀ , ≤ 0.5 μg/mL)、多粘菌素 B (MIC ₅₀, 0.5 μg/mL) 和替加环素 (MIC ₅₀ , 0.5 μg/mL)在体外对此类分离株具有活性。其他多种抗菌素耐药性决定因素（aph(3')-VIa、aadA1、aac(3')-IIa、strA、strB、sul2、drfA1、mph(E)、msr(E)、tetB和floR）是还观察到，这可能赋予对至少六种不同抗菌药物类别的抗性。在研究期间观察到四种不同的脉冲场凝胶电泳 (PFGE) 曲线，分别属于 ST79/ST258 ( n  = 2; IC5)、ST25/ST229 ( n = 2; IC7）、ST1（n  = 1；IC1）和 ST162/ST235（n  = 1；IC4）。虽然携带bla _OXA-23和bla _OXA-72的 ST1 分离株是由一名转院患者引入该医院的，但从两名住院患者身上回收了两种携带这些碳青霉烯酶编码基因之一的无性系相关 ST79/ST258 分离株。在同一医院单位的同一时间段。最后，还观察到PFGE/MLST、bla _OXA-51变体和单核苷酸多态性之间的良好相关性。在这里，我们证明了独特的广泛耐药鲍曼不动杆菌 克隆可以在短时间内在同一医院环境中传播，说明这种优先病原体的流行病学情况非常复杂。