Abstract：
BACKGROUND: Acinetobacter baumannii international clone II (IC2) is a widespread pandemic clone, however, it is rarely described in South America. The present study reported an outbreak caused by XDR IC2 strains in a clinical setting in Rio de Janeiro in 2022.
METHODS: Molecular epidemiology analysis was conducted with MLST to determine the clonal relationship and to assign a sequence type. The antimicrobial resistance profile of A. baumannii strains was assessed by the disk-diffusion method and MIC determination, and the presence of antibiotic resistance genes was determined by PCR and Sanger sequencing. The whole genome of one representative strain (AB91) was sequenced to prospect its resistome and virulome.
RESULTS: The MLST revealed that all strains belonged to the ST2 (Pasteur scheme) that corresponded to the pandemic IC2 lineage. They presented the XDR phenotype, which was compatible with their resistome composed of several acquired resistance genes and altered housekeeping genes. Additionally, an expressive virulome was revealed in AB91 genome. Genomic comparison with the unique other available IC2 genome from Brazil revealed that outbreaks occurring during (São Paulo - 2020/2021) and after (Rio de Janeiro - 2022) COVID-19 pandemics were caused by the same IC2 lineage.
CONCLUSIONS: This study suggests that the presence of a huge arsenal of resistance and virulence genes may have contributed to the persistence and the successful establishment of IC2 in Brazilian clinical settings during and after the COVID-19 pandemics in response to a series of events, such as the antibiotic overused during that period.
METHODS: Molecular epidemiology analysis was conducted with MLST to determine the clonal relationship and to assign a sequence type. The antimicrobial resistance profile of A. baumannii strains was assessed by the disk-diffusion method and MIC determination, and the presence of antibiotic resistance genes was determined by PCR and Sanger sequencing. The whole genome of one representative strain (AB91) was sequenced to prospect its resistome and virulome.
RESULTS: The MLST revealed that all strains belonged to the ST2 (Pasteur scheme) that corresponded to the pandemic IC2 lineage. They presented the XDR phenotype, which was compatible with their resistome composed of several acquired resistance genes and altered housekeeping genes. Additionally, an expressive virulome was revealed in AB91 genome. Genomic comparison with the unique other available IC2 genome from Brazil revealed that outbreaks occurring during (São Paulo - 2020/2021) and after (Rio de Janeiro - 2022) COVID-19 pandemics were caused by the same IC2 lineage.
CONCLUSIONS: This study suggests that the presence of a huge arsenal of resistance and virulence genes may have contributed to the persistence and the successful establishment of IC2 in Brazilian clinical settings during and after the COVID-19 pandemics in response to a series of events, such as the antibiotic overused during that period.
摘要：
背景：鲍曼不动杆菌国际克隆II（IC2）是一种广泛流行的克隆，然而,它很少在南美洲描述。本研究报道了2022年在里约热内卢的临床环境中由XDRIC2菌株引起的爆发。
方法：使用MLST进行分子流行病学分析，以确定克隆关系并分配序列类型。通过纸片扩散法和MIC测定评估鲍曼不动杆菌的耐药性，通过PCR和Sanger测序确定抗生素抗性基因的存在。对一个代表性菌株（AB91）的全基因组进行测序，以展望其抗性和病毒组。
结果：MLST显示所有菌株都属于ST2（巴斯德方案），与大流行IC2谱系相对应。他们展示了XDR表型，与由几个获得性抗性基因和改变的管家基因组成的抗性组相容。此外,在AB91基因组中发现了一个表达性病毒组.基因组与巴西独特的其他可用IC2基因组的比较表明，在(圣保罗-2020/2021)和(里约热内卢-2022)COVID-19大流行期间发生的疫情是由相同的IC2谱系引起的。
结论：这项研究表明，在COVID-19大流行期间和之后，巴西临床环境中存在巨大的抗性和毒力基因库可能有助于IC2的持续存在和成功建立，以应对一系列事件，比如那个时期过度使用的抗生素。
方法：使用MLST进行分子流行病学分析，以确定克隆关系并分配序列类型。通过纸片扩散法和MIC测定评估鲍曼不动杆菌的耐药性，通过PCR和Sanger测序确定抗生素抗性基因的存在。对一个代表性菌株（AB91）的全基因组进行测序，以展望其抗性和病毒组。
结果：MLST显示所有菌株都属于ST2（巴斯德方案），与大流行IC2谱系相对应。他们展示了XDR表型，与由几个获得性抗性基因和改变的管家基因组成的抗性组相容。此外,在AB91基因组中发现了一个表达性病毒组.基因组与巴西独特的其他可用IC2基因组的比较表明，在(圣保罗-2020/2021)和(里约热内卢-2022)COVID-19大流行期间发生的疫情是由相同的IC2谱系引起的。
结论：这项研究表明，在COVID-19大流行期间和之后，巴西临床环境中存在巨大的抗性和毒力基因库可能有助于IC2的持续存在和成功建立，以应对一系列事件，比如那个时期过度使用的抗生素。
