Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) is a major cause of nosocomial infections and hospital outbreaks worldwide, remaining a critical clinical concern. Here we characterized and investigated the phylogenetic relationships of 105 CRAB isolates from an intensive care unit from one hospital in China collected over six years. All strains carried blaOXA-23, blaOXA-66 genes for carbapenem resistance, also had high resistance gene, virulence factor, and insertion sequence burdens. Whole-genome sequencing revealed all strains belonged to ST2, the global clone CC2. The phylogenetic analysis based on the core genome showed all isolates were dominated by a single lineage of three clusters and eight different clones. Two clones were popular during the collection time. Using chi-square test to identify the epidemiologically meaningful groupings, we found the significant difference in community structure only existed in strains from separation time. The haplotype and median-joining network analysis revealed genetic differences appeared among clusters and changes occurred overtime in the dominating cluster. Our results highlighted substantial multidrug-resistant CRAB burden in the hospital ICU environment demonstrating potential clone outbreak in the hospital.
Highlights
The spread of antibiotic-resistant bacteria poses a substantial public health crisis worldwide
A total of 302 A. baumannii strains were isolated from the hospital intensive care units (ICUs) rooms, and 105 isolates showed resistant to imipenem and meropenem (Supplementary Figure 1)
Hospitalized patients with open wounds and long hospital stays are among those who are vulnerable to A. baumannii infections, especially those hospitalized in intensive care units (ICU) (Sunenshine et al, 2007; Kamali et al, 2020)
Summary
The spread of antibiotic-resistant bacteria poses a substantial public health crisis worldwide. Acinetobacter baumannii, known as a member of the ESKAPE group, is responsible for a vast array of nosocomial infections throughout the world (Santajit and Indrawattana, 2016). The extraordinary ability to survive in a harsh environment and to readily acquire antimicrobial resistance determinants has made A. baumannii as a public health threat (Garnacho-Montero and Timsit, 2019). Carbapenems are known as the frontline treatment for multidrug-resistant (MDR). The widespread carbapenem resistant A. baumannii (CRAB) strains have caused a major concern worldwide due to the limited treatment choices (Doi, 2019). In 2017, the World Health Organization has listed CRAB as one of the most critical pathogens and the highest priority in new antibiotic development (Tacconelli et al, 2018)
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