Background: Acinetobacter baumannii  has emerged as an important pathogen associated with hospital- and community-acquired infections. Community-acquired A. baumannii  pneumonia is characterized by a fulminant course and high mortality rates. In this study, we report the identification of a community-acquired carbapenem-resistant A. baumannii  strain carrying the bla _OXA-72 gene.
Methods: This A. baumannii  isolate was recovered from a male patient diagnosed with community-acquired pneumonia, septic shock, and respiratory failure. Antimicrobial susceptibility testing were performed and the minimum inhibitory concentrations were determined by the broth microdilution method. Whole-genome sequencing was performed using both long-read MinION and short-read Illumina platforms to fully characterize the bla _OXA-72-carrying plasmid of the A. baumannii  A52. The in silico multilocus sequence typing and genomic epidemiological analysis of the closely related isolates were further elucidated by our recently updated BacWGSTdb server.
Results: The isolate was resistant to meropenem and remained susceptible to several other antimicrobial agents. Whole-genome sequencing and bioinformatics analysis indicated that this A. baumannii  isolate belonged to the rare sporadic clone sequence type 880 and the bla _OXA-72 gene was located on the 8,493-bp plasmid pA52-OXA-72. This plasmid exhibited only partial similarity to different OXA-72-encoding plasmids (size range: 8,771–12,056 bp) in various Acinetobacter  spp. recovered from patients and other reservoirs in different countries.
Conclusion: This study described the first case of fulminant carbapenem-resistant community-acquired A. baumannii  pneumonia caused by a rare sporadic clone in China. Adequate surveillance is warranted to monitor the emergence of A. baumannii  as a community pathogen.
Keywords: Acinetobacter baumannii , community-acquired pneumonia, bla _OXA-72 carbapenem resistance, plasmid