Successful Treatment of an AML Patient Infected with Hypervirulent ST463 Pseudomonas Aeruginosa Harboring Rare Carbapenem-Resistant Genes blaAFM-1 and blaKPC-2 Following Allogeneic Hematopoietic Stem Cell Transplantation

Background: Carbapenem-resistant P. aeruginosa (CRPA) is a common hospital-acquired bacterium.It exhibits high resistance to many antibiotics, including ceftazidime/avibactam and cefteolozane/tazobactam.The presence of carbapenem-resistant genes and coexistence Klebsiella pneumoniae carbapenemase (KPC) and metallo-β-lactamases (MBLs) further inactivated all β-lactams.Understanding the resistance genes of CRPA can help in uncovering the resistance mechanism and guiding anti-infective treatment.Herein, we reported a case of perianal infection with hypervirulent ST463 Pseudomonas aeruginosa.Case Presentation: The case is a 32-year-old acute myeloid leukemia (AML) patient with fever and septic shock during hematopoietic stem cell transplantation (HSCT), and the pathogen was finally identified as a highly virulent sequence type 463 (ST463) P. aeruginosa harboring carbapenem-resistant genes bla AFM-1 and bla KPC-2 , which was detected in the bloodstream and originated from a perianal infection.The strain was resistant to ceftazidime/avibactam but successfully treated with polymyxin B, surgical debridement, and granulocyte engraftment after HSCT.The AML was cured during the 19-month follow-up.Conclusion: This case emphasizes the importance of metagenomic next-generation sequencing (mNGS) and whole-genome sequencing (WGS) in identifying microbes with rare resistant genes, and managing CRPA, especially in immunocompromised patients.Polymyxin B may be the least resistant option.