Impact of Xpert® Carba-R – Based Screening for Carbapenem-Resistant Organisms on Infection-Related Mortality in Hematopoietic Stem Cell Transplant Recipients

Chenjing Qian¹Jiaxin Hong²Wei Shi¹Fang Liu¹Weiming Li¹Ling Ma³Xinghui Gao⁴Yi-Wei Tang⁴Qiuling Wu^1*Linghui Xia^1*Mei Hong^1*

• ¹Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
• ²Huazhong University of Science and Technology Tongji Medical College First Clinical College Union Hospital Tumor Center, Wuhan, China
• ³Huazhong University of Science and Technology Tongji Medical College Union Hospital, Wuhan, China
• ⁴University of Dayton College of Arts and Sciences, Dayton, United States

Background. The emergence of Carbapenem resistant organism (CRO) poses a major challenge to clinical infection control in hospitals. Patients undergoing hematopoietic stem cell transplants (HSCT) infected by CRO are at high risk of mortality.Methods. HSCT patients were screened only by rectal swab traditional CRO culture and CRO colonization was determined if rectal culture was positive. In study group from August 2021 to July 2022, two rectal swab specimens were collected from HSCT patients for both CRO traditional culture (RS-culture) and Xpert Carba-R testing (RS-Carba-R). CRO colonization was determined if either screening method was positive. CRO-active antibiotics were immediately provided on the first febrile episode of neutropenia (FN) in CRO colonized patients. Results. In the historic group, 47 out of 197 patients (23.9%) were identified as colonized with CRO, detected only by RS-culture. In the study group, 41 out of 184 patients (22.3%) were identified as colonized with CRO, detected by either RS-culture or RS-Carba-R, This indicated a slightly lower annual detection rate of CRO gut colonization in the study group compared to the historic group, but no significant difference was observed (22.3% vs 23.9%, p=0.715). The incidence of CRO-related bloodstream infections (CRO-BSI) was significantly lower in the study group compared to the historic group (4.8% vs 25.5%, p=0.012), and the CRO-related mortality in colonized patients decreased from 19.4% in the historic group to 2.4% in the study group (p=0.046).The monthly detection rate of CRO gut colonization by RS-culture in the historic group remained steady, with no significant fluctuation. In contrast, the monthly detection rate of CRO gut colonization by either RS-culture or RS-Carba-R in the study group was higher in the first month compared to the historic group. However, a gradual decline in the monthly detection rates of CRO gut colonization by RS-culture and/or RS-Carba-R was observed in the study group, dropping from 21.2% in the first month to 2.9% in the last month. Conclusions. Our study showed a positive effect of more rapid CRO colonization screening based on rectal swabs Xpert Carba-R and culture, and thus reduce the mortality and spread of CRO infection in HSCT patients.