Clin Microbiol Infect. 2021 Jun 28:S1198-743X(21)00362-1. doi: 10.1016/j.cmi.2021.06.031. Online ahead of print.
OBJECTIVE: To investigate the hypothesis that intestinal colonization by different types of carbapenemase-resistant Klebsiella pneumoniae (CR-Kp) leads to different risks for BSI caused by the same colonizing organism.
METHODS: Prospective observational study including consecutive CR-Kp rectal carriers admitted to the Pisa University Hospital (Dec 2018-Dec 2019). Patients underwent rectal swabbing with molecular testing for the different carbapenemases at hospital admission and during the hospitalization. Rectal carriers were classified as: NDM, KPC, VIM and OXA-48. The primary endpoint was the rate of BSI by the same colonizing organism in each study group. A multivariate logistic regression analysis was performed to identify factors independently associated with the risk for BSI by the colonizing organism.
RESULTS: Of 677 rectal carriers, 382/677 (56.4%) were colonized by NDM, 247/677 (36.5%) by KPC, 39/677 (5.8%) by VIM and 9/677 (1.3%) by OXA-48. Dissemination of NDM-KP was mostly sustained by ST147, while KPC-kp belonged to ST512. A higher rate of BSI was documented in NDM-compared to KPC-rectal carriers (59/382, 15.4% vs 20/247, 8.1%, p=0.004). Incidence rates of BSI per 100 patients/month were significantly higher in the NDM (22.33, 95% CI 17.26-28.88) than in the KPC group (9.56, 95% CI 6.17-14.82). On multivariate analysis, multi-site extra-intestinal colonization, solid organ transplantation, invasive procedures, intravascular device, ICU, cephalosporin, fluoroquinolones and NDM rectal colonization (OR 3.27, 95% CI 1.73-6.18, p<0.001) were independently associated with BSI.
CONCLUSIONS: NDM-Kp was associated with increased risk of BSI compared to KPC-Kp. This finding seems to be strongly related to the high risk clone ST147.