Clinical infection and molecular characteristics of carbapenem-resistant organisms among children in China, 2016-2025

Abstract

Carbapenem-resistant organisms (CROs) pose a severe health threat to pediatric patients. We aimed to investigate the epidemiology, clinical infection, and molecular profiles of CROs in Chinese children from 2016 to 2025. We retrospectively analyzed 3655 non-duplicate CRO strains isolated from Children’s Hospital of Fudan University between 2016 and 2025, and further selected 499 carbapenem-resistant Enterobacterales (CRE) strains and 315 single or multiple CRO infection cases to investigate the characteristics of different CROs. The predominant CRO pathogens included carbapenem-resistant A. baumannii (CRAB, 28.5%), K. pneumoniae (CRKP, 27.9%) and P. aeruginosa (CRPAE, 15.6%). CROs were predominantly recovered from the ICU and neonatology departments, with neonates and infants constituting the major population (60.2%). All CROs were highly resistant to most tested antimicrobials, but showed low-resistance to tigecycline (0%–0.8%) and polymyxin B (0.5%–8%). CRKP predominated in blood (36.9%) and urine (44.9%), whereas CRAB was frequently isolated from lower respiratory tract (40.0%) and cerebrospinal fluid (58.3%). The prevalence of CRAB and CRPAE declined gradually between 2016 and 2025, while CRKP experienced a marked resurgence after the COVID-19 pandemic. bla NDM-1 (36.1%), bla NDM-5 (28.5%) and bla KPC-2 (26.9%) were the dominant carbapenemase genes of CREs, with ST11-KPC-KP as the major CRKP subtype. bla KPC-2 were linked to invasive infections (52.9%), whereas bla NDM were associated with noninvasive infections (53.8%~78.8%). In univariate comparisons, multiple CRO infections were associated with older age, elevated WBC and CRP levels, and a higher proportion of bla KPC carriage than single infection. Multivariable logistic regression revealed that prolonged hospitalization, higher WBC and CRP levels were independently associated with multiple CRO infection (all p < 0.05). In contrast, bla KPC and bla NDM carriage were significant risk factors for single CRO infection (both p < 0.01). Additionally, both elevated WBC level and multiple CRO infection were strongly correlated with severe disease ( p < 0.05). bla NDM was the predominant carbapenemase among pediatric CRO strains, yet bla KPC-2 was more prevalent in invasive infections. Multiple CRO infection was independently correlated with severe illness, highlighting the importance of continuous surveillance on multiple CRO infection among children.