Background: Carbapenem-resistant Enterobacteriaceae (CRE) prevalence in neonatal patients continues to rise in china. However, very few epidemiological data are available to uncover the underlying mechanisms for the increase. This study aimed to elucidate their transmission modes and explore potential sources. Methods: The genotypic features of CRE isolates were analyzed by PCR and sequencing. The elucidation of transmission and sources involved in electronic medical record review, environmental cultures, screening cultures, and prospective case-control analysis. The transferability of carbapenem-resistant genes was performed by Conjugation experiments.Results: A total of 450 CRE isolates recovered from 369 infant patients were genotypically characterised. Carbapenemase genes NDM-1, KPC-2 and IMP-4 accounted for 86.22% (n = 388), 8.89% (n = 40) and 4.44% (n = 20), respectively. After implementation of intensified control measures, CRE rectal prevalence rates in both the 0-3 days and the 4-28 days age group were decreased from 15.53% (100/644) and 27.37% (52/190) to 11.78% (51/433) and 19.59% (19/97) (P = 0.082 and P = 0.148), respectively. Multivariate analysis showed that gastric lavage (odds ratio [OR]) 3.09, 95% confidence interval [CI] 1.49–6.39) and enema (OR 2.84, 95% CI 1.65–4.91) were independent risk factors for rectal colonisation in the 0-3 days age group, whereas Cephalosporins (OR 2.12, 95% CI 1.14–3.94), gastric lavage (OR 3.44, 95% CI 1.44–8.22) and residence in rural area (OR 2.22, 95% CI 1.19–4.13) were independently associated with rectal colonization in the 4-28 days age group. The transmission tracking of neonatal NDM-1 strains outbreaks revealed rivers contaminated with NDM genes. Most isolates with NDM genes could be successfully transferred.Conclusion: Continued vigilance for importations should be maintained to reduce CRE threat.

Background Carbapenem-resistant Enterobacteriaceae (CRE) prevalence in neonatal patients continues to rise in china. However, very few epidemiological data are available to uncover the underlying mechanisms for the increase. This study aimed to elucidate their transmission modes and explore potential sources. Methods The genotypic features of CRE isolates were analyzed by PCR and sequencing. The elucidation of transmission and sources involved in electronic medical record review, environmental cultures, screening cultures, and prospective case-control analysis. Results A total of 450 CRE isolates recovered from 369 infant patients were genotypically characterised. Carbapenemase genes NDM-1, KPC-2 and IMP-4 accounted for 86.22% (n = 388), 8.89% (n = 40) and 4.44% (n = 20), respectively. After implementation of intensified control measures, CRE rectal prevalence rates in both the 0–3 days and the 4–28 days age group were decreased from 15.53% (100/644) and 27.37% (52/190) to 11.78% (51/433) and 19.59% (19/97) (P = 0.082 and P = 0.148), respectively. Multivariate analysis showed that gastric lavage (odds ratio [OR]) 3.09, 95% confidence interval [CI] 1.49–6.39) and enema (OR 2.84, 95% CI 1.65–4.91) were independent risk factors for rectal colonisation in the 0–3 days age group, whereas Cephalosporins (OR 2.12, 95% CI 1.14–3.94), gastric lavage (OR 3.44, 95% CI 1.44–8.22) and residence in rural area (OR 2.22, 95% CI 1.19–4.13) were independently associated with rectal colonization in the 4–28 days age group. The strict management of aseptic procedures eventually halted the silent spread. The transmission tracking of neonatal NDM-1 strains outbreaks revealed rivers contaminated with NDM genes. Conclusions Continued vigilance for importations should be maintained to reduce CRE threat. Community awareness raising campaigns are urgently needed to reduce CRE threat.