Abstract： Objective:To analyse the pathogenic bacteria distribution and clinical characteristics of late-onset sepsis (LOS) among premature infants with gestational age less than 34 weeks in Henan Province.Methods:The clinical data of 6 590 premature infants admitted to 17 medical institutions in Henan Province from January 2019 to December 2020 were retrospectively analyzed. The gestational age of infants was less than 34 weeks and was admitted to the neonatal ward within 7 days after birth. SPSS 19.0 statistical software was used for data analysis.Results:Among 6 590 premature infants LOS developed in 751 cases (11.40%), of whom the diagnosis was confirmed in 276 cases (36.75%) and 475 cases (63.25%) were diagnosed clinically. The fatality rate related to LOS was 13.58%. There were significant differences in the incidence of LOS and infection-related mortality among infants with different gestational ages and body weights ( χ2=388.894 and 13.572, χ2=472.282 and 9.257, P<0.05 or <0.01). Among 276 children with confirmed LOS, 286 strains of pathogenic bacteria were isolated. Gram-negative bacteria were most prevalent (178 strains), accounting for 62.24% of all infections, followed by fungi (58 strains, 20.28%). Klebsiella pneumoniae was most frequently detected Gram-negative bacteria (117 strains, 40.91%), among which 32.48% (38/117) was carbapenem-resistant Klebsiella pneumoniae. The proportion of diagnosed sepsis, the proportion of catheterization, and the infection-related mortality of infants with LOS in tertiary hospitals were all higher than those in secondary hospitals ( χ2=6.212, 5.313 and 4.435, all P<0.05). The proportion of exclusive breastfeeding in secondary hospitals was lower than that in tertiary hospitals ( χ2=19.216, P<0.05). The time of antibacterial drug use before infection in specialized hospitals was longer than that in general hospitals ( χ2=3.276, P<0.05). Conclusion:The incidence of LOS among preterm infants in Henan Province is high, which was mainly caused by Gram-negative bacteria. The clinical characteristics of LOS caused by different pathogens and in different health institutions are different, the prevention and control strategy should be developed accordingly to reduce the incidence LOS of preterm premature infants.