目的 研究新生儿重症监护室（NICU）晚发型败血症（LOS）的病原菌分布、变迁及耐药情况。方法 回顾性分析2012年1月至2019年12月NICU收治的223例血培养阳性LOS新生儿的临床资料,分析病原菌逐年变迁特点。结果 223例新生儿中男116例、女107例,平均胎龄（31.9±1.2）周,平均出生体质量（1 584.1±620. 9）g,发生LOS的中位年龄为19.0（13.0~27.0）d,早产儿203例、足月儿20例。共检出234株病原菌,以G^-菌检出最多（128株,54.7%）,其中肺炎克雷伯杆菌77株;G⁺菌69株（29.5%）;真菌37株（15.8%）。不同年份之间G^-菌、G⁺菌以及真菌检出率差异有统计学意义（P<0.01）,G^-菌和真菌均以2016年检出率最高,G⁺菌以2014年检出率最高。G⁺菌、G^-菌及真菌组之间发病时间、剖宫产率、胎膜早破时间>18 h、抗生素暴露率及病死率差异均有统计学意义（P<0.05）。G^-菌的剖宫产率、病死率较高,发病时间较短;真菌组抗生素暴露率、胎膜早破时间>18 h比例较高。肺炎克雷伯杆菌（34.9%）是引起早产儿LOS最常见致病菌。早产儿和足月儿组之间G^-菌、G⁺菌以及真菌检出率的分布差异无统计学意义（P>0.05）。检出多重耐药菌共109株（46.6%）,以ESBLs肠杆菌为主（74株,67.9%）。结论 G^-菌是NICU中引起LOS的常见病原菌,对常用抗菌药物耐药严重。定期回顾分析NICU中病原菌分布及耐药特点有助于指导抗生素的合理及有效使用。

Objective To analyze the distribution, changes and drug resistance of pathogenic bacteria in late-onset sepsis (LOS) in neonatal intensive care unit (NICU). Methods The clinical data of 223 LOS neonates with positive blood culture admitted to NICU from January 2012 to December 2019 were retrospectively analyzed, and the changes of pathogenic bacteria from year to year were analyzed. Results Among 223 neonates (116 boys and 107 girls), the mean gestational age was (31.9±1.2) weeks, the mean birth weight was (1584.1± 620.9) g, and the median age of LOS was 19.0 (13.0-27.0) days. There were 203 preterm infants and 20 full-term infants. A total of 234 pathogenic strains were detected, most of which were G^- bacteria (128 strains, 54.7%), including 77 strains of Klebsiella pneumoniae. Sixty-nine strains (29.5%) were G⁺ bacteria and 37 strains (15.8%) were fungi. There were significant differences in the detection rates of G^- bacteria, G⁺ bacteria and fungi among different years (P<0.01). The highest detection rates of G^- bacteria and fungi were found in 2016, and the highest detection rates of G⁺ bacteria were found in 2014. The onset time, cesarean section rate, time of premature rupture of membranes >18 hours, antibiotic exposure rate and mortality among G⁺ bacteria, G^- bacteria and fungi groups were significantly different (P<0.05). The cesarean section rate and mortality were higher, and the onset time was shorter in G^- bacteria group. The rate of antibiotic exposure and the proportion of premature rupture time >18 hours were higher in fungi group. Klebsiella pneumoniae (34.9%) was the commonest pathogen causing LOS in premature infants. There was no significant difference in the detection rates of G^- bacteria, G⁺ bacteria and fungi between premature and full-term infants (P>0.05). A total of 109 strains (46.6%) of multiple drug-resistant bacteria were detected and extended-spectrum β-lactamase (ESBLs)-producing Enterobacteriaceae was the dominant strain (74 strains, 67.9%). Conclusions G^- bacteria are the common pathogens causing LOS in NICU, and have serious resistance to commonly used antibiotics. Retrospective analysis of pathogen distribution and resistance characteristics in the NICU on a regular basis is helpful to guide the rational and effective use of antibiotics.