Analysis of bacteriological characteristics of nosocomial infections in preterms based on Gram-negative infection factors.

INTRODUCTION: Nosocomial infections (NIs) in the neonatal intensive care unit (NICU) are a significant cause of disability or death in preterm infants. This study focused on the bacteriological characteristics of NIs in preterm infants based on blood culture, and the factors related to Gram-negative bacterial infection. METHODOLOGY: This retrospective study was conducted at the NICU in Renmin Hospital of Wuhan University from January 2020 to June 2024. The patients were divided into Gram-negative and Gram-positive bacteria groups based on Gram staining results. Logistic regression analysis was performed to identify the factors influencing Gram-negative bacterial infection, and the diagnostic value was evaluated based on the area under the receiver operating characteristic curve (AUC). RESULTS: A total of 54 strains (54/95, 56.84%) of Gram-positive bacteria and 41 strains (41/95, 43.16%) of Gram-negative bacteria were detected in the blood cultures of the 95 patients diagnosed with late-onset sepsis. The proportion of Gram-negative bacteria in the past 5 years exhibited a trend of initially decreasing and then increasing. Use of mechanical ventilation, decreased monocyte count, and elevated lactate levels were identified as factors predicting Gram-negative bacterial infection (p < 0.05). The AUC values of these factors for predicting Gram-negative bacterial infection were 0.56 (p < 0.05), 0.71 (p < 0.05), and 0.71 (p < 0.05), respectively. CONCLUSIONS: The proportion of Gram-negative bacterial infections showed a trend of initially decreasing and then increasing from 2020 to 2024. The use of mechanical ventilation, decreased monocyte counts, and elevated lactate levels were factors influencing Gram-negative bacterial infection.