Which Bacterial Agent Is More Influential in the Development of Retinopathy of Prematurity: Gram-Positive or Gram-Negative?

Objective: In addition to hyperoxia, inflammation and infection contribute to the pathogenesis of retinopathy of prematurity (ROP). However, the differential effects of specific bacterial pathogens on ROP development remain unclear. This study aimed to evaluate the association between sepsis due to Gram-positive and Gram-negative bacteria and the development and severity of ROP. Materials and Methods: Infants at risk for ROP, defined as those with birth weight ≤1500 g or gestational age ≤32 weeks, or those with birth weight >1500 g or gestational age >32 weeks who required cardiorespiratory support, were included in this retrospective study. Patients were categorised into no-ROP and any-stage ROP groups, as well as treatment-requiring and non-treatment-requiring ROP groups. The clinical characteristics, laboratory findings, and microbiological data were compared between the groups. Results: Among the 319 enrolled infants, 193 (60.6%) did not develop ROP, whereas 126 (39.4%) developed any-stage ROP. Clinical early-onset sepsis, clinical and proven late-onset sepsis, and increased frequency of late-onset sepsis episodes were significantly associated with any-stage and treatment-requiring ROP (p < 0.05). In multivariate analysis, both Gram-positive (OR 2.36, 95% CI 1.2-4.6, p = 0.012) and Gram-negative bacterial sepsis (OR 3.56, 95% CI 1.5-8.3, p = 0.004) were independently associated with any-stage ROP. In addition, Gram-positive bacterial sepsis (OR 4.4, 95% CI 1.1-16.9, p = 0.031) was independently associated with treatment-requiring ROP. Conclusions: Gram-positive bacterial sepsis was associated with both any-stage ROP and treatment-requiring ROP, whereas Gram-negative bacterial sepsis was associated with any-stage ROP only. These findings support the potential role of pathogen-specific inflammatory processes in ROP development and progression. Further prospective studies incorporating detailed inflammatory and oxygenation parameters are required to clarify these relationships.