Streptococcus sp. in neonatal endotracheal tube biofilms is associated with ventilator-associated pneumonia and enhanced biofilm formation of Pseudomonas aeruginosa PAO1

Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation leading to high morbidity and mortality among intubated neonates in neonatal intensive care units (NICUs). Endotracheal tube (ETT) biofilm flora were considered to be responsible for the occurrence of VAP as a reservoir of pathogens. However, regarding neonates with VAP, little is known about the complex microbial signatures in ETT biofilms. In the present study, a culture-independent approach based on next generation sequencing was performed as an initial survey to investigate the microbial communities in ETT biofilms of 49 intubated neonates with and without VAP. Our results revealed a far more complex microflora in ETT biofilms from intubated neonates compared to a previous culture-based study. The abundance of Streptococci in ETT biofilms was significantly related to the onset of VAP. By isolating Streptococci in ETT biofilms, we found that Streptococci enhanced biofilm formation of the common nosocomial pathogen Pseudomonas aeruginosa PAO1 and decreased IL-8 expression of airway epithelia cells exposed to the biofilm conditioned medium of PAO1. This study provides new insight into the pathogenesis of VAP among intubated neonates. More studies focusing on intubated neonates are warranted to develop strategies to address this important nosocomial disease in NICUs.