Hospital-Acquired Pneumonia in Newborns with Birth Weight Less Than 1500 Grams: Risk Factors and Causes

Abstract Low birth weight newborns (≤1500 grams) are at a high risk of acquiring hospital infections due to the immaturity of the immune system, lack of efficient structural barriers, and an incomplete development of endogenous microbial flora. The aim of this study was to reveal the potential risk factors for hospital-acquired pneumonia in low birth weight newborns. This study was a prospective cohort design with a nested case-control study and was conducted between January 1st, 2012 and June 30th, 2015 at the Neonatology Department, Clinical Centre Kragujevac, Serbia. There were 1140 newborns hospitalized at the Neonatology Department for longer than 48 hours during the study period, and 169 of them (14.82%) weighed less than 1500 grams at birth. In total, 73 (43.19%) newborns with low birth weights developed HIs. The most prevalent HI was hospital pneumonia (n=64, 87.67%). Although univariate analyses identified many risk factors with a significant influence on the occurrence of hospital pneumonia, multivariate analysis identified only the following two independent risk factors for hospital pneumonia in newborns with birth weights below 1500 grams: mechanical ventilation (p=0.003, OR=68.893, 95% CI=4.285-1107.699) and longer hospitalization (p=0.003, OR=1.052, 95% CI=1.017-1.088). Almost all of the pathogens isolated from the patients with pneumonia were gram-negative bacteria (98.50%). More than half of all of the isolates were Acinetobacter spp (37.50%) and Enterobacter spp (18.75%). Our study showed that mechanical ventilation and prolonged hospitalization were significant risk factors for the development of hospital pneumonia in newborns with birth weights below 1500 grams.