Clinical analysis of throat swab culture in neonates

Objective To study the clinical significance of bacterial colonization in neonatal infection through intergrating the throat swab culture and other clinical data in admitted neonates within 24 hours. Methods The clinical data of 934 newborns (527 boys and 407 girls) who were admitted to Sichuan Provincial People's Hospital (East Region) from January 2011 to June 2014 were analyzed retrospectively. Inclusion criteria of this study were hospitalized neonates with complete clinical data, and the exclusion criteria were neonates without complete clinical data and automatic discharge. All of them were taken throat swab culture once during 24 hours after admission. The bacterial colonization, relationship between premature rupture of membranes (PROM) and neonatal infection, relationship between preterm and full-term neonates and infection were detected. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Sichuan Provincial People's Hospital (East Region). Results ① Four hundreds and eight-seven samples (52.1%) showed normal mixed bacteria, 259 samples (27.7%) were pathogenic bacteria, another 188 samples (20.1%) were negative in 934 throat swab culture results from 2011 to 2014. Top 5 pathogenic bacteria were Staphylococcus epidermidis (43 strains, 16.6%), Hemophilus parainfluenzae (26 strains, 10.0%), Hemophilus influenzae (21 strains, 10.0%), Pneumonia kleiber (21 strains, 8.1%) and Escherichia coli (19 strains, 7.3%) in 4 years. ②There was statistical significance between respiratory tract infection rates in neonates with PROM (96.7%) and non-PROM cases (85.6%) (χ2=5.692, P=0.013). Throat swab culture positive in neonates with PROM>24 hours (70.0%) was higher than that in non-PROM term (50.7%), which had statistical significance (χ2=6.685, P=0.013). ③ Ninety-two cases(55.8%) who received throat swab culture showed positive in premature infants, and 654 cases (85.0%) showed positive in full-term infants. The positive rate of throat swab culture and positive rate of throat swab culture combined with infection of full-term neonates were higher than those of preterm neonates (85.0% vs 55.8%, 53.5% vs 37.0%), which had significant differences (χ2=72.453, 8.855; P<0.05). Besides, there was statistical significance between premature and full-term infants in throat swab culture comparing mixed and single bacteria test (χ2=16.975, 55.107; P<0.001). Conclusions Throat swab culture can be useful in identifying bacterial colonization during 24 hours after admission, especially for those with PROM. Key words: Throat swab culture; Bacteria; Bacterial colonization; Infant, newborn