DETECTION AND MOLECULAR SEROTYPING OF GROUP B STREPTOCOCCUS IN FATAL NEONATAL PNEUMONIA IN CHINA

Abstract

INTRODUCTION: Group B Streptococcus (GBS) has been recognized as an important pathogen in neonatal infectious disease. However, there are few data on the prevalence of neonatal GBS infection in China. OBJECTIVE: Our aim was to estimate the infection rate of GBS in neonatal pneumonia in China and identify distribution of the GBS serotype. METHODS: We retrospectively studied 200 children with fatal neonatal pneumonia who died between 1953 and 2004; 34 fatal neonatal cases without any infectious disease were used as a control group. Paraffin-embedded lung tissues were collected for total genomic DNA extraction. Polymerase chain reaction (PCR) and Southern blotting were used for GBS detection and molecular serotyping. RESULTS: (1) The positive rate of GBS in the pneumonia group was significantly higher than that in the control group (PCR: 26% vs 3% [P < .01]; Southern blot: 65% vs 18% [P < .01]). (2) The positive rate in neonates younger than 7 days was significantly higher than that in neonates older than 7 days (PCR: 37% vs 13% [P < .01]; Southern blot: 72% vs 52% [P < .05]). (3) Risk factors were identifiable for most GBS-positive cases. (4) In the pneumonia group, 22 GBS-positive cases were serotypeable: 7 cases were identified as serotype Ia, 6 cases were serotype III, 5 cases were serotype II, and 1 case was serotype Ib. CONCLUSIONS: In China, GBS is an important pathogen in fatal neonatal pneumonia, especially in early-onset cases. Serotypes Ia, III, and II were the most common serotypes identified.