High rates of colonization and antimicrobial resistance of group B streptococcus highlight the need for vaccination even after implementation of guidelines for intrapartum antibiotic prophylaxis.

INTRODUCTION: It is estimated that about 11-35% of pregnant women are colonized with Group B streptococcus. Intrapartum antibiotic prophylaxis (IAP) is the primary intervention to decrease the risk of infecting babies born to GBS colonized mothers. METHODS: A total of 5,996 pregnant women, who received the Taiwanese universal GBS screening program from 2012 to 2020, were included in this study that investigated GBS colonization, antimicrobial resistance rates and their neonatal incidence of invasive GBS infection. RESULTS: The average GBS colonization rate was 18.5%. Older age groups had higher colonization rates than younger age groups. Compared to Taiwanese, immigrant women from Indonesia had a greater positive rate. GBS isolated from Vietnamese women had significant greater resistance to clindamycin relative to Taiwanese women. Rates of resistance to erythromycin increase from 35.5% to 45.5% over the 9 years of measurements. The incidence of invasive GBS disease was about 0.6/1,000 (4/6,204) live births during the study. CONCLUSIONS: Although relatively low incidence of invasive GBS diseases was observed after implementation of IAP, the colonization of GBS remains high and antimicrobial resistance of GBS is increasing. An effective GBS vaccine holds promise to be a solution for these issues.

Transgenic zebrafish eggs containing bactericidal peptide is a novel food supplement enhancing resistance to pathogenic infection of fish.

Zebrafish (Danio rerio) was used as a bioreactor to produce bovine lactoferricin (LFB), which has wide-ranging antimicrobial activity. We constructed an expression plasmid in which LFB was fused with green fluorescent protein (GFP) and driven by zebrafish beta-actin promoter. After microinjection, six transgenic founders were screened on the basis of GFP appearance. Among them, a stable ZBL-5 line was selected by the ubiquitous and strong expression of GFP. Using PCR and Western blot analysis, we confirmed that the recombinant LFB-GFP protein was produced by the F2 progeny derived from the ZBL-5 line. The bactericidal agar plate assay proved that the functional domain of LFB was released from the LFB-GFP fusion protein, resulting in strong bactericidal activity against Escherichia coli, Edwardsiella tarda and Aeromonas hydrophila. Furthermore, adult zebrafish were given one feeding of fifty 72-hpf transgenic embryos. The treated fish were then immersed in freshwater containing 1 x 10(5) CFU ml(-1)E. tarda for 7 days. The survival rate of the treated zebrafish was significantly higher than that of fish fed with fifty wild-type embryos (75 +/- 12.5% versus 4 +/- 7.2%). This line of evidence suggested that pathogen resistance can be enhanced by using transgenic embryos containing LFB-GFP as a food supplement for fish, while, at the same time, reducing the demand of chemical antibiotics.