ABSTRACT
Group B Streptococcus (GBS) is a major causative agent of neonatal meningitis due to its ability to efficiently cross the blood-brain barrier (BBB) and enter the central nervous system (CNS). It has been demonstrated that GBS can invade human brain microvascular endothelial cells (hBMEC), a primary component of the BBB; however, the mechanism of intracellular survival and trafficking is unclear. We previously identified a two component regulatory system, CiaR/H, which promotes GBS intracellular survival in hBMEC. Here we show that a GBS strain deficient in the response regulator, CiaR, localized more frequently with Rab5, Rab7 and LAMP1 positive vesicles. Further, lysosomes isolated from hBMEC contained fewer viable bacteria following initial infection with the ΔciaR mutant compared to the WT strain. To characterize the contribution of CiaR-regulated genes, we constructed isogenic mutant strains lacking the two most down-regulated genes in the CiaR-deficient mutant, SAN_2180 and SAN_0039. These genes contributed to bacterial uptake and intracellular survival. Furthermore, competition experiments in mice showed that WT GBS had a significant survival advantage over the Δ2180 and Δ0039 mutants in the bloodstream and brain.
Subject(s)
Bacterial Adhesion/immunology , Bacterial Proteins/genetics , Brain/immunology , Endothelium, Vascular/immunology , Protein Kinases/metabolism , Streptococcal Infections/microbiology , Streptococcus agalactiae/pathogenicity , Virulence/immunology , Animals , Bacterial Proteins/metabolism , Biological Transport , Blood-Brain Barrier , Brain/metabolism , Brain/microbiology , Brain/pathology , Cell Movement , Cells, Cultured , Endothelium, Vascular/metabolism , Endothelium, Vascular/microbiology , Endothelium, Vascular/pathology , Fluorescent Antibody Technique , Gene Expression Regulation, Bacterial/genetics , Genes, Regulator , Humans , Immunity, Innate/immunology , Male , Mice , Mutation/genetics , Protein Kinases/genetics , Streptococcal Infections/genetics , Streptococcal Infections/immunology , Virulence/geneticsABSTRACT
AIMS: The aim of this study was to evaluate the potential role of laparoscopic appendicectomy in reducing morbidity and length of stay in children compared to open procedures in a UK District General Hospital setting. METHODS: A three-year retrospective review of children ≤ 15 years with histologically confirmed appendicitis who underwent laparoscopic (LA) and/or open (OA) appendicectomy was performed. Choice of operation was based on individual surgeon's preference and on patient's body size. Data collected included rate of histologically complicated appendicitis, post-operative length of stay (LOS), and collective and differential morbidity rates, i.e., wound infection, intra-abdominal collection, and ileus. Chi-square and Mann-Whitney tests were used for statistical analysis. P<0.05 was regarded as significant. RESULTS: Eighty children (70% male) were identified at median age 11 (3-15) years. They could be divided into complicated (n=18, 22%) and simple appendicitis (n=62, 78%). Appendicectomy was performed in all as an OPEN (n=53, 66%) or LAPAROSCOPIC (n=27, 34%) procedure. Both groups were comparable in gender distribution (P=0.11) and rate of complicated appendicitis (30% vs. 19%, respectively; P=0.27). Median age was significantly lower in the OPEN group [10 (3-15) vs. 12 (7-15) years; P<0.004]. Laparoscopic appendicectomy had a significantly lower rate of collective morbidity (3.8% vs. 25.9%; P<0.003), including lower rate of intra-abdominal collection (1.9% vs. 14.8%; P<0.01). Median LOS was not significantly different (1 day vs. 2 days; P=0.14). CONCLUSION: Laparoscopic appendicectomy in children in a UK District General Hospital is safe and was associated with significantly less post-operative morbidity than the open technique.
