ABSTRACT
The recent WHO report on antibiotic resistances shows a dramatic increase of microbial resistance against antibiotics. With only a few new antibiotics in the pipeline, a different drug delivery approach is urgently needed. We have obtained evidence demonstrating the effectiveness of a cell based drug delivery system that utilizes the innate immune system as targeting carrier for antibacterial drugs. In this study we show the efficient loading of neutrophil granulocytes with chlorhexidine and the complete killing of E. coli as well as Fusobacterium necrophorum in in-vitro studies. Fusobacterium necrophorum causes hepatic abscesses in cattle fed high grain diets. We also show in a mouse model that this delivery system targets infections of F. necrophorum in the liver and reduces the bacterial burden by an order of magnitude from approximately 2â¢106 to 1â¢105.
Subject(s)
Anti-Infective Agents, Local/administration & dosage , Cattle Diseases/therapy , Chlorhexidine/administration & dosage , Liver Abscess/veterinary , Micrococcus luteus/chemistry , Neutrophils/transplantation , Animals , Anti-Infective Agents, Local/therapeutic use , Cattle , Cattle Diseases/microbiology , Cell- and Tissue-Based Therapy/methods , Chlorhexidine/therapeutic use , Disease Models, Animal , Drug Delivery Systems/methods , Escherichia coli/drug effects , Fusobacterium necrophorum/drug effects , Liver Abscess/microbiology , Liver Abscess/therapy , Mice , Neutrophils/chemistry , Neutrophils/microbiologyABSTRACT
Fusobacterium necrophorum, a Gram-negative anaerobe, is the primary etiologic agent of liver abscesses in cattle. There are two subspecies; subsp. necrophorum and subsp. funduliforme, which differ in morphological, biochemical, molecular characteristics, and virulence. The subsp. necrophorum, which is more virulent, occurs more frequently in liver abscesses than the subsp. funduliforme. Bacterial adhesion to the host cell surface is critical to the pathogenesis of several bacterial infections, and in F. necrophorum, outer membrane proteins (OMP) have been shown to mediate adhesion to bovine endothelial cells. The objective of this study was to identify potential adhesins that are involved in adhesion of F. necrophorum subsp. necrophorum to the host cells. An OMP of 42.4 kDa, which binds with high affinity to the bovine endothelial cells and is recognized by the sera from cattle with liver abscesses, was identified. N-terminal sequencing of the protein showed 96% homology to the FomA protein of F. nucleatum. The PCR analysis showed that this fomA gene was present in several strains of subsp. necrophorum, subsp. funduliforme of bovine and subsp. funduliforme of human origin. The purified native and recombinantly expressed protein when preincubated with the endothelial cells, prevented the attachment of subsp. necrophorum significantly. In addition, the polyclonal antibody produced against the protein prevented the binding of subsp. necrophorum to bovine endothelial cells.
Subject(s)
Bacterial Adhesion , Bacterial Outer Membrane Proteins/metabolism , Endothelial Cells/microbiology , Fusobacterium Infections/microbiology , Fusobacterium necrophorum/metabolism , Animals , Bacterial Outer Membrane Proteins/genetics , Cattle , Cell Line , Fusobacterium necrophorum/genetics , Gene Expression Regulation, Bacterial , Humans , Protein Binding , VirulenceABSTRACT
A new splice variant of the Rett syndrome gene, MECP2, was recently identified, that includes coding sequence from exon 1, and is the predominant transcript in the central nervous system. This sequence encodes polyalanine and polyglycine stretches within the N-terminal portion of MeCP2, and may confer novel functional properties to the protein. We screened autism, mental retardation (MR), and control populations for sequence variation within this region, and identified variation in approximately 1% of MR cases screened (N = 1,410). No variants were identified in the autism sample (N = 401). Most of these variants occur within a trinucleotide repeat region and result in change in number of alanine or glycine residues within the repeat stretches. We suggest some of these variants may be a relatively frequent cause of non-specific MR or developmental delay.
