Sodium Channel Blocking Activity in Coliforms

Abstract

Necrotizing enterocolitis (NEC) is a devastating disease that mainly affects low birth-weight, preterm neonates. The disease is characterized by necrotizing injury to the intestine that requires antibiotic treatment and, in severe cases, surgical intervention. The exact etiology of the disease remains unclear but current evidence has shown that bacteria play a pivotal role in the development of NEC. Bacteria of the family Enterobacteriaceae are the most commonly described bacteria found in association with NEC. Recently, Sevcik et al. (2003) documented saxitoxin (STX) producing Enterobacter sp. and Klebsiella pneumoniae in cows that have bovine paralytic syndrome (BPS). These bacteria are also commonly isolated from neonates that develop NEC. The aim of this study was to test the hypothesis that STX producing bacteria would be more common in NEC infants, because paralysis of the vagus nerve would result in bacterial overgrowth and subsequent translocation across the epithelium. Enterobacteriaceae isolates from NEC, suspected NEC and healthy infants were tested for STX production using mouse neuroblastoma viability and fluorescence assays. A Bacillus fluorescent assay was also developed that allowed more rapid throughput of samples. Out of fifty neonates bacterial isolate tested six were found positive for sodium channel blocking activity. Two bacterial isolate were from NEC neonates and this in part supports the hypothesis. However, these bacteria were also isolated from a control neonate. This is the first time sodium channel blocking activity has been detected in bacteria of human origin. The nature of the sodium channel blocking agent(s) remains unknown at this time.