BACKGROUND Cholera toxin (CT) and toxin-co-regulated pili (TCP) are the major virulence factors of Vibrio cholerae O1 and O139 strains that contribute to the pathogenesis of disease during devastating cholera pandemics. However, CT and TCP negative V. cholerae strains are still able to cause severe diarrheal disease in humans through mechanisms that are not well understood. METHODOLOGY/PRINCI...

The toxin HlyA is exported from Escherichia coli, without a periplasmic intermediate, by a type I system comprising an energized inner-membrane (IM) translocase of two proteins, HlyD and the traffic ATPase HlyB, and the outer-membrane (OM) porin-like TolC. These and the toxin substrate were expressed separately to reconstitute export and, via affinity tags on the IM proteins, cross-linked in vi...

Several genes involved in the lipopolysaccharide (LPS) biosynthetic pathway have been shown to affect the expression or activity of Escherichia coli hemolysin (Hly), a secreted cytotoxin that is the prototype of the RTX family of toxins. To further study this relationship, E. coli K-12 strains harboring mutations in the LPS biosynthetic genes rfaS, rfaQ, rfaJ, rfaP, and rfaC were transformed wi...

BACKGROUND Uropathogenic Escherichia coli O- Serogroups with their virulence factors are the most prevalent causes of UTIs. OBJECTIVES The present investigation was performed to study the virulence factors and O-Serogroups profiles of UPEC isolated from Iranian pediatric patients. PATIENTS AND METHODS This cross sectional investigation was performed on 100 urine samples collected from hospi...

The hemolytic phenotype in Escherichia coli is determined by four genes. Two (hlyC and hlyA) determine the synthesis of a hemolytically active protein which is transported across the cytoplasmic membrane. The other two genes (hlyBa and hlyBb) encode two proteins which are located in the outer membrane and seem to form a specific transport system for hemolysin across the outer membrane. The prim...

PURPOSE To characterize the prevalence of hemolytic Shiga toxin-producing Escherichia coli (STEC) with a multidrug-resistant pattern in different age groups in Abeokuta, Nigeria. METHODS Nonrepetitive E. coli isolates were collected from 202 subjects with or without evidence of diarrhea. Each isolate was biochemically identified and antimicrobial susceptibility testing was performed using the...

A 5' nuclease assay has been developed to detect viable Listeria monocytogenes. The assay targets the hemolysin A (hlyA) transcript, which is found only in L. monocytogenes. The single-tube, reverse transcriptase (RT), fluorogenic probe-based assay was formatted by using Tth DNA polymerase whose activity was modulated by using the manganese-chelating morpholinepropanesulfonic acid (MOPS) buffer...

HlyU, a transcriptional regulator common in many Vibrio species, activates the hemolysin gene hlyA in Vibrio cholerae, the rtxA1 operon in Vibrio vulnificus and the genes of plp-vah1 and rtxACHBDE gene clusters in Vibrio anguillarum. The protein is also proposed to be a potential global virulence regulator for V. cholerae and V. vulnificus. Mechanisms of gene control by HlyU in V. vulnificus an...