Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have ...

Fimbriae have been shown to play an essential role in the adhesion of pathogenic gram-negative bacteria to host cells. In the enteroinvasive bacterium Yersinia pseudotuberculosis, we characterized a previously unknown 11-kb chromosomal locus involved in the synthesis of type IV pili. The locus consists of 11 open reading frames forming a polycistronic unit and encoding putative Pil proteins, Pi...

Streptococcus agalactiae, also referred to as Group B Streptococcus (GBS), is one of the most common causes of life-threatening bacterial infections in infants. In recent years cell surface pili have been identified in several Gram-positive bacteria, including GBS, as important virulence factors and promising vaccine candidates. In GBS, three structurally distinct types of pili have been discov...

Although there is substantial evidence that type IV pili purified from diarrhea-associated Aeromonas species (designated Bfp for bundle-forming pilus) are intestinal colonization factors (S. M. Kirov, L. A. O'Donovan, and K. Sanderson, Infect. Immun. 67:5447-5454, 1999), nothing is known regarding the function of a second family of Aeromonas type IV pili (designated Tap for type IV Aeromonas pi...

The PapC usher is a β-barrel outer membrane protein essential for assembly and secretion of P pili that are required for adhesion of pathogenic E. coli, which cause the development of pyelonephritis. Multiple protein subunits form the P pilus, the highly specific assembly of which is coordinated by the usher. Despite a wealth of structural knowledge, how the usher catalyzes subunit polymerizati...

The opportunistic pathogen Pseudomonas aeruginosa produces multifunctional, polar, filamentous appendages termed type IV pili. Type IV pili are involved in colonization during infection, twitching motility, biofilm formation, bacteriophage infection, and natural transformation. Electrostatic surface analysis of modeled pilus fibers generated from P. aeruginosa strain PAK, K122-4, and KB-7 pilin...

H10407 is a strain of enterotoxigenic Escherichia coli (ETEC) that utilizes CFA/I pili to adhere to surfaces of the small intestine, where it elaborates toxins that cause profuse watery diarrhea in humans. Expression of the CFA/I pilus is positively regulated at the level of transcription by CfaD, a member of the AraC/XylS family. DNase I footprinting revealed that the activator has two binding...

The bundle-forming pili (BFP) of enteropathogenic Escherichia coli are believed to play a role in pathogenesis by causing the formation of bacterial microcolonies that bind epithelial surfaces of the small intestine. This in vivo process is mimicked in vitro by the autoaggregation and localized adherence phenotypes. Expression of BFP, a member of the type IV pilus family, requires the enteroadh...

F plasmid derivatives carrying kan insertion mutations in the transfer region genes traR, trbJ, and trbH were constructed. Standard tests indicated that these loci are not essential for F pilus production or F transfer among Escherichia coli K-12 hosts. Among the traR and trbH mutants tested, the orientation of the kan cassette had no effect on the mutant phenotype. In each case, there was no s...

The bacterial species Vibrio cholerae includes harmless aquatic strains as well as strains capable of causing epidemics and global pandemics of cholera. While investigating the relationship between pathogenic and nonpathogenic strains, we identified a chromosomal pathogenicity island (PAI) that is present in epidemic and pandemic strains but absent from nonpathogenic strains. Initially, two Tox...