Structural and mechanical properties of Klebsiella pneumoniae type 3 Fimbriae

This study investigated the structural and mechanical properties of Klebsiella pneumoniae type 3 fimbriae, which constitute a known virulence factor for the bacterium. Transmission electron microscopy and optical tweezers were used to understand the ability of the bacterium to survive flushes. An individual K. pneumoniae type 3 fimbria exhibited a helix-like structure with a pitch of 4.1 nm and a three-phase force-extension curve. The fimbria was first nonlinearly stretched with increasing force. Then, it started to uncoil and extended several micrometers at a fixed force of 66 ± 4 pN (n = 22). Finally, the extension of the fimbria shifted to the third phase, with a characteristic force of 102 ± 9 pN (n = 14) at the inflection point. Compared with the P fimbriae and type 1 fimbriae of uropathogenic Escherichia coli, K. pneumoniae type 3 fimbriae have a larger pitch in the helix-like structure and stronger uncoiling and characteristic forces.     

Fimbriae from the oral anaerobe Bacteroides gingivalis: physical, chemical, and immunological properties.

Circular dichroism spectra indicated the predominance of beta-sheet structure in Bacteroides gingivalis fimbriae regardless of the presence of sodium dodecyl sulfate. By using a computer program, the alpha-helix, beta-sheet, and beta-turn contents and the remainder were estimated to be 0, 55, 18, and 27%, respectively, judging from the circular dichroism spectra of the fimbriae. Heating for 5 min at 100 degrees C in sodium dodecyl sulfate was necessary to denature the fimbriae into their constituent protein (fimbrilin) monomers with a reduced content of beta-sheet structure. The amino-terminal amino acid sequence of the fimbrilin was different from partial or complete amino acid sequences of fimbrilins so far determined from Bacteroides nodosus, which falls into the same nonfermentative species of the genus Bacteroides as B. gingivalis, and from various other bacteria. Fimbrilin monomers had an isoelectric point of 6.0. Examination of antibodies against fimbriae and sodium dodecyl sulfate-denatured fimbrilin by enzyme-linked immunosorbent assay reinforced a previous notion (F. Yoshimura, K. Takahashi, Y. Nodasaka, and T. Suzuki, J. Bacteriol. 160:949-957, 1984) that different sets of antigenic determinants seemed to be exposed on their surfaces.     

Edwardsiella tarda in freshwater catfish and their environment.

Edwardsiella tarda was isolated from 47, 88, and 79% of skin, visceral, and dressed-fish samples, respectively. This species was also isolated from 30% of imported dressed fish, 75% of catfish pond water samples, 64% of catfish pond mud samples, and 100% of frogs, turtles, and crayfish from catfish ponds. The incidence of Edwardsiella increased during the summer months, as water temperatures increased. Of several isolation media evaluated, the most effective was selective enrichment in double-strength Salmonella-Shigella broth and subsequent plating on single-strength Samonella-Shigella agar. The significance of the incidence of Edwardsiella in catfish, catfish disease, and public health could not be substantiated.     

Immunochemical characterization of a haemagglutinating antigen of Arcobacter spp.

Abstract The Arcobacter haemagglutinin has been identified by Western immunoblot to be an immunogenic protein of about 20 kDa. The haemagglutinating activity is sensitive to proteolytic enzyme digestion and heat treatment of 80 °C and above. The Arcobacter haemagglutinin is possibly a lectin-like molecule binding to erythrocytes via a glycan receptor containing d-galactose as part of its structure.     

Biochemical characteristics of Edwardsiella ictaluri.

A total of 119 isolates of Edwardsiella ictaluri collected over the last 7 years from several states were biochemically characterized. Although not very reactive biochemically, this bacterium shows a high degree of homogeneity. Differences were found only in the production of gas from formate or from glucose at 37 degrees C and in the production of hydrogen sulfide as detected by lead acetate paper. Analysis of E. ictaluri by year of geographic area indicated that some differences existed, but no clear-cut biotypic variations were found. All isolates studied were capable of degrading chondroitin sulfate, a major component of cartilage, which may be an important virulence factor in the formation of the hole-in-the-head lesion characteristic of infected fish.     

Genetic studies to re-affiliate Edwardsiella tarda fish isolates to Edwardsiella piscicida and Edwardsiella anguillarum species

Until 2012, the genus Edwardsiella was composed by three species Edwardsiella tarda, Edwardsiella hoshinae and Edwardsiella ictaluri. In 2013, Edwardsiella piscicida, compiling fish pathogenic strains previously identified as E. tarda was described, and more recently a new species isolated from diseased eel was reported, namely Edwardsiella anguillarum.The incorporation of these species into the genus makes necessary a revision of the taxonomic position of the isolates previously identified as E. tarda. Using AFLP technique, MLSA studies and in silico DNA–DNA hybridization, 46 of 49 E. tarda isolates were re-assigned as E. piscicida and 2 as E. anguillarum, whereas it was confirmed previous classification of the Edwardsiella types and reference strains used. The study of the taxonomic resolution of the genes 16S rRNA, adk, atpD, dnaJ, glnA, hsp60, tuf as well as the possible combinations among housekeeping genes, showed that the gene dnaJ was the more resolutive. In conclusion, the use of molecular techniques is necessary to accurately identify Edwardsiella isolates, especially when differentiating new species from E. tarda.     

Plasmid and serological differences between Edwardsiella ictaluri strains.

Several studies have shown that isolates of Edwardsiella ictaluri obtained from infected channel catfish in the southeastern United States harbor two cryptic plasmids, designated pCL1 (5.7 kb) and pCL2 (4.9 kb). These isolates appear to be serologically homogeneous. To extend these studies, we focused our analyses on two isolates of nonictalurid origin. Plasmid analyses of a danio isolate showed that it harbored plasmids which were similar if not identical to pCL1 and pCL2. This strain was also serologically indistinguishable from those isolated from channel catfish. In contrast, a green knife fish (GNF) isolate harbored four plasmids with relative mobilities of 6.0, 5.7, 4.1, and 3.1 kb. Southern blot analyses indicated that only the 5.7- and 4.1-kb plasmids strongly hybridized under high-stringency conditions to probes specific for pCL1 and pCL2, respectively. The GNF isolate showed minimal reactivity when reacted with polyclonal antiserum prepared against a channel catfish isolate. However, polyclonal antiserum to the GNF isolate strongly reacted with the GNF isolate in both surface fluorescence and agglutination reactions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses of cell lysates showed that the protein banding patterns of the strains compared were similar. However, Western blots of proteinase K-digested cell extracts showed that O antigen of the GNF isolate was antigenically distinct from the O antigen of the other isolates. These studies indicate that there are different serotypes of E. ictaluri and suggest that plasmid and serological analyses of future isolates of E. ictaluri can be used to determine whether structurally distinct strains are emerging in major channel catfish aquaculture areas.     

Fimbriae and Haemagglutinins in Erwinias of the Carotovora Group

1. Thirteen Erwinia carotovora strains produced mannose-sensitive haemagglutinins associated with the presence of type-1 fimbriae.
2. Three fimbriate Er. rhapontici strains produced haemagglutinins of the mannose-resistant and eluting (MRE) type.
3. There were 12 Er. carotovora , 12 Er. atroseptica and 2 Er. chrysanthemi strains that produced no detectable haemagglutinins and were non-fimbriate.     

Plasmid homologies in Edwardsiella ictaluri

Plasmids from all available non-channel catfish isolates of Edwardsiella ictaluri were classified by gel electrophoresis and hybridization methods. All isolates, regardless of source, contained classes of homologous plasmids with similar but not identical sizes.     

Fimbriae of Escherichia coli K-12 strain AW405 and related bacteria.

Fimbriate strains of Escherichia coli K-12 of the AW405 series agglutinated erythrocytes of several animal species. The hemagglutination was mannose senstivie, and the fimbriae were type 1. When cultured for extended periods in static broths, they did not form fimbrial pellicles but formed thick, nonfimbrial pellicles, the appearance of which was not associated with the selective outgrowth of fimbriate-phase bacteria.     

Oral Fimbriae and Papillae in Parasitic Lampreys (Petromyzontiformes)

There are 38 species of living lampreys, 18 parasitic and 20 nonparasitic. The parasitic species feed as adults, while the nonparasitic do not. The taxonomy and systematics of the living lampreys is based primarily on dentition characters. Since the number of oral fimbriae and oral papillae have never been systematically investigated in lampreys, we compared them in 17 of the 18 parasitic lampreys to assess their usefulness as taxonomic characters. Both showed little variation with total length and sex within a species, while exhibiting greater variation between species. Parasitic species belonging to the three lamprey families could be distinguished using the number of oral fimbriae: southern hemisphere Mordaciidae (0) and Geotriidae (55–65) and northern hemisphere Petromyzontidae (81–144). However, the taxonomic usefulness of the two characters at the species level was limited. Ten out of the 17 species of parasitic lampreys were placed into four distinct groups based on their numbers of oral fimbriae, and only in two of these was the character diagnostic. Twelve out of the 17 species were placed into two distinct groups based on their numbers of oral papillae and for none of these was the character diagnostic. Blood feeders and intermediate feeders (blood + flesh) were shown to have significantly higher numbers of oral fimbriae than flesh feeders. The higher numbers of oral fimbriae in the former two types of feeders were presumed to be linked to their greater need to create a good seal for feeding purposes. Blood feeders were also shown to have significantly higher numbers of oral papillae than either intermediates or flesh feeders. The higher numbers of oral papillae in the blood feeders were presumed to be linked to their greater need to find suitable attachment sites for feeding purposes.     

Edwardsiella tarda in freshwater catfish and their environment

Edwardsiella tarda was isolated from 47, 88, and 79% of skin, visceral, and dressed-fish samples, respectively. This species was also isolated from 30% of imported dressed fish, 75% of catfish pond water samples, 64% of catfish pond mud samples, and 100% of frogs, turtles, and crayfish from catfish ponds. The incidence of Edwardsiella increased during the summer months, as water temperatures increased. Of several isolation media evaluated, the most effective was selective enrichment in double-strength Salmonella-Shigella broth and subsequent plating on single-strength Samonella-Shigella agar. The significance of the incidence of Edwardsiella in catfish, catfish disease, and public health could not be substantiated.     

Haemagglutinins and Fimbriae in Different Serotypes and Biotypes of Yersinia enterocolitica

When cultured in static broth at 20°C, 46 of 115 strains of Yersinia enterocolitica , diverse in biotype and serotype, produced a broad-spectrum mannose-resistant (MR) adhesin that agglutinated the erythrocytes of all of 10 animal species examined. The production of haemagglutinin (HA) was associated with the presence of fimbriae of S nm diameter. Culture of HA+ strains at 37° resulted in the disappearance of haemagglutinating ability and loss of fimbrial production. Strains of Y. enterocolitica with K1 antigen produced an MR adhesin that agglutinated only fowl erythrocytes and was associated with fimbriae of 4–4.5 nm diameter. None of 14 strains of Y. pseudotuberculosis was haemagglutinating.     

Expression of Fimbriae and Host Response in Branhamella catarrhalis Respiratory Infections

Sputum during the acute exacerbation of chronic respiratory diseases were observed under the electron microscope, to determine the in vivo expression of surface structures of Branhamella catarrhalis (B. catarrhalis), the polymorphonuclear neutrophil (PMN) response to B. catarrhalis infections, and the composition of sputum. It was found that during infection fimbriae are expressed in B. catarrhalis. However, there were sparsely to densely fimbriated bacteria in each sputum sample. The length of the fimbriae were from 50 to 76 nm. In the sparsely fimbriated B. catarrhalis, external to the cell wall, a thin, granular, electron-dense layer was observed. Due to the presence of fimbriae, this layer was not seen in densely fimbriated B. catarrhalis. Blebs were also found in B. catarrhalis. PMNs were found to phagocytose both B. catarrhalis and debris. Evidence was found that debris were formed mainly by the destruction of PMNs. Bacteria as well as debris were phagocytosed by PMNs.