Effect of salicylate on expression of flagella by Escherichia coli and Proteus, Providencia, and Pseudomonas spp.

Osmotic stress, salicylate, and Mar (multiple antibiotic resistance) mutation are known to block the expression of the OmpF porin. Since these conditions have also been shown to inhibit the expression of P and CFA fimbriae in Escherichia coli, we speculated that they might affect the expression of flagella as well. Hyperosmotic conditions have been shown to block the synthesis of flagellin and expression of flagella in E. coli (C. Li, C. J. Louise, W. Shi, and J. Adler, J. Bacteriol. 175:2229-2235, 1993). In the current study, sodium salicylate was found to inhibit the motility of E. coli, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, and Providencia stuartii in a reversible, concentration-dependent manner. Swarming did not occur at 20 mM sodium salicylate. Salicylate also blocked the synthesis of flagellin in E. coli. Phenotypic Mar mutants of E. coli derived from motile strains were amotile. Flagella were markedly reduced as determined by scanning electron microscopy when P. mirabilis was grown in broth containing 20 mM salicylate. Salicylate had no apparent effect, however, on expression of a 40-kDa porin protein in P. mirabilis. This finding suggests that the noted effect of salicylate on Proteus spp. may be mediated through a mechanism other than porin production or that the Proteus porin may not be analogous to OmpF in E. coli. Salicylate decreased the motility of Pseudomonas cepacia but had no effect on Pseudomonas aeruginosa. The exact mechanism by which salicylate exerts its effect is not known, but it appears to be related to osmoregulation.

The haemagglutinins and fimbriae of Proteus penneri.

The haemagglutinins and fimbriae produced by 18 strains of Proteus penneri were studied and compared with those formed by representative strains of other species of Proteeae. After repeated subcultures at 30 degrees C, 12 P. penneri strains formed only MR/K haemagglutinins which were associated with thin, non-channelled, type-3 fimbriae. Two strains formed simultaneously both MS and MR/K haemagglutinins associated with thick, channelled, type-1 fimbriae and type-3 fimbriae, respectively. Four strains formed simultaneously both MR/K and MR/P haemagglutinins. No P. penneri strain formed either MS or MR/P haemagglutinins alone under these conditions. The type-3 fimbriae from P. penneri strain E180 were isolated, purified and found to be protein of 19 Kda. Immunoelectronmicroscopy studies with antibody to the type-3 fimbriae of strain E180 showed that P. penneri strains at least two antigenic types of type-3 fimbriae. The type-3 fimbrial antigen of the vaccine strain E180 was shared by another eight strains of P. penneri. A further eight P. penneri strains and the strains representative of other genera within Proteeae had type-3 fimbriae of a different antigenic type. The formation of these haemagglutinins and fimbriae suggests that this organism is well endowed to be a urinary-tract pathogen.

[Morphological properties and adhesiveness of bacteria of the genus Proteus]. / Morfologicheskie svoistva i adgezivnost' bakterii roda Proteus.

Out of 100 Proteus strains isolated from patients with purulent inflammatory, urological and enteric diseases, from healthy persons and from the environment, 29 stains showed the positive D-mannose-resistant reaction of hemagglutination with chick red blood cells and 18 strains showed such reaction with goose and duck red blood cells. The results of these studies permit the use of chick red blood cells as target cells for the detection of Proteus adhesin. Human red blood cells of groups O, A, B and AB, sheep, bovine, dog, rat and rabbit red blood cells gave no positive D-mannose-sensitive reaction and D-mannose-resistant reaction of hemagglutination. In bacterial cells pili function as organelles which determine Proteus adhesiveness, while flagellae play no positive role.

Fractionation of the Providencia stuartii cell envelope.

Cell envelopes (i.e. unfractionated inner and outer membranes) were obtained from Providencia stuartii by following procedures previously applied to the isolation of envelopes from Escherichia coli. The P. stuartii envelopes contained known inner membrane enzymes that included a variety of dehydrogenases and ATPase. The catalytic activity of the ATPase depended upon the concentration of magnesium ions, the substrate (ATP) level and the ratio of magnesium ions to ATP. Cell envelopes from P. stuartii were further fractionated to recover inner and outer membrane polypeptides by treatment with the detergent Sarkosyl. Proteins from the periplasmic region were recovered by a simple osmotic shock procedure also previously applied to E. coli. The purity of the various P. stuartii cell envelope fractions was assessed by a combination of techniques that included one- and two-dimensional gel electrophoresis of proteins, enzyme assays and detection of penicillin-binding proteins.

Hemagglutinins and fimbriae of Providencia spp.

A series of 25 strains of Providencia spp. produced at least five different patterns of hemagglutination as judged by results from hemagglutination tests in the presence and absence of D-mannose and at least six distinct types of fimbriae as seen from observations with the electron microscope.

Mobilization of the Proteus morganii chromosome by R plasmids.

R plasmids R702, R711b, R1, D, Rip69, R447b, R471 and R394, belonging to different incompatibility groups, mobilized the Proteus morganii 2815 chromosome. Matings employing plasmids R711b or R702 as sex factors with doubly auxotrophic recipients produced recombinants characterized by the obligatory inheritance of ser-1+, irrespective of the selected marker.

Correlation of the characters fermentation of trehalose, non-transmissible resistance to tetracycline, and relatively long flagellar wavelength in Proteus morganii.

An investigation of strains of Proteus morganii isolated from patients in Odense, Denmark, and of 21 serotype strains revealed a close correlation between the fermentation of trehalose and a non-transmissible resistance to tetracycline. The trehalose fermenting, tetracycline resistant strains had a longer flagellar wavelength than the non-fermenting, sensitive strains. Resistance to chloramphenicol occurred only in strains of the former group.

[Effect of pH on bacteria in early log phase]. / Influence du pH sur des bactéries en phase de croissance

The bacteria harvested in the early log phase lyse when they are submitted to a pH above 10. The peptidoglycan is not degraded in these conditions. Thus, the authors used these properties to extract the peptidoglycan from several gram negative and gram positive bacteria.