acriflavine and Bacterial-Infections

98 Lactococcus lactis strains were isolated from traditional fermented milk products in Turkey tested against 60 lactococcal lytic phages to determine their resistance levels. While 82 L. lactis strains were sensitive against lactic phages at different levels, 16 L. lactis strains showed resistance to all phages tested. Types of phage resistance among 16 L. lactis strains were identified as phage adsorption inhibition in eight strains, restriction/modification in six strains and abortive infection (heat sensitive phage resistance) in two strains, using three broad-spectrum phages phi pll 98-32, phi pld 67-42 and phi pld 67-44.

Topics: Acriflavine; Adsorption; Animals; Bacterial Infections; Bacterial Proteins; Bacteriophages; Biochemistry; Cell Proliferation; Cloning, Molecular; Fermentation; Lactococcus lactis; Milk; Plasmids; Restriction Mapping; Temperature

Autoagglutination (AA phenotype) of mesophilic aeromonads in broth was found to be a virulence-associated marker. There were two kinds of AA+ strains: those that spontaneously pelleted (SP+), and those that pelleted only after boiling (PAB+). Of 79 strains tested, 24 (30%) were AA+, and 18 of these were recovered from clinical specimens. Most of the AA+ strains (n = 21) were identified as either Aeromonas sobria or Aeromonas hydrophila. Of the well-documented clinical isolates of A. sobria and A. hydrophila available, 5 (46%) of 11 from invasive disease and 4 (14%) of 29 from noninvasive disease were SP- PAB+. The SP- PAB+ phenotype was significantly associated with invasive infections (e.g., bacteremia and peritonitis [chi 2, P less than 0.05]). All seven of the SP- PAB+ A. sobria and A. hydrophila strains tested killed mice within 48 h after intraperitoneal infection with 1 x 10(7) to 3 x 10(7) CFU, whereas only two of four SP+ PAB+ strains tested were lethal. All of the SP- PAB+ A. sobria and A. hydrophila isolates examined shared common O somatic antigens and possessed an external layer peripheral to the cell wall as determined by thin-section electron micrography. The LL1 strain of A. hydrophila used by Dooley et al. (J. S. G. Dooley, R. Lallier, and T. J. Trust, Vet. Immunol. Immunopathol. 12:339-344, 1986) to demonstrate an S membrane protein component in aeromonads virulent for fish also was SP- PAB+ and possessed the peripheral membrane, suggesting an association between these two components. Seven AA- and three SP+ strains tested lacked this layer; furthermore, 22 (71%) of 31 such isolates did not kill mice. The AA phenotype was a stable characteristic upon long-term passage of isolates in vitro. Study of SP+ and PAB+ aeromonads by surface charge and hydrophobicity analyses indicated that neither property correlated with either virulence or the presence of an external layer.

Topics: Acriflavine; Aeromonas; Agglutination; Animals; Bacterial Infections; Detergents; Humans; Hydrogen-Ion Concentration; Mice; Microscopy, Electron; Salts; Solubility; Surface Properties

Motile Aeromonas isolated from fish were studied for their virulence in fish in relation to some surface characteristics. The results showed that only the most virulent strains of A. hydrophila used in this study shared a common O antigen, did not agglutinate in acriflavine, settled down after boiling, and were resistant to the bactericidal action of fresh normal mammalian serum. The least virulent strains could not be grouped into this O antigenic group, they did not settle after boiling, and were sensitive to the bactericidal effect of serum. It is suggested that agglutination in acriflavine, stability after boiling, and sensitivity to normal fresh serum could be used for screening the Aeromonas isolates for virulence in fish.

Topics: Acriflavine; Aeromonas; Animals; Antigens, Bacterial; Bacterial Infections; Blood Bactericidal Activity; Fish Diseases; Hot Temperature; Salmonidae; Serotyping; Trout

Topics: Acridines; Acriflavine; Anti-Bacterial Agents; Bacterial Infections; Drug Resistance, Microbial; Enterobacter; Enterobacteriaceae; Escherichia coli; Humans; Proteus; R Factors; Trimethoprim