Two novel synthetic peptides inhibit quorum sensing-dependent biofilm formation and some virulence factors in Pseudomonas aeruginosa PAO1.

Quorum sensing (QS) regulates virulence factor expression in Pseudomonas aeruginosa. Inhibiting the QS-controlled virulence factors without inhibiting the growth of P. aeruginosa is a promising approach for overcoming the widespread resistance of P.

Synthesis and biological evaluation of new thiazolopyrimidines.

In this study, a series of 4-amino-5-cyano-3-substituted-2,3-dihydrothiazol-2-thiones (1a-c), as well as their triazolo and triazinopyrimidine derivatives such as 8-substituted-3-benzyl-5-methylthiazolo[5,4-e][1,2,4] triazolo[1,5-c]pyrimidin-2-thiones (4-6, 10) and 3-benzyl-5-methyl thiazolo[5,4-e]pyrimidino[3,4-b][1,2,4]triazin-2-thiones (7a-b) were prepared as potential antimicrobial and antitumor agents. Some of the tested compounds showed promising antimicrobial activity and non of them showed any appreciable antitumor activity.

Synthesis and antimicrobial activity of some new 2-indolinone derived oximes and spiro-isoxazolines.

The synthesis and spectral analysis of some new 1,3-dihydro-3-hydroxy-3-[2-hydroxyimino-2-(substituted phenyl)ethyl]-2H-indol-2-ones (21-32) and spiro[3H-indol-3,5'-(4'H)-isoxazol]-2(1H)-ones (33-44) are described. Sixteen of the synthesized compounds were screened in vitro for their growth inhibitory activity against thirteen species of microorganisms, viz, S. aureus, S.

Modulation of biofilms of Pseudomonas aeruginosa by quinolones.

The interaction between four fluoroquinolones (ciprofloxacin, norfloxacin, pefloxacin, and ofloxacin) and biofilms of Pseudomonas aeruginosa in wells of microtiter plates and on segments of vascular catheters were studied in an in vitro model of vascular catheter colonization. Subinhibitory concentrations (one-half, one-fourth, and one-eight of the MIC) of the fluoroquinolones reduced the adherence of P. aeruginosa to 30 to 33, 44 to 47, and 61 to 67% of that of controls, respectively.

Relationships between beta-lactamase production and beta-lactam susceptibility of environmental strains of Yersinia kristensenii.

Strains of Yersinia kristensenii display high susceptibility to carbenicillin (MIC90 less than 8 micrograms/ml) in comparison with the majority of environmental strains of Yersinia closely related to Y. enterocolitica which are resistant to this antibiotic (MIC90 greater than 256 micrograms/ml). beta-lactamases of 39 strains of Y.

Antimicrobial susceptibilities of food-isolated strains of Yersinia enterocolitica, Y. intermedia, Y. frederiksenii, and Y. kristensenii.

The in vitro antimicrobial susceptibility of Yersinia enterocolitica and newly related species isolated from foods was examined. Only 4 of 375 isolates displayed resistance to non-ss-lactam antibiotics. MICs of ampicillin and carbenicillin determined by agar dilution with respect to 125 isolates showed the high susceptibility of Y.