Risk factor assessment for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa in a community-based hospital.

A case-control study was performed in a community-based nonteaching hospital to assess patient risk factors for the acquisition of fluoroquinolone-resistant isolates of Pseudomonas aeruginosa. Fifty-five patients who were hospitalized between July 1, 1993 and December 31, 1993 and who had P. aeruginosa recovered from a clinical specimen were included in the analysis.

Virulence of coagulase-deficient mutants of Staphylococcus aureus in experimental endocarditis.

A sensitive rat endocarditis model which employed relatively small inocula (< or = 10(4) cfu) was used to examine the role of coagulase in the pathogenesis of infection. Rats with indwelling, intracardiac catheters were challenged intravenously with three strains of Staphylococcus aureus. The virulence of a coagulase-positive parental strain DU5808 was compared in terms of its ID50 for resected vegetations and catheters to that of two coagulase-negative mutant strains (DU5809 and DU5814) which had undergone site-specific mutagenesis.