Susceptibility of 4410 clinical isolates to doxycycline

In an 1100-bed hospital where doxycycline has been widely used, the susceptibility to doxycycline of 4410 clinical isolates was examined. Ninety-one and 80.8 per cent of the Staphylococcus aureus and Haemophilus influenzae strains, respectively, were susceptible to 1 mg doxycycline/l. Seventy-four per cent of the Escherichia coli and 81.7 per cent of the Klebsiella strains were inhibited by 4 mg/l. The Enterobacter and Enterococcus strains were less susceptible. Nearly all Proteus mirabilis isolates were resistant. The results are comparable to those of other studies.