In vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus derived from cystic fibrosis sputum.

We evaluated the in vitro activity of teicoplanin compared with vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) derived from cystic fibrosis (CF) sputum. Teicoplanin had a slightly lower median minimum inhibitory concentration (MIC) for these strains (0.25 micrograms/ml) than did vancomycin (0.5 micrograms/ml). Inoculum size increased the MICs similarly for both drugs, and pH variations did not significantly affect their activity. The presence of serum and sputum in the growth media decreased the activity of both drugs, although this was more pronounced for teicoplanin which is highly protein bound. We conclude that teicoplanin has activity against this pathogen and might be evaluated in clinical protocols designed to address this emerging clinical problem.

In vitro activity of sparfloxacin (AT-4140), a new quinolone agent, against invasive isolates from pediatric patients.

Sparfloxacin is a new oral fluoroquinolone agent with putative activity against common pediatric pathogens. Using the broth microdilution method, we evaluated sparfloxacin activity in comparison with those of other antimicrobial agents against 383 pediatric isolates derived from cultures of blood and other normally sterile body fluids. MICs were assessed in Mueller-Hinton broth, serum, and urine, as well as at inoculum sizes of 10(4) to 10(8) CFU/ml. The emergence and stability of resistance and cross-resistance of Pseudomonas aeruginosa (mucoid and nonmucoid) and Staphylococcus aureus to sparfloxacin and ciprofloxacin were evaluated. Inhibitory activity of sparfloxacin against most test organisms was within achievable serum levels. Sparfloxacin was greater than or equal to 2- to 4-fold more active than other quinolones against gram-positive pathogens and 2- to 4-fold less active than ciprofloxacin against P. aeruginosa. Sparfloxacin activity was unaffected by urine and was enhanced by two- to eightfold in human serum. Its potency was not affected by inocula of less than or equal to 10(7) CFU/ml. The frequency of development of spontaneous resistance was similar to that found for other new quinolone agents, and stable resistance emerged only in P. aeruginosa. Sparfloxacin merits additional study against invasive pediatric pathogens.