In vitro activity of quinupristin/dalfopristin against selected bacterial pathogens isolated in Italy.

OBJECTIVE

To evaluate the activity of quinupristin/dalfopristin, a new injectable streptogramin, against 732 clinical strains recently isolated in Italy.

METHODS

Susceptibility tests were performed according to NCCLS-guided MIC methodology. Pathogens included in the evaluation included 108 Staphylococcus aureus isolates, 124 coagulase-negative staphylococcal isolates, 158 Streptococcus pyogenes isolates, 30 Streptococcus agalactiae isolates, 30 b-hemolytic streptococcal isolates, 18 Streptococcus sanguis isolates, 80 Streptococcus pneumoniae isolates, 69 Enterococcal isolates, 40 Haemophilus influenzae isolates, 30 Moraxella catarrhalis isolates and, finally, 30 Gram-positive and 25 Gram-negative anaerobes.

RESULTS

Quinupristin/dalfopristin inhibited Staphylococcus aureus and other Staphylococcus spp., irrespective of their oxacillin or erythromycin resistance phenotypes. Similarly, streptococci were fully inhibited by quinupristin/dalfopristin. Enterococcus faecalis was not included in the spectrum of this streptogramin, while isolates of Enterococcus faecium were inhibited by the new compound. Respiratory pathogens such as H. influenzae and M. catarrhalis were inhibited by quinupristin/dalfopristin as well as all Gram-negative anaerobes tested.

CONCLUSIONS

These findings suggest a putative role for quinupristin/dalfopristin in the empirical treatment of severe nosocomial and community-acquired infections caused by pathogens often displaying resistance to multiple antibiotics. This drug may provide an alternative to glycopeptide compounds.