Activity of quinolones against viridans group streptococci isolated from blood cultures of patients with haematological malignancy

Use of fluoroquinolones for antimicrobial prophylaxis during neutropenia is often cited as a significant predisposing factor for viridans group strept ococcus (VGS) bacteraemia. Newer compounds in this class are reputed to hav e enhanced activity against Gram-positive bacteria, and we determined the m inimal inhibitory concentrations (VGS) for ciprofloxacin and three of the n ewer compounds: trovafloxacin, fleroxacin and clinafloxacin, against 44 iso lates of VGS. On a gravimetric basis, clinafloxacin was most active (MIC90 0.19 mg/l), whereas ciprofloxacin and fleroxacin were the least active (bot h MIC90 16 mg/l). Clinafloxacin warrants further study as an agent of proph ylaxis against bacterial infection in neutropenic patients.