In vitro antibacterial activity of a new quinolone drug for oral use, balofloxacin, and its clinical effects on respiratory infectious diseases

The antibacterial activity of a new quinolone drug for oral use, balofloxacin (BLFX), against fresh clinical isolates (between November 1992 and March 1993) was investigated. Sensitivities of Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pneumoniae to BLFX were distributed in the 0.1 ~1.56 μg/ml range, and the activity was more potent than that of ofloxacin (OFLX), by 2~4 times, and those of norfloxacin (NFLX) and enoxacin (ENX), by 4~8 times. BLFX exhibited activity against Haemophilus influenzae which was 4 times stronger than those of OFLX and ENX. Although the activity of BLFX against Klebsiella pneumoniae was inferior to those of OFLX and ENX, by 2~4 times, it was equivalent to that of NFLX. The clinical effects of BLFX on respiratory infectious diseases were investigated in 14 patients. The clinical efficacy was excellent in 4 and effective in 7, all of whom showed improvement in infectious symptoms. In 5 patients with pneumonia, including one with mycoplasma pneumonia and 2 with acute bronchitis particularly, the symptoms were markedly improved. Ten pyogenic bacterial strains were isolated from 10 patients, and all were eradicated in the 7 patients in whom bacteriological evaluation was possible. Mild loss of apetite and elevated S-GPT and BUN were observed, but no specific problematic side effects appeared. This new quinolone drug, for oral use, was considered to be a safe and useful in chemotherapy for respiratory infectious diseases.