Infectious Complications with Respiratory Pathogens despite Ciprofloxacin Therapy

To the Editor: Ciprofloxacin, a fluoroquinolone, is widely used for a broad range of infections. 1 Although it has had some success in treating respiratory tract infections, delayed clinical responses and the failure to eradicate pathogens from sputum have been reported in some patients with Streptococcus pneumoniae 2 In addition, its in vitro activity against gram-positive cocci is marginal. 1 , 3 Minimal inhibitory concentrations for S. pneumoniae and group A streptococcus range from 1 to 4 μg per milliliter, whereas the maximal serum level achieved after a 500-mg oral dose is approximately 2.5 μg per milliliter. 4 We report here the cases of six patients . . .