Its spectrum of activity includes most strains of bacterial pathogens responsible for respiratory, urinary tract, gastrointestinal, and abdominal infections, including Gram negative ("Escherichia coli"," Haemophilus influenzae", "Klebsiella pneumoniae", "Legionella pneumophila", "Moraxella catarrhalis", "Proteus mirabilis", and "Pseudomonas aeruginosa"), Gram positive (methicillin-sensitive but not methicillin-resistant "Staphylococcus aureus", "Streptococcus pneumoniae", "Staphylococcus epidermidis", "Enterococcus faecalis", and "Streptococcus pyogenes"), and atypical bacterial pathogens ("Chlamydophila pneumoniae" and "Mycoplasma pneumoniae").