Gram-positive/negative bacteria fluoroquinolones

AAC Aminoglycosides, fluoroquinolones Gram-negative and gram-positive bacteria Plasmid, transposon, chromosome... 

Nitrofurantoin is bacteriostatic and bactericidal for many gram-positive and gram-negative bacteria but P aeruginosa and many strains of proteus are resistant. There is no cross-resistance between nitrofurantoin and other antimicrobial agents and resistance emerges slowly. As Escherichia coli resistant to trimethoprim-sulfamethoxazole and fluoroquinolones has become more common, nitrofurantoin has become an important alternative oral agent for treatment of uncomplicated urinary tract infection. 

Levofloxacin 258 is a third generation of fluoroquinolone type antibiotic. This medicine is effective against a number of Gram-positive and Gram-negative bacteria. Because of its broad spectrum of action, 258 is frequently used for symptomatic treatment of infections of unknown etiology. 

Effects of the chiral fragments, such as l-(cw-2-fluorocyclopropyl) and 7-(7-amino-5-azaspiro[2.4]heptyl) substituents (compounds 32b, 33a) on antibacterial properties of the series of fluoroquinolones have been studied (Scheme 18) [123]. It has been shown that derivatives of l-[(ii(,25)-2-fluorocyclopropyl]- and 7-[(7S)-amino-5-azaspiro[2.4]heptyl]-fluoroquinolones are more active towards a number of Gram-positive and Gram-negative bacteria, than other stereoisomers. The presence of spiropyrrolidine residue at C(7) of fluoroquinolones enhances their lipophilic properties, thus promoting a better assimilation on oral administration [98]. 

---