Minimum Inhibitory concentration of carbapenems and tigecycline against Salmonella spp.

Antimicrobial resistance in Salmonella spp. is of grave concern, more so in quinolone-resistant and extended-spectrum beta-lactamase (ESBL)-producing isolates that cause complicated infections. The MIC of azithromycin, ciprofloxacin, cefixime, cefepime, ceftriaxone, gatifloxacin, imipenem, levofloxacin, meropenem and ofloxacin (E-test strip) and tigecycline and faropenem (agar dilution) against 210 Salmonella spp. was determined. MIC90 (defined as the antimicrobial concentration that inhibited growth of 90% of the strains) of the carbapenems (imipenem and meropenem) for Salmonella Typhi and Salmonella Paratyphi A was 0.064 mu g ml(-1). MIC90 of faropenem was 0.25 mu g ml(-1) for S. Typhi, S. Paratyphi A and Salmonella Typhimurium. The MIC90 of azithromycin for all Salmonella spp. ranged from 8 to 16 mu g ml(-1). Tigecycline showed an MIC90 of 2 mu g ml-1 for S. Typhi, 1 mu g ml(-1) for S. Paratyphi A and 4 mu g ml(-1) for S. Typhimurium. We concluded that tigecycline and the carbapenems are likely to have roles in the final stage of treatment of quinolone-resistant and ESBL-producing multidrug-resistant salmonellae.