In Vitro Activities of Ceftriaxone-Sulbactam against Major Aerobic and Anaerobic Bacteria from Clinical Samples

ABSTRACT

BACKGROUND: beta-lactam antibiotics are one of the most common antimicrobial agents. However, the increasing of beta-lactamase-producing bacteria makes these agents less useful. Therefore, agents stable for beta-lactamase have been developed. This study was conducted to determine the activities of the combination agent ceftriaxone-sulbactam and to compare its activities with other agents. METHODS: A total of 437 clinical isolates of aerobic and anaerobic bacteria were collected in Severance Hospital from 2007 to 2011. Using 23 antimicrobial agents, antimicrobial susceptibility tests were performed using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. RESULTS: The minimal inhibitory concentrations (MICs) of ceftriaxone and ceftriaxone-sulbactam were similar to or lower than those of other beta-lactam antibiotics for methicillin-susceptible Staphylococcus aureus (MSSA), Streptococcus pneumoniae, S. pyogenes, and viridans group streptococci. For Moraxella catarrhalis, Neisseria gonorrhoeae, Haemophilus influenzae, and H. parainfluenzae, ceftriaxone and the ceftriaxone-sulbactam combination also show low MIC50 and MIC90. For extended-spectrum beta-lactamase (ESBL)-producing E. coli, the MICs of ceftriaxone-sulbactam were lower than those of other cephalosporins. Among the anaerobes, ceftriaxone-sulbactam showed good activity compared to ceftriaxone alone for the Bacteroides fragilis group, B. thetaiotaomicron, other Bacteroides sp., Prevotella sp., and Porphyromonas sp. CONCLUSIONS: Ceftriaxone-sulbactam showed good antimicrobial activity and thus is useful for the treatment of infections by MSSA, S. pneumoniae, S. pyogenes, viridans group streptococci, M. catarrhalis, N. gonorrhoeae, H. influenzae, H. parainfluenzae, E. coli, and K. pneumoniae, B. fragilis group, B. thetaiotaomicron, other Bacteroides sp., Prevotella sp., and Porphyromonas sp.