Background:

Pneumococcal drug resistance has become a worldwide problem.

Objective:

This study examined the anti-pneumococcal activity of BAL9141, a new broad-spectrum intravenous cephalosporin, compared with those of amoxicillin, imipenem, ertapenem, cefepime, ceftriaxone, cefotaxime, cefuroxime, cefdinir, levofloxacin, moxifloxacin, azithromycin, clarithromycin, linezolid, quinupristin/dalfopristin, daptomycin, vancomycin, teicoplanin and telithromycin. Strains included 30 PSSP, 60 PISP and 209 PRSP (n = 299); of these, 152 (51%) were macrolide-resistant and 39 (13%) were levofloxacin-resistant (both groups with defined resistance genotypes).

Methods:

Agar dilution MIC with cation-adjusted Mueller–Hinton agar + 5% sheep blood and inocula of 104 CFU/spot were used. The following MIC50/MIC90 values (mg/mL) were obtained: Although MICs of all b-lactams rose with those of penicillin G, BAL9141 had the lowest MICs of all cephalosporins tested. Using NCCLS IV cephalosporin nonmeningeal pneumococcal breakpoints, 98.3% of strains were S, 1.3% I, and 0.3% R to BAL9141; compared with 73.2% S, 20% I, and 6.7% R with ceftriaxone and 70.9% S, 24% I, and 5% R with cefepime. All strains were S to quinupristin/dalfopristin, daptomycin, vancomycin and teicoplanin, and 93.3% S to telithromycin (breakpoint 0.5 mg/mL).

Conclusions:

BAL 9141 had the lowest MICs (similar to carbapenems) of all IV cephalosporins tested against pneumococci irrespective of a strain's b-lactam, macrolide or quinolone susceptibility.