TABLE 3

Frequency of emergence of spontaneous drug-resistant mutants of M. abscessus when exposed to individual drugs and paired combinations that exhibit synergy in vitro

Drug combinationResistance frequency for:
Individual drugCombination
Cefuroxime and avibactam>2 × 10−6/—<1 × 10−10
Biapenem and avibactam8.9 × 10−8/—3.3 × 10−9
Cefoxitin and imipenem>2 × 10−6/1.9 × 10−7<1 × 10−10
Cefditoren and imipenem>2 × 10−6/1.9 × 10−7<1 × 10−10
Imipenem and doripenem1.9 × 10−7/9.9 × 10−89.1 × 10−9
Cefuroxime and cefditoren>2 × 10−6/>2 × 10−6<1 × 10−10
Cefditoren and biapenem>2 × 10−6/8.9 × 10−8<1 × 10−10
Cefdinir and imipenem7.8 × 10−9/1.9× 10−7<1 × 10−10
Cefuroxime and imipenem>2 × 10−6/1.9 × 10−7<1 × 10−10
Cefpodoxime and imipenem>2 × 10−6/1.9 × 10−7<1 × 10−10
Imipenem and biapenem1.9 × 10−7/8.9 × 10−81.1 × 10−9
Imipenem and avibactam1.9 × 10−7/—<1 × 10−10
Tebipenem and avibactam1.1 × 10−7/—<1 × 10−10
Ertapenem and avibactam8.3 × 10−8/—<1 × 10−10
Ertapenem and imipenem8.3 × 10−8/1.9 × 10−74.3 × 10−9
Imipenem and faropenem1.9 × 10−7/<1 × 10−10<1 × 10−10
Imipenem and rifabutin1.9 × 10−7/<1 × 10−10<1 × 10−10
Cefadroxil and tebipenem>2 × 10−6/1.1 × 10−71.3 × 10−8
Cefditoren and tebipenem>2 × 10−6/1.1 × 10−7<1 × 10−10
Cefadroxil and rifabutin>2 × 10−6/<1 × 10−10<1 × 10−10
Cefadroxil and rifapentine>2 × 10−6/<1× 10−10<1 × 10−10
Cefadroxil and rifampin>2 × 10−6/>2 × 10−6<1 × 10−10
Cefprozil and rifabutin>2 × 10−6/<1 × 10−10<1 × 10−10
Cefprozil and rifapentine>2 × 10−6/<1 × 10−10<1 × 10−10