Löffler Löff·ler (lěf'lər, lɶf'-), Friedrich August Johannes. 1852-1915.
German bacteriologist who isolated (1884) the bacillus the causative agent of diphtheria, previously described by Edwin Klebs.
German bacteriologist who in 1884 demonstrated that diphtheria was caused by a bacillus described by Edwin Klebs a year earlier. This bacillus is now named after both scientists. Löffler also isolated an organism that causes food poisoning and developed a vaccine against foot-and-mouth disease (1899).