A bacillus (plural bacilli) is a rod-shaped bacterium. They sometimes form filaments, which fragment into bacilli or cocci once disturbed. Most plant pathogenic bacteria are rod-shaped (bacilli). Relapses have also occurred after appropriate treatment when infected by Gram-negative enteric bacilli. Incorporation of dead tubercle bacilli in the medium was successful. Fusobacteria are obligately anaerobic non-sporeforming Gram-negative bacilli. Biopsy will reveal tuberculoid granuloma with few bacilli. George Bernard Shaw called them "uncouth bacilli", referring to the apostrophe-like shape of many bacteria. This is used while preening and helps reduce bacterial degradation of feathers by feather bacilli. Ethambutol is bacteriostatic against actively growing TB bacilli. People infected with TB bacilli will not necessarily become sick with the disease. Pasteur publicly claimed he had made the anthrax vaccine by exposing the bacilli to oxygen. They are Gram-negative, non-fermenting, aerobic bacilli. Short, relatively plump bacilli (rods) in tissue smears, large slender beaded rods in culture. Medically relevant gram-negative bacilli include a multitude of species.