TDO2 and benign neoplasm of brain: In S. Typhimurium, a 40 kb pathogenicity island (SPI-1) is inserted 5′ to the mutS gene [40] and in H. influenzae, a 3.1 kb tryptophanase gene cluster (tna) is inserted on the 3′ side of the mutS gene in strains that cause spinal meningitis in infants [41].