Utilization ofd-tartaric acid bySalmonella paratyphi BandSalmonella java: comparison of anaerobic plate test, lead acetate test and turbidity test

Abstract

SUMMARYd-Tartrate dehydrase ofSalmonella javais an oxygen-sensitive enzyme active in cultures incubated under the poorly aerated conditions of static culture but not in fully aerated shaken cultures nor on plates incubated aerobically. On plates ofd-tartrate minimal agar incubated anaerobically the enzyme or the degradation products ofd-tartrate are exported fromd-tartrate-positive cells and are available tod-tartrate-negative bacteria. This may give misleading growth results whend-tartrate-positive andd-tartrate-negative strains are tested for growth on the same plate ofd-tartrate minimal agar.The lead-acetate test terminated at 24 h, the 24 h turbidity test and the ability to grow ond-tartrate minimal agar within 48 h differentiated 53S. paratyphi Bstrains that were negative in each of the three tests from 76S. javathat were positive in each of the tests. An intermediate group of eight strains utilizedd-tartrate in Difco bacto-peptone water to give a positive lead acetate reaction at 2 days, were stimulated to a varying degree byd-tartrate in Oxoid peptone water within the same period of incubation and grew poorly ond-tartrate minimal agar. These latter strains may be deficient in a permease controlling uptake ofd-tartrate or export ofd-tartrato dehydrase.Inability to utilized-tartrate is unlikely to be the single character accountable for the reputed enhanced pathogenicity ofS. paraptyphi Bwhen compared withS. java.Indications for the existence of an enzyme, complementary to and mutually exclusive withd-tartrate dehydrase, that has a positive correlation with pathogenicity are discussed.