SENSITIVITY OF ESCHERICHIA-COLI TO PROLINE ANALOGS DURING OSMOTIC-STRESS AND ANAEROBIOSIS

The sensitivity of wild-type Escherichia coli K-12 to a series of prol ine analogues was determined in cultures containing increasing concent rations of NaCl under both aerobic and anaerobic conditions. The bacte ria were most sensitive to L-azetidine-2-carboxylate and L-thiazolidin e-4-carboxylate. The minimum inhibitory concentrations for these compo unds decreased progressively during osmotic stress, but the bacteria w ere much more sensitive to these proline analogues under aerobic condi tions than during anaerobiosis. The reduced sensitivity under anaerobi c conditions did not reflect degradation of the compounds in the cultu re medium. Since both urine and medullary renal tissue contain relativ ely low oxygen concentrations, these results raise doubts about the po tential use of proline or glycine betaine analogues in treating urinar y tract infections.