EFFECTS OF SALMONELLA-TYPHIMURIUM INFECTION AND OFLOXACIN TREATMENT ON GLUCOSE AND GLUTAMINE-METABOLISM IN CACO-2 TC-7 CELLS/

The effects of both Salmonella typhimurium infection and 5 mM ofloxaci n treatment on 2 mM glutamine and 5 mM glucose metabolism in the enter ocyte-tike Caco-2/TC-7 cell line were studied. These cells utilized gl utamine (212.07 +/- 16.75 [mean +/- standard deviation] nmol per h per 10(6) viable cells) and, to a lesser extent, glucose (139.63 +/- 11.5 2 nmol per h per 10(6) viable cells). Metabolism of these substrates i n Caco-2/TC-7 cells resembled that in rat, pig, or human enterocytes. Infection by S. typhimurium C53-enhanced glucose and glutamine substra te utilization by 32 and 22%, respectively and enhanced glucose and gl utamine substrate oxidation by eight- and twofold, respectively. These increases in glucose and glutamine metabolism (especially glucose met abolism) were due in part to the metabolism of intracellular bacteria and/or to the activation of cellular metabolism. Substrate metabolism (especially glucose metabolism) in C53-infected cells was partially re duced by treatment with ofloxacin. It was concluded that cellular fuel metabolism is stimulated at the earliest stage of infection (3 to 4 h ) and that treatment with 5 mM ofloxacin does not completely restore s ubstrate metabolism to the levels observed in uninfected cells, possib ly because this treatment does not eradicate intracellular S. typhimur ium completely.