Chemotherapeutic-bacteriological interdependences observed by use of a clinical anti-infective drug monitoring system.

The relationships between the extent and type of clinical antibacterial chemotherapy and bacteriological findings were investigated, both retrospectively and contemporaneously, by study of pharmacy deliveries and analysis of patient records and the results of bacteriological examination of urine. Initially, with a high proportion of tetracycline use and relatively little of ampicillin, co-trimoxazole and cephalosporins, E. coli was frequently found and seldom Klebsiella/Enterobacter; the in-vitro efficacy of tetracyclines was low against all bacteria tested. Deliberate restraint in the use of tetracyclines and promotion of co-trimoxazole as well as a spontaneous rise in ampicillin use, were correlated with a decrease in E. coli and increase in Klebsiella/Enterobacter. The in vitro susceptibility of Klebsiella to all the chemotherapeutics tested was relatively low, but it improved markedly after use of cefuroxime was begun. This resulted in a decrease in the incidence of Klebsiella/Enterobacter in urine specimens. Restraint in tetracycline usage was accompanied by an increase in its in vitro efficacy against E. coli. The study shows that continuous monitoring of antibacterial chemotherapy under routine conditions enables the clinical pharmacologist to recognize transient and locally specific circumstances and to define guidelines or corrective recommendations as a basis for and to aid control of real therapeutic decisions.