Timentin (ticarcillin (TCR) + clavulanic acid (AC)) was given for severe bacterial infections to sixteen hospitalized patients (10 male and 6 female; 16 to 75 years of age; normal renal function in 12). Infections included 8 septicemias (of which 4 were secondary to pyelonephritis), 6 pyelonephritis (in addition to the four above-mentioned cases), and 3 suppurated cellulitis of the lower limbs (with septicemia in one case). The following bacteria were recovered: 10 Escherichia coli, 1 Pseudomonas aeruginosa, 1 Enterobacter cloacae, 1 Providencia stuartii, 1 Salmonella typhi, 1 Klebsiella pneumoniae, and 1 Staphylococcus aureus. The sixteen strains were all susceptible to timentin (MICs determined by agar dilution: TCR + AC 4 mg/l: 0.5-16 mg/l; TCR + AC 8 mg/l: 0.2-16 mg/l). Thirteen strains were susceptible to TCR (MIC less than or equal to 16 mg/l), and three (1 E. coli, 1 K. pneumoniae, and 1 S. aureus) were resistant to TCR (MIC greater than or equal to 256 mg/l). 14 patients received timentin alone, while two were also given dibekacin. Timentin was given in one-hour IV infusions in a dosage of 9.6 g/24 h (3.2 g X 3) in 10 patients and 6.4 g/24 h (3.2 g X 2) in 6. Duration of therapy was 14 to 16 days in half of cases (range 5 to 21 days). At termination of the infusion, serum concentrations of ticarcillin and clavulanic acid (determined in ten patients) were greater than 50 mg/l and 3-7.4 mg/l respectively, and serum bactericidal activity (evaluated in ten cases) was consistently less than 1/2.(ABSTRACT TRUNCATED AT 250 WORDS)