In vitro studies of alpha-carboxyl-3-thienylmethyl penicillin, a new semisynthetic penicillin

Ticarcillin: a review of its pharmacological properties and therapeutic efficacy

Ticarcillin is a semisynthetic penicillin for parenteral administration. The antibacterial activity of ticarcillin is similar to that of carbenicillin except that it is two to four times more active in vitro against Pseudomonas aeruginosa, generally less active against Gram-positive cocci and more active against most Gram-negative bacilli. As the pharmacokinetics of ticarcillin and carbenicillin are also similar, ticarcillin should theoretically be clinically effective when administered at a lower dosage than carbenicillin. There is some evidence that ticarcillin is comparable in efficacy with carbenicillin when given in half to two-thirds the dosage, when the drugs are given in combination with an aminoglycoside and in clinical situations where these drugs are agents of choice. Ticarcillin has been used successfully in the treatment of complicated urinary tract infection, pulmonary infection in cystic fibrosis and bacteraemia and is effective when combined with an aminoglycoside in severe infections in patients with granulocytopenia. The efficacy in anaerobic infections is at present poorly documented, although preliminary results are promising. Tolerability has generally been good with hypokalaemia being the most frequently reported side effect. At the dosages used, bleeding and fluid overload have seldom occurred.

Comparison of ticarcillin and carbenicillin activity against random and select populations Pseudomonas aeruginosa

The in vitro activities of ticarcillin (T) and carbenicillin (C) against 253 strains of Pseudomonas aeruginosa (108 randomly selected clinical isolates and 145 isolates determined to be C resistant by 10 referring hospitals) were evaluated using both broth microdilution and disk diffusion techniques. T activity was usually twofold or greater than C activity for individual strains in both sample populations. The minimal inhibitory concentration (MIC) values of T and C were </=0.4 to >400 (median, 25) and 0.8 to >400 (median, 50) mug/ml, respectively, for the random sample and 1.6 to >400 (median, 50) and 12.5 to >400 (median, 200) mug/ml, respectively, for the select sample. For predicting susceptibility (MIC, </=50 mug of T and </=100 mug of C per ml), 75-mug T and 100-mug C disks were equivalent in accuracy for the random sample (T/T = 92.6%, T/C = 92.0%, C/T = 91.7%, C/C = 89.8%). Regression-line analyses of zones of inhibition versus MIC values for the four combinations showed coefficients of correlation to be -0.81, -0.76, -0.77, and -0.75, respectively. With the sample selected as being resistant to C, T was better than C for predicting T susceptibility (P < 0.05), and T was equivalent to C for predicting C susceptibility (T/T = 84.3%, T/C = 81.0%, C/T = 73.6%, C/C = 80.4%). Coefficients of correlation were -0.70, -0.74, -0.55, and -0.61, respectively. T and C disks were, therefore, equivalent for determining T and C susceptibilities, but the T disk was more reliable for determining T susceptibility in a population skewed with C-resistant strains.

Comparative susceptibility of anaerobic bacteria to ticarcillin, cefoxitin, metronidazole, and related antimicrobial agents

The in vitro antimicrobial activity of two newer agents, ticarcillin and cefoxitin, against 204 recent clinical isolates of anaerobic bacteria was determined by an agar dilution technique, and compared to their related compounds carbenicillin, cephalothin, and penicillin, as well as metronidazole, clindamycin, and chloramphenicol. Ticarcillin was similar to carbenicillin, and cefoxitin was more active than cephalothin. At readily achievable blood concentrations of each antimicrobial agent, ticarcillin was slightly less active than clindamycin against Bacteroides fragilis. Cefoxitin was superior to cephalothin and penicillin against B. fragilis. Penicillin remained highly active against all obligate anaerobes other than B. fragilis. Metronidazole, while highly effective against B. fragilis and Clostridium perfringens, was only intermediately effective against anaerobic gram-positive cocci and relatively inactive against nonsporulating anaerobic gram-positive bacilli. Further evaluation of the clinical efficacy of ticarcillin, carbenicillin, and cefoxitin against anaerobic infections is indicated.

Ticarcillin in the treatment of experimental pseudomonas keratitis

In rabbits with experimental Pseudomonas aeruginosa keratitis the subconjunctival administration of either ticarcillin or gentamicin significantly ameliorated the keratitis and reduced the number of organisms to be found in the cornea. The use of these drugs in combination had an additive effect in vitro studies and a significantly more beneficial effect on the clinical disease than the use of either drug alone.

Comparative activity in vitro of ticarcillin, BL-P1654, and carbenicillin

The activity of ticarcillin, BL-P1654, and carbenicillin was compared in vitro using a microtiter tube dilution test in Mueller-Hinton broth against 50 recent clinical isolates each of Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella species, Enterobacter species, Proteus species, and Pseudomonas aeruginosa. Bactericidal end points were determined using a modified Steers replicator. Ticarcillin was generally two to four times more active against all organisms tested except S. epidermidis against which BL-P1654 was most active. Median minimum inhibitory concentrations in micrograms per milliliter were for S. aureus: ticarcillin (6.2), carbenicillin (12.5), BL-P1654 (25); for S. epidermidis: BL-P1654 (1.6), ticarcillin (3.2), carbenicillin (3.2); for E. coli: ticarcillin (3.2), BL-P1654 (6.2), carbenicillin (6.2); for Klebsiella sp.: >100 for all three drugs; for Enterobacter sp.: ticarcillin (3.2), carbenicillin (6.2), BL-P1654 (12.5); for Proteus sp.: ticarcillin (1.6), carbenicillin (1.6), BL-P1654 (3.2); for P. aeruginosa: ticarcillin (31), BL-P1654 (62), carbenicillin (125). Bactericidal end points were dependent on both the drug and the species but were in general no more than twofold more than the minimum inhibitory concentration with the exception of BL-P1654 against P. aeruginosa. BL-P1654 was bactericidal for only 60% of the strains tested at a concentration of 500 mug/ml.

Study of the effects of ticarcillin on blood coagulation and platelet function

Ticarcillin is a new semisynthetic penicillin similar to carbenicillin. Since carbenicillin has been shown to inhibit platelet function to such an extent that bleeding may accompany its use, an investigation of the effects of ticarcillin on hemostasis was made. The drug was administered to 17 human volunteers for periods of 3 to 10 days in intravenous doses of 100, 200, or 300 mg/kg per day (7 to 21 g/day). Serial studies of blood coagulation and platelet function indicated that coagulation was unaffected by ticarcillin but that platelet function became defective in all subjects. Abnormal platelet function was evidenced by lengthening of bleeding time (17 of 17 volunteers), depressed adenosine diphosphate-induced platelet aggregation (17 of 17), defective collagen-induced aggregation (15 of 17), and abnormal epinephrine-induced aggregation (10 of 17). Prothrombin consumption, due to reduced platelet procoagulant activity, was significantly decreased with a dose of 300 mg/kg per day. Comparison of results from this study with those from an earlier carbenicillin study revealed that ticarcillin at 300 mg/kg per day produces the same defects in hemostasis as does carbenicillin at 300 mg/kg per day, but that lower doses (100 or 200 mg/kg per day) of ticarcillin result in only a mild defect in platelet function. If the effective dose of ticarcillin is proven to be lower than the doses of carbenicillin currently employed for treatment of certain gram-negative infections, bleeding should not be a frequent complication of ticarcillin administration, when the drug is given to patients with normal renal function.

BL-P1654, ticarcillin, and carbenicillin: in vitro comparison alone and in combination with gentamicin against Pseudomonas aeruginosa

Minimum inhibitory concentrations of carbenicillin, ticarcillin, and BL-P1654 were determined for 89 clinical isolates of Pseudomonas aeruginosa. Ticarcillin was generally twice as active and BL-P1654 eight to 16 times as active as carbenicillin. Usually carbenicillin and ticarcillin killed at the same concentration or twice the concentration needed to inhibit, whereas 400 mug of BL-P1654 per ml was not bactericidal for the majority of isolates tested. The inhibitory effect of all three drugs varied markedly with the size of bacterial inoculum. When therapeutically achievable concentrations were used, adding gentamicin enhanced the inhibitory and bactericidal activity of all three penicillin derivatives for the majority of isolates. However, inhibition of isolates highly resistant to gentamicin was not improved by combining the semisynthetic penicillins with gentamicin.

Morphological alterations of Pseudomonas aeruginosa by ticarcillin: a scanning electron microscope study

Pseudomonas aeruginosa was exposed to 0.1, 1.0, 10, 100, and 1,000 times the minimal inhibitory concentration of ticarcillin in vitro and subsequently examined with the scanning electron microscope. The morphological alterations observed were filamentation, mid-cell defects, and spheroplast formation, and these alterations were dependent upon the drug concentration.

Ticarcillin therapy of infections

Ticarcillin was administered as initial therapy during 73 episodes of infections occurring in 69 adults with neoplastic diseases. During the first six infections, doses of 5 gm were dissolved in 200 ml of solvent and administered intravenously over a 2-h period every 6 h. Four of six infections responded to therapy. However, two of the five Pseudomonas infections failed to respond, whereas the organisms causing the infection were sensitive to ticarcillin in vitro. During the remaining 67 infections, doses of 3.5 g were similarly dissolved and administered intravenously over a 2-h period every 4 h. The overall response to ticarcillin in these 67 infections was 43%. However, 18 of 20 Pseudomonas infections, three Proteus spp. infections, and one infection caused by H. influenzae responded. Only 1 of 7 infections caused by mixed organisms and 5 of 13 infections in which the etiologic agent could not be identified responded. Ticarcillin was ineffective against the majority of Escherichia coli and Klebsiella spp. infections, organisms which were resistant to ticarcillin in vitro. The majority of patients were neutropenic, but the response rate was not dependent on the number of circulating polymorphonuclear neutrophilic leukocytes. Superinfection occurred in seven patients. Erythematous skin rash occurred in two patients, which subsided after discontinuation of the drug. No liver or renal toxicity occurred that could be attributed to ticarcillin.

Clinical pharmacology of ticarcillin (alpha-carboxyl-3-thienylmethyl penicillin, BRL-2288)

Clinical pharmacological studies of ticarcillin (alpha-carboxyl-3-thienylmethyl penicillin, BRL-2288) were conducted in patients with metastatic cancer and leukemia. After administration of 0.5 g intramuscularly, 1 g intramuscularly, and 1 g intravenously, the mean peak concentrations in serum were 18, 35, and 106 mug/ml, respectively. Greater than 80% of ticarcillin was excreted in the urine during the subsequent 6-h period. The mean concentrations in the serum of patients 15 min after they received an intravenous injection of 4 g of ticarcillin with and without probenecid were 508 and 519 mug/ml, respectively. Serum levels were determined in patients who received ticarcillin for therapy of infection in doses of 5 g every 6 h. The mean drug concentration in serum 15 min after the rapid administration of the first dose was 433 mug/ml. Subsequent doses were given during a 2-h infusion and the study was repeated 2 days later. The average initial serum level (4 h after the completion of the preceding dose) was 19 mug/ml, and the mean serum level at 15 min was 213 mug/ml. Drug concentrations in the serum of patients receiving ticarcillin by infusion in doses of 3.5 g every 4 h were also determined. In patients with normal renal function, the average initial serum level (2 h after completion of the preceding dose) was 49 mug/ml and the mean level at 15 min was 210 mug/ml. Drug concentrations in the serum of patients with impaired renal function were considerably higher. No detectable levels of ticarcillin were found in the cerebrospinal fluid.