Search

To determine the magnitude of cloxacillin loss during surgical procedures involving significant blood loss and high fluid replacement, we compared the pharmacokinetics of cloxacillin in children during craniomaxillofacial surgery with the disposition of the drug in healthy young adult volunteers with intact circulation. Blood loss during craniofacial operations may exceed blood volume, in some cases by as much as three times. Hemodynamic replacement with electrolyte solutions and blood products, which do not contain the drug, further dilute cloxacillin concentrations. In the patients that we studied, mean drug loss was estimated at 71%. Cloxacillin concentrations in serum fell below the lower range of the MIC for Staphylococcus aureus during significant portions of the surgical procedures. Thus, the traditional dosing of cloxacillin during prolonged operations with massive blood loss is inadequate. A more frequent dosing interval or priming of all replacement fluids with the drug may be required to maintain therapeutic levels. Our findings suggest that massive blood loss is likely to have a dramatic effect on the level of any drug with a small distribution volume. If such a drug is essential to the patient's well-being (e.g., antibiotics, antiarrhythmics, and anticonvulsants), it must be replaced promptly.

An accurate, plate diffusion bioassay for ticarcillin, utilizing the fast-replicating Beneckea natriegens and 4% salt agar, is described in this report. Zones of inhibition were well defined after 3 h, and the limit of sensitivity was around 5.0 μg/ml. The assay is simple to carry out, and duplicate assays can be performed on as little as 40 μl of serum.

Depending on the hematocrit, duplicate or triplicate determinations of serum amphotericin B concentration may be made on as little as 100 μl of capillary blood obtained by finger prick. In an accurate plate diffusion bioassay, using Paecilomyces varioti as the indicator organism, levels of the drug in the therapeutic range can be determined fast enough for clinicians to modify their next dose.

The in vitro antifungal activities of amphotericin B (AMB) and amphotericin B methyl ester (AME) were compared against 465 clinical isolates of Candida albicans . AMB and AME possessed comparable activity against half of the strains, but against the remainder of the strains the activity of AME was slightly lower than that of AMB. Rarely did AME show superior antifungal activity to AMB.

The susceptibilities to erythromycin, rifampin, polymyxin B, ampicillin, tetracycline, gentamicin, fusidic acid, trimethoprim, and spectinomycin of five virulent phase I strains of Bordetella pertussis and their degraded phase IV descendants were compared. Increases in MICs of 2- to 16-fold were observed for erythromycin, rifampin, tetracycline, fusidic acid, trimethoprim, and spectinomycin for four of the five degraded strains.

The in vitro activities of 16 cephalosporin derivatives and imipenem against 60 strains of Bordetella pertussis were examined. Cefoperazone, imipenem, and ceftriaxone were the most active, with MICs that inhibited 90% of the strains of 0.006, 0.05, and 0.1 microgram/ml, respectively. Cephalexin, cephradine, and cefsulodin were the least active, with MICs of 25 to 125 micrograms/ml. The remainder of the agents demonstrated intermediate activity.

The susceptibilities to erythromycin, rifampin, polymyxin B, ampicillin, tetracycline, gentamicin, fusidic acid, trimethoprim, and spectinomycin of 100 strains of Bordetella pertussis isolated between 1960 and 1981 were compared. No change in susceptibility to any of these drugs was noted.

A total of 100 and 97% of Haemophilus influenzae type b strains from major infections were susceptible, respectively, to levels of rifampin and sulfisoxazole attainable in saliva. It is theoretically feasible to eliminate Haemophilus influenzae from the nasopharynx with these drugs.

Amphotericin B assays on frozen serum samples (−20°C) generally underestimate the serum levels obtained on promptly processed samples. The degree of the discrepancy is variable and independent of the length of time stored.