High pressure liquid chromatographic analysis of the serum concentration of cefuroxime after an intravenous bolus injection of cefuroxime in patients with a coronary artery bypass grafting

Clinical on-site monitoring of ß-lactam antibiotics for a personalized antibiotherapy

An appropriate antibiotherapy is crucial for the safety and recovery of patients. Depending on the clinical conditions of patients, the required dose to effectively eradicate an infection may vary. An inadequate dosing not only reduces the efficacy of the antibiotic, but also promotes the emergence of antimicrobial resistances. Therefore, a personalized therapy is of great interest for improved patients' outcome and will reduce in long-term the prevalence of multidrug-resistances. In this context, on-site monitoring of the antibiotic blood concentration is fundamental to facilitate an individual adjustment of the antibiotherapy. Herein, we present a bioinspired approach for the bedside monitoring of free accessible ß-lactam antibiotics, including penicillins (piperacillin) and cephalosporins (cefuroxime and cefazolin) in untreated plasma samples. The introduced system combines a disposable microfluidic chip with a naturally occurring penicillin-binding protein, resulting in a high-performance platform, capable of gauging very low antibiotic concentrations (less than 6 ng ml^-1) from only 1 µl of serum. The system's applicability to a personalized antibiotherapy was successfully demonstrated by monitoring the pharmacokinetics of patients, treated with ß-lactam antibiotics, undergoing surgery.

Comparison of Vancomycin and Cefuroxime for Infection Prophylaxis in Coronary Artery Bypass Surgery

OBJECTIVE: To investigate clinically significant differences between vancomycin and cefuroxime for perioperative infection prophylaxis in coronary artery bypass surgery.

DESIGN: A total of 884 patients were randomized prospectively to receive either cefuroxime (444) or van-comycin (440) and were assessed for infectious complications during hospitalization and 1 month postoperatively.

SETTING: A university hospital.

RESULTS: The overall immediate surgical-site infection rate was 3.2% in the cefuroxime group and 3.5% in the vancomycin group (difference, −0.3; 95% confidence interval, −2.6-2.1).

CONCLUSIONS: The data suggest that vancomycin has no clinically significant advantages over cephalosporin in terms of antimicrobial prophylaxis. We suggest that cefuroxime (or first-generation cephalosporins, which were not studied here) is a good choice for infection prophylaxis in connection with coronary artery bypass surgery in institutions without methicillin-resistantStaphylococcus aureusproblems. In addition to the increasing vancomycin-resistant enterococci problem, the easier administration and usually lower price of cefuroxime make it preferable to vancomycin.

A population pharmacokinetic model for cefuroxime using cystatin C as a marker of renal function

AIMS

Since cefuroxime mainly is excreted by renal filtration, dosing is currently based on serum creatinine (Scr) or creatinine clearance (CLcr). However, it has been suggested that cystatin C (CysC) is superior to Scr as a marker of renal function. The aim of this prospective study was to develop a population model that describes the pharmacokinetics of cefuroxime and to investigate the usefulness of CysC as a covariate of the model parameters.

METHODS

Ninety-seven patients were studied (CLcr range 6.5-115 ml min(-1)). Blood samples (n = 407) for the determination of cefuroxime were withdrawn according to a sparse data sampling schedule and analysed by liquid chromatography mass spectrometry. The population analysis was performed in NONMEM.

RESULTS

A two-compartment model described the data well. The biomarkers Scr, CLcr and CysC were evaluated as covariates on clearance (CL). The model that included CysC generated the best fit. In the final population model CL was a function of CysC and body weight, whereas V(1) was only a function of body weight. Final parameter estimates (relative standard errors) were 6.00 (3.2%) l h(-1), 11.4 (5.3%) l and 5.11 (11%) l for CL, V(1) and V(2), respectively.

CONCLUSIONS

Based on the results of the present study, and because CysC is practical to use in the clinic, it is suggested that individual dosing of cefuroxime may be based on CysC rather than on Scr or CLcr. Furthermore, our final population model may be useful as a tool when designing new dosing schedules for cefuroxime.

Determination of cefuroxime in human serum or plasma by liquid chromatography with electrospray tandem mass spectrometry

Cefuroxime is a second-generation cephalosporin used against different kinds of bacterial infections. To be able to optimize the dosing it is necessary to characterize the pharmacokinetics of cefuroxime which requires a selective and sensitive analytical method for cefuroxime in plasma or serum. A new rapid liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) method, using cefotaxime as internal standard, was developed for analysis of cefuroxime in human serum. The work-up procedure consisted of protein precipitation with acetonitrile/cefotaxime, and after centrifugation the supernatant was dissolved in mobile phase. The sample was injected on a SB-CN column and the detection was performed using tandem mass spectrometry (MS/MS). The limit of quantification was determined to 0.025 microg/mL. The method was linear in the range 0.025-50 microg/mL with a coefficient of correlation >0.999. The limit of quantification and intra-day variability were found to be the same for plasma samples, which indicates that the method is valid for serum as well as plasma samples.

Is single-dose antibiotic prophylaxis sufficient for coronary artery bypass surgery? An analysis of peri- and postoperative serum cefuroxime and vancomycin levels

Preliminary findings have suggested that a single intravenous dose of antibiotic is effective for infection prophylaxis in cardiac surgery. However there are still insufficient data on this proposed regimen. We measured serum cefuroxime and vancomycin levels after three different dosage regimens, in patients undergoing coronary artery bypass grafting (CABG). Sixty patients were randomized into three cefuroxime and three vancomycin groups with 10 patients in each: a group given a one-day course, or an additional dose during cardiopulmonary bypass or a single dose. Serum levels of the antibiotics were measured at various times throughout the operative procedure and until 48 h after the start of prophylaxis. Each of the six dosage regimens maintained serum levels adequate for infection prophylaxis throughout the operative procedure. Serum levels remained above 2 mg/L for more than 8 h postoperatively, even in the single-dose cefuroxime group and above 4 mg/L for more than 24 h with all the vancomycin dosage regimens. Thus a single dose of cefuroxime (3 g or 1.5 g) or vancomycin (1.5 g) seems to achieve and maintain serum levels sufficient for infection prophylaxis several hours after CABG procedures.

Measurement of cefuroxime in human bronchoalveolar lavage fluid by high-performance liquid chromatography after solid-phase extraction

A sensitive and selective method for the determination of cefuroxime in bronchoalveolar lavage (BAL) fluid using high-performance liquid chromatography (HPLC) with UV detection at 280 nm after solid-phase extraction with C18 cartridges was developed. A Waters symmetry C18 column was used and the mobile phase was acetonitrile-0.05 M ammonium phosphate buffer (pH 3.2) (15:85, v/v). The method enabled the determination of cefuroxime at concentrations below 100 ng/ml, with a linear calibration curve at concentrations of 5-100 ng/ml for 400 microliters of BAL. The intra- and inter-assay coefficient of variations for 10, 40 and 80 ng/ml were between 5.3 and 8.9%. Analytical recoveries were between 92.7 and 106.2%. The detection limit was 1 ng/ml at a signal-to-noise ratio of 3:1 using 400 microliters of BAL. The method was successfully used for the analysis of BAL fluid from patients after oral administration of 500 mg cefuroxime axetil twice daily.

The myth of the second prophylactic antibiotic dose in aortoiliac reconstructions

OBJECTIVES

To determine whether a prophylactic second dose of antibiotics is justified when severe blood loss and/or prolonged operation time occurs during aortoiliac reconstructions.

METHODS

We measured the cefuroxime concentration in venous blood serum and subcutaneous fat tissue of 30 patients who underwent elective aortoiliac reconstruction after a single intravenous dose of 1500 mg cefuroxime.

RESULTS

The mean blood loss was 1912 ml (range 200-7000). The mean operation time was 212 min (range 70-330). The cefuroxime concentration in blood serum 30 min after the gift varied from 53.7-561.6 mg/l and during closure of the abdominal incision from 13.2-90.0 mg/l. Taking the minimum inhibitory concentration for Staphylococcus species as 1.0 mg/l, we found an adequate prophylactic serum cefuroxime concentration in all patients. There was a statistically significant correlation between serum cefuroxime concentration and blood loss (p = 0.01) and operation time (p = 0.0001).

CONCLUSIONS

Although serum concentration of cefuroxime is greatly influenced by blood loss and operation time, a second dose of cefuroxime in aortoiliac reconstructions is not necessary if the operation is completed within 5.5 h and if perioperative blood loss does not exceed 7000 ml.

Prospective randomised comparison of single-dose versus multiple-dose cefuroxime for prophylaxis in coronary artery bypass grafting

To assess the efficacy of single-dose antibiotic prophylaxis in coronary artery bypass grafting, 1,016 consecutive patients were prospectively randomized to receive either a single dose or a three-day course of cefuroxime. Nine patients (0.9%) died within seven days; no death was caused by infection. For various reasons 163 other patients were not evaluable. Therefore, 844 patients were evaluated. Patients in group A (n = 419) received 20 mg/kg cefuroxime intravenously at induction of anaesthesia; group B (n = 425) received the same dose followed by 750 mg t.i.d. for three consecutive days. Both groups were comparable regarding all risk factors. The efficacy of the prophylactic regimens was evaluated by comparison of occurrence of wound infection in both groups. No significant differences in wound infection were observed between the two treatment groups: sternal site infection in the single-dose prophylaxis group was 14% versus 13% in the three-day course group; donor site infection occurred in 38% versus 39%. It is concluded that in coronary artery bypass grafting a single dose of cefuroxime is as effective as a three-day course in the prevention of wound infection.