Disk diffusion method for susceptibility testing of Neisseria gonorrhoeae.
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The standard medium for disk diffusion and MIC testing of Neisseria gonorrhoeae (that of the National Committee for Clinical Laboratory Standards) was tested to establish zone correlations for the MIC breakpoints currently used in Sweden. Eight gonococcal control strains representing both susceptible and resistant strains and 50 clinical isolates were tested. The standard medium did not support the growth of two control strains and three clinical isolates when the standardized inoculum was used in the disk diffusion test. The same medium with the addition of hemoglobin was introduced. This medium supported the growth of all strains. The correlations between the MICs and the zones of inhibition were calculated for penicillin, ampicillin, cefuroxime, erythromycin, tetracycline, doxycycline, ciprofloxacin, and spectinomycin. The range of MICs for the clinical isolates were broad, without bimodal distribution, for all antibiotics, except ciprofloxacin and spectinomycin. With the susceptibility distribution of MICs and zones near the current susceptible and intermediate or intermediate and resistant limits, a low reproducibility of tests and a high frequency of minor interpretive errors can be expected. A revision of MIC breakpoints seems warranted but can only be done after renewed clinical evaluation of different treatment regimens. (+info)
Timing of antibiotic prophylaxis for primary total knee arthroplasty performed during ischemia.
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Effect of malnutrition on the pharmacokinetics of cefuroxime axetil in young rats.
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PURPOSE: To determine the pharmacokinetics of cefuroxime axetil in malnourished rats using a diet with a restriction in energy and nutrients (group M), a diet with a low quality protein (group K) and a good quality diet (group C) as a control. METHODS: The rats were fed with the corresponding diet during 21 days. After this period a single oral dose of cefuroxime axetil (equivalent to a 2.2 mg dose of cefuroxime) was administered, and plasma samples were taken at 0, 5, 10, 30, 45, 60, 90, 120, 180, 240, 300 and 360 minutes; samples were assayed using an HPLC assay. Biochemical parameters were also measured an a microscopy study of the small intestine was done. After a 21 day period of recovery of the malnourished groups a second pharmacokinetic study was performed using the same sample times as in the first study. RESULTS: In malnourished animals of group K the levels of plasma proteins were low, and showed higher concentrations of fat in the liver. The relative bioavailability of cefuroxime was 78.2% for group M and 64.4% for group K. Groups M and K presented lower values of area under the curve, which means that the amount of antibiotic absorbed was lower than group C. In the second pharmacokinetic study although the animals received a good quality diet, it was observed that the area under the curve of group K was lower, and the relative bioavailability was 54.3%, while group M had similar pharmacokinetic values than control group. CONCLUSIONS: The pharmacokinetics of cefuroxime was affected by malnutrition, suggesting that the absorption process via the transporter was modified in the malnourished groups, specially in the group fed with a low quality protein. (+info)
The two-component system CesRK controls the transcriptional induction of cell envelope-related genes in Listeria monocytogenes in response to cell wall-acting antibiotics.
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Restoration of susceptibility of intracellular methicillin-resistant Staphylococcus aureus to beta-lactams: comparison of strains, cells, and antibiotics.
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Cefuroxime non-susceptibility in multidrug-resistant Klebsiella pneumoniae overexpressing ramA and acrA and expressing ompK35 at reduced levels.
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Tissue and plasma concentrations of antibiotic during cardiac surgery with cardiopulmonary bypass--microdialysis study.
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AIM: Surgical-site infections are very serious complications of cardiac operations. Use of cardiopulmonary bypass (CPB) is associated with profound physiological changes, which affects the pharmacokinetic behaviour of prophylactic antibiotics. The aim of this study was to monitor tissue concentrations of cefuroxime in peripheral tissue (skeletal muscle) during cardiac surgery using CPB by means of a microdialysis. METHODS: Eleven adult patients operated on using CPB were included in the study. Cefuroxime was the prophylactic antibiotic and study drug given. Microdialysis was performed by probe CMA 60 inserted into the patient's left deltoid muscle. Samples of dialysates were collected at intervals: before CPB, each 30 minutes of CPB and at the end of CPB. Samples of blood were collected at intervals: incision, start of CPB, each 30 minutes of CPB, at the end of CPB and at the end of surgery. RESULTS: The mean (+/- S.D.) concentrations of cefuroxime in peripheral tissue were 105.4+/-41.1, 81.7+/-32.8, 74.6+/-26.0, 70.4+/-34.7, 60.5+/-27.2, 138.0+/-42.6 (mg l(-1)). Total plasma concentrations of cefuroxime were 154.4+/-41.6, 73.3+/-20.7, 67.1+/-20.4, 59.2+/-21.0, 49.0+/-16.4, 110.9+/-33.6 (mg l(-1)) and concentrations of free plasma fraction were 110.7+/-37.1, 62.2+/-18.8, 58.9+/-18.6, 48.4+/-16.6, 41.7+/-15.6, 97.6+/-28.6 (mg l(-1)). The plasma and tissue concentrations exceed throughout the operation time the minimum inhibitory concentration for most common suspected pathogens in cardiac surgery. CONCLUSIONS: Results show that CPB can modify the time course of cefuroxime tissue and plasma concentrations. Microdialysis is suitable for antibiotic tissue measurement in cardiac surgery. (+info)