Characteristics of biliary excretion of cefazolin and other cephalosporins with reference to the relationship between serum levels and administration conditions

Role of cephalosporins in the era of Clostridium difficile infection

The incidence of Clostridium difficile infection (CDI) in Europe has increased markedly since 2000. Previous meta-analyses have suggested a strong association between cephalosporin use and CDI, and many national programmes on CDI control have focused on reducing cephalosporin usage. Despite reductions in cephalosporin use, however, rates of CDI have continued to rise. This review examines the potential association of CDI with cephalosporins, and considers other factors that influence CDI risk. EUCLID (the EUropean, multicentre, prospective biannual point prevalence study of CLostridium difficile Infection in hospitalized patients with Diarrhoea) reported an increase in the annual incidence of CDI from 6.6 to 7.3 cases per 10 000 patient bed-days from 2011-12 to 2012-13, respectively. While CDI incidence and cephalosporin usage varied widely across countries studied, there was no clear association between overall cephalosporin prescribing (or the use of any particular cephalosporin) and CDI incidence. Moreover, variations in the pharmacokinetic and pharmacodynamic properties of cephalosporins of the same generation make categorization by generation insufficient for predicting impact on gut microbiota. A multitude of additional factors can affect the risk of CDI. Antibiotic choice is an important consideration; however, CDI risk is associated with a range of antibiotic classes. Prescription of multiple antibiotics and a long duration of treatment are key risk factors for CDI, and risk also differs across patient populations. We propose that all of these are factors that should be taken into account when selecting an antibiotic, rather than focusing on the exclusion of individual drug classes.

Laboratory evaluation of FR10024 a new cephalosporin derivative

FR10024 is a broad-spectrum antibiotic. The in vitro antibacterial activity of FR10024 against clinical isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis is greater than that of any of the cephalosporins developed to date. Indole-positive Proteus, Enterobacter, and Citrobacter are resistant to FR10024, as is true for the other cephalosporins. However, more than half of the strains of Enterobacter and Citrobacter tested were susceptible to FR10024 at an inoculum of 10(6) cells/ml. A single subcutaneous injection of FR10024 to mice with peritoneal infections due to S. aureus and several species of gram-negative bacilli gave a protective effect inferior to that of cefazolin but appeared to be superior to that of cephalothin. When given in two divided doses, however, the protective effect of FR10024 was enhanced and almost equaled that of cefazolin. The serum levels and rates of urinary recovery of FR10024 varied in different animal species. The mean peak serum level of FR10024 in humans after a single intramuscular injection of 500 mg was two times higher than that of cephalothin. The serum half-life after intramuscular injections of 250 and 500 mg was slightly shorter than that of cephalothin. After receiving 250 mg of FR10024 intramuscularly the urinary recovery rate was 87.7% in healthy volunteers. The biliary excretion rate of FR10024 was particularly high. The 24-h excretion of FR10024 in rats was 63.3%, this being six to seven times higher than that for cefazolin, which has the highest biliary excretion of the other known cephalosporins. When FR10024 was injected intramuscularly (20 mg/kg), it was found that the hepatic levels of FR10024 in rats were the highest of all the cephalosporins, including cefazolin, but the levels of FR10024 in other tissues were not as high as those of cefazolin.