Cephradine

Serum and brain tissue concentrations were determined after i.v. administration of 4 g cephradine to 11 patients of whom 6 were additionally receiving 40 mg furosemide t.i.d. peroral. Five further patients were given 4 g cephalothin i.v. All patients were undergoing a brain operation at the time of antibiotic administration. Between 60 and 100 min after dosage, cephradine decreased in the serum from 104.9 mcg/ml to 56.7 mcg/ml and in the brain tissue from 13.02 mcg/g to 8.37 mcg/g in the mean. Cephradine concentrations in serum were higher and in brain tissue lower when furosemide was given as well. These differences are statistically significant (p less than 0.01). Serum concentrations of cephalothin over the same period and in the absence of furosemide were very low with 32.2 mcg/ml at 60 to 70 min, and extremely low in the brain tissue (0.55 mcg/g in the mean) so that a trial with furosemide was not performed. Neither antibiotic was detectable in the cerebrospinal fluid. The differences in serum and brain tissue concentrations of cephradine in the presence and absence of furosemide demonstrate that special care must be taken when administering more than one drug.

A Pseudomonas fluorescens strain ZY2, isolated from swine wastewater, was used to investigate the synergistic effects of five heavy metals (Pb, Cu, Zn, Cr(VI) and Hg) on bacterial resistance to antibiotics. Results indicate that the combined effects of antibiotic type, heavy metal type and concentration were significant (p < 0.01). Cross-resistance to Hg and antibiotics was the most noticeable. Moreover, the resistance to Hg and cefradine or amoxicillin, and Cr and amoxicillin were synergistic for low heavy metal concentrations, and turned antagonistic with increasing concentrations, while the resistances to Cr or Cu and cefradine, Pb or Cu and amoxicillin, Cu and norfloxacin showed reverse effects. In addition, resistance to Zn and amoxicillin were always synergetic, while resistance to Pb and cefradine or norfloxacin, Cr or Hg and norfloxacin as well as all the heavy metals and tetracycline were antagonistic. These results indicate that bacterial resistance to antibiotics can be affected by the type and concentration of co-exposed heavy metals and may further threaten people's health and ecological security severely via horizontal gene transfer.

AIM: ;To investigate the diversity of bacterial lactase genes in the intestinal contents of mice with antibiotics-induced diarrhea.;METHODS: ;Following 2 d of adaptive feeding, 12 specific pathogen-free Kunming mice were randomly divided into the control group and model group. The mouse model of antibiotics-induced diarrhea was established by gastric perfusion with mixed antibiotics (23.33 mL·kg;-1;·d;-1;) composed of gentamicin sulfate and cephradine capsules administered for 5 days, and the control group was treated with an equal amount of sterile water. Contents of the jejunum and ileum were then collected and metagenomic DNA was extracted, after which analysis of bacterial lactase genes using operational taxonomic units (OTUs) was carried out after amplification and sequencing.;RESULTS: ;OTUs were 871 and 963 in the model group and control group, respectively, and 690 of these were identical. There were significant differences in Chao1 and ACE indices between the two groups (;P; < 0.05). Principal component analysis, principal coordination analysis and nonmetric multidimensional scaling analyses showed that OTUs distribution in the control group was relatively intensive, and differences among individuals were small, while in the model group, they were widely dispersed and more diversified.