Comparative mutagenicity testing of ceftiofur sodium. II. Cytogenetic damage induced in vitro by ceftiofur is reversible and is due to cell cycle delay

Cytotoxicity and degradation product identification of thermally treated ceftiofur

Ceftiofur (CEF) is a cephalosporin antibiotic and is a commonly used drug in animal food production. As a heat-labile compound, the residual CEF toxicity after thermal treatment has rarely been reported. This study was to investigate the potential toxicity of thermally treated CEF and determine the toxic components. By cytotoxicity tests and liquid chromatography-mass spectrometry (LC-MS) assays, the cytotoxicity of the thermally treated CEF (TTC) and the components of TTC was identified, respectively. Our results showed that TTC exhibited significantly increased toxicity compared with CEF towards LO2 cells by inducing apoptosis. Through LC-MS assays, we identified that the toxic compound of TTC was CEF-aldehyde (CEF-1). The IC₅₀ value of CEF-1 on LO2 cells treated for 24 h was 573.1 μg mL⁻¹, approximately 5.3 times lower than CEF (3052.0 μg mL⁻¹) and 3.4 times lower than TTC (1967.0 μg mL⁻¹). Moreover, we found that CEF-1 was also present in thermally treated desfuroylceftiofur (DFC), the primary metabolite of CEF, indicating that residual CEF or DFC could produce CEF-1 during the heating process. These findings suggest that CEF-1 is a newly identified toxic compound, and CEF-1 may pose a potential threat to food safety or public health.

Ceftiofur (CEF) is a cephalosporin antibiotic and is a commonly used drug in animal food production. This study investigated the cytotoxicity of thermally treated CEF.

Could contaminant induced mutations lead to a genetic diversity overestimation?

Contaminant driven genetic erosion reported through the inspection of selectable traits can be underestimated using neutral markers. This divergence was previously reported in the aquatic system of an abandoned pyrite mine. The most sensitive genotypes of the microcrustacean cladoceran Daphnia longispina were found to be lacking in the impacted reservoir near the entrance of the metal rich acid mine drainage (AMD). Since that divergence could be, at least partially, accounted for by mutagenicity and genotoxicity of the AMD, the present study aimed at providing such a characterization. The Allium cepa chromosomal aberration assay, using root meristematic cells, was carried out, by exposing seeds to 100, 10, 1, and 0.1 % of the local AMD. Chromosomal aberrations, cell division phases and cell death were quantified after the AMD exposure and after 24 and 48 h recovery periods. The AMD revealed to be mutagenic and genotoxic, even after diluting it to 1 and 0.1 %. Dilutions within this range were previously found to be below the lethality threshold and to elicit sublethal effects on reproduction of locally collected D. longispina clonal lineages Significant mutagenic effects (micronuclei and chromosomal breaks) were also found at 0.1 % AMD, supporting that exposure may induce permanent genetic alterations. Recovery tests showed that AMD genotoxic effects persisted after the exposure.