Anti-Tetracycline polyclonal antibody

An ultrahigh-sensitivity lateral flow immunochromatography (LFIC) assay based on up-converting nanoparticles (UCNPs) was developed to carry out a multi-residue detection of tetracycline in milk. The sensitivity of the immunoassay was greatly improved by the use of a broad-spectrum monoclonal antibody attached to UCNPs to form a signal probe. Under the optimal conditions, the UCNP-LFIC assay enabled sensitive detection of tetracycline (TC) as well as of oxytetracycline (OTC), chlortetracycline (CTC), and doxycycline (DOX) within 10 min, withIC(50)values of 0.32, 0.32, 0.26, 0.22 ng/mL, respectively. There was no cross-reactivity with ten other antibiotics. Similarly, we evaluated the experimental results for matrix effects. Experiments involving spiking showed the four tetracycline antibiotics displaying mean recoveries ranging from 93.95 to 111.90% with relative standard deviations (RSDs) of < 9.95%. The detection results of actual samples using the developed method showed a good correlation (R-2 >= 0.98) with the results using high-performance liquid chromatography (HPLC). Thus, the assay can achieve an ultrahighly sensitive detection of antibiotics in milk, and can hence promote human health and provides promising applications in the bio-detection field.

The objective of this study was to estimate the fecal carriage of Salmonella spp. among culled adult dairy cows presented to an abattoir in Wuhan, China and to evaluate their antimicrobial resistance profiles. Rectal swabs from 138 culled cows were cultured. Laboratory analysis involved the identification of Salmonella, the susceptibility assessment and the presence of Extended Spectrum beta-lactamases and mcr genes in the isolates. An overall prevalence of Salmonella of 29.0% was recorded with 63.4% (26/41) and 2.4% (1/41) of the isolates identified as S. Typhimurium and S. Dublin, respectively. The occurrence of Salmonella was higher (odd ratios: 3.3) in culled cows originating from the northeast zone of China than cows originating from the central and north zones. Twenty multi-drug resistant strains (resistant to three or more antimicrobial agents) were detected (48.8%) and overall, a high resistance to ampicillin (36/41) and tetracycline (15/41) was observed. Extended Spectrum beta-lactamases phenotypes were found in 7/41 isolates, of which all contained the bla(CTX-M) resistance gene, and no mcr genes were found by polymerase chain reaction. The high prevalence of Salmonella fecal carriage and antimicrobial resistance may contribute to an increased risk of Salmonella transmission to food.