Evaluation of treatment and prophylaxis with nitrofurans and comparison with alternative antimicrobial agents in experimental Salmonella enterica Serovar enteritidis infection in chicks

The ability of the nitrofuran antimicrobial agents furazolidone and furaltadone to prevent, reduce or eliminate Salmonella enterica serovar enteritidis PT4 infection in artificially challenged day-old chicks was evaluated. Treating the birds with the nitrofurans failed to eliminate established infections with either furazolidone-resistant (Fz^R) or furazolidone-sensitive (Fz^S) strains. Simultaneous administration of the nitrofurans to day-old chicks challenged with Fz^S failed to prevent infection but reduced colonization significantly (p<0.05) compared to unmedicated controls. No reduction of colonization occurred with Fz^R. Challenging birds with Fz^S and simultaneous dosing with nitrofurans for 1 week, followed by a second week of continued treatment, resulted in an increase in the level of colonization in the second week rather than a decrease. Dosing with the nitrofurans (200 ppm) for 1 week prior to challenge with Fz and continued medication for a further week prevented colonization of the caecum, liver and spleen. However, cessation of dosing at the time of challenge with salmonella resulted in colonization. Chloramphenicol and tetracycline at concentrations of 200 ppm were both independently capable of preventing colonization by salmonella. Sulphadiazine initially reduced colonization but failed to eliminate the infection. Only when furazolidone was combined with chloramphenicol or when sulphadiazine was combined with trimethoprim, and the combined drugs were administered concurrently with the challenge, was colonization prevented.     

HPLC法检测饲料中4种硝基呋喃类药物

时饲料中四种硝基呋喃类药物呋喃西林(NFZ)、呋喃妥因(NFT)、呋喃它酮(FTD)和呋喃唑酮(FZD)的高效液相色谱(HPLC)检测方法进行了研究.采用50 mL乙腈于65℃下超声提取药物.经MCX固相萃取小柱净化后进行液相色谱-紫外检测,检测波长为370 nm对饲料进行10～500μg/g硝基呋喃类药物的添加回收实验,结果表明,4种药物的平均回收率为80.6%～99.9%(n=4),日内变异系数为0.68%～8.99%(n=4),日间变异系数为1.85%～8.44%(n=3).配合饲料中NFZ、NFT、FTD、FZD的检测限分别90、69、56μg/g和148 μg/g,定量限分别为180、137、112μg/g和296 μg/g;预混合饲料中NFZ、NFT、FTD、FZD的检测限分别为59、132、66μg/g和88 μg/g,定量限分别118、265、132μg/g和176μg/g.