Schwarz Stefan, Kehrenberg Corinna, Salmon Sarah A, Watts Jeffrey L
Institut für Tierzucht der Bundesforschungsanstalt für Landwirtschaft (FAL), Höltystrasse 10, 31535 Neustadt-Mariensee, Germany.
J Antimicrob Chemother. 2004 Feb;53(2):379-82. doi: 10.1093/jac/dkh059. Epub 2004 Jan 16.
Prior to the renewal of spectinomycin licensing for veterinary uses in Germany, 154 Pasteurella multocida and 148 Mannheimia haemolytica strains from respiratory tract infections in cattle were investigated for their MICs of spectinomycin and other antimicrobial agents. The data obtained should serve as a baseline from which to judge the future development of resistance. Moreover, the in vitro activity of spectinomycin in comparison with other antimicrobials should be assessed.
MIC determination for all 302 strains was performed by the broth dilution method and evaluated according to NCCLS standards. MIC(50) and MIC(90) values were calculated. Strains resistant to spectinomycin were subjected to PCR assays for genes known to mediate spectinomycin resistance in Gram-negative and Gram-positive bacteria.
With the exception of resistance to sulfamethoxazole in P. multocida and M. haemolytica, and resistance to ampicillin in M. haemolytica, an overall low level of resistance was detected. A total of 93.5% of the P. multocida and 98.6% of the M. haemolytica strains were susceptible to spectinomycin, with MIC(90)s of 32 mg/L. PCR analysis showed that none of the spectinomycin-resistant strains carried any of the aadA gene subtypes, nor the genes spc or aad(9).
Prior to the renewal of spectinomycin, only a small number of spectinomycin-resistant strains was detected among bovine P. multocida and M. haemolytica. The genes responsible for spectinomycin resistance in these strains seemed to be different from those so far known to occur in other Gram-negative and Gram-positive bacteria.
在德国重新发放大观霉素用于兽医用途的许可证之前，对从牛呼吸道感染中分离出的154株多杀巴斯德菌和148株溶血曼氏杆菌进行了大观霉素及其他抗菌药物的最低抑菌浓度（MIC）检测。所获得的数据应作为判断未来耐药性发展的基线。此外，还应评估大观霉素与其他抗菌药物相比的体外活性。
采用肉汤稀释法对所有302株菌株进行MIC测定，并根据美国国家临床实验室标准委员会（NCCLS）标准进行评估。计算MIC50和MIC90值。对大观霉素耐药的菌株进行PCR检测，以检测已知介导革兰氏阴性菌和革兰氏阳性菌对大观霉素耐药的基因。
除多杀巴斯德菌和溶血曼氏杆菌对磺胺甲恶唑耐药，以及溶血曼氏杆菌对氨苄西林耐药外，总体耐药水平较低。总共93.5%的多杀巴斯德菌和98.6%的溶血曼氏杆菌菌株对大观霉素敏感，MIC90为32 mg/L。PCR分析表明，所有大观霉素耐药菌株均未携带任何aadA基因亚型，也未携带spc或aad(9)基因。
在重新发放大观霉素许可证之前，在牛多杀巴斯德菌和溶血曼氏杆菌中仅检测到少数大观霉素耐药菌株。这些菌株中导致大观霉素耐药的基因似乎与迄今已知在其他革兰氏阴性菌和革兰氏阳性菌中出现的基因不同。
