Two Actinobacillus pleuropneumoniae isolates from clinical cases of porcine pleuropneumonia in Japan were positive in the capsular serovar 15–specific PCR assay, but nontypeable (NT) in the agar gel precipitation (AGP) test. Nucleotide sequence analysis of gene clusters involved in the biosynthesis of capsular polysaccharide (CPS) and lipopolysaccharide O-polysaccharide (O-PS) revealed that both clusters contained transposable element ISApl1 of A. pleuropneumoniae belonging to the IS30 family. Immunoblot analysis revealed that these 2 isolates could not produce O-PS. We conclude that the ISApl1 of A. pleuropneumoniae can interfere in the biosynthesis of both CPS and O-PS.

来自日本猪胸膜肺炎临床病例的两种胸膜肺炎放线杆菌在荚膜血清15特异性PCR检测中呈阳性，但在琼脂凝胶沉淀（AGP）试验中未分型（NT）。参与荚膜多糖的生物合成的基因簇的核苷酸序列分析（CPS）和脂多糖O-多糖（O-PS）表明两个群集包含转座元件IS APL1的A.胸膜肺炎属于IS30家庭。免疫印迹分析显示这两个分离株不能产生O-PS。我们的结论是IS APL1的A.胸膜肺炎可以同时在CPS和O-PS的合成干扰。