Lenart J, Andersen A A, Rockey D D
Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA.
Antimicrob Agents Chemother. 2001 Aug;45(8):2198-203. doi: 10.1128/AAC.45.8.2198-2203.2001.
Tetracycline (TET) is a front-line antibiotic for the treatment of chlamydial infections in both humans and animals, and the emergence of TET-resistant (Tet(r)) Chlamydia is of significant clinical importance. Recently, several Tet(r) chlamydial strains have been isolated from swine (Sus scrofa) raised in production facilities in Nebraska. Here, the intracellular development of two Tet(r) strains, R19 and R27, is characterized through the use of tissue culture and immunofluorescence. The strains grow in concentrations of up to 4 microg of TET/ml, while a TET-sensitive (Tet(s)) swine strain (S45) and a strain of the human serovar L2 (LGV-434) grow in up to 0.1 microg of TET/ml. Although inclusions form in the presence of TET, many contain large aberrant reticulate bodies (RBs) that do not differentiate into infectious elementary bodies. The percentage of inclusions containing typical developmental forms decreases with increasing TET concentrations, and at 3 microg of TET/ml 100% of inclusions contain aberrant RBs. However, upon removal of TET the aberrant RBs revert to typical RBs, and a productive developmental cycle ensues. In addition, inclusions were found that contained both C. suis R19 and Chlamydia trachomatis L2 after sequential infection, demonstrating that two biologically distinct chlamydial strains could both develop within a single inclusion.
四环素（TET）是治疗人和动物衣原体感染的一线抗生素，耐四环素（Tet(r)）衣原体的出现具有重要的临床意义。最近，在内布拉斯加州养殖设施中饲养的猪（Sus scrofa）中分离出了几种耐四环素衣原体菌株。在此，通过组织培养和免疫荧光对两种耐四环素菌株R19和R27的细胞内发育进行了表征。这些菌株能在高达4微克/毫升的四环素浓度下生长，而一株对四环素敏感（Tet(s)）的猪菌株（S45）和一株人血清型L2菌株（LGV - 434）只能在高达0.1微克/毫升的四环素浓度下生长。尽管在四环素存在的情况下会形成包涵体，但许多包涵体含有大量异常的网状体（RB），这些网状体不会分化为有感染性的原体。含有典型发育形式的包涵体百分比随着四环素浓度的增加而降低，在3微克/毫升的四环素浓度下，100%的包涵体含有异常的网状体。然而，去除四环素后，异常的网状体会恢复为典型的网状体，并随之进入一个有效的发育周期。此外，在顺序感染后发现了同时含有猪衣原体R19和沙眼衣原体L2的包涵体，这表明两种生物学上不同的衣原体菌株可以在单个包涵体内发育。
