Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center and Weill Cornell Medicine, New York, New York;, Email:
Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan Kettering Cancer Center, Weill Cornell Medicine, The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan Kettering Cancer Center and Weill Cornell Medicine, New York, New York.
J Am Assoc Lab Anim Sci. 2023 Mar 1;62(2):131-138. doi: 10.30802/AALAS-JAALAS-22-000105. Epub 2023 Feb 6.
Infectious agents have varying susceptibilities to thermal inactivation and/or mechanical removal from cages by the use of heated, pressurized water. In this study, we tested whether 5 specific infectious organisms ( [segmented filamentous bacterium (SFB)], sp., mouse norovirus (MNV), sp., and ) could survive the cage wash process and still infect naïve mice. These 5 organisms were chosen due to their prevalence in rodent colonies, environmental stability, and/or potential to influence experimental outcomes. Cages that had housed mice shedding all 5 organisms were assigned to 1 of 3 treatment groups: 1) sanitization in a tunnel washer followed by autoclaving (121 °C [250 °F] for 20 min; = 40 cages); 2) sanitization in a tunnel washer (82 °C [180 °F] for an average of 30 s; = 40 cages); or 3) control (bedding change only; = 40 cages). The presence of these agents in the cage was assessed by performing PCR on swabs of the empty soiled cage interior before and after the treatment. In addition, to determine if any residual nucleic acid was infectious, 2 Swiss outbred (J:ARC(S)) female mice were housed for 7 d in cages from each treatment group. The above procedures were then repeated so that every week each pair of J:ARC(S) mice ( = 10 pairs of mice/treatment group) were housed in another cage that underwent the same treatment; this was done for a total of 4 consecutive, 1-wk-long periods. Swabs collected from soiled cages were PCR-positive for SFB, , MNV, , and in 99%, 97%, 39%, 63%, and 73% of the cages tested, respectively. Cages in the tunnel wash group that were PCR-positive for SFB, , , and before treatment remained PCR-positive in 8%, 15%, 43%, and 10% of positive cages, respectively. None of the cages from the autoclave group were PCR-positive for any of the agents after treatment. None of the mice housed in cages in either the autoclave or tunnel wash groups became infected with any of the agents. However, 80%, 60%, and 100% of the pairs of mice housed in untreated cages were PCR-positive for SFB, MNV, and , respectively. None of the mice housed in untreated cages were positive for or . Our results suggest that nucleic acids from these bacterial and protozoal organisms may remain in cages after mechanical cage washing, but these nucleic acids are not infectious, and autoclaving is not necessary to prevent transmission.
病原体对热失活和/或通过使用加热加压水从笼子中机械去除的敏感性各不相同。在这项研究中，我们测试了 5 种特定的感染性生物体（[分段丝状菌（SFB）]，sp.，小鼠诺如病毒（MNV），sp.，和）是否能够在笼洗过程中存活下来并仍然感染天真的小鼠。选择这 5 种生物体是因为它们在啮齿动物群体中的普遍性、环境稳定性和/或对实验结果的潜在影响。饲养有 5 种生物体的笼子被分配到 3 个治疗组之一：1）隧道清洗器中的消毒，然后进行高压灭菌（121°C[250°F]，20 分钟；= 40 个笼子）；2）隧道清洗器中的消毒（82°C[180°F]，平均 30 秒；= 40 个笼子）；或 3）对照（仅更换床上用品；= 40 个笼子）。在处理前后，通过对空污笼内的拭子进行 PCR 检测，评估这些生物体在笼子中的存在。此外，为了确定任何残留的核酸是否具有传染性，2 只瑞士近交系（J：ARC（S））雌性小鼠在每个治疗组的笼子中饲养 7 天。然后重复上述程序，使每对 J：ARC（S）小鼠（= 10 对小鼠/治疗组）每周在另一个接受相同处理的笼子中饲养；这总共进行了 4 个连续的 1 周长的周期。从污染笼子中收集的拭子在 SFB、、MNV、、和的 PCR 检测中分别为 99%、97%、39%、63%和 73%的笼子呈阳性。在治疗前 SFB、、、和的 PCR 检测呈阳性的隧道清洗组的笼子中，阳性笼子的分别为 8%、15%、43%和 10%。经过高压灭菌处理后，任何一组笼子的 PCR 检测均未检测到任何一种病原体。在高压灭菌或隧道清洗组中饲养的小鼠均未感染任何一种病原体。然而，未处理笼子中饲养的 80%、60%和 100%的对小鼠的 SFB、MNV 和的 PCR 检测均呈阳性。未处理笼子中的任何小鼠对或呈阳性。我们的结果表明，这些细菌和原生动物生物体的核酸可能在机械笼洗后仍留在笼子中，但这些核酸没有传染性，并且不需要高压灭菌来防止传播。
