Guan J, Wasty A, Grenier C, Chan M
Ottawa Laboratory-Fallowfield, Canadian Food Inspection Agency, Nepean, Ontario, Canada.
Poult Sci. 2007 Apr;86(4):610-3. doi: 10.1093/ps/86.4.610.
The aim of this study was to determine if mobile plasmids carrying antibiotic-resistant genes could survive and be transferred in chicken manure maintained under conditions similar to those found in commercial cage layer operations and during composting. Escherichia coli J5 harboring a self-transmissible plasmid (RP4) and E. coli C600 harboring a mobile plasmid (pIE723) were used as plasmid donors; E. coli CV601 was used as a plasmid recipient. At 23 degrees C both plasmids were transferred to E. coli CV601 in chicken manure and in compost microcosms that consisted of a mixture of chicken manure and peat. The transfer frequencies ranged from 8.1 x 10(-5) to 2.4 x 10(-3) per donor cell in manure and from 2.4 x 10(-5) to 5.5 x 10(-4) per donor cell in compost microcosms. After 45 d of incubation at 23 degrees C, RP4, but not pIE723, was recovered by an exogenous isolation method although their E. coli hosts were not cultured from the microcosms. However, when the temperatures of the compost microcosms were elevated to 50 degrees C or above, neither the plasmids nor their E. coli hosts could be detected. The results suggested that composting of chicken manure at high temperatures could help prevent the spread of antibiotic-resistant genes via plasmids in the environment.
本研究的目的是确定携带抗生素抗性基因的移动质粒在类似于商业笼养蛋鸡场的条件下保存的鸡粪中以及堆肥过程中能否存活并转移。携带自我传递质粒（RP4）的大肠杆菌J5和携带移动质粒（pIE723）的大肠杆菌C600用作质粒供体；大肠杆菌CV601用作质粒受体。在23摄氏度时，两种质粒都能在鸡粪中和由鸡粪与泥炭混合而成的堆肥微宇宙中转导至大肠杆菌CV601。在鸡粪中，每个供体细胞的转移频率范围为8.1×10⁻⁵至2.4×10⁻³，在堆肥微宇宙中为2.4×10⁻⁵至5.5×10⁻⁴。在23摄氏度下培养45天后，尽管未从微宇宙中培养出它们的大肠杆菌宿主，但通过外源分离方法回收了RP4，而未回收pIE723。然而，当堆肥微宇宙的温度升高到50摄氏度或更高时，既检测不到质粒，也检测不到它们的大肠杆菌宿主。结果表明，高温堆肥鸡粪有助于防止抗生素抗性基因通过质粒在环境中传播。
