Widespread distribution of disinfectant resistance genes among staphylococci of bovine and caprine origin in Norway
Widespread distribution of disinfectant resistance genes among staphylococci of bovine and caprine origin in Norway
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DOI：
10.1128/jcm.43.9.4363-4368.2005
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发表时间：
2005-09-01
影响因子：
9.4
通讯作者：
Heir, E
中科院分区：
文献类型：
--
作者：
Bjorland, J;Steinum, T;Heir, E
我们在这里展示了127个奶牛群和70个奶山羊群的未经巴氏灭菌的牛奶中葡萄球菌对季铵化合物(QAC)的外排抗性基因的广泛分布。在21%的牛群(qacA/B、SMR、qacG和qacJ)和10%的山羊群(qacA/B和SMR)中发现了qac抗性基因。4种凝固酶阴性葡萄球菌(CONS)中检出qacA/B(12株)，8种CONS中检出SMR(27株)，金黄色葡萄球菌中检出2株qacG(PNVH99)，科氏葡萄球菌和华纳葡萄球菌中检出qacG(2株)，人葡萄球菌和德尔菲尼葡萄球菌(PNVH01)中检出2株qacG。从一群奶牛的罐奶和乳季乳样品中分离出难以区分的脉冲场凝胶电泳(PFGE)cons类型，表明这些耐QAC葡萄球菌来自乳房内。在不同的牛群中观察到了难以区分或密切相关的牛QAC抗性CON的PFGE类型。一种特殊的牛华纳沙门氏菌PFGE类型被反复从一个牛群30个月期间收集的样本中分离出来，显示出长期的持久性。总之，携带QAC耐药基因的葡萄球菌在挪威奶牛和山羊群中的广泛分布似乎是QAC耐药质粒种内和种间传播以及QAC耐药株克隆性传播的结果。
We demonstrate here a widespread distribution of genes mediating efflux-based resistance to quaternary ammonium compounds (QACs) in staphylococci from unpasteurized milk from 127 dairy cattle herds and 70 dairy goat herds. QAC resistance genes were identified in 21% of the cattle herds (qacA/B, smr, qacG, and qacJ) and in 10% of the goat herds (qacA/B and smr). Further examination of 42 QAC-resistant bovine and caprine isolates revealed the following genes: qacA/B (12 isolates) was present in four different species of coagulase-negative staphylococci (CoNS), smr (27 isolates) was detected in eight different CoNS species and in Staphylococcus aureus on a previously reported plasmid (pNVH99), qacG (two isolates) was detected on two plasmids (pST94-like) in Staphylococcus cohnii and Staphylococcus warneri, and qacJ (two isolates) was found in Staphylococcus hominis and Staphylococcus delphini on a plasmid (pNVH01) previously found in equine staphylococci. Isolation of indistinguishable pulsed-field gel electrophoresis (PFGE) CoNS types from tank milk and mammary quarter milk samples in a dairy cattle herd suggested that these QAC-resistant staphylococci were of intramarnmary origin. Indistinguishable or closely related PFGE types of bovine QAC-resistant CoNS were observed in different herds. One particular bovine S. warneri PFGE type was isolated repeatedly from samples collected during a 30-month period in a herd, showing long-term persistence. In conclusion, it seems that the widespread distribution of staphylococci carrying QAC resistance genes in Norwegian dairy cattle and goat herds is the result of both the intra- and interspecies spread of QAC resistance plasmids and the clonal spread of QAC-resistant strains.