Introduction

Anaplasma sp. is an obligatory intracellular Gram-negative tick-transmitted bacterial pathogen of humans and animals. Oxytetracycline and chlortetracycline are the drugs of choice for treating domestic animals with acute anaplasmosis. Lack of documented information about oxytetracycline resistance in Anaplasma species in the world was the scope of this study to screen by PCR for the detection of the oxytetracycline-resistance genes in Anaplasma species from infected cattle and sheep in the Northwest and Southwest of Iran.

Materials and Methods

Total of 100 cattle and sheep blood samples collected from 2 provinces in the Northwest and 1 province in the Southwest of Iran were tested microscopically by the Giemsa staining examination and confirmed by PCR. Then the presence of two different oxytetracycline-resistance genes (otrA, and otrB) was detected by PCR in positive samples.

Results

The results showed that 60% of Anaplasma-infected samples were identified to have an otrA-resistance gene, and 26.67% had an otrB-resistance gene. The coexistence of two oxytetracycline-resistance determinants was encountered in 13.33% of the isolates. The significant difference in the frequency of otr genes was found among three Anaplasma species (A. marginale, A. centrale and A. ovis), and among three studied regions in Iran (p < 0.05). The identified sequences were submitted to the GenBank and deposited under accession numbers MN880729 and MN895439 for otrB and otrA genes.

Conclusion

This study, for the first time, indicated the oxytetracycline-resistance genes in the three most prevalent Anaplasma species in ruminants. This finding helps to select an appropriate treatment strategy for eradication of anaplasmosis.

中文翻译：

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无浆体物种中土霉素抗性基因存在和分布的首次调查

介绍

无形体属。是人类和动物的必需细胞内革兰氏阴性蜱传播细菌病原体。土霉素和金霉素是治疗家畜急性无形体病的首选药物。缺乏世界上无浆体物种中土霉素抗性的文献信息是本研究的范围，以通过 PCR 筛选检测伊朗西北部和西南部受感染牛和羊的无形体物种中的土霉素抗性基因。

材料和方法

对伊朗西北部2个省和西南1个省共采集的100份牛羊血样进行吉姆萨染色镜检，PCR证实。然后通过 PCR 在阳性样品中检测到两种不同的土霉素抗性基因（otrA和otrB）的存在。

结果

结果表明，60% 的无形体感染样本被鉴定为具有otrA抗性基因，26.67% 具有otrB抗性基因。在 13.33% 的分离株中遇到了两种土霉素抗性决定簇的共存。otr基因频率的显着差异在三种无形体物种（A.边缘、A.centrale和A.ovis）和伊朗的三个研究区域之间发现（p  < 0.05）。鉴定的序列被提交给 GenBank 并以登记号 MN880729 和 MN895439 存放于otrB和otrA基因。

结论

这项研究首次表明了反刍动物中三种最普遍的无形体物种中的土霉素抗性基因。这一发现有助于选择合适的治疗策略来根除无形体病。