Objective

Epidemic methicillin-resistant Staphylococcus aureus (MRSA) clones have been described in Ghana, but so far, no typical livestock-associated MRSA isolates (CC398) have been found. In this study we provide baseline information on antimicrobial resistance, population structure, and virulence gene content of S. aureus isolates from livestock and farm attendants.

Methods

Nasal samples were collected from cattle, pigs, goats, sheep, and farm attendants from three farms. Staphylococcus aureus was identified by matrix-assisted laser desorption/ionisation time-of-flight and antimicrobial susceptibility testing was performed using VITEK II (Biomerieux, Marcy l'Etoile, France) and interpreted according to EUCAST guidelines. Whole-genome sequencing was performed using the Illumina, San Diego, CA, USA MiSeq Platform.

Results

In total, 401 nasal swab samples were obtained from 57 farm attendants, 208 pigs, 30 goats, 26 sheep, and 80 cattle. The S. aureus isolates (n = 25) recovered (farm attendants: n = 10; pigs: n = 8; and goats: n = 7) were frequently resistant to penicillin (68%), tetracycline (44%), and ciprofloxacin (32%); two human isolates were MRSA. Twelve isolates (48%) were multidrug resistant (MDR) (>3 classes). Genome sequencing of the isolates revealed ST152-t355, ST9-t1430, and ST133-t8662 as dominant clones among farm attendants, pigs, and goats, respectively. The two MRSA isolates detected belonged to ST8-t334 and ST152-t355. The scn and sak genes associated with human-adaption were detected in 10 isolates; 9 from humans and 1 from a goat. Typing results provided evidence of a single potential transmission event (t861, PVL-, scn+).

Conclusion

No MRSA was detected among livestock, perhaps because of low intensive farming; however, the relatively high prevalence of MDR isolates may be a result of inappropriate antibiotic usage in Ghanaian livestock production.

中文翻译：

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加纳牲畜和农场从业人员对抗生素耐药的金黄色葡萄球菌分离株的全基因组序列分析。

目的

加纳已经描述了耐甲氧西林流行的金黄色葡萄球菌（MRSA）克隆，但到目前为止，尚未发现典型的与牲畜相关的MRSA分离株（CC398）。在这项研究中，我们提供了有关来自牲畜和农场服务员的金黄色葡萄球菌分离物的抗药性，种群结构和毒力基因含量的基线信息。

方法

鼻样本采集自三个农场的牛，猪，山羊，绵羊和农场服务员。通过基质辅助激光解吸/电离飞行时间鉴定金黄色葡萄球菌，并使用VITEK II（Biomerieux，Marcy l'Etoile，法国）进行抗菌药敏试验，并根据EUCAST指南进行解释。使用美国加利福尼亚州圣地亚哥的Illumina MiSeq平台进行全基因组测序。

结果

总共从57名农场服务员，208头猪，30只山羊，26只绵羊和80头牛中获得了401份鼻拭子样本。的金黄色葡萄球菌分离株（Ñ = 25）中回收（农场服务员：Ñ = 10;猪：Ñ = 8;和山羊：Ñ = 7）对青霉素（68％），四环素（44％），和环丙沙星耐频繁（32％）；两个人类分离株是MRSA。十二个分离株（48％）具有多重耐药性（MDR）（> 3类）。分离株的基因组测序表明，ST152-t355，ST9-t1430和ST133-t8662分别是农场服务员，猪和山羊中的优势克隆。检测到的两个MRSA分离株属于ST8-t334和ST152-t355。在SCN和SAK在10个菌株中检测到与人类适应相关的基因；人类取9个，山羊取1个。打字结果提供了单个潜在传播事件（t861，PVL-，scn +）的证据。

结论

在牲畜中未检测到MRSA，可能是由于低集约化耕作。但是，MDR分离株的相对较高的流行率可能是加纳牲畜生产中抗生素使用不当的结果。