Abstract：
OBJECTIVE: The emergence of the florfenicol resistance gene fexA in Campylobacter poses a serious threat to public health, but the extent of the spread of fexA in Campylobacter from various hosts has not been well understood. This study aimed to investigate the fexA in Campylobacter isolates from different hosts.
METHODS: PCR was used to identify fexA-positive Campylobacter from different hosts during 2008-2019 in China, and the fexA-positive isolates were characterized by susceptibility tests, whole-genome sequencing, and natural transformation.
RESULTS: A total of 69 (2.54%, 69/2721) fexA-positive Campylobacter were identified, and the fexA-positive isolates increased remarkably (0.42%-16.90%) since it was first detected in 2010. By source, the 69 isolates were obtained from chickens (3.57%, 57/1595), geese (3.43%, 7/204), ducks (1.02%, 2/197), and environments (2.86%, 3/105); the fexA-positive isolates were not isolated in humans and pigs. In addition to fexA, these isolates also carried other antimicrobial resistance genes and exhibited multidrug resistance. Whole-genome sequencing analysis showed the fexA gene can disseminate clonally or horizontally via either multidrug resistance genomic islands or insertion sequences among the Campylobacter. The genetic structure IS1216-∆ISEfa11-hp-fexA-NAD(P)H-∆ISEfa11-IS1216 was conserved and widespread in the Campylobacter of various origins, and the IS1216 can form fexA-carrying circular intermediates, emphasizing that IS1216 plays an important role in the spread of fexA in Campylobacter.
CONCLUSIONS: This study indicates the wide spread of fexA-positive Campylobacter in poultry and environments. Because multidrug resistance genomic islands and IS1216 can facilitate the transmission of fexA, systematic surveillance should be implemented to prevent the spread of fexA to humans.
METHODS: PCR was used to identify fexA-positive Campylobacter from different hosts during 2008-2019 in China, and the fexA-positive isolates were characterized by susceptibility tests, whole-genome sequencing, and natural transformation.
RESULTS: A total of 69 (2.54%, 69/2721) fexA-positive Campylobacter were identified, and the fexA-positive isolates increased remarkably (0.42%-16.90%) since it was first detected in 2010. By source, the 69 isolates were obtained from chickens (3.57%, 57/1595), geese (3.43%, 7/204), ducks (1.02%, 2/197), and environments (2.86%, 3/105); the fexA-positive isolates were not isolated in humans and pigs. In addition to fexA, these isolates also carried other antimicrobial resistance genes and exhibited multidrug resistance. Whole-genome sequencing analysis showed the fexA gene can disseminate clonally or horizontally via either multidrug resistance genomic islands or insertion sequences among the Campylobacter. The genetic structure IS1216-∆ISEfa11-hp-fexA-NAD(P)H-∆ISEfa11-IS1216 was conserved and widespread in the Campylobacter of various origins, and the IS1216 can form fexA-carrying circular intermediates, emphasizing that IS1216 plays an important role in the spread of fexA in Campylobacter.
CONCLUSIONS: This study indicates the wide spread of fexA-positive Campylobacter in poultry and environments. Because multidrug resistance genomic islands and IS1216 can facilitate the transmission of fexA, systematic surveillance should be implemented to prevent the spread of fexA to humans.
摘要：
目的:弯曲菌中氟苯尼考耐药基因fexA的出现对公众健康构成严重威胁,但是fexA在各种宿主弯曲杆菌中的传播程度尚未得到很好的理解。本研究旨在研究不同宿主的弯曲杆菌中的fexA。
方法：在2008-2019年期间，在中国使用PCR鉴定来自不同宿主的fexA阳性弯曲杆菌，fexA阳性的菌株通过药敏试验进行了表征，全基因组测序，自然转化。
结果：总计69（2.54％，69/2721)确定了fexA阳性弯曲杆菌，fexA阳性分离株自2010年首次检测以来显著增加(0.42-16.90%)。按来源,69株分离株来自鸡(3.57%，57/1595），鹅(3.43%，7/204),鸭子（1.02%，2/197),和环境(2.86%，3/105),而fexA阳性分离株没有在人和猪中分离。除了fexA,这些分离株还携带其他抗菌素耐药基因，并表现出多重耐药性。全基因组测序分析表明，fexA基因可以通过多药耐药基因组岛或弯曲杆菌之间的插入序列克隆或水平传播。遗传结构IS1216-ΔISEfa11-hp-fexA-NAD（P）H-ΔISEfa11-IS1216在各种起源的弯曲杆菌中保守并广泛存在，IS1216可以形成携带fexA的环状中间体，强调IS1216在fexA在弯曲杆菌中的传播中起着重要作用。
结论：本研究表明fexA阳性弯曲杆菌在家禽和环境中普遍存在。由于MDRGI和IS1216可以促进fexA的传输，应实施系统监测，以防止fexA传播给人类。
方法：在2008-2019年期间，在中国使用PCR鉴定来自不同宿主的fexA阳性弯曲杆菌，fexA阳性的菌株通过药敏试验进行了表征，全基因组测序，自然转化。
结果：总计69（2.54％，69/2721)确定了fexA阳性弯曲杆菌，fexA阳性分离株自2010年首次检测以来显著增加(0.42-16.90%)。按来源,69株分离株来自鸡(3.57%，57/1595），鹅(3.43%，7/204),鸭子（1.02%，2/197),和环境(2.86%，3/105),而fexA阳性分离株没有在人和猪中分离。除了fexA,这些分离株还携带其他抗菌素耐药基因，并表现出多重耐药性。全基因组测序分析表明，fexA基因可以通过多药耐药基因组岛或弯曲杆菌之间的插入序列克隆或水平传播。遗传结构IS1216-ΔISEfa11-hp-fexA-NAD（P）H-ΔISEfa11-IS1216在各种起源的弯曲杆菌中保守并广泛存在，IS1216可以形成携带fexA的环状中间体，强调IS1216在fexA在弯曲杆菌中的传播中起着重要作用。
结论：本研究表明fexA阳性弯曲杆菌在家禽和环境中普遍存在。由于MDRGI和IS1216可以促进fexA的传输，应实施系统监测，以防止fexA传播给人类。
