McDonald Lawrence Clifford
Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
J Travel Med. 2017 Apr 1;24(suppl_1):S35-S38. doi: 10.1093/jtm/taw084.
Antibiotics have profound and lasting effects on the lower intestinal (gut) microbiome that can both promote resistance and increase susceptibility to colonization and infection; knowledge of these changes is important to the prevention and treatment of traveler's diarrhea.
Recent data from epidemiologic and modern metagenomics studies were reviewed in regard to how such findings could inform the prevention and treatment of traveler's diarrhea.
Although it is well recognized that antibiotics increase the risk for Clostridium difficile infection, it is less recognized how they predispose patients to typically foodborne pathogens such as Salmonella or Camplyobacter spp. While these pathogens account for only a fraction of traveler's diarrhea, such predisposition reflects how antibiotic exposure that precedes or occurs during travel may increase the risk for infection with other more common pathogens, even possibly enterotoxigenic Eschericia coli, especially in the setting of acquired resistance. Even short antibiotic exposures disrupt the gut microbiome up to a year or more and repeated exposures appear to attenuate recovery from ever occurring. One bacterial phylum that commonly increases in the gut following antibiotics are the proteobacteria including Enterobacteriacea; these are pro-inflammatory and often carry antibiotic resistance genes, the number and diversity of these genes (i.e. the resistome) commonly expands following antibiotics. The gut resistome among healthy community-dwelling adults reflects geographic variability in antibiotic use practices in both humans and food-producing animals as well as possibly the transmission of antibiotic resistance genes through the food supply.
Because antibiotic use among travelers will influence the resistome and thereby promote geographic spread of resistance, it is important that antibiotic use recommendations for travelers be guided by resistance surveillance data as well as a careful assessment of the risks and benefits to both the individual and society.
抗生素对下肠道（肠道）微生物群有深远而持久的影响，既会促进耐药性，又会增加定植和感染的易感性；了解这些变化对于旅行者腹泻的预防和治疗很重要。
回顾了流行病学和现代宏基因组学研究的最新数据，以了解这些发现如何为旅行者腹泻的预防和治疗提供信息。
虽然人们普遍认识到抗生素会增加艰难梭菌感染的风险，但对于它们如何使患者易感染典型的食源性病原体，如沙门氏菌或弯曲杆菌属，却鲜为人知。虽然这些病原体仅占旅行者腹泻的一小部分，但这种易感性反映了旅行前或旅行期间接触抗生素可能如何增加感染其他更常见病原体的风险，甚至可能增加产肠毒素大肠杆菌的感染风险，尤其是在获得性耐药的情况下。即使是短期接触抗生素也会使肠道微生物群紊乱长达一年或更久，反复接触似乎会减弱恢复的可能性。抗生素使用后肠道中通常会增加的一个细菌门是变形菌门，包括肠杆菌科；这些细菌具有促炎作用，并且通常携带抗生素耐药基因，抗生素使用后这些基因的数量和多样性（即耐药基因组）通常会增加。健康社区成年人的肠道耐药基因组反映了人类和食用动物抗生素使用习惯的地理差异，以及抗生素耐药基因可能通过食物供应传播的情况。
由于旅行者使用抗生素会影响耐药基因组，从而促进耐药性的地理传播，因此旅行者抗生素使用建议应以耐药性监测数据以及对个人和社会的风险与益处的仔细评估为指导，这一点很重要。
