Horizontal gene transfer is the major driver of antimicrobial resistance in Salmonella enterica serovar Heidelberg

The reported increase in antibiotic-resistant bacteria in humans has resulted in a major shift away from antibiotic use in food animal production. This shift has been driven by the assumption that removing antibiotics will select for antibiotic susceptible bacterial taxa, which in turn will allow the currently available antibiotic arsenal to be more effective. This change in practice has highlighted new questions that need to be answered to assess the effectiveness of antibiotic removal in reducing the spread of antibiotic resistance bacteria. This research demonstrates that antibiotic-susceptible Salmonella enterica serovar Heidelberg strains can acquire multidrug resistance from commensal bacteria present in the gut of neonatal broiler chicks, even in the absence of antibiotic selection. We demonstrate that exposure to acidic pH drove the horizontal transfer of antimicrobial resistance plasmids and suggest that simply removing antibiotics from food animal production might not be sufficient to limit the spread of antimicrobial resistance.

人类中抗生素耐药菌增加的报道，导致食品动物生产中抗生素使用的重大转变。这一转变源于去除抗生素将选择耐药细菌群落的假设，进而使得现有的抗生素武器库能够更加有效。这种实践的变化突显了需要解答的新问题，以评估去除抗生素在减少抗生素耐药菌传播方面的有效性。本研究表明，易感沙门氏菌血清型海德尔堡菌株可以从新生肉鸡肠道中存在的共生菌中获取多药耐药性，即使在缺乏抗生素选择的情况下。我们证明，酸性pH值诱导了抗菌耐药性质粒的水平转移，并建议仅从食品动物生产中去除抗生素可能不足以限制抗菌耐药性的传播。