Abstract：
Bacitracin is an antimicrobial used in the feed or water of poultry in the U.S. for the prevention, treatment, and control of clostridial diseases such as necrotic enteritis. Concern has been raised that bacitracin can select for antimicrobial-resistant bacteria that can be transmitted to humans and subsequently cause disease that is more difficult to treat because of the resistance. The objective of the present study was to perform a quantitative risk assessment (QRA) to estimate the potential risk in the U.S. of human infection with antimicrobial-resistant Enterococcus faecalis and E. faecium derived from chicken and turkey products as a result of bacitracin usage in U.S. poultry. The modeling approach estimated the annual number of healthcare-associated enterococcal infections in the U.S. that would be resistant to antimicrobial therapy and that would be derived from poultry sources because of bacitracin use in poultry. Parameter estimates were developed to be \"maximum risk\" to overestimate the risk to humans. While approximately 60% of E. faecalis and E. faecium derived from poultry were predicted to possess bacitracin resistance based on the presence of the bcrABDR gene locus, very few human-derived isolates possessed this trait. Furthermore, no vancomycin or linezolid-resistant strains of E. faecalis or E. faecium were detected in poultry sources between the years 2002 and 2019. The model estimated the number of antimicrobial-resistant E. faecalis and E. faecium cases per year that might resist therapy due to bacitracin use in poultry as 0.86 and 0.14, respectively, which translates to an annual risk estimate for E. faecalis of less than 1 in 350 million and for E. faecium of less than 1 in 2 billion for members of the U.S. population. Even with the use of risk-maximizing assumptions, the results indicate that there is a high probability that the use of bacitracin according to label instructions in U.S. poultry presents a negligible risk to human health.
摘要：
杆菌肽是在美国家禽的饲料或水中用于预防的抗菌剂，治疗,和控制梭菌疾病，如坏死性肠炎。人们担心杆菌肽可以选择抗微生物药物抗性细菌，这些细菌可以传播给人类，随后导致由于耐药性而更难治疗的疾病。本研究的目的是进行定量风险评估（QRA），以估计美国家禽使用杆菌肽后，由鸡肉和火鸡产品产生的耐药性粪肠球菌和屎肠球菌在美国感染人类的潜在风险。该建模方法估计了美国每年与医疗保健相关的肠球菌感染的数量，这些感染对抗菌治疗具有抗性，并且由于在家禽中使用杆菌肽而来自家禽来源。参数估计被开发为“最大风险”，以高估对人类的风险。虽然基于bcrABDR基因位点的存在，预测来自家禽的大约60%的粪肠球菌和粪肠球菌具有杆菌肽抗性，很少有人类分离株具有这种特征。此外，在2002年至2019年期间,在家禽来源中未检测到粪肠球菌或屎肠球菌的万古霉素或利奈唑胺耐药菌株.该模型估计每年由于禽类中使用杆菌肽而可能抵抗治疗的抗微生物药物粪肠球菌和屎肠球菌病例的数量分别为0.86和0.14。这意味着美国人口中粪肠球菌的年度风险估计不到3.5亿分之一，粪肠球菌的年度风险估计不到20亿分之一。即使使用风险最大化假设，结果表明,在美国家禽中按照标签说明使用杆菌肽对人类健康的风险可以忽略不计.
