Entomology and Nematology Department, University of Florida, Gainesville, FL.
Emerging Pathogens Institute, University of Florida, Gainesville, FL.
J Med Entomol. 2021 Mar 12;58(2):921-928. doi: 10.1093/jme/tjaa241.
Antibiotic use in livestock accounts for 80% of total antibiotic use in the United States and has been described as the driver for resistance evolution and spread. As clinical infections with multidrug-resistant pathogens are rapidly rising, there remains a missing link between agricultural antibiotic use and its impact on human health. In this study, two species of filth flies from a livestock operation were collected over the course of 11 mo: house flies Musca domestica (L.) (Diptera: Muscidae), representing a generalist feeder, and stable flies Stomoxys calcitrans (L.) (Diptera: Muscidae), representing a specialist (blood) feeder. The prevalence of flies carrying cefotaxime-resistant (CTX-R) bacteria in whole bodies and dissected guts were assayed by culturing on antibiotic-selective media, with distinct colonies identified by Sanger sequencing. Of the 149 flies processed, including 81 house flies and 68 stable flies, 18 isolates of 12 unique bacterial species resistant to high-level cefotaxime were recovered. These isolates also showed resistance to multiple classes of antibiotics. The CTX-R isolates were predominantly recovered from female flies, which bore at least two resistant bacterial species. The majority of resistant bacteria were isolated from the guts encompassing both enteric pathogens and commensals, sharing no overlap between the two fly species. Together, we conclude that house flies and stable flies in the field could harbor multidrug-resistant bacteria. The fly gut may serve as a reservoir for the acquisition and dissemination of resistance genes.
抗生素在畜牧业中的使用占美国抗生素总用量的 80%，并被描述为耐药进化和传播的驱动因素。随着临床多重耐药病原体感染的迅速增加，农业抗生素使用及其对人类健康的影响之间仍然存在缺失环节。在这项研究中，从一个畜牧业操作中收集了两种污垢苍蝇，历时 11 个月：家蝇 Musca domestica（双翅目：蝇科），代表一种普通饲料，和厩螫蝇 Stomoxys calcitrans（双翅目：蝇科），代表一种专门（血液）饲料。通过在抗生素选择性培养基上培养来检测整只苍蝇和解剖肠道中携带头孢噻肟耐药（CTX-R）细菌的苍蝇的流行率，并用 Sanger 测序对具有明显菌落的细菌进行鉴定。在处理的 149 只苍蝇中，包括 81 只家蝇和 68 只厩螫蝇，从 12 个独特的细菌种中分离出了 18 个对头孢噻肟高水平耐药的分离株。这些分离株也表现出对多种类抗生素的耐药性。CTX-R 分离株主要从雌性苍蝇中回收，这些苍蝇至少携带两种耐药细菌。大多数耐药细菌是从肠道中分离出来的，肠道中既有肠道病原体也有共生菌，两种苍蝇之间没有重叠。总的来说，我们得出结论，田间的家蝇和厩螫蝇可能携带多种耐药细菌。蝇的肠道可能是获得和传播耐药基因的储库。
