Adult house flies frequent microbe-rich sites such as urban dumpsters and animal facilities, and encounter and ingest bacteria during feeding and reproductive activities. Due to unique nutritional and reproductive needs, male and female flies demonstrate different interactions with microbe-rich substrates and therefore dissemination potential. We investigated culturable aerobic bacteria and coliform abundance in male and female flies (n = 107) collected from urban (restaurant dumpsters) and agricultural (dairy farm) sites. Whole-fly homogenate was aerobically cultured and enumerated on nonselective (tryptic soy agar; culturable bacteria) and selective (violet-red bile agar, VRBA; coliforms) media. Unique morphotypes from VRBA cultures of agricultural flies were identified and tested for susceptibility to 14 antimicrobials. Female flies harbored more bacteria than males and there was a sex by site interaction with sex effects on bacterial abundance at the urban site. Coliform abundance did not differ by sex, site or sex within site. Both male and female flies carried antimicrobial-resistant (AMR) bacteria: 36/38 isolates (95%) were resistant to 1 antimicrobial, 33/38 were multidrug-resistant (2), and 24/38 isolates were resistant to 4 antimicrobials. Our results emphasize the role of house flies in harboring bacteria including AMR strains that pose a risk to human and animal health.

中文翻译：

---

环境和性别对成年家蝇对细菌携带的影响（Musca domestica L.）。

成年房屋飞行频繁的富含微生物的场所，例如城市垃圾箱和动物设施，并且在进食和生殖活动中会遇到并吸收细菌。由于独特的营养和生殖需求，雄蝇和雌蝇表现出与富含微生物的底物的不同相互作用，因此具有传播潜力。我们调查了从城市（餐馆垃圾场）和农业（奶牛场）场所收集的雄性和雌性果蝇（n = 107）中可培养的需氧细菌和大肠菌群的丰度。将全蝇匀浆进行需氧培养，并在非选择性（胰蛋白酶大豆琼脂；可培养细菌）和选择性（紫红色胆琼脂，VRBA；大肠菌）培养基上进行计数。鉴定了来自农蝇VRBA培养物的独特形态型，并测试了其对14种抗菌药的敏感性。雌蝇中的细菌比雄蝇中的细菌多，并且在城市中存在着按性别的相互作用以及对细菌丰度的性别影响。大肠菌群的丰度没有性别，部位或部位内性别的差异。雄蝇和雌蝇都带有抗药性（AMR）细菌：36/38分离株（95％）对1种抗药性有抵抗力，33/38对多种药物有抗药性（2），24/38分离株对4种抗药性有抗性。我们的结果强调了家蝇在掩盖细菌（包括对人类和动物健康构成风险的AMR菌株）中的作用。36/38分离株（95％）对1种抗菌素有抵抗力，33/38对多种药物有耐药性（2），而24/38分离株对4种抗菌素有抵抗力。我们的结果强调了家蝇在掩盖细菌（包括对人类和动物健康构成风险的AMR菌株）中的作用。36/38分离株（95％）对1种抗菌素有抵抗力，33/38对多种药物有耐药性（2），而24/38分离株对4种抗菌素有抵抗力。我们的结果强调了家蝇在掩盖细菌（包括对人类和动物健康构成风险的AMR菌株）中的作用。