Mramba F, Broce A B, Zurek L
Department of Entomology, Kansas State University, Manhattan, KS 66506, USA.
J Vector Ecol. 2007 Jun;32(1):134-9. doi: 10.3376/1081-1710(2007)32[134:vcosfs]2.0.co;2.
Enterobacter sakazakii is an opportunistic food-borne pathogen causing meningitis, enterocolitis, and sepsis, primarily in immunocompromised infants. It has been suggested that stable flies, Stomoxys calcitrans L., are a vector/reservoir of this pathogen. In this study, we assessed a) vector competence of adult stable flies (SF) for E. sakazakii, b) effect of E. sakazakii on SF development, and c) survival of E. sakazakii during SF development and colonization of the digestive tract of newly-emerged flies. Our data show that in the colony, adult SF can maintain E. sakazakii for at least 20 days regardless of the food source (blood or sugar) and contaminate the food source. The concentration of the pathogen per individual SF ranged from 1.8 x 10(5) to 6.4 x 10(6) CFU. E. sakazakii supported development of immature SF in sterilized cattle manure and sterilized artificial medium (78.3% and 76.7% SF survival to adult stage, respectively). In addition, E. sakazakii survived during SF development and colonized the gut of emerging adult SF but only when SF larvae were maintained on sterilized cattle manure inoculated with E. sakazakii (12.8% prevalence in adult SF) and on the sterile artificial medium with E. sakazakii (21.7% prevalence in adult SF). E. sakazakii was not recovered from flies or the substrate when larvae were reared on cattle manure with a non-sterilized complex microbial community plus the E. sakazakii inoculum. This study shows that SF adults have a potential to carry E. sakazakii for an extended period of time. E. sakazakii supports SF development and can survive during SF pupation and then colonize the gut of newly-emerged flies.
阪崎肠杆菌是一种机会性食源性病原体，主要在免疫功能低下的婴儿中引起脑膜炎、小肠结肠炎和败血症。有人提出厩螫蝇（Stomoxys calcitrans L.）是这种病原体的载体/宿主。在本研究中，我们评估了：a）成年厩螫蝇对阪崎肠杆菌的媒介能力；b）阪崎肠杆菌对厩螫蝇发育的影响；c）阪崎肠杆菌在厩螫蝇发育和新羽化蝇消化道定殖过程中的存活情况。我们的数据表明，在饲养群体中，成年厩螫蝇无论以何种食物来源（血液或糖分）都能使阪崎肠杆菌存活至少20天，并污染食物来源。每只成年厩螫蝇携带的病原体浓度范围为1.8×10⁵至6.4×10⁶CFU。阪崎肠杆菌在灭菌牛粪和灭菌人工培养基中支持未成熟厩螫蝇的发育（分别有78.3%和76.7%的厩螫蝇存活至成虫阶段）。此外，阪崎肠杆菌在厩螫蝇发育过程中存活下来，并定殖于新羽化的成年厩螫蝇肠道，但前提是厩螫蝇幼虫饲养在接种了阪崎肠杆菌的灭菌牛粪上（成年厩螫蝇中的感染率为12.8%）以及含有阪崎肠杆菌的无菌人工培养基上（成年厩螫蝇中的感染率为21.7%）。当幼虫在含有未灭菌复杂微生物群落加阪崎肠杆菌接种物的牛粪上饲养时，未从蝇或基质中分离到阪崎肠杆菌。本研究表明成年厩螫蝇有潜力长时间携带阪崎肠杆菌。阪崎肠杆菌支持厩螫蝇发育，并且能在厩螫蝇化蛹期间存活，然后定殖于新羽化蝇的肠道。
