Pak J Biol Sci. 2022 Jun;25(7):586-601. doi: 10.3923/pjbs.2022.586.601.
<b>Background and Objective:</b> The housefly poses a threat to the public health of humans and domestic animals since it can carry and transmit pathogens. Despite there are many attempts to control this insect, most of them depend on conventional pesticides. Thus, the current study aimed to evaluate the efficacy of whole-cell suspension, cell-free supernatant and crude cells of the symbiotic bacteria <i>Photorhabdus</i> sp. and <i>Xenorhabdus</i> sp., as bio-control agents for housefly stages. <b>Materials and Methods:</b> The <i>Photorhabdus</i> sp. and <i>Xenorhabdus</i> sp., were isolated from the entomopathogenic nematodes, <i>Heterorhabditis indica</i> and <i>Steinernema feltiae</i>, respectively. The phenotypic, as well as the enzymatic characterizations of both bacteria, were determined. In addition, histopathological changes of the alimentary canal of <i>M. domestica</i> adults treated with whole-cell suspensions (at 3×10<sup>8 </sup>cells mL<sup></sup><sup>1</sup>) of both bacteria were carefully examined using transmission electron microscopy. <b>Results:</b> The results showed that both symbiotic bacteria significantly suppressed larvae, pupae and adults of <i>M. domestica</i>, particularly when they were applied as whole-cell suspensions. For example, the highest concentration of whole-cell suspension, cell-free supernatant and crude cells of <i>Photorhabdus</i> sp., induced larval mortalities by 94.7, 64.0 and 45.3%, while those of <i>Xenorhabdus</i> sp., induced larval mortalities by 58.7, 46.7 and 30.7% at 96 hrs, respectively. The results also showed that whole-cell suspensions of both symbiotic bacteria caused severe histopathological changes in the ultrastructure of the treated adults' alimentary canal. <b>Conclusion:</b> Both symbiotic bacteria can be effectively used, particularly the whole-cell suspension, as bio-control agents against the housefly either in the larval or adult stage.
家蝇会携带并传播病原体，从而对人类和家养动物的公共卫生构成威胁。尽管人们已经尝试了许多方法来控制这种昆虫，但大多数方法都依赖于传统的杀虫剂。因此，本研究旨在评估共生细菌<i>Photot habdus</i>和<i>Xenorhabdus</i>的全细胞悬浮液、无细胞上清液和粗细胞作为家蝇各虫期生物防治剂的功效。材料与方法：从昆虫病原线虫<i>Heterorhabditis indica</i>和<i>Steinernema feltiae</i>中分离出了<i>Photot habdus</i>和<i>Xenorhabdus</i>。对这两种细菌进行了表型和酶特性的鉴定。此外，还使用透射电子显微镜仔细检查了用两种细菌的全细胞悬浮液（3×10<sup>8 </sup>个细胞 mL<sup></sup><sup>1</sup>）处理后家蝇<i>M.domestica</i>成虫的消化道的组织病理学变化。结果：结果表明，两种共生细菌都能显著抑制家蝇幼虫、蛹和成虫，尤其是当它们作为全细胞悬浮液使用时。例如，<i>Photot habdus</i>的全细胞悬浮液、无细胞上清液和粗细胞的最高浓度分别诱导幼虫死亡率达到 94.7%、64.0%和 45.3%，而<i>Xenorhabdus</i>的全细胞悬浮液、无细胞上清液和粗细胞的最高浓度分别诱导幼虫死亡率达到 58.7%、46.7%和 30.7%，在 96 小时时达到。结果还表明，两种共生细菌的全细胞悬浮液都会导致处理成虫消化道的超微结构发生严重的组织病理学变化。结论：两种共生细菌都可以有效地用作生物防治剂，特别是全细胞悬浮液，可以在家蝇幼虫或成虫阶段使用。
