【目的】 探索美洲大蠊Periplaneta americana的细菌群落结构，以揭示其如何获得和携带致病菌。同时，了解这些菌群对宿主的潜在益处，为解析微生物如何促进美洲大蠊的生长发育提供数据支持，并为人工养殖提供指导，降低疾病传播风险。【方法】 采用16S rRNA扩增子的高通量测序技术，对野外种群和饲养种群美洲大蠊体表和体内细菌群落多样性进行分析，并使用PICRUSt2基于16S丰度数据预测群落功能。【结果】 美洲大蠊体表样本的菌群丰度低于体内样本，野生种群的体表样本在α和β多样性上显著高于饲养种群（P<0.05），但在体内样本中野生种群与饲养种群差异不明显（P>0.05）。在门分类水平上，美洲大蠊体表与体内样本的菌群主要集中在拟杆菌门Bacteroidetes（平均丰度：体表22.91%，体内64.07%）、变形菌门Proteobacteria（体表48.49%，体内12.83%）和厚壁菌门Firmicutes（体表20.26%，体内15.79%）上。线性判别分析（Linear discriminant analysis effect size，LEfSe）显示，野生种群的体表样本具有大量致病细菌，如沙雷氏菌属Serratia、不动杆菌属Acinetobacter和肠球菌属Enterococcus等。PICRUSt2功能预测发现，美洲大蠊体内菌群中与环境适应、氨基酸代谢、能量代谢、糖类生物合成和代谢、核苷酸代谢、以及复制与修复等功能相关的组分比例显著高于体表样本（P<0.05）。【结论】 美洲大蠊体内细菌群落组成相对稳定，但其丰度会受环境影响，这些菌群在代谢营养物质、适应环境和提高免疫力方面具有重要作用；美洲大蠊的致病菌主要从环境中获取，并附着于体表进行传播。因此，在养殖过程中应提供多样化的饮食以维护肠道菌群结构，并保持良好的卫生条件，减少致病菌的滋生和传播的风险。

[Aim]  To explore the bacterial community structure of the Periplaneta americana and investigate how it acquires and carries pathogenic bacteria. Additionally, to determine the potential benefits of these bacterial communities to the host, to gain a greater understanding of how microorganisms promote the growth and development of P. americana. The findings of this study may offer valuable guidance for the artificial breeding of P. americana, and insight into reducing the risk of disease transmission. [Methods]  High throughput 16S rRNA amplicon sequencing was used to analyze the bacterial community diversity in surface and internal samples of wild and artificially reared P. americana. Additionally, PICRUSt2 was used to predict community functions based on the composition and abundance of 16S rRNA. [Results]  The abundance of the bacterial communities in the surface samples were lower compared to the internal samples. Moreover, the surface samples from the wild populations had significantly higher α and β diversity compared to the artificially reared populations (P<0.05). However, there was no significant difference in the internal samples between the wild and artificially reared populations (P>0.05). At the phylum level, both the surface and internal samples of P. americana were primarily dominated by Bacteroidetes (average abundance: 22.91% on the surface and 64.07% internally), Proteobacteria (48.49% on the surface and 12.83% internally), and Firmicutes (20.26% on the surface and 15.79% internally). Significant differential features between different treatments were identified through linear discriminant analysis effect size (LEfSe). Notably, in both the wild population and cutaneous samples, we observed a significant presence of pathogenic bacteria from the genus Serratia, Acinetobacter, and Enterococcus. Functional predictions using PICRUSt2 revealed that the bacterial community in the internal samples of P. americana has a higher proportion of functional categories related to environmental adaptation, amino acid metabolism, energy metabolism, carbohydrate biosynthesis and metabolism, nucleotide metabolism, replication, and repair. Additionally, the proportions of these functional categories associated with the microbial community were significantly higher in the internal samples compared to the surface samples (P<0.05). [Conclusion]  The internal bacterial community of P. americana is relatively conservative and resistant to change, and plays a crucial role in nutrient metabolism, environmental adaptation, and immune enhancement. The pathogenic bacteria in P. americana are primarily acquired from the environment and mainly adhere to the surface for transmission. Therefore, a diversified diet should be offered to artificially farmed P. americana to prevent disrupting its gut microbiota structure, which could impact its normal growth and development. Additionally, it is crucial to maintain hygienic conditions in P. americana breeding facilities to reduce the risks of proliferation and transmission of pathogenic bacteria.