Objective To establish a visual loop-mediated isothermal amplification detection method for rapid detection of Staphylococcus epidermidis. Methods A loop-mediated isothermal amplification system was established by selecting specific primers for SesB gene of Staphylococcus epidermidis. The visualization method of the reaction, the concentration of MgSO ₄, betaine in the system and the reaction temperature, time were optimized. The sensitivity and specificity of the optimized LAMP reaction and PCR reaction were compared. Results The optimal MgSO ₄ concentration in the loop-mediated isothermal amplification reaction system was 4mM. The optimal betaine concentration was 0.4M. The optimal reaction temperature and time were 63℃ for 60 min. The most suitable visualization method was calcein chromogenic method, and the visualization results were basically consistent with the results of agarose gel electrophoresis. Both LAMP and PCR reactions had good specificity. The sensitivity of LAMP reaction was 10 copies/μL, and the sensitivity of PCR reaction was 100 copies/μL. Conclusion LAMP assay is superior to PCR in the detection of Staphylococcus epidermidis infection. It is more suitable for grass-roots and remote areas due to its simple operation and short reaction time.

Objective To investigate the prevalence and species of tick-borne Rickettsiales in rural areas of Chengde City, and to provide a theoretical basis for the prevention and control of diseases caused by tick-borne Rickettsiales. Methods Total DNA was extracted from ticks collected from Sangou Town and Liugou Town of Chengde City, and the 16S rRNA gene was amplified by nested PCR to identify Rickettsiae bacteria. The heat shock protein(groEL) gene of Anaplasma and outer membrane protein A (ompA) gene of Rickettsia were amplified and sequenced for homology and phylogenetic analysis to identify the pathogens of tick-borne zoonotic Anaplasma and Rickettsia. Results A total of 336 ticks were collected from Sangou Town and Liugou Town, and all of them were identified as Haemaphysalis longicornis. The positive rate of Anaplasma was 25.3% (85/336) in ticks and 17.3% (58/336) in Rickettsia. The positive rate of Anaplasma in ticks was significantly higher than that in Rickettsia (P=0.01). The positive rates of Anaplasma capra and Anaplasma ovis were 8.3% (28/336) and 17.0% (57/336), respectively. The positive rate of Rickettsia sibirica and Rickettsia raoultii was 3.6% (12/58) and 6.3% (21/58), respectively. The positive rate of Candidatus Rickettsia jingxinensis was 7.4% (25/58). Conclusion Two zoonotic Anaplasma and three Rickettsia species were identified in H. longicornis in Chengde, indicating that Rickettsiae bacteria prevalent in rural areas around Chengde present high genetic diversity. And it is necessary to strengthen the monitoring and prevention and control of ticks and tick-borne pathogens in Chengde.