To understand the distribution and prevalence characteristics, virulence gene carriage,drug resistance trends and multi-drug resistance situation of Bacillus cereus in Ningxia Region.
This study conducted biochemical and mass spectrometry re-identification, multiple fluorescence quantitative polymerase chain reaction for virulence genes and microbroth dilution method for drug sensitivity tests on 312 isolates of Bacillus cereus obtained from monitoring points from 2010 to 2025, and analyzed the results.
A total of 312 strains of Bacillus cereus were detected from 2010 to 2025, including 284 strains from food samples and 28 strains from food poisoning. Among them, 78 strains were isolated in the early period, 112 in the middle period, and 122 in the late period. There were regional differences among the 5 cities of Yinchuan, Shizuishan, Wuzhong, Guyuan and Zhongwei. Yinchuan had the highest rate, followed by Wuzhong City, and the lowest was Shizuishan City. The carriage rate of virulence genes in Bacillus cereus exceeded 97%. The dominant genotype was double positive for gene nheB and gene hblC accounted for 52.82%. The resistance rates to ampicillin (AMP), penicillin (PEN), cefoxitin(CFX) and oxacillin (OXA) all exceeded 90%. The strains were 100% sensitive to ciprofloxacin (CIP),chloramphenicol (CHL), gentamicin (GEN), vancomycin (VAN) and imipenem (IMP). The most common resistance pattern was AMP-PEN-OXA-CFX, accounting for 60.90%.
The number of Bacillus cereus detected in Ningxia has been steadily increasing. It showes diversity in terms of time, source and region. The carriage rate of virulence genes is high, and the drug resistance situationwas is severe. Continuous monitoring of food and patients should be carried out, and effective measures should be taken for control to better ensure food safety and public health.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |