To investigate the antimicrobial susceptibility and molecular characteristics of Bordetella pertussis (Bp)in Guizhou Province, in order to provide a scientific basis for pertussis prevention, control, and treatment strategy formulation.
Bp strains collected from Guizhou Province between 2017 and 2024 were isolated and identified, followed by antimicrobial susceptibility testing against 10 antibiotics, including erythromycin, azithromycin, and clarithromycin, using the E-test method. Based on next-generation sequencing, drug resistance gene locus detection and multilocus sequence typing(MLST)were performed. Pulsed field gel electrophoresis(PFGE)molecular typing was performed using the restriction enzyme XbaI.
Of the 36 collected Bp strains, the resistance rate to macrolide antibiotics was 83.3% (30/36), increasing from 40% (2/5)in 2017 to 100% (19/19)in 2024. All resistant isolates harbored the A2047G mutation in the 23S rRNA gene. The susceptibility rate to Sulfamethoxazole-Trimethoprim was 58.3% (21/36), while all strains (100%, 36/36)were susceptible to ceftriaxone, meropenem, ampicillin, ciprofloxacin, levofloxacin, and gentamicin. Multilocus sequence typing (MLST)identified all isolates as sequence type 2 (ST-2). Pulsed-field gel electrophoresis (PFGE)classified the strains into 21 pulsotypes and 5 clusters, with epidemic strains from 2023—2024 predominantly belonging to cluster C and exhibiting significant genetic divergence from earlier isolates.
Bp strains in Guizhou Province presents heterogeneous PFGE profiles, varying over time in genetic features and macrolide sensitivity, and differing molecularly from vaccine strains.
| 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 |