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Updated: May 8, 2025
Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Molecular characterization and antimicrobial susceptibility for 62 isolates of Bordetella pertussis from children
Baohua He1, Zhaoyi Jia1, Fei Zheng2
1Hebei Key Laboratory of Pathogens and Epidemiology of Infectious Diseases, HeBei Provincial Center for Disease Control and Prevention, Shijiazhuang, China.
Insights
Pertussis resurgence is linked to evolving Bordetella pertussis (BP) genotypes and antimicrobial resistance in China. This suggests a need to reevaluate pertussis immunization strategies and develop new vaccines to combat resistance.
Area of Science:
- Microbiology
- Genomics
- Epidemiology
Background:
- Pertussis, caused by Bordetella pertussis (BP), is a highly contagious respiratory illness.
- Despite widespread immunization, pertussis incidence is rising globally, including in China.
- Understanding circulating BP strains' genotypes and antibiotic resistance is crucial for control.
Purpose of the Study:
- To investigate the genotypes and antimicrobial susceptibility of Bordetella pertussis strains from children in Hebei, China.
- To analyze the genomic diversity and evolutionary traits of Chinese BP strains in a global context.
Main Methods:
- Antimicrobial susceptibility testing (AST) and whole-genome sequencing (WGS) were performed on 62 BP isolates.
- Multilocus sequence typing (MLST), multilocus antigen sequence typing (MAST), and multilevel genome typing (MGT) were employed.
- Genomic data were compared with 313 international BP genomes.
Main Results:
- Two dominant BP phylogenetic groups were identified, distinct from vaccine strains.
- Significant erythromycin (56/62) and azithromycin (55/62) resistance was observed.
- Erythromycin-resistant strains (Lineage I, MGT2 ST7) harbored the ptxP1 gene and 23S rRNA A2047G mutation.
Conclusions:
- Antimicrobial resistance in BP may be linked to specific molecular types and evolutionary changes.
- Selection pressures from antibiotics and immunization likely drive BP evolution in China.
- Reevaluation of immunization strategies and development of novel vaccines are necessary to address pertussis resurgence and resistance.
Background:
Pertussis is a highly contagious respiratory disease caused by Bordetella pertussis (BP). Despite global control of pertussis cases through the Expanded Programme on Immunization (EPI), there has been a significant increase in the incidence of pertussis in recent years, characterized by a "resurgence" in developed countries with high immunization rates as well as a comparable reemergence in certain areas of China. We aim to explore the genotypes and antimicrobial susceptibility of circulating BP from children in Hebei.
Study Design:
Children diagnosed with BP infection from 2019 to 2020 in Hebei, China were enrolled. We performed antimicrobial susceptibility testing (AST), whole-genome sequencing (WGS) analysis, single nucleotide polymorphism (SNP) detection, mltilocus sequence typing (MLST), multilocus antigen sequence typing (MAST), multilevel genome typing (MGT). A total of 313 international BP genomes were selected for comparison to examine the genomic diversity and evolutionary traits of Chinese strains within a global framework.
Results:
Sixty-two individuals were identified with BP infection via culture, yielding a positive rate of 15.62% (62/397) for BP. Two phylogenetic groups were identified, each carrying a dominating genotype. The two vaccine strains, CS and Tohama I, exhibited a distant relationship to these two groups. This study identified 56 erythromycin-resistant isolates, 55 azithromycin-resistant isolates, 58 sulfamethoxazole-sensitive isolates, and 53 cefotaxime-sensitive isolates. All BP isolates were sensitive to levofloxacin, amoxicillin, ceftriaxone, and meropenem. Meanwhile, all erythromycin-resistant strains, which belonged to lineage I and MGT2 sequence type 7 (ST7), shared the ptxP1 gene and contained the 23S rRNA A2047G mutation. The major MAST was prn1/ptxP1/ptxA1/fim3-1/fim2-1 (75.81%). All 62 BP strains were divided into 1, 2, 3, 14, and 52 types at the MGT1, MGT2, MGT3, MGT4, and MGT5 levels, respectively.
Conclusion:
This work showed that there may be a link between antimicrobial resistance and alterations in specific molecular types, and the isolates showed a clear change when compared with the vaccine strain and that selection pressure from both antibiotics and immunization may be responsible for driving Chinese BP evolution, and necessitate a reevaluation of the immunization strategy and the development of novel vaccines in China to halt the resurgence and medication resistance of pertussis.
