Dataset Information

Prevalence of Plasmid-Mediated Determinants With Decreased Susceptibility to Azithromycin Among Shigella Isolates in Anhui, China.

ABSTRACT:

Objective

The aims of this study were to describe azithromycin (AZM) susceptibility patterns among Shigella isolates in Anhui, China and identify predictors of resistance with mobile element-mediated genes.

Methods

A total of 517 non-duplicate Shigella isolates (449 S. flexneri and 68 S. sonnei) were collected in the Anhui Province of China from September 2011-September 2015, and screened for the plasmid-mediated genes of decreased susceptibility to AZM (DSA), using polymerase chain reaction amplification and sequencing. Conjugation experiments and pulsed-field gel electrophoresis were conducted for all mphA-positive DSA isolates.

Results

The DSA rate for 449 S. flexneri isolates was 33.6%, compared with 39.7% for 68 S. sonnei isolates. Among 161 DSA S. flexneri isolates, 93 (57.8%) carried the mphA gene. Among 27 DSA S. sonnei isolates, 11 (40.7%) carried the mphA gene. However, other plasmid-mediated DSA genes were not found in these isolates. A total of 89 transconjugants (95.7%) were obtained from 93 mphA-positive S. flexneri isolates through conjugation, and 10 transconjugants (90.9%) were obtained from 11 mphA-positive S. sonnei isolates. Furthermore, the minimum inhibitory concentrations (MICs) of AZM among 89 S. flexneri transconjugants ranged from 4 to 128 μg/mL, with an MIC₅₀ of 8 μg/mL and MIC₉₀ of 32 μg/mL. The MICs of AZM among 10 S. sonnei transconjugants ranged from 4 to 256 μg/mL, with an MIC₅₀ of 8 μg/mL and MIC₉₀ of 64 μg/mL. Thirteen clusters were found for mphA-positive S. flexneri, and five clusters were found for mphA-positive S. sonnei. Furthermore, 10 homologous isolates among 13 mphA-positive S. flexneri isolates with high-level DSA were from Sixian county and were multidrug-resistant strains. Of the 10 homologous S. flexneri isolates, eight were from children (≤5 years old), and two from the elderly (>60 years old).

Conclusion

Our study demonstrates that the DSA for Shigella isolates was severe, and the plasmid-mediated mphA gene was the most common macrolide resistance gene detected in Shigella isolates collected in Anhui, China. The mphA-positive S. flexneri isolates with high-level DSA facilitated clonal spread in children and the elderly. This finding is noteworthy and warrants further study.

SUBMITTER: Liu Y

PROVIDER: S-EPMC7338677 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Publications

Prevalence of Plasmid-Mediated Determinants With Decreased Susceptibility to Azithromycin Among <i>Shigella</i> Isolates in Anhui, China.

Liu Yanyan Y Li Hongru H Lv Na N Zhang Yalong Y Xu Xihai X Ye Ying Y Gao Yufeng Y Li Jiabin J

Frontiers in microbiology 20200630

<h4>Objective</h4>The aims of this study were to describe azithromycin (AZM) susceptibility patterns among <i>Shigella</i> isolates in Anhui, China and identify predictors of resistance with mobile element-mediated genes.<h4>Methods</h4>A total of 517 non-duplicate <i>Shigella</i> isolates (449 <i>S. flexneri</i> and 68 <i>S. sonnei</i>) were collected in the Anhui Province of China from September 2011-September 2015, and screened for the plasmid-mediated genes of decreased susceptibility to AZM ...[more]

PMID: 32695071

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