Carey, Megan E; Jain, Ruby; Yousuf, Mohammad; Maes, Mailis; Dyson, Zoe A; Thu, Trang Nguyen Hoang; Nguyen Thi Nguyen, To; Ho Ngoc Dan, Thanh; Nhu Pham Nguyen, Quynh; Mahindroo, Jaspreet; +4 more... Thanh Pham, Duy; Sandha, Kawaljeet Singh; Baker, Stephen; Taneja, Neelam; (2021) Spontaneous Emergence of Azithromycin Resistance in Independent Lineages of Salmonella Typhi in Northern India. Clinical Infectious Diseases, 72 (5). e120-e127. ISSN 1058-4838 DOI: https://doi.org/10.1093/cid/ciaa1773
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Abstract
BACKGROUND: The emergence and spread of antimicrobial resistance (AMR) pose a major threat to the effective treatment and control of typhoid fever. The ongoing outbreak of extensively drug-resistant Salmonella Typhi (S. Typhi) in Pakistan has left azithromycin as the only remaining broadly efficacious oral antimicrobial for typhoid in South Asia. Ominously, azithromycin-resistant S. Typhi organisms have been subsequently reported in Bangladesh, Pakistan, and Nepal. METHODS: Here, we aimed to understand the molecular basis of AMR in 66 S. Typhi organisms isolated in a cross-sectional study performed in a suburb of Chandigarh in Northern India using whole-genome sequencing and phylogenetic analysis. RESULTS: We identified 7 S. Typhi organisms with the R717Q mutation in the acrB gene that was recently found to confer resistance to azithromycin in Bangladesh. Six out of the seven azithromycin-resistant S. Typhi isolates also exhibited triple mutations in gyrA (S83F and D87N) and parC (S80I) genes and were resistant to ciprofloxacin. These contemporary ciprofloxacin/azithromycin-resistant isolates were phylogenetically distinct from each other and from those reported from Bangladesh, Pakistan, and Nepal. CONCLUSIONS: The independent emergence of azithromycin-resistant typhoid in Northern India reflects an emerging broader problem across South Asia and illustrates the urgent need for the introduction of typhoid conjugate vaccines in the region.
Item Type | Article |
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Faculty and Department | Faculty of Infectious and Tropical Diseases > Department of Infection Biology |
PubMed ID | 33515460 |
Elements ID | 159058 |
Official URL | http://dx.doi.org/10.1093/cid/ciaa1773 |
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Filename: Carey_etal_2021_Spontaneous-emergence-of-azithromycin-resistance.pdf
Licence: Creative Commons: Attribution 4.0
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