Out of Asia: the independent rise and global spread of fluoroquinolone-resistant Shigella

Abstract

Shigella are ranked among the most prevalent aetiologies of diarrhoeal disease worldwide, disproportionately affecting young children in developing countries and high-risk communities in developed settings. Antimicrobial treatment, most commonly with fluoroquinolones, is currently recommended for Shigella infections to alleviate symptoms and control disease transmission. Resistance to fluoroquinolones has emerged in differing Shigella species (S. dysenteriae, flexneri and sonnei) since the turn of the 21st century, originating in endemic areas, and latterly spreading into non-endemic regions. Despite occurring independently, the emergence of fluoroquinolone resistance in these different Shigella species shares striking similarities regarding their epidemiology and resistance mechanisms. Here, we review and discuss the current epidemiology of fluoroquinolone-resistant Shigella species, particularly in the light of recent genomic insights.

Keywords: Asia; Shigella; epidemiology; fluoroquinolone resistance; genomic; quinolone resistance determining region (QRDR).

Fig. 1.

Worldwide distribution of FQR Shigella. Countries are coloured where different FQR Shigella species have been reported in the literature (see key). Black filled circles indicate specific regions where FQR Shigella have been isolated. Countries with no information or have not reported isolation of FQR Shigella are coloured grey. HCMC, Ho Chi Minh city.

Fig. 2.

Timeline detailing the emergences of FQR Shigella species. The dashed lines represent the first occurrences of the initial QRDR mutation in the FQR clone if known, as described by epidemiological or genomic data. The solid lines indicate the first reports of FQR Shigella species as well as the QRDR mutations that became incorporated into these clones by this designated time. The presumed order of occurrence for these mutations is from top to bottom.