AUTHOR=Ko Karrie K. K. , Chu Joash Jun Keat , Lim Kar Mun , Yingtaweesittikul Hatairat , Huang Wenjie , Tan Shireen Yan Ling , Goh Kenneth Choon Meng , Tan Si Huei , Ng Tong Yong , Maiwald Matthias , Chia Jonathan Wei Zhong , Cao Delphine Yanhong , Tan Yen Ee , Sim James Heng Chiak , Koh Tse Hsien , Nagarajan Niranjan , Suphavilai Chayaporn 

TITLE=Clonal serotype 1c multidrug-resistant Shigella flexneri detected in multiple institutions by sentinel-site sequencing

JOURNAL=Frontiers in Medicine

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.964640

DOI=10.3389/fmed.2022.964640

ISSN=2296-858X

ABSTRACT=<p><italic>Shigella flexneri</italic> is a major diarrhoeal pathogen, and the emergence of multidrug-resistant <italic>S. flexneri</italic> is of public health concern. We report the detection of a clonal cluster of multidrug-resistant serotype 1c (7a) <italic>S. flexneri</italic> in Singapore in April 2022. Long-read whole-genome sequence analysis found five <italic>S. flexneri</italic> isolates to be clonal and harboring the extended-spectrum β-lactamases <italic>bla</italic><sub>CTX−M−15</sub> and <italic>bla</italic><sub>TEM−1</sub>. The isolates were phenotypically resistant to ceftriaxone and had intermediate susceptibility to ciprofloxacin. The <italic>S. flexneri</italic> clonal cluster was first detected in a tertiary hospital diagnostic laboratory (sentinel-site), to which the <italic>S. flexneri</italic> isolates were sent from other hospitals for routine serogrouping. Long-read whole-genome sequence analysis was performed in the sentinel-site near real-time in view of the unusually high number of <italic>S. flexneri</italic> isolates received within a short time frame. This study demonstrates that near real-time sentinel-site sequence-based surveillance of convenience samples can detect possible clonal outbreak clusters and may provide alerts useful for public health mitigations at the earliest possible opportunity.</p>