In Los Angeles, California, USA, persistent, refractory shigellosis was diagnosed in an immunocompetent man who has sex with men. Whole-genome sequencing augmented phenotypic antimicrobial susceptibility testing to comprehensively profile bacterial drug resistance and appropriately guide therapy and clear the infection.
Shigellosis is an infectious diarrheal illness traditionally associated with contaminated food and water.[1] Recent reports, however, have indicated increased transmission through sexual activity, including direct (anal/oral sex) and indirect (use of contaminated objects such as sex toys) sexual contact.[2] Several outbreaks of extensively drug-resistant (XDR) Shigella spp. among men who have sex with men (MSM) have been described.[3–5]
Recently, the emergence of sexually transmitted XDR Shigella flexneri serotype 2a was reported among gay, bisexual, and other MSM in England.[4] The study by the UK Health Security Agency characterized S. flexneri isolates harboring bla CTX-M-27 and identified the 2 phylogenetically related clusters, each composed of isolates within 10 single-nucleotide polymorphisms (SNPs). Long-read sequencing elucidated the genomic location of the resistance determinant, and plasmid similarities with XDR Shigella sonneifrom a current outbreak supported interspecies horizontal acquisition of drug resistance. Those findings underscore the substantial threat of mobilizable genetic elements and their role in propagating antimicrobial resistance (AMR). We describe a case of extensively drug-resistant
