Shiga Toxin 1-Producing Shigella sonnei Infections, California, United States, 2014-2015

• Published in: Emerging infectious diseases 2016-04, Vol.22 (4), p.679-686
• Main Authors: Lamba, Katherine, Nelson, Jennifer A, Kimura, Akiko C, Poe, Alyssa, Collins, Joan, Kao, Annie S, Cruz, Laura, Inami, Gregory, Vaishampayan, Julie, Garza, Alvaro, Chaturvedi, Vishnu, Vugia, Duc J
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anti-Bacterial Agents - therapeutic use; California - epidemiology; Child; Child, Preschool; Diarrhea - epidemiology; Diarrhea - microbiology; Diarrhea - pathology; dysenteriae; Dysentery, Bacillary - epidemiology; Dysentery, Bacillary - microbiology; Dysentery, Bacillary - pathology; Electrophoresis, Gel, Pulsed-Field; Epidemiological Monitoring; flexneri; Humans; Infant; Infant, Newborn; Infections, California, United States, 2014–2015; Initially identified among persons with travel links to Mexico, this pathogen spread by domestic transmission to 42 of 56 case-patients; Middle Aged; Shiga Toxin 1 - biosynthesis; Shiga Toxin 1 - isolation & purification; Shiga Toxin 1–Producing; Shigella; Shigella sonnei - classification; Shigella sonnei - genetics; Shigella sonnei - isolation & purification; Shigella, sonnei, dysenteriae, flexneri, Escherichia coli, Shiga toxin; shigellemia, STEC, Stx-1 shigellosis, bacteria, diarrhea, cytotoxins, enteric infections, gastrointestinal, travel, antimicrobial drugs, antibiotic re; sonnei
• ISSN: 1080-6040; 1080-6059
• DOI: 10.3201/eid2204.151825

Shiga toxins (Stx) are primarily associated with Shiga toxin-producing Escherichia coli and Shigella dysenteriae serotype 1. Stx production by other shigellae is uncommon, but in 2014, Stx1-producing S. sonnei infections were detected in California. Surveillance was enhanced to test S. sonnei isolates for the presence and expression of stx genes, perform DNA subtyping, describe clinical and epidemiologic characteristics of case-patients, and investigate for sources of infection. During June 2014-April 2015, we identified 56 cases of Stx1-producing S. sonnei, in 2 clusters. All isolates encoded stx1 and produced active Stx1. Multiple pulsed-field gel electrophoresis patterns were identified. Bloody diarrhea was reported by 71% of case-patients; none had hemolytic uremic syndrome. Some initial cases were epidemiologically linked to travel to Mexico, but subsequent infections were transmitted domestically. Continued surveillance of Stx1-producing S. sonnei in California is necessary to characterize its features and plan for reduction of its spread in the United States.