Community outbreak of invasive group A streptococcus infection in Ontario, Canada

Abstract

Background: Outbreaks of invasive group A streptococcal infection (iGAS) have historically occurred in institutional settings. Increasingly, community-based outbreaks have been reported, often among marginalized populations, yet few guidelines exist for managing iGAS outbreaks in such settings. Objective: To describe the ongoing outbreak of iGAS in Middlesex-London, Ontario, and the challenges that arose while applying current guidelines to a marginalized population in a community setting. Methods: The outbreak investigation included all iGAS cases in Middlesex-London with an onset date from April 1, 2016 to February 28, 2018. Clinical specimens were submitted to provincial and federal laboratories for typing. Public health management of the outbreak involved environmental health inspections, contact tracing, chemoprophylaxis of close contacts, swabbing to determine colonization rates of Streptococcus pyogenes, and communicating with stakeholders and the public. Results: A total of 156 confirmed cases of iGAS corresponding to 147 individuals were reported in less than two years. More than 60% of cases occurred in men (n=91) and almost half (n=71) of the total number of cases were persons who used drugs (PWUD) and/or were under-housed. Of the PWUD cases, 58 of 65 (89%) used injection drugs. Key challenges in controlling this outbreak included reaching PWUD and under-housed people; completing a case history and contact list; facilitating completion of treatment; dealing with concurrent infections such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV); and optimizing environmental health conditions. Guidelines were adapted so contacts who shared drugs or injection drug equipment with a known iGAS case would be offered chemoprophylaxis regardless of the clinical severity of the case. To optimize treatment completion, a single-dose of azithromycin for individuals in close contact with PWUD and/or under-housed cases was given. Cases with macrolide-resistant strain emm9 have recently emerged. Conclusion: The application of institution-based guidelines for iGAS outbreaks has been ineffective in controlling this particular community outbreak. There is a need for guidelines on managing outbreaks of iGAS in the community especially when an outbreak involves marginalized populations.

A controlled-release oral opioid supports S. aureus survival in injection drug preparation equipment and may increase bacteremia and endocarditis risk

“…pyogenes requires 12 additional amino acids to be added to the minimal growth media to support its growth [35–37]. Nevertheless S. pyogenes is an important pathogen in PWID with multiple outbreaks of disease associated with this organism, including in London, Ontario [38]. We suspect that crowding within homeless shelters, frequent soft tissue injury, as well as pre-injection practices (such as licking of the needle) may lead to these infections rather than contamination of the injectate.…”

All together now: aggregating multiple records to develop a person-based dataset to integrate and enhance infectious disease surveillance in Ontario, Canada

“…Second, despite the overlap in modes of acquisition/transmission between HIV/AIDS and hepatitis C and iGAS, specifically sharing of drug use equipment, there were only 59 clients in our dataset with all three disease types. Data from the aforementioned London, Ontario, iGAS outbreak investigation indicated that 9.5% of individuals (14/147) with iGAS infections were positive for both HCV and HIV (Dickson et al 2018 ). These individuals would represent 23.7% (14/59) of the clients with HCV, HIV/AIDS, and iGAS records in our dataset.…”

“…Almost half of the iGAS cases in the outbreak were among marginalized populations, specifically in people who use drugs, people who are underhoused, or both. Many of the cases had hepatitis C (HCV) co-infections and a number of them had HCV-HIV co-infections (Dickson et al 2018 ).…”

“…The second was to conduct descriptive analyses of this initial dataset to assess the frequency of multiple disease events in individuals. This was done using a subset of diseases that have common modes of acquisition and transmission or among diseases with known co-morbidity, namely chlamydia, gonorrhea, infectious syphilis, acute and chronic hepatitis B (HBV), HCV, HIV/AIDS, tuberculosis (TB), and iGAS (Dickson et al 2018 ; Public Health Agency of Canada 2014 ; Public Health Agency of Canada 2019 ).…”

Immunization With a Secreted Esterase Protects Mice Against Multiple Serotypes (M1, M3, and M28) of Group A Streptococcus

“…Streptococcus pyogenes also called Group A Streptococcus (GAS), can produce an arsenal of extracellular secreted proteins to evade the innate immune system (Walker et al, 2014;Hynes and Sloan, 2016;Liu and Lei, 2018;Happonen et al, 2019). Although treated with modern medicine, it remains a significant cause of global morbidity and mortality (Dickson et al, 2018;Hua et al, 2019;Lynskey et al, 2019). Historically, many of these secreted proteins have been studied to find the mechanisms by which they facilitate the resistance against host defenses as well as to find possible candidate antigens for vaccines.…”