Shigella flexneri serotype 1 infections in men who have sex with men in Vancouver, Canada

Abstract

ObjectivesOutbreaks of shigellosis have been documented in men who have sex with men (MSM), associated with interpersonal transmission and underlying HIV infection. We observed a rise in Shigella flexneri isolates identified in a downtown tertiary-care hospital laboratory located within the city centre community health area (CHA-1) of Vancouver, Canada. The objectives of this study were to evaluate clinical outcomes of shigellosis cases among MSM admitted to hospital and to evaluate trends in Shigella cases within Vancouver, Canada. MethodsAdult rates of shigellosis were analysed by gender and health region, from 2005 to 2011, followed by retrospective chart review of all hospital laboratory-identified S. flexneri cases from 2008 to 2012. Serotyping and pulsed-field gel electrophoresis (PFGE) were performed on these isolates. ResultsAlthough shigellosis rates in men within CHA-1 did not change from 2005 to 2011 (range 33.4-68.5 per 100 000; P = 0.74), they were significantly higher than in other regions within the city of Vancouver (P ≤ 0.001) and the province of British Columbia (P ≤ 0.001). Shigella flexneri rates in men within CHA-1 increased significantly (range 2.3-51.4 per 100 000; P < 0.001), starting in 2008, and were higher than in other regions within Vancouver (P ≤ 0.01). Seventy-nine isolates of S. flexneri from 72 patients were identified by a single hospital laboratory. All patients were male and predominantly MSM (91.7%) and HIV-infected (86.1%), with most (92.6%) demonstrating CD4 counts ≥ 200 cells/μL. In total, 38.0% required hospitalization. Most (87.3%) had S. flexneri serotype 1 infection, with 72.9% of these representing a single PFGE pattern. ConclusionsWe identified high levels of transmission of a primarily clonal strain of S. flexneri serotype 1 in our local MSM population, resulting in a substantial burden of illness and health care resource use secondary to hospital admissions. [3][4][5]. From 1970 to 1985, a significant demographic shift occurred in the USA with respect to S. flexneri infection, with a more than fivefold increase in the infection rate in men 30 to 39 years old, despite no change in women of comparable age [6]. MSM transmission was felt to be a likely explanation for this change, with acquisition thought to be related to sexual practices of oral−anal and oral−genital contact [6]. In 1996, HIV was also identified as an important risk factor for shigellosis, after higher rates of Shigella infection were noted in a population that was significantly more likely to be adult, male and HIV-infected [7]. A case−control study was performed in the San Francisco area during a nonoutbreak period from 1998 to 1999, with multivariate analysis demonstrating a significant association of shigellosis with MSM, HIV infection, direct oral−anal contact and foreign travel [8]. Shigella flexneri appeared to be the predominant species in MSM during that period and, compared with S. sonnei, was significantly associated with MSM, HIV infection, direct anal contact, and lack of foreign travel ...

Intensified shigellosis epidemic associated with sexual transmission in men who have sex with men - Shigella flexneri and S. sonnei in England, 2004 to end of February 2015

“…There are four species of Gram-negative bacteria of the genus Shigella that cause severe bacillary dysentery in humans (S. flexneri, S. sonnei, S. boydii, and S. dysenteriae) with over 50 serotypes described. Although many cases in England are associated with travel to high-incidence regions such as the Indian subcontinent, North and East Africa and South America, outbreaks of S. flexneri and S. sonnei associated with sexual transmission between men who have sex with men (MSM) have been reported in the United Kingdom (UK), Germany, Spain, Australia, Canada and the United States [1][2][3][4][5][6][7][8][9].…”

Les infections entériques sont-elles transmises sexuellement en Colombie-Britannique?

“…La shigellose, l'amibiase et la giardiase sont des maladies transmissibles à déclaration obligatoire en Colombie-Britannique. Même si d'anciens rapports ont souligné des éclosions de shigellose parmi la population des HARSAH en Colombie-Britannique (20)(21)(22), l'épidémiologie des infections entériques transmissibles sexuellement, notamment la shigellose, n'a jamais été évaluée en Colombie-Britannique et n'est donc pas bien comprise. L'objectif de cette étude consistait à décrire l'épidémiologie de ces trois infections en Colombie-Britannique afin de déterminer si une transmission sexuelle peut se produire et de définir la population et les régions présentant un risque d'infection entérale transmissible sexuellement.…”

“…La première éclosion a eu lieu au début de 2007 et a touché les HARSAH, et la deuxième éclosion provoquée par une souche différente de Shigella sonnei a eu lieu à la fin de 2007 et a touché les sans-abri(22). Une troisième éclosion de Shigella sonnei associée à un restaurant local a eu lieu en 2010 dans la région de prestation de services de santé de l'Okanagan(20). La dernière éclosion, provoquée par la Shigella flexneri, a eu lieu entre 2008 et 2012 et a touché les HARSAH dans la région de prestation de services de santé de Vancouver(20).…”

“…Une troisième éclosion de Shigella sonnei associée à un restaurant local a eu lieu en 2010 dans la région de prestation de services de santé de l'Okanagan(20). La dernière éclosion, provoquée par la Shigella flexneri, a eu lieu entre 2008 et 2012 et a touché les HARSAH dans la région de prestation de services de santé de Vancouver(20).…”

Are enteric infections sexually transmitted in British Columbia?

“…Shigellosis, amebiasis and giardiasis are reportable communicable disease in British Columbia (BC). While past reports have highlighted outbreaks of shigellosis among the MSM population in BC (20,21,22), the epidemiology of STEIs, including shigellosis, has never been assessed in BC and is therefore not well understood. The objective of this study was to describe the epidemiology of these three infections in BC to determine if sexual transmission may be occurring and to identify the population and regions at risk of STEI.…”