Outbreak of locally acquired azithromycin-resistant Shigella flexneri infection in men who have sex with men

Intercontinental dissemination of azithromycin-resistant shigellosis through sexual transmission: a cross-sectional study

“…The association of successful sub-lineages of the outbreak lineage with a highly-mobile azithromycin resistance-conferring plasmid is consistent with reports of azithromycinresistant MSM-associated shigellosis cases across the United States, Canada, and Australia. 15,20,21 This resistance has obvious implications for clinical management (azithromycin treatment failure has already been reported in the Netherlands 22 ) and public health surveillance, including the urgent need to develop suitable clinical susceptibility breakpoints and resistance testing for azithromycin. 20,21 In addition to these specific and immediate implications for the treatment and management of MSM-associated shigellosis, the association with azithromycin resistance represents a disconcerting evolutionary response to antimicrobial selection pressures in a bacterial pathogen.…”

“…5 As well as continued reports in Northern America, 6-8, 11, 12 MSM-associated shigellosis outbreaks have also been reported in Oceania, Asia and Europe. 4,[13][14][15] Despite its importance to the epidemiology of shigellosis in high income countries, outbreaks of MSM-associated 6 shigellosis are frequently investigated with only basic microbiological subtyping and as small-scale epidemics in geographically restricted areas, with no investigation into possible connectivity with contemporaneous outbreaks in other countries.…”

“…9,16 The outbreak serotype (3a) has also been reported as having replaced S. sonnei in Canadian MSM outbreaks, and has been identified in MSM-associated shigellosis in Australia. 4,12,15 In the UK, the outbreak serotype is now considered endemic and is responsible for the majority of flexneri shigellosis nationwide, having replaced S. flexneri 2a as the most common serotype (though is still largely restricted to MSM). 4 To further investigate this growing public health concern, we collected over 300 clinical isolates of S. flexneri 3a.…”

Culture‐positive shigellosis cases are epidemiologically different to culture‐negative/PCR‐positive cases

“…This finding may be partially related to health seeking behaviour of gay men and increased awareness of sexual transmission of shigellosis in Australia. 33 In the past decade, there have been several outbreaks of shigellosis among the gay community in Australia, 34,35 prompting © 2018 Sydney Local Health District media campaigns in NSW encouraging symptomatic people to present to health services for testing, 36 and therefore this may lead to higher shigellosis detection rates in this risk group. In addition, the finding that culture-negative cases were more likely to be acquired overseas and were clinically less severe may relate to detection of EIEC in the culture-negative/PCR-positive group, in line with published evidence suggesting that E.coli versus Shigella was the cause of travellers' diarrhoea for residents of southern hemisphere countries for 35% vs. 5% of specimens tested globally.…”

Azithromycin Resistance in Shigella spp. in Southeast Asia

“…Recently updated CLSI guidelines suggest epidemiological cutoff values (ECVs) of MICs of ≥16 mg/liter and ≥32 mg/liter to the categories non-wild-type S. flexneri and S. sonnei , respectively ( 16 ). Data supporting these guidelines are limited and principally originate from reports of an international outbreak of S. flexneri serotype 3a among men who have sex with men (MSM) ( 17 – 19 ). Here, we aimed to assess the frequency and mechanisms of Shigella species isolates with decreased susceptibility to azithromycin in Southeast Asia, a setting where fluoroquinolone and third-generation cephalosporin resistance has become common.…”