Streptococcus pyogenes infections with limited emm-type diversity in the homeless population of Brussels, 2016-2018.
OBJECTIVES
The aim was to characterize the clinical features, outcomes, and strain diversity of laboratory-confirmed Streptococcus pyogenes (group A Streptococcus, GAS) infections among inpatients hospitalized at a tertiary level hospital in Brussels, Belgium, according to the patients' housing status (homeless vs. not homeless).


METHODS
Between August 2016 and January 2018, all patients hospitalized with a laboratory-confirmed GAS infection were prospectively enrolled and risk factors were recorded. GAS strains were characterized using emm-typing and emm-clustering in both inpatients and outpatients. Analyses were performed according to homelessness status.


RESULTS
During the study period, 48% (28/58) of adults hospitalized with a GAS infection at the tertiary hospital were homeless. The estimated incidence rate was 100 times higher for homeless persons. Skin abscesses were more frequent in the homeless group (21.4% vs. 3.3%) and mortality was high (10.7%). Limited emm-type diversity was found in this group, with four emm-types (64, 77, 83, and 101) accounting for 76.1% of the infections, and the majority of these emm-types belonged to the D4 emm-cluster. Pooled analyses of inpatient and outpatient strains indicated lower diversity in the homeless group.


CONCLUSIONS
The homeless are disproportionately affected by GAS and have a higher rate of abscesses and high mortality. The lower emm-type diversity and preferential infection with four emm-types likely reflects endemic circulation of GAS in this population. Preventive strategies are warranted in this fragile population.
['Dauby|Nicolas|N|', 'Miendje Deyi|Véronique Yvette|VY|', 'Delforge|Valérie|V|', 'Martiny|Delphine|D|', 'Mekkaoui|Leila|L|', 'Hallin|Marie|M|', 'Mahieu|Romain|R|', 'Bossuyt|Nathalie|N|', 'Botteaux|Anne|A|', 'Smeesters|Pierre R|PR|']
D000328:Adult D001425:Bacterial Outer Membrane Proteins D001530:Belgium D016000:Cluster Analysis D005260:Female D006703:Homeless Persons D006801:Humans D008297:Male D008875:Middle Aged D012874:Skin Diseases, Infectious D013290:Streptococcal Infections D013297:Streptococcus pyogenes
Streptococcus pyogenes Homeless persons Epidemiology Skin infections Streptococcal m protein