Streptococcus pyogenes infections with limited emm-type diversity in the homeless population of Brussels, 2016–2018

• Published in: International journal of infectious diseases 2019-04, Vol.81, p.52-56
• Main Authors: Dauby, Nicolas, Miendje Deyi, Véronique Yvette, Delforge, Valérie, Martiny, Delphine, Mekkaoui, Leila, Hallin, Marie, Mahieu, Romain, Bossuyt, Nathalie, Botteaux, Anne, Smeesters, Pierre R.
• Format: Article
• Language: English
• Subjects: Epidemiology; Homeless persons; Skin infections; Streptococcal m protein; Streptococcus pyogenes
• ISSN: 1201-9712; 1878-3511
• DOI: 10.1016/j.ijid.2019.01.026

•Homeless persons were over-represented among adults hospitalized with Streptococcus pyogenes infections.•The estimated incidence rate was 100 times higher for homeless people than for the non-homeless.•Skin abscesses were more frequent in the homeless group.•In the homeless group, four emm-types (64, 77, 83, and 101) accounted for 76.1% of the infections.•In the homeless group, the majority of the emm-types belonged to the D4 emm-cluster. 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). 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. 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. 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.