Group B streptococcal colonization in elderly women.

Area of Science:

• Microbiology
• Infectious Diseases
• Geriatrics

Background:

• Invasive Group B Streptococcus (GBS) disease incidence is rising in non-pregnant adults, particularly the elderly and immunocompromised.
• Vaginal colonization by GBS is common, but data in the elderly are limited, leaving a knowledge gap on prevalence trends.
• This study addresses the increasing GBS infections by investigating vaginal colonization in women over 60.

Purpose of the Study:

• To determine the rate of GBS vaginal colonization in women over 60 years old.
• To compare risk factors for invasive GBS disease in colonized versus non-colonized elderly women.
• To analyze GBS clusters for specific phenotypic and genotypic patterns in this population.

Main Methods:

• A prospective, observational, cross-sectional study conducted over three years (2017-2019) in two Swiss teaching hospitals.
• Vaginal swabs were collected from women over 60 during routine examinations for GBS screening.
• Isolates underwent characterization for antibiotic resistance, serotype, and sequence type (ST).

Main Results:

• The GBS positivity rate in elderly women was 17% (44/255), comparable to pregnant women.
• No association was found between participant characteristics, known risk factors, and GBS colonization.
• Prevalent serotypes included III (33%) and V (31%); ST1 and ST19 were common (11% each).
• Macrolide and clindamycin resistance was higher in ST1 isolates.

Conclusions:

• The rate of GBS vaginal colonization in elderly women is similar to that observed in pregnant women.
• Current risk factors for invasive GBS disease do not appear to predict colonization in the elderly.
• Further research into GBS epidemiology in aging populations is warranted.