Changes in Group B Streptococcus Colonization among Pregnant Women before and after the Onset of the COVID-19 Pandemic in Brazil

Group B Streptococcus (GBS) is a leading cause of neonatal infections. The genitourinary and gastrointestinal tract of pregnant women are the main source of transmission to newborns. This work investigated the prevalence and characterized GBS from pregnant women in Rio de Janeiro, Brazil, comparing the periods before (January 2019 to March 2020; 521) and during (May 2020 to March 2021; 285) the COVID-19 pandemic. GBS was detected in 10.8% of anovaginal samples. Considering scenarios before and during the pandemic, GBS colonization rate significantly decreased (13.8% vs. 5.3%; p = 0.0001). No clinical and sociodemographic aspect was associated with GBS carriage (p > 0.05). A total of 80%, 13.8% and 4.6% GBS strains were non-susceptible to tetracycline, erythromycin and clindamycin, respectively. Serotype Ia was the most frequent (47.7%), followed by V (23.1%), II (18.4%), III (7.7%) and Ib (3.1%). An increasing trend of serotypes Ib and V, as well as of antimicrobial resistance rates, and a decreasing trend of serotypes II and III, were observed after the pandemic onset, albeit not statistically significant (p > 0.05). The reduction in GBS colonization rates and alterations in GBS serotypes and resistance profiles during the pandemic were not due to changes in the sociodemographic profile of the population. Considering that control and preventive measures related to the COVID-19 pandemic onset have impacted other infectious diseases, these results shed light on the need for the continuous surveillance of GBS among pregnant women in the post-pandemic era.

Biofilm production and distribution of pilus variants among Streptococcus agalactiae isolated from human and animal sources

Streptococcus agalactiae (group B Streptococcus, GBS) is a major pathogen in humans and animals. Pili and biofilm may be important virulence factors in this bacterial species. Here, biofilm production and the distribution of pilus variants among 134 GBS isolates from human and animal sources were evaluated. Biofilm production was significantly enhanced in 1% glucose-supplemented medium (p < 0.05). Using this medium, most GBS strains were strong biofilm producers. Biomass was mainly composed of proteins, followed by extracellular DNA, while polysaccharides represented a minor portion. All GBS strains presented at least one pilus variant. PI-2a was the most common among human GBS while PI-2b was the most common among animal isolates. Human GBS harboring PI-2b and animal GBS harboring PI-2a presented significantly reduced biofilm production (p = 0.0033). In conclusion, strong biofilm production seems to be a common characteristic in GBS, and association of the clinical source with the pilus variant may be crucial for this.