Group B streptococcal infection of the genitourinary tract in pregnant and non‐pregnant patients with diabetes mellitus: An immunocompromised host or something more?

Abstract

Group B Streptococcus (GBS), also known as Streptococcus agalactiae is a Gram-positive bacterium commonly encountered as part of the microbiota within the human gastrointestinal tract. A common cause of infections during pregnancy, GBS is responsible for invasive diseases ranging from urinary tract infections to chorioamnionitis and neonatal sepsis. Diabetes mellitus (DM) is a chronic disease resulting from impaired regulation of blood glucose levels. The incidence of DM has steadily increased worldwide to affecting over 450 million people. Poorly controlled DM is associated with multiple health comorbidities including an increased risk for infection. Epidemiologic studies have clearly demonstrated that DM correlates with an increased risk for invasive GBS infections, including skin and soft tissue infections and sepsis in non-pregnant adults. However, the impact of DM on risk for invasive GBS urogenital infections, particularly during the already vulnerable time of pregnancy, is less clear. We review the evolving epidemiology, immunology, and pathophysiology of GBS urogenital infections including rectovaginal colonization during pregnancy, neonatal infections of infants exposed to DM in utero, and urinary tract infections in pregnant and non-pregnant adults in the context of DM and highlight in vitro studies examining why DM might increase risk for GBS urogenital infection.

Association between glycemic control and group B streptococcus colonization among pregnant individuals with pregestational diabetes

“…This risk increases further with poor glycemic control: non‐pregnant individuals with poor glycemic control are more than four times as likely to be affected by invasive GBS disease compared with those with adequate glycemic control 31 . In pregnancy, the association between GBS colonization and diabetes has been previously demonstrated 2,27–29 . Adverse pregnancy outcomes, including preterm birth, chorioamnionitis, endometritis, sepsis, and wound infections are more frequent with invasive GBS infection 3–5,7,40 .…”

“…2,[27][28][29] Further, infants born to individuals with diabetes may have an increased risk of neonatal GBS infection and consequent infectious morbidity. 29 Outside of pregnancy, diabetes is associated with increased risk of infectious morbidity, including invasive GBS infection, and poor glycemic control has been associated with increases in this risk. [29][30][31][32] The relationship between glycemic control and GBS colonization in pregnant individuals with pregestational diabetes has not been previously explored.…”

Molecular epidemiology, drug resistance, and virulence gene analysis of Streptococcus agalactiae isolates from dairy goats in backyard farms in China

“…agalactiae ) is a species of Gram-positive chain-forming cocci, and is also called group B Streptococcus . It mainly affects humans ( Lannes-Costa et al., 2021 ; Nguyen et al., 2021 ; Tavares et al., 2022 ), cattle ( Keefe, 2012 ; Reyher et al., 2012 ; Kabelitz et al., 2021 ), and fish ( Alazab et al., 2022 ; Piamsomboon et al., 2022 ; Sapugahawatte et al., 2022 ). In dairy animals, S. agalactiae invades the mammary gland, which can lead to clinical or subclinical mastitis; as a result, a reduction in milk production of > 20% is common ( Keefe, 1997 ).…”

High Glucose Promotes Inflammation and Weakens Placental Defenses against E. coli and S. agalactiae Infection: Protective Role of Insulin and Metformin

“…GDM patients have higher vulvovaginal infection rates and vaginal dysbiosis rates in comparison to euglycemic women [ 8 , 10 ]. Epidemiologic evidence supports that, in diabetic and GDM pregnant women, the most frequent bacterium isolated from urogenital specimens is S. agalactiae [ 11 , 12 ], with a colonization-adjusted rate in pregnant women of 21–25% in North America and 18% worldwide [ 13 ]. Additionally, Escherichia coli is the leading cause of chorioamnionitis and urinary tract infections in pregnant women [ 14 , 15 , 16 , 17 , 18 ].…”