Vitamin D and Streptococci: The Interface of Nutrition, Host Immune Response, and Antimicrobial Activity in Response to Infection
Infectious Diseases, https://dx.doi.org/10.1021/acsinfecdis.0c00666
Miriam A. Guevara, Jacky Lu, Rebecca E. Moore, Schuyler A. Chambers, Alison J. Eastman,
Jamisha D. Francis, Kristen N. Noble, Ryan S. Doster, Kevin G. Osteen, Steven M. Damo,
Shannon D. Manning, David M. Aronoff, Natasha B. Halasa, Steven D. Townsend,* and Jennifer A. Gaddy*
"Streptococcus pneumoniae. Streptococcus pneumonia, also referred to as pneumococcus, causes up to 4 million cases of illness within the United States and 450,000 hospitalizations per year"
- Pneumonia and low vitamin D - many studies
- Streptococcus is one of the causes of Pneumonia
Another study:Vitamin D Compounds Are Bactericidal against Streptococcus mutans and Target the Bacitracin-Associated Efflux System  PDF
 Download the PDF from sci-hub via VitaminDWiki
Type of Vitamin D
Streptococcus species are common causes of human infection. These Gram-positive, encapsulated bacterial pathogens infect diverse anatomic spaces, leading to infections including skin and soft tissue infection, endocarditis, pneumonia, meningitis, sinusitis, otitis media, chorioamnionitis, sepsis, and even death.
Risk for streptococcal infection is highest in low- and middle- income countries where micronutrient deficiency is common.
Epidemiological data reveal that vitamin D deficiency is associated with enhanced risk of streptococcal infection and cognate disease outcomes. Additionally, vitamin D improves antibacterial defenses by stimulating innate immune processes such as phagocytosis and enhancing production of reactive oxygen species (oxidative burst) and antimicrobial peptides (including cathelicidin and lactoferrin), which are important for efficient killing of bacteria. This review presents the most recent published work that studies interactions between the micronutrient vitamin D, the host immune system, and pathogenic streptococci as well as comparisons with other relevant infection models.
INTRODUCTION
Vitamin D is a secosteroid, a subclass of steroids with a broken ring structure, which regulates calcium and phosphorus homeostasis in a variety of organisms and maintains the skeleton in vertebrates. Extraskeletal functions of vitamin D have become apparent as studies have implicated vitamin D in cellular proliferation, differentiation, and immune system regulation.1 Studies of vitamin D deficiency and supplementation revealed its protective role against hypertension, infections, autoimmune diseases, cardiovascular diseases, diabetes, and some cancers in addition to its antirachitic activities.1
The genus Streptococcus contains both commensal bacteria that are part of the human microbiota in nearly every part of the human body and also several important human pathogens. Individual species in this genus are capable of causing invasive infection at every stage of human life from the perinatal period to advanced age. Among different age cohorts, streptococcal species cause diverse infections from skin and soft tissue infections to meningitis and endocarditis.
Vitamin D deficiency is quite common, and prior studies have suggested an association between the frequency and severity of streptococcal infections in individuals that are deficient in vitamin D.1,2 In this review, we will comprehensively cover vitamin D physiology with a focus on how vitamin D’s immunomodulatory activity impacts the pathogenesis of streptococcal infections and how vitamin D supplementation may play an important role to improve perinatal health outcomes as a common manifestation of streptococcal infection.