Streptococcus

Streptococcus is a genus of gram-positive bacterium belonging to the phylum firmicutes and the order lactobacillales (lactic acid bacteria). Streptococcus is a d-lactic acid producing bacteria. Excessive production of d-lactic acid can lead to lactic acidosis.

Strep throat is caused by streptococcus.

D-Lactic Acidosis
Streptococcus and Enterococcus are two aerobic Gram positive intestinal bacteria that produce D-lactate. Elevated levels of D-lactic acid can lead to Lactic acidosis, characterized by the buildup of lactic acid in the bloodstream.

D-lactic acid bacteria linked to CFS symptoms
In a 2009 study, a significant increase of Gram positive facultative anaerobic faecal microorganisms were found in 108 CFS patients as compared to 177 control subjects, including Enterococcus faecalis and Streptococcus sanguinis.

Results suggest that when Enterococcus and Streptococcus spp. colonization in the intestinal tract is increased, the resulting excess D-lactic acid alters the pH and gut integrity, allowing the acid into the body. This in turn could explain neurocognitive and mitochondrial dysfunction symptoms in ME/CFS.

SIBO and Gut Dysbiosis
Streptococcus is often implicated in a condition called small intestinal bacterial overgrowth (SIBO), characterized by excessive bacteria in small intestines. SIBO is commonly found in ME/CFS, where symptoms often improve after treatment.

The most common bacterial species linked to SIBO include: Streptococcus, Escherichia coli, Lactobacillus and Bacteroides.

SIBO is a manifestation of microbiome dysbiosis, an imbalance of bacteria in the gut often accompanied by increased levels of aerobic bacteria, in particular Enterococcus and Streptococcus species.

Microbiota and bacterial overgrowth treatment
A 2015 study found significant symptom and overall sleep quality improvements among ME/CFS patients by treating Streptococcus and microbiota dysbiosis with Erythromycin.

A 2018 study including 44 adult ME/CFS patients (all with significant Streptococcus counts) showed improvements in total symptoms, some sleep, and cognitive symptoms following a 4-week Erythromycin + probiotic treatment. The antibiotic treatment was used to target the overgrowth of Streptococcus bacteria found in microbiota of ME/CFS patients. The idea was based on previous studies linking lactic acidosis and gut dysbiosis with symptoms of ME/CFS. And that d-lactic acid producing bacteria play a large role in both.

Results showed antimicrobial and probiotic treatment yielded concurrent reduction in enteric Streptococcus counts and improvement in some neurological symptoms.

Guttate Psoriasis
Guttate psoriasis is a type of psoriasis that shows up on your skin as red, scaly, small, teardrop-shaped spots. Streptococcal infection is one of the most common triggers of guttate psoriasis, specifically group A streptococcus.

In a large 2020 study, CFS patients with Human Leukocyte Antigen (HLA) risk alleles were found to share the following autoimmune diseases, ordered by frequency:
 * 1) Hashimoto's thyroiditis/hypothyreosis,
 * 2) Psoriasis
 * 3) Rheumatoid arthritis
 * 4) Alopecia areata
 * 5) Crohn’s disease or ulcerative colitis

Streptococcus and EBV Reactivation
Group A streptococci activate B cells via TLR2 and can trigger lytic reactivation of Epstein-Barr virus (EBV) in tonsils.

Learn more

 * Streptococcal infections - Merck manuals