Lactobacillus acidophilus

Species of bacterium

Lactobacillus acidophilus is a species of gram-positive bacteria in the genus Lactobacillus. It is a homofermentative species, meaning it primarily produces lactic acid from the fermentation of carbohydrates. L. acidophilus is commonly found in the human microbiota, particularly in the gastrointestinal tract, oral cavity, and vagina.

Morphology and Physiology

Lactobacillus acidophilus is a rod-shaped bacterium that is typically 2-10 micrometers in length. It is non-spore-forming and non-motile. The bacterium grows optimally at temperatures around 37°C and at a pH of 5.5 to 6.0. L. acidophilus is an aerotolerant anaerobe, meaning it can survive in the presence of oxygen but does not require it for growth.

Lactobacillus acidophilus (Döderlein bacillus) under a microscope

Role in Human Health

Lactobacillus acidophilus is considered a probiotic, which means it can confer health benefits to the host when consumed in adequate amounts. It is often included in yogurt and other fermented foods as well as dietary supplements.

Gastrointestinal Health

In the gastrointestinal tract, L. acidophilus helps maintain a healthy balance of microflora, aids in digestion, and enhances the absorption of nutrients. It can also inhibit the growth of pathogenic bacteria by producing lactic acid and other antimicrobial substances.

Vaginal Health

L. acidophilus is a key component of the normal vaginal microbiota. It helps maintain an acidic environment, which is protective against infections such as bacterial vaginosis and yeast infections.

Simple columnar epithelium, where L. acidophilus may reside in the human body

Industrial and Commercial Uses

Lactobacillus acidophilus is widely used in the production of dairy products, such as yogurt and kefir, due to its ability to ferment lactose into lactic acid, which acts as a preservative and gives these products their characteristic tangy flavor.

Diagram of lactic acid fermentation

Applications in Medicine

L. acidophilus is used in probiotic supplements to support digestive health and immune function. It is also being studied for its potential role in preventing and treating various conditions, including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and urinary tract infections (UTIs).

Vaginal capsule containing Lactobacillus acidophilus

Safety and Side Effects

Lactobacillus acidophilus is generally considered safe for most people. However, individuals with weakened immune systems or underlying health conditions should consult a healthcare provider before using probiotic supplements.

Probiotic supplement containing Lactobacillus acidophilus

Related Pages

• Probiotic
• Lactic acid bacteria
• Microbiota
• Fermentation