Lec (10) - Lactobacillus lecture note.pptx

Good lacto portion

1. Lactbacillus

2. Introduction Lactobacillus  is a genus of Gram-positive facultative anaerobic or  microaerophilic , rod-shaped, non-spore-forming bacteria They are a major part of the lactic acid bacteria group (i.e. they convert sugars to lactic acid).

3. Taxonomy The genus Lactobacillus currently contains over 180 species and encompasses a wide variety of organisms.   Lactobacillus  species can be divided into three groups: Obligately homofermentative (group I) including: L. acidophilus ,  L. delbrueckii ,  L. helveticus ,  L. salivarius Facultatively heterofermentative (group II) including: L. casei ,  L. curvatus ,  L. plantarum ,  L. sakei Obligately heterofermentative (group III) including: L. brevis ,  L. buchneri ,  L. fermentum ,  L. reuteri

4. Normal habitat In humans, they constitute a significant component of the  microbiota  at a number of body sites. In women,  Lactobacillus  species are normally a major part of the vaginal microbiota . Lactobacillus can also be found in the mouth, intestinal tract and in breast milk.

5. Benefits of Lactobacillus 1- In genital tract : Lactobacilli form part of the normal microbial flora of the vagina from puberty to menopause. They help to prevent vaginal infection by producing lactic acid.

6. Benefits of Lactobacillus continue 2- In food production: Some  Lactobacillus  species are used as starter cultures in industry for controlled fermentation in the production of yogurt, cheese, beer and other fermented foods, as well as animal feeds.

7. Benefits of Lactobacillus continue 3 - Clinical uses: Lactobacillus  species administered as a single probiotic agent is of no benefit in people with irritable bowel syndrome  or  Crohn's disease. When it is administered in combination with other probiotics, may help people with irritable bowel syndrome.

8. Pathogenicity They rarely cause diseases such as: Bacterial vaginosis Dental carries. Bacteremia, endocarditis, meningitis (rare)

9. Lab. diagnosis Microscopic Morphology Long, slender gram positive pleomorphic bacilli, Non-spore forming

10. Lab. Diagnosis (continue) Colony Morphology SBA Pinpoint α - hemolytic or gamma colonies Selective media: MRS agar & MRS broth de M an , R ogosa and S harpe . Biochemical tests: Catalase negative - Antibiotic Resistant to Vancomycin

11. MRS agar Appearance of Lactobacilli on MRS agar

12. Electron micrograph of Lactobacillus Long, slender bacilli