1. © 2008, YCMOU. All Rights Reserved.1 Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. © 2008, YCMOU. All Rights Reserved.2 OC-SBT081-CP01-03 Introduction Programmes and Courses  SEP – SBT081 – Unit 01

3. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) ‏ Experience: 11 Years arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to:  Describe characteristic features of Mycobacteria.  Describe characteristic features of Rickettsias.

6. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.6 Introduction  The Mycobacteria and Rickettsias are highly pathogenic to human.  Mycobacterium tuberculosis causes tuberculosis which is the major global health hazard now a days.  Members of rickettsias are responsible for endemic typhus and typhus fever.  The common characteristic of both these genera is that the members of these genera are intracellular pathogens.  In this presentation we will learn about the characteristics of Mycobacteria and Rickettsias.

7. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.7 Mycobacteria-1  Mycobacteria contains aerobic slow growing bacteria such as Mycobacterium tuberculosis, Mycobacterium leprae.  The slow growth rate is attributed to the slow rate for building the mycolic acid riched cell wall of these organism.  They are slightly curved at the polar ends and slender bacilli measuring about 3 μ x 0.3 μ.  They are not stained by Gram's stain due to hydrophobic cell wall because of presence of mycolic acid.

8. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.8 Mycobacteria-2  Species of Mycobacteria:- Mycobacterium tuberculosis --  Causes pulmonary and extra pulmonary tuberculosis Mycobacterium leprae –-causes leprosy. Mycobacterium bovis – used for preparation of BCG vaccine. Mycobacterium avium –cause tuberculosis in birds Mycobacterium microti Mycobacterium ulcerans

9. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.9 Mycobacteria-3  Mycobacteria are stained by acid fast staining method and therefore they are also called as acid fast bacteria.  Their G+C content is slightly higher than 50%.  In laboratory the mycobacteria are culture onto Lowenstein jensen (LJ) medium and Middlebrook medium.  On these nutritive media the mycobacteria form visible culture in 14 days.

10. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.10 Mycobacteria-4  The pathogenic mycobacterium tuberculosis is identified on the basis of It cord formation observed on growth meduim surface. Slow growth Positive nitrate reductase test Niacin requirement for growth Acid fast characteristic  Presence of AFB ( acid fast bacilli ) in the patient smear is confirmed test for tuberculosis.  However the mycobacteria are isolated in laboratory to identify the species of mycobacteria and to test the drug susceptibility for the appropriate treatment of the patient.

11. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.11 Mycobacteria-5  The characteristic acid fast property of Mycobacteria are widely used to diagnose infections caused by them. Fig: Acid fast stained Mycobacterium tuberculosis

12. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.12 Mycobacteria-6  The tuberculosis caused by Mycobacterium tuberculosis is treated with isoniazid (isonicotinic acid hydrazide or INH) which is analog of nicotinamide required by Mycobacteria for the synthesis of mycolic acid.  The INH inhibit the normal synthesis of cell wall of mycobacteria leading to loss of cell wall integrity and ultimately death of the cell.  The other drug used for the treatment of tuberculosis is rifampin.  Both these drugs are used in combination to prevent the emergence of multi drug resistant strains of Mycobacteria.

13. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.13 Mycobacteria-7  Mycobacterium leprae is the causative agent of leprosy(also known as Hansen's disease) in humans.  Mycobacterium leprae can not be cultivated on the artificial media like mycobacterium tuberculosis.  Mycobacterium leprae are cultivated in animal, armadillos whose lower body temperature (30 °C )and his susceptibility to the microorganism favor the growth of these bacteria.  The leprosy is treated with the combination of dapsone, rifampin and clofazimine.

14. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.14 Rickettsias-1  The Rickettsias are very minute, slightly bigger than small pox virus measuring 0.3 μ x 1.0 μ in dimension.  They are Gram negative, obligate intracellular, aerobic and non motile parasite.  Due to leaky cytoplasmic membrane to NAD +, they grow in the cytoplasm of cells.  Based upon the rRNA sequences, they are classified into Proteobacteria.  To observe them under microscope, they are stained with Giemsa stain since they stained very weakly with Gram's stain.

15. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.15 Rickettsias-2  There are three medically important species of Rickettsias which cause diseases to humans.  These species are Rickettsia rickettsii Rickettsia typhi Rickettsia prowazekii  All these three species enter the body through arthropod vectors ant get entry into the body cell when they are phagocytosed.  Since outside the body they are not very stable and die quickly, therefore the mode of transmission is through vector bites.

16. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.16 Rickettsias-3 Sr. No.OrganismsVectorsDiseaseReservoir 1. 2. 3. R. Rickettsii R. typhi R. prowazakii Hard tick, wood tick Rat flae, cat flae Human body louse Ricky mountain spotted fever Murine(endem ic) typhus Endemic typhus Ticks, Rodents Humans, squirrels Human,squirrels, squirrel flae Table: Different species of Rickettsias

17. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.17 Rickettsias-4  Rickettsias can not be cultivated on cell free artificial media.  Rickettsias are cultivated in the yolk sac of developing chick embryo.  Rickettsias are also grown on mouse fibroblast cell line, HeLa cell line, HEp-2 and Detroit 6 cell line.  Rickettsias are very slow growing microorganism.  The cell doubling time of Rickettsias is 8hrs.

18. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.18 What We Learn...  Microbiological characteristics of Mycobacteria and Rickettsias.  Cultivation methods of Mycobacteria and Rickettsias.  Medical important species of Mycobacteria.  Diseases caused by Mycobacteria and Rickettsias.

19. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.19 Critical Thinking Questions  Why Mycobacteria and Rickettsias cause chronic diseases?

20. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.20 Hints For Critical Thinking Questions  Both are intracellular parasites.  Both grow very slowly.

21. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.21 Study Tips  Book Title: Title:Microbiology Author: Author: Robert W Bauman Publication: Publication: Benjamin Cummings, San Francisco  Book Title: Title: Microbiology, An Introduction Author: Author: Tortora and et al. Publication: Publication: Pearson education, Singapore

22. © 2008, YCMOU. All Rights Reserved.22 End of the Presentation Thank You!