1. Mycobacterium is an acid-fast genus that includes M. tuberculosis and non-tuberculous mycobacteria (MOTT). M. tuberculosis causes tuberculosis in humans and animals. 2. Bacillus includes B. anthracis, which causes anthrax, and B. cereus, which can cause food poisoning. 3. Clostridium includes C. perfringens, C. tetani, and C. chauvoei. C. perfringens causes gas gangrene and food poisoning. C. tetani causes tetanus. C. chauvoei causes blackleg in cattle.

1. AFB &SELECTED GRAM POSITIVES BLS 206

2. GENUS: MYCOBACTERIUM Classification – -Family Mycobacteriaceae -1 genus of medical importence = Mycobacteria -All are slow growing -All are acid-fast and contain large amounts of lipids intheir cell walls -Tubercle bacilli = M. tuberculosis, M. africanum, andM. bovis

4. The Mycobacteria are divided into 4 groups (Runyon groups) based on growth rate and pigmentation:Photochromagens: - are non-pigmented when grown in the dark. - produce photoactivated pigments upon exposure to light e.gM. kansasii, M. marinum, M. asiaticum, M. simiae

5. 2.Scotochromogens: -Produce deep yellow to orange pigments when grown in light or dark, - The color deepens upon two weeks exposure to light e.gM. gordonae, M. scrofulaceum, M. szulgai, M. xenopi. 3. Nonphotochromogens: -May produce pigment ranging from white to yellow, -The pigment does not intensify upon exposure to light.e.g. M. tuberculosis. M. avium, M. intracellulare, M. terrae, M. ulcerans. 4. Rapid growers: - organisms that form colonies within seven days.eg. M.phlei, M. smegamtis, M. fortuitum, M. chelonei.

7. Acid fast

10. Several acid fast stains that may be used:1. Ziehl-Neelsen: -uses heat to get the primary stain of carbolfuchsin to penetrate the cell wall; - acid alcohol destaining; - methylene blue as the counterstain.

13. Acid-fast bacilli

15. Most grow on simple media.

16. For primary isolation complex media should be used – Use of a nonselective, a selective and possibly a liquid media is recommended. Nonselective -May be egg or agar based. - May include malachite green to suppress growth of contaminating bacteria. Lowenstein-Jensen -egg based; -Colonies grow in 18-24 days. b. Middlebrook 7H10 and 7H11 – agar based; - colonies grow in 12-14 days.

17. 2. Selective media: – Consists of one of the nonselective media plus added antimicrobial agents (malachite green, cyclohexamide, and nalidixic acid are often used) -The colonies of M. tuberculosis on the solid media are rough, dry, granular, nonpigmented to buff colored colonies. 3. Liquid media: - Media usually contains tween 80 and albumin and the organisms will grow faster than on solid media NB: Most Mycobacteria grow best in 5-10% CO2 and at 35-370 C.

19. Pigmentation and photoreactivity

20. Further biochemical testing includes:Niacin reduction -M. tb. Is nitrate reduction+ and – for catalase at 680 C 2. Tween hydrolysis, 3. Arylsulfatase production, 4. Tellurite reduction, 5. Salt tolerance, and 6. Pyrazinamidase production

21. M. tuberculosis culture

23. interfees with mitochondrial function in mice and

24. plays a role in the development of granulomatous lesions

25. Iron capturing ability – required for survival inside phagocytes

27. In cattle- pulmonary d’se with involvement of associated lymph nodes.

28. Viscera and bone infections- occur in human

29. Chickens- resistant.

31. Other birds-Yes

32. Not all infected chickens show gross lesions.

33. Water fowls – resistant

34. In swine- disease found in lymph nodes of the head.

35. Cattle refractory but sensitized

36. Sporadic cases in horses, dogs and cats

39. Heat-sensitive

44. LABORATOY DIAGNOSIS 2. Microscopy: – Ziehl-Neelsen Stain – Fluorescent dyes 3. Culture: – Decontamination: – Lowenstein Jensen medium 4. Nucleic Acid Methods:

45. FAMILY: BACILLIACEAE HOZA, A. S

47. I. Bacillus anthracis •Causative agent of Anthrax. Distinctive Properties • Large, Square - ended Rods, Arranged in Chains. • Non-Motile. • Spores: • Capsule: – Purple Stained >> McFadyan's Method (Polychrome Methylene Blue). • Colonies on BA: "Medusa Head Appearance"

48. Bacillus anthracis

49. PATHOGENESIS • Capsule > Invasiveness – D-glutamicacid • Exotoxin (Plasmid mediated) i. Protective Factor (Antigen). ii. Oedema Factor. iii. Lethal Factor. Blocks the AdenylCyclase Pathway > Increases vascular Permeability > Shock

50. LABORATORY DIAGNOSIS: • Specimens obtained from: a malignant pustule, sputum, blood. - Gram stain + fluorescent-antibody stain. - Motility - Capsule formation: Sodium bicarbonate +CO2 - String-of-pearls reaction: - Mouse test: - API >> Demonstration of Abs to the organism:

51. Bicarbonate agar and blood agar plate cultures of Bacillus anthracis

52. Negative encapsulation: Blood agar and bicarbonate agar plate cultures of Bacillus cereus

53. • TREATMENT – Penicillin, Ciprofloxacin • IMMUNIZATION –Animals > Live spore vaccine (Sterne strain) – Workers at Risk of Exposure > Anthrax Vaccine Absorbed (AVA) >> “Alum precipitated toxoid”

55. PATHOGENICITY: >> Due to an Enterotoxin. • Also Causes Disease in Patients with Underlying Disease. TREATMENT: >> Tetracycline, Erythromycin. • iii. B. subtilis: • iv. B. stearothermophilus.

56. 2. GENUS: CLOSTRIDIUM

59. Fermentative

64. Some spp are found in the GIT

67. Clostridium perfrigens Synm: C. welchii. Disease:enterotoxemia Occurrence: C. perfrigenstype A more widespread, present in air, soil, dust, manure, water of lakes, streams, and rivers. Has been isolated from vegetables, milk, cheese, canned food, fresh meat, shellfish and mollusks.

68. FOOD POISONING: • Cl. perfringens Type A >> Enterotoxin. > Acute Abdominal Pain and Diarrhoea.

70. Gram stain of Clostridium perfringens

71. Exudate smear of Clostridium perfringens

72. Tissue smear of Clostridium perfringens

73. DISEASE: • Clostridialmyonecrosis. • Less severe wound infections. • Food poisoning.

75. Blood agar plate with Cl. Perfringenscharacteristic double zone of hemolysis

76. Clostridium chauvoeisynonym: C. feseri Disease: blackleg Wide spread, found in intestine and in normal tissues Toxins α toxin: hemolysin, necrotoxin ß toxin: deoxyribonuclease γ toxin: hyaluronidase ∆ toxin: hemolysin

77. Phathogenicity Ruminats: Blackleg (cattle 4 months to 2yr)- ingestion/endogenous, sheep and goats- wounds lession dry, dark, with gas bubles, and a rancid odor, there may be bacteremia. Immunity: Formalized whole-broth cultures- life long Recovery from disease—renders the animal immune for life

79. LABORATORY DIAGNOSIS: • Important: Diagnosis of Clostridium MyonecrosisShould Be Rapid and Made on Clinical Grounds. Direct Smear and Gram Stain of Material from Deep Within the Wound. ii. Culture: Tissue Aspirates or Deep Swabs Taken from Affected Muscle.

80. TREATMENT: • Clostridium myonecrosis: Surgical removal of all infected and necrotic tissue. ii. Antibiotic and Antitoxin therapy. iii. Adminstration of hyperbaric oxygen.

81. Clostridia that may be associated with gas gangrene: • Cl. perfringens Type A • Cl. Septicum • Cl. novyi Type A • Cl. Histolyticum • Cl. Sordellii

84. Nonspasmogenic toxin

86. Toxin is elaborated after spore germination.

87. Predisposing factors:

91. Blood Agar plate with C. botulinum

92. VIRULENCE FACTORS • Botulinum Toxin >>> Neurotoxin. – Serologically 8 types of Toxins >>A, B, C1, C2, D, E, F & G. > Affect the Cholinergic System > Blocks the Release of Acetylcholine (at Points in Peripheral Nervous System).

94. TREATMENT & PREVENTION Important: Specific Treatment should begin as quick as possible. >Polyvalent Antitoxin >>> Immediately. >Physiological support >NEVER Use a swollen or defective can.