Spore forming bacteria - bacillus and clostridia

This is a series of lectures on microbiology, useful for undergraduate medical and paramedical students

1. Spore forming bacteriaSpore forming bacteria
Dr. Dr. AshishAshishJawarkarJawarkarM.D.M.D.

2. TypesTypes
•Aerobic –Bacillus
•Anaerobic –clostridia
Bacillus –two major species
B. Anthracis–causes Anthrax
B. Cereus –food poisoning

3. B. B. AnthracisAnthracis
•Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

4. MorphologyMorphology
•Gram positive bacilli in chains
•Bacilli have characteristic squared ends
•Bamboo stick appearance
•Entire chain surrounded by polypeptide
capsule
•Spores donotstain by ordinary stain
•They are central –donotcause bulging

6. Mc Mc fadyeanfadyean’’ssreactionreaction
•Amorphous purplish material around
bacilli
•Represent capsular material

8. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

9. Growth Growth charcteristicscharcteristics
•Aerobe
•On culture –raised, dull opaque, grayish
white colonies –frosted glass
appearance
•Edge of colony is composed of interlacing
chains of bacilli looking like matted hair –
medusa head appearance
•When grown with Penicillin added –the
cells become large, spherical and look like
string of pearls

10. Frosted glassFrosted glass

11. Medusa headMedusa head

12. String of pearlsString of pearls

13. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

14. ResistanceResistance
•Bacilli stay in bone marrow and skin
of dead animals for about a week
•Normal heat fixation may not kill
bacteria in blood smears

16. •Spores are highly resistant to
chemical and physical agents
•Found in soil after 60 years
•Resistant to dry heat at 140 deg for
3 hours
•Resistant to boiling for 10 min
•They survive in 5% phenol for weeks

17. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

18. PathogenicityPathogenicityand virulenceand virulence
•Capsule –helps to escape
phagocytosis
•Toxin –leads to anthrax

19. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

20. EpidemiologyEpidemiology
•Seen in animal handlers –those who
carry skin/hides on back
•Hide porter disease

21. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

22. AnthraxAnthrax
•Agent for bioterrorism

24. •Active outbreak in India –in sheep –
near Tamilnadu-Andhrapradesh
border
•Causes cutaneousinfections and
meningitis

25. AnthraxAnthrax
•Usually an occupational disease –
contact with infected animals
•Types –cutaneous, pulmonary,
intestinal

26. CutaneousCutaneousanthraxanthrax

28. •Lesion called malignant pustule
•Central area is black due to necrosis
–eschar
•Resolves spontaneously

29. Pulmonary anthraxPulmonary anthrax
•Hemmorhagicpneumonia
•Hemmorhagicmeningitis
•Seen in people engaged in sorting
wool –woolsorters disease

31. Intestinal anthraxIntestinal anthrax
•Seen in communities that eat dead
animals
•Bloody diarrhoea

32. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

33. Lab diagnosisLab diagnosis
•Sample
–Skin –biopsy/materia
–Sputum
–Stool
•Gram stain
•Culture
•Special test –direct fluoroscentantibody
test
•PCR

34. •Morphology
•Growth characteristics
•Biochemical reactions
•Resistance
•Pathogenicityand virulence
•Epidemiology
•Diseases caused
•Laboratory diagnosis
•Treatment

35. B. CereusB. Cereus
•Cause of food poisoning
•Found in milk, cereals, spices, meat and
poultry
•Two types of food poisoning
–Acute –chinesefried rice –vomittingin 1-5
hrs after meal
–Chronic –After 8 hrs of ingestion
•Illnesses are mild –require no treatment

36. ClostridiaClostridia
•Gram positive, spore forming
•Anaerobic
–Clperfringens–gas gangrene
–Cltetani–tetanus
–Clbotulinum–food poisoning
–Cldifficile–acute colitis

37. •Clostridia –kloster-spindle

38. Gas gangreneGas gangrene
•Caused by Clperfringenstype A
•It is a rapidyspreading necrosis of
muscles
•Usually seen after extensive muscle
damage (contaminated) secondary
to trauma –road accidents, battle
field injury

39. Clinical featuresClinical features
•Increasing pain, edema and
tenderness of the affected limb
•Accumulation of gas

41. Lab diagnosisLab diagnosis
•Sample –muscle fragments or
necrotic debris
•Plated on appropriate culture media

42. TetanusTetanus
•Characterisedby tonic muscular
spasms, commencing at site and
slowly becoming generalised
•Disease follows injury too trivial to
be noticed
•Due to tetanospasmintoxin produced
by Cltetani

43. Different forms of tetanusDifferent forms of tetanus
•Generalized tetanus

44. Local tetanusLocal tetanus

45. Cephalic tetanusCephalic tetanus
•After a head injury or local infection
•Trismus–lock jaw

46. Neonatal tetanusNeonatal tetanus
•Infection follows unhygeinicpractices
after delivery
•Applying cowdungon umbilical
stump

47. •Diagnosis is clinical –by the time
symptoms appear, organism is no
longer present in lesion

48. TreatmentTreatment
•Human tetanus immunoglobulin –
can neutralize toxin

49. PreventionPrevention
•DPT vaccine

50. ClClbotulinumbotulinum
•Produces neurotoxin
•Causes paralysis
•Used in treating wrinkles

52. typestypes
•Food borne botulism
–eating food with pre formed toxin
–After 12 hrs of taking food
–Vomitting, constipation, difficulty in swallowing,
speaking, breathing
–Respiratory failure
•Wound botulism
–No gimanifestations
•Infant botulism
–Infants below 6 months
–Honey is an agent
–Poor feeding, pooling of oral secretions, loss of head
control

53. ClCldifficiledifficile
•Antibiotic associated diarrhoea
(clindamycin)
•Disrupts normal flora
•Psuedomembranous colitis

54. PseudomembranousPseudomembranous colitiscolitis

55. PseudomonasPseudomonas

56. P. P. aeruginosaaeruginosa
•Pseudo –false
•Monas–mono –single unit
•Slender gram negative bacillus with
polar flagellum

58. •Produces bluish green pigment –
pyocyaninon culture

59. •Very resistant to common antiseptics
and disinfectants like dettol
•Susceptible to glutaraldehydeand
phenols

60. •Most common infection –otitismedia
•In hospitals –wound infection, bed
sores, UTI following catheterisation
•Seen in equipments such as
respirators, endoscopes, bed pans,
lotions, eye drops