1. Bacillus Corynebacteria Listeria, etc
GRAM POSITIVE BACILLI
Bacillus
Corynebacteria
Listeria, etc

2. Clinically important Gram positive bacilli
Spore forming
Bacillus
Non spore forming
Corynebacterium
Listeria
Bacilli w/ branching filaments
Actinomyces
Nocardia

3. BACILLUS
Bacillus anthracis
Bacillus cereus

4. Bacillus anthracis Large bacilli of 1-3 m
Single or paired in clinical isolates
In vitro – prominent capsule
Highly resistant spores

5. Gastrointestinal anthrax
Cutaneous anthrax
About 20% mortality
Virulence factors
Capsule (antiphagocytic)
Toxin (oedema & death)
Inhalation anthrax
High mortality
Gastrointestinal anthrax
High mortality

6. Anthrax - Epidemiology

7. Anthrax - Diagnosis Specimen Laboratory investigation
Aspirate or swab from cutaneous lesion
Blood culture
Sputum
Laboratory investigation
Gram stain
Culture
Identification of isolate

8. Anthrax – treatment and prevention
Penicillin
Tetracycline /chloramphenicol
Erythromycin,Clindamicin
Prevention
Vaccination of animal herds
Proper disposal of carcasses
Active immunisation with live attenuated bacilli

9. Bacillus cereus Large, motile, saprophytic bacillus
Heat resistant spores
Pre formed heat and acid stable toxin (Emetic syndrome)
Heat labile enterotoxin (Diarrhoeal disease)
Lab diagnosis – Demonstation of large number of bacilli in food

10. Bacillus cereus clinical presentation Gastroenteritis EMETIC FORM
DIARRHOEAL FORM
Incubation period > 6 hours
Diarrhoea
Lasts hours
Incubation period < 6 hours
Severe vomiting
Lasts 8-10 hours

11. CORYNEBACTERIA
Causes localized inflammation (pseudomembrane, greyish white exudate ) and generalized toxaemia
Prevalent in baby’s after 3-6 months, very high in young children

12. Morphology Gram+ve/ palisade/Chinese letter arrangement
Irregular swellings at one end -club shaped.
Corynebacteria tend to pleomorphism in microscopic and colonial morphology.

13. Culture characteristics
On blood agar Small granular & gray with irregular edges and may have small zones of hemolysis.
Also grow on Loeffler's serum slope
On blood telurite agar (black colonies)

14. Important species Corynebacterium diphtheriae
Normal flora of nasopharynx in about 10%
Some may cause Diphtheria
Diptheroids
Normal flora of skin, contaminants of samples
Can cause disease in ‘compromised’ host
C. ulcerans C. haemolyticum C. jeikeium

15. Epidemiology Rare in developed countries/
Disease of third world countries
Still highly prevalent in the former Soviet Union.
Spread through droplets.
Nasal carriers are very dangerous

16. Types of Diphtheria Faucial Laryngeal Nasal Conjunctival Vulvovaginal
Otitic
Cutaneous around the mouth and the nose

17. Pathology
Toxin is absorbed in the mucus membrane and causes destruction of epithelium and causes a superficial inflammatory response.
Necrotic epithelium becomes embedded in exuding fibrin and red and white cells, with bacteria.
Grayish pseudomembrane is formed over the tonsils and pharynx and larynx.

18. Pathology Removal of pseudomembrane - capillary damage and bleeding..
Regional lymphadenopathy with marked edema of the neck within the membrane bacilli produce toxin.
This results in distant toxic damage - parenchymatous degeneration, fatty infiltration & necrosis in heart muscle liver kidney & adrenals.

19. Diagnosis
Direct smear - Albert's stain
Culture - Loffler's serum slope/blood agar/blood telurite agar
Check the toxigenicity
Animal inoculation - Guinea pigs/rabbits - Death within 96 hrs
Elek’s test

20. Elek's plate test
Filter paper with antitoxin Precipitation
Strain

21. Management Patients 2. Contacts 3. Community – immunization
Isolation of the patient
Bed rest
Antibiotic treatment (Penicillin/erythromycin/teracycline/rifampicin/clindamycin )
Antitoxins (horse serum)
2. Contacts
Immunize (toxoid)
Prophylactic antibiotic – erythromycin
Swab nose and throats of contacts
3. Community – immunization

22. Anti-diphtheretic serum
DIPHTHERIA
DIAGNOSIS
Clinical suspicion
Swab for culture
Toxin production
PREVENTION
Immunization
(toxoid)
TREATMENT
Penicillin
Anti-diphtheretic serum
Maintaining airway
Supportive

23. Listeria monocytogenes

24. Clinical Manifestations
Listeriosis is a serious disease for humans, with a mortality greater than 25 percent.
Two main clinical manifestations, sepsis and meningitis.

25. Characteristics
Small, gram-positive rods, which are sometimes arranged in short chains.
Flagella are produced at room temperature rather than at 37° C.
A particular property of L monocytogenes is the ability to multiply at low temperatures. Bacteria therefore can accumulate in contaminated food stored in the refrigerator.

26. Pathogenesis
Listeria monocytogenes is presumably ingested with raw, contaminated food.
An invasion factor secreted by the pathogenic bacteria enables them to penetrate host cells of the epithelial lining.
Normally, the immune system eliminates the infection before it spreads. If the immune system is compromised, however, systemic disease may develop. 

27. Pathogenesis
Listeria monocytogenes multiplies not only extracellularly but also intracellularly within macrophages after phagocytosis and even within parenchymal cells which are entered by induced phagocytosis.
Survival within the phagosomes and eventual escape into the cytoplasm are mediated by a toxin, which also acts as a hemolysin.

28. Host immune response
Because it multiplies intracellularly, L monocytogenes is largely protected against humoral immune factors such as antibodies,
The effective host response is cell- mediated, involving both CD4+ (T-helper) cells and direct lysis of infected cells by CD8+ (cytotoxic) T lymphocytes.

29. Epidemiology
Listeria species are found in living and nonliving matter. Various foodstuffs of vegetable and animal origin are sources of infection.
Most human cases of listeriosis develop in immunocompromised hosts: newborns, old people, cancer patients, and transplant recipients.
Outbreaks of listeriosis are due mainly to a common source of contaminated food.
Listeriosis also may be transmitted congenitally across the placenta. The immunocompetent mother suffers at worst a brief, flu-like febrile illness, but the fetus, whose defense system is still immature, becomes seriously ill.

30. Diagnosis
Listeria monocytogenes is implicated when monocytosis is observed in the peripheral blood as well as the cerebrospinal fluid.
Early diagnosis may be obtained by finding pleocytosis with Gram-positive rods in a Gram stain of smears of the cerebrospinal fluid.
Final proof is obtained by culture.
Serologic tests are highly unreliable.

31. Control
Hygienic food processing and storage may reduce the risk of listeriosis.
Individuals in high-risk groups (i.e., immuno-compromised individuals and pregnant women) should avoid uncooked food or should at least marinate salads for a long time in a vinegar-based dressing to kill adherent bacteria.
Antimicrobial agents are the mainstay of treatment. Most of the common antibiotics, except cephalosporins, are active against L monocytogenes in vitro. High doses for prolonged periods are indicated.

32. Erysipelothrix Rhusiopathiae
Clinical Manifestations
The most common human infection by E rhusiopathiae is erysipeloid, a well-defined, violet or wine-colored inflammatory lesion of the skin of the fingers or hand .
Itching is typical. Infrequently, septicemia develops, followed by various organ manifestations such as endocarditis or arthritis without fever.

33. Erysipelothrix Rhusiopathiae
Structure and Classification
Erysipelothrix rhusiopathiae is a slender, Gram-positive rod similar to L monocytogenes. 
They grow on routine culture media under aerobic conditions, but preferentially in a CO2 atmosphere.
In contrast to L monocytogenes, they are nonmotile, nonhemolytic, and catalase negative.
The production of H2S is highly indicative.

34. Erysipelothrix Rhusiopathiae
Pathogenesis
A minor skin injury may facilitate the penetration of E rhusiopathiae after contact with infected material. After an incubation of 1 to 4 days the local lesion develops; spontaneous recovery occurs in 2 to 3 weeks. Septicemia has been observed without previous local lesions so that an oral infection is assumed. Endocarditis may develop in a few cases.

35. Erysipelothrix Rhusiopathiae
Epidemiology
Erysipelothrix rhusiopathiae is found in mammals, poultry, and fish.
Individuals who have occupational exposure to such animals (i.e., farmers, veterinarians, slaughterhouse workers, and fish handlers) are at risk.

36. Erysipelothrix Rhusiopathiae
Diagnosis
Since there is no wound, a swab is not useful. Bacteria can be cultured from a biopsy of the progressing, inflamed edge of the lesion.
Blood culture is indicated in the setting of sepsis and endocarditis.
Control
Penicillin is the drug of choice to treat serious infections. Since local skin infection is self-limited, therapy is not essential.

37. ACTINOMYCETES (FACULTATIVELY ANAEROBES)
Fermentative gp: Actinomyces, Arcanobacterium and Rothia
Oxidative gp : Actinomadura (actinomycetoma), Nocardia (nocardiosis), Streptomyces and related species.

38. Actinomycosis A. israelii – the commonest A .meyeri A.naeslundii
A.odontolyticus
A. viscosus

39. 6. Actinomyces israelii Has branching filaments Facultative anaerobes
Normal flora of oral cavity
Causes ‘Actinomycosis’ characterised by multiple abscess and granuloma formation
Tissue destruction, fibrosis and sinus formation

40. ACTINOMYCOSIS Mostly in cervico-facial region Endogenous infection
Can get
Thoracic actinomycosis (aspiration)
Pelvic actinomycosis (IUCD)
Rarely haematogenous spread
Treatment
Surgical
Long term penicillin

41. Diagnosis Specimens – open biopsy, aspiration material
Sulphur granules (yellowish myecelial masses)
The discharge should mix with sterile saline in a universal bottle and allow to stand, particles will separate out.

42. Place between 2 slides
Crush and gram stain
Gram positive branching filaments

43. ACTINOMYCOSIS

44. 7.Nocardia asteroides Branched, strictly aerobic bacillus
Environmental saprophytes (exogenous infection)
Lightly acid-fast
Uncommon causes of opportunistic pulmonary disease
Causes primary post-traumatic or post-inoculation lung disease

45. Cutaneous nocardiasis