Actinomyces genus
Microscopical image
• Member of the normal flora of the oral
cavity – early colonizer of dental plaque
• Gram-positive
• Filamentous branching rods
• Non-motile
• No endospore
• Anaerobe
Species
•
•
•
•
A. israelii
A. odontolyticus
A. naeslundii
A. viscosus
Pathogenesis I
Oral diseases
subgingival plaques & caries
gingivitis
A. odontolyticum involved in
progression of small caries lesions
Pathogenesis II
Actinomycosis
- after trauma of oral mucosa, caries,
gingivitis
- cervicofacial localisation (60-65 %)
- chronic granulomatous infection
- sulphur granules from sinus chanels
sulphur granules
cervicofacial
actinomycosis
1
Treatment
Mycobacterium genus
• Penicillin for several weeks
(chronic infection !)
• Aerobe
• Surgical excision and drainage
• High lipid content (60 %) in the cell wall
• Acid-fast rods
• Non-motile
• Non-sporing
Species
•
•
•
•
•
M. tuberculosis
M. bovis
M. africanum
M. leprae
Atypical mycobacteria
Pathogenesis
Transmission
M. tuberculosis from person to person by
respiratory aerosol (humans are the natural
reservoirs)
M . bovis ingesting contaminated milk
(reservoirs are cattle)
M. leprae prolonged contact (reservoirs are
only humans)
Atypical mycobacteria by inhalation from the
soil (there is no transmission from human to
human!)
Miliary tuberculosis
• Exudative lesions (acute inflammatory
response at the initial phase (site) of the
infection)
• Granulomatous lesions (tubercle) the
central area consist of giant cells
surrounded by fibrous tissue, later
central caseation necrosis and
calcification
2
Oral lesions of tuberculosis
Tuberculous lesions of the
oral mucosa
• The primary lesions are rare
• The secondary lesions are
ulceration of oral mucosa
tuberculous cervical lymphadenitis
periapical granulomas
maxilla or mandible infections
Laboratory diagnosis
• acid-fast (Ziehl-Neelsen) staining
• culture
Löwenstein-Jensen medium (doubling
time 18-20 hours) 6-8 weeks
• PCR
Treatment
• Multiple-drug therapy for 6-9 month with
Isoniazid (INH)
Rifampin
Pyrazinamide
Ethambutol
on Löwenstein-Jensen medium
3
Prevention
• BCG vaccine (bacillus Calmette-Guerin)
attenuated M. bovis
protects only against the fatal childhood
complications of tuberculosis (e.g.
meningitis tuberculosa)
• Tuberculosis free livestock
Geographical distribution of
leprosy
Mycobacterium leprae
• Cannot be cultured in vitro, grows on
footpads of mice or armadillos
• Two clinical types
– Lepromatous
– Tuberculoid
Lepromatous leprosy
• Progressive, malignant
• Multiple, erythematous, symmetrical ,
anaesthetic nodular skin lesions (saddle
nose, atrophy of the anterior nasal spine,
premaxillary bone recession are common)
• Slow symmetric nerve involvement
• Negative lepromin test
• Cell mediated immunity is deficient
Lepromatous skin lesions
Facies leonine
4
Oral lesions
• Ulcerated intraoral nodules
localisation: premaxillary gingivae, hard
and soft palates, uvula, tongue
• Dental deformities: discoloration of the
upper incisors
Tuberculoid leprosy
•
•
•
•
•
Nonprogressive, benign
Macular skin lesions
Asymmetric nerve involvement
Positive lepromin skin test
Intact cell-mediated immunity
Tuberculoid leprosy does not affect
directly the oral mucosa.
Laboratory diagnosis
Neisseriaceae
Specimen: biopsy from the skin lesions
• N. gonorrhoeae
acid-fast stain
• N. meningitidis
• commensal Neisseriae
N. gonorrhoeae
• By sexual intercourse (homo and
hetero)
-urogenital
-oral, nasopharyngeal
-rectal carriage
5
Pathogenesis
Pus from the urethra
• Localised
-urethritis in men
-cervicitis with vaginal discharge in women
oral inf: pharyngitis, painful ulceration of
lips, gingiva
• Disseminated
-arthritis
• In newborn infants purulent conjunctivitis
(ophthalmia neonatorum)
Ophthalmia neonatorum
Prevention
• Condom (safe sex)
• Prompt treatment of symptomatic
patients and their contacts
• Silver acetate drops (Crede-drops) or
erythromycin for newborns
Commensal Neisseriae
• N. subflava
• N. sicca
• N. mucosa
Non –pathogenic, the one of the earliest
colonizer of tooth surface, consume
oxygen during the early plaque
formation, facilitate growth of anaerobic
late colonizers
Actinobacillus
actinomycetemcomitans
• Small, short, straight or curved
coccobacilli
• Aerob with 5-10 % carbon dioxide
• Selective media is trypton-soy-serumbacitracin-vancomycin agar
6
Virulence factors
•
•
•
•
Endotoxin
Leucotoxin
Protease
Collagenase
Pathogenesis
• Endogenous infection (part of the normal flora
of the upper respiratory tract)
• Aggressive periodontal disease in adolescent
• Rapidly destructive periodontal disease in
adults
• Infective endocarditis, sepsis
• Abscesses
• Osteomyelitis
7