ACTINOMYCES

ACTINOMYCES

ACTINOMYCES SPP. ARE POTENTIALLY PATHOGENIC COMMENSALS OF MOUTH IN HUMANS & ANIMALS. MAJOR COMPONENT OF DENTAL PLAQUE AT PROXIMAL SITES OF TEETH.

THESE ARE GRAM POSITIVE PLEOMORPHIC BACTERIA, WHICH MAY SHOW BRANCHED FILAMENTS.

THEY ARE FACULTATIVE ANAEROBES.

MEDIA USED ARE - BRAIN HEART INFUSION

AGAR / BROTH, THIOGLYCOLLATE BROTH WITH 0.1-0.2% RABBIT SERUM.

PATHOGENIC SPECIES ARE – A. israelii, A. naeslundii, A. meyeri, A. odontolyticus, A. viscosus. ALL THE SPECIES ARE

COMMENSALS IN MOUTH, THEREFORE , ENDOGENOUS CAUSE OF DISEASE.

PATHOGENESIS-

ACTINOMYCOSIS IS A CHRONIC SUPPURATIVE DISEASE , CHARACTERIZED BY PERIPHERAL SPREAD TO CONTIGUOUS TISSUES,

RARE HAEMATOGENOUS SPREAD.

IT FORMS SINUS TRACTS , WHICH DRAINS THE LESIONS.

THE PUS CONTAINS COLONIES OF THE ORGANISM, WHICH ARE CALLED AS SULPHUR GRANULES.

THERE ARE THREE IMPORTANT SITES OF PRIMARY INFECTION IN ACTINOMYCOSIS.

1. CERVICOFACIAL- PRIMARY LESION IS USUALLY IN

THE MANDIBLE OR MAXILLA.

IT OCCURS BY DIRECT EXTENSION FROM A PERIODONTAL ABSCESS, NEGLECTED CARIOUS OR BROKEN TEETH, DENTAL EXTRACTION OR ACCIDENTAL FRACTURE OF JAW.

2. THORACIC-

IT OCCURS IN LUNGS AS A RESULT OF ASPIRATION OF HYPHAL FRAGMENTS OF ACTINOMYCES FROM TOOTH SURFACES OR DENTAL CARIES .

THE LESION IN THE LUNG MAY INVOLVE PLEURA AND PERICARDIUM.

IT SPREADS OUTWARDS THROUGH THE CHEST WALL PRODUCING MULTIPLE DRAINING SINUSES.

3. ABDOMINAL –

MOST OFTEN SEEN IN THE APPENDIX.

LABORATORY DIAGNOSIS- SPECIMENS: PUS, SINUS DISCHERGE, BRONCHIAL

SECRETIONS, SPUTUM OR INFECTED TISSUES ARE COLLECTED ASEPTICALLY.

THESE SPECIMENS CONTAIN SULPHUR GRANULES.

1. MICROSCOPY – PUS IS MIXED WITH STERILE

WATER. SULPHUR GRANULES SETTLE TO BOTTOM.

GRANULES ARE CRUSHED BETWEEN TWO SLIDES & STAINED WITH GRAM AND ZEIHL-NEELSEN STAIN USING 1% SULPHURIC ACID FOR DECOLOURISATION.

GRANULES ARE SEEN TO CONSIST OF GRAM POSITIVE HYPHAL FRAGMENTS 0.5- 1 µm IN DIAMETER SURROUNDED BY A PERIPHERAL ZONE OF SWOLLEN RADIATING CLUB-SHAPED STRUCTURES PRESENTING A SUN RAY APPEARANCE.

CLUBS ARE GRAM NEGATIVE & ARE OF HOST ORIGIN.

SULPHUR GRANULES & MYCELIA IN TISSUE SECTIONS CAN BE IDENTIFIED BY DIRECT FLUORESCENCE MICROSCOPY.

2. CULTURE- SULPHUR GRANULES ARE

WASHED THOROUGHLY IN STERILE NORMAL SALINE .

THEY ARE CRUSHED IN A DROP OF SALINE WITH A GLASS ROD.

THEN THEY ARE INOCULATED ON BRAIN HEART INFUSION AGAR,

BLOOD AGAR & IN THIOGLYCOLLATE BROTH.

THEY ARE INCUBATED BOTH AEROBICALLY & ANAEROBICALLY IN

5-10 % CO2 AT 35-37°C FOR UPTO 14 DAYS.

THE COLONIES ARE 0.5-2mm IN DIAMETER, WHITE TO GREY-WHITE, SMOOTH, ENTIRE OR LOBULATED RESEMBLING MOLAR TEETH.

GROWTH IS FURTHER CONFIRMED BY DIRECT FLUORESCENCE MICROSCOPY AND BIOCHEMICAL TESTS.

3. BIOPSY IN HAEMATOXYLIN AND EOSIN

STAINED SECTIONS, THE SULPHUR GRANULES ARE DEEPLY STAINED WITH HAEMATOXYLIN EXCEPT AT PERIPHERY WHICH IS STAINED BY EOSIN.

THE TISSUE REACTION IS A CHRONIC SUPPURATIVE, FIBROSING, INFLAMMATORY PROCESS.

TREATMENT-

SURGICAL REMOVAL OF AFFECTED TISSUE .

LARGE DOSES OF PENICILLIN UPTO

6 WEEKS. TETRACYCLINE MAY ALSO BE

USED.