33. Candida spp. and Actinomycetaceae family. Morphology, biology. Pathogenesis and diseases. Microbiological diagnosis. Therapy.

General Characteristics

• Gram-positive, non-spore-forming, non-acid-fast bacilli
• Characteristic branching filamentous morphology (may resemble fungi microscopically)
• Facultative or obligate anaerobes, grow best in reduced oxygen conditions
• Very slow-growing, colonies may take 5–10 days to appear

• Colonies on blood agar can appear “molar tooth” shaped
• Part of normal human flora – especially in:
• Oral cavity
• Gastrointestinal tract
• Female genital tract
• Disease occurs after disruption of mucosal barriers (e.g., trauma, dental procedures, IUD)

Pathogenic Species

• Actinomyces israelii – most common cause of human actinomycosis
• A. gerencseriae, Propionibacterium propionicus,– other species with variable pathogenicity

Pathogenesis

• Disease usually begins with mucosal damage (e.g., dental extraction, GI perforation, IUD use)
• Organism invades deeper tissues → chronic inflammation
• Forms suppurative granulomas, fibrosis, and multiple sinus tracts
• Sulfur granules (yellow, firm granules in pus) are a hallmark
• Spread is slow but invasive, can cross tissue planes and bones

Clinical Forms

1. Cervicofacial actinomycosis

• Most common; "lumpy jaw"
• Firm swelling in the jaw/neck area, discharging sinuses with sulfur granules
• Often follows poor dental hygiene or oral surgery

2. Thoracic actinomycosis

• Aspiration or contiguous spread
• Presents with cough, chest pain, fever; can involve pleura and chest wall sinuses

3. Abdominal actinomycosis

• Follows appendicitis, perforations, or surgery
• Presents as abdominal mass, fever, bowel obstruction, or fistulas

4. Pelvic actinomycosis

• Associated with intrauterine devices (IUD)
• Mimics pelvic inflammatory disease or ovarian tumors

5. CNS actinomycosis (rare)

• Brain abscess or chronic meningitis