Filaments Notes

NOTES NOTES FILAMENTS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Gram ⊕ slender bacteria with ⊕ branches (atypical lung disease organisms, capable of affecting any body organ ▪ Atypical organisms → indolent disease → insidious growth → severe disease RISK FACTORS ▪ Immunodeficiency ▪ Corticosteroid use → iatrogenic immunosuppression SIGNS & SYMPTOMS ▪ Cough, dyspnea ▫ Indolent course ▫ Common in fever’s absence ▪ Other symptoms ▫ Dependent on organ systems affected by organism DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Localized alveolar infiltrate ▫ Homogeneous, non-segmental, cavitary appearance 382 OSMOSIS.ORG LAB RESULTS ▪ Tissue biopsy → histological OTHER DIAGNOSTICS Physical examination ▪ Pulmonary examination ▫ Auscultation: rhonchi (crackles), ↓ breath sounds ▫ Palpation: ↓ tactile fremitus ▫ Percussive dullness TREATMENT MEDICATIONS ▪ Antibiotics SURGERY ▪ Resection ▫ Medication non-responsive ▫ Large infections → significant dysfunction

Chapter 71 Filaments ACTINOMYCES ISRAELII osms.it/actinomyces-israelii PATHOLOGY & CAUSES Microbe characteristics ▪ ⊕ Gram stain ▪ Shape ▫ Filamentous, non-spore-forming, pleomorphic bacilli ▪ Metabolism ▫ Catalase negative, anaerobic/ microanaerobic bacilli ▪ Types ▫ 21 species found in humans ▫ Actinomyces israelii most common ▪ Locations ▫ Normal mouth (by two years old), gastrointestinal (GI) tract, female genitourinary tract flora PATHOLOGY Thoracic ▪ Pulmonary → pneumonia ▫ Oropharyngeal content aspiration → bacterial alveoli seeding → immune response, bacterial growth → pneumonia Abdominal & pelvic ▪ Gastrointestinal → appendicitis ▫ Preceding colonic mucosa perforation → unrecognized → months–year course → symptomatic infection ▪ Pelvic → female genitourinary infections ▫ Complicated abortions, infected intrauterine devices (IUDs), endometritis, tubo-ovarian abscess (TOA) RISK FACTORS ▪ Chronic granulomatous disease Cervicofacial ▪ Chronic tonsillitis, dental decay, periodontal disease, mastoiditis, otitis media ▪ Uncommon infection source ▪ Mucosal membrane violated → indolent, invasive disease ▫ Commonly co-occurs with another pathogen → micro-O2 Actinomyces environment ▫ Can burrow through soft tissue, bone → small abscesses, drainage tracts ▫ Abscesses: yellow sulfur-containing granules in granulomatous reactive material setting (bacteria found in microfilament tangles, surrounded by neutrophils) COMPLICATIONS TYPES Thoracic ▪ Pneumonitis Cervicofacial ▪ Osteomyelitis of mandible/maxilla ▫ Resident flora in periodontal pockets, carious teeth, dental plaque, tonsillar crypts Abdominal & pelvic ▪ Gastrointestinal ▫ Peritoneal, hepatic, pelvic infectious spread Thoracic ▪ Aspiration history Cervicofacial ▪ Deep neck tissue infection → retropharyngeal space → mediastinitis ▪ Meningitis → if sinus tracts to posterior neck, spinal cord OSMOSIS.ORG 383

SIGNS & SYMPTOMS Cervicofacial ▪ Lumpy jaw ▫ Usually in fever’s/other infectious signs’ absence ▪ Progression → oral mucosa, trismus sinus tract draining Thoracic ▪ Fever, cough > three day duration ▪ Auscultation ▫ Rhonchi ▫ ↓ breath sounds ▪ Palpation ▫ ↓ tactile fremitus ▪ Percussive dullness Abdominal & pelvic ▪ Gastrointestinal → appendicitis ▫ Asymptomatic colonic mucosa (micro) perforation → months–years prodrome → symptomatic appendicitis ▫ Nonspecific prodrome: chronic fever, weight loss, diarrhea, constipation, night sweats ▫ Appendicitis: nausea, vomiting, anorexia ▪ Pelvic → female genitourinary infections ▫ Painful abdominal, cervical examination ▫ Purulent vaginal discharge CT scan ▪ Abdominal, pelvic ▫ Disrupted tissue planes Colonoscopy ▪ Abdominal, pelvic ▫ Normal/thickened mucosal appearance, colitis, ulceration, nodular lesion, buttonlike appendiceal orifice elevation Bedside ultrasound ▪ Abdominal, pelvic ▫ TOA evaluation LAB RESULTS ▪ Cervicofacial ▫ Monoclonal antibody staining ▫ Polymerase chain reaction (PCR) of 16S rRNA Cultures (needle aspiration) ▪ Cervicofacial ▫ Histology: granulation tissues with neutrophils, foamy macrophages, lymphocytes, plasma cells (with surrounding fibrosis) ▪ Abdominal, pelvic ▫ Histology: granulation tissue surrounding oval, eosinophilic zones DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Thoracic ▫ Localized alveolar infiltrate: homogeneous; non-segmental, cavitary appearance; can extend past fissure lines → into chest wall Barium enema ▪ Abdominal, pelvic ▫ Luminal narrowing, fistualization, extrinsic compression 384 OSMOSIS.ORG Figure 71.1 Sulphur granules formed by Actinomyces organisms.

Chapter 71 Filaments OTHER DIAGNOSTICS History ▪ Thoracic ▫ May have community-acquired pneumonia diagnosis, treatment (without relief within 3–5 days) Physical examination ▪ Cervicofacial ▫ Lymphatic examination ▪ Thoracic ▫ Pulmonary examination TREATMENT MEDICATIONS ▪ Antibiotics ▫ Prolonged (weeks–months) penicillin V (oral)/penicillin G (intravenous) ▫ Amoxicillin (alternative) SURGERY ▪ Necrotic disease/especially large abscess formation cases NOCARDIA osms.it/nocardia PATHOLOGY & CAUSES ▪ Microbe characteristics ▪ ⊕ Gram stain ▪ Shape ▫ Filamentous, branch-forming, bacillus ▫ Branches → beaded appearance (delicate nature of stain → cocci/bacilli fragmentation) ▪ Metabolism ▫ Aerobic, catalase ⊕, urease ⊕ ▪ Types ▫ > 80 species ▫ Around 30 disease-causing in humans ▪ Locations ▫ Saprophyte (organic pathogen) → found in soil, house dust, water (fresh/salt), bathing pools PATHOLOGY ▪ Direct tissue inoculation ▫ Saprophyte → aerosolization common (↑ ↑ pulmonary infections) ▫ Soil/water contamination (contaminated food → GI disease, skin trauma → cutaneous disease, eye trauma → ocular disease) ▪ Facultative intracellular organism → requires innate host defense mechanisms ▫ Inhalation entry: deficient/ineffective mucociliary clearance, host response → bronchopulmonary disease ▫ Skin trauma entry: deficient keratinized skin barrier → local subcutaneous infection; deficient keratinized cornea → ocular infection ▪ Rapid filamentous growth → ↓ phagocytic clearing ▫ Phagocytosed → ↓ lysosomal destruction (phagocyte-lysosome fusion inhibition; catalase, dismutase production → ↓ reactive oxygen species → pathogen survival) TYPES Pneumonia ▪ Nocardia asteroides (common pathogen) ▪ > 2⁄3 of total disease ▪ Progression ▫ Empyema, pericardial effusion Primary cutaneous infections ▪ Nocardia brasiliensis (common pathogen) ▪ Cellulitis, ulcers, pyoderma, myocetma OSMOSIS.ORG 385

▪ Progression ▫ Abscess/nodular development, lymphangitis RISK FACTORS ▪ ↓ mucociliary clearance ▫ Cystic fibrosis, asthma, bronchiectasis ▪ Immunosuppression ▫ Iatrogenic (most commonly corticosteroid use); lymphoreticular malignancy; chronic obstructive pulmonary disease; chronic granulomatous disease; dysgammaglobulinemia; HIV infection; bone marrow, organ transplant COMPLICATIONS ▪ Organ dissemination ▫ Pulmonary infection → hematogenous spread (commonly) ▫ Most common: central nervous system (meningitis, cerebral abscess) ▪ Pulmonary ▫ Empyema, pericardial effusion ▪ Cutaneous ▫ Lymphangitis ▪ Ocular ▫ Endophthalmitis (ocular infection) SIGNS & SYMPTOMS Pneumonia ▪ Acute, subacute, chronic suppurative course ▫ Symptoms may also relapse/remit ▪ Cough, dyspnea common ▫ Anorexia, weight-loss (uncommon) ▫ Hemoptysis (cavitary disease) ▪ Rhonchi (crackles) ▪ ↓ breath sounds, tactile fremitus, +/egophony Local cutaneous infection ▪ Local erythema, warmth, +/- ulceration, nodular growth Neurologic infection ▪ Meningismus, fever, rigors, seizure 386 OSMOSIS.ORG DIAGNOSIS DIAGNOSTIC IMAGING Chest X-ray ▪ Pulmonary ▫ Homogeneous, non-segmental, cavitary alveolar infiltrate Brain MRI ▪ Neurologic ▫ ↑ T1 imaging intensity → ↑ enhancement (gadolinium) LAB RESULTS ▪ Tissue biopsy: histology (acid fast stain) ▫ Gram ⊕, branching, beaded filamentous growth TREATMENT MEDICATIONS Antibiotic monotherapy ▪ Mild/moderate disease ▪ 3–6 months treatment duration ▪ Sulfonamides → trimethoprimsulfamethoxazole (TMP-SMX) ▪ Linezolid ▫ Nocardia 100% sensitive ▫ Limited treatment duration (2–3 weeks) → ineffective monotherapy for complete therapy duration Antibiotic multi-agent therapy ▪ Severe disease ▪ Up to 6–12 months treatment duration ▪ Agents ▫ TMP-SMX + amikacin/carbapenem/ linezolid ▪ Commonly for progressive disease in immunosuppressed individuals/pulmonary, disseminated disease Prevention & vaccine ▪ Daily, full-strength TMP-SMX → secondary prophylaxis ▪ P. jirovecii TMP-SMX prophylaxis (3x/week) → ineffective

Chapter 71 Filaments SURGERY ▪ Indicated for ▫ Antibiotic-resistant, large cutaneous/ cerebral abscess (craniotomy/aspiration effective) ▫ Empyemas, large fluid collections ▫ Pulmonary nocardiosis → pericarditis (fatal if not performed) OSMOSIS.ORG 387