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Actinomyces + nocardia
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Actinomyces + nocardia Actinomyces + nocardia Presentation Transcript

  • Actinomyces and Nocardia Dr Kamran Afzal Asst Prof Microbiology
  • Clinically important Gram positive bacilli
    • Bacilli with branching filaments
    • 1. Actinomyces
    • 2. Nocardia
    • Spore forming
    • 1. Bacillus
    • 2. Clostridium
    • Non-spore forming
    • 1. Corynebacterium
    • 2. Listeria
    • 3. Lactobacillus
  • Gram Positive Filamentous Bacteria no YES aerobe Streptomyces PARTIALLY sometimes aerobe Nocardia no YES ANAEROBE Actinomyces yes no aerobe Mycobacteria ACID FAST GRANULE OXYGEN GENUS
  • Actinomycetes
  • Actinomycetes
    • Genera Actinomyces and Nocardia are Gram positive non-motile and branching filamentous bacteria
      • Actinomyces is responsible for diseases of the oral cavity and intestines
      • Nocardia causes pulmonary disease
  • Actinomyces
    • “ Mykes” – Greek for “fungus”
    • Thought by early microbiologists to be fungus
    • Non-spore forming anaerobic or facultative anaerobic gram-positive bacteria
    • Normally found in mouth, throat and GIT of humans
    • “ Opportunistic Pathogens”
    • Those causing disease do not exist freely in nature
  • Actinomyces
    • Actinomyces
      • A. israelii – the commonest
      • A. meyeri
      • A. naeslundii
      • A. odontolyticus
      • A. viscosus
    • Actinomyces species: 30; 8: human disease
    • Filamentous, branching, Gram-positive, pleomorphic, non-spore forming, non acid fast, anaerobic or microaerophilic bacilli
  • Epidemiology
    • Geography/Season
      • Word wide
      • No seasonal variation
    • Habitat
      • Mouth, intestine and female genital tract
    • Who is at risk
      • Poor oral hygiene
      • Oral/dental surgery
      • Trauma patients
      • Women with IUDs
    • Transmission
      • From endogenous site to a sterile site
  • Actinomycosis
    • Non-contagious chronic infection characterized by multiple abscesses with granuloma formation, tissue destruction and open draining sinuses
      • Cervico-facial - commonest
      • Thoracic
      • Abdominal
      • Pelvic
      • Central nervous system
    • Contiguous; does not respect tissue planes
  • Pathogenesis
    • Not highly virulent (Opportunist)
      • Component of Oral Flora
        • Periodontal pockets
        • Dental plaque
        • Tonsillar crypts
      • Takes advantage of injury to penetrate mucosal barriers
        • Coincident infection
        • Trauma
        • Surgery
  • Pathogenesis
    • Source of infection: Endogenous
    • After local trauma, organisms invade tissues
    • Due to low oxygen tension, organisms multiply
    • Form hard yellow granules (sulfur granules) which are bacterial filaments solidified with tissue exudates
    • These granules drain outside through sinuses
  • Actinomycosis
    • Formation of indurated masses with fibrous walls and central loculations with pus
      • Pus contains "Sulfur Granules"
        • Gritty, yellow white
        • Average diameter 2mm
        • Composed of “mycelial” mass
    • Chronic infection
      • Formation of burrowing sinus tracts to skin or mucus membranes
        • Discharge purulent material
  • Cervico-facial Actinomycosis
    • Sinus tract originating in oral cavity has made its way to the surface at the jawline - “lumpy jaw”
    • Multiple sinuses, scarring on neck and submaxillary area
    • Contiguous spread to bone, neck, tongue etc
    • DDX: TB, fungi, nocardia, abscess, neoplasm
  • Actinomycosis
    • Involving chest Mycetoma foot
  • Lab Diagnosis
    • Specimens – open biopsy, aspiration material containing Sulphur granules (yellowish mycelial masses)
  • Lab Diagnosis
    • Prompt transport to lab oratory preferably in anaerobic device
    • The discharge should be mixed with sterile saline and allowed to stand, particles will separate out
    • Place between 2 slides and crush
      • Gram stain
      • Fluorescence stain
    • Histopathology of tissue
  • Sulfur Granule from Sinus Tract of Actinomycotic Infection The delicate filamentous bacilli (arrow) at the peripher y of crushed granule
  • Laboratory Diagnosis
    • Culture
      • BHI, BA, Thioglycolate broth
      • Aerobic Anaerobic
      • 37 0 C 37 0 C
    Slow growth on blood agar in 4-7 days Molar tooth colony
  • Histopathology
  • Actinomyces Identification Scheme
  • Treatment and Prophylaxis
    • Surgical debridement
    • Prolonged antibiotics (3-6 months)
      • Penicillin
      • Amoxicillin
      • Tetracycline
      • Erythromycin
      • Clindamycin
    • Maintenance of good oral hygiene
    • Antibiotic prophylaxis while mouth or GI tract is penetrated
  • Nocardia
  • Nocardia
    • 30 species, 13 of which cause human infection
    • N. asteroides, N. brasiliensis
    • Branching filament < 1 µ m
    • Fragmentation rod, coccoid form
    • Gram-positive beaded form
    • C ell wall; mycolic acid
    • Modified acid fast (1% H 2 S O 4 ) Partially acid fast
  • Epidemiology
    • Nocardia is everywhere in the environment
      • soil, organic matter, and water
    • Human infection
      • trauma and direct inoculation of the skin or soft tissues
      • by inhalation
    • Outbreaks
      • in oncology and transplant wards from HCWs hands
      • hospital construction with resultant contaminated dust
  • Risk Factors
    • Immunocompromised patients
      • 60% in pre-existing immune dysfunction
      • Organ transplantation, hematologic malignancy, alcoholism, steroid use, diabetes, AIDS
      • Patients with chronic pulmonary disorders, especially pulmonary alveolar proteinosis
  • Nocardiosis
    • An acute, subacute, and chronic infection of the skin or pulmonary tract
    • Transmitted through skin or pulmonary tract
    • Primary, post-traumatic or post-inoculation lung disease
    • Formation of abscesses which can metastasize
  • Pathology
    • Suppurative granulomata
    • Progressive fibrosis and necrosis
    • Sinus formation and destruction of adjacent structures
    • Macroscopically visible infective granules
    • Mimics fungal mycetoma and actinomycetomata
  • Clinical Syndromes
    • Mucocutaneous
      • Can occur after minor trauma and animal or insect bites; may also colonize open wounds
    • Cutaneous
    • Mycetoma Foot
      • A chronic progressive, destructive disease, occurring days to months after inoculation located distally on the limbs (foot)
      • Skin abscesses or cellulitis
      • Lymphocutaneous infections
    • Pulmonary
      • most common presentation
      • usually indolent and progressive
      • spread to contiguous structures, especially with soft tissue swellings or external fistulas
    • Clinical Presentations
      • pneumonia (often progressive in HIV) it can invade through surrounding tissues like actinomycosis
      • lung abscess
      • cavitary disease
      • empyema
    • CNS
      • in 44% of cases of systemic nocardiosis
      • classic signs and symptoms of pyogenic infections absent
      • indolent presentations lead to a diagnosis of a brain tumour
    • Other systems
      • Eye: can be hematogenous or due to eye trauma
      • Disseminated infections from central lines
  • Pulmonary Nocardiosis
  • Nocardia N ocardiosis ?? Specimen s : Sputum, pus, tissue biopsy Gram’s stain Modified acid-fast P artially acid fast Gram + ve, branching filament, fragmentation Culture and identification
  • Laboratory Diagnosis
    • Culture
    • BHI, SDA, BA, Thayer-martin agar – “Strict aerobes”
    • - Folded, heaped - Nocardia brasiliensis
    • - White to pink, orange - SDA, 30 0 C, 9 days
    • Identification
    • Biochemical tests
      • Top right casein +
      • Bottom right starch +
      • Bottom left tyrosine +
      • Top left xanthine -
    • Lysozyme test
      • Right : resistant to lysozyme
      • Left : does not grow in the presence of lysozyme
    Nocardia ID Quad plate
  • Treatment
    • I&D depending on the location
    • Sulfas the mainstay of therapy, but susceptibilities vary
    • For severely ill patients, CNS disease or in immunosuppressed patients use two or more drugs
      • TMP/sulfa PLUS amikacin and a carbapenem OR third-generation cephalosporin
    • Oral alternatives
      • minocycline and amoxicillin/clavulanate
  • Duration of Treatment
    • Expect a clinical response in 3 - 10 days
    • Often 3 - 6 months total
    • Cutaneous disease usually is cured in a month or two
    • CNS disease is treated for a year
    • Relapses can occur up to a year after stopping therapy
  • Outcomes
    • Cure rates of almost 100% are found in patients with skin or soft tissue disease
    • 90% in pleuro-pulmonary disease
    • 30-50% in brain abscess
    • The longer the delay in diagnosis,
      • the more extensive the disease and,
      • the worse the outcome
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