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Actinomyces + nocardia
 

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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