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1、1Actinomyces & NocardiaActinomycetaceae Mycobacterium 分枝杆菌属分枝杆菌属Corynebacterium 棒状杆菌属棒状杆菌属Norcardia 诺卡氏菌属卡氏菌属Actinomyces 放放线菌属菌属Streptomyces 链霉菌属霉菌属Rhodococcus 红球菌属球菌属3Features of ActinomycetesGenus Morphology Acid-fastnessGrowth Source Disease Actinomyces Branching bacillinoneanaerobicOral, intesti
2、nal endogenous floraChronic cellulitis, draining sinusesNocardia Branching bacilli weakaerobicsoilPneumonia, skin pustules, brain abscessRhodococcus Cocci to bacilliVariable(weak)aerobicSoil, horsespneumoniaStreptomyces Branching bacilliNone Aerobic Soil Extremely rare?4ActinomycesSlow-growing, anae
3、robic; branching Gram-positive rodsIn pus tissues, sulfur granule is the most characteristic form(0.3mm)Most infections due to A israelii Bacteriology5Actinomycosis Flora throughout gastrointestinal tractEndogenous infection.Infection often involve mechanical disruption of the mucosa如拔牙如拔牙Sinus trac
4、t contain pus and sulfur granulesNo evidence of immunity.6andActinomycosis Chronic cellulitis, draining sinusesNocardiosis Pneumonia, skin pustules, brain abscess7Actinomycosis : ManifestationsActinomycosis exists in several forms Cervicofacial forms are most commonly seen, often linked to dental hy
5、giene Thoracic and abdominal actinomycosis are rare Chronic endometritis Surgery, trauma, and intrauterine devices provide opportunity.Cervicofacial Actinomycosis8Actinomycosis : Diagnosis Sinus drainage/pus contains few Actinomyces Drainage is often contaminated with other species Gram stains show
6、branching rods Anaerobic culture is required9Actinomycosis : Treatment Penicillin G Penicillin may have to be used empiricallyHigh dose, prolonged therapy Ampicillin , doxycycline, erythromycin, and clindamycin. 10Nocardia Bacteriology Beaded, branching Gram-positive rods ,weakly acid-fast Grow on c
7、ommon media in 2 to 3 days In contrast to Actinomyces, Nocardia species are strict aerobesAerial hyphae of NocardiaOrange colonies of Nocardia12Nocardiosis : Epidemiology Ubiquitous : primary source is soil ; Available in respiratory tract of healthy personsTransmitted by : Inhalation (pulmonary for
8、m ), Injection through trauma (cutaneous form )No case-to-case transmissionInfection in the immunocompromised is increased13Nocardiosis : Pathogenesis Able to survive in phagocytesPulmonary infection : N asteroids CNS dissemination: produces abscesses Minor trauma increases Cutaneous infectionsSkin
9、infections is usually related to N brasiliensis species 14Nocardiosis :Immunity Cell-mediated immunity : are dominant Macrophages:enhance capacity to kill Nocardia Patients with impaired cell-mediated immunity at higher risk for Nocardiosis 15Nocardiosis : Manifestations Bronchopneumonia : cough,dys
10、pnea, and fever Brain abscess Cutaneous syndrome: typically involves a pustule, fever, and tender lymphadenitis in the regional lymph nodes.16Nocardiosis : Diagnosis Gram stain is usually positiveOrganisms are present in greater numbers and distributed more evenly Weak acid fastness is characteristi
11、c: diagnostic for N asteroids or N brasiliensis Blood agar is sufficient for culture 17Nocardiosis : Treatment Sulfonamides Sulfonamides combined with trimethoprim Technique difficulties in sensitivity testing Resistant to penicillin, but some of the newer beta-lactams effective Antituberculous agen
12、ts and antifungal agents such as amphotericin B have no activity against Nocardia.18放线菌放线菌主要有放主要有放线菌属和菌属和诺卡氏菌属。卡氏菌属。放放线菌属菌属: :人体正常菌群，与牙周病、人体正常菌群，与牙周病、龋齿等口腔疾病有关。侵入等口腔疾病有关。侵入软组织可引起放可引起放线菌病。放菌病。放线菌引起的感染菌菌引起的感染菌为内源性感染内源性感染. . 表表现为软组织的化的化脓、多、多发性瘘管，性瘘管，脓液中可液中可见硫磺硫磺样颗粒粒， 是放是放线菌在菌在组织中形成的菌落。中形成的菌落。镜检硫磺硫磺样颗粒粒对疾病有疾病有诊断意断意义。诺卡氏菌属：卡氏菌属：腐生菌，引起免疫力低下或免疫抑制人群的腐生菌，引起免疫力低下或免疫抑制人群的诺卡氏病。卡氏病。为外源性感染，外源性感染，临床表床表现类型型为： 皮肤皮肤伤口感染口感染引起表皮、淋巴及皮下引起表皮、淋巴及皮下软组织感染。感染。 呼吸道吸入呼吸道吸入引起呼吸道及肺部化引起呼吸道及肺部化脓性感染；性感染；播散性感染播散性感染： 继发于于伤口感染和吸入感染，口感染和吸入感染， 可累及任何器官可累及任何器官
