Pathogenic Actinomycetes and Infections

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What is the primary site of involvement in actinomycosis, and what introduces the endogenous bacteria into the mucosa?

The primary site of involvement is the mucosa, and it is introduced by trauma.

What are the three common forms of actinomycosis based on the site of involvement?

Cervicofacial, thoracic, and abdominal actinomycosis.

What is the optimal growth condition for most strains of A. israelii and other agents of actinomycosis?

An atmosphere with increased carbon dioxide.

What types of concomitant bacteria are often present in actinomycosis, in addition to the primary agent?

Fastidious gram-negative bacilli, staphylococci, streptococci, or enteric gram-negative bacilli. Signup and view all the answers

What is the characteristic feature of actinomycosis lesions?

Pyogenic lesions with interconnecting sinus tracts that contain granules composed of microcolonies of bacteria embedded in tissue elements. Signup and view all the answers

What is the significance of acid-fast staining in N. brasiliensis?

N. brasiliensis may be acid-fast. Signup and view all the answers

What methods are used to differentiate pathogenic actinomycetes, such as Actinomadura and Streptomyces species?

Biochemical tests and chromatographic analysis of cell wall components. Signup and view all the answers

What is the treatment approach for actinomycetoma, and when is therapy most effective?

Combinations of streptomycin, trimethoprim-sulfamethoxazole, and dapsone, with therapy most effective when begun early before extensive damage has occurred. Signup and view all the answers

What are the possible sources of abdominal actinomycosis?

ruptured appendix or an ulcer Signup and view all the answers

What is the rare occurrence of genital actinomycosis in women caused by?

colonization of an intrauterine device with subsequent invasion Signup and view all the answers

What are sulfur granules composed of?

tissue and bacterial filaments, which are club-shaped at the periphery Signup and view all the answers

What is the cultivation method for diagnosing actinomycosis?

specimens are cultured in thioglycolate broth and on brain-heart infusion blood agar plates, which are incubated anaerobically or under elevated carbon dioxide conditions Signup and view all the answers

What is the characteristic of the main agents of actinomycosis?

catalase-negative Signup and view all the answers

What is the effective treatment for actinomycosis?

prolonged administration (6–12 months) of a penicillin Signup and view all the answers

Why is surgical excision and drainage sometimes required in the treatment of actinomycosis?

because drugs may penetrate the abscesses poorly, and some of the tissue destruction may be irreversible Signup and view all the answers

Why are individuals with recurrent infections given prophylactic penicillin?

especially prior to dental procedures Signup and view all the answers

What is the primary mode of transmission of Nocardiosis?

Inhalation of Nocardia bacteria Signup and view all the answers

What is the characteristic morphology of Nocardia colonies on agar media?

Heaped, irregular, waxy colonies Signup and view all the answers

What is the composition of the cell wall of Nocardia bacteria?

Mycolic acids, which are shorter-chained than those of Mycobacteria Signup and view all the answers

What is the significance of partial acid-fastness in Nocardia bacteria?

It is a characteristic feature of Nocardia bacteria Signup and view all the answers

What is the primary method of identification of Nocardia species?

Morphology, Gram staining, and catalase testing Signup and view all the answers

What is the common presentation of Nocardiosis?

Subacute to chronic pulmonary infection Signup and view all the answers

What is the significance of urease production in Nocardia bacteria?

It is a diagnostic feature Signup and view all the answers

What is the characteristic of the aerial filaments formed by Nocardia bacteria?

They fragment after formation, breaking into coccobacillary cells Signup and view all the answers