| Mycobacterium tuberculosis | | Humans | Acid-fast bacilli Ziehl-Neelsen stain Auramine-rhodamine stain Gram neutral (do not stain well) Facultative intracellular Aerobic Löwenstein-Jensen agar Middlebrook medium Generation time: ∼12 hours [63] | Cord factor: arranges M. tuberculosis in a serpentine cord → ↑ TNF-α release and activation of macrophages → granuloma formation Surface glycolipids: (sulfatides) inhibit phagolysosomal fusion Infiltration of nonactivated macrophages → escape of humoral immune response Multi-drug resistance: mutation in KatG (catalase-peroxidase) → INH conversion to its active metabolite → INH resistance | Tuberculosis | | Isoniazid PLUS rifampicin PLUS ethambutol PLUS pyrazinamide See “Tuberculosis treatment.” |
| Mycobacterium leprae [64] | | Humans and armadillos | Acid-fast bacilli: Ziehl-Neelsen stain Obligate intracellular Generation time: up to 13 days [65] | Phenolic glycolipid I (PGL-1) Lipoarabinomannan | Leprosy | | Dapsone PLUS rifampicin (tuberculoid leprosy) Clofazimine (add in lepromatous leprosy) |
| Nontuberculous mycobacteria M. kansasii, M. ulcerans | M. avium-intracellulare | Ubiquitous | Acid-fast bacilli: Ziehl-Neelsen stain PCR Generation time: varies among the subtypes (faster than other mycobacteria) | M. avium-intracellulare are frequently multi-drug resistant | Mycobacterium avium complex infection: disseminated nontuberculous disease mainly in immunocompromised patients (e.g., HIV/AIDS) See “HIV-associated conditions.” | Soft tissue infections with draining sinuses (newly formed channels that lead from the focus of infection to the skin surface via a draining orifice) | Are more drug-resistant than M. tuberculosis Clarithromycin OR azithromycin PLUS rifabutin (OR rifampin) PLUS ethambutol |
| M. marinum | | | | Fish tank granuloma: skin infection usually of the hand that occur in individuals handling fish (e.g., aquarium handlers) | | |
| M. scrofulaceum | | | | Cervical lymphadenitis in children | | |
| Mycoplasma pneumoniae | | Humans are the only host | Microaerophile Incomplete/absent cell wall (not visible on gram stain) Bacterial membrane stabilized by cholesterol Pleomorphic Generation time: (1–3 weeks) [66] M. pneumoniae: grows on Eaton agar → “fried egg” appearance | Unresponsive to beta-lactam antibiotics due to lacking cell wall | Mycoplasma pneumonia (atypical pneumonia) Cold antibody hemolytic anemia (IgM) Erythema multiforme Acute interstitial nephritis Stevens-Johnson syndrome (affects mostly children and adolescents) | | Macrolides (e.g., erythromycin) OR doxycycline OR fluoroquinolones |
| Ureaplasma urealyticum | | Normal urogenital flora | | | Urocystitis | | Doxycycline OR macrolides (e.g., erythromycin) |
