Nontuberculous Mycobacteria: Community and Nosocomial Waterborne Opportunistic Pathogens

The nontuberculous mycobacteria are opportunistic water- and soilborne pathogens that include over 150 species. Though slow growing, they are the hardiest of bacteria, able to grow in drinking water and resistant to disinfectants, antibiotics, and heat. They are natural inhabitants of drinking water distribution systems and plumbing in houses, hospitals, condominiums, and apartments, commonly known as premise plumbing. Thus, humans are surrounded and continually exposed. Nontuberculous mycobacteria cause pulmonary and dermal infections in adults, cervical lymphadenitis in young children, and bacteremia in immunocompromised individuals. The frequency of pulmonary infections is 10/100,000, with the highest rates in persons older than 60 years (100/100,000). In addition to community-acquired infections, hospital-acquired infections are becoming increasingly prevalent, usually associated with surgery or injection. Multiple mycobacterial species or clones are common in pulmonary patients, necessitating isolation of multiple mycobacterial-like colonies from patient samples, as isolates from a single patient may belong to different species with different antibiotic susceptibilities. The reemergence of nontuberculous mycobacterial disease following successful antibiotic therapy is common.