Emerging Mycobacteria spp. in Cooling Towers

mydia sequanensis, a new intracellular Chlamydiales isolated from Seine river water using amoebal co-culture.lence of different Chlamydia-like organisms in an asymptomatic population. Clin Microbiol Infect. In press 2008. To the Editor: The importance of nontuberculous mycobacteria (NTM) in various clinical situations recently has increased. Members of the My-cobacterium avium complex (MAC) cause a high percentage of infections in persons with acquired immunode-fi ciency syndrome. Some species are considered emerging pathogens, particularly those of the M. chelonae–M. abscessus group. They occur not only in immunocompromised persons but also in persons without predispos-ing conditions. Although sources of infection are considered to originate from the human environment, until now cooling towers were not clearly demonstrated to be one of these contamination sources, despite being suspected (1). Natural streams, groundwater , brook waters, and swamps already were reported to contain different species of NTM. Constructed environments, such as hospital hot water systems, aerosols from showers, ice machines, swimming pools, dental unit water, endoscopes, and broncho-scopes are other sources (2). Other studies have shown members of MAC in drinking-water distribution systems (3). A 1999 study in South Africa reported the presence of mycobacteria in cooling towers but reported no details about species (4). In 2003, cooling towers were reported to be a potential source of slow-growing mycobacterial species (1). Some mycobacterial species recently were shown to survive within amebae (5). We aimed to study the population of ameba-associated mycobacterial species in 3 cooling towers using a co-coculture method. These cooling towers (E, H, and O), located in downtown Paris, France, were sampled in May 2006. Water was taken in a sample point of the cooling circuit located just before the entrance of the tower basins. Because these cooling towers are regularly treated by oxidizing biocide BCDMH (1-bromo-3-chloro-5, 5-dimethylhydantoin) to prevent development of Legionella spp., no Legionella spp. or Legionella-like amebal pathogens were isolated. Two liters of water samples were fi ltrated through 0.22-μm pore-sized fi lters that were injected onto amebal microplates as previously described (6) and incubated at 32°C. We screened amebal microplates by examination under inverted microscope and by Ziehl-Nielsen, Gram, and Gimenez staining. Positive wells were subcultured on ax-enic medium and incubated at 32°C for 10 days. Acid-fast isolates were identi-fi ed by using partial rpoB gene amplification and sequencing with Myco-F and Myco-R primers (7). These primers did not allow amplifi cation of partial rpoB gene for the 6 M. phocaicum …