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A method is presented for the decontamination, liquefaction, and concentration of sputum specimens that are in transport more than 24 h. The method is inexpensive, and culture results compare well with those obtained with the accepted N-acetyl-L-cysteine and sodium hydroxide method for the isolation of tubercle bacilli. The working solution, 1% cetylpyridinium chloride and 2% sodium chloride, is mixed in equal volumes with sputum before the specimens are shipped. Tubercle bacilli remained viable after 8 days of exposure to this solution. Only Lowenstein-Jensen medium was used because the cetylpyridinium chloride in the inoculum remains active on 7H10 or other agar base media and partially inhibits the growth of tubercle bacilli.

A new slowly growing nonphotochromogenic Mycobacterium species of clinical importance is described. The biochemical characteristics of this organism were similar to those of Mycobacterium xenopi and members of the Mycohcterium avium complex. However, none of the strains reacted with commercially available genetic probes for the M. avium complex. The strains were resistant to most antituberculosis drugs. Multilocus enzyme electrophoresis revealed two original electrophoretic types, which was suggestive of new species. The strains contained a-, keto-, and dicarboxylic mycolates, as determined by thin-layer chromatography. A mycolic acid analysis by high-performance liquid chromatography revealed a chromatographic pattern similar to that of M. xenopi, but distinct from the patterns of previously described Mycobacterium species. Hexadecanoic and tuberculostearic acids were identified as the major cell wall fatty acids by gas-liquid chromatographic analysis; hexacosanoic acid was the major mycolic acid cleavage product, and 2-eicosanol was the major alcohol. Unusual strains not considered typical of previously described Mycobacterium species were received from the Veterans Administration Laboratory, West Haven, Conn. These organisms were patient isolates obtained from diverse geographic locations in the United States. Subsequently, additional strains were collected and characterized at the Centers for Disease Control, and the results corroborated the results of a previous study performed with high-performance liquid chromatography (HPLC) which identified them as members of a new Mycobactenurn species (2). The isolation of these bacteria from clinical specimens may pose a problem since they are resistant in vitro to most of the commonly used antituberculosis drugs. The strains were extensively characterized and found to be unique. The new species is named Mycobacteriurn celatum. MATERIALS AND METHODSStrains of mycobacteria. The sources of the strains, their designations, and their geographic distribution are shown in Table 1.Growth temperatures, colonial and cellular features, and biochemical tests. Single-colony isolates of each strain were selected by using a magnification of x10 and tested for purity. After each separate colonial isolate was grown in Middlebrook-Cohn 7H9 liquid medium, agar plates containing Middlebrook-Cohn 7H10 medium (7H10 medium) were streaked, and the growth was examined visually for purity. In addition, individual colony isolates were examined by performing an HPLC analysis of mycolic acids to verify the unique chromatographic patterns (2). The growth of the strains was examined on Lliwenstein-Jensen (L-J) egg medium and 7H10 medium incubated at 27, 30, 33, 37, 42, and 45°C. Morphologic variation in colonies was determined by examining L-J medium cultures incubated at 37°C. Pigmen-* Corresponding author. tation and photoinduction of pigment production were determined on 7H10 agar incubated at 37°C. Cell morphology was determined by microscopic examination (magnification, ~1 , 0 0 0 ) of colon...

Between October 15 and November 18, 1985, 5 patients on a medical ward of the Albany VA Medical Center (Ward 8A) became colonized with Mycobacterium fortuitum. Because other patients in Ward 8A were at risk of developing disease with M. fortuitum, microbiologic surveillance to identify colonization in sputum was begun. By February 15, 1986, 30 colonized patients had been identified in this ward but none in another ward with a comparable patient population, which suggests a source unique to Ward 8A. Because water has been recognized as a source of opportunistic mycobacterial pathogens, we conducted a retrospective case-control study using a telephone survey questionnaire to examine a number of water exposures in 10 patients and 20 control subjects. Exposure to ice from the Ward 8A ice machine, but not to potable water, was associated with colonization with M. fortuitum. Large-volume water samples from a variety of sources were cultured for acid-fast bacilli. M. fortuitum was isolated only from the ice machine in Ward 8A. The ice machine was disconnected, and no additional patients became colonized. Although ice machines are infrequently implicated in nosocomial outbreaks, they represent a potential source for pathogens that survive or replicate in water.