Clinical significance, biochemical features, and susceptibility patterns of sporadic isolates of the Mycobacterium chelonae-like organism.
Mycobacterium chelonae-like organisms are nonpigmented rapidly growing mycobacteria whose clinical significance is unknown. We evaluated 87 sporadic isolates encountered in a clinical laboratory. Most isolates (62%) were respiratory; only 2 of 54 (4%) (both from patients with AIDS) were clinically significant. Among 33 nonrespiratory isolates, 20 of 33 (or 61%) were clinically significant. Clinical diseases included posttraumatic wound infections and catheter-related sepsis. Routine biochemical features included growth inhibition by 5% NaCl (100%), a smooth colony morphology (94%), positive 3-day arylsulfatase reaction (84%), no color or a light tan color on iron uptake (100%), and variable nitrate reduction (45%). Additional characteristics that helped to separate this group from M. chelonae and Mycobacterium abscessus were susceptibility to cephalothin (90%) and ciprofloxacin (100%), utilization of mannitol (94%) and citrate (83%) as carbon sources, and unique patterns of mycolic acid esters by high-performance liquid chromatography. This group was quite drug susceptible, with 100% of isolates inhibited by amikacin, imipenem, cefoxitin, cefmetazole, and the newer quinolones ciprofloxacin and ofloxacin. Three examples of this group, including a proposed type strain, have been deposited in the American Type Culture Collection.
Wallace
R J
RJ
Department of Microbiology, University of Texas Health Center, Tyler 75710.
Silcox
V A
VA
Tsukamura
M
M
Brown
B A
BA
Kilburn
J O
JO
Butler
W R
WR
Onyi
G
G
D001431:Bacteriological Techniques; D004352:Drug Resistance, Microbial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009165:Mycobacterium Infections, Nontuberculous / Q000382:microbiology; D016926:Mycobacterium chelonae / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D013045:Species Specificity; D009626:Terminology as Topic; D014871:Water Microbiology