Virulence and drug susceptibility of Mycobacterium celatum.
The virulence and drug susceptibility of a clinical isolate of Mycobacterium celatum which showed smooth transparent (ST) and smooth opaque (SO) colonies were studied. While ST cells multiplied intracellularly and maintained their coccobacillary form in a human macrophage model of infection, SO cells formed long filaments and completely destroyed the phagocytes. In BALB/c mice, the ST variant, but not the SO variant, grew efficiently in the spleen, liver and lung. The ST variant was usually more resistant in vitro than the SO variant to drugs, with MIC values for clarithromycin (CLA), azithromycin (AZI), ciprofloxacin, sparfloxacin, amikacin, clofazimine, ethambutol and isoniazid being higher than those of the SO variant. In beige mice infected with the more highly virulent variant ST, CLA and AZI were the most active drugs in terms of viable count reduction in organs and mutant selection. Together, these observations indicate that the ST variant of M. celatum is a virulent form that can be efficiently inhibited in vivo by CLA and AZI.
Fattorini
Lanfranco
L
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Baldassarri
Lucilla
L
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Li
Yong-Jun
YJ
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Ammendolia
Maria Grazia
MG
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Fan
Yuming
Y
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Recchia
Simona
S
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Iona
Elisabetta
E
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
Orefici
Graziella
G
Laboratory of Bacteriology and Medical Mycology1 and Laboratory of Ultrastructures2, Istituto Superiore di Sanitá, Viale Regina Elena 299, 00161 Rome, Italy.
D000818:Animals; D004352:Drug Resistance, Microbial; D006801:Humans; D066298:In Vitro Techniques; D008264:Macrophages / Q000382:microbiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D009154:Mutation; D009161:Mycobacterium / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure; D009164:Mycobacterium Infections / Q000209:etiology / Q000382:microbiology; D014774:Virulence