TY - JOUR
T1 - Genetic diversity of Mycobacterium avium isolates recovered from clinical samples and from the environment
T2 - Molecular characterization for diagnostic purposes
AU - Álvarez, Julio
AU - García, Ignacio Gómez
AU - Aranaz, Alicia
AU - Bezos, Javier
AU - Romero, Beatriz
AU - De Juan, Lucía
AU - Mateos, Ana
AU - Gómez-Mampaso, Enrique
AU - Domínguez, Lucas
PY - 2008/4
Y1 - 2008/4
N2 - Isolation of Mycobacterium avium complex (MAC) organisms from clinical samples may occur in patients without clinical disease, making the interpretation of results difficult. The clinical relevance of MAC isolates from different types of clinical samples (n = 47) from 39 patients in different sections of a hospital was assessed by comparison with environmental isolates (n = 17) from the hospital. Various methods for identification and typing (commercial probes, phenotypic characteristics, PCR for detection of IS1245 and IS901, sequencing of the hsp65 gene, and pulsed-fleld gel electrophoresis) were evaluated. The same strain was found in all the environmental isolates, 21 out of 23 (91.3%) of the isolates cultured from urine samples, and 5 out of 19 (26.3%) isolates from respiratory specimens. This strain did not cause disease in the patients. Testing best characterized the strain as M. avium subsp. hominissuis, with the unusual feature that 81.4% of these isolates lacked the IS1245 element. Contamination of certain clinical samples with an environmental strain was the most likely event; therefore, characterization of the environmental mycobacteria present in health care facilities should be performed to discard false-positive isolations in nonsterile samples, mainly urine samples. Molecular techniques applied in this study demonstrated their usefulness for this purpose.
AB - Isolation of Mycobacterium avium complex (MAC) organisms from clinical samples may occur in patients without clinical disease, making the interpretation of results difficult. The clinical relevance of MAC isolates from different types of clinical samples (n = 47) from 39 patients in different sections of a hospital was assessed by comparison with environmental isolates (n = 17) from the hospital. Various methods for identification and typing (commercial probes, phenotypic characteristics, PCR for detection of IS1245 and IS901, sequencing of the hsp65 gene, and pulsed-fleld gel electrophoresis) were evaluated. The same strain was found in all the environmental isolates, 21 out of 23 (91.3%) of the isolates cultured from urine samples, and 5 out of 19 (26.3%) isolates from respiratory specimens. This strain did not cause disease in the patients. Testing best characterized the strain as M. avium subsp. hominissuis, with the unusual feature that 81.4% of these isolates lacked the IS1245 element. Contamination of certain clinical samples with an environmental strain was the most likely event; therefore, characterization of the environmental mycobacteria present in health care facilities should be performed to discard false-positive isolations in nonsterile samples, mainly urine samples. Molecular techniques applied in this study demonstrated their usefulness for this purpose.
UR - http://www.scopus.com/inward/record.url?scp=42449156360&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=42449156360&partnerID=8YFLogxK
U2 - 10.1128/JCM.01621-07
DO - 10.1128/JCM.01621-07
M3 - Article
C2 - 18272714
AN - SCOPUS:42449156360
SN - 0095-1137
VL - 46
SP - 1246
EP - 1251
JO - Journal of clinical microbiology
JF - Journal of clinical microbiology
IS - 4
ER -