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Mycobacterium chimaera sp. nov. Enrico Tortoli Regional Reference Center for Mycobacteria Florence - Italy. presented at 24° Congress of ESM – Tartu, July 2, 2003. M. avium complex. M. avium M. avium subsp. avium M. avium subsp. silvaticum M. avium subsp. paratuberculosis
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Mycobacterium chimaera sp. nov. Enrico Tortoli Regional Reference Center for Mycobacteria Florence - Italy presented at 24° Congress of ESM – Tartu, July 2, 2003
M. avium complex • M. avium • M. avium subsp. avium • M. avium subsp. silvaticum • M. avium subsp. paratuberculosis • M. avium subsp. hominissuis • M. intracellulare • mycobacteria other than avium and intracellulare
Strains and patients • Isolated from 12 independent patients in 4 years • 11 out of 12 isolated from respiratory specimens • multiple isolate in 6 cases, single isolate in 6 cases • strains clinically non significant: 5 • strains clinically significant: 7 • immunocompetent patients (4 M and 3 F), 56-82 year old • pulmonary cavitations and emoptysis; pulmonary abscess; chronic obstructive pulmonary disease; bronchiectasis • dead: 1; treated: 6, recovered: 3
Conventional tests • Slow growth at 25-37°C • Colonies unpigmented or slightly yellow pigmented • Negative tests: • niacin; nitrate reduction; β-glucosidase; Tween 80 hydrolysis; 3-day arylsulfatase; urease; semiquantitative catalase; NaCltolerance; MacConkey growth • Positive tests: • 68°C catalase; tiacetazone and isoniazid tolerance
Lipid analysis • TLC • α-, keto- and wax ester-mycolates • GLC • best resemblance: M. intracellulare (50% similarity) • HPLC • two clusters of peaks
HPLC pattern M. avium M. intracellulare ???
DNA probe • Accuprobe • Positive: MAC, M. intracellulare • Negative: M. avium • INNO LiPA v.1 • Positive: Mycobacterium genus, MAIS • Negative: M. avium, M. intracellulare, M. scrofulaceum • INNO LiPA v. 2 • Positive: Mycobacterium genus, MAIS, M. intracellulare 2 • Negative: M. avium, M. intracellulare 1, M. scrofulaceum
Genetic sequencing • 16S rRNA • One nucleotide mismatch with M. intracellulare (GenBank) • Full match with M. intracellulare sequevar v (RIDOM) • ITS • Full match with MAC-A
Insertion elements • IS900: absent • IS901: absent • IS1245: absent
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MIN-A MIN-D MIN-B MIN-C Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MAC-E MAC-F MAC-H MAC-L MAC-R MAC-Q MAC-S MAC-T MAC-U MAC-N MAC-O MAC-I MAC-L* MAC-M MIN-A MIN-D MIN-B MIN-C Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MAC-E MAC-F MAC-H MAC-L MAC-R MAC-Q MAC-S MAC-T MAC-U MAC-N MAC-O MAC-I MAC-L* MAC-M MAC-B MAC-C MAC-K MIN-A MIN-D MIN-B MIN-C Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MAC-E MAC-F MAC-H MAC-L MAC-R MAC-Q MAC-S MAC-T MAC-U MAC-N MAC-O MAC-I MAC-L* MAC-M MAC-B MAC-C MAC-K MIN-A MIN-D MIN-B MIN-C MAC-D MAC-J* Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MAC-P MAC-E MAC-F MAC-H MAC-L MAC-R MAC-Q MAC-S MAC-T MAC-U MAC-N MAC-O MAC-I MAC-L* MAC-M MAC-B MAC-C MAC-K MIN-A MIN-D MIN-B MIN-C MAC-J MAC-D MAC-J* MAC-K* Philogeny
MAV-A MAV-C MAV-D MAV-G MAV-B MAV-E MAV-F MAC-P MAC-E MAC-F MAC-H MAC-L MAC-R MAC-Q MAC-S MAC-T MAC-U MAC-N MAC-O MAC-I MAC-L* MAC-M MAC-B MAC-C MAC-K MIN-A MIN-D MIN-B MIN-C MAC-J MAC-D MAC-J* MAC-K* Philogeny MAC-A
The 16S-ITS region variations • M. avium includes sequevars differing for up to 4 bases • M. intracellulare includes sequevars differing for up to 7 bases • Our strains differs • from M. avium for at least 20 bases • from M. intracellulare for at least 21 bases • from any other MAC for at least 15 bases • Unique markers to our strains • ITS position 149: adenosine replaced by thymidine • ITS position 234: guanosine replaced by adenosine • ITS position 230:one nucleotide deletion
Antimicrobial pattern • Resistance to ethambutol • Variable susceptibility to other drugs • Four strains present very low MICs to almost all drugs
M. chimaera sp. nov. • Accuprobe: M. intracellulare; LiPA 1: MAIS (non M.avium non M. intracellulare); LiPA 2: M. intracellulare 2 • Two-clustered HPLC profile • Unique genetic sequence in the 16S-ITS trait and unique phylogenetic position • Resistance to ethambutol • Isolated from the respiratory tract of immunocompetent, elderly patients with various pulmonary disorders; never isolated from the environment or from animals • High rate of clinical significance
Collaborations Regional Reference Center for Mycobacteria, Careggi Hospital, Florence Alessandro Mariottini, Gianna Mazzarelli Department of Experimental Pathology, University of Pisa, Pisa Carlo Garzelli, Nicoletta Lari, Laura Rindi Microbiology and Virology Laboratory, S. Camillo-Forlanini Hospitals, Rome Patrizia Chiaradonna Department of Public Health, University of Florence, Florence Rosanna Dei German Collection of Microorganisms and Cell Cultures, Braunschweig Reiner Kroppenstedt Regional Reference Center for Mycobacteria, S. Bortolo Hospital, Vicenza Paola Piccoli, Claudio Scarparo