In:
Antimicrobial Agents and Chemotherapy, American Society for Microbiology, Vol. 55, No. 2 ( 2011-02), p. 775-781
Abstract:
Clarithromycin was the drug of choice for Mycobacterium abscessus infections until inducible resistance due to erm (41) was described. Because M. abscessus was split into M. abscessus sensu stricto, Mycobacterium massiliense , and Mycobacterium bolletii , we looked for erm (41) in the three species and determined their clarithromycin susceptibility levels. Ninety strains were included: 87 clinical strains from cystic fibrosis patients (61%) and others (39%), representing 43 M. abscessus , 30 M. massiliense , and 14 M. bolletii strains identified on a molecular basis, and 3 reference strains. Clarithromycin and azithromycin MICs were determined by broth microdilution and Etest with a 14-day incubation period. Mutations in rrl (23S rRNA gene) known to confer acquired clarithromycin resistance were also sought. erm (41) was detected in all strains but with two deletions in all M. massiliense strains. These strains were indeed susceptible to clarithromycin (MIC 90 of 1 μg/ml) except for four strains with rrl mutations. M. abscessus strains harbored an intact erm (41) but had a T/C polymorphism at the 28th nucleotide: T28 strains (Trp10 codon) demonstrated inducible clarithromycin resistance (MIC 90 of 〉 16 μg/ml), while C28 strains (Arg10) were susceptible (MIC 90 of 2 μg/ml) except for two strains with rrl mutations. M. bolletii strains had erm (41) sequences similar to the sequence of the T28 M. abscessus group, associated with inducible clarithromycin resistance (MIC 90 of 〉 16 μg/ml). erm (41) sequences appeared species specific within the M. abscessus group and were fully concordant with clarithromycin susceptibility when erm (41) sequencing was associated with detection of rrl mutations. Clarithromycin-resistant strains, including the six rrl mutants, were more often isolated in cystic fibrosis patients, but this was not significantly associated with a previous treatment.
Type of Medium:
Online Resource
ISSN:
0066-4804
,
1098-6596
DOI:
10.1128/AAC.00861-10
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2011
detail.hit.zdb_id:
1496156-8
SSG:
12
SSG:
15,3
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