Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 16, Number 9—September 2010

Determinants of Multidrug-Resistant Tuberculosis Clusters, California, USA, 2004–2007

John Z. MetcalfeComments to Author , Elizabeth Y. Kim, S.-Y. Grace Lin, Adithya Cattamanchi, Peter Oh, Jennifer Flood, Philip C. Hopewell, and Midori Kato-Maeda
Author affiliations: Author affiliations: University of California, San Francisco, California, USA (J.Z. Metcalfe, E.Y. Kim, A. Cattamanchi, P.C. Hopewell, M. Kato-Maeda); California Department of Public Health, Richmond, California, USA (S.-Y.G. Lin, P. Oh, J. Flood)

Main Article

Table 2

Isoniazid and rifampin resistance–conferring mutations among 121 clustered and nonclustered MDR TB infections, California, USA, 2004–2007*

Molecular basis for drug resistance Nonclustered, n = 96, no. (%) Clustered, n = 25, no. (%)
Isoniazid resistance
katG S315T mutation 66 (69) 25 (100)
Other katG mutation† 8 (8) 0
inhA promoter‡ 23 (26) 0
No katG S315T or inhA promoter mutation detected§
5 (5)
Rifampin resistance¶
rpoB codons 511–518 8 (9) 2 (8)
rpoB codons 523–529 25 (27) 4 (16)
rpoB codons 529–534 57 (62) 19 (76)
rpoB codons 515–521 2 (2) 0

*Two isolates with otherwise complete genotyping data were unavailable for molecular beacon analysis. MDR TB, multidrug-resistant tuberculosis; S315T, serine-to-threonine substitution at position 315.
†Novel mutations detected: Y413STOP, T314T (silent), W161G, D61E (Fur A), R145P, P325L, and V633F.
inhA promoter mutation was concomitant with 4/91 (4%) isolates harboring the katG S315T and 2/8 (25%) isolates with katG mutations other than S315T.
§No mutations detected by molecular beacons; sequencing was not possible for these isolates because of degraded DNA.
¶Rifampin resistance–conferring mutations were not detected by the molecular beacon assay for 4 isolates.

Main Article

Page created: August 28, 2011
Page updated: August 28, 2011
Page reviewed: August 28, 2011
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.