Final Aggregate Report

Attachment M: Final Aggregate Report

Centers for Disease Control and Prevention
Model Performance Evaluation Program

Mycobacterium tuberculosis
and
Nontuberculous Mycobacteria Drug
Susceptibility Testing Program
Report of Results
for the Performance Evaluation Survey
Conducted During November 2011
UNITED STATES DEPARTMENT OF HEALTH AND HUMAN
SERVICES

Use of trade names and commercial sources is for identification only and
does not imply endorsement by the
Centers for Disease Control and Prevention, or
U.S. Department of Health and Human Services.

MTB NTM DST Report for November 2011 Samples Survey

Purpose

The purpose of this report is to present the results of the Centers for Disease Control and
Prevention (CDC) Model Performance Evaluation Program for Mycobacterium tuberculosis
and Nontuberculous Mycobacteria Drug Susceptibility Testing (MPEP MTB NTM DST)
survey sent to participants in November 2011.

The production of this report was coordinated within CDC by
Coordination of
report production

Toby Merlin, MD, Director, National Center for Emerging and Zoonotic Infectious Diseases
(NCEZID), Division of Preparedness & Emerging Infections (DPEI)
Mark Rayfield, PhD, Chief, NCEZID, DPEI, Laboratory Systems Development Branch
(LSDB)
Sharon Granade, MPH, MT(ASCP), Team Lead, NCEZID, DPEI, LSDB
Michael F. Iademarco, MD, MPH, Chief, National Center for HIV/AIDS, Viral Hepatitis,
STD, and TB Prevention (NCHHSTP), Division of Tuberculosis Elimination (DTBE),
Laboratory Branch (LB)
Beverly Metchock, DrPH, D(ABMM), Team Lead, Reference Laboratory, NCHHSTP, DTBE,
LB

The material in this report was developed and prepared by
Report content
MTB NTM DST MPEP………….Suzette Brown, MS, Health Scientist
Pawan Angra, MS, PhD, Associate Service Fellow
MTB NTM DST MPEP acknowledges the contribution of Jagdeep Bedi, CDC contractor
(Northrop Grumman); Ryan McCormick, CDC contractor (Northrop Grumman); CDC/Atlanta,
Lois Diem, CDC/Atlanta; Janice Hall-Dean, CDC/Atlanta; for their help in preparing this report.
Use of trade names and commercial sources is for identification only and does not imply
endorsement by the U.S. Department of Health and Human Services.

Contact
information

Comments and inquiries regarding this report should be directed to the Model Performance
Evaluation Program by calling (404) 718-4087 or (888) 465-6062.
You may also contact Ms. Sharon Granade: Telephone (404) 718-4509;
email sgranade@cdc.gov.

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Table of Contents
MTB NTM DST Report for November 2011 Samples Survey

2

Introduction: Analyses of the November 2011 M. tuberculosis and Nontuberculous Mycobacteria Drug
Susceptibility Test Results Reported by Participating Laboratories

4

Susceptibility Testing Results for the M. tuberculosis Isolates Panel Shipped November 7, 2011

5

Descriptive Information about Participant Laboratories

6

Primary Classification ................................................................................................................................................................ 6
Annual Number of M. tuberculosis Drug Susceptibility Tests Performed by Participants ........................................................ 7
Laboratory Susceptibility Testing Procedures Used by Participants ......................................................................................... 8
The Primary M. tuberculosis Susceptibility Testing Media Used by Participants ..................................................................... 9
Antituberculous Drugs Used by Participants ............................................................................................................................. 10
Tabulated data

12

Explanation of Tables 1 through 5

12

Isolate F, M. tuberculosis–resistant to Rifampin at 1.0µg/ml by Agar Proportion .................................................................... 13
Isolate G, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml and Streptomycin at 2.0µg/ml and 10.0µg/ml by
Agar Proportion ......................................................................................................................................................................... 16
Isolate H, M. tuberculosis–resistant to Streptomycin at 2.0µg/ml by AP method and Pyrazinamide at 100.0µg/ml by MGIT
method. ...................................................................................................................................................................................... 20
Isolate I, M. tuberculosis–susceptible to first-line and second-line drugs ................................................................................. 24
Isolate J, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml; Ethambutol at 5.0µg/ml; Amikacin at 4.0µg/ml;
Capreomycin at 10.0µg/ml; and Kanamycin at 5.0µg/ml by Agar Proportion 7H10 method ................................................... 27
Abbreviations Used in This Report

31

References

32

Table of Figures
Figure 1: Distribution of the Annual Volume of M. tuberculosis Isolates Tested for Drug Susceptibility by Participants
in the 2011 Calendar Year.................................................................................................................................................7
Figure 2: Susceptibility Testing Methods Reported by Participant Laboratories ............................................................... 8
Figure 3: Primary M. tuberculosis Susceptibility Test Medium Used by Participants ........................................................9
Figure 4: Antituberculous Drugs Used by Participants....................................................................................................... 11

Table of Tables
Table 1: Participant results for M. tuberculosis, Isolate F–resistant to Rifmapin at 1.0µg/ml by AP ............................. 14
Table 2: Participant results for M. tuberculosis Isolate G–resistant to INH at 0.2µg and 1.0µg /ml and Streptomycin at
2.0µg/ml and 10.0µg/ml by AP method .......................................................................................................................... 18
Table 3: Participant results for M. tuberculosis Isolate H–resistant to Streptomycin at 2.0µg/ml by AP method and
Pyrazinamide at 100.0µg/ml by MGIT method ............................................................................................................. 22
Table 4: Participant results for M. tuberculosis, Isolate I– susceptible to first-line and second-line drugs .................... 25
Table 5: Participant results for Isolate J, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml; Ethambutol
at 5.0µg/ml; Amikacin at 4.0µg/ml; Capreomycin at 10.0µg/ml; and Kanamycin at 5.0µg/ml by Agar Proportion
7H10 method .................................................................................................................................................................... 29

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Introduction: Analyses of the November 2011 M. tuberculosis and Nontuberculous
Mycobacteria Drug Susceptibility Test Results Reported by Participating
Laboratories
This report analyzes the laboratory demographic information and drug susceptibility testing results reported to the
Centers for Disease Control and Prevention (CDC) by participating laboratories for the panel of five
Mycobacterium tuberculosis Complex1 isolates shipped in November 2011. Panels were sent to 98 laboratories
and all laboratories participated in evaluation of the panels.

Laboratories performed testing by using Agar Proportion 7H10 (AP 7H10); Agar Proportion 7H11 (AP 7H11)
collectively called Agar Proportion methods (AP) when not mentioned individually; BACTECTM 460 TB
(BACTECTM); BACTECTM MGITTM 960 (MGITTM); VersaTREK® and molecular methods consist of Genotype
MTBDRsl; Genotype MTBDRplus; Xpert MTB/RIF; and Laboratory Developed Tests.

This aggregate report is prepared in a format that will allow laboratories to compare their results with those
obtained by other participants for the same strains using the same method, drug, and drug concentrations. We
encourage circulation of this report to personnel who are involved with drug susceptibility testing, reporting, or
interpreting for M. tuberculosis isolates.

CDC is neither recommending nor endorsing testing practices reported by participants. For approved standards,
participants should refer to consensus documents published by the Clinical and Laboratory Standards Institute
(CLSI), “Susceptibility Testing of Mycobacteria, Nocardiae, and Other Aerobic Actinomycetes; Approved
Standard-Second Edition,” M24-A2 (ISBN 1-56238-746-4).[1]

1

Historically, the intent of the exercise was to assess performance using organism that were of Mycobacterium tuberculosis
Complex and were non-tuberculous mycobacteria. Overtime, non-tuberculous mycobacteria have been dropped. Although it
is possible that any of the eight species of Mycobacterium tuberculosis Complex could be present in the isolates selected,
identification is not part of the panel selection nor the exercise and it is presumed M. tuberculosis is the dominant species
represented. For these reasons and simplicity, we refer to M. tuberculosis throughout the report.
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Susceptibility Testing Results for the M. tuberculosis Isolates Panel Shipped
November 7, 2011
The table below provides the intended results of the panel shipment that was sent to participants in November
2011. Although CDC recommends broth-based methods for routine M. tuberculosis complex drug susceptibility
testing, this table provides the results obtained by the reference agar proportion method, except in the case of
pyrazinamide, where BACTEC™ was the testing method.

Isolate

Susceptibility Testing Results

F

Resistant to Rifampin (RIF)

G

Resistant to Isoniazid (INH)
Resistant to Streptomycin (SM)

H

Resistant to Streptomycin (SM)
Resistant to Pyrazinamide (PZA)

I

Susceptible to first-and second-line drugs

J

Resistant to Isoniazid (INH)
Resistant to Ethambutol (EMB)
Resistant to Kanamycin (KM)
Resistant to Capreomycin (CAP)
Resistant to Amikacin (AMK)

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Descriptive Information about Participant Laboratories
Primary Classification
This report contains the drug susceptibility testing results submitted to CDC by 98 laboratories in 41 states and
Puerto Rico.

The participants were asked to indicate the primary classification of their laboratory.
MPEP participants self-classified as
62 (63.3%): Health Department (city, county, state, regional, district, or national reference laboratory);
25 (25.5%): Hospital [city, county, district, community, state, regional, military, Veterans
Administration, Federal government (other than military), privately-owned, university, HMO/PPO*owned and operated, or religious-associated];
9 (9.2%): Independent [e.g., commercial, commercial manufacturer of reagents, HMO satellite clinic,
reference laboratory (non-government affiliated)]; and
2 (2.0%): Other [Federal government research (nonmilitary)];

* HMO: health maintenance organization; PPO: preferred provider organization

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Annual Number of M. tuberculosis Drug Susceptibility Tests Performed by Participants
Figure 1 shows the number of drug susceptibility tests performed on M. tuberculosis isolates by the 98
participants in one calendar year, January 1–December 31, 2010, excluding quality control isolates. The counts
range from four to 1,500. Seventeen (17) laboratories reported performing less than 21 drug susceptibility tests
per year. To ensure testing proficiency, laboratories with low volumes are encouraged to consider referral of M.
tuberculosis drug susceptibility testing.

Figure 1: Distribution of the Annual Volume of M. tuberculosis Isolates Tested for Drug Susceptibility by
Participants in the 2011 Calendar Year

25

Number of Laboratories Responding

22
20

n=98

16
15
15

14

10

8
7
6

5

5

4
1

0

Number of Isolates Tested per Year

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Laboratory Susceptibility Testing Procedures Used by Participants
Participants were asked to report all M. tuberculosis susceptibility testing methods that were used to test these
isolates. Sixty-two laboratories used only one method for testing, whereas 31 laboratories used two methods, four
laboratories used three methods, and one laboratory used four methods. Figure 2 shows the reported susceptibility
methods.

Figure 2: Susceptibility Testing Methods Reported by Participant Laboratories
80
71
Number of Laboratories Responding

70
60
n= 140

50
40
28

30

25

20
8

10

4

4

0
MGIT*

Agar
Proportion
7H10†

Radiometric‡ VersaTREK§

Agar
Proportion
7H11†

Molecular
Methods#

Susceptibility Testing Methods

MGIT™ Mycobacteria Growth Indicator Tube
Agar Proportion using Middlebrook mediums 7H10 or 7H11
‡
Radiometric is BACTEC™ 460 TB
§
VersaTREK® Myco Susceptibility Kit
#
Molecular methods include: Laboratory Developed Tests (4), Genotype MTBDRsl (1), Genotype MTBDRplus (1),
Xpert MTB/RIF (2) methods
*
†

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The Primary M. tuberculosis Susceptibility Testing Media Used by Participants
Participants were asked to indicate the primary M. tuberculosis susceptibility test medium used by their
laboratory for the isolates in the November 2011 shipment. Instructions were to select only one method as their
primary method. Figure 3 shows the responses submitted by the 98 participants.

Figure 3: Primary M. tuberculosis Susceptibility Test Medium Used by Participants

80

Number of Laboratories Reporting Results

70

n=98

69

60

50

40

30

18

20

6

10

3

2

0
MGIT System

Radiometric
(BACTEC 460)

Middlebrook 7H10 VersaTREK Myco Middlebrook 7H11

Primary Medium for MTBC Susceptibility Testing

Of the 71 laboratories that reported using MGIT™ as one of their methods for testing the MTB NTM DST
isolates,
69 indicated that the MGIT™ method was their primary method for susceptibility testing; and
2 laboratories indicated Agar proportion (AP) was their primary method using AP 7H10.

Of the 28 laboratories who reported using AP 7H10 as a method for testing the isolates,
6 used this as their primary method; however, two laboratories did not report AP 7H10 as one of their
testing methods in this challenge;
19 used MGIT™ as their primary method; and
5 used BACTEC™ as their primary method.
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Of the 25 laboratories who reported using BACTEC™ 460TB as one of their methods for testing the isolates,
18 used this as their primary method;
4 used MGIT™ as their primary method;
2 laboratory indicated AP was their primary method using AP 7H11; and
1 laboratory indicated AP was their primary method using AP 7H10.
Of the 4 laboratories who reported using VersaTREK® indicated as a method for testing the isolates.
3 laboratory indicated this as their primary method; and
1 laboratory indicated AP was their primary method using AP 7H10.

Of the 4 laboratories who reported using AP 7H11 as a method for testing the isolates,
2 used this as their primary method;
1 used MGIT™ as their primary method; and
1 used BACTEC™ as their primary method.

Antituberculous Drugs Used by Participants
CLSI recommends a full panel of first-line (primary) drugs (isoniazid [INH], rifampin [RMP], ethambutol [EMB],
and pyrazinamide [PZA])[1], because it represents a combination of tests that provides the clinician with
comprehensive information related to the four-drug therapy currently recommended for treatment of most patients
in the United States with tuberculosis. All participants reported results for three of the first-line drugs—INH,
RMP, and EMB; 86 (87.8%) of the participants also reported results for PZA.

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Figure 4 shows the number of laboratories testing each drug. The number at the right of each bar represents the
number of laboratories that tested the drug.
Figure 4: Antituberculous Drugs Used by Participants
Amikacin (AMK)
Azithromycin (AZM)
Capreomycin (CM)
Ciprofloxacin (CIP)
Clarithromycin
Clofazimine (CLF)
Cycloserine (CS)
Ethambutol (EMB)
Ethionamide (ETH)
Gatifloxacin
Isoniazid (INH)
Kanamycin (KM)
Levofloxacin (LEV)
Moxifloxacin (MOX)
Ofloxacin (OFX)
p-Aminosalicyclic Acid (PAS)
Pyrazinamide (PZA)
Rifabutin (RBT)
Rifampin (RMP)
Streptomycin (SM)

14
1

N=98

Drugs Tested by Participant Laboratories

25
10
1
2
11

98
31
1
98
23
3
4
23
20
86
14
98
78
0

10

20

30

40
50
60
70
Number of Laboratories

80

90

100

Note: Providing test results for all drugs that are reported to CDC by participants should not be construed as a
recommendation or endorsement for testing particular drugs or drug concentrations with M. tuberculosis isolated
from patients. It is assumed that some of the drugs are being tested for research purposes or potential use in the
few referral institutions that may treat patients with M. tuberculosis isolates resistant to almost all standard drugs.
According to CLSI, “Second-line drugs may be tested simultaneously if mutations associated with INH and RMP
resistance have been detected by molecular assays, or if epidemiological situations support the practice and
resources are available. Second-line drugs, both traditional and newer agents, should be tested for isolates
resistant to RMP or any two of the primary drugs. Isolates with mono-resistance to the critical concentration of
INH also should be tested for susceptibility to second-line agents if the clinician is planning to include a
fluoroquinolone in the treatment regimen. Laboratories should not add drugs to their testing panel without
consulting physicians with expertise in treating multidrug-resistant tuberculosis. Laboratories may contact their
local tuberculosis control program for referrals to physician experts in the treatment and care of tuberculosis”.

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Tabulated data
This section provides the complete set of data in tabulated format for the M .tuberculosis isolates F, G, H. I, and J
sent in the November 2011 shipment. The following information/explanation pertains to all the tables.

Explanation of Tables 1 through 5
In the following tables, the shaded rows indicate critical concentrations for each test method. For each
drug, the critical concentration is defined as the lowest concentration that inhibits 95% of “wild-type”
strains of M. tuberculosis organisms that have not been exposed to the drug; but that simultaneously does
not inhibit strains of the M. tuberculosis considered resistant that are isolated from patients who are not
responding to therapy.[1]

The test results (S represents susceptible and R represents resistant) are listed in the appropriate columns
along with a corresponding total number of tests (Sum column) to provide a denominator for determining
the level of consensus. This report contains all results reported by participating laboratories, including
many drug concentrations with only one result.
Participants should note that the CLSI approved standard “Susceptibility Testing of Mycobacteria,
Nocardiae, and Other Aerobic Actinomycetes,” M24-A2 (ISBN 1-56238-746-4) CLSI, 940 West Valley
Road, Suite 1400, Wayne, Pennsylvania 19087-1898, USA, 2011 recommends testing streptomycin as a
second line drug and also adds ofloxacin and rifabutin to the list of recommended secondary drugs. For a
complete list of drugs to be tested, consult the CLSI document M24-A2.[1]

Concentrations are listed in micrograms per milliliter (µg/ml).
A concentration of 0.00 is entered for results associated with genetic testing [Hain GenoType®
MTBDRplus Assay or Hain GenoType® MTBDRsl Kit (HAIN Lifescience, Germany); Xpert
MTB/RIF(Cepheid) ; and Laboratory Developed Tests] for which no drug concentration is required.

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Isolate F, M. tuberculosis–resistant to Rifampin at 1.0µg/ml by Agar Proportion
Rifampin (RMP) is a first-line drug for treatment of all forms of tuberculosis caused by organisms known or
presumed to be susceptible to this drug. It is bactericidal for M. tuberculosis at the critical concentration of
1.0μg/ml for AP (on Middlebrook 7H10 and 7H11 agars) and equivalent critical concentrations for
BACTEC460™, MGIT960™, and VersaTREK® of 2.0μg/ml, 1.0μg/ml, and 1.0μg/ml, respectively. The mechanism
of action of RMP is to inhibit mycobacterial transcription by targeting DNA-dependent RNA polymerase[2].
More than 96% of RMP-resistant isolates contain a mutation in the 81-base pair (bp) central region of the rpoB
gene that encodes the β-subunit of the bacterial DNA-dependent RNA polymerase[2]. The activity of RMP in
RMP-resistant isolates depends on both the mutation position and the type of amino acid change in the rpoB gene.
Mutations in codons 531, 526, and 516 are among the most frequent mutations in RMP-resistant isolates and
serve as predictors of RMP resistance. DNA sequence analysis of rpoB of Isolate F revealed a C>T point mutation
in the rpoB locus resulting in histidine being replaced by tyrosine at codon 526 (His526Tyr).
Ninety-eight laboratories reported RMP results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
100% (27/27) of the laboratories reporting AP results;
100% (18/18) of the laboratories reporting BACTEC™ results;
100% (70/70) of the laboratories reporting MGIT™ results;
100% (4/4) of the laboratories reporting VersaTREK® results; and
100% (5/5) of the laboratories reporting molecular method results

Rifabutin
Rifabutin (RBT) belongs to same drug class as RMP. It has the same bactericidal mechanism of activity. Less
than 20% RMP resistant strains are susceptible to RBT[3].
Six laboratories tested RBT at the critical concentration of 0.5µg/ml by AP and all reported resistance.

Pyrazinamide
This isolate was susceptible to PZA by BACTECTM , the CLSI- recommended method; however the isolate was
reported resistant by:
100 % (3/3) of the laboratories reporting VersaTREK® results and
31.8% (21/66) of the laboratories reporting MGITTM method.
See Table 1 for the complete results submitted by all participants for Isolate F.

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Table 1: Participant results for M. tuberculosis, Isolate F–resistant to Rifmapin at 1.0µg/ml by AP

Drug
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Rifampin
Rifampin
Rifampin
Rifampin
Rifampin
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Ethionamide
Ethionamide
Ethionamide
Ethionamide
Kanamycin
Kanamycin
Kanamycin
Kanamycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Cycloserine
Cycloserine

Conc.
0.00
0.10
0.20
0.40
1.00
5.00
10.00
0.00
1.00
2.00
5.00
10.00
5.00
20.00
100.00
300.00
0.00
2.50
5.00
7.50
8.00
10.00
1.00
2.00
4.00
6.00
10.00
1.25
2.50
5.00
10.00
0.00
2.50
5.00
6.00
0.00
1.25
2.50
3.00
5.00
10.00
30.00
60.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
3
3
17 2† 19 68 1
69 4
4
25
25
1
1
5
5
27
27 4
4
24
24
1
1
4
4
1
1
5
5
27 27
4
4
70 70
4
4
18 18
3
3
1
1
1
1
1
1
1
1
13
13 45 21 66
1
1
3
3
1
1
15 2† 17
22 1
23
2 1†
3
69 1
70 4
4
2
2
2
2
1
1
3
3
9
9
1
1
50 1
51
25
25 15 3
18
1
1
1
1
7
7
2
2
21
21
1
1
2
2
1
1
2
21 1
22
1
1
2
2
4
4
1
1
1
1
11
11
2
2
10
10
1
1
1
1
1
1
1
1
1
1
2
2
20
20
10
10
1
1

*

VersaTREK®, Hain GenoType®, or Molecular Methods
† Includes borderline results

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Table 1 continued: Participant results for M. tuberculosis, Isolate F– resistant to Rifampin at 1.0µg/ml by
AP

Drug
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Azithromycin
Clarithromycin
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Gatifloxacin
Levofloxacin
Levofloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Rifabutin
Rifabutin
Rifabutin
*

acid
acid
acid
acid

Test Method
AP
BACTEC
MGIT
Results
Results
Results
Conc.
S
R Sum S R Sum S R Sum
2.00 17
17
4.00
1
1
8.00 2
2
10.00 4
4
0.00
1.00
1
1
1.50
1
1
2.00 1
1
1
1
2.50
1
1
4.00 3
3
5.00 1
1
6.00 6
6
8.00
1
1
12.00 2
2
0.00
0.60 1
1
1.00 2
2
2
2
1.25
1
1
2.00 15
15
5
5
4.00 1
1
1
1
0.00
1.00 2
2
2
2
1
1
2.00 6
6
1
1
4.00
1
1
3.00
1
1
3.00
1
1
0.06
1
1
0.12
1
1
0.25
1
1
0.50
3
3
1.00 1
1
0.00
1.50
1
1
2.00
2
2
0.00
0.25
1
1
1.00 1
1
5.00 1
1
0.50
6
6
3
3
1.00
2
2
1
1
2.00
8
8

Other
Results*
S R Sum

1

1

1

1

1

1

1

1

1

1

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods

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Isolate G, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml and
Streptomycin at 2.0µg/ml and 10.0µg/ml by Agar Proportion
Isoniazid

Isoniazid (INH) is the most widely used first-line anti-TB drug. It is the cornerstone of all effective regimens for
the treatment of TB disease and latent infection. INH is a prodrug and is activated by the catalase-peroxidase
enzyme encoded by the katG gene.[4, 5] The target of activated INH is enoyl-acyl-carrier protein reductase
(InhA) which is required for mycolic acid biosynthesis. There are two described mechanisms that account for the
majority of INH resistance[5]. The most common method, mutations in katG, is generally associated with highlevel resistance to INH. Resistance to INH can also occur by mutations in the promoter region of the inhA gene
which are generally associated with low-level resistance to INH and are less frequent than katG mutations. DNA
sequence analysis of inhA and katG of Isolate G revealed a G>C point mutation in the katG locus resulting in
serine being replaced by threonine at codon 315 (Ser315Thr); inhA was wild-type (i.e., no mutations were
detected).
The recommended critical concentration and additional higher concentrations for testing INH using the AP
method are 0.2 µg/ml and 1.0 µg/ml respectively. The equivalent concentrations for BACTEC™, MGIT™, and
VersaTREK® are 0.1 µg/ml and 0.4 µg/ml. It is recommended that all laboratories perform testing at the critical
concentration; if resistant, then testing at the higher recommended concentration should be performed.

Ninety-eight laboratories reported INH results for this isolate at the critical concentration. (Some laboratories
submitted results for more than one method.) This isolate was reported resistant by:
100% (27/27) of the laboratories reporting AP results;
100% (20/20 ) of the laboratories reporting BACTEC™ results;
100% (69/69) of the laboratories reporting MGIT™ results;
100% (4/4) of the laboratories reporting VersaTREK® results.

Laboratories also reported resistance at recommended higher concentration.
The laboratories using Hain GenoType® MTBDRplus and laboratory developed tests reported INH resistance.

Streptomycin
Streptomycin (SM) belongs to the aminoglycoside class of drugs and its primary mechanism of action is to
inhibit the initiation of translations by binding to the 16S rRNA In M. tuberculosis, the genetic basis of
resistance to SM is usually due to mutaions in rrs or rpsL[6].

Seventy-seven laboratories reported SM results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
96.3% (26/27) of the laboratories reporting AP results;

CDC MPEP MTB NTM DST Report for the November 2011 shipment

Page 16

100% (18/18) of the laboratories reporting BACTEC™ results; and
100% (51/51) of the laboratories reporting MGIT™ results.
Laboratories also reported SM resistance at recommended higher concentration.
See Table 2 for the complete results submitted by all participants for Isolate G.

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Page 17

Table 2: Participant results for M. tuberculosis Isolate G–resistant to INH at 0.2µg and 1.0µg /ml and
Streptomycin at 2.0µg/ml and 10.0µg/ml by AP method

Drug
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Rifampin
Rifampin
Rifampin
Rifampin
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Ethionamide
Ethionamide
Ethionamide
Ethionamide
Kanamycin
Kanamycin
Kanamycin
Kanamycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Cycloserine
Cycloserine

Conc.
0.00
0.10
0.20
0.40
1.00
2.00
5.00
10.00
0.00
1.00
2.00
5.00
5.00
20.00
100.00
300.00
0.00
2.50
5.00
7.50
8.00
10.00
1.00
2.00
4.00
6.00
10.00
1.25
2.50
5.00
10.00
0.00
2.50
5.00
6.00
0.00
1.25
2.50
3.00
5.00
10.00
30.00
60.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
3
3
20 20
69 69
4
4
27 27
1
1
1
1
5
5
35 35
4
4
27 27
2
2
1
1
2
2
4
1
1
1
1
5
5
26
26
4
4
70
70 4
4
18
18
3
3
1
1
1
1
14
14 64 2
66
1
1
4
4
1
1
17
17
22 1
23
3
3
70
70 4
4
2
2
3
3
1
1
4
4
9
9
1
1
51 51
1 26 27
18 18
1
1
2
1
1
9
9
3
3
23 23
1
1
2
2
2
2
7 16† 23
1
1
2
2
2
2
4
1
1
1
1
11
11
2
2
10
10
1
1
1
1
1
1
1
1
1
1
2
2
20
20
10
10
1
1

*

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods
† Includes borderline results

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Table 2 Continued: Participant results for M. tuberculosis Isolate G–resistant to INH at 0.2µg and 1.0µg/ml
and Streptomycin at 2.0µg/ml and 10.0µg/ml by AP method

Drug
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Gatifloxacin
Gatifloxacin
Levofloxacin
Levofloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Rifabutin
Rifabutin
Rifabutin

*

acid
acid
acid
acid

Conc.
2.00
4.00
8.00
10.00
0.00
1.00
1.50
2.00
2.50
4.00
5.00
6.00
8.00
12.00
0.00
0.60
1.00
1.25
2.00
4.00
0.00
1.00
2.00
4.00
0.06
0.12
0.25
0.50
1.00
0.00
0.00
1.50
2.00
0.00
0.25
1.00
5.00
5.00
0.50
1.00
2.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
18
18
1
1
2
2
4
4
1
1
1
1
1
1
1
1
1
1
1
1
3
3
1
1
6
6
1
1
2
2
1
1
1
1
2
2
2
2
1
1
15
15
5
5
1
1
1
1
1
1
2
2
2
2
1
1
6
6
1
1
1
1
1
1
1
1
1
1
3
3
1
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
1
1
1
6
6
2
2
2
2
1
1
8
8

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods

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Isolate H, M. tuberculosis–resistant to Streptomycin at 2.0µg/ml by AP method and
Pyrazinamide at 100.0µg/ml by MGIT method.
Streptomycin
As previously stated, streptomycin (SM) belongs to the aminoglycoside class of drugs and its primary mechanism
of action is to inhibit the initiation of translations by binding to the 16S rRNA. In M. tuberculosis, the genetic
basis of resistance to SM is usually due to mutations in rrs or rpsL[6].
Seventy-five laboratories reported SM results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
92.0% (23/25) of the laboratories reporting AP results;
100% (18/18) of the laboratories reporting BACTEC™ results; and
100% (51/51) of the laboratories reporting MGIT™ results.
Laboratories also reported SM resistance at recommended higher concentration.
Pyrazinamide
Pyrazinamide (PZA) is an important first-line drug used with INH and RMP for treatment of tuberculosis. The
role of PZA is to shorten TB treatment to 6 months because it kills a population of persistent and semi-dormant
bacilli in the acidic pH environment in the lesions that are not killed by other drugs. Pyrazinamide is a prodrug
that requires conversion to its active form, pyrazinoic acid, by the pyrazinamidase (PZase) encoded by the pncA
gene of M. tuberculosis. Resistance to PZA is usually caused by diverse nucleotide changes scattered throughout
the pncA gene, and PZA-resistant M. tuberculosis strains lose PZase activity.

.

Eighty-four laboratories reported PZA results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
7.0% (1/14) of the laboratories reporting BACTEC™ results;
75.8% (50/66) of the laboratories reporting MGIT™ results; and
50.0% (2/4) of the laboratories reporting VersaTREK® results.

One laboratory reported susceptible using Laboratory Developed Tests.

Only one out of 14 laboratories reported Isolate H as PZA resistant using BACTEC, the CLSI-recommended
method for PZA testing.
.

Standard culture-based PZA susceptibility tests are difficult to perform as a result of poor buffering of test media,
the use of acidic medium pH that inhibits growth, and excessively large inoculum that reduce the activity of PZA
[7]. Among culture based DST methods, the BACTECTM radiometric method is probably the most reliable and is
currently the reference method for choice for PZA DST [1]. MGIT had widely replaced the BACTECTM
CDC MPEP MTB NTM DST Report for the November 2011 shipment

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radiometric method. However, MGITTM may over report PZA resistance [7, 8]. Tests for PZase activity and for
the detection of mutations in pncA may be used as alternative methods for the detection of PZA resistance in M.
tuberculosis [7, 8].

Isolate H did not have a mutation detected in pncA. Both MGIT tubes used in the PZA DST test (growth control
and PZA-containing tube) were positive for for PZase activity. In addition, only one out of 14 laboratories
reported Isolate H as PZA resistant using BACTEC, the CLSI-recommended method for PZA testing. All of these
results lead us to suspect that the MGITTM DST results were falsely resistant. Further study is needed to ascertain
the exact cause of this problem.

See Table 3 for the complete results submitted by all participants for Isolate H.

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Table 3: Participant results for M. tuberculosis Isolate H–resistant to Streptomycin at 2.0µg/ml by AP
method and Pyrazinamide at 100.0µg/ml by MGIT method

Drug
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Rifampin
Rifampin
Rifampin
Rifampin
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Ethionamide
Ethionamide
Ethionamide
Ethionamide
Kanamycin
Kanamycin
Kanamycin
Kanamycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Cycloserine
Cycloserine

Conc.
0.00
0.10
0.20
0.40
1.00
5.00
10.00
0.00
1.00
2.00
5.00
0.00
5.00
20.00
100.00
300.00
0.00
2.50
5.00
7.50
8.00
10.00
1.00
2.00
4.00
6.00
10.00
1.25
2.50
5.00
10.00
0.00
5.00
6.00
6.00
0.00
2.50
3.00
5.00
10.00
30.00
60.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
3
3
20
20 68
68 4
4
23
23
1
1
5
5
26 1
27 4
4
22
22
1
1
3
3
1
1
5
5
24
24
4
4
69
69 4
4
18
18
3
3
1
1
1
1
1
1
13 1
14 16 50† 66
1
1
2 2
4
1
1
17
17
19 2
21
3
3
69
69 3
3
2
2
3
3
1
1
4
4
8
8
1
1
51 51
2 23 25
18 18
1
1
2
1
1
9
9
3
3
22 22
1
1
1
1
2
2
16 4† 20
1
1
2
2
3
3
1
1
10
10
1
1
9
9
9
9
1
1
1
1
1
1
2
2
17
17
†
7 1
8
1
1

*

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods
† Includes borderline results

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Table 3 Continued: Participant results for M. tuberculosis Isolate H–resistant to Streptomycin at 2.0µg/ml
by AP method and Pyrazinamide at 100.0µg/ml by MGIT method

Drug
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Gatifloxacin
Gatifloxacin
Levofloxacin
Levofloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Rifabutin
Rifabutin
Rifabutin

*

acid
acid
acid
acid

Test Method
AP
BACTEC
MGIT
Results
Results
Results
Conc.
S
R Sum S R Sum S R Sum
2.00 15
15
4.00
1
1
8.00 2
2
10.00 4
4
0.00
1.00
1
1
1.50
1
1
2.00 1
1
1
1
2.50
1
1
4.00 2
2
5.00 1
1
6.00 5
5
8.00
1
1
12.00 2
2
0.00
0.60 1
1
1.00 2
2
2
2
2.00 14
14
4
4
4.00 1
1
1
1
0.00
1.00 2
2
2
2
1
1
2.00 4
4
1
1
4.00
1
1
0.06
1
1
0.12
1
1
0.25
1
1
0.50
2
2
1.00 1
1
0.00
0.00
1.50
1
1
2.00
2
2
0.00
0.25
1
1
1.00 1
1
0.50 6
6
1
1
1.00 2
2
1
1
2.00 7
7

Other
Results*
S R Sum

1

1

1

1

1

1

1
1

1
1

1

1

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods

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Isolate I, M. tuberculosis–susceptible to first-line and second-line drugs
This isolate is susceptible to all first and second line drugs at recommended testing concentrations.
Isolate I was reported resistant by:
Laboratories using AP methods:
5.3% (1/19) reported resistant to Ethambutol
10.5% (2/19) reported resistant to Ethionamide
Laboratories using BACTECTM method:
4.8% (1/21) reported resistant to Isoniazid
5.6% (1/18) reported resistant to Ethambutol
15.8% (3/19) reported resistant to Streptomycin
Laboratories using MGITTM method:
7.6% (5/66) reported resistance to Pyrazinamide
Laboratories using VersaTREK® method:
66.7% (2/3) reported resistance to Pyrazinamide
See Table 4 for the complete results submitted by all participants for Isolate I.

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Table 4: Participant results for M. tuberculosis, Isolate I– susceptible to first-line and second-line drugs

Drug
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Rifampin
Rifampin
Rifampin
Rifampin
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Ethionamide
Ethionamide
Ethionamide
Ethionamide
Kanamycin
Kanamycin
Kanamycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Cycloserine
Cycloserine

Conc.
0.00
0.10
0.20
0.40
1.00
5.00
10.00
0.00
1.00
2.00
5.00
0.00
5.00
20.00
100.00
300.00
0.00
2.50
5.00
7.50
8.00
10.00
1.00
2.00
4.00
6.00
10.00
1.25
2.50
5.00
10.00
0.00
5.00
6.00
0.00
2.50
3.00
5.00
10.00
30.00
60.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
3
3
20 1
21 68
68 4
4
21
21
1
1
5
5
28
28 3
3
21
21
1
1
3
3
1
1
5
5
23
23
4
4
69
69 4
4
18
18
2
2
1
1
1
1
1
1
14
14 61 5
66
1
1
1 2
3
1
1
17 1
18
18 1
19
3
3
69
69 3
3
2
2
3
3
1
1
4
4
7
7
1
1
49 1
50
23
23 16 3
19
1
1
6
6
2
2
19
19
1
1
1
1
17 2† 19
1
1
2
2
2
3
3
1
1
10
10
1
1
8
8
1
1
1
1
1
1
1
1
17
17
8
8
1
1

*

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods
† Includes borderline results

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Table 4 Continued: Participant results for M. tuberculosis, Isolate I– susceptible to first-line and secondline drugs

Drug
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Gatifloxacin
Levofloxacin
Levofloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Rifabutin
Rifabutin
Rifabutin
*

acid
acid
acid
acid

Test Method
AP
BACTEC
MGIT
Results
Results
Results
Conc.
S
R Sum S R Sum S R Sum
2.00 14
14
4.00
1
1
8.00 2
2
10.00 4
4
0.00
1.00
1
1
1.50
1
1
2.00 1
1
1
1
4.00 2
2
5.00 1
1
6.00 5
5
8.00
1
1
12.00 2
2
0.00
0.60 1
1
1.00 1
1
1
1
2.00 14
14
4
4
4.00 1
1
1
1
0.00
1.00 1
1
1
1
1
1
2.00 4
4
1
1
4.00
1
1
0.06
1
1
0.12
1
1
0.25
1
1
0.50
1
1
1.00 1
1
0.00
1.50
1
1
2.00
1
1
0.00
0.25
1
1
1.00 1
1
0.50 6
6
1
1
1.00 2
2
2.00 7
7

Other
Results*
S R Sum

1

1

1

1

1

1

1

1

1

1

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods

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Isolate J, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml; Ethambutol at
5.0µg/ml; Amikacin at 4.0µg/ml; Capreomycin at 10.0µg/ml; and Kanamycin at 5.0µg/ml
by Agar Proportion 7H10 method
Isoniazid

As noted in the section for Isolate G, there are two described mechanisms that account for the majority of INH
resistance. Mutations in katG are generally associated with high-level resistance to INH. Mutations in the
promoter region of the inhA gene are generally associated with low-level resistance to INH and are less frequent
than katG mutations. DNA sequence analysis of inhA and katG of Isolate J revealed a G>C point mutation in the
katG locus resulting in serine being replaced by threonine at codon 315 (Ser315Thr); inhA was wild-type (i.e., no
mutations were detected).

Ninety-seven laboratories reported INH results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
100% (27/27) of the laboratories reporting AP results;
100% (20/20) of the laboratories reporting BACTEC™ results; and
100% (69/69) of the laboratories reporting MGIT™ results;
100% (3/3) of the laboratories reporting VersaTREK® results.
Laboratories also reported 100% (68/68) resistance when tested at recommended higher concentrations
for INH.
Laboratories using molecular methods (Hain GenoType® MTBDRplus, and Laboratory Developed Tests)
reported INH resistance.

Ethambutol
Ethambutol (EMB) is an important first-line drug for the treatment of tuberculosis and is used in combination
with INH, RMP, and PZA to prevent emergence of drug resistance. EMB is a bacteriostatic agent that is active
against growing bacilli and has no effect on non-replicating bacilli [5]. EMB targets the arabinosyl transferases
(embCAB operon), thereby inhibiting the biosynthesis of the cell wall components arabinogalactan and
lipoarabinomannan [5, 9].
Conventional culture based methods of EMB susceptibility testing are problematic [10, 11]. Sequence analysis of
EMB-resistant clinical isolates has shown that EMB resistance is associated primarily with missense mutations
within the EMB resistance determining region of the gene embB at codons 306, 406, and 497[4, 9].
DNA sequence analysis of embB of Isolate J revealed a mutation resulting methionine replaced by isoleucine at
codon 306 (Met306Ile). This mutation is highly associated with EMB resistance [12].

Ninety-five laboratories reported EMB results for this isolate at the critical concentration. (Some laboratories
submitted results from more than one method.) This isolate was reported resistant by:
80% (20/25 ) of the laboratories reporting AP results;

CDC MPEP MTB NTM DST Report for the November 2011 shipment

Page 27

93.8% (15/16) of the laboratories reporting BACTEC™ results;
79.7% (55/69) of the laboratories reporting MGIT™ results;
0.0% (0/3) of the laboratories reporting VersaTREK® results.
The laboratory using Hain GenoType® MTBDRsl also reported EMB resistance.

Second- line drugs
Isolate J was also resistant to Amikacin, Capreomycin, and Kanamycin by the AP method. Mutations in the 16S
rRNA gene (rrs) have been associated with resistance to second-line injectable drugs [13]. DNA sequence
analysis of the rrs gene of Isolate J revealed a mutation resulting alanine replaced by glycine at codon 1401
(Ala1401Gly) which is highly associated with resistance to second line injectable drugs.
Amikacin
Fourteen laboratories reported Amikacin results for this isolate. (Some laboratories submitted results from
more than one method.) This isolate was reported resistant by:
100% (3/3) of the laboratories reporting AP results at the recommended critical concentration.
The laboratory using Hain GenoType® MTBDRsl also reported Amikacin resistance.

Capreomycin
Twenty-five laboratories reported Capreomycin results for this isolate. (Some laboratories submitted
results from more than one method.) This isolate was reported resistant by:
80% (16/20) of the laboratories reporting AP results at the recommended critical concentration.
The laboratory using Hain GenoType® MTBDRsl also reported Capreomycin resistance.

Kanamycin
Twenty-three laboratories reported Kanamycin results for this isolate. (Some laboratories submitted
results from more than one method.) This isolate was reported resistant by:
100% (21/21) of the laboratories reporting AP results at the recommended critical concentration.
The laboratory using Hain GenoType® MTBDRsl also reported Kanamycin resistance.

See Table 5 for the complete results submitted by all participants for Isolate J.

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Table 5: Participant results for Isolate J, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and 1.0µg/ml;
Ethambutol at 5.0µg/ml; Amikacin at 4.0µg/ml; Capreomycin at 10.0µg/ml; and Kanamycin at 5.0µg/ml by
Agar Proportion 7H10 method

Drug
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Isoniazid
Rifampin
Rifampin
Rifampin
Rifampin
Pyrazinamide
Pyrazinamide
Pyrazinamide
Pyrazinamide
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Ethambutol
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Streptomycin
Ethionamide
Ethionamide
Ethionamide
Ethionamide
Kanamycin
Kanamycin
Kanamycin
Kanamycin
Kanamycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Capreomycin
Cycloserine
Cycloserine

Conc.
0.00
0.10
0.20
0.40
1.00
2.00
5.00
10.00
0.00
1.00
2.00
5.00
5.00
20.00
100.00
300.00
0.00
2.50
5.00
7.50
8.00
10.00
1.00
2.00
4.00
6.00
10.00
1.25
2.50
5.00
10.00
0.00
2.50
5.00
6.00
10.00
0.00
1.25
2.50
3.00
5.00
10.00
30.00
60.00

Test Method
AP
BACTEC
MGIT
Other
Results
Results
Results
Results*
S
R Sum S R Sum S R Sum S R Sum
3
3
20 20
69 69
3
3
27 27
1
1
1
1
5
5
36 36
3
3
27 27
2
2
1
1
2
2
4
1
1
1
1
5
5
26
26
4
4
70
70 3
3
18
18
3
3
1
1
1
1
13 1
14 65 2
67
1
1
4
4
1
1
1 15 16
5 20† 25
1
3
4
14 55† 69 3
3
†
1 1
2
4
4
1
1
3
3
11
11
1
1
1
1
50 1
51
26
26 18 2
20
1
1
7
7
2
2
21
21
1
1
2
2
2
14 8† 22
1
1
2
2
2
3 1†
4
1
1
1
1
11 11
3
3
10 10
1
1
1
1
1
1
1
1
1
1
1
1
1 2†
3
4 16 20
1
1
9
1
10
1
1

*

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods
† Includes borderline results

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Table 5 Continued: Participant results for Isolate J, M. tuberculosis–resistant to Isoniazid at 0.2µg/ml and
1.0µg/ml; Ethambutol at 5.0µg/ml; Amikacin at 4.0µg/ml; Capreomycin at 10.0µg/ml; and Kanamycin at
5.0µg/ml by Agar Proportion 7H10 method

Drug
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
p-Aminosalicylic
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Amikacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Ciprofloxacin
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Clofazimine
Gatifloxacin
Levofloxacin
Levofloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Moxifloxacin
Rifabutin
Rifabutin
Rifabutin

*

acid
acid
acid
acid

Test Method
AP
BACTEC
MGIT
Results
Results
Results
Conc.
S
R Sum S R Sum S R Sum
2.00 18
18
4.00
1
1
8.00 2
2
10.00 4
4
0.00
1.00
1
1
1.50
1
1
2.00
1
1
1
1
2.50
1
1
4.00
3
3
5.00
1
1
6.00 1
5
6
8.00
1
1
12.00
2
2
0.00
0.60 1
1
1.00 2
2
2
2
1.25
1
1
2.00 15
15
5
5
4.00 1
1
1
1
0.00
1.00 2
2
2
2
1
1
2.00 6
6
1
1
4.00
1
1
0.06
1
1
0.12
1
1
0.25
1
1
0.50
3
3
1.00 1
1
0.00
1.50
1
1
2.00
2
2
0.00
0.25
1
1
1.00 1
1
5.00 1
1
0.50 6
6
2
2
1.00 2
2
1
1
2.00 8
8

Other
Results*
S R Sum

1

1

1

1

1

1

1

1

1

1

VersaTREK®, Hain GenoType®, XPERT MTB/RIF or Molecular Methods

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Abbreviations Used in This Report
AMK
AP
BACTEC™
bp
BSL
CDC
CIP
CLF
CLSI
CM
CS
DNA
DST
EMB
ETH
HMO
INH
KM
LEV
MGIT™
MOX
MPEP MTB NTM DST

amikacin
agar proportion
BACTEC™ 460TB
base pair
Biosafety Level
Centers for Disease Control and Prevention (CDC)
ciprofloxacin
clofazimine
Clinical Laboratory and Standards Institute
capreomycin
cycloserine
deoxyribonucleic acid
Drug Susceptibility Testing
ethambutol
ethionamide
Health Maintenance Organization
isoniazid
kanamycin
levofloxacin
BACTEC™ MGIT™ 960 (Mycobacteria Growth Indicator Tube)
moxifloxacin
Model Performance Evaluation Program for Mycobacterium tuberculosis
and Nontuberculous Mycobacteria Drug Susceptibility Testing

NIH
NTM
OFX
PAS
PPO
PZA
QRDR
RBT
RMP
RNA
SM
VersaTREK®

National Institutes of Health
Nontuberculous Mycobacteria
ofloxacin
p-aminosalicyclic acid
Preferred Provider Organization
pyrazinamide
quinolone-resistance-determining region
rifabutin
rifampin
ribonucleic acid
streptomycin
VersaTREK®Myco Susceptibility Kit

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References
1.
2.
3.
4.

5.
6.
7.
8.
9.
10.
11.
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13.

Clinical and Laboratory Standards Institute, Susceptibility Testing of Mycobacteria, Nocardia, and Other Aerobic
Actinomycetes; Approved Standard–2nd ed. M24–A2., 2011, CLSI: Wayne, PA.
Almeida Da Silva, P.E. and J.C. Palomino, Molecular basis and mechanisms of drug resistance in Mycobacterium
tuberculosis: classical and new drugs. J Antimicrob Chemother 2011. 66(7): p. 1417-30.
Curry, F.J. and Curry International Tuberculosis Center and California Department of Public Health., DrugResistant Tuberculosis: A Survival Guide for Clinicians. Second ed2008.
Campbell, P.J., et al., Molecular detection of mutations associated with first- and second-line drug resistance
compared with conventional drug susceptibility testing of Mycobacterium tuberculosis. Antimicrob Agents
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Zhang, Y. and W.W. Yew, Mechanisms of drug resistance in Mycobacterium tuberculosis. Int J Tuberc Lung Dis,
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Inderllied, B.C., Pfyffer, F. G, Susceptibility Test Methods: Mycobacteria, in Manual of clinical microbiology2003,
ASM Press: Washington, D.C.
Chang, K.C., W.W. Yew, and Y. Zhang, Pyrazinamide susceptibility testing in Mycobacterium tuberculosis: a
systematic review with meta-analyses. Antimicrob Agents Chemother, 2011. 55(10): p. 4499-505.
Chedore, P., et al., Potential for erroneous results indicating resistance when using the Bactec MGIT 960 system for
testing susceptibility of Mycobacterium tuberculosis to pyrazinamide. J Clin Microbiol, 2010. 48(1): p. 300-1.
Starks, A.M., et al., Mutations at embB Codon 306 Are an Important Molecular Indicator of Ethambutol Resistance
in Mycobacterium tuberculosis. Antimicrob Agents Chemother, 2009. 53(3): p. 1061-1066.
Madison, B., et al., Multicenter evaluation of ethambutol susceptibility testing of Mycobacterium tuberculosis by
agar proportion and radiometric methods. J Clin Microbiol, 2002. 40(11): p. 3976-3979.
Angra, P.K., et al., Performance of tuberculosis drug susceptibility testing in u.s. Laboratories from 1994 to 2008. J
Clin Microbiol, 2012. 50(4): p. 1233-9.
Ramaswamy, S.V., et al., Molecular genetic analysis of nucleotide polymorphisms associated with ethambutol
resistance in human isolates of Mycobacterium tuberculosis. Antimicrob Agents Chemother, 2000. 44(2): p. 326336.
Maus, C.E., B.B. Plikaytis, and T.M. Shinnick, Molecular analysis of cross-resistance to capreomycin, kanamycin,
amikacin, and viomycin in Mycobacterium tuberculosis. Antimicrob Agents Chemother, 2005. 49(8): p. 3192-7.

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