Advanced Diagnostic Laboratories

Appropriate phenotypic and genotypic susceptibilities for antimicrobial susceptibility testing of Acid Fast Bacilli

Test Code

APPRO

Description

This is the recommended orderable for susceptibility testing. Selection of this orderable triggers the appropriate phenotypic and molecular drug resistance testing for each type of organism (Table 1). Note that testing is not performed, reported, or billed if it is not appropriate for the organism.

APPRO can be ordered on clinical specimens sent for culture. If an organism is grown, the appropriate drugs are automatically added; testing will not be performed if no organism is cultured. APPRO may also be ordered on isolates. Note that if a customized selection of antibiotics are needed, they can be selected individually. See "Individual Drug Testing for Acid Fast Bacilli" for the full selection of antibiotics that can be ordered.

Table 1. Phenotypic and genotypic susceptibilities performed based on the organism type when APPRO is ordered.

Organism	Phenotypic testing		Molecular drug resistance testing (see AFB6 for more details)
Organism	Billing code	Drugs	Billing code	Testing
M. avium complex	NTM13	AMK, CIP, CLO, CLR, DOX, LZD, MIN, MXF, RFB, RIF, STR, TMP/SXT	NTMDR	Macrolides and aminoglycosides
Slowly growing mycobacteria other than M. avium complex and fastidious mycobacteria	NTM13	AMK, CIP, CLO, CLR, DOX, LZD, MIN, MXF, RFB, RIF, STR, TMP/SXT	N/A	Does not apply to these organisms
Fastidious slowly growing mycobacteria such as M. haemophilum	NTM3	CLO, LZD	N/A	Does not apply to these organisms.
M. tuberculosis complex (First line drugs)	MTB2	INH, PZA, RIF, EMB	MTB4T	Rifampin and isoniazid
Drug resistant M. tuberculosis complex (Second line drugs)	MTB1	AMK, CAP, CS, EMB, ETH, INH, KAN, PAS, RIF, STR	MTB5T	Fluoroquinolones, aminoglycosides, and kanamycin
M. abscessus and M. chelonae	NTM6, NTM6V (vet)	AMK, CLR, CIP, CLO, DOX, FOX, IPM, LZD, MXF, TGC, TOB, TMP/SXT Nonvalidated, research use only: AUG, FEP, AXO KAN, GEN, FOT, AZM, MIN, CLO/AMK	NTMDR	Inducible and acquired macrolides, aminoglycosides
Other rapidly growing mycobacteria (e.g. M. fortuitum, M. peregrinum)	NTM6, NTM6V (vet)	AMK, CLR, CIP, CLO, DOX, FOX, IPM, LZD, MXF, TGC, TOB, TMP/SXT Nonvalidated, research use only: AUG, FEP, AXO KAN, GEN, FOT, AZM, MIN, CLO/AMK	N/A	Does not apply to these organisms
Partial acid fast bacteria (e.g. Nocardia sp., Gordonia sp., Tskuamurella sp.)	NTM4, NTM4V (vet)	AMK, AUG, AXO, CIP, CLR, DOX, IPM, LZD, MIN, MXF, TOB, TMP/SXT Nonvalidated, research use only: AZM, CLO, FEP, FOT, GEN, KAN, FOX	N/A	Does not apply to these organisms

Table 2. Drug abbreviations (used on the requisition)

Abbreviation	Drug	Abbreviation cont'd	Drug cont'd
AMK	Amikacin	INH	Isoniazid
AUG	Augmentin	IPM	Imipenem
AXO	Ceftriaxone	KAN	Kanamycin
AZM	Azithromycin	LZD	Linezolid
CIP	Ciprofloxacin	MIN	Minocycline
CLO	Clofazimine	MXF	Moxifloxacin
CLO/AMK	Clofazimine & Amikacin synergy	OFX	Ofloxacin
CLR	Clarithromycin	OMC	Omadacycline
CAP	Capreomycin	PAS	p-Aminosalicyclic acid
CS	Cycloserine	PZA	Pyrazinamide
DOX	Doxycycline	RFB	Rifabutin
EMB	Ethambutol	RIF	Rifampin
ETH	Ethionamide	RIF/EMB	Rifampin & Ethambutol synergy
FEP	Cefepime	STR	Streptomycin
FOT	Cefotaxime	TGC	Tigecycline
FOX	Cefoxitin	TMP/SXT	Trimethoprim/sulfamethoxazole
GEN	Gentamicin	TOB	Tobramycin

Collect

An identified isolate is required for testing (does not necessarily apply to veterinary rapidly growing isolates).

This test can be ordered on a clinical specimen that has been sent to our laboratory for isolation and identification of mycobacteria. See specimen requirements for culture of mycobacteria from a clinical specimen (AFB1, AFB3 or AFB7)
This test can also be ordered on organisms identified elsewhere. Pure mycobacterial isolates should be sent in solid media such as a Middlebrook slant (7H10 or 7H11), Lowenstein-Jensen (LJ) slant, or in broth (7H9, MGIT, MP BACT/Alert, VersaTrek).
Specimen Volume: Laboratory must receive visible growth of an isolate on solid media or an isolate in broth media (≥3 mL).

Unacceptable Conditions

Cultures received with incomplete identifiers.
Mixed cultures; Note that prior to rejection, attempts will be made to isolate organisms. A re-isolation charge will be applied in these cases.
Cultures containing mold.
Solid media with insufficient growth.
Cultures submitted on agar plates.
Liquid media with < 2 mL.
Leaking specimens.

Storage Transport Temp

Transport or mail isolates at ambient temperature. For nontuberculous mycobacteria (NTM), follow IATA/ DOT category B and for M. tuberculosis complex isolates, follow IATA/DOT category A requirements for shipping biological materials.

Stability

Isolate at ambient temperature

Performed

Typically all days

Methodology

Phenotypic susceptibilities are performed using agar proportion, both microdilution, or broth macrodilution methods. Molecular amplification based methods are used for analysis of genotypic markers of drug resistance.

Turnaround Time

MIC's for M. tuberculosis complex and other slowly growing mycobacteria are reported 4 to 6 weeks after a pure culture is achieved.
MIC's for rapidly growing mycobacteria and aerobic actinomycetes are reported 2 to 3 weeks after a pure culture is achieved.

Department

Infectious Disease Laboratory, Mycobacteriology

Study Offerings

RUO
CAP/CLIA

Related Tests

NTM13, AFB6, MTB1, MTB2, NTM4, NTM4V, NTM6, NTM6V, NTMDR, NTM15

CPT Code

Test code performed within APPRO	CPT Code	Billing Code
MTB1	87190 x10	MTBP1
MTB2	87188 x5	MTBP2
NTM4	87186	NTMP4
NTM4V	87186	NTP4V
NTM6	87186	NTMP6
NTM6V	87186	NTMPV
NTM13	87186	NTM13
NTMDR (NTDR2 or NTDR3 for additional organisms)	87798 x2	NTMDR
MASDR (MASD2 or MASD3 for additional organisms)	87900	MASDR
MTB4T or MTB4S	87798 x2	MTB4T or MTB4S
MTB5T or MTB5S	87798 x 3	MTB5T or MTB5S