Biomaterial Database

Direct drug susceptibility test for tubercle bacilli by the sputum swab culture method. 2000

S Mathew, and N G Nair, and S Radhakrishna, and P R Gangadharam

Tuberculosis Research Center, Chennai, India. trcicmr@giasmd01.vsnl.net.in

OBJECTIVE To develop a simple, inexpensive method for testing direct drug susceptibility of tubercle bacilli to isoniazid (INH) and streptomycin (SM) which can be adopted for use even in remote parts of the world. METHODS Using 239 smear-positive sputum specimens obtained from an equal number of patients, a comparison was made between the direct swab susceptibility test and the standard indirect method for INH and SM using Löwenstein-Jensen (L-J) medium. RESULTS There was 95% agreement of results for INH by 6 weeks and 90% for SM by 8 weeks; 96% of INH-resistant cultures could be detected in 5 weeks and 91% of SM-resistant cultures by 8 weeks. The discrepancies in the two tests were virtually symmetrically distributed at 6 and 8 weeks. The speed and efficiency of detection of resistance by the swab method was also assessed in relation to the standard indirect method. For INH, 96% of the cultures were detected by the fifth week, while 66% were detected as early as 2 weeks and 93% by 4 weeks. With SM, 84% were detected by 4 weeks, 89% by 5 weeks and 91% by 8 weeks. CONCLUSIONS This study has indicated the usefulness of the swab method for testing the drug susceptibility of tubercle bacilli. As this method is simple and easy, and does not even require a centrifuge, it has the potential of application even in the remote parts of the world. The material used, Cetavlon (Cetrimide), is inexpensive and easily water soluble, and more importantly, aqueous solutions are self-sterilizing. It should be stressed, however, that the results obtained with this test take the same time as conventional methods, and it can therefore not be considered as a rapid test.

UI	MeSH Term	Description	Entries
D007538	Isoniazid	Antibacterial agent used primarily as a tuberculostatic. It remains the treatment of choice for tuberculosis.	Isonicotinic Acid Hydrazide,Ftivazide,Isonex,Isonicotinic Acid Vanillylidenehydrazide,Phthivazid,Phthivazide,Tubazide,Acid Vanillylidenehydrazide, Isonicotinic,Hydrazide, Isonicotinic Acid,Vanillylidenehydrazide, Isonicotinic Acid
D008826	Microbial Sensitivity Tests	Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).	Bacterial Sensitivity Tests,Drug Sensitivity Assay, Microbial,Minimum Inhibitory Concentration,Antibacterial Susceptibility Breakpoint Determination,Antibiogram,Antimicrobial Susceptibility Breakpoint Determination,Bacterial Sensitivity Test,Breakpoint Determination, Antibacterial Susceptibility,Breakpoint Determination, Antimicrobial Susceptibility,Fungal Drug Sensitivity Tests,Fungus Drug Sensitivity Tests,Sensitivity Test, Bacterial,Sensitivity Tests, Bacterial,Test, Bacterial Sensitivity,Tests, Bacterial Sensitivity,Viral Drug Sensitivity Tests,Virus Drug Sensitivity Tests,Antibiograms,Concentration, Minimum Inhibitory,Concentrations, Minimum Inhibitory,Inhibitory Concentration, Minimum,Inhibitory Concentrations, Minimum,Microbial Sensitivity Test,Minimum Inhibitory Concentrations,Sensitivity Test, Microbial,Sensitivity Tests, Microbial,Test, Microbial Sensitivity,Tests, Microbial Sensitivity
D009169	Mycobacterium tuberculosis	A species of gram-positive, aerobic bacteria that produces TUBERCULOSIS in humans, other primates, CATTLE; DOGS; and some other animals which have contact with humans. Growth tends to be in serpentine, cordlike masses in which the bacilli show a parallel orientation.	Mycobacterium tuberculosis H37Rv
D003470	Culture Media	Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.	Media, Culture
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000904	Antibiotics, Antitubercular	Substances obtained from various species of microorganisms that are, alone or in combination with other agents, of use in treating various forms of tuberculosis; most of these agents are merely bacteriostatic, induce resistance in the organisms, and may be toxic.	Antitubercular Antibiotics
D000995	Antitubercular Agents	Drugs used in the treatment of tuberculosis. They are divided into two main classes: "first-line" agents, those with the greatest efficacy and acceptable degrees of toxicity used successfully in the great majority of cases; and "second-line" drugs used in drug-resistant cases or those in which some other patient-related condition has compromised the effectiveness of primary therapy.	Anti-Tuberculosis Agent,Anti-Tuberculosis Agents,Anti-Tuberculosis Drug,Anti-Tuberculosis Drugs,Antitubercular Agent,Antitubercular Drug,Tuberculostatic Agent,Tuberculostatic Agents,Antitubercular Drugs,Agent, Anti-Tuberculosis,Agent, Antitubercular,Agent, Tuberculostatic,Anti Tuberculosis Agent,Anti Tuberculosis Agents,Anti Tuberculosis Drug,Anti Tuberculosis Drugs,Drug, Anti-Tuberculosis,Drug, Antitubercular
D001431	Bacteriological Techniques	Techniques used in studying bacteria.	Bacteriologic Technic,Bacteriologic Technics,Bacteriologic Techniques,Bacteriological Technique,Technic, Bacteriological,Technics, Bacteriological,Technique, Bacteriological,Techniques, Bacteriological,Bacteriologic Technique,Bacteriological Technic,Bacteriological Technics,Technic, Bacteriologic,Technics, Bacteriologic,Technique, Bacteriologic,Techniques, Bacteriologic
D012680	Sensitivity and Specificity	Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)	Specificity,Sensitivity,Specificity and Sensitivity
D013048	Specimen Handling	Procedures for collecting, preserving, and transporting of specimens sufficiently stable to provide accurate and precise results suitable for clinical interpretation.	Specimen Collection,Collection, Specimen,Collections, Specimen,Handling, Specimen,Handlings, Specimen,Specimen Collections,Specimen Handlings