Comparison among three methods for mycobacteria identification.
OBJECTIVE
To compare three methods: Biochemical tests, high-performance liquid chromatography (HPLC) and polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP), for the identification of mycobacteria, and to perform a cost-benefit analysis to define an optimum identification algorithm.


METHODS
One-hundred-and-seven mycobacteria isolates were identified by the three methods at Instituto de Diagnóstico y Referencia Epidemiológicos, between February of 1999 and January of 2000 and the results were compared with those of a reference laboratory using the Q-Cochran statistical test.


RESULTS
PCR-RFLP was the most rapid and specific procedure but also the most expensive; biochemical tests excelled for identification of Mycobacterium tuberculosis, but were lengthy and expensive for other mycobacteria; HPLC ranked in the middle for price, speed and specificity.


CONCLUSIONS
Considering the expected proportion of M. tuberculosis, the following algorithm was proposed: Initially, biochemical tests should be performed; if the results indicate a non-tuberculous mycobacteria, the isolate should be analyzed with HPLC; if results are unclear, the isolate should be analyzed using PCR-RFLP. Isolates showing a previously undescribed PCR-RFLP pattern should be characterized by DNA sequencing.
Mondragón-Barreto
M
M
Departamento de Biología Molecular y Departamento de Micobacterias, Instituto de Diagnóstico y Referencia Epidemiológicos, México, D.F., México.
Vázquez-Chacón
C A
CA
Barrón-Rivero
C
C
Acosta-Blanco
P
P
Jost
K C
KC
Balandrano
S
S
Olivera-Díaz
H
H
D001426:Bacterial Proteins; D015373:Bacterial Typing Techniques / Q000191:economics / Q000379:methods*; D002473:Cell Wall / Q000737:chemistry; D018834:Chaperonin 60; D018833:Chaperonins / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D003365:Costs and Cost Analysis; D004269:DNA, Bacterial / Q000032:analysis; D015252:Deoxyribonucleases, Type II Site-Specific; D004311:Double-Blind Method; D006801:Humans; D009161:Mycobacterium / Q000737:chemistry / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D009164:Mycobacterium Infections / Q000382:microbiology*; D015269:Mycobacterium avium Complex / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D009171:Mycolic Acids / Q000032:analysis; D009170:Nontuberculous Mycobacteria / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012680:Sensitivity and Specificity; D013045:Species Specificity; D013997:Time Factors
D001426:Bacterial Proteins; D018834:Chaperonin 60; D004269:DNA, Bacterial; D009171:Mycolic Acids; C074119:heat-shock protein 65, Mycobacterium; D015252:Deoxyribonucleases, Type II Site-Specific; C024403:GGCC-specific type II deoxyribonucleases; C032823:GGTNACC-specific type II deoxyribonucleases; D018833:Chaperonins