Evaluation of low-colony-number counts of Mycobacterium tuberculosis on solid media as a microbiological marker of cross-contamination.
Low-colony-number counts on solid media are considered characteristic of cross-contamination, although they are normally observed in true-positive cultures from some groups of patients. The aim of this study was to evaluate low-yield growth cultures as a microbiological marker for cross-contamination. We evaluated 106 cultures with <15 colonies from 94 patients, and the proportions of false-positive cultures were 0.9% per sample and 1.1% per patient, which indicates that low-yield growth is not a reliable marker of cross-contamination.
Núcleo de Doenças Infecciosas, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, Av. Marechal Campos, 1468, Maruípe, Vitória, Espírito Santo, Brazil.
F K C
FK
Ribeiro
E M
EM
Lemos
D J
DJ
Hadad
S C
SC
Leão
C
C
Viana-Niero
R
R
Dietze
J L
JL
Johnson
K D
KD
Eisenach
M
M
Palaci
D000328:Adult; D000368:Aged; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D015169:Colony Count, Microbial; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D005189:False Positive Reactions; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
D004269:DNA, Bacterial