[Risk of contamination of trypan blue dye after first use].
OBJECTIVE
To determine the potential risk of contamination of a trypan blue bottle (TB) after first use and after being stored under different temperature and humidity conditions, as well as to identify possible contamination factors, most frequently involved microorganisms and simultaneously evaluate bacteriostatic and bactericide properties of the dye.


METHODS
An experimental and prospective study was carried out, in which 30 TB bottles were divided into 3 groups (A: control, B: refrigerator storage and C: cabinet storage). The dye was suctioned and cultivated in agar blood plates and Sabouraud agar tube. In group A, TB was cultivated immediately after the opening of the bottles (temperature zero - T0), in groups B and C cultivation occurred in T0, T1 (1 day), T2 (2 days), T7 (7 days) and T10 (10 days) after the opening of the bottles. On the 10th day, groups B and C bottles were also submitted to scraping of their inner walls after opening. Concurrently, the inhibitory action measurement test was conducted on the TB dye for the study of bacteriostatic and bactericidal activity.


RESULTS
Cultivation procedures conducted in T0 presented no contamination. Among T1 and T10, added to the scraping there was only one contaminated bottle stored in the refrigerator. The encountered microorganism was Aspergillus niger. It has been proven that the dye does not show bactericide and bacteriostatic properties against the bacteria which were tested.


CONCLUSIONS
Under this study's conditions there was no contamination of the bottles stored in cabinets and 1 bottle (10%) stored in the refrigerator showed contamination after opening and initial use. The source of contamination may possibly be the outer part of the product. TB does not show bactericidal and bacteriostatic properties against the tested bacteria and in the applied concentration.
Faculdade de Ciências Médicas, Santa Casa de Misericórdia São Paulo, São Paulo, SP, Brazil. jbmalta@hotmail.com
João Baptista Nigro Santiago
JB
Malta
Sérgio
S
Felberg
Maria Aparecida Soares
MA
Murça
Maurício Arruda Câmara
MA
Barros
Lycia Mara Genne
LM
Mimica
D001234:Aspergillus niger / Q000302:isolation & purification*; D004396:Coloring Agents / Q000494:pharmacology; D004340:Drug Contamination; D004356:Drug Storage; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D011446:Prospective Studies; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012307:Risk Factors; D013211:Staphylococcus aureus / Q000187:drug effects; D014343:Trypan Blue / Q000494:pharmacology
D004396:Coloring Agents; D014343:Trypan Blue