[Benzalkonium chloride: unacceptable to sterilize or disinfect medical or dental instruments].
OBJECTIVE
To compare the sporicidal activity of benzalkonium chloride (BKC) with that of glutaraldehyde.


METHODS
A comparative study was conducted at the microbiology laboratory of Facultad de Odontología, Universidad Nacional Autónoma de México. Bacillus subtilis ATCC 9372 spores were exposed to these germicides (1 spore x mL) on a 0.22 mm filter. After completing the contact time the spores were washed and the filters were incubated on nutrient agar for 72 h at 37 degrees C.


RESULTS
BKC did not eliminate B. subtilis spores at the concentration used, not even after increasing contact time to 15 h (900-fold the recommended time). Two percent glutaraldehyde destroyed spores only after 10 h of contact. Urea and sodium chloride showed no sporicidal activity.


CONCLUSIONS
The results confirm that BKC lacks sporicidal activity and confirm that this quaternary ammonium compound is not able to "sterilize" or "disinfect" medical and dental instruments.
Acosta-Gío
E
E
Laboratorio de Microbiología y Control de Infecciones, División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México (UNAM), México, D.F. acostag@servidor.unam.mx
Herrero-Farías
A
A
Mata-Portuguez
V H
VH
D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D003762:Dental Instruments; D003902:Detergents; D004203:Disinfection; D005976:Glutaral; D006801:Humans; D013242:Sterilization; D013525:Surgical Instruments; D013997:Time Factors
D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D003902:Detergents; D005976:Glutaral