Different methods to quantify Listeria monocytogenes biofilms cells showed different profile in their viability

Autor(es)

Winkelstroeter, Lizziane Kretli ^[1] ; De Martinis, Elaine C. P. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brazilian Journal of Microbiology; v. 46, n. 1, p. 231-235, MAY 2015.
• Citações Web of Science: 3

Resumo

Listeria monocytogenes is a foodborne pathogen able to adhere and to form biofilms in several materials commonly present in food processing plants. The aim of this study was to evaluate the resistance of Listeria monocytogenes attached to abiotic surface, after treatment with sanitizers, by culture method, microscopy and Quantitative Real Time Polymerase Chain Reaction (qPCR). Biofilms of L. monocytogenes were obtained in stainless steel coupons immersed in Brain Heart Infusion Broth, under agitation at 37 degrees C for 24 h. The methods selected for this study were based on plate count, microscopic count with the aid of viability dyes (CTC-DAPI), and qPCR. Results of culture method showed that peroxyacetic acid was efficient to kill sessile L. monocytogenes populations, while sodium hypochlorite was only partially effective to kill attached L. monocytogenes (p < 0.05). When, viability dyes (CTC/DAPI) combined with fluorescence microscopy and qPCR were used and lower counts were found after treatments (p < 0.05). Selective quantification of viable cells of L. monocytogenes by qPCR using EMA revelead that the pre-treatment with EMA was not appropriate since it also inhibited amplification of DNA from live cells by ca. 2 log. Thus, the use of CTC counts was the best method to count viable cells in biofilms. (AU)

• Processo FAPESP: 07/56720-0 - Formacao de biofilmes por listeria monocytogenes: fatores de estresse e avaliacao de viabilidade celular.
• Beneficiário: Elaine Cristina Pereira de Martinis
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 06/05574-1 - Aplicacao de reacao da polimerase em cadeia em tempo real para a avaliacao da formacao de biofilmes por listeria monocytogenes.
• Beneficiário: Lizziane Kretli Winkelströter Eller
• Modalidade de apoio: Bolsas no Brasil - Mestrado