次致死乙醇處理影響Cronobacter sakazakii在消毒劑和其他後續一些致死環境下之存活

Abstract

本研究探討Cronobacter sakazakii BCRC13988經5%次致死乙醇濃度處理60 min後，於後續壓力環境包括20% NaCl、10 ppm結晶紫、2% Clidox-SR(含氯消毒劑)、0.1% QuatricideR (四級銨消毒劑)、抗生素、和發酵乳冷藏5℃期間之存活情形。並進一步探討次致死乙醇處理對C. sakazakii之生物膜產生、胞內物質洩漏以及在不同碳氮源環境下生長之影響。結果發現，此乙醇處理能顯著提升C. sakazakii於20% NaCl、Clidox-SR和QuatricideR之耐受性，然而卻降低C. sakazakii在結晶紫(10 ppm)存在下之耐受性。在所測試之條件下，次致死乙醇處理可提升C. sakazakii在以Str. thermophilus製成之發酵乳中冷藏期間之存活，但未改變菌體對於對於抗生素(ampicillin、chloramphenicols、streptomycin、tetracycline、ciprofloxacin)之敏感性。此外，次致死乙醇處理可提升菌體在TSB中生長時生物膜之形成量，也會使菌體破損及皺狀，並增加了胞內物質(260 nm, 280 nm吸光物質)之洩漏。

In the present study, Cronobacter sakazakii was exposed to a sub-lethal dose of 5% ethanol for 60 min. The effect of ethanol shock on the survival of C. sakazakii subjected to subsequent adverse conditons including high sodium chloride concentration (20%), crystal violet (10 ppm), 2% Clidox-SR (chlorine-containing disinfectant), 0.1%,QuatricideR (quaternary ammonium compound), antibiotics, and during the refrigerated storage of lactic fermented milk was investigated. Additionally, the effect of ethanol shock on the biofilm formation of C. sakazakii, leakage of intracellar materials, and the growth of C. sakazakii in the presence of various carbon and nitrogen sources were also investigated. Results revealed that ethanol shock cells significantly (p < 0.05) enhanced the resistance of C. sakazakii to high sodium chloride concentration and sanitizers (chlorine and quaternary) but reduced the tolerance in presence of crystal violet (10 ppm). Ethanol shock treatments increased the Survival of C. sakazakii in the lactic fermented milk prepared with Str. thermophilus during refrigerated storage. However, susceptibilities of ethanol-shocked C. sakazakii to antibiotics (ampicillin, chloramphenicols, streptomycin, tetracycline, ciprofloxacin) showed no significant difference (p > 0.05). Furthermore, ethanol shock increased the biofilm formation of C. sakazakii when incubated in TSB, caused the damage and disruption of the ethanol-shocked cells, and increased the leakage of the intracellular 260 and 280 nm-absorbing materials.