Folsom James P, Siragusa Gregory R, Frank Joseph F
Department of Food Science and Technology, University of Georgia, Athens 30602-7610, USA.
J Food Prot. 2006 Apr;69(4):826-34. doi: 10.4315/0362-028x-69.4.826.
Strains of Listeria monocytogenes differ in their ability to form biofilms. The objectives of this study were to determine whether genetically related strains have similar biofilm-forming capacities and what effect nutrient concentration has on the ability of different strains to produce biofilms. Biofilms of 30 strains of L. monocytogenes, obtained from a variety of sources were grown on stainless steel in tryptic soy broth (TSB) or in a 1:10 dilution of TSB (DTSB) for 24 h at 32 degrees C. The amount of biofilm formed was determined with image analysis after cells were stained with bisBenzimide H 33258 (Hoechst 33258). The strains were genetically subtyped by repetitive element sequence-based PCR (rep-PCR) with the primer set rep-PRODt and rep-PROG5. Data were analyzed with an analysis of variance and Duncan's multiple range test. Eleven strains produced the same amount of biofilm in both media. Fourteen strains produced more biofilm in TSB than in DTSB. Five strains produced more biofilm in DTSB than in TSB. Serotype 4b strains produced more biofilm in TSB than did serotype 1/2a strains, whereas serotype 1/2a strains produced more biofilm in DTSB than did serotype 4b strains. Growth in DTSB resulted in decreased biofilm accumulation for serotype 4b strains. There was no correlation between genetic subtype and the amount of biofilm accumulation. These results indicate that strains of serotype 1/2a and serotype 4b differ in the regulation of their biofilm phenotype. The poor biofilm accumulation of serotype 4b isolates when grown in DTSB could be a factor in the predominance of serogroup 1/2 strains in food processing plants, where nutrients may be limited.
单核细胞增生李斯特菌的菌株在形成生物膜的能力上存在差异。本研究的目的是确定基因相关的菌株是否具有相似的生物膜形成能力，以及营养物浓度对不同菌株产生生物膜的能力有何影响。从各种来源获得的30株单核细胞增生李斯特菌菌株的生物膜，在32℃下于胰蛋白胨大豆肉汤（TSB）或TSB的1:10稀释液（DTSB）中在不锈钢上培养24小时。在用双苯甲酰亚胺H 33258（Hoechst 33258）对细胞进行染色后，通过图像分析确定形成的生物膜量。使用引物组rep - PRODt和rep - PROG5通过基于重复元件序列的PCR（rep - PCR）对菌株进行基因亚型分析。数据采用方差分析和邓肯多重极差检验进行分析。11株菌株在两种培养基中产生的生物膜量相同。14株菌株在TSB中产生的生物膜比在DTSB中多。5株菌株在DTSB中产生的生物膜比在TSB中多。4b血清型菌株在TSB中产生的生物膜比1/2a血清型菌株多，而1/2a血清型菌株在DTSB中产生的生物膜比4b血清型菌株多。在DTSB中生长导致4b血清型菌株的生物膜积累减少。基因亚型与生物膜积累量之间没有相关性。这些结果表明，1/2a血清型和4b血清型菌株在生物膜表型的调控上存在差异。4b血清型分离株在DTSB中生长时生物膜积累较差，这可能是食品加工厂中1/2血清群菌株占优势的一个因素，因为那里的营养物质可能有限。
