单增李斯特菌国标检验培养基质量的比较

Comparison of the Quality of Chinese National Standard Test Media for Listeria monocytogenes

摘要:

通过考察市售单增李斯特菌国标检验培养基对单核细胞增生李斯特氏菌（Listeria monocytogenes，LM，以下简称单增李斯特菌）和非单增李斯特菌的增菌检测效果，比较不同品牌培养基的质量。该研究采用螺旋涂布计数法，定量测定30株单增李斯特菌和9株非单增李斯特菌在4个品牌的李氏增菌肉汤（LB1、LB2）和6个品牌的PALCAM琼脂培养基、李斯特氏菌显色培养基中的生长情况。实验结果表明：30株单增李斯特菌在4个品牌的LB1增菌肉汤中的浓度均值为2.04×108 CFU/mL~4.59×108 CFU/mL；在LB2增菌肉汤中的浓度为2.36×107 CFU/mL~2.69×107 CFU/mL；在D品牌的PALCAM琼脂培养基中的生长率均值为0.55，在其余5个品牌的PALCAM琼脂培养基和6个品牌的李斯特氏菌显色培养基中的生长率均值均超过0.85。30株单增李斯特菌在李氏增菌肉汤（LB1、LB2）、PALCAM琼脂培养基、李斯特氏菌显色培养基中的增菌检测效果存在显著性差异（p<0.05）。4个品牌的李氏增菌肉汤的增菌效果和6个品牌PALCAM琼脂培养基、李斯特氏显色培养基的检测效果存在显著性差异（p<0.01）。该研究结果表明市售单增李斯特菌国标检验培养基质量差异大。

Abstract:

The quality of different brands of commercially available Chinese National Standard (CNS) test media for Listeria monocytogenes (LM) was compared by investigating the enrichment effects of the media on LM and non-LM bacterial strains. Using the spiral spread count method, the growth of 30 LM strains and nine non-LM strains in four brands of the Listeria enrichment broths LB1 and LB2, six brands of PALCAM agar media, and six brands of Listeria chromogenic media was quantitatively determined. Experimental results showed that the average concentrations of the 30 LM strains were 2.04×108~4.59×108 CFU/mL in the four brands of LB1 enrichment broths and 2.36×107~2.69×107 CFU/mL in the LB2 enrichment broths. The average growth rate was 0.55 in PALCAM agar medium D but exceeded 0.85 in the remaining five brands of PALCAM agar media and all six brands of Listeria chromogenic media. Significant differences were observed in the enrichment effects of the 30 LM strains in the Listeria enrichment broths (LB1 and LB2), PALCAM agar media, and Listeria chromogenic media (p<0.05). The enrichment effects of the four brands of Listeria enrichment broths differed significantly from those of the six brands of PALCAM agar media and six brands of Listeria chromogenic media (p<0.01). Our results indicate that quality varies considerably among the various commercially available CNS test media for LM.