Abstract：
Twenty samples of minced chicken meat procured from butcher’s shops in León (Spain; 10 samples) and Vila Real (Portugal; 10 samples) were analyzed. Microbial concentrations (log10 cfu/g) of 7.53 ± 1.02 (viable aerobic microbiota), 7.13 ± 1.07 (psychrotrophic microorganisms), and 4.23 ± 0.88 (enterobacteria) were found. The detection method described in the UNE-EN ISO 11290-1 standard (based on isolation from the chromogenic medium OCLA) with confirmation by the polymerase chain reaction (PCR; lmo1030) (OCLA−PCR), revealed Listeria monocytogenes in 14 samples (70.0% of the total), nine of Spanish origin and five of Portuguese (p > 0.05). The levels of viable and inactivated L. monocytogenes in the samples were determined with a q-PCR using propidium monoazide (PMAxx) as a viability marker. Seven samples tested positive both with the OCLA−PCR and with the q-PCR, with estimated concentrations of viable cells varying between 2.15 log10 cfu/g (detection limit) and 2.94 log10 cfu/g. Three samples tested negative both with the OCLA−PCR and with the q-PCR. Seven samples were positive with the OCLA−PCR, but negative with the q-PCR, and three samples tested negative with the OCLA−PCR and positive with the q-PCR. The percentage of viable cells relative to the total ranged between 2.4% and 86.0%. Seventy isolates of L. monocytogenes (five from each positive sample) were classified in PCR serogroups with a multiplex PCR assay. L. monocytogenes isolates belonged to serogroups IIa (52 isolates; 74.3%), IIc (7; 10.0%), IVa (2; 2.9%), and IVb (9; 12.9%). The susceptibility of the 70 isolates to 15 antibiotics of clinical interest was tested. The strains presented resistance to between three and eight antibiotics. The average number of resistances was greater (p < 0.001) among strains isolated from Spanish samples (6.20 ± 1.08), than in those from Portugal (5.00 ± 1.08). In both groups of strains, a prevalence of resistance higher than 95% was observed for oxacillin, cefoxitin, cefotaxime, and cefepime. The need to handle minced chicken meat correctly, taking care to cook it sufficiently and to avoid cross-contamination, so as to reduce the danger of listeriosis, is emphasized. A combination of culture-dependent and culture-independent methods offers complementary routes for the detection in food of the cells of L. monocytogenes in various different physiological states.
摘要：
分析了从莱昂（西班牙；10个样品）和维拉雷亚尔（葡萄牙；10个样品）的肉店采购的20个鸡肉末样品。微生物浓度（log10cfu/g）为7.53±1.02（活的需氧微生物群），7.13±1.07（嗜冷性微生物），发现4.23±0.88（肠杆菌）。UNE-ENISO11290-1标准中描述的检测方法（基于从显色培养基OCLA中分离），并通过聚合酶链反应（PCR;lmo1030）（OCLA-PCR）进行确认，在14个样本中发现了单核细胞增生李斯特菌（占总数的70.0%），西班牙血统9个，葡萄牙血统5个（p>0.05）。使用单叠氮丙啶(PMAxx)作为生存力标记,用q-PCR测定样品中活的和灭活的单核细胞增生李斯特菌的水平。7个样本的OCLA-PCR和q-PCR均呈阳性，估计的活细胞浓度在2.15log10cfu/g（检测限）和2.94log10cfu/g之间变化。三个样品用OCLA-PCR和q-PCR均测试为阴性。七个样本的OCLA-PCR呈阳性，但q-PCR为阴性,三个样本用OCLA-PCR检测为阴性，q-PCR检测为阳性。活细胞相对于总数的百分比介于2.4%和86.0%之间。通过多重PCR测定法将70株单核细胞增生李斯特菌分离株（每个阳性样品中5株）分类到PCR血清组中。单核细胞增生李斯特菌分离株属于IIa血清群（52株；74.3%），IIc（7；10.0%），IVa（2；2.9%），和IVb（9；12.9%）。测试了70个分离株对15种临床感兴趣的抗生素的敏感性。这些菌株对3至8种抗生素具有抗性。从西班牙样品中分离出的菌株的平均抗性数量更大（p<0.001）（6.20±1.08），比葡萄牙的(5.00±1.08)。在两组菌株中，苯唑西林的耐药率高于95%，头孢西丁,头孢噻肟,还有头孢吡肟.正确处理鸡肉末的需要，注意煮得足够多，避免交叉污染，为了减少李斯特菌病的危险，强调。培养依赖性和培养非依赖性方法的组合为在食物中检测处于各种不同生理状态的单核细胞增生李斯特菌的细胞提供了补充途径。
