Departamento de Salud Pública, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Km. 15.5 Carretera a Nogales, Zapopan, Jalisco, México 45110.
J Food Prot. 2013 Dec;76(12):2004-10. doi: 10.4315/0362-028X.JFP-13-109.
The occurrence, serotype diversity, and antimicrobial resistance of Salmonella bacteria in commercial ground beef at retail establishments were investigated. Salmonella was isolated from 135 (56.7%) of 238 ground beef samples collected at the same number of butcher's shops located in three municipalities of Jalisco State, Mexico, during an 11-month period. The isolation frequency differed by municipality (P < 0.05) and was higher (P < 0.05) during the warm season (68.5%) than during the cold season (43.2%). Overall, 25 serotypes and 8 serogroups were identified among 135 Salmonella isolates; predominant were Salmonella group B (9.6%), Salmonella Anatum (8.9%), Salmonella Agona (6.7%), Salmonella Infantis (6.7%), and Salmonella Typhimurium (5.9%). All Salmonella isolates were tested for susceptibility to 11 antimicrobial drugs of human and veterinary use. Resistance to tetracycline was the most commonly observed (40.7%), followed by resistance to streptomycin (35.6%), trimethoprim-sulfamethoxazole (20.7%), and nalidixic acid (19.3%). Thirty-seven Salmonella isolates (27.4%) were multidrug resistant, and the majority corresponded to Salmonella Group B, Salmonella Anatum, and Salmonella Typhimurium. Three Salmonella isolates were resistant to seven different antimicrobials. The frequency of Salmonella in ground beef samples (56.7%) was higher than that observed in our previous investigation on beef carcasses (15.4%) at small abattoirs in the same region of Mexico. This may be a result of increasing contamination at these two points of the raw-beef production chain or may be an effect of the grinding process that facilitates a more-homogeneous pathogen distribution in the product. Poor hygiene, temperature abuse, and practices allowing cross-contamination during ground beef fabrication at these retail establishments increase the consumer's exposure to Salmonella.
本研究调查了商业绞碎牛肉中沙门氏菌的发生情况、血清型多样性和对抗生素的耐药性。在墨西哥哈利斯科州的三个城市，11 个月内从同数家肉店采集的 238 份绞碎牛肉样本中，分离出 135 株（56.7%）沙门氏菌。分离频率因城市而异（P<0.05），且在温暖季节（68.5%）高于寒冷季节（43.2%）（P<0.05）。总体而言，在 135 株沙门氏菌分离株中鉴定出 25 种血清型和 8 个血清群；主要的血清型为沙门氏菌 B 群（9.6%）、沙门氏菌 Anatum（8.9%）、沙门氏菌 Agona（6.7%）、沙门氏菌 Infantis（6.7%）和沙门氏菌 Typhimurium（5.9%）。所有沙门氏菌分离株均进行了对 11 种人类和兽医用抗生素的药敏试验。最常见的耐药性是对四环素（40.7%），其次是对链霉素（35.6%）、磺胺甲噁唑-甲氧苄啶（20.7%）和萘啶酸（19.3%）。37 株沙门氏菌分离株（27.4%）为多重耐药株，主要为沙门氏菌 B 群、沙门氏菌 Anatum 和沙门氏菌 Typhimurium。3 株沙门氏菌分离株对 7 种不同的抗生素耐药。本研究中，商业绞碎牛肉样品中沙门氏菌的检出率（56.7%）高于我们之前在同一地区小屠宰场牛肉胴体上的调查结果（15.4%）。这可能是由于在生牛肉生产链的这两个环节污染增加，也可能是由于绞碎过程使病原体在产品中更均匀地分布。在这些零售点，恶劣的卫生条件、温度滥用以及在绞碎牛肉制作过程中允许交叉污染的做法，增加了消费者接触沙门氏菌的风险。
