Johnson James R, Porter Stephen B, Johnston Brian, Thuras Paul, Clock Sarah, Crupain Michael, Rangan Urvashi
VA Medical Center and University of Minnesota, Minneapolis, Minnesota, USA
VA Medical Center and University of Minnesota, Minneapolis, Minnesota, USA.
Appl Environ Microbiol. 2017 Mar 2;83(6). doi: 10.1128/AEM.02956-16. Print 2017 Mar 15.
Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label ("organic," "no antibiotics," and "natural"). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC ( = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. We found that among isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled "organic" were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled "organic," pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent isolates.
鸡肉制品被认为是向消费者传播耐抗菌药物和肠外致病性（ExPEC）细菌的载体。为了在当前对食用动物抗菌药物使用高度关注的时代重新评估这一假设，我们分析了2013年《消费者报告》全国调查中的175株鸡源分离株。通过聚合酶链反应（PCR）筛选分离株中ExPEC定义的毒力基因。对25株ExPEC分离株（175株中的12%）和随机选择的2:1比例的50株非ExPEC分离株进行系统发育/克隆背景和毒力基因型评估，以与其耐药谱以及零售包装标签上的声明（“有机”、“无抗生素”和“天然”）进行比较。与非ExPEC分离株的结果相比，ExPEC分离株组中B2系统发育群分离株的患病率更高（44%对4%；<0.001），A系统发育群分离株的患病率更低（4%对30%；=0.001），多个个体毒力基因的患病率更高，毒力得分更高（中位数，11[范围，4至16]对8[范围，1至14]；=0.001），耐药得分也更高（中位数，4[范围，0至8]对3[范围，0至10]；<0.001）。所有5株序列类型131（ST131）分离株均为ExPEC（=0.003），与其他测试分离株一样具有广泛耐药性，且毒力得分高于其他测试分离株（中位数，12[范围中值，11至13]对8[范围，1至16]；=0.005）。有机标签预示着较低的耐药得分（中位数，2[范围，0至3]对4[范围，0至10]；=0.008），但在ExPEC状态或毒力得分方面无差异。这些发现证明在美国零售鸡肉产品中存在大量耐抗菌药物的ExPEC分离株，包括来自ST131的分离株，这表明存在潜在的公共卫生威胁。我们发现，在2013年美国各地购买的零售鸡肉制品分离株中（其中许多分离株具有广泛的抗生素耐药性），少数分离株的基因图谱表明其有能力在人类中引起肠外感染，如尿路感染，这意味着存在食源性疾病风险。尽管来自标有“有机”标签产品的分离株抗生素耐药性不如其他分离株广泛，但它们的毒力似乎并不低。这些发现表明，美国的零售鸡肉产品，即使标有“有机”标签，也对消费者构成潜在健康威胁，因为它们被广泛抗生素耐药且可能具有毒力的分离株污染。
