Graduate School of Human Life Science, Osaka City University, Osaka, Japan.
Division of Microbiology, Osaka Institute of Public Health, Osaka, Japan.
Appl Environ Microbiol. 2019 Mar 6;85(6). doi: 10.1128/AEM.02796-18. Print 2019 Mar 15.
Atypical enteropathogenic (aEPEC) strains (36 Japanese and 50 Bangladeshi) obtained from 649 poultry fecal samples were analyzed by molecular epidemiological methods. Clermont's phylogenetic typing showed that group A was more prevalent (58%, 50/86) than B1 (31%, 27/86). Intimin type β1, which is prevalent among human diarrheal patients, was predominant in both phylogroups B1 (81%, 22/27) and A (70%, 35/50). However, about 95% of B1-β1 strains belonged to virulence group I, and 77% of them were Japanese strains, while 17% (6/35) of A-β1 strains did. Multilocus variable-number tandem-repeat analysis (MLVA) distributed the strains into 52 distinct profiles, with Simpson's index of diversity (D) at 73%. When the data were combined with those of 142 previous strains from different sources, the minimum spanning tree formed five zones for porcine strains, poultry strains (excluding B1-β1), strains from healthy humans, bovine and human patient strains, and the B1-β1 poultry strains. Antimicrobial resistance to nalidixic acid was most common (74%) among the isolates. Sixty-eight percent of them demonstrated resistance to ≥3 antimicrobial agents, and most of them (91%) were from Bangladesh. The strains were assigned into two groups by hierarchical clustering. Correlation matrix analysis revealed that the virulence genes were negatively associated with antimicrobial resistance. The present study suggested that poultry, particularly Japanese poultry, could be another reservoir of aEPEC (phylogroup B1, virulence group I, and intimin type β1); however, poultry strains seem to be apart from patient strains that were closer to bovine strains. Bangladeshi aEPEC may be less virulent for humans but more resistant to antibiotics. Atypical enteropathogenic (aEPEC) is a diarrheagenic type of , as it possesses the intimin gene () for attachment and effacement on epithelium. Since aEPEC is ubiquitous even in developed countries, we previously used molecular epidemiological methods to discriminate aEPEC as a human pathogen. The present study assessed poultry as another source of human diarrheagenic aEPEC. Poultry could be the source of aEPEC (phylogroup B1, virulence group I, and intimin type β1) found among patient strains in Japan. However, the minimum spanning tree (MST) suggested that the strains from Japanese poultry were far from Japanese patient strains compared with the distance between bovine and patient strains. Bangladeshi avian strains seemed to be less diarrheagenic but are hazardous as a source of drug resistance genes.
从 649 份禽粪样本中获得的 36 株日本和 50 株孟加拉 atypical enteropathogenic （aEPEC）菌株，采用分子流行病学方法进行分析。Clermont 的系统发育分型显示，A 群更为普遍（58%，50/86），B1 群为 31%（27/86）。在两个 B1 群（81%，22/27）和 A 群（70%，35/50）中普遍存在的肠侵袭性大肠杆菌β1 型，是主要的。然而，约 95%的 B1-β1 菌株属于毒力组 I，其中 77%来自日本菌株，而 A-β1 菌株仅占 17%（6/35）。多位点可变数量串联重复分析（MLVA）将菌株分为 52 个不同的谱型，多样性指数（D）为 73%。当将数据与来自不同来源的 142 株先前菌株的数据相结合时，最小生成树为猪源菌株、禽源菌株（不包括 B1-β1）、健康人群源菌株、牛源和人源患者源菌株以及 B1-β1 禽源菌株形成了五个区。分离株对萘啶酸的耐药性最为常见（74%）。其中 68%的菌株对≥3 种抗菌药物表现出耐药性，其中大部分（91%）来自孟加拉国。这些菌株通过层次聚类分为两组。相关矩阵分析表明，毒力基因与抗菌药物耐药性呈负相关。本研究表明，禽，特别是日本禽，可能是另一种 aEPEC（B1 群、毒力组 I 和肠侵袭性大肠杆菌β1 型）的储存库；然而，禽源菌株似乎与更接近牛源菌株的患者源菌株不同。孟加拉国的 aEPEC 对人类的毒力可能较低，但对抗生素的耐药性较高。Atypical enteropathogenic （aEPEC）是一种致腹泻型，因为它具有附着和破坏上皮的肠侵袭性大肠杆菌基因（）。由于 aEPEC 在发达国家也很普遍，我们之前使用分子流行病学方法将 aEPEC 鉴定为人类病原体。本研究评估了禽作为人类腹泻性 aEPEC 的另一个来源。在日本，患者株中发现的禽源 aEPEC（B1 群、毒力组 I 和肠侵袭性大肠杆菌β1 型）可能来自禽源。然而，最小生成树（MST）表明，与牛源和患者源菌株之间的距离相比，来自日本禽的菌株与日本患者源菌株的距离较远。孟加拉国的禽源菌株似乎毒力较低，但作为耐药基因的来源存在危险。
