检测从突尼斯野生鸟类中分离的携带 CTX-M-15 的大肠杆菌。
Detection of CTX-M-15 harboring Escherichia coli isolated from wild birds in Tunisia.
机构信息
Laboratoire des Microorganismes et Biomolécules actives, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092, Tunis, Tunisie.
Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université de Tunis El Manar, 2092, Tunis, Tunisie.
出版信息
BMC Microbiol. 2018 Apr 2;18(1):26. doi: 10.1186/s12866-018-1163-2.
BACKGROUND
The spreading of antibiotic resistant bacteria is becoming nowadays an alarming threat to human and animal health. There is increasing evidence showing that wild birds could significantly contribute to the transmission and spreading of drug-resistant bacteria. However, data for antimicrobial resistance in wild birds remain scarce, especially throughout Africa. The aims of this investigation were to analyze the prevalence of ESBL-producing E. coli in faecal samples of wild birds in Tunisia and to characterize the recovered isolates.
RESULTS
One hundred and eleven samples were inoculated on MacConkey agar plates supplemented with cefotaxime (2 μg/ml). ESBL-producing E. coli isolates were detected in 12 of 111 faecal samples (10.81%) and one isolate per sample was further characterized. β-lactamase detected genes were as follows: bla (8 isolates), bla + bla (4 isolates). The ISEcp1 and orf477 sequences were found respectively in the regions upstream and downstream of all bla genes. Seven different plasmid profiles were observed among the isolates. IncF (FII, FIA, FIB) and IncW replicons were identified in 11 CTX-M-15 producing isolates, and mostly, other replicons were also identified: IncHI2, IncA/C, IncP, IncI1 and IncX. All ESBL-producing E. coli isolates were integron positive and possessed "empty" integron structures with no inserted region of DNA. The following detected virulence genes were: (number of isolates in parentheses): fimA (ten); papC (seven); aer (five); eae (one); and papGIII, hly, cnf, and bfp (none). Molecular typing using pulsed-field gel electrophoresis and multilocus sequence typing showed a low genetic heterogeneity among the 12 ESBL-producing strains with five unrelated PFGE types and five different sequence types (STs) respectively. CTX-M-15-producing isolates were ascribed to phylogroup A (eleven isolates) and B2 (one isolate).
CONCLUSION
To our knowledge, this study provides the first insight into the contribution of wild birds to the dynamics of ESBL-producing E. coli in Tunisia.
背景
抗生素耐药菌的传播如今对人类和动物健康构成了严重威胁。越来越多的证据表明，野生鸟类可能在耐药菌的传播和扩散方面发挥了重要作用。然而，关于野生鸟类中抗生素耐药性的数据仍然很少，尤其是在非洲。本研究的目的是分析突尼斯野生鸟类粪便样本中产 ESBL 大肠杆菌的流行情况，并对分离株进行特征描述。
结果
将 111 个样本接种在含有头孢噻肟（2μg/ml）的 MacConkey 琼脂平板上。在 111 份粪便样本中检出 12 份（10.81%）产 ESBL 大肠杆菌，对每份样本的一个分离株进行了进一步鉴定。检测到的β-内酰胺酶基因如下：bla（8 株）、bla+bla（4 株）。所有 bla 基因上下游区域均发现 ISEcp1 和 orf477 序列。在分离株中观察到 7 种不同的质粒图谱。在 11 株 CTX-M-15 产生菌中鉴定出 IncF（FII、FIA、FIB）和 IncW 复制子，大多数情况下还鉴定出其他复制子：IncHI2、IncA/C、IncP、IncI1 和 IncX。所有产 ESBL 大肠杆菌分离株均为整合子阳性，具有无插入 DNA 的“空”整合子结构。检测到的毒力基因如下（括号中为分离株数）：fimA（10 株）、papC（7 株）、aer（5 株）、eae（1 株）和 papGIII、hly、cnf、bfp（均未检出）。脉冲场凝胶电泳和多位点序列分型的分子分型显示，12 株产 ESBL 株之间遗传异质性较低，分别有 5 种不同的 PFGE 型和 5 种不同的序列型（ST）。CTX-M-15 产生菌被归为 A 群（11 株）和 B2 群（1 株）。
结论
据我们所知，本研究首次揭示了野生鸟类对突尼斯产 ESBL 大肠杆菌动态的贡献。
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