Avian industries have been reported as an important contributor in the worldwide spread of antibiotic resistance owing to some particular practices especially the overuse of antibiotics. Thus in this study, we aimed to characterize extended-spectrum-beta-lactamase (ESBL) and acquired-AmpC-beta-lactamase (aAmpC)-producing Escherichia coli isolates from chicken faeces and raw meat in Tunisia. During the year 2018, 286 faecal chicken swabs and 47 raw chicken meat samples were collected and processed to recover cefotaxime-resistant E. coli. Antimicrobial susceptibility was performed by disk-diffusion and/or broth-microdilution. bla_TEM, bla_SHV, bla_CTX-M, and bla_CMY genes were investigated by PCR/sequencing. Genes encoding resistance to colistin (mcr-1 to mcr-8), tetracycline (tetA/tetB), sulfonamide (sul1/sul3), and chloramphenicol (cmlA), were analysed by PCR. Class 1 integrons were investigated by PCR/sequencing. Phylogenetic groups of all isolates were determined. PFGE and MLST were performed for representative isolates. PCR-based replicon typing was performed in mcr1-harbouring isolates. Cefotaxime-resistant E. coli was detected in 22.4% (64/286) and 63.8% (30/47) of faeces and meat samples, respectively. Ninety isolates were ESBL-producers and harboured the genes: bla_CTX-M-1 +/− bla_TEM-1 (n = 65), bla_CTX-M-55 +/− bla_TEM-1 (n = 21), bla_CTX-M-14 (n = 1), and bla_SHV-12 (n = 3). The bla_CMY-2 gene was detected in four ESBL-negative isolates. Isolates belonged to phylogroups D (50%), A (36.2%), B1 (9.6%), and B2 (4.3%). Fifty-four were colistin-resistant and 52 carried the mcr-1 gene. The tetA, sul1/sul3 and cmlA genes were detected among resistant isolates and 76 harboured class 1 integrons. MLST analysis revealed 13 sequence types (STs). The isolates were classified into 28 PFGE types. The IncP, IncFIB, and IncI1 replicons were detected among mcr-1-positive strains. We report a high frequency of ESBL-producers and colistin-resistant E. coli in chicken and derived food and the detection for the first time of bla_CTX-M-55 in poultry in Tunisia.

据报道，由于某些特殊做法，尤其是抗生素的过度使用，禽类工业是导致抗生素耐药性在全球范围内传播的重要因素。因此，在这项研究中，我们旨在表征突尼斯鸡粪便和生肉中产生的广谱β-内酰胺酶（ESBL）和获得性AmpC-β-内酰胺酶（aAmpC）的大肠杆菌分离株。在2018年，收集并处理了286份粪便鸡拭子和47份生鸡肉样品，并进行了处理以回收耐头孢噻肟的大肠杆菌。通过圆盘扩散和/或肉汤微量稀释进行抗药性试验。bla _TEM，bla _SHV，bla _CTX-M和bla通过PCR /测序研究_CMY基因。通过PCR分析编码对大肠菌素（mcr -1至mcr -8），四环素（tet A / tet B），磺酰胺（sul 1 / sul 3）和氯霉素（cml A）的抗性的基因。通过PCR /测序研究了1类整合素。确定了所有分离株的系统发生组。对代表性分离株进行了PFGE和MLST。基于PCR的复制子分型在mcr 1-harbour分离株中进行。耐头孢噻肟的大肠杆菌在粪便和肉类样品中分别检出了22.4％（64/286）和63.8％（30/47）。90个分离物是ESBL的产生者并带有以下基因：bla _CTX-M-1 +/- bla _TEM-1（n  = 65），bla _CTX-M-55 +/- bla _TEM-1（n  = 21），bla _CTX-M-14（n  = 1）和bla _SHV-12（n  = 3）。所述BLA _CMY-2在4 ESBL阴性菌株中检测到的基因。分离株属于系统群D（50％），A（36.2％），B1（9.6％）和B2（4.3％）。有54种对大肠菌素具有抗药性，其中52种具有mcr -1基因。在TET A，sul1 / sul3和CML耐药株和76窝藏1类整合中检测到甲基因。MLST分析揭示了13种序列类型（ST）。分离株分为28种PFGE类型。该公司P，公司FIB，和公司之间进行检测I1复制子MCR -1阳性菌株。我们报告了在鸡和衍生食品中高频率的ESBL生产者和对大肠菌素耐药的大肠杆菌，以及在突尼斯的禽类中首次检测到bla _CTX-M-55。