High prevalence of extended-spectrum and plasmidic AmpC beta- lactamase-producing Escherichia coli from poultry in Tunisia Elaa Maamar a , Samia Hammami a,d , Carla Andrea Alonso c , Nouha Dakhli a , Mohamed Salah Abbassi a,e , Sana Ferjani a , Zaineb Hamzaoui a , Mabrouka Saidani a,b , Carmen Torres c, ⁎, Ilhem Boutiba-Ben Boubaker a,b a University of Tunis El Manar, Faculty of Medicine of Tunis-Research Laboratory «Antimicrobial resistance», Tunis, Tunisia b Charles Nicolle Hospital, Laboratory of Microbiology, Tunis, Tunisia c Universidad de La Rioja, Area de Bioquímica y Biología Molecular, Logroño, Spain d University of Gafsa, Faculty of Sciences of Gafsa, Tunisia e University of Tunis El Manar, Institute of Veterinary Research of Tunisia-Laboratory of bacteriological research, Tunis, Tunisia abstract article info Article history: Received 16 December 2015 Received in revised form 29 April 2016 Accepted 2 May 2016 Available online 3 May 2016 This study was conducted to detect extended spectrum beta-lactamases (ESBLs) and plasmidic AmpC beta- lactamase (pAmpC-BL)-producing Escherichia coli isolates in industrial poultry samples were collected from healthy chickens of the three farms. Samples were inoculated onto desoxycholate-lactose-agar plates supple- mented with cefotaxime (2 mg/L). E. coli was identified by biochemical and molecular methods and antibiotic susceptibility testing by the disk diffusion method. Genes encoding ESBLs and pAmpC-BL were detected by PCR and sequencing. Phylogenetic groups were determined by triplex PCR. The molecular typing of strains was done by pulsed field gel electrophoresis (PFGE) and Multilocus Sequence Typing (MLST) in those isolates show- ing different PFGE patterns. Cefotaxime-resistant E. coli isolates were recovered in 48 of 137 fecal samples (35%), and one isolate/sample was further studied. The following beta-lactamase genes were detected: bla CTX-M-1 (29 isolates, isolated in all three farms), bla CTX-M-15 (5 isolates, confined in farm II), bla CTX-M-14 and bla CMY-2 (one iso- late and 13 isolates, respectively, in farm III). The 48 cefotaxime-resistant isolates were distributed into phylogroups: B1 (n = 21), A (n = 15) and D (n = 12). PFGE analysis revealed 19 unrelated patterns: 15 different profiles among ESBL-positive strains and 4 among the CMY-2-positive isolates. The following sequence types- associated phylogroups were detected: a) CTX-M-1-positive strains: lineages ST542-B1, ST212-B1, ST58-B1, ST155-B1 and ST349-D; b) CTX-M-15-positive strain: lineage ST405-D; c) CTX-M-14-positive strain: lineage ST1056-B1; d) CMY-2-positive strains: lineages ST117-D, ST2197-A, and ST155-B1. Healthy chickens constitute an important reservoir of ESBL- and pAmpC-BL-producing E. coli isolates that potentially could be transmitted to humans via the food chain or by direct contact. © 2016 Elsevier B.V. All rights reserved. Keywords: Fecal carriage CMY-2 CTX-M-1 Plasmids 1. Introduction A steady increase in the rates of Escherichia coli resistant to third gen- eration cephalosporins (3rd GC) is reported worldwide (Carattoli, 2008). This resistance can be associated with the production of ex- tended spectrum beta-lactamases (ESBLs) and/or plasmidic AmpC beta-lactamases (pAmpC-BL) (Paterson and Bonomo, 2005). Such resis- tant bacteria can cause severe community or hospital acquired infec- tions. Although person-to-person spread is recognized as the main way of spread of ESBL/pAmpC-BL containing E. coli both in hospitals and the community, the primary reservoirs of such organisms are con- tentious. Also, these microorganisms have been isolated from food- producing animals and derived foods in many countries, which has raised questions about the possible role of animal and food related res- ervoirs on this phenomenon (Mellata, 2013).The predominant ESBL families are CTX-M, TEM, and SHV (Paterson and Bonomo, 2005). The most common ESBL gene is bla CTX-M-1 and bla CTX-M-15 in animals and in humans, respectively, and the most common pAmpC-BL gene is bla CMY-2 (Ben Slama et al., 2011; Ben Sallem et al., 2012). ESBL/ pAmpC-BL transmission is mainly driven by mobile genetic elements, some of which are homologous in isolates from both food-producing animals and humans (Liébana et al., 2013). Epidemic plasmids belong- ing to the Inc groups F, A/C, N, HI2, I1 and K, carrying particular ESBL or pAmpC-BL encoding genes have been detected among farms and companion animals, food products and humans (Carattoli, 2008; Ben Sallem et al., 2014). In Tunisia, only a few studies report the fecal car- riage of E. coli resistant to 3rd GC in food-producing animals (Ben Sallem et al., 2012; Grami et al., 2013; Kilani et al., 2015). The present study was conducted to detect ESBL/pAmpC-BL positive E. coli isolates from healthy poultry in three Tunisian farms and to International Journal of Food Microbiology 231 (2016) 69–75 ⁎ Corresponding author at: Área de Bioquímica y Biología Molecular, Universidad de La Rioja Madre de Dios, 51, 26006 Logroño, Spain. E-mail address: carmen.torres@unirioja.es (C. Torres). http://dx.doi.org/10.1016/j.ijfoodmicro.2016.05.001 0168-1605/© 2016 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect International Journal of Food Microbiology journal homepage: www.elsevier.com/locate/ijfoodmicro