title: Detection of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in vegetables, soil and water of the farm environment in Tunisia.
abstract: One-hundred-nine samples of 18 different farms (49 of food-vegetables, 41 of soil and 19 of irrigation water) and 45 vegetable food samples of 13 markets were collected in Tunisia. These samples were inoculated in MacConkey agar plates supplemented with cefotaxime (2 μg/ml). ESBL-producing Enterobacteriaceae (ESBL-Eb) were detected in 10 of the 109 farm samples (vegetables, 8.2%; soil, 7.3%; water, 15.8%), and in 4 of 45 vegetables of markets (8.9%), recovering 15 ESBL-Eb. Isolates and ESBL genes detected were: Escherichia coli (n=8: 5 blaCTX-M-1, 2 blaCTX-M-15 and one blaCTX-M-14), Citrobacter freundii (n=4: 3 blaCTX-M-15 and one blaSHV-12), Enterobacter hormaechei (n=2: 2 blaCTX-M-15) and Klebsiella pneumoniae (n=1, blaCTX-M-15). The ISEcp1 sequence was found upstream of blaCTX-M genes in 13 of 14 strains (in three cases truncated by IS5), and orf477 or IS903 downstream. Class 1 integrons were detected in five strains and contained two gene cassette arrangements (dfrA17-aadA5 and aadA1). Most isolates tested showed a multiresistant phenotype. All blaCTX-M-15-positive strains carried the aac(6')-1b-cr gene, that affects to amikacin-tobramycin-kanamycin-ciprofloxacin. Five ESBL-Eb strains carried genes of the qnr family. The 8 ESBL-positive E. coli isolates were typed as: ST58/B1 (n=3) and ST117/D, ST131/B2, ST10/A, ST23/A, and the new ST3496/D (one strain, each). From 1-2 plasmids were detected in all ESBL-positive E. coli isolates (63-179 kb). The ESBL genes were transferred by conjugation in 4 blaCTX-M-1-positive E. coli strains, and transconjugants acquired a 97 kb IncI1 plasmid. ESBL-Eb isolates are frequently disseminated in vegetable farms and potentially could be transmitted to humans through the food chain.
authors: Laboratoire des Microorganismes et Biomolécules actives, Faculté de Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia.
authors: Leila
authors: L
authors: Ben Said
authors: Laboratory of Epidemiology and Veterinary Microbiology, Pasteur Institute of Tunis, Tunisia.
authors: Ahlem
authors: A
authors: Jouini
authors: Laboratoire des Microorganismes et Biomolécules actives, Faculté de Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia.
authors: Naouel
authors: N
authors: Klibi
authors: Laboratoire des Microorganismes et Biomolécules actives, Faculté de Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia.
authors: Raoudha
authors: R
authors: Dziri
authors: Area de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain.
authors: Carla Andrea
authors: CA
authors: Alonso
authors: Laboratoire des Microorganismes et Biomolécules actives, Faculté de Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia.
authors: Abdellatif
authors: A
authors: Boudabous
authors: Laboratoire des Microorganismes et Biomolécules actives, Faculté de Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia; Institut Supérieur des Sciences Biologiques Appliquées de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia.
authors: Karim
authors: K
authors: Ben Slama
authors: Area de Bioquímica y Biología Molecular, Universidad de La Rioja, 26006 Logroño, Spain. Electronic address: carmen.torres@unirioja.es.
authors: Carmen
authors: C
authors: Torres
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D032023:Integrons / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012988:Soil Microbiology; D014416:Tunisia; D014675:Vegetables / Q000382:microbiology*; D014871:Water Microbiology; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases
keywords: E. coli; ESBL; Enterobacteriaceae; Soil; Vegetables; Water