Analysis of blaSHV-12-carrying Escherichia coli clones and plasmids from human, animal and food sources.
This study aimed at characterizing 23 Escherichia coli isolates from various sources and their respective bla SHV-12 -carrying plasmids and sequencing one of these plasmids completely.



Isolates were typed by XbaI-PFGE, MLST and PCR-based phylotyping. Transformed bla SHV-12 -carrying plasmids were examined by replicon typing, S1-nuclease, conjugation, EcoRI-HindIII-BamHI digests and plasmid MLST. Co-located resistance genes and integrons as well as the bla SHV-12 genetic environment were analysed by PCR and sequencing. One IncI1 plasmid was sequenced completely using HiSeq 2500 and gap closure by PCRs and Sanger sequencing.



Among the 23 SHV-12-positive E. coli , some isolates from different sources showed the same characteristics: ST23/phylogroup A (human, dog, livestock), ST57/D (wild bird, chicken meat) and ST117/D (chicken meat, chicken). All bla SHV-12 genes were horizontally transferable via 30-120 kb plasmids of incompatibility groups IncI1 ( n  = 17), IncK ( n  = 3), IncF ( n  = 1), IncX3 ( n  = 1) and a non-typeable plasmid. IncK plasmids, indistinguishable in size and restriction patterns, were found in isolates from different sources (ST57/D, meat; ST131/B2, meat; ST57/B1, dog). The IncI1- bla SHV-12 -carrying plasmids were mostly assigned to plasmid ST (pST) 26 and pST3. Three plasmids showed novel pSTs (pST214, pST215). The majority of the IncI1 transformants exhibited resistance to β-lactams, chloramphenicol and streptomycin (in relation with a class 1 integron containing an estX - psp - aadA2 - cmlA1 - aadA1 - qacI gene cassette array), and to tetracycline. A novel bla SHV-12 environment was detected and whole plasmid sequencing revealed a Tn 21 -derived- bla SHV12 -ΔTn 1721 resistance complex.



Results from this study suggest that the dissemination of bla SHV-12 genes occurs by vertical (clonal) and horizontal transfer, the latter mainly mediated through IncI1 multidrug-resistance plasmids.
Department of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Carla Andrea
CA
Alonso
Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.|Department of Veterinary Medicine, Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Berlin, Germany.
Geovana Brenner
GB
Michael
Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.|College of Veterinary Medicine, China Agricultural University, Beijing, China.
Jun
J
Li
Department of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Sergio
S
Somalo
Faculty of Veterinary Science, University of Zaragoza, Zaragoza, Spain.
Carmen
C
Simón
College of Veterinary Medicine, China Agricultural University, Beijing, China.
Yang
Y
Wang
Federal Office of Consumer Protection and Food Safety (BVL), Berlin, Germany.
Heike
H
Kaspar
Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.
Kristina
K
Kadlec
Department of Biochemistry and Molecular Biology, University of La Rioja, Logroño, Spain.
Carmen
C
Torres
Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut (FLI), Neustadt-Mariensee, Germany.|Department of Veterinary Medicine, Institute of Microbiology and Epizootics, Centre of Infection Medicine, Freie Universität Berlin, Berlin, Germany.
Stefan
S
Schwarz
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002645:Chickens / Q000382:microbiology; D002701:Chloramphenicol / Q000494:pharmacology; D004285:Dogs / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D005516:Food Microbiology; D022761:Gene Transfer, Horizontal; D019450:Genes, MDR; D006801:Humans; D032023:Integrons; D008460:Meat / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000302:isolation & purification; D012093:Replicon; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics*
D000900:Anti-Bacterial Agents; D002701:Chloramphenicol; D001618:beta-Lactamases