Prevalence and characterization of extended-spectrum β-lactamase-producing Enterobacteriaceae in food-producing animals in Northern Italy.
The aim of this study was to assess the production of extended spectrum beta-lactamases (ESBL) in 56 strains of Enterobacteriaceae, obtained from 100 rectal swabs of farm animals, and to evaluate the horizontal transfer ca- pacity of the genetic determinants of resistance. The ESBL-positive strains were confirmed by phenotypic testing, confirmed by PCR and DNA sequence analysis. The localization of beta-lactamase genes was established by conju- gation experiments. Of the 56 analyzed strains, 20 (36%) resulted positive for ESBL production by the double-disk synergy test, and belonged to Escherichia coli 15 (75%) and Klebsiella ozaenae 5 (25%) species. Molecular analysis showed that all ESBL-producing isolates possessed genes encoding for TEM-type enzymes and/or CTX-M. The conjugation assays yielded positive results, thus denoting a plasmidic localization of the genes. This study high- lights the high percentage of ESBL-positive Enterobacteriaceae and the mobility of the responsible genes. Gene mo- bility implies highly negative consequences in terms of drug therapy because of the spread of antibiotic resistance.
Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy.
Sara
S
Stefani
Ilaria
I
Giovanelli
Immacolata
I
Anacarso
Carla
C
Condò
Patrizia
P
Messi
Simona
S
de Niederhäusern
Moreno
M
Bondi
Ramona
R
Iseppi
Carla
C
Sabia
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002417:Cattle / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D007558:Italy; D013552:Swine / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases