RESUMEN
This study was undertaken to discern the differences of the multi-locus sequence typing (MLST), O serogroups, and virulence factors among 34 CTX-M-1 Escherichia coli, 49 CTX-M-9 strains and 23 non-CTX-M isolates from chickens in Henan province, China. The MLST scheme yielded 34 sequence types, in which ST155 and ST359 were frequent (17% and 15%, respectively) and associated with zoonotic disease. The irp-2 (20% versus 2%, P = 0.0001), traT (85.3% versus 56.5%, P = 0.019), and sfaS (70.6% versus 0, P = 0.021) were significantly more prevalent in CTX-M-1 E. coli than in non-CTX-M producers. Also, CTX-M-9 isolates carried more irp-2 (17% versus 2%, P = 0.023), iroN (71.4% versus 39.1%, P = 0.019), and iss (79.6% versus 39.1%, P = 0.002) genes. In conclusion, although the 106 isolates encompassed a great genetic diversity, the CTX-M isolates harbored more virulence factor genes than non-CTX-M producers.
Asunto(s)
Pollos , Infecciones por Escherichia coli/veterinaria , Proteínas de Escherichia coli/análisis , Escherichia coli/genética , Variación Genética , Enfermedades de las Aves de Corral/epidemiología , Factores de Virulencia/genética , beta-Lactamasas/análisis , Pruebas de Aglutinación/veterinaria , Animales , China/epidemiología , Escherichia coli/fisiología , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Tipificación de Secuencias Multilocus/veterinaria , Enfermedades de las Aves de Corral/microbiología , Prevalencia , SerogrupoRESUMEN
A 139,622-bp IncI1 ST71 conjugative plasmid pEC012 from an avian Escherichia coli D-ST117 strain was sequenced, which carried five IS26-bracketed resistance modules: IS26-fosA3-orf1-orf2-Δorf3-IS26, IS26-fip-ΔISEcp1-bla CTX-M-65-IS903D-iroN-IS26, IS26-ΔtnpR-bla TEM-1-rmtB-IS26, IS26-oqxAB-IS26, and IS26-floR-aac(3)-IV-IS26. The backbone of pEC012 was similar to that of several other IncI1 ST71 plasmids: pV408, pM105, and pC271, but these plasmids had different arrangements of multidrug resistance region. In addition, the novel ISEc57 element was identified, which is in the IS21 family. The stepwise emergence of multi-resistance regions demonstrated the accumulation of different resistance determinants through homologous recombination. To the best of our knowledge, this is the first study to identify a multidrug-resistant IncI1 ST71 plasmid carrying bla CTX-M-65, rmtB, fosA3, floR, and oqxAB in an avian E. coli ST117 strain.