Comparative Analysis of Extended Spectrum Beta- Lactamase CTX-M-65-Producing Salmonella Infantis Isolates from Humans, Food Animals, and Retail Chickens in the United States [PublishAheadOfPrint]

We sequenced the genomes of ten Salmonella enterica serovar Infantis containing bla_CTX-M-65 isolated from chicken, cattle, and human sources collected between 2012 and 2015 in the United States through routine NARMS surveillance and product sampling programs. We also completely assembled the plasmids from four of the isolates. All isolates had a D87Y mutation in the gyrA gene and harbored between 7 and 10 resistance genes (aph (4)-Ia, aac (3)-IVa, aph(3' )-Ic, bla_CTX-M-65, fosA3, floR, dfrA14, sul1, tetA, aadA1) located in two distinct sites of a megaplasmid (~316-323kb) similar to that described in a bla_CTX-M-65-positive S. Infantis isolated from a patient in Italy. High-quality single nucleotide polymorphism (hqSNP) analysis revealed that all U.S. isolates were closely related, separated by only 1 to 38 pairwise high quality SNPs, indicating a high likelihood that strains from humans, chicken, and cattle recently evolved from a common ancestor. The U.S. isolates were genetically similar to the bla_CTX-M-65-positive S. Infantis isolate from Italy, with a separation of 34 to 47 SNPs. This is the first report of the bla_CTX-M-65 gene and the pESI-like megaplasmid from S. Infantis in the United States, and illustrates the importance of applying a global One Health, human and animal perspective to combat antimicrobial resistance.

http://ift.tt/2psWjVi