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Insight into the molecular characteristics of new multiresistant clones and plasmids in Salmonella Infantis in poultry and man

Szmolka, Ama and Szabó, Mónika and Nagy, Tibor and Pászti, Judit and Nógrády, Noémi and Adrián, Erzsébet and Olasz, Ferenc and Nagy, Béla (2015) Insight into the molecular characteristics of new multiresistant clones and plasmids in Salmonella Infantis in poultry and man. In: 17th International Congress of the Hungarian Society for Microbiology, July 8-10, 2015, Budapest.

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Abstract

The lack of the regular monitoring of Salmonella Infantis together with the effort to reduce prevalence of „top five” serovars lead to a dramatic increase of S. Infantis in poultry with reflection in human population. As a background of this study, a clonal change reported previously in Hungarian S. Infantis strains is remarkable (Nógrády et al., 2007). Accordingly, in the early 2000s, older pansensitive isolates of S. Infantis have been replaced by new tetraresistant clones carrying a large plasmid conferring the multiresistance phenotype. Based on the above finding, our aim is to characterize antimicrobial resistance pheno-and genotypes of recently isolated S. Infantis strains, and to provide the first description of the large multiresistance plasmid in a poultry isolate representing the prevalent tetraresistant Hungarian clone. For this purpose ~300 strains of S. Infantis were tested, originating mostly from broilers and from human clinical samples. Strains intended to represent the current status of S. Infantis infection in poultry and human between 2011-2013. The antimicrobial resistance phenotype, pulsotype and the plasmid content were determined, based on which representative strains were selected for resistance genotyping by PCR microarray. One poultry strain (SI 54/04), representative of the tetraresistant, plasmid containing strains was subjected to genome sequencing (Olasz et al., 2015), giving a basis for the characterization of the large multiresistance plasmid. Resistance phenotyping and PFGE analysis has shown a constant circulation of the former major multiresistant clones and patterns within the newly isolated strains of S. Infantis both in poultry and human. Multiresistance phenotypes were associated mostly with the presence of class 1 integrons (intI1)and the gene tetA for tetracycline resistance, being the prime genetic markers for the carriage of the large multiresistance plasmid. However, the coexistence of the tetA and other plasmid related genes for β-lactam and fluoroquinolone resistance such as blaTEM-1, bla CMY-9 or qnr indicate important and divergent plasmid associations in some of the strains. By sequence analysis we provide the characterization of the multiresistance megaplasmid (pSI54/04) of the strain SI 54/04 which can be considered as the first Hungarian reference plasmid of Salmonella Infantis. The backbone of this IncI type plasmid is a mosaic of resistance (nickel-, mercury resistance), and virulence regions (encoding siderophore Yersiniabactin, fimbriae) potentially promoting survival not only in the vertebrate hosts but also in their environment. Support of OTKA K101564 and the János Bolyai stipend of the Hungarian Academy of Sciences to A. Szmolka is acknowledged.

Item Type: Conference or Workshop Item (Lecture)
Subjects: Q Science / természettudomány > QR Microbiology / mikrobiológia
Depositing User: PhD Ama Szmolka
Date Deposited: 18 Sep 2015 11:26
Last Modified: 18 Sep 2015 11:26
URI: http://real.mtak.hu/id/eprint/26897

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