title: Serotype epidemiology and multidrug resistance patterns of Salmonella enterica infecting humans in Italy.
abstract: BACKGROUND
  Salmonella enterica is the zoonotic agent most frequently responsible for foodborne infections in humans worldwide. In this work the presence of S. enterica was investigated in 734 unique enteropathogenic isolates collected from human patients between 2011 and 2012.
  
  
  RESULTS
  All Salmonella spp. isolates were subjected to serotyping and antimicrobial susceptibility testing. Isolates displaying phenotypes and antimicrobial susceptibility profiles different from the reference strains were genotipically characterized. Several plasmid-embedded resistance determinants were identified and characterized. Non-typhoidal serotypes were most frequently diagnosed; monophasic Salmonella typhimurium 1,4 [5],12:i- and S. typhimurium represented the most prevalent serovars. Five isolates displayed phenotypes with extremely reduced susceptibility to antimicrobials: we detected multidrug resistance elements belonging to Ambler class A and class C in two non-typhoidal S. enterica serovars, i.e. Rissen and monophasic S. typhimurium 1,4 [5],12:i-, and in one typhoidal serovar, i.e., Paratyphi B. These resistance determinants have been so far almost exclusively associated with non-Salmonella members of the Enterobacteriaceae family. Alarmingly, two colistin resistant Salmonella enteritidis were also found.
  
  
  CONCLUSIONS
  This work draws the attention to the still low, but rising, percentage of multidrug resistant Salmonella isolates infecting humans in Italy. Our results suggest that prompt monitoring of Salmonella serovar dissemination and resistance to antimicrobials is highly required.
authors.affiliation: Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121 Padua, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Frasson
authors.affiliation: Microbiology and Virology Unit, Padua Teaching Hospital, via Giustiniani 2, 35121 Padua, Italy.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Bettanello
authors.affiliation: Microbiology and Virology Unit, Padua Teaching Hospital, via Giustiniani 2, 35121 Padua, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: De Canale
authors.affiliation: Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121 Padua, Italy ; Microbiology and Virology Unit, Padua Teaching Hospital, via Giustiniani 2, 35121 Padua, Italy.
authors.forename: Sara N
authors.initials: SN
authors.lastname: Richter
authors.affiliation: Department of Molecular Medicine, University of Padua, via Gabelli 63, 35121 Padua, Italy ; Microbiology and Virology Unit, Padua Teaching Hospital, via Giustiniani 2, 35121 Padua, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Palù
keywords: Epidemiology; Humans; Multidrug resistance; Salmonella