Serotype epidemiology and multidrug resistance patterns of Salmonella enterica infecting humans in Italy.

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.

Multilocus sequence typing of Campylobacter jejuni and Campylobacter coli from humans and chickens in North-Eastern Italy.

This paper reports the multilocus sequence typing (MLST) of 57 C. jejuni and C. coli isolates from humans and chickens in Italy and the identification of 17 new sequence types (STs). A high genetic diversity was detected among C. jejuni/C. coli and human/chicken isolates, with a predominance of clonal complexes CC21 and CC828. Although human STs were not the same as those found in chickens, 3 CCs overlapped between human and chicken isolates. Genotyping of Campylobacter strains by MLST should be encouraged in order to implement surveillance and con- trol of infection in humans and in animal reservoirs in Italy.