Comparative study of all Salmonella enterica serovar Enteritidis strains isolated from food and food animals in Greece from 2008 to 2010 with clinical isolates.

The aim of the present work was to study the epidemiology of Salmonella enterica serovar Enteritidis (S. Enteritidis) in Greece, comparing all the food and food animal isolates during a 3-year period with clinical isolates. Submission of the generated data to the PulseNet Europe database was carried out in order to study the population structure of this particular serovar and indicate possible connections with European strains. One hundred and sixty-eight (168) S. Enteritidis strains of human, animal, and food origin, isolated during the period 2008-2010 in Greece, were studied. Strains were characterized by phenotypic (antibiotic resistance) and molecular [pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST)] methods. PFGE revealed 39 XbaI, 48 BlnI, and 80 XbaI-BlnI distinct pulsotypes, suggesting several clones circulating through the food chain and multiple sources of transmission. Submission to the PulseNet Europe database indicated that PFGE profile SENTXB.0001, the most common PFGE profile in Europe, was also predominant in Greece (33.3 %). MLST showed that all the strains studied shared the same sequence type (ST11), representing the most common ST in Europe. High rates of resistance to nalidixic acid were observed among human and poultry isolates (~25 %), indicating the potential fluoroquinolone treatment failure. Our data suggest that strains originating from multiple reservoirs circulated in Greece through the food chain during the study period. Predominant profiles in Greece were common to PulseNet Europe profiles, indicating similarities between the S. Enteritidis populations in Greece and Europe.

Phenotypic and molecular characterisation of multiresistant monophasic Salmonella Typhimurium (1,4,[5],12:i:-) in Greece, 2006 to 2011.

Recently, multiresistant Salmonella enterica serovar1,4,[5],12:i:-, a monophasic variant of S. Typhimurium(1,4,[5],12:i:1,2) emerged, and is now among the most common serovars isolated from humans in many countries.In Greece, monophasic Typhimurium which was recorded for the first time in human isolates in 2007(0.3% of total isolates), increased sharply thereafter,and since 2009 is the third most frequent serovar. In the present study, 119 S. enterica 1,4,[5],12:i:- strains of human, animal and food origin, isolated during the period between 2006 and 2011, were examined.Strains verified as monophasic Typhimurium variants by polymerase chain reaction (PCR) (97 strains), were further characterised by phenotypic (antibiotic resistance and phage typing) and molecular (pulsed-field gel electrophoresis ­ PFGE) methods. The results indicate that multiple clones of multiresistant monophasic Typhimurium are circulating in Greece. The most frequently encountered clone in humans and pigs was that of phage type DT120, R-type ASSuTSpTm and PFGEprofile STYMXB.0010, while in poultry other clones were detected. The data indicate that pigs may be a reservoir of this clone in Greece.

Phenotypic and molecular characterization of multidrug-resistant Salmonella enterica serovar Hadar in Greece, from 2007 to 2010.

All 120 strains of Salmonella enterica serovar Hadar isolated during 2007-2010 in Greece were characterized by phenotypic and molecular methods. High rates of resistance to nalidixic acid (92%) and low levels of ciprofloxacin resistance (88%) were observed. Pulsenet-pulsed field gel electrophoresis profile SHADXB.0001 was predominant in Greece (58%) as in Europe but PT1, a rare phage type in Europe, was frequent in Greece (56%). The SHADXB.0001 and PT1 clone (38%) were found in humans, animals and food of animal origin with R-type ApSpTNxpCp being predominant (25%). The data indicate that this clone (possibly endemic) was circulating through the food chain in Greece during the study period.