Search

Twenty-four Salmonella enterica isolates (13 serovar Enteritidis and 11 Typhimurium) isolated from 5,600 samples from intensive laying hen farms in Italy in 1998-2007 were characterized for antimicrobial resistance genes, pulsotype and phage type. Most of S. Typhimurium strains were pulsotype STYMXB.0147 (81.8%), phage type DT143 and resistant to sulfamethoxazole encoded by sul2. Two multidrug resistant (MDR) strains were identified. One strain, STYMXB.0061, was resistant to ampicillin (A), chloramphenicol (C), streptomycin (S), sulfamethoxazole (Su) and tetracycline (T) encoded by the Salmonella Genomic Island SGI1. The second MDR strain, STYMXB.0110, was resistant to SSuT encoded by sul1 and sul2, aadA1 and tet(C)-flanked by an IS26 element, respectively. The tet(C) gene has been reported to confer low levels of resistance and it has very rarely been detected in S. Typhimurium from poultry. In the current study, the MIC value (32 µg/mL) was consistent with the breakpoint (≥16 µg/mL) reported for Enterobacteriaceae. Most of the S. Enteritidis strains were resistant to Su (encoded by sul2). One MDR strain (ANxSSuT) was identified. With the exception of nalidixic acid (Nx), the resistances were respectively encoded by bla(TEM), strAB, sul2 and tet(A) harbored by an IncN conjugative plasmid. All isolates were pulsotype SENTXB.0001 with PT14b being the most prevalent identified phage type (57.1%). In Europe, SENTXB.0001 is the predominant PFGE profile from clinical cases and the identification of PT14b has steadily been on the increase since 2001. The findings presented in this study highlight the potential spread of S. Enteritidis phage types PT14b and S. Typhimurium DT143 in a field of particular relevance for zoonoses. Additional, the presence of resistance genes and genetic elements (conjugative plasmid and IS element) underlines the need to assess routinely studies in field, such as poultry farms, relevant fot the public health and suitable for the storage and diffusion of antimicrobial resistance.

The epidemiology of salmonellosis in Italy has clearly changed over the years. The circulation of human-specific genotypes has diminished while there has been an increase in genotypes of animal origin. In the years 1994-2009, 3727 Salmonella genotypes were isolated and/or genotyped in Sardinia (Italy). The most frequent serotypes were Salmonella Enteritidis (29%) and Salmonella Typhimurium (25,7%). If we consider the years 2000-2009, 6.4% of isolated genotypes were found to be Salmonellae with the serologic profile 4,5,12:i:-, 35.8% of which were multiresistant. Molecular analyses have shown a correlation between Salmonellae 4,5,12:i:- and Salmonellae Typhimurium DT104. Further studies will be conducted to evaluate the link with other Salmonella variants with a similar serologic profile.

In the last two decades, the emergence and spread of antimicrobial-resistant pathogens, among them Salmonella, has become a serious health hazard worldwide, and specifically the high incidence of multidrug resistance has been encountered widely in many European countries. This study examines the antimicrobial susceptibility of Salmonella enterica strains Typhimurium and Enteritidis isolated in Campania and Calabria region (Southern Italy) from animal and food of animal origin. The relationship of antibiotic resistance phenotype and the presence of some resistance genes has been also investigated. As expected, our results show that resistance to ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracycline is common, although resistance to other antibiotics (i.e.: nalidixic acid) and other resistance patterns occur. The genetic resistant patterns have been partially described for this food-borne pathogen but efforts are needed to realize the complete characterization of antimicrobial resistance genes.

From 1992 to 1997, only six sporadic isolates of Salmonella enterica serotype Enteritidis from patients with cases of gastroenteritis in southern Italy exhibited resistance to broad-spectrum cephalosporins. Five isolates produced SHV-12, and one isolate encoded a class C beta-lactamase. The bla(SHV-12) gene was located in at least two different self-transferable plasmids, one of which also carried a novel class 1 integron.

Background: The role of antibiotic therapy on Salmonella faecal excretion is controversial. Acute Salmonella gastroenteritis induces long-lasting digestive symptoms in up to one-third of subjects. The role of antimicrobial therapy on persistent post-infectious symptoms is unknown., Aim: To investigate the role of antibiotic therapy on long-term germ faecal excretion and digestive symptoms after Salmonella infection., Subjects and Methods: 1543 subjects [518 aged between 3 and 5 years (35.3%); 950 between 6 and 10 years (64.7%) and 75 adults (4.9%)] involved in a single outbreak of Salmonella enteritis fulfilled the study criteria by repeating stool cultures and answering a symptom questionnaire 3 months post-infection., Results: 327 subjects (21.2%) were treated with antibiotics during the acute infection [121 children aged 3-5 years (23.4%), 175 children aged 6-10 years (18.4%) and 31 adults (41.3%)]. Antibiotic treatment did not affect Salmonella excretion at any of the time points studied up to three months post-infection in any age group as compared to age-matched untreated controls. Persistent digestive symptoms were more common among the patients treated with antibiotics (9.5% vs. 2.9%; P=0.003)., Conclusions: Antibiotic therapy does not affect Salmonella enteritis excretion. Digestive symptoms after clearance of the infectious agent are significantly higher in patients treated with antibiotics during acute gastroenteritis.

The survival of fecal coliforms, fecal streptococci, Salmonella enteritidis and Staphylococcus aureus in sea water (35@1000 salinity) in the dark and at room temperature was evaluated. Staphylococcus aureus has been regarded for a long time as the new parameter to add to the classic ones in order to define the quality and suitability to recreational use. At the sperimental condition considered the survival of fecal coliforms, fecal streptococci, Salmonella enteritidis, and Staphylococcus aureus resulted equal to 48 h, 88 h, 56 h, and 96 h respectively. Fecal coliforms resulted the most sensitive bacteria to osmotic shock while Staphylococcus aureus the most adaptable species. Our results seem to indicate the opportunity of reconsidering the microbiological parameters used for the control of beach water.

During 1990 to 1998, we identified multidrug-resistant isolates of Salmonella Enteritidis in southern Italy. Plasmids containing class I integrons and codifying for synthesis of extended- spectrum beta-lactamases were detected. Active surveillance for resistance to antimicrobial agents is needed to guard against the possible spread of resistant clones.

During the period 1982-1992 the percentages of Salmonella enteritidis isolations in Italy have increased from 2.4 to 57.1% from human beings and from 0.5 to 22.8% from food. Seven hundred and fifty-seven isolates, 702 from man and 55 from food, were characterized. Phage type 4 accounted for the 76.8% of these isolates. The majority of strains were sensitive to the antibiotics tested; only 18 (2.4%) showed resistance to three or more antibiotics by nine different patterns.