Article Text
Abstract
Introduction Although there has been a decrease in the number of cases of salmonellosis in the European Union, it still represents the primary cause of foodborne outbreaks. In Calabria region, data are lacking for the incidence of human non-typhoid salmonellosis as active surveillance has never been carried out.
Objective To report the results of a laboratory and patient-based morbidity survey in Calabria to describe the incidence and distribution of Salmonella serovars isolated from humans, with a focus on antimicrobial resistance patterns.
Methods Positive cultures from human samples were collected from every laboratory participating in the surveillance, with a minimum set of information about each isolate. A questionnaire was then administered to the patients by telephone interview to assess the potential risk exposures.
Salmonella isolates underwent biochemical identification, molecular analysis by PCR and antimicrobial susceptibility testing by the disk-diffusion method.
Results During a 2-year period, 105 strains of Salmonella spp were isolated from samples of patients with diarrhoea, with the highest isolation rate for children aged 1–5 years. The standardised rate was 2.7 cases per 1 00 000 population. The most common Salmonella isolates belonged to monophasic variant of S. Typhimurium (S. 4,[5],12:i:-) (33.3%), followed by S. Typhimurium (21.9%). 30.5% of the isolates were susceptible to all microbial agents tested and the most common pan-susceptible serotype was S. Napoli (100%). S. 4,[5],12:i:- was resistant to ampicillin, streptomycin, sulfonamides and tetracyclines in 42.9% cases, while resistance to quinolones was seen in 14.3% of the isolates.
Conclusions The results provide evidence that an active surveillance system effectively enhances Salmonella notifications. The high prevalence of antimicrobial resistance, including resistance to quinolones and multiresistance, enforces the need to strengthen strategies of surveillance and monitoring of antimicrobial use.
- salmonella
- morbidity survey
- gastrointestinal infection
- antimicrobial
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Footnotes
Contributors VM contributed to the data analysis and its interpretation, and wrote the manuscript. MC made substantial contributions to the acquisition of the data, contributed to the data analysis and its interpretation. YTRP, MRC, FA, and PT participated in the acquisition of the data and contributed to the data analysis. CP and CG made substantial contributions to conception and design of the study, coordinated data collection, contributed to the data analysis and its interpretation, and revised the manuscript critically for important intellectual content. MP conceptualised and designed the study, supervised data collection, was responsible for the data analysis and interpretation and revised the manuscript. All authors had full access to all the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis.
Funding This work was supported by Italian Ministry of Health-Centro di Controllo delle Malattie ‘Risk assessment of zoonotic infections due to consumption of fresh produce grown in areas with high livestock density’-grant number CCM 2012/604.
Competing interests All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Patient consent The article does not contain personal medical information about an identifiable living individual.
Ethics approval Institutional ethical committee (‘Mater Domini’ Hospital of Catanzaro, Italy).
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Survey data were not included in the present article and are available from the authors.