Characterization of Salmonella Typhimurium and monophasic Salmonella Typhimurium isolated in Abruzzo and Molise regions, Italy, from 2012 to 2017

Salmonellosis is currently the second most common zoonosis in European Union but in the 6-years periods, between 2012 and 2017, there has been a significant decrease trend in the yearly number of infections caused by Salmonella. In Italy, S. Typhimurium and monophasic S. Typhimurium represent the most prevalent serotypes. In this paper, we investigated these two serovars isolated from 2012 to 2017 in Abruzzo and Molise regions. A set of 345 strains isolated from human sporadic cases, surface water, food and animals were collected and analyzed. Monophasic S. Typhimurium strains were found to be resistant to streptomycin, sulfisoxazole, ampicillin, tetracycline and nalidixic acid, while S. Typhimurium isolates showed high levels of resistance to tetracycline, sulfisoxazole and ampicillin. The 5-loci Multilocus Variable-Number Tandem Repeat Analysis (MLVA) identified 88 genotypes (GT), six of which were common for the two serovars. Several MLVA profiles were shared by human and non-human isolates. MLVA had sufficient typing resolution for epidemiological studies of S. Typhimurium but demonstrated poor discriminatory in trace-back study of monophasic S. Typhimurium.

Genomic Comparison of Salmonella Enteritidis Strains Isolated from Laying Hens and Humans in the Abruzzi Region during 2018

Salmonellosis is a major cause of bacterial foodborne infection. Since 2016, an increased number of cases of gastroenteritis caused by Salmonella enterica serovar Enteritidis linked to eggs produced in Poland has been reported in Europe. In Italy, S. Enteritidis is one of the three most commonly reported serotypes, associated mainly with the consumption of contaminated eggs and derived products. In our work, we analysed 61 strains of S. Enteritidis obtained from humans and farms in the Abruzzi region, Italy, in 2018. We used Multiple-Loci Variable-Number Tandem Repeat (VNTR) analysis (MLVA)-based typing and Whole-Genome Sequencing (WGS) tools to identify closely related strains and perform cluster analysis. We found two clusters of genetically similar strains. The first one was present in the local farms and isolated from human cases and had single-linkage distance of no more than two core genes and less than five Single-Nucleotide Polymorphisms (SNPs). The second cluster contained strains isolated from humans and from a dessert (tiramisù) sample that shared identical core genome and were assigned the same SNP address. Cluster 2 isolates were found to be genetically similar to an S. Enteritidis strain from a multi-country outbreak linked to Polish eggs.

Reproductive disorders in domestic canaries (Serinus canarius domesticus): a retrospective study on bacterial isolates and their antimicrobial resistance in Italy from 2009 to 2012

Reproductive disorders are responsible for significant economic losses in canary aviculture due to embryo and newborn chick mortality. Most of the time, deaths are caused by bacterial pathogens, however little published data exist about the prevalence of bacterial isolates that are identified during diagnostic protocols. This study reports on data collected from previous investigations carried out on cloacal swabs (n 456), unhatched eggs (n 52), and dead newborn chicks (n 68) collected from canary aviaries with a history of reproductive disorders. Of the examined samples, 41% were positive for the presence of pathogenic or potentially pathogenic bacteria, with particular regard to Gram negative species during bacteriological investigations. The most prevalent microorganisms were Gram-negative (55%). A predominance of Klebsiella, Escherichia, and Pantoea genera was observed. These are usually associated to pathological conditions in pet birds. Among Gram-positive bacteria, Bacillus spp. and Staphylococcus spp. were most prevalent. The antimicrobial susceptibility testing carried out on bacterial isolates showed a multiple resistance, especially against amoxycillin, erythromycin, spiramycin, tiamulin, and tylosin. This study represents a first attempt to provide an update on microbial causes of embryonic and neonatal mortality in canary aviaries in Italy; in addition, it provides further understandings about the efficacy of antimicrobial therapy.

Identification and characterization of Yersinia enterocolitica strains isolated from pig tonsils at slaughterhouse in Central Italy

Yersinia enterocolitica causes foodborne disease in humans and infections are usually acquired from contaminated raw or undercooked pork. Pigs are considered the primary reservoir of human pathogenic bio-serotypes. A total of 376 tonsil tissue samples collected after evisceration and cutting from pig carcasses were tested for Yersinia enterocolitica. Animals came from an abattoir located in the Abruzzo region, Italy. Yersinia enterocolitica was isolated from 35 out of 376 (9.31%) samples. A total of 47 strains were isolated, the prevalent bio-serotype was 4÷O:3 (95.74%), followed by bio-serotype 4÷O:9 (2.13%), and 3÷O:9 (2.13%). When characterized by DNA microarray, all strains clustered into 2 main groups. The bigger group was characterised by the presence of plasmid genes of the secretion apparatus as well as by the genes for the agellum transport machinery, while the smaller group was characterised only by genes for the agellum transport machinery. The high frequency of the pathogenic biotype 4÷O:3 able to infect humans and considered an emerging zoonotic pathogen con rms the role of pigs as natural reservoir. Since there is no official data on Yersinia enterocolitica, it is difficult to assess the implications of this food pathogen for public health. A monitoring program should be implemented for contamination in food in order to assess the risk for the consumer linked to raw or undercooked pork products.

Cases of human brucellosis in Sweden linked to Middle East and Africa

BACKGROUND

Human brucellosis cases are still reported each year in Sweden despite eradication of the disease in animals. Epidemiological investigation has never been conducted to trace back the source of human infection in the country. The purpose of the study was to identify the source of infection for 16 human brucellosis cases that occurred in Sweden, during the period 2008-2012.

RESULTS

The isolates were identified as Brucella melitensis and MLVA-16 genotyping revealed 14 different genotypes of East Mediterranean and Africa lineages. We also reported one case of laboratory-acquired brucellosis (LAB) that was shown to be epidemiological linked to one of the cases in the current study.

CONCLUSIONS

Brucella melitensis was the only species diagnosed, confirming its highest zoonotic potential in the genus Brucella, and MLVA-16 results demonstrated that the cases of brucellosis in Sweden herein investigated, are imported and linked to travel in the Middle East and Africa. Due to its zoonotic concerns, any acute febrile illness linked to recent travel within those regions should be investigated for brucellosis and samples should be processed according to biosafety level 3 regulations.

Polymerase chain reaction and bacteriological comparative analysis of raw milk samples and buffalo mozzarella produced and marketed in Caserta in the Campania region of Italy

To help identify an epidemiological link between the consumption of buffalo mozzarella prepared with raw milk (not heat-treated) and cases of human brucellosis, 80 samples of raw buffalo milk and 315 samples of mozzarella were tested for the presence of Brucella spp. Samples originated from Caserta, the province with the highest number of Brucella-positive buffalo herds in Campania, the region in which 96.02% of all cases of human brucellosis reported in 2000-2005 were recorded. To take into account possible seasonal variations, between February 2006 and March 2007, samples were purchased directly from 72 dairy outlets that were representative of the province. Samples were tested for Brucella spp. using the polymerase chain reaction (PCR) and bacterial isolation. Samples tested negative for Brucella using both methods. Spiked samples were then prepared and tested by PCR and bacterial isolation and the sensitivity, specificity, repeatability, reproducibility and limit of detection were determined. The PCR limit of detection was below 1 colony-forming unit (cfu)/g. The repeatability and reproducibility of the method were 100% (p = 0.95), the sensitivity was 96.7% (p = 0.95) and the specificity was 100% (p = 0.95).