Report on the presence of Salmonella and Campylobacter spp. in fresh meat marketed in Italy

Introduction

Salmonella (S.) and Campylobacter (C.) are the most common agents of foodborne infections and a risk for immunocompromised patients. The present study reports the prevalence and characterization of S. spp. in imported poultry, beef and pork meat marketed in Italy over six years. Furthermore, we present data of prevalence and species identification for C. spp. isolated from poultry samples collected in the years 2016 and 2018.

Methods

Poultry (chicken and turkey), beef and pork meat samples were collected by Health Local Authorities all over Italy. The presence of C. was tested according to the ISO 10272 and the species identification was assessed using Multiplex PCR (C. coli e C. jejuni). S. was tested according ISO 6579 and serovars were identified through serum agglutination using S. antisera.

Results

The prevalence of S. in chicken and turkey was respectively 1.31% (4/306) and 0% in 2016, 7.89% (24/304) and 2.33% (7/300) in 2018, 14.4% (37/257) and 3.59% (9/251) in 2020; S. was never detected in beef meat but it was found in 1.05% (3/287) of pork samples in 2015, 1.98% (5/253) in 2017, 1.74% (5/287) in 2019. Among all the available samples, the most common serotypes identified were S. Infantis and S. Bredeney. The presence of C. was detected in 4.25% (13/306) of chicken samples and in 0.74% (2/272) of turkey samples in 2016, increasing respectively to 17% (17/100) and 1.06% (1/94) in 2018. Similar frequencies were found for coli and jejuni species.

Conclusions

The results show that poultry meat is the most relevant source of C. and S. Uncooked or not well-cooked meat can still be a risk for the consumers, despite the adoption of biosecurity measures suited to prevent S. to enter in farms. Source attribution and prevalence studies like this can be a useful tool to set up monitoring plans, identify priorities for food safety interventions and risk communication.

Key messages

The crucial role of source attribution studies to help Authorities to plan further controls. Public agencies and stakeholders should give clear communication about the risk of not well-cooked meat.

Utility of gene expression studies in relation to radiation exposure and clinical outcomes: thyroid cancer in the Ukrainian-American cohort and late health effects in a MAYAK worker cohort

PURPOSE

We herein report on changes in gene expression after radiation exposure to iodine-131 from the Chernobyl accident in the Ukrainian-American thyroid cohort and to external gamma ray or internal plutonium exposure in the Mayak Production Association radiation workers.

MATERIALS AND METHODS

Taking advantage of access to tissue samples from the thyroid cancer cases in the Ukrainian-American cohort, our group tried to identify candidate genes to discriminate spontaneously occurring thyroid cancers from thyroid cancers caused by radiation exposure. We also examined gene expression changes in normal and cancerous thyroid tissue in relation to iodine-131 dose separately. Gene expression changes in the peripheral blood of radiation exposed Mayak workers were examined to elucidate the dose-to-gene and gene-to-health (e.g. cardiovascular disease) relationships.

CONCLUSIONS

Results of both projects are discussed under the aspect of dose-response relationships (dose-to-gene) and clinical outcome relationships (gene-to-effect) in light of how mechanistic data can be translated into actionable knowledge for radiation protection or clinical purposes.

Histopathological characteristics and post-operative follow-up of patients with potentially radiogenic papillary thyroid carcinoma depending on oncocytic changes availability in the tumor cells

AIM

To compare the frequency of main histopathological characteristics, 131І thyroid radiation doses, invasive properties and post-operative follow-up of patients of different age groups with potentially radiogenic papillary thyroid carcinoma (PTC) with the presence and absence of oncocytic changes in tumor cells.

MATERIALS AND METHODS

PTC removed in 483 patients from high risk age-group for radiogenic thyroid cancer development (children and adolescents at the time of Chornobyl accident who lived in the northern regions of Ukraine: Kyiv, Zhytomyr, and Chernihiv regions) have been studied microscopically.

RESULTS

The frequency of PTC with the presence of oncocytic changes (OCh) in tumor cells increased significantly with increasing of patients' age at the time of surgery: from 8.3% in children 4-14 years old to 54.3% in adults 39-48 years old (ptrend < 0.0001). The presence of such changes is associated with papillary and solid-trabecular dominant tumor growth pattern in more than 90% of cases in each age group. The mean 131І thyroid dose in the whole series of PTC patients with OCh was significantly lower compared to the same index in PTC patients without OCh (493.7 mGy and 765.8 mGy, respectively, p < 0.0001). In addition, regional metastases recurrences were revealed more frequently in patients with OCh in primary PTC compared with patients without OCh in primary tumor (7.2% vs 1.5%, p = 0.0022).

CONCLUSIONS

Significantly increasing age-trend of OCh in PTC of patients affected by the Chornobyl fallout and operated at age from 4 to 48 years, as well as opposite decreasing linear age-trend of 131І thyroid dose may reflect a gradual increase of sporadic PTCs frequency in the potentially radiogenic series with time elapsed since accident. The frequency of oncocytic insensitive to radioiodine therapy of lymph node metastases recurrences also increased with patients age and OCh availability in primary PTC.

MORPHOLOGICAL CHARACTERISTICS OF CHRONIC GASTRODUODENITIS IN ADOLESCENTS WITH FOOD HYPERSENSITIVITY

The aim of our work was to evaluate the morphological features of the mucous membrane of the stomach and duodenum in children with chronic diseases of the gastroduodenal zone on the background of food hypersensitivity. Morphological study was conducted for 50 adolescents aged 12 to 17 years who were in inpatient treatment in the gastroenterology department. In order to verify the diagnosis, all children were checked by fibroesophagogastroduodenoscopy of the upper digestive tract with biopsy of the mucous membrane of the stomach antrum and the descending part of the duodenum. Bioptates were stained by hematoxylin-eosin, Van Gieson and performed on light microscope. The results of the research of the mucous membrane of the stomach and duodenum show that adolescents with chronic gastroduodenitis and food hypersensitivity have 17 times higher risk of developing atrophy of duodenal mucous membrane, 11 times higher frequency of eosinophilic infiltration and 3 times higher incidence of mucous membrane fibrosis in the duodenum.

Identification of kinase fusion oncogenes in post-Chernobyl radiation-induced thyroid cancers

Exposure to ionizing radiation during childhood markedly increases the risk of developing papillary thyroid cancer. We examined tissues from 26 Ukrainian patients with thyroid cancer who were younger than 10 years of age and living in contaminated areas during the time of the Chernobyl nuclear reactor accident. We identified nonoverlapping somatic driver mutations in all 26 cases through candidate gene assays and next-generation RNA sequencing. We found that 22 tumors harbored fusion oncogenes that arose primarily through intrachromosomal rearrangements. Altogether, 23 of the oncogenic drivers identified in this cohort aberrantly activate MAPK signaling, including the 2 somatic rearrangements resulting in fusion of transcription factor ETS variant 6 (ETV6) with neurotrophic tyrosine kinase receptor, type 3 (NTRK3) and fusion of acylglycerol kinase (AGK) with BRAF. Two other tumors harbored distinct fusions leading to overexpression of the nuclear receptor PPARγ. Fusion oncogenes were less prevalent in tumors from a cohort of children with pediatric thyroid cancers that had not been exposed to radiation but were from the same geographical regions. Radiation-induced thyroid cancers provide a paradigm of tumorigenesis driven by fusion oncogenes that activate MAPK signaling or, less frequently, a PPARγ-driven transcriptional program.

Reconstruction of individual thyroid doses to the Ukrainian subjects enrolled in the Chernobyl Tissue Bank

The Chernobyl Tissue Bank (CTB) is an organisation that collects and stores samples of tumoral thyroid tissue obtained from Ukrainian and Russian subjects who were treated surgically for a thyroid cancer and had been exposed to (131)I from the Chernobyl accident. By 2012, the CTB had collected specimens of thyroid tissue from 2267 residents of Ukraine for the purpose of radiation research. Arithmetic mean thyroid doses and uncertainties have been estimated for all but 24 subjects for whom residence at the time of exposure was not found. The subjects have been classified into six groups or sub-groups according to the type of dosimetry-related information that is available for each of them. Excluding the 325 subjects with negligible radiation exposure, the arithmetic mean of the thyroid dose over all subjects is estimated as 0.4 Gy, with individual values ranging from <1 mGy to 13 Gy. The uncertainties in the individual thyroid dose estimates, characterised by the geometric standard deviations of their probability distributions, range from 1.3 to 8.7, with an arithmetic mean of 3.2.

Radiation induced thyroid cancer: fundamental and applied aspects

AIM

To describe the epidemiology and pathology of thyroid cancer in Ukraine, and to perform the molecular analysis of genetic alterations more frequently found to be associated to papillary carcinomas (PTC) in a selected group of PTC.

MATERIALS AND METHODS

Relationship between the thyroid cancer incidence and gender, age, and place of residence of subjects aged 0-18 years at the time of the Chernobyl accident (5427 subjects of thyroid cancer, among which 3996 (73.6%) were children aged 0 to 14 years at the time of the accident, and 1431 (26.3%) were adolescents aged 15 to 18 years was studied. Pathologically analyzed thyroid carcinomas were obtained from 640 patients (20-40 years old at the time of surgery and born before the Chernobyl accident), and from 90 patients (11-22 years old at the time of surgery and born after the accident). All patients were operated during 2006-2008. RET/PTC rearrangements and BRAF(V600E) mutation were analyzed in 35 cases of PTC.

RESULTS

A comparison between the thyroid cancer incidence rates in the 6 highest contaminated regions of Ukraine and in the other 21 regions shows the most significant difference between the rates for the last three years of follow-up, which confirms that a direct relationship is still present between the rise in thyroid cancer incidence and the post Chernobyl radiation exposure. Much lower incidence of thyroid cancer in subjects, who were born after the accident, additionally confirmed a direct relationship between the Chernobyl accident and thyroid cancer development at least in those who were aged up to 18 years at the time of the nuclear accident. Pathological results showed that with increasing latency the decrease has been noted in the percentage of PTC with solid structure, a decrease in invasive properties of tumors, as well as an increase in the percentage of PTC with papillary-follicular structure, encapsulated forms, and <<small>> carcinomas measuring up to 1 cm. Molecular-biological studies of PTC revealed more common RET/PTC1 and RET/PTC3 rearrangements (34.3% of cases), than BRAFV600E mutation (24%cases).

CONCLUSION

After 22 years from the Chernobyl nuclear accident the number and incidence of thyroid cancer cases in Ukraine was steadily increased in the cohort of those who were children and adolescents at the time of the accident. Most common thyroid tumors (PTC) were characterized by significant changes in histological structure with increasing latency. PTC with any RET/PTC rearrangements had more aggressive behavior than BRAF(V600E)-positive tumors or PTC without gene alterations.

A screening study of thyroid cancer and other thyroid diseases among individuals exposed in utero to iodine-131 from Chernobyl fallout

BACKGROUND

Like stable iodine, radioiodines concentrate in the thyroid gland, increasing thyroid cancer risk in exposed children. Data on exposure to the embryonic/fetal thyroid are rare, raising questions about use of iodine 131 (I-131) in pregnant women. We present here estimated risks of thyroid disease from exposure in utero to I-131 fallout from the Chernobyl nuclear accident.

METHODS

We conducted a cross-sectional thyroid screening study (palpation, ultrasound, thyroid hormones, and, if indicated, fine needle aspiration) from 2003 to 2006. Participants were 2582 mother-child pairs from Ukraine in which the mother had been pregnant at the time of the accident on April 26, 1986, or 2 months after the time during which I-131 fallout was still present (1494 from contaminated areas, 1088 in the comparison group). Individual cumulative in utero thyroid dose estimates were derived from estimated I-131 activity in the mother's thyroid (mean 72 mGy; range 0-3230 mGy).

RESULTS

There were seven cases of thyroid carcinoma and one case of Hurthle cell neoplasm identified as a result of the screening. Whereas the estimated excess odds ratio per gray for thyroid carcinoma was elevated (excess odds ratio per gray 11.66), it was not statistically significant (P = 0.12). No radiation risks were identified for other thyroid diseases.

CONCLUSION

Our results suggest that in utero exposure to radioiodines may have increased the risk of thyroid carcinoma approximately 20 yr after the Chernobyl accident, supporting a conservative approach to medical uses of I-131 during pregnancy.

Genome-wide gene expression profiling suggests distinct radiation susceptibilities in sporadic and post-Chernobyl papillary thyroid cancers

Papillary thyroid cancers (PTCs) incidence dramatically increased in the vicinity of Chernobyl. The cancer-initiating role of radiation elsewhere is debated. Therefore, we searched for a signature distinguishing radio-induced from sporadic cancers. Using microarrays, we compared the expression profiles of PTCs from the Chernobyl Tissue Bank (CTB, n=12) and from French patients with no history of exposure to ionising radiations (n=14). We also compared the transcriptional responses of human lymphocytes to the presumed aetiological agents initiating these tumours, γ-radiation and H₂O₂. On a global scale, the transcriptomes of CTB and French tumours are indistinguishable, and the transcriptional responses to γ-radiation and H₂O₂ are similar. On a finer scale, a 118 genes signature discriminated the γ-radiation and H₂O₂ responses. This signature could be used to classify the tumours as CTB or French with an error of 15–27%. Similar results were obtained with an independent signature of 13 genes involved in homologous recombination. Although sporadic and radio-induced PTCs represent the same disease, they are distinguishable with molecular signatures reflecting specific responses to γ-radiation and H₂O₂. These signatures in PTCs could reflect the susceptibility profiles of the patients, suggesting the feasibility of a radiation susceptibility test.

Gene expression and the biological phenotype of papillary thyroid carcinomas

The purpose of this paper is to correlate the molecular phenotype of papillary thyroid carcinoma (PTC) to their biological pathology. We hybridized 26 PTC on microarrays and showed that nearly 44% of the transcriptome was regulated in these tumors. We then combined our data set with two published PTC microarray studies to produce a platform- and study-independent list of PTC-associated genes. We further confirmed the mRNA regulation of 15 genes from this list by quantitative reverse transcription-PCR. Analysis of this list with statistical tools led to several conclusions: (1) there is a change in cell population with an increased expression of genes involved in the immune response, reflecting lymphocyte infiltration in the tumor compared to the normal tissue. (2) The c-jun N-terminal kinase pathway is activated by overexpression of its components. (3) The activation of ERKK1/2 by genetic alterations is supplemented by activation of the epidermal growth factor but not of the insulin-like growth factor signaling pathway. (4) There is a downregulation of immediate early genes. (5) We observed an overexpression of many proteases in accordance with tumor remodeling, and suggested a probable role of S100 proteins and annexin A2 in this process. (6) Numerous overexpressed genes favor the hypothesis of a collective migration mode of tumor cells.

Post-Chornobyl Thyroid Cancers in Ukraine. Report 2: Risk Analysis

On April 26, 1986, the worst nuclear reactor accident to date occurred at the Chornobyl (Chernobyl) power plant in Ukraine. Millions of people in Ukraine, Belarus and Russia were exposed to radioactive nuclides, especially (131)I. Since then, research has been conducted on various subgroups of the exposed population, and it has been demonstrated that the large increase in thyroid cancer is related to the (131)I exposure. However, because of study limitations, quantified risk estimates are limited, and there remains a need for additional information. We conducted an ecological study to investigate the relationship between (131)I thyroid dose and the diagnosis of thyroid cancer in three highly contaminated oblasts in Northern Ukraine. The study population is comprised of 301,907 persons who were between the ages of 1 and 18 at the time of the Chornobyl accident and were living in 1,293 rural settlements in the three study oblasts. Twenty-four percent of the study population had individual thyroid dose estimates and the other 76% had "individualized" estimates of thyroid dose based on direct thyroid measurements taken from a person of the same age and gender living in the same or nearby settlement. Cases include 232 thyroid cancers diagnosed from January 1990 through December 2001, and all were confirmed histologically. Dose-response analyses took into account differences in the rate of ultrasound examinations conducted in the three study oblasts. The estimated excess relative risk per gray was 8.0 (95% CI = 4.6-15) and the excess absolute risk per 10,000 person-year gray was estimated to be 1.5 (95% CI = 1.2-1.9). In broad terms, these estimates are compatible with results of other studies from the contaminated areas, as well as studies of external radiation exposure.

RET rearrangements in post-Chernobyl papillary thyroid carcinomas with a short latency analysed by interphase FISH

Tissue samples from 13 post-Chernobyl childhood thyroid tumours that occurred within a short period of time (4–8 years) after the Chernobyl accident have been investigated by interphase FISH analysis for rearrangements of RET. In all, 77% of cases showed RET/PTC rearrangements and a distinct intratumoural genetic heterogeneity. The data were compared to findings on 32 post-Chernobyl PTCs that occurred after a longer period of time (9–12 years) after the accident. In none of the cases from either group were 100% of cells positive for RET rearrangement. In addition, the pattern of RET-positive cells was different in the two groups (short vs longer latency). A significant clustering of aberrant cells could be detected in the long-latency subgroup, whereas the aberrant cells were more homogeneously distributed among the short-latency tumours. The findings suggest that oligoclonal tumour development occurs in post-Chernobyl PTCs. This pattern of different clones within the tumour appears to become more discrete in cases with longer latencies, suggesting either outgrowth of individual clones or development of later subclones with time.

Cancer consequences of the Chernobyl accident: 20 years on

26 April 2006 marks the 20th anniversary of the Chernobyl accident. On this occasion, the World Health Organization (WHO), within the UN Chernobyl Forum initiative, convened an Expert Group to evaluate the health impacts of Chernobyl. This paper summarises the findings relating to cancer. A dramatic increase in the incidence of thyroid cancer has been observed among those exposed to radioactive iodines in childhood and adolescence in the most contaminated territories. Iodine deficiency may have increased the risk of developing thyroid cancer following exposure to radioactive iodines, while prolonged stable iodine supplementation in the years after exposure may reduce this risk. Although increases in rates of other cancers have been reported, much of these increases appear to be due to other factors, including improvements in registration, reporting and diagnosis. Studies are few, however, and have methodological limitations. Further, because most radiation-related solid cancers continue to occur decades after exposure and because only 20 years have passed since the accident, it is too early to evaluate the full radiological impact of the accident. Apart from the large increase in thyroid cancer incidence in young people, there are at present no clearly demonstrated radiation-related increases in cancer risk. This should not, however, be interpreted to mean that no increase has in fact occurred: based on the experience of other populations exposed to ionising radiation, a small increase in the relative risk of cancer is expected, even at the low to moderate doses received. Although it is expected that epidemiological studies will have difficulty identifying such a risk, it may nevertheless translate into a substantial number of radiation-related cancer cases in the future, given the very large number of individuals exposed.

Absence of a specific radiation signature in post-Chernobyl thyroid cancers

Thyroid cancers have been the main medical consequence of the Chernobyl accident. On the basis of their pathological features and of the fact that a large proportion of them demonstrate RET-PTC translocations, these cancers are considered as similar to classical sporadic papillary carcinomas, although molecular alterations differ between both tumours. We analysed gene expression in post-Chernobyl cancers, sporadic papillary carcinomas and compared to autonomous adenomas used as controls. Unsupervised clustering of these data did not distinguish between the cancers, but separates both cancers from adenomas. No gene signature separating sporadic from post-Chernobyl PTC (chPTC) could be found using supervised and unsupervised classification methods although such a signature is demonstrated for cancers and adenomas. Furthermore, we demonstrate that pooled RNA from sporadic and chPTC are as strongly correlated as two independent sporadic PTC pools, one from Europe, one from the US involving patients not exposed to Chernobyl radiations. This result relies on cDNA and Affymetrix microarrays. Thus, platform-specific artifacts are controlled for. Our findings suggest the absence of a radiation fingerprint in the chPTC and support the concept that post-Chernobyl cancer data, for which the cancer-causing event and its date are known, are a unique source of information to study naturally occurring papillary carcinomas.

Frequency of BRAF T1796A mutation in papillary thyroid carcinoma relates to age of patient at diagnosis and not to radiation exposure

In this study, the frequency of BRAF mutation was investigated in a series of 67 cases of papillary thyroid cancer (PTC) in patients from Ukraine. Thirty-two patients were aged 30 years or older at the time of diagnosis and 35 were under 16. Tumour was microdissected from paraffin wax-embedded sections, DNA extracted, and the presence of the BRAF T1796A mutation demonstrated by two different methods: PCR followed by restriction enzyme digestion or primer extension assay and detection using MALDI-TOF mass spectrometry. Eighteen (58%) of the adult cases, but only one of the 35 cases aged less than 16 harboured a BRAF T1796A mutation. There was complete agreement between the two methods used, suggesting that the MALDI-TOF assay is a robust alternative to conventional mutation analysis. RET rearrangement was also examined in the young cohort. The overall frequency of RET rearrangement was 45.7%. Eight of the younger group of patients were born after 1 December 1986 and were therefore not exposed to radioiodine in fallout from Chernobyl. None of the PTCs from these eight patients were positive for BRAF mutation. The frequency of RET rearrangement was 44% in the 27 cases exposed to radiation and 50% in the eight not exposed. These results suggest that the different molecular biological profiles observed are associated with the age of the patient at diagnosis with PTC, rather than being associated with radiation exposure.

Thyroid carcinoma after Chernobyl latent period, morphology and aggressiveness

The large numbers of papillary thyroid carcinomas that have occurred in those exposed to high levels of short-lived isotopes in fallout after Chernobyl provide a unique opportunity to correlate latency and tumour biology. We show that short latency is associated with tumours with a phenotype that is significantly less structurally differentiated, shows significantly less peritumour fibrosis, and significantly more invasive spread when compared to tumours with a longer latent period. In contrast, the type of differentiation (papillary or follicular architecture) is associated with age at exposure. These findings suggest that the initial mutation at the time of exposure played a major role in tumour latency and aggressiveness. We and others have shown that RET-PTC3 rearrangements are associated with the solid morphology seen in these short latency tumours, while classical papillary carcinomas more often show RET-PTC1 rearrangements. Studies in transgenic mice show similar findings, and in vitro studies show that RET-PTC3 induces more rapid growth than RET-PTC1. We therefore suggest that the solid morphology, high frequency of RET-PTC3 rearrangements and aggressive behaviour noted in early investigations of post-Chernobyl tumours were characteristic of short latency rather than the nature of the mutagen, and that successive overlapping waves of papillary carcinoma with differing latency, differing patterns of mutations and differing clinical behaviour are occurring in those exposed to Chernobyl fallout.

Single nucleotide polymorphism analysis in the human phosphatase PTPrj gene using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry

Data derived from analysis of single nucleotide polymorphisms (SNPs) are being applied in many diverse fields, from medical studies of disease mechanisms and individual drug response, to population genetics for tracking migration and mixing of ancestral groups and also in forensic science for the identification of human remains and identification of individuals from bodily samples. All these applications have in common the need to generate data for multiple loci from large numbers of samples. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS) is a promising platform for the generation of such data and we present a simple, flexible and robust technique for SNP determination. We demonstrate these features by typing two SNPs (Q276P and R326Q) in the human phosphatase gene PTPrj, which has been implicated in the aetiology of colon, lung, breast and thyroid cancers. A nucleotide depletion primer extension assay using no commercial kits or dideoxyNTPs was used to genotype a panel of DNAs derived from thyroid cancer patients and normal volunteers. The results obtained were in perfect agreement with those generated via restriction fragment length polymorphism analysis. No significant association was noted between possession of either allelic variant and a disease state, but the technique was validated as simple, flexible and appropriate for application in this context. Furthermore, it was highly cost-effective and required minimal optimisation, rendering it ideal for this type of pilot study.