Chemical, biological, and DNA markers for tracing slaughterhouse effluent

Occupational exposure to arsenic, mercury and UV radiation and risk of melanoma: a case-control study from Italy

BACKGROUND

Melanoma is mainly caused by sunlight radiation, but other environmental risk factors are not well known. We investigated the association between cutaneous melanoma and occupational exposure to arsenic, mercury and UV radiation.

METHODS

A hospital-based case-control study was conducted in the inpatient wards of IDI-San Carlo Rome, Italy, including 304 incident cases of cutaneous melanoma and 305 frequency-matched controls. Detailed sociodemographic, clinical and host-related factors were collected, and all participants were physically examined using dermoscopy and following standard protocol for recording pigmented lesions. Four experts assessed exposure to arsenic, mercury and UV radiation based on occupational history. A multidimensional variable was created for each risk factor, by combining intensity and probability of exposure. Multivariable logistic regression models were run to calculate odds ratios (OR) and 95% confidence intervals (CI) of the association between exposure to these agents and melanoma.

RESULTS

A total of 5.4% of the cases vs 2.4% of the controls were exposed to arsenic (OR = 3.12; 95% CI = 1.10-8.86 for high probability and high exposure to arsenic) after controlling for sex, age, smoking status, number of nevi, phototype and history of sunburns in childhood/adolescence. Occupational exposure to mercury and UV radiation was not associated with the risk of melanoma.

CONCLUSIONS

Subjects exposed to arsenic at the workplace may be at increased risk of developing cutaneous melanoma in comparison to subjects not exposed to this agent. Further studies should be designed to investigate occupational exposure to arsenic and mercury and melanoma and confirm the findings are warranted.

Association of Virulence and Antibiotic Resistance in Salmonella-Statistical and Computational Insights into a Selected Set of Clinical Isolates

The acquisition of antibiotic resistance (AR) by foodborne pathogens, such as Salmonella enterica, has emerged as a serious public health concern. The relationship between the two key survival mechanisms (i.e., antibiotic resistance and virulence) of bacterial pathogens is complex. However, it is unclear if the presence of certain virulence determinants (i.e., virulence genes) and AR have any association in Salmonella. In this study, we report the prevalence of selected virulence genes and their association with AR in a set of phenotypically tested antibiotic-resistant (n = 117) and antibiotic-susceptible (n = 94) clinical isolates of Salmonella collected from Tennessee, USA. Profiling of virulence genes (i.e., virulotyping) in Salmonella isolates (n = 211) was conducted by targeting 13 known virulence genes and a gene for class 1 integron. The association of the presence/absence of virulence genes in an isolate with their AR phenotypes was determined by the machine learning algorithm Random Forest. The analysis revealed that Salmonella virulotypes with gene clusters consisting of avrA, gipA, sodC1, and sopE1 were strongly associated with any resistant phenotypes. To conclude, the results of this exploratory study shed light on the association of specific virulence genes with drug-resistant phenotypes of Salmonella. The presence of certain virulence genes clusters in resistant isolates may become useful for the risk assessment and management of salmonellosis caused by drug-resistant Salmonella in humans.