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Heavy metals in food are non-intentional pollutants such as lead (Pb), cadmium (Cd), and mercury (Hg). Pb, a neurotoxic substance, is classified as a possible carcinogen for humans (group 2B) by the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO). Cd, a substance that causes kidney damage, is classified as a substance that causes human cancer (group 1). In this study, inductively coupled plasma atomic emission spectrometry (ICP-AES) and a mercury analyzer (MA) were used to identify the concentrations of heavy metals (Pb, Cd, Hg) in fishery products and to assess the effects of chronic human exposure to heavy metals via fisheries consumption. Food consumption data were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES 2010-2015), and the mean exposure concentrations for Pb, Cd, and Hg were 0.0067 μg/kg bw/day, 1.1277 μg/kg bw/month, and 0.0872 μg/kg bw/week, respectively. Exposures to Pb, Cd, and Hg using the 95th percentile of the consumption data were 0.0183 μg/kg bw/day, 4.0230 μg/kg bw/month, and 0.2268 μg/kg bw/week, respectively, corresponding to 3, 16, and 6% of the human exposure safety standard. Safe guidelines for the intake of fishery products are proposed to reduce the exposure to and accumulation of heavy metals in humans.

Pasteurella multocida causes single or complex respiratory disease in pigs. Although antimicrobial therapy is the most effective treatment for porcine respiratory disease, P. multocida shows increased antimicrobial resistance in Korea. Therefore, we aimed to investigate the phenotypic and genotypic characterization of tetracycline-resistant P. multocida. Thirty-seven of 454 P. multocida isolates from South Korea between 2010 and 2016 were selected. Four tet genes [tet(B) (78.4%), tet(H) (16.2%), tet(C) (5.4%), and tet(O) (2.7%)] were observed. This is the first report of tet(C) in P. multocida. Various virulence factors were observed in both tetracycline-resistant and -susceptible P. multocida isolates. Genes encoding pmHAS and pfhA were more prevalent in tetracycline-resistant than in tetracycline-susceptible isolates. Some virulence factors exhibited association with serogroups. tadD and sodA were common in serogroup A, while hsf-l was significantly associated with serogroup D (p < 0.01). Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) results showed the genetic diversity of tetracycline-resistant P. multocida. MLST showed six different sequence types (ST), with clonal complex 13 encompassing 56.8% of the strains. PFGE was more efficient in differentiating the isolates, and 29 PFGE patterns of the strains were observed. By combining these methods, identical STs and PFGE patterns were observed in isolates from different farms, suggesting that transmission of antimicrobial-resistant P. multocida strains between farms might occur in a geographically discrete population. In future, epidemiological approaches and development of effective vaccines should focus on the major clonal lineages carrying the important virulence factors and frequently observed resistance genes to prevent the transmission and control the disease.

Pasteurella multocida is one of the significant causes of respiratory infection outbreaks in the Korean pig industry. Although antimicrobial treatment is an effective strategy for controlling respiratory diseases, limited information is available regarding the antimicrobial susceptibility of the pathogens infecting Korean pigs. Therefore, in this study, we evaluated the antimicrobial resistance of P multocida against widely used antimicrobials in order to enable the selection of appropriate drugs and to evaluate any trends in resistance. A total of 454 isolates of P multocida were collected from all provinces in Korea between 2010 and 2016. Antimicrobial susceptibility of all isolates was determined using a broth microdilution method. The most frequently observed resistance was to sulphadimethoxine (76.0 per cent), followed by oxytetracycline (66.5 per cent), chlortetracycline (36.8 per cent) and florfenicol (18.5 per cent). Although no consistent increase or decrease in resistance was observed for most antimicrobials, resistance to fluoroquinolones tended to increase over the study period. A variety of resistance patterns were observed, most frequently for tetracyclines and sulphonamides. These findings could provide information enabling the selection of optimal antimicrobials for efficient treatment of pneumoniae pasteurellosis in pig farms, which would impede the emergence of antimicrobial resistance.