This study aimed to survey the antimicrobial resistance profiles of 690 pathogenic Escherichia coli isolates obtained from Korean pigs with symptoms of enteric colibacillosis between 2007 and 2017, while assessing the change in antimicrobial resistance profiles before and after the ban on antibiotic growth promoters (AGPs). Following the Clinical and Laboratory Standards Institute guidelines, the antimicrobial resistance phenotype was analyzed through the disk diffusion method, and the genotype was analyzed by the polymerase chain reaction. After the ban on AGPs, resistance to gentamicin (from 68.8% to 39.0%), neomycin (from 84.9% to 57.8%), ciprofloxacin (from 49.5% to 39.6%), norfloxacin (from 46.8% to 37.3%), and amoxicillin/clavulanic acid (from 40.8% to 23.5%) decreased compared to before the ban. However, resistance to cephalothin (from 51.4% to 66.5%), cefepime (from 0.0% to 2.4%), and colistin (from 7.3% to 11.0%) had increased. We confirmed a high percentage of multidrug resistance before (95.0%) and after (96.6%) the ban on AGPs. The AmpC gene was the most prevalent from 2007 to 2017 (60.0%), followed by the blaTEM gene (55.5%). The blaTEM was prevalent before (2007–2011, 69.3%) and after (2012–2017, 49.2%) the ban on AGPs. These results provide data that can be used for the prevention and treatment of enteric colibacillosis.

Balantioides coli is a zoonotic protozoan parasite whose main reservoir is pigs. Recent studies have shown that B. coli variant A but not B has zoonotic potential. While B. coli infection has been reported in different animals and countries, the prevalence of the zoonotic variant is limited due to a lack of molecular information. Therefore, this study investigated the prevalence of B. coli in domestic pigs in Korea and assessed its zoonotic potential. A total of 188 pig fecal samples were collected from slaughterhouses in Korea. B. coli was identified by microscopy and molecular methods. B. coli was identified in 79 (42.9%) and 174 (94.6%) samples by microscopy and polymerase chain reaction (PCR), respectively. This study also developed a PCR-restriction fragment length polymorphism (PCR-RFLP) method to differentiate B. coli variant A from B without sequence analysis. Using this method, 62 (33.7%) and 160 (87.0%) samples were positive for variants A and B, respectively, and 48 (26.1%) samples were co-infected with both variants. Sequence and phylogenetic analyses showed a high genetic diversity of B. coli in pigs in Korea. To our knowledge, this is the first study to develop a method to differentiate B. coli variants A and B without sequence analysis and to assess the molecular epidemiology of B. coli in pigs. Continuous monitoring of zoonotic B. coli in pigs should be performed as pigs are the main source of human balantidiasis.

Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.

A 2-year-old Pekinese dog was diagnosed with hepatic yersiniosis. Grossly, white-to-yellow nodules consisting of degenerated inflammatory cells, cell debris, and bacterial clumps were scattered throughout the liver. Histopathologically, suppurative and necrotizing hepatitis was apparent. Yersinia enterocolitica biotype 4, serotype O3 (4:O3) was identified and confirmed in the liver immunohistochemically, using a monoclonal antibody. The virulence genes ystA and ail were detected, but the isolate was negative for autoagglutination and calcium-dependent growth. To confirm systemic yersiniosis in animals, it is imperative that the organism(s) be identified because the hepatic lesions are similar to those of Y. pseudotuberculosis and other diseases, including plague, which is also a zoonotic pathogen.