Antibacterial activities of bark extracts from Fraxinus rhynchophylla Hance and Geranium koreanum Kom. against clinical strains of Clostridium perfringens in chickens / 대한수의학회지

Necrotic enteritis (NE) caused by Clostridium (C.) perfringens commonly occurs in domestic broiler farms since antibiotic supplementation in poultry feed has been banned. We evaluated the antibacterial activities of medicinal plant extracts against C. perfringens isolates to select alternative compounds for preventing NE. We compared antibacterial activities using two methods and evaluated susceptibilities of the isolates based on minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Two (Fraxinus rhynchophylla Hance [FRH] and Geranium koreanum Kom. [GKK]) of the 30 plant extracts had potent antibacterial activities against C. perfringens ATCC 13124 in two assays. The MIC values for FRH and GKK against 20 C. perfringens isolates were 128~256 microg/mL and 32~128 microg/mL, respectively. The geometric MIC mean values for the two extracts were 147.2 microg/mL and 68.8 microg/mL, respectively. The MBCs for the two extracts against the same strains were 1,024~2,048 microg/mL and 256~1,024 microg/mL, respectively. The geometric mean MIC and MBC for GKK were about two-fold lower than those of FRH. The modified spot-on-lawn assay may be useful for measuring primary antibacterial potential. FRH and GKK are expected to be used as feed additives to prevent or treat NE in veterinary practice.

Protective effects of a mineral aqueous solution on toxicity in mouse liver and kidney / 대한수의학회지

We demonstrated that a mineral aqueous solution (MAS) administered to mice functionally and histologically protected against cisplatin-induced acute renal failure (ARF) and CCl4-induced acute liver failure (ALF). In ARF model, 0.4 and 0.2% MAS decreased mortality and the serum concentrations of blood urea nitrogen (BUN) and creatine in mice. Additionally, 0.4 and 0.2% MAS reduced contraction of distal convoluted tubules and suppressed expression of the proinflammatory cytokines interlukein-6 (IL-6) and tumor necrosis factor (TNF-alpha) in the kidney. In ALF model, 0.4 and 0.2% MAS decreased serum concentrations of alanine aminotransferase and aspartate aminotransferase in mice. Additionally, 0.4 and 0.2% MAS reduced necrotic areas and suppressed expression of IL-6 and TNF-alpha in the liver. These results indicate that a MAS might have protective effects against ARF and ALF.

Identification of bacteria from the oral cavity and cloaca of snakes imported from Vietnam / 한국실험동물학회지

Reptiles are used for various purposes these days, including public exhibits, medicinal applications, and as laboratory animals. As the international exchange of reptiles has gradually increased, more people have had the opportunity to come in contact with these animals. Snakes typically live in the rhizosphere where various bacterial strains exist and as such they can lead to opportunistic human diseases. When snakes are encountered in veterinary medicine, it is necessary to monitor their microflora. Native microflora of reptiles imported from other countries has not yet been reported in Korea. In this study, oral and cloacae samples were collected from 18 Burmese pythons transported from Vietnam. The specimens were incubated at 37degrees C for 18 h to produce colony growth under aerobic condition and isolated colonies were then identified using a VITEK automated identification system. There were fourteen types of aerobic bacteria isolated from both oral and cloacae samples, nine from only oral specimens, and fifteen from only cloacae specimens. Most bacteria isolated were opportunistic pathogens of humans which therefore have the potential to induce disease in people. Based on the microflora and the prevalence of bacterial strains in snakes, quarantine procedures for reptiles transported internationally should be strengthened. Characterization of the microflora of reptiles with the potential to induce zoonosis should be performed in those used as laboratory animals and to prevent zoonotic outbreaks in the general population as well as among veterinarians.

Epidemiological Prevalence of Avian Pathogenic Escherichia coli Differentiated by Multiplex PCR from Commercial Chickens and Hatchery in Korea

We examined 216 Escherichia coli (E. coli) isolated from chickens and environmental specimens from hatcheries between 2005 and 2006 in order to evaluate the epidemiological prevalence of avian pathogenic E. coli (APEC) in Korea tentatively by multiplex PCR. The multiplex PCR which was used as tentative criteria of APEC targets 8 virulence-associated genes; enteroaggregative toxin (astA), increased serum survival protein (iss), iron-repressible protein (irp2), P fimbriae (papC), aerobactin (iucD), temperature-sensitive hemagglutinin (tsh), vacuolating autotransporter toxin (vat), and colicin V plasmid operon (cva/cvi) genes. The number of detected genes could be used as a reliable index of their virulence. It was demonstrated that E. coli strains already typed as APEC always harbor 5 to 8 genes, but non-APEC strains harbor less than 4 genes. Assuming the criteria of APEC is a possession of more than 5 virulenceassociated genes, we discriminated 24 APEC strains among the 216 E. coli strains. Contamination rates of APEC in the field were 31.3% in layers, 14.0% in broilers, 2.7% in broiler breeders, and 0.0% in environmental specimens from hatcheries. The combinational tendency of APEC examined is a fundamental possession of astA, iss and iucD genes and addition of cva/cvi, tsh, vat, and irp2 genes which have a critical importance for virulent traits of APEC. Compared with intravenous chicken challenge or embryo lethality assay, multiplex PCR method could be useful to discriminate APEC rapidly for convenient diagnosis.