In this study, we isolated 12 of Brucella (B.) spp. from cattle, which have been positive in Rose Bangal test and tube agglutination test in Gyeongbuk province in 2009. According to AMOS PCR analysis, isolated 12 strains were identified as B. abortus. Murine derived macrophage, RAW 264.7 cells, were infected with isolated 12 strains or reference strain (B. abortus 544), and bacterial internalization were characterized. According to these results, we divided the isolated strains into the following three groups: class Ⅰ, lower internalization than that of B. abortus 544; class Ⅱ, similar internalization to that of that of B. abortus 544; class Ⅲ, higher internalization than that of B. abortus 544 within RAW 264.7 cells. Furthermore, intracellular growth, bacterial adherent assay, LAMP-1 colocalization, virulence in mice and surface protein pattern were characterized. From these results, representative strains of class Ⅲ showed lower LAMP-1 colocalization, higher adherent efficiency, higher virulence in mice than those of B. abortus 544, and showed different pattern of surface proteins. These results suggest that B. abortus field strains, isolated from cattle in Korea, possess various virulence properties and higher internalization ability of field strain may have an important role for its virulence expression.

The pathogenicity and acute toxicity of Lactobacillus (L.) pentosus PL11 from eel (Anguilla japonica) were investigated using male and female Sprague-Dawley rats. The pathogenicity of L. pentosus PL11 was examined after treating the rats with 10∨11 CFU/mL, 10∨9 CFU/mL or 10∨7 CFU/mL doses of L. pentosus PL11 culture or 0.85% NaCl (Control) intragastrically. For acute toxicity studies, rats were treated with dried culture broth of L. pentosus PL11 at doses of 5,000 mg/mL, 2,500 mg/mL, 1,250 mg/mL or 625 mg/mL or Lactobacilli MRS broth (Control), and clinical signs or mortalities were monitored for two weeks. The results of the present investigation revealed no mortalities or obvious clinical signs in rats administered with the live bacterial cultures or dried culture broth at any investigated dose level. Also, no significant differences were observed in net body weight gain, gross pathological findings, feed and water consumption and body temperature among the different treatment groups and between the treated and control rats. It can be concluded from the above findings that L. pentosus PL11 is a safe probiotic strain with potential as feed additive to increase the feed efficiency or health of fish.

A stable and reliable Helicobacter pylori (H. pylori) infection animal model would be necessary for evaluating vaccine efficacy and helpful for understanding the pathological mechanism of the organism. The aim of the present study is to investigate the effect of ethanol treatment prior to H. pylori inoculation on associated gastric mucosal injury and to establish ethanol-pretreating animal model to study H. pylori infection. Male Mongolian gerbils were used for the study. H. pylori was orally inoculated after 12 h fasting.

The shigellae are common etiological agents of bacillary dysentery in humans and primates. During four years from 2002 to 2005, 22 strains of Shigella spp. were isolated from the diarrheic patients in Seoul region. All of them were identified as S. flexneri by biochemical tests and serotyping. The prevalence of serotypes were variable by year, but the major serotypes were 2a and 3a. In an antimicrobial susceptibility test, all of the isolates were resistant to streptomycin and tetracycline, and susceptible to amikacin, kanamycin, cefoxitin, and gentamicin.

The present study was carried out to investigate the prevalence of mycoplasmal pneumonia of slaughter pigs in Youngnam area during the period from 1995 to 1997. The prevalence and pathomorphology of gross lung lesions were studied from 682 slaughter pigs in 8 swine herds. Gross lesions of pneumonia were recorede in the lungs of 442(64.8%), from 367 out of them(83.0%) were diagnosed as mycoplasmal pneumonia. Microbiological examination was performed with 197 lungs with gross lesions of mycoplasmal pneumonia of slaughter pigs from 8 differentswine herds. M hyopneumoniae, P multocida, A pleuropneumoniae, Streptococcus spp, Corynebacterium spp, and H parasuis were detected in 24.4%, 48.2%, 2.5%, 11.2%, 3.6%, and 1.0% of the pneumonic lungs, respectively. A total of 48 strains of M hyopneumoniae was investigated for thier in vitro susceptibility to antibiotics. Among the drugs tested, lincomycin, oxytetracycline, tiamulin and tylosin showed the high activity in minimal inhibitory concentration(MIC) of 0.04-5 micro gram/ml while erythromycin showed low activity in MIC values(1.25~40micro gram/ml).

The purpose of this study was to establish a rapid, reliable diagnostic method detecting Encephalomyocarditis virus(EMCV) RNA in formalin-fixed, paraffin-embedded tissues of EMCV naturally infected pigs by cDNA probe of EMC K3, the EMCV strain isolated from Korea. Using a biotin-labelled nick translated probe for the cDNA marker. We made up for some defects of radiolabeled method. In situ hybridization(ISH) technique, differently from theother nucleic acid hybridization methods, is able to detect the virus genome specifically in the state of the intact shapes of cells and/or tissues. We succeeded in performing the experiment to detect the EMCV within 1~2 hours usign the MicroProbeTM capaillary action system. In this study, we ovserved highly specific positive sighals of red color by staining the paraffinembedded tissue sections of naturally EMCV-infected pig organs or tissues, including brain, heart, kidney and lacrimal gland with the Fast Red TR salt/Naphtol phosphate chromogen. The results suggested that this ISH method is considered as a highly sensitive and reliable tool for molecular biologic diagnosis of the EMC viral disease.

This study was conducted to investigate the pathogenicity of Paenibacillus (P.) polymyxa JB115 and single oral dose toxicity of culture broth containing β-glucan (CBG-JB115) produced from P. polymyxa JB115 in Sprague-Dawely rats of both sexes for 14 days. After oral administration of P. polymyxa JB115 into rats, we could not find any abnormal clinical signs and variation in the body weight and temperature as compared with control group. We also investigated the acute toxicity of CBG-JB115. As the results, there were no clinical signs and variance in the body weight and temperature related with CBG-JB115 in comparison with the control group.

The purpose of this study was to evaluate effect of chitosan-oligosaccharides(CHIOL) on hydrophobicity of pathogenic E coli including a field isolate from suckling piglet with diarrhea, E coli-0157:H7, and E coli-O149:K88ac. E coli field isolate appeared adhesion of 100% to n-hexadecne between 0.00125% and 0.05% CHIOL. E coli-O157:H7 occurred adhesion of 69% and 64% under the level of 0.00125% and 0.025% CHIOL, respectively. E coli-O149:K88ac showed adhesion of 100% in higher than 0.025% CHIOL. For cationic action, the adhesion of E coli isolate and E coli-O149:K88ac to n-hexadecane were inhibited at level of higher than 10mM Ca2+ but did not induce any difference among the concentrations used(p0.01). However,the adhesion of E coli-O157:H7 to n-hexadecane was inhibited at level of higher than 50mM Ca2+. In a field trial, control piglets showed average mortality of up to 58% during 3 days after the onset of diarrhea. In contrast, the prevalence of E coli-induced diarrhea in CHIOL-treated groups without mortality was dropped down to average 34% on the 1st day after the treatment of CHIOL, and average 2% on the 4th day. After then, piglets with diarrhea was not present. In conclusion, the low concentrations of CHIOL were most likely to associate with the enhancement of hydrophobicit to pathogenic E coli. Calcium inhibited the hydrophobicity of E coli by CHIOL. These results suggested that CHIOL could be played an efficient and reliable role in treating enteric colibacillosis of piglets.

The 2,078 blood samples from 148 swine farms were collected and tested by IFA for porcine reproductive and respiratory syndrome(PRRS) virus antibody to know what type of PRRS prevails by the area. Clnically reproductive form of PRRS occurred in swine farms of 3/27, 3/87, and 2/34 in estern, central and western areas, but the seroprevalence of those areas ws different as 6.5%, 23.3%, and 17.6%, respectively. However, respiratory form of PRRS occurred more frequently, and the number of farms manifested with the respiratory form of PRRS in the eastern, central and western areas was 22/27, 71/87, and 30/34, respectively. The seroprevalence of that form of PRRS in the eastern, central and western areas was 52.2%m 67.1%, and 51.6%, respectively. Sybsequently mixed form of PRRS ocurred more frequently in the central area and the number of farms of eastern, central and western areas was 2/27, 13/87, and 2/34, respectively. The PRRS seroprevalence of the eastern, central and western areas was 58.6%, 54.0%, and 19.2%, respectively. Collectively the PRRS seroprevalence of eastern, central and western areas was 43.8%, 59.3%, and 38.2%, respectively. Overall seroprevalence of PRRS in Korea was 51.8%. In conclusion, the reproductive or the respiratory form of PRRS has been still in trouble inthe Korean swine industry and PRRS control measures have to be taken in consideration.

Helicobacter pylori (H. pylori)-infection is an important pathogen of stomach cancer after chronic gastritis and ulceration in the stomach and duodenum. However, the virulences of H. pylori strains have not been well-defined between clinical isolates. This study was designed to establish water-immersion-restraint stress (WIRS) model in mongolian gerbil for comparison of pathogenicity of H. pylori strains. To determine an optimal duration time for WIRS model in gerbil, 5-week-old Mongolian gerbils were divided into different groups by WIRS duration time.