[Show abstract][Hide abstract]ABSTRACT: Human amniotic membrane-derived mesenchymal stem cells (hAM-MSCs) are capable of differentiating into several lineages and possess immunomodulatory properties. In this study, we investigated the soluble factor-mediated immunomodulatory effects of hAM-MSCs. Mitogen-induced peripheral blood mononuclear cell (PBMC) proliferation was suppressed by hAM-MSCs in a dose-dependent manner as well as hAM-MSC culture supernatant. Moreover, interferon-gamma and interleukin (IL)-17 production significantly decreased from PBMC, whereas IL-10 from PBMCs and transforming growth factor beta (TGF-β) production from hAM-MSCs significantly increased in co-cultures of hAM-MSCs and PBMCs. Production of several MSC factors, including hepatocyte growth factor (HGF), TGF-β, prostaglandin E2 (PGE2), and indoleamine 2, 3 dioxygenase (IDO), increased significantly in hAM-MSCs co-cultured with PBMCs. These results indicate that the immunomodulatory effects of hAM-MSCs may be associated with soluble factors (TGF-β, HGF, PGE2, and IDO), suggesting that hAM-MSCs may have potential clinical use in regenerative medicine.
Preview · Article · Mar 2012 · Journal of veterinary science (Suwŏn-si, Korea)
[Show abstract][Hide abstract]ABSTRACT: The Staphylococcus (S.) intermedius group (SIG) has been a main research subject in recent years. S. pseudintermedius causes pyoderma and otitis in companion animals as well as foodborne diseases. To prevent SIG-associated infection and disease outbreaks, identification of both staphylococcal exotoxins and staphylococcal cassette chromosome mec (SCCmec) types among SIG isolates may be helpful. In this study, it was found that a single isolate (one out of 178 SIG isolates examined) harbored the canine enterotoxin SEC gene. However, the S. intermedius exfoliative toxin gene was found in 166 SIG isolates although the S. aureus-derived exfoliative toxin genes, such as eta, etb and etd, were not detected. SCCmec typing resulted in classifying one isolate as SCCmec type IV, 41 isolates as type V (including three S. intermedius isolates), and 10 isolates as non-classifiable. Genetic relatedness of all S. pseudintermedius isolates recovered from veterinary staff, companion animals, and hospital environments was determined by pulsed-field gel electrophoresis. Strains having the same band patterns were detected in S. pseudintermedius isolates collected at 13 and 18 months, suggesting possible colonization and/or expansion of a specific S. pseudintermedius strain in a veterinary hospital.
[Show abstract][Hide abstract]ABSTRACT: Infectious upper respiratory disease (IURD) of Thoroughbred racehorses has been a frequent problem (29.6% of incidence) at the Seoul Race Park (Korea). Risk factors for IURD include the season with a high transfer rate (summer and fall), the stabling period (≤ 3 months), and age (2 to 3 years old), suggesting that the movement and new environment may have depressed the immune system of the horses and decreased their ability to respond properly to pathogens. The bacterial strains (n = 98) isolated from IURD horses included Pseudomonas spp., Escherichia coli, Staphylococcus spp., Streptococcus equi subsp. equi and zooepidemicus.
Preview · Article · Jun 2011 · Journal of veterinary science (Suwŏn-si, Korea)
[Show abstract][Hide abstract]ABSTRACT: The Staphylococcus intermedius bacterial group (SIG) includes 3 distinct genetically heterogenous species: S. intermedius, S. pseudintermedius, and S. delphini. This pathogen group is associated with many opportunistic skin and ear infections in companion animals. Human infections with S. intermedius and S. pseudintermedius isolates and the emergence of methicillin-resistant isolates have been recently reported, which emphasizes the importance of nationwide identification of SIG isolate prevalence and antibiotic resistance in veterinary clinics. In the present study, a total of 178 SIG isolates were obtained from veterinary staff (n = 40), companion animals (n = 115), and the local environment (n = 23) in 8 Korean veterinary hospitals. Isolates were differentiated into 167 S. pseudintermedius (93.8%) and 11 S. intermedius (6.2%) isolates; S. delphini isolates were not identified. The most effective antibiotics against these isolates included amoxicillin-clavulanic acid, amikacin, nitrofloxacin, imipenem, and vancomycin; whereas ampicillin, penicillin, tetracycline, erythromycin, and trimethoprim-sulfamethoxazole were not effective. Surprisingly, the 128 SIG isolates (71.9%) displayed multiple drug resistance (MDR) against 3 or more antibiotic classes. Out of 52 SIG isolates carrying the methicillin-resistance gene (mecA), only 34 (65.4%) were oxacillin-resistant, and 49 (94.2%) methicillin-resistant SIG were multidrug resistant. This finding suggests the presence of greater numbers of MDR phenotypes than other isolates (P < 0.05).
Full-text · Article · Mar 2011 · Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc
[Show abstract][Hide abstract]ABSTRACT: The antibiotic resistance patterns and prevalence of the transferable tet(O) plasmid were investigated in Campylobacter jejuni and Campylobacter coli isolates from raw chicken, pork, and humans with clinical campylobacteriosis. A total of 180 C. jejuni and C. coli isolates were identified, and the prevalence rates of C. jejuni and C. coli in raw chicken samples were 83% (83 of 100) and 73% (73 of 100), respectively. Twelve percent (6 of 50) and 10% (5 of 50) of pork samples were contaminated with C. jejuni and C. coli, respectively. Disk diffusion susceptibility testing revealed that the most frequently detected resistance was to tetracycline (92.2%), followed by nalidixic acid (75.6%), ciprofloxacin (65.0%), azithromycin (41.5%), ampicillin (33.3%), and streptomycin (26.1%). Of the C. jejuni and C. coli isolates, 65.7% (n=109) contained plasmids carrying the tet(O) gene. Six C. jejuni isolates and two C. coli isolates with high-level resistance to tetracycline (MIC=256 microg/ml) harbored the tet(O) plasmid, which is transferable to other C. jejuni and C. coli isolates. These results demonstrate the presence of an interspecies transferable plasmid containing the tet(O) gene and a high prevalence of antibiotic resistance in Korean Campylobacter isolates and provide an understanding of the antibiotic resistance distribution among Campylobacter species in Korea.
No preview · Article · Aug 2010 · Journal of food protection
[Show abstract][Hide abstract]ABSTRACT: Lantibiotics are small (<5 kDa), polycyclic peptides produced by gram-positive bacteria; they are also known as gram-positive bacteriocins. The high antimicrobial activity of lacticins and the continuing appearance of antibiotic-resistant bacteria in recent years have resulted in a renewed interest in lantibiotics. A partially purified form of lacticin NK34 (a Lactococcus lactis product isolated from the Korean fermented fish jeotgal) was tested to determine its antimicrobial effects against Staphylococcus aureus (n=20) and coagulase-negative Staphylococcus (CNS, n=20) strains isolated from the raw milk of cows with subclinical bovine mastitis in the present study. The spot-on-lawn assay was used to identify the 2 strains from each group with the greatest lacticin NK34 susceptibility, and the minimal lethal dose (MLD) was measured in ICR (imprinting control region) mice. The preventive and therapeutic effects of lacticin NK34 on the mouse infection model were determined for the first time. Lacticin NK34 demonstrated antimicrobial effects in 14 of 20 (70%) S. aureus indicator strains and in 18 of 20 (90%) CNS strains. Staphylococcus aureus 69 and S. simulans 55 demonstrated the greatest susceptibility to lacticin NK34 in the spot-on-lawn assay. The S. aureus 69 MLD was measured at 1.53 x 10(9) cfu/mouse, whereas the S. simulans 55 MLD was 3.59 x 10(9) cfu/mouse. Mice infected experimentally with S. aureus 69 MLD or S. simulans 55 MLD were treated with lacticin NK34. Treated mice demonstrated an 80% survival rate (48 of 60 mice) compared with a survival rate of 7.5% (3 of 40 mice) in control mice treated with distilled water. These data suggest that lacticin NK34 might be useful in the control of bovine mastitis and systemic bacterial infection.
No preview · Article · Aug 2010 · Journal of Dairy Science
[Show abstract][Hide abstract]ABSTRACT: Staphylococcus aureus is a major etiological pathogen of bovine mastitis, which triggers significant economic losses in dairy herds worldwide. In this study, S. aureus strains isolated from the milk of cows suffering from mastitis in Korea were investigated by spa typing and staphylococcal enterotoxin (SE) gene profiling. Forty-four S. aureus strains were isolated from 26 farms in five provinces. All isolates grouped into five clusters and two singletons based on 14 spa types. Cluster 1 and 2 isolates comprised 38.6% and 36.4% of total isolates, respectively, which were distributed in more than four provinces. SE and SE-like toxin genes were detected in 34 (77.3%) isolates and the most frequently detected SE gene profile was seg, sei, selm, seln, and selo genes (16 isolates, 36.3%), which was comparable to one of the genomic islands, Type I nuSabeta. This is a first report of spa types and the prevalence of the recently described SE and SE-like toxin genes among S. aureus isolates from bovine raw milk in Korea. Two predominant spa groups were distributed widely and recently described SE and SE-like toxin genes were detected frequently.
Preview · Article · Jun 2010 · Journal of veterinary science (Suwŏn-si, Korea)
[Show abstract][Hide abstract]ABSTRACT: Staphylococcus intermedius is a common cause of otitis externa, pyoderma and wound infections in companion animals. Although S. intermedius infections are rare in humans, it is zoonotic, with several case reports describing fatal human infections. Presently, we sought to isolate S. intermedius strains from various sources at animal hospitals nationwide in Korea, examine their antibiotic susceptibilities, and determine the possibility of horizontal transmission between animals and humans. Pulsed field gel electrophoresis (PFGE) was used to compare the mecA gene in S. intermedius strains from humans, animals and the environment in animal hospitals. A total of 119 S. intermedius strains were isolated from 529 samples. Using the disk-diffusion method over 90% of the isolates were susceptible to cephalothin, amoxicillin-clavulanic acid, vancomycin, imipenem, nitroflurantoin and amikacin, whereas 97.5% and 98.3% of the isolates were resistant to penicillin and ampicillin, respectively. Among the 39 S. intermedius strains harbouring mecA, similar PFGE patterns were observed between seven isolates from an animal, two isolates from veterinary staff and the environment in one animal hospital, and single isolates from an animal and a veterinarian at another hospital. This result suggests the possibility of horizontal transmission of S. intermedius containing mecA between humans, animals and the environment in animal hospitals and also emphasizes on the importance of S. intermedius with mecA as a possible emerging threat to public health.
No preview · Article · Feb 2010 · Journal of Microbiology and Biotechnology
[Show abstract][Hide abstract]ABSTRACT: Staphylococcus intermedius is a common cause of otitis externa, pyoderma, and wound infections in companion animals. Although S. intermedius infections are rare in humans, it is zoonotic, with several case reports describing fatal human infections. Presently, we sought to isolate S. intermedius strains from various sources at animal hospitals nationwide in Korea, examine their antibiotic susceptibilities, and determine the possibility of horizontal transmission between animals and humans. Pulsed-field gel electrophoresis (PFGE) was used to compare the mecA gene in S. intermedius strains from humans, animals, and the environment in animal hospitals. A total of 119 S. intermedius strains were isolated from 529 samples. Using the disk diffusion method, over 90% of the isolates were found to be susceptible to cephalothin, amoxicillin - clavulanic acid, vancomycin, imipenem, nitroflurantoin, and amikacin, whereas 97.5% and 98.3% of the isolates were resistant to penicillin and ampicillin, respectively. Among the 39 S. intermedius strains harboring mecA, similar PFGE patterns were observed between seven isolates from an animal, two isolates from veterinary staff, and the environment in one animal hospital, and single isolates from an animal and a veterinarian at another hospital. This result suggests the possibility of horizontal transmission of S. intermedius containing mecA between humans, animals, and the environment in animal hospitals and also emphasizes on the importance of S. intermedius with mecA as a possible emerging threat to public health.
No preview · Article · Feb 2010 · Journal of Microbiology and Biotechnology
[Show abstract][Hide abstract]ABSTRACT: Equine respiratory disease is a common cause of poor performance and training interruptions. The higher incidence rate of infectious upper respiratory disease (IURD) in thoroughbred racehorses at the Seoul Race Park coincided with the frequent stabling season, shorter stabling periods, and younger ages in this study. Incidence rates were also correlated with significantly lower proportions of cells expressing MHC class II-, CD2 antigen-, CD4+- or CD8+-T lymphocyte-, and B lymphocyte in IURD patients compared with healthy control groups in the summer and fall and in 2-and-3-year-old groups. The data suggested that movement and new environments may have resulted in immunosuppression and inappropriate responses to respiratory pathogens in IURD patients. The IURD incidence decreased with age, perhaps by the acquisition of immunity, and study results suggested that immunologic protection was associated with IURD, particularly in young thoroughbred racehorses. Streptococci isolates were identified in 11 of 72 IURD horses, and 3 of these isolates were identified as Streptococcus. equi subsp. equi. S. equi subsp. zooepidemicus was isolated from 2 of 23 IURD horses in the spring (8.7%), 5 of 23 in the summer (21.7%), and 1 of 6 in winter (16.7%). S. equi subsp. zooepidemicus (5%) was also identified in 3 of 61 isolates from clinically normal horses. Racetracks should implement anti-IURD protective measures by assessing the capacity of equine immunologic protection at the Park and by limiting the introduction of specific respiratory pathogens (such as S. equi subsp. equi) by preventing the access of infected horses with a respiratory pathogen-free certification system prior to Park entry.
Preview · Article · Sep 2009 · Journal of Microbiology and Biotechnology
[Show abstract][Hide abstract]ABSTRACT: Adipose tissue-derived mesenchymal stem cells (AD-MSCs), which can differentiate into several lineages, have immunomodulatory properties similar to those of bone marrow-derived MSCs. However, the specific mechanism by which the immunomodulatory effect of MSCs occurs is not clear. In this study, we isolated canine AD-MSCs (cAD-MSCs) and induced their development into adipocyte, osteocyte, and neuron-like cells. We then investigated their phenotype and cytokine expression to determine whether they were able to exert an immunomodulatory effect and what the underlying mechanisms of this effect were. cAD-MSCs expressed CD44, CD90, and MHC class I and were also partially positive for the expression of CD34; however, they did not express CD14 and CD45. In addition, they expressed the mRNA of transforming growth factor beta (TGF-β), IL-6, IL-8, CCL2, CCL5, vascular endothelial growth factor, hepatocyte growth factor (HGF), tissue inhibitor metalloproteinase-1/2, and cyclooxygenase-2 but not that of IL-10. Further, leukocyte proliferation induced by mitogens was suppressed when they were cocultured with irradiated cAD-MSCs, as well as with culture supernatants of cAD-MSCs alone. Moreover, TNF-α production significantly decreased, whereas TGF-β, IL-6, and interferon-γ production significantly increased in cAD-MSCs that were cocultured with leukocytes. Finally, immonomodulatory factors of MSCs, such as TGF-β, HGF, prostaglandin E2 (PGE2), and indoleamine 2, 3 dioxygenase (IDO), increased significantly in cAD-MSCs that were cocultured with leukocytes; however, the production of PGE2 and IDO showed different kinetics, and leukocyte proliferation was effectively restored by PGE2 and IDO inhibitors. Taken together, these results indicate that the immunomodulatory effects of cAD-MSCs are associated with soluble factors (TGF-β, HGF, PGE2, and IDO). Therefore, it is suggested that cAD-MSCs have a potential therapeutic use in the treatment of immune-mediated disease.
Full-text · Article · Sep 2008 · Stem cells and development
[Show abstract][Hide abstract]ABSTRACT: We sought to test two concepts: that nanoparticles can be used for in vivo gene delivery and that canine granulocyte-macrophage colony-stimulating factor (GM-CSF)/nanoparticles can have possibility to be used to treat transient (acute) canine leukopenia.
We have generated a novel fluorescent-silica nanoparticle binding of canine GM-CSF gene; canine GM-CSF gene was inserted between the cytomegalovirus promoter and poly-adenylation sequences of simian virus 40, and the gene construct was ligated to fluorescent silica nanoparticles functionalized with tertiary amine.
When the GM-CSF/nanoparticles were injected into normal dogs, the GM-CSF was expressed in peripheral blood mononuclear cells for at least 9 days and there were significant increases in white blood cell counts, as confirmed by complete blood count, differential count, and flow cytometry. Significant increases in expression of major histocompatibility complex class II on granulocytes and in serum GM-CSF were also observed. Readministration of the nanoparticles was also effective and expression in various tissues was confirmed by reverse transcriptase polymerase chain reaction.
These GM-CSF/nanoparticles may be useful for correction of acute leukopenia, such as chemotherapy-induced myelosuppression without developing neutralizing antibodies.
Preview · Article · Aug 2008 · Experimental Hematology
[Show abstract][Hide abstract]ABSTRACT: Our previous study has shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) gene/silica nanoparticles have a leukocytosis effect in normal dogs. Therefore, this study was conducted to determine whether treatment of canine GM-CSF gene/silica nanoparticles has preventive or therapeutic effects in dogs with leukopenia.
To induce leukopenia, vinblastine was administered intravenously at a dose of 2 mg/m(2) of body surface area on day 0. Then 7.5 microg GM-CSF/nanoparticles (1:100, w/w) were administered intravenously to each of four dogs in the prevention group on day 2 and an equivalent amount of GM-CSF/nanoparticles was administered to the post-nadir group on day 4 (other groups were administered phosphate-buffered saline intravenously).
Therapeutic GM-CSF gene was expressed in peripheral blood mononuclear cells for 10 days and both the prevention and post-nadir groups showed significant increases in white blood cell counts when compared with the control group, as confirmed by complete blood count, differential count, and flow cytometry.
GM-CSF/nanoparticles can be useful for correction of acute leukopenia, such as chemotherapy-induced myelosuppression, without developing neutralizing antibodies.
No preview · Article · Jul 2008 · Experimental Hematology
[Show abstract][Hide abstract]ABSTRACT: The antibacterial effect and mechanism of action of a silver ion solution that was electrically generated were investigated
for Staphylococcus aureus and Escherichia coli by analyzing the growth, morphology, and ultrastructure of the bacterial cells following treatment with the silver ion solution.
Bacteria were exposed to the silver ion solution for various lengths of time, and the antibacterial effect of the solution
was tested using the conventional plate count method and flow cytometric (FC) analysis. Reductions of more than 5 log10 CFU/ml of both S. aureus and E. coli bacteria were confirmed after 90 min of treatment with the silver ion solution. Significant reduction of S. aureus and E. coli cells was also observed by FC analysis; however, the reduction rate determined by FC analysis was less than that determined
by the conventional plate count method. These differences may be attributed to the presence of bacteria in an active but nonculturable
(ABNC) state after treatment with the silver ion solution. Transmission electron microscopy showed considerable changes in
the bacterial cell membranes upon silver ion treatment, which might be the cause or consequence of cell death. In conclusion,
the results of the present study suggest that silver ions may cause S. aureus and E. coli bacteria to reach an ABNC state and eventually die.
Full-text · Article · May 2008 · Applied and Environmental Microbiology
[Show abstract][Hide abstract]ABSTRACT: Staphylococcus aureus is one of the main etiological agents of bovine mastitis; however, antibiotics that are effective against bovine strains of S. aureus are not currently available. Staphylococcal enterotoxin type C (SEC), a superantigen, is the enterotoxin most frequently expressed by bovine strains of S. aureus and one of immunogenic determinants. The purpose of this study was to evaluate the protective effectiveness of recombinant SEC mutant vaccine (MastaVactrade mark) against experimentally induced bovine infection. Three representative SEC secreting strains were selected from 9 candidate isolates that showed various intensities of pathogenicity on mice and inoculated into 5 lactating dairy cattle at a concentration of 50-5.0x10(8) CFU per quarter. The optimal experimental bovine subclinical mastitis model was produced by inoculation with 50 CFU of S. aureus 409 per quarter, a level which was not lethal to mice. After the experimental model was determined, other 3 cattle were intramuscularly administered three doses of vaccine at day 0, at 2 wks and at 6 wks. Nine quarters of 3 vaccinated cattle and 8 quarters of 3 control cattle were then challenged with S. aureus 409. An SEC-specific ELISA test conducted at 4 wks post-immunization confirmed the presence of a high antibody titer against SEC in all vaccinated cattle. The somatic cell counts from the vaccinated group remained relatively low, whereas those of control group increased significantly after challenge with S. aureus. After challenge, S. aureus was not isolated from any cattle in the vaccinated group, whereas it was isolated from 75% of the cattle in the control group. These results indicate that recombinant SEC mutant vaccine had a protective effect against S. aureus intramammary infection in lactating cattle.
[Show abstract][Hide abstract]ABSTRACT: Bovine mastitis can be diagnosed by abnormalities in milk components and somatic cell count (SCC), as well as by clinical signs. We examined raw milk in Korea by analyzing SCC, milk urea nitrogen (MUN), and the percentages of milk components (milk fat, protein, and lactose). The associations between SCC or MUN and other milk components were investigated, as well as the relationships between the bacterial species isolated from milk. Somatic cell counts, MUN, and the percentages of milk fat, protein, and lactose were analyzed in 30,019 raw milk samples collected from 2003 to 2006. The regression coefficients of natural logarithmic-transformed SCC (SCCt) on milk fat (-0.0149), lactose (-0.8910), and MUN (-0.0096), and those of MUN on milk fat (-0.3125), protein (-0.8012), and SCCt (-0.0671) were negative, whereas the regression coefficient of SCCt on protein was positive (0.3023). When the data were categorized by the presence or absence of bacterial infection in raw milk, SCCt was negatively associated with milk fat (-0.0172), protein (-0.2693), and lactose (-0.4108). The SCCt values were significantly affected by bacterial species. In particular, 104 milk samples infected with Staphylococcus aureus had the highest SCCt (1.67) compared with milk containing other mastitis-causing bacteria: coagulase-negative staphylococci (n = 755, 1.50), coagulase-positive staphylococci (except Staphylococcus aureus; n = 77, 1.59), Streptococcus spp. (Streptococcus dysgalactiae, n = 37; Streptococcus uberis, n = 12, 0.83), Enterococcus spp. (n = 46, 1.04), Escherichia coli (n = 705, 1.56), Pseudomonas spp. (n = 456, 1.59), and yeast (n = 189, 1.52). These results show that high SCC and MUN negatively affect milk components and that a statistical approach associating SCC, MUN, and milk components by bacterial infection can explain the patterns among them. Bacterial species present in raw milk are an important influence on SCC in Korea.
Preview · Article · Jan 2008 · Journal of Dairy Science
[Show abstract][Hide abstract]ABSTRACT: Staphylococcal food poisoning is caused by enterotoxin-producing Staphylococcus aureus. We investigated the prevalence of such organisms in samples of bovine mastitic milk (n = 714), raw meat (n = 139), and vegetables (n = 616). We determined the degrees of relatedness of isolates as indicated by antibiogram, staphylococcal enterotoxin (SE) productivity, and coagulase gene restriction fragment length polymorphism analysis. We examined 297 S. aureus isolates and found SE production in 57 (31.8%), 4 (7.8%), and 49 (73.1%) isolates from raw milk, raw meat, and vegetables, respectively. A high proportion of the isolates obtained from milk produced more than two types of toxins (mainly SEA, SEB, and/or SEC), whereas isolates from raw meat and vegetables primarily produced SEA alone. Most isolates were sensitive to cephalothin (97.6%), gentamicin (80.8%), erythromycin (79.5%), and tetracycline (72.7%), but were resistant to penicillin (90.2%) and ampicillin (88.9%). The proportion of antibiotic-resistant isolates differed according the source of the bacteria; the milk and vegetable isolates were more resistant to penicillin and ampicillin than were the meat isolates (P < 0.05), whereas tetracycline resistance was limited to the milk and vegetables isolates. The coagulase genotypes (I to XII) varied with the source of the organism, and only a few genotypes prevailed in each source: II (42.4%) and IV (24%) types in isolates from milk, IX (35.3%) and XI (45%) from raw meat, and III (40.3%) and XII (32.8%) from vegetables. These findings suggest that remarkable differences exist in antibiogram, SE productivity, and coagulase genotypes, resulting in limited clonal transmission of S. aureus into various food sources. As enterotoxin production only occurs when S. aureus grows to high numbers, staphylococcal food poisoning can be prevented by proper refrigeration.
Full-text · Article · Dec 2007 · Journal of food protection
[Show abstract][Hide abstract]ABSTRACT: Campylobacter species are one of the most common causes of bacterial diarrhea in humans worldwide. The consumption of foods contaminated with two Campylobacter species, C. jejuni and C. coli, is usually associated with most of the infections in humans. In this study, a rapid, reliable, and sensitive multiplex real-time quantitative PCR was developed for the simultaneous detection, identification, and quantification of C. jejuni and C. coli. In addition, the developed method was applied to the 50 samples of raw chicken meat collected from retail stores in Korea. C. jejuni and C. coli were detected in 88 and 86% of the samples by real-time quantitative PCR and the conventional microbiological method, respectively. The specificity of the primer and probe sets was confirmed with 30 C. jejuni, 20 C. coli, and 35 strains of other microbial species. C. jejuni and C. coli could be detected with high specificity in less than 4 h, with a detection limit of 1 log CFU/ml by the developed real-time PCR. The average counts (log CFU per milliliter) of C. jejuni or C. coli obtained by the conventional methods and by the real-time PCR assay were statistically correlated with a correlation coefficient (R2) between 0.73 and 0.78. The real-time PCR assay developed in this study is useful for screening for the presence and simultaneous differential quantification of C. jejuni and C. coli.
Preview · Article · Oct 2007 · Journal of food protection
[Show abstract][Hide abstract]ABSTRACT: Based on our previous study evaluating the in vivo cure efficacy of chitosan on bovine mastitis, a more water-soluble chitosan-oligosaccharide (OCHT) with a high degree of deacetylation and low molecular weight was prepared to obtain high antibiotic efficacy. The growth of Staphylococcus aureus isolated from bovine mastitis was inhibited within 10 min of treatment with OCHT in concentrations ranging from 0.0001 to 0.5%. Additionally, electron microscopic observation indicated that the surface of the OCHT-treated bacteria was expanded, distorted, and lysed compared to that of the control bacteria. In mice, the proportion of monocytes was elevated, and the levels of interleukin-6 and interferon-gamma sharply increased l h after the peritoneal inoculation of the OCHT (0.5 to 1 mg per mouse). Mice challenged intraperitoneally with S. aureus (2.5 x 10(8) colony forming units) after oral treatment with OCHT (0.5 to 2 mg per day) for 7 days showed a higher survival rate (70-100%) than that of the control (10%). We suggest that the OCHT prepared in this study is a potential agent for the prevention and treatment of bovine mastitis based on its strong antibacterial activity against S. aureus as well as the immunostimulative effect it exhibits on murine infection by S. aureus.
Full-text · Article · Aug 2007 · Applied Microbiology and Biotechnology
[Show abstract][Hide abstract]ABSTRACT: An anti-fungal efficacy test of the silver laundry machine, which electrically generates silver ions, was carried out against four fungi--Trichophyton rubrum, Candida albicans, Microsporum canis and Aspergillus flavus--which cause major fungal infection in humans and animals. Compared with the conventional laundry machine, washing with the silver laundry machine regardless of detergent use was effective against most of the fungi with about 4 log(10) (CFU ml(-1)) reduction and eliminated almost all the fungi when using the detergent. Moreover, the cleaning activity of the silver laundry machine with detergent was higher than that of the conventional laundry machine with detergent both after wash and after final spin step against all four examined fungi. The silver laundry machine may be useful in preventing skin irritation caused by fungi-contaminated fabric in the hospital and in the home.