• Journal of Microbiology
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• v.45 no.5
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• pp.453-459
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• 2007

We developed a multiplex PCR (mPCR) assay to simultaneously detect Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Ureaplasma urealyticum, Corynebacterium spp. and seudomona aeruginosa. This method employs a single tube and multiple specific primers which yield 200, 281, 346, 423, 542, and 1,427 bp PCR products, respectively. All the PCR products were easily detected by agarose gel electrophoresis and were sequenced to confirm the specificity of the reactions. To test this method, DNA extracted from urine samples was collected from 96 sexually transmitted disease or prostatitis patients at a local hospital clinical center, and were subjected to the mPCR assay. The resulting amplicons were cloned and sequenced to exactly match the sequences of known pathogenic isolates. N. gonorrhoeae and Corynebacterium spp. were the most frequently observed pathogens found in the STDs and prostatitis patients, respectively. Unexpectedly, P. aeruginosa was also detected in some of the STD and prostatitis samples. More than one pathogen species was found in 10% and 80.7% of STD and prostatitis samples, respectively, indicating that STD and prostatitis patients may have other undiagnosed and associates. The sensitivity of the assay was determined by sing purified DNA from six pathogenic laboratory strains and revealed that this technique could detect pathogenic DNA at concentrations ranging from 0.018 to $1.899\;pg/{\mu}l$. Moreover, the specificities of this assay were found to be highly efficient. Thus, this mPCR assay may be useful for the rapid diagnosis of causative infectious STDs and prostatitis. useful for the infectious STDs and prostatitis.

• Korean Journal of Veterinary Service
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• v.34 no.3
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• pp.217-226
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• 2011

Salmonella spp. is of increasing public health concern as causative pathogens of food poisoning. The aim of this study was to investigate the serotypes and antimicrobial resistance pattern of Salmonella spp. isolated from duck farms in Daegu-Gyeongbuk province. Also, S. Enteritidis and S. Typhimurium isolates were further examined for plasmid analysis, phage typing and pulsed-field gel electrophoresis (PFGE). A total of 34 Salmonella spp. (16.4%) were isolated from duck farms and ten serotypes were identified. The predominant serotypes were S. Typhimurium (23.5%) S. Fyris (17.6%) and S. Haardt (11.8%), S. Agona and S. Enteritidis (respectively 8.8%). Of 34 Salmonella isolates, 15 (44.1%) isolates were resistant to at least one antimicrobial agent and multiple resistance (resistance to more than 4 drugs) was observed in 9 strains (26.5%). The high resistance was found to streptomycin (32.4%), tetracycline (29.4%), ampicillin, kanamycin and nalidixic acid (respectively, 26.5%), all Salmonella isolates were susceptible to cefoxitin, cefotaxime, gentamicin, amikacin and ciprofloxacin. All S. Enteritidis and S. Typhimurium isolates were found to contain only one plasmid (ca. 54 or 55kb, respectively). Among the S. Enteritidis isolates, two phage types were found, PT32a and PT1c, respectively, one isolates did not react with any of the phages used. Whereas, all S. Typhimurium isolates were RDNC (reacts but does not conform). PFGE showed to be a useful typing method better than plasmid analysis and phage typing for discrimination of isolates especially, S. Typhimurium isolates. Our results indicated that the serotypes of Salmonella isolates are widely distributed in duck farms, further epidemiological studies should be carried out.

• Journal of Animal Science and Technology
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• v.65 no.2
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• pp.441-458
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• 2023

The poultry industry, which produces excellent sources of protein, suffers enormous economic damage from diseases. To solve this problem, research is being conducted on the early detection of infection according to the behavioral characteristics of poultry. The purpose of this study was to evaluate the potential of a non-movement behavior observation method to detect sick chickens. Forty 1-day-old Ross 308 males were used in the experiments, and an isolator equipped with an Internet Protocol (IP) camera was fabricated for observation. The chickens were inoculated with Salmonella enterica serovar Gallinarum A18-GCVP-014, the causative agent of fowl typhoid (FT), at 14 days of age, which is a vulnerable period for FT infection. The chickens were continuously observed with an IP camera for 2 weeks after inoculation, chickens that did not move for more than 30 minutes were detected and marked according to the algorithm. FT infection was confirmed based on clinical symptoms, analysis of cardiac, spleen and liver lesion scores, pathogen re-isolation, and serological analysis. As a result, clinical symptoms were first observed four days after inoculation, and dead chickens were observed on day six. Eleven days after inoculation, the number of clinical symptoms gradually decreased, indicating a state of recovery. For lesion scores, dead chickens scored 3.57 and live chickens scored 2.38. Pathogens were re-isolated in 37 out of 40 chickens, and hemagglutination test was positive in seven out of 26 chickens. The IP camera applied with the algorithm detected about 83% of the chickens that died in advance through non-movement behavior observation. Therefore, observation of non-movement behavior is one of the ways to detect infected chickens in advance, and it appears to have potential for the development of remote broiler management system.

• Clinical and Experimental Pediatrics
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• v.48 no.6
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• pp.619-623
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• 2005

Purpose : Bacteremia in immunocompromised pediatric cancer patients can lead to high morbidity and mortality, if not treated early and properly. The incidence and antibiotic sensitivities to common pathogens of bacteremia in pediatric cancer patients are liable to change, according to region and time. We investigated the causative organisms and antibiotic sensitivities of bacteremia in pediatric cancer patients to assess the adequacy of empiric antimicrobial therapy. Methods : From September 1995 to August 2003, we retrospectively evaluated 58 episodes in 39 pediatric cancer patients with bacteremia treated at the Pediatric Department of Yeungnam University Hospital. We investigated and analyzed the causative organisms and the antibiotic sensitivity test results by reviewing the records of the microbiologically proven positive blood culture results. Results : The incidence of bacteremia in pediatric cancer patients in this study was 5.7 percent (58 episodes out of 1,022 occasions of blood cultures). Gram-positive organisms were isolated more often than gram-negative organisms (63.8 percent vs 36.2 percent) in the following order : Staphylococcus epidermidis (37.9 percent), Staphylococcus aureus (17.3 percent), Escherichia coli (12 percent), Streptococcus (8.6 percent), Enterobacter (6.9 percent), Klesiella (6.9 percent), Serratia (3.5 percent), Acinetobacter (3.5 percent), Proteus (1.7 percent) and Morganella morganii (1.7 percent). In antibiotic sensitivity tests, only six of 37 isolates (16 percent) of gram positive bacteria were sensitive to penicillin and 15 of 37 isolates (40 percent) were sensitive to oxacillin. All except one Staphylococcus aureus were sensitive to vancomycin and all except one Staphylococcus epidermidis were sensitive to teicoplanin among 37 isolates of gram positive bacteria. In the case of gram negative bacteria, two of 21 isolates (10 percent) and four of 21 isolates (19 percent) were sensitive to cefotaxime and ceftazidime, respectively. Only six of 21 isolates (29 percent) were sensitive to aminoglycoside, but all 21 isolates (100 percent) were sensitive to imipenem. All seven isolates tested after the year 2000 were sensitive to meropenem. Conclusion : In conclusion, we should choose the proper antimicrobials in treating pediatric cancer patients with suspected bacteremia, reflecting the increasing episodes of gram positive bacteremia and polymicrobial resistance of gram positive and negative organisms.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.139-145
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• 2003

The purpose of this study was to investigate the awareness and practice of Korean consumer on food safety. A telephone survey was conducted from 1,040 adults randomly selected from each province and large city of Korea. Therefore, 12.4% of the subjects experienced foodborne illness at least once a year and 0.3% was hospitalized due to the illness. General restaurant (37.2%) and home (21.2%) were the main causative place of foodborne illness, and the most frequently associated foods were meat and meat products (41.7%) and fish and fish products (18.7%). Regarding the causative agent of foodborne illness, the respsondents were aware of Cholera (75.5%), Vibrio gastroenteritis (73%), Shigellosis (65.5%), Bacillary dysentery (65.5%) and Salmonellosis (47.5%) very well; however very few were aware of Listeriosis (9.9%) and brucellosis (8.3%) and ever believed they were not food-related illness. When the survey data were analyzed based on 3 models (Model 1: Knowledge about the pathogens associated food and water, Model 2: The awareness of food safety, Model 3: Attitudes and behavior about foodborne disease prevention and measure) by Multiple regression analysis. The results showed that the awareness of the causative agent of foodborne illness was significantly related with the previous experience of foodborne illness (OR: 1.714) followed by education level (OR: 0.536) and married status (OR: 0.527). The awareness of food safety was significatly related with education level (OR: 0.702). Education (OR: 0.816) and gender (OR:0.650) were the main factors affecting the awareness of the practice to prevent foodborne illness. However, the previous experience of foodborne illness and food safety education, and the awareness of food safety did not show any correlation, suggesting that the experience and awareness of foodborne illness do not affect the real practice of food safety.

• Tuberculosis and Respiratory Diseases
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• v.83 no.1
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• pp.81-88
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• 2020

Background: Use of appropriate antibiotics for the treatment of pneumonia is integral in patients admitted to intensive care units (ICUs). Although it is recommended that empirical treatment regimens should be based on the local distribution of pathogens in patients with suspected hospital-acquired pneumonia, few studies observe patients admitted to ICUs with nursing home-acquired pneumonia (NHAP). We found factors associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via the emergency room (ER). Methods: We performed a retrospective cohort study of 83 pneumonia patients with confirmed causative bacteria admitted to ICUs via ER March 2015-May 2017. We compared clinical parameters, between patients who received appropriate or inappropriate antibiotics using the Mann-Whitney U, Pearson's chi-square, and Fisher's exact tests. We investigated independent factors associated with inappropriate antibiotic use in patients using multivariate logistic regression. Results: Among 83 patients, 30 patients (36.1%) received inappropriate antibiotics. NHAP patients were more frequently treated with inappropriate antibiotics than with appropriate antibiotics (47.2% vs. 96.7%, p<0.001). Methicillin-resistant Staphylococcus aureus was more frequently isolated from individuals in the inappropriate antibiotics-treated group than in the appropriate antibiotics-treated group (7.5% vs. 70.0%, p<0.001). In multivariate analysis, NHAP was independently associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via ER. Conclusion: NHAP is a risk factor associated with the use of inappropriate antibiotics in patients with pneumonia admitted to the ICU via the ER.

• Journal of Korean society of Dental Hygiene
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• v.18 no.5
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• pp.831-842
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• 2018

Objectives: This study was conducted to reveal the biological basis of dental plaque and preschool children's dental health status through repetitive and continuous toothbrushing instruction to preschool children, using quantitative criteria, and to emphasize the importance of the role of an oral health manager for the prevention of dental caries. Methods: After IRB approval, toothbrushing instruction and oral microbial specimen collection were conducted with children of preschool age at the Daycare Center attached to D. University, Busan. Specimens from 27 children were characterized by analysis with real-time multi-chain enzymatic polymerization reaction technique at an agency specializing in genetic analysis. Results: In a survey of the children's dental health behaviors, 48.1% responded that the toothbrushing time is 91 to 150 seconds; 66.7% responded that the frequency of toothbrushing is more than three times per day; 81.5% stated that they performed tongue brushing; and 81.5% brushed their teeth. Regarding levels of dental cariogenic bacteria, after children received continuous toothbrushing instruction, there were reductions in both Streptococcus mutans and Streptococcus sobrinus. Regarding toothbrushing time, the time increased in relation to the presence of instruction. Regarding Quigley Hein Index, the index decreased in the early and middle periods upon addition of instruction, then increased in the middle and later periods. Conclusions: Through persistent and repetitive toothbrushing instruction, healthy behavior can be positively established in children of preschool age; it is necessary to prepare institutional measures so opportunities for dental health education can be consistently provided and maintained. In the future, it will be necessary to conduct a follow-up study to verify the factors affecting toothbrushing time and volume of oral pathogens.

• The Journal of Korean Society of Virology
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• v.29 no.4
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• pp.247-259
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• 1999

Small round structured viruses (SRSV) are the major ethological agents which can cause outbreaks of non-bacterial gastroenteritis or food poisoning both in children and adults. The classification of family Caliciviridae to which SRSV belong, is based on the genome encoding three open reading frames. The rotavirus is another major pathogen which causes diarrhea in young children. We examined stool specimens obtained from diarrheal patients in Wonju from which bacterial pathogens were not found. To detect causative viruses from stool specimens of patients, reverse transcription (RT)-polymerase chain reaction (PCR) or nested PCR using rotavirus or SRSV specific primers was performed. In this study, RT-nested PCR procedure which can amplify a 330 bp fragment derived from RNA dependent RNA polymerase (RDRP) region within ORF1 was applied for the detection of SRSV. For the detection of rotaviruses, a 877 bp fragment from the VP4 region of rotavirus genome was amplified. As a result, rotavirus was not detected while SRSV sequences were detected from one out of five specimens. The nucleotide and amino acid sequences of the Wonju isolate were compared with other 6 Korean isolates which have been isolated and sequenced in our laboratory. Sequence analysis revealed that the Wonju isolate was rather distinct from other Korean isolates: the Wonju isolate was closer to genogroup I of SRSV while other 6 Korean isolates belonged to genogroup II.

• Korean Journal of Microbiology
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• v.44 no.4
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• pp.305-310
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• 2008

Staphylococcus aureus is one of the most significant pathogens and a causative agents of nosocomial infections. The emergence of methicillin resistant S. aureus (MRSA), in particular, has become a major clinical and epidemiological problems worldwide. In this study, we analyzed the toxin genes and investigated molecular epidemiological characteristics of S. aureus isolated from stools of diarrheal patients at the hospitals in Incheon. Of the 609 strains from 2,281 specimens, 173 strains retained enterotoxin; 68 isolates (39.30%), 100 isolates (57.80%) were classified to A and C type, respectively. In the antibiotic susceptibility, all of enterotoxin positive isolates were resistant to oxacillin. Eighty eight strains (50.86%) of 173 MRSA isolate possessed tsst gene, but eta and eth genes were not detected at all. In the detection of MRSA associated genes by PCR method, mecA genes were detected in 167 strains (96.53%). From the result of PFGE analysis, we classified tsst-positive MRSA to 10 types and 24 subtypes. Type A, H and F were the major strains comprised of 57.95% (51 strains), 10.22% (9 strains) and 9.09% (8 strains) respectively.

• Journal of Microbiology and Biotechnology
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• v.31 no.5
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• pp.667-675
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• 2021

Streptococcus agalactiae is an important bacterial pathogen and causative agent of diseases including neonatal sepsis and meningitis, as well as infections in healthy adults and pregnant women. Although antibiotic treatments effectively relieve symptoms, the emergence and transmission of multidrug-resistant strains indicate the need for an effective immunotherapy. Effector T helper (Th) 17 cells are a relatively newly discovered subpopulation of helper CD4⁺ T lymphocytes, and which, by expressing interleukin (IL)-17A, play crucial roles in host defenses against a variety of pathogens, including bacteria and viruses. However, whether S. agalactiae infection can induce the differentiation of CD4⁺ T cells into Th17 cells, and whether IL-17A can play an effective role against S. agalactiae infections, are still unclear. In this study, we analyzed the responses of CD4⁺ T cells and their defensive effects after S. agalactiae infection. The results showed that S. agalactiae infection induces not only the formation of Th1 cells expressing interferon (IFN)-γ, but also the differentiation of mouse splenic CD4⁺ T cells into Th17 cells, which highly express IL-17A. In addition, the bacterial load of S. agalactiae was significantly increased and decreased in organs as determined by antibody neutralization and IL-17A addition experiments, respectively. The results confirmed that IL-17A is required by the host to defend against S. agalactiae and that it plays an important role in effectively eliminating S. agalactiae. Our findings therefore prompt us to adopt effective methods to regulate the expression of IL-17A as a potent strategy for the prevention and treatment of S. agalactiae infection.