BACKGROUND: Clostridium difficile is one of the most important pathogens responsible for nosocomial diarrhea. Recently, we have frequently experienced culture positive, toxin A enzyme immunoassay negative strains. Therefore, we evaluated the strains with several PCR primer sets to characterize them. METHODS: A total of 351 stool specimens were examined for toxin A using enzyme linked fluorescent immunoassay (ELFA) and also cultured for C. difficile using cycloserine cefoxitine fructose agar incubated under anaerobic conditions. Spore stain and Vitek ANA identification card (BioMerieux, France) were used for identification of C. difficile. We amplified toxin A and toxin B genes in 81 isolates using primers NK1- NK2, NK3-NK2, NK9- NK11, and NK104-NK105. RESULTS: The concordance rate between ELFA and culture was 65.2% (229/351). PCR for the toxin A gene using NK1-NK2, NK3-NK2 and for the toxin B gene using NK104-NK105 showed almost the same results. However, toxin A gene PCR using NK9-NK11 showed that 45.7% (37/81) of the evaluated strains were toxin A (-)/ toxin B(+) variant strains; thus, the corrected sensitivity and specificity of the ELFA based on the PCR results for toxin A and B genes were 65.6% and 100%, respectively. CONCLUSIONS: The low sensitivity of the ELFA results for toxin A was due to the toxin A(-)/toxin B(+) variants of C. difficile, suggesting that the prevalence of the variant strains could be higher in Korea than was expected.
Agar ; Cefoxitin ; Clostridium difficile* ; Clostridium* ; Cycloserine ; Diarrhea ; Fructose ; Genes, vif ; Immunoassay ; Immunoenzyme Techniques ; Korea ; Polymerase Chain Reaction ; Prevalence ; Sensitivity and Specificity ; Spores

In Korea, the majority of imported malaria cases are Plasmodium vivax and P. falciparum, but Plasmodium ovale cases are rarely reported. We describe an imported case of P. ovale that was confirmed by peripheral blood smear and nested PCR targeting the small subunit ribosomal RNA (SSU rRNA) gene. A 37-yr-old male had visited the Republic of Ghana in tropical West Africa 3 months ago, and suffered from fever and headache since 2 weeks after his return to Korea. The results of rapid malaria test using SD Malaria Antigen/Antibody Kit (Standard Diagnostics, Korea) were negative, but Plasmodium species was observed in Wright-Giemsa-stained peripheral blood smear. For the evaluation of possible mixed infection and identification of species, we performed a nested PCR targeting the SSU rRNA gene. P. ovale single infection was confirmed by PCR. The sequence analysis of the P. ovale SSU rRNA gene showed that our isolate was P. ovale classic type. We should confirm P. ovale infection for an accurate diagnosis and treatment of imported malaria cases in Korea because the number of travelers to P. ovale-endemic regions has recently increased.
Africa, Western ; Coinfection ; Fever ; Genes, rRNA ; Ghana ; Headache ; Humans ; Korea ; Malaria ; Male ; Plasmodium ; Plasmodium ovale ; Plasmodium vivax ; Polymerase Chain Reaction ; RNA, Ribosomal ; Sequence Analysis

BACKGROUND: We intended to evaluate the diagnostic usefulness of a multiplex reverse transcriptase- PCR (mRT-PCR) assay kit under dual priming oligonucleotide system (DPO) for the childhood acute respiratory tract infections. METHODS: Two hundred nasopharyngeal aspirates were taken from children < or = 5 yr old admitted due to acute respiratory infections in 2004. Direct fluorescent antibody (FA) assays were performed with fresh specimens; then, mRT-PCRs for the detection of 12 respiratory viruses (Seeplex RV detection kit, SeeGene, Seoul, Korea) were tested with frozen specimens. RESULTS: FA assays for five common respiratory viruses showed positive results in 66 patients (33.0%), while mRT-PCR detected causative viruses in 112 patients (56.0%), including 16 co-infected cases (8.0%). A total of 129 viruses were identified: respiratory syncytial virus A/B (38.0%/7.8%), influenza virus A/B (10.1%/5.4%), parainfluenza virus 1/2/3 (7.0%/3.1%/7.8%), coronavirus 229E or NL63 (6.2%), human metapneumovirus (4.7%), adenovirus (4.7%), rhinovirus (3.9%), and coronavirus OC43 (1.6%). CONCLUSIONS: DPO-based mRT-PCR was found as a sensitive tool for the detection of the viruses that cause childhood respiratory infections. Clinical significances of the agents detected by mRTPCR need further evaluations.
Child, Preschool ; DNA, Viral/analysis ; Fluorescent Antibody Technique, Direct ; Humans ; Infant ; Infant, Newborn ; Oligonucleotide Probes ; Reproducibility of Results ; Respiratory Tract Infections/*diagnosis/epidemiology/virology ; Reverse Transcriptase Polymerase Chain Reaction/*methods ; Virus Diseases/*diagnosis/epidemiology/virology ; Viruses/genetics/*isolation & purification

BACKGROUND: The aim of this study is to clarify the epidemiology of swine-origin influenza A (H1N1) virus 2009 (S-OIV) during the first month of outbreak at one of influenza clinic in Seoul, Korea. METHODS: We documented the epidemiologic and clinical features of S-OIV-confirmed cases who visited a university hospital in Northeastern Seoul between August 21 and September 20, 2009. Nasopharyngeal swab of patients with acute febrile respiratory illnesses were evaluated with rapid influenza antigen tests and multiplex RT-PCR for S-OIV and seasonal influenza A. RESULTS: A total of 5,322 patients with acute febrile respiratory illnesses were identified at our influenza clinic for the study period. S-OIV was confirmed in 309 patients by RT-PCR. The patients ranged from 2 months to 61 years of age and 189 patients (61.2%) were teenagers. Eighty-one patients had known contact with S-OIV-confirmed patients in schools (N=61), households (N=15), and healthcare facilities (N=3). Frequent symptoms were fever (94.5%), cough (73.1%), sore throat (52.1%), and rhinorrhea (50.5%). Gastrointestinal symptoms were also present in 10 patients (4.9%). Ten patients (4.9%) required hospitalizations. Seventy patients (22.7%) could not take oseltamivir at the first visits, however, all of them recovered without complication. Rapid antigen tests showed the sensitivity of 44.4% (130/294). Patients with positive antigen tests, compared with negative antigen tests, showed higher frequencies of rhinorrhea (60.8% vs 43.3%, P=0.004) and stuffy nose (33.8% vs 20.1%, P=0.012). CONCLUSION: S-OIV infections spread predominately in school-aged children during the early accelerating phase of the outbreak. Rapid influenza antigen tests were correlated with nasal discharge and obstruction.
Adolescent ; Child ; Cough ; Delivery of Health Care ; Family Characteristics ; Fever ; Hospitalization ; Humans ; Influenza A virus ; Influenza, Human ; Korea ; Nose ; Oseltamivir ; Pharyngitis ; Seasons ; Viruses