Evaluation of Peptide Nucleic Acid Probe-based Real-time PCR for Detection of Mycobacterium tuberculosis Complex and Nontuberculous Mycobacteria in Respiratory Specimens

BACKGROUND: A peptide nucleic acid (PNA) probe-based real-time PCR (PNAqPCR(TM) TB/NTM detection kit; PANAGENE, Korea) assay has been recently developed for the simultaneous detection of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) in clinical specimens. The study was aimed at evaluation of the performance of PNA probe-based real-time PCR in respiratory specimens. METHODS: To evaluate potential cross-reactivity, the extracted DNA specimens from Mycobacterium species and non-mycobacterial species were tested using PNA probe-based real-time PCR assay. A total of 531 respiratory specimens (482 sputum specimens and 49 bronchoalveolar washing fluid specimens) were collected from 230 patients in July and August, 2011. All specimens were analyzed for the detection of mycobacteria by direct smear examination, mycobacterial culture, and PNA probe-based real-time PCR assay. RESULTS: In cross-reactivity tests, no false-positive or false-negative results were evident. When the culture method was used as the gold standard test for comparison, PNA probe-based real-time PCR assay for detection of MTBC had a sensitivity and specificity of 96.7% (58/60) and 99.6% (469/471), respectively. Assuming the combination of culture and clinical diagnosis as the standard, the sensitivity and specificity of the new real-time PCR assay for detection of MTBC were 90.6% (58/64) and 99.6% (465/467), respectively. The new real-time PCR for the detection of NTM had a sensitivity and specificity of 69.0% (29/42) and 100% (489/489), respectively. CONCLUSIONS: The new real-time PCR assay may be useful for the detection of MTBC in respiratory specimens and for discrimination of NTM from MTBC.

Evaluation of a New Immunochromatographic Assay Kit for the Rapid Detection of Norovirus in Fecal Specimens

Rapid and accurate detection of norovirus is essential for the prevention and control of norovirus outbreaks. This study compared the effectiveness of a new immunochromatographic assay kit (SD BIOLINE Norovirus; Standard Diagnostics, Korea) and real-time reverse transcription-PCR (RT-PCR) for detecting norovirus in fecal specimens. Compared with real-time RT-PCR, the new assay had sensitivity, specificity, positive predictive value, and negative predictive value of 76.5% (52/68), 99.7% (342/343), 98.1% (52/53), and 95.5% (342/358), respectively. The sensitivity of the assay was 81.8% (18/22) for GII.3 and 75.7% (28/37) for GII.4. None of the 38 enteric virus-positive specimens (3 for astrovirus, 5 for enteric adenovirus, and 30 for rotavirus) tested positive in the cross-reactivity test performed by using this assay. The new immunochromatographic assay may be a useful screening tool for the rapid detection of norovirus in sporadic and outbreak cases; however, negative results may require confirmatory assays of greater sensitivity.

Enterovirus infection in Korean children and anti-enteroviral potential candidate agents / 소아과

Although most enterovirus infections are not serious enough to be life threatening, several enteroviruses such as enterovirus 71 are responsible for severe, potentially life-threatening disease. The epidemic patterns of enteroviruses occur regularly during the year, but they may change due to environmental shifts induced by climate change due to global warming. Therefore, enterovirus epidemiological studies should be performed continuously as a basis for anti-viral studies. A great number of synthesized antiviral compounds that work against enteroviruses have been developed but only a few have demonstrated effectiveness in vivo. No proven effective antiviral agents are available for enterovirus disease therapy. The development of a new antiviral drug is a difficult task due to poor selective toxicity and cost. To overcome these limitations, one approach is to accelerate the availability of other existing antiviral drugs approved for antiviral effect against enteroviruses, and the other way is to screen traditional medicinal plants.

Comparison of Clinical Features of Norovirus and Rotavirus Gastroenteritis in Hospitalized Children and Norovirus Genotype Analysis / 감염과화학요법

BACKGROUND: Norovirus is one of the most prevalent pathogens causing acute gastroenteritis in children. We compared the clinical features of noroviral gastroenteritis to those of rotaviral gastroenteritis and analyzed the noroviruses' genotype frequencies. MATERIALS AND METHODS: Stool samples were obtained form 433 children hospitalized with acute gastroenteritis from May 2008 through February 2009 at Soonchunhyang University Cheonan Hospital and examined for the presence of norovirus or rotavirus. We then analyzed the clinical features of noroviral gastroenteritis in comparison with rotaviral gastroenteritis and observed the capsid protein gene sequences from the isolated norovirus for genotyping. RESULTS: Norovirus was isolated from 69 patients (16.4%) and rotavirus from 49 patients (11.6%). The noroviral gastroenteritis patients experienced vomiting (77.4%), diarrhea (73.2%), and respiratory symptoms (53.6%); the rotaviral gastroenteritis patients experienced diarrhea (71.4%), dehydration (69.3%), and vomiting (65.3%). Dehydration in patients with noroviral gastroenteritis (43.4%) was rare compared with rotavirus (69.3%) (P=0.008). The isolated norovirus belonged primarily to the GII.4 genogroup (85.5%). Our phylogenetic analysis of the GII.4 isolates revealed 3 clusters, including novel cluster C. CONCLUSIONS: Vomiting was the most common symptom in noroviral gastroenteritis patients. Dehydration in noroviral gastroenteritis patients was less common compared with rotavirus gastroenteritis patients. The majority of the norovirus strains isolated from children with acute gastroenteritis belonged to the GII.4 genogroup.

Clinical significance of codetection of the causative agents for acute respiratory tract infection in hospitalized children / 소아과

PURPOSE: To determine the prevalence and clinical features of codetected respiratory etiological agents for acute respiratory infection in hospitalized children. METHODS: Nasopharyngeal aspirates were obtained from hospitalized children with acute respiratory infection at Dankook University Hospital from September 2003 through June 2005. Immunofluorescent staining and culture were used for the detection of respiratory viruses (influenza virus [IFV] types A, B; parainfluenza virus [PIV] types 1, 2, 3; respiratory syncytial virus [RSV]; adenovirus [AdV]). Polymerase chain reaction (PCR) assays were used for Mycoplasma pneumoniae (MP) and Chlamydia trachomatis (CT) detection, and PCR and culture were performed for enterovirus detection. Acid-fast staining and culture were performed for tuberculosis detection. The demographic and clinical characteristics were reviewed retrospectively from the patients medical records. RESULTS: Evidence of two or more microbes was found in 28 children: RSV was detected in 14, PIV 3 in 10, AdV in 10, MP in 8, PIV 2 in 8, CT in 4, and PIV 1 in 3. Codetected agents were found as follows: RSV+PIV 2, 6 patients; AdV+MP, 4 patients; AdV+PIV, 3 patients; RSV+MP, 3 patients; PIV 1+PIV 3, 3 patients. Distinct peaks of codetected agents were found in epidemics of MP and each respiratory virus. CONCLUSION: The codetected infectious agents were RSV, PIV, AdV, and MP, with distinct peaks found in epidemics of MP and each respiratory virus. Although advances in diagnostic methods have increased the prevalence of codetection, its clinical significance should be interpreted cautiously.

Isolation of Enterovirus Type 71 in a 3-year-old Boy Suffering from Toxic Epidermal Necrolysis / 소아알레르기및호흡기학회지

Toxic epidermal necrolysis (TEN) is an exfoliative disease of skin and characterized by flaccid bullae and spreading erythema so that the skin has the appearance of being scalded. It results primarily from a toxic reaction to various drugs, but occasionally occurs as a result of infection, neoplastic conditions, or other exposure. Enterovirus 71 (EV 71), the most recently described serotype of the genus Enterovirus (family Picornaviridae), causes a variety of diseases, including aseptic meningitis, encephalitis, poliomyelitis-like paralysis, hand-foot-mouth disease, gastroenteritis, fever and rash. A 3-year-old boy presented at the Department of Pediatrics, Soonchunhyang University Cheonan Hospital due to TEN. There were no definite causes such as drug toxicity, Graft-Versus-Host disease (GVHD) and infection. However, we could have isolated EV 71 from the patient's stool. Until now, there have been no reports showing the relationship between EV 71 and TEN, we report here in a case of TEN-associated with EV 71. Further evaluation is needed to study the relationship of TEN with EV 71.

Cause of enteroviral infection in children in chungnam area summer, 2005 / 소아과

PURPOSE: Enterovirus infection is a type of viral infection that occurs relatively frequently in children during summer. It has clinical symptoms of non-specific fever, aseptic encephalomeningitis, gastrointestinal diseases, skin rash and, hand-foot-mouth disease. However, it can also occcaisionally, result in fatal symptoms like myocarditis, epicardial inflammation, transverse myelitis, quadriplegia and etc. There have been epidemic enterovirus studies, but not in the Chungnam area. Therefore, we undertook this study in order to comprehend the cause viruses in this area. Methods: We enlisted 157 children hospitalized with enteroviral infections at Soonchunhyang University hospital in Cheonan between May and August 2005. Cerebrospinal fluids or feces were collected during the acute phase after hospitalization, and observed the cytopathic effects caused by enterovirus and using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The number of children hospitalized due to possible enteroviral infection during the period of study was 157. The number of children who tested positive with the reverse transcription polymerase chain reaction totalled 32 cases (20.4 percent). Among the children with entroviral diseases, 20 were male and 12 were female, thus the sex ratio of male to female was 1.67:1. Their clinical symptoms included fever most frequently (93.7 percent), was followed by headaches (90.0 percent), meningeal irritation signs (65.0 percent), and abdominal pain (30.0 percent). As for the type of isolated enterovirus, there were 17 cases of echovirus 18 and 6 cases of coxsackievirus B5. Furthermore, there were 2 cases of echovirus 9, 1 case of coxsackievirus A6 and coxsackievirus B3, respectively. But 5 cases were not determined by genotype. CONCLUSION: Echovirus 18 is circulating in Korea. We reported on identified enteroviruses, including echovirus 18, using RT-PCR in the Chungnam area during the summer of 2005.