Sun Hee Jun, Kee Hyung Sung, Sang Hoon Song, Kyoung Un Park, Hong Bin Kim, Junghan Song, Eun Hwa Choi, Sung Sup Park, Eui Chong Kim
Ann Clin Microbiol 2010 June, 13(2): 53-58. Published on 20 June 2010.
Background: Enteroviruses are the most frequent etiologic agents of aseptic meningitis and are estimated to be the cause of 70% to 90% of viral meningitis cases. Enterovirus diagnosis can be difficult because clinical features vary according to patient immunity and age. The purpose of this study was to evaluate the performance of the real-time nucleic acid sequence-based amplification (NASBA) assay compared to that of the real-time nested RT-PCR assay for enterovirus detection.
Methods: This study was performed on 96 patients suspected of aseptic meningitis based on clinical features. RNA was extracted using NucliSENS EasyMAG and real-time NASBA assay was performed using NucliSENS EasyQ Enterovirus and NucliSENS EasyQ Basic 2. We also executed in-house real-time nested RT-PCR assay for RNA extracted via QIAamp Viral RNA Mini.
Results: The positive rate of real-time NASBA assay was 45.8% for enterovirus detection. The positive rate of first real-time reverse transcription PCR was 22.9% and the second real-time PCR was 57.3%. The concordant rate of the real-time NASBA assay and first real-time reverse transcription PCR was 75.0%. The concordant rate of the real-time NASBA assay and second real-time PCR was 86.5%.
Conclusion: The detection of enteroviruses using the real-time NASBA assay is less prone to cross-contamination and is simple, without the need for reverse transcription. We conclude that the NASBA assay is an effective method for the rapid diagnosis of aseptic meningitis.
[in Korean]
Kyung Sun Park, Myeong Hee Kim, Tae Sung Park, Jin Tae Suh, Hee Joo Lee
Ann Clin Microbiol 2010 June, 13(2): 59-67. Published on 20 June 2010.
Background: In Korea, a sudden increase in vancomycin-resistant enterococci (VRE) infection has been noted since the late 1990s. This study was conducted to describe the antimicrobial resistances of enterococcal blood isolates and to identify risk factors associated with VRE bacteremia in a tertiary care university hospital over a recent five-year period.
Methods: This study was conducted to analyze the antimicrobial susceptibilities of enterococcal blood isolates by year from January 2003 to December 2007. Multivariate logistic regression analysis was used to investigate factors associated with VRE bacteremia.
Results: A total of 225 enterococcal strains (44.7% Enterococcus faecalis, 42.4% Enterococcus facium, 5.9% Enterococcus casseliflavus, and 4.7% Enterococcus gallinarum) were detected in blood, 55 of which (21.6%) were resistant to vancomycin. In 2004 and 2005, the resistance rates for vancomycin and teicoplanin (33.3% and 27.3%; 34.4% and 23.0%, respectively) increased. In 2003, 2006, and 2007, the resistance rates for vancomycin and teicoplanin (8.7% and 8.7%; 19.0% and 14.3%; 13.5% and 11.5%, respectively) decreased relative to those of the previous years. When 55 patients with VRE bacteremia were compared with 55 patients with vancomycin-susceptible enterococcal bacteremia using multivariate analysis, E. faecium bacteremia (OR 12.624, P＜0.001) and enterococcal bacteremia caused by species other than E. faecium and E. faecalis (OR 21.473, P=0.011) were found to be statistical risk factors. Among several infection control activities, the restricted uses of vancomycin and quinupristin-dalfopristin decreased the vancomycin resistance rate from 27.78% to 15.50% (P=0.0257).
Conclusion: VRE bacteremia would be effectively controlled via infection control activities based on studies regarding risk factors associated with VRE bacteremia.
[in Korean]
Kyung-Hee Kim, Jung-Eun Kim, Soon-Ho Park, Young-Hee Song, Jeong-Yeal Ahn, Pil-Whan Park, Yiel-Hea Seo
Ann Clin Microbiol 2010 June, 13(2): 68-72. Published on 20 June 2010.
Background: In January 2008, the Clinical and Laboratory Standards Institute (CLSI) published revised penicillin breakpoints for Streptococcus pneumoniae according to clinical presentation and the route of penicillin administration. The aim of this study was to evaluate the impacts of the new penicillin breakpoints on the susceptibility rates of S. pneumoniae isolated from blood.
Methods: A total of 156 non-duplicated S. pneumoniae strains recovered from blood of hospitalized patients were collected between January 2003 and December 2008. Penicillin and cefotaxime susceptibility tests were performed using an E-test (AB Biodisk, Solna, Sweden). Results of the penicillin susceptibility tests were analyzed using the former and new CLSI guidelines.
Results: Of the 156 S. pneumoniae strains isolated from blood, penicillin susceptibility under the former CLSI guidelines resulted in 42.3% susceptible, 42.3% intermediate, and 15.4% resistant states. According to the new CLSI guidelines (nonmeningitis, parenteral), 87.8% of isolates were susceptible, 9.6% were intermediate, and 2.6% were resistant to penicillin.
Conclusion: When the new CLSI guidelines are applied, the penicillin susceptibility rate of S. pneumoniae strains isolated from blood is considerably increased. This suggests that penicillin should still be useful for the treatment of nonmeningeal pneumococcal infections and that the use of broad-spectrum antimicrobials should not replace this treatment.
[in Korean]
Mi Hye Kim, Won Kil Lee
Ann Clin Microbiol 2010 June, 13(2): 73-78. Published on 20 June 2010.
Background: Chlamydophila pneumoniae is one of the major respiratory infectious pathogens and can be accurately diagnosed by cell culturing. The author performed this study to compare the usefulness of the collagen-coated polyethylene terephthalate (PET) disc culture method and that of the shell vial method.
Methods: Twenty-nine sputums and 17 blood specimens collected from 46 patients for C. pneumoniae culture were inoculated into HeLa-229 cell monolayers cultured in shell vials and polyester plates. After incubation, they were stained using the indirect immunofluorescent method with genus-specific FITC-conjugated anti-chlamydia antibody. When both results were inconsistent, microimmunofluorescence results were used.
Results: HeLa-229 cells successfully formed monolayers in shell vials and collagen-coated PET plates in all cases. Positive inclusion bodies in HeLa-229 cells of shell vials and PET plates for C. pneumoniae culture were similarly stained with the indirect immunofluorescent method. Both methods showed consistent results with 20 positive and 22 negative cases. The total agreement between the PET plate and shell vial was excellent (91.3%, k=0.826).
Conclusion: The collagen-coated PET disc culture method showed highly consistent results with that of the shell vial method, and no technical differences were experienced between the two methods. Therefore, the author concluded that the shell vial method could be replaced by the PET plate method for detection of C. pneumoniae.
[in Korean]
Tae-Hyoung Kim, Yong Seong Lee, Mi-Kyung Lee, Kyu Man Lee
Ann Clin Microbiol 2010 June, 13(2): 79-84. Published on 20 June 2010.
Background: Candida species are the fourth leading cause of nosocomial bloodstream infections and have one of the highest mortality rates among nosocomial pathogens. C. tropicalis has been reported to be one of the leading Candida species other than C. albicans to cause Candida infection in patients who have malignancy, diabetes mellitus, and burn. This study was designed to determine whether burn might influence the species distribution and susceptibilities of azoles against clinical isolates of Candida species including C. tropicalis.
Methods: A total 372 Candida isolates from various samples in a tertiary burn center were studied, and the MICs of Candida isolates to fluconazole, itraconazole, and voriconazole were tested by broth microdilution method of the Clinical and Laboratory Standards Institute (CLSI) M27-A2. A comparison was made between Candida isolates from burn patients and non-burn patients.
Results: The percentages of C. albicans, C. tropicalis, C. parapsilosis and C. glabrata isolates from burn patients and non-burn patients were 42.3% and 64.2% (P=0.000), 35.7% and 21.6% (P=0.002), 11.9% and 7.8%, and 10.1% and 6.4%, respectively. Decreased susceptibilities to fluconazole, itraconazole, and voriconazole were observed more frequently in burn patients (4.76%, 19.05%, and 0.60%, respectively) than non-burn patients (2.45%, 14.22%, and 0%, respectively).
Conclusion: The results of this study suggest that burn may lead to influence the species distribution and susceptibilities to azoles of Candida species.
[in Korean]
Hae-Sun Cho, Min-Chul Cho, Shinae Noh, Mi-Na Kim, Kyoung-Mo Kim
Ann Clin Microbiol 2010 June, 13(2): 85-89. Published on 20 June 2010.
Enterohemorrhagic Escherichia coli (EHEC) is an important cause of bloody diarrhea in children, but is considered to be rare in infants. Herein, a case of infant hemorrhagic colitis of verotoxin-producing E. coli O157:H7 diagnosed by multiplex PCR is reported. A nine-month-old boy was admitted to our hospital with bloody diarrhea for the previous two days. Multiplex PCR using SeeplexⓇ Diarrhea ACE Detection Kit (Seegene, Seoul, Korea) was directly applied to the stool specimens. Amplified bands specific for verotoxin, O157, and H7 indicated the presence of O157:H7 EHEC. The stool specimens were inoculated on sorbitol-MacConkey agar (SMA) and tryptic soy broth containing mitomycin C (TSB-M). Colorless colonies on sorbitol-MacConkey agar were O157-positive. TSB-M enrichment cultures of the stool specimen and the isolates were positive for verotoxin according to an enzyme immunoassay (EIA). The prepared ingredients of baby foods for the patient including ground meat, chopped carrot, chopped cabbage, and white rice porridge showed no EHEC on TSB-M and SMA. The patient’s parents and three-year-old sister did not recently have any gastrointestinal symptoms. Cefdinir was administered for one day and was ceased after diagnosis of EHEC colitis. The stool culture and verotoxin assay were negative on the second day of hospitalization. Application of multiplex PCR and verotoxin EIA directly to diarrheal stool warrants the rapid diagnosis and appropriate treatment of EHEC colitis.
[in Korean]
Hee Jae Huh, Seung Tae Lee, Jang Ho Lee, Chang Seok Ki, Nam Yong Lee
Ann Clin Microbiol 2010 June, 13(2): 90-92. Published on 20 June 2010.
Clostridium symbiosum was isolated from the blood of a 61-year-old immunocompromised woman who had diagnosed ovarian cancer with multiple metastases and who had developed persistent tachycardia. A blood culture was drawn from the peripherally inserted central catheter, and non-spore-forming gram-negative rods were detected in an anaerobic vial. The organism showed tiny and pinpoint colonies and was unidentified by Vitek II (bioMerieux, France). The 16S rRNA gene sequence showed a 99.4% identity with C. symbiosum. To our knowledge, this represents the first report of C. symbiosum isolation in Korea.
[in Korean]
Ah Ra Cho, Hye Ryoun Kim, Mi-Kyung Lee, Seong Ho Choi, Sin Weon Yun
Ann Clin Microbiol 2010 June, 13(2): 93-97. Published on 20 June 2010.
We report a case of catheter-related bacteremia due to Tsukamurella pulmonis. T. pulmonis is a rare cause of opportunistic infection in immunosuppressed patients and in cases of indwelling foreign materials. This infection was nearly impossible to identify using conventional phenotyping methods because of its similarities to the related genera Nocardia, Rhodococcus, Gordonia, Streptomyces, Corynebacterium, and Mycobacterium. This organism was initially misidentified as Mycobacterium aubagnense through PCR-RFLP analysis. We correctly identified this organism using 16S rRNA sequencing combined with phenotyping tests.
Hae-Sun Chung, Jang Ho Lee, Hyo Yeol Kim, Nam Yong Lee
Ann Clin Microbiol 2010 June, 13(2): 98-101. Published on 20 June 2010.
Allergic fungal sinusitis (AFS) is a noninvasive form of fungal rhinosinusitis resulting from an IgE-mediated hypersensitivity reaction. The diagnosis of AFS can be established by demonstrating type I hypersensitivity, presence of fungus in mucus, eosinophilic mucin, nasal polyposis, and characteristic CT scans. Although AFS is not unusual and its incidence may be increasing, few cases have been reported in Korea. Here, we report the first case of typical AFS in which Curvularia species was isolated by culture.
[in Korean]
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