Dongeun Yong
Ann Clin Microbiol 2009 September, 12(3): 103-109. Published on 20 September 2009.
Among gram-negative bacteria, rate of antibiotic resistance has been increasing. As a result, carbapenem is now considered as a last resort of therapeutic regimens for gram-negative bacterial infections. The choice of antibiotics has been impeded by the spread of organisms producing metallo-β-lactamases (MBL), which can confer resistance to nearly all β-lactams. MBLs have extremely diverse structures and are carried by various organisms including human pathogens. This review will focus on the classification and current status of MBL reported in Korea.
[in Korean]
Kui Hyun Yoon, Ji Hyun Cho
Ann Clin Microbiol 2009 September, 12(3): 110-115. Published on 20 September 2009.
Background: Direct immunofluorescence assay (DFA) and shell vial culture (SVC) have been used to diagnose respiratory viral infections. Recently a multiplex reverse transcriptase PCR (mRT-PCR) for 12 respiratory viruses has been introduced. We evaluated the diagnostic usefulness of these methods.
Methods: Among 275 nasopharyngeal aspirates (NPAs) received from pediatric patients during the 3-month period from May through July, 2007, 122 samples were selected so as to include diverse viruses and varying numbers of DFA-positive cells for mRT-PCR. Also, the results of the 85 NPAs that had been analyzed by both DFA and SVC were reviewed retrospectively.
Results: Detection rates for the seven major respiratory viruses, respiratory syncytial virus (RSV), influenza virus A and B, parainfluenza virus 1, 2, and 3, and adenovirus by DFA vs mRT-PCR were 32.0% and 55.7%, and by DFA vs SVC were 32.9% and 40.0%. A number of adenovirus detected by DFA vs mRT-PCR were 12 and 22, and by DFA vs SVC were 6 and 18. A number of RSV detected were 3 and 6, and 13 and 8, respectively.
Conclusion: mRT-PCR detected the respiratory viruses at the highest rate, followed by SVC and DFA in a decreasing order. However, DFA and multiplex PCR were more sensitive than SVC for RSV, while SVC was more sensitive than the other methods for adenovirus.
[in Korean]
Tae Youn Choi, Young Ik Seo, Tae Hyong Kim, Jeong Won Shin, Rojin Park
Ann Clin Microbiol 2009 September, 12(3): 116-121. Published on 20 September 2009.
Background: For the diagnosis of HIV infection, enzyme immunoassay (EIA) or chemiluminescence immunoassay (CLIA) is commonly used as a screening test. Although these methods have a high sensitivity and low cost, their high false positive rate can cause confusion in the patients and clinicians until a more specific test is done. OraQuick Advance Rapid HIV-1/2 Antibody Test (OraQuick) (OraSure Technologies, USA) is a rapid test that can detect HIV-1/2 antibodies in 20 minutes. It uses oral fluid, whole blood or serum sample. In this study, we evaluated the usefulness of the OraQuick as a screening and point-of-care test for HIV infection.
Methods: From Jan 2007 to Dec 2008, 45,276 samples referred to our laboratory were tested by CLIA method using the ADVIA Centaur (Bayer Healthcare LTD., USA) for HIV-1/2 antibody detection. Among them, 74 positive and 50 negative samples were tested by the Western immunoblot assay (WIB) and OraQuick test as a case-control study. Also, oral fluids from 30 HIV patients and 48 healthy persons were tested by OraQuick test.
Results: The sensitivity and specificity of OraQuick test (using serum samples) were 100% and 98.8% (95% confidence interval 96.9∼100%), respectively. OraQuick tests (using oral fluid samples) were all positive for HIV patients but all negative for healthy persons.
Conclusion: This study suggests that OraQuick can be used successfully as a rapid test for the early detection of HIV-1/2 antibody in patients visiting emergency departments and for the prevention of HIV infection in the health care providers.
[in Korean]
Da-Woon Kim, Jong Hee Shin, Seung Jung Kee, Soo-Hyun Kim, Myung Geun Shin, Soon Pal Suh, Dong Wook Ryang
Ann Clin Microbiol 2009 September, 12(3): 122-128. Published on 20 September 2009.
Background: VITEK-2 yeast susceptibility test (AST- YS01; bioMerieux, Hazelwood, MO, USA) has recently been introduced as a fully automated commercial antifungal susceptibility test system that determines MIC (minimum inhibitory concentrations) endpoints spectrophotometrically, thereby eliminating subjective errors. We compared the VITEK-2 system with the CLSI (the Clinical and Laboratory Standards Institute) M27 method for susceptibility testing of Candida isolates from Korea.
Methods: A total of 175 Candida bloodstream isolates were collected from two hospitals during a 18-month period. We compared the MIC results for amphotericin B, fluconazole and voriconazole obtained with the VITEK-2 system to those obtained by the CLSI M27 broth microdilution method after 24-hr and 48-hr incubation.
Results: VITEK-2 system MIC endpoints for 175 isolates were determined after 11.75 to 35.50 hr of incubation (mean, 16.3±4.8 hr). The essential agreement (within 2 dilutions) between amphotericin B, fluconazole and voriconazole MICs obtained by the VITEK-2 system and CLSI method was 98.3%, 90.9% and 96.0%, respectively, at 24-hr incubation and 100%, 92.6% and 94.9%, at 48-hr incubation. The categorical discrepancy for fluconazole was 6.3% (major error, 2.9% and minor error, 3.4%) at 24-hr and 6.3% (major error, 2.3% and minor error, 4.0%) at 48-hr. The categorical discrepancy for voriconazole was 1.7% (major error, 1.1% and minor error, 0.6%) at both 24-hr and 48-hr. There were no very major errors for fluconazole and voriconazole.
Conclusion: The VITEK-2 antifungal susceptibility test system appears to be rapid and highly correlative with the CLSI method, sugesting that this system can be effective for antifungal susceptibility testing for Candida species in the clinical laboratory.
[in Korean]
Ohgun Kwon, Young Uh, Ih Ho Jang, Hyeun Gyeo Lee, Kap Jun Yoon, Hyo Youl Kim, Yong Pyo Han
Ann Clin Microbiol 2009 September, 12(3): 129-132. Published on 20 September 2009.
Parvimonas micra is a non-spore-forming anaerobic gram-positive coccus, widely distributed as normal flora in the skin, vagina and mucosa, and able to cause opportunistic infections, particularly endocarditis and brain abscess following dental manipulations. A 49-year-old woman was hospitalized due to fever and headache. She had been diagnosed with periodontitis at the beginning of fever. A brain abscess was noted in the right temporal lobe on the brain CT, and she was treated with ceftriaxone, isepamicin and metronidazole. In the next day, abscess was aspirated and drained by a surgical procedure. An organism was isolated from an anaerobic culture of the abscess aspirate, and was identified as P. micra by a commercial kit and 16S rRNA sequencing.
[in Korean]
Soon Deok Park, Young Uh, Hyeun Gyeo Lee, Ih Ho Jang, Kap Jun Yoon, Mee Kyung Namgoong
Ann Clin Microbiol 2009 September, 12(3): 133-137. Published on 20 September 2009.
Rothia dentocariosa, a pleomorphic gram-positive branching bacillus, is a common inhabitant of the nose and throat. It is a well-known causative agent of dental plaques and periodontal diseases. Although generally regarded as having a low virulence to humans, R. dentocariosa has been recognized as causative agents of infective endocarditis and bacteremia with increasing frequency. Consequently, it can be a very serious pathogen when isolated from usually sterile sites such as blood or cerebrospinal fluid. We report a case of Rothia dentocariosa bacteremia without endocarditis in a 17-month-old male patient with fever, vomiting and diarrhea.
[in Korean]
Do Hoon Kim, Jung Sook Ha, Nam Hee Ryoo, Dong Suk Jeon, Jae Ryong Kim, Young Rok Do, Ki Young Kwon
Ann Clin Microbiol 2009 September, 12(3): 138-140. Published on 20 September 2009.
We experienced a case in which yeasts in blood sample from a patient with cervical cancer with hepatic metastasis and multiple intraperitoneal cysts interfered with platelet morphology flag in automated blood analyzer. The peripheral blood smear was performed to confirm the flag and revealed intracellular and extracellular yeasts, which were subsequently identified as Candida parapsilosis by blood culture.
Sang Taek Heo, In-Gyu Bae, Jin Yong Park, Sun-Joo Kim
Ann Clin Microbiol 2009 September, 12(3): 141-143. Published on 20 September 2009.
We report a rare case of cryptococcalmyositis with dissemination to lung in a 66-year-old diabetic woman who had no apparent risk factors for cryptococcal disease. She visited the hospital with a continuous pain in the right thigh and fever despite of treatment with antibiotics. She developed a localized lung infiltration. Crytococcus neoformans was isolated from the abscess of the right thigh and confirmed by molecular identification with DNA sequence analysis. Biopsy of the involved lung showed numerous budding yeasts consistent with Cryptocococcus species. The patient was successfully treated with surgical drainage and systemic antifungal agents.
Dong-Jin Park, Wonkeun Song, Taek-Kyung Kim, Jae-Seok Kim, Han-Sung Kim, Kyu Man Lee
Ann Clin Microbiol 2009 September, 12(3): 144-145. Published on 20 September 2009.
We collected 76 clinical isolates of Acinetobacter baumannii (amikacin MIC by Vitek 2 AST-N055 card: ≤2μg/mL, 11 isolates; 4μg/mL, 19 isolates; 8μg/ mL, 17 isolates; 16μg/mL, 27 isolates; and ≥64μg/ mL, 2 isolates) from a university hospital and evaluated the Vitek 2 AST-N055 card vs the broth microdilution as a reference method for testing susceptibility to amikacin. Vitek 2 AST-N055 card yielded very major errors in 15 isolates (19.7%) and minor errors in 26 isolates (34.2%). Of the 15 isolates shown very major errors, 14 had Vitek 2 MICs ranging from 8 to 16μg/mL. The results of our study suggest strongly that it is unreliable to test the amikacin susceptibility by Vitek 2 AST-N055 card of A. baumannii with the Vitek 2 MICs ranging from 8 to 16μg/mL. In those cases, another susceptibility test, such as broth microdilution (BMD), should be performed to confirm the results.
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