Yeon-Joon Park
Ann Clin Microbiol 2009 June, 12(2): 57-61. Published on 20 June 2009.
Aminoglycosides are one of the clinically relevant antibiotics. They kill bacteria by binding to bacterial 30S subunit of ribosome. Resistance to aminoglycosides occurs by three different mechanisms: 1. Production of an enzyme that modifies aminoglycosides, 2. Impaired entry of aminoglycoside into the cell by altering the OMP permeability, decreasing inner membrane transport, or active efflux, 3. The receptor protein on the 30S ribosomal subunit may be deleted or altered as a result of a mutation. By far, enzymatic modification has been the most important mechanism. In this review, the mechanisms of action and resistance, and the prevalence of resistance due to acquisition of enzymes are briefly described.
Sung Ju Kim, Ohgun Kwon, Young Uh, Gyu Yul Hwang, Ih Ho Jang, Kap Jun Yoon, Hyo Youl Kim
Ann Clin Microbiol 2009 June, 12(2): 62-66. Published on 20 June 2009.
Background: Staphylococcus saprophyticus is the second most common cause of urinary tract infections (UTIs) in young women. As little is known about the incidence of UTIs caused by this organism in Korea, we examined its frequency and clinical characteristics.
Methods: We analyzed the frequency of S. saprophyticus among organisms isolated from urine specimens in Wonju Christian Hospital from July 1996 to June 2008 and reviewed clinical characteristics retrospectively.
Results: Of 24,277 strains isolated from urine specimens during the past 12 years, 21 (0.09%) were S. saprophyticus. Outpatients were more common in the S. saprophyticus group than in all patients group (12 of 21, 57% vs 5,098 of 24,277, 21%). The incidence of S. saprophyticus in women was the highest in the group of 15 to 34 years of age. Monthly distributions of isolates were almost constant in all patient groups, while 16 of 21 (76%) cases of the S. saprophyticus group occurred in summer and fall (June to November).
Conclusion: The fequencies of S. saprophyticus among organisms isolated from urine specimens in all patient groups and women were 0.09% and 0.17%, respectively, and are much lower than those in other countries. However, we need further studies to examine the prevalence of S. saprophyticus UTIs in other regions of this country.
[in Korean]
Hyeong-Kee Yun, Soo-Hyun Kim, Duck Cho, Seung-Jung Kee, Myung-Geun Shin, Jong-Hee Shin, Soon-Pal Suh, Dong-Wook Ryang
Ann Clin Microbiol 2009 June, 12(2): 67-71. Published on 20 June 2009.
Background: The universal sample processing (USP) method has recently been introduced as a simple technique that is applicable to smear microscopy, culture, and polymerase chain reaction (PCR) for the detection of Mycobaterium tuberculosis (MTB). The present study evaluated the utility of the USP method for detecting MTB by culture and PCR, and the results were compared with that of the N-acetyl L-cysteine (NALC)-NaOH (6%) method.
Methods: All sputum specimens were digested and decontaminated by both the USP and NALC-NaOH methods, and the processed samples were inoculated for MTB culture and PCR. Culture was performed (252 samples) by using the MGIT system (Becton Dickinson Microbiology Systems, Sparks, Md, USA), and PCR test was conducted (281 samples) by using Amplicor MTB kit (Roche Molecular Systems, Branchburg, N.J., USA).
Results: MTB culture positive rates by NALC-NaOH and USP methods were 13.5% (34/252) and 11.9% (30/252), respectively (P＞0.05). There were no significant differences between the two methods for detecting MTB by PCR: the MTB PCR sensitivities by USP and NALC-NaOH methods were 77.8% (49/63) and 82.5% (52/63), respectively, and the specificities were 95.9% (209/218) and 96.3% (210/218), respectively (P＞0.05).
Conclusion: There were no significant differences between USP and NALC-NaOH methods of sample processing in enhancing the detection of MTB by culture or PCR.
[in Korean]
Young-Sook Cho, Young-Hoon Kim, Kyung-Hee Lee, Hye-Sun Jang, Kyung-Ah Hwang, Yoo-Li Kim, Hyun-Young Chi
Ann Clin Microbiol 2009 June, 12(2): 72-77. Published on 20 June 2009.
Background: Hepatitis C virus (HCV) RNA quantification is necessary for predicting the therapeutic response and assessing treatment results in patients with chronic HCV infection. Recently, real-time PCR technology for HCV RNA quantification displayed good linearity within the dynamic range. Thus, it is gradually replacing branched-DNA (bDNA) and PCR- hybridization assays. In this study, we evaluated the performance of the Real-QTM HCV quantification kit (biosewoom. Inc., Seoul, Korea) developed in Korea.
Methods: We evaluated the HCV quantification kit for detection limit, specificity, linearity, accuracy, and recovery rate of HCV RNA standard material. The results were analyzed for a correlation with those of Cobas Amplicor HCV Monitor 2.0.
Results: The HCV quantification kit showed a high recovery rate of HCV RNA standard material of various concentrations and amplication of HCV RNA equally in all genotypes. Hepatitis B virus and human immunodeficiency virus showed no cross-reactivity with HCV. Within-run and between-run coefficients of variation (CV) were 9.52∼15.84% and 9.40∼17.53%, respectively. Between-day coefficients of variation were 11.62∼18.04%, and detection limit was 44 IU/mL. It showed a good correlation with Cobas Amplicor HCV Monitor 2.0 (R2=0.8954).
Conclusion: The Real-Q HCV quantification kit showed a good specificity, sensitivity, linearity, and accuracy; therefore, we propose that it is fully adequate for monitoring antiviral therapy in patients with chronic HCV infection.
[in Korean]
Ji Hoon Huh, Sook Young Bae, Jang Su Kim, Kap No Lee, Chang Kyu Lee
Ann Clin Microbiol 2009 June, 12(2): 78-81. Published on 20 June 2009.
The HACEK group of bacteria (Haemophilus parainfluenzae, H. aphrophilus, H. paraphrophilus, Actinobacilus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corodens, and Kingella kingae) are the normal flora of the upper respiratory tract and oropharynx. The organisms infect abnormal cardiac valves, causing subacute native endocarditis or prosthetic valve endocarditis more than one year after valve surgery. Haemophilus species are responsible for only 0.5∼1% of all infective endocarditis cases. Embolization occurs in 60% and the mortality rate ranges from 16∼45% of cases of infective endocarditis caused by H. parainfluenzae. We experienced a case of infective endocarditis due to H. parainfluenzae in a 37-year-old male admitted with high fever, chills, nausea & vomiting, chest discomfort, and blurred vision. The organism was isolated from a blood culture and was identified as H. parainfluenzae by factor V requirement, negativity at urea, positivity at ornithine decarboxylase, and acid production from glucose and maltose. The patient was treated with antibiotics and symptoms and signs were improved.
[in Korean]
Ja Young Lee, Si Hyun Kim, Haeng Soon Jeong, Seung Hwan Oh, Hye Ran Kim, Young Il Yang, Yang Haeng Lee, Jeong Nyeo Lee, Jeong Hwan Shin
Ann Clin Microbiol 2009 June, 12(2): 82-86. Published on 20 June 2009.
Aggregatibacter aphrophilus is a facultatively anaerobic gram-negative coccobacillus or bacillus that grows with no dependence on X factor and variable requirement for V factor. The organism is normal flora in the human oral cavity and upper respiratory tract and, rarely, causes invasive infections such as bacteremia, endocarditis, brain abscess, or osteomyelitis. We report a case of septic peripheral embolism in left leg from A. aphrophilus endocarditis. A 49-year-old man with known hypertension presented with acute muscle pain in the left leg. On physical examination, a regular heartbeat with a pansystolic murmur was heard. There were decreased pulses in the left popliteal and dorsalis pedis arteries and coldness of the left foot, although sensory and motor functions were intact. Angiography revealed an embolus in a branch of the left femoral artery. He underwent emergency embolectomy, and gram-negative bacilli grew in the embolus cultures. The same microorganism was isolated in two pairs of blood culturs and subsequently identified as A. aphrophilus. Transthoracic echocardiography revealed mitral regurgitation and multiple vegetations on the mitral valve. The patient was treated with a third-generation cephalosporin for 4 weeks and mitral valve replacement in view of the diagnosis of infective endocarditis and septic peripheral embolism.
[in Korean]
Miyoung Kim, Mi-Hee Ahn, Ji Sang Kang, Hyun Lee, Sei-Ick Joo, Sung Sup Park, Eui-Chong Kim
Ann Clin Microbiol 2009 June, 12(2): 87-91. Published on 20 June 2009.
We report a case of pulmonary fungal ball of Pseudallescheria boydii (Scedosporium apiospermum, the anamorph) and the result of LSU rDNA D2 region sequencing of the clinical isolate. An immunocompetent 58-year-old female suffered 2-year history of hemoptysis. Her symptom persisted despite the administration of oral itraconazole, even though the clinical, radiological, and histological findings suggested Aspergilloma. In the fungal culture, the typical morphology of S. apiospermum was observed. Even though the sequencing using LSU rDNA D2 region identified the organism as Pseudallescheria ellipsoidea, one of the P. boydii complex, the further investigation of ours suggested that the species in P. boydii complex could not be differentiated from each other by the sequencing of LSU rDNA D2 region.
Kyeong Seob Shin, Dong Ik Shin, Woo Sub Shim, Byeong Cheol Rim, Il Hun Bae, Seung Young Lee, Dong Hee Ryu, Eun Jung Kim, Bo Ra Son
Ann Clin Microbiol 2009 June, 12(2): 92-96. Published on 20 June 2009.
Streptococcus salivarius meningitis is very uncommon, and most cases are iatrogenic, occurring after invasive procedures such as spinal anesthesia or lumbar puncture etc.. Post-traumatic occurrence of this infection is especially rare. A 20-year-old man with a previous history of skull base fracture was seen at the emergency department with signs of acute bacterial meningitis. The CSF had a few gram positive cocci with neutrophilic pleocytosis, which were identified as S. salivarius by the Vitek system (bioMerioux, Inc., Hazelwood, MO, USA), rapid ID 32 Strep (bioMerieux, Marcy-l’Etoile, France) and 16S rRNA sequencing. The microorganism showed intermediate resistance to penicillin (MIC=0.25μg/mL) but was susceptible to cefotaxime (MIC=0.25μg/mL) and vancomycin (MIC= 0.75μg/mL). The patient was treated with ceftriaxone and vancomycin. He also had his CSF leakage repaired by an endoscopic approach. To our knowledge, this is the first case of S. salivarius meningitis reported in Korea.
[in Korean]
Chang-Jin Moon, Jong-Hee Shin, Eun-Sun Jeong, Seung-Jung Kee, Soo-Hyun Kim, Myung-Geun Shin, Soon-Pal Suh, Dong-Wook Ryang
Ann Clin Microbiol 2009 June, 12(2): 97-101. Published on 20 June 2009.
We describe here a case of central venous catheter (CVC)-related bacteremia caused by Microbacterium species in a 14-year-old patient, who had received chemotherapy for acute lymphoblastic leukemia. All nine blood cultures obtained from admission day 2 to day 62 yielded the same yellow-pigmented coryneform rod. Both Vitek 2 (bioMerieux, USA) and MicroScan (Dade Behring, USA) identified the isolate as Micrococcus species, and the API Coryne (bioMerieux, France) identified the isolate as Rhodococcus or Brevibacterium species. However, the 16S rRNA gene sequence showed a 99% identity with Microbacterium species. The bacteremia was recurrent or persistent over 60 days despite alternate systemic antibiotic therapy, but blood culture became negative after an addition of teicoplanin lock therapy for eradicating CVC-related bacteremia. This represents the first report of CVC-related Microbacterium bacteremia cured by antibiotic lock therapy in Korea.
[in Korean]
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