Won-Kil Lee
Ann Clin Microbiol 2004 March, 7(1): 1-8. Published on 20 March 2004.
TTV는 1997년 일본의 Nishizawa 등이 최초로 발견한, 약 3.8 kb의 공유결합으로 폐쇄된 단일가닥의 DNA를 가진 무외피 바이러스로서 수혈과 관련된 원인불명(non-A to G)의 급, 만성 간염의 새로운 원인일 가능성이 있다고 제안되었다. 유전적으로는 무척 다양하여 16개의 유전형 외에 아형이 있으며, 현재 사용되고 있는 PCR 방법으로는 모든 유전자형을 검출하지 못하는 제한점이 있다. 최초 발표 이후 간질환과 관련성이 있다는 보고도 있지만, 건강한 사람에 있어서 높은 비율의 바이러스 혈증을 나타낸다는 보고로, 오히려 간병 변을 일으킨다는 것을 매우 의심할 수 있는 연구 결과가 많이 나오게 되어 “고아 바이러스”라고 간주하게 되었다. 그러나 앞으로 TTV와 질병과의 정확한 관계를 밝히기 위한 연구 과제로는, 모든 유전자형의 TTV를 검출할 수 있는 새로운 분자생물학적인 방법과 최근 감염과 과거 감염을 구분할 수 있는 새로운 혈청학적 검사법의 개발, 급성 병변에 초점을 맞추며, 만성 보균자의 오랜 기간 동안의 영향에 대한 연구 등이라고 사료된다.
[in Korean]
Sook-Jin Jang
Ann Clin Microbiol 2004 March, 7(1): 9-19. Published on 20 March 2004.
병원 감염의 역학적 연구에 있어서 기본적인 전제는 역학적 근건에서 얻은 분리주는 클론으로 연관되어 있어 공통된 특징들을 가지는 반면 역학적으로 무관한 분리주는 동일 균종이라 하더라도 여러 가지 특징이 다르다는 것이다. 이러한 전제에 의거하여 형별 검사를 하여 양자를 구별하려는 연구들이 역학적 분석을 위해 지속적으로 수행되어져 왔다. 형별 검사는 미생물에 의해 표현되는 특징들을 검사하는 표현형적 기법과 핵산체를 검사하여 의의 유전적 요소들을 DNA에 근거한 방법으로 직접 검사하는 유전형적 기법으로 분류된다[1]. 역학적 목적으로 사용될 최소의 형별 검사는 표현형적 기법이었지만 표현형적 특징이 주관적인 기법들은 같은 균종이나 아종(subspecies)의 분리주들간의 유전적 관계를 측정하는데 필요한 분석능을 제공해 주는 경우가 드물다. 이러한 분석은 여러 아형이 제기되는 역학적 의문을 해결하는데 필수적이다. 병원 감염의 근인자와 각 개인들과의 질환 분포, 새로운 고도 독성 또는 약제-내성 균주의 출현, 상재균 또는 감염 균주의 미세진화(microevolution), 병원균의 일반적인 집단 구조 등을 정확하게 동정하기 위해서는 형별 검사의 범위가 균종 동정으로부터 균주 및 아구주(substrain) 형별검사까지 확대되어야 한다. 아형 구분들에서 분리주들을 집단 분석을 통해 군분로 분별하기 위해 유전적 관련성을 정확히 측정할 필요가 있다. 그러한 정보를 제공할 수 있는 방법들이 개발되어 왔으며 연구자들은 관련성 여부를 규명하기 위해 그들이 선택한 방법이 적절한지를 확인해야 한다. 연구할 때 대답해야 할 질문을 분명하고 정확하게 서술하고, 도달해야 할 유전적 관련성의 수준을 결정한 다음, 그 질문에 답하는데 필요한 분석능을 가진 유전적 지문 식별법을 선택하고, 선택한 방법의 효율을 입증하는 것은 필수적이다.
[in Korean]
Jeong Man Kim, Hyun Kyung Kang, Seok Hoon Jeong, Il Kwon Bae, Su Bong Kwon, Byung Kyu Cho, Dool Man Kim, Hyun Joo Kim, and A Sung Kim
Ann Clin Microbiol 2004 March, 7(1): 20-26. Published on 20 March 2004.
Background : In recent years, Acinetobacter baumannii isolates acquired resistance to cefepime have increased significantly. The aim of this study was to survey the prevalence of PER-1 extendedspectrum β-lactamase (ESBL)-producing A. baumannii isolates in a University Hospital, Busan, Korea.
Methods :Antimicrobial susceptibilities were tested by the disk diffusion method, and double disk synergy test was performed for screening of ESBL-production. MICs were determined by agar dilution method. The isoelectric points of β-lactamases were determined by isoelectric focusing. Transferability of cefepime-resistance were tested by conjugation. blaPER-1 and blaPER-2 alleles were detected by PCR, and the DNA sequences of amplified products were determined by using the dideoxy-chain termination method.
Results :Among 51 clinical isolates of A. baumannii intermediate or resistant to cefepime, 10 isolates (19.6%) showed positive results in double disk synergy test. PCR-based experiments detected blaPER-1 gene in all the 10 isolates. All the isolates contained three β-lactamase bands: pI 5.3, 7.9, and 9.4. MICs of ampicillin, piperacillin, cephalothin, cefoxitin, cefoperazone, ceftazidime, cefotaxime, cefepime, and aztreonam were >256 mg/L, respectively, and them of imipenem were 8-16 mg/L.
Conclusion :The prevalence of PER-1-producing strains in Busan was less than that of in Seoul. But an outbreak of infection caused by this strain in an intensive care unit shows that spread of PER-1-producing A. baumannii strains can be anticipated in a near future. Prevention of hospital infection by these resistant microorganisms are needed.
[in Korean]
Nam Yong Lee, Eun Ha Koh, and Sunjoo Kim
Ann Clin Microbiol 2004 March, 7(1): 27-30. Published on 20 March 2004.
Background :Antibiotic resistance of group A streptococci (GAS) is increasing nationwide. Pulsed-field gel electrophoresis (PFGE) is useful for investigating genetic relationship among outbreaks of bacterial infection. Erythromycin (EM) resistance is mediated by either ermB, ermTR,or mefA gene. The emm gene encodes M protein which is the most important virulence factor of GAS.
Methods :The clonal relationship among 56 EM resistant GAS isolated from the children with acute pharyngitis in Jinju was investigated by analysis of chromosomal DNA restriction pattern with SmaI enzyme. The ermB and mefA genes were amplified and emm genotype was identified with PCR and sequencing. Their relationship with PFGE pattern was investigated.
Results :The emm genotyes were identified as 2, 3, 12, 18, and 75. Mostly emm 12 had ermB gene, while emm 3, 18 and 75 had mefA resistance gene. All strains with mefA gene were not restricted with SmaI. The emm12 strains showed 5 different PFGE patterns.
Conclusions :The emm genotypes were closely related with resistance genes. Analysis of macrorestriction fragment patterns by PFGE showed that EM resistant GAS were polyclonal at least in Jinju. GAS strains with mefAgene were not restricted with SmaI suggesting mefA gene might inhibit chromosomal digestion with SmaI.
[in Korean]
Hae-Sook Lee, Byung-Yeol Chun, Soo-Hee Jin, Won-Kil Lee
Ann Clin Microbiol 2004 March, 7(1): 31-37. Published on 20 March 2004.
Background : To compare the infection rate of Chlamydia pneumoniae in patients with respiratory symptoms and control group,
Methods : We recruited 189 patients (149 adults and 40 pediatric patients) with respiratory symptoms and 197 controls (159 healthy adults and 38 pediatric patients without respiratory symptoms) visited Kyungpook National University Hospital from August 2002 to July 2003. A serological test was done by micro- immunofluorescence (MIF) method. Antibody titers of IgG (1:32 or more) indicate past infection of C. pneumoniae. A recent infection was defined as one in which there is a high titer of IgG antibody (1:512 or more) or a positive IgM antibody (1:16 or more) with a negative for rheumatoid factor.
Results : The past infection rate of C. pneumoniae in case group (65.6%) was not significantly higher than 61.4% in control group. The past infection rate of C. pneumoniae of male patients (62.0%) was not significantly higher than 58.7% in control group, and in female showed the same pattern, 70.4% in patients and 63.8% in control group. The recent infection rate of C. pneumoniae in patients (13.2%) was not significantly higher than 9.6% in control group. The recent infection rate of C. pneumoniae of male patients (10.2%) was not significantly higher than 5.4% in control group, and in female showed the same pattern, 17.3% of patients and 13.3% of control group.
Conclusions : The recent infection rate of C. pneumoniae by IgG and IgM serological tests in patients with respiratory symptoms was not significantly higher than that in control group.
[in Korean]
Jeong Man Kim, Seok Hoon Jeong, Daeyoung Seo, Eun Hee Park, Eun Ju Song, Jae-Cheol Choi, Eun Yup Lee, and Chulhun L. Chang
Ann Clin Microbiol 2004 March, 7(1): 38-42. Published on 20 March 2004.
Background : It is important to define a source of infection when outbreak of Legionella infections has occurred. The performance of a molecular strain typing method was evaluated for environmental and clinical isolates of Legionella pneumophila.
Methods : Thirteen environmental strains, eleven clinical isolates and one type strain (ATCC 33152) of Legionella pneumophila were used for the analysis of pulsed field gel electrophoresis.
Results : All 25 strains were discriminated into 21 types. Two strains isolated from different locations in a same building showed different types. Each two, four, and two strains were shown as the same PFGE patterns.
Conclusions : Even though PFGE typing of Legionella pneumophila is excellent for strain differentiation, the same pattern does not necessarily indicate the same source of isolates.
[in Korean]
Young Uh, In Ho Jang, Kap Jun Yoon, and Hyo Youl Kim
Ann Clin Microbiol 2004 March, 7(1): 43-47. Published on 20 March 2004.
Background : Group B streptococci (GBS) is known to be major cause of neonatal meningitis and bacteremia, and the infections also has been increasing in adults, particularly those with serious underlying diseases. This study is designed to define the trend of infection rate by year, underlying conditions, clinical outcome of group B streptococcal bacteremia, and to compare the distribution of age, sex, and serotype and antimicrobial susceptibility between invasive and noninvasive GBS infections.
Methods : We analyzed the medical records of 36 cases with group B streptococcal bacteremia between 1990 and 2003, and compared the distribution of age, sex, serotype and antimicrobial susceptibility between invasive and noninvasive GBS infections with GBS strains stocked from 1990 to 2000 at Wonju Christian Hospital.
Results : Of 36 GBS bacteremia patients, four (11.1%) patients were early-onset neonatal infection, 9 (25.0%) were late-onset neonatal infection, and 23 (63.9%) were older than 30 years of age. In the 23 adult patients, 19 (82.6%) patients had one or more underlying diseases, and liver cirrhosis and diabetes mellitus were the most common underlying diseases. There is no significant difference of antimicrobial susceptibility and serotype distribution of GBS between invasive and noninvasive infections.
Conclusion :Bacteremia caused by GBS were prevalent in adult patients with chronic underlying diseases. In neonate, late-onset bacteremia was more common than early-onset bacteremia.
[in Korean]
Il Kwon Bae, Gun Jo Woo, Seok Hoon Jeong, Kwang Ok Park, Byung Kyu Cho, Dool Man Kim, Su Bong Kwon, Hyun Joo Kim, and Hyun Kyung Kang
Ann Clin Microbiol 2004 March, 7(1): 48-54. Published on 20 March 2004.
Background : The aim of this study was to survey the nation wide susceptibilities of Esherichia coli and Klebsiella pneumoniae against cefotaxime and to determine the prevalence of CTX-M-type extended-spectrum β-lactamases(ESBLs).
Methods : During the period of April to June, 2002, E. coli and K. pneumoniae isolates were collected from 13 hospitals. Antimicrobial susceptibilities to cefotaxime were tested by the disk diffusion method. ESBL production was determined by double disk synergy test. Cefotaxime-resistance of the ESBL-producers was transferred to azide-resistant E. coli J53 by conjugation. MICs of β-lactam antibiotics were determined by agar dilution method. Searches for blaCTX-M genes were performed by PCR amplication. pIs of β-lactamases were determined by isoelectric focusing.
Results : Ten percents of E. coli and 35 percents of K. pneumoniae isolates among 260 strains of each were intermediate or resistant to cefotaxime. Twenty-three isolates of E. coli and 78 K. pneumoniae isolates showed positive results in the double disk synergy test. One isolate of E. coli and 2 K. pneumoniae isolates harbored blaCTX-M-3 gene, 2 E. coli isolates harbored blaCTX-M-15 gene, and 2 E. coli and 2 K. pneumoniae isolates harbored blaCTX-M-14 gene.
Conclusion : E. coli and K. pneumoniae isolates producing CTX-M-type ESBLs are not uncommon in Korean hospitals. The spread of CTX-M-type ESBL genes could compromise the future usefulness of 3rd generation cephalosporins and aztreonam for the treatment of E. coli and K. pneumoniae infections.
[in Korean]
Jongyoun Yi, Jae-Kyoo Lee, Eun-Hee Chung, Dong Hee Cho, and Eui-Chong Kim
Ann Clin Microbiol 2004 March, 7(1): 55-58. Published on 20 March 2004.
Background : We investigated the causative agents of hemorrhagic diarrhea which occurred in newborn babies in a hospital nursery in July, 2002. Rotavirus was not confirmed as the cause because only a few patients were positive for rotavirus test while most others with hemorrhagic diarrhea were negative. Therefore, patients with bloody stool were tested for Salmonella, Shigella, rotavirus, adenovirus, enterovirus, astrovirus, and enterohemorrhagic Escherichia coli (EHEC).
Methods : Bloody stools from 12 newborns with hemorrhagic diarrhea were tested. Polymerase chain reaction (PCR) of shiga-toxin gene was performed for EHEC. Rotavirus and adenovirus were tested with latex agglutination kit (Orion Diagnostica). Reverse transcription (RT)-PCR was performed for enterovirus. To detect astrovirus, RNA was extracted with Viral RNA Mini Kit (QIAGEN), reverse-transcribed with random hexamer, and PCR-amplified with specific primers.
Results : Of the 12 patients tested, seven (58%) were positive for astrovirus RT-PCR while all were negative for Salmonella, Shigella, EHEC, rotavirus, adenovirus, and enterovirus.
Conclusions : Although diarrhea caused by astrovirus is known to be milder than that caused by rotavirus, our cases showed that astrovirus could cause serious bloody diarrhea in newborn babies.
[in Korean]
In-Suk Kim, M.D., Chang-Seok Ki, M.D., Eun-Hae Cho, M.D., Kwang Woong Lee, M.D., Sung-Ju Kim, M.D., Jae-Won Joh, M.D., Beom Kim, M.D., Woo seong Huh, M.D., Ha Young Oh, M.D., Nam-Yong Lee, M.D., Sun Hee Kim, M.D., and Jong-Won Kim, M.D.
Ann Clin Microbiol 2004 March, 7(1): 59-65. Published on 20 March 2004.
Background : Human parvovirus B19 infection has been known to cause chronic anemia, pure red cell aplasia, glomerulopathy and allograft dysfunction in kidney transplant (KT) recipients. The aim of this study was to evaluate the prevalence and clinical significance of B19 infection in KT recipients.
Methods : Five hundred and thirty seven serum samples from 167 KT recipients were included in the present study. The prevalence of B19 infection was based on either qualitative or quantatitive polymerase chain reaciton (PCR) with LightCycler Parvovirus B19 Quantification kit (Roche Diganostics, Mannheim, Germany). Clinical significance of B19 infection was investigated by retrospective review of hemoglobin levels and the results of kidney and bone marrow biopsies.
Results : Overall PCR positive rate was 18.3% (98/537) and 52 out of 167 (31.1%) KT recipients showed at least one positive PCR result. In addition, 20 out of 167 subjects (12.0%) showed PCRpositivity more than two consecutive times and they had significantly lower hemoglobin level than those with negative PCR result or only one-positive result (P< 0.0001 by ANOVA and multiple comparison). In addition, two patients (1.2%) suffered from pure red cell aplasia which was confirmed by bone marrow biopsy. Nevertheless, B19 infection did not seem to affect the graft outcome.
Conclusions : The parvovirus B19 infection in KT recipeints was not uncommon and was associated with low hemoglobin level and pure red cell aplasia after KT. Therefore, routine examination for the B19 infection should be provided for the KT recipients. To the best of our knowledge, this is the first report of the incidence and clinical significance of B19 infection in Korean KT recipients.
[in Korean]
Hyun-Ouk Song, Myoung-Hee Ahn, Han-Kyu Choi, Jae-Sook Ryu, Duk-Young Min, and Han-Il Ree
Ann Clin Microbiol 2004 March, 7(1): 66-71. Published on 20 March 2004.
Background : We analysed 205 cases of parasitic infection that were confirmed at Dept. of Parasitology, Hanyang University, College of Medicine from January 1986 to December 2003.
Methods : Parasitic worms were observed on gross examination or light microscope after treatment with lactophenol. Stool was examined with formalin-ether method for detection of eggs or protozoal cysts and scotch tape method was used for E. vermicularis eggs. In case of S. stercoralis, stool sample was incubated at 26℃ for 48 to 72 h to confirm filariform larvae. Commercial ELISA kit for T. canis and ELISA test with hydatid cystic fluid from a patient were evaluated. Tissues were stained H&E after 10% formalin fixation and observed under the light microscope.
Results : There were detected 31 species of parasite among 205 specimens. Nematodes of 84 cases (41.5%), Anisakis sp., P. decipiens, E. vermicularis and T. callipaeda, visceral larva migrans, T. trichiura, A. lumbricoides, S. stercoralis, cutaneous larva migrans, Mammomonogamus sp. were observed. Cestodes of 41 cases (21.0%), D. latum, sparganum, T. saginata, cysticercus cellulosae, hydatid cyst and trematodes of 34 cases (16.6%), C. sinensis, M. yokogawai, P. westermani and N. seoulense were noted. Protozoa of 34 cases (16.6%), E. histolytica, E. dispar, T. vaginalis, Plasmodium sp. G. lamblia, E. coli, E. nana, P. carinii and arthropoda of 11 cases (5.4%), I. nipponensis, P. pubis, T. floricolum and Culex sp. larva were classified.
Conclusions : Food-borne parasitic infections were distinctly noted in this analysis. And raw food or water are important as a source of parasitic infection in the future.
[in Korean]
Soyeon Seo, M.D., and Mi-Ae Lee, M.D.
Ann Clin Microbiol 2004 March, 7(1): 72-76. Published on 20 March 2004.
Background : Recently, non-typhoidal salmonellosis is increasing and it constituted over 90% of total salmonellosis in 1990s. The antimicrobial resistance of non-typhoidal Salmonella gets higher. So we described the change of serogroup and antimicrobial resistance of Salmonella isolated from clinical specimens in Ewha Womans University Mokdong Hospital during 6 years.
Methods : Clinical specimens were submitted from 1997 to 2002. Stool cultures were inoculated onto MacConkey (MAC) agar and Salmonella-Shigella(SS) agar and into Selenite F (SF) enrichment broth. Identification of Salmonella were performed by Vitek GNI card (BioMerieux, Marcy-I’Eltoile, France) and serotyping were done. Antimicrobial resistance test were performed by Vitek GNS card (BioMerieux, Marcy-I’Eltoile, France).
Results : From 1997 to 2002, 594 strains of Salmonella were isolated. Non-typhoidal Salmonella and Salmonella typhi constituted 94.4% and 5.6%. Non-typhoidal Salmonella were mainly composed of group B (21.5%) and group D (48.0%), but in 2002, group C (12.4%) and group E (27.9%) were increased in number. The antimicrobial resistance rate of non-typhpoidal Salmonella were 28% to ampicillin, 4.1% to SXT, 0.2% to ciprofloxacin and 0.7% to ceftriaxone. The animicrobial resistance rate of group B and D Salmonella showed 37.5% and 32.6% to ampicillin, 7.8% and 4.2% to SXT, respectively.
Conclusions : Serogroup B and D Salmonella were most frequently isolated, but group C and E Salmonella have been increased in 2002. Antimicrobial resistance of group B and D Salmonella were higher than other serogroups and have been increased year by year.
[in Korean]
Kyung Suk Kim, Jung Oak Kang, Dong Soo Han, Song-ja Chin, and Tae Yeal Choi
Ann Clin Microbiol 2004 March, 7(1): 77-83. Published on 20 March 2004.
Background : For the treatment of peptic ulcer diseases infected with Helicobacter pylori (H. pylori), amoxicillin, clarithromycin, and metronidazole are most commonly used. Recently the resistant rates against these antibiotics have been increased and this has become one of the major causes of treatment failure. It was recently demonstrated that metronidazole resistance is associated with mutation in rdxA gene that encodes an oxygen-insensitive NADPH nitroreductase. The aim of this study was to investigate the mutations of the rdxA gene for the metronidazoleresistant H. pylori isolates from Guri City, Korea.
Methods : H. pylori strains were isolated from gastric biopsy specimens from patients diagnosed as having peptic ulcer or gastric carcinoma in Hanyang University Guri Hospital. Antimicrobial susceptibility testing was performed by the modified broth microdilution method. Resistance was defined as metronidazole minimum inhibitory concentration (MIC) being more than 16 ug/mL Three metronidazole-sensitive and 10 metronidazole-resistant strains were selected to detect mutations in the rdxA genes by direct sequencing of PCR products.
Results : Of the 266 clinical isolates of H. pylori that were isolated from 1996 through 2001, 90 isolates (33.8%) showed metronidazole resistance. The frequency of nucleotide substitutions of the rdxA gene of 10 metronidazole-resistant strains (25-33/strain) was not so different from that of the three metronidazole-sensitive strains (22-26/strain). Stop signals generated by nucleotide substitution, insertion, or deletion, were found in 5 metronidazole-resistant strains (50%), but not in 3 metronidazole-susceptible strains.
Conclusion : The present study confirms that the presence of mutations on the rdxA gene causing a premature stopping of the inferred RdxA protein is associated with metronidazole resistance. But other genes or mechanisms might be implicated in the generation of metronidazole resistance and further investigations are needed.
[in Korean]
Jeong Hyun Kim, Won Ho Choe, Jung Oak Kang, and Tae Yeal Choi
Ann Clin Microbiol 2004 March, 7(1): 84-89. Published on 20 March 2004.
Mycobacterium abscessus is one of the species of rapidly growing mycobacteria that is widely distributed in nature. Using PCR-RFLP method, we have isolated 5 cases of M. abscessus from the soft tissue, sputum and blood, and further investigated each patient’s clinical courses and the results of the treatment. Three of the five patients had soft tissue infections, while the other two had pulmonary infections. Among the patients with soft tissue infections, two had a past history of steroid injection and the other had a trauma history. The clinical courses of these patients deteriorated quickly and they did not respond to the common anti-microbial antibiotics treatment. One of the two pulmonary infection patients, who had a past history of pulmonary tuberculosis and diabetes mellitus, had a more severe clinical course and difficulty on treatment than the patient who did not have a significant past history. M. abscessus can cause disseminated infection in immunocompromised patients and it most likely becomes resistant to antituberculous drug, therefore it is utmost necessary to perform rapid species identification and antibiotics susceptibility test.
[in Korean]
Hee Won Moon and Mi-Ae Lee
Ann Clin Microbiol 2004 March, 7(1): 90-93. Published on 20 March 2004.
Staphylococcus lugdunensis is a member of the coagulase negative staphylococci (CoNS) which has been associated with serious infections in humans. Species identification of S. lugdunensis isolates should be done but they may be misidentified as other CoNS species or Staphylococcus aureus due to positivity for clumping factor. We report the first two cases of catalase-positive and Gram positive cocci isolated from blood and venous catheter, which were positive for latex agglutination coagulase test but susceptible to penicillin, negative for tube coagulase test and negative acid production from mannitol and finally identified as S. lugdunensis.
[in Korean]
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