Kyungwon Lee, M.D. and Yunsop Chong, Ph.D.
Ann Clin Microbiol 2000 September, 3(2): 83-88. Published on 20 September 2000.
감염 질환을 흔히 일으키는 세균 중에 항균제 내성의 혼합을 이미 많이 알려져 있다. 특히 트랜스포존이 세 널리 사용되는 항균제에 대한 다제 내성 세균이 대단히 흔해졌다. Pseudomonas 감염 치료를 위해서는 유효한 항균제 선택에 어려움을 겪는 경우가 흔하다(1). 그람음성 간균 내성 유전자는 plasmid, 염색체 혹은 transposon에 들어있는 것이 발견되어, 이들 중에는 여러 가지 내성 유전자를 가지고 있어 다제 내성을 나타낸다. 내성 유전자가 integron이라고 하는 구조 중에 들어 있는 경우가 있다. 즉, 세균의 염색체나 plasmid 혹은 transposon이 있고, plasmid나 transposon 구조 중에는 integron이 있고, integron 중에는 cassette가 있으며, cassette 중에는 내성 유전자가 들어있는 경우가 있다(2).
Integron은 현재 4 종류가 알려져 있으며, 그 중 class 1, 2 및 3 integron은 항균제 내성 유전자를 가진 gene cassette도 있으며, 일부 내성 gene cassette는 integron 사이를 자유로이 이동할 수 있다(3). Class 4 integron은 Vibrio cholerae에서 보고되었다. Integron에는 공통적으로 integrase 유전자, integrase가 삽입되는 제조합부위 (attI site) 및 promoter가 있으며, 그 class는 integrase 유전자 (intl)의 염기서열에 의해서 구별된다(3).
[in Korean]
Sun-Moon Yang, M.D., Won-Kil Lee, M.D.
Ann Clin Microbiol 2000 September, 3(2): 89-93. Published on 20 September 2000.
프리온(prion)병은 1996년 영국에서 소의 광우병 (狂牛病)이라고 하는 소의 해면상 뇌증(bovine spongiform encephalopathy)과 크로이츠펠트-야콥병(Creutzfeldt-Jacob disease)의 변종 출현으로 뉴스에 보도되어 세인의 관심을 끄는 바 있었다(1).
프리온병이란 인간과 동물에 있어서 드물게 나타나는 치명적인 진행성 신경 변성 질환으로서, 지난 20년 동안 그 발생 기전은 정확히 밝혀내지 못한 밀명, 전염성 해면상 뇌증(transmissible spongiform encephalopathies, TSEs)을 지칭하며, 여기에 속한 병들은 거의 비슷한 임상 경과와 조직병리학적 소견을 나타낸다고 하였다. 이 질병은 모두 프리온(혹은 TSE 인자)에 의해 감염된다. 또한 Sigurdsson에 의하여 명명된 지연 감염(slow infection)은 숙령 내지 수년 내지 끄는 임상경과, 결국 모두 사망으로 이르고, 한가지 장기에서만 국한되어 있는 병소의 큰 범주 및 감수성 숙주의 범위가 제한되어 있다는 것이다(2).
[in Korean]
Eui Chong Kim, M.D., Dong Young Lee, M.D., Hae Shim Choi, M.S., Se Ik Joo, M.S., Jung Hee Lee, M.S., Sang Hyun Kim, M.D. and Sung Hwan Ban, M.D.
Ann Clin Microbiol 2000 September, 3(2): 94-98. Published on 20 September 2000.
Background: Shiga toxin-producing Escherichia coli (STEC) was found in several serotypes of E. coli including O157 serotype. Sorbitol-MacConkey agar may be useful for the detection of E. coli O157, but is not helpful for the detection of sorbitol-fermenting STEC other than O157. Moreover, some strains of E. coli O157 can ferment sorbitol. In this study, in situ hybridization using DNA probe of shiga toxin was used for the isolation of STEC from the PCR-positive stool and sequence analysis of a part of shiga toxin gene was performed.
Methods: The stool was incubated in LB broth overnight and DNA was extracted from the culture fluid. Multiplex PCR was performed with primers for stx1 and stx2 genes. Specimen showed PCR-positive was incubated on MacConkey agar and colonies were blotted with nitrocellulose membrane. Digoxigenin-labelled DNA probe for shiga toxin was made by PCR and the positive colonies were detected with anti-digoxigenin-alkaline phosphatase conjugate and nitroblue tetrazolium. Agglutination test with antisera was performed for the serotyping and VTEC-RPLA kit was used for the toxin production. Sequence analysis of PCR products was performed with automatic sequence analyser.
Results: An stx1-negative, but stx2-positive PCR was observed in a three-year-old girl, who visited Kumi Hospital on July 19, 1999 complaining of vomiting and diarrhea. The positive colonies were isolated by in situ hybridization using stx2-specific DNA probe. The titers of stx1 and stx2 by VTEC-RPLA test were negative and 1:64, respectively. Agglutination for the serotyping was not observed with all of the O antisera. 160-nucleotide sequence of stx2 of this isolate was identical with bacteriophage 933W (GenBank X07865), except for the change (T→C) of 95th nucleotide and amino acid sequence was identical each other.
Conclusions: For the sensitive detection of STEC from the stool of patients with diarrhea, multiplex PCR is recommended with stx1– and stx2-specific primers, and in situ hybridization should be performed on PCR-positive specimens for the isolation of STEC. This method may be helpful for the detection of STEC as the causative microorganisms in food-borne outbreak.
[in Korean]
Young Uh, Soon Deok Park, Jeong Seog Son, Hyeun Gyeo Lee, An Suk Jeoung, Hyun Mi Cho, and Kap Jun Yoon, and Hyo Youl Kim
Ann Clin Microbiol 2000 September, 3(2): 99-110. Published on 20 September 2000.
Background: In recent years, the incidence of extended-spectrum β-lactamase (ESBL) producing Klebsiella has been steadily increased, and the newer species K. planticola and K. terrigena, formerly regarded as nonpathogen, have been reported with astonishing frequency from human infectious processes by some investigators. The aim of this study is to elucidate the isolation rate and antimicrobial susceptibility of recent clinical Klebsiella isolates.
Method: For the clinical Klebsiella isolates during the period of June 1999 to May 2000, isolation frequency of Klebsiella species by specimen, departments, age, and sex were analyzed. And antimicrobial susceptibilities were also analyzed.
Result: Isolation rate of Klebsiella in order of decreasing frequency were K. pneumoniae (74.7%), K. oxytoca (12.1%), K. ozaenae (1.7%), K. planticola(1.0%), K. terrigena(0.9%), and K. ornithinolytica (0.7%), respectively. K. rhinoscleromatis was not isolated. Compared with outpatients, increase of resistance rates of inpatients’s Klebsiella isolates were 10% in ciprofloxacin, 15% in cefoperazone/sulbactam, and the others were ranged from 24% to 31%. Isolation rate of ESBL producing K. pneumoniae by double disk (DD) synergy test was 41%, and detection rates by antimicrobial agents were as follows: cefotaxime (95%), aztreonam (58%), and ceftriaxone (37%). Antimicrobial susceptibility rate with the exception of ampicillin and imipenem decreased from the range of 81%-96% on admission day to 29-62% after one week on admission.
Conclusion: The isolation rates of K. planticola and K. terrigena were less than 1%. The proportion of ESBL producing K. pneumoniae was 41%. And the vast majority of multidrug resistant Klebsiella including ESBL producing strains are acquired by hospitalization.
[in Korean]
Jongwook Lee, M.D., Nam Keum Lee, M.T., Soo Hwan Pai, M.D., Pum Soo Kim, M.D., Won Choi, M.D., Don Hang Lee, M.D., Hyung Gil, M.D., and Young Soo Kim, M.D.
Ann Clin Microbiol 2000 September, 3(2): 111-115. Published on 20 September 2000.
Background: Helicobacter pylori (H. pylori) is closely associated with gastritis, peptic ulcer and gastric carcinoma. We evaluated the reliability and usefulness of ¹³C-urea breath test (¹³C-UBT) for the detection of H. pylori infection and searched for the cut-off value of the test.
Method: We investigated 45 patients, who underwent esophagogastroduodenoscopy with multiple biopsy specimens taken for culture, histology and rapid urease test, and ¹³C-UBT. Sensitivity and specificity of UBT were calculated against the combined biopsy-based test results.
Result: Of 45 patients, 26 were found to be H. pylori-positive according to combined biopsy-based test results. Sensitivity and specificity of the ¹³C-UBT were 100.0% and 89.5%, respectively.
Conclusion: The urea breath test provides a simple and reliable and noninvasive method of assessing H. pylori infection status.
[in Korean]
Oh-Gun Kwon, M.D., Hyun Mi Cho, M.T., In Ho Jang, M.S., Young Uh, M.D., and Kap Jun Yoon, M.D.
Ann Clin Microbiol 2000 September, 3(2): 116-120. Published on 20 September 2000.
Background: As many as several weeks of incubation may be necessary for the recovery of mycobacteria when conventional culture media are used. Previous studies evaluating Mycobacteria Growth Indicator Tube (MGIT) as a rapid for the growth and detection of mycobacteria from clinical specimens have been reported. We compared MGIT with Ogawa media for the recovery of mycobacteria from clinical specimens.
Methods: Ninety nine clinical specimens received in the laboratory of Wonju Christian Hospital from June to September 1999 were used for this study. The specimens from nonsterile body sites were digested, decontaminated, and concentrated for culture and Ziehl-Neelsen stain, and specimen were inoculated onto MGIT tube and 3% Ogawa egg medium, and cultured for 8 weeks.
Results: Of the 38 specimens culture-positive for mycobacteria, 3 grew isolates in MGIT medium only, 8 grew isolates in Ogawa media only, and 27 grew isolates in both media. Mean (median, range) times to detection of mycobacteria were 13.7 (5.5, 2-48) days with MGIT and 19.6 (18, 13-37) days with Ogawa (P>0.05). The number recovered with MGIT plus Ogawa media was 24 (63.2%) within 14 days of receipt of specimen, and 31 (81.6%) within 21 days. The contamination rates were 31% for MGIT and 1% for Ogawa media.
Conclusions: MGIT appears useful to quickly detect and identify mycobacteria from clinical specimens. However, because the number of culture-positive specimen in MGIT was not greater than those recovered with Ogawa media, MGIT should be used in combination with solid media to reduce turnaround times and increase the isolation rate.
[in Korean]
Jung-Hee Lee, M.S., Byoung-Yoon Ahn, Ph.D., Sung-Hwan Ban, M.D., Sang-Hyun Kim, M.D., and Eui-Chong Kim, M.D.
Ann Clin Microbiol 2000 September, 3(2): 121-131. Published on 20 September 2000.
Background: The determination of serotype of enteroviruses is useful for the discrimination between sporadic and epidemic infections. The conventional serotyping method is time-consuming and labor-intensive. Recently, molecular method was introduced for the serotyping of enteroviruses. The aim of this study was to establish a method to isolate and analyze enteroviruses from various specimens utilizing molecular biological techniques and to determine which strains were phylogenetically related to clinical samples.
Methods: Clinical samples in this study included 164 cerebrospinal fluid (CSF), 136 stool, 15 sera, 6 throat swab, 5 urine, and 4 sputa, which were obtained from hospitalized patients, primarily infants or children presenting symptoms of aseptic meningitis in 1998. RD cells were used for enterovirus isolation. RT-PCR was performed with RD cell lysate showing CPE. The primers 011 and 012 were used for the VP1 region, and the primers EN1 and EN2 for 5’-UTR. The nucleotide sequences of VP1 region were determined and analyzed with BLAST program.
Results: Among 333 samples, only 23 samples produced CPE: 17 samples at first and six samples at the second blind passage. Fifteen isolates were related to coxsackievirus B2, two to echovirus 4, three to echovirus 6, and three to echovirus 18. All 23 viral isolates displayed a nucleotide sequence identity of 80-95%, compared with the reference serotypes. However, the identity was increased up to 93-100% when the VP1 region was translated into amino acids.
Conclusions: Since CB2 type was 55% among enteroviral isolates, the CB2 was determined as the major causative serotype of enteroviral meningitis in 1998. CB2 type was emerged between June and July, EC4 and EC6 was limited to July, and EC18 was in August.
[in Korean]
YS Kim, KK Lee, SY Park, HJ Lee, and JT Suh
Ann Clin Microbiol 2000 September, 3(2): 132-136. Published on 20 September 2000.
Background: Among many serologic and molecular methods, direct detection of HBV DNA in serum appears to be the most reliable method for monitoring HBV infection and assessing the response to anti-viral treatment. Generally, polymerase chain reaction (PCR) with high sensitivity and hybridization analysis with quantification are available for detecting the presence of HBV DNA in serum. In this study, we compared Digene Hybrid Capture™ HBV DNA assay with in-house PCR assay.
Methods: We performed in-house nested PCR in 44 patients with negative results and 16 patients with weakly positive results (≤17 pg/mL) by Digene Hybrid Capture™ HBV DNA assay.
Results: Of the 44 negative patients of Digene Hybrid Capture™ HBV DNA assay, 26 (59.1%) were positive and 18 (40.9%) were negative for PCR. Of the 16 Digene Hybrid Capture™ HBV DNA assay weak positive patients, all (100%) were positive for PCR.
Conclusions: Although the hybridization method is less sensitive than the PCR, it is considered to be a standard procedure and quantitative method. So, if combined with PCR, the hybridization method will be useful for monitoring HBV infection and assessing the response to anti-viral treatment.
[in Korean]
Hyukmin Lee, M.D., Kyungja Woo, M.T., Kyungwon Lee, M.D., Yunsop Chong, Ph.D., and Joo Hang Kim, M.D.
Ann Clin Microbiol 2000 September, 3(2): 137-141. Published on 20 September 2000.
Plesiomonas shigelloides was isolated from blood culture of a 53-year-old man with fever, who had treatment history of gastrointestinal malignancy. The patient showed neither clinical features nor hematological finding which suggest bacteremia. Identification of the isolate was delayed because of its similar characteristics with Aeromonas spp. and other gram-negative bacilli. The isolate was misinterpreted as susceptible to ampicillin by the first disk diffusion test. It may not always easy to identify P. shigelloides by conventional tests and to determine its antimicrobial susceptibility accurately, as laboratorians rarely have experience with the organism and as the organism may show unusual inhibition pattern when tested by disk diffusion method or Etest.
[in Korean]
Do Sim Park, M.D., Young Jin Lee, M.D., Shin Moo Kim, and Ji Hyun Cho, M.D.
Ann Clin Microbiol 2000 September, 3(2): 142-146. Published on 20 September 2000.
Vibrio cholerae strain other than O1 and O139 (Vibrio cholerae non-O1/O139) are associated with sporadic diarrhea and have often been reported in association with extraintestinal infections. We report a case of peritonitis by V. cholerae non-O1/O139 in 43-year-old male who was diagnosed cirrhosis. He was complained of abdominal distension and fever without history of consumption of raw sea food and exposure to sea water. Gram negative bacilli were cultured from his peritoneal fluid and identified as V. cholerae sero group O14.
[in Korean]
Ji Soo Kim, M.D., Soo Yeon Park, M.D., Yeoung Chul Kil, M.T., Hee Joo Lee, M.D., and Jin Tae Suh, M.D.
Ann Clin Microbiol 2000 September, 3(2): 147-150. Published on 20 September 2000.
V. parahaemolyticus or V. alginolyticus infections are usually associated with consumption of raw or undercooked shellfish, contaminated food, and exposure of wounds to warm seawater. V. parahaemolyticus causes gastroenteritis (the most common syndrome), wound infections, and septicemia. V. alginolyticus occasionally causes extraintestinal infections in humans. So far, the authors have not found the report of V. parahaemolyticus and V. alginolyticus isolation from a patient. So, we report a case of concurrent isolation of V. parahaemolyticus and V. alginolyticus from a patient who had a history of intestinal diarrhea and vomiting.
[in Korean]
For Authors
Publisher
Sponsors
