Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


Weeks in Review


Weeks to Publication
Indexed in KCI, KoreaMed, Synapse, DOAJ
Open Access, Peer Reviewed
pISSN 2288-0585 eISSN 2288-6850

March, 1999. Vol. 2 No. 1.

Review article

Vancomycin-resistant Staphylococcus aureus

Chik Hyun Pai, M.D. and Mi-Na Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 1-7. Published on 20 March 1999.

Clinical isolates of Staphylococcus aureus with reduced susceptibility to vancomycin (VRSA) have been reported from Japan, the United States, and France. Although the isolates are considered intermediately resistant according to the National Committee for Clinical Laboratory Standards (NCCLS), they are already a cause of serious concern in the ever-worsening antibiotic crisis of today, because they are all methicillin-resistant S. aureus (MRSA) and they are isolated after prolonged and unsuccessful vancomycin therapy. Furthermore, a study in Japan showed a high prevalence of “hetero-VRSA,” MRSA strains that are susceptible to vancomycin according to NCCLS, but contain subpopulation of VRSA at the frequency of ≥10⁻⁶ and thus can be converted easily to full-blown VRSA upon exposure to the antibiotic. Recent reports from Seoul showed that hetero-VRSA is also prevalent in Korea.

This review is to examine the epidemiology, clinical significance, mechanisms, and laboratory detection of vancomycin resistance in clinical isolates of S. aureus; and to summarize infection control guidelines recommended by Centers for Disease Control and Prevention and others for this newly emerging nosocomial pathogen. 

[in Korean]

Original article

Occurrence and Clinical Characteristics of Patients Infected with Subgroups of Respiratory Syncytial Virus

Wonkeun Song, M.D., Kyu Man Lee, M.D. and Hyun Tae Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 8-13. Published on 20 March 1999.

Background:Respiratory syncytial virus (RSV) is the single most common cause of lower respiratory tract infections in infants and young children. RSV can be classified into two major groups, A and B with subgroups based on their reactivity with monoclonal antibodies. There were no reports on the subgroups of RSV isolates in Korea. The purpose of this study is to identify RSV isolates from patients with lower respiratory tract infections to subgroup level and to examine clinical characteristics of subgroup infections.

Methods:RSV infection was diagnosed by viral culture of nasopharyngeal aspirates in patients with lower respiratory infection. Forty two RSV isolates over four successive outbreaks (94/95, November 1994-January 1995; 95/96, Nov. 95-Jan. 96; 96/97, Nov. 96-Jan. 97; 97/98, Nov. 97-Jan. 98) were subgrouped by indirect immunofluorescence with subgroup-specific monoclonal antibodies. Clinical characteristics of subgroup infections were evaluated by review of medical records.

Results:Twenty eight (67%) isolates were identified as group A and 14 (37%) strains as group B. Group A isolates of the 94/95, 95/96, and 96/97 seasons were subgroup A/4, and those of 97/98 season were subgroup A/2. Group B isolates were all identified as subgroup B/2. There was no statistically significant difference in clinical characteristics according to the subgroup infections.

Conclusions:This study show that RSV subgroup A/4, A/2 and B/2 isolated over recent four successive epidemic seasons in Seoul. There was no significant difference in clinical characteristics or severity according to the subgroup infections. 

[in Korean]

Original article

Serial Evaluation of Serotypes of Group A Streptococci Isolated from Throat Culture of Normal School Children

Yun Jeong Kim, M.D. and Seon Ju Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 14-18. Published on 20 March 1999.

Background:Group A streptococci (GAS) cause various infections in the school children. The change of isolation rate of GAS between time interval was observed by repeated throat cultures and acquisition rate of new strain was investigated by comparing the serotypes of GAS.

Methods:Throat cultures were taken from the school children in Chungnam and Seoul. Second throat cultures were taken from 119 children in Chungnam after 1 month and from 59 children in Seoul after 4 months, who showed GAS in the first throat culture. Serotypings such as T, M and opacity factor typing were performed and compared against 40 children in Chungnam and 26 children in Seoul who grew GAS in both throat cultures.

Results:GAS were isolated from 57.1% (68/119) in Chungnam and 45.8% (27/59) in Seoul in the second throat culture. Different serotypes between first and second throat culture were 5 of 40 (12.5%) in Chungnam and 4 of 26 (15.4%) in Seoul, respectively.

Conclusions:Almost half of children contained GAS continuously until 4 months and acquisition rate of new serotypes was 14.0% during this time. When GAS is repeatedly isolated, serotyping was very useful to recognize whether the strain is same or not.

[in Korean]

Original article

DNA Sequence Analysis of the V3 loop of HIV-1 from Korean Patients with AIDS

Jae Seok Kim, M.D., Sung Sup Park, M.D., Kyou Sup Han, M.D., Eui Chong Kim, M.D., Jin Q Kim, M.D., Myoung Hee Park, M.D. and Han Ik Cho, M.D.

Ann Clin Microbiol 1999 March, 2(1): 19-27. Published on 20 March 1999.

Background:Phylogenetic analysis was used to determine the subtype and the probable source of transmission of human immunodeficiency virus type 1 (HIV-1). The HIV-1 is an RNA virus characterized by extensive genetic variation. To determine the extent of HIV-1 genetic variation, HIV-1 envelope V3 domain structures were analyzed and compared. In this study, we analyzed phylogenetic relationships and the subtype of Korean isolates to help the epidemiological study of HIV-1 infection.

Methods:Peripheral blood mononuclear cells were collected from eight patients with AIDS. HIV-1 proviral DNA was directly amplified directly by polymerase chain reaction (PCR). V3 domain nucleotide sequences were determined using a direct sequencing method with PCR products. Phylogenetic analysis of V3 domain nucleotide sequences was performed comparing with previously documented HIV-1 strains.

Results:Six V3 loop sequences were obtained from eight HIV-1 infected patients. All of six HIV-1 strains were classified as subtype B by phylogenetic analysis of the V3 region. The distances between strains varied from 11.5% to 22.9% (mean; 15.9%), showing six strains were not related each other.

Conclusions:Six HIV-1 strains belong to subtype B, which is the prevalent type in North America, Europe, and Japan. Molecular epidemiological data supported the transmission of HIV-1 to Korea from these areas. Phylogenetic analysis revealed the absence of closely related strains in these isolates. Direct sequencing of V3 loop DNA would be a useful tool to determine the subgroup and the route of transmission of HIV-1. 

[in Korean]

Original article

Prevalence of Extended-spectrum β-lactamase-producing Enterobacteriaceae and Evaluation of Methods for Detection

Byung Lip Kim, M.D., Seok Hoon Jeong, M.D., Ja Young Koo, M.D., Kyungwon Lee, M.D., Yunsop Chong, Ph.D., Tae Jeon Jeong, M.T., Hyun Yong Hwang, M.D. and Mi Hyang Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 28-39. Published on 20 March 1999.

Background : Increased isolation of extended-spectrum β-lactamase ( ESBL)-producing Enterobacteriaceae resistant to third generation cephalosporins and aztreonam has been noted recently. This study was to determine the prevalence of resistance to these drugs and ESBL in Enterobacteriaceae and to evaluate the methods for detection.

Methods:During the period of October, 1997 and March, 1998, a total of 731 clinical isolates of Enterobacteriaceae were collected from patients of the Kosin Medical Center, Pusan, Korea. Antimicrobial susceptibility test by disk diffusion method and double disk synergy test were performed. MICs of β-lactams were determined by agar dilution method. And ESBL genotypes were determined by polymerase chain reaction.

Results:About 10% of Escherichia coli isolates and 20% of Klebsiella pneumoniae isolates were intermediate or resistant to the third generation cephalosporins or aztreonam. Sensitivities of cefotaxime, ceftazidime, ceftriaxone and cefpodoxime disks for the detection of ESBL- producing strains of E. coli and K. pneumoniae by NCCLS standards were 100%, respectively, but that of aztreonam disk was 97%. Positive predictive value of the ceftazidime disk was higher than those of other disks. Twenty strains of E. coli, 20 K. pneumoniae, 19 Enterobacter spp., six Citrobacter freundii, and eight Serratia marcescens showed positive results in double disk synergy test. The transconjugant strain of K. pneumoniae K20482 had blaSHV, and remains of transconjugants of ESBL-producing K. pneumoniaeEnterobacter spp. and S. marcescens had blaTEM.

Conclusions:In this study, many strains of Enterobacteriaceae isolated in Korea were resistant to third generation cephalosporins and aztreonam. Some of the strains of Enterobacter spp. and S. marcescens as well as E. coli and K. pneumoniae produced ESBL, and majority of these strains had blaTEM. In the detection of ESBL-producing strains of E. coli and K. pneumoniae by NCCLS standards, all of the antimicrobial agent disks tested were useful, but ceftazidime disk was most effective because of its highest positive predictive value.

[in Korean]

Original article

Molecular Epidemiological Typing of Clinical Strains of Methicillin-Resistant Staphylococcus aureus

Jung Man Kim, M.D., Kyeong Hee Kim, M.D., Tae Gyeom Kim, M.D., Young Gil Lee, Kyeong Heo, Yoo Jung Song and In Hoo Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 40-48. Published on 20 March 1999.

Background: Meicillin-resistant Staphylococcus aureus(MRSA) is a common cause of nosocomial infections worldwide. Identification of strains by molecular typing facilitates epidemiological studies and improves disease control. This study was performed to determine the usefulness of mecA-associated hypervariable region(HVR) polymerase chain reaction (PCR) and random amplified polymorphic DNA(RAPD) analysis in the investigation of a nosocomial MRSA infections.

Methods:Methicillin-resistance was identified by NCCLS disk diffusion method using the oxacillin disk. And PCR was done for detection of mecA gene. Antimicrobial susceptibility test, HVR-PCR and RAPD using 3 primers were performed for epidemiological analysis on isolates of MRSA.

Results:During the period from 1997 Dec. to 1998 May, 120 strains of S. aureus were isolated from clinical specimens. Among them, 78 strains were MRSA, and 72 strains were mecA positive. The strains of mecA positive MRSA were classified into four types by antibiogram, six genotypes by HVR-PCR, and 29 groups by RAPD using three primers. The combination of HVR genotypes and RAPD analysis showed 43 different types in 72 mecA positive MRSA isolates. The five strains which were repeatedly isolated from the same patients showed the same HVR genotypes and RAPD analysis.

Conclusions:Antibiogram, HVR-PCR, and RAPD could classify MRSA isolates into only 4-6 types, respectively, but combination of these methods could improve the typability. And combination of results of RAPD analysis using three primers were better than that using one primer in epidemiological studies of MRSA because of same reasons. It can be concluded that molecular typing of MRSA using HVR-PCR and RAPD assay is useful in epidemiolgical investigation of nosocomial infections caused by MRSA, because of its simplicity and reproducibility. 

[in Korean]

Original article

Evaluation of Frozen Antibiotics for Antimicrobial Susceptibility Testing of Helicobacter Pylori

Lae Hee Chun, M.D., Jung Oak Kang, M.D., Sun-E Kim, M.D. and Ile Kyu Park, M.D.

Ann Clin Microbiol 1999 March, 2(1): 49-53. Published on 20 March 1999.

Background:Antimicrobial susceptibility testing of Helicobacter pylori(H. pylori) is not yet standardized but broth dilution or agar dilution are considered as standard methods. In the broth microdilution method, antibiotic dilutions of different concentrations are made each time, but most of it is discarded because only small volumes of dilutions are used. To improve this tedious procedure and the waste of reagents, antibiotic solutions in 96-well microplates were frozen at -20℃ to evaluate their useful storage periods.

Methods:Various concentrations of metronidazole(MTZ) and clarithromycin(CLR) solutions were divided into ten plates of 96-well microplates, sealed and stored at -20℃. The broth microdilution susceptibility test was done with fresh and preserved antibiotic dilutions each month on 5 occasions for 4 strains(initial minimum inhibitory concentration(MIC) for MTZ 1, 4, 16, 64 ug/mL, initial MIC for CLR <0.125, <0.125, <0.125, 32 ug/mL) of H. pylori. The difference of MIC values of more than ±2 log2 dilution was considered significant.

Results:For both MTZ and CLR, the difference of MIC values of fresh and frozen antibiotic solutions was within ±1 log2 dilution and the results of susceptibility test were the same for 7 months.

Conclusions:Various concentrations of frozen MTZ and CLR solutions could be used for at least 7 months for the antimicrobial susceptibility testing of H. pylori. 

[in Korean]

Original article

Home-made Rapid Urease Test for Detection of Helicobacter pylori Infection

Jongwook Lee, M.D., Soo Hwan Pai, M.D., Jong Hyun Nahm, M.D., Jong Won Choi M.D., Bum Su Kim, M.D., Won Choi, M.D., Don Haeng Lee, M.D., Hyung Gil Kim, M.D. and Young Soo Kim, M.D.

Ann Clin Microbiol 1999 March, 2(1): 54-57. Published on 20 March 1999.

Background:The rapid urease test has been widely used for detection of Helicobacter pylori infection because it is easy, simple and rapid result. The CLO test and PyloriTek test observe color changes after the gastric biopsy specimens are inerted into the test kits. Because H. pylori is not evenly distributed in the gastric mucosa, grinding or mincing of gastric specimens prior to culture enhances isolation rate of H. pylori. Therefore, we evaluated the effects of rubbing the gastric biopsy specimens onto the urea soaked filter paper in this home-made rapid urease test.

Methods:Forty-three patients referred for upper gastrointestinal tract endoscopy were evaluated for H. pylori infection. The home-made rapid urease test was prepared by soaking a piece of Whatman No. 2 filter paper in 2% urea agar. We compared the results of the home-made rapid urease test with histologic examination, gram stain, CLO test and culture.

Results:Of forty-three patients, 28 were found to be H. pylori-positive either by gram stain or by culture. The sensitivity and specificity of CLO test, based on the results of gram stain and culture were 85.7% and 92.9%. The sensitivity and specificity of home-made rapid urease test, based on the results of gram stain and culture were 92.9% and 92.9%.

Conclusions:The home-made rapid urease test is faster and shows a high sensitivity and specificity. 

[in Korean]

Original article

Identification and Biochemical Reactions of Enterococci by a Simplified Identification System

Young Uh, In Ho Jang, Gyu Yel Hwang, Kap Jun Yoon and Hyung-Hoan Lee

Ann Clin Microbiol 1999 March, 2(1): 58-63. Published on 20 March 1999.

Background:The accurate and rapid identification of enterococci can provide clinician’s decision making of antimicrobial therapy because enterococci are usually multiresistant to commonly used antimicrobial agents and antimicrobial resistance patterns are different according to enterococcal species. Accuracy of identification system depends mainly on data base such as positive rate of biochemical reactions, relative frequency of occurrence of biotype, and isolation frequency of microorganisms. The purpose of this study was to analyze the isolation rate and biotype frequency of enterococci isolated from clinical specimens.

Methods:We used a simplified identification system for the identification of the enterococci from clinical specimens during the period of June 1998 to November 1998. Biochemical phenotypes of 500 isolates of enterococci were also analyzed by a simplified identification system consisting of eight conventional biochemical tests.

Results:Enterococci were isolated from urine (36.4%), wound (35.0%) and blood (7.2%) in order of decreasing frequency. Among the isolates, 67.8% were E. faecalis, 23.0% E. faecium, 2.2% E. hirae/durans, 2.0% E. casseliflavus, and 1.0% E. hirae. The simplified identification system of enterococci identified 93.6% of all isolates to species level. The system identified 98.5% of E. faecalis but only 89.6% of E. faecium.

Conclusions:Our simplified identification system based on eight biochemical tests offer a simple, reliable and economic method for the identification of clinical isolates of enterococci, but further studies are needed for the improvement of accuracy and identification rate. 

[in Korean]

Original article

Antimicrobial Resistance and Serotypes in the Clinical Isolates of Group B Streptococci

Young Uh, M.D., In Ho Jang, M.D., Gyu Yel Hwang, M.D. and Kap Jun Yoon, M.D.

Ann Clin Microbiol 1999 March, 2(1): 64-70. Published on 20 March 1999.

Background:This study is designed to provide data on the trend of resistance by year of isolation in the clinical isolates of group B streptococci(GBS) during recent eight years and to elucidate the relationship between serotypes and antimicrobial resistance patterns.

Methods:The minimal inhibitory concentrations (MIC) of seven antimicrobial agents and serotypes for 150 strains of GBS isolated from clinical specimens between 1990 and 1997 were investigated.

Results:The resistance rate of 150 clinical isolates of GBS were 20.0% to clindamycin, 16.0% to erythromycin, 4.0% to chloramphenicol, and 95.3% to tetracycline. None was resistant to penicillin, ceftriaxone, or vancomycin. Of the 24 isolates resistant to erythromycin, 20 (83.3%) were resistant to clindamycin. Resistance rates of erythromycin according to serotypes in decreasing order were 69.2% (V), 23.2% (III), and 3.5% (Ib). All serotypes Ia and II were susceptible to erythromycin and clindamycin.

Conclusions:Striking emergence of resistant strains to erythromycin and clindamycin in our clinical isolates of GBS was mainly due to sudden increase of serotype V and III which shows multi-drug resistance phenotype.

[in Korean]

Original article

Use of Methyl-α-D-glucopyranoside Test for Species Identification of Vancomycin Resistant Enterococci

Mi-Na Kim, M.D., Heung-Sub Sung, M.D., Jun Seok Park, M.D. and Chik Hyun Pai, M.D.

Ann Clin Microbiol 1999 March, 2(1): 71-76. Published on 20 March 1999.

Background:The precise identification of Enterococcus gallinarum and E. casseliflavus has assumed additional importance in clinical microbiology due to the intrinsic low-level resistance to vancomycin and the difficulty in differentiating them from E. faecium or E. faecalis, which are frequently found to be clinically significant vancomycin resistant enterococci(VRE). We evaluated the usefulness of Methyl-α-D-glucopyranoside(MDG) test for accurate species identification among them.

Methods:A total of 23 enterococci isolates including 18 clinical isolates of VRE from Nov 1997 to Aug 1998 and 5 VRE strains which had previously been reported as E. faecalis (2), E. faecium(2), E. avium(1) carrying vanC were tested for acidification of MDG. MDG test was done using 1% MDG in phenol red broth base and yellow coloration was interpreted as positive after 1 and 2 days of incubation at 35℃. MDG results were compared with species identification by MicroScan Pos Combo type 6 (Dade, USA), motility test, pigment production, and PCR results of vanA, vanB, vanC1, vanC2/C3. 

Results:Vancomycin resistance of 23 strains were genotyped as 7 strains of vanA, 12 strains of vanC1, 4 strains of vanC2/C3. MicroScan identified 7 vanA VRE as E. faecalis(1) and E. faecium(6), 12 VRE carrying vanC1 as E. faecalis(3), E. faecium(8) and E. avium(1), and 4 VRE carrying vanC2/C3 as E. faecalis(3) and E. avium(1). Sixteen vanC VRE strains were all positive for MDG test and only 8(50%) of the 16 strains were motile. Yellow pigment were detected in all 4 vanC2/C3 VRE but only after a careful examination with a prolonged incubation. Seven vanA VRE were all negative in MDG tests, motility test and pigment production.

Conclusions:MicroScan system plus motility and pigment production test was not able to differentiate reliably E. gallinarum and E. casseliflavus from E. faecalis and E. faecium. The MDG test was shown to be superior to motility test in differentiating those from E. faecalis and E. faecium. We conclude that the MDG test should be included for identifcation of VRE.

[in Korean]

Original article

Detection of Toxin B Gene of Clostridium difficile by Polymerase Chain Reaction from Clinical Isolates

Hyukmin Lee, M.D., Young Ah Kim, M.D., Kwang Il Park, M.D., Kyungwon Lee, M.D. and Yunsop Chong, Ph.D.

Ann Clin Microbiol 1999 March, 2(1): 77-81. Published on 20 March 1999.

Background:Clostridium difficile causes antibiotic-associated diarrhea or pseudomembranous colitis by producing of toxins in patients treated with antimicrobial agents. Stool cultures for C. difficile and tests for the presence of its toxin are the most widely used methods for the diagnosis of infection. The aim of this study was to determine the usefulness of polymerase chain reaction for the detection of toxin B gene from C. difficile isolates.

Methods:In this study, 85 strains of C. difficile were used, which were isolated from stool specimens of patients with suspected antibiotic-associated diarrhea or pseudomembranous colitis from 1987 to 1994 using cefoxitin-cycloserine-fructose agar. DNA of the C. difficile isolates was extracted by boiling and by conventional methods. The primers used for toxin B gene amplification were YT-17, 5′-GGTGGAGCTTCAATTGGAGAG-3′ and YT-18, 5’GTGTAACCTACTTTCATAACACCAG-3′. Amplification products were electrophoresed in a 1% agarose gel containing ethidium bromide and the presence of the 399 bp band was examined under ultraviolet light. The results were compared with those of toxin A detection by PCR and with the results of quantitative cultures.

Results:Toxin B gene was detected in 74% (63/85) of the C. difficile isolates. Toxin B gene was detected in all strains with toxin A gene, but not in the strains without toxin A gene. DNA extraction by boiling and by conventional methods gave the same detection rate. The positive rate of toxin B gene was slightly higher in the strains which were isolated with a higher colony count from stool than nontoxigenic ones.

Conclusions:The PCR detection of toxin B gene is a useful method for identifying the toxigenic C. difficile strain in the clinical laboratory, and the boiling method is simple for DNA extraction. The use of a toxin test can reduce false positive diagnosis due to the presence of nontoxigenic strains among the isolates. 

[in Korean]

Original article

The Prevalence of Hepatitis G Virus by Reverse Transcription-Polymerase Chain Reaction

Kyung Dong Kim, M.D., Hee Soon Cho, M.D., Jin Young Moon M.D. and Chae Hoon Lee, M.D.

Ann Clin Microbiol 1999 March, 2(1): 82-88. Published on 20 March 1999.

Background:Hepatitis G virus(HGV) is known to be associated with non-A-E hepatitis but pathogenic relevance and mode of transmission are still unclear. In this study, we analyzed the prevalence and clinical implications of HGV infection in patients on hemodialysis or being treated for hematologic disease, and healthy controls.

Methods: HGV RNA was identified in serum by reverse transcription-polymerase chain reaction(RT-PCR) with nested primers deduced from highly conserved area of the 5′-untranslated region. Other parenterally transmissible hepatitis viral markers(HBsAg and anti-HCV) and alanine aminotransferase(ALT), history of transfusion, duration of hemodialysis were assessed.

Results:HGV RNA was detected in 12.5%(8 of 64) of the patients on hemodialysis and in 24.1%(14 of 58) of the patients treated for hematologic disease, as compared with 0.8%(1 of 120) of healthy controls(P<0.05). HBsAg, anti-HCV, ALT level, rate of transfusion history and duration of hemodialysis were not significantly different between HGV-infected patients and non-HGV-infected patients. In patients treated for hematologic disease, sex was significantly different between HGV positive and negative groups.

Conclusions:Patients on hemodialysis and being treated for hematologic disease have increased risk for HGV infection, but there was no clinical difference between HGV RNA positive and negative groups. HGV infection itself does not seem to be a frequent cause of liver disease in these patients. The clinical significance of long-term infection with HGV remains to be established. 

[in Korean]

Original article

Detection of Serum HCV RNA by Rapid Cycle PCR Using Hot Air Thermocycler with Capillary Tubes

Mi Yae Youn, M.D., Hye Soo Lee, M.D., Dal Sik Kim, M.D., Sam Im Choi, M.D. and Carl T. Wittwer, M.D.

Ann Clin Microbiol 1999 March, 2(1): 89-94. Published on 20 March 1999.

Background:Reverse transcription-polymerase chain reaction (RT-PCR) is the most sensitive method for the detection of Hepatitis C virus (HCV) RNA from serum. The PCR by conventional heat block thermocycler using small plastic tube is time and reagent consuming procedure, but rapid cycle PCR (RPCR) by hot air thermocycler using glass capillary tube is very rapid and economic. Therefore, RPCR have been recognized as a very convenient method for routine diagnostic test in clinical laboratories, but there are few reports about its usage for the detection of HCV RNA.

Methods:We selected two sets of primer pair from 5’noncoding region of HCV RNA genome, and optimized RPCR condition using hot air rapid thermocycler with master mix in capillary tubes. And RT-RPCR for detection of HCV RNA were performed on the serum of 58 patients, which were tested anti-HCV antibody by EIA.

Results:The optimized RPCR conditions were: denaturation; 94℃ for “0” sec, annealing; 55℃ (first) and 50℃ (nested) for “0” sec, elongation; 72℃ for “0” sec, and amplification cycles were 30 cycles. The consuming times per cycle were 30 sec (first) and 40 sec (nested), respectively, so the total involving times for nested RPCR were 35 min. Of the 42 EIA positive samples, 26 (62%) were RT-RPCR positive.

Conclusions:RT-RPCR using hot air thermocycler with glass capillary tubes for detection of HCV RNA in serum is very rapid and economic than conventional PCR using heat block thermocycler. Therefore HCV RNA detection by RT-RPCR appears to be very useful for routine clinical laboratory diagnostic method. 

[in Korean]

Case report

A Case of Infective Endocarditis Caused by Haemophilus paraphrophilus

Myoung Youn, M.D., Jong Hee Shin, M.D., Soon Pal Suh, M.D. and Dong Wook Ryang, M.D.

Ann Clin Microbiol 1999 March, 2(1): 95-100. Published on 20 March 1999.

Haemophilus paraphrophilus is a normal inhabitant of the naso- and oropharynx and has been rarely reported as a cause of endocarditis. H. paraphrophilus is a slow-growing and fastidious gram-negative bacterium and belongs to the HACEK group. We experienced a case of infective endocarditis due to H. paraphrophilus. The organism was repeatedly isolated from the blood cultures of a 60 year-old patient presenting with high fever, chills, cardiac murmur, and change of mental state. The patient had a history of mitral and tricuspid valve replacements and had been followed up for complications of cirrhosis of liver such as esophageal varix and oral bleeding. The isolate was identified as H. paraphrophilus by the characteristics, including factor V requirement, negative indole, urea and ornithine decarboxylase and acid production from glucose and lactose. Antimicrobial susceptibility testing by the disk diffusion method showed that the organism was susceptible to ampicillin, chloramphenicol, tetracycline, trimethoprim/sulfamethoxazole, cefotaxime, ceftazidime, aztreonam, imipenem, and ciprofloxacin. The patient expired on hospital day 8, probably due to complications of cirrhosis of liver. To our knowledge, this is the first case of infective endocarditis caused by H. paraphrophilus in Korea.

[in Korean]

Case report

Chryseobacterium indologenes Isolated from Clinical Specimens

Seong Kyu Lee, M.D. and Nam Yong Lee, M.D.

Ann Clin Microbiol 1999 March, 2(1): 101-104. Published on 20 March 1999.

Chryseobacterium indologenes is a nonfastidious, oxidase-positive, gram-negative rod that does not ferment glucose. It is known to be associated with a variety of clinical infections. We report six cases of C. indologenes isolated from clinical specimens, which were seen at our institution over a 2-year period. These organisms were recovered from blood, pleural fluid, peritoneal fluid, bile, endotracheal aspirate, and sputum. We described clinical characteristics, treatment outcome, microbiological characteristics, and in vitro antibiotic susceptibility test.

[in Korean]