Do-Young Song, and Won-Kil Lee
Ann Clin Microbiol 2005 April, 8(2): 105-112. Published on 20 October 2005.
An international outbreak of severe acute respiratory syndrome (SARS), a recently recognized syndrome caused by the newly identified severe acute respiratory syndrome-associated coronavirus (SARS-CoV), began in November 2002 and ended in July 2003. Coronavirus is a family of enveloped, single stranded-RNA viruses causing disease in humans and animals, but the other known coronaviruses that affect humans cause only the common cold. The number of SARS cases in 2003 was approximately 8000 across the world. Many recent studies have reinforced initial impressions that SARS-CoV is primarily transported via contact and/or droplets and that the combination of standard, contact, and droplet precautions is generally effective for its control. Active surveillance for clusters of cases of severe respiratory disease must be a first priority, especially among health care workers. Such surveillance should include the rapid diagnosis and prevention of other respiratory viruses that cause outbreaks of febrile respiratory disease-notably, influenza. Surveillance on the part of clinicians is the key to the early detection of any reemergence before it regains a foothold in the community. During the outbreak of SARS, ribavirin, steroids, interferon, convalescent plasma, and lopinavir/ itonavir were used in varying doses and combinations in different regions of the world. At present no definitive conclusions regarding the efficacy of any of these treatments can be drawn. New findings regarding SARS are continuing to be discovered at an unprecedented pace, permitting a better understanding of the disease and enabling better preparation for its possible returns.
[in Korean]
Heungsup Sung, Hee Jung Chung, Yeon Jung Pyo, Seung Namgoong, and Mi-Na Kim
Ann Clin Microbiol 2005 April, 8(2): 113-120. Published on 20 October 2005.
Background: Because the mortality rate of invasive aspergillosis (IA) is more than 50%, an early diagnosis and appropriate management are important to achieve a favorable outcome. Aspergillus galactomannan (AG) antigen test has recently been introduced for diagnosis and monitoring of IA. This study was to evaluate the clinical utility of AG detection in diagnosis of IA.
Methods: One hundred and seventy-five samples from 149 patients were tested for AG during the period from September 2004 to May 2005 and the results were evaluated retrospectively. IA was diagnosed into ‘proven’, ‘probable’and ‘possible’,groups based on patients’clinical laboratory findings as per European Organization for Research and Treatment of Cancer/Mycoses Study Group. AG was tested using a Platelia Aspergillus antigen ELISA (Bio-Rad, Hercules, CA, USA); the optical density (OD) of the test specimen was divided by the mean OD of two cut-off controls. The test was classified as positive when the OD ratio was ≥1.5; ratios 1-1.5 were classified as equivocal. Clinical Information was obtained from the electronic medical records of the patients.
Results: Of the 175 samples tested, 19 were positive, 14 equivocal, and 142 negative for AG. A number of the ‘proven’, ‘probable’, and ‘possible’IA patients were 2, 15, and 28, respectively. At the OD ratio of 1.5, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 76.9%, 94.7%, 58.8%, and 97.7%, respectively, when 4 false-negative patients treated with amphotericin B before Aspergillus antigen test were excluded.
Conclusion: The Platelia Aspergillus ELISA demonstrated an excellent sensitivity, specificity and NPV for the diagnosis of IA. A combined use of the antigen test with microbiological and clinical evaluation might facilitate the early diagnosis of IA and, consequently, improve its clinical outcome.
[in Korean]
Kwang Ok Park, Han Chul Son, Il Kwon Bae, and Seok Hoon Jeong
Ann Clin Microbiol 2005 April, 8(2): 121-129. Published on 20 October 2005.
Background: The purposes of this study were to investigate the prevalence of imipenem-resistant clinical Acinetobacter baumannii isolates and to determine the mechanism of the resistance.
Methods: During the period of June to September 2004, susceptibility to imipenem of A. baumannii isolates from a hospital in Busan, Korea were investigated. The isolates were screened for the production of carbapenemase and metallo-β-lactamase by Modified-Hodge and EDTA-disk synergy tests, respectively; minimum inhibitory concentrations (MICs) were determined by agar dilution method. Genes coding for GES, IMP, VIM, SMP-1, GIM-1 and OXA type β-lactamases were searched by PCR amplification, and the PCR products were subjected to direct sequencing. Isoelectric points of β-lactamases were estimated by isoelectric focusing and the epidemiological relationships of isolates were investigated by enterobacterial repetitive intergenic consensus (ERIC) PCR.
Results: Fifty eight strains of A. baumannii were isolated from clinical specimens during the surveillance period, and 14 isolates (24.1%) were resistant to imipenem. Of the 14 isolates, 9 were tested positive in Modified-Hodge test and 2 were also positive in EDTA-disk synergy test. Genes encoding OXA-23 and IMP-1 were detected in 7 and 2 isolates, respectively. In IEF studies, OXA-23 and IMP-1 enzymes had corresponding pIs at 6.7 and 9.0, respectively. Seven OXA-23-producing and 2 IMP-1-producing isolates showed the same ERIC PCR patterns.
Conclusion: It is concluded that 7 and 2 A. baumannii isolates from the patients in a hospital in Busan acquired resistance to imipenem by producing OXA-23 and IMP-1 β-lactamases, respectively. The isolates producing these β-lactamases might be originated from a common source.
[in Korean]
Bo-Moon Shin, and Eun-Joo Lee
Ann Clin Microbiol 2005 April, 8(2): 130-135. Published on 20 October 2005.
Background: Clostidium difficile is one of the most important pathogens responsible for nosocomial diarrhea; therefore, we compared the efficacy of laboratory tests for diagnosing C. difficile diarrhea.
Methods: We evaluated 107 stool specimens using a latex agglutination test (LA) (BD CDT, Culturette CDT, Becton, Dickison and Company, USA) and an enzyme linked fluorescent immunoassay (ELFA) (VIDAS C. difficile Toxin A II, Bio-Merieux sa, Marcy-l’Etoile, France). Stool specimens were cultured using cycloserine cefoxitine fructose agar in anaerobic condition. For identification of C. difficile, spore stain and Vitek ANA identification card (Bio-Merieux sa) were used. Toxin A and toxin B genes were analysed by PCRs using primers NK3-NK2 and NK104N-K105 respectively.
Results: The concordance rate between LA and ELFA was 68.2%. Based on the culture results, the sensitivity/specificity of LA and ELFA were 54.8%/100% and 17.8%/100%, respectively. The positive rates of toxin A and B genes were both 90.4% (66/73). Based on the results of PCR assays for toxin A and B genes, the sensitivity/specificity of LA and ELFA were 37.9%/85.7% and 19.7%/ 100%, respectively. C
Conclusion: Based on C. difficile culture and toxin A and B gene PCR results, the sensitivity of LA was apparently higher than that of ELFA. However, it should not be simply estimated that ELFA has lower capability for detecting toxin A of C. difficile because the possibility of emerging variant strains of C. difficile could not be ruled out. The prevalence of toxigenic strains of C. difficile including variant strains should be studied in Korea.
[in Korean]
Chong Rae Cho, Tae Hyun Um, and In Ki Paik
Ann Clin Microbiol 2005 April, 8(2): 136-141. Published on 20 October 2005.
Background: Yersinia pseudotuberculosis is recognized throughout the world as a cause of water- or food born infections in human and animals. Although many attempts have been made to define optimal conditions for the isolation of the organism from water, their isolation yields remain low; therefore, we tried to find an effective method for the recovery of Y. pseudotuberculosis from water.
Methods: Water samples were deliberately contaminated with Y. pseudotuberculosis at various levels and then processed by the following three isolation methods: centrifugation, direct filtration, and intracellular culture. For the centrifugation method, the water samples were centrifuged at 5000 rpm for 1 hr and the final precipitates were inoculated in cefsulodin-irgasan-novobiocin (CIN) media. For the filtration method, the water samples were filtered by negative pressure and the filter papers were put directly on CIN media. For the intracellular culture method, the organisms were extracted from the HeLa cells that had been infected with Y. pseudotuberculosis and inoculated on CIN media. We also examined the efficacy of the filtration method after cold enrichment with a mixture of Y. pseudotuberculosis, Escherichia coli, and Citrobacter freundii.
Results: With the concentration of 3×102/100 mL, Y. pseudotuberculosis was isolated only by the filtration method; however, none of the culture methods were good enough to recover the organism from the water sample when the concentration was 3×10/100 mL. With cold enrichment, however, the recovery was much more efficient; the organism grew after direct inoculation or after filter inoculation when the starting concentrations were 3×102/100 mL or 3×10/100 mL, respectively.
Conclusion: A combined use of direct filtration and filter inoculation after cold enrichment is the most effective method to yield Y. pseudotuberculosis isolation. The introduction of effective methods for the isolation of Y. pseudotuberculosis from untreated drinking water would increase the awareness by the public of the health hazard of spring water.
[in Korean]
Jeong Hwan Shin, Hye Ran Kim, Hi Ryune Lee, Jae Il Chung, Kweonsik Min, Chi Sook Moon, Seong Mi Ryu, and Jeong Nyeo Lee
Ann Clin Microbiol 2005 April, 8(2): 142-147. Published on 20 October 2005.
Background: Resistant organisms are now a growing and frequent problem in community-acquired infections. There is little information on the etiology and antimicrobial susceptibility patterns of community-acquired urinary tract infection (CA-UTI) at a tertiary-care hospital.
Methods: We evaluated the distribution of etiological organisms with their antimicrobial susceptibility patterns of CA-UTI in the patients visiting a tertiary-care hospital during the period of three years from 2001 through 2003.
Results: In total, 1,753 bacterial isolates yielded a significant growth as pathogens of CA-UTI in this study. The most common pathogen was Escherichia coli(38.3%), followed by Pseudomonas aeruginosa(10.8%), Enterococcus faecalis(7.3%), Klebsiella pneumoniae(6.4%), coagulase negative staphylococci (CoNS) (5.4%) and Staphylococcus aureus(5.2%). The prevalence of E. coli was significantly higher in females (P< 0.001), whereas P. aeruginosa, E. faecalis,and S. aureus were significantly more common in male group (P< 0.001). The susceptibility rate of E. coli was 26.0% to ampicillin, 65.8% to gentamicin, 51.3% to co-trimoxazole, and 62.5% to ciprofloxacin. The susceptibility patterns of Enterobacteriaceae other than E. coli were different from those of E. coli. Extended spectrum beta-lactamase was detected in 7.9% of E. coli and 15.6% of K. pneumoniae.
Conclusion: This study demonstrates a diversity of etiological organisms and a high rate of resistance to commonly used antimicrobials of CA-UTI in patients visiting a tertiary-care hospital.
[in Korean]
Dae-Dong Lee, Sun-Min Lee, Jae-Cheol Choi, Eun-Yup Lee, and Chulhun L. Chang
Ann Clin Microbiol 2005 April, 8(2): 148-152. Published on 20 October 2005.
Background: This study was designed to evaluate the performance of FAN-aerobic bottles (FANA) in comparison with standard-aerobic bottles (STD-A) in BacT/Alert3D blood culture system.
Methods: A total of 596 pairs of blood cultures, submitted from Emergency Department of Pusan National University Hospital between July and December 2004, were evaluated. In addition to the routine blood culture protocol using standard blood culture bottles, 5 ml of blood samples was inoculated into FAN-A bottles for this study.
Results: Microorganisms were grown in 84 (14.1%) of 596 cultures; of those, 15 were positive in STD-A only (2.5%), 35 in FAN-A only (5.9%), and 34 in both (5.7%). The positive rate in FAN-A bottles was significantly higher than that in STD-A bottles (P<0.001). The species of isolates and detection time showed no difference between the blood culture bottles.
Conclusion: In the BacT/Alert3D blood culture system, the use of FAN-A bottles instead of the standard aerobic bottles should yield a higher positive rate.
[in Korean]
Junyoung Kim, Seonghan Kim, Semi Jeon, Yeonho Kang, Duyoung Jeon, Jungbeom Kim, and Bokkwon Lee
Ann Clin Microbiol 2005 April, 8(2): 153-159. Published on 20 October 2005.
Background: In May 2004, an outbreak of a diarrheal disease occurred among tourists returning from Mt. Geumgang in North Korea; Shigella dysenteriae type 8 was isolated from 12 of the 36 patients who were suffering from diarrhea. We investigated the genetic relatedness of the isolates.
Methods: The isolates were identified by VITEK system and serotyped by a slide agglutination test. Antimicrobial susceptibility was determined by the disk diffusion method and genetic relatedness was examined by pulsed-field gel electrophoresis (PFGE).
Results: All 12 isolates were identified as Shigella spp., and agglutinated by S. dysenteriae type 8 antisera. All of these isolates showed the same antibiotic susceptibility pattern, and were resistant to streptomycin, tetracycline and trimethoprim/sulfamethoxazole. PFGE patterns were classified into 2 types, sdx1 and sdx2, and the relatedness between these two types was 80.5%. Eleven isolates belonged to sdx1.
Conclusion: The antibiotic susceptibility pattern and genetic relatedness of the isolates strongly suggest that they were from the same origin. Because this is the first report of S. dysenteriae type 8 isolation in Korea, and all of these cases were related to foreign travel, the surveillance system and the ability of the clinical laboratory should be strengthened to prevent the entry and spread of rare and hitherto not reported infectious agents into Korea.
[in Korean]
Wonkeun Song, Tae Jae Lee, Taek-Kyung Kim, Han-Sung Kim, Jae-Seok Kim, Min-Jeong Park, and Kyu Man Lee
Ann Clin Microbiol 2005 April, 8(2): 160-164. Published on 20 October 2005.
Background: The aim of this study was to evaluate the Vitek system and the disk diffusion method for susceptibility testing of Enterobacteriaceae against piperacillin-tazobactam (TZP) and methicillin-resistant Staphylococcus aureus(MRSA) against trimethoprim-sulfamethoxazole (SXT) using the broth microdilution method as the reference.
Methods: Using the Vitek system and the disk diffusion method, we tested 96 isolates of Enterobacteriaceae (48 Escherichia coli, 26 Klebsiella pneumoniae, 8 Serratia marcescens, 6 Enterobacter cloacae, 2 E. aerogenes, 2 K. oxytoca, 2 Citrobacter freundii, 2 Pantoea agglomerans) and 61 isolates of MRSA for susceptibity against TZP and SXT, respectively; the broth microdilution of National Committee for Clinical Laboratory Standards was used as the reference method.
Results: In the susceptibility testing of Enterobacteriaceae against TZP, Vitek system yielded 10 (10%) minor errors, and the disk diffusion method one (1%) very major and 13 (14%) minor errors. For the MRSA against SXT, the rate of categorical agreement between the reference method and the Vitek or the disk diffusion method was both 100%. The rates of agreement between the reference method and the Vitek system in term of MICs (within ±1 dilution) were 93% and 98% in the susceptibility testing of Enterobacteriaceae against TZP and MRSA against SXT, respectively.
Conclusion: Both Vitek system and disk diffusion method showed an acceptable level of accuracy for the susceptibility test of Enterobacteriaceae against TZP and MRSA against SXT.
[in Korean]
Mi-Yeon Lee, Young-Woo Gong, Bo-Yong Oh, Seung-Hye Jung, Hye-Young Kim, and Jea-Mann Lee
Ann Clin Microbiol 2005 April, 8(2): 165-171. Published on 20 October 2005.
Background: Influenza is a highly contagious respiratory disease. Influenza virus, which causes epidemics every winter season, has the high possibility of appearing with new virus types every year due to antigen variation. Therefore, we intended to analyze the data on the epidemiology of influenza that had been acquired by laboratory surveillance in Incheon during the 2003/2004 and 2004/ 2005 seasons and to apply the knowledge to the control and prevention of influenza in Korea.
Methods: Specimens were inoculated into Madin-Darby canine kidney (MDCK) cells and, when cytopathic effect (CPE) was seen, culture supernatants were tested by mutiplex RT-PCR for typing and subtyping of influenza viruses.
Results: The first virus of the season was isolated at week 47 (3rd week on November) in 2003 during 2003/2004 and at week 43 (4th week on October) in 2004 during 2004/2005, which was about 4 weeks earlier than in the 2003/2004 season. From 532 specimens cultured for influenza virus during the 2003/2004 season. 330 (62.0%) viruses were isolated: 161 (48.8%) A/H3N2, 1 (0.3%) A/H1N1, and 168 (50.9%) B. During 2004/2005 season, 457 specimens were tested and 278 (60.8 %) were positive for influenza virus: 232 (83.5%) A/H3N2, 5 (1.8%) A/H1N1, and 38 (13.7%) B. The incidence of influenza was the highest in the school-age children and young adults of 7 to 19 years age group in both seasons.
Conclusion: Influenza virus was isolated at a high rate (more than 60%) by the laboratory influenza surveillance system in Incheon during the 2003/2004 and 2004/2005 seasons: the predominant strain was influenza A/H3N2 subtype.
[in Korean]
Jin Hong Park, Ji Young Moon, Chulhun L. Chang, and Yung Bu Kim
Ann Clin Microbiol 2005 April, 8(2): 172-178. Published on 20 October 2005.
Background: Most of the shigellosis outbreaks in Korea have been caused by Shigella sonnei since late 1990’s. We analyzed 36 strains of S. sonnei isolated in South Korea from 1998 to 2001 by molecular epidemiologic tools to understand genetic relationship of the outbreaks.
Methods: The 36 strains of S. sonnei were tested for the presence of virulence genes (ial, ipaH, stx, set1A, set1B and sen) using polymerase chain reaction (PCR) method and for the production of Shiga-toxin using latex agglutination test. Seventeen representative strains were selected and their genetic relevance was analyzed by plasmid profile and pulsed-field gel electrophoresis(PFGE).
Results: By PCR, ipaH gene was detected in all 36 strains, set1B gene in 15 strains (41.7%), and sen gene in 16 strains (44.4%); all strains were negative for set1A gene. Although stx gene was positive in four strains by PCR method, the toxin was negative by latex agglutination test. The strains were differentiated into 11 groups by plasmid profile and 1 type with 3 subtypes (A-1, A-2 and A-3) by PFGE.
Conclusion: There was a wide range of diverse virulence genes present in the outbreak strains of S. sonnei. PFGE analysis indicated that all the strains tested were related with each other despite minor genotypic and phenotypic differences. A genetically identical clone of S. sonnei was estimated to be the cause of the outbreaks.
[in Korean]
Bong Joon Oh , Jong Hee Shin, Dong Hyun Shin, Sook In Jeong, Hyung Joon Kim, Soon Pal Suh, and Dong Wook Ryang
Ann Clin Microbiol 2005 April, 8(2): 179-184. Published on 20 October 2005.
Trichosporon beigelii is often resistant to the fungicidal effect of amphotericin B and can cause fatal disseminated infections in immunocompromised patients. We report a case of a disseminated T. beigelii infection with a favorable outcome in a patient with acute erythroleukemia and neutropenia. The patient presented a persistent fever, multiple erythematous skin lesions, and pulmonary infiltrates. T. beigelii was isolated from blood cultures in four days and also from cultures of abdominal skin lesion, sputum, and stool. The isolate was resistant to amphotericin B (MIC, 2 μg/mL), and the respective fluconazole and itraconazole MICs were 4 and 1 μg/mL. The patient was successfully treated with fluconazole plus amphotericin B in combination with granulocyte colony stimulating factor and leukocyte transfusion. This case shows the importance of early diagnosis and treatment with combination of amphotericin B and fluconazole as a prognostic factor of disseminated T. beigelii infections.
[in Korean]
Chong-Rae Cho, Tae-Hyun Um, and Jae-Won Jeong
Ann Clin Microbiol 2005 April, 8(2): 185-188. Published on 20 October 2005.
There are two stages in the life circle of Plasmodium spp in humans: exoerythrocytic and erythrocytic stages. Hydroxychloroquine is the major chemotherapeutic agent against malarial parasites in their erythrocytic stage. The recurrence of Plasmodium vivax malaria, which is usually caused by an inadequate treatment or the presence of drug resistant parasites, has been reported frequently in the world, but rarely in Korea. We experienced two patients who recurred with P. vivax malaria after hydroxychloroquine therapy, and treating with insufficient doses of the drug was suspected as the cause of the recurrence.
[in Korean]
Bong Joon Oh, Jong Hee Shin, Kwang Jin Kim, Duck Cho, Seong Jung Kee, Myung Gun Shin, Soon Pal Suh, and Dong Wook Ryang
Ann Clin Microbiol 2005 April, 8(2): 189-193. Published on 20 October 2005.
Fusarium species are representative of the emerging group of filamentous molds, which cause respiratory and disseminated infections in immunocompromised patients. To date, only five cases of respiratory or disseminated skin infections due to Fusarium spp. have been described in Korea. Here we describe a fungemia case of Fusarium oxysporum in a 3-year old boy who was neutropenic following chemotheray for leukemia. Fever, painful macules on both extremities and phlebitis on the site of venous blood sampling developed on the day 35 of admission. All four blood cultures obtained on hospital days 37, 38, 40 and 42 yielded the same F. oxysporum. The infection was cured with a high dose (1.5 mg/kg) of amphotericin B. This case shows that Fusarium is among a few filamentous fungi that cause clinically detectable fungemias in immuncompromised hosts.
[in Korean]
Goeun Lee, Jeeyong Kim, Kyung Hee Kim, Jung Ah Kwon, Yunjung Cho, Young Kee Kim, Kap No Lee, and Chang Kyu Lee
Ann Clin Microbiol 2005 April, 8(2): 194-197. Published on 20 October 2005.
Scedosporium prolificans is a saprophytic fungus widespread in the environment. It has become an emerging pathogen in recent years causing disseminated infections, especially in profoundly neutropenic immunocompromised patients. We report a case of fatal Scedosporium fungemia in a 45 year old female with acute myeloid leukemia in relapse. She received salvage chemotherapy and antibiotic treatment, and was neutropenic with relapsing fever. S. prolificans was isolated repeatedly from the aerobic bottles on the second day of two successive blood cultures. Amphotercin B was started; however, the patient expired the next day.
[in Korean]
Nam Hee Ryoo, Won Mok Lee, Jung Sook Ha, Dong Suk Jeon, Jae Ryong Kim, Dae Gu Sohn and Shin Woo Kim
Ann Clin Microbiol 2005 April, 8(2): 198-201. Published on 20 October 2005.
A 36-year-old female who initially presented with a small erythematous and swollen abscess on her left anterior tibial area was found out to have a cutaneous Mycobacterium abscessus infection. She was first treated with incision and drainage, dressing, and antibiotics. The lesion began to be aggravated and dispersed. Neither aerobic nor anaerobic bacteria was grown on blood agar plate. After a few weeks, Mycobacterium grew on Ogawa media after 6 days, and was identified as M. abscessus by PCR-restriction fragment length polymorphism. She was then treated with clarithromycin, levofloxacin, and amikacin, and the skin lesion was resolved without further recurrence.
[in Korean]
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