Distribution of adeG, adeB, adeE, adeY, abeM, and adeJ Efflux Pump Genes in Clinical Isolates of Acinetobacter Species from Korea

BACKGROUND: The aim of the present study was to determine the frequency of six efflux pump genes in Acinetobacter clinical isolates collected from South Korean hospitals. METHODS: In this study, we used a total of 339 Acinetobacter strains, comprising 279 Acinetobacter calcoaceticus–Acinetobacter baumannii (ACB) complex and 60 non-ACB complex strains. We performed specific PCR assays to detect adeG, adeB, adeE, adeY, abeM, and adeJ, transporter genes of the multidrug efflux pumps AdeFGH, AdeABC, AdeDE, AdeXYZ, AbeM, and AdeIJK, respectively. RESULTS: Frequencies of six efflux pump genes varied according to the species of Acinetobacter. Frequencies of adeE, abeM, and adeJ between A. baumannii group and A. nosocomialis group were found to be significantly different. Significant differences were found in the frequencies of adeB, adeE, adeY, and adeJ among the susceptible A. baumannii (SAB), multidrug-resistant A. baumannii (MDRAB), and extensively drug-resistant A. baumannii (XDRAB) groups within the 154 strains of A. baumannii. The frequencies of efflux pump genes in imipenem-susceptible and imipenem-nonsusceptible groups were significantly different for adeB, adeY, and adeJ. The frequencies of efflux pump genes in ciprofloxacin-susceptible and ciprofloxacin-nonsusceptible groups were significantly different for adeB and adeY. No significant difference was found in the frequency of efflux pump genes among groups sampled from different regions of Korea, across 86 strains of A. baumannii collected in 2012. CONCLUSIONS: The frequencies of six efflux pump genes obtained in this study demonstrate the fundamental epidemiological feature of efflux pump genes in Korean Acinetobacter clinical isolates.

Comparison of the Utility of dnaJ and 16S rDNA Sequences for Identification of Clinical Isolates of Vibrio Species

BACKGROUND: Among the many Vibrio species that can cause infections in humans, several species can cause a fatal outcome. Therefore, accurate identification of Vibrio species is very important. Since some species show atypical phenotypic features, selecting an appropriate molecular method is necessary to avoid misdiagnosis. METHODS: Vibrio clinical isolates (N=53) and reference strains (N=8) were used in this study. We analyzed the following sequences for identification: dnaJ gene, 16S rDNA, gyrase B (gyrB) V. vulnificus-specific sequence, gyrB V. navarrensis-specific sequence, and V. vulnificus hemolysin gene PCR (Vvh PCR). We performed phylogenetic analysis of the 16S rDNA, dnaJ, and gyrB sequences. Final identification was based on the combined results of all tests described above. Concordance of the 16S rDNA and dnaJ sequence analysis was measured using the Chi-square test. RESULTS: The 61 Vibrio strains were identified as follows, in descending order: V. vulnificus (78.69%), V. parahaemolyticus (6.56%), V. navarrensis (4.92%), V. mimicus (1.64%), V. cholera (1.64%), V. furnissii (1.64%), V. alginolyticus (1.64%), and Grimontia hollisae (1.64%). The accuracy rates of the dnaJ gene and 16S rDNA sequence for identification were 91.80% and 86.89%, respectively. The 16S rDNA and dnaJ sequences showed a concordance rate of 0.45, which indicates moderate agreement. CONCLUSIONS: Our results suggest that analysis of the dnaJ sequence may be a useful method for the identification of clinical isolates of Vibrio species, especially for distinguishing between closely related Vibrio species.

Primary Myelofibrosis with MPL S505N Mutation: The First Case Reported in Korea

MPL mutation is an important molecular marker in myeloproliferative neoplasms (MPN). Although MPL W515 is a hot spot for missense mutations in MPN, MPL S505 mutations have been reported in both familial and non-familial MPN. A 72-year-old male visited the hospital, complaining mainly of dizziness and epistaxis. Leukocytosis, anemia, thrombocytopenia, tear drop cells, nucleated RBCs, and myeloblasts were observed in both complete blood cell counts and peripheral blood smears. Bone marrow aspiration failed due to dilution with peripheral blood. BM biopsy indicated hypercellular marrow, megakaryocytic proliferation with atypia, and grade 3 reticulin fibrosis. Conventional cytogenetics results were as follows: 46,XY,del(13)(q12q22)[19]/46,XY[1]. Molecular studies did not detect JAK2 V617F, BCR/ABL translocation, JAK2 exon 12, and CALR exon 9 mutations. The MPL S505N mutation was verified by colony PCR and Sanger sequencing following gene cloning. Based on the above findings, a diagnosis of overt primary myelofibrosis (PMF) was indicated. Mutation studies of buccal and T cells were not conducted. Further, family members were not subjected to mutation studies. Therefore, we were unable to determine whether this mutation was familial or non-familial. Six months after the first visit to the hospital, the patient died due to pneumonia and sepsis. Thrombotic symptoms or major bleeding events did not develop during the survival period following diagnosis of PMF. To the best of our knowledge, this may be the first reported case of PMF with the MPL S505N mutation in Korea.

Assessment of Efflux Activity Using H33342 Accumulation in Tigecycline-Resistant Acinetobacter baumannii Clinical Isolates / 대한임상미생물학회지

BACKGROUND: Tigecycline resistance has emerged recently and has shown diverse mechanisms. The aim of this study was to assess the role of efflux activity in tigecycline resistance in 120 clinical isolates of A. baumannii using two methods: the H33342 accumulation assay and adeB real-time reverse transcriptase polymerase chain reaction. In addition, we analyzed the correlation between the expression level of adeB and H33342 accumulation level. METHODS: A. baumannii clinical isolates was divided into tigecycline-resistant (49 strains), intermediate (40 strains), and susceptible (31 strains) groups. The H33342 accumulation was measured in the absence or presence of the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Real-time RT-PCR was performed to determine the relative expression of the adeB gene in A. baumannii clinical isolates. RESULTS: The level of H33342 accumulation in the resistant group was relatively lower than those in the other groups. The addition of CCCP caused a significantly increased fold change in H33342 accumulation in the tigecycline-resistant group. Significant difference in the fold change level in H33342 accumulation was found between tigecycline-susceptible and resistant isolates. Those findings support the role of efflux pumps of which substrates are H33342 in the resistance of tigecycline. Significant differences in the relative expression levels of adeB were shown between tigecycline-susceptible and resistant groups also. CONCLUSION: The results showed that several efflux pumps of which substrates were H33342 can contribute to tigecycline resistance. The adeB overexpression can also contribute to tigecycline resistance. It is possible that efflux pumps other than adeB efflux pumps contribute to tigecycline resistance because there was no correlation between fold change level in H33342 accumulation and adeB expression level.

In Vitro Interactions of Antibiotic Combinations of Colistin, Tigecycline, and Doripenem Against Extensively Drug-Resistant and Multidrug-Resistant Acinetobacter baumannii

BACKGROUND: Acinetobacter baumannii infections are difficult to treat owing to the emergence of various antibiotic resistant isolates. Because treatment options are limited for multidrug-resistant (MDR) A. baumannii infection, the discovery of new therapies, including combination therapy, is required. We evaluated the synergistic activity of colistin, doripenem, and tigecycline combinations against extensively drug-resistant (XDR) A. baumannii and MDR A. baumannii. METHODS: Time-kill assays were performed for 41 XDR and 28 MDR clinical isolates of A. baumannii by using colistin, doripenem, and tigecycline combinations. Concentrations representative of clinically achievable levels (colistin 2 microg/mL, doripenem 8 microg/mL) and achievable tissue levels (tigecycline 2 microg/mL) for each antibiotic were used in this study. RESULTS: The colistin-doripenem combination displayed the highest rate of synergy (53.6%) and bactericidal activity (75.4%) in 69 clinical isolates of A. baumannii. Among them, thedoripenem-tigecycline combination showed the lowest rate of synergy (14.5%) and bacteri-cidal activity (24.6%). The doripenem-tigecycline combination showed a higher antagonistic interaction (5.8%) compared with the colistin-tigecycline (1.4%) combination. No antagonism was observed for the colistin-doripenem combination. CONCLUSIONS: The colistin-doripenem combination is supported in vitro by the high rate of synergy and bactericidal activity and lack of antagonistic reaction in XDR and MDR A. baumannii. It seems to be necessary to perform synergy tests to determine the appropri-ate combination therapy considering the antagonistic reaction found in several isolates against the doripenem-tigecycline and colistin-tigecycline combinations. These findings should be further examined in clinical studies.

Two Concurrent Chromosomal Aberrations Involving Three-way t(3;21;8)(p21;q22;q22) and Two-way t(2;11)(q31;p15) Translocations in a Case of de novo Acute Myeloid Leukemia

One of the most frequent structural chromosomal anomaly is t(8;21)(q22;q22) that occurs in approximately 5-15% of all acute myeloid leukemia (AML). However, t(3;21)(p21;q22) and t(2;11)(q31;p15) translocations are rarely reported in AML. Here, we report a unique case of AML with two translocations, t(3;21;8)(p21;q22;q22) and t(2;11)(q31;p15). Using multiplex reverse transcription polymerase chain reaction, we identified a RUNX1-RUNX1T1 fusion gene. Following a second relapse, the patient did not respond to therapy and died 55 months following the first diagnosis. We believe that this is the first case describing concurrent chromosomal aberrations involving three-way t(3;21;8) and two-way t(2;11) translocations in de novo acute myeloid leukemia.

A Novel Four-Way Translocation t(5;9;22;18)(q31;q34;q11.2;q21) in a Patient with Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) is characterized by the presence of the Philadelphia chromosome, which is generated by a reciprocal t(9;22)(q34;q11) translocation. Variant Philadelphia chromosomes, found in 5-10% of CML cases, are a result of translocations involving other chromosomes, in addition to 9 and 22. These four-way Philadelphia chromosome translocations are very rare; only about 60 patients with such chromosomes have been described. Here, we report a CML case with a novel four-way variant Philadelphia chromosome. A conventional chromosome analysis of bone marrow cells revealed a 46,XY,t(5;9;22;18)(q31;q34;q11.2;q21) karyotype, which was confirmed by multicolor fluorescence in situ hybridization. The major BCR-ABL1 fusion gene was detected by reverse transcription-nested PCR. The patient was treated with imatinib. Twelve months after treatment, he demonstrated a complete hematologic response and chromosome analysis showed that he had a normal karyotype.

A Novel Four-Way Translocation t(5;9;22;18)(q31;q34;q11.2;q21) in a Patient with Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) is characterized by the presence of the Philadelphia chromosome, which is generated by a reciprocal t(9;22)(q34;q11) translocation. Variant Philadelphia chromosomes, found in 5-10% of CML cases, are a result of translocations involving other chromosomes, in addition to 9 and 22. These four-way Philadelphia chromosome translocations are very rare; only about 60 patients with such chromosomes have been described. Here, we report a CML case with a novel four-way variant Philadelphia chromosome. A conventional chromosome analysis of bone marrow cells revealed a 46,XY,t(5;9;22;18)(q31;q34;q11.2;q21) karyotype, which was confirmed by multicolor fluorescence in situ hybridization. The major BCR-ABL1 fusion gene was detected by reverse transcription-nested PCR. The patient was treated with imatinib. Twelve months after treatment, he demonstrated a complete hematologic response and chromosome analysis showed that he had a normal karyotype.

Comparison of the Vitek 2, API 20A, and 16s rRNA Gene Sequencing for the Identification of Anaerobic Bacteria / 대한임상미생물학회지

BACKGROUND: Recently, genotypic identification of anaerobes is emerging as an alternative to the phenotypic method. In this study, we evaluated the performance of Vitek 2, API 20A and 16s rRNA gene sequencing for the identification of anaerobic bacteria. METHODS: A total of 35 anaerobe reference strains were identified using Vitek 2, API 20A and 16s rRNA gene sequencing. We evaluated the performance of three methods on the basis of the accurate identification rates. RESULTS: The Vitek 2, API 20A and 16s rRNA gene sequencing identified 54.3, 15.4, and 94.3% of test strains correctly at the species level and identified 77.1, 42.3, and 100% at the genus level, respectively. Results of the McNemar's test showed that there was a significant difference between each of the three identification methods in species level identification (P value<0.05). CONCLUSION: 16s rRNA gene sequencing showed better performance than Vitek 2 or API 20A for anaerobic bacteria. Considering its excellent performance, 16s rRNA gene sequencing may be useful for accurate identification of anaerobic bacteria that cannot be correctly identified by phenotypic methods.

Comparison of MicroScan and Phoenix Automated Systems for Detection of Extended-Spectrum beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae

The aim of this study was to evaluate the performances of MicroScan (Siemens Healthcare, USA) and Phoenix (Becton Dickinson Diagnostic Systems, USA) automated systems for the detection of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae. ESBL-producers were detected from 18 E. coli strains and 26 K. pneumoniae strains using MicroScan, Phoenix, and double-disk synergy test (DDST). The ESBL types were determined by PCR direct sequencing. ESBL genes were detected in 38 (86.4%) of the 44 test strains. The sensitivities of MicroScan, Phoenix, and DDST were 94.6%, 79%, and 89.5%, respectively. Both MicroScan and Phoenix provided acceptable results for the examination of clinical isolates.

Frequency of Extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase Genes in Escherichia coli and Klebsiella pneumoniae over a Three-year Period in a University Hospital in Korea / 대한진단검사의학회지

BACKGROUND: The aim of this study was to determine the yearly prevalence and genotype distribution of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae collected over a 3-yr period in Gwangju, Korea. METHODS: Clinical isolates of E. coli and K. pneumoniae collected at Chosun University Hospital from September 15, 2005 to September 14, 2008 were evaluated. Antimicrobial susceptibility testing was performed using the Vitek II system (bioMerieux, USA) and agar dilution methods. Screening for ESBL and AmpC beta-lactamase genes was performed using PCR amplification of plasmid DNA followed by direct sequencing of the PCR products. RESULTS: The percentage of ESBL-producing isolates was 12.6% (196/1,550) for E. coli and 26.2% (294/1,121) for K. pneumoniae. The ESBL gene sequencing results showed that the most prevalent ESBL types were CTX-M (93.5%) and SHV (12.9%) in E. coli, and SHV (73.2%) and CTX-M (46.3%) in K. pneumoniae. The most common ESBL in E. coli was CTX-M-15-like, followed by CTX-M-14-like, SHV-2a-like, and SHV-12-like. The most prevalent ESBL type in K. pneumoniae was SHV-12, followed by CTX-M-14-like and CTX-M-15-like. Fifty-one percent (21/41) of ESBL-producing K. pneumoniae with ESBL types verified by sequencing also had DHA-1-like AmpC beta-lactamases. However, none of the ESBL-producing E. coli was positive in the AmpC beta-lactamase PCR analysis. CONCLUSIONS: In this study, the most common types of class A ESBLs identified were CTX-M-15-like in E. coli and SHV-12-like in K. pneumoniae.

JAK2 V617F and Exon 12 Genetic Variations in Korean Patients with BCR/ABL1-negative Myeloproliferative Neoplasms / 대한진단검사의학회지

BACKGROUND: JAK2 genetic variations have been described in a high proportion of patients with BCR/ABL1-negative myeloproliferative neoplasms (MPN). This study was designed to analyze the frequencies of JAK2 V617F and exon 12 variations, and their correlations with clinical characteristics of Korean patients with BCR/ABL1-negative MPN. METHODS: We examined a total of 154 patients with BCR/ABL1-negative MPN that included 24, 26, 89, and 15 patients with polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET), and unclassified myeloproliferative neoplasms (MPNU), respectively. We performed allele-specific PCR to detect V617F in all BCR/ABL1-negative patients, and performed direct sequencing to detect exon 12 variations in 47 V617F-negative MPN patients. JAK2 c.1641+179_183del5 variation was detected by restriction fragment length polymorphism assay in 176 healthy subjects. RESULTS: JAK2 V617F was detected in 91 patients (59.1%): PV (91.6%), PMF (46.2%), ET (52.8%), and MPNU (66.7%). In V617F-negative MPN patients, no mutations were found in exon 12. The c.1641+179_183del5 was detected in 68.1% of V617F-negative MPN patients and 45.4% of healthy subjects (P=0.008). JAK2 V617F was closely correlated with age and leukocytosis in BCR/ABL1-negative MPN patients (P<0.05). However, c.1641+179_183del5 was not related to age, sex, or complete blood cell count parameters in V617F-negative MPN patients and healthy subjects. The c.1641+179_183del5 was associated with an increased odds ratio for MPN (odds ratio, 2.6; 95% confidences interval, 1.3-5.1; P=0.007). CONCLUSIONS: Frequencies of V617F are similar to reported results. JAK2 exon 12 mutations may be rare and c.1641+179_183del5 may influence the occurrence of MPN in Korean patients with V6 17F-negative MPN.

Annual Report on External Quality Assessment in Urinalysis in Korea (2009) / 임상검사와정도관리

Three external quality assesment trials which composed of 16 control materials(12 chemical materials and four sets of microscopic photograph of urinary sediment) for interlaboratory quality control assesment in urinalysis were performed with 796, 823, and 841 participants, in each, in the year of 2009. The response rate were 97.1% (796/820), 95.5% (823/862) and 97.1% (841/866), in the first, the second and the third trials, in each. The test items include pH, glucose, protein, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte estrase, specific gravity and four microscopic photographs of urinary sediment. The survey results are summarized as follows: 1. The chemical quality control test in urinalysis revealed generally good concordance. 2. The percentage of using urinalysis analyzer was slightly decreased as 82.3% and the distribution of using reagent strip was similar to the previous year. 3. The percentage of response rate of microscopic photographs of urinary sediment was 83.5% (702/841) and the percentage of good performance of these tests ware 83.6% to 99.1%.

Annual Report on External Quality Assessment in Urinalysis in Korea (2008) / 임상검사와정도관리

Three external quality assesment trials which composed of 16 control materials (12 chemical materials and four sets of microscopic photograph of urinary sediment) for interlaboratory quality control assesment in urinalysis were performed with 699, 718, and 732 participants, in each, in the year of 2008. The response rate were 95.4% (699/733), 96.6% (718/743) and 95.3% (732/767), in the first, the second and the third trials, in each. The test items include pH, glucose, protein, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte estrase, specific gravity and four microscopic photographs of urinary sediment. The survey results are summarized as follows: 1. The chemical quality control test in urinalysis revealed generally good concordance. 2. The percentage of using urinalysis analyzer was slightly decreased as 83.0% and the distribution of using reagent strip was similar to the previous year. 3. The percentage of response rate of microscopic photographs of urinary sediment was 81.3% (571/732) and the percentage of good performance of these tests ware 32.9% to 80.5%.

A Case of Lambda-expressing Pulmonary MALT Lymphoma with Dual Clonal Rearrangements of Kappa and Lambda Immunoglobulin Light Chain Gene / 대한진단검사의학회지

A 70-yr-old woman was hospitalized with a history of dry cough. Bronchial endoscopy and transbronchial lung biopsy were performed. However, the findings of histopathology and immunohistochemistry were not sufficient to decide whether the lesion was benign or malignant, because of the presence of crush artifacts in the biopsy specimens. We performed B-cell clonality studies using BIOMED-2 multiplex PCR (InVivoScribe Technologies, USA) to detect clonal rearrangements in the immunoglobulin gene. The results of multiplex PCR showed clonal rearrangements of both kappa and lambda immunoglobulin light chain genes. The findings of immunochemistry revealed that the lesion expressed lambda light chain, but not kappa light chain. Based on the clinical, pathologic, and molecular findings, this case was diagnosed as pulmonary MALT lymphoma. We report the first case in Korea of lambda-expressing MALT lymphoma that is shown to have dual clonal rearrangements of kappa and lambda immunoglobulin light chain gene by multiplex PCR.

Annual Report on External Quality Assessment in Urinalysis in Korea (2007) / 임상검사와정도관리

Three external quality assesment trials which composed of 16 control materials (12 chemical materials and four microscopic photographs of urinary sediment) for interlaboratory quality control assesment in urinalysis were performed with 638, 645, and 662 participants, in each, in the year of 2007. The response rate were 95.5% (638/668), 96.7% (645/667) and 97.1% (662/682), in the first, the second and the third trials, in each. The test items include pH, glucose, protein, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte esterase, specific gravity and four microscopic photographs of body fluid and urinary sediment. The survey results are summarized as follows: 1. The chemical quality control test in urinalysis revealed generally good concordance. 2. The percentage of using urinalysis analyzer was slightly increased as 87.5% and the distribution of using reagent strip was similar to the previous year. 3. The percentage of response rate of microscopic photographs of urinary sediment was 80.7% (536/662) and the percentage of good performance of these tests was 60.6% to 99.1%.

Annual Report on External Quality Assessment in Urinalysis in Korea (2007) / 임상검사와정도관리

Three external quality assesment trials which composed of 16 control materials (12 chemical materials and four microscopic photographs of urinary sediment) for interlaboratory quality control assesment in urinalysis were performed with 638, 645, and 662 participants, in each, in the year of 2007. The response rate were 95.5% (638/668), 96.7% (645/667) and 97.1% (662/682), in the first, the second and the third trials, in each. The test items include pH, glucose, protein, ketone, bilirubin, blood, urobilinogen, nitrite, leukocyte esterase, specific gravity and four microscopic photographs of body fluid and urinary sediment. The survey results are summarized as follows: 1. The chemical quality control test in urinalysis revealed generally good concordance. 2. The percentage of using urinalysis analyzer was slightly increased as 87.5% and the distribution of using reagent strip was similar to the previous year. 3. The percentage of response rate of microscopic photographs of urinary sediment was 80.7% (536/662) and the percentage of good performance of these tests was 60.6% to 99.1%.

Epidemiological Investigation of an Outbreak of Escherichia coli Infections in Neonatal Intensive Care Unit of a University Hospital / 대한임상미생물학회지

BACKGROUND: In July 2007, three neonates in the neonatal intensive care unit (NICU) of Chosun University Hospital expired due to Escherichia coli sepsis. An E. coli outbreak was suspected. METHODS: To investigate the outbreak, environmental cultures were taken from NICU. We performed repetitive extragenic palindromic (rep)-PCR to compare genotypes of the three isolates from the cases and one environmental strain of E. coli. A case-control study was done in order to identify risk factors for the infection. RESULTS: In July 2007, the attack rate of E. coli was 11.1%, which was higher than the basal rate. All the three E. coli isolates from the cases presented the same antimicrobial susceptibility pattern whereas other E. coli isolated from non-outbreak period presented different patterns. Among environmental cultures, only one specimen collected from the surface of a bathtub for neonates was culture positive for E. coli. Three strains of the cases and one environmental strain of E. coli showed the same rep-PCR pattern, while control strains showed different patterns. No statistically significant difference in risk factors was found between the case and control groups in the case-control study. CONCLUSION: The result of rep-PCR assay showed that the outbreak had originated from a single clone of E. coli. But we could not identify risk factors for the infection. The attack rate of E. coli in NICU returned to the basal level after implement of the infection control measures such as disinfection of NICU environment and equipments, thorough hand washing, and education of health care workers.

A Strain of Nocardia cyriacigeorgica Isolated from a Patient with Pulmonary Infection / 대한임상미생물학회지

Nocardia cyriacigeorgica is an aerobic gram-positive rod that has mostly been reported as an opportunistic pathogen. Since molecular methodologies were introduced to identify species, infections caused by N. cyriacigeorgica have been reported. The patient was a 51-year-old woman with aplastic anemia, systemic lupus erythematosus, and disseminated tuberculosis, who was admitted to Chosun University Hospital with a history of fever and productive cough. During her hospitalization, sputum cultures were taken and a bacterium suspicious of acitinomycetes grew five times. It was a gram-positive rod that was also partially acid-fast on modified Kinyoun stain and resistant to lysozyme. After 24 h of incubation, cultures of the sputum onto sheep's blood agar plates (BAP) demonstrated rough, chalky, and white colonies with a characteristic earthy odor. Based on the above results, the presumptive identification of Nocardia species was made. To identify species of this isolate, 16S rRNA gene sequence analysis was taken and showed 99.9% homology to N. cyriacigeorgica DSM44484(T). The results of biochemical tests were compatible with other reports of N. cyriacigeorgica. As a result, this isolate was identified as N. cyriacigeorgica. Herein, we present a first report of N. cyriacigeorgica isolated from a patient with pulmonary infection in Korea.

Evaluation of Infrequent-Restriction-Site PCR for Epidemiological Typing of Candida tropicalis / 대한임상미생물학회지

BACKGROUND: We evaluated the usefulness of a newly developed molecular typing method of infrequent restriction site polymerase chain reaction (IRS-PCR) as an epidemiological DNA fingerprinting tool for Candida tropicalis. METHODS: Thirty-two strains of C. tropicalis comprising eight sporadic strains and 24 clonal strains belonging to six clones, of which clonal type were previously confirmed by pulsed-field gel electrophoresis (PFGE), were tested by IRS-PCR to evaluate the usefulness of this technique. Twenty strains of Candida species, including C. glabrata, C. krusei, C. albicans, and C. parapsilosis, were also tested to assess the ability of IRS-PCR to discriminate among species of Candida. RESULTS: Using the IRS-PCR assay, sporadic strains of C. tropicalis could not be differentiated from clonal strains. Most strains belonging to the same clones were classified as different IRS-PCR types or clusters, and some different sporadic strains were classified as the same IRS-PCR types. When pattern variation was examined for different strains of C. tropicalis using IRS-PCR, pairwise similarity measured by the Dice coefficient was 75.4~100%. In contrast, pairwise similarity among isolates of five different species of Candida was 25~69.2%. Therefore, five different species of Candida were easily differentiated. CONCLUSION: The IRS-PCR typing assay appears to be an inadequate tool for the epidemiological typing of C. tropicalis, because the typing result of IRSPCR is not comparable to that of PFGE. To our knowledge, this is the first evaluation study for IRSPCR as an epidemiological typing tool for C. tropicalis.