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The original version of this article contained errors in the description of novel species. These errors are corrected with this corrigendum.

Objectives To investigate the risk factors of patients with Klebsiella pneumoniae (KP) bloodstream infection (BSI) with a focus on antimicrobial resistance and virulence factors. Methods All KP BSI patients (n = 579) from six general hospitals during a 1 year period were included in this study. The risk factors of hosts and causative KP isolates were assessed to determine associations with the 30 day mortality of KP BSI patients by multivariate Cox hazards modelling. Results The 30 day mortality rate of KP BSI patients was 16.9% (98/579). Among the host-associated factors, increased SOFA score and leucopenia status exhibited strong associations with increased 30 day mortality. Among the pathogenic factors, carriage of the pks gene cluster (adjusted HR 1.80; 95% CI 1.16-2.79) was a risk factor, especially when accompanied by MDR. In this regard, KP isolates of the wzi50 capsular type (n = 22) frequently harboured pks (63.6%, 14/22) and ybtA (68.2%, n = 15) and mostly exhibited MDR (63.6%, n = 14), resulting in increased 30 day mortality. In contrast, hypermucoviscous KP isolates showed an inverse association with 30 day mortality (adjusted HR 0.55; 95% CI 0.33-0.90). Conclusions Despite the reported virulence of hypermucoviscous KP strains, they were associated with good prognoses in KP BSI patients. Importantly, carriage of the pks gene cluster, which is responsible for the synthesis of colibactin, was a relevant marker of early mortality.

In the present study, three strains (ChDC F213T, ChDC F251, and ChDC F267) were classified as novel species of genus Fusobacterium based on average nucleotide identity (ANI) and genome-to-genome distance (GGD) analysis and chemotaxonomic characterization. 16S rDNA sequences of strains ChDC F213T, ChDC F251, and ChDC F267 were highly similar to that of F. periodonticum ATCC 33693T (99.6, 99.4, and 99.4%, respectively). ANI and GGD values of the three isolates with F. periodonticum ATCC 33693T ranged from 92.5 to 92.6% and 47.7 to 48.2%, respectively. Considering that threshold of ANI and GGD values for bacterial species discrimination are 95-96% and 70%, respectively, these results indicate that the three isolates represent a novel Fusobacterium species. DNA G + C contents of the three isolates were 28.0 mol% each. Cellular fatty acid analysis of these strains revealed that C14:0, C16:0, and C16:1 ω6c/C16:1 ω7c were major fatty acids. Therefore, these three strains are novel species belonging to genus Fusobacterium. Strain ChDC F213T (= KCOM 1259T = KCTC 5677T = JCM 33009T) is the type strain of a novel species of genus Fusobacterium, for which a name of Fusobacterium pseudoperiodonticum sp. nov. is proposed.

A total of 281 nonduplicated Staphylococcus aureus blood isolates were collected from January to May 2017 from eight hospitals in South Korea to investigate the epidemiological traits of ceftaroline resistance in methicillin-resistant S. aureus (MRSA). Cefoxitin-disk diffusion tests and the mecA gene PCR revealed that 56.6% (159/281) of the S. aureus isolates were MRSA, and most belonged to ST5 (50.3%, 80/281) and ST72 (41.5%, 66/281). Of the MRSA isolates, 44.0% (70/159) were nonsusceptible to ceftaroline (MIC ≥ 2 mg/liter), whereas all of the methicillin-susceptible S. aureus isolates were susceptible to the drug. Eight amino acid substitutions in penicillin-binding protein 2a (PBP2a), including four (L357I, E447K, I563T, and S649A) in the penicillin-binding domain (PBD) and four (N104K, V117I, N146K, and A228V) in the non-PBD (nPBD) of PBP2a, were associated with ceftaroline resistance. The accumulation of substitutions in PBP2a resulted in the elevation of ceftaroline MICs: one substitution at 1 to 2 mg/liter, two or three substitutions at 2 to 4 mg/liter, and five substitutions at 4 or 16 mg/liter. Ceftaroline resistance in MRSA might be the result of clone-specific PBP2a polymorphism, along with substitutions both in PBD and nPBD, and the elevated ceftaroline MICs were associated with the substitution sites and accumulation of substitutions.

The Korean government established an antimicrobial resistance (AMR) surveillance system, compatible with the Global AMR Surveillance System (GLASS): Kor-GLASS. We describe results from the first year of operation of the Kor-GLASS from May 2016 to April 2017, comprising all non-duplicated clinical isolates of major pathogens from blood, urine, faeces and urethral and cervical swabs from six sentinel hospitals. Antimicrobial susceptibility tests were carried out by disk diffusion, Etest, broth microdilution and agar dilution methods. Among 67,803 blood cultures, 3,523 target pathogens were recovered. The predominant bacterial species were Escherichia coli (n = 1,536), Klebsiella pneumoniae (n = 597) and Staphylococcus aureus (n = 584). From 57,477 urine cultures, 6,394 E. coli and 1,097 K. pneumoniae were recovered. Bloodstream infections in inpatients per 10,000 patient-days (10TPD) were highest for cefotaxime-resistant E. coli with 2.1, followed by 1.6 for meticillin-resistant Sta. aureus, 1.1 for imipenem-resistant Acinetobacter baumannii, 0.8 for cefotaxime-resistant K. pneumoniae and 0.4 for vancomycin-resistant Enterococcus faecium. Urinary tract infections in inpatients were 7.7 and 2.1 per 10TPD for cefotaxime-resistant E. coli and K. pneumoniae, respectively. Kor-GLASS generated well-curated surveillance data devoid of collection bias or isolate duplication. A bacterial bank and a database for the collections are under development.

Surveillance plays a pivotal role in overcoming antimicrobial resistance (AMR) in bacterial pathogens, and a variety of surveillance systems have been set up and employed in many countries. In 2015, the World Health Organization launched the Global Antimicrobial Resistance Surveillance System (GLASS) as a part of the global action plan to enhance national and global surveillance and research. The aims of GLASS are to foster development of national surveillance systems and to enable collection, analysis and sharing of standardised, comparable and validated data on AMR between different countries. The South Korean AMR surveillance system, Kor-GLASS, is compatible with the GLASS platform and was established in 2016 and based on the principles of representativeness, specialisation, harmonisation and localisation. In this report, we summarise principles and processes in order to share our experiences with other countries planning to establish a national AMR surveillance system. The pilot operation of Kor-GLASS allowed us to understand the national burden of specific infectious diseases and the status of bacterial AMR. Issues pertaining to high costs and labour-intensive operation were raised during the pilot, and improvements are being made.

Nucleic acid extraction is the first step of any amplification experiment no matter what kind of amplification is used to detect a specific pathogen. Efficient nucleic acid extraction is essential to obtain good results using any molecular test. The optimal extraction method should fulfill the following conditions: speed, short working time, cost-effectiveness, high sensitivity and specificity, good reproducibility, and safety. The methods can be divided into solution or column based according to differences of their principles. The automated extraction instruments have many advantages, and these have proven to be very useful. Moreover, in recent years, fully automated instruments combining NA extraction and amplification have been commercially available. However, the method itself does not provide assurance, and the DNA recovery can be different among various kits or instruments that use the similar principles. Therefore, it is important to carefully evaluate the performance of any extraction method used in the clinical microbiology laboratory even though manufacturers may have reported good validation results with specific organisms.

Background Antibiotic resistance is a significant threat to public health not only in healthcare setting but also in community because antimicrobial-resistant infections can be transmitted in community. Although it is essential to know whether there are particular reasons that caused antibiotic-resistant infection in community, there is lack of evidence regarding risk factors for community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae bloodstream infection (ESBL-KP BSI) in South Korea. In the present study, we aimed to reveal risk factors for community-onset ESBL-KP BSI. Methods From May 2016 to April 2017, patients with community-onset KP BSI (n = 408) from six sentinel hospitals in South Korea were included. The hospitals are located in different districts throughout South Korea, and had a total of 5,194 beds, ranged from 715 to 1,050 beds per hospital. Admission history and previous usage of antibiotics and medical devices before bacteremia were acquired from National Health Insurance claims data. Risk factors of ESBL-KP BSI were analyzed with a multivariable logistic regression model. PCR and sequencing for the identification of genes encoding ESBLs, and multilocus sequence typing were performed. Results Of 408 patient of community-onset KP BSI, 70 (17%) were ESBL-KP BSI patients. ESBL-KP isolates most frequently carried CTX-M-1-group ESBLs (74%, n = 52), followed by CTX-M-9-group ESBLs (16%, n = 11). Most prevalent sequence type (ST) among ESBL-KP isolates was ST48 (14%, n = 10). Among non-ESBL-KP isolates, ST23 was most prevalent (21%, n = 70). Analyzing with multivariate analysis, recent admission to long-term care hospital within 3 months (OR, 5.7; 95% CI, 2.1–15.6; P = 0.001), previous usage of trimethoprim-sulfamethoxazole (OR, 11.5; 95% CI, 2.7–48.6; P = 0.001), expanded-spectrum cephalosporin (OR, 2.2; 95% CI, 1.2–3.9; P = 0.01), and previous use of urinary catheter (OR, 2.3; 95% CI, 1.1–4.5; P = 0.02) were identified as independent risk factors for community-onset ESBL-KP BSI. Conclusion Recent admission to long-term care hospital, use of urinary catheter, recent usage of antibiotics were identified as risk factors for community-onset ESBL-KP BSI. Strict antibiotic stewardship and infection control measures in long-term care hospital are needed. Disclosures All authors: No reported disclosures.

The aim of this study was to evaluate the diagnostic accuracy of the GenoType MTBDRplus assay in detecting drug-resistant tuberculosis (DR-TB) by using acid-fast bacilli (AFB) smear-negative specimens with positive TB-PCR results.The MTBDRplus assay was performed with 2 different categories of 117 samples, including AFB smear-positive specimens (n = 53) and AFB smear-negative specimens (n =64), which exhibited positive TB-PCR results, at a single institution. The results were retrospectively compared with the results of the phenotypic drug susceptibility test (DST), for reference.A total of 105 tests were finally analyzed. Of these, 54 tests were conducted using AFB smear-negative specimens with positive TB-PCR results. The MTBDRplus assay for these 54 samples demonstrated a sensitivity of 100%, specificity of 98%, positive predictive value (PPV) of 75%, and negative predictive value (NPV) of 100% in detecting rifampicin resistance. With these same species, the sensitivity, specificity, PPV, and NPV values for the MTBDRplus assay were 83.3%, 97.9%, 83.3%, and 97.9%, respectively, for the detection of isoniazid resistance. The overall correlation between the MTBDRplus assay and phenotypic DST demonstrated excellent agreement for detection of rifampicin resistance (κ = 0.847) and for detection of INH resistance (κ = 0.812), respectively.The MTBDRplus assay can be used effectively even on AFB smear-negative specimens from TB patients, when the TB-PCR is positive. This result might help clinicians to manage patients with suspected DR-TB in difficult situations.

The release of extracellular vesicles, also known as outer membrane vesicles, membrane vesicles, exosomes, and microvesicles, is an evolutionarily conserved phenomenon from bacteria to eukaryotes. It has been reported that Mycobacterium tuberculosis releases extracellular vesicles harboring immunologically active molecules, and these extracellular vesicles have been suggested to be applicable in vaccine development and biomarker discovery. However, the comprehensive proteomic analysis has not been performed for M. tuberculosis extracellular vesicles. In this study, we identified a total of 287 vesicular proteins by four LC-MS/MS analyses with high confidence. In addition, we identified several vesicular proteins associated with the virulence of M. tuberculosis. This comprehensive proteome profile will help elucidate the pathogenic mechanism of M. tuberculosis. The data have been deposited to the ProteomeXchange with identifier PXD001160 (http://proteomecentral.proteomexchange.org/dataset/PXD001160).

Purpose. A new automated Cobas u 701 microscopy analyser for urine sediment examination was introduced. The aim of this study was to evaluate the analyser in comparison with urine culture in screening for urinary tract infection (UTI). Methodology. A total of 852 urine specimens submitted for culture were included in this study. Urine sediment examination was performed using the Cobas u 701 microscopy analyser. The results of the bacteria (BAC) and yeast (YEA) analyses were compared with the results from urine culture as a method for UTI screening. In addition, we compared the BAC results with white blood cells (WBCs) and leukocyte and nitrite measurement in the Cobas u 601 system. Results. Of the 852 urine specimens, 16.1 % (N=137) were positive by urine culture, yielding 130 bacteria from 124 specimens and 14 yeasts from 14 specimens. The Cobas u 701 microscopy analyser provided no result for 52 specimens because of their high turbidity. The sensitivity, specificity, positive predictive value and negative predictive value were 85.8, 69.4, 33.1 and 96.5 %, respectively. For YEA, these figures were 100, 91.9, 15.8 and 100 %, respectively. The areas under the curve for BAC and WBCs were 0.827 [95 % confidence interval (CI) 0.799, 0.852] and 0.727 (95 % CI 0.695, 0.757), respectively. The sensitivity of the leukocyte and nitrite was 63.5 and 54.6 %, respectively. Conclusion. The Cobas u 701 microscopy analyser showed good diagnostic performance. It can be used for rapid screening for UTI and can reduce the number of cultures required.

Background The isolation of nontuberculous mycobacteria (NTM) from clinical specimens has increased, and they now are considered significant opportunistic pathogens. The aims of this study were to develop a database and interpretive criteria for identifying individual species. In addition, using clinical isolates, we evaluated the clinical usefulness of 16S rRNA, hsp65, and rpoB as target genes for this method. Methods The sequences of NTM for 16S rRNA, hsp65, and rpoB were collected from GenBank and checked by manual inspection. Clinical isolates collected between 2005 and 2010 were used for DNA extraction, polymerase chain reaction, and sequencing of these three genes. We constructed a database for the genes and evaluated the clinical utility of multilocus sequence analysis (MLSA) using 109 clinical isolates. Results A total 131, 130, and 122 sequences were collected from GenBank for 16S rRNA, hsp65, and rpoB, respectively. The percent similarities of the three genes ranged from 96.57% to 100% for the 16S rRNA gene, 89.27% to 100% for hsp65, and 92.71% to 100% for rpoB. When we compared the sequences of 109 clinical strains with those of the database, the rates of species-level identification were 71.3%, 86.79%, and 81.55% with 16S rRNA, hsp65, and rpoB, respectively. We could identify 97.25% of the isolates to the species level when we used MLSA. Conclusion There were significant differences among the utilities of the three genes for species identification. The MLSA technique would be helpful for identification of NTM.

Group B streptococcus (GBS) is one of the leading causes of invasive infections in infants. This study aimed to investigate the genotypic diversity of GBS causing invasive infections in infants and to observe the prevalence of the highly virulent clone in South Korea.Invasive strains of GBS were collected prospectively from infants admitted at 4 hospitals during 1995-2015. Serotype and multilocus sequence typing were determined. All isolates underwent polymerase chain reaction amplification to detect the presence of the hypervirulent GBS adhesin (hvgA) gene. Antibiotic susceptibility testing was done by E-test, and erythromycin resistance genes were detected using polymerase chain reaction amplification.Among 98 GBS isolates collected, 14 sequence types (STs) were found; ST1 (20.4%), ST17 (19.4%) and ST19 (18.4%) were the most prevalent. The dominant serotype capsule expressed by ST1 was serotype V, ST17 and ST19 were all serotype III and ST23 was serotype Ia. hvgA gene was detected in 19.4% (n = 19) of the isolates; all were ST17, serotype III. A significant temporal trend of serotype III isolates was observed; as ST17 increased (P = 0.001) in proportion, ST19 decreased (P = 0.009). Erythromycin resistance was found in 42.9% (42/98); dominant strains were ermB-positive ST1 serotype V (n = 18/20, 90%), ermB-positive ST17 serotype III (n = 10/19, 52.6%) and ermA-positive ST335 serotype III (n = 7/7, 100%).The predominant STs causing invasive infections in South Korea were ST1, ST19 and ST17. Among serotype III isolates, an increase in proportion of the hypervirulent ST17 strains was observed. Erythromycin resistance was significantly associated with ST1.

Clostridium difficile is one of the main etiological agents causing antibiotic-associated diarrhea. This study investigated the genetic diversity of 70 toxigenic C. difficile isolates from two Korean hospitals by employing toxinotyping, ribotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). Toxin gene amplification resulted in 68 A(+)B(+) and two A(-)B(+) isolates. Most isolates (95.7-100%) were susceptible to daptomycin, metronidazole, and vancomycin. Seventy C. difficile isolates were classified into five toxinotypes, 19 ribotypes, 16 sequence types (STs), and 33 arbitrary pulsotypes. All C. difficile isolates of ribotype 018 (n = 38) were classified into ST17, which was the most prevalent ST in both hospitals. However, C. difficile isolates of ST17 (ribotype 018) exhibited pulsotypes that differed by hospital. ST2 (ribotype 014/020), 8 (ribotypes 002), 17 (ribotype 018), and 35 (ribotypes 015) were detected in both hospitals, whereas other STs were unique to each hospital. Statistical comparison of the different typing methods revealed that ribotyping and PFGE were highly predictive of STs. In conclusion, our epidemiological study indicates that C. difficile infections in both hospitals are associated with the persistence of endemic clones coupled with the emergence of many unique clones. A combination of MLST with PFGE or ribotyping could be useful for monitoring epidemic C. difficile strains and the emergence of new clones in hospitals.

Peritonitis is a potentially serious complication in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). More than 50% of positive cultures from these infections are due to gram-positive bacteria, most commonly coagulase-negative staphylococci and Staphylococcus aureus [1]. Fungal peritonitis accounts for only 3-6% of cases, in which peritoneal dialysis complications are reported [2]. Peritonitis resulting from fungal infection is associated with a longer duration of illness and greater frequencies of hospitalization, high morbidity and mortality rates ranging 20-30% [2], and permanent hemodialysis compared with cases of non-fungal peritonitis [3]. The most common cause of the disease is yeast, with Candida species accounting for 70-90% of infections in adults [2]. We report the first case of CAPD-related peritonitis caused by Cryptococcus arboriformis, an organism never previously been reported as a human pathogen and confirmed by ribosomal DNA gene sequencing. A 58-yr-old man was admitted complaining of turbid peritoneal dialysis effluent. The patient presented with diabetes mellitus, hypertension, and end-stage renal disease and had been undergoing CAPD for 10 months. He was a heavy drinker, living alone in low socioeconomic conditions, and had not been properly maintaining the cleanliness of his catheter. He had experienced previous episodes of peritonitis, the last occurring 1 month earlier, at which time he was admitted to our hospital. Initially, he was given cefazolin and ceftazidime, administered intraperitoneally, which had no effect. Culture results revealed Aeromonas hydrophila, and the patient was treated with imipenem for 2 weeks, which effectively reduced the white blood cell (WBC) count (8×106 cells/L in peritoneal fluid). He was discharged after 19 days with no symptoms and with a clear dialysate. On follow-up a week later, the patient again complained of continuous abdominal pain and turbid dialysis effluent. On physical examination, he was febrile, with a healthy catheter exit site. The peritoneal fluid was straw colored and cloudy with WBC count of 1.3×109/L, of which 98% were polymorphonuclear cells and 2% were lymphocytes, confirming peritonitis. Hemoglobin concentration was 7.6 g/dL, WBC count was 9.7×109/L, and platelet count was 339×109/L. Erythrocyte sedimentation rate was 83 mm/hr, C-reactive protein concentration was 1.63 mg/dL, and blood urea nitrogen and creatinine concentrations were 62.2 mg/dL and 8.6 mg/dL, respectively. The patient was initially treated with cefazolin and ceftazidime, administered intraperitoneally, which produced no clinical improvement. A few days later, culture of the peritoneal fluid revealed an unidentified yeast species, which was also seen on Gram staining of the peritoneal fluid. The patient was readmitted, and oral administration of fluconazole (200 mg/day) was initiated for empirical treatment of CAPD fungal peritonitis. The drug was administered from days 2 to 8. The catheter in his abdomen was removed on day 6, and he was switched to hemodialysis with placement of an appropriate catheter. Despite treatment with antifungal medication and removal of the peritoneal catheter, the patient continued to experience mild fever and abdominal pain, and yeast was again found in the peritoneal fluid culture. Treatment was switched to intravenous amphotericin B (0.5 mg/kg of body weight/day) for 4 weeks, which produced no adverse effects, such as hypersensitivity reactions, and resulted in an improvement of the clinical prognosis. Oral fluconazole (400 mg/day) was administrated for 3 weeks, and the patient was discharged without any symptoms. A species of yeast was isolated from peritoneal fluid after culturing the fluid for 48 hr at 35℃ in 5% CO2 on blood agar and chocolate agar plates. The 2- to 3-mm sized colonies that grew on the agar were smooth and white. A wet smear of the peritoneal fluid revealed yeast (Fig. 1), but the isolate was not identified by Vitek 2 YST system (bioMerieux, St. Louis, MO, USA). We performed sequencing of the internal transcribed spacer 1 (ITS1) regions and D1/D2 region of the 28S ribosomal DNA gene; analysis showed 99% homology with Cryptococcus arboriformis ITS1 (GenBank accession no. AB260936) and 100% homology with Cryptococcus arboriformis D1/D2 (Fig. 2). This isolate was ultimately confirmed as Cryptococcus arboriformis through sequence analysis of the 28S ribosomal DNA gene. We performed antifungal susceptibility testing with Vitek 2 AST-YS01 system (bioMerieux). The minimum inhibitory concentrations were 0.5 µg/mL of amphotericin B, ≤1 µg/mL of fluconazole, and 8 µg/mL of flucytosine. Fig. 1 Saline mount of peritoneal dialysate showing budding yeast growing on blood agar plate for 48 hr at 35℃ (×1,000). Fig. 2 Phylogenetic trees using neighbor-joining analysis of (A) the internal transcribed spacer 1 (ITS1) regions and (B) the D1/D2 region of the ribosomal DNA gene of Cryptococcus arboriformis (GenBank accession no. AB260936) and the strain EMC 2010-8. Fungal peritonitis is a severe form of peritonitis that usually occurs after a course of antibiotics prescribed to treat bacterial peritonitis [4]. Predisposing risk factors may include prolonged use of antibiotics, previous bacterial peritonitis, immunosuppression, bowel perforation, malnutrition, and diverticulitis [2]. The effects of comorbid diseases, such as diabetes and cancer, are controversial, and duration of dialysis, age, and sex do not seem to have significant associations with the condition [5, 6]. The present patient had experienced previous bacterial peritonitis, which was treated using broad spectrum antibiotics, including imipenem. His heavy drinking, low socioeconomic status, and unclean catheter may also have predisposed him to the infection [3]. Cryptococcal peritonitis complicating CAPD is rarely reported [7]. A PubMed search, performed by using a combination of the criteria "Cryptococcus," "cryptococcosis," or "cryptococcal" with "peritonitis", produced a list of only 45 cases in the literature, occurring between 1973 and 2011. All but 2 of the isolates were identified as Cryptococcus neoformans, the exceptions being 2 cases of Cryptococcus laurentii [8, 9]. Cryptococcus arboriformis, a basidiomycetous yeast species, was recently isolated from the urine of a Japanese patient with chronic renal failure [10]. It is closely related to Cryptococcus haglerorum and is classified under the Trichosporonales lineage [10]. We were not able to identify our isolate using conventional yeast identification tests because this newly identified species are not yet in the NCBI database (a genome database of the National Center for Biotechnology Information). We identified this strain as Cryptococcus arboriformis on the basis of phylogenetic analysis by sequencing the ITS1 regions and the D1/D2 region of the 28S ribosomal DNA gene. Previous reported cases of cryptococcal peritonitis associated with CAPD were usually treated with a 2- to 3-month course of antifungal agents and removal of the dialysis catheter [7]. In this case, when the disease was confirmed to be the result of infection by an unidentified yeast species, we suspected a Candida infection, as this organism is the most common pathogen in fungal peritonitis and consequently, we initially treated the patient with fluconazole. Cryptococcus arboriformis was identified after the therapy was changed to amphotericin B. Removal of the catheter was recommended to the patient on day 6, immediately following identification of fungi and continuous administration of antifungal agents for an additional 10 days [11]. A recent study supports catheter removal within 24 hr after the diagnosis of fungal peritonitis [12]. In this case, fluconazole therapy produced no clinical improvement; therefore, the catheter was removed and hemodialysis was begun while continuing the antifungal treatment. Recently, new triazole compounds such as voriconazole and posaconazole have been tested [2]. In a retrospective study, a triazole-flucytosine combination appeared to be as effective as amphotericin B [13]. Echinocandins, such as caspofungin, micafungin, and anidulafungin, are also providing new treatment options for fungal peritonitis, but they are not effective against infections caused by basidiomycetes, such as Cryptococcus [2, 14]. There is a report that ciprofloxacin may be useful as an adjunctive agent in the treatment of cryptococcal peritonitis [15]. In this case, susceptibility testing for some antifungal agents was carried out. The isolate was susceptible to amphotericin B and fluconazole with intermediate sensitivity to flucytosine. As there were no interpretive minimum inhibitory concentration breakpoints available for the isolate, we used the guidelines for Cryptococcus neoformans. Identifying more antifungal agents and establishing a standard for susceptibility tests would be valuable for the treatment of Cryptococcus arboriformis in the future. Identification of Cryptococcus arboriformis and susceptibility testing were performed after the initial antifungal therapy had been administered. Efficient diagnosis of fungal peritonitis is crucial, if biological or clinical abnormalities continue following treatment for bacterial peritonitis, especially in patients with a history of prolonged use of antibiotics or previous bacterial peritonitis. When an unidentified organism is suspected of causing a disease and conventional identifying methods fail, identification of the pathogen using sequencing and testing the sensitivity of the organism to known antimicrobial agents may lead to an early diagnosis and a better prognosis for patients. In summary, we describe a case of cryptococcal peritonitis in a patient undergoing CAPD. To the best of our knowledge, this is the first reported case of peritonitis caused by Cryptococcus arboriformis.

Miliary tuberculosis (TB) is a rare extrapulmonary form of TB, and there have been only two reports of miliary TB associated with infection with multidrug-resistant (MDR)-TB pathogen in an immunocompetent host. A 32-year-old woman was referred to our hospital because of abnormal findings on chest X-ray. The patient was diagnosed with MDR-TB by a line probe assay and was administered proper antituberculous drugs. After eight weeks, a solid-media drug sensitivity test revealed that the pathogen was resistant to ethambutol and streptomycin in addition to isoniazid and rifampicin. The patient was then treated with effective antituberculous drugs without delay after diagnosis of MDR-TB. To the best of our knowledge, this is the first case of miliary TB caused by MDR-TB pathogen in Korea.

Introduction. The aim of this study was to differentiate betweenCandida famataandCandida guilliermondiicorrectly by using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) and gene sequencing.Methods. Twenty-eightCandidastrains from blood cultures that had been identified asC. famata(N=25),C. famata/C. guilliermondii(N=2), andC. guilliermondii(N=1) by the VITEK 2 system using the YST ID card were included. We identified these strains by MALDI-TOF MS and gene sequencing using the 28S rRNA andITSgenes and compared the results with those obtained by the VITEK 2 system.Results. All 28 isolates were finally identified asC. guilliermondii.Sequencing analysis of the 28S rRNA gene showed 99.80%–100% similarity withC. guilliermondiifor all 28 strains. TheITSgene sequencing of the strains showed 98.34%–100% homology withC. guilliermondii.By MALDI-TOF, we could correctly identify 21 (75%) of 28C. guilliermondiiisolates.Conclusion. We should suspect misidentification whenC. famatais reported by the VITEK 2 system, and we always should keep in mind the possibility of misidentification of any organism when an uncommon species is reported.

The molecular epidemiology and antimicrobial resistance of Clostridioides difficile were studied in South Korea in 2017 as part of a National Surveillance System. From February to May 2017, all non-duplicate isolates of C. difficile were recovered from patients who were suspected to have C. difficile infection and collected from 6 referral hospitals representing the 6 regions in South Korea. We performed PCRs for the toxin gene, PCR ribotyping, multilocus sequence typing (MLST), antimicrobial susceptibility testing by agar dilution according to the recommendations of the CLSI and detection of antimicrobial resistance genes such as ermB, catD, tetM, vanZ and nimR by PCR. Of 331 C. difficile isolates, 257 (77.6%) were toxigenic and the prevalence of strains producing binary toxin (CDT) was 5.1% (13/257). A total of 52 different ribotype (RT) patterns were found. RT018 was the most common (25.1% of all isolates), and RT014/020, RT002 and RT012 were also common. RT010 was most common non-toxigenic strain. MLST analysis of randomly selected 72 C. difficile isolates identified 46 sequence types (STs), of which three were new and not in the PubMLST library. There was a good correlation between MLST and RT as following: ST1 (RT027), ST8 (RT002), ST11 (RT078), ST17 (RT018), ST35 (RT046), ST37 (RT017), ST42 (RT106), ST53 (RT103), ST81 (RT369), and ST99 (RT070). All toxigenic isolates were susceptible to metronidazole and vancomycin (MIC ≤ 2 mg/L). For rifaximin, 24% of toxigenic isolates were resistant. Of randomly selected 106 toxigenic isolates, resistance rates for ampicillin, cefotetan, clindamycin, imipenem, chloramphenicol, tetracycline, and moxifloxacin were 48%, 46%, 64%, 54%, 0%, 6% and 52% respectively and frequencies of various resistance genes were 62.3% for ermB, 0.9% catD and 10.4% tetM. RTs018, 002, 017 and 369 showed high MICs to various antimicrobial agents and multi-drug resistance was common also.

Background: The isolation of carbapenemase-producing Enterobacteriaceae (CPE) has become increasingly common. Continuous surveillance for these organisms is essential because their infections are closely related to outbreaks of illness and are associated with high mortality rates. The aim of this study was to develop and evaluate multiplex PCR as a means of detecting several important CPE genes simultaneously.Methods: We aimed to develop a multiplex PCR that could detect seven CPE genes simultaneously. The multiplex PCR was composed of seven primer sets for the detection of KPC, IMP, VIM, NDM-1, GES, OXA-23, and OXA-48. We designed different PCR product sizes of at least 100 bp. We evaluated the performance of this new test using 69 CPE-positive clinical isolates. Also, we confirmed the specificity to rule out false-positive reactions by using 71 carbapenem- susceptible clinical strains.Results: A total of 69 CPE clinical isolates showed positive results and were correctly identified as KPC (N=14), IMP (N=13), OXA-23 (N=12), OXA-48 (N=11), VIM (N=9), GES (N=5), and NDM (N=5) by the multiplex PCR. All 71 carbapenem-susceptible clinical isolates, including Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, showed negative results.Conclusion: This multiplex PCR can detect seven CPE genes at a time and will be useful in clinical laboratories. (Ann Clin Microbiol 2019;22:9-13)

Primary extranodal natural killer (NK)/T-cell lymphoma (NTCL) of the gastrointestinal tract is extremely rare. It has an aggressive clinical course with a high mortality rate; early diagnosis is usually difficult because patients show nonspecific symptoms. We describe a case of primary NTCL of the small intestine in a 45-year-old ethnic Korean woman who has clinical features similar to those of inflammatory bowel disease (IBD). Laparotomy revealed a perforated jejunum and numerous masses in the mesentery. NTCL was diagnosed by a pathologist based on the results of immunohistochemical staining and the detection of Epstein-Barr virus–encoded messenger RNA (mRNA) via in situ hybridization. On examination, a bone marrow sample showed diffuse histiocytic proliferation with hemophagocytosis. Although the patient received dose-intense chemotherapy and supportive treatment, she died 21 days after her diagnosis. Herein, we report a rare case of primary NTCL of the small intestine with reactive hemophagocytic syndrome and review the literature on this rare disease.

As pulmonary fungal infections continue to increase due to an increasing number of immunocompromised patients, rapid detection and accurate identification of these fungal pathogens are critical. A broad fungal assay was developed by incorporating broad-range multilocus PCR amplification and electrospray ionization/mass spectrometry (PCR/ESI-MS) to detect and identify fungal organisms directly from clinical specimens. The aims of this study were to evaluate the performance of PCR/ESI-MS for detection, identification, and determination of the distribution of fungal organisms in bronchoalveolar lavage (BAL) fluid specimens. The BAL fluid specimens submitted for fungal culture at Vanderbilt University Medical Center between May 2005 and October 2011 were included. Cultures and identification were done using standard procedures. In addition, DNA was extracted from BAL fluid specimens, and fungal DNA amplification/identification were performed by PCR/ESI-MS. The results were compared with those of the standard cultures. A total of 691 nonduplicated BAL fluid specimens with sufficient leftover volume for molecular testing were evaluated using PCR/ESI-MS. Among them, 134 specimens (19.4%) were positive for fungi by both culture and PCR/ESI-MS testing. Of the dual-positive specimens, 125 (93.3%) were positive for Candida and Aspergillus species, with concordances between culture and PCR/ESI-MS results being 84 (67.2%) at the species level and 109 (87.2%) at the genus level. In addition, 243 (35.2%) and 30 (4.3%) specimens were positive only by PCR/ESI-MS or by culture, respectively (odds ratio [OR] = 11.95, 95% confidence interval [CI] = 7.90 to 18.17, P = 0.0000). Codetection of fungal organisms was noted in 23 (3.3%) specimens by PCR/ESI-MS, which was significantly higher than the 4 (0.6%) in which they were noted by culture (OR = 5.91, 95% CI = 1.93 to 20.27, P = 0.0002). Among 53 specimens in which cultures failed because of bacterial overgrowth, at least one fungus was identified in 26 specimens (47.3%) by PCR/ESI-MS. PCR/ESI-MS provides an advanced tool for rapid and sensitive detection, identification, and determination of the distribution of fungal organisms directly from BAL fluid specimens. Moreover, it detected fungal organisms in specimens in which cultures failed because of bacterial overgrowth. The clinical relevance of the significantly higher detection rate of fungal organisms by PCR/ESI-MS merits further investigation.

The study aimed to investigate the prevalence of various serotypes and extended-spectrum β-lactamase-producing features of Salmonella strains and to determine the antimicrobial susceptibility of 256 Salmonella strains other than Salmonella serotype Typhi, which were isolated at 12 university hospitals in Korea. We identified 46 serotypes of Salmonella spp. Serogroup D was the most common (39.5%), followed by B (32.4%), C (22.7%), E (2.7%), A (2.3%), and G (0.4%). The three most common Salmonella serotypes were Enteritidis (36.3%), Typhimurium (16.8%), and Infantis (7.8%). Six strains that belonged to serotype Paratyphi A and nine that belonged to serotype Paratyphi B were also detected. The 256 Salmonella strains had a 38.7% rate of resistance to ampicillin, 23.0% to chloramphenicol, 8.2% to cefotaxime, 8.6% to ceftriaxone, and 6.3% to trimethoprim-sulfamethoxazole. The antimicrobial resistance rates of Salmonella serogroups B and D were higher than those of the other serogroups. Seven isolates carried blaCTX-M: four CTX-M-15, two CTX-M-14, and one CTX-M-3.

Over a 5-month period between the end of June and the beginning of November in 2015, a KPC-producing Enterobacteriaceae outbreak occurred in a general hospital in Busan, South Korea, being associated with a total of 50 clinical isolates from 47 patients. Multilocus sequence typing and pulsed-field gel electrophoresis were carried out for strain typing and whole-genome sequencing was performed to characterize the plasmids. A clonal spread of K. pneumoniae sequence type 307 (ST307) carrying a self-transferable IncX3-type plasmid harboring blaKPC-2 was responsible for the outbreak. Sporadic emergence of K. pneumoniae ST697 carrying an IncFII-type plasmid and a ST11 isolate harboring a small plasmid devoid of any known origin of replication were observed to be associated with blaKPC-3, but no further dissemination of these strains was identified. The results indicated a healthcare-associated infection associated with a blaKPC-harboring plasmid dissemination and a clonal spread of KPC-producing Enterobacteriaceae.

Vibrio species are well known as motile, mostly oxidase-positive, facultative anaerobic Gram-negative bacteria. They are abundant in aquatic environments and are a common cause of human infections including diarrhea, soft tissue diseases, and bacteremia. Here, two Gram-negative bacteria, designated M12-1144T and M12-1181, were isolated from human clinical specimens and identified using a polyphasic taxonomic approach. Phylogenetic study based on 16S rRNA gene sequence analysis revealed that the isolates belong to the genus Vibrio, and are closely related to Vibrio metschnikovii KCTC 32284T (98.3%) and Vibrio cincinnatiensis KCTC 2733T (97.8%). The major fatty acids were summed feature 3 (C16:1 ω7c/C16:1 ω6c, 38.0%), C16:0 (23.0%), and summed feature 8 (C18:1 ω7c or C18:1 ω6c, 19.3%) and major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The G + C content of the genomic DNA was determined to be 44.1 mol%. DNA–DNA relatedness between the two newly isolated strains and V. metschnikovii KCTC 32284T and V. cincinnatiensis KCTC 2733T was between 42.6 to 47.5%. The similarities of genome-to-genome distance between M12-1144T and related species ranged from 18.4-54.8%. Based on these results, a new species of the genus Vibrio, Vibrio injenensis is proposed. The type strain is M12-1144 T(=KCTC 32233T =JCM 30011T).

Introduction.Streptococcus pneumoniaeis an important pathogen with high morbidity and mortality rates. The aim of this study was to evaluate the distribution of common serotypes and antimicrobial susceptibility ofS. pneumoniaein Korea.Methods. A total of 378 pneumococcal isolates were collected from 2008 through 2014. We analyzed the serotype and antimicrobial susceptibility for both invasive and noninvasive isolates.Results. Over the 7 years, 3 (13.5%), 35 (10.8%), 19A (9.0%), 19F (6.6%), 6A (6.1%), and 34 (5.6%) were common serotypes/serogroups. The vaccine coverage rates of PCV7, PCV10, PCV13, and PPSV23 were 21.4%, 23.3%, 51.9%, and 62.4% in all periods. The proportions of serotypes 19A and 19F decreased and nonvaccine serotypes increased between 2008 and 2010 and 2011 and 2014. Of 378S. pneumoniaeisolates, 131 (34.7%) were multidrug resistant (MDR) and serotypes 19A and 19F were predominant. The resistance rate to levofloxacin was significantly increased (7.2%).Conclusion. We found changes of pneumococcal serotype and antimicrobial susceptibility during the 7 years after introduction of the first pneumococcal vaccine. It is important to continuously monitor pneumococcal serotypes and their susceptibilities.

Multistage veinlet cataclastic rocks, composed of aphanitic veins typical of pseudotachylyte and unconsolidated fault gouge, and sediment veins composed of alluvial deposits are widely developed within a fault shear zone (

Background We investigated the prevalence of plasmid-mediated quinolone resistance and its association with extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase in Enterobacteriaceae. Methods A total of 347 non-duplicated isolates of Enterobacteriaceae were collected between August and October 2006 from 2 hospitals. Qnr determinant screening was conducted using PCR amplification, and all positive results were confirmed by direct sequencing. Qnr-positive strains were determined on the basis of the presence of ESBL and AmpC beta-lactamase genes. Results The qnr gene was detected in 47 of 347 clinical Enterobacteriaceae isolates. Among the 47 qnr-positive strains, Klebsiella pneumoniae (N=29) was the most common, followed by Escherichia coli (N=6), Enterobacter cloacae (N=6), Citrobacter freundii (N=5), and Enterobacter aerogenes (N=1). These isolates were identified as qnrA1 (N=6), 8 qnrB subtypes (N=40), and qnrS1 (N=1). At least 1 ESBL was detected in 38 of the 47 qnr-positive strains. Qnr-positive strains also showed high positive rates of ESBL or AmpC beta-lactamase, such as TEM, SHV, CTX-M, and DHA. DHA-1 was detected in 23 of 47 qnr-positive strains, and this was co-produced with 1 qnrA1 and 22 qnrB4. Strains harboring MIR-1T and CMY were also detected among the qnr-positive strains. Antimicrobial-resistance rates of qnr-positive strains to ciprofloxacin, levofloxacin, norfloxacin, nalidixic acid, and moxifloxacin were 51.1%, 46.8%, 46.8%, 74.5%, and 53.2%, respectively. Conclusions The qnr genes were highly prevalent in Enterobacteriaceae, primarily the qnrB subtypes. They were closely associated with EBSL and AmpC beta-lactamase.

Introduction Coagulase-negative staphylococcus (CoNS) is the most common pathogen in continuous ambulatory peritoneal dialysis (CAPD)–associated peritonitis. There is no well-organized, standardized database for CoNS, and few studies have used gene sequencing in reporting species distribution in CAPD peritonitis. In the present study, we used 3 housekeeping genes to evaluate the prevalence of CoNS isolated from CAPD peritonitis episodes and to estimate the accuracy of, and the characteristic differences between, these genes for species identification. Methods All 51 non-duplicated CoNS isolates obtained from CAPD peritonitis between April 2006 and May 2008 were used. The strains were identified by polymerase chain reaction and by direct sequencing using the 16S ribosomal RNA (rRNA), tuf, and sodA genes. We determined species distribution, and using selected databases, we analyzed the characteristics and diagnostic utility of the individual genes for species identification. Results In GenBank (National Institutes of Health, Bethesda, MD, USA), we found 49 type or reference strains for CoNS 16S rRNA, 17 for tuf, and 46 for sodA, and we used those data for sequence-similarity comparisons with CAPD isolates. Among our 51 strains, S. epidermidis (66.7%) was the most common, followed by S. haemolyticus (11.8%), S. warneri (7.8%), S. caprae (5.9%), S. capitis (3.9%), and S. pasteuri (2.0%). For 1 strain, different species results were obtained with each gene. The identification rates with 16S rRNA, sodA, and tuf gene sequencing were 84.0%, 96.0%, and 92.2% respectively. The discrimination capability of 16S rRNA gene was lower in a few individual species, and for the sodA gene, the percentage similarity to sequences from reference strains was also lower. The tuf gene had excellent identification capacity, but relatively few type strains are available in public databases. The 16S rRNA gene did not discriminate between S. caprae and S. capitis. The sodA gene showed a similarity rate that was lower than that for sequences of the 16S rRNA gene. The tuf type strain sequences for S. caprae and S. pasteuri are not available in public databases. Conclusions The sodA, tuf, and 16S rRNA genes were very useful for CoNS identification. Each has its own characteristics of similarity, discriminative power, and inclusion in databases.

Background: Optimal blood culture performance is critical for successful diagnosis and treatment of sepsis. To understand the sta- tus of blood culture, we investigated several aspects of the procedure at 9 university hospitals. Methods: The process of ordering blood culture sets and sampling volume for adults and children was investigated from January 2010 to April 2010, while the positive rate of detection and growth of skin contaminants were compared in 2009. Microbial growth in aerobic and anaerobic bottles was investigated prospectively. Results: A majority of the hospitals used 2 sets of bottles for adults and 1 bottle for children. The average blood volume in each set was 7.7 mL for adults and 2.1 mL for children. The positive rate of microorganisms was 8.0%, and the isolation rate of the normal flora of the skin was 2.1%. Bacterial growth rates in aerobic and anaerobic bottles only were 31.8% and 24.5% respectively. Conclusions: Ordering blood culture sets and sampling volumes did not comply with CLSI guidelines. However, the rate of positive cultures and skin contamination rates were acceptable. Anaerobic bottles are useful in enhancing the yield of microorganisms.

In this paper we design an irregular low-density parity-check (LDPC) code for multiple-input multiple-output (MIMO) systems, using a simple extrinsic information transfer (EXIT) chart method. The MIMO systems considered are the optimal maximum a posteriori probability (MAP) detector and the suboptimal minimum mean square error soft-interference cancellation (MMSE-SIC) detector. The MIMO detector and the LDPC decoder exchange soft information and form a turbo iterative receiver. The EXIT charts are used to obtain the edge degree distribution of the irregular LDPC code which is optimized for the MIMO detector. It is shown that the performance of the designed LDPC code is better than that of conventional LDPC code which was optimized for either the Additive White Gaussian Noise (AWGN) channel or the MIMO channel without an explicit consideration of the given detector structure.

Oligonucleotide chips targeting the bacterial internal transcribed spacer region (ITS) of the 16S-23S rRNA gene, which contains genus- and species-specific regions, were developed and evaluated. Forty-three sequences were designed consisting of 1 universal, 3 Gram stain-specific, 9 genus-specific, and 30 species-specific probes. The specificity of the probes was confirmed using bacterial type strains including 54 of 52 species belonging to 18 genera. The performance of the probes was evaluated using 825 consecutive samples that were positive by blood culture in broth medium. Among the 825 clinical specimens, 708 (85.8%) were identified correctly by the oligonucleotide chip. Most (536 isolates, or 75.7%) were identified as staphylococci, Escherichia coli , or Klebsiella pneumoniae . Thirty-seven isolates (4.5%) did not bind to the corresponding specific probes. Most of these also were staphylococci, E. coli , or K. pneumoniae and accounted for 6.3% of total number of the species. Sixty-two specimens (7.5%) did not bind the genus- or species-specific probes because of lack of corresponding specific probes. Among them, Acinetobacter baumannii was the single most frequent isolate (26/62). The oligonucleotide chip was highly specific and sensitive in detecting the causative agents of bacteremia directly from positive blood cultures.

Erythromycin ribosome methyltransferase gene (erm) sequences of Mycobacterium massiliense and Mycobacterium bolletii isolates were newly investigated. Forty nine strains of M. massiliense that were analyzed in the present study had a deleted erm(41). Due to a frame-shift mutation, large deletion, and truncated C-terminal region, the Erm(41) of M. massiliense had only 81 amino acids encoded by 246 nucleotides. Corresponding to these findings, most of the M. massiliense isolates (89.8%) were markedly clarithromycin susceptible, but resistant strains invariably had a point mutation at the adenine (A2058 or A2059) in the peptidyltransferase region of the 23S rRNA gene, which is quite different from Mycobacterium abscessus and M. bolletii. In addition, erm(41) sequences of M. massiliense were more conserved than those of M. abscessus and M. bolletii. The results of species identification using erm(41) showed concordant results with those of multi-locus sequence analysis (rpoB, hsp65, sodA and 16S-23S ITS) where there were originally inconsistent results between rpoB and hsp65 sequence analysis in previous research. Therefore, erm(41) PCR that was used in the present study can be efficiently used to simply differentiate M. massiliense from M. abscessus and M. bolletii.

Lineage switch is a very rare event in blastic crisis of chronic myelogenous leukemia (CML-BC). To our knowledge, only three cases of lineage switch between lymphoid and myeloid/myelomonocytic lineages have been reported in the literature. Here, we report a novel case of imatinib-resistant CML-BC, in which the blast lineage switched from biphenotypic to B-lymphoid.

Plasmodium vivax merozoite surface protein 1 (PvMSP-1) has been considered a major candidate for the development of an antimalaria vaccine, but the molecule exhibits antigenic diversity among isolates. The extent of genetic polymorphism in the region between interspecies conserved blocks 4 and 5 (ICB4 and ICB5) of the PvMSP-1 gene was analyzed for 30 Korean isolates. Two genotypes, SK-A and SK-B, were identified on the basis of amino acid substitution. Almost all the amino acid sequences of the Korean isolates were nearly identical to those of the Solomon Island isolate Solo-83 (97.8 to 99.9% similarity) and Philippine isolates Ph-79, Ph-52-2, and Ph-49 (97.3 to 99.8% similarity). Also, we report two sequences in the isolates that were characterized on the basis of restriction fragment length polymorphism (RFLP). The RFLP profiles following digestion with the DraI restriction enzyme produced two distinguishable patterns. This study might be the first report of the region between ICB4 and ICB5 of the MSP-1 gene of P. vivax in South Korea.

The prevalence of toxigenic Clostridium difficile in Korea has been reported to be approximately 60–80 %. Although the prevalence of the tcdA−tcdB+ C. difficile strain was less then 5 % prior to the year 2000, it has become an emerging nosocomial pathogen in Korea. Therefore, we have attempted to determine the multicentre nationwide prevalence of tcdA+tcdB+ and tcdA−tcdB+ C. difficile for epidemiological purposes. C. difficile strains (n=724, 30 from 2000, 80 from 2001, 74 from 2002, 76 from 2003, 179 from 2004, 285 from 2005) were obtained retrospectively from January 2000 to December 2005 from in-patients at 6 hospitals, all of whom were suspected of having C. difficile-associated disease (CDAD), colitis or pseudomembranous colitis. The numbers of participating hospitals varied yearly (1 in 2000, 2 in 2001–2003, 3 in 2004, 5 in 2005). The hospitals were located in Seoul (n=4), Kyunggi Province (n=1) and Busan (n=1), Korea. PCR assays for tcdA and tcdB genes were conducted using 724 unduplicated C. difficile isolates. The mean prevalence of tcdA+tcdB+ and tcdA−tcdB+ C. difficile strains over the 6 years was 51.8 % (38.4–59.3 %) and 25.8 %(10–56.0 %), respectively. The mean prevalence of tcdA−tcdB+ C. difficile strains was less than 7 % until 2002, but began to increase in 2003 (13.2 %) and achieved a peak in 2004 (50.3 %). In 2005, the mean prevalence of tcdA+tcdB+ and tcdA−tcdB+ C. difficile strains was 47.7 % (30.9–60.3 %) and 27.0 % (17.6–54.8 %), respectively. This nationwide epidemiological study showed that tcdA−tcdB+ C. difficile strains have already spread extensively throughout Korea, and our results provide basic data regarding the controversies currently surrounding the toxigenicity of tcdA−tcdB+ C. difficile. The use of enzyme immunoassays capable of detecting both TcdA and TcdB is strongly recommended for the diagnosis of CDAD in microbiology laboratories, in order to control the spread of the tcdA−tcdB+ strains of C. difficile.

This paper presents an interference cancellation and multipath mitigation algorithm for use in Global Positioning System (GPS) with an array antenna. It is shown that interference signals and multipath signals are effectively suppressed using a serial subspace projection method without any knowledge of the incoming directional information. After the subspace projections, a beamformer is used to maximize the SNR of the received signal. The enhancement in the performance is presented in terms of the cross correlation value and beam patterns.

Background : Following induction chemotherapy for AML, a sensitive determination of minimal residual disease (MRD) in patients achieving complete remission (CR) should enable the detection of early relapse. This study was designed to verify if quantitative assessment of the Wilms’ tumor (WT1) gene by real time polymerase chain reaction (RQ-PCR) can be used as a marker for MRD detection during the monitoring of AML. Methods : WT1 gene expression was quantified by RQ-PCR in 31 patients with AML at diagnosis (27 patients) and during follow-up (29 patients) relative to ABL control gene. In four patients, the WT1 gene expression was analyzed in comparison to a second PCR marker, PML-RARA fusion transcript. Prognostic significance of WT1 gene expression was analyzed at diagnosis and at the primary CR evaluation. Longitudinal WT1 gene analysis was performed in 17 AML patients. Results : At diagnosis, WT1 gene expression exceeded the control level in all of the patients. Higher levels of WT1 gene expression were not associated with shorter event free survival or overall survival at diagnosis. Higher levels of WT1 gene expression were associated with shorter event free survival after induction chemotherapy. Relapse was observed in eight of 17 patients analysed longitudinally, and an increase of WT1 gene expression preceded morphologic relapse in four patients with the fusion transcript negative. Concomitant monitoring of PML-RARA fusion transcript reveals the lack of a significant correlation withWT1 gene expression. Conclusions : Quantitation of WT1 gene expression could be used for MRD monitoring of AML and for the early detection of relapse, especially in patients lacking specific molecular markers. (Korean J Lab Med 2007;27:305-12)

Background : fms-like tyrosine kinase (FLT3 ), a member of the class III receptor tyrosine kinases, regulates the proliferation and differentiation of hematopoietic stem cells. An internal tandem dupli- cation of the FLT3 gene (FLT3/ITD) has been reported in acute myelogenous leukemia (AML) and may be associated with a poor prognosis. In this study we determined the prevalence and prognostic significance of FLT3/ITD in adult AML patients. Methods : This study included 52 adult de novo AML. Exon 14 and 15 of the FLT3 gene were am- plified by PCR and the PCR products were analyzed by 3730XL DNA analyzer (Applied Biosystems, USA) and GeneMapper Software. Results : FLT3/ITD was found in 15 (28.8%) of the 52 AML patients. The presence of FLT3/ITD was significantly associated with absolute leukocyte counts (P=0.002) and bone marrow blast counts (P=0.036). FLT3/ITD was also more frequent in patients with normal karyotype (7 of 18) than in those with cytogenetic aberrations (3 of 25). Patients with t (15;17) showed a higher prevalence of FLT3/ ITD (2 of 7). FLT3/ITD was significantly associated with overall survival (P

Korean Abstract: 본 연구는 한국-쿠바 국교정상화 가능성에 대한 고찰을 시작으로 문화, 경제, 환경 분야의 현안들과 한국-쿠바 관계 증진을 위한 다양한 협력 방안들을 제시하고자 했다. 한국-쿠바 국교정상화가 빠른 시일 내에 이루어지기는 힘들다고 전제할 때, 우리가 던질 수 있는 최적의 질문은, 한국-쿠바 국교정상화를 위해 과연 ‘우리는 어떤 전략적 선택을 해야 하며, 양국 미래를 위해 어떤 협력 방안이 필요한가’다. 크게 두 가지 방법이 있다.먼저 한국이 일방적으로 양보하는 방법이다. 그러나 쿠바와의 국교정상화로 한국이 얻을 수 있는 이익이 압도적으로 크지 않은 상황에서 일방적 양보는 좋은 방법이라고 볼 수 없다. 윈-셋 변화와 우리가 사용할 수 있는 전략이 제한되어 있다는 점을 감안할 때 시한을 설정하거나 급하게 추진하는 것은 협상에 불리하게 작용할 수밖에 없다. 따라서 미국의 대 쿠바 엠바고 해제 여부와 긴밀한 관계를 갖는 시장의 변화, 쿠바 내 정치상황 변화 가능성 등을 감안할 때 협상 시한을 설정하거나 국교정상화를 서두르기 보다는 수교 여부와 상관없는 장기적 관계 강화의 수순을 밟는 것이 보다 현실적인 방안이라고 할 수 있을 것이다. 다른 하나는 상황의 변화를 꾀함으로써 쿠바가 양보할 수 있는 분위기를 조성하는 것이다. 몇 가지 방법의 제시가 가능하다. 첫째, ‘쿠바의 지도자 집단을 움직여라’ 이다. 지도자 집단의 의사가 가장 큰 영향을 미칠 수밖에 없는 쿠바의 외교정책결정구조를 감안하였을 때, 가장 손쉬운 방법은 쿠바의 정책결정자들에게 강력한 유인 요소를 제공함으로써 그들이 북한과의 관계를 한쪽으로 미루어 놓고 대한민국과의 국교를 정상화 하도록 유도하는 것이다. 노태우 정권 시기 북방정책의 결과물들이 터져 나올 때의 대한민국 외교가 사용했던 많은 방법들이 고려될 수 있을 것이다. 그러나 현 상황은 냉전 종식 직후와는 매우 다를 뿐 아니라, 쿠바의 정책결정자들 또한 의리와 명분을 중시하는 외교정책을 선호해 왔음을 감안할 때 현실적으로 쉽지 않은 방법이다. (후략)English Abstract: This study aims at finding out (international) cooperation methods in the fields of economics, culture and environment for promoting Korea-Cuba relations. Expected delaying of normalization of diplomatic relation between Korea and Cuba which it is not clear how soon this would happen, our research question focused on what strategic choices could be helpful to promote future relations for both countries. Of course, it could be consider a giving up strategy as one-side method in negotiation of normalization of diplomatic relation between S. Korea and Cuba. However, even if S. Korea could not obtain overwhelmingly large benefits with getting in a situation, unilateral concessions would not be considered in a good way for international negotiation. If we also recognize the limited situation with win-set changes, such as by using strategies that would set a deadline for when given that it has limited, or no choice, this kind of pushing strategy is to work as a disadvantage for better negotiation. Beyond giving up or pushing strategy, therefore we must consider the changing market situation in Cuba such as a closely related with a possibility of America’s embargo release for Cuba in near future and a possibility of changing political circumstances, etc. and rather than being in a hurry to step on a course for strengthening ties, we must take actions in a way of more realistic methods with a long-term process for making normalization of diplomatic relations for both countries. The other method is to creating special conditions by changing circumstances and inducing Cuban concession with some ways as below: First, as a little bit easy and a possible option, ‘Move Cuban Political Leaders’. We understand that Cuban political leaders have played a great role as important decision-making entity, especially in the context of diplomatic policy-making structure established more strongly and for a long time in particular after Cuban Revolution in 1959. By providing them strong incentives and leading them to keep away from N. Korea, it will lead to normalize diplomatic relations with S. Korea. However, in fact this strategy is not easy to realize as well, because Cuban diplomatic policies have been sustained for a long time on a basis of upholding loyalty and a cause for their foreign policies, especially with N. Korea as well.

Background It is known that the Y chromosome or Y-specific sequence is present in about 6% of Turner syndrome (TS) patients and that it predisposes them to gonadoblastoma formation with an estimated risk of 15-25%. In this study, we performed a polymerase chain reaction (PCR) in 32 patients with TS to detect Y-specific sequence. The results were compared with those obtained by the fluorescence in situ hybridaization (FISH) method. Methods Cytogenetic analysis was performed by phytohaemagglutinin (PHA)-stimulated peripheral lymphocyte cultures, using G-banding. DNA was extracted from peripheral blood for PCR. Seven different sets of oligonucleotide primers, sex determining region Y (SRY), zinc finger gene on the Y chromosome (ZFY), testis specific protein Y (TSPY), DYZ3, DYF49S1, RNA binding motif protein (RBM), and DYZ1, spanning on centromeres and short and long arms of the Y chromosome were used for PCR. FISH was carried out using X and Y chromosome enumeration probe for Xp11.1-q11.1 (DXZ1 locus) and Yp11.1-q11.1 (DYZ3 locus), respectively. Results Among 32 patients with TS, four (12.5%) were positive for Y specific sequence by PCR. Of these, two patients were detected previously by a cytogenetic analysis: 45,X/47,XYY and 45,X/46,XY. Only one Y specific sequence, DYZ3, was detected by PCR in the other two patients without cytogenetically obvious Y chromosome. Y signal was not detected by FISH for the last two patients. Conclusions It may be reasonable to consider using a PCR method to screen for Y-specific sequences in all patients with TS. Even though we did not demonstrate Y-signal by FISH in patients with PCR positive and cytogenetically no obvious Y chromosome, FISH may be another useful method in TS patient, and futher investigation is nessessary.

Background A sputum culture is the most reliable indicator of the infectiousness of pulmonary tuberculosis (PTB); however, a spontaneous sputum specimen may not be suitable. The aim of this study was to evaluate the infectious period in patients with non-drug-resistant (DR) PTB receiving adequate standard chemotherapy, using induced sputum (IS) specimens. Methods We evaluated the duration of infectiousness of PTB using a retrospective cohort design. Results Among the 35 patients with PTB, 22 were smear-positive. The rates of IS culture positivity from baseline to the sixth week of anti-tuberculosis medication in the smear-positive PTB group were 100%, 100%, 91%, 73%, 36%, and 18%, respectively. For smear-positive PTB cases, the median time of conversion to culture negativity was 35.0 days (range, 28.0-42.0 days). In the smear-negative PTB group (n=13), the weekly rates of positive IS culture were 100%, 77%, 39%, 8%, 0%, and 0%, respectively, and the median time to conversion to culture-negative was 21.0 days (range, 17.5-28.0 days). Conclusion The infectiousness of PTB, under adequate therapy, may persist longer than previously reported, even in patients with non-DR PTB.

The chromosome band 11q23 is a common target region of chromosomal translocation in different types of leukemia, including infantile leukemia and therapy-related leukemia. The target gene at 11q23, MLL, is disrupted by the translocation and becomes fused to various translocation partners. We report a case of AML with a rare 3-way translocation involving chromosomes 1, 9, and 11: t(1;9;11)(p34.2;p22;q23). A 3-yr-old Korean girl presented with a 5-day history of fever. A diagnosis of AML was made on the basis of the morphological evaluation and immunophenotyping of bone marrow specimens. Flow cytometric immunophenotyping showed blasts positive for myeloid lineage markers and aberrant CD19 expression. Karyotypic analysis showed 46,XX,t(1;9;11)(p34.2;p22;q23) in 19 of the 20 cells analyzed. This abnormality was involved in MLL/MLLT3 rearrangement, which was confirmed by qualitative multiplex reverse transcription-PCR and interphase FISH. She achieved morphological and cytogenetic remission after 1 month of chemotherapy and remained event-free for 6 months. Four cases of t(1;9;11)(v;p22;q23) have been reported previously in a series that included cases with other 11q23 abnormalities, making it difficult to determine the distinctive clinical features associated with this abnormality. To our knowledge, this is the first description of t(1;9;11) with clinical and laboratory data, including the data for the involved genes, MLL/MLLT3.