Xpert MTB/RIF Assay as a Substitute for Smear Microscopy in an Intermediate-Burden Setting.

RATIONALE: Use of Xpert MTB/RIF assay as a substitute for smear microscopy in routine clinical practice remains unexplored in an intermediate-tuberculosis-burden setting. OBJECTIVES: To compare the diagnostic performance of Xpert and smear microscopy, based on sampling time and location, correlation of Xpert semiquantitative category with smear grade and time to culture positivity, and compliance of reporting time with defined standard time. METHODS: Consecutive sputum samples collected from 2,952 suspected pulmonary tuberculosis patients over a 3-year period were tested by Xpert, smear microscopy, and liquid culture as part of routine diagnostics in South Korea. MEASUREMENTS AND MAIN RESULTS: Based on the analysis of a single sputum specimen per patient, of 2,952 samples, 263 (8.9%) were culture-confirmed tuberculosis and 265 (9.0%) were nontuberculous mycobacteria. The overall sensitivity and specificity were 74.1% and 97.5% for Xpert versus 38.8% and 96.7% for smear microscopy, respectively (P < 0.0001; P > 0.05). Of 82 smear-positive nontuberculous mycobacteria, 81 (98.8%) were accurately excluded by Xpert. Sampling time and location significantly affected the performance of smear microscopy but not that of Xpert. Xpert semiquantitative category strongly correlated with smear grade (γGoodman-Kruskal = 0.982; P < 0.0001) and time to culture positivity (γGoodman-Kruskal = -0.962; P < 0.0001). Median reporting time and its compliance rate within 24 hours were 3.1 hours and 96.3% for Xpert versus 19.1 hours and 88.7% for smear microscopy, respectively (P < 0.0001; P < 0.05). CONCLUSIONS: Xpert provides faster, more stable, and superior results compared with smear microscopy, in addition to its strong correlation with smear grade. Xpert might replace smear microscopy as the first-line diagnostic test for pulmonary tuberculosis in routine clinical practice in an intermediate-burden setting.

Molecular Diagnosis of Taenia saginata Tapeworm Infection in 2 Schoolchildren, Myanmar.

Taenia saginata is the most common human tapeworm worldwide but has been unknown in Myanmar. In 2017, fecal examination in Yangon, Myanmar, revealed eggs of Taenia species in 2 children from a monastic school. Several proglottids expelled after medication with praziquantel were morphologically and molecularly confirmed to be T. saginata tapeworms.

Antifungal susceptibilities to amphotericin B, triazoles and echinocandins of 77 clinical isolates of cryptic Aspergillus species in multicenter surveillance in Korea.

We investigated the in vitro antifungal susceptibilities of cryptic Aspergillus species from nine Korean hospitals. Based on the CLSI epidemiological cutoff values, resistance rates to amphotericin B, itraconazole, voriconazole, posaconazole and caspofungin were as follows: A. awamori (34 isolates; all 0%), A. tubingensis (22; 0%, 4.5%, 0%, 0%, and 0%, respectively), A. sydowii (16; 0%, 6.3%, 0%, 0%, and 6.3%), A. lentulus (2; 50%, 0%, 100%, 50%, and 0%), and A. tamarii (2; all 0%). A. calidoustus (one isolate) showed resistance to multiple drugs. Thus, cryptic species identification can be mandatory for clinically important Aspergillus isolates, with their susceptibility data.

Diversity of clinical isolates of Aspergillus terreus in antifungal susceptibilities, genotypes and virulence in Galleria mellonella model: Comparison between respiratory and ear isolates.

We analyzed the antifungal susceptibility profiles, genotypes, and virulence of clinical Aspergillus terreus isolates from six university hospitals in South Korea. Thirty one isolates of A. terreus, comprising 15 respiratory and 16 ear isolates were assessed. Microsatellite genotyping was performed, and genetic similarity was assessed by calculating the Jaccard index. Virulence was evaluated by Galleria mellonella survival assay. All 31 isolates were susceptible to itraconazole, posaconazole, and voriconazole, while 23 (74.2%) and 6 (19.4%) showed amphotericin B (AMB) minimum inhibitory concentrations (MICs) of ≤ 1 mg/L and > 4 mg/L, respectively. Notably, respiratory isolates showed significantly higher geometric mean MICs than ear isolates to AMB (2.41 vs. 0.48 mg/L), itraconazole (0.40 vs. 0.19 mg/L), posaconazole (0.16 vs. 0.08 mg/L), and voriconazole (0.76 vs. 0.31 mg/L) (all, P <0.05). Microsatellite genotyping separated the 31 isolates into 27 types, but the dendrogram demonstrated a closer genotypic relatedness among isolates from the same body site (ear or respiratory tract); in particular, the majority of ear isolates clustered together. Individual isolates varied markedly in their ability to kill infected G. mellonella after 72 h, but virulence did not show significant differences according to source (ear or respiratory tract), genotype, or antifungal susceptibility. The current study shows the marked diversity of clinical isolates of A. terreus in terms of antifungal susceptibilities, genotypes and virulence in the G. mellonella model, and ear isolates from Korean hospitals may have lower AMB or triazole MICs than respiratory isolates.

Evaluation of matrix-assisted laser desorption/ionization time-of-fight mass spectrometry for identification of 345 clinical isolates of Aspergillus species from 11 Korean hospitals: comparison with molecular identification.

We evaluated the ability of the Filamentous Fungi Library 1.0 of the MALDI-TOF MS Biotyper system to identify 345 clinical Aspergillus isolates from 11 Korean hospitals. Compared with results of the internal transcribed spacer region sequencing, the frequencies of correct identification at the species-complex level were 94.5% and 98.8% with cutoff values of 2.0 and 1.7, respectively. Compared with results of ß-tubulin gene sequencing, the frequencies of correct identification at the species level were 96.0% (cutoff 2.0) and 100% (cutoff 1.7) for 303 Aspergillus isolates of five common, non-cryptic species, but only 4.8% (cutoff 1.7) and 0% (cutoff 2.0) for 42 Aspergillus isolates of six cryptic species (identifiable by ß-tubulin or calmodulin sequencing). These results show that the MALDI Biotyper using the Filamentous Fungi Library version 1.0 enables reliable identification of the majority of common clinical Aspergillus isolates, although the database should be expanded to facilitate identification of cryptic species.

Comparison of the Bruker Biotyper and VITEK MS Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Systems Using a Formic Acid Extraction Method to Identify Common and Uncommon Yeast Isolates.

BACKGROUND: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and accurate identification of clinical yeast isolates. In-tube formic acid/acetonitrile (FA/ACN) extraction is recommended prior to the analysis with MALDI Biotyper, but the direct on-plate FA extraction is simpler. We compared the Biotyper with the VITEK MS for the identification of various clinically relevant yeast species, focusing on the use of the FA extraction method. METHODS: We analyzed 309 clinical isolates of 42 yeast species (four common Candida species, Cryptococcus neoformans, and 37 uncommon yeast species) using the Biotyper and VITEK MS systems. FA extraction was used initially for all isolates. If 'no identification' result was obtained following the initial FA extraction, these samples were then retested by using FA (both systems, additive FA) or FA/ACN (Biotyper only, additive FA/ACN) extraction. These results were compared with those obtained by sequence-based identification. RESULTS: Both systems correctly identified all 158 isolates of the four common Candida species after the initial FA extraction. The Biotyper correctly identified 8.7%, 30.4%, and 100% of 23 C. neoformans isolates after performing initial FA, additive FA, and FA/ACN extractions, respectively, while VITEK MS identified all C. neoformans isolates after the initial FA extraction. Both systems had comparable identification rates of 37 uncommon yeast species (128 isolates), following the initial FA (Biotyper, 74.2%; VITEK MS, 73.4%) or additive FA (Biotyper, 82.0%; VITEK MS, 73.4%). CONCLUSIONS: The identification rate of most common and uncommon yeast isolates is comparable between simple FA extraction/Biotyper method and VITEK MS methods, but FA/ACN extraction is necessary for C. neoformans identification by Biotyper.

Multiplex Real-Time PCR Assay Targeting Eight Parasites Customized to the Korean Population: Potential Use for Detection in Diarrheal Stool Samples from Gastroenteritis Patients.

Intestinal parasitic diseases occur worldwide and can cause diarrhea or gastroenteritis; however, their diagnosis is quite difficult, especially in low-endemism countries. We developed a multiplex real-time PCR assay for detection of eight intestinal parasites and prospectively evaluated it for patients with gastroenteritis. The assay targeted Cryptosporidium parvum, Giardia lamblia, Entamoeba histolytica, Blastocystis hominis, Dientamoeba fragilis, Clonorchis sinensis, Metagonimus yokogawai, and Gymnophalloides seoi. Performance characteristics were evaluated based on recovery after DNA extraction, analytical sensitivity, specificity, reproducibility, cross-reactivity, and interference characteristics. Clinical performance was validated against microscopy on 123 diarrheal samples. The assay demonstrated strong correlations between DNA concentrations and Ct values (R2, 0.9924-0.9998), and had a high PCR efficiency (83.3%-109.5%). Polymerase chain reactions detected as few as 10-30 copies of genomic DNA, and coefficient of variance was 0-7%. There was no cross-reactivity to the other 54 microorganisms tested. Interference occurred only in presence of high concentrations of erythrocytes or leukocytes. This assay had a higher correct identification rate (100.0% vs. 90.2%) and lower incorrect ID rate (0.0% vs. 9.8%) when compared to microscopy. Overall, this assay showed a higher sensitivity (100.0%; 95% confidence interval [CI] of 80.5-100.0) than microscopy (29.4%; 95% CI 10.31-55.96), and the specificity levels were comparable for both methods (100.0%; 95% CI 96.58-100.0). This newly developed multiplex real-time PCR assay offers a potential use for detecting intestinal parasitic pathogens customized to the Korean population.

Coexistence of JAK2 and CALR mutations and their clinical implications in patients with essential thrombocythemia.

Janus kinase 2 (JAK2) and calreticulin (CALR) constitute the two most frequent mutations in essential thrombocythemia (ET), and both are reported to be mutually exclusive. Hence, we examined a cohort of 123 myeloproliferative neoplasm (MPN) patients without BCR-ABL1 rearrangement and additional ET patients (n=96) for coexistence of JAK2 and CALR mutations. The frequency of CALR mutations was 20.3% in 123 MPN patients; 31.1% in ET (n=74), 25% in primary myelofibrosis (n=4) and 2.2% in polycythemia vera (n=45). JAK2 and CALR mutations coexisted in 7 (4.2%) of 167 ET patients. Clinical characteristics, progression-free survival (PFS), and elapsed time to achieve partial remission across 4 groups (JAK2+/CALR+, JAK2+/CALR-, JAK2-/CALR+, JAK2-/CALR-) were reviewed. The JAK2+/CALR- group had higher leukocyte counts and hemoglobin levels and more frequent thrombotic events than JAK2-/CALR- group. JAK2 mutations have a greater effect on the disease phenotype and the clinical features of MPN patients rather than do CALR mutation. JAK2+ groups showed a tendency of poor PFS than JAK2- groups regardless of CALR mutation. CALR+ was a predictor of late response to the treatment. Our study also showed that thrombosis was more frequent in ET patients with type 2 CALR mutations than in those with type 1 CALR mutations.

Germline TP53 Mutation and Clinical Characteristics of Korean Patients With Li-Fraumeni Syndrome.

BACKGROUND: Little is known of the mutation and tumor spectrum of Korean patients with Li-Fraumeni syndrome (LFS). Owing to the rarity of LFS, few cases have been reported in Korea thus far. This study aimed to retrospectively review the mutations and clinical characteristics of Korean patients with LFS. METHODS: TP53 mutation was screened in 89 unrelated individuals at the Samsung Medical Center in Korea, from 2004 to 2015. Six additional mutation carriers were obtained from the literature. RESULTS: We identified nine different mutations in 14 Korean patients (male to female ratio=0.3:1). Two such frameshift mutations (p.Pro98Leufs*25, p.Pro27Leufs*17) were novel. The recurrent mutations were located at codons 31 (n=2; p.Val31Ile), 175 (n=3; p.Arg175His), and 273 (n=4; p.Arg273His and p.Arg273Cys). The median age at the first tumor onset was 25 yr. Ten patients (71%) developed multiple primary tumors. A diverse spectrum of tumors was observed, including breast (n=6), osteosarcoma (n=4), brain (n=4), leukemia (n=2), stomach (n=2), thyroid (n=2), lung (n=2), skin (n=2), bladder (n=1), nasal cavity cancer (n=1), and adrenocortical carcinoma (n=1). CONCLUSIONS: There was considerable heterogeneity in the TP53 mutations and tumor spectrum in Korean patients with LFS. Our results suggest shared and different LFS characteristics between Caucasian and Korean patients. This is the first report on the mutation spectrum and clinical characteristics from the largest series of Korean LFS patients.

Resistance Mechanisms and Clinical Features of Fluconazole-Nonsusceptible Candida tropicalis Isolates Compared with Fluconazole-Less-Susceptible Isolates.

We investigated the azole resistance mechanisms and clinical features of fluconazole-nonsusceptible (FNS) isolates of Candida tropicalis recovered from Korean surveillance cultures in comparison with fluconazole-less-susceptible (FLS) isolates. Thirty-five clinical isolates of C. tropicalis, comprising 9 FNS (fluconazole MIC, 4 to 64 µg/ml), 12 FLS (MIC, 1 to 2 µg/ml), and 14 control (MIC, 0.125 to 0.5 µg/ml) isolates, were assessed. CDR1, MDR1, and ERG11 expression was quantified, and the ERG11 and UPC2 genes were sequenced. Clinical features of 16 patients with FNS or FLS bloodstream isolates were analyzed. Both FNS and FLS isolates had >10-fold higher mean expression levels of CDR1, MDR1, and ERG11 genes than control isolates (P values of <0.02 for all). When FNS and FLS isolates were compared, FNS isolates had 3.4-fold higher mean ERG11 expression levels than FLS isolates (P = 0.004), but there were no differences in those of CDR1 or MDR1 Of all 35 isolates, 4 (2 FNS and 2 FLS) and 28 (8 FNS, 11 FLS, and 9 control) isolates exhibited amino acid substitutions in Erg11p and Upc2p, respectively. Both FNS and FLS bloodstream isolates were associated with azole therapeutic failure (3/4 versus 4/7) or uncleared fungemia (4/6 versus 4/10), but FNS isolates were identified more frequently from patients with previous azole exposure (6/6 versus 3/10; P = 0.011) and immunosuppression (6/6 versus 3/10; P = 0.011). These results reveal that the majority of FNS C. tropicalis isolates show overexpression of CDR1, MDR1, and ERG11 genes, and fungemia develops after azole exposure in patients with immunosuppression.

Molecular identification and amphotericin B susceptibility testing of clinical isolates of Aspergillus from 11 hospitals in Korea.

BACKGROUND: We investigated the species distribution and amphotericin B (AMB) susceptibility of Korean clinical Aspergillus isolates by using two Etests and the CLSI broth microdilution method. METHODS: A total of 136 Aspergillus isolates obtained from 11 university hospitals were identified by sequencing the internal transcribed spacer (ITS) and ß-tubulin genomic regions. Minimal inhibitory concentrations (MICs) of AMB were determined in Etests using Mueller-Hinton agar (Etest-MH) and RPMI agar (Etest-RPG), and categorical agreement with the CLSI method was assessed by using epidemiological cutoff values. RESULTS: ITS sequencing identified the following six Aspergillus species complexes: Aspergillus fumigatus (42.6% of the isolates), A. niger (23.5%), A. flavus (17.6%), A. terreus (11.0%), A. versicolor (4.4%), and A. ustus (0.7%). Cryptic species identifiable by ß-tubulin sequencing accounted for 25.7% (35/136) of the isolates. Of all 136 isolates, 36 (26.5%) had AMB MICs of ≥2 µg/mL by the CLSI method. The categorical agreement of Etest-RPG with the CLSI method was 98% for the A. fumigatus, A. niger, and A. versicolor complexes, 87% for the A. terreus complex, and 37.5% for the A. flavus complex. That of Etest-MH was ≤75% for the A. niger, A. flavus, A. terreus, and A. versicolor complexes but was higher for the A. fumigatus complex (98.3%). CONCLUSIONS: Aspergillus species other than A. fumigatus constitute about 60% of clinical Aspergillus isolates, and reduced AMB susceptibility is common among clinical isolates of Aspergillus in Korea. Molecular identification and AMB susceptibility testing by Etest-RPG may be useful for characterizing Aspergillus isolates of clinical relevance.

Seroepidemiology of Toxocariasis and Its Clinical Implications in Gwangju and Jeonnam-province, Korea.

We investigated the seroepidemiological, clinical, and laboratory characteristics of patients suspected to have toxocariasis in Gwangju and Jeonnam-province, Korea. In total, 228 specimens were analyzed for anti-Toxocara canis IgG at two university hospitals from 2010 to 2012. The overall seropositive rate was 67.1%, and the seropositive rates among the eosinophilic and non-eosinophilic groups were 76.1% (105/138) and 53.3% (48/90), respectively. Risk factors for eosinophilia and toxocariasis were male sex (odds ratios [OR]=2.632 and 3.477, respectively) and a history of ingesting raw meat (OR=2.884 and 3.274, respectively), especially raw cow liver (OR=2.089 and 10.038, respectively). T. canis seropositivity (OR=5.807, P=0.004) and a history of consuming raw cow liver (OR=2.766, P=0.052) were risk factors for organ involvement. The anti-T. canis IgG level showed weakly positive correlations with eosinophil counts (r=0.234, P<0.001) and the duration of eosinophilia (r=0.155, P=0.019). Although limited to the regions of Gwangju and Jeonnam-province, this study supports the opinion that toxocariasis is a reasonable focus as a cause of eosinophilia and that it is also associated with organ involvement.

The prognostic impact of mutations in spliceosomal genes for myelodysplastic syndrome patients without ring sideroblasts.

BACKGROUND: Mutations in genes that are part of the splicing machinery for myelodysplastic syndromes (MDS), including MDS without ring sideroblasts (RS), have been widely investigated. The effects of these mutations on clinical outcomes have been diverse and contrasting. METHODS: We examined a cohort of 129 de novo MDS patients, who did not harbor RS, for mutations affecting three spliceosomal genes (SF3B1, U2AF1, and SRSF2). RESULTS: The mutation rates of SF3B1, U2AF1, and SRSF2 were 7.0 %, 7.8 %, and 10.1 %, respectively. Compared with previously reported results, these rates were relatively infrequent. The SRSF2 mutation strongly correlated with old age (P < 0.001), while the mutation status of SF3B1 did not affect overall survival (OS), progression-free survival (PFS), or acute myeloid leukemia (AML) transformation. In contrast, MDS patients with mutations in U2AF1 or SRSF2 exhibited inferior PFS. The U2AF1 mutation was associated with inferior OS in low-risk MDS patients (P = 0.035). The SRSF2 mutation was somewhat associated with AML transformation (P = 0.083). CONCLUSION: Our findings suggest that the frequencies of the SF3B1, U2AF1, and SRSF2 splicing gene mutations in MDS without RS were relatively low. We also demonstrated that the U2AF1 and SRSF2 mutations were associated with an unfavorable prognostic impact in MDS patients without RS.

Comparison of AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR for Detection of Mycobacterium tuberculosis Complex in Routine Clinical Practice.

The AdvanSure tuberculosis/non-tuberculous mycobacterium (TB/NTM) PCR (LG Life Science, Korea) and COBAS TaqMan Mycobacterium tuberculosis (MTB) PCR (Roche Diagnostics, USA) are commonly used in clinical microbiology laboratories. We aimed to evaluate these two commercial real-time PCR assays for detection of MTB in a large set of clinical samples over a two-year period. AdvanSure TB/NTM PCR and COBAS TaqMan MTB PCR were performed on 9,119 (75.2%) and 3,010 (24.8%) of 12,129 (9,728 respiratory and 2,401 non-respiratory) MTB specimens, with 361 (4.0%) and 102 (3.4%) acid-fast bacilli (AFB)-positive results, respectively. In MTB culture, 788 (6.5%) MTB and 514 (4.2%) NTM were identified. The total sensitivity and specificity of the AdvanSure assay were 67.8% (95% confidence interval [CI], 63.9-71.6) and 98.3% (95% CI, 98.0-98.6), while those of the COBAS TaqMan assay were 67.2% (95% CI, 60.0-73.8) and 98.4% (95% CI, 97.9-98.9), respectively. The sensitivities and specificities of the AdvanSure and COBAS TaqMan assays for AFB-positive and AFB-negative samples were comparable. Furthermore, the AdvanSure assay showed fewer invalid results compared with the COBAS TaqMan assay (5.0 vs. 20.4 invalid results/1,000 tests, P<0.001). AdvanSure assay represents a comparable yet more reliable method than COBAS TaqMan for the identification of mycobacteria in routine clinical microbiology.

Feasible quantitative detection of cytomegalovirus from urine sediment in stem cell transplant patients.

BACKGROUND: Urine is an important source for the detection of infections caused by CMV in stem cell transplant patients. Currently, there is no agreement about the type of urine specimen. In order to investigate which is the better specimen type for quantitative detection of CMV, we compared the results from urine supernatant and sediment from the same patients. METHODS: Seventy urine specimens were collected from patients with hematological disorders or solid tumors. After performing shell vial culture, residual urine specimens were centrifuged. Then, 10 mL of each urine supernatant and sediment were taken and immediately frozen at -70 degrees C. Afterwards, archived urine specimens were thawed at room temperature and CMV-quantitative PCR was performed on both the supernatant and sediment fraction of urine. The results from each patient were reviewed for CMV antigenemia, blood shell vial culture, CMV-IgM or IgG, and clinical symptoms. RESULTS: CMV-qPCR results for the urine sediment fraction revealed a significant difference (p = 0.012) between the active CMV infection group and the latent CMV infection group. In addition, receiver operating characteristic curves for active CMV infection revealed that CMV-qPCR using urine sediment produced more accurate results than urine supernatant. CONCLUSIONS: These findings suggest that the sediment fraction of urine is a more suitable specimen in CMV-qPCR testing.

Direct confirmation of quiescence of CD34+CD38- leukemia stem cell populations using single cell culture, their molecular signature and clinicopathological implications.

BACKGROUND: The proliferating activity of a single leukemia stem cell and the molecular mechanisms for their quiescent property remain unknown, and also their prognostic value remains a matter of debate. Therefore, this study aimed to demonstrate the quiescence property and molecular signature of leukemia stem cell and their clinicopathological implications. METHODS: Single cell sorting and culture were performed in the various sets of hematopoietic stem cells including CD34+CD38- acute myeloid leukemia (AML) cell population (ASCs) from a total of 60 patients with AML, and 11 healthy controls. Their quiescence related-molecular signatures and clinicopathological parameters were evaluated in AML patients. RESULTS: Single cell plating efficiency of ASCs was significantly lower (8.6%) than those of normal hematopoietic stem cells i.e.: cord blood, 79.0%; peripheral blood, 45.3%; and bone marrow stem cell, 31.1%. Members of the TGFß super-family signaling pathway were most significantly decreased; as well as members of the Wnt, Notch, pluripotency maintenance and hedgehog pathways, compared with non ASC populations. mtDNA copy number of ASCs was significantly lower than that of corresponding other cell populations. However, our data couldn't support the prognostic value of the ASCs in AML. CONCLUSIONS: ASCs showed remarkable lower plating efficiency and slower dividing properties at the single cell level. This quiescence is represented as a marked decrease in the mtDNA copy number and also linked with down-regulation of genes in various molecular pathways.

Antifungal susceptibilities of bloodstream isolates of Candida species from nine hospitals in Korea: application of new antifungal breakpoints and relationship to antifungal usage.

We applied the new clinical breakpoints (CBPs) of the Clinical and Laboratory Standards Institute (CLSI) to a multicenter study to determine the antifungal susceptibility of bloodstream infection (BSI) isolates of Candida species in Korea, and determined the relationship between the frequency of antifungal-resistant Candida BSI isolates and antifungal use at hospitals. Four hundred and fifty BSI isolates of Candida species were collected over a 1-year period in 2011 from nine hospitals. The susceptibilities of the isolates to four antifungal agents were determined using the CLSI M27 broth microdilution method. By applying the species-specific CBPs, non-susceptibility to fluconazole was found in 16.4% (70/428) of isolates, comprising 2.6% resistant and 13.8% susceptible-dose dependent isolates. However, non-susceptibility to voriconazole, caspofungin, or micafungin was found in 0% (0/370), 0% (0/437), or 0.5% (2/437) of the Candida BSI isolates, respectively. Of the 450 isolates, 72 (16.0%) showed decreased susceptibility to fluconazole [minimum inhibitory concentration (MIC) ≥4 µg/ml]. The total usage of systemic antifungals varied considerably among the hospitals, ranging from 190.0 to 7.7 defined daily dose per 1,000 patient days, and fluconazole was the most commonly prescribed agent (46.3%). By Spearman's correlation analysis, fluconazole usage did not show a significant correlation with the percentage of fluconazole resistant isolates at hospitals. However, fluconazole usage was significantly correlated with the percentage of fluconazole non-susceptible isolates (r = 0.733; P = 0.025) or the percentage of isolates with decreased susceptibility to fluconazole (MIC ≥4 µg/ml) (r = 0.700; P = 0.036) at hospitals. Our work represents the first South Korean multicenter study demonstrating an association between antifungal use and antifungal resistance among BSI isolates of Candida at hospitals using the new CBPs of the CLSI.