Application of the Hollow-Fiber Infection Model to Personalized Precision Dosing of Isoniazid in a Clinical Setting.

BACKGROUND: The hollow-fiber infection model (HFIM) is a valuable tool for evaluating pharmacokinetics/pharmacodynamics relationships and determining the optimal antibiotic dose in monotherapy or combination therapy, but the application for personalized precision medicine in tuberculosis treatment remains limited. This study aimed to evaluate the efficacy of adjusted antibiotic doses for a tuberculosis patient using HFIM. METHODS: Model-based Bayesian forecasting was utilized to assess the proposed reduction of the isoniazid dose from 300 mg daily to 150 mg daily in a patient with an ultra-slow-acetylation phenotype. The efficacy of the adjusted 150-mg dose was evaluated in a time-to-kill assay performed using the bacterial isolate Mycobacterium tuberculosis (Mtb) H37Ra in a HFIM that mimicked the individual pharmacokinetic profile of the patient. RESULTS: The isoniazid concentration observed in the HFIM adequately reflected the target drug exposures simulated by the model. After 7 days of repeated dose administration, isoniazid killed 4 log10 Mtb CFU/mL in the treatment arm, while the control arm without isoniazid increased 1.6 log10 CFU/mL. CONCLUSION: Our results provide an example of the utility of the HFIM for predicting the efficacy of specific recommended doses of anti-tuberculosis drugs in real clinical setting.

Effects of Severe Acute Respiratory Syndrome Coronavirus Vaccination on Reinfection: A Community-Based Retrospective Cohort Study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a disease that is characterized by frequent reinfection. However, the factors influencing reinfection remain poorly elucidated, particularly regarding the effect of COVID-19 vaccination on preventing reinfection and its effects on symptomatology and the interval until reinfection. METHODS: This retrospective cohort study examined patients with severe acute respiratory syndrome coronavirus reinfection between January 2020 and February 2022. This study included patients aged >17 years who were reinfected at least 90 days between two infections with severe acute respiratory syndrome coronavirus. The main outcome measure was a reduction in symptoms during reinfection, and reinfection interval. RESULTS: Overall, 712 patients (average age: 40.52 ± 16.41 years; 312 males) were included. The reduction rate of symptoms at reinfection than that at first infection was significantly higher in the vaccinated group than in the unvaccinated group (p < 0.001). The average reinfection interval was 265.81 days. The interval between the first and second infection was 63.47 days longer in the vaccinated group than in the unvaccinated group. The interval was also 57.23 days, significantly longer in the asymptomatic group than in the symptomatic group (p < 0.001). CONCLUSIONS: Besides its role in preventing severe acute respiratory syndrome coronavirus infection, vaccination reduces the rate of symptomatic reinfection and increases the reinfection interval; thus, it is necessary to be vaccinated even after a previous infection. The findings may inform the decision to avail COVID-19 vaccination.

Population Pharmacokinetics of Levofloxacin and Moxifloxacin, and the Probability of Target Attainment in Ethiopian Patients with Multidrug-Resistant Tuberculosis.

Objective: This study aimed to explore the population pharmacokinetic modeling (PopPK) of levofloxacin (LFX) and moxifloxacin (MXF), as well as the percent probability of target attainment (PTA) as defined by the ratio of the area under the plasma concentration-time curve over 24 h and the in vitro minimum inhibitory concentration (AUC0-24/MIC) in Ethiopian multidrug resistant tuberculosis (MDR-TB) patients. Methods: Steady state-plasma concentration of the drugs in MDR-TB patients were determined using optimized liquid chromatography-tandem mass spectrometry. PopPK and simulations were run at various doses, and pharmacokinetic parameters were estimated. The effect of covariates on the PK parameters and PTA for maximum mycobacterial kill and resistance prevention was also investigated. Results: LFX and MXF both fit in a one-compartment model with adjustments. Serum-creatinine (Cr) influenced (p = 0.01) the clearance of LFX, whereas body mass index (BMI) influenced (p = 0.01) the apparent volume of distribution (V) of MXF. The PTA for LFX maximal mycobacterial kill at the critical MIC of 0.5 mg/L with the simulated 750 mg, 1000 mg, and 1500 mg doses were 29%, 62%, and 95%, respectively, whereas the PTA for resistance prevention at 1500 mg was only 4.8%, with none of the lower doses achieving this target. At the critical MIC of 0.25 mg/L, there was no change in the PTA for maximum bacterial kill when the MXF dose was increased (600 mg, 800 mg, and 1000 mg), but the PTA for resistance prevention was improved. Conclusion: The standard doses of LFX and MXF may not provide adequate drug exposure. PopPK of LFX is more predictable for maximum mycobacterial kill, whereas MXF's resistance prevention target increases with dose. Cr and BMI are likely important covariates for dose optimization in Ethiopian patients.

Reduction in COVID-19 Vaccine Effectiveness against SARS-CoV-2 Variants in Seoul according to Age, Sex, and Symptoms: A Test-Negative Case-Control Study.

BACKGROUND: We evaluated vaccine effectiveness (VE) against infections with SARS-CoV-2 variants of concern in Seoul, the capital of the Republic of Korea, having the highest population density in the country, under real-world conditions. METHODS: We evaluated the reduction in the effectiveness of mRNA and viral-vector COVID-19 vaccines against infection by the SARS-CoV-2 delta variant in a subpopulation from April 2021 to July 2021 who visited screening clinics in Seoul using a test-negative case-control study design. Moreover, we conducted a case-control study matching the ten-year-old age group, sex, healthcare workers, and five districts of Seoul, which are considered confounding factors. RESULTS: The full VE in the pre-delta-dominant period was 95.0% (95% confidence interval [CI]: 91.2-97.2); however, it decreased to 61.1% (95% CI: 53.2-67.6) during the delta-dominant period. Notably, we found that COVID-19 VE was significantly decreased in individuals aged ≥80 years (52.9%, 95% CI: -9.9-79.8), men (50.6 %, 95% CI: 39.4-59.8), and asymptomatic individuals (49.8%, 95% CI: 36.5-60.3) during the widespread SARS-CoV-2 delta variant circulation. CONCLUSIONS: Vaccine-mediated protection drastically declined during the delta-dominant period and in vulnerable groups. This study suggests the requirement for additional countermeasures, such as the administration of a booster vaccine, in vulnerable groups based on age, sex, and symptomatic manifestation.

Epidemiology, Molecular Characteristics, and Virulence Factors of Carbapenem-Resistant Pseudomonas aeruginosa Isolated from Patients with Urinary Tract Infections.

PURPOSE: Pseudomonas aeruginosa is an important pathogen that causes urinary tract infections. Carbapenems are the drugs of choice for the treatment of P. aeruginosa infections. However, the emergence and spread of carbapenem-resistant P. aeruginosa (CRPA) is a serious global health threat. In this study, we investigated the epidemiology, molecular characteristics, drug resistance, and virulence factors of CRPA isolated from urine samples. METHODS: A total of 124 P. aeruginosa isolates were obtained from urine samples collected between March 2020 and February 2021. Clonal relatedness was evaluated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). We performed antimicrobial susceptibility tests and investigated the presence of carbapenemase genes and virulence factors in CRPA isolates. RESULTS: The carbapenem resistance rate of the isolated P. aeruginosa was 46.7% (59/124). A total of 54 (91.5%) out of the 59 CRPA isolates were identified as multidrug-resistant. The majority of the CRPA isolates (81.4%, 48/59) harbored carbapenemase genes, such as bla IMP-6 or bla NDM-1. In an epidemiological analysis using MLST, 88.1% of CRPA isolates were confirmed to be ST773 (50.8%, 30/59) or ST235 (37.3%, 22/59). The CRPA isolates harboring bla IMP-6 and bla NDM-1 belonged to ST235 (PFGE pulsotypes E1-E18, F) and ST773 (PFGE pulsotypes H1-H2, I1-I16) subtypes, respectively. The studied CRPA isolates simultaneously harbored 10 to 14 virulence factors of the 16 virulence factors examined. Nine virulence factor genes (toxA, exoT, plcH, plcN, phzM, phzS, lasB, aprA, and algD) were identified in all CRPA isolates. CONCLUSION: Our study shows that P. aeruginosa ST235 harboring bla IMP-6 and ST773 harboring bla NDM-1-known internationally as high-risk clones with multiple virulence factors-are widely spread in the study area. These findings suggest that continuous monitoring is necessary to prevent the further spread of carbapenemase-producing CRPA.

A 10-gene biosignature of tuberculosis treatment monitoring and treatment outcome prediction.

The clinical utility of blood transcriptomic biosignatures for the treatment monitoring and outcome prediction of tuberculosis (TB) remains limited. In this study, we aimed to discover and validate biomarkers for pulmonary TB treatment monitoring and outcome prediction based on kinetic responses of gene expression during treatment. In particular, differentially expressed genes (DEGs) were identified by time-series comparison. Subsequently, DEGs with the monotonic expression alterations during the treatment were selected. Ten consistently down-regulated genes (CD274, KIF1B, IL15, TLR1, TLR5, FCGR1A, GBP1, NOD2, GBP2, EGF) exhibited significant potential in treatment monitoring, demonstrated via biological and technical validation. Additionally, the biosignature showed potential in predicting the cured versus relapsed patients. Furthermore, the biosignature could be utilized for TB diagnosis, latent tuberculosis infection/active TB differential diagnosis, and risk of progression to active TB. Benchmarking analysis of the 10-gene biosignature with other biosignatures showed equivalent performance in tested data sets. In conclusion, we established a 10-gene transcriptomic biosignature that represents the kinetic responses of TB treatment. Subsequent studies are warranted to validate, refine and translate the biosignature into a precise assay to assist clinical decisions in a broad spectrum of TB management.

Isoniazid Population Pharmacokinetics and Dose Recommendation for Korean Patients With Tuberculosis Based on Target Attainment Analysis.

The wide variability of isoniazid (INH) pharmacokinetics is mainly attributed to the trimodal N-acetyltransferase 2 (NAT2) acetylator phenotype, that is, rapid, intermediate, and slow. Consequently, a uniform INH dose in current clinical practice may lead to treatment failure and emergence of drug resistance. There is a lack of studies on specific doses of INH for different NAT2 acetylator phenotypes among tuberculosis (TB) patients. Therefore, we aimed to provide insight into the optimal dosing of INH for each NAT2 acetylator phenotype with respect to the probability of achieving a pharmacokinetic (PK)/pharmacodynamic target. PK, the NAT2 genotype, and clinical data were collected in a multicenter prospective cohort study conducted at 13 clinical centers in Korea. Population PK modeling and simulation were carried out. Data from 454 TB patients were divided into a training data set and a test data set at a ratio of 4 to 1. The PK of the training data were best described by a 2-compartment model with allometric scaling for body size effect. Importantly, NAT2 acetylator phenotypes significantly affected the apparent clearance. Our model, which provided better predictive performance compared with previously published models, was evaluated by external validation using the test set. The simulation for assessing target efficacy and toxicity indicated that the best INH dosing regimens for Korean tuberculosis patients were once-daily doses of 400, 300, and 200 mg for rapid, intermediate, and slow acetylators, respectively. In conclusion, our study provides a step forward in precision dosing for antituberculosis management.

Molecular epidemiology and mechanisms of tigecycline resistance in carbapenem-resistant Klebsiella pneumoniae isolates.

BACKGROUND: The emergence and transmission of tigecycline- and carbapenem-resistant Klebsiella pneumoniae (TCRKP) have become a major concern to public health globally. Here, we investigated the molecular epidemiology and mechanisms of tigecycline resistance in carbapenem-resistant K pneumoniae (CRKP) isolates. METHODS: Forty-five non-duplicate CRKP isolates were collected from January 2017 to June 2019. We performed antimicrobial susceptibility tests, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). PCR and DNA sequencing were performed for the detection and mutation analysis of acrR, oqxR, ramR, rpsJ, tet(A), and tet(X) genes, which are related to tigecycline resistance. The expression levels of efflux pump genes acrB and oqxB and their regulator genes rarA, ramA, soxS, and marA were assessed by quantitative real-time PCR. RESULTS: The resistance rate to tigecycline in CRKP isolates was 37.8% (17/45). K pneumoniae ST307 was a predominant clone type (70.6%, 12/17) among the TCRKP isolates. The expression levels of acrB (P < .001) and marA (P = .009) were significantly higher in the tigecycline-resistant group than in the tigecycline-intermediate and tigecycline-susceptible groups. Increased expression of acrB was associated with marA expression (r = 0.59, P = .013). CONCLUSIONS: We found that the activated MarA-induced overexpression of AcrAB efflux pump plays an important role in the emergence of tigecycline resistance in CRKP isolates.

Predicting inadequate treatment response in children with chronic spontaneous urticaria.

BACKGROUND: We aimed to investigate the treatment response and associated factors for loss of control in children with chronic spontaneous urticaria (CSU). METHODS: A total of 240 CSU patients (aged 0-17 years) were enrolled in a single-center study in Korea from May 2014 to May 2019. We retrospectively reviewed the medical records and compared the duration of treatment and step of medications using the urticaria control test (UCT, range 0-16 points). Serum total immunoglobulin levels, eosinophil count, allergic sensitization, autologous serum skin test, antinuclear antibody, thyroid function test, erythrocyte sedimentation rate, and C-reactive protein were measured. The patients were divided into well-controlled (sustained UCT ≥12), partly controlled (fluctuating UCT around 12), and poorly controlled (sustained UCT <12) groups. RESULTS: Of the 240 children, 150 (62.5%) achieved well-controlled status; 74 (30.8%), partly controlled; and 16 (6.7%), poorly controlled. Longer duration (adjusted odds ratio: 1.09, 95% confidence interval: 1.05-1.13, P < .001) and higher treatment steps (5.61, 2.82-11.14, P < .001) for reaching the initial 12 points or more of UCT score, initial urticaria activity score (UAS) score (1.06, 1.03-1.09, P < .001), and food sensitization (1.88, 1.03-3.46, P = .041) were associated with inadequate treatment response. The mean duration to symptom free for 1 month without medication was 14.6 months in the well-controlled group and 22.1 months in the partly controlled group (P = .002). CONCLUSION: Children with CSU have a good treatment response. Longer duration and higher treatment step until the initial disease control, higher initial UAS7 score, and food sensitization can predict inadequate treatment response.

Changes of frequency and expression level of CD161 in CD8+ T cells and natural killer T cells in peripheral blood of patients with systemic lupus erythematosus.

Immunologic abnormalities of natural killer (NK) cells and T cells play a role in the pathogenesis of systemic lupus erythematosus (SLE). CD161 is expressed on most of the NK cells and on some T cells. The quantities of CD161-expressing cells and expression levels of CD161 were analyzed in T cells and NK cells from patients with SLE compared with normal controls. The expression of CD161 on NK cells, NKT cells, CD4+ T cells, and CD8+ T cells in peripheral blood from patients with inactive SLE and active SLE, and from the normal controls group were determined using flow cytometry. The frequency and expression level of CD161 in the lymphocyte subsets and its relationship with the quantity of regulatory T cells, anti-double stranded DNA antibody, and the titer of antinuclear antibody were evaluated. Both the percentages of the CD161+ subpopulation and the mean fluorescence intensities (MFIs) of CD161 in CD8+ T cells and NKT cells decreased significantly in SLE patients compared with normal controls (P < .001). The CD161 expression in CD8+ T cells and NKT cells also decreased in the anti-dsDNA (+) group (P < .05). The counts of Treg cells were lower in SLE patients and were weakly correlated with the percentage of the CD161 subpopulation (r = 0.229, P = .016) and the MFIs of CD161 expression in CD8+ T cells (r = .232, P = .014). The frequencies and levels of CD161 expression on CD8+ T cells and NKT cells were reduced in SLE patients, suggesting that an abnormality of these cells was related to the pathogenesis of SLE.

Emergence and transmission of New Delhi metallo-beta-lactamase-5-producing Escherichia coli Sequence Type 361 in a Tertiary Hospital in South Korea.

BACKGROUND: The emergence of carbapenem-resistant Escherichia coli (E coli) is a serious global health threat, but little is known about carbapenemase-producing E coli in Daejeon, South Korea. The aim of this study was to investigate characteristics of thirteen carbapenem-resistant E coli isolates in a tertiary hospital. METHODS: Thirteen non-duplicate carbapenem-resistant E coli strains were collected from October 2017 to January 2018. Antimicrobial susceptibility was determined with the E test or disk diffusion method. The carbapenem minimum inhibitory concentrations (MICs) were determined by the agar dilution method. The colistin and tigecycline MICs were determined by broth microdilution. The resistance genes, including carbapenemase genes, were evaluated by polymerase chain reaction, and DNA sequencing was performed to characterize the genes. Pulsed-field gel electrophoresis and multilocus sequence typing (MLST) were performed to evaluate the clonal relatedness of isolates. The clinical data of patients were retrospectively reviewed. RESULTS: All the E coli isolates harbored blaNDM-5 gene and were resistant to most of the antimicrobial agents, such as carbapenem, cephalosporins, ciprofloxacin, and chloramphenicol, excluding amikacin and colistin. Other resistant genes, such as blaTEM-1 , blaCTX-M-15 , blaCMY-2 , aac(6')-Ib-cr, and qepA, were detected. The E coli isolates harboring blaNDM-5 belonged to ST361 (n = 11), ST12 (n = 1), ST410 (n = 1), and PFGE types A (n = 11), B (n = 1), and C (n = 1). CONCLUSIONS: This study reports on an outbreak of a predominant epidemic clone, the NDM-5 producing, multidrug-resistant E coli ST361 isolate. These findings suggest that we should pay attention to infection control measures to limit the spread of NDM-5-producing pathogens.

Comparison of the Genedia MTB/NTM Detection Kit and Anyplex plus MTB/NTM Detection Kit for detection of Mycobacterium tuberculosis complex and nontuberculous mycobacteria in clinical specimens.

BACKGROUND: Real-time (RT) PCR is a rapid and accurate method that is widely used for the detection of Mycobacterium tuberculosis complex (MTB). The aim of this study was to evaluate and compare the performance of the Genedia MTB/NTM Detection Kit and the Anyplex plus MTB/NTM Detection kit in the detection of MTB and nontuberculous mycobacteria (NTM) in clinical specimens. METHODS: From October 2017 to February 2018, 236 respiratory specimens and 137 non-respiratory specimens, from patients with suspected tuberculosis, were examined. AFB smear, culture, and RT-PCR using the Genedia MTB/NTM Detection kit (Green Cross Medical Science Corp.) and the Anyplex plus MTB/NTM Detection kit (Seegene) were applied. PCR performance in the detection of MTB and NTM was evaluated in relation to culture results and between the two assays. RESULTS: Culture was positive for MTB in 30 (8.0%) of the 373 specimens and for NTM in 23 (6.2%). The sensitivity and specificity of MTB detection with the Genedia kit were 76.7% and 99.7%, respectively, whereas the Anyplex kit sensitivity and specificity for MTB detection were 86.7% and 97.5%, respectively. Both kits exhibited the same sensitivity (73.9%) for NTM detection, and the specificity was 100% and 99.4% for the Genedia and Anyplex kits, respectively. CONCLUSIONS: The Genedia and Anyplex kits demonstrated high sensitivity and specificity for the detection of MTB and NTM. Both kits have a high concordance rate and can be used more widely in clinical laboratories for the early detection of tuberculosis.

Inhibition of CorA-Dependent Magnesium Homeostasis Is Cidal in Mycobacterium tuberculosis.

Mechanisms of magnesium homeostasis in Mycobacterium tuberculosis are poorly understood. Here, we describe the characterization of a pyrimidinetrione amide scaffold that disrupts magnesium homeostasis in the pathogen by direct binding to the CorA Mg2+/Co2+ transporter. Mutations in domains of CorA that are predicted to regulate the pore opening in response to Mg2+ ions conferred resistance to this scaffold. The pyrimidinetrione amides were cidal against the pathogen under both actively replicating and nonreplicating conditions in vitro and were efficacious against the organism during macrophage infection. However, the compound lacked efficacy in infected mice, possibly due to limited exposure. Our results indicate that inhibition of Mg2+ homeostasis by CorA is an attractive target for tuberculosis drug discovery and encourage identification of improved CorA inhibitors.

Cytogenetic evolution in myeloproliferative neoplasms with different molecular abnormalities.

We investigated the changes in chromosomal abnormalities in myeloproliferative neoplasm (MPN) patients during long-term follow-up. In total, 28 MPN patients (22 with primary myelofibrosis and 6 with polycythemia vera) were included. Among them, 25 patients underwent serial bone marrow (BM) biopsies during disease progression, and 3 patients had cytogenetic abnormalities at initial diagnosis but lacked follow-up BM biopsies. JAK2, CALR, and MPL mutation analyses were performed. Targeted sequencing analysis was conducted in 11 patients. Among the 28 patients, 21 (75.0%) had cytogenetic abnormalities either at diagnosis (8/26) or during follow-up. The median time from the initial analysis to the appearance of additional cytogenetic abnormalities was 8.4 years. Among the chromosomal abnormalities at initial diagnosis, trisomy 8 (3/26, 11.5%) was the most frequent, followed by gain of 1q, del(20q), and del(9q) (each in 2/26). Among all chromosomal abnormalities, including those that occurred during follow-up, the most frequent was del(20q) and +1q (8/28, 28.6%), followed by del(6p) (14.3%) and trisomy 8 (10.7%). Del(20q) was more frequent in CALR-mutated patients (4/6, 66.7%) than in JAK2-mutated patients (3/19, 15.8%, P = 0.016). The presence of cytogenetic abnormalities at initial diagnosis was associated with poor prognosis. Cytogenetic evolution may provide interesting insights into the disease course.

Automated Versus Conventional Microscopic Interpretation of Antinuclear Antibody Indirect Immunofluorescence Test.

BACKGROUND: The detection of antinuclear antibodies (ANAs) is crucial for the diagnosis of systemic autoimmune rheumatic diseases. Here, we evaluated the performance of an automated ANA image analyzer, EUROPattern Suite. METHODS: We compared the automated and manually revised interpretations of EUROPattern Suite with conventional microscopic interpretations of indirect immunofluorescence (IIF) by calculating the analytical sensitivity and specificity for ANA detection and evaluating the concordance between these approaches for ANA detection, pattern recognition, and titer determination. RESULTS: The analytical sensitivity and specificity of EUROPattern Suite for ANA detection were 97.7% and 88.2%, respectively, relative to those of conventional IIF, with a concordance of 94.4% 3κ=0.874). After manual revision, the analytical sensitivity, specificity, and concordance improved to 98.5%, 94.1%, and 97.0% (κ=0.932), respectively. The concordance rates for pattern recognition with simple and mixed patterns were 72.1% and 56.0%, respectively, and varied depending on the type of pattern. After manual revision, the concordance rates with simple and mixed patterns increased to 97.1% and 84.0%, respectively. The concordance rate for titer determination with a simple pattern was 84.6%. CONCLUSION: Although automated pattern recognition has some limitations, EUROPattern Suite facilitates automated ANA detection with a high sensitivity and concordance with conventional IIF.

Structures of DPAGT1 Explain Glycosylation Disease Mechanisms and Advance TB Antibiotic Design.

Protein N-glycosylation is a widespread post-translational modification. The first committed step in this process is catalysed by dolichyl-phosphate N-acetylglucosamine-phosphotransferase DPAGT1 (GPT/E.C. 2.7.8.15). Missense DPAGT1 variants cause congenital myasthenic syndrome and disorders of glycosylation. In addition, naturally-occurring bactericidal nucleoside analogues such as tunicamycin are toxic to eukaryotes due to DPAGT1 inhibition, preventing their clinical use. Our structures of DPAGT1 with the substrate UDP-GlcNAc and tunicamycin reveal substrate binding modes, suggest a mechanism of catalysis, provide an understanding of how mutations modulate activity (thus causing disease) and allow design of non-toxic "lipid-altered" tunicamycins. The structure-tuned activity of these analogues against several bacterial targets allowed the design of potent antibiotics for Mycobacterium tuberculosis, enabling treatment in vitro, in cellulo and in vivo, providing a promising new class of antimicrobial drug.

The prognostic impact of lymphocyte subsets in newly diagnosed acute myeloid leukemia.

BACKGROUND: Tumor-infiltrating lymphocytes, which form a part of the host immune system, affect the development and progression of cancer. This study investigated whether subsets of lymphocytes reflecting host-tumor immunologic interactions are related to the prognosis of patients with acute myeloid leukemia (AML). METHODS: Lymphocyte subsets in the peripheral blood of 88 patients who were newly diagnosed with AML were analyzed by quantitative flow cytometry. The relationships of lymphocyte subsets with AML subtypes, genetic risk, and clinical courses were analyzed. RESULTS: The percentages of T and NK cells differed between patients with acute promyelocytic leukemia (APL) and those with AML with myelodysplasia-related changes. In non-APL, a high proportion of NK cells (>16.6%) was associated with a higher rate of death before remission (P=0.0438), whereas a low proportion of NK cells (≤9.4%) was associated with higher rates of adverse genetic abnormalities (P=0.0244) and relapse (P=0.0567). A multivariate analysis showed that the lymphocyte subsets were not independent predictors of survival. CONCLUSION: Lymphocyte subsets at diagnosis differ between patients with different specific subtypes of AML. A low proportion of NK cells is associated with adverse genetic abnormalities, whereas a high proportion is related to death before remission. However, the proportion of NK cells may not show independent correlations with survival.

Discovery and Structure-Activity-Relationship Study of N-Alkyl-5-hydroxypyrimidinone Carboxamides as Novel Antitubercular Agents Targeting Decaprenylphosphoryl-ß-d-ribose 2'-Oxidase.

Magnesium plays an important role in infection with Mycobacterium tuberculosis ( Mtb) as a signal of the extracellular environment, as a cofactor for many enzymes, and as a structural element in important macromolecules. Raltegravir, an antiretroviral drug that inhibits HIV-1 integrase is known to derive its potency from selective sequestration of active-site magnesium ions in addition to binding to a hydrophobic pocket. In order to determine if essential Mtb-related phosphoryl transfers could be disrupted in a similar manner, a directed screen of known molecules with integrase inhibitor-like pharmacophores ( N-alkyl-5-hydroxypyrimidinone carboxamides) was performed. Initial hits afforded compounds with low-micromolar potency against Mtb, acceptable cytotoxicity and PK characteristics, and robust SAR. Elucidation of the target of these compounds revealed that they lacked magnesium dependence and instead disappointingly inhibited a known promiscuous target in Mtb, decaprenylphosphoryl-ß-d-ribose 2'-oxidase (DprE1, Rv3790).

Association between Biofilm Formation and Antimicrobial Resistance in Carbapenem-Resistant Pseudomonas Aeruginosa.

Recently, carbapenem resistance in P. aeruginosa is an increasingly important problem globally. Biofilm formation is a well-known pathogenic mechanism of P. aeruginosa, and the gene, pslA, plays an important role in its primary stages. We studied the association between biofilm formation and pslA in carbapenem-resistant P. aeruginosa isolates, along with antimicrobial resistance and the prevalence of metallo-ß-lactamase (MBL) genes, based on the presence of pslA 82 carbapenem-resistant P. aeruginosa isolates were collected from a tertiary hospital in Daejeon, Korea, between March 2008 and June 2014. Minimum inhibitory concentrations (MICs) of nine antimicrobial agents were determined using the agar dilution method. Biofilm formation was measured by microtiter plate assay. PCR and sequencing were used to identify pslA and the MBL gene. 76 (92.7%) carbapenem-resistant isolates were biofilm producers. These biofilm producers showed higher levels of amikacin, ceftazidime, and cefepime resistance than non-producers. pslA was detected in 71 (93.4%) biofilm-producing isolates and these results were statically significant (p<0.01). 11 isolates carrying pslA and blaIMP-6 were extremely resistant to all antimicrobials tested. In this study, biofilm formation was significantly associated with pslA Furthermore, the coexistence of pslA and the MBL gene in carbapenem-resistant isolates likely contributed to the increase in antimicrobial resistance.

Rapid Screening of Urinary Tract Infection and Discrimination of Gram-Positive and Gram-Negative Bacteria by Automated Flow Cytometric Analysis Using Sysmex UF-5000.

Rapid screening of urinary tract infection is important to determine antibiotic treatment and reduce unnecessary urine culture. We evaluated the performance of the new flow cytometry-based UF-5000 automated urine analyzer (Sysmex, Kobe, Japan). A total of 1,430 urine samples from 1,226 patients were analyzed and compared to urine cultures to which a Previ Isola (bioMérieux, Marcy l'Etoile, France) system was applied. In total, 878 of 1,430 urine cultures (61.4%) produced ≥103 CFU/ml bacterial growth (309 with Gram-negative [GN] bacteria, 517 with Gram-positive [GP] bacteria, and 52 mixed cultures), with 336 samples (23.5%) presenting ≥105 CFU/ml bacterial growth. The ≥105 CFU/ml bacterial growth was detected by a ≥71 bacteria/µl UF-5000 bacterial count with 95% sensitivity and 84% specificity. Using a cutoff of <15 bacteria/µl to determine whether or not to culture, 50.9% of samples were below the cutoff, 94.8 and 99.5% of which presented <104 and <105 CFU/ml of bacterial growth, respectively. The bacterial discrimination performance of the UF-5000 for GN bacteria was superior to that for GP bacteria, and in ≥105 CFU/ml monobacterial samples, the sensitivity and specificity for reporting GN bacteria were 91.7 and 90.0%, respectively. In summary, UF-5000 demonstrated potential utility for the rapid screening of negative bacterial cultures. However, this utility is dependent on the patient population; cutoff optimizations must be performed for specific populations. In addition, UF-5000 presented improved performance in characterizing GP and GN bacteria, although the concurrence rates were not high enough to replace routine cultures.