Seung Hwan Oh

Two Cases of Peritonitis Caused by Kocuria marina in Patients Undergoing Continuous Ambulatory Peritoneal Dialysis

ABSTRACT Kocuria spp. are members of the Micrococcaceae family that are frequently found in the environment and on human skin. Few human infections have been reported. We describe what appear to be the first two cases of Kocuria marina peritonitis in patients undergoing continuous ambulatory peritoneal dialysis.

IDENTIFICATION OF COAGULASE-NEGATIVE STAPHYLOCOCCI ISOLATED FROM CONTINUOUS AMBULATORY PERITONEAL DIALYSIS FLUID USING 16S RIBOSOMAL RNA, tuf, AND SodA GENE SEQUENCING

♦ 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.

Tetraploid acute promyelocytic leukemia with double t(15;17) and PML/RARA rearrangements detected by fluorescence in situ hybridization analysis

Acute promyelocytic leukemia (APL) is characterized by a serious hemorrhagic syndrome, unique morphologic findings, and its response to retinoids. Tetraploidy is a very rare chromosomal abnormality in acute myelocytic leukemia. This report presents a unique case of APL with a tetraploid clone characterized by two t(15;17) without other chromosomal changes, as well as PML/RARA rearrangements confirmed fluorescence in situ hybridization. The morphology of the blast cells was that of the classic M3 subtype, but the mean blast size exceeded that of control APL cases with diploidy. A chromosomal study revealed a 92,XXXX,t(15;17)(q22;q21)x2 karyotype in all 20 metaphase spreads. Despite all-trans-retinoic acid (ATRA) treatment and chemotherapy, leukemic cells persisted in the blood, and the patient died of an intracranial hemorrhage on the 16th day after admission.

Serial changes in serum procalcitonin, interleukin 6, and C-reactive protein levels according to non-specific surgical stimulation.

Abstract Background: The aim of this study is to investigate useful perioperative monitoring markers by comparing serial levels of serum procalcitonin (PCT), interleukin 6 (IL-6), and C-reactive protein (CRP) in routine surgical circumstances. Methods: In 285 surgeries of 277 patients, blood samples were obtained serially, at least three times per patient: within 48 h before surgery, 0–6 h after surgery (post-OP1), >6–28 h after surgery (post-OP2), and/or later (post-OP3). PCT, IL-6, and CRP were measured. Their demographic, operative, laboratory, and clinical data were collected retrospectively. Results: The systemic inflammatory response syndrome (SIRS) (n=39) and sepsis (n=11) groups showed higher post-operative values than the non-SIRS group (n=233). Their maximum significant median levels were 8.96 vs. 0.21 μg/L for post-OP2 PCT, 743.1 vs. 85.8 ng/L for post-OP1 IL-6, and 103.4 vs. 49.0 mg/L for post-OP2 CRP. Among non-SIRS patients, 12 patients developed undesirable post-operative events, including secondary surgery and death. The highest area under receiver operator characteristic curves was 0.92 at post-OP1 PCT (cut-off, 0.1 μg/L; sensitivity, 91.7%; specificity, 78.7%), and the next highest was 0.84 at post-OP1 IL-6 (cut-off, 359 ng/L; sensitivity, 66.7%; specificity, 91.9%). All biomarkers were increased by non-specific surgical stimuli; however, post-OP1/post-OP2 PCT were <1.0 μg/L (90th percentile) except major abdominal surgeries. Conclusions: Post-OP1 PCT measurement may be useful as a post-operative monitoring marker for the following reasons: pre-operative values less than the cut-off regardless of pre-operative state (age, malignancy, and American Society of Anesthesiologists class); minimal influence from surgical stimulus; and prediction of post-operative undesirable events.

Reduction of Contamination of Mycobacterial Growth Indicator Tubes with a Modified Antimicrobial Combination

ABSTRACT Culture in the fluorimetric Mycobacteria Growth Indicator Tube (MGIT) treated with a combination of vancomycin, amphotericin B, and nalidixic acid (VAN) showed growth of most strains of 31 mycobacterial species with a less-than-1-day delay. The results were similar to those in the MGIT with polymyxin B, amphotericin B, nalidixic acid, trimethoprim, and azlocillin, but with respiratory specimens, the MGIT with VAN showed a lower contamination rate with no change in the detection rate or time.

Incidence and Prognostic Impact of DNMT3A Mutations in Korean Normal Karyotype Acute Myeloid Leukemia Patients

Background. DNA methyltransferase 3A (DNMT3A) mutation was recently introduced as a prognostic indicator in normal karyotype (NK) AML and we evaluated the incidence and prognostic impact of DNMT3A mutations in Korean NK AML patients. Methods. Total 67 NK AML patients diagnosed during the recent 10 years were enrolled. DNMT3A mutations were analyzed by direct sequencing and categorized into nonsynonymous variations (NSV), deleterious mutations (DM), and R882 mutation based on in silico analysis results. Clinical features and prognosis were compared with respect to DNMT3A mutation status. Results. Three novel (I158M, K219V, and E177V) and two known (R736H and R882H) NSVs were identified and the latter three were predicted as DMs. DNMT3A NSVs, DMs, and R882 mutation were identified in 14.9%–17.9%, 10.3%–10.4%, and 7.5% of patients, respectively. DNMT3A mutations were frequently detected in FLT3 ITD mutated patients (P = 0.054, 0.071, and 0.071 in NSV, DMs, and R882 mutation, resp.) but did not affect clinical features and prognosis significantly. Conclusions. Incidences of DNMT3A NSVs, DMs, and R882 mutation are 14.9%–17.9%, 10.3%–10.4%, and 7.5%, respectively, in Korean NK AML patients. DNMT3A mutations are associated with FLT3 ITD mutations but do not affect clinical outcome significantly in Korean NK AML patients.

Comparison of Anti-mycobacterial Drug Susceptibility Test Results by Institutes and Methods

Background: The purposes of the current study were to evaluate the concordant rates of anti-mycobacterial drug susceptibility test (DST) results in different solid media performed in different institutes, and to determine reliable susceptible testing methods. Methods: One hundred and twenty two Mycobacterium tuberculosis strains were isolated from patients in A Hospital in 2005. DSTs were performed by the absolute concentration method using Lowenstein Jensen medium in both A Hospital (method A-1) and B Institute (method B-1) and by the proportion method using Middlebrook 7H10 agar in B Institute (method B-2). Nine drugs were used including isoniazid and rifampin. Sensitivity and specificity of each method were estimated by using the acceptable standard of 90% for isoniazid and rifampin and 80% for other drugs. The therapeutic outcomes of quinolone-administered patients were evaluated according to ofloxacin susceptibility results. Results: Method B-1 showed sensitivity and specificity levels over the acceptable standard levels for all drugs. Method B-2 showed specificity lower than the acceptable levels for rifampin and cycloserine. Method A-1 showed specificity lower than the acceptable levels for isoniazid, streptomycin, p-aminosalicylic acid, and ofloxacin and sensitivity lower than the acceptable levels for prothionamide and cycloserine. The concordance rates of therapeutic outcomes with method B-1, method B-2, and method A-1 were 77%, 74%, and 65%, respectively. Conclusion: The drug susceptibility results for some drugs were discordant between the testing laboratories and media, requiring an urgent application of quality control programs to raise the reliability of anti-mycobacterial DST. (Korean J Clin Microbiol 2008; 11:43-48)

Acute Myeloid Leukemia with t(2;6)(q12;q12) Reveals Dysmegakaryopoietic Finding and Poor Prognosis

We present a case of acute myeloid leukemia (AML) with a balanced translocation between chromosomes 2q12 and 6q12, t(2;6)(q12;q12). This abnormality was defined by conventional cytogenetics and multicolor banding techniques using specific probes for chromosome 2. Blasts accounted for 2% of white blood cells in peripheral blood and approximately 30% of all nucleated cells in marrow aspirates. They were medium-to-large cells with fine nuclear chromatin, indistinct nucleoli and basophilic cytoplasm. Immunophenotyping indicated the blasts were of myeloid lineage with aberrant CD7 expression. Therefore, the patient was diagnosed as ‘Acute myeloid leukemia, NOS, AML with maturation’ according to the WHO classifications. In literature review, this case should be considered as the first report of AML with t(2;6)(q12;q12). Interestingly, a bone marrow smear showed dysmegakaryopoietic findings, such as multinucleated or mononucleated megakaryocytes and micromegakaryocytes. After diagnosis, the induction chemotherapy was given with idarubicin and cytosine arabinoside according to the protocol of intermediate-prognostic AML. After chemotherapy, the patient had been in remission for 13 months but relapsed with 54% blasts in marrow aspirates. The cytogenetic analysis revealed t(2;6)(q12;q12), which is same with karyotype shown at diagnosis. In this case report, the pathologic and clinical findings of AML with t(2;6)(q12;q12) were described, which are severe dysmegakaryopoiesis and poor prognosis. This report may be helpful for clinician to have a similar case treated