Ji Hyun Cho

High prevalence of ceftazidime-resistant Klebsiella pneumoniae and increase of imipenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. in Korea: a KONSAR program in 2004.

A nationwide antimicrobial resistance surveillance has been conducted since 1997 in Korea. In this study, susceptibility test data generated in 2004 by KONSAR group hospitals were analyzed and compared to those at a commercial laboratory. In hospitals, the rank orders of organisms in 2004 were identical to those in 2003. The most prevalent species was Staphylococcus aureus (20.2%) in hospitals, but Escherichia coli (29.7%) in the commercial laboratory. The proportions of Enterococcus faecium to all isolates of Enterococcus faecalis plus E. faecium were 47.2% in hospitals and 24.9% in the commercial laboratory. The mean resistance rates of significant antimicrobial-organism combinations in hospitals were: oxacillin-resistant S. aureus (68%), oxacillin-resistant (penicillin-nonsusceptible) Streptococcus pneumoniae (68%), vancomycin-resistant E. faecium (25%), cefotaxime-resistant E. coli (14%), ceftazidime- and cefoxitin-resistant Klebsiella pneumoniae (34% and 32%, respectively), and imipenem-resistant Acinetobacter spp. and Pseudomonas aeruginosa (17% and 24%, respectively). In conclusion, oxacillin-resistant staphylococci, expanded-spectrum cephalosporin-resistant K. pneumoniae, and imipenem-resistant Acinetobacter spp. and P. aeruginosa were prevalent in 2004. Increasing trends were observed for vancomycin-resistant E. faecium, cefoxitin-resistant E. coli and K. pneumoniae, and imipenem-resistant Acinetobacter spp. and P. aeruginosa. Certain antimicrobial-organism combinations were also prevalent among the commercial laboratory-tested strains.

Comprehensive analysis of blood culture performed at nine university hospitals in Korea.

Background Optimal blood culture performance is critical for successful diagnosis and treatment of sepsis. To understand the status 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.

Characteristics of Microorganisms Isolated from Blood Cultures at Nine University Hospitals in Korea during 2009

Department of Laboratory Medicine & Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Department of Laboratory Medicine, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Department of Laboratory Medicine, Paik Institute for Clinical Research, Inje University College of Medicine, Busan, Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul National University Hospital, Seoul, College of Medicine, Chungnam National University, Daejeon, School of Medicine, Keimyung University, Daegu, Hallym University College of Medicine, Seoul, College of Medicine, Wonkwang University, Iksan, Korea

Association between Elevated Pleural Interleukin-33 Levels and Tuberculous Pleurisy

Background Interferon-γ (IFN-γ) plays a crucial role in Mycobacterium tuberculosis induced pleural responses. Interleukin (IL)-33 up-regulates the production of IFN-γ. We aimed to identify whether an association between pleural IL-33 levels and tuberculous pleurisy exists and determine its diagnostic value. Methods Pleural IL-33, ST2 (a receptor of IL-33), adenosine deaminase (ADA), and IFN-γ, as well as serum IL-33 and ST2 were measured in 220 patients with pleural effusions (PEs). Patients with malignant (MPEs), parapneumonic (PPEs), tuberculous (TPEs), and cardiogenic (CPEs) pleural effusions were included. Results Pleural and serum IL-33 levels were highest or tended to be higher in patients with TPEs than in those with other types of PEs. The median pleural fluid-to-serum IL-33 ratio was higher in TPE cases (≥ 0.91) than in other PE cases (≤ 0.56). Pleural IL-33 levels correlated with those of pleural ADA and IFN-γ. However, the diagnostic accuracies of pleural IL-33 (0.74) and pleural fluid-to-serum IL-33 ratio (0.75) were lower than that of ADA (0.95) or IFN-γ (0.97). Pleural ST2 levels in patients with MPEs were higher than in patients with TPEs. Serum ST2 levels did not differ among the groups. Conclusions We identified an association between elevated pleural IL-33 levels and tuberculous pleurisy. However, we recommend conventional pleural markers (ADA or IFN-γ) as diagnostic markers of TPE.

Increasing prevalence of blaOXA-23-carrying Acinetobacter baumannii and the emergence of blaOXA-182-carrying Acinetobacter nosocomialis in Korea.

Carbapenem-resistant Acinetobacter spp. have been increasingly reported worldwide with the production of OXA-type carbapenemases as the main mechanism of carbapenem resistance. The prevalent bla(OXA) genes are known to vary significantly depending on time and place of isolation. We investigated the prevalence of bla(OXA) genes by PCR in Acinetobacter spp. isolated in Korea. Among a total of 336 isolates collected from Hospital A from 2002 to 2011, the overall proportion of bla(OXA)-23-like, ISAba1-associated bla(OXA-51)-like, and bla(OXA-182) genes were 44.0%, 49.7%, and 5.1%, respectively. The bla(OXA-58)-like gene was detected in only 1 isolate. A drastic increase in Acinetobacter isolates with bla(OXA-23)-like genes and a decrease in isolates harboring ISAba1-associated bla(OXA-51)-like genes have been observed since the mid-2000s. The bla(OXA-23)-like genes were detected in all carbapenem-nonsusceptible isolates collected in 2011 from 9 hospitals. The OXA-182, which belongs to the fifth group of OXA-type carbapenemase, was detected in Acinetobacter baumannii isolates recovered as early as 2002. It is worrisome results that bla(OXA-182)-carrying Acinetobacter nosocomialis has emerged and caused outbreaks of infection.

Nucleotide changes related to hepatocellular carcinoma in the enhancer 1/x-promoter of hepatitis B virus subgenotype C2 in cirrhotic patients

Hepatocellular carcinoma (HCC) is widely known to develop more frequently in cirrhotic patients with a high expression of Hepatitis B virus X protein (HBx), which is controlled by the enhancer 1 (Enh1)/X‐promoter. To examine the effect of the mutations in the Enh1/X‐promoter region in hepatitis B virus (HBV) genomes on the development of HCC, we investigated the differences in HBV isolated from cirrhotic patients with or without HCC along with the promoter activities of certain specific mutations within the Enh1/X‐promoter. We examined 160 hepatitis B surface antigen (HBsAg)‐positive cirrhotic patients (80 HCC patients, 80 non‐HCC patients) by evaluating the biochemical, virological, and molecular characteristics. We evaluated the functional differences in certain specific mutations within the Enh1/X‐promoter. The isolated sequences included all of the subgenotypes C2. The sites that showed higher mutation rates in the HCC group were G1053A and G1229A, which were found to be independent risk factors through multiple logistic analysis (Pu2003<u20030.05). Their promoter activities were elevated 2.38‐ and 4.68‐fold, respectively, over that of the wild type in the HepG2 cells. Similarly, both the mRNA and protein levels of HBx in these two mutants were much higher than that in wild type‐transfected HepG2 cells. Mutated nucleotides of the Enh1/X‐promoter, especially G1053A and G1229A mutations in the HBV subgenotype C2 of patients with cirrhosis, can be risk factors for hepatocarcinogenesis, and this might be due to an increase in the HBx levels through the transactivation of the Enh1/X‐promoter. (Cancer Sci 2010)

Incidence and Type of Monoclonal or Biclonal Gammopathies in Scrub Typhus

BACKGROUNDnKorea is an endemic area of scrub typhus and it is a common seasonal febrile illness. Although, various humoral immune responses to scrub typhus have been documented, no association between gammopathy and scrub typhus has ever been reported. We analyzed the incidences and types of monoclonal and biclonal gammopathies in scrub typhus for better coping with those gammopathies in scrub typhus.nnnMETHODSnAnti-Orientia tsutsugamushi antibody-positive sera identified by indirect immunofluorescence assay were acquired from 40 patients with confirmed scrub typhus. Monoclonal and biclonal gammopathies were screened by protein electrophoresis and were confirmed using immunofixation electrophoresis (IFE). Laboratory findings on admission of the patients with monoclonal or biclonal gammopathy were investigated retrospectively to characterize the gammopathies.nnnRESULTSnMonoclonal or biclonal gammopathies were detected in 30% (12/40) of patients with scrub typhus (IgG-lambda, 40%; IgG-kappa, 30%; IgM-kappa, 10%; IgM-lambda, 10%; IgA-kappa, 5%; IgA-lambda, 5%). Concentrations of clonal immunoglobulin were less than 3 g/dL in all gammopathies, and hypercalcemia was not detected in any of the patients.nnnCONCLUSIONSnOur results suggest possible association between gammopathies and scrub typhus. Further studies in larger series will be needed for exact incidence and clinical course of gammopathies in scrub typhus.

Prevalence and spread of integron-IS26 in imipenem-resistant Acinetobacter baumannii clinical isolates in South Korea

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Evaluation of Direct Immunofluorescence Test with PCR for Detection of Novel Influenza A (H1N1) Virus during 2009 Pandemic

During the 2009 novel influenza (H1N1) pandemic, the sensitivity of direct immunofluorescence assay (DFA) for H1N1 infection was 62% (266/429) of that of the polymerase chain reaction (PCR) test. The sensitivity of the DFA differed significantly with the age of patients: the sensitivity was the highest (71.8%) for patients aged <10 years and the lowest for patients aged ≥30 years. The sensitivity of DFA in patients aged ≥30 years was 40.7%. Furthermore, the sensitivity (67.3%, 171/254) of DFA was higher for patients who had a high temperature at admission. An increase in the incidence of H1N1 infection did not influence the sensitivity of DFA (62.1% vs. 62%; p=0.984) test, but resulted in a decrease in the negative predictive value, from 92.4% (700/757) to 69.6% (247/355). PCR may be useful as the initial test for diagnosing H1N1 infection in patients aged ≥30 years with a normal temperature at presentation.

Detection of Respiratory Viruses in Children by Multiplex Reverse Transcriptase PCR, Direct Immunofluorescence Assay, and Shell Vial Culture

Background: Direct immunofluorescence assay (DFA) and shell vial culture (SVC) have been used to diagnose respiratory viral infections. Recently a multiplex reverse transcriptase PCR (mRT-PCR) for 12 respiratory viruses has been introduced. We evaluated the diagnostic usefulness of these methods. Methods: Among 275 nasopharyngeal aspirates (NPAs) received from pediatric patients during the 3-month period from May through July, 2007, 122 samples were selected so as to include diverse viruses and varying numbers of DFA-positive cells for mRT-PCR. Also, the results of the 85 NPAs that had been analyzed by both DFA and SVC were reviewed retrospectively. Results: Detection rates for the seven major respiratory viruses, respiratory syncytial virus (RSV), influenza virus A and B, parainfluenza virus 1, 2, and 3, and adenovirus by DFA vs mRT-PCR were 32.0% and 55.7%, and by DFA vs SVC were 32.9% and 40.0%. A number of adenovirus detected by DFA vs mRT-PCR were 12 and 22, and by DFA vs SVC were 6 and 18. A number of RSV detected were 3 and 6, and 13 and 8, respectively. Conclusion: mRT-PCR detected the respiratory viruses at the highest rate, followed by SVC and DFA in a decreasing order. However, DFA and multiplex PCR were more sensitive than SVC for RSV, while SVC was more sensitive than the other methods for adenovirus. (Korean J Clin Microbiol 2009;12:110115)