Jungok Kim

Mesenchymal progenitor cells in the human umbilical cord.

Mesenchymal progenitor or stem cells (MPCs) isolated from fetal blood, liver, and bone marrow are a population of multipotential cells that can proliferate and differentiate into multiple mesodermal tissues including bone, cartilage, muscle, ligament, tendon, fat, and stroma. The objective of this study was to isolate and characterize MPCs in the human umbilical cord. The suspensions of endothelial and subendothelial cells in cord vein were collected and cultured in M199 supplemented with 10% fetal bovine serum (FBS). Of 50 umbilical cord samples, 3 had numerous fibroblastoid cells morphologically distinguishable from endothelial cells. Fibroblastic cells displayed lack of expression of vWF, Flk-1, and PECAM-1, indicating the endothelial cell-specific marker. To investigate the differentiation potentials, the cells were cultured in adipogenic or osteogenic medium for 2 weeks. Fibroblast-like cells treated with adipogenic supplementation showed Oil red O-positive staining and expressed adipsin, FABP4, LPL, and PPARγ2 genes by reverse transcriptase polymerase chain reaction (RT-PCR). In osteogenic differentiation, alkaline phosphatase activity and calcium accumulation were detected. RT-PCR studies determined that Cx43, osteopontin, and Runx2 genes were expressed in the osteogenic cultures. Among three cell lines cultured continuously for passage 10, two had normal karyotypes; however, one retained a karyotype of mos 46,XY[19]/47,XY,+mar[3]. These observations suggest that MPCs are present in human umbilical cord and possess several typical traits of MPCs.

Can Levofloxacin Be a Useful Alternative to Trimethoprim-Sulfamethoxazole for Treating Stenotrophomonas maltophilia Bacteremia?

ABSTRACT A retrospective study was conducted to evaluate the efficacy of levofloxacin in the treatment of Stenotrophomonas maltophilia bacteremia. The 30-day mortality rates were similar between the trimerthoprim-sulfamethoxazole (TMP-SMX) and levofloxacin treatment groups. Adverse events related to antibiotics occurred more frequently in patients receiving TMP-SMX, and recurrent bacteremia due to levofloxacin-resistant S. maltophilia strains developed in patients treated with levofloxacin. Our data suggest that levofloxacin can be a useful alternative option for treating S. maltophilia infections.

Clinical predictors of Pseudomonas aeruginosa bacteremia among Gram-negative bacterial infections in non-neutropenic patients with solid tumor

OBJECTIVESnThis study was performed to identify risk factors in Pseudomonas aeruginosa bacteremia among Gram-negative bacterial infections in non-neutropenic patients with solid tumor.nnnMETHODSnA case-control study was performed to identify clinical predictors for P. aeruginosa bacteremia among non-neutropenic patients with Gram-negative bacteremia. Each case of P. aeruginosa bacteremia was matched to one or two controls with Escherichia coli, Klebsiella, Enterobacter or Citrobacter species in non-neutropenic patients with solid tumor.nnnRESULTSnSeventy-eight patients with P. aeruginosa bacteremia were compared with 98 control patients who had other Gram-negative bacteremias. The most common types of cancer were biliary tract cancer (49/176, 27.8%) and hepatocellular carcinoma (38/176, 21.6%), followed by gastric and bladder cancer. Factors associated with development of P. aeruginosa bacteremia were the presence of lung cancer, percutaneous tubes, nosocomial exposure, an invasive procedure and previous antimicrobial therapy (all P < 0.05). Independent risk factors for P. aeruginosa bacteremia included the presence of lung cancer and previous antimicrobial therapy. In the subgroup analysis including 90 patients with community-onset bacteremia, the previous use of antimicrobial agents and presence of bladder cancer were independent factors significantly associated with P. aeruginosa bacteremia.nnnCONCLUSIONSnUnderlying lung cancer and previous antimicrobial treatment were significantly associated with P. aeruginosa bacteremia in non-neutropenic patients with solid tumor. P. aeruginosa should be considered as a probable cause of Gram-negative bacteremia in this patient group.

Risk factors and treatment outcomes of bloodstream infection caused by extended-spectrum cephalosporin-resistant Enterobacter species in adults with cancer

Treatment of Enterobacter infection is complicated due to its intrinsic resistance to cephalosporins. Medical records of 192 adults with cancer who had Enterobacter bacteremia were analyzed retrospectively to evaluate the risk factors for and the treatment outcomes in extended-spectrum cephalosporin (ESC)-resistant Enterobacter bacteremia in adults with cancer. The main outcome measure was 30-day mortality. Of the 192 patients, 53 (27.6%) had bloodstream infections caused by ESC-resistant Enterobacter species. Recent use of a third-generation cephalosporin, older age, tumor progression at last evaluation, recent surgery, and nosocomial acquisition were associated with ESC-resistant Enterobacter bacteremia. The 30-day mortality rate was significantly higher in the resistant group. Multivariate analysis showed that respiratory tract infection, tumor progression, septic shock at presentation, Enterobacter aerogenes as the culprit pathogen, and diabetes mellitus were independent risk factors for mortality. ESC resistance was significantly associated with mortality in patients with E. aerogenes bacteremia, although not in the overall patient population.

Continuous increase of the antimicrobial resistance among gram-negative pathogens causing bacteremia: a nationwide surveillance study by the Korean Network for Study on Infectious Diseases (KONSID).

Antimicrobial susceptibility data for all microorganisms isolated from blood culture were collected from 13 institutions in Korea from June to September 2011. Data were compared with our previous studies performed during 2006-2007 and 2008. The prevalence of MRSA in 2011 has rebounded to 63.7% after a slight decrease in 2008. Vancomycin-resistant Enterococcus faecium declined to 24.1%. The resistance rates of Acinetobacter baumannii to imipenem and meropenem increased from 25.4% and 28.8% to 55.4% and 37.5%, respectively. Ciprofloxacin resistance of Escherichia coli has increased from 23.9% to 30.8%. The resistance rate of Klebsiella pneumoniae to ciprofloxacin has increased from 17.7% to 26.5%. Extended spectrum beta-lactamase-producing E. coli and K. pneumoniae have also seen increased levels of resistance, from 8.6% to 18.4% and 13.6% to 28.5%, respectively. An overall increase in antimicrobial resistance among gram-negative pathogens has been observed. Continued surveillance and intervention to slow the propagation of resistance are necessary.

Outcome of culture-negative pyogenic vertebral osteomyelitis: comparison with microbiologically confirmed pyogenic vertebral osteomyelitis.

OBJECTIVESnAlthough pyogenic vertebral osteomyelitis (PVO) with no identified microorganism is treated empirically, the clinical outcome is not well understood.nnnMETHODSnWe conducted a retrospective review of patients with PVO at a tertiary-care hospital from 2000 through 2012. The study compared clinical features and outcomes of microbiologically confirmed (M-PVO) with clinically diagnosed PVO (C-PVO).nnnRESULTSnOf 151 patients with PVO, 75 (49.7%) had M-PVO. Compared to patients with M-PVO, patients with C-PVO had fewer underlying medical conditions. In addition, they presented less frequently with fever, high acute-phase reactants levels, and paraspinal abscess. The rate of treatment failure tended to be lower in the C-PVO group [9.2% (7/76) vs. 17.3% (13/75); p = 0.157]. The overall relapse rate was 6.6% and did not differ significantly between groups; notably this rate was higher in patients who received antibiotics for ≤ 6 weeks [18.8% (3/16)] and ≤ 8 weeks [12.1% (4/33)]. The independent risk factors for treatment failure were higher CRP levels [odds ratio (OR) = 1.087; 95% confidence interval (CI): 1.025-1.153; p = 0.005] and fever ≥ 37.8°C (OR = 8.556; 95% CI: 2.273-32.207; p = 0.002).nnnCONCLUSIONSnPatients with C-PVO had less systemic inflammatory response and a more favorable outcome compared to M-PVO. Prolonged antibiotic therapy, for at least 8 weeks, might be required for C-PVO, as well as for M-PVO until better outcomes are assured.

Impact of a computerized alert system for bacteremia notification on the appropriate antibiotic treatment of Staphylococcus aureus bloodstream infections

A computerized alert system (CAS) has been introduced to notify bacteremia in real time. We evaluated the impact of the CAS on the administration of appropriate antibiotics in patients with Staphylococcus aureus bloodstream infections (BSIs). We retrospectively reviewed the medical records of patients with S. aureus BSI for each 1-year control and intervention periods, before and after the implementation of the CAS. The proportions of appropriate antibiotic treatment were compared between the control and intervention periods. The 30-day mortality of S. aureus bacteremia was also assessed in the study population. A total of 313 patients were included in the study. Appropriate antibiotics were initiated 7xa0h earlier in the intervention period (mean time, 13.5xa0h vs. 20.0xa0h; pu2009=u20090.136). The administration of appropriate antibiotics within the 24xa0h after blood acquisition was similar between the two periods, but this significantly increased from 3.3xa0% in the control period to 10.6xa0% in the intervention during the 24–36xa0h interval (pu2009=u20090.012). In the subgroup analysis, similar trends were observed in patients with methicillin-resistant isolates (6.7xa0% vs. 18.2xa0%; pu2009=u20090.032) and hospital-onset infection (3.5xa0% vs. 17.1xa0%; pu2009=u20090.004). The independent risk factors for 30-day mortality of S. aureus bacteremia were age, a high Pitt bacteremia score, an increased Charlson’s weighted index of comorbidity, and hospital-onset infection, although the appropriateness of antibiotic therapy within 36xa0h and the CAS were not identified as predictors. The CAS increased the proportion of appropriate antimicrobial therapy during the 24–36xa0h interval after bacteremia onset in patients with S. aureus BSIs.

Risk factor of community-onset spontaneous bacterial peritonitis caused by fluoroquinolone-resistant Escherichia coli in patients with cirrhosis.

Despite the high prevalence of antimicrobial‐resistant Escherichia coli in hospital‐acquired infections, the clinical epidemiology of fluoroquinolone (FQ) resistance in community‐onset spontaneous bacterial peritonitis (SBP) in patients with cirrhosis is not well understood. This study was performed to evaluate clinical features and risk factors for community‐onset SBP caused by FQ‐resistant E. coli.

Mycobacterium Chelonae Infections Associated With Bee Venom Acupuncture

We report 3 cases of Mycobacterium chelonae infections after bee venom acupuncture. All were treated with antibiotics and surgery. Mycobacterium chelonae infections should be included in the differential diagnosis of chronic skin and soft tissue infections following bee venom acupuncture.

In vitro synergistic effects of various combinations of vancomycin and non-beta-lactams against Staphylococcus aureus with reduced susceptibility to vancomycin.

The aim of our study was to determine the potential for synergistic effect of vancomycin combined with a non-beta-lactam agent and of combinations of orally available non-beta-lactam agents against vancomycin-intermediate S. aureus (VISA) and heterogeneous VISA (hVISA). Three VISA isolates, three hVISA isolates, and two vancomycin-susceptible S. aureus (VSSA) isolates were used. The combinations included vancomycin and one of clindamycin, ciprofloxacin, gentamicin, rifampicin, or trimethoprim/sulfamethoxazole. Pairwise combinations among five non-beta-lactam agents were also tested for synergy. Synergy was determined using time-kill curves at 24h. Vancomycin combined with either ciprofloxacin or gentamicin showed synergy against some isolates of VISA, hVISA and VSSA. Vancomycin combined with trimethoprim/sulfamethoxazole showed synergy against VISA and hVISA. Among orally available non-beta-lactam agents, only ciprofloxacin combined with either clindamycin or trimethoprim/sulfamethoxazole showed synergy against one isolate of VISA.