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Biomedical subjects

M N Kim

Publications and source records attributed to M N Kim.

11 recordsLinked to original sources
PubMed2002

Risk factors for penicillin resistance and mortality in Korean adults with Streptococcus pneumoniae bacteremia.

A retrospective analysis was performed to measure the incidence of pneumococcal bacteremia and to identify risk factors for penicillin resistance and prognostic factors for outcome in adults. A total of 151 cases of pneumococcal bacteremia were identified from 149 adults during the period 1996-2000. The overall rate of penicillin resistance was 49%, ranging from 54.2% in 1996 to 48.5% in 2000 (P=0.93). Rates of resistance to ceftriaxone, clindamycin, erythromycin, and trimethoprim-sulfamethoxazole were 21.6%, 51%, 62%, and 44.7%, respectively. Multidrug resistance was documented in 47.7% of the cases. Penicillin resistance was significantly associated with solid tumor, biliary drainage catheter, and previous beta-lactam therapy in the univariate analysis. However, the associations were not as significant as independent risk factors in the multivariate analysis. Mortality was 23.8% and did not change significantly during the study period (P=0.06). Mortality rates in cases caused by penicillin-susceptible Streptococcus pneumoniae and penicillin-resistant Streptococcus pneumoniae were 23% and 24.7%, respectively (P=0.81). Mortality was not significantly influenced by penicillin resistance, even high-level resistance (24.4% vs. 20%; P=0.64). Multivariate analysis revealed that antineoplastic chemotherapy, respiratory failure, and acute renal failure were independent prognostic factors for mortality. In conclusion, the rate of penicillin resistance among pneumococcal blood isolates was high in the late 1990s, but penicillin resistance, and even high-level penicillin resistance, was not significantly associated with increased mortality in adults with pneumococcal bacteremia.

Adolescent↗
PubMed2001

Group B streptococcal bacteremia in nonpregnant adults with hepatic disease in Korea.

Sixty-seven cases of group B streptococcal bacteremia in adults were retrospectively reviewed during the period 1991-2000. Not one case occurred in pregnant women. The mean age of the patients was 57 years, and 67.2% were men. Of the 67 cases of illness, 25.4% were hospital acquired and 11.9% were polymicrobial. Common predisposing diseases included hepatic disease (55.2%), diabetes mellitus (28.4%), malignancy (20.9%), and cardiovascular diseases (17.9%). Primary bacteremia, peritonitis, bone and joint infections, and skin and soft tissue infections accounted for most presentations. Peritonitis was a more common presentation in patients with hepatic disease (P<0.001), whereas skin and soft tissue infection was more common in patients with non-hepatic disease (P=0.008). More patients with hepatic disease had polymicrobial bacteremia than did patients with nonhepatic disease (P=0.018). Death occurred in 9.8% of cases, and mortality did not differ between patients with hepatic disease and those with nonhepatic disease. Hepatic disease was found to be an important predisposing condition in adults with group B streptococcal bacteremia. However, mortality for patients with hepatic disease was similar to that for patients with nonhepatic disease.

Adult↗
PubMed2001

Toxicity and biodegradation of products from polyester hydrolysis.

Toxicity of products from polyester hydrolysis such as succinic acid (SA), adipic acid (AA), mandelic acid (MA), terephthalic acid (TA), 1,4-butanediol (1,4-B), ethylene glycol (EG), styrene glycol (SG) and 1,4-cyclohexane dimethanol (1,4-C) was evaluated by phytotoxicity test on germination of young radish seeds and by cytotoxicity test on HeLa cells. The phytotoxicity test revealed SG > MA > 1,4-C > AA approximately SA > TA approximately EG > 1,4-B in order of decreasing toxicity taking into consideration the growth behavior after germination as well as the percentage of germination. Toxicity on HeLa cells decreased in slightly different order compared to that on young radish seeds, i.e. SG > 1,4-C > MA > TA > SA > AA > EG > 1,4-B. Tests for the phytotoxicity and for cytotoxicity indicated that the aromatic compounds were more harmful than the aliphatic ones. Each group of 4 strains which grew most rapidly on each agar plate containing SA, AA, MA, TA, 1,4-B, EG, SG and 1,4-C respectively as a sole carbon source was identified by the fatty acid methyl esters analysis. The modified Sturm test was carried out using the single isolated strain, an activated sludge or a mixed soil to measure the rate of mineralization of the compounds into carbon dioxide. The aliphatic compounds were mineralized more easily than the aromatic compounds. 1,4-C showed the most exceptionally slow degradation. A scrutiny of residual 1,4-C after degradation is required before polyesters containing 1,4-C could be classified into compostable because 1,4-C has detrimental effects on young radish seeds and HeLa cells and has a tendency to accumulate in the environment due to its slow degradability.

Animals↗
PubMed2000

Vancomycin-intermediate Staphylococcus aureus in Korea.

Recent reports on some methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin have been a major concern in Korea because of the widespread use of vancomycin due to a high prevalence of MRSA in the country. We describe a 45-year-old man with long-standing pelvic abscess due to MRSA. In spite of vancomycin and teicoplanin treatment for a long period of time, the patient died from MRSA sepsis. The blood culture isolate of MRSA exhibited reduced susceptibility to vancomycin (MIC, 8 microg/ml). This is the first report of a vancomycin-intermediate S. aureus case from Korea.

Abdominal Abscess↗
PubMed2000

In vitro activities of quinupristin/dalfopristin and eight other antimicrobial agents against 360 clinical isolates from Korea.

The emergence of multi-drug resistant gram-positive cocci such as methicillin-resistant (MR) staphylococci, vancomycin-resistant (VR) enterococci, and vancomycin-intermediate resistant S. aureus (VISA) has given new urgency to the development of new antimicrobial agents. One of these is quinupristin/dalfopristin (Q/D). We decided to determine the susceptibility of gram-positive cocci isolated at two university hospitals in Seoul to Q/D and compare the results with eight other antimicrobial agents. We investigated 120 isolates of S. aureus including 49 MRSAs and one VISA, 120 isolates of coagulase negative staphylococci (CNS), 64 E. faecalis and 56 E. faecium, including seven strains of VR E. faecium. Minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) for several antimicrobials, including vancomycin and Q/D, were determined by broth microdilution. All S. aureus including VISA were susceptible to Q/D. Q/D MIC90 for both methicillin-susceptible S. aureus (MSSA) and MRSA was 0.25 g/mL. 49 (87.5%) of 56 E. faecium including six of seven VR E. faecium were susceptible to Q/D. E. faecalis were not susceptible to Q/D (only 1.5% susceptible), but were inhibited by ampicillin (94% susceptible) or vancomycin (95%). CNS was susceptible to Q/D (96% susceptible) and vancomycin (100% susceptible). One of 38 staphylococci and two of 17 E. faecium were tolerant to Q/D. In conclusion, Q/D showed excellent activity against all species of gram-positive cocci including MRSA, VISA, and VR E. faecium except E. faecalis, and may provide a valuable option for the treatment of infections caused by these emerging nosocomial pathogens of gram-positive cocci.

Anti-Bacterial Agents↗
PubMed1999

Biochemical oxygen demand sensor using Serratia marcescens LSY 4.

A microbial biochemical oxygen demand (BOD) sensor consisting of Serratia marcescens LSY 4 and an oxygen electrode was prepared for estimation of the biochemical oxygen demand. The response of the BOD sensor was insensitive to pH in the range of pH 6.0-8.0, and the baseline drift of the signal was nearly absent even in unbuffered aqueous solution. Because heavy metal ions were precipitated from the phosphate buffer solution, unbuffered solution was used to investigate the effect of the concentration of heavy metal ions on the sensor response. Contrary to previous studies, not only Cu2+ and Ag+ but also Cd2+ and Zn2+ significantly decreased the response of the BOD sensor in unbuffered solution. Graft polymerization of sodium styrene sulfonate on the surface of the porous teflon membrane was carried out to absorb the heavy metal ions permeating through the membrane. Tolerance against Zn2+ was induced for S. marcescens LSY 4 to make the cells less sensitive to the presence of heavy metal ions. The membrane modification and the Zn2+ tolerance induction showed some positive effects in such a way that they reduced the inhibitory effects of Zn2+ and Cd2+ on the sensitivity of the BOD sensor. However, they had no effect on the protection of the cells against the interference of Cu2+ and Ag+ on the performance of the sensor.

Biosensing Techniques↗
PubMed1998

Antimicrobial resistance in enterococci.

Enterococci have emerged as a major nosocomial pathogen and as an ever-increasing problem in antimicrobial resistance. They are ubiquitous in the intestinal flora of humans and animals and inherently resistant to a wide array of antimicrobial agents, and, more alarmingly, they seem to have a potential facility for acquiring new resistance determinants, including beta-lactamase production, high-level resistance to aminoglycosides, and recently, glycopeptide resistance. Collectively, all of these properties make enterococci one of most difficult nosocomial pathogens to treat and control today. The purpose of this review was to examine the epidemiology, the mechanisms, and laboratory detection of resistance of enterococci to the two major groups of antibiotics: aminoglycosides and glycopeptides.

Aminoglycosides↗
PubMed1994

Gene cloning of the human cytomegalovirus (HCMV) antigen reactive with the serum from a HCMV-infected patient.

The human cytomegalovirus(HCMV) gene encoding the protein reactive with the sera of HCMV-infected patient was cloned and characterized. A reactive phage clone was screened from a lambda gt11 expression library of cDNA of HCMV AD169 strain using HCMV-infected patient sera. The recombinant protein was expressed as 138 kDa-fusion protein with beta-galactosidase, which was reactive with IgM or IgG HCMV antibody-positive sera, but not with anti-HCMV antibody-negative sera. A homology search of the DNA sequence of the cloned gene with HCMV AD169 sequences revealed that it was composed of 709 base pairs spanning between 0.174 and 0.177 map units of the UL32 region of the HCMV AD169 strain genome. This position corresponded to a part of the gene encoding 150 kDa phosphoprotein-(pp150), a major tegument protein, which was reported as an immunogenic protein which evoked strong and longstanding antibody response and had no sequence homology with the proteins of other herpesviruses. These results suggested that pp150 was an immunogenic protein in natural HCMV infection and therefore this clone was regarded as a useful candidate for developing an antigen for the serodiagnosis of HCMV.

Antibodies, Viral↗
PubMed1982

Steroid modifications with immobilized biocatalysts--use of immobilized enzyme-requiring cofactor regeneration and of immobilized mycelium.

Two biological approaches have been investigated for specific modifications of steroids. The first one uses the purified enzyme for the specific dehydrogenation of androsterone to androstanedione. The enzyme used is 3 alpha-hydroxysteroid dehydrogenase which requires a cofactor (NAD). A cofactor regeneration is needed so that the process could work continuously. The conjugation of two points (immobilization of the enzyme and optimization of the ratio methanol-water) allows a continuous work of the enzyme during 25 days. Moreover, we propose a chemical regeneration of the cofactor using methoxy derivative of phenazine methosulphate. Right now it is the limiting step of the process. The second approach of steroid modification uses a whole mycelium of Aspergillus phoenicis for the specific hydroxylation of progesterone to 11 alpha-hydroxy progesterone. The transformation of 90% of the progesterone is obtained with calcium alginate immobilization and the lowest number of products is obtained at pH lower than 2.5 with carrageenan and polyurethane immobilization. It seems promising to apply immobilized biocatalysts to the bioconversion of hydrophobic compounds in organic solvents system.

3-Hydroxysteroid Dehydrogenases↗
PubMedDate not supplied

Time-kill studies of antimicrobial combinations including cefotaxime, ceftriaxone, vancomycin and meropenem against cephalosporin-resistant Streptococcus pneumoniae.

BACKGROUND: Resistance of Streptococcus pneumoniae to penicillin is now widespread and rapidly increasing all over the world. This has led to the critical need for alternative antimicrobial therapy. METHODS: To assess the activities of antimicrobial combinations, including cefotaxime, ceftriaxone, vancomycin and meropenem, time-kill studies were conducted against five strains of penicillin- and cephalosporin-resistant S. pneumoniae at clinically achievable antimicrobial concentrations in cerebrospinal fluid. RESULTS: Combinations of an extended-spectrum cephalosporin with vancomycin were not synergistic. Meropenem had a comparable bactericidal activity to those combinations, and its killing activity was not affected by the addition of cefotaxime, ceftriaxone or vancomycin. CONCLUSIONS: It is suggested that meropenem could be an effective alternative for the treatment of penicillin- and cephalosporin-resistant pneumococcal meningitis. However, more clinical data are required before it can be recommended as an effective antimicrobial agent for such cases.

Anti-Bacterial Agents↗