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Biomedical subjects

K T Luh

Publications and source records attributed to K T Luh.

At least 73 records · Page 4Linked to original sources
PubMed2000

Application of pulsed-field gel electrophoresis to the investigation of a nosocomial outbreak of Vibrio parahaemolyticus.

The method of pulsed-field gel electrophoresis (PFGE) for Vibrio parahaemolyticus was first published in 1996. Since then, its application has been seldom reported in the literature. A food poisoning outbreak due to V. parahaemolyticus occurred in five wards of a hospital was investigated using this method. Twenty-five patients were involved and all of them had eaten food supplied by the hospital. Of the 15 cases whose stools were available for culture, only four cultures yielded V. parahaemolyticus. All four isolates were serotype K6 and were indistinguishable or closely related to each other based on PFGE patterns. Two isolates from food were recovered and they presented different characterizations from the patient isolates in both serotype and PFGE pattern. Successful typing by PFGE to identify the outbreak strain and differentiate V. parahaemolyticus strains between patient and food isolates in this study suggests the usefulness of PFGE for V. parahaemolyticus, the leading cause of food poisoning in Taiwan.

Cross Infection↗
PubMed2000

Microbiologic features of adult community-acquired bacterial meningitis in Taiwan.

BACKGROUND AND PURPOSE: Community-acquired bacterial meningitis (CABM) is a life-threatening disease that requires prompt initiation of appropriate antibiotic therapy. The purpose of this study was to determine the causative microorganisms of CABM and their antimicrobial susceptibility patterns at a major teaching hospital in Taipei from 1993 to 1998. METHODS: A review of medical records and microbiologic data was used to identify cases of CABM and causative pathogens. Antimicrobial susceptibility testing for bacterial isolates was performed by the disk diffusion method. RESULTS: Among the 48 adult patients with a diagnosis of CABM during the study period, the causative pathogens were identified in 36 cases. Unlike reports from other countries, Klebsiella pneumoniae was the leading causative pathogen (33%), followed by Streptococcus pneumoniae (28%), Listeria monocytogenes (11%), Neisseria meningitidis (6%), Staphylococcus aureus (6%), streptococci (6%), and Pseudomonas aeruginosa (6%). The incidence of CABM due to K. pneumoniae increased during the study period (p = 0.012, Poisson regression), while the incidence of CABM due to other pathogens remained stable. All of the CABM-associated K. pneumoniae isolates were susceptible to cefotaxime but 25% of the CABM-associated S. pneumoniae strains were not susceptible to penicillin G. CONCLUSIONS: Penicillin G alone was not an appropriate empiric therapy for adult CABM because a high percentage of cases were due to K. pneumoniae or penicillin nonsusceptible S. pneumoniae. While the recommendations for the initial empiric regimen for CABM due to S. pneumoniae in Taiwan remain to be developed, third-generation cephalosporins appear to be an appropriate initial empiric regimen for the treatment of CABM due to K. pneumoniae.

Adolescent↗
PubMed2000

In vitro activity of rifabutin and rifampin against clinical isolates of Mycobacterium tuberculosis in Taiwan.

BACKGROUND AND PURPOSE: To determine the in vitro activity of rifabutin against Mycobacterium tuberculosis (MTB) and the cross-resistance rate between rifampin and rifabutin. METHODS: A total of 56 clinical isolates of MTB, including 23 multidrug-resistant (MDR) isolates and 33 susceptible isolates, were tested for susceptibility to rifampin and rifabutin using the absolute concentration method. The concentrations of drugs tested were 2.5 and 5 mg/mL for rifampin and 0.1, 0.5, 1, 2.5, 5, and 10 mg/mL for rifabutin. RESULTS: All 33 MTB isolates that were susceptible to rifampin were also susceptible to rifabutin. None of the 23 MDR-MTB isolates were inhibited by rifabutin at a concentration of 0.1 mg/mL. Among these 23 MDR isolates, three were susceptible to rifabutin at concentrations > or = 0.5 mg/mL, six were susceptible to rifabutin at concentrations > or = 5 mg/mL, 18 were susceptible to rifabutin at concentrations > or = 10 mg/mL and five were not inhibited at any of the concentrations tested. The cross-resistance rate between rifampin and rifabutin was 87%. CONCLUSIONS: Our results indicate that the in vitro activity of rifabutin against drug-susceptible MTB isolates is greater than that of rifampin. For MDR-MTB isolates, the cross-resistance is high between rifampin and rifabutin.

Antibiotics, Antitubercular↗
PubMed2000

Fatal outcome of Erysipelothrix rhusiopathiae bacteremia in a patient with oropharyngeal cancer.

Bacteremia due to Erysipelothrix rhusiopathiae is rare; the most common presentation reported in the literature is endocarditis. We report a 32-year-old man with oropharyngeal cancer who developed aspiration pneumonia and E. rhusiopathiae bacteremia, and presented with fever, chills, dyspnea, and productive cough with purulent sputum. Despite treatment with amoxicillin/clavulanate and nutritional support for 9 days, he died of respiratory failure. He had no clinical evidence of endocarditis. He had no history of animal or occupational exposure, and might have been colonized with E. rhusiopathiae in the oral cavity, followed by aspiration pneumonia and bacteremia. A fatal outcome in a patient with bacteremia due to E. rhusiopathiae without endocarditis is rare.

Adult↗
PubMed2000

Bacteremia due to Campylobacter species: high rate of resistance to macrolide and quinolone antibiotics.

BACKGROUND AND PURPOSE: Although the rate of isolation of Campylobacter from stool specimens in Taiwan is similar to those in other developed countries, Campylobacter bacteremia has rarely been reported in Taiwan, and the patterns of antimicrobial susceptibility of blood isolates to various antimicrobial agents remain unknown in the Taiwanese population. The purpose of this study was to determine the clinical characteristics of patients with Campylobacter infection in a university hospital in Taiwan and the antimicrobial susceptibility patterns of the Campylobacter isolates. METHODS: We retrospectively reviewed medical records of all patients with Campylobacter bacteremia treated in a university hospital between January 1991 and March 1999. Minimum inhibitory concentrations of 13 antimicrobial agents to 10 stored blood isolates were determined using the E-test. RESULTS: Approximately half (52%) of the 21 patients had chronic liver disease and one-quarter had hepatobiliary or gastrointestinal malignancies. Thirteen (62%) patients had conditions that were associated with gastroenteritis. Other clinical manifestations associated with Campylobacter infection included cellulitis, perinatal sepsis, peritonitis, vascular catheter-related infection, and primary bacteremia. The duration of illness was generally short: approximately half (52%) of the 21 patients had fever lasting for only 1 day. Antimicrobial susceptibility testing of the 10 isolates revealed that most of the blood isolates were resistant to erythromycin and nalidixic acid (100% and 90%, respectively), while the rate of cross-resistance between erythromycin and azithromycin was 70%, and that between nalidixic acid and ciprofloxacin was 67%. CONCLUSIONS: Our observations suggest that Campylobacter bacteremia should be included in the differential diagnosis of patients with chronic liver disease or malignancies involving the hepatobiliary system or gastrointestinal tract who present with fever and gastroenteritis. Clinicians in Taiwan should be alert to the high rate of resistance of Campylobacter isolates to macrolide and quinolone antibiotics.

Adolescent↗
PubMed2000

Comparison of the BACTEC MGIT 960 with Löwenstein-Jensen medium for recovery of mycobacteria from clinical specimens.

SETTING: Taiwan Provincial Chronic Disease Control Bureau. OBJECTIVE: To evaluate the rate of recovery and the mean time to detection (TTD) of mycobacteria in clinical specimens with two culture systems, the BACTEC MGIT 960 and Löwenstein-Jensen (LJ) medium. DESIGN: We studied 365 specimens, collected from 166 patients. Specimens were processed with standard N-acetyl-L-cysteine (NALC)-NaOH method, then inoculated onto BACTEC MGIT 960 and onto LJ slants. RESULTS: A total of 124 mycobacterial isolates (114 Mycobacterium tuberculosis and 10 non-tuberculous mycobacteria) were detected. The recovery rates were 94% (117/124) with BACTEC MGIT 960 and 75.8% (94/124) with LJ. The rates of contamination for each of the systems were 5.5% with BACTEC MGIT 960 and 4.1% with LJ. The TTDs for mycobacteria were 10.7 days with BACTEC MGIT 960 and 30.6 days with LJ. Excluding the non-tuberculous mycobacteria, the TTDs for M. tuberculosis were 11.1 days with BACTEC MGIT 960 and 30.7 days with LJ. The difference in TTD between smear-positive and smear-negative specimens for either mycobacteria (10.0 vs 12.6 days; P = 0.06) or M. tuberculosis (10.1 vs 12.7 days; P = 0.06) with BACTEC MGIT 960 was not statistically significant. CONCLUSION: The BACTEC MGIT 960 system can expedite the recovery of mycobacteria in culture. Combined with conventional solid medium, it also increases the overall recovery of mycobacteria in culture.

Acetylcysteine↗
PubMed2000

Infected chylothorax caused by Streptococcus agalactiae: a case report.

Chylothorax is bacteriostatic in nature. Bacterial infection rarely develops in chylothorax and has never been reported in a non-immunocompromised host. A 33-year-old woman was admitted to National Taiwan University Hospital because of fever and right pleuritic pain. Chest roentgenography and computed tomography revealed right pleural effusion. Examination of the pleural effusion revealed a profile compatible with empyema and chylothorax. Culture of the pleural effusion yielded Streptococcus agalactiae. The woman was not immunocompromised. This is the first report of infected chylothorax caused by Streptococcus agalactiae in a non-immunocompromised host.

Adult↗
PubMed2000

High protease activity of Chryseobacterium indologenes isolates associated with invasive infection.

In order to understand virulence factors of Chryseobacterium indologenes isolates associated with invasive infection, enzymatic activities and cellular fatty acid profiles of 42 isolates recovered at National Taiwan University Hospital from January 1994 to December 1996 were studied. Among them, 12 blood isolates were considered as invasive and 30 (recovered from urine, sputa, infected burn wounds, and catheter tips) were noninvasive. All isolates showed strong activities of alkaline phosphatase, acid phosphatase, naphthol-AS-BI-phosphohydrolase, and N-acetyl-beta-glucosaminidase, and had no activities for alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, and alpha-fucosidase. The activities of other enzymes were variable. Thirty-two isolates (76%) had varying degrees of protease activity. Two profiles (profiles I and II) of cellular fatty acids of the isolates were found and profile I predominated. There was no significant difference of distribution of cellular fatty acid profiles and activities of enzymes between invasive and noninvasive isolates, except protease activity which was significantly higher in invasive isolates than that in noninvasive isolates. Protease activity may play an important role in virulence on invasive infections caused by C. indologenes.

Endopeptidases↗
PubMed2000

Comparison of antimicrobial susceptibility of Citrobacter freundii isolates in two different time periods.

Citrobacter freundii was first identified in 1932, since then it has been reported to cause a variety of infections in aged, immunocompromised, and debilitated patients. With the use of broad-spectrum antibiotics, C. freundii has become increasingly resistant to antimicrobial agents. In order to determine the chronological changes in susceptibility and current susceptibility status of C. freundii, we compared the antimicrobial susceptibility of C. freundii in two different time periods, from 1987 to 1988 and from 1997 to 1998. In both time periods, 61 isolates of C. freundii were randomly selected for study from all clinical isolates at National Taiwan University Hospital. The minimum inhibitory concentrations and susceptible rates of 15 antimicrobial agents were compared, and it was found that most C. freundii isolates were resistant to anti-pseudomonal penicillins, first, second, and third generation cephalosporins, gentamicin, tobramycin, and aztreonam. The results indicate that the susceptible rates of C. freundii to aminoglycosides and ciprofloxacin decreased markedly during the period from 1987 to 1998. Cefepime, cefpirome, imipenem, and meropenem remained the most active agents against C. freundii.

Citrobacter freundii↗
PubMed1999

In vitro activity of quinupristin/dalfopristin against clinical isolates of common gram-positive bacteria in Taiwan.

The MICs of quinupristin/dalfopristin against common Gram-positive bacteria isolated from various clinical specimens at a university hospital in Taiwan were determined by the agar dilution method. The tested bacteria included methicillin-resistant Staphylococcus aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant Staphylococcus epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), Streptococcus pyogenes, Streptococcus pneumoniae, and Enterococcus faecalis. With the exception of E. faecalis all bacteria were susceptible to quinupristin/dalfopristin. The MIC50 and MIC90 were, respectively, 0.25 microgram/mL and 0.5 microgram/mL for both MRSA and MSSA; 0.25 microgram/mL and 0.5 microgram/mL for MRSE; 0.25 microgram/mL and 0.25 microgram/mL for MSSE; 0.125 microgram/mL and 0.125 microgram/mL for S. pyogenes; and < or = 0.03 microgram/mL and 0.25 microgram/mL for S. pneumoniae. Eighty-two percent of the tested E. faecalis isolates were intermediately resistant or resistant to quinupristin/dalfopristin, with an MIC50 of 2 micrograms/mL and an MIC90 of 4 micrograms/mL. Quinupristin/dalfopristin seems to be a promising antimicrobial agent against common Gram-positive bacteria other than E. faecalis in Taiwan.

Anti-Bacterial Agents↗
PubMed1999

Emergence of vancomycin-resistant enterococci at a university hospital in Taiwan: persistence of multiple species and multiple clones.

OBJECTIVES: To describe the epidemiology of vancomycin-resistant enterococci (VRE) in a university hospital in Taipei, Taiwan. DESIGN: Retrospective review over a 27-month period, from March 1996 to May 1998. SETTING: A tertiary-care teaching hospital in Taiwan. PARTICIPANTS: Patients with VRE isolated from any body site. METHODS: Patients were identified through hospital microbiology and infection control records. Patient charts were reviewed for clinical and epidemiology data, including age, gender, previous hospital admissions, underlying diseases, types of infection, and recent antibiotic use. VRE isolates were characterized by their typical biochemical reactions, cellular fatty acid profiles, and the presence of van genes. Antibiotypes using the E-test and randomly amplified polymorphic DNA (RAPD) patterns of these isolates were used to determine the clonality. RESULTS: Twenty-five isolates of VRE recovered from 12 patients were identified. One patient with a perianal abscess had 12 isolates of VRE (4 Enterococcus faecalis, 7 Enterococcus faecium, and 1 Enterococcus casseliflavus) recovered from perianal lesions. Among 3 patients who were hospitalized in the same room, 1 had a community-acquired cellulitis over the left leg caused by E. faecalis, and the other 2 patients both had anal colonization with 2 isolates of E. faecalis. The other 8 patients had 1 E. faecalis isolate each from various clinical specimens. All isolates possessed vanA resistance phenotype and vanA genes. Different antibiotypes and RAPD patterns of the isolates from different patients excluded the possibility of nosocomial spread at the hospital. CONCLUSIONS: Multiple species of VRE (E. faecalis, E. faecium, and E. casseliflavus) and multiple clones of E. faecium could colonize or infect hospitalized patients. In addition, clones of VRE can persist long-term in patients' lower gastrointestinal tracts. These results extend our knowledge of the coexistence and the persistence of multiple species and multiple clones of VRE in hospitalized patients.

Cross Infection↗
PubMed1999

Dissemination of high-level penicillin-, extended-spectrum cephalosporin-, and erythromycin-resistant Streptococcus pneumoniae clones in Taiwan.

Sixty-seven clinical isolates of Streptococcus pneumoniae (40 of serotype 23F, 19 of serotype 19F, and 8 of serotype 6B) with decreased susceptibilities to penicillin and erythromycin were characterized by antimicrobial susceptibility patterns; DNA restriction endonuclease cleavage profiles of the penicillin-binding protein genes pbp1a, pbp2b, and pbp2x; random amplified polymorphic DNA (RAPD) patterns generated by arbitrarily primed PCR; and chromosomal macrorestriction profiles based on pulsed-field gel electrophoresis. A total of 22 clones (identical or closely related pulsotypes and identical RAPD patterns) were identified; 14 clones of 23F, 6 of 19F, and 2 of 6B. Three 23F clones (26 isolates) and one 19F clone (9 isolates) expressed high-level resistance to penicillin, cefotaxime, and erythromycin (MICs >/= 256 microg/ml). These data strongly suggest that multiple high-level penicillin-, extended-spectrum cephalosporin-, and macrolide-resistant clones of S. pneumoniae have been disseminated in Taiwan.

Adult↗
PubMed1999

Bacteremia due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a pediatric oncology ward: clinical features and identification of different plasmids carrying both SHV-5 and TEM-1 genes.

Thirteen patients who had 16 episodes of bacteremia were observed between 1993 and 1997 in a pediatric oncology ward with a high background isolation rate of cefotaxime- or aztreonam-resistant gram-negative bacteria. Four blood isolates were Escherichia coli and 12 were Klebsiella pneumoniae, and these isolates harbored extended-spectrum beta-lactamases (ESBLs). All episodes of bacteremia were nosocomial, all except one of the episodes occurred in neutropenic patients, and all patients were treated with piperacillin or ceftazidime with amikacin and cefazolin prior to the onset of bacteremia. Nine of 13 patients were receiving extended-spectrum beta-lactam treatment when the bacteremias caused by ESBL producers occurred. Molecular studies revealed that four K. pneumoniae SHV-2-producing isolates from 1994 were of the same clone. Other ESBL producers, including six that carried both TEM-1 and SHV-5, five that carried SHV-5, and one that carried SHV-2 alone, were unrelated. In conclusion, SHV-5 was present in 11 of the 16 isolates and coexisted with TEM-1 in 6 isolates. Acquisition of resistance genes probably occurred under antibiotic selection pressure. This study highlights the importance of routine checks for and detection of ESBL producers. Effective therapy against ESBL producers should be considered early for children who have malignancies and neutropenia and who are septic, despite treatment with a regimen that includes an extended-spectrum beta-lactam, in a clinical setting of an increased incidence of ESBL-producing bacteria.

Adolescent↗
PubMed1999

Dissemination of two methicillin-resistant Staphylococcus aureus clones exhibiting negative staphylase reactions in intensive care units.

From December 1997 to March 1998, 25 methicillin-resistant Staphylococcus aureus (MRSA) isolates exhibiting negative Staphylase (Oxoid Ltd., Basingstoke, England) reactions were identified from various clinical specimens from 13 patients in six intensive care units (ICUs) or in wards following a stay in an ICU at the National Taiwan University Hospital. The characteristics of these isolates have not been previously noted in other MRSA isolates from this hospital. Colonies of all these isolates were grown on Trypticase soy agar supplemented with 5% sheep blood and were nonhemolytic and unpigmented. Seven isolates, initially reported as Staphylococcus haemolyticus (5 isolates) and Staphylococcus epidermidis (2 isolates) by the routine identification scheme and with the Vitek GPI system (bioMerieux Vitek, Inc., Hazelwood, Mo.), were subsequently identified as S. aureus by positive tube coagulase tests, standard biochemical reactions, and characteristic cellular fatty acid chromatograms. The antibiotypes obtained by the E test, coagulase types, restriction fragment length polymorphism profiles of the staphylococcal coagulase gene, and random amplified polymorphic DNA patterns generated by arbitrarily primed PCR of the isolates disclosed that two major clones disseminated in the ICUs. Clone 1 (16 isolates) was resistant to clindamycin and was susceptible to trimethoprim-sulfamethoxazole (TMP-SMZ) and was coagulase type II. Clone 2 (eight isolates) was resistant to clindamycin and TMP-SMZ and was coagulase type IV. These two epidemic clones from ICUs are unique and underline the need for caution in identifying MRSA strains with colonial morphologies not of the typical type and with negative Staphylase reactions.

Adult↗
PubMed1999

Extremely high incidence of macrolide and trimethoprim-sulfamethoxazole resistance among clinical isolates of Streptococcus pneumoniae in Taiwan.

From January 1996 to December 1997, 200 isolates of Streptococcus pneumoniae recovered from 200 patients treated at National Taiwan University Hospital were serotyped and their susceptibilities to 16 antimicrobial agents were determined by the agar dilution method. Sixty-one percent of the isolates were nonsusceptible to penicillin, exhibiting either intermediate resistance (28%) or high-level resistance (33%). About two-fifths of the isolates displayed intermediate or high-level resistance to cefotaxime, ceftriaxone, cefepime, imipenem, and meropenem. Extremely high proportions of the isolates were resistant to erythromycin (82%), clarithromycin (90%), and trimethoprim-sulfamethoxazole (TMP-SMZ) (87%). Among the isolates nonsusceptible to penicillin, 23.8% were resistant to imipenem; more than 60% displayed resistance to cefotaxime, ceftriaxone, cefepime, and carbapenems; 96.7% were resistant to erythromycin; and 100% were resistant to TMP-SMZ. All isolates were susceptible to rifampin and vancomycin. The MICs at which 50% and 90% of the isolates were inhibited were 0.12 and 1 microgram/ml, respectively, for cefpirome, and 0.12 and 0.25 microgram/ml, respectively, for moxifloxacin. Six serogroups or serotypes (23F, 19F, 6B, 14, 3, and 9) accounted for 77.5% of all isolates. Overall, 92.5% of the isolates were included in the serogroups or serotypes represented in the 23-valent pneumococcal vaccine. The incidence of macrolide and TMP-SMZ resistance for S. pneumoniae isolates in Taiwan in this study is among the highest in the world published to date.

Adolescent↗
PubMed1999

Septic shock due to Helicobacter fennelliae in a non-human immunodeficiency virus-infected heterosexual patient.

Helicobacter fennelliae (formerly Campylobacter fennelliae) has been reported to cause bacteremia in homosexual men with or without human immunodeficiency virus (HIV) infection. We report here a 48-year-old, non-HIV-infected, heterosexual man with diabetes mellitus and cirrhosis of the liver who developed bacteremia and septic shock due to H. fennelliae. The patient was treated successfully initially with intravenous ampicillin-sulbactam and ceftazidime, followed by ampicillin-sulbactam only. These agents were active in vitro against the isolate by E-test results. To our knowledge, this is the first documented case of septic shock due to H. fennelliae in a non-HIV-infected, heterosexual, immunocompromised patient.

Bacteremia↗