Biomedical subjects

Wen-Kuei Huang

Publications and source records attributed to Wen-Kuei Huang.

14 recordsLinked to original sources

PubMed2006

In vitro activities of various piperacillin and sulbactam combinations against bacterial pathogens isolated from Intensive Care Units in Taiwan: SMART 2004 programme data.

We investigated the in vitro activity of various piperacillin and sulbactam combinations against Gram-negative bacterial isolates from Intensive Care Units (ICUs) in Taiwan. Antimicrobial susceptibility testing of 1030 bacterial isolates recovered from ICUs of nine major teaching hospitals was performed using the agar dilution method. Sulbactam was added to piperacillin either at a fixed sulbactam concentration of 4 mg/L and 8 mg/L or at a piperacillin:sulbactam ratio of 2:1 and 4:1. Piperacillin/sulbactam at a ratio of 2:1 or a fixed 8 mg/L concentration of sulbactam had better activities against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Serratia marcescens than other piperacillin/sulbactam formulations. For Pseudomonas aeruginosa, piperacillin/sulbactam (2:1 or 4:1 ratios) had MIC(90) values (minimum inhibitory concentration for 90% of the organisms) of 64 mg/L (>90% susceptibility) compared with 64 mg/L for cefoperazone/sulbactam (68% susceptibility) and 128 mg/L for piperacillin/tazobactam (82% susceptibility). For Acinetobacter baumannii, both piperacillin/sulbactam (either 2:1 ratio or a fixed 8 mg/L sulbactam) and cefoperazone/sulbactam were the most potent agents. Adding sulbactam to piperacillin resulted in increased susceptibility rates among piperacillin-resistant P. aeruginosa (53-57% in either 2:1 or 4:1 ratios) and A. baumannii (38-46% in either 2:1 ratio or a fixed 8 mg/L concentration of sulbactam) isolates. Results of susceptibility tests with piperacillin/sulbactam are dependent on the method used. Piperacillin/sulbactam combinations possessed better in vitro activities than piperacillin alone or piperacillin/tazobactam against P. aeruginosa and A. baumannii.

Bacteria↗

PubMed2006

Comparison of in vitro activities of tigecycline with other antimicrobial agents against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in Taiwan.

We compared the in vitro activities of tigecycline to those of other agents against 300 nonduplicate isolates of Streptococcus pneumoniae (194 isolates), Haemophilus influenzae (60 isolates), and Moraxella catarrhalis (46 isolates) recovered from patients treated in three major hospitals in Taiwan from August through December, 2003. All of these isolates were inhibited at 0.5 mg/L of tigecycline. For S. pneumoniae isolates, 72% were not susceptible to penicillin (69% intermediate and 3% resistant) and 96% were not susceptible to azithromycin. Among the 178 isolates resistant to azithromycin, 53 isolates (30%) had the M phenotype and 70% had the cMLSB phenotype. The rate of nonsusceptibility to ertapenem, telithromycin, moxifloxacin, and quinupristindalfopristin in S. pneumoniae was 3%, 2%, 1%, and 57%, respectively. For H. influenzae, 36 (60%) were not susceptible to ampicillin, among which 31 possessed beta-lactamase. A high rate (8.3%) of H. influenzae isolates with beta-lactamase-negative and ampicillin-resistant phenotype was found. All H. influenzae isolates were susceptible to azithromycin, but 40% of them were not susceptible to clarithromycin. Ninety-eight percent (44 isolates) of M. catarrhalis possessed beta-lactamase. All three fluoroquinolones tested were highly active (MIC90 < or =0.12 mg/L) against H. influenzae and M. catarrhalis.

Anti-Bacterial Agents↗

PubMed2005

In vitro activities of tigecycline, ertapenem, isepamicin, and other antimicrobial agents against clinically isolated organisms in Taiwan.

This study evaluated the in vitro activities of tigecycline, ertapenem, isepamicin, and other comparators against 861 bacterial isolates recovered from patients treated in three major teaching hospitals in 2003. MICs to antimicrobial agents were determined by the agar dilution method. High rates of oxacillin resistance (58%) in Staphylococcus aureus (60 isolates), and vancomycin resistance (21%) and quinupristin-dalfopristin non-susceptibility (39%) in Enterococcus faecium (34 isolates) were found. Carbapenems had excellent in vitro activities (>or=98% susceptibility) against the 419 isolates of Enterobacteriaceae, with the MIC(50) and MIC(90) of imipenem, meropenem, and ertapenem being 0.25 and 4 mg/L, 0.03 and 0.12 mg/L, and 0.03 and 0.5 mg/L, respectively. For, Pseudomonas aeruginosa (74 isolates) and Burkholderia cepacia (21 isolates), meropenem (MIC(90), 0.25, 2, and 4 mg/L, respectively) had better in vitro activities than imipenem (MIC(90), 8, 4, and 32 mg/L, respectively) and ertapenem (MIC(90), 0.5, >32, and 32 mg/L, respectively). Isepamicin had a similar activity with amikacin against all Enterobacteriaceae, Pseudomonas aeruginosa, B. cepacia, and Acinetobacter baumannii, except for C. freundii isolates in which isepamicin had an eight-fold activity better than amikacin. Tigecycline had excellent in vitro activities against all isolates tested (MIC(90), <or=1 mg/L) including 14 pandrugresistant A. baumannii isolates (MICs, 1-4 mg/L), except for Proteus mirabilis (59 isolates; MIC(90), 8 mg/L), Bacteroides fragilis (60 isolates; MIC(90), 8 mg/L), P. aeruginosa (MIC(90), 16 mg/L), and B. cepacia (21 isolates; MIC(90), 16 mg/L). Tigecycline, carbapenems, and isepamicin exhibited better or comparable in vitro activities against a wide spectrum of commonly encountered bacteria than other comparator antimicrobials and may represent therapeutic options for infections due to multidrug-resistant pathogens.

Anti-Bacterial Agents↗

PubMed2005

Discordant molecular characterization results in a Mycobacterium avium complex strain isolated from an AIDS patient.

This report describes an unusual strain of Mycobacterium avium complex isolated from the sputum of an immunocompromised AIDS patient, which did not react with the MAC probe of the BDProbe Tec system, but was identified as Mycobacterium intracellulare by 16S rRNA gene sequencing. Its PCR restriction-enzyme analysis pattern was compatible with an allelic variant of M. avium. It was scotochromogenic, slow-growing and phenotypically identified as Mycobacterium scrofulaceum. Its clinical significance is not certain.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Antifungal susceptibilities of clinical isolates of Candida species, Cryptococcus neoformans, and Aspergillus species from Taiwan: surveillance of multicenter antimicrobial resistance in Taiwan program data from 2003.

The susceptibilities of nonduplicate isolates to six antifungal agents were determined for 391 blood isolates of seven Candida species, 70 clinical isolates (from blood or cerebrospinal fluid) of Cryptococcus neoformans, and 96 clinical isolates of four Aspergillus species, which were collected in seven different hospitals in Taiwan (as part of the 2003 program of the study group Surveillance of Multicenter Antimicrobial Resistance in Taiwan). All isolates of Candida species other than C. glabrata and C. krusei were susceptible to fluconazole. Among the 59 C. glabrata isolates, 16 (27%) were not susceptible to fluconazole, and all were dose-dependently susceptible or resistant to itraconazole. For three (5.1%) C. glabrata isolates, voriconazole MICs were 2 to 4 microg/ml, and for all other Candida species isolates, voriconazole MICs were </=0.5 microg/ml. The proportions of isolates for which amphotericin B MICs were >/=2 microg/ml were 100% (3 isolates) for C. krusei, 11% (23 of 207 isolates) for Candida albicans, 3.0% (2 of 67 isolates) for Candida tropicalis, 20% (12 of 59 isolates) for C. glabrata, and 0% for both Candida parapsilosis and Candida lusitaniae. For three (4%) Cryptococcus neoformans isolates, fluconazole MICs were >/=16 microg/ml, and two (3%) isolates were not inhibited by 1 mug of amphotericin B/ml. For four (4.2%) of the Aspergillus isolates, itraconazole MICs were 8 microg/ml. Aspergillus flavus was less susceptible to amphotericin B, with the MICs at which 50% (1 microg/ml) and 90% (2 microg/ml) nsrsid417869\delrsid7301351 of isolates were inhibited being twofold greater than those for Aspergillus fumigatus and Aspergillus niger. All Aspergillus isolates were inhibited by </=1 microg of voriconazole/ml, including isolates with increased resistance to amphotericin B and itraconazole. This study revealed the emergence in Taiwan of decreased susceptibilities of Candida species to amphotericin B and of C. neoformans to fluconazole and amphotericin B. Voriconazole was the most potent agent against the fungal isolates tested, including fluconazole- and amphotericin B-nonsusceptible strains.

Antifungal Agents↗

PubMed2004

Use of MGIT 960 for rapid quantitative measurement of the susceptibility of Mycobacterium tuberculosis complex to ciprofloxacin and ethionamide.

OBJECTIVES: Tentative standards for testing MICs for Mycobacterium tuberculosis include agar dilution and the BACTEC method. However, the conventional agar dilution method requires 3-5 weeks to complete; whereas BACTEC, although a rapid test, involves the use of radioisotopes. In contrast, the MGIT 960 system uses a fluorescence quenching based oxygen sensor that can be read automatically. This system is not only robust, safe and simple, but has been validated for susceptibility tests of first-line antituberculous agents. METHODS: We evaluated 46 clinical strains of M. tuberculosis isolated from patients admitted to Kaohsiung Veterans General Hospital. Testing of MICs of ciprofloxacin and ethionamide was carried out by MGIT 960 and compared with the agar dilution method. RESULTS: Good agreement was found between MGIT 960 and agar dilution. The greatest concordance between the agar dilution and MGIT assay at +/-1 and +/-2 dilution was 80.4% and 97.8% for ciprofloxacin, and 82.6% and 93.5% for ethionamide, respectively. CONCLUSION: MGIT 960 was found to be comparable to the current NCCLS standard method, agar dilution, and has the advantage of being rapid (obtaining results within 5-17 days, average 8.9 days) and easy to achieve standardization.

Antitubercular Agents↗

PubMed2004

Ciprofloxacin-resistant Salmonella enterica Typhimurium and Choleraesuis from pigs to humans, Taiwan.

We evaluated the disk susceptibility data of 671 nontyphoid Salmonella isolates collected from different parts of Taiwan from March 2001 to August 2001 and 1,261 nontyphoid Salmonella isolates from the National Taiwan University Hospital from 1996 to 2001. Overall, ciprofloxacin resistance was found in 2.7% (18/671) of all nontyphoid Salmonella isolates, in 1.4% (5/347) of Salmonella enterica serotype Typhimurium and in 7.5% (8/107) in S. enterica serotype Choleraesuis nationwide. MICs of six newer fluoroquinolones were determined for the following isolates: 37 isolates of ciprofloxacin-resistant (human) S. Typhimurium (N = 26) and Choleraesuis (N = 11), 10 isolates of ciprofloxacin-susceptible (MIC <1 mg/mL) (human) isolates of these two serotypes, and 15 swine isolates from S. Choleraesuis (N = 13) and Typhmurium (N = 2) with reduced susceptibility to ciprofloxacin (MIC >0.12 microg/mL). Sequence analysis of the gryA, gyrB, parC, parE, and acrR genes, ciprofloxacin accumulation, and genotypes generated by pulsed-field gel electrophoresis with three restriction enzymes (SpeI, XbaI, and BlnI) were performed. All 26 S. Typhimurium isolates from humans and pigs belonged to genotype I. For S. Choleraesuis isolates, 91% (10/11) of human isolates and 54% (7/13) of swine isolates belonged to genotype B. These two genotypes isolates from humans all exhibited a high-level of resistance to ciprofloxacin (MIC 16-64 mg/mL). They had two-base substitutions in the gyrA gene at codons 83 (Ser83Phe) and 87 (Asp87Gly or Asp87Asn) and in the parC gene at codon 80 (Ser80Arg, Ser80Ile, or Ser84Lys). Our investigation documented that not only did these two S. enterica isolates have a high prevalence of ciprofloxacin resistance nationwide but also that some closely related ciprofloxacin-resistant strains are disseminated from pigs to humans.

Adolescent↗

PubMed2004

Multicenter surveillance of antimicrobial resistance of Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis to 14 oral antibiotics.

BACKGROUND AND PURPOSE: Data on the in vitro activities of orally administered cephalosporins, particularly third-generation cephalosporins, against recent pathogens responsible for community-respiratory tract infection are lacking. METHODS: A susceptibility surveillance of 267 isolates of Streptococcus pneumoniae, 205 of Streptococcus pyogenes, 204 of Haemophilus influenzae, and 147 of Moraxella catarrhalis to 14 oral antimicrobial agents using the agar dilution method was carried out from March 2002 to October 2002 in Taiwan. RESULTS: High rates of non-susceptibility to penicillin (60%), cefaclor (67%), cefuroxime (62%), cefpodoxime (64%), clarithromycin (91%), and trimethoprim-sulfamethoxazole (98%) for S. pneumoniae isolates and high rates of non-susceptibility to ampicillin (70%), clarithromycin (34%), and trimethoprim-sulfamethoxazole (63%) for H. influenzae isolates were found. The rank order of oral cephalosporin activity based on the minimum concentrations at which 90% of the isolates were inhibited (MIC90s) for S. pneumoniae was cefpodoxime > cefuroxime > cefixime > cefaclor, cephradine > cephalexin and for H. influenzae and M. catarrhalis was cefixime > cefpodoxime > cefuroxime > cefaclor > cephalexin, cephradine. Among the 75 S. pneumoniae isolates resistant to penicillin (MICs ranged 2 to 4 mg/L), 4% were intermediate to amoxicillin and > 90% were resistant to cefaclor, cefuroxime, and cefpodoxime. For S. pyogenes isolates, all were susceptible to penicillin, 21% were not susceptible to clarithromycin and 4% were not susceptible to clindamycin. Thirty four percent of H. influenzae isolates were not susceptible to clarithromycin. The MIC90 of clarithromycin against M. catarrhalis isolates was 0.5 mg/L. CONCLUSIONS: Cefpodoxime, cefixime, and cefuroxime are promising agents against these bacterial pathogens, except for penicillin-non-susceptible S. pneumoniae isolates.

Anti-Bacterial Agents↗

PubMed2003

Rapid detection of pulmonary tuberculosis using the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay (DTB).

The ability to rapidly detect tubercle bacilli in respiratory secretions was determined for the BDProbeTEC ET Mycobacterium tuberculosis Complex Direct Detection Assay in comparison with the acid-fast smear (AFS). A total of 267 respiratory specimens obtained from 89 patients were evaluated. The DTB assay was positive in 70 of 78 culture positive specimens (89.7%) and 12 of 177 culture negative specimens (6.8%). The AFS was positive in 33 of 78 culture positive specimens (42.3%) and 3 of 186 culture negative specimens (1.6%). The sensitivity, specificity, positive predictive value, and negative predictive value of DTB assay were 89.7%, 93.7%, 85.4%, and 95.7%, respectively. The sensitivity of a single DBT (74.4%) was 2.1-times greater than three AFS (35.9%). The greater cost of the DTB assay compared to the AFS was compensated by its valuable information for the diagnosis and control of tuberculosis. These results demonstrated the clinical usefulness of the DTB assay for the rapid diagnosis of tuberculosis in respiratory specimens.

Bacteriological Techniques↗

PubMed2003

Correlation between pyrazinamide activity and pncA mutations in Mycobacterium tuberculosis isolates in Taiwan.

A total of 76 clinical Mycobacterium tuberculosis isolates from Taiwan were tested for pyrazinamidase activity, pyrazinamide susceptibility, and pncA mutations. Frequency of resistance to PZA rose with increases in resistance to first-line drugs. Of 17 pyrazinamide-resistant strains, 7 (3 of which had not been previously described) possessed mutations in the pncA gene.

Amidohydrolases↗

PubMed2003

Telithromycin- and fluoroquinolone-resistant Streptococcus pneumoniae in Taiwan with high prevalence of resistance to macrolides and beta-lactams: SMART program 2001 data.

There is a high prevalence of beta-lactam- and macrolide-resistant Streptococcus pneumoniae in Taiwan. To understand the in vitro susceptibilities of recent isolates of S. pneumoniae to fluoroquinolones and telithromycin (which is not available in Taiwan), the MICs of 23 antimicrobial agents for 936 clinical isolates of S. pneumoniae isolated from different parts of Taiwan from 2000 to 2001 were determined by the agar dilution method. Overall, 72% of isolates were not susceptible to penicillin (with 61% being intermediate and 11% being resistant) and 92% were resistant to erythromycin. Telithromycin MICs were >or=1 microg/ml for 16% of the isolates, and for 99% of these isolates the MICs of all macrolides tested were >or=256 microg/ml; all of these isolates had the constitutive macrolide-lincosamide-streptogramin B phenotype. Eighty-eight percent of the isolates were resistant to three or more classes of drugs. The ciprofloxacin MICs were >or=4 microg/ml for six (0.6%) isolates from five patients collected in 2000 and 2001, and the levofloxacin MICs were >or=8 microg/ml for five of these isolates. Seven isolates for which ciprofloxacin MICs were >or=4 microg/ml, including one isolate recovered in 1999, belonged to three serotypes (serotype 19F, five isolates; serotype 23A, one isolate; and serotype 23B, one isolate). The isolates from the six patients for which ciprofloxacin MICs were >or=4 microg/ml had different pulsed-field gel electrophoresis profiles and random amplified polymorphic DNA patterns, indicating that no clonal dissemination occurred over this time period. Despite the increased rate of fluoroquinolone use, the proportion of pneumococcal isolates for which ciprofloxacin MICs were elevated (>or=4 microg/ml) remained low. However, the occurrence of telithromycin resistance is impressive and raises concerns for the future.

Adult↗

PubMed2003

Telithromycin and quinupristin-dalfopristin resistance in clinical isolates of Streptococcus pyogenes: SMART Program 2001 Data.

This study evaluated the current status of antimicrobial resistance in clinical isolates of Streptococcus pyogenes in Taiwan as part of the SMART (Surveillance from Multicenter Antimicrobial Resistance in Taiwan) program. In 2001, 419 different isolates of S. pyogenes, including 275 from respiratory secretions, 87 from wound pus, and 31 from blood, were collected from nine hospitals in different parts of Taiwan. MICs of 23 antimicrobial agents were determined at a central location by the agar dilution method. All of the isolates were susceptible to penicillin (MIC at which 90% of the isolates were inhibited [MIC(90)], moxifloxacin > ciprofloxacin = levofloxacin = gatifloxacin > gemifloxacin) demonstrated potent activity against nearly all of the isolates of S. pyogenes tested. Thirty-two isolates (8%) were not susceptible to quinupristin-dalfopristin. Seventeen percent of isolates had telithromycin MICs of >or=1 microg/ml, and all of these isolates exhibited erythromycin MICs of >or=32 microg/ml. The high prevalence of resistance to telithromycin (which is not available in Taiwan) limits its potential use in the treatment of S. pyogenes infections, particularly in areas with high rates of macrolide resistance.

Anti-Bacterial Agents↗

PubMed2002

Antimicrobial susceptibility testing of Mycobacterium tuberculosis to first-line drugs: comparisons of the MGIT 960 and BACTEC 460 systems.

The reliability of the Mycobacteria Growth Indicator Tube (MGIT) 960 system for rapid antimicrobial susceptibility testing (AST) of Mycobacterium tuberculosis was evaluated. Forty-seven isolates, including 10 fully susceptible and 37 resistant strains, were tested for susceptibility to the critical concentrations of streptomycin (STR), isoniazid (INH), rifampin (RMP), and ethambutol (EMB), as recommended by the manufacturer. Strains resistant to the critical concentrations were tested with higher concentrations. The results were compared to those obtained by a radiometric method (BACTEC 460TB) and by a conventional agar dilution method, which served as the reference method. Based on these data, we suggest that the following antibiotic concentrations give satisfactory results with the MGIT 960 system: STR, 4.0 microg/ml; INH, 0.1 microg/ml; RMP, 1.0 microg/ml; and EMB, 5.0 microg/ml. The time required to obtain susceptibility results averaged 6.9 days by the MGIT 960 system and 5.4 days by the BACTEC 460TB system; these intervals were not significantly different. This study shows that the MGIT 960 system is a reliable, rapid, automated method for testing the susceptibility of M. tuberculosis isolates to first-line drugs.

Antitubercular Agents↗

PubMed2002

A pilot study of oral fleroxacin once daily compared with conventional therapy in patients with pyogenic liver abscess.

The object of this open-label, randomized, comparative study was to evaluate the efficacy and safety of fleroxacin versus conventional therapy (cefazolin plus gentamicin/cephalexin) in the treatment of patients with bacterial liver abscess. Thirty-one adult patients (26 men and 5 women) received fleroxacin 400 mg orally once daily for 3 weeks, and 30 adult patients (21 men and 9 women) received conventional therapy for 3 to 4 weeks. Patients was assessed on day 3 of treatment, thereafter every week during treatment, and at 7 to 14 days (compulsory follow-up) after treatment for assessment of bacteriologic, clinical, and safety parameters. A total of 20 patients in the fleroxacin group and 22 patients in the conventional therapy group were evaluated. Klebsiella pneumoniae was the predominant pathogen isolated in all evaluable cases. Bacteriologic cure was achieved in 14 (70%) of 20 patients on fleroxacin therapy compared with 18 (81.8%) of 22 patients on conventional therapy (p=0.48). Clinical cure was achieved in 12 (60%) and 18 (81.8%) patients, and improvement in 2 (10%) and 1 (4.5%) patients in the fleroxacin and conventional therapy group, respectively. Most of adverse effects were of mild intensity. Oral fleroxacin once-daily administration is an effective, alternative treatment of bacterial liver abscess.

Administration, Oral↗