PubMed Health⌕ Search

Biomedical subjects

W K Huang

Publications and source records attributed to W K Huang.

At least 19 recordsLinked to original sources

Endoscopic 13C-urea breath test for the diagnosis of Helicobacter pylori infection.

BACKGROUND: Endoscopic 13C-urea breath test may avoid contamination of oral urease and rapidly discriminate Helicobacter pylori-positive and Helicobacter pylori-negative patients. AIMS: To compare the accuracy of endoscopic 13C-urea breath test with conventional invasive methods in diagnosis of Helicobacter pylori infection. PATIENTS: One hundred patients who attended for routine upper gastrointestinal endoscopy were included. METHODS: 13C-urea was applied to the stomach through the working channel of endoscope at the end of endoscopic examination. Breath samples were collected before endoscopy and 2, 4, 6, 8, 10 min after consumption of 100 or 50 mg 13C-urea. Helicobacter pylori infection was defined as those with positive culture or positive results of both histology and CLO test. RESULTS: The accuracy of 100 mg endoscopic 13C-urea breath test was significantly higher than that of culture and CLO test (100% vs. 88% and 92%, p = 0.02 and 0.03, respectively). The accuracy of 50 mg endoscopic 13C-urea breath test was higher than that of histology and CLO test (98% vs. 90% and 96%, respectively), although the differences were not statistically significant. CONCLUSIONS: Endoscopic 13C-urea breath test has a higher accuracy compared with biopsy-based modalities. It may be a good choice to diagnose Helicobacter pylori infection if endoscopy is indicated for a dyspeptic patient.

Adult↗

Inappropriate use of antibiotics and the risk for delayed admission and masked diagnosis of infectious diseases: a lesson from Taiwan.

BACKGROUND: Antibiotic resistance is a serious problem worldwide. It is particularly alarming in Taiwan and other countries of the Pacific Rim, where antimicrobial drugs are used excessively. OBJECTIVE: To determine whether use of antimicrobial drugs before coming to an emergency department was associated with delayed admission or masked or missed diagnoses at a large general hospital in Taiwan. METHODS: Antimicrobial activity in urine (AAU) was determined in all patients seen in the emergency department during a 3-month study. A physician, unaware of the results of the urine tests, reviewed the medical charts of patients who were admitted to the hospital to determine whether admission was delayed for at least 7 days or the diagnosis was masked or missed. RESULTS: Of the 1182 patients, 444 were admitted to the hospital. In 220 patients (49.5%), AAU was detected. There was no significant difference in AAU between patients with or without an infectious disease (53.0% vs 46.3%, respectively; P =.41). For patients with infection, 34.8% of those with AAU had a delayed admission, compared with only 21.6% without AAU (relative risk [RR], 1.61; 95% confidence interval [CI], 1.03-2.52; P =.03). For patients without infection, 36.2% of those with AAU had a delayed admission compared with 31.1% without AAU (RR, 1.16; 95% CI, 0.81-1.68; P =.64). For patients with infection, 48.7% of those with AAU had a masked or missed diagnosis, compared with 25.5% without AAU (RR, 1.91; 95% CI, 1.30-2.80; P<.001). For patients without infection, 27.6% of those with AAU had a masked or missed diagnosis compared with 14.8% without AAU (RR, 1.87; 95% CI, 1.11-3.17; P =.02). CONCLUSION: Use of antimicrobial drugs before coming to an emergency department was associated with a significantly increased risk for delayed and masked or missed diagnoses of infectious diseases and missed diagnosis of noninfectious diseases.

Adolescent↗

Clinical significance of oral urease in diagnosis of Helicobacter pylori infection by [13C]urea breath test.

This study was performed to evaluate the effect of oral flora on [13C]urea breath test in detecting H. pylori infection and find an optimal method and timing for sample collection. Forty-five volunteers were included in this study. The [13C]urea breath test was performed using mouthwash, endoscopic administration, and conventional methods. According to the receiver-operating characteristic curves, the earliest optimal time for discriminating H. pylori-positive and H. pylori-negative patients was at 25 min with the mouthwash method with 78% sensitivity and 82% specificity, at 2 min with the endoscopic administration method with 100% sensitivity and 100% specificity, and at 6 min with the conventional method with 100% sensitivity and 95% specificity. The study shows a significant effect of oral urease on the results of the [13C]urea breath test. The timing of sampling collection can be shortened to 6 min with the conventional method or to 2 min through endoscopic administration.

Adult↗

Multicenter surveillance of antimicrobial resistance of major bacterial pathogens in intensive care units in 2000 in Taiwan.

A susceptibility surveillance study of 1,274 bacterial isolates recovered from various clinical specimens from patients in intensive care units (ICUs) of five major teaching hospitals was carried out from March, 2000, to June, 2000, in Taiwan. This study demonstrated a high rate (66%) of oxacillin resistance in Staphylococcus aureus (ORSA), a high rate of nonsusceptibility to penicillin (intermediate, 50% and highly resistant, 8%), and high rates of cefotaxime nonsusceptibility for S. pneumoniae (intermediate, 29% and resistant, 4%), Enterobacter cloacae (57%), Serratia marcescens (34%), and Citrobacter freundii (60%). High rate of ceftazidime nonsusceptibility for Pseudomonas aeruginosa (22%), and high rates of imipenem nonsusceptibility for P. aeruginosa (15%) and Acinetobacter baumannii (22%) were also found. The percentage (11.9%) of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli was greater than that (11.3%) for Klebsiella pneumoniae. Rates of quinupristin-dalfopristin nonsusceptibility for S. pneumoniae (42%), Enterococcus faecium (71%), and ORSA (39%) were high, but no vancomycin-resistant enterococci were found in this study. The resistance rates of some pathogen varied by institution or type of ICUs. Surveillance for antimicrobial resistance among bacterial pathogens in hospitals, particularly in ICU settings with a preexisting higher resistance burden, is mandatory in establishing and/or modifying guidelines for empirical treatment of severe infections in ICU patients caused by these antimicrobial-resistant pathogens.

Bacteria↗

Comparison of the BACTEC MGIT 960 and BACTEC 460TB systems for detection of mycobacteria in clinical specimens.

The reliability of the Mycobacteria Growth Indicator Tube (MGIT) 960 system for rapid detection of mycobacteria in clinical specimens was evaluated and compared to the radiometric method (BACTEC 460TB) and to mycobacterial culture on Lowenstein-Jensen (LJ) medium. Clinical specimens (n = 590) were tested without selection. A total of 121 (20.5%) isolates of mycobacteria were recovered; 98 (81.0%) of them were recovered with the BACTEC 460TB system, 86 (71.1%) were recovered with the BACTEC MGIT 960 system, and 55 (45.5%) were recovered with LJ medium (MGIT 960 versus BACTEC 640TB, p >0.05; MGIT 960 or BACTEC 460TB versus LJ, p <0.001). The mean time to detection (TTD) was 18 da for BACTEC 460 TB, and 13 da for BACTEC MGIT 960. The mean time to detection in each system, based upon data where both systems were culture positive, was significantly different (16.6 da for BACTEC 460TB and 13 da for BACTEC MGIT 960, p<0.001). The contamination rate of the BACTEC MGIT 960 system was 13.2%, which was intermediate between the BACTEC 460TB system (11.7%) and the LJ medium (14.7%). These data indicate that the fully automated MGIT 960 system is an accurate, non-radiometric alternative to the BACTEC 460TB method for rapid detection of mycobacteria in a clinical setting.

Bacteriological Techniques↗

Follow-up of Helicobacter pylori status by using 13C-urea breath test in nonulcer dyspeptic patients after eradication therapy.

BACKGROUND: The role of eradication therapy is still controversial in H. pylori-related nonulcer dyspepsia (NUD). The aim of this study was to follow up the H. pylori status after eradication therapy in patients with NUD by using l3C-urea breath test (UBT). METHODS: Patients with a clinical and endoscopic diagnosis of NUD were included. H. pylori infection was established by endoscopic biopsies and 13C-UBT. Patients with H. pylori infection then received a quadruple therapy with colloidal bismuth subcitrate, metronidazole, tetracycline and lansoprazole. Two months after completion of therapy, endoscopic biopsies and 13C-UBT were performed again to confirm eradication. A follow-up 13C-UBT was carried out again in one year to detect recurrence of H. pylori infection. RESULTS: Eighty-eight of the 148 patients (59.5%) were found to have H. pylori infection by both endoscopic biopsies and 13C-UBT. Anti-H. pylori therapy was given for 55 patients and proved successful in 33 of them two months after the end of therapy. However, recurrence was found one year later in three of these 33 cases, making a recurrence rate of 9.1% (3/33). Three of the 22 cases with unsuccessful eradication were found to have H. pylori eradication at one year by follow-up 13C-UBT. One of the 33 H. pylori-positive patients without anti-H. pylori therapy, who had negative 13C-UBT in one year follow-up, was found taking a high dose and long period of antibiotics. CONCLUSIONS: The recurrence rate of H. pylori infection in our study was higher than that in the Western population. Delayed eradication of H. pylori may occur after anti-H. pylori therapy. Spontaneous eradication is rare in patients not receiving anti-H. pylori eradication.

Breath Tests↗

A 15-minute [13C]-urea breath test for the diagnosis of Helicobacter pylori infection in patients with non-ulcer dyspepsia.

BACKGROUND: Non-ulcer dyspepsia (NUD) accounts for the majority of dyspeptic patients and studies on the epidemiology of Helicobacter pylori infection in NUD depend on a non-invasive and rapid diagnostic test. This study was performed to determine the sensitivity and specificity of a 15-min simplified protocol of the [13C]-urea breath test ([13C]-UBT) for the diagnosis of H. pylori infection in patients with NUD. METHODS: One hundred and thirty-six patients with a clinical and endoscopic diagnosis of NUD were included. The [13C]-UBT was modified from the European standard protocol. The baseline breath sample was collected 5 min after the patient took a test meal and the 13CO2 was collected 15 min after the patient drank 100 mg [13C]-urea. The gold standard used for comparison was either a positive culture or positive histology + positive rapid urease test sampled on upper gastrointestinal endoscopy. RESULTS: The prevalence of H. pylori infection in NUD by the gold standard was 59.6%, whereas that calculated by the [13C]-UBT was 60.3%. The sensitivity and specificity of [13C]-UBT was 93.8 and 89.1% compared with the gold standard. The shortened collection time and simplification of the procedure may have led to a decline in specificity. CONCLUSION: The 15-min [13C]-UBT is a rapid but less specific protocol for detecting the presence of H. pylori infection in patients with NUD.

Adolescent↗

Extent of antibiotic use in Taiwan shown by antimicrobial activity in urine.

Taiwan has high prevalence of antibiotic resistant, community-acquired respiratory pathogens. We investigated whether there was a high frequency of antibiotic use in the community. Antimicrobial activity in urine was detected in 55.2% of 1182 patients on arrival at an emergency department, 25.1% of 203 internal medicine out-patients, 7.6% of 471 high school students, and 7.4% of 202 people at a centre for senior citizens.

Adolescent↗

Detection of antimicrobial activity in urine for epidemiologic studies of antibiotic use.

Antibiotic resistance is the inevitable consequence of the selective pressure of antimicrobial drug use and the adaptive plasticity of the microorganisms. Excessive and irrational use of antimicrobial drugs is a problem in all countries. It is particularly troublesome in developing countries where there is a heavy burden of infectious diseases. This study was designed to determine whether detection of antimicrobial activity in the urine might be a useful tool for epidemiologic studies of the interaction between antibiotic use and resistance in developing countries. A laboratory marker is necessary because the history of antimicrobial drug use may be unreliable. Serial specimens or spontaneously voided urine were obtained from healthy volunteers given a single oral dose of commonly used antimicrobial drugs. Urine was also obtained from hospitalized patients the morning after the last dose of an antimicrobial drug and from untreated controls. Assays were performed with standard American Type Culture Collection (Rockville, MD) stains of Bacillus stearothermophilus, Escherichia coli, and Streptococcus pyogenes. Antimicrobial activity could not be detected in pretreatment urine. After a single oral dose, the beta lactam antibiotics and erythromycin could be detected for about 12 to 24 hours, whereas clindamycin, tetracycline, trimethoprim/sulfamethoxazole, and ciprofloxacin could be detected for 48 or more hours. In hospitalized patients, receiving multiple drugs, the following were the sensitivity and specificity for detection of antimicrobial activity: for B. stearothermophilus, 100.0% and 85.9%, respectively; for S. pyogenes, 94.9% and 94.9%, respectively; and for E. coli, 71.8% and 98.7%, respectively. The combination of E. coli and Streptococcus pyogenes exhibited a sensitivity of 97.4% and specificity of 94.9%. Detection of antimicrobial activity in urine is a promising method to determine antimicrobial drug use in epidemiologic studies, particularly in populations in which drug use history is unreliable.

Adult↗

Comparison of a nonradiometric liquid-medium method (MB REDOX) with the BACTEC system for growth and identification of mycobacteria in clinical specimens.

Early identification of tuberculosis in the clinical setting is of great importance in order for specific therapy to be swiftly initiated. MB REDOX (Heipha Diagnostika), a growth-based medium without radioactive materials, was evaluated and was compared to the BACTEC system for detection of mycobacteria, including the Mycobacterium tuberculosis complex and atypical mycobacteria. MB REDOX consists of a Kirchner medium enriched with growth-promoting additives, antibiotic compounds, and a redox indicator which can be monitored to detect growth of mycobacteria with the naked eye. MB REDOX only detects growth and cannot differentiate the M. tuberculosis complex (M. tuberculosis, M. bovis, and M. africanum) from other species of Mycobacterium. Therefore, PCR-restriction fragment length polymorphism analysis (PRA) was used in this investigation to identify to the species level organisms showing positive growth with MB REDOX. Our data demonstrate the usefulness of MB REDOX for the detection of mycobacteria in clinical specimens. The rate of detection of M. tuberculosis complex with MB REDOX (84. 3%) was higher than that with the BACTEC system (68.6%). When combined with PRA for species identification, MB REDOX is easy to perform and is suited to most clinical laboratory settings for the detection and identification of mycobacteria.

Bacteriological Techniques↗

Line probe assay for rapid detection of mutations in the rpoB gene of Mycobacterium tuberculosis.

Detection of mutations in the rpoB gene of Mycobacterium tuberculosis has been reported to be an accurate predictor of rifampin resistance. DNA sequence analysis and screening methods such as single-strand conformation polymorphism analysis and dideoxy fingerprinting are labor-intensive, expensive, or yield results that may prove difficult to interpret. We evaluated the accuracy of a commercial line probe assay for rapid identification and characterization of mutations in the rpoB gene in 72 isolates of M. tuberculosis, including 50 rifampin-resistant and 22 rifampin-susceptible strains. Ten distinct rpoB mutations were identified. Concordances with automated sequencing results and phenotypic rifampin susceptibility testing results were 99% and 93%, respectively. The results demonstrate the line probe assay to be a rapid (as short as 1 day) and informative tool for the early detection and characterization of rpoB mutations associated with rifampin resistance in a clinical laboratory setting.

Antibiotics, Antitubercular↗

Dideoxy fingerprinting for rapid screening of rpoB gene mutations in clinical isolates of Mycobacterium tuberculosis.

Rifampin is a key component of therapeutic regimens for tuberculosis control, and a marker for multidrug resistance of Mycobacterium tuberculosis. Mutations responsible for conferring rifampin resistance in M. tuberculosis are known to occur in a 69-bp region of the rpoB gene. In this study, we assessed the accuracy of dideoxy fingerprinting (ddF), a hybrid technique employing elements of dideoxy sequencing and single-strand polymorphism analysis, for rapid screening of rifampin resistance in clinical isolates of M. tuberculosis. This technique was used to analyze 72 M. tuberculosis isolates. The results were compared with those of automated dideoxy sequencing and the antibiotic resistance profile (determined with the BACTEC system). Of the 72 isolates, 50 were rifampin resistant. The ddF findings were completely consistent with those of dideoxy sequencing in all isolates. In 68 (94%) isolates, the ddF findings were consistent with the rifampin resistance status determined with the BACTEC system; all four isolates with inconsistent results had no mutation in the 69-bp region, but were resistant to rifampin. Our findings suggest that ddF accurately detects mutations in the rifampin resistance-associated 69-bp region of the rpoB gene in clinical isolates of M. tuberculosis, and may be a valuable screening tool for rifampin resistance.

DNA Fingerprinting↗

Correlation of serum immunoglobulin G Helicobacter pylori antibody titers with histologic and endoscopic findings in patients with dyspepsia.

Serum immunoglobulin G (IgG) antibody tests are used extensively. We attempted to find out whether the titers of anti-Helicobacter pylori IgG antibody correlated with the degree of macroscopic gastrointestinal damage, the severity of antral gastritis, and the density of antral H. pylori colonization in symptomatic patients. Peripyloric antral biopsy specimens were obtained from 50 consecutive patients with dyspepsia undergoing upper gastrointestinal endoscopy. The macroscopic gastrointestinal damage and the histologic grades of antral gastritis were scored by a modified Lanza scale and Sydney system, respectively. In addition, the densities of antral H. pylori colonization were graded semiquantitatively. Serum IgG antibodies to H. pylori were measured by enzyme-linked immunosorbent assay. Thirty-six (M/F = 29/7) of the 50 patients had H. pylori infection documented by histologic examination or rapid urease test or both. Among the subjects, the IgG antibody titers to H. pylori correlated significantly with the grades of antral polymorphonuclear cell infiltration (p = 0.002) and antral bacterial density (p = 0.01) but not with endoscopic scores, the grades of mononuclear cell infiltration, mucosal atrophy, or intestinal metaplasia (p > 0.05). In addition, endoscopic scores also were found to be significantly correlated with antral bacterial density (p = 0.049) and the grade of polymorphonuclear cell infiltration (p = 0.012). We therefore conclude that high titers of IgG antibody to H. pylori in patients with dyspepsia indicate dense H. pylori colonization and severe antral polymorphonuclear cell infiltration. However, it cannot replace endoscopic examination to evaluate the degree of macroscopic gastrointestinal damage.

Aged↗

Comparison of the Roche AMPLICOR MYCOBACTERIUM assay and Digene SHARP Signal System with in-house PCR and culture for detection of Mycobacterium tuberculosis in respiratory specimens.

Two commercial primer kits and detection systems, the Roche AMPLICOR MYCOBACTERIUM test and the Digene primer-probe kit with the SHARP Signal System, were compared to in-house PCR as well as standard culture techniques. For the 27 culture-positive specimens, the Roche AMPLICOR MYCOBACTERIUM test detected 20 specimens, the Digene system detected 19, and in-house PCR detected 21. Of the 86 culture-negative specimens, 13 were positive by the Roche AMPLICOR MYCOBACTERIUM test, 16 were positive by the Digene system, and 21 were positive by in-house PCR. When clinical situations were evaluated, 11 of 13 culture-negative Roche AMPLICOR MYCOBACTERIUM test-positive specimens, 10 of 16 culture-negative Digene system-positive specimens, and 13 of 21 culture-negative-in-house PCR-positive specimens were diagnosed as true-positive specimens. The sensitivities of Roche AMPLICOR MYCOBACTERIUM test, the Digene system, and in-house PCR were 73.81, 69.05, and 80.95%, and the specificities were 97.18, 91.55 and 88.73%, respectively. The positive predictive values were 93.94, 82.86, and 80.95%, and the negative predictive values were 86.25, 83.33, and 88.73%, respectively. For the commercial kits, the Roche AMPLICOR MYCOBACTERIUM test seems to be more sensitive and specific than the Digene system. However, the Roche AMPLICOR MYCOBACTERIUM test cannot be used on nonrespiratory specimens.

Bacteriological Techniques↗

[Laboratory evaluation of automated enzyme linked fluorescent assay for detecting serum specific IgG antibodies against rubella virus].

The VIDAS rubella IgG(RBG) is a new, automated, enzyme-linkad fluorescent assay(ELFA) for detecting IgG antibodies to rubella virus in serum. The purpose of this study was to evaluate the usefulness of the qualitative and quantitative VIDAS RBG as laboratory tests in the rapid detecting anti-rubella IgG antibodies. Simultaneous parallel testing was performed by using the qualitative and quantitative RBG along with RUBAZYME(ABBOTT LABORATORIES) and the standard hemagglutination-inhibition(HI) test(R-HI kit, SEIKEN) on 200 blood samples submitted for anti-rubella IgG antibodies testing from patients at the VGH-Kaohsiung(Mar.-Sep., 1993). The qualitative and quantitative VIDAS RBG and RUBAZYME assay were compared to the standard R-HI test. Significant differences among the sensitivities of these three methods were found (100% sensitivity for the qualitative VIDAS RBG, 88.89% for the quantitative VIDAS RBG and 97.67% for the RUBAZYME). However, the specificities of these three methods were all the same, 100%. With these results we can conclude that the qualitative VIDAS RBG will provide a very good, precise and reliable method to determine serum specific IgG antibodies against rubella virus. Furthermore, the VIDAS RBG is fully automated and time-saving procedures (for every batch of test, it takes 25 minutes with VIDAS RBG, 2.5 hours with RUBAZYME and 4.5 hours with R-HI) in clinical laboratories.

Antibodies, Viral↗

Evaluation of polymerase chain reaction-restriction enzyme analysis of mycobacteria cultured in BACTEC 12B bottles.

Polymerase chain reaction with restriction enzyme analysis (PRA) was first tested on 15 reference strains and 50 subcultured clinical isolates of mycobacteria according to the reference algorithm by Telenti et al [1]. Next, we evaluated the application of this method to 108 isolates from liquid media (BACTEC 12B). Of them, 15 M. tuberculosis complex and 81 mycobacteria other than tuberculosis (MOTT) had comparable results with both PRA and the BACTEC 460 TB systems. However, seven M. tuberculosis complex and three potentially pathogenic MOTT were identified by PRA rather than the BACTEC TB system. PRA seems to be an efficient method for the identification of mycobacteria to the species level and a good aid to detect potentially pathogenic mycobacteria, especially in mixed mycobacterial cultures.

Humans↗

Melioidosis: two indigenous cases in Taiwan.

We report the first two indigenously acquired cases of melioidosis in Taiwan, diagnosed by positive culture and biochemically identified using the ID 32 GN system (BioMerieux Vitek Inc, Hazelwood, MO, USA). The first patient was a 75-year-old Chinese woman who had not travelled abroad since her arrival from mainland China (San-Tung province) 47 years ago. She presented with spontaneous bacterial peritonitis and hepatitis C-related liver cirrhosis with septic shock. Burkholderia pseudomallei (formerly Pseudomonas pseudomallei) was isolated from cultures of both blood and ascites fluid. The second patient, a 70-year-old Chinese man, presented with right lower lobar pneumonia complicated with empyema and septic shock. Blood cultures grew B. pseudomallei. Both patients had underlying diabetes mellitus; one also had liver cirrhosis and chronic renal failure, while the other had a renal stone. The first patient died of refractory septic shock prior to diagnosis. The second patient survived with the use of intravenous ceftazidime for 30 days, followed by oral amoxicillin-clavulanic acid for a further 3 months. These cases serve as a reminder to clinical physicians that melioidosis is now no longer exclusive to patients with a history of travel to endemic areas. A high index of clinical suspicion is required for early diagnosis and treatment in order to reduce the mortality and improve clinical outcome.

Aged↗

Streptococcal toxic shock syndrome in southern Taiwan.

This report outlines our experience with streptococcal toxic shock syndrome (STSS) at the Veterans General Hospital-Kaohsiung during the period October 1990 to November 1993. Group A streptococci were isolated from blood or normally sterile tissue in association with hypotension and multi-organ failure in the eight cases studied. A primary focus of infection was identified in seven cases, including pneumonia (1), septic arthritis (1) and soft-tissue infections (5). The remaining patient suffered from hyperglycemic hyperosmolar non-ketotic coma and Group A streptococcal bacteremia, without an obvious focus of infection. There were four cases of bacteremia. Clinical complications included acute renal failure in all eight cases, disseminated intravascular coagulation in five cases, liver involvement in two cases, adult respiratory distress syndrome in one case and soft-tissue necrosis in five cases. All isolates were sensitive to penicillin, and most patients were treated with intravenous penicillin G, with or without other antibiotics (gentamicin or clindamycin). Of the six patients with soft-tissue infection, two underwent amputation of the infected limb, and one patient underwent sono-guided pigtail drainage of psoas muscle abscess. Three of the patients died. STSS may be uncommon in Taiwan, but it is not rare. Early recognition of STSS (facilitated by Gram stain and culture), prompt debridement and drainage, and adequate antibiotic treatment with penicillin or clindamycin, or both, are necessary for control of such lethal infections.

Adult↗