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Biomedical subjects

Po-Ren Hsueh

Publications and source records attributed to Po-Ren Hsueh.

At least 127 records · Page 7Linked to original sources
PubMed2004

SARS antibody test for serosurveillance.

A peptide-based enzyme-linked immunosorbent assay (ELISA) can be used for retrospective serosurveillance of severe acute respiratory syndrome (SARS) by helping identify undetected chains of disease transmission. The assay was developed by epitope mapping, using synthetic peptides from the spike, membrane, and nucleocapsid protein sequences of SARS-associated coronavirus. The new peptide ELISA consistently detected seroconversion by week 2 of onset of fever, and seropositivity remained through day 100. Specificity was 100% on normal blood donor samples, on serum samples associated with infection by other pathogens, and on an interference panel. The peptide-based test has advantages of safety, standardization, and automation over previous immunoassays for SARS. The assay was used for a retrospective survey of healthy healthcare workers in Taiwan who treated SARS patients. Asymptomatic seroconversions were detected in two hospitals that had nosocomial disease.

Antibodies, Viral↗
PubMed2004

Community-acquired methicillin-resistant Staphylococcus aureus in children in northern Taiwan.

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a well-recognized nosocomial infection of increasing incidence. Recent reports have also revealed an increment of community-acquired MRSA (CA-MRSA) infections in people without any risk factors. We reviewed the medical charts of 464 children with S. aureus infections presenting between January 1997 and August 2001, in order to understand the occurrence of CA-MRSA infections in children without any risk factors and to define the spectrum of disease. MRSA made up 74% of community-acquired S. aureus infections (59/80). Among them, patients without identifiable risk factors comprised 29 CA-MRSA infections (36%). The number of patients with CA-MRSA disease increased from 11 of 172 (6%) S. aureus infections between January 1997 and April 1999 to 48 of 292 (16%) between May 1999 and July 2001. Skin and soft tissue infections were the most common presentations of community-acquired S. aureus infections. Bacteremia was the major manifestation of nosocomial S. aureus infections, and osteomyelitis and bacteremia were not infrequently seen in patients with CA-MSSA infections. Only 13 out of 29 patients (45%) with CA-MRSA infections without risk factors received effective antibiotic therapy, while 16 cases were cured by either antibiotics without in vitro activity, or surgical drainage, or both. CA-MRSA isolates were more likely to be susceptible to minocycline, gentamicin, and trimethoprim-sulfamethoxazole, compared to hospital-acquired MRSA isolates. Our data suggest an increasing role of MRSA as a community pathogen in previously healthy children. Infection control strategies for both hospital and community should be re-evaluated.

Adolescent↗
PubMed2004

Bacteremic Streptococcus bovis infections at a university hospital, 1992-2001.

BACKGROUND AND PURPOSE: The association of Streptococcus bovis biotypes with types of clinical infection and underlying malignancies has rarely been reported in Taiwan. The aim of this study was to characterize the clinical features and microbiological characteristics of patients with S. bovis bacteremia. METHODS: From January 1992 to December 2001, 62 patients with S. bovis bacteremia were treated at National Taiwan University Hospital. Their demographic characteristics, clinical features, results of imaging studies, pathological findings, and laboratory data were retrospectively analyzed. Antimicrobial susceptibilities were determined using the agar dilution method and biotypes were determined using the API 20 Strep system. RESULTS: The majority of cases (76%) occurred during the 1996-1997 and 1999-2000 periods. Thirty five patients were male, and the mean age of the 62 patients was 61 years. Underlying diseases included malignancies (40%), cardiac diseases (27%), diabetes mellitus (24%), and liver cirrhosis (21%). Fifty two percent (n = 32) of patients presented with primary bacteremia and 24% (15) with definite or possible infective endocarditis. Thirteen percent (8) presented with hepatobiliary infections (acute cholecystitis and biliary tract infection). Ten patients (16%) had polymicrobial bacteremia. All of the concomitant pathogen(s) were Gram-negative rods, among which Escherichia coli predominated. The mortality rate on day 30 of illness was 21%. High Acute Physiology and Chronic Health Evaluation (APACHE) II score on the day of positive blood culture was associated with high mortality. Among the 19 patients (31%) who underwent colonoscopy, 9 (47%) had colonic lesions (tubular adenomas or carcinomas). Of the 26 patients (41%) who underwent echocardiography, 14 (54%) had vegetation in the valves. Of the 47 S. bovis isolates examined for biotypes, 37 (79%) were biotype II (29 of biotype II/2 and 8 of biotype II/1) and 10 (21%) were biotype I. The majority of isolates causing primary bacteremia (92%), hepatobiliary infections (100%) and primary bacterial peritonitis (100%) were biotype II, while 67% of isolates associated with infective endocarditis were biotype I. All isolates were susceptible to penicillin. CONCLUSIONS: Infective endocarditis should be highly suspected in patients with bacteremia due to S. bovis biotype I. Investigations for intra-abdominal foci other than the colon should be undertaken in patients with bacteremia caused by S. bovis biotype II. Due to the increasing number of S. bovis bacteremia patients at the hospital and unknown origins of about 50% of bacteremia cases, the need for colonoscopy and echocardiography in each case and biotyping of each blood isolate should be emphasized.

APACHE↗
PubMed2004

Trends and antimicrobial resistance of pathogens causing bloodstream infections among febrile neutropenic adults with hematological malignancy.

BACKGROUND AND PURPOSE: The microbiological spectrum in cancer patients with febrile neutropenia has changed over the past several decades in western countries. The growing incidence of antimicrobial resistance is an inevitable consequence of the widespread use of antibiotics in medical settings. The aim of this study was to clarify the trends and antimicrobial resistance among pathogens causing bloodstream infections in febrile neutropenic adults with hematological malignancies. METHODS: The characteristics of pathogens causing bloodstream infection isolated from patients with febrile neutropenia who were treated at National Taiwan University Hospital from 1996 to 2001 were reviewed. A total of 1174 pathogens were isolated from 3093 admissions to a hematological ward during this period. Among them, 738 isolates were recovered from patients with febrile neutropenia. RESULTS: The majority (93%) of these neutropenic febrile patients had underlying acute leukemia or lymphoma. Gram-negative bacteria accounted for 57% of isolated pathogens, followed by Gram-positive bacteria (32%), fungi (7%), and anaerobes (3%). In decreasing frequency, Escherichia coli (13%), Klebsiella pneumoniae (12%), Enterobacter cloacae (7%), Pseudomonas aeruginosa (6%), and Acinetobacter baumannii (5%) were the predominant Gram-negative bacteria, while coagulase-negative staphylococci (13%), viridans group streptococci (4%), and Staphylococcus aureus (4%) were the major Gram-positive pathogens. Two-thirds (20/30) of S. aureus isolates were resistant to oxacillin. No vancomycin-resistant enterococci were isolated. Resistance to cefotaxime was found in 63% of E. cloacae, 13% of K. pneumoniae and 10% of E. coli. Overall, 33% of E. coli and 13% of K. pneumoniae were resistant to ciprofloxacin. CONCLUSIONS: This study indicates that the microbiological spectrum of microorganisms causing bloodstream infections in neutropenic febrile patients with hematological malignancies at National Taiwan University Hospital is different from western countries in that Gram-negative bacteria remain the predominant pathogens. Antimicrobial resistance among these pathogens is high and E. coli and K. pneumoniae isolates with resistance to third-generation cephalosporins and ciprofloxacin are increasing.

Adult↗
PubMed2004

Species distribution and fluconazole susceptibility of Candida clinical isolates in a medical center in 2002.

Fluconazole disk-diffusion susceptibility was evaluated in 230 blood isolates and 344 non-blood clinical isolates of Candida spp. collected in 2002 at National Taiwan University Hospital. Up to 93.5% of blood isolates were susceptible to fluconazole, 3% were susceptible dose-dependent, and 3.5% were resistant. The minimum inhibitory concentrations at which 50% of tested isolates were inhibited (MIC50) of fluconazole against Candida blood isolates were highest for Candida glabrata (5 microg/mL), followed by Candida tropicalis (2.4 microg/mL), Candida albicans (2.4 microg/mL), and Candida parapsilosis (0.41 microg/mL). C. glabrata had less fluconazole-susceptible strains (76.7%) than C. albicans (98.2%), C. tropicalis (98%) and C. parapsilosis (93.8%) [p<0.05]. The proportions of fluconazole resistance in the non-blood isolates of C. albicans, C. glabrata and C. parapsilosis were similar to those of the blood isolates. However, the proportions of fluconazole resistance in the non-blood isolates of C. tropicalis surpassed those of the blood isolates (14.7% vs 2%, p<0.05). Comparison of species distribution of Candida blood isolates obtained in 2002 to those in 1981-2000 demonstrated that C. albicans remained the leading pathogen, and the proportion of C. albicans in blood isolates was lowest in 1996 (38%) and did not change significantly thereafter. However, the proportion of C. tropicalis increased from 14% during 1981-1993 to 22-23% during 1996-2002. Overall, the MIC50, MIC90 and the proportion of Candida blood isolates with fluconazole resistance remained stable during 1994-2002.

Antifungal Agents↗
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↗
PubMed2004

Drug resistance pattern of Mycobacterium tuberculosis in a university hospital in Taiwan, 1998-2002.

BACKGROUND AND PURPOSE: During 1998-2002, most specialized tuberculosis (TB) hospitals in Taiwan were closed; as a result, more TB patients are being managed in general hospital settings. This study investigated the prevalence, patterns and risk factors of drug-resistant Mycobacterium tuberculosis at a university hospital in the 5 years after decentralization of the TB administrative and clinical control infrastructure which occurred during the implementation of the national health insurance system in Taiwan. METHODS: A total of 1411 initial isolates of M. tuberculosis from specimens collected during January 1998 through December 2002 were tested for drug susceptibility of first-line anti-TB drugs using the agar proportional method. RESULTS: The numbers of newly diagnosed culture-positive TB patients increased from 139 in 1998 to 380 in 2002. The drug resistance pattern of M. tuberculosis among these isolates was as follows: 268 (19.0%) strains were resistant to isoniazid, 86 (6.1%) to rifampin, 221 (15.7%) to ethambutol, 141 (10.0%) to streptomycin, and 430 (30.5%) to 1 of these 4 drugs. Multidrug resistance (MDR), i.e., resistance to at least rifampin and isoniazid, was observed in 72 isolates (5.1%). Of the 1411 patients, isolates from patients with age < 65 years had a higher multiple drug resistance rate than those from patients with age > or = 65 years (57/781, 7.3% vs 15/630, 2.4%; p < 0.001). In the analysis of risk factors for MDR, patients with MDR isolates had a significantly higher incidence of previous TB history, anti-TB therapy, longer duration of symptoms, cavitary lesions in chest X-ray, and mortality. CONCLUSION: A dramatic increase in cases of TB among patients treated at this university hospital was seen after the decentralization of the TB control infrastructure in Taiwan. The prevalence of drug resistance in isolates from culture-positive TB patients was 30.5% and the prevalence of MDR was 5.1%.

Adult↗
PubMed2004

Nosocomial bloodstream infection in human immunodeficiency virus-infected patients in Taiwan: descriptive epidemiology and risk factors for mortality.

BACKGROUND AND PURPOSE: Nosocomial bloodstream infection (NBSI) is common in patients with human immunodeficiency virus (HIV) infection. This study evaluated the incidence, causative pathogens, and outcome of NBSIs in hospitalized HIV-infected patients at a university hospital in Taiwan. METHODS: The medical records of all HIV-infected patients who developed NBSIs from June 1994 to June 2003 were retrospectively reviewed. A standardized case record form was used to collect demographic, clinical, laboratory, and microbiologic data. RESULTS: During the study period, 57 episodes of NBSIs occurred in 51 HIV-infected patients whose median age was 37 years (range, 23 to 60 years). All of the patients were at HIV infection stage C. The incidence of NBSIs was 2.3 per 1000 person-days of hospitalization (41.4 per 1000 discharges). More than three-fourths of the 57 episodes (77.2%) were classified as primary NBSIs. Other infection foci included respiratory tract (6 episodes), urinary tract (3), surgical site (2), and skin (2). Staphylococcus species were the leading pathogens (42.1%). The crude and attributable mortality rates in patients with NBSIs during the study period were 38.6% and 26.1%, respectively. Multivariate analysis using a logistic regression model revealed that shock and hypoalbuminemia at the onset of NBSIs were the 2 factors predictive of mortality. CONCLUSIONS: NBSIs in hospitalized patients in the late stage of HIV infection were associated with a high attributable mortality rate. Staphylococcus species were the leading pathogen responsible for NBSIs. Presentations of shock and hypoalbuminemia were predictive of mortality.

AIDS-Related Opportunistic Infections↗
PubMed2004

Genetic detection of diarrheagenic Escherichia coli isolated from children with sporadic diarrhea.

Escherichia coli strains are among the major bacterial causes of diarrheal illness. At least 5 categories of diarrheagenic E. coli (DEC) are recognized, namely enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), and enterohemorrhagic E. coli (EHEC). Due to the need for costly and labor-intensive diagnostic procedures, identification of DEC is difficult at standard laboratories. Therefore, the epidemiology of DEC infections remains obscure in Taiwan. Recently, polymerase chain reaction (PCR) or dot blot has been used for genetic detection of DEC. In this study, we analyzed 150 E. coli isolates from diarrheal stools of children under 5 years old. The PCR tests detected 5 ETEC (3.3%), 6 EPEC (4%), 4 EIEC (2.7%), and 13 EAEC (8.7%) isolates. No EHEC was detected. Dot blot and sequence analysis were used to confirm the results of PCR. The cellular fatty acid (CFA) profiles from E. coli isolates were also analyzed. Comparison of CFA composition revealed minor variation in the percentage of each fatty acid detected among DEC isolates of ETEC, EPEC, EIEC and EAEC, but did not provide enough evidence for differentiating between categories of DEC by CFA profiles alone.

Base Sequence↗
PubMed2004

Bacteremic necrotizing fasciitis caused by Vibrio cholerae serogroup O56 in a patient with liver cirrhosis.

Bacteremic necrotizing fasciitis caused by non-O1 Vibrio cholerae has rarely been reported. We describe a case of necrotizing fasciitis of the bilateral lower extremities in a 68-year-old man with liver cirrhosis and diabetes mellitus. Cultures of blood and the debrided tissue all yielded V. cholerae serogroup non-O1 (O56). Despite extensive radical debridement and antibiotic treatment with ceftazidime and doxycycline, the patient died on the 12th hospital day due to multiple organ failure. The present case is the first report of necrotizing fasciitis and bacteremia caused by V. cholerae serogroup O56.

Aged↗
PubMed2003

Clinical and microbiological characteristics of Rhizobium radiobacter infections.

Data obtained from 1996 to 2002 on 13 patients with Rhizobium radiobacter infections were analyzed. Ten patients (76%) had underlying hematological malignancy or solid-organ cancer. Six patients (46%) had febrile neutropenia during the course of R. radiobacter infection. The majority (54%) of infections were catheter-related bacteremia, and 92% of infections were hospital acquired. All the patients survived. Eighteen isolates were recovered from the 13 patients, and each isolate was susceptible to cefepime, piperacillin-tazobactam, carbapenems, and ciprofloxacin. The pulsed-field gel electrophoresis profiles differed among the isolates recovered from different patients, indicating the absence of nosocomial spread of the organism.

Adolescent↗
PubMed2003

High prevalence of antimicrobial resistance in rapidly growing mycobacteria in Taiwan.

An increasing number of clinical isolations of rapidly growing mycobacteria (RGM) at the National Taiwan University Hospital were noted from 1992 to 2001. Broth microdilution MICs of 15 antimicrobial agents were determined for 200 clinical isolates of RGM, including the Mycobacterium fortuitum group (69 isolates), M. chelonae (39 isolates), and M. abscessus (92 isolates). Our results showed that the resistance rates of these isolates to the currently available agents were remarkably high. Amikacin was active against nearly all RGM isolates. Clarithromycin was usually active against M. abscessus (79% susceptibility) and the M. fortuitum group (65% susceptibility). The majority of M. fortuitum group isolates were susceptible to ciprofloxacin (62%) and imipenem (61%). The susceptibilities to other conventional anti-RGM agents of these isolates were poor but differed markedly by species. The newer fluoroquinolones (levofloxacin, moxifloxacin, and gatifloxacin) and meropenem showed better in vitro activities against the M. fortuitum group isolates than against the other two species of RGM. Linezolid had fairly good activity against these RGM isolates, particularly against M. chelonae isolates (82% susceptible). Telithromycin had poor activity against these RGM isolates (the MICs at which 50% of the isolates tested are inhibited [MIC(50)s] were 32 to 64 microg/ml, and the MIC(90)s were >64 microg/ml).

Anti-Bacterial Agents↗
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↗
PubMed2003

Catheter-related sepsis due to Rhodotorula glutinis.

We describe a central venous catheter-related (Port-A-Cath; Smiths Industries Medical Systems [SIMS] Deltec, Inc., St. Paul, Minn.) infection caused by Rhodotorula glutinis in a 51-year-old man with nasopharyngeal carcinoma. He was treated with fluconazole for 8 weeks and had the catheter removed. Two isolates of R. glutinis recovered from blood specimens (one obtained via peripheral veins and one via the catheter) before administration of fluconazole and one recovered from the removed catheter 17 days after initiation of fluconazole therapy exhibited high-level resistance to fluconazole (MICs, >256 microg/ml). These three isolates were found to belong to a single clone on the basis of identical antibiotypes determined by the E test (PDM Epsilometer; AB Biodisk, Solna, Sweden) and biotypes determined by API ID32 C (bioMerieux, Marcy I'Etoile, France) and their identical random amplified polymorphic DNA patterns.

Antifungal Agents↗
PubMed2003

Microbiologic characteristics, serologic responses, and clinical manifestations in severe acute respiratory syndrome, Taiwan.

The genome of one Taiwanese severe acute respiratory syndrome-associated coronavirus (SARS-CoV) strain (TW1) was 29,729 nt in length. Viral RNA may persist for some time in patients who seroconvert, and some patients may lack an antibody response (immunoglobulin G) to SARS-CoV <21 days after illness onset. An upsurge of antibody response was associated with the aggravation of respiratory failure.

Adult↗