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Biomedical subjects

Po-Ren Hsueh

Publications and source records attributed to Po-Ren Hsueh.

At least 145 records · Page 8Linked to original sources
PubMed2003

Peritonitis caused by Chryseobacterium meningosepticum in a patient undergoing continuous ambulatory peritoneal dialysis.

Chryseobacterium meningosepticum is rarely encountered as a pathogen causing peritonitis in adults. A 54-year-old woman who underwent continuous ambulatory peritoneal dialysis for 8 years developed peritonitis due to C. meningosepticum. Although she received intravenous antibiotics with good in vitro activity against the organism, the fever and signs of peritonitis persisted. The Tenckhoff catheter was finally removed on the 25th day of hospitalization and the fever subsided. Four isolates of C. meningosepticum recovered from 4 ascites samples drawn on the third, 13th, 18th, and 23rd hospitalization days had identical antibiograms and random amplified DNA polymorphism patterns generated by an arbitrarily primed polymerase chain reaction. Early removal of Tenckhoff catheter and appropriate antimicrobial therapy are crucial to the successful treatment of peritonitis due to C. meningosepticum.

Catheters, Indwelling↗
PubMed2003

Association of antibiotic utilization measures and reduced incidence of infections with extended-spectrum beta-lactamase-producing organisms.

With the overuse of expanded-spectrum cephalosporins, especially ceftazidime, outbreaks of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae and Escherichia coli infections have been reported. In this prospective observational study, we demonstrated that the addition of piperacillin/tazobactam to the formulary and the restriction of ceftazidime were associated with a decrease in the percentage of ceftazidime-resistant isolates. When the use of ceftazidime decreased by 96.43%, and the use of piperacillin/tazobactam increased by over 50% during the 9-month study period, a concomitant decrease was found in the percentage of colonization and infection by ESBL-producing E. coli or K. pneumoniae in patients admitted to the intensive care unit. Results from this 9-month intervention study support the concept that levels of local and institutional use of ceftazidime are of substantial importance to the emergence and persistence of endemic ceftazidime-resistant K. pneumoniae.

Anti-Bacterial Agents↗
PubMed2003

Bacteremia in hematological and oncological children with febrile neutropenia: experience in a tertiary medical center in Taiwan.

A retrospective study of bacteremia in children with febrile neutropenia admitted to a medical center in Taiwan from January 1999 to December 1999 was performed. There were 190 episodes of febrile neutropenia during this period and 46 pathogens were isolated from blood specimens in 38 bacteremic episodes (7 mixed infections). Pseudomonas aeruginosa (17.4%), Staphylococcus aureus (10.9%), Klebsiella pneumoniae (10.9%), and Enterobacter cloacae (10.9%) were the most common isolates. Three of the 5 isolates of S. aureus were resistant to methicillin. Twenty-three episodes of bacteremia (four mixed infections) were associated with recent antibiotic use. Of the 23 bacteremic episodes with recent antibiotic use, P. aeruginosa (20%), methicillin-resistant S. aureus (10%), K. pneumoniae (10%), Escherichia coli (10%), and E. cloacae (10%) were isolated most often. Relapsed leukemia (odds ratio 3, 95% confidence interval 1.4-6.5) and recent antibiotic therapy (odds ratio 3.4, 95% confidence interval 1.7-7.7) were the independent risk factors of bacteremia. There were 9 mortality cases in patients with bacteremia, including 4 cases with mixed infections, and 5 cases with P. aeruginosa, E. coli, Klebsiella oxytoca, S. aureus, and Streptococcus mitis, respectively. Broad-spectrum antibiotics were necessary in febrile neutropenic children because of the high percentage of mixed infection.

Academic Medical Centers↗
PubMed2003

Clinical features of pandrug-resistant Acinetobacter baumannii bacteremia at a university hospital in Taiwan.

BACKGROUND AND PURPOSE: The number of infections caused by Acinetobacter baumannii has increased in recent years and the emergence of pandrug-resistant A. baumannii (PDRAB) has been observed in Taiwan. The aim of this study was to evaluate the clinical features and outcomes of patients with bacteremia due to PDRAB. METHODS: From January 1999 to April 2002, 30 patients with PDRAB bacteremia were treated. We analyzed the clinical characteristics of these patients, including gender, underlying diseases, clinical manifestations, antibiotic treatment, and outcome. RESULTS: Bacteremia developed an average of 33 days after hospitalization and was hospital acquired in all cases. The source of bacteremia was identified in 19 patients (63.3%) and was most commonly from the respiratory tract. The overall mortality was 60% (18 patients). Among these, the cause of death was directly related to PDRAB bacteremia in 12. Underlying heart disease, shock, resuscitation, acute respiratory distress syndrome, mechanical ventilation, and multiple organ dysfunction score (MODS) were significant predictors of mortality after the development of PDRAB bacteremia. No specific antimicrobial therapy appeared to be effective. CONCLUSIONS: Clinical outcomes of patients with PDRAB bacteremia were related to the medical conditions of the patients at the time of development of bacteremia and could be predicted by the MODS. The only way to limit the spread is through strict preventive measures for nosocomial infection and antibiotic control.

Acinetobacter Infections↗
PubMed2003

Community-acquired bacteremic cellulitis caused by Acinetobacter baumannii.

Acinetobacter baumannii is rarely encountered as a pathogen causing community-acquired skin and soft tissue infection. A 79-year-old man had a fever for 3 days accompanied by pain and swelling over the left leg around an old scar caused by a dog bite 10 years ago. Two sets of blood cultures and a wound culture all yielded A. baumannii. The patient's condition deteriorated initially but recovered completely after 3 weeks of meropenem treatment. This case suggests that A. baumannii should be included among pathogens with the potential to cause complicated skin infection in the community.

Acinetobacter Infections↗
PubMed2003

Severe acute respiratory syndrome (SARS) - an emerging infection of the 21st century.

Severe acute respiratory syndrome (SARS) is an emerging infection caused by a novel coronavirus known as SARS-CoV. The disease has a high propensity to spread to household members and healthcare workers and may be associated with transmission and outbreaks in the community. Severe illness in immunocompromised patients, sophisticated hospital facilities and treatment procedures, particularly those that generate aerosols, and lack of adequate isolation and control measures, can amplify transmission and contribute to so-called "super-spreading" events. The presence of non-specific clinical manifestations at presentation and a lack of validated early diagnostic methods and effective management pose great difficulty for frontline physicians in the containment of this disease. The mortality of SARS is in the region of 10 to 15%; the presence of underlying disease, high initial C-reactive protein levels, and positive SARS-CoV in nasopharyngeal aspirate samples are associated with a higher risk of respiratory failure and mortality. Despite the disappearance of SARS cases worldwide, the potential evolution of SARS-CoV in animals suggests the disease may re-emerge in the future. Heightened levels of clinical suspicion, rapid case detection and isolation, and contact tracing are essential to effective management of future outbreaks. Further ongoing requirements for successful management include research on the immunopathogenesis of SARS and the development of timely and reliable diagnostic tests, effective antiviral and immunomodulatory agents, and vaccines for the disease.

Communicable Diseases, Emerging↗
PubMed2002

Increased prevalence of erythromycin resistance in streptococci: substantial upsurge in erythromycin-resistant M phenotype in Streptococcus pyogenes (1979-1998) but not in Streptococcus pneumoniae (1985-1999) in Taiwan.

A total of 394 nonduplicate isolates of Streptococcus pyogenes collected from 1979 to 1998 and 267 nonduplicate isolates of Streptococcus pneumoniae collected from October, 1998, to May, 1999, in Taiwan were evaluated. Among the 220 erythromycin-resistant (MIC, > or =1 microg/ml) S. pyogenes isolates, 35% had an M phenotype and 65% had an ML phenotype (inducible resistance [iML], 0.5%, and constitutive resistance [cML], 64.5%). Among the 243 erythromycin-resistant S. pneumoniae isolates, the majority (65.4%) had an ML phenotype (iML, 0.4%, and cML, 65%) and 34.6% had an M phenotype. A substantial upsurge in the incidence of M-phenotype erythromycin-resistant isolates was found with time for S. pyogenes (0% in 1979-1984 and 100% in 1997-1998), and an increasing incidence of M-phenotype among erythromycin-resistant S. pneumoniae was also noted (<20% before 1994 and 45.4% in 1999). All S. pyogenes and all but four S. pneumoniae isolates exhibiting a cML or iML phenotype had harbored the ermAM gene. The presence of the mefA gene was demonstrated in all isolates of S. pyogenes and the mefE gene in all but four S. pneumoniae isolates exhibiting the M phenotype. Due to the increasing susceptibility of S. pyogenes and S. pneumoniae isolates to clindamycin, susceptibility tests of these two organisms to macrolides and clindamycin should be performed simultaneously in the clinical microbiology laboratory, particularly in areas with high rates of macrolide resistance.

Anti-Bacterial Agents↗
PubMed2002

Emergence of nosocomial candidemia at a teaching hospital in Taiwan from 1981 to 2000: increased susceptibility of Candida species to fluconazole.

The incidence of nosocomial Candida fungemia increased 36-fold from 1981 (0.8/10,000 discharges) to 2000 (28.8/10,000 discharges) at the National Taiwan University Hospital, a 2000-bed teaching hospital in northern Taiwan. To understand the current status of resistance to available antifungal agents among Candida species causing invasive infections, the in vitro susceptibilities of 222 isolates (collected from July, 1999-June, 2001) were determined. Among all of the Candida species tested, 6% and 7% were resistant to fluconazole and itraconazole, respectively. The MIC90 values of voriconazole and amphotericin B were 0.5 and 1 microg/ml, respectively, although some isolates of C. krusei (amphotericin B and voriconazole MIC, >64 microg/ml) and C. tropicalis and C. glabrata (voriconazole MICs, >64 microg/ml) were less susceptible to voriconazole or amphotericin B. About one-half of the C. glabrata isolates belonged to susceptible dose-dependent (SDD, 36%) or resistant (12%) categories for fluconazole and 96% belonged to SDD (56%) or resistant (40%) category for itraconazole. When compared with fluconazole susceptibility data of blood Candida isolates recovered from patients treated at the same hospital (NTUH) from two different time periods (January, 1994, to June, 1995, and January, 1997, to June, 1999 described in previous reports), the incidence of increased susceptibility of non-krusei Candida isolates to fluconazole was evident. This trend of increasing susceptibility for fluconazole did not correlate to the increasing use of this agent in the hospital. None of the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR using four random oligonucleotide primers for 14 isolates, which exhibited fluconazole MICs of > or = 16 microg/ml, were identical, indicating an absence of clonal dissemination among these isolates in the hospital.

Antifungal Agents↗
PubMed2002

Antimicrobial susceptibilities among clinical isolates of extended-spectrum cephalosporin-resistant Gram-negative bacteria in a Taiwanese University Hospital.

Infections caused by Gram-negative bacteria with resistance to extended-spectrum cephalosporins require the identification of effective alternative antimicrobial therapy. To determine the role of other pre-existing or currently available antimicrobial agents in treating infections caused by these multidrug-resistant pathogens, we evaluated the in vitro susceptibilities of these agents in 411 non-duplicate isolates of extended-spectrum cephalosporin-resistant Gram-negative bacteria recovered between January 1999 and December 1999 in a major teaching hospital in Taipei, Taiwan. These isolates included cefotaxime-resistant (MICs > or = 2 mg/L) Escherichia coli (66 isolates) and Klebsiella pneumoniae (77 isolates); cefotaxime-resistant (MICs > or = 64 mg/L) Enterobacter cloacae (59 isolates), Serratia marcescens (52 isolates) and Citrobacter freundii (52 isolates); and ceftazidime-resistant (MICs > or = 64 mg/L) Pseudomonas aeruginosa (50 isolates) and Acinetobacter baumannii (55 isolates). Overall, carbapenems (imipenem and meropenem) had good activity against the cefotaxime-resistant Enterobacteriaceae tested (>90% of isolates were susceptible). However, carbapenems had limited activity against the ceftazidime-resistant P. aeruginosa (only 4% of isolates were susceptible) and A. baumannii (51-56% of isolates were susceptible). Among the E. coli and K. pneumoniae isolates tested, 33.3% and 58.4%, respectively, exhibited extended-spectrum beta-lactamase phenotype, determined by the double disc method. Over 80% of cefotaxime-resistant E. cloacae and C. freundii were susceptible to cefepime, but this agent had limited activity against other bacteria tested. Susceptibilities of these isolates to ciprofloxacin varied, ranging from 25% for A. baumannii to 92% for E. cloacae. Newer fluoroquinolones (moxifloxacin and trovafloxacin) had equal or less activity against these organisms, except for A. baumannii for which their MIC(90)s (8-16 mg/L) were four- to 16-fold less than that of ciprofloxacin (MIC(90) 128 mg/L).

Cefotaxime↗
PubMed2002

Endocarditis caused by Abiotrophia defectiva in children.

Abiotrophia defectiva, formerly designated as the member of nutritionally variant streptococci, is a part of normal oral flora and may be a cause of culture-negative endocarditis. We report a case of infective endocarditis caused by A. defectiva involving the mitral valve in a 12-year-old girl. She received antibiotic treatment for 8 weeks and was symptom-free 6 months after discharge. We also reviewed the pediatric cases of nutritionally variant streptococcal endocarditis published in the English literature since 1971.

Anti-Bacterial Agents↗
PubMed2002

Chromobacterium violaceum infection in children: a case of fatal septicemia with nasopharyngeal abscess and literature review.

This previously healthy 5-year-old boy initially presented with fever and purulent conjunctivitis. The course evolved rapidly into preseptal and facial cellulitis, nasopharyngeal abscess and sepsis. Chromobacterium violaceum was isolated from conjunctival exudate and blood cultures. He received intravenous cefazolin therapy for 2 days, followed by penicillin, oxacillin and netilmicin. However, no improvement was noted, and he died on the fifth days of illness.

Abscess↗
PubMed2002

High incidence of cefoxitin and clindamycin resistance among anaerobes in Taiwan.

Susceptibilities to 16 antimicrobial agents were determined by measurement of MICs for 344 isolates of anaerobic bacteria recovered from patients with significant infections. Resistance rates varied among antimicrobial agents and the species tested. The beta-lactams were more active in gram-positive than in gram-negative anaerobes. Resistance to meropenem was low (<1%). For beta-lactam-beta-lactamase inhibitors, piperacillin-tazobactam was most active for all species (resistance, <6%). The rates of resistance to cefoxitin (31 to 65%) and clindamycin (50 to 70%) for non-Bacteroides fragilis species of the B. fragilis group were higher than those for B. fragilis (4% resistant to cefoxitin and 33% resistant to clindamycin). Among members of B. fragilis group, Bacteroides thetaiotaomicron was the most resistant to clindamycin (70%) and cefoxitin (65%). Rates of susceptibility to imipenem and metronidazole for B. fragilis continue to be high compared to those from a previous study 10 years ago. However, resistance to metronidazole was found recently in five strains of B. fragilis. We analyzed the genetic relationships among the metronidazole-resistant B. fragilis strains by pulsed-field gel electrophoresis. The metronidazole-resistant B. fragilis strains showed genotypic heterogeneity, excluding the dissemination of a single clone.

Anti-Bacterial Agents↗
PubMed2002

Induction of cytokines by glucosyltransferases of streptococcus mutans.

Production of proinflammatory cytokines is implicated in the pathogenesis of viridans streptococcus-induced alpha-streptococcal shock syndrome and infective endocarditis. Streptococcus mutans, one of the opportunistic pathogens causing infective endocarditis, was reported previously to stimulate monocytes and epithelial and endothelial cells in vitro to produce various cytokines. We found that glucosyltransferases (GTFs) GtfC and GtfD of S. mutans stimulated predominantly the production of interleukin-6 (IL-6) from T cells cultured in vitro. The level of IL-6 but not of tumor necrosis factor alpha in blood was significantly elevated when rats were injected intravenously with S. mutans GS-5, whereas IL-6 was detected at a much lower level when rats were challenged with NHS1DD, an isogenic mutant defective in the expression of GTFs. The serum IL-6 level was elevated in patients with endocarditis caused by different species of viridans streptococci which express GTF homologues. Affinity column-purified GTFs reduced the levels of detectable IL-2 of T cells stimulated by another bacterial antigen, tetanus toxoid. These results suggested that GTFs might modulate the production of Th1-type cytokines and that GTFs of S. mutans play a significant role in stimulating the production of the proinflammatory cytokine IL-6 in vivo.

Adult↗
PubMed2002

groESL sequence determination, phylogenetic analysis, and species differentiation for viridans group streptococci.

The full-length sequences of the groESL genes (also known as cpn10/60) of Streptococcus anginosus, Streptococcus constellatus, Streptococcus gordonii, and Streptococcus sanguis and the near full-length sequence of the groESL genes of Streptococcus intermedius, Streptococcus bovis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus salivarius were determined. The lengths of the groES genes from the 10 species listed above ranged from 282 to 288 bp, and the full-length sequences of groEL determined for 4 species (S. anginosus, S. constellatus, S. gordonii, and S. sanguis) revealed that each was 1,623 bp. The intergenic region (spacer) between the groES and groEL genes varies in size (15 to 111 bp) and sequence between species. The variation of the groES sequences among the species tested was greater (62.1 to 95.1% nucleotide sequence identities) than that of the groEL sequences (77.2 to 95.2% nucleotide sequence identities). Phylogenetic analysis of the groES and groEL genes yielded evolutionary trees similar to the tree constructed by use of the 16S rRNA gene. The intraspecies variation of the spacer was minimal for clinical isolates of some species. The groESL sequence data provide an additional parameter for identification of viridans group streptococcal species.

Bacterial Proteins↗
PubMed2002

Current status of antimicrobial resistance in Taiwan.

While some trends in antimicrobial resistance rates are universal, others appear to be unique for specific regions. In Taiwan, the strikingly high prevalence of resistance to macrolides and streptogramin in clinical isolates of gram-positive bacteria correlates with the widespread use of these agents in the medical and farming communities, respectively. The relatively low rate of enterococci that are resistant to glycopeptide does not parallel the high use of glycopeptides and extended-spectrum beta-lactams in hospitals. The evolving problem of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates is substantial, and some unique enzymes have been found. Recently, some gram-negative bacteria (e.g., Pseudomonas aeruginosa and Acinetobacter baumannii) that are resistant to all available antimicrobial agents including carbapenems have emerged.

Bacterial Infections↗
PubMed2002

Pandrug-resistant Acinetobacter baumannii causing nosocomial infections in a university hospital, Taiwan.

The rapid emergence (from 0% before 1998 to 6.5% in 2000) of pandrug-resistant Acinetobacter baumannii (PDRAB) was noted in a university hospital in Taiwan. To understand the epidemiology of these isolates, we studied 203 PDRAB isolates, taken from January 1999 to April 2000: 199 from 73 hospitalized patients treated at different clinical settings in the hospital and 4 from environmental sites in an intensive-care unit. Pulsed-field gel electrophoresis analysis and random amplified polymorphic DNA (RAPD) generated by arbitrarily primed polymerase chain reaction of these 203 isolates showed 10 closely related genotypes (10 clones). One (clone 5), belonging to pulsotype E and RAPD pattern 5, predominated (64 isolates, mostly from patients in intensive care). Increasing use of carbapenems and ciprofloxacin (selective pressure) as well as clonal dissemination might have contributed to the wide spread of PDRAB in this hospital.

Acinetobacter↗