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Biomedical subjects

Po-Ren Hsueh

Publications and source records attributed to Po-Ren Hsueh.

At least 73 records · Page 4Linked to original sources

Development of immunoglobulin G enzyme-linked immunosorbent assay for the serodiagnosis of severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is an emerging infectious disease caused by a novel SARS-associated coronavirus (SARS-CoV). The clinical characteristics are high fever, rapidly progressive diffuse pneumonitis and respiratory distress. It is highly infectious through intimate contact or direct contact with infectious body fluids. Outbreaks within communities and hospitals have been reported. Development of rapid and reliable diagnostic tools is urgently needed. We developed an immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA), using whole virus antigen of SARS-CoV. Eighty-six serum samples collected from patients who were hospitalized for other causes were examined to determine the cut-off O.D. value. The cut-off O.D. value was defined as 0.175 by calculating the mean O.D. value of the 86 sera plus 3 standard deviations. To determine the sensitivity and specificity of the ELISA, 56 positive sera and 204 negative sera were tested. The sensitivity was 96.4% and the specificity was 100%. The results suggest that the IgG ELISA using whole virus antigen of SARS-CoV has a high sensitivity and specificity in detecting SARS IgG antibodies. This IgG ELISA is a powerful tool for serodiagnosis of SARS.

Antigens, Viral↗

Recurrent infections caused by cefotaxime- and ciprofloxacin-resistant Salmonella enterica serotype choleraesuis treated successfully with imipenem.

We present a case of recurrent infection (infective spondilitis, psoas abscess, and bacteraemia) caused by a single strain of cefotaxime- and ciprofloxacin-resistant and bla(CMY-2)-containing Salmonella enterica serotype choleraesuis during a 4-month period in a patient with uremia. The patient was successfully treated with imipenem for 7 weeks. Our observation indicates that a carbapenem might be considered as a drug of choice for the treatment of infections caused by this emerging multi-resistant pathogen.

Anti-Bacterial Agents↗

Acremonium pyomyositis in a pediatric patient with acute leukemia.

Invasive Acremonium infection in humans is rare. We report a patient with leukemia who developed pyomyositis due to Acremonium species. Painful cutaneous nodules and severe myalgia were the first clinical manifestations during the neutropenic stage after chemotherapy. Magnetic resonance image (MRI) revealed multiple nodular lesions scattered along the intramuscular regions of the lower legs. Culture of an aspiration grew Acremonium species. Surgical drainage was performed. Although all antifungal agents tested showed no in vitro inhibitory activity, we successfully treated this patient with amphotericin B, granulocyte colony-stimulating factor (G-CSF), and surgical drainage.

Acremonium↗

Antimicrobial drug resistance in salmonella-infected aortic aneurysms.

BACKGROUND: Salmonella infection of the aorta and adjacent arteries is rare, but life-threatening. There is an increasing number of infections caused by antimicrobial drug resistant Salmonella. This study sought to assess the association between antimicrobial drug resistance and clinical outcomes of patients with Salmonella-infected aortic aneurysm. METHODS: Data were collected by retrospective chart review. Between October 1995 and October 2004, 34 patients with Salmonella-infected aortic aneurysm were included. Aneurysm-related deaths were defined as hospital deaths and late deaths due to prosthetic graft infection. Analysis was performed using the chi2 test, Fisher's exact test, and Mann-Whitney test. RESULTS: Nineteen patients had a suprarenal and 15 patients had an infrarenal aortic infection. The most common responsible pathogen was group C Salmonella (47%). Ciprofloxacin-resistant Salmonella infection occurred since March 2001 and the rate increased from 0 per 15 in the years before March 2001 to 5 per 19 in the years after March 2001 (p = 0.005 by Fisher's exact test). Among the 26 patients who had combined medical and surgical therapy, 4 died in the hospital and 4 died of late prosthetic graft infection 3 to 6 months after operation, whereas 4 of the 8 who had medical therapy alone died of aneurysm rupture during hospitalization. The actuarial survival rates by the Kaplan-Meier method were 64% at 6 months, 61% at 1 year, and 56% at 5 years. The risk factors for aneurysm-related death were old age (78.5 +/- 9.7 years vs 63.5 +/- 11.4 years; p < 0.001) and ciprofloxacin-resistant Salmonella infection (4 of 5 vs 8 of 29; p = 0.042). CONCLUSIONS: There was an increased mortality associated with ciprofloxacin resistance in infected aortic aneurysms with Salmonella. With an increasing incidence of ciprofloxacin resistant Salmonella, third generation cephalosporin is the antibiotic of choice for Salmonella-infected aneurysm.

Adult↗

Nosocomial infections due to methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococci at a university hospital in Taiwan from 1991 to 2003: resistance trends, antibiotic usage and in vitro activities of newer antimicrobial agents.

A rapid increase of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection (from 39% in 1991 to 75% in 2003) and vancomycin-resistant enterococci (VRE) (from 1.2% in 1996 to 6.1% in 2003) at a university hospital in Taiwan was found. The noticeable rise of MRSA and VRE was significantly correlated with the increased consumption of glycopeptides, beta-lactam-beta-lactamase inhibitor combinations, extended-spectrum cephalosporins, carbapenems and fluoroquinolones (Pearson's correlation coefficient, P < 0.05). Minimum inhibitory concentrations (MICs) of 100 non-duplicate blood isolates of MRSA (in 2003) and of 25 non-duplicate isolates of vancomycin-resistant Enterococcus faecalis and 172 vancomycin-resistant Enterococcus faecium (in 1996-2003) causing nosocomial infection recovered from various clinical specimens of patients treated at the hospital to nine antimicrobial agents were determined by the agar dilution method. All of these isolates were susceptible to linezolid and were inhibited by 0.5mg/L of tigecycline, and all MRSA isolates were inhibited by daptomycin 1mg/L, including two isolates of MRSA with heteroresistance to vancomycin. Daptomycin had two-fold better activity against vancomycin-resistant E. faecalis (MIC90, 2 mg/L) than against vancomycin-resistant E. faecium (MIC90, 4 mg/L). Decreased susceptibilities of vancomycin-resistant E. faecium and MRSA to quinupristin/dalfopristin (non-susceptibility 25% and 8%, respectively) were found. Telithromycin had poor activity against the isolates tested (MIC90, 8 mg/L). Linezolid, daptomycin and tigecycline may represent therapeutic options for infections caused by these resistant Gram-positive organisms.

Anti-Bacterial Agents↗

Endocarditis caused by Propionibacterium acnes: an easily ignored pathogen.

Propionibacterium acnes, which usually considered as a contaminant, has been found to be an emerging pathogen in human diseases. We describe a case of prosthetic valve related endocarditis caused by P. acnes. Sequencing of the genetic coding of 16S ribosomal RNA was used to identify the pathogen and random amplified polymorphic DNA patterns further confirmed the persistent bacteraemia, which help to determine the diagnosis.

Anti-Bacterial Agents↗

Renal hypouricemia is an ominous sign in patients with severe acute respiratory syndrome.

BACKGROUND: The purpose of this study is to determine the incidence and significance of hypouricemia in patients with severe acute respiratory syndrome (SARS). Pulmonary lesions in patients with SARS are thought to result from proinflammatory cytokine dysregulation. Acute renal failure has been reported in patients with SARS, but whether cytokines can injure renal tubules is unknown. METHODS: Sixty patients diagnosed with SARS in Taiwan in April 2003 were studied. Patients were identified as hypouricemic when their serum uric acid (UA) level was less than 2.5 mg/dL (<149 micromol/L) within 15 days after fever onset. Urine UA and creatinine levels were available for 43 patients; the serum cytokines interleukin-6 (IL-6), IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured in 16 patients. RESULTS: Sixteen patients (26.7%) had hypouricemia (UA, 1.68 +/- 0.52 mg/dL [100 +/- 31 micromol/L]). No differences in age, sex, symptoms, vital signs, hemogram, or other biochemistry data existed between the hypouricemic and normouricemic groups. Fractional excretion (FE) of UA (FE UA) in 12 hypouricemic patients was 39.6% +/- 23.4%, significantly greater than that of 31 normouricemic patients (16.4% +/- 11.4%; P < 0.0001). After adjustments for age and sex, high FE UA was significantly associated with the lowest blood oxygenation (P = 0.001; r = -0.624). The number of catastrophic outcomes (endotracheal intubation and/or death) adjusted for older age and sex showed that hypouremic patients had an odds ratio of 10.57 (confidence interval, 2.33 to 47.98; P = 0.002). Kaplan-Meier curves for catastrophic outcome-free results showed significant differences between patients with normouricemia or hypouricemia (P = 0.01). Serum IL-8 levels correlated significantly with FE UA (P < 0.001; r = 0.785) and inversely with serum UA level (P = 0.044; r = -0.509); neither IL-6 nor TNF-alpha level showed such correlations. CONCLUSION: One fourth of patients with SARS developed hypouricemia, which might result from a defect in renal UA handling and was associated with a high serum IL-8 level. Renal hypouricemia is an ominous sign in patients with SARS.

Carrier Proteins↗

CAPD-related peritonitis due to Salmonella enteritidis in a patient with SLE.

Patients with systemic lupus erythematosus are prone to various infections, often associated with high mortality. Salmonella species are a rare cause of continuous ambulatory peritoneal dialysis (CAPD) peritonitis, but patients with lupus are susceptible to infection caused by Salmonella species. A 47-year-old woman who had systemic lupus erythematosus with end-stage renal disease and was undergoing CAPD presented with fever, watery diarrhea, abdominal pain, and turbid dialysate effluent. The effluent culture yielded Salmonella enteritidis. Although she was administered antibiotics to which the organism was susceptible in vitro, peritonitis was not cured. Her clinical condition stabilized after removal of the Tenckhoff catheter and prolonged antibiotic use. In Salmonella-related CAPD peritonitis, early catheter removal may be necessary to achieve complete treatment.

Catheterization↗

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↗

Disseminated Nocardia farcinica infection in a uraemia patient with idiopathic thrombocytopenia purpura receiving steroid therapy.

Nocardia farcinica has been reported as an increasingly frequent cause of localized and disseminated infections in immunocompromised patients in recent years, but N. farcinica bacteraemia remains a rare finding. Here, the case is described of a 68-year-old man with end-stage renal disease and idiopathic thrombocytopenia purpura treated with steroid therapy who developed disseminated infection (bacteraemia, multilobar pneumonia and brain abscesses) due to N. farcinica. The isolate was confirmed by partial sequencing analysis of the 16S rRNA gene. The patient recovered after prolonged trimethoprim-sulfamethoxazole therapy with no recurrence in over 1 year.

Aged↗

Species identification of mutans streptococci by groESL gene sequence.

The near full-length sequences of the groESL genes were determined and analysed among eight reference strains (serotypes a to h) representing five species of mutans group streptococci. The groES sequences from these reference strains revealed that there are two lengths (285 and 288 bp) in the five species. The intergenic spacer between groES and groEL appears to be a unique marker for species, with a variable size (ranging from 111 to 310 bp) and sequence. Phylogenetic analysis of groES and groEL separated the eight serotypes into two major clusters. Strains of serotypes b, c, e and f were highly related and had groES gene sequences of the same length, 288 bp, while strains of serotypes a, d, g and h were also closely related and their groES gene sequence lengths were 285 bp. The groESL sequences in clinical isolates of three serotypes of S. mutans were analysed for intraspecies polymorphism. The results showed that the groESL sequences could provide information for differentiation among species, but were unable to distinguish serotypes of the same species. Based on the determined sequences, a PCR assay was developed that could differentiate members of the mutans streptococci by amplicon size and provide an alternative way for distinguishing mutans streptococci from other viridans streptococci.

Bacterial Proteins↗

The erm(T) gene is flanked by IS1216V in inducible erythromycin-resistant Streptococcus gallolyticus subsp. pasteurianus.

We investigated the sequence and the genetic context of the erm(T) gene in six inducible erythromycin-resistant Streptococcus gallolyticus subsp. pasteurianus (formerly S. bovis biotype II.2) isolates. In all isolates, the erm(T) genes were flanked by two IS1216V-like elements with the same polarity and were found to be inserted in the chromosome.

Amino Acid Sequence↗

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↗

Identification of clinically relevant enterococcus species by direct sequencing of groES and spacer region.

We determined the groESL sequences (groES, groEL, and the intergenic spacer) of 10 clinically relevant Enterococcus species and evaluated the feasibility of identifying Enterococcus species on the basis of these sequences. Seven common clinical Enterococcus species, E. faecalis, E. faecium, E. casseliflavus, E. gallinarum, E. avium, E. raffinosus, and E. hirae, and three less common Enterococcus species, E. cecorum, E. durans, and E. mundtii, were examined in this study. We found that the groES genes of these enterococcal species are identical in length (285 nucleotides) and contain an unusual putative start codon, GTG. The lengths and sequences of the intergenic regions (spacers between the groES and groEL genes) are quite variable (17 to 57 bp in length) among Enterococcus species but are conserved in strains within each species, with only a few exceptions. Considerable variation of groES or groEL sequences was also observed. The evolutionary trees of groES or groEL sequences revealed similarities among Enterococcus species. However, the overall intraspecies variation of groES was less than that of groEL. The high interspecies variation and low intraspecies variation indicate that the groES and spacer sequences are more useful than groEL for identification of clinically relevant Enterococcus species. The sequences of these two genetic traits, groES and spacer, can be determined by a single PCR and direct sequencing and may provide important information for the differentiation of closely related species of Enterococcus.

Bacterial Typing Techniques↗