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Biomedical subjects

Yao-Shen Chen

Publications and source records attributed to Yao-Shen Chen.

At least 19 recordsLinked to original sources
PubMed2006

Presence of the exoU gene of Pseudomonas aeruginosa is correlated with cytotoxicity in MDCK cells but not with colonization in BALB/c mice.

A total of 141 independent strains of Pseudomonas aeruginosa with different heterogeneities in the exo gene (exoS, exoT, exoU, and exoY) background were examined for their pathogenic roles. Results indicated that the exoU gene is the major contributor to cytotoxicity in Madin-Darby canine kidney cells but is not related to bacterial colonization in mice.

Animals↗
PubMed2006

Study on the association between estrogen receptor gene (ESR) and reproduction traits in Landrace pigs.

To study the potential use of estrogen receptor gene (ESR) as a genetic marker to improve the reproductive traits of pigs, the genotypes of the ESR PCR product digested by Pvu II were determined in 2,239 litters from 612 Landrace sows. The data of the first, second, and later parities were separately evaluated. Although the frequency of the B allele was much lower than that of the A allele, likelihood ratio test showed that the gene frequencies were in Hardy-Weinberg equilibrium. The effects of ESR of different parities were not equal. In summary, the sows with the BB genotype showed better performance for total number of piglets born (TNB) and number of piglets born alive (NBA), but had a lower average piglet weight at birth (AWB). It was concluded that ESR could be used as a marker for the selection of litter size in the Landrace population.

Animals↗
PubMed2006

Pyogenic liver abscess caused by Burkholderia pseudomallei in Taiwan.

Pyogenic liver abscess in Taiwan is a well-known disease entity, commonly associated with a single pathogen, Klebsiella pneumoniae. Melioidosis is an endemic disease in Taiwan that can manifest as multiple abscesses in sites including the liver. We report three cases of liver abscesses caused by Burkholderia pseudomallei. The first patient was a 54-year-old diabetic woman, who presented with liver abscess and a left subphrenic abscess resulting from a ruptured splenic abscess, co-infected with K. pneumoniae and B. pseudomallei. The second patient, a 58-year-old diabetic man, developed bacteremic pneumonia over the left lower lung due to B. pseudomallei with acute respiratory distress syndrome, and relapsed 5 months later with bacteremic abscesses of the liver, spleen, prostate and osteomyelitis, due to lack of compliance with prescribed antibiotic therapy. The third patient was a 61-year-old diabetic man with a history of travel to Thailand, who presented with jaundice and fever of unknown origin. Liver and splenic abscesses due to B. pseudomallei were diagnosed. A high clinical alertness to patients' travel history, underlying diseases, and the presence of concomitant splenic abscess is essential to early detection of the great mimicker, melioidosis. The treatment of choice is intravenous ceftazidime for at least 14 days or more. An adequate duration of maintenance oral therapy, with amoxicillin-clavulanate or trimethoprim-sulfamethoxazole for 12-20 weeks, is necessary to prevent relapse. Liver abscess in Taiwan is most commonly due to K. pneumoniae, but clinicians should keep in mind that this may be a presenting feature of melioidosis.

Anti-Bacterial Agents↗
PubMed2006

Invasive pulmonary aspergillosis with cerebral abscess in a patient with idiopathic thrombocytopenic purpura.

Invasive aspergillosis is a devastating infection in immunocompromised hosts. The lung is the most common site of primary infection, and the central nervous system is the most common secondary site of invasive disease. Invasive aspergillosis in autoimmunopathies treated with corticosteroids has rarely been reported in the literature. Herein, we report the case of a 48-year-old female patient with idiopathic thrombocytopenic purpura complicated with fatal invasive pulmonary and cerebral aspergillosis. She had been given 1,016 g intravenous amphotericin B empirically for lung infection during a previous admission. At presentation, she had fever, cough, and shortness of breath for 4 weeks. Chest radiography revealed a huge cavity over the left upper lung field. Bronchoscopic biopsy and culture showed Aspergillus species. She was initially treated with intravenous amphotericin B (0.9 mg/kg/day), and intravenous hydrocortisone for her idiopathic thrombocytopenic purpura. However, deterioration of consciousness occurred 12 days after hospitalization. Computed tomography of the brain showed ring-like cystic mass lesions in the right side basal ganglion. Stereotactic aspiration of the brain revealed Aspergillus species. Her condition exacerbated despite combination treatment with high-dose amphotericin B (1.2 mg/kg/day) and itraconazole (400 mg/day). She died 24 days after admission. This case suggests that treatment with corticosteroids and premature discontinuation of antifungal drugs bear the risk of fatal cerebral involvement in patients with invasive pulmonary aspergillosis.

Amphotericin B↗
PubMed2006

CpG-modified plasmid DNA encoding flagellin improves immunogenicity and provides protection against Burkholderia pseudomallei infection in BALB/c mice.

The plasmid DNA encoding the fliC gene of Burkholderia pseudomallei combined with CpG oligodeoxynucleotide (ODN) was injected intramuscularly into BALB/c mice, resulting in the increased production of certain humoral antibodies and flagellin-specific spleen cell clonal expansion. CpG ODN, as an immunoadjuvant, was added to the plasmid containing the fliC gene in order to obtain ongoing expression in muscle for a long period. Functional expression of flagellin from the constructed CpG-modified plasmid in transfected peritoneal exudate cells of BALB/c mice was shown by reverse transcription-PCR and Western blotting. Furthermore, BALB/c mice immunized with the modified plasmid had relatively higher resistance to B. pseudomallei infection in vivo than did mice immunized with unmodified plasmid DNA. The time course of restricted bacterial growth in spleen and liver and changes in the cytokine profiles of immunized mice suggested that the stimulated phagocytic cells would be able to kill the bacteria eventually, possibly as a consequence of the induction of Th-1-type immune polarization in vivo. Th-1-type immune polarization was detected in response to flagellin induction in mice immunized with CpG-modified plasmid DNA by the appearance of increased levels of immunoglobulin G2a antibodies and gamma interferon-secreting cells specific to flagellin. The exogenous CpG motifs added to the fliC gene would contribute to an adjuvant-like response that enhances the flagellin-specific immunogenicity and provides protection against B. pseudomallei infection. This CpG-modified plasmid DNA vaccination is an important potential strategy that should be developed to protect against melioidosis.

Adjuvants, Immunologic↗
PubMed2006

Opportunistic infections in adults with acquired immunodeficiency syndrome: a comparison of clinical and autopsy findings.

BACKGROUND AND PURPOSE: Many opportunistic infections causing death in acquired immunodeficiency syndrome (AIDS) patients are often not diagnosed prior to death. The objective of this study was to compare the premortem and postmortem diagnoses of opportunistic infections and tumors among 15 AIDS patients treated in a hospital in southern Taiwan. METHODS: Total autopsy (brain, chest and abdominal cavity) was performed in 2 patients, and partial autopsy in 13. RESULTS: Pneumocystis carinii pneumonia, candidiasis, lymphoma, Kaposi's sarcoma, toxoplasmosis and salmonellosis were more commonly diagnosed before death than at autopsy. By contrast, cytomegalovirus (CMV) infections and herpes simplex virus or varicella-zoster virus infections were more frequently diagnosed at postmortem examinations than prior to death. CONCLUSIONS: In conclusion, this study found substantial discrepancies between autopsy findings and premortem clinical diagnoses in AIDS patients, especially for CMV infection.

AIDS-Related Opportunistic Infections↗
PubMed2006

Mycobacterium marinum tenosynovitis: three case reports and review of the literature.

Mycobacterium marinum is one of the nontuberculosis mycobacteria responsible for skin infections. There have been very few case series of M. marinum infections reported in the English literature. Herein, we describe three patients with M. marinum tenosynovitis. All patients had positive cultures and were exposed to pricking by a fishbone. The incubation period ranged from 7 to 60 days. Key elements in the diagnosis of this infection were a high index of suspicion raised by negative bacterial tissue cultures, poor response to conventional antibiotics treatment, a history of exposure to tropical fish and tissue biopsy for culture and histology. The treatment is essentially antimicrobial therapy supplemented by an appropriate surgical debridement, especially when deep structures are involved.

Anti-Bacterial Agents↗
PubMed2005

Trends in fluoroquinolone resistance of Mycobacterium tuberculosis complex in a Taiwanese medical centre: 1995-2003.

OBJECTIVES: Fluoroquinolones are being used more frequently for the treatment of multidrug-resistant (MDR) strains of Mycobacterium tuberculosis complex (MTB). This study was designed to determine the frequency of the emergence of fluoroquinolone-resistant strains in Taiwan and to assess whether this might be due to use of fluoroquinolones for treatment of patients with MDR or because of increased use of fluoroquinolones in the community for treatment of other infections. We also sought to determine whether there might be clonal spread of fluoroquinolone resistance. METHODS: A total of 3497 clinical isolates of M. tuberculosis complex were obtained during 1995-2003, of which 141 were selected. They consisted of 62 isolates fully susceptible to four first-line drugs, 33 isolates resistant to rifampicin and isoniazid (MDR), and 46 isolates with a variety of any drug resistant patterns other than MDR (combination group). The MICs were determined for ciprofloxacin, ofloxacin and levofloxacin. RESULTS: An increase in the MIC90 and rates of resistance to ciprofloxacin, ofloxacin and levofloxacin were noted only in the MDR group. The rates were higher among strains isolated between 1998-2003 compared with those obtained between 1995-1997 (rate of resistance, 20% versus 7.7%; MIC > or = 4 mg/L versus 1-2 mg/L). Among the 10 fluoroquinolone-resistant isolates, five (50%) possessed mutations other than S95T in the gyrA gene. No gyrB mutation was found in any of the clinical isolates. CONCLUSIONS: These findings suggest that fluoroquinolone resistance is the result of treatment of patients with MDR strains rather than from use in the general community in Taiwan. The emergence of fluoroquinolone resistance among MDR strains reinforces the need for routine fluoroquinolone susceptibility testing whenever these drugs might be used.

Amino Acid Substitution↗
PubMed2005

Immunogenicity and anti-Burkholderia pseudomallei activity in Balb/c mice immunized with plasmid DNA encoding flagellin.

Plasmid DNA encoding the flagella protein (flagellin) was used as a vaccination candidate for the evaluation of its immunogenicity and for protection against infection with Burkholderia pseudomallei. Firstly, flagellin encoding plasmid DNA was injected into Balb/c mice intramuscularly and this elicited both a humoral and a cellular immune response. Total IgG production and the clonal expansion of the spleen cells increased in response to flagellin. The IgG subclass response exhibited a dominance of IgG2a over IgG1 in the sera. In addition, IFN-gamma-secreting cells in the spleen were substantially increased. Furthermore, the anti-B. pseudomallei activity of the peritoneal exudate cells was evaluated by a Transwell tissue-culture plate system where the macrophage-activating related cytokines in upper chamber were allowed to cross the plate's membrane and stimulate the activation of peritoneal exudate cells in lower chamber. Our results indicated that the activated peritoneal exudate cells were able to restrict the growth of B. pseudomallei in vitro. Indeed, subsequent intravenous challenge of the vaccinated Balb/c mice with 10(5)CFU of B. pseudomallei resulted in the number of bacterial cells detected in liver and/or spleen being significantly reduced in the flagellin plasmid DNA vaccinated mice. At 7 days subsequent to infection of B. pseudomallei, 5/6 (83%) of flagellin plasmid DNA vaccinated mice had survived. We suggest that plasmid DNA-encoding flagellin might be useful as a potential immunization route for the future development of a vaccine against melioidosis in related animals.

Animals↗
PubMed2005

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

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

Acquired Immunodeficiency Syndrome↗
PubMed2005

Clinical manifestations of Kikuchi's disease in southern Taiwan.

Histiocytic necrotizing lymphadenitis, or Kikuchi's disease (KD), is a self-limiting cervical lymphadenitis of unknown origin. The diagnosis of KD is problematic due to the lack of specific laboratory tests. This study reviewed the clinical characteristics of 58 patients with KD. Clinical manifestations were of considerable diversity. The mean age of patients was 24.88 +/- 7.44 years and there was a female predominance (1.76:1). The most frequent clinical findings were enlarged tender lymph nodes (50%), fever (43%), sore throat (21%), non-productive cough (12%), headache (10%), chills (9%) and rhinorrhea (9%). The most common initial laboratory abnormalities were leukopenia (29%), elevated erythrocyte sedimentation rate (14%), liver function impairment (14%), elevated C-reactive protein level (12%), and anemia (10%). Most patients had unilateral lymph node involvement (79%), which was usually located in the posterior triangle of the cervical lymph nodes (90%). Most patients had no comorbid disease (93%). No recurrence occurred. KD should be included in the differential diagnosis of fever with cervical lymphadenopathy.

Adolescent↗
PubMed2005

Seroprevalence of melioidosis in diabetic patients in Taiwan.

Diabetes mellitus is a major predisposing factor for Burkholderia pseudomallei infection. This study surveyed serum samples from 356 Taiwanese patients with diabetes mellitus for anti-flagellin antibodies against B. pseudomallei. Antibody titer to B. pseudomallei was positive in 3.0% (11/365) of diabetes mellitus patients. All seropositive individuals were aged > or =60, indicating that elderly and diabetic adults are at high risk of B. pseudomallei infection. In this study, diabetic females, who were usually housewives, had a seropositive rate of 81.1%. However, the incidence of melioidosis in males (usually working outdoors) was 93.7% based on clinical cases. We suggest that exposure of males and females to B. pseudomallei in this study was via different routes of infection.

Adult↗
PubMed2005

Preservation of clinical isolates of Mycobacterium tuberculosis complex directly from MGIT culture tubes.

Preservation of M. tuberculosis complex strains isolated from clinical specimens is important for epidemiological investigations related to tuberculosis. In this study the efficacy of preservation was evaluated by calculating the recovery rate of preserved strains, with various patterns of resistance, after periods of storage and subculture. The recovery rates from strains preserved in enriched solid medium were >90% for storage periods <or=6 yr. However, this procedure for storing mycobacteria is time-consuming, labor-intensive, and impractical for routine use in a clinical laboratory setting. This study shows that recovery rates for strains preserved directly from MGIT fluids are satisfactory for storage periods <or=2 yr. No significant difference in viability was observed within 3 categories of drug resistance: (i) all-susceptible, (ii) multi-drug resistant (MDR), and (iii) a combination of other patterns of resistance. Preserving clinical M. tuberculosis strains directly from MGIT culture fluid fits easily into laboratory routine and is feasible for use in a clinical laboratory setting.

Culture Media↗
PubMed2005

A prospective etiologic study of community-acquired pneumonia in Taiwan.

BACKGROUND AND PURPOSE: The treatment of community-acquired pneumonia (CAP) is complicated by the growing threat of antimicrobial resistance and the tendency to rely on empirical therapy. This study investigated the etiologic agents of adult CAP in Taiwan and the susceptibility of Streptococcus pneumoniae isolates from these patients. METHODS: A collaborative group was established in the emergency department to conduct a prospective study of the etiology of adult CAP. The etiologic agent was determined by a combination of microscopic, culture, serologic and antigen detection methods. Pneumococcal susceptibility testing was performed to determine the extent of penicillin resistance. RESULTS: A total of 100 consecutive cases of mild to moderate adult CAP prior to the severe acute respiratory syndrome epidemic were enrolled. The etiologic agent was determined in 72% of cases. The 5 most common causative pathogens were S. pneumoniae (26%), Mycoplasma pneumoniae (20%), Chlamydia pneumoniae (13%), Haemophilus influenzae (9%), and Klebsiella pneumoniae (5%). Atypical pathogens accounted for 40% of CAP. Bacteremic pneumonia was diagnosed in 6.2% of cases. Co-infections with 2 or more pathogens were found in 16% of the cases. Among the 20 isolates of S. pneumoniae, 85% (17/20) were susceptible to penicillin, 3 (15%) were intermediate, and none were resistant to penicillin. CONCLUSION: S. pneumoniae, M. pneumoniae and C. pneumoniae were the 3 leading causes of mild to moderate CAP in Taiwan. This study indicates that penicillin-resistant S. pneumoniae play a very limited role in this condition in adults.

Adolescent↗
PubMed2005

Colon perforation with peritonitis in an acquired immunodeficiency syndrome patient due to cytomegalovirus and amoebic colitis.

Invasive amoebiasis is rarely seen in human immunodeficiency virus (HIV)-infected individuals, even in endemic areas. By contrast, cytomegalovirus (CMV) disease is recognized as a major clinical problem in acquired immunodeficiency syndrome patients. A 34-year-old HIV-infected man with amoeba colitis, disseminated Mycobacterium avian complex and CMV infection with cecum perforation, presented with the initial symptoms of fever, shortness of breath and painful sensation when swallowing. He was treated with fluconazole, trimethoprim-sulfamethoxazole and hydrocortisone under the impression of esophageal candidiasis and Pneumocystis jiroveci pneumonia. However, diarrhea and abdominal pain developed on day 6 of hospitalization. Invasive amoebiasis and CMV colitis was diagnosed after examination of colon pathological specimens. Emergent laparotomy was performed. Right hemicolectomy with double barrel ileostomy and colostomy was done due to perforation of the cecum. Iodoquinol was given, followed by metronidazole 14 days afterwards. He underwent closure of double barrel ileostomy and colostomy 5 months later. This case illustrates the diagnostic challenge of caring for acquired immunodeficiency syndrome persons with multiple illnesses and medication use. CMV infection, amoebic colitis and possibly corticosteroid may have played a role in colon perforation in our patient.

Acquired Immunodeficiency Syndrome↗
PubMed2005

Streptococcus suis meningitis with ventriculoperitoneal shunt infection and spondylodiscitis.

Streptococcus suis is a zoonotic pathogen which causes meningitis, bacteremia, and endocarditis in pigs. Human infection is rare and often presents as meningitis with the sequela of permanent deafness and endocarditis. Previous cases were reported from pig-rearing countries such as Holland and Hong Kong. We report a 55-year-old bedridden man with S. suis meningitis complicated with ventriculoperitoneal shunt infection and lumbar spine spondylodiscitis. He presented with fever, delirium, neck stiffness, lower leg weakness and sudden onset hearing loss for several days. He was successfully treated with intravenous antibiotics, ventriculoperitoneal shunt replacement, lumbar spinal laminotomy and discectomy. Cerebrospinal fluid culture initially misidentified the organism as Streptococcus acidominimus, and S. suis was later identified by 16S rRNA sequencing. Misidentification of the microbiological findings may lead to a failure to correctly diagnose this disease. S. suis meningitis should be included in the differential diagnosis of patients with meningitis and sudden hearing loss.

Anti-Bacterial Agents↗
PubMed2004

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

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

Antitubercular Agents↗