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Background: The emergence of imipenem-resistant Pseudomonas aeruginosa (IRPA) has become a great concern worldwide. The aim of this study was to investigate resistance mechanisms associated with bloodstream isolated IRPA strains in Taiwan. Results: A total of 78 non-duplicated IRPA isolates were isolated from patients with bloodstream infection. The average prevalence of imipenem-resistance in those isolates was 5.9 % during a 10-year longitudinal surveillance in Taiwan. PFGE results showed high clonal diversity among the 78 isolates. VIM-2, VIM-3, OXA-10, and OXA-17 β-lactamases were identified in 2 (2.6 %), 3 (3.8 %), 2 (2.6 %), and 1 (1.3 %) isolates, respectively. Active efflux pumps, AmpC β-lactamase overproduction, and extended-spectrum AmpC cephalosporinases (ESACs) were found in 58 (74.4 %), 25 (32.1 %) and 15 (19.2 %) of IRPA isolates, respectively. oprD mutations with amino acid substitution, shortened putative loop L7, premature stop codon caused by point mutation, frameshift by nucleotide insertion or deletion, and interruption by insertion sequence were found in 19 (24.4 %), 18 (23.1 %), 15 (19.2 %), 14 (17.9 %), and 10 (12.8 %) of isolates, respectively. Conclusions: This study suggests that alterations in the OprD protein and having an active efflux pump are the main mechanisms associated with bloodstream isolated IRPA. Overproduction of AmpC, ESACs, and the presence of VIM- and OXA-type β-lactamases play additional roles in reduced susceptibility to imipenem in P. aeruginosa isolates in Taiwan. [ABSTRACT FROM AUTHOR]

Primary cardiac sarcomas are very rare. Infiltrative cardiac tumors may be difficult to diagnose by transthoracic echocardiography (TTE) only. Herein, we report a case of primary unclassified cardiac sarcoma with clinical and echocardiographic manifestations of mitral stenosis (MS). The tumor was not identified by TTE preoperatively because of its diffuse infiltration of the left atrial wall and both mitral leaflets without protruding mass, and was only discovered by intraoperative transesophageal echocardiography (TEE). This report alerts clinicians that TEE is a necessary adjunctive tool to facilitate the correct diagnosis in patients with obscure etiologies of mitral valve diseases especially when they will receive surgical intervention. [ABSTRACT FROM AUTHOR]

We report the prevalence and characteristics of Salmonella strains resistant to ciprofloxacin and extended-spectrum cephalosporins in Taiwan from January to May 2004. All isolates resistant to extended-spectrum cephalosporins carried blaCMY-2 and all ciprofloxacin-resistant Salmonella enterica serotype Choleraesuis isolates were genetically related. [ABSTRACT FROM AUTHOR]

Objectives: This study was conducted to investigate the occurrence of 16S rRNA methylases that confer high-level aminoglycoside resistance in Klebsiella pneumoniae and Escherichia coli isolates from two Taiwanese hospitals and the characteristics of these isolates.Methods: A total of 1624 K. pneumoniae and 2559 E. coli isolates consecutively collected over an 18 month period from a university hospital and seven E. coli and eight K. pneumoniae isolates that were resistant to amikacin from a district hospital were analysed. Two 16S rRNA methylase genes, armA and rmtB, were detected by PCR-based assays. -Lactamase characteristics were determined by phenotypic and genotypic methods.Results: Overall, 28 armA-positive and seven rmtB-positive isolates were identified, and extended-spectrum -lactamases (ESBLs) were detected in 33 (94.3%) isolates. The prevalence rates of armA and rmtB at the university hospital were 0.9% (n=15) and 0.3% (n=5) in K. pneumoniae and 0.4% (n=10) and 0.04% (n=1) in E. coli. CTX-M-3, CTX-M-14, SHV-5-like ESBLs, and CMY-2 were detected alone or in combination in 21, 6, 11, and 2, respectively, of the 28 armA-positive isolates. CTX-M-14 was detected in six of the seven rmtB-positive isolates. Fingerprinting of conjugative plasmids revealed the dissemination of closely related plasmids containing both armA and blaCTX-M-3. PFGE suggests that armA and rmtB spread by both horizontal transfer and clonal spread.Conclusions: This is the first report of the emergence of 16S rRNA methylases in Enterobacteriaceae in Taiwan. The spread of the multidrug-resistant isolates producing both ESBLs and 16S rRNA methylases may become a clinical problem. [ABSTRACT FROM AUTHOR]

We evaluated the disk susceptibility data of 671 nontyphoid Salmonella isolates collected from different parts of Taiwan from March 2001 to August 2001 and 1,261 nontyphoid Salmonella isolates from the National Taiwan University Hospital from 1996 to 2001. Overall, ciprofloxacin resistance was found in 2.7% (18/671)of all nontyphoid Salmonella isolates, in 1.4% (5/347) of Salmonella enterica serotype Typhimurium and in 7.5% (8/107) in S. enterica serotype Choleraesuis nationwide. MICs of six newer fluoroquinolones were determined for the following isolates: 37 isolates of ciprofloxacin-resistant (human) S. Typhimurium (N = 26) and Choleraesuis (N = 11), 10 isolates of ciprofloxacin-susceptible (MIC <1 mg/mL) (human) isolates of these two serotypes, and 15 swine isolates from S. Choleraesuis (N = 13) and Typhmurium (N = 2) with reduced susceptibility to ciprofioxacin (MIC >0.12 µg/mL). Sequence analysis of the gryA, gyrB, parC, parE, and acrR genes, ciprofioxacin accumulation, and genotypes generated by pulsed-field gel electrophoresis with three restriction enzymes (Spel, Xbal, and Blnl) were performed. All 26 S. Typhimurium isolates from humans and pigs belonged to genotype I. For S. Choleraesuis isolates, 91% (10/11) of human isolates and 54% (7/13) of swine isolates belonged to genotype B. These two genotypes isolates from humans all exhibited a high-level of resistance to ciprofloxacin (MIC 16-64 mg/mL). They had two-base substitutions in the gyrA gene at codons 83 (Ser83Phe) and 87 (Asp87Gly or Asp87Asn) and in the parc gene at codon 80 (Ser80Arg, Ser80lle, or Ser84Lys). Our investigation documented that not only did these two S. enterica isolates have a high prevalence of ciprofloxacin resistance nationwide but also that some closely related ciprofloxacin-resistant strains are disseminated from pigs to humans. [ABSTRACT FROM AUTHOR]

Presents a study which examined the emergence of ceftriaxone-resistant Salmonella isolates and rapid spread of plasmid-encoded CMY-2-like cephalosporinase in Taiwan. Materials and methods; Results; Discussion.

Experimental infection with enterovirus type 71 (EV71) induced death in neonatal mice in an age- and dose-dependent manner. The mortality rate was 100% following intraperitoneal inoculation 1-day-old ICR mice and this gradually decreased as the age at the time of inoculation increased (60% in 3-day-old mice and no deaths occurred in mice older than 6 days of age). A lethal dose greater than 10[sup 8] PFU was necessary. Lethargy, failure to gain weight, rear limb tremors and paralysis were observed in the infected mice before death. EV71 was isolated from various tissues of the dead mice. Using a reverse transcription polymerase chain reaction technique with a specific primer pair, a 332-bp product was detected in the tissues that produced a culture positive for EV71. Protection against EV71 challenge in neonatal mice was demonstrated following passive transfer of serum from actively immunized adult mice 1 day after inoculation with the virus. Pups from hyperimmune dams were resistant to EV71 challenge. Additionally, maternal immunization with a formalin-inactivated whole-virus vaccine prolonged the survival of pups after EV71 lethal challenge.Copyright © 2000 National Science Council, ROC and S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objectives: The potential therapeutic role of meropenem combined with sulbactam against a clinical endemic isolate of multidrug-resistant Acinetobacter baumannii, Ab-153, was investigated. Methods: The antimicrobial susceptibility of Ab-153 to various drugs was studied by the agar dilution method and Etest strips. The antibacterial activity of meropenem and sulbactam were investigated by a time-kill study in vitro and further examined for therapeutic efficacy in vivo in a murine model. Results: In the time-kill study, at a concentration of 0.5 × MIC (4 mg/L) of meropenem, 1 × MIC (8 mg/L) of sulbactam and both in combination, only the combination demonstrated bactericidal effects and there was at least a 5 log10 reduction in bacterial colony counts after 48 h, compared with either drug alone. BALB/c mice infected with 2.1-2.6 × 107 cfu of Ab-153 were treated with 20 mg/kg meropenem every 8 h, 40 mg/kg sulbactam every 8 h or both in combination. The survival rate of mice in the combination group was significantly higher than that in the meropenem-treated or sulbactam-treated group (87% versus 35%, P = 0.0004; 87% versus 30%, P = 0.0002). Conclusions: Meropenem in conjunction with sulbactam can exhibit more potent antimicrobial activity against Ab-153 than meropenem or sulbactam alone. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor reporting a case of drug-resistant Mycobacterium tuberculosis in Taiwan.

: Objectives The aim of this study was to determine the prevalence and characteristics of qnr-carrying Salmonella isolates from humans in southern Taiwan. : Methods A total of 446 Salmonella isolates collected between 2003 and 2006 were screened for qnrA, qnrB and qnrS by PCR experiments. Genetic structures of qnr were determined by PCR-based methods or direct sequencing of plasmid DNA. : Results qnrB2 and qnrS1 were detected in two serovar Enteritidis isolates and two serovar Typhimurium isolates, respectively. One qnrS1-positive isolate was found to produce the CMY-2 AmpC enzyme. qnrS1 was identified on a 10 kb plasmid, which exhibited >99% nucleotide sequence identity with plasmid TPqnrS-1a reported from the UK. qnrB2 was found in a complex sul1-type class 1 integron on a >100 kb plasmid. : Conclusions This study demonstrated the occurrence of qnrB2 and qnrS1 in Salmonella for the first time in Taiwan and characterized their genetic structures. [ABSTRACT FROM AUTHOR]

Objectives To determine the prevalence and characteristics of bloodstream isolates of Escherichia coli and Klebsiella pneumoniae with qnr genes in a Taiwanese hospital. Methods A total of 2035 E. coli and 1147 K. pneumoniae isolates collected between 1999 and 2005 were screened for qnrA, qnrB and qnrS by PCR and colony hybridization. β-Lactamase genes, genetic relatedness and transferability were examined by PCR, PFGE and conjugation, respectively. Results The prevalence of qnr genes was 7.8% and 0.6% for K. pneumoniae and E. coli, respectively. The prevalence rates of qnrB2, qnrB4 and qnrS1 genes for K. pneumoniae were 2.3%, 3.6% and 2.8%, respectively, and for E. coli were 0.2%, 0% and 0.4%, respectively. The prevalence of qnrB4 in K. pneumoniae increased remarkably from 0% to 7.6% over the 7 study years. qnrA was not detected. Overall, the SHV-5-related, CTX-M-14, CTX-M-3, CMY-2, DHA-1 and IMP-8 β-lactamases were detected alone or in combination in 82.0% of qnr-positive K. pneumoniae isolates and 41.7% of qnr-positive E. coli isolates. Notably, all qnrB4-positive isolates possessed the DHA-1 enzyme, and the majority of the qnrB2-positive isolates (E. coli, 100%; K. pneumoniae, 80.8%) produced SHV-5-related β-lactamases. Genetic diversity was demonstrated by PFGE. Conjugation experiments revealed co-transfer of blaSHV-12, blaDHA-1 and blaSHV-5 with qnrB2, qnrB4 and qnrS1, respectively. Conclusions qnr genes remained rare in E. coli but appeared to be increasing in K. pneumoniae in our hospital. Horizontal transfer may play a major role in the intra-hospital spread of qnr. [ABSTRACT FROM AUTHOR]

: Objectives To investigate characteristics of nine carbapenem-non-susceptible (CP-NS) Escherichia coli isolates collected between 1999 and 2005 at a Taiwanese university hospital. : Methods Genetic relatedness was analysed by PFGE. β-Lactamases were characterized by PCR and isoelectric focusing. Outer membrane proteins and transcripts were investigated by SDS–PAGE and northern blotting. Cloning experiments were performed to investigate the role of membrane permeability in carbapenem non-susceptibility. : Results The nine CP-NS isolates were found to produce the CMY-2 AmpC enzyme (n = 8), the CTX-M-14-type extended-spectrum β-lactamase (ESBL) (n = 1), the SHV-12 ESBL (n = 1) and the IMP-8-type metallo-β-lactamase (n = 1) alone or in combination. All CP-NS isolates revealed a decrease in the transcription and protein expression of ompC, and susceptibility to carbapenems was restored in one isolate by introducing the cloned ompC gene. PFGE revealed genetic diversity among the nine isolates. All patients with the CP-NS isolates had been treated with carbapenems (six patients) and/or extended-spectrum cephalosporins (five patients) before isolation. : Conclusions Our study suggests that the decreased susceptibility to carbapenems in E. coli in the hospital might arise by the stepwise accumulations of multiple drug-resistance determinants in different clones. [ABSTRACT FROM AUTHOR]