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author:("hsieh, Po-Ren")
1.  Antifungal Susceptibilities of Candida Isolates Causing Bloodstream Infections at a Medical Center in Taiwan, 2009-2010 
We used the Sensititre YeastOne (SYO) method (Trek Diagnostic Systems) to determine the MICs of nine antifungal agents against 474 nonduplicate blood Candida isolates. The MIC results were interpreted according to updated clinical breakpoints (CBPs) recommended by the Clinical and Laboratory Standards Institute (CLSI; document M27-S4) or epidemiology cutoff values (ECVs). The rates of fluconazole susceptibility were 99.2% (234/236) in Candida albicans, 86.7% (85/98) in C. tropicalis, and 97.7% (42/43) in C. parapsilosis. Among the 77 isolates of C. glabrata, 90.9% showed dose-dependent susceptibility (S-DD) to fluconazole. Nearly all isolates of C. albicans, C. parapsilosis, and C. krusei were susceptible to voriconazole; however, rates of voriconazole susceptibility were 78.6% in C. tropicalis. Few isolates of C. albicans (n = 5; 2.1%) and C. glabrata (n = 3; 3.9%), no isolates of C. parapsilosis, C. krusei, and C. guilliermondii, but 62.2% (n = 51) of C. tropicalis isolates were non-wild type for posaconazole susceptibility. For itraconazole susceptibility, 98.3% of C. albicans isolates were wild type, and 3.9% (n = 3) of C. glabrata isolates were non-wild type. Almost all of the isolates tested (>97% for all species) were susceptible to both micafungin and anidulafungin. All isolates tested were found to be wild type for amphotericin B susceptibility, with MICs of <1μg/ml. Further evaluation is needed to establish CBPs of antifungal agents by the 24-h SYO method for the management of patients with candidemia or other invasive candida infections.
doi:10.1128/AAC.01035-13
PMCID: PMC4068559  PMID: 24752274
2.  Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Nocardia, Rhodococcus, Kocuria, Gordonia, Tsukamurella, and Listeria Species 
Journal of Clinical Microbiology  2014;52(7):2371-2379.
We evaluated whether the Bruker Biotyper matrix-associated laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system provides accurate species-level identifications of 147 isolates of aerobically growing Gram-positive rods (GPRs). The bacterial isolates included Nocardia (n = 74), Listeria (n = 39), Kocuria (n = 15), Rhodococcus (n = 10), Gordonia (n = 7), and Tsukamurella (n = 2) species, which had all been identified by conventional methods, molecular methods, or both. In total, 89.7% of Listeria monocytogenes, 80% of Rhodococcus species, 26.7% of Kocuria species, and 14.9% of Nocardia species (n = 11, all N. nova and N. otitidiscaviarum) were correctly identified to the species level (score values, ≥2.0). A clustering analysis of spectra generated by the Bruker Biotyper identified six clusters of Nocardia species, i.e., cluster 1 (N. cyriacigeorgica), cluster 2 (N. brasiliensis), cluster 3 (N. farcinica), cluster 4 (N. puris), cluster 5 (N. asiatica), and cluster 6 (N. beijingensis), based on the six peaks generated by ClinProTools with the genetic algorithm, i.e., m/z 2,774.477 (cluster 1), m/z 5,389.792 (cluster 2), m/z 6,505.720 (cluster 3), m/z 5,428.795 (cluster 4), m/z 6,525.326 (cluster 5), and m/z 16,085.216 (cluster 6). Two clusters of L. monocytogenes spectra were also found according to the five peaks, i.e., m/z 5,594.85, m/z 6,184.39, and m/z 11,187.31, for cluster 1 (serotype 1/2a) and m/z 5,601.21 and m/z 11,199.33 for cluster 2 (serotypes 1/2b and 4b). The Bruker Biotyper system was unable to accurately identify Nocardia (except for N. nova and N. otitidiscaviarum), Tsukamurella, or Gordonia species. Continuous expansion of the MALDI-TOF MS databases to include more GPRs is necessary.
doi:10.1128/JCM.00456-14
PMCID: PMC4097692  PMID: 24759706
3.  Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Can Accurately Differentiate Aeromonas dhakensis from A. hydrophila, A. caviae, and A. veronii 
Journal of Clinical Microbiology  2014;52(7):2625-2628.
Among 217 Aeromonas isolates identified by sequencing analysis of their rpoB genes, the accuracy rates of identification of A. dhakensis, A. hydrophila, A. veronii, and A. caviae were 96.7%, 90.0%, 96.7%, and 100.0%, respectively, by the cluster analysis of spectra generated by matrix-assisted laser desorption ionization–time of flight mass spectrometry.
doi:10.1128/JCM.01025-14
PMCID: PMC4097716  PMID: 24759711
4.  Pulmonary Infection and Colonization with Nontuberculous Mycobacteria, Taiwan, 2000–2012 
Emerging Infectious Diseases  2014;20(8):1382-1385.
We analyzed samples from 13,652 patients who had respiratory cultures positive for mycobacteria in Taiwan during 2000–2012 and found that 56.9% were positive for nontuberculous mycobacteria (NTM). Whereas annual prevalence of tuberculosis decreased during the study period, prevalence of NTM disease and colonization increased, particularly among older patients and male patients.
doi:10.3201/eid2008.131673
PMCID: PMC4111185  PMID: 25062534
tuberculosis and other mycobacteria; bacteria; nontuberculous mycobacteria; NTM; Taiwan; pulmonary; colonization; prevalence; respiratory infections; MTB; Mycobacterium tuberculosis; isolation; infection
5.  Clostridium difficile Bacteremia, Taiwan1 
Emerging Infectious Diseases  2010;16(8):1204-1210.
C. difficile bacteremia, although uncommon, is associated with severe illness and death.
doi:10.3201/eid1608.100064
PMCID: PMC3298294  PMID: 20678312
Bacteria; Clostridium difficile; bacteremia; enteric infections; outcomes; metronidazole; vancomycin; synopsis
6.  Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry Can Accurately Differentiate between Mycobacterium masilliense (M. abscessus subspecies bolletti) and M. abscessus (Sensu Stricto) 
Journal of Clinical Microbiology  2013;51(9):3113-3116.
Among 36 Mycobacterium masilliense and 22 M. abscessus isolates identified by erm(41) PCR and sequencing analysis of rpoB and 23S rRNA genes, the rate of accurate differentiation between these two subspecies was 100% by cluster analysis of spectra generated by Bruker Biotyper matrix-assisted laser desorption ionization–time of flight mass spectrometry.
doi:10.1128/JCM.01239-13
PMCID: PMC3754645  PMID: 23824775
7.  Distribution of Extended-Spectrum β-Lactamases, AmpC β-Lactamases, and Carbapenemases among Enterobacteriaceae Isolates Causing Intra-Abdominal Infections in the Asia-Pacific Region: Results of the Study for Monitoring Antimicrobial Resistance Trends (SMART) 
The increasing trend of β-lactam resistance among Enterobacteriaceae is a worldwide threat. Enterobacteriaceae isolates causing intra-abdominal infections (IAI) from the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected in 2008 and 2009 from the Asia-Pacific region were investigated. Detection of extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, and carbapenemases was performed by multiplex PCR. A total of 699 Enterobacteriaceae isolates with positive genotypic results, included Escherichia coli (n = 443), Klebsiella pneumoniae (n = 187), Enterobacter cloacae (n = 45), Klebsiella oxytoca (n = 9), Citrobacter freundii (n = 5), Proteus mirabilis (n = 3), Enterobacter aerogenes (n = 2), Morganella morganii (n = 2), and one each of Enterobacter asburiae, Proteus vulgaris, and Providencia rettgeri were analyzed. Nearly 20% of these β-lactamase-producing Enterobacteriaceae isolates were from community-associated IAI. CTX-M (588 isolates, including 428 [72.8%] with CTX-M-15) was the most common ESBL, followed by SHV (n = 59) and TEM (n = 4). CMY (n = 110, including 102 [92.7%] with CMY-2) was the most common AmpC β-lactamase, followed by DHA (n = 46) and ACT/MIR (n = 40). NDM (n = 65, including 62 [95.4%] with NDM-1) was the most common carbapenemase, followed by IMP (n = 7) and OXA (n = 7). Isolates from hospital-associated IAI had more complicated β-lactamase combinations than isolates from the community. Carbapenemases were all exclusively detected in Enterobacteriaceae isolates from India, except that IMP β-lactamases were also detected in Philippines and Australia. CTX-M β-lactamases were the predominant ESBLs produced by Enterobacteriaceae causing IAI in the Asia-Pacific region. Emergence of CTX-M-15-, CMY-2-, and NDM-1-producing Enterobacteriaceae isolates is of major concern and highlights the need for further surveillance in this area.
doi:10.1128/AAC.00971-12
PMCID: PMC3697370  PMID: 23587958
8.  Comparison of the Accuracy of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry with That of Other Commercial Identification Systems for Identifying Staphylococcus saprophyticus in Urine 
Journal of Clinical Microbiology  2013;51(5):1563-1566.
Among 30 urinary isolates of Staphylococcus saprophyticus identified by sequencing methods, the rate of accurate identification was 100% for Bruker Biotyper matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS), 86.7% for the Phoenix PID and Vitek 2 GP systems, 93.3% for the MicroScan GP33 system, and 46.7% for the BBL CHROMagar Orientation system.
doi:10.1128/JCM.00261-13
PMCID: PMC3647924  PMID: 23390286
9.  Otitis Media and Otomastoiditis Caused by Mycobacterium massiliense (Mycobacterium abscessus subsp. bolletii) 
Journal of Clinical Microbiology  2012;50(11):3754-3756.
We describe two patients with otologic infections caused by Mycobacterium massiliense (M. abscessus subsp. bolletti) which were identified using erm(41) PCR, 23S rRNA, and rpoB gene sequence analysis. They were middle-aged adults with underlying otologic diseases and were treated successfully with clarithromycin-based combination regimens for 3 and 9 months, respectively.
doi:10.1128/JCM.01049-12
PMCID: PMC3486222  PMID: 22933592
10.  Performance Assessment of the DR. TBDR/NTM IVD Kit for Direct Detection of Mycobacterium tuberculosis Isolates, Including Rifampin-Resistant Isolates, and Nontuberculous Mycobacteria 
Journal of Clinical Microbiology  2012;50(10):3398-3401.
We evaluated the performance of the DR. TBDR/NTM IVD kit, which was designed to detect Mycobacterium tuberculosis, rifampin-resistant M. tuberculosis, and nontuberculous mycobacteria, for detecting 110 positive and 50 negative cultures in Mycobacterium Growth Indicator Tubes. The accuracy rate of this kit for identification of Mycobacterium species was 95.5% (105/110).
doi:10.1128/JCM.01862-12
PMCID: PMC3457463  PMID: 22855520
11.  Evaluation of the Bruker Biotyper Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry System for Identification of Blood Isolates of Acinetobacter Species 
Journal of Clinical Microbiology  2014;52(8):3095-3100.
Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) (Bruker Biotyper) was able to accurately identify 98.6% (142/144) of Acinetobacter baumannii isolates, 72.4% (63/87) of A. nosocomialis isolates, and 97.6% (41/42) of A. pittii isolates. All Acinetobacter junii, A. ursingii, A. johnsonii, and A. radioresistens isolates (n = 28) could also be identified correctly by Bruker Biotyper.
doi:10.1128/JCM.01233-14
PMCID: PMC4136134  PMID: 24899038
12.  Recurrent Bacteremia Caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii Complex 
Journal of Clinical Microbiology  2012;50(9):2982-2986.
This study investigated the clinical and microbiological characteristics of patients with recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex at a medical center. All ACB complex isolates associated with recurrent bacteremia were identified to the genomic species level using a 16S-23S rRNA gene intergenic spacer sequence-based method. Genotypes were determined by the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR and by pulsotypes generated by pulsed-field gel electrophoresis. Relapse of infection was defined as when the genotype of the recurrent isolate was identical to that of the original infecting strain. Reinfection was defined as when the genospecies or genotype of the recurrent isolate differed from that of the original isolate. From 2006 to 2008, 446 patients had ACB complex bacteremia and 25 (5.6%) had recurrent bacteremia caused by the ACB complex. Among the 25 patients, 12 (48%) had relapse of bacteremia caused by A. nosocomialis (n = 7) or A. baumannii (n = 5). Among the 13 patients with reinfection, 5 (38.5%) had reinfection caused by different genospecies of the ACB complex. Most of the patients were immunocompromised, and most of the infection foci were catheter-related bloodstream infections. The overall in-hospital mortality rate was 33.3%. A. baumannii isolates had lower antimicrobial susceptibility rates than A. nosocomialis and A. pittii isolates. In conclusion, relapse of ACB complex bacteremia can develop in immunocompromised patients, especially those with central venous catheters. Molecular methods to identify the ACB complex to the genospecies level are essential for differentiating between reinfection and relapse of bacteremia caused by the ACB complex.
doi:10.1128/JCM.01194-12
PMCID: PMC3421778  PMID: 22760035
13.  Characterizations of Clinical Isolates of Clostridium difficile by Toxin Genotypes and by Susceptibility to 12 Antimicrobial Agents, Including Fidaxomicin (OPT-80) and Rifaximin: a Multicenter Study in Taiwan 
A total of 403 nonduplicate isolates of Clostridium difficile were collected at three major teaching hospitals representing northern, central, and southern Taiwan from January 2005 to December 2010. Of these 403 isolates, 170 (42.2%) were presumed to be nontoxigenic due to the absence of genes for toxins A or B or binary toxin. The remaining 233 (57.8%) isolates carried toxin A and B genes, and 39 (16.7%) of these also had binary toxin genes. The MIC90 of all isolates for fidaxomicin and rifaximin was 0.5 μg/ml (range, ≤0.015 to 0.5 μg/ml) and >128 μg/ml (range, ≤0.015 to >128 μg/ml), respectively. All isolates were susceptible to metronidazole (MIC90 of 0.5 μg/ml; range, ≤0.03 to 4 μg/ml). Two isolates had reduced susceptibility to vancomycin (MICs, 4 μg/ml). Only 13.6% of isolates were susceptible to clindamycin (MIC of ≤2 μg/ml). Nonsusceptibility to moxifloxacin (n = 81, 20.1%) was accompanied by single or multiple mutations in gyrA and gyrB genes in all but eight moxifloxacin-nonsusceptible isolates. Two previously unreported gyrB mutations might independently confer resistance (MIC, 16 μg/ml), Ser416 to Ala and Glu466 to Lys. Moxifloxacin-resistant isolates were cross-resistant to ciprofloxacin and levofloxacin, but some moxifloxacin-nonsusceptible isolates remained susceptible to gemifloxacin or nemonoxacin at 0.5 μg/ml. This study found the diversity of toxigenic and nontoxigenic strains of C. difficile in the health care setting in Taiwan. All isolates tested were susceptible to metronidazole and vancomycin. Fidaxomicin exhibited potent in vitro activity against all isolates tested, while the more than 10% of Taiwanese isolates with rifaximin MICs of ≥128 μg/ml raises concerns.
doi:10.1128/AAC.00191-12
PMCID: PMC3393409  PMID: 22508299
14.  Cronobacter Infections Not from Infant Formula, Taiwan 
Emerging Infectious Diseases  2013;19(1):167-169.
doi:10.3201/eid1901.120774
PMCID: PMC3557994  PMID: 23260041
Cronobacter sakazakii; infection; Taiwan; bacteria; adults; immunocompromised; infant formula
15.  Carbapenem Therapy for Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Escherichia coli or Klebsiella pneumoniae: Implications of Ertapenem Susceptibility 
A retrospective study was conducted at two medical centers in Taiwan to evaluate the clinical characteristics, outcomes, and risk factors for mortality among patients treated with a carbapenem for bacteremia caused by extended-spectrum-beta-lactamase (ESBL)-producing organisms. A total of 251 patients with bacteremia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates treated by a carbapenem were identified. Among these ESBL-producing isolates, rates of susceptibility to ertapenem (MICs ≤ 0.25 μg/ml) were 83.8% and 76.4%, respectively; those to meropenem were 100% and 99.3%, respectively; and those to imipenem were 100% and 97.9%, respectively. There were no significant differences in the critical illness rate (P = 0.1) or sepsis-related mortality rate (P = 0.2) for patients with bacteremia caused by ESBL-producing K. pneumoniae (140 isolates, 55.8%) and E. coli (111 isolates, 44.2%). Multivariate analysis of variables related to sepsis-related mortality revealed that the presence of severe sepsis (odds ratio [OR], 15.9; 95% confidence interval [CI], 5.84 to 43.34; P < 0.001), hospital-onset bacteremia (OR, 4.65; 95% CI, 1.42 to 15.24; P = 0.01), and ertapenem-nonsusceptible isolates (OR, 5.12; 95% CI, 2.04 to 12.88; P = 0.001) were independent risk factors. The patients receiving inappropriate therapy had a higher sepsis-related mortality than those with appropriate therapy (P = 0.002), irrespective of ertapenem, imipenem, or meropenem therapy. Infections due to the ertapenem-susceptible isolates (MICs ≤ 0.25 μg/ml) were associated with a more favorable outcome than those due to ertapenem-nonsusceptible isolates (MICs > 0.25 μg/ml), if treated by a carbapenem. However, the mortality for patients with bacteremic episodes due to isolates with MICs of ≤0.5 μg/ml was similar to the mortality for those whose isolates had MICs of >0.5 μg/ml (P = 0.8). Such a finding supports the rationale of the current CLSI 2011 criteria for carbapenems for Enterobacteriaceae.
doi:10.1128/AAC.06301-11
PMCID: PMC3370719  PMID: 22430969
16.  Trends in Susceptibility of Vancomycin-Resistant Enterococcus faecium to Tigecycline, Daptomycin, and Linezolid and Molecular Epidemiology of the Isolates: Results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) Study, 2006 to 2010 
Among the 219 vancomycin-resistant Enterococcus faecium isolates collected in 20 Taiwanese hospitals from 2006 to 2010, all were susceptible to linezolid and daptomycin, and 98.6% were susceptible to tigecycline. There was a shift toward higher tigecycline MIC values (MIC90s) from 2006-2007 (0.06 μg/ml) to 2008–2010 (0.12 μg/ml). The MIC90s of daptomycin and linezolid remained stationary. Although pulsotypes among the isolates from the 20 hospitals varied, intrahospital spreading of several clones was identified in 13 hospitals.
doi:10.1128/AAC.00533-12
PMCID: PMC3370810  PMID: 22491684
17.  Clinical and Microbiological Characteristics of Bacteremia Caused by Eggerthella, Paraeggerthella, and Eubacterium Species at a University Hospital in Taiwan from 2001 to 2010 
Journal of Clinical Microbiology  2012;50(6):2053-2055.
We describe 16 patients with bacteremia caused by Eggerthella lenta (n = 7), Paraeggerthella hongkongensis (n = 3), Eubacterium limosum (n = 4), Eubacterium callanderi (n = 1), and concomitant Eubacterium limosum/Eggerthella lenta (n = 1). Nine (56%) patients had polymicrobial bacteremia. The overall 60-day mortality rate was 19%, and all deaths occurred in patients with E. lenta bacteremia.
doi:10.1128/JCM.00548-12
PMCID: PMC3372111  PMID: 22495556
18.  Cutaneous Infection Caused by Gordonia amicalis after a Traumatic Injury 
Journal of Clinical Microbiology  2012;50(5):1821-1822.
Gordonia amicalis infection has never been reported in humans. We report here the first case of G. amicalis-related cutaneous infection after a traumatic injury. The isolate was confirmed by 16S rRNA sequencing analysis, and the patient responded well to repeated debridement and antibiotic treatment.
doi:10.1128/JCM.06681-11
PMCID: PMC3347127  PMID: 22337976
19.  Agreement Assessment of Tigecycline Susceptibilities Determined by the Disk Diffusion and Broth Microdilution Methods among Commonly Encountered Resistant Bacterial Isolates: Results from the Tigecycline In Vitro Surveillance in Taiwan (TIST) Study, 2008 to 2010 
The Tigecycline In Vitro Surveillance in Taiwan (TIST) study, initiated in 2006, is a nationwide surveillance program designed to longitudinally monitor the in vitro activity of tigecycline against commonly encountered drug-resistant bacteria. This study compared the in vitro activity of tigecycline against 3,014 isolates of clinically important drug-resistant bacteria using the standard broth microdilution and disk diffusion methods. Species studied included methicillin-resistant Staphylococcus aureus (MRSA; n = 759), vancomycin-resistant Enterococcus faecium (VRE; n = 191), extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (n = 602), ESBL-producing Klebsiella pneumoniae (n = 736), and Acinetobacter baumannii (n = 726) that had been collected from patients treated between 2008 and 2010 at 20 hospitals in Taiwan. MICs and inhibition zone diameters were interpreted according to the currently recommended U.S. Food and Drug Administration (FDA) criteria and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. The MIC90 values of tigecycline against MRSA, VRE, ESBL-producing E. coli, ESBL-producing K. pneumoniae, and A. baumannii were 0.5, 0.125, 0.5, 2, and 8 μg/ml, respectively. The total error rates between the two methods using the FDA criteria were high: 38.4% for ESBL-producing K. pneumoniae and 33.8% for A. baumannii. Using the EUCAST criteria, the total error rate was also high (54.6%) for A. baumannii isolates. The total error rates between these two methods were <5% for MRSA, VRE, and ESBL-producing E. coli. For routine susceptibility testing of ESBL-producing K. pneumoniae and A. baumannii against tigecycline, the broth microdilution method should be used because of the poor correlation of results between these two methods.
doi:10.1128/AAC.05879-11
PMCID: PMC3294924  PMID: 22155819
20.  Trends in the Susceptibility of Clinically Important Resistant Bacteria to Tigecycline: Results from the Tigecycline In Vitro Surveillance in Taiwan Study, 2006 to 2010 
The Tigecycline In Vitro Surveillance in Taiwan (TIST) study, a nationwide, prospective surveillance during 2006 to 2010, collected a total of 7,793 clinical isolates, including methicillin-resistant Staphylococcus aureus (MRSA) (n = 1,834), penicillin-resistant Streptococcus pneumoniae (PRSP) (n = 423), vancomycin-resistant enterococci (VRE) (n = 219), extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (n = 1,141), ESBL-producing Klebsiella pneumoniae (n = 1,330), Acinetobacter baumannii (n = 1,645), and Stenotrophomonas maltophilia (n = 903), from different specimens from 20 different hospitals in Taiwan. MICs of tigecycline were determined following the criteria of the U.S. Food and Drug Administration (FDA) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST-2011). Among drug-resistant Gram-positive pathogens, all of the PRSP isolates were susceptible to tigecycline (MIC90, 0.03 μg/ml), and only one MRSA isolate (MIC90, 0.5 μg/ml) and three VRE isolates (MIC90, 0.125 μg/ml) were nonsusceptible to tigecycline. Among the Gram-negative bacteria, the tigecycline susceptibility rates were 99.65% for ESBL-producing E. coli (MIC90, 0.5 μg/ml) and 96.32% for ESBL-producing K. pneumoniae (MIC90, 2 μg/ml) when interpreted by FDA criteria but were 98.7% and 85.8%, respectively, when interpreted by EUCAST-2011 criteria. The susceptibility rate for A. baumannii (MIC90, 4 μg/ml) decreased from 80.9% in 2006 to 55.3% in 2009 but increased to 73.4% in 2010. A bimodal MIC distribution was found among carbapenem-susceptible A. baumannii isolates, and a unimodal MIC distribution was found among carbapenem-nonsusceptible A. baumannii isolates. In Taiwan, tigecycline continues to have excellent in vitro activity against several major clinically important drug-resistant bacteria, with the exception of A. baumannii.
doi:10.1128/AAC.06053-11
PMCID: PMC3294947  PMID: 22203598
21.  Increase in the rate of azithromycin-resistant Streptococcus pneumoniae isolates carrying the erm(B) and mef(A) genes in Taiwan, 2006–2010 
BMC Infectious Diseases  2014;14(1):704.
Background
This study investigated the molecular characteristics of azithromycin-resistant Streptococcus pneumoniae in Taiwan.
Methods
A total of 486 non-duplicate isolates of azithromycin-resistant S. pneumoniae recovered from various clinical sources of patients treated at 22 different hospitals in Taiwan from 2006 to 2010. The presence of erm(B) and mef(A) genes using duplex PCR, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis of these isolates were studied.
Results
Of the isolates tested, 59% carried the erm(B) gene, 22% carried the mef(A) gene, and 19% carried both genes. The prevalence of isolates carrying the erm(B) and mef(A) genes increased from 10% (11/110) in 2006 to 25% (15/60) in 2010 (p-value = 0.0136). The majority of isolates carrying both erm(B) and mef(A) genes belonged to serotypes 19 F (64%) followed by 19 F A (24%). Of these isolates, 33% were sequence type 320 (ST320), 32% were ST236, and 12% were ST271.
Conclusions
The increase in incidence of mef(A)/erm(B)-positive azithromycin-resistant S. pneumoniae isolates during the study period was primarily due to serotypes 19 F and 19A and ST236 and ST320.
doi:10.1186/s12879-014-0704-z
PMCID: PMC4279982  PMID: 25527193
Streptococcus pneumoniae; Azithromycin-resistant; Tigecycline In Vitro Surveillance in Taiwan (TIST) study
22.  Risk factors and clinical characteristics of patients with qnr-positive Klebsiella pneumoniae bacteraemia 
Journal of Antimicrobial Chemotherapy  2013;68(12):2907-2914.
Objectives
Plasmid-mediated quinolone resistance (PMQR) caused by qnr genes has been known for 15 years. Information about global distribution and prevalence of qnr genes is abundant, but clinical information concerning infections produced by these isolates and risk factors for their acquisition is limited.
Methods
Klebsiella pneumoniae blood isolates (n = 227) from a 1 year prospective cohort of patients in Taiwan were studied. MICs of quinolones were determined for all isolates, and multiplex PCR for the presence of PMQR genes and DNA gyrase mutations was applied to all 24 isolates with ciprofloxacin MICs ≥0.12 mg/L and a control group of 72 isolates with MICs ≤0.06 mg/L.
Results
All qnr isolates were in the group with ciprofloxacin MICs ≥0.12 mg/L, constituting 9.4% of tested isolates and 3.9% (qnrB 2.6% and qnrS 1.3%) of total isolates. aac(6′)-Ib-cr and qepA were not found. Risk factors for qnr included nosocomial infection, bedridden status, surgery within 3 months, non-K1/K2 serotypes and prior antimicrobial use. Ciprofloxacin MIC ≥0.12 mg/L was associated with prior quinolone use; in contrast, prior cephalosporin use was more closely linked to the presence of qnr. Fourteen-day mortality was similar in patients infected with qnr-positive versus qnr-negative isolates, but there was a trend for increased in-hospital mortality in patients infected with qnr-positive isolates.
Conclusions
In K. pneumoniae blood isolates collected at a hospital in Taiwan, the overall prevalence of qnr genes was 3.9%. Prior quinolone use was linked to increased ciprofloxacin MIC, but not with the prevalence of qnr, which was most strongly linked to exposure to other antimicrobials, especially cephalosporins.
doi:10.1093/jac/dkt295
PMCID: PMC3820109  PMID: 23956373
K. pneumoniae; PMQR; resistance
23.  Brucellosis, Taiwan, 2011 
Emerging Infectious Diseases  2011;17(12):2374-2375.
doi:10.3201/eid1712.110739
PMCID: PMC3311202  PMID: 22172150
Brucellosis; Taiwan; zoonoses; bacteria
24.  Disseminated Mycobacterium abscessus Infection and Showerheads, Taiwan 
Emerging Infectious Diseases  2011;17(11):2077-2078.
doi:10.3201/eid1711.110050
PMCID: PMC3310555  PMID: 22099106
Mycobacterium abscessus; bacteremic lymphadenitis; Sjögren syndrome; showerheads; bacteria; Taiwan; letter
25.  Antimicrobial Susceptibilities and Molecular Epidemiology of Clinical Isolates of Clostridium difficile in Taiwan▿  
The antimicrobial susceptibility and virulence factors of Clostridium difficile clinical isolates in Taiwan have not previously been reported. One hundred and thirteen isolates were collected from two major teaching hospitals in Taiwan from 2001 to 2009. Molecular typing was performed by an automated repetitive extragenic palindromic sequence-based PCR (rep-PCR) method (DiversiLab; Bacterial Barcodes, Inc., Athens, GA) and PCR ribotyping. Detection of tcdA, tcdB, cdtA, and cdtB genes was performed using a multiplex PCR assay, and gyrA and gyrB genes of moxifloxacin-nonsusceptible isolates were sequenced. All isolates were susceptible to vancomycin and metronidazole. Ninety-five (84%) isolates were susceptible to moxifloxacin, and the MIC90 for nemonoxacin was 4 μg/ml. Tigecycline showed favorable antibacterial activity (MIC90 of 0.06 μg/ml). Thirteen rep-PCR types were identified as a predominant rep-PCR type (type A; non-North American pulsed-field gel electrophoresis type 1 [NAP1], -NAP7, or -NAP8) accounting for 52.2% (59 isolates). Nine of 18 moxifloxacin-nonsusceptible isolates belonged to the rep-PCR type A. The rep-PCR type A and C isolates were distinct from NAP1 (ribotype 027) and NAP8 (ribotype 078) as determined by PCR ribotyping. Seventy-four (65%) isolates harbored tcdA and tcdB, and 15 (13%) harbored cdtAB encoding binary toxin. Eleven isolates had a gene deletion in tcdC, including a 39-bp deletion (9 isolates) and an 18-bp deletion (2). In conclusion, dissemination of a predominant C. difficile clone in southern and northern Taiwan was noted. However, no NAP1 (ribotype 027) isolate could be discovered in this study.
doi:10.1128/AAC.01440-10
PMCID: PMC3067156  PMID: 21263053

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