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Wu LT, Nguyen HTV, Ke SC, Lin YP, Pang YC, Guo MK, Chen CM. High Prevalence of Carbapenem-Resistant Enterobacterales Producing OXA-48 among Carbapenem-Resistant Isolates in a Regional Hospital in Central Taiwan. Jpn J Infect Dis 2024; 77:83-90. [PMID: 38030272 DOI: 10.7883/yoken.jjid.2023.213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
In response to the increasing number of carbapenem-resistant Enterobacterales (CRE), we investigated carbapenemase-producing Klebsiella pneumoniae and non-K. pneumoniae epidemiology and genetics. We collected 76 clinical Enterobacterales and 4 stool surveillance Escherichia coli isolates resistant to ertapenem or imipenem. Using polymerase chain reaction (PCR) and DNA sequencing, we assessed carbapenemases, extended-spectrum β-lactamases, and AmpC β-lactamases. Molecular typing via pulsed-field gel electrophoresis (PFGE) and conjugation experiments were conducted to examine resistance gene transfer. Among the 80 isolates, 96.2% harbored at least one carbapenemase gene, with blaOXA-48 in 87.5%. KPC-2 and IMP-8 carbapenemases were found in 15.0 and 22.5% of the isolates, respectively, with 27.5% having 2 or more carbapenemase genes. The PFGE analysis revealed the presence of diverse genotypes. PCR-based plasmid replicon typing identified IncA/C as the most prevalent type among K. pneumoniae isolates (26/29), and IncF and IncFIB among E. coli isolates (22/28). Conjugal transfer was successful for plasmids encoding OXA-48, CTX-M-3, CTX-M-14, CMY-2, and other β-lactamases, except the KPC-2 gene. In conclusion, our study highlights high carbapenemase prevalence in CRE, primarily OXA-48. Multiple carbapenemases within strains were common, and PFGE showed diverse patterns in these carbapenem-resistant isolates.
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Affiliation(s)
- Lii-Tzu Wu
- The Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taiwan
| | - Hong-Thuy Vy Nguyen
- The Institute of Biomedical Sciences College of Medicine, China Medical University, Taiwan
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taiwan
- Department of Medical Technology, Jen-The Junior College of Medicine, Nursing and Management, Taiwan
| | - Yi-Pei Lin
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taiwan
| | - Yi-Chun Pang
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, China Medical University, Taiwan
| | - Ming-Kai Guo
- The Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taiwan
| | - Chih-Ming Chen
- Division of Infectious Diseases, Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taiwan
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Chen CM, Tang HL, Ke SC, Lin YP, Lu MC, Lai YC, Chen BH, Wang YW, Teng RH, Chiou CS. A nosocomial salmonellosis outbreak caused by blaOXA-48-carrying extensively drug-resistant Salmonella enterica serovar Goldcoast in a hospital respiratory care ward in Taiwan. J Glob Antimicrob Resist 2022; 29:331-338. [DOI: 10.1016/j.jgar.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 10/18/2022] Open
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Wu LT, Wu XX, Ke SC, Lin YP, Wu YC, Chen TH, Chen CM. Antimicrobial resistance genes and genetic characteristics of multidrug-resistant Escherichia coli in a veterinary hospital in Taiwan. J Med Microbiol 2021; 70. [PMID: 34779761 DOI: 10.1099/jmm.0.001453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Introduction. Antimicrobial resistance associated with animal hosts is easily transmitted to humans either by direct contact with resistant organisms or by transferring resistance genes into human pathogens.Gap statement. There are limited studies on antimicrobial resistance genes and genetic elements of multidrug-resistant (MDR) Escherichia coli in veterinary hospitals in Taiwan.Aim. The aim of this study was to investigate antimicrobial resistance genes in multidrug-resistant Escherichia coli from animals.Methodology. Between January 2014 and August 2015, 95 multidrug-resistant Escherichia coli isolates were obtained from pigs (n=66), avians (n=18), and other animals (n=11) in a veterinary hospital in Taiwan. Susceptibility testing to 24 antimicrobial agents of 14 antimicrobial classes was performed. Antimicrobial resistance genes, integrons, and insertion sequences were analysed by polymerase chain reaction and nucleotide sequencing. Pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing were used to explore the clonal relatedness of the study isolates.Results. Different antimicrobial resistance genes found in these isolates were associated with resistance to β-lactams, tetracycline, phenicols, sulfonamides, and aminoglycosides. Fifty-five of 95 E. coli isolates (55/95, 57.9 %) were not susceptible to extended-spectrum cephalosporins, and bla CTX-M-55 (11/55, 20.0 %) and bla CMY-2 (40/55, 72.7 %) were the most common extended-spectrum β-lactamase (ESBL) and AmpC genes, respectively. Both bla CTX-M and bla CMY-2 were present on conjugative plasmids that contained the insertion sequence ISEcp1 upstream of the bla genes. Plasmid-mediated FOX-3 β-lactamase-producing E. coli was first identified in Taiwan. Forty isolates (40/95, 42 %) with class 1 integrons showed seven resistance phenotypes. Genotyping of 95 E. coli isolates revealed 91 different XbaI pulsotypes and 52 different sequence types. PFGE analysis revealed no clonal outbreaks in our study isolates.Conclusion. This study showed a high diversity of antimicrobial resistance genes and genotypes among MDR E. coli isolated from diseased livestock in Taiwan. To our knowledge, this is the first report of plasmid-mediated ESBL in FOX-3 β-lactamase-producing E. coli isolates in Taiwan. MDR E. coli isolates from animal origins may contaminate the environment, resulting in public health concerns, indicating that MDR isolates from animals need to be continuously investigated.
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Affiliation(s)
- Lii-Tzu Wu
- Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taiwan, ROC
| | - Xin-Xia Wu
- RBC bioscience Corp, Xindian District, New Taipei City, Taiwan, ROC
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC.,Department of Medical Technology, Jen-The Junior College of Medicine, Nursing and Management, Miaoli, Taiwan, ROC
| | - Yi-Pei Lin
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC
| | - Ying-Chen Wu
- Graduate Institute of Veterinary Pathology, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Ter-Hsin Chen
- Graduate Institute of Veterinary Pathology, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Chih-Ming Chen
- Division of Infectious Diseases, Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC.,Department of Nursing, Jenteh Junior College of Medicine, Nursing and Management, Miaoli, Taiwan, ROC
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Wu LT, Guo MK, Ke SC, Lin YP, Pang YC, Nguyen HTV, Chen CM. Characterization of the Genetic Background of KPC-2-Producing Klebsiella pneumoniae with Insertion Elements Disrupting the ompK36 Porin Gene. Microb Drug Resist 2020; 26:1050-1057. [PMID: 32283046 DOI: 10.1089/mdr.2019.0410] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Lii-Tzu Wu
- The Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taichung, Taiwan
| | - Ming-Kai Guo
- The Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taichung, Taiwan
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
- Department of Medical Technology, Jen-The Junior College of Medicine, Nursing and Management, Miaoli, Taiwan
| | - Yi-Pei Lin
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Yi-Chun Pang
- The Institute of Medical Science and Department of Microbiology, China Medical University Hospital, Taichung, Taiwan
| | - Hong-Thuy Vy Nguyen
- The Institute of Biomedical Sciences College of Medicine, China Medical University, Taichung, Taiwan
| | - Chih-Ming Chen
- Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
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Chen CM, Guo MK, Ke SC, Lin YP, Li CR, Vy Nguyen HT, Wu LT. Emergence and nosocomial spread of ST11 carbapenem-resistant Klebsiella pneumoniae co-producing OXA-48 and KPC-2 in a regional hospital in Taiwan. J Med Microbiol 2019; 67:957-964. [PMID: 29873627 DOI: 10.1099/jmm.0.000771] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose. Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a major challenge for global healthcare systems. The objectives of this study were to determine the nosocomial spread of CRKP clones and analyse the molecular characteristics of CRKP in our hospital.Methodology. Ninety-eight non-duplicated clinical CRKP isolates were collected from March 2014-June 2015. Clinical, demographic and microbiological data of patients with CRKP were reviewed. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing were applied to investigate the genetic relationship between the 98 isolates. Antibiotic resistance genes were identified by conventional PCR-sequencing.Results. PFGE patterns were grouped into 26 clusters. Two main PFGE clusters were identified: L (53 isolates, belonging to ST11) and N (11 isolates, belonging to ST11). The most dominant ST was ST11 (79 %, 77/98), followed by ST273 (5 %, 5/98). KPC-2 (n=82) was the predominant carbapenemase followed by OXA-48 (n=64). Fifty isolates (51 %, 50/98) harboured bla KPC-2 and bla OXA-48 simultaneously, and three of these isolates were detected with the third carbapenemase genes (bla IMP-8 or bla VIM-1).Conclusion. The clonal spread of K. pneumoniae ST11 expressing OXA-48, KPC-2 and CTX-M-14 β-lactamases was the cause of an outbreak of CRKP. To the best of our knowledge, a single strain harbouring A-, B- and D-class carbapenemase genes has not previously been identified. There is a high prevalence of plasmid-encoded KPC-2- and OXA-48-producing CRKP in our hospital; most isolates were members of ST11, which may be representative of a high-risk CRKP clone disseminating in central Taiwan.
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Affiliation(s)
- Chih-Ming Chen
- Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC.,Department of Health Food, Chung Chou University of Science and Technology, Changhua, Taiwan, ROC
| | - Ming-Kai Guo
- The Institute of Medical Science and Department of Microbiology, China Medical University, Taichung, Taiwan, ROC
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC.,Department of Medical Technology, Jen-The Junior College of Medicine, Nursing and Management, Miaoli, Taiwan, ROC
| | - Yi-Pei Lin
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC
| | - Chia-Ru Li
- Section of Infectious Diseases, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Hong Thuy Vy Nguyen
- The Institute of Biomedical Sciences College of Medicine, China Medical University, Taichung, Taiwan, ROC
| | - Lii-Tzu Wu
- The Institute of Medical Science and Department of Microbiology, China Medical University, Taichung, Taiwan, ROC
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Chen FD, Chen HH, Ke SC, Zheng LR, Zheng XY. SLC27A2 regulates miR-411 to affect chemo-resistance in ovarian cancer. Neoplasma 2018; 65:915-924. [PMID: 30334452 DOI: 10.4149/neo_2018_180122n48] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/02/2018] [Indexed: 11/08/2022]
Abstract
Although platinum-based chemotherapies have long been used as standard treatment in ovarian cancer, cisplatin resistance is a major problem that restricts its use. Herein, we investigate the biological function of SLC27A2 and its underlying mechanisms in regulating chemo-resistance in ovarian cancer. The findings show that SLC27A2 down-regulation in primary ovarian cancer tissues correlates with chemo-resistance and poor patient survival in our patient cohort. Significantly, we demonstrate that up-regulation of SLC27A2 by lentivirus-mediated p-SLC27A2 sensitizes ovarian cancer cells to cisplatin in vitro and in vivo via apoptosis. Mechanistic investigation reveals that miR-411 is the most strikingly over-expressed gene in response to ectopic expression of SLC27A2, but under-expressed in recurrent ovarian cancer tissues. Lower miR-411 expression contributes to ovarian cancer chemo-resistance in vitro and in vivo. Furthermore, SLC27A2 directly binds specific sites in the miR-411 promoter region and promoter activity decreases after mutation of putative SLC27A2-binding sites. This indicates that SLC27A2 is required for the transcriptional induction of miR-411. The luciferase assays also confirm that miR-411 directly targets ABCG2 in ovarian cancer, and overall findings establish the SLC27A2-miR-411-ABCG2 pathway in the regulation of ovarian cancer chemo-resistance with potential therapeutic applications.
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Affiliation(s)
- F D Chen
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - H H Chen
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - S C Ke
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - L R Zheng
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - X Y Zheng
- Department of Obstetrics and Gynecology, the Third Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Chen CM, Ke SC, Li CR, Wu YC, Chen TH, Lai CH, Wu XX, Wu LT. High Diversity of Antimicrobial Resistance Genes, Class 1 Integrons, and Genotypes of Multidrug-ResistantEscherichia coliin Beef Carcasses. Microb Drug Resist 2017; 23:915-924. [DOI: 10.1089/mdr.2016.0223] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Chih-Ming Chen
- Department of Health Food, Chung Chou University of Science and Technology, Changhua, Taiwan
- Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chia-Ru Li
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Ying-Chen Wu
- Graduate Institute of Veterinary Pathology, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Ter-Hsin Chen
- Graduate Institute of Veterinary Pathology, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Ho Lai
- Institute of Basic Medical Science, School of Medicine, China Medical University and Hospital, Taichung, Taiwan
- Department of Microbiology and Immunology, Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan
- Department of Nursing, Asia University, Taichung, Taiwan
| | - Xin-Xia Wu
- Department of Microbiology, The Institute of Medical Science, China Medical University Hospital, Taichung, Taiwan
| | - Lii-Tzu Wu
- Department of Microbiology, The Institute of Medical Science, China Medical University Hospital, Taichung, Taiwan
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Chen CM, Ke SC, Li CR, Chang CC. The comparison of genotyping, antibiogram, and antimicrobial resistance genes between carbapenem-susceptible and -resistant Acinetobacter baumannii. Comp Immunol Microbiol Infect Dis 2014; 37:339-46. [PMID: 25456639 DOI: 10.1016/j.cimid.2014.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/03/2014] [Accepted: 10/07/2014] [Indexed: 11/30/2022]
Abstract
This study was conducted to explore the epidemiological and molecular differences between carbapenem-susceptible Acinetobacter baumannii (CSAB) and carbapenem-resistant A. baumannii (CRAB) isolates. Thirty-two CSAB and 55 CRAB isolates were collected in 2010. By multilocus sequence typing analysis, 31 (56%) CRAB isolates and 11 (34%) CSAB isolates belonged to ST2. Twenty-one (38%) CRAB isolates, and 4 (13%) CSAB isolates belonged to a new type, ST129. The blaIMP, blaVIM, and blaOXA-58-like were not detected in our study isolates. blaOXA-23 and blaOXA-24/40-like were not detected in all CSAB isolates. On the contrary, blaOXA-23 was detected in 51 (93%) CRAB isolates. Class 1 integron was detected in 19 (35%) CRAB isolates and 8 (25%) CSAB isolates (p>0.05). In conclusion, the ST2 and ST129 were the major sequence types in both CSAB and CRAB isolates. The blaOXA-23 is the primary carbapenem-resistance gene in CRAB isolates from hospitalized patients and the specimens collected from hospital environment.
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Affiliation(s)
- Chih-Ming Chen
- Division of Infectious Disease, Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan; Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chia-Ru Li
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chao-Chin Chang
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan.
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Chen CM, Ke SC, Li CR, Chiou CS, Chang CC. Prolonged clonal spreading and dynamic changes in antimicrobial resistance of Escherichia coli ST68 among patients who stayed in a respiratory care ward. J Med Microbiol 2014; 63:1531-1541. [PMID: 25168964 DOI: 10.1099/jmm.0.075937-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
From 2007 to 2009, we collected a total of 83 bacteraemic isolates of Escherichia coli with reduced susceptibility or resistance to third-generation cephalosporins (TGCs). Isolates were genotyped by PFGE and multilocus sequence typing (MLST). The PFGE patterns revealed two highly correlated clusters (cluster E: nine isolates; cluster G: 22 isolates) associated with this prolonged clonal spreading. Compared with cluster E isolates, cluster G isolates were significantly more likely to harbour aac(6')-Ib-cr (P<0.05), and most of these isolates were isolated during a later year than cluster E isolates (P<0.05). By MLST analysis, 94% of cluster E and G isolates (29/31) were ST68. Although no time or space clustering could be identified by the conventional hospital-acquired infection monitoring system, E. coli cases caused by cluster E and G isolates were significantly associated with having stayed in our hospital's respiratory care ward (P<0.05). Isolates obtained from patients who had stayed in the respiratory care ward had a significantly higher rate of aac(6')-Ib-cr and blaCTX-M-14 positivity, and were more likely to belong to ST68/S68-like (all P<0.05). To our knowledge, this is the first report of prolonged clonal spreading caused by E. coli ST68 associated with a stay in a long-term care facility. Using epidemiological investigations and PFGE and MLST analyses, we have identified long-term clonal spreading caused by E. coli ST68, with extra antimicrobial-resistance genes possibly acquired during the prolonged spreading period.
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Affiliation(s)
- Chih-Ming Chen
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
- Division of Infectious Disease, Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Se-Chin Ke
- Infection Control Office, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chia-Ru Li
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan
| | - Chien-Shun Chiou
- The Third Branch, Centers for Diseases Control, Taichung, Taiwan
| | - Chao-Chin Chang
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, Taiwan
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Chen CM, Huang M, Chen HF, Ke SC, Li CR, Wang JH, Wu LT. Fusidic acid resistance among clinical isolates of methicillin-resistant Staphylococcus aureus in a Taiwanese hospital. BMC Microbiol 2011; 11:98. [PMID: 21569422 PMCID: PMC3114704 DOI: 10.1186/1471-2180-11-98] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Accepted: 05/12/2011] [Indexed: 11/26/2022] Open
Abstract
Background The prevalence of resistance to fusidic acid of methicillin-resistant Staphylococcus aureus (MRSA) was increased each year in a Taiwan hospital. Thirty-four MRSA clinical isolates collected in 2007 and 2008 with reduced susceptibility to FA were selected for further evaluation the presence of resistance determinants. Results The most common resistance determinant was fusC, found in 25 of the 34 MRSA isolates. One of the 25 fusidic acid-resistant MRSA harboured both fusB and fusC, which is the first time this has been identified. Mutations in fusA were found in 10 strains, a total of 3 amino-acid substitutions in EF-G (fusA gene) were detected. Two substitutions with G556S and R659L were identified for the first time. Low-level resistance to fusidic acid (MICs, ≤ 32 μg/ml) was found in most our collection. All collected isolates carried type III SCCmec elements. MLST showed the isolates were MRSA ST239. PFGE revealed nine different pulsotypes in one cluster. Conclusions Our results indicate that the increase in the number of fusidic acid resistant among the MRSA isolates in this hospital is due mainly to the distribution of fusC determinants. Moreover, more than one fusidic acid-resistance mechanism was first detected in a same stain in our collection.
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Affiliation(s)
- Chih-Ming Chen
- Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, and Department of Microbiology, China Medical University, Taichung, Taiwan
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Chen CM, Liu PY, Ke SC, Wu HJ, Wu LT. Investigation of carbapenem-resistant Acinetobacter baumannii isolates in a district hospital in Taiwan. Diagn Microbiol Infect Dis 2009; 63:394-7. [PMID: 19302926 DOI: 10.1016/j.diagmicrobio.2008.12.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 12/08/2008] [Accepted: 12/15/2008] [Indexed: 11/18/2022]
Abstract
A total of 34 Acinetobacter baumannii isolates from a district hospital in Taiwan were identified with carbapenem-hydrolyzing oxacillinase OXA-66/OXA-51-like. In addition, 26 of 28 carbapenem-resistant isolates harbored plasmid-encoded bla(OXA-23)-like genes. Twenty of 28 carbapenem-resistant isolates mapped to the major genotype cluster A of carbapenemase producer by pulsed-field gel electrophoresis.
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Affiliation(s)
- Chih-Ming Chen
- Department of Internal Medicine, Division of Infectious Disease, Tungs' Taichung MetroHarbor Hospital, Taiwan; The Graduate Institute of Clinical Medical Science, China Medical University, Taiwan
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Abstract
The adenosylcobalamin coenzyme-dependent ethanolamine deaminase from Salmonella typhimurium catalyzes the deamination of aminoethanol to acetaldehyde and ammonia. The radical intermediate observed during steady state turnover of substrate aminoethanol has been characterized by continuous wave electron paramagnetic resonance (EPR) spectroscopy [J. Am. Chem. Soc. 121 (1999) 10522]. This study presents simulations of EPR spectra of this radical intermediate. Quantitative fits to the EPR spectra are achieved with a model of isotropic exchange and magnetic dipolar interaction between the substrate-derived radical and the Co(II) in the corrin ring. The simulated parameters are compared with those of substrate analog 2-aminopropanol-derived radical in the same enzyme. The comparison confirms that the aminoethanol-derived product radical interacts more weakly with the Co(II) than the 2-aminopropanol-derived radical and suggests that the reduction of isotropic exchange between the aminoethanol-derived product radical and the Co(II) is probably due to orientational-dependent wave function overlap. Successful fits to the radical line shapes of different isotope substitutions unequivocally establish that the observed radical intermediate is an pi-electron-based product radical. The derived principal hyperfine values for the 13C(alpha) and 1H(alpha) nucleus are consistent with previous electron nuclear double resonance (ENDOR) studies on similar radicals, thus providing reliable experimental hyperfine coupling constants for comparison with quantum mechanical-based calculations to gain further insight into the molecular structure of the observed radical.
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Affiliation(s)
- S C Ke
- Department of Physics, National Dong Hwa University, Hualien 974-01, Taiwan.
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Ke SC, Torrent M, Museav DG, Morokuma K, Warncke K. Identification of dimethylbenzimidazole axial coordination and characterization of (14)N superhyperfine and nuclear quadrupole coupling in Cob(II)alamin bound to ethanolamine deaminase in a catalytically-engaged substrate radical-Cobalt(II) biradical state. Biochemistry 1999; 38:12681-9. [PMID: 10504238 DOI: 10.1021/bi983067w] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cobalt(II)-(14)N superhyperfine and (14)N nuclear quadrupole couplings in cryotrapped free and ethanolamine deaminase-bound cob(II)alamin have been characterized in the disordered solid state by using X-band electron spin-echo envelope modulation (ESEEM) spectroscopy. Enzyme-bound cob(II)alamin was cryotrapped after formation by substrate-initiated, thermally activated cleavage of the cobalt-carbon bond of adenosylcobalamin. Free dimethylbenzimidazole axial base-on cob(II)alamin was formed by photolysis of the corresponding adenosylcobalamin and cryotrapped in glycerol-aqueous glass. Three-pulse ESEEM experiments were performed by using microwave pulse excitation at the g( perpendicular) value of Co(II) at magnetic field values of 287.0 and 345.0 mT and over a range of tau values from 227 to 1316 ns. Two common sets of (14)N features are distinguished in the ESEEM spectra. One set is assigned to the remote (N1) nitrogen in the dimethylbenzimidazole alpha-axial ligand by using two independent approaches: (a) comparison of ESEEM from cob(II)alamin with ESEEM from cob(II)inamide-ligand model compounds and (b) from the correspondence between the N1 (14)N nuclear quadrupole parameters derived from ESEEM simulations and those computed by using density functional theory. The second set is assigned to the corrin ring (14)N nuclei. The results identify the coenzyme's on-board dimethylbenzimidazole moiety as the alpha-axial ligand to cob(II)alamin in ethanolamine deaminase in the substrate radical-Co(II) biradical catalytic intermediate state. Thus, Co(II) is a pentacoordinate, alpha-axial liganded complex during turnover. We infer that dimethylbenzimidazole is also the alpha-axial ligand to the intact coenzyme in the resting enzyme. A 14% increase in the isotropic hyperfine coupling of the remote dimethylbenzimidazole (14)N nucleus in enzyme-bound versus free base-on cob(II)alamin shows an enhanced delocalization of unpaired spin density from Co(II) onto the axial ligand, which would contribute to the acceleration of the cobalt-carbon bond cleavage rate in situ.
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Affiliation(s)
- S C Ke
- Department of Physics, 1001 Rollins Research Center, 1510 Clifton Road, Emory University, Atlanta, Georgia 30322, USA
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Liu PY, Tung JC, Ke SC, Chen SL. Molecular epidemiology of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates in a district hospital in Taiwan. J Clin Microbiol 1998; 36:2759-62. [PMID: 9705432 PMCID: PMC105202 DOI: 10.1128/jcm.36.9.2759-2762.1998] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thirty-one of 104 clinical isolates of Klebsiella pneumoniae collected over a period of 8 months were found to be putative extended-spectrum beta-lactamase (ESBL) producers. Isoelectric focusing and an iodine overlay agar method were used for preliminary identification of the ESBLs. They were further identified by DNA sequencing. Seventy-one percent of the isolates were found to produce SHV-5. The variation in the ESBL patterns of these isolates was slight, with only five patterns being identified. The strains were typed by pulsed-field gel electrophoresis (PFGE), and 16 different genotypes were identified. When the PFGE patterns were analyzed by the algorithmic clustering method called the unweighted-pair group method using arithmetic averages, five clusters were found. However, significant genetic variations were found among 11 isolates and between each cluster. A plasmid of 36 kb was found in all clinical isolates and in the transconjugants. Our results indicate that the increase in the number of ESBL-producing K. pneumoniae isolates in this hospital is due mainly to the dissemination of a resistance plasmid rather than to the clonal spread of a few epidemic strains.
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Affiliation(s)
- P Y Liu
- Department of Internal Medicine, Shalu Tungs' Memorial Hospital, Shalu, Taiwan, Republic of China.
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Abstract
We and others have shown that fatty acids are important regulators of breast cancer cell proliferation. In particular individual fatty acids specifically alter EGF-induced cell proliferation in very different ways. This regulation is mediated by an EGFR/G-protein signaling pathway. Understanding the molecular mechanisms of how this signaling pathway functions and how fatty acids regulate it will provide important information on the cellular and molecular basis for the association of dietary fat and cancer. Furthermore these in vitro studies may explain data previously obtained from in vivo animal studies and identify "good" as well as "bad" fatty acids with respect to the development of cancer.
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Affiliation(s)
- R W Hardy
- Department of Pathology, University of Alabama at Birmingham, USA
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Abstract
Bacillus cereus is a well-known cause of food poisoning. It also causes rare systemic infections, usually in immunocompromised patients. Dissemination of this species in hospitals had been reported. Most of these episodes were pseudo-outbreaks and were usually secondary to equipment or environmental contamination. We report here on the use of pulsed-field gel electrophoresis (PFGE) to analyze a pseudo-outbreak of B. cereus in a pediatric unit. Different restriction endonucleases had been tested, and SmaI was found to give the best result for PFGE. Among the 26 clinical isolates of B. cereus and the type strain of the species, 15 distinct PFGE patterns were distinguished. PFGE after DNA macrorestriction with SmaI could clearly differentiate between the epidemiologically related isolates and the unrelated isolates. Because the same epidemic strain of B. cereus was isolated from the settle plates which were exposed near the outlet of the ventilation system, the source of this pseudo-outbreak was suspected to be the unit's air filtration system. This is one of the first reports of the application of PFGE to the study of B. cereus, and this method is useful for epidemiological investigation.
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Affiliation(s)
- P Y Liu
- Section of Infectious Diseases, Shalu Tungs' Memorial Hospital, Taiwan, Republic of China.
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Zhang S, Ke SC, Zvanut ME, Tohver HT, Vohra YK. Erratum: g tensor for substitutional nitrogen in diamond. Phys Rev B Condens Matter 1995; 51:8688. [PMID: 9986942 DOI: 10.1103/physrevb.51.8688.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ke SC, Tohver HT. Nitrogen-related defect in CaO. Phys Rev B Condens Matter 1994; 50:16060-16062. [PMID: 9975978 DOI: 10.1103/physrevb.50.16060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Zhang S, Ke SC, Zvanut ME, Tohver HT, Vohra YK. g tensor for substitutional nitrogen in diamond. Phys Rev B Condens Matter 1994; 49:15392-15395. [PMID: 10010663 DOI: 10.1103/physrevb.49.15392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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