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Zhang CL, Liu QZ, Wang J, Chu X, Shen LM, Guo YY. Epidemic and virulence characteristic of Shigella spp. with extended-spectrum cephalosporin resistance in Xiaoshan District, Hangzhou, China. BMC Infect Dis 2014; 14:260. [PMID: 24886028 PMCID: PMC4229937 DOI: 10.1186/1471-2334-14-260] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 05/08/2014] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Shigellae have become increasingly resistant to the extended-spectrum cephalosporin (ESC) worldwide and pose a great challenge to anti-infection treatment options. The purpose of this study was to determine the resistance, cephalosporin resistance mechanisms, virulence characteristic and genotype of ESC-resistant Shigella. METHODS From 2008 to 2012, Shigella isolates collected from diarrhea patients were detected for antibiotics sensitivity by disk diffusion, cephalosporin resistance determinants and virulence genes using polymerase chain reaction (PCR) and genotyping through enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR). RESULTS A total of 356 Shigella isolates were gathered, and 198 (55.6%, 58 S. flexneri and 140 S. sonnei) were resistant to ESC. All ESC-resistant isolates were susceptible to imipenem, and only 0.5% isolate was resistant to piperacillin/tazobactam. ESC-resistant S. flexneri showed high degrees of resistance to ampicillin (100%), ampicillin/sulbactam (96.6%), piperacillin (100%), trimethoprim/sulfamethoxazole (74.1%), ciprofloxacin (74.1%), levofloxacin (53.4%), ceftazidime (58.6%) and cefepime (58.6%). ESC-resistant S. sonnei exhibited high resistance rates to ampicillin (100%), piperacillin (100%) and trimethoprim/sulfamethoxazole (96.4%). Cephalosporin resistance genes were confirmed in 184 ESC-resistant isolates. bla(CTX-M) types (91.8%, mainly bla(CTX-M-14), bla(CTX-M-15) and bla(CTX-M-57)) were most prevalent, followed by bla(OXA-30) (26.3%). Over 99.0% ESC-resistant isolates harbored virulence genes ial, ipaH, virA and sen. However, set1 were more prevalent in ESC-resistant S. flexneri isolates than in S. sonnei isolates. ERIC-PCR results showed that 2 and 3 main genotypes were detected in ESC-resistant S. flexneri and S. sonnei, respectively. CONCLUSION Our findings indicated that a high prevalence of ESC-resistant Shigella mediated mainly by bla(CTX-M) with stronger resistance and virulence, and the existence of specific clones responsible for these Shigella infection in the region studied.
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Affiliation(s)
| | - Qing-Zhong Liu
- Department of Clinical Laboratory, Shanghai First People's Hospital, School of Medicine, Shanghai Jiaotong University, 100 Haining Road, Shanghai 200080, People's Republic of China.
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Martins HSI, Bomfim MRQ, França RO, Farias LM, Carvalho MAR, Serufo JC, Santos SG. Resistance markers and genetic diversity in Acinetobacter baumannii strains recovered from nosocomial bloodstream infections. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2014; 11:1465-78. [PMID: 24477210 PMCID: PMC3945548 DOI: 10.3390/ijerph110201465] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 01/09/2014] [Accepted: 01/18/2014] [Indexed: 01/25/2023]
Abstract
In this study, phenotypic and genotypic methods were used to detect metallo-β-lactamases, cephalosporinases and oxacillinases and to assess genetic diversity among 64 multiresistant Acinetobacter baumannii strains recovered from blood cultures in five different hospitals in Brazil from December 2008 to June 2009. High rates of resistance to imipenem (93.75%) and polymyxin B (39.06%) were observed using the disk diffusion (DD) method and by determining the minimum inhibitory concentration (MIC). Using the disk approximation method, thirty-nine strains (60.9%) were phenotypically positive for class D enzymes, and 51 strains (79.6%) were positive for cephalosporinase (AmpC). Using the E-test, 60 strains (93.75%) were positive for metallo-β-lactamases (MβLs). All strains were positive for at least one of the 10 studied genes; 59 (92.1%) contained blaVIM-1, 79.6% contained blaAmpC, 93.7% contained blaOXA23 and 84.3% contained blaOXA51. Enterobacteria Repetitive Intergenic Consensus (ERIC)-PCR analysis revealed a predominance of certain clones that differed from each other. However, the same band pattern was observed in samples from the different hospitals studied, demonstrating correlation between the genotypic and phenotypic results. Thus, ERIC-PCR is an appropriate method for rapidly clustering genetically related isolates. These results suggest that defined clonal clusters are circulating within the studied hospitals. These results also show that the prevalence of MDR A. baumannii may vary among clones disseminated in specific hospitals, and they emphasize the importance of adhering to appropriate infection control measures.
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Affiliation(s)
- Hanoch S I Martins
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
| | - Maria Rosa Q Bomfim
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
| | - Rafaela O França
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
| | - Luiz M Farias
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
| | - Maria Auxiliadora R Carvalho
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
| | - José Carlos Serufo
- Departamento de Clínica Médica, Faculdade de Medicina, Universidade Federal de Minas Gerais, Professor Alfredo Balena 190, Santa Efigênia 30130-100, Belo Horizonte, MG, Brazil.
| | - Simone G Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Antônio Carlos 6627, Pampulha 31207-901, Belo Horizonte, Minas Gerais, Brazil.
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John S, Ramasamy B. Bioprospecting of marine Streptomycetes sp. for its antagonistic activity on MDR Pseudomonas aeruginosa and Acinetobacter baumannii isolates. ASIAN PACIFIC JOURNAL OF TROPICAL DISEASE 2014. [DOI: 10.1016/s2222-1808(14)60458-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Zhang X, Lou D, Xu Y, Shang Y, Li D, Huang X, Li Y, Hu L, Wang L, Yu F. First identification of coexistence of blaNDM-1 and blaCMY-42 among Escherichia coli ST167 clinical isolates. BMC Microbiol 2013; 13:282. [PMID: 24313961 PMCID: PMC4029178 DOI: 10.1186/1471-2180-13-282] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 11/28/2013] [Indexed: 11/14/2022] Open
Abstract
Background Emergence of multidrug resistance in Enterobacteriaceae limits the selection of antimicrobials for treatment of infectious diseases. Identification of NDM-1 makes more difficulty in treating multidrug-resistant Enterobacteriaceae infections. Carbapenem-resistant Escherichia coli clinical isolates from a tertiary hospital in Wenzhou, east China, were investigated for NDM-1 production. Results The two tested isolates were negative for modified Hodge test, but positive for a double-disc synergy test used for detecting metallo-β-lactamase production. E. coli WZ33 and WZ51 exhibited discrepant-level resistance to most clinically frequent used antimicrobials, but still susceptible to trimethoprim/sulfamethoxazole, amikacin, fosfomycin, tigecycline and polymyxin B. E. coli WZ33 and WZ51 were positive for blaNDM-1 determined by PCR and DNA sequencing. Other than blaNDM-1, E. coli WZ33 also harbored blaCTX-M-14 and blaCMY-42, while E. coli WZ51 simultaneously harbored blaSHV-12,blaCTX-M-14 and blaCMY-42. Carbapenem resistance for E. coli WZ51 and WZ33 could not be transferred to E. coli recipients through conjugation, but could be transferred to E. coli recipients by chemical transformation. The EcoR1-digested DNA pattern of plasmids from the transformant of E. coli WZ51 was different from that of E. coli WZ51. MLST showed that E. coli WZ33 and WZ51 belonged to an animal-associated clone (ST167). Conclusion The present study is the first report of blaNDM-1 carriage in E. coli ST167 isolates and coexistence of blaNDM-1 and blaCMY-42 in same isolate. Systemic surveillance should focus on the dissemination of blaNDM-1 among Enterobacteriaceae, especially E. coli ST167 clone associated with animal infection.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Liangxing Wang
- Department of Laboratory Medicine, The First Affiliated Hospital of Wenzhou Medical University, 2 Fuxue lane, Wenzhou 325000, China.
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Lee CH, Lee YT, Kung CH, Ku WW, Kuo SC, Chen TL, Fung CP. Risk factors of community-onset urinary tract infections caused by plasmid-mediated AmpC β-lactamase-producing Enterobacteriaceae. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2013; 48:269-75. [PMID: 24239065 DOI: 10.1016/j.jmii.2013.08.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 08/01/2013] [Accepted: 08/20/2013] [Indexed: 11/19/2022]
Abstract
BACKGROUND The AmpC β-lactamase (AmpC)-producing Enterobacteriaceae emerged worldwide. This study was conducted to determine the risk factors of community-onset urinary tract infections (UTIs) caused by plasmid-mediated AmpC-producing Enterobacteriaceae. METHODS Patients who were diagnosed as community-onset UTIs caused by Enterobacteriaceae in a tertiary-care teaching hospital from December 2010 to January 2012 were included. Extended-spectrum β-lactamase (ESBL)-producing isolates were excluded. We identified plasmid-mediated AmpC-producing Enterobacteriaceae both phenotypically (by disk potentiation test and double-disk synergy test) and genotypically (by Multiplex polymerase chain reaction (PCR) assay). The demographic data, clinical characteristics, and risk factors of acquisition were described. RESULTS Among the 323 non-ESBL-producing Enterobacteriaceae identified in community-onset UTIs, 50 isolates were phenotypically positive for AmpC. Escherichia coli was the most common AmpC-producing organism (60%), followed by Klebsiella pneumonia (8%), and Enterobacter cloacae and Proteus mirabilis (6% for each species). The independent risk factors for acquisition of AmpC-producing Enterobacteriaceae included prior history of cerebral vascular accident [odds ratio (OR) = 2.014; 95% confidence interval (CI) = 1.007-4.031; p = 0.0048], and prior use of fluoroquinolones (OR = 4.049; 95% CI = 1.759-9.319; p = 0.001) and cephamycin (OR = 9.683; 95% CI = 2.007-45.135; p = 0.004). AmpC-producing isolates were multidrug resistant. Carbapenems, cefepime, and piperacillin/tazobactam had the best in vitro efficacy. The most commonly identified plasmid-mediated AmpC gene was bla(CIT), followed by bla(DHA)/bla(EBC), and bla(MOx). CONCLUSION For community-onset UTIs, AmpC-producing Enterobacteriaceae should be suspected in those with prior history of cerebral vascular accident and prior use of antimicrobials. To treat these multiple-resistant isolates, carbapenems, cefepime, and piperacillin/tazobactam may be considered.
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Affiliation(s)
- Chi-Hung Lee
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan
| | - Yi-Tzu Lee
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan; Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Che-Hsuan Kung
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Internal Medicine, Taipei City Hospital, Zhongxing Branch, Taipei, Taiwan
| | - Wen-Wei Ku
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Shu-Chen Kuo
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan.
| | - Te-Li Chen
- Institute of Clinical Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan
| | - Chang-Phone Fung
- Division of Infectious Diseases, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan
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Campana EH, Barbosa PP, Fehlberg LCC, Gales AC. Frequency of plasmid-mediated AmpC in Enterobacteriaceae isolated in a Brazilian Teaching Hospital. Braz J Microbiol 2013; 44:477-80. [PMID: 24294242 PMCID: PMC3833148 DOI: 10.1590/s1517-83822013000200023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 06/05/2012] [Indexed: 11/22/2022] Open
Abstract
In Brazil, the presence of plasmid-mediated AmpC (pAmpC)-producing isolates has been sporadically reported. We evaluated the frequency of pAmpC among 133 Enterobacteriaceae clinical isolates. The blaCMY-2-like gene was detected in a single Klebsiella pneumoniae isolate. In our study, the pAmpC frequency was very low as previously reported.
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Affiliation(s)
- Eloiza H Campana
- Laboratório ALERTA, Disciplina de Infectologia, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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Yilmaz NO, Agus N, Bozcal E, Oner O, Uzel A. Detection of plasmid-mediated AmpC β-lactamase in Escherichia coli and Klebsiella pneumoniae. Indian J Med Microbiol 2013; 31:53-9. [PMID: 23508430 DOI: 10.4103/0255-0857.108723] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Detecting plasmid-mediated AmpC (pAmpC) β-lactamase-producing organism is important for optimal infection control and providing accurate and effective treatment option for physicians. OBJECTIVES The aim of this study was to investigate the prevalence of pAmpC β-lactamase and compare the results of boronic acid (BA) disk test with other phenotypic tests detecting AmpC positive isolates. MATERIALS AND METHODS A total of 273 clinical isolates of Klebsiella pneumoniae (n: 82) and Escherichia coli (n: 191) were analysed. The presence of pAmpC β-lactamase was determined by BA disk test, cefoxitin (FOX) screening test, modified three dimensional test (M3DT), and multiplex polymerase chain reaction (PCR). Pulsed-field gel electrophoresis was performed to evaluate the genetic similarities between isolates. To detect extended spectrum β-lactamases (ESBL) in the presence of AmpC β-lactamase, ESBL confirmation test was carried out with and without BA solution. RESULTS Of the 273 strains tested, 127 strains were found FOX resistant, 114 were positive by M3DT, 108 were positive in BA disk test, and the multiplex PCR detected 24 pAmpC β-lactamase-positive isolate. The prevalence of AmpC-producing strains was 10.9% in E. coli and 3.6% in K. pneumoniae in the tested population by PCR. CIT and MOX group genes were predominant type in these strains. CONCLUSION These results emphasize that clinical laboratories should consider testing the presence of pAmpC enzymes particularly in FOX-resistant isolates, and BA disk test will improve detection of this emerging resistance phenotype.
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Affiliation(s)
- N O Yilmaz
- Department of Microbiology Laboratory, Tepecik Educational and Research Hospital, Ege University, Izmir, Turkey
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Luk S, Wong WK, Ng TK, To WK, Lo TH. Detection of plasmid-mediated AmpC β-lactamases in isolates of Klebsiella pneumoniae in a regional laboratory in Hong Kong, China. Diagn Microbiol Infect Dis 2013; 76:252-3. [DOI: 10.1016/j.diagmicrobio.2013.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 12/21/2012] [Accepted: 02/11/2013] [Indexed: 10/27/2022]
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Thakuria B, Lahon K. The Beta Lactam Antibiotics as an Empirical Therapy in a Developing Country: An Update on Their Current Status and Recommendations to Counter the Resistance against Them. J Clin Diagn Res 2013; 7:1207-14. [PMID: 23905143 DOI: 10.7860/jcdr/2013/5239.3052] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 04/09/2013] [Indexed: 11/24/2022]
Abstract
In a developing country like India, where the patients have to bear the cost of their healthcare, the microbiological culture and the sensitivity testing of each and every infection is not feasible. Moreover, there are lacunae in the data storage, management and the sharing of knowledge with respect to the microorganisms which are prevalent in the local geographical area and with respect to the antibiotics which are effective against them. Thus, an empirical therapy for treating infections is imperative in such a setting. The beta lactam antibiotics have been widely used for the empirical treatment of infections since the the discovery of penicillin. Many generations of beta lactams have been launched with, the claims of a higher sensitivity and less resistance, but their sensitivity has drastically decreased over time. Thus, the preference for beta lactams, especially the cephalosporins, as an empirical therapy, among the prescribers was justified initially, but the current sensitivity patterns do not support their empirical use in hospital and community acquired infections. There is a need for increasing the awareness and the attitudinal change among the prescribers, screening of the antibiotic prescriptions, the strict implementation of antibiotic policies in hospital settings, restricting the hospital supplies and avoiding the prescriptions of beta lactams, a regular census of the local sensitivity patterns to formulate and update the antibiotic policies, upgradation of the laboratory facilities for a better and faster detection of the isolates, proper collection, analyses and sharing of the data and the encouragement of the research and development of newer antibiotics with novel mechanisms of action.
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Affiliation(s)
- Bhaskar Thakuria
- Associate Professor, Department of Microbiology, Subharti Medical College , Meerut, Uttar Pradesh-250005, India
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Mishra S, Sen MR, Upadhyay S, Bhattacharjee A. Genetic linkage of blaNDM among nosocomial isolates of Acinetobacter baumannii from a tertiary referral hospital in northern India. Int J Antimicrob Agents 2013; 41:452-6. [DOI: 10.1016/j.ijantimicag.2013.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/29/2012] [Accepted: 01/03/2013] [Indexed: 11/30/2022]
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First report of a nonmetallocarbapenemase class A carbapenemase in an Enterobacter cloacae isolate from Colombia. Antimicrob Agents Chemother 2013; 57:3457. [PMID: 23612204 DOI: 10.1128/aac.02425-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Bakthavatchalu S, Shakthivel U, Mishra T. Detection of ESBL among AmpC producing enterobacteriaceae using inhibitor-based method. Pan Afr Med J 2013; 14:28. [PMID: 23504148 PMCID: PMC3597859 DOI: 10.11604/pamj.2013.14.28.1347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 01/03/2013] [Indexed: 11/17/2022] Open
Abstract
Introduction The occurrence of multiple β-lactamases among bacteria only limits the therapeutic options but also poses a challenge. A study using boronic acid (BA), an AmpC enzyme inhibitor, was designed to detect the combined expression of AmpC β-lactamases and extended-spectrum β-lactamases (ESBLs) in bacterial isolates further different phenotypic methods are compared to detect ESBL and AmpC. Methods A total of 259 clinical isolates of Enterobacteriaceae were isolated and screened for ESBL production by (i) CLSI double-disk diffusion method (ii) cefepime- clavulanic acid method (iii) boronic disk potentiation method. AmpC production was detected using cefoxitin alone and in combination with boronic acid and confirmation was done by three dimensional disk methods. Isolates were also subjected to detailed antibiotic susceptibility test. Results Among 259 isolates, 20.46% were coproducers of ESBL and AmpC, 26.45% were ESBL and 5.40% were AmpC. All of the 53 AmpC and ESBL coproducers were accurately detected by boronic acid disk potentiation method. Conclusion The BA disk test using Clinical and Laboratory Standards Institute methodology is simple and very efficient method that accurately detects the isolates that harbor both AmpCs and ESBLs.
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Affiliation(s)
- Sasirekha Bakthavatchalu
- Department of Microbiology, Centre for Post Graduate Studies, Jain University, Bangalore, Karnataka--560 011, India
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Prevalence of AmpC and SHV β-Lactamases in Clinical Isolates of Escherichia coli From Tehran Hospitals. Jundishapur J Microbiol 2013. [DOI: 10.5812/jjm.5043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Shanthi J, Pazhanimurugan R, Gopikrishnan V, Balagurunathan R. Mechanism of drug resistance, characterization of plasmid-borne determinants and transformation study in P. aeruginosa from burn and ICU units-its susceptibility pattern. Burns 2012; 39:643-9. [PMID: 22980776 DOI: 10.1016/j.burns.2012.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 08/09/2012] [Accepted: 08/14/2012] [Indexed: 11/28/2022]
Abstract
The transfer of drug resistance between hospital pathogens has led to alarming increase of multidrug resistant strains imposing therapeutic challenges. These resistant isolates harbor various mechanisms to counteract the drugs administered and have been reported to deliver these factors to sensitive strains in hostile environment. The present study aimed to screen for multidrug resistant Pseudomonas aeruginosa strains for the production of extended-spectrum β-lactamases, metallo-β-lactamases, AmpC β-lactamase, drug efflux phenotypes and co-transfer the resistance for cephalosporin and other non-beta lactam antibiotics in CaCl2 treated drug sensitive E. coli strains. From the 87 samples processed about 23 isolates of P. aeruginosa were ESBL and MBL positive, 5 (20%) were found to be AmpC β-lactamase producers, efflux mechanism was observed in 8 isolates, 15 isolates had MIC of 16 μg/ml. A putative efflux mechanism was observed in 8 out of 23 isolates that showed decrease in the MIC of meropenem with reserpine. The plasmid profile was characterized for all the common isolates obtained from burn and ICU units. About 69.66% of E. coli recombinants scored positive for both beta lactam and non-beta lactam antibiotics is due to co transfer of resistant plasmid obtained from P. aeruginosa.
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Affiliation(s)
- J Shanthi
- Bharathiar University, Coimbatore 641046, Tamil Nadu, India
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Development of a TaqMan multiplex PCR assay for detection of plasmid-mediated ampC β-lactamase genes. J Clin Microbiol 2012; 50:3722-5. [PMID: 22895035 DOI: 10.1128/jcm.02038-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A multiplex, real-time TaqMan assay was designed to identify clinical isolates carrying plasmid-mediated ampC genes. The specificity and sensitivity of this assay were 100% when testing characterized AmpC/non-AmpC-producing isolates and randomly selected clinical isolates. This is a rapid assay that can be performed in a clinical microbiology laboratory.
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Gupta V, Kumarasamy K, Gulati N, Garg R, Krishnan P, Chander J. AmpC β-lactamases in nosocomial isolates of Klebsiella pneumoniae from India. Indian J Med Res 2012; 136:237-41. [PMID: 22960890 PMCID: PMC3461735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND & OBJECTIVES AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. METHODS One hundred consecutive, non-duplicate clinical isolates of K. pneumoniae collected over a period of one year (June 2008 - June 2009) were included in the study. An antibiotic susceptibility method was used with 10 antibiotics for Gram-negative infections which helped in screening for ESBL and AmpC β-lactamases and also in confirmation of ESBL production. The detection of AmpC β-lactamases was done based on screening and confirmatory tests. For screening, disc diffusion zones of cefoxitin <18 mm was taken as cefoxitin resistant. All cefoxitin resistant isolates were tested further by AmpC disk test and modified three dimensional test. Multiplex-PCR was performed for screening the presence of plasmid-mediated AmpC genes. RESULTS Of the 100 isolates of K. pneumoniae studied, 48 were resistant to cefoxitin on screening. AmpC disk test was positive in 32 (32%) isolates. This was also confirmed with modified three dimensional test. Indentation indicating strong AmpC producer was observed in 25 isolates whereas little distortion (weak AmpC) was observed in 7 isolates. ESBL detection was confirmed by a modification of double disk synergy test in 56 isolates. Cefepime was the best cephalosporin in synergy with tazobactam for detecting ESBL production in isolates co-producing AmpC β-lactamases. The subsets of isolates phenotypically AmpC β-lactamase positive were subjected to amplification of six different families of AmpC gene using multiplex PCR. The sequence analysis revealed 12 CMY-2 and eight DHA-1 types. INTERPRETATION & CONCLUSIONS Tazobactam was the best β-lactamase inhibitor for detecting ESBL in presence of AmpC β-lactamase as this is a very poor inducer of AmpC gene. Amongst cephalosporins, cefepime was the best cephalosporin in detecting ESBL in presence of AmpC β-lactamase as it is least hydrolyzed by AmpC enzymes. Cefepime-tazobactam combination disk test would be a simple and best method in detection of ESBLs in Enterobacteriaceae co-producing AmpC β-lactamase in the routine diagnostic microbiology laboratories.
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Affiliation(s)
- Varsha Gupta
- Department of Microbiology, Government Medical College & Hospital, Chandigarh, India,Reprint requests: Dr Varsha Gupta, Professor, Department of Microbiology, Government Medical College & Hospital, Sector-32, Chandigarh 160 030, India e-mail:
| | | | - Neelam Gulati
- Department of Microbiology, Government Medical College & Hospital, Chandigarh, India
| | - Ritu Garg
- Department of Microbiology, Government Medical College & Hospital, Chandigarh, India
| | - Padma Krishnan
- Department of Microbiology, Dr ALM PG IBMS, University of Madras, Chennai, India
| | - Jagdish Chander
- Department of Microbiology, Government Medical College & Hospital, Chandigarh, India
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Lee CC, Lui G, Ip M, Ling TKW, Lee N. Frequent detection of plasmid-mediated quinolone resistance (qnr) genes in multidrug-resistant Enterobacteriaceae blood isolates, Hong Kong. Eur J Clin Microbiol Infect Dis 2012; 31:3183-9. [PMID: 22744730 DOI: 10.1007/s10096-012-1683-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 06/12/2012] [Indexed: 11/28/2022]
Abstract
Plasmid-mediated quinolone resistance (qnr) genes confer low-level resistance but provide background for selection of highly-resistant strains. We investigated their prevalence and significance in clinical Enterobacteriaceae bacteremic isolates in Hong Kong. A prospective, hospital-based study was conducted (January 2008 to March 2009). Consecutive, non-duplicate blood isolates of extended-spectrum-β-lactamase (ESBL) and/or plasmid-mediated AmpC (PMAmpC) β-lactamase-producing Enterobacteriaceae were collected and subjected to qnr genes detection using multiplex PCR. Direct sequencing was performed to characterize the qnr and the co-existing bla genes. Clinical and microbiological variables, including antimicrobial resistance profiles, were compared between infections by 'qnr-positive' and 'qnr-negative' Enterobacteriaceae. Altogether 199 ESBL/PMAmpC-producing Enterobacteriaceae isolates were studied. qnr genes were detected in 20 % (qnrB, n = 24; qnrS, n = 16; qnrA, n = 0), of which 85% were Klebsiella spp. There was a strong association with PMAmpC genes (qnrB and DHA-1; p < 0.001). 'qnr-positive' isolates were more commonly hospital-acquired (60.0% vs 35.8%; adjusted OR 2.68, 95%CI 1.32-5.46) and multidrug-resistant (e.g. amoxicillin-clavulanate 90-100%, piperacillin-tazobactam 40-57%, ceftazidime 53-78%; sulfamethoxazole/trimethoprim 60-70%; ciprofloxacin 53-65%, levofloxacin 35-48%). Patients with 'qnr-positive' Enterobacteriaceae bacteremia had a higher 30-day mortality (45% vs 22%, p = 0.003). High Pitt bacteremia score, development of pneumonia, and failure to receive susceptible fluoroquinolone (adjusted HR 4.27; 95%CI 1.45-12.61) or carbapenem (adjusted HR 3.04; 95%CI 1.49-6.20) treatment were independent factors associated with death. A high proportion of ESBL/PMAmpC-producing Enterobacteriaceae (typically Klebsiella) bacteremic isolates carried qnr. These strains were multidrug-resistant, which was associated with inappropriate treatment and high fatality. Further dissemination of qnr and selection of fluoroquinolone/β-lactam-resistant strains should be closely monitored and controlled.
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Affiliation(s)
- C C Lee
- Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, 9/F, Clinical Sciences Building, Shatin, Hong Kong SAR, China
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Mohamudha PR, Harish BN, Parija SC. Molecular description of plasmid-mediated AmpC β-lactamases among nosocomial isolates of Escherichia coli & Klebsiella pneumoniae from six different hospitals in India. Indian J Med Res 2012; 135:114-9. [PMID: 22382192 PMCID: PMC3307170 DOI: 10.4103/0971-5916.93433] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND & OBJECTIVES Plasmid mediated AmpC β-lactamase (PMABL) resistance in Escherichia coli and Klebsiella spp. is an emerging problem worldwide. Phenotypic methods are commonly used for detection of PMABL production in Gram-negative isolates, but molecular data about the prevalence of plasmid-mediated AmpC-type resistance at the national level are needed. Hence, a prospective study was undertaken to determine the occurrence of PMABL gene and its types among clinical isolates of E. coli and K. pneumoniae obtained from six different hospitals in India. METHODS A total of 241 nosocomial isolates of K. pneumoniae (n=109) and E.coli (n=132) from six geographically distant hospitals in India were included. These were screened for cefoxitin resistance. AmpC disk test and modified three dimensional extraction test were used for phenotypic detection of PMABL production. Molecular types were determined by a multiplex PCR. RESULTS Among the 241 isolates, 187 (77.5%) were found to be cefoxitin resistant (K. pneumoniae n=83, E. coli n=104). AmpC activity was detectable in 153 (63.4%) isolates, (K. pneumoniae n=69, E. coli n=84). By PCR, the plasmid encoded AmpC genes were found in 92 (38.1%) isolates and the molecular types of the genes detected predominantly were DHA, CIT followed by MOX and ACC types. INTERPRETATION & CONCLUSIONS A high percentage of plasmid-encoded AmpC enzymes was noted in E. coli and K. pneumonia isolates obtained from different parts of the country. Phenotypic methods alone may not reflect the true number of PMABL producers. Genotypic methods need to be employed in national surveillance studies.
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Affiliation(s)
- Parveen R Mohamudha
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education & Research, Puducherry, India
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Zhou XZ, Jia F, Liu XM, Yang C, Zhao L, Wang YJ. Total alkaloids from Sophora alopecuroides L. increase susceptibility of extended-spectrum β-lactamases producing Escherichia coli isolates to cefotaxime and ceftazidime. Chin J Integr Med 2012; 19:945-52. [PMID: 22528755 DOI: 10.1007/s11655-011-0899-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Indexed: 01/20/2023]
Abstract
OBJECTIVE To evaluate the antimicrobial activity of total alkaloids extracted from Sophorea alopecuroides L. (TASA) against clinical isolated extended-spectrum beta-lactamases (ESBLs) producing Escherichia coli (E. coli) strains. METHODS The antibacterial activity of TASA either itself or in combination with cefotaxime (CTX) or ceftazidime (CAZ) was investigated by using the microbroth dilution method and phenotypic confirmatory disk diffusion test against three clinical isolated ESBLs-producing E. coli strains; the interactions of TASA and CTX or CAZ were ascertained by evaluating the fractional inhibitory concentration index (FICI). RESULTS The antibacterial activity of either TASA itself or in combination with CTX or CAZ was found. The minimum inhibitory concentration (MICs) of TASA against the ESBLs producing isolates was 12.5 mg/mL. In the combinations with a sub-inhibitory concentration of TASA, a synergistic effect on CTX and CAZ against the ESBLs producing isolates was observed. Similarly, the isolates exposed to lower dose of TASA yielded an increased susceptibility to CTX and CAZ by 8-16 folds determined by microdilution assay. Moreover, enzymatic detection of ESBLs demonstrated that TASA induced reversal resistance to CTX and CAZ partially by a mechanism of inhibition of ESBLs activity in these isolates. Additionally, in the tested isolates following the exposure of TASA, molecular analysis verified the SHV-type beta-lactamase encoding ESBL gene in these isolates, and no mutation was introduced into the ESBL gene. CONCLUSIONS These results suggest that TASA could be used as a source of natural compound with pharmacological activity of reversal resistance to antimicrobial agent. These findings also indicated that the application of the TASA in combination with antibiotics might prove useful in the control and treatment of infectious diseases caused by the ESBLs producing enterobacteriaceae.
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Affiliation(s)
- Xue-zhang Zhou
- Key Laboratory of the Ministry of Education for the Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, 750021, China
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Jenkins SG, Schuetz AN. Current concepts in laboratory testing to guide antimicrobial therapy. Mayo Clin Proc 2012; 87:290-308. [PMID: 22386185 PMCID: PMC3496983 DOI: 10.1016/j.mayocp.2012.01.007] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 01/17/2012] [Accepted: 01/23/2012] [Indexed: 02/08/2023]
Abstract
Antimicrobial susceptibility testing (AST) is indicated for pathogens contributing to an infectious process that warrants antimicrobial therapy if susceptibility to antimicrobials cannot be predicted reliably based on knowledge of their identity. Such tests are most frequently used when the etiologic agents are members of species capable of demonstrating resistance to commonly prescribed antibiotics. Some organisms have predictable susceptibility to antimicrobial agents (ie, Streptococcus pyogenes to penicillin), and empirical therapy for these organisms is typically used. Therefore, AST for such pathogens is seldom required or performed. In addition, AST is valuable in evaluating the activity of new and experimental compounds and investigating the epidemiology of antimicrobial resistant pathogens. Several laboratory methods are available to characterize the in vitro susceptibility of bacteria to antimicrobial agents. When the nature of the infection is unclear and the culture yields mixed growth or usual microbiota (wherein the isolates usually bear little relationship to the actual infectious process), AST is usually unnecessary and results may, in fact, be dangerously misleading. Phenotypic methods for detection of specific antimicrobial resistance mechanisms are increasingly being used to complement AST (ie, inducible clindamycin resistance among several gram-positive bacteria) and to provide clinicians with preliminary direction for antibiotic selection pending results generated from standardized AST (ie, β-lactamase tests). In addition, molecular methods are being developed and incorporated by microbiology laboratories into resistance detection algorithms for rapid, sensitive assessment of carriage states of epidemiologically and clinically important pathogens, often directly from clinical specimens (ie, presence of vancomycin-resistant enterococci in fecal specimens).
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Affiliation(s)
- Stephen G Jenkins
- Department of Pathology, Weill Cornell Medical College, East 68th Street, New York, NY 10065, USA.
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71
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Evaluation of four phenotypic methods to detect plasmid-mediated AmpC β-lactamases in clinical isolates. Eur J Clin Microbiol Infect Dis 2012; 31:2037-43. [PMID: 22278294 DOI: 10.1007/s10096-011-1537-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 12/21/2011] [Indexed: 10/14/2022]
Abstract
Four phenotypic methods (three dimensional test, AmpC test, cloxacillin synergy test and cefotetan/cefotetan-cloxacillin E-test) to detect plasmid-mediated AmpC β-lactamases (pAmpC) were compared in 125 clinical Enterobacteriaceae isolates with AmpC profile: 74 E. coli (bla (CMY-2): 70; bla (DHA-1): 4), five K. pneumoniae (bla (CMY-2): 2; bla (DHA-1): 3), six P. mirabilis (bla (CMY-2): 6) and 40 negative isolates for pAmpC β-lactamases. All evaluated methods showed a good sensitivity (>95%) but low values of specificity (<60%) in E. coli, explained by an increase of AmpC expression caused by chromosomal ampC promoter/attenuator mutations (-42, -18, -1, +58, predominantly). The cefotetan/cefotetan-cloxacillin or cloxacillin synergy test may be advocated as phenotypic screening test, and the AmpC test as confirmatory test for detection of pAmpC in isolates that lack or minimally express chromosomally encoded AmpC β-lactamases. In the case of E. coli, the phenotypic evaluated tests were not able to differentiate between chromosomal ampC overexpression or acquisition of plasmid-encoded ampC genes.
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Li GL, Duo LB, Luan Y, Wang CY, Wang WP, Zhang HG, Sun Q, Qi GY. Identification of genotypes of plasmid-encoded AmpC beta-lactamases from clinical isolates and characterization of mutations in their promoter and attenuator regions. Gene Expr 2012; 15:215-23. [PMID: 23539899 PMCID: PMC6043836 DOI: 10.3727/105221613x13571653093204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We investigated the occurrence of AmpC beta-lactamases among Escherichia coli and Klebsiella pneumoniae isolates and determined the genotype of plasmid-mediated AmpC beta-lactamases at a medical center. The AmpC beta-lactamase promoter and attenuator were amplified from chromosomal DNA of high AmpC-producing E. coli isolates and sequenced. Antibiotic screening and 3D extract tests showed the presence of AmpC beta-lactamase in 3.56% of K. pneumoniae and 1.88% of E. coli isolates. Ten isolates (six K. pneumoniae and four E. coli) were positive for extended spectrum beta-lactamase (ESBL) as indicated by the double disc diffusion method. DHA-1 plasmid-encoded AmpC beta-lactamase was present in 10 K. pneumoniae isolates and four E.coli isolates. E. coli chromosomal AmpC beta-lactamase carried polymorphisms in the -42, -32, and -18 bases of the promoter and in the +26 and +27 bases of the attenuator, which may play a role in antibiotic resistance. The observed mutations may have clinical implications for the management of antibiotic-resistant infections.
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Affiliation(s)
- Gui-Ling Li
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Li-Bo Duo
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Ying Luan
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Cheng-Ying Wang
- †Medicine Laboratory, Department of Urology Surgery, DaQing Oilfield General Hospital, DaQing, Heilongjiang, China
| | - Wei-Ping Wang
- †Medicine Laboratory, Department of Urology Surgery, DaQing Oilfield General Hospital, DaQing, Heilongjiang, China
| | - He-Guang Zhang
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Qi Sun
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
| | - Gui-Yun Qi
- *Department of Medicine Laboratory, Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang, China
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73
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Shoorashetty RM, Nagarathnamma T, Prathibha J. Comparison of the boronic acid disk potentiation test and cefepime-clavulanic acid method for the detection of ESBL among AmpC-producing Enterobacteriaceae. Indian J Med Microbiol 2011; 29:297-301. [PMID: 21860114 DOI: 10.4103/0255-0857.83917] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
PURPOSE Extended spectrum β-lactamase (ESBL) and AmpC β-lactamase are important mechanisms of betalactam resistance among Enterobacteriaceae . The ESBL confirmation test described by Clinical Laboratory Standards Institute (CLSI) is in routine use. This method fails to detect ESBL in the presence of AmpC. Therefore, we compared two different ESBL detection methods against the CLSI confirmatory test. MATERIALS AND METHODS A total 200 consecutive clinical isolates of Enterobacteriaceae from various clinical samples were tested for ESBL production using (i) CLSI described phenotypic confirmatory test (PCT), (ii) boronic acid disk potentiation test and (iii) cefepime-CA disk potentiation method. AmpC confirmation was done by a modified three-dimensional test. RESULTS Among total 200 Enterobacteriaceae isolates, 82 were only ESBL producers, 12 were only AmpC producers, 55 were combined ESBL and AmpC producers, 14 were inducible AmpC producers and 37 isolates did not harboured any enzymes. The CLSI described PCT detected ESBL-producing organisms correctly but failed to detect 36.3% of ESBLs among combined enzyme producers. The boronic acid disk potentiation test reliably detected all ESBL, AmpC, and combined enzyme producers correctly. The cefepime-CA method detected all ESBLs correctly but another method of AmpC detection has to be adopted. CONCLUSION The use of boronic acid in disk diffusion testing along with the CLSI described PCT enhances ESBL detection in the presence of AmpC betalactamases.
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Affiliation(s)
- R M Shoorashetty
- Department of Microbiology, Pondicherry Institute of Medical Sciences, Ganapathichettikulam, Kalapet, Pondicherry, India
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74
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Yu F, Chen C, Chen Q, Yu X, Ding B, Yang L, Li Q, Qin Z, Parsons C, Zhang X, Zhang L, Qu D, Wang L, Pan J. Identification of transferable DHA-1 type AmpC β-lactamases and two mutations in quinolone resistance-determining regions of Salmonella enterica serovar Thompson. J Med Microbiol 2011; 61:460-462. [PMID: 22096136 DOI: 10.1099/jmm.0.040691-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Fangyou Yu
- Department of Laboratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Chun Chen
- Department of Respiratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Qiang Chen
- Department of Laboratory Medicine, Jiangxi Provincial Children Hospital, Nanchang 336000, PR China
| | - Xiaojun Yu
- Department of Laboratory Medicine, Jiangxi Provincial Children Hospital, Nanchang 336000, PR China
| | - Baixing Ding
- Department of Intensive Care Unit, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Lehe Yang
- Department of Respiratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Qiaoqiao Li
- Department of Respiratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Zhiqiang Qin
- Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Chris Parsons
- Division of Infectious Diseases, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Xueqing Zhang
- Department of Laboratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Liming Zhang
- Department of Laboratory Medicine, Taizhou Center Hospital, Taizhou 318000, PR China
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of the Ministries of Education and Health, Institute of Medical Microbiology and Institute of Biomedical Sciences, Shanghai Medical School, Fudan University, Shanghai 200032, PR China
| | - Liangxing Wang
- Department of Respiratory Medicine, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
| | - Jingye Pan
- Department of Intensive Care Unit, First Affiliated Hospital of Wenzhou Medical College, Wenzhou 325000, PR China
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75
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Diagnostic utility of combination of inducer and inhibitor based assay in detection of Pseudomonas aeruginosa producing AmpC β-lactamase. J Microbiol Methods 2011; 87:116-8. [DOI: 10.1016/j.mimet.2011.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 07/09/2011] [Accepted: 07/14/2011] [Indexed: 11/23/2022]
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76
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Abstract
Resistance to antimicrobial drugs is increasing at an alarming rate among both gram-positive and gram-negative bacteria. Traditionally, bacteria resistant to multiple antimicrobial agents have been restricted to the nosocomial environment. A disturbing trend has been the recent emergence and spread of resistant pathogens in nursing homes, in the community, and in the hospital. This article reviews the epidemiology, molecular mechanisms of resistance, and treatment options for pathogens resistant to antimicrobial drugs.
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Affiliation(s)
- Luke F Chen
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University Medical Center, Box 102359, Hanes House, Durham, NC 27710, USA.
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77
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Ingram PR, Inglis TJJ, Vanzetti TR, Henderson BA, Harnett GB, Murray RJ. Comparison of methods for AmpC β-lactamase detection in Enterobacteriaceae. J Med Microbiol 2011; 60:715-721. [PMID: 21372181 DOI: 10.1099/jmm.0.029140-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AmpC β-lactamases (Bla(AmpC)) are an emerging group of antimicrobial resistance determinants. The lack of an agreed Bla(AmpC) detection method hinders investigation of their epidemiology and understanding of their clinical significance. This study compared the sensitivity and specificity of phenotypic methods of Bla(AmpC) detection in a collection of 246 Enterobacteriaceae with a diverse range of β-lactam resistance profiles. The Bla(AmpC) screening methods evaluated were based on cephamycin, ceftazidime and cefepime susceptibility. These were compared with Bla(AmpC) screening using conventional ESBL detection methods. The confirmatory methods evaluated were biologically based assays, inhibitor-based assays, an AmpC Etest and a rapid chromogenic assay. A multiplex nucleic acid amplification test and the three-dimensional enzyme extraction assay were used as reference methods. Bla(AmpC) activity was present in 74 isolates. The majority of the enzymes were plasmid-encoded and belonged to the CMY, DHA and EBC families. The screening methods had sensitivities between 47 and 99 % and specificities of 45-95 %. The performance of confirmatory tests varied widely, ranging in sensitivity from 19 % to 97 % and in specificity from 88 % to 100 %. Only the Tris-EDTA and MAST ID D68C disc tests had a sensitivity and a specificity above 90 %. Further investigation is needed to establish the most suitable enzyme substrates, inhibitor types, inhibitor concentrations and interpretative cut-offs in order to refine the inhibitor-based methods. A simple disc-based protocol using cefoxitin non-susceptibility as a screening tool, followed by the Tris-EDTA method for confirmation, detects Bla(AmpC) activity with 95 % sensitivity and 98 % specificity.
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Affiliation(s)
- Paul R Ingram
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Tim J J Inglis
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Tessa R Vanzetti
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Barbara A Henderson
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Gerald B Harnett
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Ronan J Murray
- Department of Microbiology, PathWest Laboratory Medicine, QEII Medical Centre, Nedlands, WA 6009, Australia
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Koczura R, Mokracka J, Krzymińska S, Kaznowski A. Virulence properties and integron-associated antibiotic resistance of Klebsiella mobilis strains isolated from clinical specimens. J Med Microbiol 2011; 60:281-288. [DOI: 10.1099/jmm.0.024059-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
This study examined Klebsiella mobilis isolates cultured from clinical specimens for virulence-associated properties and antibiotic resistance. The strains produced a number of siderophores, including enterobactin, aerobactin and yersiniabactin. All isolates were able to adhere to and invade epithelial cells. They had cytotoxic activity, which caused destruction of human laryngeal epithelial HEp-2 cells and evoked lysis of murine macrophage J774 cells. Analyses of HEp-2 and J774 cellular morphology and DNA fragmentation in the cells showed features typical of cells undergoing apoptosis. Some K. mobilis strains harboured class 1 integrons carrying the aadA1 gene encoding an aminoglycoside adenyltransferase.
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Affiliation(s)
- Ryszard Koczura
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Joanna Mokracka
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Sylwia Krzymińska
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Adam Kaznowski
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
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Mokracka J, Koczura R, Pawłowski K, Kaznowski A. Resistance patterns and integron cassette arrays of Enterobacter cloacae complex strains of human origin. J Med Microbiol 2011; 60:737-743. [PMID: 21330416 DOI: 10.1099/jmm.0.027979-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this research was to analyse the resistance patterns and characterize the distribution and genetic content of resistance integrons within Enterobacter cloacae complex strains originating from hospitalized patients. The strains were included in the E. cloacae complex study following sequence analysis of the hsp60 gene. The determination of resistance towards eight classes of antimicrobials was followed by PCR detection of integrons and analyses of the size and sequences of their variable parts. The majority of 69 clinical strains of the E. cloacae complex were identified as Enterobacter hormaechei. They were isolated from a variety of samples, including urine, wounds, blood and stools. The remaining isolates belonged to E. cloacae clusters III and IV, E. cloacae subsp. cloacae and Enterobacter kobei. Fifty-two isolates (75.4 %) were resistant to more than three unrelated antibiotics. The resistance for each antibiotic, except imipenem, was significantly associated with the presence of integrons. Class 1 integrons were detected in 55 % of isolates: 63.3 % of 'E. hormaechei subsp. steigerwaltii', 50 % of E. cloacae cluster III, 40 % of 'E. hormaechei subsp. oharae', 33 % belonging to E. cloacae cluster IV and 20 % of 'E. hormaechei subsp. hormaechei' were intI1-positive. All of the integrons were located on transferable genetic elements. The transferred resistance primarily included that to aminoglycosides, ticarcillin, piperacillin, sulfamethoxazole, trimethoprim and tetracycline. Sequence analysis of the variable regions of integrons identified two groups of genes: those encoding aminoglycoside adenylotransferases responsible for resistance to aminoglycosides, and dfr cassettes conferring resistance to trimethoprim. Integrons of the E. cloacae complex showed limited variability of genes encoding resistance to therapeutics and were stable in structure with the following cassette arrays: dfrA12-orfF-aadA2, aadB-aadA2, dfrA1-aadA1 and aacA4-aadA1. Hospital-dependent differences in type and arrays of gene cassettes were observed, which seemed to be conserved and not liable to changes.
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Affiliation(s)
- Joanna Mokracka
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Ryszard Koczura
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Konrad Pawłowski
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
| | - Adam Kaznowski
- Department of Microbiology, Faculty of Biology, A. Mickiewicz University, Poznań, Poland
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80
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Upadhyay S, Sen MR, Bhattacharjee A. Diagnostic utility of boronic acid inhibition with different cephalosporins against Escherichia coli producing AmpC β-lactamases. J Med Microbiol 2011; 60:691-3. [PMID: 21292860 DOI: 10.1099/jmm.0.026310-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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81
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Joseph NM, Sistla S, Dutta TK, Badhe AS, Parija SC. Ventilator-associated pneumonia: a review. Eur J Intern Med 2010; 21:360-8. [PMID: 20816584 DOI: 10.1016/j.ejim.2010.07.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/24/2010] [Accepted: 07/08/2010] [Indexed: 01/08/2023]
Abstract
Ventilator-associated pneumonia (VAP) is the most frequent intensive-care-unit (ICU)-acquired infection, with an incidence ranging from 6 to 52% [1,2,3,4]. Several studies have shown that critically ill patients are at high risk for getting such nosocomial infections [3,4]. VAP continues to be a major cause of morbidity, mortality and increased financial burden in ICUs [5,6,7,8]. Over the years there has been a significant advance in our understanding of ventilator associated pneumonia. This article reviews the various aspects of VAP such as definition, risk factors, etiological agents, diagnosis, treatment and prevention with emphasis on the recent advances.
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Affiliation(s)
- Noyal Mariya Joseph
- Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Pondicherry, India.
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Mohamudha Parveen R, Harish BN, Parija SC. Ampc Beta lactamases among gram negative clinical isolates from a tertiary hospital, South India. Braz J Microbiol 2010; 41:596-602. [PMID: 24031534 PMCID: PMC3768642 DOI: 10.1590/s1517-83822010000300009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Revised: 12/10/2009] [Accepted: 03/16/2010] [Indexed: 01/25/2023] Open
Abstract
AmpC β-lactamases are cephalosporinases that hydrolyze cephamycins as well as other extended-spectrum cephalosporins and are poorly inhibited by clavulanic acid. Although reported with increasing frequency, the true rate of occurrence of AmpC β-lactamases in different organisms, including members of Enterobacteriaceae, remains unknown. The present study was designed to determine the occurrence of AmpC enzyme-harbouring Gram-negative clinical isolates in a tertiary care hospital in Pondicherry state, South India. A total of 235 Gram negative clinical isolates were tested for resistance to cefoxitin, third generation cephalosporin (3GC) antibiotics, ampicillin, amikacin, co-trimoxazole, gentamicin, meropenem and tetracycline by disc diffusion method. Isolates found resistant to 3GC and cefoxitin were tested for the production of AmpC β -lactamases by three dimensional extraction method and AmpC disc method. Isolates found to sensitive to 3GC were subjected to disc antagonism test for inducible AmpC production. One hundred and thirty four (57%) strains were resistant to 3GC, among which 63(47%) were positive for plasmid-mediated AmpC beta lactamases production. Among the 101 strains sensitive to 3GC, 23 (22.7%) revealed the presence of inducible AmpC beta lactamases by disc approximation test. A total of 80.9% (51/63) of screen positive isolates were detected by Amp C disc test and 93.6% (59/63) by three dimensional extraction method. Out of the 86 AmpC producers, 67 (77.9%) were cefoxitin resistant .Inducible AmpC was not found in Esch.coli and Klebsiella spp. The AmpC producers also concurrently showed multidrug resistance pattern. AmpC producers were found to be prevalent in our hospital and though three dimensional extraction test detects AmpC better, the disk test is easier to perform routinely and is user- friendly.
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Affiliation(s)
- R Mohamudha Parveen
- Department of Microbiology, Jawaharlal Institute of Post Graduate Medical Education and Research , Pondicherry-605006, , South India
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Laboratory surveillance for prospective plasmid-mediated AmpC beta-lactamases in the Kinki region of Japan. J Clin Microbiol 2010; 48:3267-73. [PMID: 20610688 DOI: 10.1128/jcm.02111-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extended-spectrum beta-lactamases, plasmid-mediated AmpC beta-lactamases (PABLs), and plasmid-mediated metallo-beta-lactamases confer resistance to many beta-lactams. In Japan, although several reports exist on the prevalence of extended-spectrum beta-lactamases and metallo-beta-lactamases, the prevalence and characteristics of PABLs remain unknown. To investigate the production of PABLs, a total of 22,869 strains of 4 enterobacterial species, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis, were collected during six 6-month periods from 17 clinical laboratories in the Kinki region of Japan. PABLs were detected in 29 (0.13%) of 22,869 isolates by the 3-dimensional test, PCR analysis, and DNA sequencing analysis. PABL-positive isolates were detected among isolates from 13 laboratories. Seventeen of 13,995 (0.12%) E. coli isolates, 8 of 5,970 (0.13%) K. pneumoniae isolates, 3 of 1,722 (0.17%) K. oxytoca isolates, and 1 of 1,182 (0.08%) P. mirabilis isolates were positive for PABLs. Of these 29 PABL-positive strains, 20 (69.0%), 6 (20.7%), 2 (6.9%), and 1 (3.4%) carried the genes for CMY-2, DHA-1, CMY-8, and MOX-1 PABLs, respectively. Pattern analysis of randomly amplified polymorphic DNA and pulsed-field gel electrophoretic analysis revealed that the prevalence of CMY-2-producing E. coli strains was not due to epidemic strains and that 3 DHA-1-producing K. pneumoniae strains were identical, suggesting their clonal relatedness. In conclusion, the DHA-1 PABLs were predominantly present in K. pneumoniae strains, but CMY-2 PABLs were predominantly present in E. coli strains. The present findings will provide significant information to assist in preventing the emergence and further spread of PABL-producing bacteria.
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84
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Lee W, Jung B, Hong SG, Song W, Jeong SH, Lee K, Kwak HS. Comparison of 3 phenotypic-detection methods for identifying plasmid-mediated AmpC beta-lactamase-producing Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis strains. Korean J Lab Med 2010; 29:448-54. [PMID: 19893354 DOI: 10.3343/kjlm.2009.29.5.448] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasmid-mediated AmpC beta-lactamases (PABLs) have been detected in the strains of Escherichia coli, Klebsiella spp., Proteus mirabilis, and Salmonella spp. PABLs may be difficult to detect and might interfere in the therapeutic and infection-control processes. Although several PABL-detection methods based on phenotypes have been reported, the Clinical and Laboratory Standards Institute currently does not recommend a routine detection method for PABLs. The aim of this study is to compare the performances of 3 phenotypic PABL detection methods. METHODS Total 276 non-duplicated clinical isolates of E. coli (N=97), K. pneumoniae (N=136), and P. mirabilis (N=43) were collected from 14 hospitals in Korea between April and June 2007 in a non-consecutive and non-random manner. Multiplex PCR was performed to detect the PABL genes. Further, 3 phenotypic detection methods-cephamycin-Hodge test, Tris-EDTA (TE) disk test, and combination-disk test with 3-aminophenylboronic acid (BA)-were performed using cefoxitin and cefotetan disks. RESULTS PABL genes were detected by multiplex PCR in 122/276 isolates, including 14/97 E. coli, 105/136 K. pneumoniae, and 3/43 P. mirabilis isolates. The combination-disk test with BA showed higher sensitivity (98.4%), specificity (92.2%), and efficiency (96.3%) than the cephamycin-Hodge (76.2%, 96.1%, and 88.6%, respectively) and the TE-disk (80.3%, 91.6%, and 87.9%, respectively) tests. CONCLUSIONS The combination-disk test with BA is a simple, efficient, and interpretable test that can be applicable in clinical laboratories involved in the detection of PABLs in clinical isolates of E. coli, K. pneumoniae, and P. mirabilis.
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Affiliation(s)
- Wookeun Lee
- Department of Laboratory Medicine, CHA University, Sungnam, Korea
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85
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Chen LF, Chopra T, Kaye KS. Pathogens Resistant to Antibacterial Agents. Infect Dis Clin North Am 2009; 23:817-45, vii. [DOI: 10.1016/j.idc.2009.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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86
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Iabadene H, Messai Y, Ammari H, Alouache S, Verdet C, Bakour R, Arlet G. Prevalence of plasmid-mediated AmpC β-lactamases among Enterobacteriaceae in Algiers hospitals. Int J Antimicrob Agents 2009; 34:340-2. [DOI: 10.1016/j.ijantimicag.2009.05.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 05/18/2009] [Accepted: 05/26/2009] [Indexed: 10/20/2022]
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87
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88
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Naseer U, Haldorsen B, Simonsen GS, Sundsfjord A. Sporadic occurrence of CMY-2-producing multidrug-resistant Escherichia coli of ST-complexes 38 and 448, and ST131 in Norway. Clin Microbiol Infect 2009; 16:171-8. [PMID: 19548922 DOI: 10.1111/j.1469-0691.2009.02861.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clinical isolates of Escherichia coli with reduced susceptibility to oxyimino-cephalosporins and not susceptible to clavulanic acid synergy (n = 402), collected from Norwegian diagnostic laboratories in 2003-2007, were examined for the presence of plasmid-mediated AmpC beta-lactamases (PABLs). Antimicrobial susceptibility testing was performed for beta-lactam and non-beta-lactam antibiotics using Etest and Vitek2, respectively. The AmpC phenotype was confirmed using the boronic acid test. PABL-producing isolates were detected using ampC multiplex-PCR and examined by bla(AmpC) sequencing, characterization of the bla(AmpC) genetic environment, phylogenetic grouping, XbaI- pulsed-field gel electrophoresis (PFGE), multi-locus sequence typed (MLST), plasmid profiling and PCR-based replicon typing. For the PABL-positive isolates (n = 38), carrying bla(CMY-2) (n = 35), bla(CMY-7) (n = 1) and bla(DHA-1) (n = 2), from out- (n = 23) and in-patients (n = 15), moderate-high MICs of beta-lactams, except cefepime and carbapenems, were determined. All isolates were resistant to trimethoprim-sulphamethoxazole. Multidrug resistance was detected in 58% of the isolates. The genes bla(CMY-2) and bla(CMY-7) were linked to ISEcp1 upstream in 32 cases and in one case, respectively, and bla(DHA-1) was linked to qacEDelta1sul1 upstream and downstream in one case. Twenty isolates were of phylogenetic groups B2 or D. Thirty-three XbaI-PFGE types, including three clusters, were observed. Twenty-five sequence types (ST) were identified, of which ST complexes (STC) 38 (n = 7), STC 448 (n = 5) and ST131 (n = 4) were dominant. Plasmid profiling revealed 1-4 plasmids (50-250 kb) per isolate and 11 different replicons in 37/38 isolates; bla(CMY-2) was carried on transferable multiple-replicon plasmids, predominantly of Inc groups I1 (n = 12), FII (n = 10) and A/C (n = 7). Chromosomal integration was observed for bla(CMY-2) in ten strains. CMY-2 is the dominant PABL type in Norway and is associated with ISEcp1 and transferable, multiple-replicon IncI1, IncA/C, or IncFII plasmids in nationwide strains of STC 448, STC 38 and ST131.
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Affiliation(s)
- U Naseer
- Reference Centre for Detection of Antimicrobial Resistance (K-res), Department of Microbiology and Infection Control, University Hospital of North-Norway, Tromsø, Norway.
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Cephalosporin MIC distribution of extended-spectrum-{beta}-lactamase- and pAmpC-producing Escherichia coli and Klebsiella species. J Clin Microbiol 2009; 47:2419-25. [PMID: 19494061 DOI: 10.1128/jcm.00508-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The acquisition of beta-lactamases in members of the Enterobacteriaceae family poses a challenge to antimicrobial susceptibility testing in the clinical laboratory. We correlated the distribution of the MICs for Klebsiella spp. and Escherichia coli with the presence of extended-spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase (pAmpC) genes. A total of 264 isolates were subjected to cefazolin, ceftriaxone, cefotaxime, ceftazidime, cefepime, and aztreonam agar dilution MIC determination; ESBL screening and confirmatory testing by the methods of the Clinical and Laboratory Standards Institute (CLSI); and for isolates for which the MICs of extended-spectrum cephalosporins were > or =1 microg/ml or the MICs of cefpodoxime were >4 microg/ml, PCR amplification and sequencing of the ESBL and pAmpC genes. PCR was positive for 73/81 isolates (45 isolates with an ESBL gene alone, 24 isolates with a pAmpC gene alone, with 4 isolates with both genes). Compared to PCR, confirmatory testing by the CLSI method yielded a sensitivity and a specificity of 98.0 and 96.3%, respectively; there were six false-positive results and one false-negative result. No distinction in the MIC distribution was apparent between isolates with the ESBL gene and isolates with the pAmpC gene. A substantial percentage of the isolates with PCR-confirmed ESBL and/or pAmpC genes fell within the current CLSI susceptible category. For a ceftazidime, ceftriaxone, or cefotaxime MIC of > or =2 microg/ml, a dichotomy existed between isolates with and without ESBL and pAmpC genes in most cases. This suggests that the presence of the ESBL and the pAmpC enzymes may yield similar MICs of extended-spectrum cephalosporins, many of which fall within the current nonresistant categories. Lowering of the current CLSI breakpoints for cephalosporins appears to be warranted.
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Abstract
SUMMARY AmpC beta-lactamases are clinically important cephalosporinases encoded on the chromosomes of many of the Enterobacteriaceae and a few other organisms, where they mediate resistance to cephalothin, cefazolin, cefoxitin, most penicillins, and beta-lactamase inhibitor-beta-lactam combinations. In many bacteria, AmpC enzymes are inducible and can be expressed at high levels by mutation. Overexpression confers resistance to broad-spectrum cephalosporins including cefotaxime, ceftazidime, and ceftriaxone and is a problem especially in infections due to Enterobacter aerogenes and Enterobacter cloacae, where an isolate initially susceptible to these agents may become resistant upon therapy. Transmissible plasmids have acquired genes for AmpC enzymes, which consequently can now appear in bacteria lacking or poorly expressing a chromosomal bla(AmpC) gene, such as Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Resistance due to plasmid-mediated AmpC enzymes is less common than extended-spectrum beta-lactamase production in most parts of the world but may be both harder to detect and broader in spectrum. AmpC enzymes encoded by both chromosomal and plasmid genes are also evolving to hydrolyze broad-spectrum cephalosporins more efficiently. Techniques to identify AmpC beta-lactamase-producing isolates are available but are still evolving and are not yet optimized for the clinical laboratory, which probably now underestimates this resistance mechanism. Carbapenems can usually be used to treat infections due to AmpC-producing bacteria, but carbapenem resistance can arise in some organisms by mutations that reduce influx (outer membrane porin loss) or enhance efflux (efflux pump activation).
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91
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Unreliable extended-spectrum beta-lactamase detection in the presence of plasmid-mediated AmpC in Escherichia coli clinical isolates. J Clin Microbiol 2008; 47:358-61. [PMID: 19109470 DOI: 10.1128/jcm.01687-08] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The emergence of extended-spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC (pAmpC) enzymes in Escherichia coli raises concern regarding accurate laboratory detection and interpretation of susceptibility testing results. Twenty-six cefpodoxime ESBL screen-positive, cefoxitin-resistant E. coli clinical isolates were subjected to clavulanate ESBL confirmatory testing employing disk augmentation, Etest, and the BD Phoenix NMC/ID-132 panel. Phenotypic pAmpC production was assessed by boronic acid disk augmentation. ESBL and pAmpC genes were detected by gene amplification and sequencing. ESBL genes (SHV and/or CTX-M-type genes) were detected in only 7/26 ESBL screen-positive isolates. Of 23 aminophenylboronic acid screen-positive isolates, pAmpC genes were detected in 20 (CMY-2 or FOX-5 genes). High incidences of false-positive ESBL confirmatory results were observed for both clavulanate disk augmentation (9/19) and BD Phoenix (5/19). All were associated with the presence of pAmpC genes with or without TEM-1. Etest performed poorly, as the majority of interpretations were nondeterminable. In addition, false-negative ESBL confirmatory results were observed in isolates possessing concomitant ESBL and pAmpC genes for Etest (four of five), BD Phoenix (three of five), and disk augmentation (one of five). The results indicate poor performance of currently employed ESBL confirmatory methods in the setting of concomitant pAmpC. Some isolates with pAmpC and ESBL genes fell within the susceptible category to extended-spectrum cephalosporins, raising concern over currently employed breakpoints.
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92
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Al Muharrmi Z, Rafay AM, Balkhair A, Al-Tamemi S, Al Mawali A, Al Sadiri H. Extended-spectrum β-lactamase (ESBL) in Omani Children: Study of prevalence, risk factors and clinical outcomes at Sultan Qaboos University Hospital, Sultanate of Oman. Sultan Qaboos Univ Med J 2008; 8:171-177. [PMID: 21748055 PMCID: PMC3074824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2007] [Accepted: 03/31/2008] [Indexed: 05/31/2023] Open
Abstract
OBJECTIVES Antimicrobial resistance is a growing problem worldwide, which imposes difficulties in the selection of appropriate empirical antimicrobial therapy. This study evaluated extended-spectrum β-lactamase (ESBL) isolates in 2005 in The Department of Child Health at Sultan Qaboos University Hospital (SQUH), Oman. METHODS During the 12 month period from January 2005 to December 2005, ESBL isolates from paediatrics inpatients were identified and analysed. Risk factors for the patients who grew ESBLs were analysed. RESULTS 13.3% of E. coli and 16.6% of Klebsiella pneumoniae isolated were ESBL producers. Most of the ESBLs were from urine (46.2%) and blood (42.6%). The main risk factors for ESBL in these children were previous exposure to antimicrobials (100%), prolonged hospital stay, severe illness (92.3%) and female gender (84.6%). Sensitivity of 100% was observed to carbapenems whereas 92% of the isolates were susceptible to amikacin. The oximino-cephalosporins were 100% resistant. Klebsiella pneumoniae were 100% resistant to piperacillin-tazobactam and nitrofurantoin. E. coli was 100% resistant to trimethoprim-sulfamethoxazole and ciprofloxacin. No resistance was recorded for the following combinations: amikacin plus piperacillin-tazobactam, amikacin plus nitrofurantoin and gentamicin plus nitrofurantoin. CONCLUSION ESBL-producing organisms are becoming a major problem in Omani children. Exposure to antimicrobials and long admissions are modifiable risk factors that should be targeted for better control. Carbapenems are the most sensitive and reliable treatment options for infections caused by ESBLs. Amikacin plus piperacillin-tazobactam or nitrofurantoin are good alternatives.
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Affiliation(s)
| | | | | | - Salem Al-Tamemi
- Child Health, Sultan Qaboos University Hospital, Muscat, Oman
| | - Ali Al Mawali
- Medical Student, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Hilal Al Sadiri
- Medical Student, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
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Prevalent phenotypes and antibiotic resistance in Escherichia coli and Klebsiella pneumoniae at an Indian tertiary care hospital: plasmid-mediated cefoxitin resistance. Int J Infect Dis 2008; 12:256-64. [DOI: 10.1016/j.ijid.2007.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2006] [Revised: 08/18/2007] [Accepted: 08/30/2007] [Indexed: 11/20/2022] Open
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Prevalence of plasmid-mediated AmpC beta-lactamases in a Chinese university hospital from 2003 to 2005: first report of CMY-2-Type AmpC beta-lactamase resistance in China. J Clin Microbiol 2008; 46:1317-21. [PMID: 18305137 DOI: 10.1128/jcm.00073-07] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to investigate the prevalences of plasmid-mediated AmpC beta-lactamases (PABLs) in isolates of Escherichia coli and Klebsiella spp. from a university hospital in China. A total of 1,935 consecutive nonrepeat clinical isolates of Escherichia coli, Klebsiella pneumoniae, and Klebsiella oxytoca were collected between January 2003 and July 2005. The isolates with cefoxitin zone diameters less than 18 mm (screen positive) were selected for PCR of the bla(AmpC) genes and sequencing. Fifty-four (2.79%) isolates harbored PABLs, as demonstrated by PCR and isoelectric focusing. Sequence analysis revealed the presence of bla(DHA-1) and bla(CMY-2) genes. The Southern blot hybridization studies confirmed that bla(CMY-2) and bla(DHA-1) were located on plasmids. Based on species, PABLs were detected in 4.29% (29 isolates of DHA-1 and 1 isolate of CMY-2) of K. pneumoniae, 1.91% (11 isolates of DHA-1 and 12 isolates of CMY-2) of E. coli, and 3.03% (1 isolate of DHA-1) of K. oxytoca isolates. In contrast to our anticipation, the occurrence rate of DHA-1-producing K. pneumonia significantly decreased (P < 0.01), from 7.54% in 2003 to 2.72% in 2004. The results of random amplified polymorphic DNA analysis indicate that the prevalences of DHA-1-producing K. pneumoniae and CMY-2-producing E. coli strains were not due to epidemic strains. In conclusion, DHA-1 was the most prevalent acquired AmpC beta-lactamase in this collection of isolates from a medical center in China, and DHA-1-producing K. pneumoniae was the most prevalent bacterium harboring a PABL. To the best of our knowledge, this is the first report of CMY-2-type AmpC beta-lactamases in the Chinese mainland.
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Dias RCDS, Borges-Neto AA, Ferraiuoli GID, de-Oliveira MP, Riley LW, Moreira BM. Prevalence of AmpC and other beta-lactamases in enterobacteria at a large urban university hospital in Brazil. Diagn Microbiol Infect Dis 2007; 60:79-87. [PMID: 17900845 PMCID: PMC2894158 DOI: 10.1016/j.diagmicrobio.2007.07.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 07/23/2007] [Accepted: 07/24/2007] [Indexed: 11/30/2022]
Abstract
Production of extended-spectrum beta-lactamases (ESBLs) has been reported in virtually all species of Enterobacteriaceae, which greatly complicates the therapy for infections caused by these organisms. However, the frequency of isolates producing AmpC beta-lactamases, especially plasmid-mediated AmpC (pAmpC), is largely unknown. These beta-lactamases confer resistance to extended-spectrum cephalosporins and aztreonam, a multidrug-resistant (MDR) profile. The aim of the present study was to determine the occurrence of ESBL and pAmpC beta-lactamases in a hospital where MDR enterobacterial isolates recently emerged. A total of 123 consecutive enterobacterial isolates obtained from 112 patients at a university hospital in Rio de Janeiro, Brazil, during March to June 2001 were included in the study. ESBL was detected by the addition of clavulanate to cephalosporin containing disks and by double diffusion. AmpC production was evaluated by a modified tridimensional test and a modified Hodge test. The presence of plasmid-mediated ampC beta-lactamase genes was evaluated by multiplex polymerase chain reaction. Sixty-five (53%) of 123 enterobacterial isolates were MDR obtained from 56 patients. ESBL production was detected in 35 isolates; 5 clonal Escherichia coli isolates exhibited high levels of chromosomal AmpC and ESBL production. However, no isolates contained pAmpC genes. Infection or colonization by MDR enterobacteria was not associated with any predominant resistant clones. A large proportion of hospital infections caused by ESBL-producing enterobacteria identified during the study period were due to sporadic infections rather than undetected outbreaks. This observation emphasizes the need to improve our detection methods for ESBL- and AmpC-producing organisms in hospitals where extended-spectrum cephalosporins are in wide use.
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Affiliation(s)
| | | | | | - Márcia P. de-Oliveira
- Hospital Universitário Clementino Fraga Filho of Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lee W. Riley
- School of Public Health, University of California, Berkeley, California
| | - Beatriz Meurer Moreira
- Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Hospital Universitário Clementino Fraga Filho of Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Corresponding author: Beatriz Meurer Moreira, M.D., Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Centro de Ciências da Saúde, Bloco I, Av. Carlos Chagas Filho, 373. Cidade Universitária, Rio de Janeiro, RJ 21941-902, Brazil, Phone: 55-21-25626745/Fax: 55-21-22608344/
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Doi Y, Paterson DL. Detection of plasmid-mediated class C β-lactamases. Int J Infect Dis 2007; 11:191-7. [PMID: 17339123 DOI: 10.1016/j.ijid.2006.07.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Revised: 07/18/2006] [Accepted: 07/27/2006] [Indexed: 10/23/2022] Open
Abstract
Plasmid-mediated class C beta-lactamases are reported from Enterobacteriaceae with increasing frequency. They likely originate from chromosomal AmpC of certain Gram-negative bacterial species and subsequently are mobilized onto transmissible plasmids. There are reports of unfavorable clinical outcomes in patients infected with these organisms and treated with broad-spectrum cephalosporins. However, unlike class A extended-spectrum beta-lactamases (ESBLs), no screening and confirmatory tests have been uniformly established for strains that produce class C beta-lactamases. Reduced susceptibility to cefoxitin is a sensitive but not specific indicator of class C beta-lactamase production. Simple confirmatory tests including tests using boronic acid compounds as specific class C beta-lactamase inhibitors have recently been developed. Their utilization will enable clinical microbiology laboratories to report those strains producing plasmid-mediated class C beta-lactamases as being resistant to all broad-spectrum cephalosporins, thus allowing physicians to prescribe appropriate antimicrobial therapy.
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Affiliation(s)
- Yohei Doi
- Division of Infectious Diseases, University of Pittsburgh Medical Center, Falk Medical Building Suite 3A, 3601 Fifth Avenue, Pittsburgh, PA 15213, USA
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Sinha M, Srinivasa H. MECHANISMS OF RESISTANCE TO CARBAPENEMS IN MEROPENEM-RESISTANT ACINETOBACTER ISOLATES FROM CLINICAL SAMPLES. Indian J Med Microbiol 2007. [DOI: 10.1016/s0255-0857(21)02169-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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98
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Navaneeth BV. Extended-spectrum and AmpC beta-lactamases in Escherichia coli and Klebsiella pneumoniae from a rural South Indian tertiary care hospital. Int J Antimicrob Agents 2007; 29:602-3. [PMID: 17296286 DOI: 10.1016/j.ijantimicag.2006.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 12/07/2006] [Accepted: 12/07/2006] [Indexed: 10/23/2022]
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Yu Y, Ji S, Chen Y, Zhou W, Wei Z, Li L, Ma Y. Resistance of strains producing extended-spectrum β-lactamases and genotype distribution in China. J Infect 2007; 54:53-7. [PMID: 16533535 DOI: 10.1016/j.jinf.2006.01.014] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Accepted: 01/22/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To investigate the resistance of Escherichia coli and Klebsiella pneumoniae producing extended-spectrum beta-lactamases (ESBLs) and the genotyping of ESBLs in China. METHODS MICs of 12 antibiotics against 50 strains (by random selection) of ESBLs-producing E. coli and K. pneumoniae were determined by E-test. The genotypes of ESBLs were analyzed by PCR, DNA sequencing and isoelectric focusing. RESULTS The susceptibility rate of 50 isolates was 100% in imipenem, 60%-80% in cefoperazone/sulbactam, ceftazidime and piperacillin/tazobactam, and lower in other antimicrobial agents tested. Only 6.0% of the isolates were sensitive to cefotaxime. Four hundred and forty-seven of 509 isolates had been confirmed the genotype of ESBLs. Four hundred and sixteen strains produced only one type of ESBLs, including CTX-M-14 (271 strains), CTX-M-3 (70 strains), CTX-M-24 (35 strains), CTX-M-22 (8 strains), CTX-M-15 (4 strains), CTX-M-9 (4 strains), CTX-M-28 (3 strains), CTX-M-12 (1 strain), CTX-M-13 (1 strain), CTX-M-27 (1 strain), CTX-M-29 (1 strain), SHV-12 (10 strains), SHV-5 (4 strains), SHV-2 (2 strains), and SHV-9 (1 strain). Thirty isolates carried two or three types of ESBLs, and producing CTX-M-14 and CTX-M-3 together were the most common type. CONCLUSION The resistance of E. coli and K. pneumonia producing ESBLs in China was a serious issue and CTX-M type ESBLs were the most common genotype. CTX-M-14 was the predominant genotype. Some isolates produced two or three ESBLs.
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Affiliation(s)
- Yunsong Yu
- Department of Infectious Diseases, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
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Song W, Jeong SH, Kim JS, Kim HS, Shin DH, Roh KH, Lee KM. Use of boronic acid disk methods to detect the combined expression of plasmid-mediated AmpC beta-lactamases and extended-spectrum beta-lactamases in clinical isolates of Klebsiella spp., Salmonella spp., and Proteus mirabilis. Diagn Microbiol Infect Dis 2006; 57:315-8. [PMID: 17174510 DOI: 10.1016/j.diagmicrobio.2006.08.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 08/02/2006] [Accepted: 08/29/2006] [Indexed: 11/20/2022]
Abstract
A study using boronic acid (BA), an AmpC enzyme inhibitor, was designed to detect the combined expression of plasmid-mediated AmpC beta-lactamases (pAmpCs) and extended-spectrum beta-lactamases (ESBLs) in bacterial isolates naturally lacking chromosomal ampC genes. A total of 122 Klebsiella spp., Salmonella spp., and Proteus mirabilis isolates producing or nonproducing pAmpCs and/or ESBLs were analyzed. Detection of genes encoding ESBLs and AmpCs was confirmed by polymerase chain reaction (PCR) followed by sequencing of PCR products. A > or = 5-mm increase in zone diameter for i) cefoxitin (FOX) and/or cefotetan (CTT) containing BA versus FOX and/or CTT alone was considered positive for AmpC; ii) ceftazidime (CAZ)-clavulanate (CA) and/or cefotaxime (CTX)-CA tested in combination with BA versus CAZ and/or CTX containing BA was considered positive for ESBL. The disk tests of FOX and/or CTT alone and with BA detected 98.4% of organisms producing pAmpCs. All of the 21 pAmpC and ESBL coproducers were accurately detected ESBL by the disk tests of CTX-CA and/or CAZ-CA containing BA and CTX and/or CAZ containing BA. In conclusion, The BA disk test using Clinical and Laboratory Standards Institute methodology is simple and very efficient method to detect pAmpC and ESBL in organisms naturally lacking chromosomal AmpC enzymes. In particular, the method accurately detects the isolates that harbor both AmpCs and ESBLs.
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Affiliation(s)
- Wonkeun Song
- Department of Laboratory Medicine, Hallym University College of Medicine, Seoul, South Korea
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