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Prediction of Fluoroquinolone Susceptibility Directly from Whole-Genome Sequence Data by Using Liquid Chromatography-Tandem Mass Spectrometry To Identify Mutant Genotypes. Antimicrob Agents Chemother 2018; 62:AAC.01814-17. [PMID: 29263066 DOI: 10.1128/aac.01814-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/29/2017] [Indexed: 02/05/2023] Open
Abstract
Fluoroquinolone resistance in Gram-negative bacteria is multifactorial, involving target site mutations, reductions in fluoroquinolone entry due to reduced porin production, increased fluoroquinolone efflux, enzymes that modify fluoroquinolones, and Qnr, a DNA mimic that protects the drug target from fluoroquinolone binding. Here we report a comprehensive analysis, using transformation and in vitro mutant selection, of the relative importance of each of these mechanisms for fluoroquinolone nonsusceptibility using Klebsiella pneumoniae as a model system. Our improved biological understanding was then used to generate 47 rules that can predict fluoroquinolone susceptibility in K. pneumoniae clinical isolates. Key to the success of this predictive process was the use of liquid chromatography-tandem mass spectrometry to measure the abundance of proteins in extracts of cultured bacteria, identifying which sequence variants seen in the whole-genome sequence data were functionally important in the context of fluoroquinolone susceptibility.
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2
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Peptide nucleic acids (PNAs): currently potential bactericidal agents. Biomed Pharmacother 2017; 93:580-588. [PMID: 28686972 DOI: 10.1016/j.biopha.2017.06.092] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/12/2017] [Accepted: 06/23/2017] [Indexed: 01/09/2023] Open
Abstract
In recent years, the emergence of ESBL-producing and multi-drug resistant bacteria have been increased and designing novel components is necessary for confrontation these bacteria. Peptide nucleic acids (PNAs) are one of the synthetic components that bind to single strand DNA and RNA. Applications of these components are wide while, and one of the important applications of these components is inhibition of gene expression and knock downing the target gene follow as inhibition of bacterial growth. For PNA targeting gene, peptide-PNAs (PPNA) activity cannot be occurred without sequence homology, at the same time, it has been affected by sequence-based specific target and dose-dependent-based manner. Choosing the conserved sequence in different bacterial genus can provide broad-spectrum antimicrobial activity. In this review article, we studied several research papers and extract PNA targeting genes that cause gene knock down and inhibition of bacterial growth. Some novel opportunities for advancement and the design ultra-narrow-spectrum antimicrobial drugs against multi-drug can be accessible by utilizing PNA against necessary genes of pathogens. These results open novel vision for therapeutic intervention. Future researches are required to evaluate the safety, toxicity and pharmacokinetics properties of PPNAs in order to be utilized in clinical treatment.
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Jayme MMA, Castro RO, Silva CAM, Silva MM, Carmo FLD, Araujo FVD. Evaluation of the biotechnological potential of bacterioplankton from Niterói coast, RJ. C R Biol 2017; 340:324-329. [DOI: 10.1016/j.crvi.2017.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/31/2017] [Accepted: 06/06/2017] [Indexed: 11/29/2022]
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Paiva MC, Reis MP, Costa PS, Dias MF, Bleicher L, Scholte LLS, Nardi RMD, Nascimento AMA. Identification of new bacteria harboring qnrS and aac(6')-Ib/cr and mutations possibly involved in fluoroquinolone resistance in raw sewage and activated sludge samples from a full-scale WWTP. WATER RESEARCH 2017; 110:27-37. [PMID: 27984803 DOI: 10.1016/j.watres.2016.11.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
Wastewater treatment plants (WWTPs) harbor bacteria and antimicrobial resistance genes, favoring gene exchange events and resistance dissemination. Here, a culture-based and metagenomic survey of qnrA, qnrB, qnrS, and aac(6')-Ib genes from raw sewage (RS) and activated sludge (AS) of a full-scale municipal WWTP was performed. A total of 96 bacterial isolates were recovered from nalidixic acid-enrichment cultures. Bacteria harboring the aac(6')-Ib gene predominated in RS, whereas qnrS-positive isolates were specific to AS. Novel qnrS- and aac(6')-Ib-cr positive species were identified: Morganella morganii, Providencia rettgeri, and Pseudomonas guangdongensis (qnrS), and Alcaligenes faecalis and P. rettgeri (aac(6')-Ib-cr). Analysis of qnrS and aac(6')-Ib sequences from isolates and clone libraries suggested that the diversity of qnrS is wider than that of aac(6')-Ib. A large number of amino acid mutations were observed in the QnrS and AAC(6')-Ib proteins at previously undetected positions, whose structural implications are not clear. An accumulation of mutations at the C72, Q73, L74, A75 and M76 positions of QnrS, and D181 of AAC(6')-Ib might be important for resistance. These findings add significant information on bacteria harboring qnrS and aac(6')-Ib genes, and the presence of novel mutations that may eventually emerge in clinical isolates.
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Affiliation(s)
- Magna C Paiva
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil; Campus Dona Lindu, Universidade Federal de São João del Rei, Divinópolis, Minas Gerais, Brazil
| | - Mariana P Reis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Patrícia S Costa
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Marcela F Dias
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lucas Bleicher
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Larissa L S Scholte
- Centro de Pesquisas René Rachou - FIOCRUZ, Belo Horizonte, Minas Gerais, Brazil
| | - Regina M D Nardi
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Andréa M A Nascimento
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
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Rocha FR, Pinto VPT, Barbosa FCB. The Spread of CTX-M-Type Extended-Spectrum β-Lactamases in Brazil: A Systematic Review. Microb Drug Resist 2016; 22:301-11. [DOI: 10.1089/mdr.2015.0180] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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6
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Rodriguez-Martinez JM, Machuca J, Calvo J, Diaz-de-Alba P, Rodríguez-Mirones C, Gimeno C, Martinez-Martinez L, Pascual Á. Challenges to accurate susceptibility testing and interpretation of quinolone resistance in Enterobacteriaceae: results of a Spanish multicentre study. J Antimicrob Chemother 2015; 70:2038-47. [PMID: 25745103 DOI: 10.1093/jac/dkv059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/11/2015] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES The objective of this study was to evaluate the proficiency of Spanish laboratories with respect to accurate susceptibility testing and the detection and interpretation of quinolone resistance phenotypes in Enterobacteriaceae. METHODS Thirteen strains of Enterobacteriaceae were sent to 62 participating centres throughout Spain; strains harboured GyrA/ParC modifications, reduced permeability and/or plasmid-mediated quinolone resistance genes. The centres were requested to evaluate nalidixic acid and five quinolones, provide raw/interpreted clinical categories and to detect/infer resistance mechanisms. Consensus results from reference centres were used to assign minor, major and very major errors (mEs, MEs and VMEs, respectively). RESULTS Susceptibility testing in the participating centres was frequently performed using the MicroScan WalkAway, Vitek 2 and Wider systems (48%, 30% and 8%, respectively). CLSI/EUCAST breakpoints were used in 71%/29% of the determinations. The percentage of VMEs for all quinolones was well below 2%. Only ofloxacin and moxifloxacin showed higher values for raw VMEs (6.6%), which decreased to 0% and 2.9%, respectively, in the interpreted VMEs. These errors were particularly associated with the CC-03 strain [qnrS2 + aac(6')-Ib-cr]. For MEs, percentages were always <10%, except in the case of ofloxacin and nalidixic acid. There was a significantly higher percentage of all types of errors for strains whose MICs were at the border of clinical breakpoints. CONCLUSIONS The use of different breakpoints and methods, the complexity of mutation-driven and transferable resistance mechanisms and the absence of specific tests for detecting low-level resistance lead to high variability and represent a challenge to accuracy in susceptibility testing, particularly in strains with MICs on the border of clinical breakpoints.
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Affiliation(s)
- José-Manuel Rodriguez-Martinez
- Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Machuca
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain
| | - Jorge Calvo
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | | | - Cristina Rodríguez-Mirones
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain
| | - Concha Gimeno
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain
| | - Luis Martinez-Martinez
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Álvaro Pascual
- Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain
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7
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Ferrari R, Galiana A, Cremades R, Rodríguez JC, Magnani M, Tognim MCB, Oliveira TCRM, Royo G. Plasmid-mediated quinolone resistance (PMQR) and mutations in the topoisomerase genes of Salmonella enterica strains from Brazil. Braz J Microbiol 2013; 44:651-6. [PMID: 24294265 PMCID: PMC3833171 DOI: 10.1590/s1517-83822013000200046] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 07/23/2012] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to identify mutations in the Quinolone Resistance Determining sources Regions (QRDR) of the gyrA, gyrB, parC, and parE genes and to determine if any of the qnr variants or the aac(6')-Ib-cr variant were present in strains of Salmonella spp. isolated in Brazil. A total of 126 Salmonella spp. strains from epidemic (n = 114) and poultry (n = 12) origin were evaluated. One hundred and twelve strains (88.8%) were resistant to nalidixic acid (NAL) and 29 (23.01%) showed a reduced susceptibility to ciprofloxacin (Cip). The mutations identified were substitutions limited to the QRDR of the gyrA gene in the codons for Serine 83, Aspartate 87 and Alanine 131. The sensitivity to NAL seems to be a good phenotypic indication of distinguishing mutated and non-mutated strains in the QRDR, however the double mutation in gyrA did not cause resistance to ciprofloxacin. The qnrA1 and qnrB19 genes were detected, respectively, in one epidemic strain of S. Enteritidis and one strain of S. Corvallis of poultry origin. Despite previous detection of qnr genes in Brazil, this is the first report of qnr gene detection in Salmonella, and also the first detection of qnrB19 gene in this country. The results alert for the continuous monitoring of quinolone resistance determinants in order to minimize the emergence and selection of Salmonella spp. strains showing reduced susceptibility or resistance to quinolones.
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Affiliation(s)
- Rafaela Ferrari
- Departamento de Ciência e Tecnologia de Alimentos, Centro de Ciências Agrárias, Universidade Estadual de Londrina, Londrina, PR, Brazil
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8
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Paiva MC, Nascimento AMA, Camargo ILBC, Lima-Bittencourt CI, Nardi RMD. The first report of the qnrB19, qnrS1 and aac(6´)-Ib-cr genes in urinary isolates of ciprofloxacin-resistant Escherichia coli in Brazil. Mem Inst Oswaldo Cruz 2013; 107:687-9. [PMID: 22850962 DOI: 10.1590/s0074-02762012000500018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 02/15/2012] [Indexed: 11/22/2022] Open
Abstract
In this study, we investigated the presence of plasmid-mediated quinolone resistance (PMQR) genes among 101 ciprofloxacin-resistant urinary Escherichia coli isolates and searched for mutations in the quinolone-resistance-determining regions (QRDRs) of the DNA gyrase and topoisomerase IV genes in PMQR-carrying isolates. Eight isolates harboured the qnr and aac(6')-Ib-cr genes (3 qnrS1, 1 qnrB19 and 4 aac(6')-Ib-cr). A mutational analysis of the QRDRs in qnr and aac(6')-Ib-cr-positive isolates revealed mutations in gyrA, parC and parE that might be associated with high levels of resistance to quinolones. No mutation was detected in gyrB. Rare gyrA, parC and parE mutations were detected outside of the QRDRs. This is the first report of qnrB19, qnrS1 and aac(6')-Ib-cr -carrying E. coli isolates in Brazil.
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Affiliation(s)
- Magna Cristina Paiva
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil, 31270-901
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Klebsiella pneumoniae AcrAB efflux pump contributes to antimicrobial resistance and virulence. Antimicrob Agents Chemother 2009; 54:177-83. [PMID: 19858254 DOI: 10.1128/aac.00715-09] [Citation(s) in RCA: 271] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Respiratory infections caused by Klebsiella pneumoniae are characterized by high rates of mortality and morbidity. Management of these infections is often difficult, due to the high frequency of strains that are resistant to multiple antimicrobial agents. Multidrug efflux pumps play a major role as a mechanism of antimicrobial resistance in Gram-negative pathogens. In the present study, we investigated the role of the K. pneumoniae AcrRAB operon in antimicrobial resistance and virulence by using isogenic knockouts deficient in the AcrB component and the AcrR repressor, both derived from the virulent strain 52145R. We demonstrated that the AcrB knockout was more susceptible, not only to quinolones, but also to other antimicrobial agents, including beta-lactams, than the wild-type strain and the AcrR knockout. We further showed that the AcrB knockout was more susceptible to antimicrobial agents present in human bronchoalveolar lavage fluid and to human antimicrobial peptides than the wild-type strain and the AcrR knockout. Finally, the AcrB knockout exhibited a reduced capacity to cause pneumonia in a murine model, in contrast to the wild-type strain. The results of this study suggest that, in addition to contributing to the multidrug resistance phenotype, the AcrAB efflux pump may represent a novel virulence factor required for K. pneumoniae to resist innate immune defense mechanisms of the lung, thus facilitating the onset of pneumonia.
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dos Santos DF, Pimenta FC, Alves R, Montalvão ER, dos Santos DB, do Carmo Filho JR. Extended-spectrum β-lactamases producing Klebsiella pneumoniae isolated in two hospitals in Goiânia/Brazil: detection, prevalence, antimicrobial susceptibility and molecular typing. Braz J Microbiol 2008; 39:608-12. [PMID: 24031275 PMCID: PMC3768459 DOI: 10.1590/s1517-83822008000400002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 11/04/2007] [Accepted: 11/02/2008] [Indexed: 11/22/2022] Open
Abstract
This study was developed to evaluate the prevalence of extended-spectrum β-lactamases (ESBL) producing Klebsiella pneumoniae in two hospitals (A and B) in Goiânia, GO, Brazil. The antimicrobial susceptibility of the isolates was determined using the MicroScan WalkAway (Dade Behring, USA). Tests to evaluate the genetic correlation between the isolates were also performed. For the ESBL phenotypic test, the Double-disk diffusion (DD) method was used. The strains isolated in Hospital B were submitted to DNA analysis by pulsed-field gel electrophoresis (PFGE). The study showed high prevalence of ESBL-producing K. pneumoniae (25% in hospital A and 66.7% in hospital B), with high rates of antimicrobial resistance. The most active compound was imipenem (100% susceptibility in vitro). The PFGE test showed similiarity in five strains and variability in six strains.The high prevalence of ESBL-producing Klebsiella may be due to individual selection and to dissemination of a common strain.
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Alteration of GyrA amino acid required for ciprofloxacin resistance in Klebsiella pneumoniae isolates in China. Antimicrob Agents Chemother 2008; 52:2980-3. [PMID: 18505849 DOI: 10.1128/aac.00151-08] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Resistance to ciprofloxacin was detected in 111 (48.1%) isolates of Klebsiella pneumoniae from China. GyrA alterations were identified in the ciprofloxacin-resistant and ciprofloxacin-susceptible isolates. The results, including previously published data, indicate that the single substitution Ser83-->Ile and three types of double mutations at Ser83 and Asp87 were required for ciprofloxacin resistance (P < 0.05).
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12
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Pérez-Vázquez M, Román F, García-Cobos S, Campos J. Fluoroquinolone resistance in Haemophilus influenzae is associated with hypermutability. Antimicrob Agents Chemother 2007; 51:1566-9. [PMID: 17283196 PMCID: PMC1855460 DOI: 10.1128/aac.01437-06] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Forty-three percent (12/28) of ciprofloxacin (CIP)-nonsusceptible respiratory isolates of Haemophilus influenzae were hypermutable, compared with 8.5% (3/35) in the CIP-susceptible control group (P=0.002). CIP-nonsusceptible mutants were obtained with hypermutable strains only; these mutants developed three resistance mechanisms in a step-by-step process: target modifications, loss of a porin protein, and increased efflux.
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Affiliation(s)
- María Pérez-Vázquez
- Antibiotic Laboratory, Bacteriology Service, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
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13
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Abstract
Antibiotic resistance continues to hamper antimicrobial chemotherapy of infectious disease, and while biocide resistance outside of the laboratory is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are not uncommon. Efflux mechanisms, both drug-specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials in important human pathogens. Multidrug efflux mechanisms are generally chromosome-encoded, with their expression typically resultant from mutations in regulatory genes, while drug-specific efflux mechanisms are encoded by mobile genetic elements whose acquisition is sufficient for resistance. While it has been suggested that drug-specific efflux systems originated from efflux determinants of self-protection in antibiotic-producing Actinomycetes, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, are appreciated as having an intended housekeeping function unrelated to drug export and resistance. Thus, it will be important to elucidate the intended natural function of these efflux mechanisms in order, for example, to anticipate environmental conditions or circumstances that might promote their expression and, so, compromise antimicrobial chemotherapy. Given the clinical significance of antimicrobial exporters, it is clear that efflux must be considered in formulating strategies for treatment of drug-resistant infections, both in the development of new agents, for example, less impacted by efflux or in targeting efflux directly with efflux inhibitors.
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Affiliation(s)
- Keith Poole
- Department of Microbiology & Immunology, Queen's University, Kingston, ON, Canada.
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14
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Kurupati P, Tan KSW, Kumarasinghe G, Poh CL. Inhibition of gene expression and growth by antisense peptide nucleic acids in a multiresistant beta-lactamase-producing Klebsiella pneumoniae strain. Antimicrob Agents Chemother 2006; 51:805-11. [PMID: 17158940 PMCID: PMC1803136 DOI: 10.1128/aac.00709-06] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Klebsiella pneumoniae causes common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance. The emergence and spread of beta-lactamase-producing K. pneumoniae strains highlight the need to develop new therapeutic strategies. In this study, we developed antisense peptide nucleic acids (PNAs) conjugated to the (KFF)(3)K peptide and investigated whether they could mediate gene-specific antisense effects in K. pneumoniae. No outer membrane permeabilization was observed with antisense PNAs when used alone. Antisense peptide-PNAs targeted at two essential genes, gyrA and ompA, were found to be growth inhibitory at concentrations of 20 muM and 40 muM, respectively. Mismatched antisense peptide-PNAs with sequence variations of the gyrA and ompA genes when used as controls were not growth inhibitory. Bactericidal effects exerted by peptide-anti-gyrA PNA and peptide-anti-ompA PNA on cells were observed within 6 h of treatment. The antisense peptide-PNAs specifically inhibited expression of DNA gyrase subunit A and OmpA from the respective targeted genes in a dose-dependent manner. Both antisense peptide-PNAs cured IMR90 cell cultures that were infected with K. pneumoniae (10(4) CFU) in a dose-dependent manner without any noticeable toxicity to the human cells.
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MESH Headings
- Antisense Elements (Genetics)/pharmacology
- Cells, Cultured
- Cephalosporins
- Chromosomes, Bacterial/drug effects
- Chromosomes, Bacterial/enzymology
- DNA, Bacterial/biosynthesis
- DNA, Bacterial/genetics
- Fibroblasts/metabolism
- Gene Expression Regulation, Bacterial/drug effects
- Gene Silencing/drug effects
- Genes, Reporter/drug effects
- Humans
- Indicators and Reagents
- Kinetics
- Klebsiella pneumoniae/drug effects
- Klebsiella pneumoniae/genetics
- Klebsiella pneumoniae/growth & development
- Lac Operon/genetics
- Peptide Nucleic Acids/pharmacology
- RNA, Bacterial/biosynthesis
- RNA, Bacterial/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- beta-Lactamases/biosynthesis
- beta-Lactamases/genetics
- beta-Lactamases/metabolism
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Affiliation(s)
- Prathiba Kurupati
- Department of Microbiology, Yong Loo Lin School of Medicine, National University of Singapore, Block MD4, 5 Science Drive 2, Singapore 117597, Singapore
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15
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Doménech-Sánchez A, Benedí VJ, Martínez-Martínez L, Albertí S. Evaluation of differential gene expression in susceptible and resistant clinical isolates of Klebsiella pneumoniae by DNA microarray analysis. Clin Microbiol Infect 2006; 12:936-40. [PMID: 16882305 DOI: 10.1111/j.1469-0691..01470.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
DNA microarray technology was used to evaluate differential gene expression in a susceptible Klebsiella pneumoniae isolate and a resistant clinical derivative. Nineteen genes were up-regulated in the resistant isolate when compared with the susceptible isolate. An ABC transporter-related gene, ycjV, was strongly over-expressed, suggesting the existence of a novel active efflux mechanism. Approximately half of the up-regulated genes coded for ribosomal proteins, or proteins involved in tRNA metabolism. Among 33 downregulated genes, almost one-third were related to nitrogen metabolism. A possible role of fitness in the development of antimicrobial resistance is suggested.
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Affiliation(s)
- A Doménech-Sánchez
- Departamento de Biología and Institut Universitari d'Investigació en Ciències de la Salut, Universidad de las Islas Baleares, Palma de Mallorca, Spain
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16
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Campos MA, Morey P, Bengoechea JA. Quinolones sensitize gram-negative bacteria to antimicrobial peptides. Antimicrob Agents Chemother 2006; 50:2361-7. [PMID: 16801413 PMCID: PMC1489791 DOI: 10.1128/aac.01437-05] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The treatment of infections caused by bacteria resistant to the vast majority of antibiotics is a challenge worldwide. Antimicrobial peptides (APs) make up the front line of defense in those areas exposed to microorganisms, and there is intensive research to explore their use as new antibacterial agents. On the other hand, it is known that subinhibitory concentrations of antibiotics affect the expression of numerous bacterial traits. In this work we evaluated whether treatment of bacteria with subinhibitory concentrations of quinolones may alter the sensitivity to APs. A 1-h treatment of Klebsiella pneumoniae with 0.25 x the MIC of ciprofloxacin rendered bacteria more sensitive to polymyxins B and E, human neutrophil defensin 1, and beta-defensin 1. Levofloxacin and nalidixic acid at 0.25 x the MICs also increased the sensitivity of K. pneumoniae to polymyxin B, whereas gentamicin and ceftazidime at 0.25 x the MICs did not have such an effect. Ciprofloxacin also increased the sensitivities of K. pneumoniae ciprofloxacin-resistant strains to polymyxin B. Two other pathogens, Pseudomonas aeruginosa and Haemophilus influenzae, also became more sensitive to polymyxins B and E after treatment with 0.25 x the MIC of ciprofloxacin. Incubation with ciprofloxacin did not alter the expression of the K. pneumoniae loci involved in resistance to APs. A 1-N-phenyl-naphthylamine assay showed that ciprofloxacin and levofloxacin increased the permeabilities of the K. pneumoniae and P. aeruginosa outer membranes, while divalent cations antagonized this action. Finally, we demonstrated that ciprofloxacin and levofloxacin increased the binding of APs to the outer membrane by using dansylated polymyxin B.
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Affiliation(s)
- Miguel A Campos
- Unidad de Investigación, Hospital Universitario Son Dureta, and Institut Universitari d'Investigacions en Ciències de la Salut (IUNICS), Palma de Mallorca, Spain
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17
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Doménech-Sánchez A, Javier Benedí V, Martínez-Martínez L, Albertí S. Evaluation of differential gene expression in susceptible and resistant clinical isolates of Klebsiella pneumoniae by DNA microarray analysis. Clin Microbiol Infect 2006. [DOI: 10.1111/j.1469-0691.2006.01470.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kurupati P, Teh BK, Kumarasinghe G, Poh CL. Identification of vaccine candidate antigens of an ESBL producingKlebsiella pneumoniae clinical strain by immunoproteome analysis. Proteomics 2006; 6:836-44. [PMID: 16372264 DOI: 10.1002/pmic.200500214] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Klebsiella pneumoniae is an opportunistic pathogen which causes pneumoniae, urinary tract infections and septicemia in immunocompromised patients. Hospital outbreaks of multidrug-resistant K. pneumoniae, especially those in neonatal wards, are often caused by strains producing the extended-spectrum-beta-lactamases (ESBLs). An immunoproteome based approach was developed to identify candidate antigens of K. pneumoniae for vaccine development. Sera from patients with acute K. pneumoniae infections (n = 55) and a control group of sera from healthy individuals (n = 15) were analyzed for reactivity by Western blot against ESBL K. pneumoniae outer membrane proteins separated by 2-DE. Twenty highly immunogenic protein spots were identified by immunoproteomic analysis. The immunogenic proteins that are most frequently recognized by positive K. pneumoniae sera were OmpA, OmpK36, FepA, OmpK17, OmpW, Colicin I receptor protein and three novel proteins. Two of the vaccine candidate genes, OmpA (Struve et al. Microbiology 2003, 149, 167-176) and FepA (Lai, Y. C. et al.. Infect Immun 2001, 69, 7140-7145), have recently been shown to be essential in colonization and infection in an in vivo mouse model. Hence, these two immunogenic proteins could serve as potential vaccine candidates.
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Affiliation(s)
- Prathiba Kurupati
- Department of Microbiology, National University of Singapore, Singapore
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19
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Miró E, Vergés C, García I, Mirelis B, Navarro F, Coll P, Prats G, Martínez-Martínez L. [Resistance to quinolones and beta-lactams in Salmonella enterica due to mutations in topoisomerase-encoding genes, altered cell permeability and expression of an active efflux system]. Enferm Infecc Microbiol Clin 2005; 22:204-11. [PMID: 15056435 DOI: 10.1016/s0213-005x(04)73067-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The mechanisms of resistance to fluoroquinolones and beta-lactams were studied in isolates of Salmonella enterica resistant to both antimicrobial groups, isolated over time from two patients treated with fluoroquinolones. METHODS The clonal relationships among the various strains was established by serotyping and pulsed-field gel electrophoresis. MICs for beta-lactams, quinolones, chloramphenicol and tetracycline were determined. Presence of beta-lactamases was ruled out by a colorimetric assay. Quinolone resistance-determining regions of the gyrA, gyrB, parC, and parE genes were sequenced, and the relevance of the mutations in these regions was evaluated by complementation assays. Outer membrane protein profiles, the effect of phenylalanyl-arginyl-naphthylamide (PAN, 20 mg/l) on the MICs of several quinolones, and norfloxacin accumulation in the absence and in the presence of a metabolic inhibitor were also determined. RESULTS The following mutations were found: gyrA (Asp87 --> Gly; Ser83 --> Phe; Asp87 --> Lys), gyrB (Ser463 --> Phe) and parC (Glu84 --> Gly). Altered outer membrane protein profiles, including decreased expression of a porin equivalent to OmpF from Escherichia coli was observed. Active efflux of norfloxacin was proved in both a clinical isolate and a mutant obtained in vitro. In the presence of PAN, nalidixic acid MICs decreased 4-32 times (except in one strain), pefloxacin MICs decreased 4-16 times for 5 out of 9 evaluated strains, and MICs of both norfloxacin and ciprofloxacin did not change or changed within a single dilution step. CONCLUSIONS Quinolone-resistance is the consequence of a combination of mutations in topoisomerase-encoding genes, altered permeability and active efflux. Altered permeability and active efflux would also contribute to decreased susceptibility to beta-lactams.
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Affiliation(s)
- Elisenda Miró
- Servicio de Microbiología, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
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20
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Tavío MM, Vila J, Perilli M, Casañas LT, Maciá L, Amicosante G, Jiménez de Anta MT. Enhanced active efflux, repression of porin synthesis and development of Mar phenotype by diazepam in two enterobacteria strains. J Med Microbiol 2004; 53:1119-1122. [PMID: 15496390 DOI: 10.1099/jmm.0.45613-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this work was to determine whether diazepam could induce the multiple antibiotic resistance (Mar) phenotype in Klebsiella pneumoniae and Escherichia coli strains. The Mar phenotype is characterized by decreased susceptibility to multiple antibiotics due to the loss of porins and/or increased expression of active efflux systems. The effect of subinhibitory concentrations of diazepam on the susceptibility of different antimicrobial agents, outer-membrane protein expression and norfloxacin intracellular accumulation was studied. The results revealed that diazepam concentrations equal or twice adult dosage induced the same Mar phenotype as two well known E. coli marRAB inducers, sodium salicylate and sodium benzoate. Susceptibility to norfloxacin in a K. pneumoniae clinical isolate and E. coli strain Ag100 decreased due to enhanced active efflux and loss of porin expression. A decreased susceptibility to chloramphenicol, tetracycline, nalidixic acid and β-lactam antibiotics was also observed. In conclusion, like sodium salicylate or sodium benzoate, diazepam may induce the Mar phenotype.
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Affiliation(s)
- María M Tavío
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - Jordi Vila
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - Mariagrazia Perilli
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - Lucía T Casañas
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - Laura Maciá
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - Gianfranco Amicosante
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
| | - María T Jiménez de Anta
- Microbiology, Department of Clinical Sciences, School of Medicine, University of Las Palmas de G. C., Dr. Pasteur, 35080 Las Palmas, Spain 2Department of Microbiology, Hospital Clinic, IDIBAPS, School of Medicine, University of Barcelona, Villarroel, 170, 08036 Barcelona, Spain 3Department of Science and Biomedical Technology, School of Medicine, University of L'Aquila, L'Aquila, Italy
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21
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Abstract
Multiresistance in Gram-negative pathogens, particularly Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter spp. and the Enterobacteriaceae, is a significant problem in medicine today. While multiple mechanisms often contribute to multiresistance, a broadly distributed family of three-component multidrug efflux systems is an increasingly recognised determinant of both intrinsic and acquired multiresistance in these organisms. Homologues of these efflux systems are also readily identifiable in the genome sequences of a wide range of Gram-negative organisms, pathogens and non-pathogens alike, where they probably promote efflux-mediated resistance to multiple antimicrobials. Significantly, these systems often accommodate biocides, raising the spectre of biocide-mediated selection of multiresistance in Gram-negative pathogens. While there is some debate as to the natural function of these efflux systems, only some of which are inducible by their antimicrobial substrates, their contribution to resistance in a variety of pathogens nonetheless makes them reasonable targets for therapeutic intervention. Indeed, given the incredible chemical diversity of substrates accommodated by these efflux systems, it is likely that many novel or yet to be discovered antimicrobials will themselves be efflux substrates and, as such, efflux inhibitors may become an important component of Gram-negative antimicrobial therapy.
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Affiliation(s)
- K Poole
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada K7L 3N6.
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22
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Chen FJ, Lauderdale TL, Ho M, Lo HJ. The roles of mutations in gyrA, parC, and ompK35 in fluoroquinolone resistance in Klebsiella pneumoniae. Microb Drug Resist 2003; 9:265-71. [PMID: 12959405 DOI: 10.1089/107662903322286472] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In a survey of 541 Klebsiella pneumoniae isolates from 44 hospitals in Taiwan, three distinct populations were identified by the disk diffusion method according to the disribution of zone diameters of ciprofloxacin. Isolates with resistant, reduced-susceptible, and susceptible to fluoroquinolone were defined as CIP zone diameters of < or = 15 mm, 16-26 mm, and > or = 27 mm, respectively. Thus, in addition to 38 (7%) resistant isolates, there were 30 (5.5%) reduced-susceptible isolates and 473 (87.5%) susceptible isolates. A total of 34 isolates consisting of nine resistant, 13 reduced-susceptible, and 12 susceptible isolates were assessed for point mutations in gyrA and parC and the outer membrane profiles. The susceptibility to fluoroquinolone of 13 reduced-susceptible isolates was not altered in the presence of carbonyl cyanide m-chlorophenylhydrazone, an efflux inhibitor, showing that efflux is not a major contributor to reduced susceptibility. In addition to single mutation in gyrA, OmpK35 porin loss can also be the first step for developing fluoroquinolone resistance. No strain possesses a parC mutation without the simultaneous presence of a gyrA mutation, suggesting that mutations in parC play a complementary role for higher-level of fluoroquinolone resistance and fluoroquinolone resistance is a multistep process.
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Affiliation(s)
- Feng-Jui Chen
- Division of Clinical Research, National Health Research Institutes, Taipei, Taiwan
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23
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Wagenlehner FME, Heisig P, Irtenkauf C, Notka F, Decker J, Lehn N, Linde H. Clinically significant borderline resistance of sequential clinical isolates of Klebsiella pneumoniae. Int J Antimicrob Agents 2003; 22:367-73. [PMID: 14522099 DOI: 10.1016/s0924-8579(03)00126-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Two sequential clinical isolates of Klebsiella pneumoniae (Kpn) were isolated from bronchoalveolar lavage fluid (Kpn#1) and sputum (Kpn#2) of a patient with pneumonia, complicated by anatomical and immunosuppressive problems due to Wegener's granulomatosis. Despite 4 weeks of systemic treatment with ciprofloxacin (CIP) Kpn#2 was isolated thereafter. A fluoroquinolone-resistant mutant (Kpn#1-SEL) was derived from Kpn#1 in vitro by selecting on agar plates supplemented with ofloxacin. Kpn#1, Kpn#1-SEL and Kpn#2 had an identical pattern in PFGE. CIP MICs were 0.25, 2 and 4 mg/l for Kpn#1, Kpn#2 and Kpn#1-SEL, respectively. Kpn ATCC 10031 (CIP MIC 0.002 mg/l) served as control. We analyzed mechanisms of fluoroquinolone resistance by determining antibiotic susceptibility, organic solvent tolerance, accumulation of fluoroquinolones, dominance testing with wild-type topoisomerase genes (gyrA/B, parC/E), sequencing of the quinolone resistance determining regions of gyrA/B, parC/E and marR and Northern blotting of marR and acrAB genes. Compared with Kpn ATCC 10031, elevated MICs to fluoroquinolones and unrelated antibiotics in Kpn#1 was presumably due to a primary efflux pump other than AcrAB and increased the CIP MIC 125-fold. Although Kpn#1 tested sensitive according to NCCLS breakpoints, the elevated CIP MIC of 0.25 mg/l presumably rendered this isolate clinically resistant and lead to therapeutic failure in this case. Further increase of MIC to fluoroquinolones in vivo and in vitro was distinct. Kpn#1-SEL, selected in vitro, acquired a GyrA target mutation, whereas in Kpn#2 no known resistance mechanism could be detected.
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Affiliation(s)
- F M E Wagenlehner
- Institute for Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany.
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24
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Doménech-Sánchez A, Martínez-Martínez L, Hernández-Allés S, del Carmen Conejo M, Pascual A, Tomás JM, Albertí S, Benedí VJ. Role of Klebsiella pneumoniae OmpK35 porin in antimicrobial resistance. Antimicrob Agents Chemother 2003; 47:3332-5. [PMID: 14506051 PMCID: PMC201126 DOI: 10.1128/aac.47.10.3332-3335.2003] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2003] [Revised: 04/21/2003] [Accepted: 07/12/2003] [Indexed: 11/20/2022] Open
Abstract
OmpK35 from Klebsiella pneumoniae is the homologue of Escherichia coli OmpF porin. Expression of OmpK35 in K. pneumoniae strain CSUB10R (lacking both OmpK35 and OmpK36) decreased the MICs of cephalosporins and meropenem > or = 128-fold and decreased the MICs of imipenem, ciprofloxacin, and chloramphenicol > or = 8-fold. MIC reductions by OmpK35 were 4 times (cefepime), 8 times (cefotetan, cefotaxime, and cefpirome), or 128 times (ceftazidime) higher than those caused by OmpK36, but the MICs were similar or 1 dilution lower for other evaluated agents.
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Affiliation(s)
- Antonio Doménech-Sánchez
- Laboratory of Microbiology, Department of Biology, University of the Balearic Island. IMEDEA (CSIC-UIB) Research Unit, University Hospital Son Dureta, Palma de Mallorca, Spain
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25
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Schneiders T, Amyes SGB, Levy SB. Role of AcrR and ramA in fluoroquinolone resistance in clinical Klebsiella pneumoniae isolates from Singapore. Antimicrob Agents Chemother 2003; 47:2831-7. [PMID: 12936981 PMCID: PMC182603 DOI: 10.1128/aac.47.9.2831-2837.2003] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The MICs of ciprofloxacin for 33 clinical isolates of K. pneumoniae resistant to extended-spectrum cephalosporins from three hospitals in Singapore ranged from 0.25 to >128 microg/ml. Nineteen of the isolates were fluoroquinolone resistant according to the NCCLS guidelines. Strains for which the ciprofloxacin MIC was >or=0.5 microg/ml harbored a mutation in DNA gyrase A (Ser83-->Tyr, Leu, or IIe), and some had a secondary Asp87-->Asn mutation. Isolates for which the MIC was 16 microg/ml possessed an additional alteration in ParC (Ser80-->IIe, Trp, or Arg). Tolerance of the organic solvent cyclohexane was observed in 10 of the 19 fluoroquinolone-resistant strains; 3 of these were also pentane tolerant. Five of the 10 organic solvent-tolerant isolates overexpressed AcrA and also showed deletions within the acrR gene. Complementation of the mutated acrR gene with the wild-type gene decreased AcrA levels and produced a two- to fourfold reduction in the fluoroquinolone MICs. None of the organic solvent-tolerant clinical isolates overexpressed another efflux-related gene, acrE. While marA and soxS were not overexpressed, another marA homologue, ramA, was overexpressed in 3 of 10 organic solvent-tolerant isolates. These findings indicate that multiple target and nontarget gene changes contribute to fluoroquinolone resistance in K. pneumoniae. Besides AcrR mutations, ramA overexpression (but not marA or soxS overexpression) was related to increased AcrAB efflux pump expression in this collection of isolates.
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Affiliation(s)
- T Schneiders
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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26
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Gruteke P, Goessens W, Van Gils J, Peerbooms P, Lemmens-Den Toom N, Van Santen-Verheuvel M, Van Belkum A, Verbrugh H. Patterns of resistance associated with integrons, the extended-spectrum beta-lactamase SHV-5 gene, and a multidrug efflux pump of Klebsiella pneumoniae causing a nosocomial outbreak. J Clin Microbiol 2003; 41:1161-6. [PMID: 12624046 PMCID: PMC150252 DOI: 10.1128/jcm.41.3.1161-1166.2003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiresistant Klebsiella pneumoniae caused a nosocomial outbreak. Resistance patterns of the presumed outbreak isolates varied among and within patients. In order to control the outbreak, screening for extended-spectrum beta-lactamase (ESBL)-producing K. pneumoniae was commenced. A number of susceptible K. pneumoniae strains were stored to serve as controls in genetic strain typing. Typing by pulsed-field gel electrophoresis proved the clonality of the strains in the recognized outbreak patients. Typing of the control strains by pulsed-field gel electrophoresis showed that at least one patient had been missed by the ESBL screening procedure. Further genetic typing confirmed the presence of the SHV-5 ESBL gene in all but one of the outbreak strains. Variable presence of integrons that carried the aminoglycoside resistance genes aadB and aadA2 was found. A gyrA mutation in codon 83 was present in all outbreak strains tested, despite considerable differences in ciprofloxacin MICs. The MICs of ciprofloxacin and the chemically unrelated drug cefoxitin were correlated (r = 0.86, P < 0.01) and were compatible with the overexpression of an efflux pump in a subset of the outbreak strains. We conclude that outbreak strains that express an ESBL gene only at a low level may pass unnoticed in a screening procedure, when the laboratory is unaware of variable ESBL expression. In this particular outbreak, screening for strains for which ciprofloxacin MICs were > or =0.25 micro g/ml would in retrospect have been the most sensitive method for detection of the K. pneumoniae outbreak strain.
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Affiliation(s)
- Paul Gruteke
- Municipal Public Health Laboratory, Amsterdam. Zuiderzee Hospital, Lelystad, The Netherlands.
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27
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Martínez-Martínez L, Pascual A, Conejo MDC, García I, Joyanes P, Doménech-Sánchez A, Benedí VJ. Energy-dependent accumulation of norfloxacin and porin expression in clinical isolates of Klebsiella pneumoniae and relationship to extended-spectrum beta-lactamase production. Antimicrob Agents Chemother 2002; 46:3926-32. [PMID: 12435697 PMCID: PMC132737 DOI: 10.1128/aac.46.12.3926-3932.2002] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The relationships between porin deficiency, active efflux of fluoroquinolones, and extended-spectrum beta-lactamase (ESBL) production were determined for 53 clinical isolates of Klebsiella pneumoniae. Thirty-two ESBL-positive strains (including 22 strains expressing porins and 10 strains lacking porins) and 21 ESBL-negative strains were evaluated. Active efflux of norfloxacin was defined as a >/=50% increase in the accumulation of norfloxacin in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) in comparison with the corresponding basal value in the absence of CCCP. The quinolone resistance-determining regions of both gyrA and parC from 13 strains, representing all isolates with different porin profiles and with or without active efflux, were determined. Porin loss was significantly more common among ESBL-positive strains (10 of 32 [31.2%]) than among ESBL-negative strains (0 of 2 [0%]) (P < 0.01). Active efflux was observed in 7 of 10 (70%) strains lacking porins and in 4 of 43 (9.3%) strains producing porins (P < 0.001). The 11 strains showing active efflux corresponded to 3 of 21 (14.3%) ESBL-negative strains and 8 of 32 (25.5%) ESBL-positive strains (P > 0.05). Basal values of norfloxacin accumulation were higher in strains lacking active efflux than in those that had this mechanism (P < 0.05). In the absence of topoisomerase changes, the contribution of either porin loss or active efflux to fluoroquinolone resistance in K. pneumoniae was negligible. It is concluded that among K. pneumoniae strains of clinical origin, porin loss was observed only in those producing ESBL, and that a significant number of porin-deficient strains also expressed active efflux of norfloxacin. In terms of fluoroquinolone resistance, both mechanisms are significant only in the presence of topoisomerase modifications.
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28
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Linde HJ, Notka F, Irtenkauf C, Decker J, Wild J, Niller HH, Heisig P, Lehn N. Increase in MICs of ciprofloxacin in vivo in two closely related clinical isolates of Enterobacter cloacae. J Antimicrob Chemother 2002; 49:625-30. [PMID: 11909836 DOI: 10.1093/jac/49.4.625] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mechanisms of fluoroquinolone resistance in two isolates of Enterobacter cloacae, Ecl#1 and Ecl#2, from the same patient and with identical pulsed-field gel electrophoresis patterns, have been analysed. MICs of ciprofloxacin were 0.25 and 1 mg/L for Ecl#1 and Ecl#2, respectively. Ecl#2 was also more resistant to chloramphenicol and organic solvents. The quinolone resistance determining regions of gyrA/B and parC/E, and the marORA and acrB genes, were sequenced. Expression of marR, acrB, soxS, robA, ramA and fis was analysed by northern blotting. The activity of a 90 bp E. cloacae mar promoter fragment was examined with the reporter plasmid pIGJ-1mar. Sequencing the gyrAB and parCE genes revealed a single amino acid substitution in GyrA (corresponding to position 83 in GyrA of Escherichia coli) in Ecl#1 and Ecl#2 (Phe83) compared with reference strain E. cloacae DSMZ 3264 (Thr83). Ecl#2 accumulated significantly less norfloxacin and displayed higher levels of expression of marR and acrB than Exl#1, indicative of greater fluoroquinolone efflux activity. Sequencing gyrB, parC/E and marORA, and northern blotting of robA, ramA and fis, did not reveal any further differences between the two strains. No homologue of soxRS was detected in E. cloacae. Expression of GFP from pIGJ1-mar in Ecl#2 was higher than in Ecl#1. In these two closely related clinical isolates of E. cloacae, a target mutation in GyrA (Ecl#1 and Ecl#2) and increased fluoroquinolone efflux by AcrAB (Ecl#2) contribute to the resistance phenotypes, corroborating findings in vitro and in vivo about the sequential development of fluoroquinolone resistance.
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Affiliation(s)
- Hans-Jörg Linde
- Institute for Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany.
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29
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Berlanga M, Vázquez JL, Hernandez-Borrell J, Montero MT, Viñas M. Evidence of an efflux pump in Serratia marcescens. Microb Drug Resist 2001; 6:111-7. [PMID: 10990265 DOI: 10.1089/107662900419410] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spontaneous mutants resistant to fluoroquinolones were obtained by exposing Serratia marcescens NIMA (wild-type strain) to increasing concentrations of ciprofloxacin both in liquid and on solid media. Frequencies of mutation ranged from 10(-7) to 10(-9). Active expulsion of antibiotic was explored as a possible mechanism of resistance in mutants as well as changes in topoisomerase target genes. The role of extrusion mechanisms in determining the emergence of multidrug-resistant bacteria was also examined. Mutants resistant to high concentrations of fluoroquinolones had a single mutation in their gyrA QRDR sequences, whereas the moderate resistance in the rest of mutants was due to extrusion of the drug.
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Affiliation(s)
- M Berlanga
- Microbiology Unit, University of Barcelona, Spain
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30
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Poole K. Efflux-mediated resistance to fluoroquinolones in gram-negative bacteria. Antimicrob Agents Chemother 2000; 44:2233-41. [PMID: 10952561 PMCID: PMC90051 DOI: 10.1128/aac.44.9.2233-2241.2000] [Citation(s) in RCA: 266] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- K Poole
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada.
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31
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Chevalier J, Pagès JM, Eyraud A, Malléa M. Membrane permeability modifications are involved in antibiotic resistance in Klebsiella pneumoniae. Biochem Biophys Res Commun 2000; 274:496-9. [PMID: 10913366 DOI: 10.1006/bbrc.2000.3159] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two Klebsiella pneumoniae strains selected according to their high cross-resistance pattern to cephalosporins were characterized by (i) outer membrane protein content such as OmpA or nonspecific porins, (ii) MICs of various cephalosporins and unrelated antibiotics, (iii) beta-lactamase production, and (iv) active efflux of fluoroquinolones. An association of porin deficiency and beta-lactamase production induced a noticeable cephalosporin resistance. In addition to these mechanisms, the presence of an active efflux participating in high-level fluoroquinolone resistance was identified in one strain. The decrease of antibiotic uptake associated with efflux explains the Klebsiella adaptation against the drugs present in the environment.
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Affiliation(s)
- J Chevalier
- Faculté de Médecine, CJF 9606 INSERM, Université de la Méditerranée, 27 Boulevard Jean Moulin, Marseille Cedex 05, 13385, France
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32
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Abstract
Mechanisms of bacterial resistance to fluoroquinolones fall into two principal categories, alterations in drug target enzymes and alterations that limit permeation of drug to the target, both resulting from chromosomal mutations. No specific resistance mechanisms of quinolone degradation or modification have been found. The target enzymes, DNA gyrase and topoisomerase IV are most commonly altered in domains near the enzyme active sites and in some cases reduced drug binding affinity has been demonstrated. Drug permeation is altered by mutations that increase expression of endogenous multidrug efflux pumps, alter outer membrane diffusion channels, or both. Recently a new plasmid-mediated resistance of an as yet undefined mechanism was found in clinical isolates of Klebsiella pneumoniae. Copyright 1999 Harcourt Publishers Ltd.
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Affiliation(s)
- David C. Hooper
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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33
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Lark RL, Chenoweth C. Antimicrobial resistance in community-acquired respiratory tract pathogens. COMPREHENSIVE THERAPY 1999; 25:20-9. [PMID: 9987589 DOI: 10.1007/bf02889831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Antimicrobial resistance among common respiratory pathogens has become a significant problem. However, there remain multiple treatment options, including the newer macrolides, third-generation cephalosporins, beta-lactam/beta-lactamase inhibitor antibiotics, and the newer fluoroquinolones.
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Affiliation(s)
- R L Lark
- Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, USA
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