Increased resistance to multiple drugs by introduction of the Enterobacter cloacae romA gene into OmpF porin-deficient mutants of Escherichia coli K-12

Komatsu, Takayuki; Ohta, Michio; Kido, Nobuo; Arakawa, Yoshichika; Ito, Hideo; Kato, Naoya

doi:10.1128/aac.35.10.2155

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…Kp342 encodes ramA (KPK_4028), a gene previously identified in K. pneumoniae that confers resistance to chloramphenicol, tetracycline, nalidixic acid, ampicillin, norfloxacin, trimethoprim and puromycin A when expressed in E. coli K12 [73] . Immediately upstream of this gene is romA (KPK_4029), which was originally isolated from Enterobacter cloacae as a gene that when expressed in E. coli , caused reduced expression of outer membrane proteins, resulting in a multiple drug resistance phenotype (quinolones, beta-lactams, chloramphenicol, and tetracycline) [74] that is independent of OmpF [75] . This gene has recently been shown to be adjacent to ramA in K. pneumoniae G340 during the sequencing of a tigecycline susceptible transposon mutant clone in ramA [76] .…”

Section: Resultsmentioning

confidence: 99%

Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice

et al. 2008

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We report here the sequencing and analysis of the genome of the nitrogen-fixing endophyte, Klebsiella pneumoniae 342. Although K. pneumoniae 342 is a member of the enteric bacteria, it serves as a model for studies of endophytic, plant-bacterial associations due to its efficient colonization of plant tissues (including maize and wheat, two of the most important crops in the world), while maintaining a mutualistic relationship that encompasses supplying organic nitrogen to the host plant. Genomic analysis examined K. pneumoniae 342 for the presence of previously identified genes from other bacteria involved in colonization of, or growth in, plants. From this set, approximately one-third were identified in K. pneumoniae 342, suggesting additional factors most likely contribute to its endophytic lifestyle. Comparative genome analyses were used to provide new insights into this question. Results included the identification of metabolic pathways and other features devoted to processing plant-derived cellulosic and aromatic compounds, and a robust complement of transport genes (15.4%), one of the highest percentages in bacterial genomes sequenced. Although virulence and antibiotic resistance genes were predicted, experiments conducted using mouse models showed pathogenicity to be attenuated in this strain. Comparative genomic analyses with the presumed human pathogen K. pneumoniae MGH78578 revealed that MGH78578 apparently cannot fix nitrogen, and the distribution of genes essential to surface attachment, secretion, transport, and regulation and signaling varied between each genome, which may indicate critical divergences between the strains that influence their preferred host ranges and lifestyles (endophytic plant associations for K. pneumoniae 342 and presumably human pathogenesis for MGH78578). Little genome information is available concerning endophytic bacteria. The K. pneumoniae 342 genome will drive new research into this less-understood, but important category of bacterial-plant host relationships, which could ultimately enhance growth and nutrition of important agricultural crops and development of plant-derived products and biofuels.

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Section: Resultsmentioning

confidence: 99%

Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice

et al. 2008

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“…Komatsu et al (11) reported that introduction of the romA4 gene of Enterobacter cloacae into Escherichia coli resulted in resistance to ampicillin, cephems, quinolones, tetracyclines, and chloramphenicol, with the concomitant appearance of a new outer membrane protein. Nicas and Hancock (13) also reported that overexpression of outer membrane protein Hi in P. aeruginosa resulted in decreased susceptibilities to gentamicin, polymyxin B, and EDTA.…”

Section: Resultsmentioning

confidence: 99%

Cross-resistance to meropenem, cephems, and quinolones in Pseudomonas aeruginosa

Masuda¹,

Ohya²

1992

Antimicrob Agents Chemother

205

165

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Multiple-drug-resistant mutants were isolated from Pseudomonas aeruginosa PAO1 on agar plates containing ofloxacin and cefsulodin. These mutants were four to eight times more resistant to meropenem, cephems, carbenicillin, quinolones, tetracycline, and chloramphenicol than the parent strain was. In contrast, these mutants showed no significant changes in their susceptibilities to all carbapenems except meropenem. In these mutants, the amounts of an outer membrane protein with an apparent molecular weight of 49,000 (designated OprM) were increased compared with the amount in PA01. Multiple-drug-resistant mutants of this type were also isolated from PAO1 on agar plates containing meropenem. Approximately 5% of clinical isolates showed cross-resistance to meropenem, cephems, and quinolones, concomitant with overproduction of OprM. Moreover, these two phenotypes, i.e., multiple-drug resistance and overproduction of OprM, were cotransferable by transduction. These data suggest that overproduction of OprM is associated with cross-resistance to meropenem, cephems, and quinolones in P. aeruginosa. The ofloxacin-cefsulodin-resistant mutant required higher concentrations of meropenem to induce 13-lactamase than PA01 did, indicating the possibility that this mutation involves decreased outer membrane permeability to meropenem.

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“…RamA is thought to form an operon with a gene specifying the outer membrane protein RomA. RamA acts as a transcriptional activator, while RomA is a putative channel-forming protein (7,14) somehow involved in the resistance phenotype. The role of ramA in the antibiotic resistance phenotype of clinical strains has not been described.…”

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confidence: 99%

Role of AcrR and RamA in Fluoroquinolone Resistance in Clinical Klebsiella pneumoniae Isolates from Singapore

Schneiders¹,

Amyes

Levy

2003

Antimicrob Agents Chemother

140

126

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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 g/ml. Nineteen of the isolates were fluoroquinolone resistant according to the NCCLS guidelines. Strains for which the ciprofloxacin MIC was >0.5 g/ml harbored a mutation in DNA gyrase A (Ser833Tyr, Leu, or IIe), and some had a secondary Asp873Asn mutation. Isolates for which the MIC was 16 g/ml possessed an additional alteration in ParC (Ser803IIe, 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 effluxrelated 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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Increased resistance to multiple drugs by introduction of the Enterobacter cloacae romA gene into OmpF porin-deficient mutants of Escherichia coli K-12

Cited by 9 publications

References 28 publications

Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice

Complete Genome Sequence of the N2-Fixing Broad Host Range Endophyte Klebsiella pneumoniae 342 and Virulence Predictions Verified in Mice

Cross-resistance to meropenem, cephems, and quinolones in Pseudomonas aeruginosa

Role of AcrR and RamA in Fluoroquinolone Resistance in Clinical Klebsiella pneumoniae Isolates from Singapore

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