Characterization of the Extended-Spectrum β-Lactamase Reference Strain,
            <i>Klebsiella pneumoniae</i>
            K6 (ATCC 700603), Which Produces the Novel Enzyme SHV-18

Rasheed, J. Kamile; Anderson, Gregory J.; Yigit, Hesna; Queenan, Anne Marie; Doménech-Sánchez, Antonio; Swenson, Jana M.; Biddle, James W.; Ferraro, Mary Jane; Jacoby, George A.; Tenover, Fred C.

doi:10.1128/aac.44.9.2382-2388.2000

Cited by 119 publications

(91 citation statements)

References 50 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Interestingly, a recent study reported by Doménech-Sanchez et al (12) described the incidence of OmpK35 and OmpK36 expression on the K. pneumoniae susceptibility towards various antibiotics. Similar observations have been previously reported in K. pneumoniae isolates and generated an interesting debate concerning the selectivity of OmpK35 (10,25,27). We show here that in E. aerogenes, the activities of imipenem and cefepime, two zwitterionic molecules, are only weakly affected compared to large negatively charged drugs, and similar observations were reported with OmpK35 and OmpK36 (12,20,25).…”

Section: Discussionsupporting

confidence: 76%

“…Similar observations have been previously reported in K. pneumoniae isolates and generated an interesting debate concerning the selectivity of OmpK35 (10,25,27). We show here that in E. aerogenes, the activities of imipenem and cefepime, two zwitterionic molecules, are only weakly affected compared to large negatively charged drugs, and similar observations were reported with OmpK35 and OmpK36 (12,20,25). Interestingly, an S residue is located in the PhoE eyelet and has been reported to be involved in the rate of uptake of large negatively charged cephalosporins (29).…”

Section: Discussionsupporting

confidence: 74%

See 1 more Smart Citation

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Bornet

Saint

Fetnaci

et al. 2004

Antimicrob Agents Chemother

View full text Add to dashboard Cite

In Enterobacter aerogenes, ␤-lactam resistance often involves a decrease in outer membrane permeability induced by modifications of porin synthesis. In ATCC 15038 strain, we observed a different pattern of porin production associated with a variable antibiotic susceptibility. We purified Omp35, which is expressed under conditions of low osmolality and analyzed its pore-forming properties in artificial membranes. This porin was found to be an OmpF-like protein with high conductance values. It showed a noticeably higher conductance compared to Omp36 and a specific location of WNYT residues in the L3 loop. The importance of the constriction region in the porin function suggests that this organization is involved in the level of susceptibility to negative large cephalosporins such as ceftriaxone by bacteria producing the Omp35 porin subfamily.The bacterial porins are major outer membrane proteins that form water-filled channels, allowing the diffusion across the outer membrane of small polar molecules, amino acids, and nutrients (14,18,23). General nonspecific porins, such as OmpF and OmpC from Escherichia coli, form homotrimers in the outer membrane. These porin trimers are constituted by large ␤-barrel monomer subunits which are constricted about halfway through the membrane by an internal loop, loop 3 (L3) (18). Resolution of the three-dimensional structure of the E. coli OmpF and Klebsiella pneumoniae OmpK36 has led to identification of the functional domains of the enterobacterial channels (5,8,13,17).Enterobacter aerogenes is one of the most frequently described gram-negative pathogens responsible for nosocomial respiratory tract infections in France and Belgium (2, 6, 10). This bacterial pathogen harbors a variety of antibiotic resistance mechanisms (7,9,19,24,30). Among them, the modification of outer membrane permeability, a porin deficiency associated with the expression of cephalosporinase activity, is frequently detected in clinical resistant isolates (7,19). We recently isolated a strain with an unusual porin phenotype: this EA3 strain synthesized a mutated Omp36 porin containing a G112D substitution in the L3 domain (19). Despite this prominent role of porins in drug susceptibility, only one porin, Omp36, is today functionally characterized in E. aerogenes (19).The aim of this work was to investigate the structural and functional properties of the second major pore-forming protein produced by the E. aerogenes strain. The sequence and the channel properties of the new porin Omp35 were determined and agree with the biological differences concerning the ␤-lactam susceptibility, observed between the bacteria producing either Omp35 or Omp36. MATERIALS AND METHODSBacterial strains, growth conditions, and antibiotic susceptibility tests. The E. aerogenes ATCC 15038 strain was used as the standard strain. E. aerogenes EAEP289 is a Kan s derivative of the previously described clinical strain EA27 (24). Bacteria were routinely grown in Luria-Bertani (LB) medium or nutrient broth (NB). For the determination of MI...

show abstract

Section: Discussionsupporting

confidence: 76%

Section: Discussionsupporting

confidence: 74%

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Bornet

Saint

Fetnaci

et al. 2004

Antimicrob Agents Chemother

View full text Add to dashboard Cite

show abstract

“…Another important finding was the observation that the extracts were effective in inhibiting the growth of extended-spectrum beta-lactamase producers, such as K.pneumoniae (ATCC 700503) and E. coli (ATCC 51446) [66] [67]. The three extracts tested were effective against K. pneumoniae (ATCC 700503), and EEF and EEL were effective against E. coli (ATCC 51446).…”

Section: Antimicrobial Activitymentioning

confidence: 99%

Antimicrobial and Antioxidant Activity of <i>Anacardium occidentale</i> L. Flowers in Comparison to Bark and Leaves Extracts

Silva¹,

Libério²,

Amaral³

et al. 2016

JBM

View full text Add to dashboard Cite

Anacardium occidentale L., Anacardiaceae, is frequently used to treat infections. We evaluated the antimicrobial and antioxidant activity of extracts obtained from aerial parts of the plant in comparison with the extract prepared with the flowers. Ethanol extracts of the leaves (EEL), stem bark (EEB), and flowers (EEF) were prepared separately. The antimicrobial activity was evaluated by agar diffusion and broth dilution methods. The minimum bactericidal and fungicidal concentrations were determined against: Streptococcus mutans, Lactobacillus acidophilus, Staphylococcus aureus, MRSA, Enterococcus faecalis, Streptococcus pyogenes, Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Helicobacter pylori, Salmonella choleraesuis, Candida albicans, and Candida tropicalis. The antioxidant activity of the extracts was evaluated based on their scavenger capacity of 2,2-diphenyl-1-picrylhydrazyle. The phytochemical profile was analyzed by colorimetric methods and by HPLC with UV detection. All extracts exhibited antioxidant and antimicrobial activity. Although, the EEF was the most effective since it inhibited the growth of all 14 microorganisms tested. Anacardic and galic acids were identified in all extracts as well phenolic compounds, triterpenes, flavones and xanthones. In conclusion, the extracts obtained from the aerial parts of A. occidentale, mainly the extract of flowers that was the most effective, are rich in bioactive metabolites that exert a potent antioxidant and antimicrobial effect. Taken together, the results indicate an important biotechnological potential of A. occidentale as a * Corresponding author. R. A. da Silva et al. 88source of compounds with broad-spectrum antimicrobial and of antioxidant activity to be used in the food and cosmetics industry.

show abstract

“…K. pneumoniae ATCC 13883 (22) and E. coli ATCC 25922 (23) were used as controls for porin expression.…”

Section: Methodsmentioning

confidence: 99%

Predictability of Phenotype in Relation to Common β-Lactam Resistance Mechanisms in Escherichia coli and Klebsiella pneumoniae

et al. 2016

View full text Add to dashboard Cite

cThe minimal concentration of antibiotic required to inhibit the growth of different isolates of a given species with no acquired resistance mechanisms has a normal distribution. We have previously shown that the presence or absence of transmissible antibiotic resistance genes has excellent predictive power for phenotype. In this study, we analyzed the distribution of six ␤-lactam antibiotic susceptibility phenotypes associated with commonly acquired resistance genes in Enterobacteriaceae in Sydney, Australia. Escherichia coli (n ‫؍‬ 200) and Klebsiella pneumoniae (n ‫؍‬ 178) clinical isolates, with relevant transmissible resistance genes (bla TEM , n ‫؍‬ 33; plasmid AmpC, n ‫؍‬ 69; extended-spectrum ␤-lactamase [ESBL], n ‫؍‬ 116; and carbapenemase, n ‫؍‬ 100), were characterized. A group of 60 isolates with no phenotypic resistance to any antibiotics tested and carrying none of the important ␤-lactamase genes served as comparators. The MICs for all drug-bacterium combinations had a normal distribution, varying only in the presence of additional genes relevant to the phenotype or, for ertapenem resistance in K. pneumoniae, with a loss or change in the outer membrane porin protein OmpK36. We demonstrated mutations in ompK36 or absence of OmpK36 in all isolates in which reduced susceptibility to ertapenem (MIC, >1 mg/liter) was evident. Ertapenem nonsusceptibility in K. pneumoniae was most common in the context of an OmpK36 variant with an ESBL or AmpC gene. Surveillance strategies to define appropriate antimicrobial therapies should include genotype-phenotype relationships for all major transmissible resistance genes and the characterization of mutations in relevant porins in organisms, like K. pneumoniae. E scherichia coli and Klebsiella pneumoniae are among the most important pathogens in community and hospital settings, and their increasing resistance to extended-spectrum (third-and fourth-generation) cephalosporin and carbapenem antibiotics is a major health threat. In Gram-negative bacteria, such as these, a variety of mechanisms may confer ␤-lactam resistance (1), but the spread of transmissible genes encoding extended-spectrum ␤-lactamases (ESBLs) (2), plasmid-mediated AmpC ␤-lactamases (pAmpCs) (3), and carbapenemases (4) is particularly significant. Carbapenems have been the antibiotics of choice for treating ESBLs and other multidrug-resistant strains, but carbapenem resistance is increasingly common (5). This is mostly attributed to the production of specific carbapenemases (6), but the expression of AmpC or ESBL enzymes in isolates with altered outer membrane porins is also associated with decreased susceptibility to carbapenems (7-9). Mutations in major outer membrane porins may be required for clinically relevant carbapenem resistance in K. pneumoniae isolates expressing carbapenemases, such as KPC and OXA-48-like enzymes, which rarely elicit clinically important antibiotic resistance in E. coli (6).The clinical definitions of antibiotic susceptibility are developed by the collection and analysis of...

show abstract

Characterization of the Extended-Spectrum β-Lactamase Reference Strain, Klebsiella pneumoniae K6 (ATCC 700603), Which Produces the Novel Enzyme SHV-18

Cited by 119 publications

References 50 publications

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Antimicrobial and Antioxidant Activity of <i>Anacardium occidentale</i> L. Flowers in Comparison to Bark and Leaves Extracts

Predictability of Phenotype in Relation to Common β-Lactam Resistance Mechanisms in Escherichia coli and Klebsiella pneumoniae

Contact Info

Product

Resources

About

Characterization of the Extended-Spectrum β-Lactamase Reference Strain, Klebsiella pneumoniae K6 (ATCC 700603), Which Produces the Novel Enzyme SHV-18

Cited by 119 publications

References 50 publications

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Omp35, a New Enterobacter aerogenes Porin Involved in Selective Susceptibility to Cephalosporins

Antimicrobial and Antioxidant Activity of &lt;i&gt;Anacardium occidentale&lt;/i&gt; L. Flowers in Comparison to Bark and Leaves Extracts

Predictability of Phenotype in Relation to Common β-Lactam Resistance Mechanisms in Escherichia coli and Klebsiella pneumoniae

Contact Info

Product

Resources

About

Antimicrobial and Antioxidant Activity of <i>Anacardium occidentale</i> L. Flowers in Comparison to Bark and Leaves Extracts