Enzymatic Modification of Aminoglycoside Antibiotics: a New 3-
            <i>N</i>
            -Acetylating Enzyme from a
            <i>Pseudomonas aeruginosa</i>
            Isolate

Biddlecome, S.; Haas, Michael J.; Davies, Julian; Miller, George H.; Rane, D. F.; Daniels, Peter J. L.

doi:10.1128/aac.9.6.951

Cited by 48 publications

(25 citation statements)

References 8 publications

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“…Acetylation of aminoglycosides can occur at the 1, 3, 6Ј, and 2Ј amino groups and involves virtually all medically useful compounds (e.g., gentamicin, tobramycin, netilmicin, and amikacin). Enzymes that modify the 3 position (3-N-aminoglycoside acetyltransferases [AAC(3)]) (11) and the 6Ј position (6Ј-N-aminoglycoside acetyltransferases [AAC(6Ј)]) (52, 172) were discovered early in P. aeruginosa and remain the most common acetyltransferases and, with ANT(2Љ) (see below), the most common enzymes providing for aminoglycoside resistance in this organism (19, 32, 37, 74, 99-101, 114, 127, 146, 150) (Table 2). The AAC (3)-I family, of which three variants (Ia [154,169], Ib [142], and Ic [125]) have been described in P. aeruginosa, is a common determinant of gentamicin resistance in this organism (3,31,32,114,142,143,150).…”

Section: Modifying Enzymesmentioning

confidence: 99%

Aminoglycoside Resistance inPseudomonas aeruginosa

Poole

2005

Antimicrob Agents Chemother

411

322

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Section: Modifying Enzymesmentioning

confidence: 99%

Aminoglycoside Resistance inPseudomonas aeruginosa

Poole

2005

Antimicrob Agents Chemother

411

322

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“…Enzymatic modification of aminoglycosides does not necessarily confer resistance to the drugs (1,3,4,10). We describe a clinical isolate, Serratia marcescens 75, which was highly susceptible to netilmicin and yet had a high level of aminoglycoside 2"-O-nucleotidyltransferase [ANT(2")] activity for netilmicin when assayed with excess aminoglycoside substrate.…”

mentioning

confidence: 99%

“…Several investigators have recognized that aminoglycosidemodifying activity, when assayed with excess aminoglycoside substrate, does not necessarily correlate with levels of resistance to the various aminoglycosides (1,4,10). Our findings of a low MIC of netilmicin despite high ANT(2") activity in S. marcescens 75 confirm this.…”

mentioning

confidence: 99%

Correlation of aminoglycoside resistance with the KmS and Vmax/Km ratios of enzymatic modification of aminoglycosides by 2''-O-nucleotidyltransferase

DeHertogh¹,

Lerner²

1985

Antimicrob Agents Chemother

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A clinical isolate, Serrafia marcescens 75, was found to be susceptible to netilmicin and yet had a high level of aminoglycoside 2"-O-nucleotidyltransferase activity for netilmicin. Kinetic studies of the partially purified enzyme revealed substrate inhibition for gentamicin and tobramycin at concentrations greater than 10-2 mM, but this was not observed for netilmicin. The MICs of the aminoglycosides tested exhibited a good inverse correlation with the K,. values for the enzyme and a direct correlation with the V,..1/K, ratios of the enzyme.Enzymatic modification of aminoglycosides does not necessarily confer resistance to the drugs (1, 3, 4, 10). We describe a clinical isolate, Serratia marcescens 75, which was highly susceptible to netilmicin and yet had a high level of aminoglycoside 2"-O-nucleotidyltransferase [ANT(2")] activity for netilmicin when assayed with excess aminoglycoside substrate. We examined the relationship between the MICs of netilmicin, tobramycin, and gentamicin and the kinetic parameters of the ANT(2') enzyme which modified each of these aminoglycosides.S. marcescens 75 was tested for susceptibility to aminoglycosides by an agar dilution method (7). Inocula of 104 CFU of cells grown overnight in brain heart infusion broth (BBL Microbiology Systems, Cockeysville, Md.) were applied with a pronged replicator (7) onto Mueller-Hinton agar (BBL) containing the test antibiotics in twofold dilutions. The strain was highly resistant to gentamicin and tobramycin, but susceptible to netilmicin (Table 1).Sonic extracts of S. marcescens 75 were prepared for the assay of aminoglycoside-modifying activity as previously described (9). Aminoglycoside-modifying activity was assayed by adsorption of the radioactive product onto phosphocellulose filter disks (Whatman P-81) by the method of Haas and Dowding (5). For the adenylylating assay, the final concentrations of reagents were as follows: 0.033 M Tris-hydrochloride, pH 7.8; 7.5 mM MgCl2; 2.5 mM dithiothreitol; tobramycin and yet did not confer resistance to netilmicin, even in another genetic background, we transferred resistance to tobramycin into Escherichia coli JSRO-N, a plasmidfree, nalidixic acid-resistant recipient. Transconjugants were selected with a frequency of 5 x 10-6 per donor cell on Mueller-Hinton agar containing tobramycin at 12.5 ,ug/ml and nalidixic acid as the counterselecting agent at 25 ,ug/ml. The MICs of gentamicin, tobramycin, and netilmicin were 50, 50, and 1.56 ,ug/ml, respectively. Sonic extracts from two transconjugants chosen for study had adenylylating activity for gentamicin, tobramycin, netilmicin, and kanamycin at ca. 50% the level of the activity from the donor strain. Again, there was negligible acetylating or phosphorylating activity.An 18-liter culture of S. marcescens 75 grown in brain heart infusion broth containing 15 ,ug of gentamicin per ml was incubated with agitation at 37°C until the optical density at 600 nm was 1.5. The cells were harvested, washed twice with 0.15 M NaCl, and centrifuged again. The final pe...

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“…CAB12939) (15,16,21), which is a member of the acetyltransferase family in B. subtilis. The enzyme N-acetyltransferase catalyzes the transfer of an acetyl group from acetyl coenzyme A (acetyl-CoA) to glucosamine 6-phosphate, the precursor of N-acetylglucosamine, a constituent of the peptidoglycan cell wall of Gram-positive bacteria (21,22). The thick peptidoglycan shell of endospores is known as the spore cortex and aids in survival during dormancy (23).…”

Section: Discussionmentioning

confidence: 99%

Geobacillus thermoglucosidasius Endospores Function as Nuclei for the Formation of Single Calcite Crystals

Murai

Yoshida

2013

Appl Environ Microbiol

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Geobacillus thermoglucosidasius colonies were placed on an agar hydrogel containing acetate, calcium ions, and magnesium ions, resulting in the formation of single calcite crystals (calcites) within and peripheral to the plating area or parent colony. Microscopic observation of purified calcites placed on the surface of soybean casein digest (SCD) nutrient medium revealed interior crevices from which bacterial colonies originated. Calcites formed on the gel contained [ Biomineralization is defined as the synthesis of inorganic crystalline or amorphous mineral-like materials by living organisms. Bacteria are capable of forming inorganic crystals either intracellularly (1) or extracellularly (2). Magnetic bacteria migrate along the lines of the earth's magnetic field and synthesize intracellular particles of magnetite that are aligned in a chain-like fashion and enveloped by a membrane (3, 4). The use of bacterial magnetic particles in biomedical applications is increasing because they are easy to handle and to separate from biological samples. In particular, the lipid bilayer surrounding magnetic particles is reportedly amenable to insertion of recombinant transmembrane proteins (5, 6). Calcite (calcium carbonate) precipitation is a well-known example of extracellular bacterial biomineralization. The precipitation of calcium carbonates by Halobacillus trueperi (spore-forming, moderately halophilic bacterium) isolated from hypersaline sediments of the Great Salt Lake in Utah has been investigated (7). Scanning electron microscopy indicated that the dominant morphology of H. trueperi calcium carbonate is spherulitic calcite with a fibrous radiated interior.In our own research, we isolated a biomineralizing thermophilic spore-forming bacterium from bark compost that has an optimum growth temperature of 60°C. Phylogenetic analysis of the 16S rRNA gene sequence identified the organism as Geobacillus thermoglucosidasius (8). Geobacillus spp. are a phenotypically and phylogenetically similar group of thermophilic bacilli (9). To date, we have found that G. thermoglucosidasius extracellularly catalyzes the formation of 100-m spheres and hexagonal crystals at 60°C in hydrogel containing sodium acetate, calcium chloride, and magnesium sulfate (calcite-promoting hydrogel). Microscopic analysis revealed that the minerals have polarizing properties and are thus highly crystallized. Under fluorescence microscopy, excitation occurred at 365 Ϯ 5, 480 Ϯ 20, and 545 Ϯ 15 nm, and broad-spectrum fluorescence was emitted with excitation at 350 nm. The maximum emitted wavelength was 446.9 nm for excitation at 369.6 nm. An X-ray diffraction analysis showed the crystals to be magnesium-calcite in the calcium carbonate group (8). From the observation that calcite was formed on both the interior and exterior of the G. thermoglucosidasius colony, we deduced that endospores constituted the nucleus of the calcites.The starvation for nitrogen and phosphate sources in calcitepromoting hydrogel promotes sporulation. In this study, we investiga...

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Enzymatic Modification of Aminoglycoside Antibiotics: a New 3- N -Acetylating Enzyme from a Pseudomonas aeruginosa Isolate

Abstract: A new 3- N -aminoglycoside acetyltransferase is described, which possesses a wider substrate range than any such enzyme so far discovered in clinical isolates of antibiotic-resistant bacteria.

Cited by 48 publications

References 8 publications

Aminoglycoside Resistance inPseudomonas aeruginosa

Aminoglycoside Resistance inPseudomonas aeruginosa

Correlation of aminoglycoside resistance with the KmS and Vmax/Km ratios of enzymatic modification of aminoglycosides by 2''-O-nucleotidyltransferase

Geobacillus thermoglucosidasius Endospores Function as Nuclei for the Formation of Single Calcite Crystals

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