Nucleotide sequence analysis and DNA hybridization studies of the ant(4')-IIa gene from Pseudomonas aeruginosa

Shaw, Karen Joy; Munayyer, H.; Rather, Philip N.; Hare, R S; Miller, George H.

doi:10.1128/aac.37.4.708

Cited by 13 publications

(10 citation statements)

References 22 publications

(23 reference statements)

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“…The AME gene with the largest difference in expression between B1 and the sensitive mutants was ant(4Ј)-IIa, which encodes for an AME that has been shown to confer resistance to both tobramycin and amikacin (79). However, the level of amikacin resistance displayed by B1 is an order of magnitude lower than the MICs previously reported for other P. aeruginosa strains expressing this gene (34,75,78). Aminoglycoside-resistant isolates of serotype O12 have been reported to react with probes for the genes ant(3Ј) and aac(6Ј)-I and -II (46).…”

Section: Discussionmentioning

confidence: 67%

Reverse Engineering Antibiotic Sensitivity in a Multidrug-Resistant Pseudomonas aeruginosa Isolate

Struble

Gill

2006

Antimicrob Agents Chemother

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Antibiotic resistance is a pervasive and growing clinical problem. We describe an evaluation of a reverse engineering approach for identifying cellular mechanisms and genes that could be manipulated to increase antibiotic sensitivity in a resistant Pseudomonas aeruginosa isolate. We began by chemically mutating a broadly resistant isolate of P. aeruginosa and screening for mutants with increased sensitivity to the aminoglycoside amikacin, followed by performing whole-genome transcriptional profiling of the mutant and wild-type strains to characterize the global changes occurring as a result of the mutations. We then performed a series of assays to characterize the mechanisms involved in the increased sensitivity of the mutant strains. We report four primary results: (i) mutations that increase sensitivity occur at a high frequency (10 ؊2 ) relative to the frequency of those that increase resistance (10 ؊5 to 10 ؊10 ) and occur at a frequency 10 4 higher than the frequency of a single point mutation; (ii) transcriptional profiles were altered in sensitive mutants, resulting in overall expression patterns more similar to those of the sensitive laboratory strain PAO1 than those of the parental resistant strain; (iii) genes found from transcriptional profiling had the more dramatic changes in expression-encoded functions related to cellular membrane permeability and aminoglycoside modification, both of which are known aminoglycoside resistance mechanisms; and finally, (iv) even though we did not identify the specific sites of mutation, several different follow-up MIC assays suggested that the mutations responsible for increased sensitivity differed between sensitive mutants.Antibiotic resistance develops rapidly after the introduction of a new antibiotic and now exists, to some extent, for all antibiotics. Resistance has even evolved for drugs specifically designed to prevent selection for resistance (10,23,27,30,43,52,74,85,86). These factors underline the importance of understanding the genetic and phenotypic bases underlying antibiotic resistance and developing new strategies to combat the proliferation of resistant organisms. One approach has been to combine new and conventional antibiotics to simultaneously increase the sensitivities of resistant organisms and target essential genes (40,50,51,73). The success of such an approach is dependent upon the identification of genes and/or mechanisms that might be targeted to increase sensitivity. We report here on our efforts to evaluate a reverse engineering approach for identifying such genes and mechanisms. Specifically, we have identified aminoglycoside-sensitive mutants of a multiple-drug-resistant Pseudomonas aeruginosa isolate and characterized the global changes in gene expression associated with mutations that restored sensitivity in two of these mutants as well as the resistant parental strain and the sensitive laboratory strain PAO1.We chose to study a clinical isolate, named B1, that showed high levels of resistance to five aminoglycosides tested: amikacin,...

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Section: Discussionmentioning

confidence: 67%

Reverse Engineering Antibiotic Sensitivity in a Multidrug-Resistant Pseudomonas aeruginosa Isolate

Struble

Gill

2006

Antimicrob Agents Chemother

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“…(267). The gene for ANT(4Ј)-IIa adenyltransferase was originally cloned from Pseudomonas aeruginosa (139), and its nucleotide sequence has been determined (267). No homology was found between ANT(4Ј)-IIa and ANT(4Ј)-Ia.…”

Section: Aminoglycoside Nucleotidyltransferasesmentioning

confidence: 99%

“…In contrast to ANT(4Ј)-I, ANT(4Ј)-IIa is found only among gram-negative bacteria, including many representatives of the Enterobacteriaceae and Pseudomonas spp. (267). The gene for ANT(4Ј)-IIa adenyltransferase was originally cloned from Pseudomonas aeruginosa (139), and its nucleotide sequence has been determined (267).…”

Section: Aminoglycoside Nucleotidyltransferasesmentioning

confidence: 99%

Versatility of Aminoglycosides and Prospects for Their Future

2003

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Aminoglycoside antibiotics have had a major impact on our ability to treat bacterial infections for the past half century. Whereas the interest in these versatile antibiotics continues to be high, their clinical utility has been compromised by widespread instances of resistance. The multitude of mechanisms of resistance is disconcerting but also illuminates how nature can manifest resistance when bacteria are confronted by antibiotics. This article reviews the most recent knowledge about the mechanisms of aminoglycoside action and the mechanisms of resistance to these antibiotics

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“…The ANT(2Љ)-I enzyme inactivates gentamicin and tobramycin but not netilmicin or amikacin and is thus found in gentamicinresistant (19,31,114,123) and tobramycin-resistant (89) clinical isolates. Other adenyltransferases associated with aminoglycoside resistance in P. aeruginosa include ANT(3Љ) (streptomycin resistance) (146) and ANT(4Ј)-II (amikacin, tobramycin, and isepamicin resistance) (63,132,147). Two variants of ANT(4Ј)-II, ANT(4Ј)-IIa (63,147) and ANT(4Ј)-IIb (132), have been reported and are encoded by genes present in the chromosome and/or on plasmids of amikacin-resistant clinical isolates.…”

Section: Modifying Enzymesmentioning

confidence: 99%