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Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water.

Schwartz T, Armant O, Bretschneider N, Hahn A, Kirchen S, Seifert M, Dötsch A - Microb Biotechnol (2014)

Bottom Line: The expression of resistance genes, genetic mobile elements in PA49 was independent from the water matrix.Consistently, the antibiotic sensitive strain PA30 did not show any difference in expression of the intrinsic resistance determinants and genetic mobile elements.However, changes in environmental milieus resulted in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Functional Interfaces (IFG), Campus North, Karlsruhe Institute of Technology (KIT), Hermann von Helmholtz Platz 1, Eggenstein-Leopoldshafen, D-76344, Germany.

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Related in: MedlinePlus

Expression of specific genes in strain PA30 and PA49 in different water matrices. Absolute gene expression values are depicted as box plots for the different samples of strain PA30 and PA49 cultivated in tap water (T) and waste water (W). Genes were manually selected by their functional classification as resistance (associated with modification and deactivation of antibiotics), mobility (associated with horizontal gene transfer and recombination), metal (associated with heavy metal tolerance), efflux (associated with multi-drug efflux pumps) or other (not included in any other class). Asterisks indicate a significant difference in the medians of the particular gene class and the other genes determined with the Mann–Whitney–Wilcoxon test (*P < 0.05; **P < 0.001).
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fig04: Expression of specific genes in strain PA30 and PA49 in different water matrices. Absolute gene expression values are depicted as box plots for the different samples of strain PA30 and PA49 cultivated in tap water (T) and waste water (W). Genes were manually selected by their functional classification as resistance (associated with modification and deactivation of antibiotics), mobility (associated with horizontal gene transfer and recombination), metal (associated with heavy metal tolerance), efflux (associated with multi-drug efflux pumps) or other (not included in any other class). Asterisks indicate a significant difference in the medians of the particular gene class and the other genes determined with the Mann–Whitney–Wilcoxon test (*P < 0.05; **P < 0.001).

Mentions: The four horizontally acquired antibiotic resistance genes found in strain PA49 (Table 1) were transcriptionally active independent from the water matrix and therefore most likely are a main cause of the observed resistance towards a wide spectrum of aminoglycoside and beta-lactam antibiotics (Table 2). Genes associated with antibiotic resistance (not including multi-drug efflux pumps) showed a higher average expression as compared with the rest of the genome in PA49 (Fig. 4), which is obviously a result of the generally high expression of horizontally acquired resistance genes (Table 2). This tendency was independent from the water matrix and not found in the transcriptome of PA30 (Fig. 4), which lacks such additional resistance genes (Fig. 2). A common cause of antibiotic resistance in P. aeruginosa is the overexpression of multi-drug efflux pumps (usually termed ‘Mex’ pumps). Indeed, the genes encoding the MexCD-OprJ efflux pump were overexpressed in PA49 in response to waste water (Table 5 and Table S5). This pump system can confer resistance towards a broad spectrum of antibiotics (Poole et al., 1996) and thus may further contribute to the multi-resistance phenotype of PA49. The induced expression of this efflux pump specifically in waste water is indicating a specific stimulation presumably by one or multiple of antibiotics found in the used waste water or via so far unknown waste water components. However, since the expression of specific resistance genes and presence of resistance-related target mutations already sufficiently explains the broad resistance phenotype in PA49 (Table 1), the exact contribution of a MexCD-OprJ overexpression remains unclear. It should be again pointed out that the expression of resistance genes (with the exception of MexCD-OprJ) in PA49 was independent from the water matrix. Similarly, the antibiotic sensitive strain PA30 does not show any difference in expression of the intrinsic resistance determinants. Thus, the exposure of both strains to polluted waste water and oligotrophic tap water resulted in similar expression profiles of resistance genes. It seems to be obvious that changes in environmental milieus result in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation.


Whole genome and transcriptome analyses of environmental antibiotic sensitive and multi-resistant Pseudomonas aeruginosa isolates exposed to waste water and tap water.

Schwartz T, Armant O, Bretschneider N, Hahn A, Kirchen S, Seifert M, Dötsch A - Microb Biotechnol (2014)

Expression of specific genes in strain PA30 and PA49 in different water matrices. Absolute gene expression values are depicted as box plots for the different samples of strain PA30 and PA49 cultivated in tap water (T) and waste water (W). Genes were manually selected by their functional classification as resistance (associated with modification and deactivation of antibiotics), mobility (associated with horizontal gene transfer and recombination), metal (associated with heavy metal tolerance), efflux (associated with multi-drug efflux pumps) or other (not included in any other class). Asterisks indicate a significant difference in the medians of the particular gene class and the other genes determined with the Mann–Whitney–Wilcoxon test (*P < 0.05; **P < 0.001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321378&req=5

fig04: Expression of specific genes in strain PA30 and PA49 in different water matrices. Absolute gene expression values are depicted as box plots for the different samples of strain PA30 and PA49 cultivated in tap water (T) and waste water (W). Genes were manually selected by their functional classification as resistance (associated with modification and deactivation of antibiotics), mobility (associated with horizontal gene transfer and recombination), metal (associated with heavy metal tolerance), efflux (associated with multi-drug efflux pumps) or other (not included in any other class). Asterisks indicate a significant difference in the medians of the particular gene class and the other genes determined with the Mann–Whitney–Wilcoxon test (*P < 0.05; **P < 0.001).
Mentions: The four horizontally acquired antibiotic resistance genes found in strain PA49 (Table 1) were transcriptionally active independent from the water matrix and therefore most likely are a main cause of the observed resistance towards a wide spectrum of aminoglycoside and beta-lactam antibiotics (Table 2). Genes associated with antibiotic resistance (not including multi-drug efflux pumps) showed a higher average expression as compared with the rest of the genome in PA49 (Fig. 4), which is obviously a result of the generally high expression of horizontally acquired resistance genes (Table 2). This tendency was independent from the water matrix and not found in the transcriptome of PA30 (Fig. 4), which lacks such additional resistance genes (Fig. 2). A common cause of antibiotic resistance in P. aeruginosa is the overexpression of multi-drug efflux pumps (usually termed ‘Mex’ pumps). Indeed, the genes encoding the MexCD-OprJ efflux pump were overexpressed in PA49 in response to waste water (Table 5 and Table S5). This pump system can confer resistance towards a broad spectrum of antibiotics (Poole et al., 1996) and thus may further contribute to the multi-resistance phenotype of PA49. The induced expression of this efflux pump specifically in waste water is indicating a specific stimulation presumably by one or multiple of antibiotics found in the used waste water or via so far unknown waste water components. However, since the expression of specific resistance genes and presence of resistance-related target mutations already sufficiently explains the broad resistance phenotype in PA49 (Table 1), the exact contribution of a MexCD-OprJ overexpression remains unclear. It should be again pointed out that the expression of resistance genes (with the exception of MexCD-OprJ) in PA49 was independent from the water matrix. Similarly, the antibiotic sensitive strain PA30 does not show any difference in expression of the intrinsic resistance determinants. Thus, the exposure of both strains to polluted waste water and oligotrophic tap water resulted in similar expression profiles of resistance genes. It seems to be obvious that changes in environmental milieus result in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation.

Bottom Line: The expression of resistance genes, genetic mobile elements in PA49 was independent from the water matrix.Consistently, the antibiotic sensitive strain PA30 did not show any difference in expression of the intrinsic resistance determinants and genetic mobile elements.However, changes in environmental milieus resulted in rather unspecific transcriptional responses than selected and stimuli-specific gene regulation.

View Article: PubMed Central - PubMed

Affiliation: Institute of Functional Interfaces (IFG), Campus North, Karlsruhe Institute of Technology (KIT), Hermann von Helmholtz Platz 1, Eggenstein-Leopoldshafen, D-76344, Germany.

Show MeSH
Related in: MedlinePlus