Soil bacteria Pseudomonas putida and Alcaligenes xylosoxidans subsp. denitrificans inactivate triclosan in liquid and solid substrates

Meade, M

doi:10.1016/s0378-1097(01)00377-9

Cited by 27 publications

(33 citation statements)

References 16 publications

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“…Interestingly, Alcaligenes xylosoxidans subsp. denitrificans, previously implicated in TCS degradation (36), is closely related to the bacteria in cluster 1, as evidenced by phylogenetic placements of these species (Fig. 2).…”

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confidence: 55%

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Exposure of Sink Drain Microcosms to Triclosan: Population Dynamics and Antimicrobial Susceptibility

McBain

Bartolo

Catrenich

et al. 2003

Appl Environ Microbiol

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Recent concern that the increased use of triclosan (TCS) in consumer products may contribute to the emergence of antibiotic resistance has led us to examine the effects of TCS dosing on domestic-drain biofilm microcosms. TCS-containing domestic detergent (TCSD) markedly lowered biofouling at 50% (wt/vol) but was poorly effective at use levels. Long-term microcosms were established and stabilized for 6 months before one was subjected to successive 3-month exposures to TCSD at sublethal concentrations (0.2 and 0.4% [wt/vol]). Culturable bacteria were identified by 16S rDNA sequence analysis, and their susceptibilities to four biocides and six antibiotics were determined. Microcosms harbored ca. 10 log 10 CFU/g of biofilm, representing at least 27 species, mainly gamma proteobacteria, and maintained dynamic stability. Viable cell counts were largely unaffected by TCSD exposure, but species diversity was decreased, as corroborated by denaturing gradient gel electrophoresis analysis. TCS susceptibilities ranged widely within bacterial groups, and TCS-tolerant strains (including aeromonads, pseudomonads, stenotrophomonads, and Alcaligenes spp.) were isolated before and after TCSD exposure. Several TCS-tolerant bacteria related to Achromobacter xylosoxidans became clonally expanded during dosing. TCSD addition did not significantly affect the community profiles of susceptibility to the test biocides or antibiotics. Several microcosm isolates, as well as reference bacteria, caused clearing of particulate TCS in solid media. Incubations of consortia and isolates with particulate TCS in liquid led to putative TCS degradation by the consortia and TCS solubilization by the reference strains. Our results support the view that low-level exposure of environmental microcosms to TCS does not affect antimicrobial susceptibility and that TCS is degradable by common domestic biofilms.

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confidence: 55%

“…The detoxification of TCS by bacterial (18) and fungal (24) consortia has been recently reported to occur in activated sludge (13,18) and compost (36) samples. Earlier studies demonstrated environmental degradation of up to 50% of TCS added to sewage sludge under both aerobic and anaerobic conditions (53).…”

mentioning

confidence: 99%

Exposure of Sink Drain Microcosms to Triclosan: Population Dynamics and Antimicrobial Susceptibility

McBain

Bartolo

Catrenich

et al. 2003

Appl Environ Microbiol

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“…In some instances, these clonal expansions involve organisms that are not only intrinsically resistant but also are able to degrade the biocide, as has been shown recently for triclosan (112,186). In this respect, it is surprising that while trace levels of triclosan have been detected in human milk and fish bile and in human plasma (126), there is no apparent residual from its daily use in dentifrices (14).…”

Section: Discussionmentioning

confidence: 94%

“…Some microorganisms are able to demonstrate intrinsic resistance through inactivation of biocides. Biocides are less likely than antibiotics to be inactivated by bacteria, but examples include the inactivation of phenols and some aldehydes in species of Pseudomonas (273,302) and of triclosan (112,186). Enzymatic degradation of formaldehyde release agents by species such as Pseudomonas putida is, in some instances, sufficient to degrade the preservatives and enable spoilage by secondary colonizers (48).…”

Section: Reduced Susceptibility To Biocides Associated With Inductivementioning

confidence: 99%

Potential Impact of Increased Use of Biocides in Consumer Products on Prevalence of Antibiotic Resistance

2003

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There has recently been much controversy surrounding the increased use of antibacterial substances in a wide range of consumer products and the possibility that, as with antibiotics, indiscriminate use of biocides might contribute to the overall pattern of susceptibility in the general environment and in the clinic. Such speculation, based on the isolation of resistant mutants from in vitro monoculture experiments, is not reflected by an emergence of biocide-resistant strains in vivo. This review provides a broad coverage of the biocide and resistance literature and evaluates the potential risks, perceived from such laboratory monoculture experiments, against evidence gathered over 50 years of field studies. An explanation for the continued effectiveness of broad-spectrum biocidal agents against the decline in efficacy of therapeutic agents is provided based on the fitness costs of resistance and the ubiquity of naturally occurring substances that possess antibacterial effect. While we conclude from this review of the literature that the incorporation of antibacterial agents into a widening sphere of personal products has had little or no impact on the patterns of microbial susceptibility observed in the environment, the associated risks remain finite. The use of such products should therefore be associated with a clear demonstration of added value either to consumer health or to the product life. Hygienic products should therefore be targeted to applications for which the risks have been established

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“…Enzymatic degradation of triclosan has been demonstrated in two soil bacteria, Pseudomonas putida TriRY and Alcaligenes xylosoxidans subsp. denitrificans TR1, which were shown to grow on medium containing 1% triclosan (37). Triclosan degradation has also been shown in Sphingomonas sp.…”

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confidence: 85%

Identification and Characterization of TriABC-OpmH, a Triclosan Efflux Pump of Pseudomonas aeruginosa Requiring Two Membrane Fusion Proteins

et al. 2007

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Pseudomonas aeruginosa achieves high-level (MIC > 1 mg/ml) triclosan resistance either by constitutive expression of MexAB-OprM, an efflux pump of the resistance nodulation cell division (RND) family, or expression of MexCD-OprJ, MexEF-OprN, and MexJK-OpmH in regulatory mutants. A triclosan-resistant target enzyme and perhaps other mechanisms probably act synergistically with efflux. To probe this notion, we exposed the susceptible ⌬(mexAB-oprM) ⌬(mexCD-oprJ) ⌬(mexEF-oprN) ⌬(mexJK) ⌬(mexXY) strain PAO509 to increasing triclosan concentrations and derived a resistant strain, PAO509.5. This mutant overexpressed the PA0156-PA0157-PA0158 pump, which only effluxed triclosan, but not closely related compounds, antibiotics, and divalent cations, and was therefore renamed TriABC. Constitutive expression of the triABC operon was due to a single promoter-up mutation. Deletion of two adjacent genes, pcaR and PA0159, encoding transcriptional regulators had no effect on expression of this operon. TriABC is the only P. aeruginosa RND pump which contains two membrane fusion proteins, TriA and TriB, and both are required for efflux pump function. Probably owing to tight transcriptional coupling of the triABC genes, complementation of individual mutations was only partially achievable. Full complementation was only observed when a complete triABC operon was provided in trans, either in single or multiple copies. TriABC associated with OpmH, but not OprM, for assembly of a functional triclosan efflux pump. TriABC is the fifth RND pump in P. aeruginosa shown to efficiently efflux triclosan, supporting the notion that efflux is the primary mechanism responsible for this bacterium's high intrinsic and acquired triclosan resistance.

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Soil bacteria Pseudomonas putida and Alcaligenes xylosoxidans subsp. denitrificans inactivate triclosan in liquid and solid substrates

Cited by 27 publications

References 16 publications

Exposure of Sink Drain Microcosms to Triclosan: Population Dynamics and Antimicrobial Susceptibility

Exposure of Sink Drain Microcosms to Triclosan: Population Dynamics and Antimicrobial Susceptibility

Potential Impact of Increased Use of Biocides in Consumer Products on Prevalence of Antibiotic Resistance

Identification and Characterization of TriABC-OpmH, a Triclosan Efflux Pump of Pseudomonas aeruginosa Requiring Two Membrane Fusion Proteins

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