SEARCH · PubMed Health

Results for “Environmental selection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources

PubMedDate not supplied

Evaluation of regional environmental and health hazards by applying synthetic measures.

Large geographical areas, urban and rural regions of 49 voivodships in Poland, were evaluated from the point of view of existing environmental and health hazards caused by chemical contamination of the environment. Using routine sources of information, we selected four health-related environmental indicators and eight environmental-related health indicators. All indicator values were normalized and then aggregated to synthetic measures of environmental and health hazards, using the taxonometric method. The synthetic measures characterized the urban and rural regions of the entire country and were used for their ranking for remedial purposes. A consistency of environmental and health synthetic measures was found in urban regions (correlation coefficient r = 0.58). The spatial distribution of environmental and health hazards was determined using geo-graphical information system (GIS) methods. The application of kriging and the interpolation of data improved the interpretation of the results. The worst situation was found in the southwest regions of Poland, which are heavily industrialized with a high population density.

Environmental Monitoring↗

PubMed2006

Efficient inefficiency: biochemical "junk" may represent molecular bridesmaids awaiting emergent function as a buffer against environmental fluctuation.

The biochemical function of many parts of the genome, transcriptome, proteome, and interactome remain largely unknown. We propose that portions of these fundamental building blocks of life have no current biochemical function per se. Rather, sections of these "omes" may contribute to an inventory of biochemical parts and circuits that participate in the development of emergent functions. Low fidelity deoxyribonucleic acid replication, transcription, translation, and post-translational modification all represent potential mechanisms to produce an inventory of parts. Stochastic processes that influence the conformations of ribonucleic acid molecules and proteins may also contribute to potential biochemical inventory. Some components of the biochemical inventory may enable future adaptations, some may produce disease, and some may remain useless. The function of many of these components await discovery, not by science, but by evolution. While carrying such purposeless biochemical units may appear to dilute fitness by exacting a thermodynamic cost, we argue that net fitness becomes enhanced when considering the value for potential future innovations. One can envision components that intermingle, interact, and act out mock pathways, but in most cases remain molecular bridesmaids. Given sufficiently low thermodynamic cost, such stochastic cycling may persist until a markedly advantageous or cataclysmically disadvantageous trait emerges. Maladaptive screening and utilization of inventory content can lead to disease phenotypes, a process buffered and regulated in part by the heat shock protein and stress response network. Whereas failure of the ubiquitin pathway to recycle misfolded proteins has become increasingly recognized as a source of disease, protein misfolding may itself represent one step in a process that maximizes functional innovation through increasing proteomic diversity. Fractal correlates of these processes occur at the organizational level of cells and organisms. That the abnormal accumulation of units induces local collapse may serve to limit the extension of damage to the greater system at large. The immune and cognitive systems that selectively sample and prune environmental content may serve as additional portals for innovation.

Adaptation, Physiological↗

PubMed1978

Environmentally triggered cardiac disease.

Twelve highly selected patients with non-arteriosclerotic cardiac arrhythmias and/or chest pain refractory to medication and having symptoms related to smooth muscle sensitization were studied in a rigidly controlled, relatively fume- and particle-free environment. The majority of signs and symptoms cleared in 10 patients without medication while under environmental control, and in 10 of the 12 patients all arrhythmias were reproduced with controlled, repeated individual-blind and double-blind incitant challenges. Blood abnormalities occurred in the complement and T-lymphocyte systems.

Adolescent↗

PubMed1999

The importance of genetic and environmental effects for self-reported health symptoms: a 30-year follow-up considering survival and selection effects.

OBJECTIVES: This study delineated the nature of individual differences in self-reported health status across a 30-year period. Potential survival and selection effects on mean levels, variances, and genetic and environmental sources of variance were evaluated. METHODS: Self-reported health status in 1963 was evaluated in 5,229 pairs of twins from the Swedish Twin Registry and in a subsample of 351 pairs surviving to the age of 80 years in 1993. Structural equation modeling evaluated genetic and environmental contributions to total variance and change in variance. RESULTS: For men but not women, the genetic and environmental influences on health symptoms differed between survivors and nonsurvivors. Total variance increased, reflecting an increase in environmental variance, across the 30 years for both genders. Genetic variance decreased longitudinally for men. DISCUSSION: The increase in variation from the mid-50s to the mid-80s appears to be due to an accumulation in environmental variation. There are gender differences that deserve further exploration.

Age Factors↗

PubMed1992

Nearly identical T-cell receptor V-gene usage at birth in two cohorts of distinctly different ethnic origin: influence of environment in the final maturation in the adult.

We have previously analysed the T-cell receptor (TCR) V-gene usage in peripheral blood T lymphocytes from a group of healthy Scandinavians, and described a biased representation (i.e. a statistically significant higher median representation) for some of the TCR V genes towards the CD4+ subpopulation. In a subsequent study the usage of the same V genes was analysed in single positive (CD4+ CD8- and CD4- CD8+) human thymocytes, and a similar type of skewness was noted. These observations might be explained by an influence of the specificity of the TCR of thymocytes on the maturation into the CD4+ or the CD8+ lineage. Such a model would assume an interaction between a common determinant on the major histocompatibility complex (MHC) class I or class II molecules, or with a peptide that is preferentially presented by either of the two molecules, and the TCR on the maturing thymocyte. To investigate the possible influence of a different genetic background and environment on skewed TCR V-gene representation, we have in this study analysed the TCR V-gene usage in peripheral blood and umbilical cord blood lymphocytes obtained from Asians, with a different ethnic and environmental background from our previous Scandinavian subjects. In the umbilical cord blood lymphocytes the TCR V-gene usage was close to identical between the two different ethnic groups in both CD4+ and CD8+ subpopulations. Analysing the peripheral blood lymphocyte (PBL) TCR V-gene usage, we found that three of the four monoclonal antibodies (MoAb) with a biased reactivity towards the CD4+ subpopulation in the Scandinavian group also showed a similar skewed reactivity in this study. Thus, the majority of the TCR V genes were used in a similar way. Some minor but definite discrepancies could be detected when comparing TCR V-gene usage in adult individuals from these two different ethnic groups. These differences could be inferred to be due to selective peripheral expansion through environmental pressure of T cells utilizing a specific V beta gene segment. We conclude that a striking preservation of biased TCR V-gene usage does exist in humans of distinctly different ethnic origin.

Age Factors↗

PubMed1990

Fluctuating asymmetry: an epigenetic measure of stress.

(1) Fluctuating asymmetry (FA) is a useful trait for monitoring stress in the laboratory and in natural environments. (2) Both genomic and environmental changes can increase FA which represents a deterioration in developmental homeostasis apparent in adult morphology. Genetic perturbations include intense directional selection and certain specific genes. Environmental perturbations include temperature extremes in particular, protein deprivation, audiogenic stress, and exposure to pollutants. (3) There is a negative association between FA and heterozygosity in a range of taxa especially fish, a result consistent with FA being a measure of fitness. (4) Scattered reports on non-experimental populations are consistent with experiments under controlled laboratory conditions. FA tends to increase as habitats become ecologically marginal; this includes exposure to environmental toxicants. (5) In our own species, FA of an increasing range of traits has been related to both environmental and genomic stress. (6) Domestication increases FA of the strength of homologous long bones of vertebrate species due to a relaxation of natural selection. (7) FA levels are paralleled by the incidence of skeletal abnormalities in stressful environments. (8) Increased FA is a reflection of poorer developmental homeostasis at the molecular, chromosomal and epigenetic levels.

Animals↗

PubMed1998

A new method for evaluating motor control in gait under real-life environmental conditions. Part 2: Gait analysis.

OBJECTIVE: The validity of assessing balance in gait by measuring balance in standing is questionable. Better methods for measuring balance during walking are therefore needed. DESIGN: It is suggested that the individual will demonstrate adequate postural control by moving a reference point near the body centre of mass (CoM) smoothly towards an intentional goal, even though movements of the extremities show variability consistent with a changing environment. BACKGROUND: In spite of an increased interest in variability as a prerequisite for motor control, gait analysis methods focus, to a large extent, on symmetry and repeatability of movements in stereotyped settings. METHODS: Acceleration of a reference point over the lumbar spine is registered during walking by a portable, triaxial accelerometry system. RESULTS: A quadratic relation between acceleration root mean square (RMS) and walking speed is demonstrated, and a second degree polynomial can therefore be computed as a curve estimate, if acceleration RMS representing at least three walking speeds are available. CONCLUSIONS: The relation between acceleration over a reference point on the trunk and walking speed can be compared between trials and also when walking speeds are self-selected. Calibration procedures and testing of the instrument for precision and accuracy in a mechanical testing jig are described in a companion article. RELEVANCE: This study suggests a new alternative to the traditions of measuring balance in standing and movements of the legs in walking. The method allows balance in gait to be assessed at self-selected speeds in relevant environmental conditions, which may facilitate gait analysis in the clinic and improve the validity of the results.

Journal Article↗

PubMed1994

Exercise electrocardiography and aortic Doppler velocimetry in asymptomatic identical twins discordant for type 1 (insulin dependent) diabetes.

OBJECTIVE: To determine the influence of insulin dependent diabetes on the prevalence of myocardial ischaemia and on global left ventricular systolic performance. DESIGN: Stress treadmill electrocardiograms and simultaneous Doppler measurement of aortic maximum acceleration were obtained during exercise on symptom free subjects. The electrocardiograms were scored blindly according to the Minnesota code. PARTICIPANTS: 39 identical twin pairs (22 male) discordant for insulin dependent diabetes and 39 non-diabetic controls of similar age and sex were examined. The twins and controls had a mean age of 37 (range 25-69) with a mean (SD) duration of diabetes in the diabetic twin of 17 (7) years. Those selected were normotensive and had no renal impairment. RESULTS: Systolic blood pressure was significantly higher in the diabetic twins than in their non-diabetic cotwins both at rest (p < 0.05) and at peak exercise (p < 0.01). Electrocardiographic evidence of ischaemia was not correlated within twin pairs and was found in similar numbers of diabetic twins, their non-diabetic cotwins, and control subjects. Abnormal electrocardiograms were found in a similar number of diabetic twins (23%), non-diabetic cotwins (18%), and controls (15%). There was a significant correlation in Doppler measurements of global left ventricular systolic function within the identical twins; no significant difference was found for these Doppler measurements in the diabetic twins, non-diabetic cotwins, or controls. CONCLUSION: Exercise characteristics and cardiac function seem to be subject to shared genetic or shared environmental influences or both, whereas electrocardiographic features of ischaemia seem to be environmentally determined. In a selected cohort of diabetic identical twins without evidence of nephropathy there was no evidence that diabetes influenced the prevalence of myocardial ischaemia or global left ventricular systolic function.

Adult↗

PubMed2000

Results of the health survey of a population living in a vicinity of a large waste site (Warsaw, Poland).

Although attracting rapidly increasing attention from the public, the health impact of environmental exposures related to the operation of waste dumping sites is a relatively new issue in Poland. However, the problem cannot be neglected in light of the fact that environmental impact assessment in selected sites revealed the lack of sufficient documentation concerning quantity and quality of dumped materials and poor technological management of the sites. The paper describes the results of health survey performed in a vicinity of a country's largest municipal waste site. Although the study came across methodological obstacles involving low participation and difficult to estimate representativeness of the examined group its findings obtained in 393 adults and 188 children and the results of internal comparisons revealed some interesting observations. Three "exposure-classification" variables were used in data analysis (geographical location, distance, "waste traffic" intensity) and health status was examined by means of self- and physician-administered questionnaire, physical examination and routine laboratory analyses. Relationship, although weak, of subjective symptoms and objective findings with the place of residence vis-a-vis the waste site location suggests that potential health effects of waste site-related environmental exposures might include psychological problems, digestive tract disorders and respiratory disorders as well as allergic symptoms. An intriguing observation concerning pregnancy-related health outcomes was made. The exact role of environmental determinants in this respect remains unclear and should be addressed by specific environmental epidemiological and toxicological studies. The findings as well as subjects' concern about health consequences of exposures to waste-related pollution (paralleled by subjective perception of impaired health) justify further investigations and public health initiatives including environmental impact assessment and health monitoring activities targeting populations living in a vicinity of waste sites in Poland.

Abortion, Spontaneous↗

PubMed1989

Ethanol reinforcement in the alcohol nonpreferring rat: initiation using behavioral techniques without food restriction.

Genetic selection of rats can markedly alter their ethanol consumption. The manner in which environmental factors interact in these genetically selected animals to influence ethanol consumption has not been thoroughly investigated. Using the alcohol-nonpreferring (NP) line of rats selectively bred at the Indiana University School of Medicine, alcohol self-administration in an operant situation was initiated using either a sucrose-fading or a secondary-conditioning procedure. These initiation procedures do not require any food or fluid restriction. Initiation was successful in 10 out of 12 NP animals, with the initiated rats self-administering ethanol at concentrations as high as 40%. Following initiation, a retest of home-cage ethanol preference found increases in ethanol acceptability. When tested in a concurrent operant situation, the initiated NP rats also chose ethanol over water. However, the NP rats had lower alcohol intakes and a different pattern of drinking over time when compared to that of nonselected Long-Evans rats. While the NP rats could be initiated to lever-press for ethanol, at no time did their intake approach that of the selected line of alcohol-preferring (P) rats. Thus, while an upward shift from the genetic baseline in ethanol preference and intake can result from the environmental initiation manipulations employed in these studies, genetic factors would appear to limit the extent to which ethanol ingestion can be increased.

Alcohol Drinking↗

PubMed1987

Dynamic structures and functions of transfer ribonucleic acids from extreme thermophiles.

tRNA species from an extreme thermophile T. thermophilus that grows up to 85 degrees C have been found to be more thermostable than those from moderate thermophiles and mesophiles. Such thermostability of T. thermophilus tRNA species is partly due to the high contents of G.C base pairs in the stem regions. In addition, a novel modified nucleoside s2T has been found that substitutes T in position 54. The extent of 2-thiolation of T(54) has been found to depend on environmental temperatures from 50 to 80 degrees C. Two tRNA(Ile) species have been isolated from T. thermophilus HB8, tRNA(1aIle) with s2T(54) and tRNA(1bIle) with T(54), which have the identical nucleotide sequence except for position 54. However, the melting temperature of tRNA(1aIle) is higher by 3 degrees C than that of tRNA(1bIle). This clearly indicates that the 2-thiolation of T(54) contributes directly to the thermostability of T. thermophilus tRNA species. Proton NMR analyses have shown that the nucleoside s2T is "rigid" and predominantly takes the C3'-endo-gg-anti form of A-RNA, because of the steric effect of the bulky 2-thiocarbonyl groups and the 2'-hydroxyl group. Thus, the inherent rigidity of s2T in position 54 significantly enhances the stability of the tertiary structure of tRNA. In protein synthesis of T. thermophilus, s2T(54)-bearing tRNA and T(54)-bearing tRNA species are selectively utilized depending on environmental temperature. In the anticodons of major tRNA species from T. thermophilus, G or C exclusively appears in the first position, and GGN and CCN are favored over synonymous GCN or CGN. These characteristic anticodon sequences correspond to the characteristic codon usage in thermophile genes.

Anticodon↗

PubMed2006

Heritability of corticosterone response and changes in life history traits during selection in the zebra finch.

Vertebrates respond to environmental stressors through the neuro-endocrine stress response, which involves the production of glucocorticoids. We have selected independent, duplicate divergent lines of zebra finches for high, low and control corticosterone responses to a mild stressor. This experiment has shown that over the first four generations, the high lines have demonstrated a significant realized heritability of about 20%. However, the low lines have apparently not changed significantly from controls. This asymmetry in response is potentially because of the fact that all birds appear to be showing increased adaptation to the environment in which they are housed, with significant declines in corticosterone response in control lines as well as low lines. Despite the existence of two- to threefold difference in mean corticosterone titre between high and low lines, there were no observed differences in testosterone titre in adult male birds from the different groups. In addition, there were no consistent, significant differences between the lines in any of the life history variables measured--number of eggs laid per clutch, number of clutches or broods produced per pair, number of fledglings produced per breeding attempt, nor in any of egg, nestling and fledgling mortality. These results highlight the fact that the mechanisms that underlie variation in the avian physiological system can be modified to respond to differences between environments through selection. This adds an additional level of flexibility to the avian physiological system, which will allow it to respond to environmental circumstances.

Animals↗

PubMedDate not supplied

The problems of environmental hazardous substances: an overview.

It was decided to present an overview of problems of environmental hazardous substances by selecting three areas of concern which represent different aspects of the overall subject. All three are topics of great interest at the present time. They provide examples of different causes of the hazards and different approaches to their resolution or containment. Aerial and water contamination by radon gas are a natural hazard only recently recognized. Radon can be contained, but it will require cooperative action and expenditure. Herbicides are a continuing problem demanding increased research activity to establish risk-benefit decisions. Pollution of estuaries and oceans require new development of models for establishing safe levels of some pollutants and prohibition of others.

Air Pollutants, Radioactive↗

PubMed1998

A highly selective PCR protocol for detecting 16S rRNA genes of the genus Pseudomonas (sensu stricto) in environmental samples.

Pseudomonas species are plant, animal, and human pathogens; exhibit plant pathogen-suppressing properties useful in biological control; or express metabolic versatilities valued in biotechnology and bioremediation. Specific detection of Pseudomonas species in the environment may help us gain a more complete understanding of the ecological significance of these microorganisms. The objective of this study was to develop a PCR protocol for selective detection of Pseudomonas (sensu stricto) in environmental samples. Extensive database searches identified a highly selective PCR primer pair for amplification of Pseudomonas 16S rRNA genes. A protocol that included PCR amplification and restriction analysis, a general cloning and sequencing strategy, and phylogenetic analyses was developed. The PCR protocol was validated by testing 50 target and 14 nontarget pure cultures, which confirmed the selectivity to 100%. Further validation used amplification of target sequences from purified bulk soil DNA followed by cloning of PCR products. Restriction analysis with HaeIII revealed eight different fragmentation patterns among 36 clones. Sequencing and phylogenetic analysis of 8 representative clones indicated that 91.7% of the products were derived from target organisms of the PCR protocol. Three patterns, representing only 8.3% of the 36 clones, were derived from non-Pseudomonas or chimeric PCR artifacts. Three patterns, representing 61.1% of the clones, clustered with sequences of confirmed Pseudomonas species, whereas two patterns, representing 30.6% of the clones, formed a novel phylogenetic cluster closely associated with Pseudomonas species. The results indicated that the Pseudomonas-selective PCR primers were highly specific and may represent a powerful tool for Pseudomonas population structure analyses and taxonomic confirmations.

DNA Primers↗

PubMed1991

Genetic and environmental determinants of hypopus duration in the stored-product mite Lepidoglyphus destructor.

This paper reports a series of experiments over many years on hypopus duration and extends the preceding investigation (1987) on hypopus formation in Lepidoglyphus destructor (Schrank, 1781). The length of time required for hypopus physiogenesis (diapause development) is genetically programmed but influenced by environmental factors. This span of time is highly variable, and may extend from one week to more than a year. Spreading out the potential for hypopus completion over time is adaptive, since a pool of hypopodes with prolonged and staggered dormancies serves to spread the risk of emergence of tritonymphs over extended periods of time; it buffers the population against sudden drought to which all other stages of the life-cycle succumb. The additive structure and large variance of the genetic system underlying the length of time required for hypopus physiogenesis allows for the reconstitution of a broad spectrum of genotypes in every generation through the process of meiotic segregation and recombination during sexual reproduction. It favours stored variability, provides a 'fail-safe device' both for survival as well as development in irregularly fluctuating environments, and facilitates the adaptation of populations to local conditions. The trait for hypopus physiogenesis varies independently from that of hypopus formation, and is apparently free to adjust, without genetic constraints, towards an adaptive optimum. The response to selection is fast. Low environmental humidities and high temperatures accelerate physiogenesis of the hypopus. Completion of the hypopus stage and moulting to the tritonymph is triggered by high humidities at moderate temperatures. If environmental conditions preclude moulting, the hypopus following ending of physiogenesis enters a state of quiescence. In contrast the seasonal and largely predictably varying environments, in which essentially anticipatory and season-related token cues like photoperiod regulate the timing of so many arthropod life-cycles, L. destructor copes with sudden and fatal drought, as well as with unheralded and favourable humidities in its ephemeral habitats, mainly by excessive genetic polymorphism in hypopus duration and formation; some genotypes are always instantaneously fit to meet the respective environmental situation. The mite faces gradual food deterioration of its patchily distributed microhabitats by a short-term anticipatory and environmentally cued developmental switch mechanism, which lowers the threshold for hypopus induction. On top of genetic variability and phenotypic plasticity, any genotype X environment interaction provides for increasing flexibility above that from genetic polymorphism and environmental polyphenism alone. This extraordinary measure of adaptedness fits L. destructor for life in irregularly fluctuating environments.

Animals↗

PubMed1981

Influence of environmental temperature and humidity on bronchial responses during assessment of selectivity of beta-adrenoceptor antagonists in man.

1 The effects of beta-adrenoceptor antagonists given intravenously in single doses were examined in a double-blind, placebo controlled study performed in six healthy volunteers. Heart rate and peak expiratory flow rate (PEFR) were measured at rest and during standardised exercise. 2 Atenolol 0.2 mg/kg, betaxolol 0.15 mg/kg, practolol 1 mg/kg and propranolol 0.2 mg/kg all reduced heart rate to a similar extent during exercise at 2 and 4 h after administration; betaxolol 0.6 mg/kg had a significantly greater effect than the other treatments at all times. Only betaxolol 0.15 and 0.6 mg/kg significantly inhibited exercise tachycardia at 24 h. 3 None of the treatments studied had any effect on PEFR at rest or during exercise. 4 A second study was performed to determine whether this lack of effect of propranolol on exercise PEFR could have been due to the warm and humid conditions prevailing during the experiment. Eight healthy men underwent a standardised exercise test under alternately 'warm and humid' and 'cool and dry' conditions before and after propranolol 0.2 mg/kg or saline placebo intravenously. 5 Propranolol treatment did not influence resting or exercise PEFR in either environment, but did reduce FEV1 immediately after exercise under the cool and dry conditions but not under the warm and humid conditions. 6 Comparison of the effects of beta-adrenoceptor antagonists on exercise heart rate and PEFR is not a reliable or sensitive method of measuring the cardioselectivity of these drugs. 7 Environmental temperature and humidity should ideally be controlled when the action of any drug on airflow resistance is being studied.

Adrenergic beta-Antagonists↗

PubMed2006

Evidence for life history changes in high-altitude populations of three perennial forbs.

Relatively little is known about how the life histories of perennial forb species, and especially their lifetime patterns of growth, vary across environmental gradients. We used a post hoc approach (herb-chronology) to determine plant age and previous growth (width of successive annual rings in roots) in three species of perennial forb (two long-lived species [Penstemon venustus, Lupinus laxiflorus] and one short-lived [Rudbeckia occidentalis]) along a 1000-m altitudinal gradient in the Wallowa Mountains (northeast Oregon, USA). Plants from the highest altitude tended to be considerably older and produced up to five times as many flowering shoots as lowland plants. In addition, mean ring widths of high-altitude plants were about half those of lowland plants. In plants from low and intermediate altitudes, ring width either decreased linearly or varied inconsistently during the life of the plant. In contrast, ring widths of high-altitude plants increased at first and later decreased, resulting in curvilinear growth trajectories that were highly consistent among species. Together, these data for three ecologically distinct forb species provide evidence of a consistent shift toward more conservative and strongly constrained life histories at higher altitudes. More generally, the results indicate the possible importance of changes in selection pressures across strong environmental gradients on life history strategies within a single species.

Altitude↗

PubMed2002

Possible implications of biocide accumulation in the environment on the prevalence of bacterial antibiotic resistance.

The lethality of biocides depends upon their interaction with a number of distinct biochemical targets. This often reflects reactive chemistry for any given agent, such as thiol oxidation. Susceptibility may vary markedly between different target organisms, and changes within the more sensitive targets can alter the inhibitory effect. The multiplicity of potential targets, however, usually dictates against the development of overt resistance to concentrations used for hygienic applications. Similarly, although changes in cellular permeability toward such agents, mediated either by envelope modification or the induction of efflux-pumps may reduce susceptibility, they rarely influence the outcome of treatments at use-concentration. It has recently been proposed that chronic exposure of the environment to biocides used in a variety of commercial products might expose some microbial communities to subeffective concentrations causing emergence of resistant clones. Such resistance might relate to mutational changes in the most susceptible target or to regulatory mutants that cause the constitutive expression of certain efflux pumps. Although selection of organisms with such modifications is unlikely to influence the effectiveness of the biocides, changes in their susceptibility to third-party antibiotics can be postulated. This is particularly the case where a cellular target is shared between a biocide and an antibiotic, or where induction of efflux is sufficient to confer antibiotic resistance in the clinic. Although such linkage has been demonstrated in the laboratory in pure culture, it has not been documented in environments commonly exposed to biocides. In nature, the effects of chronic stressing with biocides are complicated by competition between microbial community members that may result in clonal expansion of naturally insusceptible clones.

Anti-Bacterial Agents↗