Techniques for the recovery and identification of Cryptosporidium oocysts from stool specimens.

Science.gov (United States)

Garcia, L S; Bruckner, D A; Brewer, T C; Shimizu, R Y

1983-07-01

Due to increasing numbers of patients with documented infections with Cryptosporidium and other coccidia, it is important for the physician and clinical laboratory to be aware of the appropriate diagnostic techniques necessary for organism recovery and identification. Although Cryptosporidium is found in the gastrointestinal tract, tissue biopsies may be insufficient for organism recovery; the examination of stool specimens is a noninvasive procedure and will provide better overall opportunities for organism recovery. Human clinical specimens were examined from 45 patients with confirmed cryptosporidiosis or suspected of having the infection. Tissue biopsy sections, fecal wet preparations, and permanent stained smears were examined. Stool specimens were submitted in 10% Formalin, 2.5% potassium dichromate, and polyvinyl alcohol and were examined for oocysts by using 15 different methods: phase-contrast and light microscopy; Sheather's sugar flotation; Formalin concentration techniques; 10% potassium hydroxide; Giemsa; trichrome; periodic acid-Schiff; modified periodic acid-Schiff; silver methenamine; acridine orange; auramine-rhodamine; Kinyoun acid-fast; Ziehl-Neelsen carbolfuchsin; and a modified acid-fast procedure. Each technique or combination of techniques was assessed by organism quantitation, organism morphology, and ease of visual recognition. Based on these comparative studies, the modified Ziehl-Neelsen carbolfuchsin stain on 10% Formalin-preserved stool is recommended for the recovery and identification of Cryptosporidium.

Working relationships of infection prevention and control programs and environmental services and associations with antibiotic-resistant organisms in Canadian acute care hospitals.

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Zoutman, Dick E; Ford, B Douglas; Sopha, Keith

2014-04-01

Environmental contamination in hospitals with antibiotic-resistant organisms (AROs) is associated with patient contraction of AROs. This study examined the working relationship of Infection Prevention and Control (IPAC) and Environmental Services and the impact of that relationship on ARO rates. Lead infection control professionals completed an online survey that assessed the IPAC and Environmental Services working relationship in their acute care hospital in 2011. The survey assessed cleaning collaborations, staff training, hospital cleanliness, and nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection, vancomycin-resistant Enterococcus (VRE) infection, and Clostridium difficile infection (CDI). The survey was completed by 58.3% of hospitals (119 of 204). Two-thirds (65.8%; 77 of 117) of the respondents reported that their cleaners were adequately trained, and 62.4% (73 of 117) reported that their hospital was sufficiently clean. Greater cooperation between IPAC and Environmental Services was associated with lower rates of MRSA infection (r = -0.22; P = .02), and frequent collaboration regarding cleaning protocols was associated with lower rates of VRE infection (r = -0.20; P = .03) and CDI (r = -0.31; P Environmental Services, and this was associated with lower rates of ARO. Deficits in the adequacy of cleaning staff training and hospital cleanliness were identified. The promotion of collaborative working relationships and additional training for Environmental Services workers would be expected to lower ARO rates. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Metabolic alterations in broiler chickens experimentally infected with sporulated oocysts of Eimeria maxima.

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Freitas, Fagner Luiz da Costa

2014-01-01

Metabolic and morphometric alterations of the duodenal villi caused by parasitism of chickens by Eimeria maxima were evaluated, using 100 male Cobb birds, randomly distributed into two groups (control and infected). The infected group was inoculated with 0.5 ml of a solution containing 5 × 10³ sporulated oocysts of Eimeria maxima. Ten birds per sample were sacrificed on the 6th, 11th, 22nd and 41st days post-infection (dpi). In order to evaluate the alterations, samples of duodenum, jejunum and ileum fragments were collected after necropsy for histological analysis. Villus biometry was determined by means of a slide graduated in microns that was attached to a binocular microscope. To evaluate the biochemical data, 5 ml of blood were sampled from the birds before sacrifice. The statistical analyses were performed using the GraphPad 5 statistical software for Windows. Tukey's multiple comparison test (p maxima causes both qualitative and quantitative alterations to the structure of the intestinal villi, thereby interfering with the absorption of nutrients such as calcium, phosphorus, magnesium, protein and lipids, with consequent reductions in the birds' weights.

Dietary leucine--an environmental modifier of insulin resistance acting on multiple levels of metabolism

DEFF Research Database (Denmark)

Macotela, Yazmin; Emanuelli, Brice; Bång, Anneli M

2011-01-01

homeostasis and insulin signaling. After 8 weeks on HFD, mice developed obesity, fatty liver, inflammatory changes in adipose tissue and insulin resistance at the level of IRS-1 phosphorylation, as well as alterations in metabolomic profile of amino acid metabolites, TCA cycle intermediates, glucose...... and cholesterol metabolites, and fatty acids in liver, muscle, fat and serum. Doubling dietary leucine reversed many of the metabolite abnormalities and caused a marked improvement in glucose tolerance and insulin signaling without altering food intake or weight gain. Increased dietary leucine was also associated......Environmental factors, such as the macronutrient composition of the diet, can have a profound impact on risk of diabetes and metabolic syndrome. In the present study we demonstrate how a single, simple dietary factor--leucine--can modify insulin resistance by acting on multiple tissues...

Impact of an Environmental Cleaning Intervention on the Presence of Methicillin-Resistant Staphylococcus aureus and Vancomycin-Resistant Enterococci on Surfaces in Intensive Care Unit Rooms

Science.gov (United States)

Goodman, Eric R.; Platt, Richard; Bass, Richard; Onderdonk, Andrew B.; Yokoe, Deborah S.; Huang, Susan S.

2009-01-01

OBJECTIVES To evaluate the adequacy of discharge room cleaning and the impact of a cleaning intervention on the presence of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) on environmental surfaces in intensive care unit (ICU) rooms. DESIGN Prospective environmental study. SETTING AND SAMPLE Convenience sample of ICU rooms in an academic hospital. METHODS AND INTERVENTION The intervention consisted of (1) a change from the use of pour bottles to bucket immersion for applying disinfectant to cleaning cloths, (2) an educational campaign, and (3) feedback regarding adequacy of discharge cleaning. Cleaning of 15 surfaces was evaluated by inspecting for removal of a preapplied mark, visible only with an ultraviolet lamp (“black light”). Six surfaces were cultured for MRSA or VRE contamination. Outcomes of mark removal and culture positivity were evaluated by χ2 testing and generalized linear mixed models, clustering by room. RESULTS The black-light mark was removed from 44% of surfaces at baseline, compared with 71% during the intervention (P <.001). The intervention increased the likelihood of removal of black-light marks after discharge cleaning (odds ratio, 4.4; P < .001), controlling for ICU type (medical vs surgical) and type of surface. The intervention reduced the likelihood of an environmental culture positive for MRSA or VRE (proportion of cultures positive, 45% at baseline vs 27% during the intervention; adjusted odds ratio, 0.4; P = .02). Broad, flat surfaces were more likely to be cleaned than were doorknobs and sink or toilet handles. CONCLUSIONS Increasing the volume of disinfectant applied to environmental surfaces, providing education for Environmental Services staff, and instituting feedback with a black-light marker improved cleaning and reduced the frequency of MRSA and VRE contamination. PMID:18624666

Concentrations of antibiotics predicted to select for resistant bacteria: Proposed limits for environmental regulation.

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Bengtsson-Palme, Johan; Larsson, D G Joakim

2016-01-01

There are concerns that selection pressure from antibiotics in the environment may accelerate the evolution and dissemination of antibiotic-resistant pathogens. Nevertheless, there is currently no regulatory system that takes such risks into account. In part, this is due to limited knowledge of environmental concentrations that might exert selection for resistant bacteria. To experimentally determine minimal selective concentrations in complex microbial ecosystems for all antibiotics would involve considerable effort. In this work, our aim was to estimate upper boundaries for selective concentrations for all common antibiotics, based on the assumption that selective concentrations a priori need to be lower than those completely inhibiting growth. Data on Minimal Inhibitory Concentrations (MICs) were obtained for 111 antibiotics from the public EUCAST database. The 1% lowest observed MICs were identified, and to compensate for limited species coverage, predicted lowest MICs adjusted for the number of tested species were extrapolated through modeling. Predicted No Effect Concentrations (PNECs) for resistance selection were then assessed using an assessment factor of 10 to account for differences between MICs and minimal selective concentrations. The resulting PNECs ranged from 8 ng/L to 64 μg/L. Furthermore, the link between taxonomic similarity between species and lowest MIC was weak. This work provides estimated upper boundaries for selective concentrations (lowest MICs) and PNECs for resistance selection for all common antibiotics. In most cases, PNECs for selection of resistance were below available PNECs for ecotoxicological effects. The generated PNECs can guide implementation of compound-specific emission limits that take into account risks for resistance promotion. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Occurrence of Cryptosporidium oocysts in Wrinkled Hornbill and other birds in the Kuala Lumpur National Zoo.

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Rohela, M; Lim, Y A L; Jamaiah, I; Khadijah, P Y Y; Laang, S T; Nazri, M H Mohd; Nurulhuda, Z

2005-01-01

The occurrence of a coccidian parasite, Cryptosporidium, among birds in the Kuala Lumpur National Zoo was investigated in this study. A hundred bird fecal samples were taken from various locations of the zoo. Fecal smears prepared using direct smear and formalin ethyl acetate concentration technique were stained with modified Ziehl-Neelsen stain. Samples positive for Cryptosporidium with Ziehl-Neelsen stain were later confirmed using the immunofluorescence technique and viewed under the epifluorescence microscope. Six species of bird feces were confirmed positive with Cryptosporidium oocysts. They included Wrinkled Hornbill (Aceros corrugatus), Great Argus Pheasant (Argusianus argus), Black Swan (Cygnus atratus), Swan Goose (Anser cygnoides), Marabou Stork (Leptoptilos crumeniferus), and Moluccan Cockatoo (Cacatua moluccencis). These birds were located in the aviary and lake, with the Moluccan Cockatoo routinely used as a show bird. Results obtained in this study indicated that animal sanctuaries like zoos and bird parks are important sources of Cryptosporidium infection to humans, especially children and other animals.

Cryptosporidium and Giardia removal by secondary and tertiary wastewater treatment.

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Taran-Benshoshan, Marina; Ofer, Naomi; Dalit, Vaizel-Ohayon; Aharoni, Avi; Revhun, Menahem; Nitzan, Yeshayahu; Nasser, Abidelfatah M

2015-01-01

Wastewater disposal may be a source of environmental contamination by Cryptosporidium and Giardia. This study was conducted to evaluate the prevalence of Cryptosporidium oocysts and Giardia cysts in raw and treated wastewater effluents. A prevalence of 100% was demonstrated for Giardia cysts in raw wastewater, at a concentration range of 10 to 12,225 cysts L(-1), whereas the concentration of Cryptosporidium oocysts in raw wastewater was 4 to 125 oocysts L(-1). The removal of Giardia cysts by secondary and tertiary treatment processes was greater than those observed for Cryptosporidium oocysts and turbidity. Cryptosporidium and Giardia were present in 68.5% and 76% of the tertiary effluent samples, respectively, at an average concentration of 0.93 cysts L(-1) and 9.94 oocysts L(-1). A higher detection limit of Cryptosporidium oocysts in wastewater was observed for nested PCR as compared to immune fluorescent assay (IFA). C. hominis was found to be the dominant genotype in wastewater effluents followed by C. parvum and C. andersoni or C. muris. Giardia was more prevalent than Cryptosporidium in the studied community and treatment processes were more efficient for the removal of Giardia than Cryptosporidium. Zoonotic genotypes of Cryptosporidium were also present in the human community. To assess the public health significance of Cryptosporidium oocysts present in tertiary effluent, viability (infectivity) needs to be assessed.

Evaluation of carriage and environmental contamination by carbapenem-resistant Acinetobacter baumannii.

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Nutman, A; Lerner, A; Schwartz, D; Carmeli, Y

2016-11-01

We evaluated the sensitivity of surveillance cultures for carbapenem-resistant Acinetobacter baumannii (CRAB) in patients and in their environment. Patients with a CRAB-positive clinical culture were sampled within 7 days; the buccal mucosa and rectum were sampled using swabs, and skin was sampled using pre-moistened sterile sponges. Sponges were also used to sample the surrounding environment. Specimens were inoculated onto CHROMagar MDR Acinetobacter plates both directly and after overnight enrichment. CRAB load was scored semi-quantitatively and composite scores for patient colonization and environmental contamination were calculated. Thirty-four patients were included. Screening sensitivity was 28/34 (82%) for buccal mucosa, 30/34 (88%) for skin, and 25/34 (74%) for rectum. Combined sensitivity was 32/34 (94%). Among patients with CRAB-positive respiratory cultures, sensitivity for buccal mucosa was 20/20 (100%). Direct inoculation had excellent sensitivity: 25/28 (89%) for all three sites combined. In the subgroup of patients who did not have a respiratory source for CRAB, direct inoculation sensitivity was lower than among patients with CRAB-positive respiratory cultures: 5/8 (63%) versus 20/20 (100%). The environment of all patients was contaminated with CRAB. There was a positive correlation between the patient colonization score and the environmental contamination score (r = 0.63, p Environmental contamination is common and can be monitored. Implementing screening may facilitate infection control efforts to limit the spread of CRAB. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

The Prehistory of Antibiotic Resistance.

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Perry, Julie; Waglechner, Nicholas; Wright, Gerard

2016-06-01

Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

Environmental Sciences Electrical resistivity soundings to determine ...

African Journals Online (AJOL)

Wood, leaves, newspaper, cloth, polythene bags, plastics, glass and metal refuse interspersed with soil exhibited resistivity of 11.6 ohm-m and layer thickness of 0.7 m as obtained from the inversion of the sounding. The unsaturated layer has a resistivity of 6.8 ohm-m and thickness of 0.6 m while leachate-saturated is ...

Haemophilus parasuis CpxRA two-component system confers bacterial tolerance to environmental stresses and macrolide resistance.

Science.gov (United States)

Cao, Qi; Feng, Fenfen; Wang, Huan; Xu, Xiaojuan; Chen, Huanchun; Cai, Xuwang; Wang, Xiangru

2018-01-01

Haemophilus parasuis is an opportunistic pathogen localized in the upper respiratory tracts of pigs, its infection begins from bacterial survival under complex conditions, like hyperosmosis, oxidative stress, phagocytosis, and sometimes antibiotics as well. The two-component signal transduction (TCST) system serves as a common stimulus-response mechanism that allows microbes to sense and respond to diverse environmental conditions via a series of phosphorylation reactions. In this study, we investigated the role of TCST system CpxRA in H. parasuis in response to different environmental stimuli by constructing the ΔcpxA and ΔcpxR single deletion mutants as well as the ΔcpxRA double deletion mutant from H. parasuis serotype 4 isolate JS0135. We demonstrated that H. parasuis TCST system CpxRA confers bacterial tolerance to stresses and bactericidal antibiotics. The CpxR was found to play essential roles in mediating oxidative stress, osmotic stresses and alkaline pH stress tolerance, as well as macrolide resistance (i.e. erythromycin), but the CpxA deletion did not decrease bacterial resistance to abovementioned stresses. Moreover, we found via RT-qPCR approach that HAPS_RS00160 and HAPS_RS09425, both encoding multidrug efflux pumps, were significantly decreased in erythromycin challenged ΔcpxR and ΔcpxRA mutants compared with wild-type strain JS0135. These findings characterize the role of the TCST system CpxRA in H. parasuis conferring stress response tolerance and bactericidal resistance, which will deepen our understanding of the pathogenic mechanism in H. parasuis. Copyright © 2017 Elsevier GmbH. All rights reserved.

Diagnostic value of a Rec-ELISA using Toxoplasma gondii recombinant SporoSAG, BAG1, and GRA1 proteins in murine models infected orally with tissue cysts and oocysts.

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Mert Döşkaya

Full Text Available Toxoplasma gondii causes congenital toxoplasmosis in newborns resulting with fetal anomalies. Determining the initiation time of infection is very important for pregnant women and current serological assays have drawbacks in distinguishing the recently acute toxoplasmosis. Diagnosis of recently acute infection may be improved by using stage specific antigens in serological assays. In the present study, the diagnostic value of sporozoite specific SporoSAG, bradyzoite specific BAG1 proteins and GRA1 protein expressed by all forms of the parasite have been evaluated ELISA using sera systematically collected from mice administered orally with tissue cyst and oocysts. The anti-SporoSAG IgM antibodies in sera obtained from mice infected with oocysts peaked significantly at days 1, 10, and 15 (P<0.01. The anti-BAG1 IgM antibodies in sera obtained from mice infected with tissue cysts peaked significantly at days 15, 40, and 120 (P<0.05. The anti-GRA1 IgM antibodies in sera obtained from mice infected with oocysts peaked significantly at days 2, 10, and 40 (P<0.01. The anti-GRA1 IgM antibodies in sera obtained from mice infected with tissue cysts peaked significantly only at day 40 (P<0.05. The anti-SporoSAG, anti-BAG1, and anti-GRA1 IgG titers of mice showed significant increases at day 40 (P<0.05 and decrement started for only anti-GRA1 IgG at day 120. The presence of anti-SporoSAG IgM and IgG antibodies can be interpreted as recently acute infection between days 10-40 because IgM decreases at day 40. Similarly, presence of anti-BAG1 IgM and absence of IgG can be evaluated as a recently acute infection that occurred 40 days before because IgG peaks at day 40. A peak in anti-GRA1 antibody level at first testing and reduction in consecutive sample can be considered as an infection approximately around day 40 or prior. Overall, recombinant SporoSAG, BAG1 and GRA1 proteins can be accepted as valuable diagnostic markers of recently acute toxoplasmosis.

Environmental colonization and onward clonal transmission of carbapenem-resistant Acinetobacter baumannii (CRAB) in a medical intensive care unit: the case for environmental hygiene.

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Ng, Deborah H L; Marimuthu, Kalisvar; Lee, Jia Jun; Khong, Wei Xin; Ng, Oon Tek; Zhang, Wei; Poh, Bee Fong; Rao, Pooja; Raj, Maya Devi Rajinder; Ang, Brenda; De, Partha Pratim

2018-01-01

In May 2015, we noticed an increase in carbapenem-resistant Acinetobacter baumannii (CRAB) infections in the Medical Intensive Care Unit (MICU). To investigate this, we studied the extent of environmental contamination and subsequent onward clonal transmission of CRAB. We conducted a one-day point prevalence screening (PPS) of the patients and environment in the MICU. We screened patients using endotracheal tube aspirates and swabs from nares, axillae, groin, rectum, wounds, and exit sites of drains. We collected environmental samples from patients' rooms and environment outside the patients' rooms. CRAB isolates from the PPS and clinical samples over the subsequent one month were studied for genetic relatedness by whole genome sequencing (WGS). We collected 34 samples from seven patients and 244 samples from the environment. On the day of PPS, we identified 8 CRAB carriers: 3 who screened positive and 5 previously known clinical infections. We detected environmental contamination in nearly two-thirds of the rooms housing patients with CRAB. WGS demonstrated genetic clustering of isolates within rooms but not across rooms. We analysed 4 CRAB isolates from clinical samples following the PPS. One genetically-related CRAB was identified in the respiratory sample of a patient with nosocomial pneumonia, who was admitted to the MICU five days after the PPS. The extensive environmental colonization of CRAB by patients highlights the importance of environmental hygiene. The transmission dynamics of CRAB needs further investigation.

Lifespan extension and increased resistance to environmental stressors by N-Acetyl-L-Cysteine in Caenorhabditis elegans

Directory of Open Access Journals (Sweden)

Seung-Il Oh

2015-05-01

Full Text Available OBJECTIVE: This study was performed to determine the effect of N-acetyl-L-cysteine, a modified sulfur-containing amino acid that acts as a strong cellular antioxidant, on the response to environmental stressors and on aging in C. elegans. METHOD: The survival of worms under oxidative stress conditions induced by paraquat was evaluated with and without in vivo N-acetyl-L-cysteine treatment. The effect of N-acetyl-L-cysteine on the response to other environmental stressors, including heat stress and ultraviolet irradiation (UV, was also monitored. To investigate the effect on aging, we examined changes in lifespan, fertility, and expression of age-related biomarkers in C. elegans after N-acetyl-L-cysteine treatment. RESULTS: Dietary N-acetyl-L-cysteine supplementation significantly increased resistance to oxidative stress, heat stress, and UV irradiation in C. elegans. In addition, N-acetyl-L-cysteine supplementation significantly extended both the mean and maximum lifespan of C. elegans. The mean lifespan was extended by up to 30.5% with 5 mM N-acetyl-L-cysteine treatment, and the maximum lifespan was increased by 8 days. N-acetyl-L-cysteine supplementation also increased the total number of progeny produced and extended the gravid period of C. elegans. The green fluorescent protein reporter assay revealed that expression of the stress-responsive genes, sod-3 and hsp-16.2, increased significantly following N-acetyl-L-cysteine treatment. CONCLUSION: N-acetyl-L-cysteine supplementation confers a longevity phenotype in C. elegans, possibly through increased resistance to environmental stressors.

Seroprevalence of Toxoplasma gondii and Neospora caninum in feral cats (Felis silvestris catus) in Majorca, Balearic Islands, Spain.

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Millán, Javier; Cabezón, Oscar; Pabón, Marcela; Dubey, J P; Almería, Sonia

2009-11-12

Felids are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete environmentally resistant oocysts. Antibodies to T. gondii and Neospora caninum were determined in serum samples from 59 feral cats (Felis silvestris catus) captured in baited traps during authorized predator control campaigns in Majorca, Balearic Islands, Spain. Antibodies to T. gondii assayed by the modified agglutination test (MAT) were found in 50 (84.7%) of 59 cats with MAT titers of 1:25 in one cat, 1:200 in four cats, 1:500 in seven cats, 1:1000 in nine cats, and >or=1:2000 in 29 cats. Seroprevalence (MAT, 1:25 or more) was significantly higher in adults (94.6%) than in juveniles (cats in Majorca is one of the highest reported worldwide in this species and the highest observed in Europe to date. The results suggest that feral cats in Majorca have a high rate of T. gondii infection with important implications for public health on the island since the seropositive cats are likely to have already shed T. gondii oocysts in the environment.

Efficacy of a hospital-wide environmental cleaning protocol on hospital-acquired methicillin-resistant Staphylococcus aureus rates.

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Watson, Paul Andrew; Watson, Luke Robert; Torress-Cook, Alfonso

2016-07-01

Environmental contamination has been associated with over half of methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in hospitals. We explored if a hospital-wide environmental and patient cleaning protocol would lower hospital acquired MRSA rates and associated costs. This study evaluates the impact of implementing a hospital-wide environmental and patient cleaning protocol on the rate of MRSA infection and the potential cost benefit of the intervention. A retrospective, pre-post interventional study design was used. The intervention comprised a combination of enhanced environmental cleaning of high touch surfaces, daily washing of patients with benzalkonium chloride, and targeted isolation of patients with active infection. The rate of MRSA infection per 1000 patient days (PD) was compared with the rate after the intervention (Steiros Algorithm ® ) was implemented. A cost-benefit analysis based on the number of MRSA infections avoided was conducted. The MRSA rates decreased by 96% from 3.04 per 1000 PD to 0.11 per 1000 PD ( P reduction in MRSA infections, avoided an estimated $1,655,143 in healthcare costs. Implementation of this hospital-wide protocol appears to be associated with a reduction in the rate of MRSA infection and therefore a reduction in associated healthcare costs.

Providing context: antimicrobial resistance from multiple environmental sources

Science.gov (United States)

Background: Animal agriculture has been identified as encouraging the spread of resistance due to the use of large quantities of antimicrobials for animal production purposes. When antimicrobial resistance (AMR) is reported in agricultural settings without comparison to other environments there is a...

Ante-mortem diagnosis, diarrhea, oocyst shedding, treatment, isolation, and genetic typing of Toxoplasma gondii associated with clinical toxoplasmosis in a naturally infected cat.

Science.gov (United States)

Dubey, J P; Prowell, M

2013-02-01

Toxoplasma gondii infections are common in humans and other animals, but clinical disease is relatively rare. It is unknown whether the severity of toxoplasmosis in immunocompetent hosts is due to the parasite strain, host variability, or to other factors. Recently, attention has been focused on the genetic variability among T. gondii isolates from apparently healthy and sick hosts. Whether T. gondii genetic makeup plays a part in the pathogenesis of clinical feline toxoplasmosis is uncertain because little is known of genetic typing of strains associated with clinical feline toxoplasmosis. A 6-mo-old domestic male cat was hospitalized because of lethargy, anorexia, fever, and diarrhea. Numerous (6 million in 1 sample) T. gondii oocysts were found in feces of the cat and antibodies to T. gondii (titer 1:800) were found in its serum by the modified agglutination test. The cat was medicated orally with Clindamycin for 10 days; it became asymptomatic after 10 days and was discharged from the hospital. Viable T. gondii (designated TgCatUs9) was isolated from feces (oocysts) by bioassays in mice. Genetic typing using the DNA extracted from the brains of infected mice and 10 PCR-restriction fragment length polymorphism (RFLP) markers revealed Type II allele at the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, and PK1 loci and Type I at the L358 and Apico loci; therefore, this isolate belongs to the ToxoDB PCR-RFLP genotype no. 4, which is grouped into the Type 12 lineage that is dominant in wildlife from North America. To our knowledge, this is the first T. gondii isolate characterized genetically from a sick cat in the USA.

Mutation of environmental mycobacteria to resist silver nanoparticles also confers resistance to a common antibiotic.

Science.gov (United States)

Larimer, Curtis; Islam, Mohammad Shyful; Ojha, Anil; Nettleship, Ian

2014-08-01

Non-tuberculous mycobacteria are a threat to human health, gaining entry to the body through contaminated water systems, where they form persistent biofilms despite extensive attempts at disinfection. Silver is a natural antibacterial agent and in nanoparticle form activity is increased by a high surface area. Silver nanoparticles (AgNPs) have been used as alternative disinfectants in circulating water systems, washing machines and even clothing. However, nanoparticles, like any other antibiotic that has a pervasive durable presence, carry the risk of creating a resistant population. In this study Mycobacterium smegmatis strain mc(2)155 was cultured in AgNP enriched agar such that only a small population survived. Surviving cultures were isolated and re-exposed to AgNPs and AgNO3 and resistance to silver was compared to a negative control. After only a single exposure, mutant M. smegmatis populations were resistant to AgNPs and AgNO3. Further, the silver resistant mutants were exposed to antibiotics to determine if general resistance had been conferred. The minimum inhibitory concentration of isoniazid was four times higher for silver resistant mutants than for strain mc(2)155. However, core resistance was not conferred to other toxic metal ions. The mutants had lower resistance to CuSO4 and ZnSO4 than the mc(2)155 strain.

Antimicrobial susceptibility and antibiotic resistance gene transfer analysis of foodborne, clinical, and environmental Listeria spp. isolates including Listeria monocytogenes.

Science.gov (United States)

Bertsch, David; Muelli, Mirjam; Weller, Monika; Uruty, Anaïs; Lacroix, Christophe; Meile, Leo

2014-02-01

The aims of this study were to assess antibiotic resistance pheno- and genotypes in foodborne, clinical, and environmental Listeria isolates, as well as to elucidate the horizontal gene transfer potential of detected resistance genes. A small fraction of in total 524 Listeria spp. isolates (3.1%) displayed acquired antibiotic resistance mainly to tetracycline (n = 11), but also to clindamycin (n = 4) and trimethoprim (n = 3), which was genotypically confirmed. In two cases, a tetracycline resistance phenotype was observed together with a trimethoprim resistance phenotype, namely in a clinical L. monocytogenes strain and in a foodborne L. innocua isolate. Depending on the applied guidelines, a differing number of isolates (n = 2 or n = 20) showed values for ampicillin that are on the edge between intermediate susceptibility and resistance. Transferability of the antibiotic resistance genes from the Listeria donors, elucidated in vitro by filter matings, was demonstrated for genes located on transposons of the Tn916 family and for an unknown clindamycin resistance determinant. Transfer rates of up to 10(-5) transconjugants per donor were obtained with a L. monocytogenes recipient and up to 10(-7) with an Enterococcus faecalis recipient, respectively. Although the prevalence of acquired antibiotic resistance in Listeria isolates from this study was rather low, the transferability of these resistances enables further spread in the future. This endorses the importance of surveillance of L. monocytogenes and other Listeria spp. in terms of antibiotic susceptibility. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Human Coronaviruses: Insights into Environmental Resistance and Its Influence on the Development of New Antiseptic Strategies

Science.gov (United States)

Geller, Chloé; Varbanov, Mihayl; Duval, Raphaël E.

2012-01-01

The Coronaviridae family, an enveloped RNA virus family, and, more particularly, human coronaviruses (HCoV), were historically known to be responsible for a large portion of common colds and other upper respiratory tract infections. HCoV are now known to be involved in more serious respiratory diseases, i.e. bronchitis, bronchiolitis or pneumonia, especially in young children and neonates, elderly people and immunosuppressed patients. They have also been involved in nosocomial viral infections. In 2002–2003, the outbreak of severe acute respiratory syndrome (SARS), due to a newly discovered coronavirus, the SARS-associated coronavirus (SARS-CoV); led to a new awareness of the medical importance of the Coronaviridae family. This pathogen, responsible for an emerging disease in humans, with high risk of fatal outcome; underline the pressing need for new approaches to the management of the infection, and primarily to its prevention. Another interesting feature of coronaviruses is their potential environmental resistance, despite the accepted fragility of enveloped viruses. Indeed, several studies have described the ability of HCoVs (i.e. HCoV 229E, HCoV OC43 (also known as betacoronavirus 1), NL63, HKU1 or SARS-CoV) to survive in different environmental conditions (e.g. temperature and humidity), on different supports found in hospital settings such as aluminum, sterile sponges or latex surgical gloves or in biological fluids. Finally, taking into account the persisting lack of specific antiviral treatments (there is, in fact, no specific treatment available to fight coronaviruses infections), the Coronaviridae specificities (i.e. pathogenicity, potential environmental resistance) make them a challenging model for the development of efficient means of prevention, as an adapted antisepsis-disinfection, to prevent the environmental spread of such infective agents. This review will summarize current knowledge on the capacity of human coronaviruses to survive in the

Integrated electromagnetic (EM) and Electrical Resistivity Tomography (ERT) geophysical studies of environmental impact of Awotan dumpsite in Ibadan, southwestern Nigeria

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Osinowo, Olawale Olakunle; Falufosi, Michael Oluseyi; Omiyale, Eniola Oluwatosin

2018-04-01

This study attempts to establish the level of contamination caused by the decomposition of wastes by defining the lateral distribution and the vertical limit of leachate induced zone of anomalous conductivity distribution within the subsurface through the analyses of Electromagnetic (EM) and Electrical Resistivity Tomography (ERT) data, generated from the integrated geophysical survey over Awotan landfill dumpsite, in Ibadan, southwest Nigeria. Nine (9) EM and ERT profiles each were established within and around the Awotan landfill site. EM data were acquire at 5 m station interval using 10 m, 20 m and 40 m inter-coil spacings, while ERT stations were occupied at 2 m electrode spacing using dipole-dipole electrode configuration. The near perfect agreement between the two sets of data generated from the EM and ERT surveys over the Awotan landfill site as well as the subsurface imaging ability of these geophysical methods to delineate the region of elevated contamination presented in the form of anomalously high apparent ground conductivity and low subsurface resistivity distribution, suggest the importance of integrating electromagnetic and electrical resistivity investigation techniques for environmental studies and more importantly for selecting appropriate landfill dump site location such with ability to retain the generated contaminants and thus prevent environmental pollution.

Resistência antimicrobiana em Salmonella Enteritidis isoladas de amostras clínicas e ambientais de frangos de corte e matrizes pesadas Antimicrobial resistance in Salmonella Enteritidis isolated from clinical and environmental broiler chickens and breeders broiler

Directory of Open Access Journals (Sweden)

A.R. Ribeiro

2008-10-01

Full Text Available The antimicrobial resistance of Salmonella Enteritidis strains isolated from clinical and environmental poultry samples in the Southern Brazil during the years of 1999, 2000 and 2001 was evaluated. Among the 79 isolated samples, 64 (81% were resistant to at least one of the antimicrobial agents tested, showing 22 different resistance patterns. Tetracycline showed the highest percentage (64,5% of resistance among the antimicrobial agents used. Resistance to drugs at different levels was found as the following: ampicillin (1.2%, kanamycin (1.2%, ciprofloxacin (2.5%, enrofloxacin (8.8%, gentamicin (21.5%, streptomycin (20.2%, nitrofurantoin (26.6%, and nalidixic acid (30.4%. None of the S. Enteritidis strains were resistant to chloramphenicol, norfloxacin, and polimycin B. Among the 64 S. Enteritidis strains that showed resistance, 43 (67.2% were resistant to two or more antimicrobial agents. Twenty-one (32.8% strains were resistant to only one of the antimicrobial agents, 14 to tetracycline, three to nalidixic acid, three to nitrofurantoin, and one to gentamycin. These antimicrobial resistance levels suggest a high occurrence of tetracycline resistant S. Enteritidis strains and resistance to two or more antimicrobial agents.

A molecular epidemiological study of methicillin-resistant Staphylococci environmental contamination in railway stations and coach stations in Guangzhou of China.

Science.gov (United States)

Lin, J L; Peng, Y; Ou, Q T; Lin, D X; Li, Y; Ye, X H; Zhou, J L; Yao, Z J

2017-02-01

Methicillin-resistant Staphylococcus aureus (MRSA) has caused a series of public health problems since it was first found in 1961. However, there are few research studies on the MRSA environmental contamination in railway stations and coach stations. Therefore, the aim of this study was to determine MRSA environmental contamination in public transport stations. Between December 2013 and January 2014, 380 surface samples from three railway stations (180) and four coach stations (200) in Guangzhou were collected to isolate and determine the prevalence and characteristics of Staphylococci strains. 39·21% of all samples were Staphylococci isolates, 1·58% of Staphylococci isolates were MRSA isolates, and 6·05% were methicillin-susceptible S. aureus. The proportion of multidrug resistant among 149 Staphylococci isolates was 75·84%. None of MRSA isolates was identified with the Panton-Valentine Leukocidin (PVL) genes, and one of them was identified with the qac gene. Four MRSA isolates were Staphylococcal Cassette Chromosome mec IVa, and the other two were nontypeable. Staphylococcus aureus isolates were classified into several sequence types (STs), and STs showed possible cross-transmissions of isolates from various sources. Methicillin-resistant Staphylococci contamination prevalence was high, and the environment of stations may be the vectors transmitting the Staphylococci to passengers. This is the first study to comprehensively report the prevalence, antibiotic resistance, and molecular characteristics of contamination of Staphylococci isolates in railway stations and coach stations of China. It will have great public health implications on infection control in community settings because of the serious hazard of Staphylococci, especially methicillin-resistant Staphylococci. Our findings have provided evidence for relevant departments to reduce the contamination of Staphylococci in environment of public transport stations. © 2016 The Society for Applied

Studying the Relationship between the Ability of Biofilm Formation and Antibiotic Resistance in Acinetobacter baumannii Clinical and Environmental Isolates in Tehran, 2015

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Faegheh Teymori

2017-07-01

Full Text Available Abstract Background: Acinetobacters are aerobic gram-negative bacteria which are distributed widespread in soil and water. The bacteria are isolated from cultured skin, mucous membranes, secretions and hospital environment. Acinetobacter baumannii, is a strain that more frequently isolated. Acinetobacter strains are often resistant against antimicrobial agents. Materials and Methods: The method of this study was based on field, observation and test. On August and October 2015, samples were isolated from the soil and water of the Sadeghieh Square river in Tehran, respectively, and were transferred to the laboratory in the ice pack. 50 baumannii samples were isolated by biochemical methods (TSI, SIM, OF and gram test. November 1394, 100 clinical samples were isolated from Imam Khomeini hospital by biochemical method, and in the culture media Mueller Hinton agar plates were transferred to the laboratory. Antibiogram test for 150 baumannii samples was performed. Biofilms formation of Acinetobacter baumannii environmental and clinical samples was investigated by Congo red agar and culture plate methods. Results: In all samples (clinical and soil, most of antibiotic resistance was 92% for imipenem and the resistance of water samples to imipenem was 99.9%. Biofilm formation by Congo red agar in water, soil, and clinical samles was resprctively 44%, 40% and 1%. All isolates were negative biofilm culture plate. Conclusion: Considering Acinetobacter baumannii resistance to antibiotics and the lack of biofilm formation of in clinical and environmental isolates, it was concluded that there wasn’t any relationship between antibiotic resistance and biofilm formation.

Effects of vaccination against coccidiosis, with and without a specific herbal essential oil blend, on performance, oocyst excretion and serum IBD titers of broilers reared on litter

Directory of Open Access Journals (Sweden)

Mustafa Çınar

2012-01-01

Full Text Available The aim of the present experiment was to investigate the effects of oral administration of a live attenuated vaccine (VAC and an essential oil blend (EOB, either alone or in combination, as a novel anticoccidial strategy for broiler chickens with a mixed Eimeria spp. infection. A total of 624 broiler chicks were randomly assigned to one of six treatments. Two of the groups, only one of which was challenged with coccidiosis, were given a basal diet and served as controls. The other two groups, also infected, were given a basal diet supplemented with monensin sodium (MON, 100 mg/kg or the EOB (75 mg/kg. Of the remaining two groups, which were infected with coccidiosis, one was vaccinated against coccidiosis (VAC and the other was both vaccinated and fed a diet with an EOB (VAC+EOB. Birds treated with VAC and VAC+EOB had comparable live performance to MON-fed birds challenged with coccidiosis. Conversely, EOB diet supplementation had negative effects on growth, feed intake and feed conversion ratio throughout the growth period. None of the coccidial control strategies affected the overall performance of uninfected birds. There was no significant difference in mortality among treatments. All of the anticoccidial procedures kept serum infectious bursal disease titers at high levels after coccidial infection and reduced fecal oocyst excretion, with the exception of the MON-based procedure. The results indicate that vaccination against coccidiosis, with or without EOB, demonstrated the same efficacy in promoting recovery from coccidial infection and in reducing oocyst shedding as MON.

Genetic and environmental relationships between change in weight and insulin resistance: the Healthy Twin Study.

Science.gov (United States)

Song, Yun-Mi; Lee, Kayoung; Sung, Joohon

2014-06-01

We aimed to investigate the association between weight change from 20 years of age and insulin resistance (IR), and genetic and environmental relationships between these traits. In 594 Korean twins and family members (209 men, 385 women, 44.0 ± 10.8 years old), the percentage of weight change was calculated using self-reported body weight at 20 years of age and currently measured bodyweight. IR traits were assessed using fasting plasma glucose and insulin, the homeostasis model assessment of IR index (HOMA-IR), and the quantitative insulin sensitivity check index (QUICKI). Linear mixed analysis was applied after adjusting for household, body mass index (BMI) at the age of 20 years, age, sex, alcohol, smoking, physical activity, and caloric intake. Heritabilities and genetic and environmental correlations were estimated after adjusting for covariates. In 55 monozygotic twin pairs discordant for HOMA-IR level by >0.3, a conditional logistic regression analysis was conducted regarding weight change. Increases in glucose, insulin, and HOMA-IR and a decrease in QUICKI were associated with a higher percentage of weight change (p change since 20 years old, after adjusting for lifestyle-related factors. In conclusion, both genetic and environmental influences played significant roles in the positive association between weight change from 20 years of age and IR.

Control of a Clonal Outbreak of Multidrug-Resistant Acinetobacter baumannii in a Hospital of the Basque Country after the Introduction of Environmental Cleaning Led by the Systematic Sampling from Environmental Objects.

Science.gov (United States)

Delgado Naranjo, Jesús; Villate Navarro, José Ignacio; Sota Busselo, Mercedes; Martínez Ruíz, Alberto; Hernández Hernández, José María; Torres Garmendia, María Pilar; Urcelay López, María Isabel

2013-01-01

Background. Between July 2009 and September 2010, an outbreak of multidrug-resistant (MDR) Acinetobacter baumannii was detected in one critical care unit of a tertiary hospital in the Basque Country, involving 49 infected and 16 colonized patients. The aim was to evaluate the impact of environmental cleaning and systematic sampling from environmental objects on the risk of infection by MDR A. baumannii. Methods. After systematic sampling from environmental objects and molecular typing of all new MDR A. baumannii strains from patients and environmental isolates, we analyzed the correlation (Pearson's r) between new infected cases and positive environmental samples. The risk ratio (RR) of infection was estimated with Poisson regression. Results. The risk increased significantly with the number of positive samples in common areas (RR = 1.40; 95%CI = 0.99-1.94) and positive samples in boxes (RR = 1.19; 95%CI = 1.01-1.40). The number of cases also positively correlated with positive samples in boxes (r = 0.50; P systematic sampling from environmental objects, provided the objective risk reduction of new cases and enabled the full control of the outbreak.

Identification of a Plasmid-Mediated Quinolone Resistance Gene in Salmonella Isolates from Texas Dairy Farm Environmental Samples.

Science.gov (United States)

Cummings, K J; Rodriguez-Rivera, L D; Norman, K N; Ohta, N; Scott, H M

2017-06-01

A recent increase in plasmid-mediated quinolone resistance (PMQR) has been detected among Salmonella isolated from humans in the United States, and it is necessary to determine the sources of human infection. We had previously isolated Salmonella from dairy farm environmental samples collected in Texas, and isolates were tested for anti-microbial susceptibility. Two isolates, serotyped as Salmonella Muenster, showed the discordant pattern of nalidixic acid susceptibility and intermediate susceptibility to ciprofloxacin. For this project, whole-genome sequencing of both isolates was performed to detect genes associated with quinolone resistance. The plasmid-mediated qnrB19 gene and IncR plasmid type were identified in both isolates. To our knowledge, this is the first report of PMQR in Salmonella isolated from food animals or agricultural environments in the United States. © 2016 Blackwell Verlag GmbH.

ASSESSMENT OF IMPACT OF COHERENT LIGHT ON RESISTANCE OF PLANTS GROWING IN UNFAVOURABLE ENVIRONMENTAL CONDITIONS

Directory of Open Access Journals (Sweden)

Małgorzata Śliwka

2014-04-01

Full Text Available The results of experiments on the effect of the coherent light emitted by lasers on plant material show that properly selected laser stimulation parameters, such as: wavelength, power, time and type of exposure, allow to obtain a greater growth of plant biomass, changes in the content of elements in the biomass and increasing plant resistance to unfavorable environmental conditions. The aim of this study was to determine the effect of laser stimulation on selected plant species (Iris pseudoacorus L., Lemna minor L. to increase their resistance to low temperatures and the ability to adapt to an environment polluted by mining activities (Phelum pratense L.. Plants from experimental groups (Iris pseudoacorus L., Phelum pratense L., Lemna minor L. were stimulated with coherent light with specific characteristics. To irradiate plants from experimental groups different algorithms of stimulation parameters, differentiating the method and time of exposure were used. Plants group without the stimulation, were the reference group. The article discusses the results of preliminary experiments carried out on a laboratory scale and pot experiments.

Improved annotation of antibiotic resistance determinants reveals microbial resistomes cluster by ecology.

Science.gov (United States)

Gibson, Molly K; Forsberg, Kevin J; Dantas, Gautam

2015-01-01

Antibiotic resistance is a dire clinical problem with important ecological dimensions. While antibiotic resistance in human pathogens continues to rise at alarming rates, the impact of environmental resistance on human health is still unclear. To investigate the relationship between human-associated and environmental resistomes, we analyzed functional metagenomic selections for resistance against 18 clinically relevant antibiotics from soil and human gut microbiota as well as a set of multidrug-resistant cultured soil isolates. These analyses were enabled by Resfams, a new curated database of protein families and associated highly precise and accurate profile hidden Markov models, confirmed for antibiotic resistance function and organized by ontology. We demonstrate that the antibiotic resistance functions that give rise to the resistance profiles observed in environmental and human-associated microbial communities significantly differ between ecologies. Antibiotic resistance functions that most discriminate between ecologies provide resistance to β-lactams and tetracyclines, two of the most widely used classes of antibiotics in the clinic and agriculture. We also analyzed the antibiotic resistance gene composition of over 6000 sequenced microbial genomes, revealing significant enrichment of resistance functions by both ecology and phylogeny. Together, our results indicate that environmental and human-associated microbial communities harbor distinct resistance genes, suggesting that antibiotic resistance functions are largely constrained by ecology.

Antibacterial resistance: an emerging 'zoonosis'?

Science.gov (United States)

Labro, Marie-Thérèse; Bryskier, Jean-Marie

2014-12-01

Antibacterial resistance is a worldwide threat, and concerns have arisen about the involvement of animal commensal and pathogenic bacteria in the maintenance and spread of resistance genes. However, beyond the facts related to the occurrence of resistant microorganisms in food, food-producing animals and companion animals and their transmission to humans, it is important to consider the vast environmental 'resistome', the selective pathways underlying the emergence of antibacterial resistance and how we can prepare answers for tomorrow.

Drug Pollution from Manufacturing and Antimicrobial Resistance: How Does the European Union Manage the Potential Environmental and Health Risks of Importing Pharmaceutical Active Ingredients From Third Countries?

DEFF Research Database (Denmark)

le Gal, Elodie Jeanine Odette

pollution and anti-micro-bacterial resistance within their own borders by buying and importing drugs manufactured in third countries, such as India and China. With a focus on drug pollution from manufacturing, the goal of this paper is to explore the European drug import safety regime. It intends to better...... and environmental failures. Over the past three decades, the scientific literature has been increasingly reporting case studies on environmental pollution from drug manufacturing, human excretions and improper disposal of unused or expired drug residues in different parts of the world. Active ingredients, which...... are responsible for the biological activity of drugs, have been identified as the main vector of pharmaceutical pollution. Associated with the environmental risk of pharmaceutical pollution in soils and waterways is the predicted risk of antimicrobial resistance (AMR) expected to increase and to dramatically...

Electrical resistance tomography used in environmental restoration

International Nuclear Information System (INIS)

Ramirez, A.L.; Daily, W.; LaBrecque, D.

1992-04-01

We are developing a new imaging technique, Electrical Resistance Tomography (ERT), to map subsurface liquids as flow occurs during natural or clean-up processes; ERT can also be used to map geologic structure. Natural processes (such as surface water infiltrating the vadose zone) and clean-up processes (such as air injection in the saturated zone, steam injection, emplacement of subsurface barriers) can create changes in a soil's electrical properties that are readily measured. We use these measurements to calculate tomographs that show the spatial distribution of the subsurface resistivities. The information derived from ERT can be used by remediation projects to: monitor the effectiveness of clean-up processes, characterize hydrologic processes affecting contaminant transport, select appropriate clean-up alternatives, demonstrate regulatory compliance, and to verify the installation and performance of subsurface barriers

Faecal helminth egg and oocyst counts of a small population of African lions (Panthera leo in the southwestern Kalahari, Namibia : research communication

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Y. Smith

2006-09-01

Full Text Available An endoparasite survey of a small pride of African lions (Panthera leo was conducted at Intu Afrika Kalahari Game Reserve, southwestern Namibia, during winter and summer of 2003 and 2004, respectively. Overall, 23 fresh lion scats were collected opportunistically during fieldwork trials. A flotation technique was employed for the diagnosis of parasites. Three nematodes, Ancylostoma braziliense, Gnathostoma spinigerum and Uncinaria stenocephala and two coccidians, Toxoplasma gondii and Isospora felis were recorded. By using the McMaster method for quantification, a maximum number of 14 866 oocysts per gram of faeces was obtained for I. felis during winter 2003. Endoparasite taxa carried by the different individuals in the pride were found to be related to their levels of association. Rates of infection were relatively low as a result of the habitat, semi-captive conditions and earlier sporadic deworming.

Recombinase polymerase amplification (RPA) combined with lateral flow (LF) strip for detection of Toxoplasma gondii in the environment.

Science.gov (United States)

Wu, Y D; Xu, M J; Wang, Q Q; Zhou, C X; Wang, M; Zhu, X Q; Zhou, D H

2017-08-30

Toxoplasma gondii infects all warm-blooded vertebrates, resulting in a great threat to human health and significant economic loss to the livestock industry. Ingestion of infectious oocysts of T. gondii from the environment is the major source of transmission. Detection of T. gondii oocysts by existing methods is laborious, time-consuming and expensive. The objective of the present study was to develop a recombinase polymerase amplification (RPA) method combined with a lateral flow (LF) strip for detection of T. gondii oocysts in the soil and water. The DNA of T. gondii oocysts was amplified by a pair of specific primers based on the T. gondii B1 gene over 15min at a constant temperature ranging from 30°C to 45°C using RPA. The amplification product was visualized by the lateral flow (LF) strip within 5min using the specific probe added to the RPA reaction system. The sensitivity of the established assay was 10 times higher than that of nested PCR with a lower detection limit of 0.1 oocyst per reaction, and there was no cross-reactivity with other closely related protozoan species. Fifty environmental samples were further assessed for the detection validity of the LF-RPA assay (B1-LF-RPA) and compared with nested PCR based on the B1 gene sequence. The B1-LF-RPA and nested PCR both showed that 5 out of the 50 environmental samples were positive. The B1-LF-RPA method was also proven to be sufficiently tolerant of existing inhibitors in the environment. In addition, the advantages of simple operation, speediness and cost-effectiveness make B1-LF-RPA a promising molecular detection tool for T. gondii. Copyright © 2017 Elsevier B.V. All rights reserved.

Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

Science.gov (United States)

Hong, Pei-Ying; Al-Jassim, Nada; Ansari, Mohd Ikram; Mackie, Roderick I.

2013-01-01

Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water. PMID:27029309

Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

Directory of Open Access Journals (Sweden)

Roderick I. Mackie

2013-07-01

Full Text Available Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

KAUST Repository

Hong, Pei-Ying; Aljassim, Nada I.; Ansari, Mohd Ikram; Mackie, Roderick

2013-01-01

Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

Environmental and Public Health Implications of Water Reuse: Antibiotics, Antibiotic Resistant Bacteria, and Antibiotic Resistance Genes

KAUST Repository

Hong, Pei-Ying

2013-07-31

Water scarcity is a global problem, and is particularly acute in certain regions like Africa, the Middle East, as well as the western states of America. A breakdown on water usage revealed that 70% of freshwater supplies are used for agricultural irrigation. The use of reclaimed water as an alternative water source for agricultural irrigation would greatly alleviate the demand on freshwater sources. This paradigm shift is gaining momentum in several water scarce countries like Saudi Arabia. However, microbial problems associated with reclaimed water may hinder the use of reclaimed water for agricultural irrigation. Of particular concern is that the occurrence of antibiotic residues in the reclaimed water can select for antibiotic resistance genes among the microbial community. Antibiotic resistance genes can be associated with mobile genetic elements, which in turn allow a promiscuous transfer of resistance traits from one bacterium to another. Together with the pathogens that are present in the reclaimed water, antibiotic resistant bacteria can potentially exchange mobile genetic elements to create the “perfect microbial storm”. Given the significance of this issue, a deeper understanding of the occurrence of antibiotics in reclaimed water, and their potential influence on the selection of resistant microorganisms would be essential. In this review paper, we collated literature over the past two decades to determine the occurrence of antibiotics in municipal wastewater and livestock manure. We then discuss how these antibiotic resistant bacteria may impose a potential microbial risk to the environment and public health, and the knowledge gaps that would have to be addressed in future studies. Overall, the collation of the literature in wastewater treatment and agriculture serves to frame and identify potential concerns with respect to antibiotics, antibiotic resistant bacteria, and antibiotic resistance genes in reclaimed water.

Report on 1981 research result on the R and D of environmental resistance reinforcing element; 1981 nendo taikankyo kyoka soshi no kenkyuu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1982-03-01

This research was intended to establish technology for the substrate of an environmental resistance reinforcing element in which environmental resistance was enhanced against radiation, heat, mechanical shock, etc., for the purpose of realizing various kinds of equipment and devices for performing advanced information processing under severe environmental conditions of outer space, nuclear reactors, travelling objects such as automobiles and aircrafts, and plants. A grasp of the present point at issue and the examination of improving methods were conducted primarily on a ceramic package, for the purpose of R and D of the technology of a MOS type silicon integrated circuit element; further, in the evaluation test technology, the problems of the status quo were grasped through the understanding of the data of the existing elements. In the technology for a bipolar type silicon integrated circuit element. change in the properties by irradiation of radioactive rays was grasped on oxidized silicon and silicon substrate crystals as the technology for the element. In the R and D of the technology for a compound semiconductor integrated circuit element, the point at issue of the present technology grasped, with the improving method examined, primarily on the tri-plate structure of ceramics. (NEDO)

Reusing Treated Wastewater: Consideration of the Safety Aspects Associated with Antibiotic-Resistant Bacteria and Antibiotic Resistance Genes

KAUST Repository

Hong, Pei-Ying; Julian, Timothy; Pype, Marie-Laure; Jiang, Sunny; Nelson, Kara; Graham, David; Pruden, Amy; Manaia, Cé lia

2018-01-01

As more countries engage in water reuse, either intended or de facto, there is an urgent need to more comprehensively evaluate resulting environmental and public health concerns. While antibiotic-resistant bacteria (ARB) and antibiotic resistance

Environmental resistance and mechanical performance of basalt and glass fibers

International Nuclear Information System (INIS)

Wei Bin; Cao Hailin; Song Shenhua

2010-01-01

The treated basalt and glass fibers with sodium hydroxide and hydrochloric acid solutions for different times were analyzed, respectively. This paper summarized the mass loss ratio and the strength maintenance ratios of the fibers after treatment. The fibers' surface corrosion morphologies were characterized using scanning electron microscopy and their compositions were detected using energy dispersive X-ray spectroscopy. The acid resistance was much better than the alkali resistance for the basalt fibers. Nevertheless, for the glass fibers the situation is different: the acid resistance was almost the same as the alkali resistance. Among the two types of aqueous environments evaluated, the alkali solution is the most aggressive to the fibers' surface. The possible corrosion mechanisms are revealed.

An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats.

Directory of Open Access Journals (Sweden)

Jan B W J Cornelissen

Full Text Available High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment. Previous studies have indicated that bradyzoites are highly infectious for cats. To infect cats, tissue cysts were isolated from the brains of mice infected with oocysts of T. gondii M4 strain, and bradyzoites were released by pepsin digestion. Free bradyzoites were counted and graded doses (1000, 100, 50, 10, and 250 intact tissue cysts were inoculated orally into three cats each. Oocysts shed by these five groups of cats were collected from faeces by flotation techniques, counted microscopically and estimated by real time PCR. Additionally, the number of T. gondii in heart, tongue and brains were estimated, and serology for anti T. gondii antibodies was performed. A Beta-Poisson dose-response model was used to estimate the infectivity of single bradyzoites and linear regression was used to determine the relation between inoculated dose and numbers of oocyst shed. We found that real time PCR was more sensitive than microscopic detection of oocysts, and oocysts were detected by PCR in faeces of cats fed 10 bradyzoites but by microscopic examination. Real time PCR may only detect fragments of T. gondii DNA without the presence of oocysts in low doses. Prevalence of tissue cysts of T. gondii in tongue, heart and brains, and anti T. gondii antibody concentrations were all found to depend on the inoculated bradyzoite dose. The combination of the experimental challenge model and the dose response analysis provides a suitable reference for quantifying the potential reduction in human health risk due to a treatment of domestic cats by vaccination or by therapeutic drug application.

Environmental effects on electrical properties of Cr-Si-Ni resistive films deposited by magnetron sputtering

International Nuclear Information System (INIS)

Zhang Yuqin; Dong Xianping; Wu Jiansheng

2005-01-01

The present paper investigated the environmental effects on electrical properties stability and long-term reliability of magnetron sputtered Cr-Si-Ni resistive films in 3.5% NaCl, 0.5 M Na 2 SO 4 and 0.5 M HCl solutions at 25 deg. C, which simulated marine, industrial and acidic environments. The relative resistance change (ΔR/R) for the annealed films revealed that the films had the best electrical properties stability and long-term reliability in industrial environments at 25 deg. C. After immersion in corrosion solutions for 480 h, the value of ΔR/R for the films was only 0.41% in industrial environments, and the values were 0.56 and 1.96% in marine and acidic environments, respectively. The polarization measurements and AES results indicated that the films presented a spontaneous trend to passivation, and could form a dense and stable protective oxide layer (Si oxide) on its surface rapidly that protected the films from further corrosion in three different environments. Furthermore, the formed passive film in industrial environments exhibited much more protective effects on the films than in marine and acidic environments

Human, animal and environmental contributors to antibiotic resistance in low-resource settings: integrating behavioural, epidemiological and One Health approaches.

Science.gov (United States)

Rousham, Emily K; Unicomb, Leanne; Islam, Mohammad Aminul

2018-04-11

Antibiotic resistance (ABR) is recognized as a One Health challenge because of the rapid emergence and dissemination of resistant bacteria and genes among humans, animals and the environment on a global scale. However, there is a paucity of research assessing ABR contemporaneously in humans, animals and the environment in low-resource settings. This critical review seeks to identify the extent of One Health research on ABR in low- and middle-income countries (LMICs). Existing research has highlighted hotspots for environmental contamination; food-animal production systems that are likely to harbour reservoirs or promote transmission of ABR as well as high and increasing human rates of colonization with ABR commensal bacteria such as Escherichia coli However, very few studies have integrated all three components of the One Health spectrum to understand the dynamics of transmission and the prevalence of community-acquired resistance in humans and animals. Microbiological, epidemiological and social science research is needed at community and population levels across the One Health spectrum in order to fill the large gaps in knowledge of ABR in low-resource settings. © 2018 The Author(s).

Elevated Rate of Genome Rearrangements in Radiation-Resistant Bacteria.

Science.gov (United States)

Repar, Jelena; Supek, Fran; Klanjscek, Tin; Warnecke, Tobias; Zahradka, Ksenija; Zahradka, Davor

2017-04-01

A number of bacterial, archaeal, and eukaryotic species are known for their resistance to ionizing radiation. One of the challenges these species face is a potent environmental source of DNA double-strand breaks, potential drivers of genome structure evolution. Efficient and accurate DNA double-strand break repair systems have been demonstrated in several unrelated radiation-resistant species and are putative adaptations to the DNA damaging environment. Such adaptations are expected to compensate for the genome-destabilizing effect of environmental DNA damage and may be expected to result in a more conserved gene order in radiation-resistant species. However, here we show that rates of genome rearrangements, measured as loss of gene order conservation with time, are higher in radiation-resistant species in multiple, phylogenetically independent groups of bacteria. Comparison of indicators of selection for genome organization between radiation-resistant and phylogenetically matched, nonresistant species argues against tolerance to disruption of genome structure as a strategy for radiation resistance. Interestingly, an important mechanism affecting genome rearrangements in prokaryotes, the symmetrical inversions around the origin of DNA replication, shapes genome structure of both radiation-resistant and nonresistant species. In conclusion, the opposing effects of environmental DNA damage and DNA repair result in elevated rates of genome rearrangements in radiation-resistant bacteria. Copyright © 2017 Repar et al.

Calcium-Magnesium-Alumino-Silicates (CMAS) Reaction Mechanisms and Resistance of Advanced Turbine Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming; Costa, Gustavo; Harder, Bryan J.; Wiesner, Valerie L.; Hurst, Janet B.; Puleo, Bernadette J.

2017-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is an essential requirement to enable the applications of the 2700-3000 F EBC - CMC systems. This presentation primarily focuses on the reaction mechanisms of advanced NASA environmental barrier coating systems, when in contact with Calcium-Magnesium Alumino-Silicates (CMAS) at high temperatures. Advanced oxide-silicate defect cluster environmental barrier coatings are being designed for ultimate balanced controls of the EBC temperature capability and CMAS reactivity, thus improving the CMAS resistance. Further CMAS mitigation strategies are also discussed.

Environmentalism(s and natural assets: challenges to extractivism in Argentina and Brazil

Directory of Open Access Journals (Sweden)

Lucrecia Wagner

2013-11-01

Full Text Available This paper tackles environmental conflicts generated for struggles for land and water, facing the advance of the extractive frontier -principally, monocultures and mega mining- from the action of social movements in Brazil and Argentina.Considering the currents of environmentalism which get into a dispute over the appropriation of natural commons, we will argue how social movements in Brazil and Argentina demonstrate the fallacy of the hegemonic capitalist discourse about the environmental crisis. Thus, we will consider emblematic movements in each country: the Movement of “Trabajadores Rurales Sin Tierra (MST” of Brazil and the movements that resist the large-scale mining -or mega-mining-in Argentina. The characterization of these movements is grounded in researches that included interviews and field work in these territories of resistance.We believe that these conflicts and their social actors bring to light the inequalities inherent to the distribution of environmental impacts, which the rhetoric of sustainable development attempts to hide with its socially inclusive and environmentally friendly conception.Environmental conflicts provide the possibility of quashing the hegemonic image of an environmental crisis common to all and simultaneously, installing the discussion about the legitimate need of the appropriation of natural commons.

The antibiotic resistance "mobilome": searching for the link between environment and clinic.

Science.gov (United States)

Perry, Julie A; Wright, Gerard D

2013-01-01

Antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. The environmental "resistome" is the collection of all genes that directly or indirectly contribute to antibiotic resistance. Many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity), while others become resistance determinants only when mobilized and over-expressed in non-native hosts (like plasmid-encoded β-lactamases). The modern environmental resistome is under selective pressure from human activities such as agriculture, which may influence the composition of the local resistome and lead to gene transfer events. Beyond the environment, we are challenged in the clinic by the rise in both frequency and diversity of antibiotic resistant pathogens. We assume that clinical resistance originated in the environment, but few examples of direct gene exchange between the environmental resistome and the clinical resistome have been documented. Strong evidence exists to suggest that clinical aminoglycoside and vancomycin resistance enzymes, the extended-spectrum β-lactamase CTX-M and the quinolone resistance gene qnr have direct links to the environmental resistome. In this review, we highlight recent advances in our understanding of horizontal gene transfer of antibiotic resistance genes from the environment to the clinic. Improvements in sequencing technologies coupled with functional metagenomic studies have revealed previously underappreciated diversity in the environmental resistome, and also established novel genetic links to the clinic. Understanding mechanisms of gene exchange becomes vital in controlling the future dissemination of antibiotic resistance.

Antibiotic Resistance in Animal and Environmental Samples Associated with Small-Scale Poultry Farming in Northwestern Ecuador.

Science.gov (United States)

Braykov, Nikolay P; Eisenberg, Joseph N S; Grossman, Marissa; Zhang, Lixin; Vasco, Karla; Cevallos, William; Muñoz, Diana; Acevedo, Andrés; Moser, Kara A; Marrs, Carl F; Foxman, Betsy; Trostle, James; Trueba, Gabriel; Levy, Karen

2016-01-01

The effects of animal agriculture on the spread of antibiotic resistance (AR) are cross-cutting and thus require a multidisciplinary perspective. Here we use ecological, epidemiological, and ethnographic methods to examine populations of Escherichia coli circulating in the production poultry farming environment versus the domestic environment in rural Ecuador, where small-scale poultry production employing nontherapeutic antibiotics is increasingly common. We sampled 262 "production birds" (commercially raised broiler chickens and laying hens) and 455 "household birds" (raised for domestic use) and household and coop environmental samples from 17 villages between 2010 and 2013. We analyzed data on zones of inhibition from Kirby-Bauer tests, rather than established clinical breakpoints for AR, to distinguish between populations of organisms. We saw significantly higher levels of AR in bacteria from production versus household birds; resistance to either amoxicillin-clavulanate, cephalothin, cefotaxime, and gentamicin was found in 52.8% of production bird isolates and 16% of household ones. A strain jointly resistant to the 4 drugs was exclusive to a subset of isolates from production birds (7.6%) and coop surfaces (6.5%) and was associated with a particular purchase site. The prevalence of AR in production birds declined with bird age (P resistance (AR) in E. coli isolates from small-scale poultry production environments versus domestic environments in rural Ecuador, where such backyard poultry operations have become established over the past decade. Our previous research in the region suggests that introduction of AR bacteria through travel and commerce may be an important source of AR in villages of this region. This report extends the prior analysis by examining small-scale production chicken farming as a potential source of resistant strains. Our results suggest that AR strains associated with poultry production likely originate from sources outside the study

Improved annotation of antibiotic resistance determinants reveals microbial resistomes cluster by ecology

OpenAIRE

Gibson, Molly K; Forsberg, Kevin J; Dantas, Gautam

2014-01-01

Antibiotic resistance is a dire clinical problem with important ecological dimensions. While antibiotic resistance in human pathogens continues to rise at alarming rates, the impact of environmental resistance on human health is still unclear. To investigate the relationship between human-associated and environmental resistomes, we analyzed functional metagenomic selections for resistance against 18 clinically relevant antibiotics from soil and human gut microbiota as well as a set of multidr...

Effects of environmental factors and management practices on microclimate, winter physiology, and frost resistance in trees.

Science.gov (United States)

Charrier, Guillaume; Ngao, Jérôme; Saudreau, Marc; Améglio, Thierry

2015-01-01

Freezing stress is one of the most important limiting factors determining the ecological distribution and production of tree species. Assessment of frost risk is, therefore, critical for forestry, fruit production, and horticulture. Frost risk is substantial when hazard (i.e., exposure to damaging freezing temperatures) intersects with vulnerability (i.e., frost sensitivity). Based on a large number of studies on frost resistance and frost occurrence, we highlight the complex interactive roles of environmental conditions, carbohydrates, and water status in frost risk development. To supersede the classical empirical relations used to model frost hardiness, we propose an integrated ecophysiologically-based framework of frost risk assessment. This framework details the individual or interactive roles of these factors, and how they are distributed in time and space at the individual-tree level (within-crown and across organs). Based on this general framework, we are able to highlight factors by which different environmental conditions (e.g., temperature, light, flood, and drought), and management practices (pruning, thinning, girdling, sheltering, water aspersion, irrigation, and fertilization) influence frost sensitivity and frost exposure of trees.

Comparison between McMaster and Mini-FLOTAC methods for the enumeration of Eimeria maxima oocysts in poultry excreta.

Science.gov (United States)

Bortoluzzi, C; Paras, K L; Applegate, T J; Verocai, G G

2018-04-30

Monitoring Eimeria shedding has become more important due to the recent restrictions to the use of antibiotics within the poultry industry. Therefore, there is a need for the implementation of more precise and accurate quantitative diagnostic techniques. The objective of this study was to compare the precision and accuracy between the Mini-FLOTAC and the McMaster techniques for quantitative diagnosis of Eimeria maxima oocyst in poultry. Twelve pools of excreta samples of broiler chickens experimentally infected with E. maxima were analyzed for the comparison between Mini-FLOTAC and McMaster technique using, the detection limits (dl) of 23 and 25, respectively. Additionally, six excreta samples were used to compare the precision of different dl (5, 10, 23, and 46) using the Mini-FLOTAC technique. For precision comparisons, five technical replicates of each sample (five replicate slides on one excreta slurry) were read for calculating the mean oocyst per gram of excreta (OPG) count, standard deviation (SD), coefficient of variation (CV), and precision of both aforementioned comparisons. To compare accuracy between the methods (McMaster, and Mini-FLOTAC dl 5 and 23), excreta from uninfected chickens was spiked with 100, 500, 1,000, 5,000, or 10,000 OPG; additional samples remained unspiked (negative control). For each spiking level, three samples were read in triplicate, totaling nine reads per spiking level per technique. Data were transformed using log10 to obtain normality and homogeneity of variances. A significant correlation (R = 0.74; p = 0.006) was observed between the mean OPG of the McMaster dl 25 and the Mini-FLOTAC dl 23. Mean OPG, CV, SD, and precision were not statistically different between the McMaster dl 25 and Mini-FLOTAC dl 23. Despite the absence of statistical difference (p > 0.05), Mini-FLOTAC dl 5 showed a numerically lower SD and CV than Mini-FLOTAC dl 23. The Pearson correlation coefficient revealed significant and positive

A Novel Environmental Azole Resistance Mutation in Aspergillus fumigatus and a Possible Role of Sexual Reproduction in Its Emergence

Directory of Open Access Journals (Sweden)

Jianhua Zhang

2017-06-01

Full Text Available This study investigated the dynamics of Aspergillus fumigatus azole-resistant phenotypes in two compost heaps with contrasting azole exposures: azole free and azole exposed. After heat shock, to which sexual but not asexual spores are highly resistant, the azole-free compost yielded 98% (49/50 wild-type and 2% (1/50 azole-resistant isolates, whereas the azole-containing compost yielded 9% (4/45 wild-type and 91% (41/45 resistant isolates. From the latter compost, 80% (36/45 of the isolates contained the TR46/Y121F/T289A genotype, 2% (1/45 harbored the TR46/Y121F/M172I/T289A/G448S genotype, and 9% (4/45 had a novel pan-triazole-resistant mutation (TR463/Y121F/M172I/T289A/G448S with a triple 46-bp promoter repeat. Subsequent screening of a representative set of clinical A. fumigatus isolates showed that the novel TR463 mutant was already present in samples from three Dutch medical centers collected since 2012. Furthermore, a second new resistance mutation was found in this set that harbored four TR46 repeats. Importantly, in the laboratory, we recovered the TR463 mutation from a sexual cross between two TR46 isolates from the same azole-containing compost, possibly through unequal crossing over between the double tandem repeats (TRs during meiosis. This possible role of sexual reproduction in the emergence of the mutation was further implicated by the high level of genetic diversity of STR genotypes in the azole-containing compost. Our study confirms that azole resistance mutations continue to emerge in the environment and indicates compost containing azole residues as a possible hot spot. Better insight into the biology of environmental resistance selection is needed to retain the azole class for use in food production and treatment of Aspergillus diseases.

Novel resistance functions uncovered using functional metagenomic investigations of resistance reservoirs

Directory of Open Access Journals (Sweden)

Erica C. Pehrsson

2013-06-01

Full Text Available Rates of infection with antibiotic-resistant bacteria have increased precipitously over the past several decades, with far-reaching healthcare and societal costs. Recent evidence has established a link between antibiotic resistance genes in human pathogens and those found in non-pathogenic, commensal, and environmental organisms, prompting deeper investigation of natural and human-associated reservoirs of antibiotic resistance. Functional metagenomic selections, in which shotgun-cloned DNA fragments are selected for their ability to confer survival to an indicator host, have been increasingly applied to the characterization of many antibiotic resistance reservoirs. These experiments have demonstrated that antibiotic resistance genes are highly diverse and widely distributed, many times bearing little to no similarity to known sequences. Through unbiased selections for survival to antibiotic exposure, functional metagenomics can improve annotations by reducing the discovery of false-positive resistance and by allowing for the identification of previously unrecognizable resistance genes. In this review, we summarize the novel resistance functions uncovered using functional metagenomic investigations of natural and human-impacted resistance reservoirs. Examples of novel antibiotic resistance genes include those highly divergent from known sequences, those for which sequence is entirely unable to predict resistance function, bifunctional resistance genes, and those with unconventional, atypical resistance mechanisms. Overcoming antibiotic resistance in the clinic will require a better understanding of existing resistance reservoirs and the dissemination networks that govern horizontal gene exchange, informing best practices to limit the spread of resistance-conferring genes to human pathogens.

[State-of-the-art status on airborne antibiotic resistant bacteria and antibiotic resistance genes].

Science.gov (United States)

Li, J; Yao, M S

2018-04-06

The world is facing more deaths due to increasing antibiotic-resistant bacterial infections and the shortage of new highly effective antibiotics, however the air media as its important transmission route has not been adequately studied. Based on the latest literature acquired in this work, we have discussed the state-of-the-art research progress of the concentration, distribution and spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in different environmental air media, and also analyzed some future prevention and control measures. The large use of antibiotics in the medical settings and animal husbandry places has resulted in higher abundances of ARB and ARGs in the relevant and surrounding atmosphere than in urban and general indoor air environments. ARGs can be spread by adhering to airborne particles, and researchers have also found that air media contain more abundant ARGs than other environmental media such as soil, water and sediment. It was suggested in this review that strengthening the monitoring, study on spreading factors and biological toxicity, and also research and development on pathogen accurate diagnosis and new green antibiotic are expected to help effectively monitor, prevent and control of the impacts of airborne resistant bacteria and resistance genes on both human and ecologies.

FARME DB: a functional antibiotic resistance element database

OpenAIRE

Wallace, James C.; Port, Jesse A.; Smith, Marissa N.; Faustman, Elaine M.

2017-01-01

Antibiotic resistance (AR) is a major global public health threat but few resources exist that catalog AR genes outside of a clinical context. Current AR sequence databases are assembled almost exclusively from genomic sequences derived from clinical bacterial isolates and thus do not include many microbial sequences derived from environmental samples that confer resistance in functional metagenomic studies. These environmental metagenomic sequences often show little or no similarity to AR se...

Market applications of Resistivity, Induced Polarisation, Magnetic Resonance and Electromagnetic methods for Groundwater Investigations, Mining Exploration, Environmental and Engineering Surveys

Science.gov (United States)

Bernard, J.

2012-12-01

The Manufacturers of geophysical instruments have been facing these past decades the fast evolution of the electronics and of the computer sciences. More automatisms have been introduced into the equipment and into the processing and interpretation software which may let believe that conducting geophysical surveys requires less understanding of the method and less experience than in the past. Hence some misunderstandings in the skills that are needed to make the geophysical results well integrated among the global information which the applied geologist needs to acquire to be successful in his applications. Globally, the demand in geophysical investigation goes towards more penetration depth, requiring more powerful transmitters, and towards a better resolution, requiring more data such as in 3D analysis. Budgets aspects strongly suggest a high efficiency in the field associated to high speed data processing. The innovation is required in all aspects of geophysics to fit with the market needs, including new technological (instruments, software) and methodological (methods, procedures, arrays) developments. The structures in charge of the geophysical work can be public organisations (institutes, ministries, geological surveys,…) or can come from the private sector (large companies, sub-contractors, consultants, …), each one of them getting their own constraints in the field work and in the processing and interpretation phases. In the applications concerning Groundwater investigations, Mining Exploration, Environmental and Engineering surveys, examples of data and their interpretation presently carried out all around the world will be presented for DC Resistivity (Vertical Electrical Sounding, 2D, 3D Resistivity Imaging, Resistivity Monitoring), Induced Polarisation (Time Domain 2D, 3D arrays for mining and environmental), Magnetic Resonance Sounding (direct detection and characterisation of groundwater) and Electromagnetic (multi-component and multi

Role of infection control in combating antibiotic resistance

African Journals Online (AJOL)

of multidrug-resistant organisms (MDROs) in healthcare settings and interventions to prevent infection. Transmission of multidrug-resistant ... healthcare workers (HCWs) or visitors), although transmission from environmental sources has also ...

The Antibiotic Resistance ‘Mobilome’: searching for the link between environment and clinic.

Directory of Open Access Journals (Sweden)

Julie ePerry

2013-05-01

Full Text Available Antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. The environmental ‘resistome’ is the collection of all genes that directly or indirectly contribute to antibiotic resistance. Many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity, while others become resistance determinants only when mobilized and over-expressed in non-native hosts (like plasmid-based β-lactamases. The modern environmental resistome is under selective pressure from human activities such as agriculture, which may influence the composition of the local resistome and lead to gene transfer events. Beyond the environment, we are challenged in the clinic by the rise in both frequency and diversity of antibiotic resistant pathogens. We assume that clinical resistance originated in the environment, but few examples of direct gene exchange between the environmental resistome and the clinical resistome have been documented. Strong evidence exists to suggest that clinical aminoglycoside and vancomycin resistance enzymes, the extended-spectrum β-lactamase CTX-M and the quinolone resistance gene Qnr have direct links to the environmental resistome. In this review, we highlight recent advances in our understanding of horizontal gene transfer of antibiotic resistance genes from the environment to the clinic. Improvements in sequencing technologies coupled with functional metagenomic studies have revealed previously underappreciated diversity in the environmental resistome, and also established novel genetic links to the clinic. Understanding mechanisms of gene exchange becomes vital in controlling the future dissemination of antibiotic resistance.

The antibiotic resistance “mobilome”: searching for the link between environment and clinic

Science.gov (United States)

Perry, Julie A.; Wright, Gerard D.

2013-01-01

Antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. The environmental “resistome” is the collection of all genes that directly or indirectly contribute to antibiotic resistance. Many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity), while others become resistance determinants only when mobilized and over-expressed in non-native hosts (like plasmid-encoded β-lactamases). The modern environmental resistome is under selective pressure from human activities such as agriculture, which may influence the composition of the local resistome and lead to gene transfer events. Beyond the environment, we are challenged in the clinic by the rise in both frequency and diversity of antibiotic resistant pathogens. We assume that clinical resistance originated in the environment, but few examples of direct gene exchange between the environmental resistome and the clinical resistome have been documented. Strong evidence exists to suggest that clinical aminoglycoside and vancomycin resistance enzymes, the extended-spectrum β-lactamase CTX-M and the quinolone resistance gene qnr have direct links to the environmental resistome. In this review, we highlight recent advances in our understanding of horizontal gene transfer of antibiotic resistance genes from the environment to the clinic. Improvements in sequencing technologies coupled with functional metagenomic studies have revealed previously underappreciated diversity in the environmental resistome, and also established novel genetic links to the clinic. Understanding mechanisms of gene exchange becomes vital in controlling the future dissemination of antibiotic resistance. PMID:23755047

extensive and semi-intensive management systems in northern ghana

African Journals Online (AJOL)

management systems was positive and linearly correlated with eggs/oocysts of all the three intestinal parasites and became ... respectively was also positive but not significant under the semi-intensive system of management. Younger animals in the extensive ..... ruminants in Malaysia: Resistance to anthelmintics and the ...

Compound deterioration properties of non-halogen flame-resisting cables

International Nuclear Information System (INIS)

Yamamoto, Yasuaki; Yagyu, Hideki; Onishi, Takao; Kamiharako, Shinji

1984-01-01

Conventional flame-resisting cables release harmful gas such as hydrogen chloride and smoke on burning. To improve this disadvantage, the cables for nuclear power plants using new non-halogen flame-resisting insulating material have been developed. In this experiment, the non-halogen flame-resisting cables were subjected to the environmental test with varying test conditions. The test conditions included the order of exposure (heat treatment, γ-ray irradiation and steam exposure) and dose rate. After the environmental test, the mechanical and electrical properties of the samples were measured. In all test conditions, the samples did not crack in bending, and withstood the bending and withstand-voltage in-water test. The tensile strength and a.c. breakdown voltage did not change, and were stable. The elongation decreased greatly, but maintained the value of about 100 %, and the volumetric resistivity decreased by only one figure. It was confirmed that these cables were able to withstand various environmental tests. (Yoshitake, I.)

Sulfonamide-Resistant Bacteria and Their Resistance Genes in Soils Fertilized with Manures from Jiangsu Province, Southeastern China

OpenAIRE

Wang, Na; Yang, Xiaohong; Jiao, Shaojun; Zhang, Jun; Ye, Boping; Gao, Shixiang

2014-01-01

Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of a...

Azole-Resistant Invasive Aspergillosis

DEFF Research Database (Denmark)

Stensvold, Christen Rune; Jørgensen, Lise Nistrup; Arendrup, Maiken Cavling

2012-01-01

with point mutation (s) in CYP51A (TR34/L98H and TR46/Y121F/T289A). In the third a single target enzyme alteration (G432S) is found. These resistant “environmental” strains have been detected in many West-European countries as well as in the Asia- Pacifics. Noticeably, these two continents account...... and classes available is impressive compared to the armamentarium in human medicine, azoles will remain the most important group in agriculture due to superior field performance and significant resistance in fungal pathogens to other compounds. Hence, further spread of environmental resistant Aspergillus...

Resistance of Bacillus Endospores to Extreme Terrestrial and Extraterrestrial Environments

Science.gov (United States)

Nicholson, Wayne L.; Munakata, Nobuo; Horneck, Gerda; Melosh, Henry J.; Setlow, Peter

2000-01-01

Endospores of Bacillus spp., especially Bacillus subtilis, have served as experimental models for exploring the molecular mechanisms underlying the incredible longevity of spores and their resistance to environmental insults. In this review we summarize the molecular laboratory model of spore resistance mechanisms and attempt to use the model as a basis for exploration of the resistance of spores to environmental extremes both on Earth and during postulated interplanetary transfer through space as a result of natural impact processes. PMID:10974126

Radiation resistance of cable insulation and jacket materials for nuclear power plants

International Nuclear Information System (INIS)

Morita, Minoru; Kon, Shuji; Nishikawa, Ichiro

1978-01-01

The cables for use in nuclear power plants are required to satisfy the specific environmental resistance and excellent flame resistance as stipulated in IEEE Std. 383. The materials to be used to cables intended for this specific purpose of use must therefore be strictly tested so as to evaluate their flame resistance in addition to compliance with various environmental requirements, such as heat resistance, water-vapor resistance, and radiation resistance. This paper describes general information on radiation resistance and deterioration of various high-molecular materials, suggests the direction of efforts to be made to improve their properties including flame resistance of various rubber and plastic materials for cables to be used in nuclear power plants, and indicates the performance characteristics of such materials. (author)

Occurrence of Giardia cysts and Cryptosporidium oocysts in activated sludge samples in Campinas, SP, Brazil.

Science.gov (United States)

Santos, Luciana Urbano; Bonatti, Taís Rondello; Cantusio Neto, Romeu; Franco, Regina Maura Bueno

2004-01-01

Giardia and Cryptosporidium have caused several outbreaks of gastroenteritis in humans associated with drinking water. Contaminated sewage effluents are recognized as a potential source of waterborne protozoa. Due to the lack of studies about the occurrence of these parasites in sewage samples in Brazil, we compared the efficiency of two procedures for concentrating cysts and oocysts in activated sludge samples of one sewage treatment plant. For this, the samples were submitted to i) concentration by the ether clarification procedure (ECP) and to ii) purification by sucrose flotation method (SFM) and aliquots of the pellets were examined by immunofluorescence. Giardia cysts were present in all samples (100.0%; n = 8) when using ECP and kit 1 reagents, while kit 2 resulted in six positive samples (85.7%; n = 7). As for SFM, cysts were detected in 75.0% and 100.0% of these samples (for kit 1 and 2, respectively). Regarding Cryptosporidium, two samples (25.0%; kit 1 and 28.5% for kit 2) were detected positive by using ECP, while for SFM, only one sample (examined by kit 1) was positive (12.5%). The results of the control trial revealed Giardia and Cryptosporidium recovery efficiency rates for ECP of 54.5% and 9.6%, while SFM was 10.5% and 3.2%, respectively. Considering the high concentration detected, a previous evaluation of the activated sludge before its application in agriculture is recommended and with some improvement, ECP would be an appropriate simple technique for protozoa detection in sewage samples.

Search Engine for Antimicrobial Resistance: A Cloud Compatible Pipeline and Web Interface for Rapidly Detecting Antimicrobial Resistance Genes Directly from Sequence Data.

Science.gov (United States)

Rowe, Will; Baker, Kate S; Verner-Jeffreys, David; Baker-Austin, Craig; Ryan, Jim J; Maskell, Duncan; Pearce, Gareth

2015-01-01

Antimicrobial resistance remains a growing and significant concern in human and veterinary medicine. Current laboratory methods for the detection and surveillance of antimicrobial resistant bacteria are limited in their effectiveness and scope. With the rapidly developing field of whole genome sequencing beginning to be utilised in clinical practice, the ability to interrogate sequencing data quickly and easily for the presence of antimicrobial resistance genes will become increasingly important and useful for informing clinical decisions. Additionally, use of such tools will provide insight into the dynamics of antimicrobial resistance genes in metagenomic samples such as those used in environmental monitoring. Here we present the Search Engine for Antimicrobial Resistance (SEAR), a pipeline and web interface for detection of horizontally acquired antimicrobial resistance genes in raw sequencing data. The pipeline provides gene information, abundance estimation and the reconstructed sequence of antimicrobial resistance genes; it also provides web links to additional information on each gene. The pipeline utilises clustering and read mapping to annotate full-length genes relative to a user-defined database. It also uses local alignment of annotated genes to a range of online databases to provide additional information. We demonstrate SEAR's application in the detection and abundance estimation of antimicrobial resistance genes in two novel environmental metagenomes, 32 human faecal microbiome datasets and 126 clinical isolates of Shigella sonnei. We have developed a pipeline that contributes to the improved capacity for antimicrobial resistance detection afforded by next generation sequencing technologies, allowing for rapid detection of antimicrobial resistance genes directly from sequencing data. SEAR uses raw sequencing data via an intuitive interface so can be run rapidly without requiring advanced bioinformatic skills or resources. Finally, we show that SEAR

Phenotypic and genotypic anti-microbial resistance profiles of campylobacters from untreated feedlot cattle and their environment.

Science.gov (United States)

Minihan, D; Whyte, P; O'mahony, M; Cowley, D; O'halloran, F; Corcoran, D; Fanning, S; Collins, J D

2006-05-01

Anti-microbial resistance is an emerging public health issue. Farmed animals may act as reservoirs and potential sources of anti-microbial resistant Campylobacters. The aim of this study was to investigate the anti-microbial resistance profile of cattle and environmental Campylobacter isolates from normal untreated feedlot cattle, the role of the gyrA Thr-86-Ile mutation in ciprofloxacin-resistant Campylobacter jejuni isolates and the involvement of the tripartite CmeABC efflux system for multi-resistant C. jejuni isolates. The phenotypic anti-microbial resistance testing was carried out on 500 Campylobacter isolates (445 cattle isolates and 55 environmental isolates). In general, there was a higher level of anti-microbial resistance for the environmental isolates compared with the animal isolates, 45% of the animal isolates were resistant to one or more of the seven anti-microbials compared with 84% of the environmental isolates. The combined cattle and environmental Campylobacters had 34 (6.8%) isolates resistant to three or more of the seven anti-microbials tested on all isolates and 11 (2.2%) isolates were resistant to the seven anti-microbials. There was a substantial level of ciprofloxacin-resistant Campylobacters in both animal (8.5%) and environmental (21.8%) isolates. The gyrA Thr-86-Ile mutation was only present in five of 22 ciprofloxacin-resistant C. jejuni isolates investigated. No multi-drug-resistant associated mutation was detected in the CmeB or the CmeR regions investigated. In conclusion, our study observed a substantial level of Campylobacter anti-microbial resistance, highlighting the need for an active anti-microbial surveillance program for food animals in Ireland and the importance of the chosen sampling point can have on the findings of such a program.

Isolation and characterization of viable Toxoplasma gondii isolates revealed possible high frequency of mixed infection in feral cats ( Felis domesticus) from St Kitts, West Indies.

Science.gov (United States)

Dubey, J P; Moura, L; Majumdar, D; Sundar, N; Velmurugan, G V; Kwok, O C H; Kelly, P; Krecek, R C; Su, C

2009-05-01

Cats are essential in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete the environmentally resistant oocysts in nature. Samples of serum, feces, and tissues from feral cats from St Kitts, West Indies were examined for T. gondii infection. Antibodies to T. gondii were assayed by the modified agglutination test, and found in 71 of 96 (73.9%) of cats with titres of 1:10 in six, 1: 20 in six,1:40 in seven,1: 80 in three, 1: 160 in 10, 1:320 in 13, 1:640 in nine, and 1:1,280 or higher in 17. Tissues of 10 cats were bio-assayed in mice. Toxoplasma gondii was isolated from tissues of 7 cats; from hearts of 6, from tongue of 5, and brains of 3 cats. All 7 isolates were avirulent for mice. Toxoplasma gondii oocysts were not found in the feces of 51 cats. Genotyping of these 7 T. gondii isolates by 10 multi-locus PCR-RFLP markers, including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and an apicoplast marker, Apico, revealed 4 genotypes, including clonal Type II, Type III and 2 unique genotypes. Five of the 7 cats had infection with 2 genotypes, indicating high frequency of mixed infection in the cat population on the St Kitts island.

Uranium interaction with two multi-resistant environmental bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris.

Science.gov (United States)

Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

2012-01-01

Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations.

Uranium Interaction with Two Multi-Resistant Environmental Bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris

Science.gov (United States)

Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

2012-01-01

Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations. PMID:23251623

[Assessment of eco-environmental vulnerability of Hainan Island, China].

Science.gov (United States)

Huang, Bao-rong; Ouyang, Zhi-yun; Zhang, Hui-zhi; Zhang, Li-hua; Zheng, Hua

2009-03-01

Based on the assessment method of environmental vulnerability constructed by SOPAC and UNEP, this paper constructed an indicator system from three sub-themes including hazard, resistance, and damage to assess the eco-environmental vulnerability of Hainan Island. The results showed that Hainan Island was suffering a middling level eco-environmental hazard, and the main hazards came from some intensive human activities such as intensive agriculture, mass tourism, mining, and a mass of solid wastes thrown by islanders and tourists. Some geographical characters such as larger land area, larger altitude range, integrated geographical form, and abundant habitat types endowed Hainan Island higher resistance to environmental hazards. However, disturbed by historical accumulative artificial and natural hazards, the Island ecosystem had showed serious ecological damage, such as soil degradation and biodiversity loss. Comprehensively considered hazard, resistance, damage, and degradation, the comprehensive environmental vulnerability of the Island was at a middling level. Some indicators showed lower vulnerability, but some showed higher vulnerability.

Isolation of Environmental Bacteria from Surface and Drinking Water in Mafikeng, South Africa, and Characterization Using Their Antibiotic Resistance Profiles

Directory of Open Access Journals (Sweden)

Suma George Mulamattathil

2014-01-01

Full Text Available The aim of this study was to isolate and identify environmental bacteria from various raw water sources as well as the drinking water distributions system in Mafikeng, South Africa, and to determine their antibiotic resistance profiles. Water samples from five different sites (raw and drinking water were analysed for the presence of faecal indicator bacteria as well as Aeromonas and Pseudomonas species. Faecal and total coliforms were detected in summer in the treated water samples from the Modimola dam and in the mixed water samples, with Pseudomonas spp. being the most prevalent organism. The most prevalent multiple antibiotic resistance phenotype observed was KF-AP-C-E-OT-K-TM-A. All organisms tested were resistant to erythromycin, trimethoprim, and amoxicillin. All isolates were susceptible to ciprofloxacin and faecal coliforms and Pseudomonas spp. to neomycin and streptomycin. Cluster analysis based on inhibition zone diameter data suggests that the isolates had similar chemical exposure histories. Isolates were identified using gyrB, toxA, ecfX, aerA, and hylH gene fragments and gyrB, ecfX, and hylH fragments were amplified. These results demonstrate that (i the drinking water from Mafikeng contains various bacterial species and at times faecal and total coliforms. (ii The various bacteria are resistant to various classes of antibiotics.

Health Impacts of Environmental Mycobacteria†

OpenAIRE

Primm, Todd P.; Lucero, Christie A.; Falkinham, Joseph O.

2004-01-01

Environmental mycobacteria are emerging pathogens causing opportunistic infections in humans and animals. The health impacts of human-mycobacterial interactions are complex and likely much broader than currently recognized. Environmental mycobacteria preferentially survive chlorination in municipal water, using it as a vector to infect humans. Widespread chlorination of water has likely selected more resistant environmental mycobacteria species and potentially explains the shift from M. scrof...

Improved concrete properties to resist the saline water using environmental by-product

Directory of Open Access Journals (Sweden)

Mohamed Anwar

2013-10-01

Full Text Available This paper investigates the influence of using environmental by-product materials (silica fume and fly ash in concrete on the chloride ion permeability of concrete. Nine concrete mixtures were designed to have the same degree of workability and air content with water/cementitious material ratio of 0.4. The studied parameters include the main fresh and hardened concrete properties such as slump, air content, unit weight, compressive strength, tensile strength, flexural strength, static Young's modulus, and dynamic elastic modulus. Concrete samples were kept in water for 28 days, then immersed in artificial sea water for 5 months. The total and soluble chloride contents were measured through the concrete using the potentiometric titration analysis. The obtained test results indicated that the use of ternary systems in concrete improved the different characteristics of the product concrete and showed a significant resistance to chloride penetration. The weights of chloride in mix 9 (10% silica fume and 25% fly ash at depths from the concrete surface to 30 mm were less than the weights of control mix 1 (100% ordinary Portland cement by about 60%. Further, the ternary systems can be used in concrete industry with considerable proportions.

Molecular mechanisms of methicillin resistance in Staphylococcus aureus.

Science.gov (United States)

Domínguez, M A; Liñares, J; Martín, R

1997-09-01

Methicillin-resistant Staphylococcus aureus (MRSA) strains are among the most common nosocomial pathogens. The most significant mechanism of resistance to methicillin in this-species is the acquisition of a genetic determinant (mecA gene). However, resistance seems to have a more complex molecular basis, since additional chromosomal material is involved in such resistance. Besides, overproduction of penicillinase and/or alterations in the PBPs can contribute to the formation of resistance phenotypes. Genetic and environmental factors leading to MRSA are reviewed.

Antimicrobial resistance in the environment

National Research Council Canada - National Science Library

Keen, Patricia L; Montforts, M. H. M. M

2012-01-01

... or antibiotic resistance genes as environmental contaminants. It also considers alternate uses and functions for antimicrobial compounds other than those intended for medicinal purposes in humans, animals, and fish...

Contamination of environmental surfaces by methicillin-resistant Staphylococcus aureus (MRSA) in rooms of inpatients with MRSA-positive body sites.

Science.gov (United States)

Kurashige, E Jessica Ohashi; Oie, Shigeharu; Furukawa, H

2016-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) can contaminate environmental surfaces that are frequently touched by the hands of patients with MRSA colonization/infection. There have been many studies in which the presence or absence of MRSA contamination was determined but no studies in which MRSA contamination levels were also evaluated in detail. We evaluated MRSA contamination of environmental surfaces (overbed tables, bed side rails, and curtains) in the rooms of inpatients from whom MRSA was isolated via clinical specimens. We examined the curtains within 7-14 days after they had been newly hung. The environmental surfaces were wiped using gauze (molded gauze for wiping of surface bacteria; 100% cotton, 4cm×8cm) moistened with sterile physiological saline. The MRSA contamination rate and mean counts (range) were 25.0% (6/24 samples) and 30.6 (0-255)colony-forming units (cfu)/100cm(2), respectively, for the overbed tables and 31.6% (6/19 samples) and 159.5 (0-1620)cfu/100cm(2), respectively, for the bed side rails. No MRSA was detected in 24 curtain samples. The rate of MRSA contamination of environmental surfaces was high for the overbed tables and bed side rails but low for the curtains. Therefore, at least until the 14th day of use, frequent disinfection of curtains may be not necessary. Copyright © 2016. Published by Elsevier Editora Ltda.

The Resistome: A Comprehensive Database of Escherichia coli Resistance Phenotypes.

Science.gov (United States)

Winkler, James D; Halweg-Edwards, Andrea L; Erickson, Keesha E; Choudhury, Alaksh; Pines, Gur; Gill, Ryan T

2016-12-16

The microbial ability to resist stressful environmental conditions and chemical inhibitors is of great industrial and medical interest. Much of the data related to mutation-based stress resistance, however, is scattered through the academic literature, making it difficult to apply systematic analyses to this wealth of information. To address this issue, we introduce the Resistome database: a literature-curated collection of Escherichia coli genotypes-phenotypes containing over 5,000 mutants that resist hundreds of compounds and environmental conditions. We use the Resistome to understand our current state of knowledge regarding resistance and to detect potential synergy or antagonism between resistance phenotypes. Our data set represents one of the most comprehensive collections of genomic data related to resistance currently available. Future development will focus on the construction of a combined genomic-transcriptomic-proteomic framework for understanding E. coli's resistance biology. The Resistome can be downloaded at https://bitbucket.org/jdwinkler/resistome_release/overview .

Context matters — the complex interplay between resistome genotypes and resistance phenotypes

DEFF Research Database (Denmark)

Dantas, Gautam; Sommer, Morten

2012-01-01

Application of metagenomic functional selections to study antibiotic resistance genes is revealing a highly diverse and complex network of genetic exchange between bacterial pathogens and environmental reservoirs, which likely contributes significantly to increasing resistance levels in pathogens...... the resistome genotype, and we highlight examples of genes and their hosts where this distinction becomes important in order to understand the relevance of environmental niches that contribute most to clinical problems associated with antibiotic resistance....

Research progress and application prospect of radiation-resistant prokaryotic microbe

International Nuclear Information System (INIS)

Wang Wei; Zhu Jing; Zhang Zhidong; Tang Qiyong; Chen Ming

2013-01-01

Radiation-resistant microbe is becoming the research hotspot because of its special life phenomenon and physiological mechanism. Radiation-resistant bacteria are one kind of the most studied radiation-resistant microbe. This article summarized some aspects of the research on radiation-resistant bacteria, including the radiation resistant bacteria resources, and discussed its potential application prospects in the environmental engineering, biotechnology, human health, military and space et al. (authors)

A Fully Transparent Resistive Memory for Harsh Environments

KAUST Repository

Yang, Po-Kang; Ho, Chih-Hsiang; Lien, Der-Hsien; Duran Retamal, Jose Ramon; Kang, Chen-Fang; Chen, Kuan-Ming; Huang, Teng-Han; Yu, Yueh-Chung; Wu, Chih-I; He, Jr-Hau

2015-01-01

A fully transparent resistive memory (TRRAM) based on Hafnium oxide (HfO2) with excellent transparency, resistive switching capability, and environmental stability is demonstrated. The retention time measured at 85 °C is over 3 × 104 sec

Detection of Toxoplasmosis in Environmental Samples at a Wet Market of a Capital City Centre

Directory of Open Access Journals (Sweden)

Amal R. Nimir

2011-01-01

Full Text Available The local Chow Kit market is the largest wet market in the city of Kuala Lumpur. It is very close to the biggest government hospital in the city centre. However, the level of cleanliness in this area is always questionable and a matter of concern. The aim of this study was to identify the prevalence of T. gondii oocyst in water samples used by hawkers in that market and tissue cysts in rats’ brains captured from the same area. Water samples were taken to the parasitology laboratory at the National Universtiy of MalaysiaUniversity and a sugar flotation concentration method was used. Supernatant microscopical examination was then performed. A total of 752 slides were screened for the presence of T. gondii oocyst. A hundred rats wandering in the same area were also captured by the hawkers using mousetraps. After each animal was sacrificed, and an electric microtome was used to cut out serial sections 5μ thick from the rat brains. The de-waxed tissue sections were stained by the progressive Haematoxylin and Eosin (H&E stain for microscopical examination. A total of 1000 slides were screened under a light microscope to detect the presence of T. gondii brain cysts. All the water samples were found to be negative for T. gondii oocyst. Out of the 100 rats captured, three rats were found to possess T. gondii cysts in their brains. Water samples reflect minimal or no solid food contamination, while the 3% of positive brain cysts influence the researchers to broaden their investigations for future projects.

Dietary Curcuma longa enhances resistance against Eimeria maxima and Eimeria tenella infections in chickens.

Science.gov (United States)

Kim, Duk Kyung; Lillehoj, Hyun S; Lee, Sung Hyen; Jang, Seung I; Lillehoj, Erik P; Bravo, David

2013-10-01

The effects of dietary supplementation with an organic extract of Curcuma longa on systemic and local immune responses to experimental Eimeria maxima and Eimeria tenella infections were evaluated in commercial broiler chickens. Dietary supplementation with C. longa enhanced coccidiosis resistance as demonstrated by increased BW gains, reduced fecal oocyst shedding, and decreased gut lesions compared with infected birds fed a nonsupplemented control diet. The chickens fed C. longa-supplemented diet showed enhanced systemic humoral immunity, as assessed by greater levels of serum antibodies to an Eimeria microneme protein, MIC2, and enhanced cellular immunity, as measured by concanavalin A-induced spleen cell proliferation, compared with controls. At the intestinal level, genome-wide gene expression profiling by microarray hybridization identified 601 differentially expressed transcripts (287 upregulated, 314 downregulated) in gut lymphocytes of C. longa-fed chickens compared with nonsupplemented controls. Based on the known functions of the corresponding mammalian genes, the C. longa-induced intestinal transcriptome was mostly associated with genes mediating anti-inflammatory effects. Taken together, these results suggest that dietary C. longa could be used to attenuate Eimeria-induced, inflammation-mediated gut damage in commercial poultry production.

Chlorine Dioxide Disinfection in the Use of Individual Water Purification Devices

Science.gov (United States)

2006-03-01

CTs ranging from 1.7-17.6 mg-min/L necessary for 2-log Giardia muris cyst inactivation (reference 23). The SWTR provides the following CT values...reference 3). A comparison of CTs required for a 2-log inactivation for E. Coli bacteria, Poliovirus 1, and Giardia cysts showed Giardia cysts were 2-5...Cryptosporidium oocysts are the most resistant, being 8-16 times more resistant than Giardia cysts (reference 5). Chlorine dioxide’s general disinfection

Detection of Carbapenemase Production in a Collection of Enterobacteriaceae with Characterized Resistance Mechanisms from Clinical and Environmental Origins by Use of Both Carba NP and Blue-Carba Tests.

Science.gov (United States)

García-Fernández, Sergio; Morosini, María-Isabel; Gijón, Desirèe; Beatobe, Lorena; Ruiz-Garbajosa, Patricia; Domínguez, Lucas; Cantón, Rafael; Valverde, Aránzazu

2016-02-01

Rapid-screening methods to confirm the presence of resistance mechanisms in multidrug-resistant bacteria are currently recommended. Carba NP and Blue-Carba tests were evaluated in carbapenemase-producing Enterobacteriaceae from hospital (n = 102) and environmental (n = 57) origins for detecting the different molecular classes among them. Both methods showed to be fast and cost-effective, with high sensitivity (98% to 100%) and specificity (100%), and may be easily introduced in the routine laboratory. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

ENVIRONMENTAL MONITORING OF LEAKS USING TIME LAPSED LONG ELECTRODE ELECTRICAL RESISTIVITY

International Nuclear Information System (INIS)

Myers, D.A.; Rucker, D.F.; Fink, J.B.; Loke, M.H.

2009-01-01

Highly industrialized areas pose challenges for surface electrical resistivity characterization due to metallic infrastructure. The infrastructure is typically more conductive than the desired targets and will mask the deeper subsurface information. These challenges may be minimized if steel-cased wells are used as long electrodes in the area near the target. We demonstrate a method of using long electrodes to electrically monitor a simulated leak from an underground storage tank with both synthetic examples and a field demonstration. The synthetic examples place a simple target of varying electrical properties beneath a very low resistivity layer. The layer is meant to replicate the effects of infrastructure. Both surface and long electrodes are tested on the synthetic domain. The leak demonstration for the field experiment is simulated by injecting a high conductivity fluid in a perforated well within the S tank farm at Hanford, and the resistivity measurements are made before and after the leak test. All data are processed in four dimensions, where a regularization procedure is applied in both the time and space domains. The synthetic test case shows that the long electrode ERM could detect relative changes in resistivity that are commensurate with the differing target properties. The surface electrodes, on the other hand, had a more difficult time matching the original target's footprint. The field results shows a lowered resistivity feature develop south of the injection site after cessation of the injections. The time lapsed regularization parameter has a strong influence on the differences in inverted resistivity between the pre and post injection datasets, but the interpretation of the target is consistent across all values of the parameter. The long electrode ERM method may provide a tool for near real-time monitoring of leaking underground storage tanks.

Environmental Monitoring Of Leaks Using Time Lapsed Long Electrode Electrical Resistivity

International Nuclear Information System (INIS)

Rucker, D.F.; Fink, J.B.; Loke, M.H.; Myers, D.A.

2009-01-01

Highly industrialized areas pose significant challenges for surface based electrical resistivity characterization and monitoring due to the high degree of metallic infrastructure. The infrastructure is typically several orders of magnitude more conductive than the desired targets, preventing the geophysicist from obtaining a clear picture of the subsurface. These challenges may be minimized if steel-cased wells are used as long electrodes. We demonstrate a method of using long electrodes in a complex nuclear waste facility to monitor a simulated leak from an underground storage tank. The leak was simulated by injecting high conductivity fluid in a perforated well and the resistivity measurements were made before and after the leak test. The data were processed in four dimensions, where a regularization procedure was applied in both the time and space domains. The results showed a lowered resistivity feature develop south of the injection site. The time lapsed regularization parameter had a strong influence on the differences in inverted resistivity between the pre and post datasets, potentially making calibration of the results to specific hydrogeologic parameters difficult.

An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats

NARCIS (Netherlands)

Cornelissen, J.B.W.J.; Giessen, van der J.W.B.; Takumi, K.; Teunis, P.F.M.; Wisselink, H.J.

2014-01-01

High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment.

Evaluation of different methods to recover methicillin-resistant Staphylococcus aureus from hospital environmental surfaces.

LENUS (Irish Health Repository)

Dolan, A

2011-11-01

The environment is implicated as a source of healthcare-associated infections (HAIs) and there is a need for evidence-based approaches to environmental sampling to assess cleanliness and improve infection prevention and control. We assessed, in vitro, different approaches to sampling the environment for meticillin-resistant Staphylococcus aureus (MRSA). In a laboratory-based investigation, the recovery of MRSA from two common hospital environments using six different sampling methods was evaluated, with a wild-type strain of MRSA. A 100 cm(2) section of mattress and a laboratory bench surface were contaminated with known inocula of MRSA. Bacteria were recovered by sampling at 30 min after inoculation, using either saline-moistened cotton swabs, neutralising buffer swabs, eSwabs or macrofoam swabs, which were all enriched in tryptone soya broth, or by sampling with direct contact plates or chromogenic \\'sweep\\' plates. The sensitivity (i.e. the minimum number of bacteria inoculated on to a surface which subsequently produced a positive result) of each method was determined for each surface. The most sensitive methods were eSwabs and macrofoam swabs, requiring 6.1 × 10(-1) and 3.9 × 10(-1) MRSA\\/cm(2), respectively, to produce a positive result from the bench surface. The least sensitive swabbing method was saline-moistened cotton swabs, requiring 1.1 × 10(3) MRSA\\/cm(2) of mattress. The recovery of bacteria from environmental samples varies with the swabs and methodology used and negative culture results do not exclude a pathogen-free environment. Greater standardisation is required to facilitate the assessment of cleanliness of healthcare environments.

Prevalence and molecular characterisation of Eimeria species in Ethiopian village chickens.

Science.gov (United States)

Luu, Lisa; Bettridge, Judy; Christley, Robert M; Melese, Kasech; Blake, Damer; Dessie, Tadelle; Wigley, Paul; Desta, Takele T; Hanotte, Olivier; Kaiser, Pete; Terfa, Zelalem G; Collins, Marisol; Lynch, Stacey E

2013-10-15

may be frequently detected in faecal samples from village chickens in Ethiopia. Co-infection with multiple Eimeria spp was common and almost half of Eimeria positive birds had at least one highly pathogenic species detected. Despite this, all sampled birds were free of overt disease. Although there was no evidence of a difference in the prevalence of oocysts in faecal samples between study regions, there was evidence of variation in the prevalence of some species, perhaps suggesting regional differences in exposure to risk factors associated with the birds, their management and/or location-specific environmental and ecological factors.

Low overlap between carbapenem resistant Pseudomonas aeruginosa genotypes isolated from hospitalized patients and wastewater treatment plants.

Directory of Open Access Journals (Sweden)

Andrej Golle

Full Text Available The variability of carbapenem-resistant Pseudomonas aeruginosa strains (CRPA isolated from urine and respiratory samples in a large microbiological laboratory, serving several health care settings, and from effluents of two wastewater treatment plants (WWTP from the same region was assessed by PFGE typing and by resistance to 10 antibiotics. During the 12-month period altogether 213 carbapenem-resistant P. aeruginosa isolates were cultured and distributed into 65 pulsotypes and ten resistance profiles. For representatives of all 65 pulsotypes 49 different MLSTs were determined. Variability of clinical and environmental strains was comparable, 130 carbapenem-resistant P. aeruginosa obtained from 109 patients were distributed into 38 pulsotypes, while 83 isolates from WWTPs were classified into 31 pulsotypes. Only 9 pulsotypes were shared between two or more settings (hospital or WWTP. Ten MLST were determined for those prevalent pulsotypes, two of them (ST111 and ST235 are among most successful CRPA types worldwide. Clinical and environmental carbapenem-resistant P. aeruginosa strains differed in antibiotic resistance. The highest proportion of clinical isolates was resistant to piperacillin/tazobactam (52.3% and ceftazidime (42.3%. The highest proportion of environmental isolates was resistant to ceftazidime (37.1% and ciprofloxacin (35.5%. The majority of isolates was resistant only to imipenem and/or meropenem. Strains with additional resistances were distributed into nine different patterns. All of them included clinically relevant strains, while environmental strains showed only four additional different patterns.

Seroprevalence of Toxoplasma gondii infection in feral cats in Qatar.

Science.gov (United States)

Boughattas, Sonia; Behnke, Jerzy; Sharma, Aarti; Abu-Madi, Marawan

2017-01-18

Cats are essential in the life cycle of Toxoplasma gondii as they can shed the environmentally resistant oocysts after acquiring infection. Human populations living in cities with high densities of feral cats are therefore likely to be at risk of infection. The current study is the first to estimate the seroprevalence of T. gondii in the feral cat population in Qatar. We investigated the seroprevalence of T. gondii among 495 adult cats from urban and suburban districts in Qatar. Using results from the Modified Agglutination Test, we fitted statistical models with host sex, area and season as explanatory factors and seropositivity as the outcome. The analysis revealed an overall seroprevalence of 82%. Seroprevalence was significantly higher in the summer season (P = 0.006). No significant difference was detected (P > 0.05) between seroprevalence in female and male cats and in cats from urban and suburban districts of Qatar. Despite the seasonal difference, the observed seroprevalence of T. gondii suggests high environmental contamination throughout the year, with some female cats generating more intense responses compared to males. Both findings merit further investigations.

Plasmid-mediated quinolone resistance; interactions between human, animal and environmental ecologies

Directory of Open Access Journals (Sweden)

Laurent ePOIREL

2012-02-01

Full Text Available Resistance to quinolones and fluoroquinolones is being increasingly reported among human but also veterinary isolates during the last two to three decades, very likely as a consequence of the large clinical usage of those antibiotics. Even if the principle mechanisms of resistance to quinolones are chromosome-encoded, due to modifications of molecular targets (DNA gyrase and topoisomerase IV, decreased outer-membrane permeability (porin defect and overexpression of naturally-occurring efflux, the emergence of plasmid-mediated quinolone resistance (PMQR has been reported since 1998. Although these PMQR determinants confer low-level resistance to quinolones and/or fluoroquinolones, they are a favorable background for selection of additional chromosome-encoded quinolone resistance mechanisms. Different transferable mechanisms have been identified, corresponding to the production of Qnr proteins, of the aminoglycoside acetyltransferase AAC(6’-Ib-cr, or of the QepA-type or OqxAB-type efflux pumps. Qnr proteins protect target enzymes (DNA gyrase and type IV topoisomerase from quinolone inhibition (mostly nalidixic acid. The AAC(6’-Ib-cr determinant acetylates several fluoroquinolones, such as norfloxacin and ciprofloxacin. Finally, the QepA and OqxAB efflux pumps extrude fluoroquinolones from the bacterial cell. A series of studies have identified the environment to be a reservoir of PMQR genes, with farm animals and aquatic habitats being significantly involved. In addition, the origin of the qnr genes has been identified, corresponding to the waterborne species Shewanella sp. Altogether, the recent observations suggest that the aquatic environment might constitute the original source of PMQR genes, that would secondly spread among animal or human isolates.

Determination of antifungal susceptibility patterns among the environmental isolates of Aspergillus fumigatus in Iran

Directory of Open Access Journals (Sweden)

Faezeh Mohammadi

2016-01-01

Conclusion: Our findings demonstrated that there was not azole-resistant among environmental isolates of A. fumigatus. Medical triazoles compounds have structural similarity with triazole fungicide compounds in agriculture, therefore, resistance development through exposure to triazole fungicide compounds in the environment is important but it sounds there is not a serious health problem in drug resistance in environmental isolates in Iran.

Microbiological indicators of water quality in the Xochimilco canals, Mexico City.

Science.gov (United States)

Juárez-Figueroa, Luis Alfredo; Silva-Sánchez, Jesús; Uribe-Salas, Felipe Javier; Cifuentes-García, Enrique

2003-01-01

To quantify microbiology indicators of fecal contamination in the effluents of two waste water treatment plants and in samples collected in several canals in Xochimilco. A cross sectional study was performed. Ten sites, 5 from plant effluents and 5 from canals, were selected for sampling during November and December 2001. Fecal coliforms and enterococci were quantified by membrane filtration, male specific (F+) and somatic coliphages by double agar layer technique, and Cryptosporidium oocysts and Giardia cysts by concentration with Envirocheck filter followed by immunofluorescence microscopy quantification. The average of organisms counts from effluents and canal water were compared with t Student test. Treated water discharge in canals showed a low count of Fecal Coliforms (average 40.4/100 ml), enterococci (average 58.8/100 ml) and Cryptosporidium oocysts (average 13.2/100 l), while coliphages and Giardia cyst rendered higher counts (average 1467.5/100 ml and 1199.8/100 l, respectively) suggesting the water treatment methods could fail to remove these agents. A significant lower count of Giardia cysts (average 45/100 l) and no Cryptosporidium oocysts were found in irrigation canals, which suggests a natural clearance of these pathogens. Strains of Escherichia coli isolated in one of the canals contaminated with sewage had antimicrobial multi-resistance that was transferred by conjugation suggesting that resistance is encoded in a plasmid potentially transferable to other pathogenic bacteria. Cost effective and culturally acceptable waste treatment methods will require careful planning and consultation if they are to be adopted and mantained by local populations.

Current trends of human infections and antibiotic resistance of the genus Shewanella.

Science.gov (United States)

Yousfi, K; Bekal, S; Usongo, V; Touati, A

2017-08-01

Shewanella spp. are commonly known as environmental bacteria and are most frequently isolated from aquatic areas. Currently, diseases syndromes and multidrug resistance have increasingly been reported in the genus Shewanella. Some species are associated with various infections, such as skin and soft tissue infections, as well as bacteremia. Generally, these bacteria are opportunistic and mostly affect people with an impaired immune system. This genus is also a probable vehicle and progenitor of antibiotic resistance genes. In fact, several resistance genes and mobile genetic elements have been identified in some resistant species isolated from environmental or clinical settings. These genes confer resistance to different antibiotic classes, including those used in therapies such as β-lactams and quinolones, and are generally located on the chromosome. Recently, a multidrug-resistant (MDR) plasmid harboring several drug resistance genes associated with transposons and integrons has been identified in Shewanella xiamenensis. These antibiotic resistance genes can circulate in the environment and contribute to the emergence of antibiotic resistance. This review describes different aspects of Shewanella, focusing on the infections caused by this genus, as well as their role in the propagation of antibiotic resistance via mobile genetic elements.

Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System.

Directory of Open Access Journals (Sweden)

Jacek Panek

Full Text Available Spoilage of heat processed food and beverage by heat resistant fungi (HRF is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700, the other from thermal processed strawberry product in 2012 (KC179765, used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods.

The impact of triclosan on the spread of antibiotic resistance in the environment

Directory of Open Access Journals (Sweden)

Daniel E Carey

2015-01-01

Full Text Available Triclosan (TCS is a commonly used antimicrobial agent that enters wastewater treatment plants (WWTPs and the environment. An estimated 1.1x105 to 4.2x105 kg of TCS are discharged from these WWTPs per year in the United States. The abundance of TCS along with its antimicrobial properties have given rise to concern regarding its impact on antibiotic resistance in the environment. The objective of this review is to assess the state of knowledge regarding the impact of TCS on multidrug resistance in environmental settings, including engineered environments such as anaerobic digesters. Pure culture studies are reviewed in this paper to gain insight into the substantially smaller body of research surrounding the impacts of TCS on environmental microbial communities. Pure culture studies, mainly on pathogenic strains of bacteria, demonstrate that TCS is often associated with multidrug resistance. Research is lacking to quantify the current impacts of TCS discharge to the environment, but it is known that resistance to TCS and multidrug resistance can increase in environmental microbial communities exposed to TCS. Research plans are proposed to quantitatively define the conditions under which TCS selects for multidrug resistance in the environment.

Oocyst shedding by green-winged-saltator (Saltator similis in the diagnostic of coccidiosis and Isospora similisi n. sp. (Apicomplexa: Eimeriidae Eliminação de oocistos por trinca-ferro-verdadeiro (Saltator similis no diagnóstico da coccidiose e Isospora similisi n. sp. (Apicomplexa: Eimeriidae

Directory of Open Access Journals (Sweden)

Cleide Domingues Coelho

2013-03-01

Full Text Available Diurnal periodicity is a phenomenon that has been observed in coccidian of Isospora parasites of passerines, which have been eliminated great number of oocysts at dusk. The objective of this study was to evaluate the occurrence of periodicity of oocysts presence in the green-winged-saltator Saltator similis, and its use in the diagnosis of coccidiosis in wild birds in captivity. A total of 220 fecal samples were collected from birds, apprehended from illegal trading and kept in quarantine in CETAS∕IBAMA, in the morning and late afternoon, from May to November 2010. It was observed that 1.82% of the samples collected in the morning were positive, while 31.36% of samples were positive in the late afternoon. In addition, the number of oocysts shed was greater in the afternoon. Therefore, it was concluded that the sampling in the late afternoon provided greater reliability for the diagnosis of coccidiosis in green-winged-saltators. Moreover, in this study a new isosporoid coccidian parasite from the green-winged-saltator S. similis was observed and is herein described. Isospora similisi n. sp. oocysts are spheroidal to sub-spheroidal, 27.5 × 25.9 µm, with a smooth and bi-layered wall, ∼1.2 mm. Micropyle and oocyst residuum are absent, but splinter-like or comma-like granules are present. Sporocysts are ellipsoidal or slightly ovoidal, 17.4 × 12.2 mm. A stieda body and substieda body are present. The sporocyst residuum is composed of granules of different sizes. Sporozoites are vermiform with a single refractile body and a nucleus. This is the fourth description of an isosporoid coccidium infecting S. similis and the sixth description from Cardinalidae.A periodicidade diurna é um fenômeno que tem sido observado em coccídios do gênero Isospora parasitas de pássaros, os quais eliminam uma maior quantidade de oocistos ao entardecer. O objetivo deste estudo foi determinar a periodicidade de eliminação de oocistos pelas fezes no trinca

Persistent environmental contamination with USA300 methicillin-resistant Staphylococcus aureus and other pathogenic strain types in households with S. aureus skin infections.

Science.gov (United States)

Eells, Samantha J; David, Michael Z; Taylor, Alexis; Ortiz, Nancy; Kumar, Neha; Sieth, Julia; Boyle-Vavra, Susan; Daum, Robert S; Miller, Loren G

2014-11-01

To understand the genotypic spectrum of environmental contamination of Staphylococcus aureus in households and its persistence. Prospective longitudinal cohort investigation. Index participants identified at 2 academic medical centers. Adults and children with S. aureus skin infections and their household contacts in Los Angeles and Chicago. Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing. We enrolled 346 households, 88% of which completed the 3-month follow-up visit. S. aureus environmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistant S. aureus (MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject's infection isolate were body colonization by any household member with the index subject's infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75-20.79]), higher housing density (OR, 1.47 [95% CI, 1.10-1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16-2.27]). Household environmental contamination with the index subject's infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject's infection strain. We found that infecting S. aureus isolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenic S. aureus strain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.

Emissie van Cryptosporidium en Giardia door landbouwhuisdieren

NARCIS (Netherlands)

Schrijven JF; Bruin HAM de; Engels GB; Leenen EJTM; MGB

1999-01-01

In this study, the relative contributions of the pathogenic protozoa Cryptosporidium and Giardia by manure of farm animals in The Netherlands to the total yearly environmental load was studied. Manure of veal calves forms a very large source of Cryptosporidium (1.5 m 10 square 16 oocysts per year)

Towards a research agenda for water, sanitation and antimicrobial resistance

NARCIS (Netherlands)

Wuijts, Susanne; van den Berg, Harold H J L; Miller, Jennifer; Abebe, Lydia; Sobsey, Mark; Andremont, Antoine; Medlicott, Kate O; van Passel, Mark W J; de Roda Husman, Ana Maria

Clinically relevant antimicrobial resistant bacteria, genetic resistance elements, and antibiotic residues (so-called AMR) from human and animal waste are abundantly present in environmental samples. This presence could lead to human exposure to AMR. In 2015, the World Health Organization (WHO)

Effect of Spacecraft Environmental Variables on the Flammability of Fire Resistant Fabrics

Science.gov (United States)

Osorio, A. F.; Fernandez-Pello, C.; Takahashi, S.; Rodriguez, J.; Urban, D. L.; Ruff, G.

2012-01-01

Fire resistant fabrics are used for firefighter, racecar drivers as well as astronaut suits. However, their fire resistant characteristics depend on the environment conditions and require study. Particularly important is the response of these fabrics to elevated oxygen concentration environments and radiant heat from a source such as an adjacent fire. In this work, experiments using two fire resistant fabrics were conducted to study the effect of oxygen concentration, external radiant flux and oxidizer flow velocity in concurrent flame spread. Results show that for a given fabric the minimum oxygen concentration for flame spread depends strongly on the magnitude of the external radiant flux. At increased oxygen concentrations the external radiant flux required for flame spread decreases. Oxidizer flow velocity influences the external radiant flux only when the convective heat flux from the flame has similar values to the external radiant flux. The results of this work provide further understanding of the flammability characteristics of fire resistant fabrics in environments similar to those of future spacecrafts.

Antibiotic resistant pattern of environmental isolates of Listeria ...

African Journals Online (AJOL)

SERVER

2007-09-19

Sep 19, 2007 ... Department of Microbiology, University of Ado-Ekiti, P.M.B. 5363, Ado-Ekiti, Nigeria. Accepted 26 January ... if not all, environmental isolates of L. monocytogenes are virulent and ..... Bergey Manual of Systematic. Bacteriology ...

Effects of Metals on Antibiotic Resistance and Conjugal Plasmid Transfer in Soil Bacterial Communities

DEFF Research Database (Denmark)

Song, Jianxiao

Antibiotic resistance currently represents one of the biggest challenges for human health and in recent years the environmental dimension of antibiotic resistance has been increasingly recognized. The soil environment serves as an important reservoir of antibiotic resistance determinants. In addi...... adaptation to metal stress did not significantly increase the permissiveness of the soil bacterial community towards conjugal plasmid transfer........ In addition to direct selection of antibiotic resistance by antibiotics, metals may co-select for antibiotic resistance via different mechanisms causing environmental selection of antibiotic resistance in metal contaminated soils. Horizontal gene transfer of mobile genetic elements (MGEs) like plasmids...... is generally considered one of the most important co-selection mechanisms as multiple resistance genes can be located on the same MGE. This PhD thesis focused on the impact of metals (Cu and Zn) on the development of antibiotic resistance in bacterial communities in soils exposed to different degrees...

Plant resistance to cold stress: Mechanisms and environmental ...

Indian Academy of Sciences (India)

Unknown

Cold acclimation of plants; environmental signals; frost hardening; photoperiod; phytochrome; Scots pine http://www.ias.ac.in/jbiosci .... radical scavenging potential of the cells (Tao et al 1998; ...... tion in cell–free extracts; FEBS Lett. 410 206– ...

Influence of Temperature and Humidity on Bakelite Resistivity

CERN Document Server

Arnaldi, R; Barret, V; Bastid, N; Blanchard, G; Chiavassa, E; Cortese, P; Crochet, Philippe; Dellacasa, G; De Marco, N; Dupieux, P; Espagnon, B; Fargeix, J; Ferretti, A; Gallio, M; Lamoine, L; Luquin, Lionel; Manso, F; Mereu, P; Métivier, V; Musso, A; Oppedisano, C; Piccotti, A; Rahmani, A; Royer, L; Roig, O; Scalas, E; Scomparin, E; Vercellin, Ermanno

1999-01-01

Presentation made at RPC99 and submitted to Elsevier PreprintThe use of phenolic or melaminic bakelite as RPC electrodes is widespread. The electrode resistivity is an important parameter for the RPC performance. As recent studies have pointed out, the bakelite resistivity changes with temperature and is influenced by humidity. In order to gain a quantitative understanding on the influence of temperature and humidity on RPC electrodes, we assembled an apparatus to measure resistivity in well-controlled conditions. A detailed description of the experimental set-up as well as the first resistivity measurements for various laminates in different environmental conditions are presented.

Rethinking vector immunology: the role of environmental temperature in shaping resistance

OpenAIRE

Murdock, Courtney C.; Paaijmans, Krijn P.; Cox-Foster, Diana; Read, Andrew F.; Thomas, Matthew B.

2012-01-01

Recent ecological research has revealed that environmental factors can strongly affect insect immunity and influence the outcome of host–parasite interactions. To date, however, most studies examining immune function in mosquitoes have ignored environmental variability. We argue that one such environmental variable, temperature, influences both vector immunity and the parasite itself. As temperatures in the field can vary greatly from the ambient temperature in the laboratory, it will be esse...

Carbapenem-Resistant Acinetobacter baumannii: Concomitant Contamination of Air and Environmental Surfaces.

Science.gov (United States)

Shimose, Luis A; Masuda, Eriko; Sfeir, Maroun; Berbel Caban, Ana; Bueno, Maria X; dePascale, Dennise; Spychala, Caressa N; Cleary, Timothy; Namias, Nicholas; Kett, Daniel H; Doi, Yohei; Munoz-Price, L Silvia

2016-07-01

OBJECTIVE To concomitantly determine the differential degrees of air and environmental contamination by Acinetobacter baumannii based on anatomic source of colonization and type of ICU layout (single-occupancy vs open layout). DESIGN Longitudinal prospective surveillance study of air and environmental surfaces in patient rooms. SETTING A 1,500-bed public teaching hospital in Miami, Florida. PATIENTS Consecutive A. baumannii-colonized patients admitted to our ICUs between October 2013 and February 2014. METHODS Air and environmental surfaces of the rooms of A. baumannii-colonized patients were sampled daily for up to 10 days. Pulsed-field gel electrophoresis (PFGE) was used to type and match the matching air, environmental, and clinical A. baumannii isolates. RESULTS A total of 25 A. baumannii-colonized patients were identified during the study period; 17 were colonized in the respiratory tract and 8 were colonized in the rectum. In rooms with rectally colonized patients, 38.3% of air samples were positive for A. baumannii; in rooms of patients with respiratory colonization, 13.1% of air samples were positive (P=.0001). In rooms with rectally colonized patients, 15.5% of environmental samples were positive for A. baumannii; in rooms of patients with respiratory colonization, 9.5% of environmental samples were positive (P=.02). The rates of air contamination in the open-layout and single-occupancy ICUs were 17.9% and 21.8%, respectively (P=.5). Environmental surfaces were positive in 9.5% of instances in open-layout ICUs versus 13.4% in single-occupancy ICUs (P=.09). CONCLUSIONS Air and environmental surface contaminations were significantly greater among rectally colonized patients; however, ICU layout did not influence the rate of contamination. Infect Control Hosp Epidemiol 2016;37:777-781.

Effects of 60Co gamma irradiation on Eimeria falciformis (Eimer 1870) Schneider 1875, a protozoan parasite of the mouse, Mus musculus L

International Nuclear Information System (INIS)

Wright, A.C.

1976-01-01

Oocysts of an E. falciformis strain first isolated in Wuppertal, Germany were exposed to cobalt-60 gamma radiation under different conditions of oocyst age and development. In order to construct survival curves for oocysts irradiated in the unsporulated state, normalized percent sporulation was plotted as a function of radiation dose. Oocysts irradiated in the sporulated state never caused infection after receiving doses of 50 krads or more. Rarely, oocysts which had received 40 krads produced infection and completed their life cycle in susceptible hosts, but usually the doses beyond which infection did not occur ranged from 30 to 35 krads. Immunity was shown best by hosts which had received unirradiated oocysts in vaccinations prior to challenge. When irradiated sporulated oocysts were used in attempts to immunize susceptible hosts against coccidiosis, the most positive results were obtained from oocysts which had been exposed to 20 krads. Animals receiving vaccinations of oocysts exposed to 20 krads always survived the minimal infections caused by vaccination and also exhibited good immunity to challenge

40 CFR 157.30 - Voluntary use of child-resistant packaging.

Science.gov (United States)

2010-07-01

... packaging. 157.30 Section 157.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PACKAGING REQUIREMENTS FOR PESTICIDES AND DEVICES Child-Resistant Packaging § 157.30 Voluntary use of child-resistant packaging. A registrant whose product is not required to be in child...

Alternative mounting media for preservation of some protozoa.

Science.gov (United States)

Criado-Fornelio, A; Heredero-Bermejo, I; Pérez-Serrano, J

2014-10-01

Protozoa resistant stages are disintegrated when mounted in toluene-based media. To overcome such problem, three toluene-free mountants were tested on preserve Acanthamoeba spp and gregarines. Two commercial glues based on cyanoacrylate or trimethoxysilane were suitable for preserving both cysts and trophozoites. Hoyer's medium showed good results for mounting gregarine oocysts. Copyright © 2014 Elsevier B.V. All rights reserved.

Regional Environmental Non-Governmental Organizations: Between Resistance and Utopia, Some Reflections.

Directory of Open Access Journals (Sweden)

Jussara da Silva Tavares

2015-01-01

Full Text Available This paper has as its main objective the comprehension and analysis of the environmental action effectiveness of Non-Governmental Organizations (NGOs which are inserted in the region of the Hydrographic Basins of rivers "Turvo" and "Grande", and their relation with the others who act in this interactive field in order to understand what is being built in these regions considering the environmental issue. Material and Methodology: direct research in the selected NGOs and bibliographic review: NGOs, environmental legislation and participative democracy. Results: Participation in the survey data for the diagnosis of the current situation of hydric resource and the establishment of guidelines for the Plan of Hydrographic Basins of "Turvo" and "Grande" – Report Zero and in the Basins of "Turvo" and "Grande" Committee, actions in Environmental Education and reforestation/revegetation of part of the riparian forest and the protection of water sources. Conclusion: The environmental NGOs have played the protagonist role in the process of social transformation, with representativeness and competence to add people, institutions and resources to defend environment. Their acts show evidences that it's possible to overcome the environmental damages and they contribute to a reflection about the environment, means of organization and popular participation. The NGOs actions are often blocked by the game of interests that feeds the backstage of environmental matter. Business people pressure, lack of political will from the politicians to break the favor culture that was taken forward in relation to big interests; all these factors take part in the inhibition circuit that hinders the NGOs acts many times.

Association of Antibiotic Resistance in Agricultural Escherichia coli Isolates with Attachment to Quartz▿

Science.gov (United States)

Liu, Ping; Soupir, Michelle L.; Zwonitzer, Martha; Huss, Bridgette; Jarboe, Laura R.

2011-01-01

Surface water can be contaminated by bacteria from various sources, including manure from agricultural facilities. Attachment of these bacteria to soil and organic particles contributes to their transport through the environment, though the mechanism of attachment is unknown. As bacterial attachment to human tissues is known to be correlated with antibiotic resistance, we have investigated here the relationship between bacterial attachment to environmental particles and antibiotic resistance in agricultural isolates. We evaluated 203 Escherichia coli isolates collected from swine facilities for attachment to quartz, resistance to 13 antibiotics, and the presence of genes encoding 13 attachment factors. The genes encoding type I, EcpA, P pili, and Ag43 were detected, though none was significantly related to attachment. Quartz attachment was positively and significantly (P amoxicillin/streptomycin/tetracycline/sulfamethazine/tylosin/chlortetracycline and negatively and significantly (P < 0.0038) related to combined resistance to nalidixic acid/kanamycin/neomycin. These results provide clear evidence for a link between antibiotic resistance and attachment to quartz in agricultural isolates. We propose that this may be due to encoding by the responsible genes on a mobile genetic element. Further exploration of the relationship between antibiotic resistance and attachment to environmental particles will improve the understanding and modeling of environmental transport processes, with the goal of preventing human exposure to antibiotic-resistant or virulent microorganisms. PMID:21821756

Association of antibiotic resistance in agricultural Escherichia coli isolates with attachment to quartz.

Science.gov (United States)

Liu, Ping; Soupir, Michelle L; Zwonitzer, Martha; Huss, Bridgette; Jarboe, Laura R

2011-10-01

Surface water can be contaminated by bacteria from various sources, including manure from agricultural facilities. Attachment of these bacteria to soil and organic particles contributes to their transport through the environment, though the mechanism of attachment is unknown. As bacterial attachment to human tissues is known to be correlated with antibiotic resistance, we have investigated here the relationship between bacterial attachment to environmental particles and antibiotic resistance in agricultural isolates. We evaluated 203 Escherichia coli isolates collected from swine facilities for attachment to quartz, resistance to 13 antibiotics, and the presence of genes encoding 13 attachment factors. The genes encoding type I, EcpA, P pili, and Ag43 were detected, though none was significantly related to attachment. Quartz attachment was positively and significantly (P amoxicillin/streptomycin/tetracycline/sulfamethazine/tylosin/chlortetracycline and negatively and significantly (P < 0.0038) related to combined resistance to nalidixic acid/kanamycin/neomycin. These results provide clear evidence for a link between antibiotic resistance and attachment to quartz in agricultural isolates. We propose that this may be due to encoding by the responsible genes on a mobile genetic element. Further exploration of the relationship between antibiotic resistance and attachment to environmental particles will improve the understanding and modeling of environmental transport processes, with the goal of preventing human exposure to antibiotic-resistant or virulent microorganisms.

Occurrence and Distribution of Antibiotic-resistant Bacteria and Transfer of Resistance Genes in Lake Taihu

Science.gov (United States)

Yin, Qian; Yue, Dongmei; Peng, Yuke; Liu, Ying; Xiao, Lin

2013-01-01

The overuse of antibiotics has accelerated antibiotic resistance in the natural environment, especially fresh water, generating a potential risk for public health around the world. In this study, antibiotic resistance in Lake Taihu was investigated and this was the first thorough data obtained through culture-dependent methods. High percentages of resistance to streptomycin and ampicillin among bacterial isolates were detected, followed by tetracycline and chloramphenicol. Especially high levels of ampicillin resistance in the western and northern regions were illustrated. Bacterial identification of the isolates selected for further study indicated the prevalence of some opportunistic pathogens and 62.0% of the 78 isolates exhibited multiple antibiotic resistance. The presence of ESBLs genes was in the following sequence: blaTEM > blaSHV > blaCTMX and 38.5% of the isolates had a class I integrase gene. Of all tested strains, 80.8% were able to transfer antibiotic resistance through conjugation. We also concluded that some new families of human-associated ESBLs and AmpC genes can be found in natural environmental isolates. The prevalence of antibiotic resistance and the dissemination of transferable antibiotic resistance in bacterial isolates (especially in opportunistic pathogens) was alarming and clearly indicated the urgency of realizing the health risks of antibiotic resistance to human and animal populations who are dependent on Lake Taihu for water consumption. PMID:24240317

Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam.

Science.gov (United States)

Lien, La Thi Quynh; Lan, Pham Thi; Chuc, Nguyen Thi Kim; Hoa, Nguyen Quynh; Nhung, Pham Hong; Thoa, Nguyen Thi Minh; Diwan, Vishal; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia

2017-06-29

The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the bla TEM gene being more common than bla CTX-M . Co-harbouring of the bla CTX-M , bla TEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America.

Directory of Open Access Journals (Sweden)

Marinely Bustamante Gomez

2016-03-01

Full Text Available A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables.A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD50 showed a strong linear relationship with the corresponding resistance ratio (RR50. The statistical descriptive analysis of showed that the frequency distribution of the Log (LD50 is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD50 groups with a particular concentration of the highest LD50 populations over the region identified as the putative center of dispersion of T. infestans.The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans

Contamination of the Clinical Microbiology Laboratory with Vancomycin-Resistant Enterococci and Multidrug- Resistant Enterobacteriaceae: Implications for Hospital and Laboratory Workers

Science.gov (United States)

Collins, Susan M.; Hacek, Donna M.; Degen, Lisa A.; Wright, Marc O.; Noskin, Gary A.; Peterson, Lance R.

2001-01-01

We surveyed environmental surfaces in our clinical microbiology laboratory to determine the prevalence of vancomycin-resistant enterococci (VRE) and multidrug-resistant Enterobacteriaceae (MDRE) during a routine working day. From a total of 193 surfaces, VRE were present on 20 (10%) and MDRE were present on 4 (2%) of the surfaces tested. In a subsequent survey after routine cleaning, all of the 24 prior positive surfaces were found to be negative. Thus, those in the laboratory should recognize that many surfaces may be contaminated by resistant organisms during routine processing of patient specimens. PMID:11574615

The benefits of herbicide-resistant crops.

Science.gov (United States)

Green, Jerry M

2012-10-01

Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry.

The Ability of Tourist Natural Trails to Resist Tourism Load and Possibilities for Reducing the Environmental Impacts : Case Study of the Slovak Paradise National Park (Slovakia

Directory of Open Access Journals (Sweden)

Janočková Jana

2015-09-01

Full Text Available The strictly protected natural area of Sucha Bela Gorge, located in the Slovak Paradise National Park, Slovakia, is exposed to environmental degradation by heavy tourist loads. Although educational and technical measures have been put in place, there is ongoing debate whether and how to limit the intensity of tourist visits. This study evaluates the ability of the trail leading through the gorge to resist trampling disturbance and to minimise the environmental impacts in the wider area of Sucha Bela by keeping tourists from moving off the designated areas. Aspects of trail layout, geological and geomorphological structures, terrain altering during the summer season, and acceptable tourist flow were investigated.The results show the current development would be acceptable in the case of limited off-trail movement. It therefore seems appropriate to review the trail allocation and marking, and to focus on environmental education rather than on limiting tourist visits.

Flocked nylon swabs versus RODAC plates for detection of multidrug-resistant organisms on environmental surfaces in intensive care units.

Science.gov (United States)

Okamoto, K; Rhee, Y; Schoeny, M; Lolans, K; Cheng, J; Reddy, S; Weinstein, R A; Hayden, M K; Popovich, K J

2018-01-01

To compare two culture methods [nylon fiber flocked swabs with broth enrichment versus RODAC ('replicate organism detection and counting') plates] for recovery of multidrug-resistant organisms, 780 environmental surfaces in 63 rooms of patients on contact precautions in four intensive care units at one hospital were examined. Among sites that had at least one positive culture, swab culture with broth enrichment detected the target organisms more frequently than RODAC plates (37.5% vs 26.0%, P = 0.06). There was moderate agreement between the two methods (κ = 0.44) with agreement better for small or flat surfaces compared to large or irregular surfaces. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Predation and selection for antibiotic resistance in natural environments

DEFF Research Database (Denmark)

Leisner, Jørgen; Jørgensen, Niels O. G.; Middelboe, Mathias

2016-01-01

Genes encoding resistance to antibiotics appear, like the antibiotics themselves, to be ancient, originating long before the rise of the era of anthropogenic antibiotics. However, detailed understanding of the specific biological advantages of antibiotic resistance in natural environments is still...... lacking, thus limiting our efforts to prevent environmental influx of resistance genes. Here, we propose that antibiotic-resistant cells not only evade predation from antibiotic producers but also take advantage of nutrients released from cells that are killed by the antibiotic-producing bacteria. Thus......, predation is potentially an important mechanism for driving antibiotic resistance during slow or stationary phase of growth when nutrients are deprived. This adds to explain the ancient nature and widespread occurrence of antibiotic resistance in natural environments unaffected by anthropogenic antibiotics...

The antibiotic resistance ?mobilome?: searching for the link between environment and clinic

OpenAIRE

Perry, Julie A.; Wright, Gerard D.

2013-01-01

Antibiotic resistance is an ancient problem, owing to the co-evolution of antibiotic-producing and target organisms in the soil and other environments over millennia. The environmental “resistome” is the collection of all genes that directly or indirectly contribute to antibiotic resistance. Many of these resistance determinants originate in antibiotic-producing organisms (where they serve to mediate self-immunity), while others become resistance determinants only when mobilized and over-expr...

Heat-resistant materials 2. Conference proceedings of the 2. international conference on heat-resistant materials

International Nuclear Information System (INIS)

Natesan, K.; Ganesan, P.; Lai, G.Y.

1995-01-01

The Second International Conference on Heat-Resistant Materials was held in Gatlinburg, Tennessee, September 11--14, 1995 and focused on materials performance in cross-cutting technologies where heat resistant materials play a large and sometimes life-and performance-limiting roles in process schemes. The scope of materials for heat-resistant applications included structural iron- and nickel-base alloys, intermetallics, and ceramics. The conference focused on materials development, performance of materials in simulated laboratory and actual service environments on mechanical and structural integrity of components, and state-of-the-art techniques for processing and evaluating materials performance. The three keynote talks described the history of heat-resistant materials, relationship between microstructure and mechanical behavior, and applications of these materials in process schemes. The technical sessions included alloy metallurgy and properties, environmental effects and properties, deformation behavior and properties, relation between corrosion and mechanical properties, coatings, intermetallics, ceramics, and materials for waste incineration. Seventy one papers have been processed separately for inclusion on the data base

Anomaly effects of arrays for 3d geoelectrical resistivity imaging ...

African Journals Online (AJOL)

user

The effectiveness of using a net of orthogonal or parallel sets of two-dimensional (2D) profiles for three- dimensional (3D) geoelectrical resistivity imaging has been evaluated. A series of 2D apparent resistivity data were generated over two synthetic models which represent geological or environmental conditions for a ...

Association of Environmental Contamination in the Home With the Risk for Recurrent Community-Associated, Methicillin-Resistant Staphylococcus aureus Infection.

Science.gov (United States)

Knox, Justin; Sullivan, Sean B; Urena, Julia; Miller, Maureen; Vavagiakis, Peter; Shi, Qiuhu; Uhlemann, Anne-Catrin; Lowy, Franklin D

2016-06-01

The role of environmental contamination in recurrent Staphylococcus aureus infections within households and its potential effect on intervention strategies has been debated recently. To assess whether household environmental contamination increases the risk for recurrent infection among individuals with a community-associated methicillin-resistant S aureus (MRSA) infection. This cohort study was conducted from November 1, 2011, to June 30, 2014, in the Columbia University Medical Center catchment area. All patients within 72 hours of presentation with skin or soft-tissue infections and blood, urine, or sputum cultures positive for MRSA were identified. Two hundred sixty-two patients met study inclusion criteria; 83 of these (31.7%) agreed to participate (index patients) with 214 household members. Participants were followed up for 6 months, and 62 of the 83 households (74.7%) completed follow-up. Participants and researchers were blinded to exposure status throughout the study. Follow-up was completed on June 30, 2014, and data were assessed from July 1, 2014, to February 19, 2016. Concordant environmental contamination, defined as having an isolate with the identical staphylococcal protein A and staphylococcal chromosomal cassette mec type or antibiogram type as the index patient's clinical isolate, present on 1 or more environmental surfaces at the time of a home visit to the index patient after infection. Index recurrent infection, defined as any self-reported infection among the index patients during follow-up. One patient did not complete any follow-up. Of the remaining 82 index patients, 53 (64.6%) were female and 59 (72.0%) were Hispanic. The mean age was 30 (SD, 20; range, 1-79) years. Forty-nine of 61 MRSA infections where the clinical isolate could be obtained (80.3%) were due to the epidemic strain USA300. Among the 82 households in which a patient had an index MRSA infection, the clinical isolate was present in the environment in 20 (24.4%) and not

Emergence and dissemination of antibiotic resistance: A global problem

Directory of Open Access Journals (Sweden)

R Choudhury

2012-01-01

Full Text Available Antibiotic resistance is a major problem in clinical health settings. Interestingly the origin of many of antibiotic resistance mechanisms can be traced back to non-pathogenic environmental organisms. Important factors leading to the emergence and spread of antibiotic resistance include absence of regulation in the use of antibiotics, improper waste disposal and associated transmission of antibiotic resistance genes in the community through commensals. In this review, we discussed the impact of globalisation on the transmission of antibiotic resistance genes in bacteria through immigration and export/import of foodstuff. The significance of surveillance to define appropriate use of antibiotics in the clinic has been included as an important preventive measure.

Engineering insect-resistant crops: A review

African Journals Online (AJOL)

dgeorge

African Journal of Biotechnology ... Transgenic crops engineered for enhanced levels of resistance to insect ... this background that research work targeting other candidate genes such as ... nisms, and potential deleterious environmental effects. ... The global market value of biotech crops was esti- .... located in repeat 11.

Expression of multiple resistance genes enhances tolerance to environmental stressors in transgenic poplar (Populus × euramericana 'Guariento'.

Directory of Open Access Journals (Sweden)

Xiaohua Su

Full Text Available Commercial and non-commercial plants face a variety of environmental stressors that often cannot be controlled. In this study, transgenic hybrid poplar (Populus × euramericana 'Guariento' harboring five effector genes (vgb, SacB, JERF36, BtCry3A and OC-I were subjected to drought, salinity, waterlogging and insect stressors in greenhouse or laboratory conditions. Field trials were also conducted to investigate long-term effects of transgenic trees on insects and salt tolerance in the transformants. In greenhouse studies, two transgenic lines D5-20 and D5-21 showed improved growth, as evidenced by greater height and basal diameter increments and total biomass relative to the control plants after drought or salt stress treatments. The improved tolerance to drought and salt was primarily attributed to greater instantaneous water use efficiency (WUEi in the transgenic trees. The chlorophyll concentrations tended to be higher in the transgenic lines under drought or saline conditions. Transformed trees in drought conditions accumulated more fructan and proline and had increased Fv/Fm ratios (maximum quantum yield of photosystem II under waterlogging stress. Insect-feeding assays in the laboratory revealed a higher total mortality rate and lower exuviation index of leaf beetle [Plagiodera versicolora (Laicharting] larvae fed with D5-21 leaves, suggesting enhanced insect resistance in the transgenic poplar. In field trials, the dominance of targeted insects on 2-year-old D5-21 transgenic trees was substantially lower than that of the controls, indicating enhanced resistance to Coleoptera. The average height and DBH (diameter at breast height of 2.5-year-old transgenic trees growing in naturally saline soil were 3.80% and 4.12% greater than those of the control trees, but these increases were not significant. These results suggested that multiple stress-resistance properties in important crop tree species could be simultaneously improved, although

Intrinsic, adaptive and acquired antimicrobial resistance in Gram-negative bacteria.

Science.gov (United States)

Arzanlou, Mohsen; Chai, Wern Chern; Venter, Henrietta

2017-02-28

Gram-negative bacteria are responsible for a large proportion of antimicrobial-resistant infections in humans and animals. Among this class of bacteria are also some of the most successful environmental organisms. Part of this success is their adaptability to a variety of different niches, their intrinsic resistance to antimicrobial drugs and their ability to rapidly acquire resistance mechanisms. These mechanisms of resistance are not exclusive and the interplay of several mechanisms causes high levels of resistance. In this review, we explore the molecular mechanisms underlying resistance in Gram-negative organisms and how these different mechanisms enable them to survive many different stress conditions. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Metal resistant plants and phytoremediation of environmental contamination

Science.gov (United States)

Meagher, Richard B.; Li, Yujing; Dhankher, Om P.

2010-04-20

The present disclosure provides a method of producing transgenic plants which are resistant to at least one metal ion by transforming the plant with a recombinant DNA comprising a nucleic acid encoding a bacterial arsenic reductase under the control of a plant expressible promoter, and a nucleic acid encoding a nucleotide sequence encoding a phytochelatin biosynthetic enzyme under the control of a plant expressible promoter. The invention also relates a method of phytoremediation of a contaminated site by growing in the site a transgenic plant expressing a nucleic acid encoding a bacterial arsenate reductase and a nucleic acid encoding a phytochelatin biosynthetic enzyme.

NASA's Advanced Environmental Barrier Coatings Development for SiC/SiC Ceramic Matrix Composites: Understanding Calcium Magnesium Alumino-Silicate (CMAS) Degradations and Resistance

Science.gov (United States)

Zhu, Dongming

2014-01-01

Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is essential to the viability and reliability of the envisioned CMC engine component applications, ensuring integrated EBC-CMC system durability and designs are achievable for successful applications of the game-changing component technologies and lifing methodologies.This paper will emphasize recent NASA environmental barrier coating developments for SiCSiC turbine airfoil components, utilizing advanced coating compositions, state-of-the-art processing methods, and combined mechanical and environment testing and durability evaluations. The coating-CMC degradations in the engine fatigue-creep and operating environments are particularly complex; one of the important coating development aspects is to better understand engine environmental interactions and coating life debits, and we have particularly addressed the effect of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the durability of the environmental barrier coating systems, and how the temperature capability, stability and cyclic life of the candidate rare earth oxide and silicate coating systems will be impacted in the presence of the CMAS at high temperatures and under simulated heat flux conditions. Advanced environmental barrier coating systems, including HfO2-Si with rare earth dopant based bond coat systems, will be discussed for the performance improvements to achieve better temperature capability and CMAS resistance for future engine operating conditions.

Quantitative assessment of viable Cryptosporidium parvum load in commercial oysters (Crassostrea virginica) in the Chesapeake Bay.

Science.gov (United States)

Graczyk, Thaddeus K; Lewis, Earl J; Glass, Gregory; Dasilva, Alexandre J; Tamang, Leena; Girouard, Autumn S; Curriero, Frank C

2007-01-01

The epidemiological importance of increasing reports worldwide on Cryptosporidium contamination of oysters remains unknown in relation to foodborne cryptosporidiosis. Thirty market-size oysters (Crassostrea virginica), collected from each of 53 commercial harvesting sites in Chesapeake Bay, MD, were quantitatively tested in groups of six for Cryptosporidium sp. oocysts by immunofluorescent antibody (IFA). After IFA analysis, the samples were retrospectively retested for viable Cryptosporidium parvum oocysts by combined fluorescent in situ hybridization (FISH) and IFA. The mean cumulative numbers of Cryptosporidium sp. oocysts in six oysters (overall, 42.1+/-4.1) were significantly higher than in the numbers of viable C. parvum oocysts (overall, 28.0+/-2.9). Of 265 oyster groups, 221 (83.4%) contained viable C. parvum oocysts, and overall, from 10-32% (mean, 23%) of the total viable oocysts were identified in the hemolymph as distinct from gill washings. The amount of viable C. parvum oocysts was not related to oyster size or to the level of fecal coliforms at the sampling site. This study demonstrated that, although oysters are frequently contaminated with oocysts, the levels of viable oocysts may be too low to cause infection in healthy individuals. FISH assay for identification can be retrospectively applied to properly stored samples.

Investigating antibiotic resistance in non-clinical environments

Directory of Open Access Journals (Sweden)

Fiona eWalsh

2013-02-01

Full Text Available There have been many calls for more information about the natural resistome and these have also highlighted the importance of understanding the soil resistome in the preservation of antibiotics for the treatment of infections. However, to date there have been few studies which have investigated the culturable soil resistome, which highlights the difficulties faced by microbiologists in designing these experiments to produce meaningful data. The World Health Organization definition of resistance is the most fitting to non-clinical environmental studies: Antimicrobial resistance is resistance of a microorganism to an antimicrobial medicine to which it was previously sensitive. The ideal investigation of non-clinical environments for antibiotic resistance of clinical relevance would be using standardized guidelines and breakpoints. This review outlines different definitions and methodologies used to understand antibiotic resistance and suggests how this can be performed outside of the clinical environment.

Impact of anthropogenic activities on the dissemination of antibiotic resistance across ecological boundaries.

Science.gov (United States)

Tripathi, Vijay; Cytryn, Eddie

2017-02-28

Antibiotics are considered to be one of the major medical breakthroughs in history. Nonetheless, over the past four decades, antibiotic resistance has reached alarming levels worldwide and this trend is expected to continue to increase, leading some experts to forecast the coming of a 'post-antibiotic' era. Although antibiotic resistance in pathogens is traditionally linked to clinical environments, there is a rising concern that the global propagation of antibiotic resistance is also associated with environmental reservoirs that are linked to anthropogenic activities such as animal husbandry, agronomic practices and wastewater treatment. It is hypothesized that the emergence and dissemination of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) within and between environmental microbial communities can ultimately contribute to the acquisition of antibiotic resistance in human pathogens. Nonetheless, the scope of this phenomenon is not clear due to the complexity of microbial communities in the environment and methodological constraints that limit comprehensive in situ evaluation of microbial genomes. This review summarizes the current state of knowledge regarding antibiotic resistance in non-clinical environments, specifically focusing on the dissemination of antibiotic resistance across ecological boundaries and the contribution of this phenomenon to global antibiotic resistance. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Resistance of CFRP structures to environmental degradation in low Earth orbit

Science.gov (United States)

Suliga, Agnieszka

Within this study, a development of a protection strategy for ultra-thin CFRP structures from degrading effects of low Earth orbit (LEO) is presented. The proposed strategy involves an application of a modified epoxy resin system on outer layers of the structure, which is cycloaliphatic in its chemical character and reinforced with POSS nanoparticles. The core of the CFRP structure is manufactured using a highly aromatic epoxy resin system which provides excellent mechanical properties, however, its long-term ageing performance in space is not satisfactory, and hence a surface treatment is required to improve its longevity. The developed resin system presented in this thesis is a hybrid material, designed in such a way that its individual constituents each contribute to combating the detrimental effects of radiation, atomic oxygen (AO), temperature extremes and vacuum induced outgassing of exposed material surfaces while operating in LEO. The cycloaliphatic nature of the outer epoxy increases UV resistance and the embedded silicon nanoparticles improve AO and thermal stability. During the study, a material characterization of the developed cycloaliphatic epoxy resins was performed including the effects of nanoparticles on morphology, curing behaviour, thermal-mechanical properties and surface chemistry. Following on that, the efficacy of the modified resin system on space-like resistance was studied. It was found that when the ultra-thin CFRP structures are covered with the developed resin system, their AO resistance is approximately doubled, UV susceptibility decreased by 80% and thermal stability improved by 20%. Following on the successful launch of the InflateSail mission earlier this year, which demonstrated a sail deployment and a controlled de-orbiting, the findings of this study are of importance for the future generation of similar, but significantly longer missions. Ensuring resistance of CFRP structures in a highly corrosive LEO environment is a critical

Selenocysteine modulates resistance to environmental stress and confers anti-aging effects in C. elegans.

Science.gov (United States)

Kim, Jun-Sung; Kim, So-Hyeon; Park, Sang-Kyu

2017-08-01

The free radical theory of aging suggests that cellular oxidative damage caused by free radicals is a leading cause of aging. In the present study, we examined the effects of a well-known anti-oxidant amino acid derivative, selenocysteine, in response to environmental stress and aging using Caenorhabditis elegans as a model system. The response to oxidative stress induced by H2O2 or ultraviolet irradiation was compared between the untreated control and selenocysteine-treated groups. The effect of selenocysteine on lifespan and fertility was then determined. To examine the effect of selenocysteine on muscle aging, we monitored the change in motility with aging in both the untreated control and selenocysteine-treated groups. Dietary supplementation with selenocysteine significantly increased resistance to oxidative stress. Survival after ultraviolet irradiation was also increased by supplementation with selenocysteine. Treatment with selenocysteine confers a longevity phenotype without an accompanying reduction in fertility, which is frequently observed in lifespan-extending interventions as a trade-off in C. elegans. In addition, the age-related decline in motility was significantly delayed by supplementation of selenocysteine. These findings suggest that dietary supplementation of selenocysteine can modulate response to stressors and lead to lifespan extension, thus supporting the free radical theory of aging.

Perspectives on transgenic, herbicide-resistant crops in the United States almost 20 years after introduction.

Science.gov (United States)

Duke, Stephen O

2015-05-01

Herbicide-resistant crops have had a profound impact on weed management. Most of the impact has been by glyphosate-resistant maize, cotton, soybean and canola. Significant economic savings, yield increases and more efficacious and simplified weed management have resulted in widespread adoption of the technology. Initially, glyphosate-resistant crops enabled significantly reduced tillage and reduced the environmental impact of weed management. Continuous use of glyphosate with glyphosate-resistant crops over broad areas facilitated the evolution of glyphosate-resistant weeds, which have resulted in increases in the use of tillage and other herbicides with glyphosate, reducing some of the initial environmental benefits of glyphosate-resistant crops. Transgenic crops with resistance to auxinic herbicides, as well as to herbicides that inhibit acetolactate synthase, acetyl-CoA carboxylase and hydroxyphenylpyruvate dioxygenase, stacked with glyphosate and/or glufosinate resistance, will become available in the next few years. These technologies will provide additional weed management options for farmers, but will not have all of the positive effects (reduced cost, simplified weed management, lowered environmental impact and reduced tillage) that glyphosate-resistant crops had initially. In the more distant future, other herbicide-resistant crops (including non-transgenic ones), herbicides with new modes of action and technologies that are currently in their infancy (e.g. bioherbicides, sprayable herbicidal RNAi and/or robotic weeding) may affect the role of transgenic, herbicide-resistant crops in weed management. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Antibiotic Resistance Characterization of Environmental E. coli Isolated from River Mula-Mutha, Pune District, India.

Science.gov (United States)

Dhawde, Rutuja; Macaden, Ragini; Saranath, Dhananjaya; Nilgiriwala, Kayzad; Ghadge, Appasaheb; Birdi, Tannaz

2018-06-12

In the current study, ceftazidime- and ciprofloxacin-resistant—or dual drug-resistant (DDR)— E. coli were isolated from river Mula-Mutha, which flows through rural Pune district and Pune city. The DDR E. coli were further examined for antibiotic resistance to six additional antibiotics. The study also included detection of genes responsible for ceftazidime and ciprofloxacin resistance and vectors for horizontal gene transfer. Twenty-eight percent of the identified DDR E. coli were resistant to more than six antibiotics, with 12% being resistant to all eight antibiotics tested. Quinolone resistance was determined through the detection of qnrA , qnrB , qnrS and oqxA genes, whereas cephalosporin resistance was confirmed through detection of TEM, CTX-M-15, CTX-M-27 and SHV genes. Out of 219 DDR E. coli , 8.2% were qnrS positive and 0.4% were qnrB positive. Percentage of isolates positive for the TEM, CTX-M-15 and CTX-M-27 genes were 32%, 46% and 0.9%, respectively. None of the DDR E. coli tested carried the qnrA , SHV and oqxA genes. Percentage of DDR E. coli carrying Class 1 and 2 integrons (mobile genetic elements) were 47% and 8%, respectively. The results showed that antibiotic resistance genes (ARGs) and integrons were present in the E. coli isolated from the river at points adjoining and downstream of Pune city.

Antimicrobial resistance in Danish pigs: A cross sectional study of the association between antimicrobial resistance and geography, exposure to antimicrobials, and trade

DEFF Research Database (Denmark)

Birkegård, Anna Camilla

Antimicrobial resistance is a worldwide problem of paramount importance for both humans and animals. To combat the emergence of antimicrobial resistance, the problem must be targeted in all major reservoirs as it is assumed that a high level of AMR genes in environmental reservoirs can increase...... the risk of human pathogens becoming resistant. Pigs might constitute an important reservoir. Therefore, it is important to manage antimicrobial resistance in pigs. Before effectiveactions can be initiated, it is crucial to know which factors are associated with the levels of antimicrobial resistance...... the collection of information on relevant factors. The aim of this PhD project was to study the relationship between the levels of antimicrobial resistance genes and three factors in Danish pig farms: the geographical location of the farm, the exposure to antimicrobials, and the trade patterns. Data collection...

The destruction of parasitic resistant stages in sewage sludge by irradiation with low accelerating voltage electrons

International Nuclear Information System (INIS)

Enigk, K.; Holl, P.; Dey-Hazra, A.; Polymer-Physik G.m.b.H. und Co. K.G., Tuebingen

1975-01-01

The destroying effect of ionizing radiation on parasitic resistant stages in sludge has been tested. Suitable for that process is an electron beam accelerator which will be provided with energy from the electric power supply network which can be switched on and off according to the requirements. Such modern utilities have an enormous beam capacity and a high operating safety. The process is working according to the continuous flow principle and at room temperature. In a series of 13 experiments the effect of different doses has been tested. A dose of 480 kRad (accelerating voltage: 400 kV, beam current: 10 mA , irradiation time: 24 sec.) can easily obtained in practical work and is economically acceptable. By these means approximately 97% of the following parasitic stages have been destroyed: undeveloped eggs of Ascaris suum, Trichuris suis, Fasciola hepatica and gastrointestinal strongylids of pigs, embryonated eggs of Capillaria obsignata and probably of Taenia spec. A few third-stage larvae of Oesophagostomum (Strongylidae) of pigs survived even 108 sec of irradiation; however, they did not develop to maturity in the definitive host. Approximately 25% of the sporulated oocysts of Eimeria tenella were still infective after 108 sec of irradiation. (orig.) [de

Modeling effective transmission pathways and control of the world's most successful parasite.

Science.gov (United States)

Turner, Matthew; Lenhart, Suzanne; Rosenthal, Benjamin; Zhao, Xiaopeng

2013-06-01

Toxoplasma gondii(T. gondii) is a single-celled, intracellular protozoan responsible for the disease toxoplasmosis. The parasite is prevalent worldwide, and it infects all warm-blooded vertebrates. Consumption of meats in which this parasite has encysted confers risk of infection to people and other animals, as does ingestion of water or foods contaminated with environmentally resistant oocysts excreted by cats. Vertical transmission (from mother to offspring) is also possible, leading to disease risk and contributing additional means of ensuring perpetuation of transmission. In this work, we adopt a differential equation model to investigate the effective transmission pathways of T. gondii, as well as potential control mechanisms. Detailed analyses are carried out to examine the significance of transmission routes, virulence, vertical transmission, parasite-induced changes in host behavior, and controls based on vaccination and harvesting. Modeling and analysis efforts may shed insights into understanding the complex life cycle of T. gondii. Copyright © 2013 Elsevier Inc. All rights reserved.

Effect of Microstructure and Environment on Static Crack Growth Resistance in Alloy 706

Science.gov (United States)

Yang, Ling; Hawk, Jeffrey A.; Duquette, David J.; Schwant, Robin C.

2009-06-01

The relationship between thermo-mechanical processing, resultant microstructure, and mechanical properties has been of interest in the field of metallurgy for centuries. In this work, the effect of heat treatment on microstructure and key mechanical properties important for turbine rotor design has been investigated. Specifically, the tensile yield strength and crack growth resistance for a nickel-iron based superalloy 706 has been examined. Through a systematic study, a correlation was found between the processing parameters and the microstructure. Specifically, differences in grain boundary and grain interior precipitates were identified and correlated with processing conditions. Further, a strong relationship between microstructure and mechanical properties was identified. The type and orientation of grain boundary precipitates affect time-dependent crack propagation resistance, and the size and volume fraction of grain interior precipitates were correlated with tensile yield strength. It was also found that there is a strong environmental effect on time-dependent crack propagation resistance, and the sensitivity to environmental damage is microstructure dependent. Microstructures with η decorated grain boundaries were more resistant to environmental damage through oxygen embrittlement than microstructures with no η phase on the grain boundaries. An effort was made to explore the mechanisms of improving the time-dependent crack propagation resistance through thermo-mechanical processing, and several mechanisms were identified in both the environment-dependent and the environment-independent category. These mechanisms were ranked based on their contributions to crack propagation resistance.

Irrigation waters and pipe-based biofilms as sources for antibiotic-resistant bacteria

Science.gov (United States)

The presence of antibiotic-resistant bacteria in environmental surface waters has gained recent attention. Wastewater- and drinking water distribution systems are known to disseminate antibiotic-resistant bacteria, with the biofilms that form on the inner-surfaces of the pipeline as a hotspot for pr...

Characterization of fluoroquinolone resistance and qnr diversity in Enterobacteriaceae from municipal biosolids.

Directory of Open Access Journals (Sweden)

Ella eKaplan

2013-06-01

Full Text Available Municipal biosolids produced during activated sludge treatment applied in waste water treatment plants, are significant reservoirs of antibiotic resistance, since they assemble both natural and fecal microbiota, as well as residual concentrations of antibiotic compounds. This raises major concerns regarding the environmental and epidemiological consequences of using them as fertilizers for crops. The second generation fluoroquinolone ciprofloxacin is probably the most abundant antibiotic compound detected in municipal biosolids due to its widespread use and sorption properties. Although fluoroquinolone resistance was originally thought to result from mutations in bacterial gyrase and topoisomerase IV genes, it is becoming apparent that it is also attributed to plasmid-associated resistance factors, which may propagate environmental antibiotic resistance. The objective of this study was to assess the impact of the activated sludge process on fluoroquinolone resistance. The scope of resistances and mobile genetic mechanisms associated with fluoroquinolone resistance were evaluated by screening large collections of ciprofloxacin-resistant Enterobacteriaceae strains from sludge (n=112 and from raw sewage (n=89. Plasmid-mediated quinolone resistance determinants (qnrA, B and S were readily detected in isolates from both environments, the most dominant being qnrS. Interestingly, all qnr variants were significantly more abundant in sludge isolates than in the isolates from raw sewage. Almost all of ciprofloxacin-resistant isolates were resistant to multiple antibiotic compounds. The sludge isolates were on the whole resistant to a broader range of antibiotic compounds than the raw sewage isolates; however this difference was not statistically significant. Collectively, this study indicates that the activated sludge selects for multiresistant bacterial strains, and that mobile quinolone-resistance elements may have a selective advantage in the activated

Sulfonamide-resistant bacteria and their resistance genes in soils fertilized with manures from Jiangsu Province, Southeastern China.

Science.gov (United States)

Wang, Na; Yang, Xiaohong; Jiao, Shaojun; Zhang, Jun; Ye, Boping; Gao, Shixiang

2014-01-01

Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs) increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (psulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China.

[Collective health, territorial and environmental conflicts: bases for a critical socio-environmental approach].

Science.gov (United States)

Porto, Marcelo Firpo de Souza; da Rocha, Diogo Ferreira; Finamore, Renan

2014-10-01

The phenomenon of globalization and the increase in neo-extractivism in the global periphery intensify the search for new territories and natural resources for the economy, resulting in significant impacts on ecosystems and on the lives of vulnerable populations. It is considered that the environmental crisis imposes new challenges and requires an updating of the theoretical and methodological foundations of collective health and the social determinants of health. The scope of this paper is to present theoretical contributions to the construction of a critical socio-environmental approach from a review of the literature structured around previous work on the mapping of environmental conflicts, and conducting empirical studies in conflicting areas. The contributions of sociology, political ecology, postcolonial studies and geography is summarized for the discussion of the socio-environmental determinants of health, as well as experiences that integrate emancipatory knowledge, political subjects, resistances and alternatives for society.

Current scenario of antibiotic resistance and latest strategies to overcome it

Directory of Open Access Journals (Sweden)

Mohankumar J Megha

2014-09-01

Full Text Available Antibiotic resistance in microorganisms has become a critical health issue these days and has evolved to become a worldwide health threat. Over a decade, the resistance level of bacteria has increased many folds due to various factors, accounting to the added pressure on the environmental resistome. Infections that are resistant to these antibiotics show potentially devastating effects on public health, often affecting developing countries. This review focuses on the present scenario of antibiotic resistance and enlists some of the strategies to combat this global community threat.

The antimicrobial resistance crisis: management through gene monitoring

Science.gov (United States)

2016-01-01

Antimicrobial resistance (AMR) is an acknowledged crisis for humanity. Its genetic origins and dire potential outcomes are increasingly well understood. However, diagnostic techniques for monitoring the crisis are currently largely limited to enumerating the increasing incidence of resistant pathogens. Being the end-stage of the evolutionary process that produces antimicrobial resistant pathogens, these measurements, while diagnostic, are not prognostic, and so are not optimal in managing this crisis. A better test is required. Here, using insights from an understanding of evolutionary processes ruling the changing abundance of genes under selective pressure, we suggest a predictive framework for the AMR crisis. We then discuss the likely progression of resistance for both existing and prospective antimicrobial therapies. Finally, we suggest that by the environmental monitoring of resistance gene frequency, resistance may be detected and tracked presumptively, and how this tool may be used to guide decision-making in the local and global use of antimicrobials. PMID:27831476

Dicty_cDB: SLJ419 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available |CB367289.1 E38 early-oocyst library Plasmodium berghei/Anopheles stephensi mixe...7 |CB367287.1 E830 early-oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clone ...oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clon...ly-oocyst library Plasmodium berghei/Anopheles stephensi mixed EST library cDNA clone E3015 similar to Plasm

ANTIBIOTIC RESISTANCE IN THE OPPORTUNISTIC PATHOGEN STENOTROPHOMONAS MALTOPHILIA

Directory of Open Access Journals (Sweden)

María Blanca Sánchez

2015-06-01

Full Text Available Stenotrophomonas maltophilia is an environmental bacterium found in the soil, associated with plants and animals, and in aquatic environments. It is also an opportunistic pathogen now causing an increasing number of nosocomial infections. The treatment of S. maltophilia is quite difficult given its intrinsic resistance to a number of antibiotics, and because it is able to acquire new resistances via horizontal gene transfer and mutations. Certainly, strains resistant to quinolones, cotrimoxale and/or cephalosporins - antibiotics commonly used to treat S. maltophilia infections - have emerged. The increasing number of available S. maltophilia genomes has allowed the identification and annotation of a large number of antimicrobial and heavy metal resistance genes. Most encode inactivating enzymes and efflux pumps, but information on their role in intrinsic and acquired resistance is limited. Non-typical antibiotic resistance mechanisms that also form part of the intrinsic resistome have been identified via mutant library screening. These include non-typical antibiotic resistance genes, such as bacterial metabolism genes, and non-inheritable resistant phenotypes, such as biofilm formation and persistence. Their relationships with resistance are complex and require further study.

Tracking Change: A Look at the Ecological Footprint of Antibiotics and Antimicrobial Resistance

Directory of Open Access Journals (Sweden)

David M. Patrick

2013-03-01

Full Text Available Among the class of pollutants considered as ‘emerging contaminants’, antibiotic compounds including drugs used in medical therapy, biocides and disinfectants merit special consideration because their bioactivity in the environment is the result of their functional design. Antibiotics can alter the structure and function of microbial communities in the receiving environment and facilitate the development and spread of resistance in critical species of bacteria including pathogens. Methanogenesis, nitrogen transformation and sulphate reduction are among the key ecosystem processes performed by bacteria in nature that can also be affected by the impacts of environmental contamination by antibiotics. Together, the effects of the development of resistance in bacteria involved in maintaining overall ecosystem health and the development of resistance in human, animal and fish pathogens, make serious contributions to the risks associated with environmental pollution by antibiotics. In this brief review, we discuss the multiple impacts on human and ecosystem health of environmental contamination by antibiotic compounds.

Self-discharge analysis and characterization of supercapacitors for environmentally powered wireless sensor network applications

Science.gov (United States)

Yang, Hengzhao; Zhang, Ying

2011-10-01

A new approach is presented to characterize the variable leakage resistance, a parameter in the variable leakage resistance model we developed to model supercapacitors used in environmentally powered wireless sensor network applications. Based on an analysis of the supercapacitor terminal behavior during the self-discharge, the variable leakage resistance is modeled as a function of the supercapacitor terminal voltage instead of the self-discharge time, which is more practical for an environmentally powered wireless sensor node. The new characterization approach is implemented and validated using MATLAB Simulink with a 10 F supercapacitor as an example. In addition, effects of initial voltages and temperatures on the supercapacitor self-discharge rate and the variable leakage resistance value are explored.

Plastic responses to four environmental stresses and cross-resistance in a laboratory population of Drosophila melanogaster

DEFF Research Database (Denmark)

Bubliy, Oleg A; Kristensen, Torsten Nygård; Kellermann, Vanessa

2012-01-01

such as reduction of metabolic rate and accumulation of energy reserves might be involved. 6. The lack of cross-resistance induced by acclimation ⁄ hardening treatments suggests that in an environment with multiple stresses, evolution of shared protective systems associated with plastic responses may be constrained.......1. Acclimation or hardening to one stress in arthropods can lead to a plastic response, which confers increased resistance to other stresses. Such cross-resistance may indicate shared physiological resistance mechanisms and a possibility of joint evolution for resistance traits. 2. In this study...

Current perspectives on the dynamics of antibiotic resistance in different reservoirs.

Science.gov (United States)

Caniça, Manuela; Manageiro, Vera; Jones-Dias, Daniela; Clemente, Lurdes; Gomes-Neves, Eduarda; Poeta, Patrícia; Dias, Elsa; Ferreira, Eugénia

2015-09-01

Antibiotic resistance consists of a dynamic web. In this review, we describe the path by which different antibiotic residues and antibiotic resistance genes disseminate among relevant reservoirs (human, animal, and environmental settings), evaluating how these events contribute to the current scenario of antibiotic resistance. The relationship between the spread of resistance and the contribution of different genetic elements and events is revisited, exploring examples of the processes by which successful mobile resistance genes spread across different niches. The importance of classic and next generation molecular approaches, as well as action plans and policies which might aid in the fight against antibiotic resistance, are also reviewed. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Quantitative trait loci (QTL) mapping of resistance to strongyles and coccidia in the free-living Soay sheep (Ovis aries).

Science.gov (United States)

Beraldi, Dario; McRae, Allan F; Gratten, Jacob; Pilkington, Jill G; Slate, Jon; Visscher, Peter M; Pemberton, Josephine M

2007-01-01

A genome-wide scan was performed to detect quantitative trait loci (QTL) for resistance to gastrointestinal parasites and ectoparasitic keds segregating in the free-living Soay sheep population on St. Kilda (UK). The mapping panel consisted of a single pedigree of 882 individuals of which 588 were genotyped. The Soay linkage map used for the scans comprised 251 markers covering the whole genome at average spacing of 15cM. The traits here investigated were the strongyle faecal egg count (FEC), the coccidia faecal oocyst count (FOC) and a count of keds (Melophagus ovinus). QTL mapping was performed by means of variance component analysis so that the genetic parameters of the study traits were also estimated and compared with previous studies in Soay and domestic sheep. Strongyle FEC and coccidia FOC showed moderate heritability (h(2)=0.26 and 0.22, respectively) in lambs but low heritability in adults (h(2)<0.10). Ked count appeared to have very low h(2) in both lambs and adults. Genome scans were performed for the traits with moderate heritability and two genomic regions reached the level of suggestive linkage for coccidia FOC in lambs (logarithm of the odds=2.68 and 2.21 on chromosomes 3 and X, respectively). We believe this is the first study to report a QTL search for parasite resistance in a free-living animal population and therefore may represent a useful reference for similar studies aimed at understanding the genetics of host-parasite co-evolution in the wild.

Detection Antibiotic Resistance of Enviromental Bacterial Strains

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Huda Zuheir Majeed

2018-05-01

Full Text Available      Antibiotics are randomly prescribed  for veterinary and human medication. Antibiotics by little number are used by human , animals are digested uncompletely  in their digestive system and ended up in communal sewage and hospitals, eventually discharge in environmental water sources directly with no processing.     Water itself consider as major factor of dispersal of bacteria between different environmental components. Besides, bacteria had  transferable genetic mobile elements to different sites of soil, water and humans.       Environmental swabs were collected locally including 50 swabs of hospital environment , 15 samples of poultry feces and chicken guts , 20 sample of heavy water and 15 sample of fish tank to identify16 isolate of Staphylococcus (4 isolate of Staphylococus aureus and 12 isolate of coagulase –ve Staphylococcus , 19 isolate of Enterococcus spp. , 7 isolates of Pseudomonas and 5 environment isolates for each Shigella spp.  and Salmonella spp. .           Teicoplanin and Vancomycin sensitivity test of isolates was done , showing that 2out of 16 isolates of Staphylococcus (12.5% were Vancomycin-resistant , and 3out of 19 isolates of Enterococcus (15.7 % were Vancomycin-resistant, while the rest of isolates were Vancomycin- sensitive. From other side , all isolates was Teicoplanin- sensitive except only 1 Enterococcus spp. Isolate which was intermediate . The range of the Vancomycin MIC were (6-64 µg/ml . Vancomycin resistant isolates , showed that some isolates have one plasmid band after Extraction of their DNA.

Environmental/Climatic Effect on Stand-Alone Solar Energy Supply ...

African Journals Online (AJOL)

This paper investigates the climatic eects and environmental variations on the performance of a stand-alone photovoltaic system. The eects of partial shading with dierent climate conditions and load resistance variations were examined. A survey of some of the work done in this eld of environmental eect on solar panel was ...

Impacts of biochar on the environmental risk of antibiotic resistance genes and mobile genetic elements during anaerobic digestion of cattle farm wastewater.

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Sun, Wei; Gu, Jie; Wang, Xiaojuan; Qian, Xun; Tuo, Xiaxia

2018-05-01

Biochar has positive effects on nitrogen conservation during anaerobic digestion, but its impacts on antibiotic resistance genes (ARGs) are unclear. Therefore, the effect of biochar (0, 5, 20, and 50 g/L) on the environmental risk of ARGs during cattle manure wastewater anaerobic digestion were investigated. The results showed that 5 g/L biochar reduced the relative abundances (RAs) of 5/13 ARGs while 20 g/L biochar significantly reduced the total RAs of ARGs in the digestion products, where the RA of ISCR1 was 0.89 log lower than the control. Biochar mainly affected the distribution of ARGs by influencing the RAs of Firmicutes and Proteobacteria, and the influence of 20 g/L biochar was greater than that of 5 g/L. Mobile genetic elements also influenced the ARG profiles, especially intI2 and ISCR1. The addition of 20 g/L biochar to cattle farm wastewater anaerobic digestion systems could reduce the environmental risk of ARGs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Seasonal Variations in Resistivity at a Police Forensic Site and the Effectiveness of Unconventional Array Types

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Edwards, S.; Bank, C. G.

2016-12-01

Geophysical studies involving the detection of buried organic material can be affected by the passage of time and environmental changes such as temperature and, in more importantly, water content in the ground. These effects can be of particular concern for police forensic investigations. This study involved conducting multiple resistivity surveys across 4 months to determine how time and environmental variations affected the detection of porcine carcasses buried four years previous at a provincial police training and research site. Our research also explored survey results of non-conventional grid and square arrays versus traditional linear arrays. The study site is located in Bolton, Ontario, and measures 16 m by 30 m. It contains 18 graves plus other buried objects. Studies were conducted approximately every other week. The resistivity lines used Wenner arrays of 24 m (0.5 m electrode spacing) and 48 m (1 m spacing) in length. Environmental data was obtained from Environment Canada and through simple observations. Preliminary findings indicated that time and environmental changes affected the detection of the porcine bodies by either being too dry and having too high a resistivity to survey effectively, or too wet and having the site flushed with water making the surrounding ground similar in resistivity to the bodies. Future research is needed to further explore how best to minimize environmental changes from resistivity results to enable reliable detection of buried organic material such as human remains In regard to array configurations, the square array in particular shows promise in that it can be set up and executed in less time than running several linear arrays over the same area. The application of such unconventional arrays to police forensic work may prove valuable if the area of interest is off-limits for resistivity surveys due to physical obstructions.

Deep sequence analysis reveals the ovine rumen as a reservoir of antibiotic resistance genes.

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Hitch, Thomas C A; Thomas, Ben J; Friedersdorff, Jessica C A; Ougham, Helen; Creevey, Christopher J

2018-04-01

Antibiotic resistance is an increasingly important environmental pollutant with direct consequences for human health. Identification of environmental sources of antibiotic resistance genes (ARGs) makes it possible to follow their evolution and prevent their entry into the clinical setting. ARGs have been found in environmental sources exogenous to the original source and previous studies have shown that these genes are capable of being transferred from livestock to humans. Due to the nature of farming and the slaughter of ruminants for food, humans interact with these animals in close proximity, and for this reason it is important to consider the risks to human health. In this study, we characterised the ARG populations in the ovine rumen, termed the resistome. This was done using the Comprehensive Antibiotic Resistance Database (CARD) to identify the presence of genes conferring resistance to antibiotics within the rumen. Genes were successfully mapped to those that confer resistance to a total of 30 different antibiotics. Daptomycin was identified as the most common antibiotic for which resistance is present, suggesting that ruminants may be a source of daptomycin ARGs. Colistin resistance, conferred by the gene pmrE, was also found to be present within all samples, with an average abundance of 800 counts. Due to the high abundance of some ARGs (against daptomycin) and the presence of rare ARGs (against colistin), we suggest further study and monitoring of the rumen resistome as a possible source of clinically relevant ARGs. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Molecular characterization of antibiotic resistance in enterococci recovered from seagulls (Larus cachinnans) representing an environmental health problem.

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Radhouani, Hajer; Igrejas, Gilberto; Pinto, Luís; Gonçalves, Alexandre; Coelho, Céline; Rodrigues, Jorge; Poeta, Patrícia

2011-08-01

Antimicrobial resistance and the mechanisms implicated were studied in 54 enterococci recovered from 57 seagull fecal samples. Almost 78% of the recovered enterococci showed resistance against one or more antibiotics and these isolates were identified to the species level. E. faecium was the most prevalent species (52.4%). High percentages of erythromycin and tetracycline resistances were found among our isolates (95.2%), and lower percentages were identified to other antibiotics. Most of the tetracycline-resistant strains carried the tet(M) and/or tet(L) genes. Genes associated with Tn916/Tn1545 and/or Tn5397 transposons were detected in 45% of tetracycline-resistant isolates. The erm(B) gene was detected in 65% of erythromycin-resistant isolates. The vat(D) and vat(E) genes were present in 5.9% and 11.8% of quinupristin/dalfopristin-resistant isolates, respectively. The ant(6)-Ia gene was identified in 57.1% of streptomycin-resistant isolates. All nine kanamycin-resistant isolates carried the aph(3)'-IIIa gene. The cat(A) gene was found in two chloramphenicol-resistant isolates. Seagulls should be considered a risk species for spreading in the environment antimicrobial resistant enterococci and can serve as a sentinel for antibiotic pressure from the surrounding farm and urban setting.

Bacteria-Mineral Interactions on the Surfaces of Metal-Resistant Bacteria

International Nuclear Information System (INIS)

Malkin, A.J.

2010-01-01

The extraordinary ability of indigenous microorganisms, like metal-resistant bacteria, for biotransformation of toxic compounds is of considerable interest for the emerging area of environmental bioremediation. However, the underlying mechanisms by which metal-resistant bacteria transform toxic compounds are currently unknown and await elucidation. The project's objective was to study stress-induced responses of metal-resistant bacteria to environmental changes and chemical stimulants. This project involved a multi-institutional collaboration of our LLNL group with the group of Dr. H.-Y. Holman (Lawrence Berkeley National Laboratory). In this project, we have utilized metal-resistant bacteria Arthrobacter oxydans as a model bacterial system. We have utilized atomic force microscopy (AFM) to visualize for the first time at the nanometer scale formation of stress-induced structures on bacterial surfaces in response to Cr (VI) exposure. We have demonstrated that structure, assembly, and composition of these stress-induced structures are dependent on Cr (VI) concentrations. Our AFM observations of the appearance and development of stress-induced layers on the surfaces of Arthrobacter oxydans bacteria exposed to Cr (VI) were confirmed by Dr. Holman's biochemical, electron microscopy, and synchrotron infrared spectromicroscopy studies. In general, in vitro imaging of live microbial and cellular systems represents one of the most challenging issues in application of AFM. Various approaches for immobilization of bacteria on the substrate for in vitro imaging were tested in this project. Imaging of live bacteria was achieved, however further optimization of experimental methods are needed for high-resolution visualization of the cellular environmental structural dynamics by AFM. This project enhanced the current insight into molecular architecture, structural and environmental variability of bacterial systems. The project partially funded research for two book chapters (1

A rapid seedling resistance assay identifies wild tomato lines that are resistant to Psuedomonas syringe pv. tomato race 1

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Bacterial speck caused by Pseudomonas syringae has historically been controlled by the Pto/Prf gene cluster. Emerging strains like P. syringae pv. tomato race 1 overcome resistance conferred by Pto/Prf, and can cause serious crop loss under appropriate environmental conditions. We developed a rapid ...

Antibiotic resistant bacteria in urban sewage: Role of full-scale wastewater treatment plants on environmental spreading.

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Turolla, A; Cattaneo, M; Marazzi, F; Mezzanotte, V; Antonelli, M

2018-01-01

The presence of antibiotic resistant bacteria (ARB) in wastewater was investigated and the role of wastewater treatment plants (WWTPs) in promoting or limiting antibiotic resistance was assessed. Escherichia coli (E. coli) and total heterotrophic bacteria (THB) resistance to ampicillin, chloramphenicol and tetracycline was monitored in three WWTPs located in Milan urban area (Italy), differing among them for the operating parameters of biological process, for the disinfection processes (based on sodium hypochlorite, UV radiation, peracetic acid) and for the discharge limits to be met. Wastewater was collected from three sampling points along the treatment sequence (WWTP influent, effluent from sand filtration, WWTP effluent). Antibiotic resistance to ampicillin was observed both for E. coli and for THB. Ampicillin resistant bacteria in the WWTP influents were 20-47% of E. coli and 16-25% of THB counts. A limited resistance to chloramphenicol was observed only for E. coli, while neither for E. coli nor for THB tetracycline resistance was observed. The biological treatment and sand filtration led to a decrease in the maximum percentage of ampicillin-resistant bacteria (20-29% for E. coli, 11-21% for THB). However, the conventionally adopted parameters did not seem adequate to support an interpretation of WWTP role in ARB spread. Peracetic acid was effective in selectively acting on antibiotic resistant THB, unlike UV radiation and sodium hypochlorite. The low counts of E. coli in WWTP final effluents in case of agricultural reuse did not allow to compare the effect of the different disinfection processes on antibiotic resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Genomic Basis of Intrinsic and Acquired Antibiotic Resistance in the Genus Serratia

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Luisa Sandner-Miranda

2018-05-01

Full Text Available Serratia marcescens, a member of the Enterobacteriaceae family, was long thought to be a non-pathogenic bacterium prevalent in environmental habitats. Together with other members of this genus, it has emerged in recent years as an opportunistic nosocomial pathogen causing various types of infections. One important feature of pathogens belonging to this genus is their intrinsic and acquired resistance to a variety of antibiotic families, including β-lactam, aminoglycosides, quinolones and polypeptide antibiotics. The aim of this study was to elucidate which genes participate in the intrinsic and acquired antibiotic resistance of this genus in order to determine the Serratia genus resistome. We performed phylogenomic and comparative genomic analyses using 32 Serratia spp. genomes deposited in the NCBI GenBank from strains isolated from different ecological niches and different lifestyles. S. marcescens strain SmUNAM836, which was previously isolated from a Mexican adult with obstructive pulmonary disease, was included in this study. The results show that most of the antibiotic resistance genes (ARGs were found on the chromosome, and to a lesser degree, on plasmids and transposons acquired through horizontal gene transfer. Four strains contained the gyrA point mutation in codon Ser83 that confers quinolone resistance. Pathogenic and environmental isolates presented a high number of ARGs, especially genes associated with efflux systems. Pathogenic strains, specifically nosocomial strains, presented more acquired resistance genes than environmental isolates. We may conclude that the environment provides a natural reservoir for antibiotic resistance, which has been underestimated in the medical field.

The Genomic Basis of Intrinsic and Acquired Antibiotic Resistance in the Genus Serratia

Science.gov (United States)

Sandner-Miranda, Luisa; Vinuesa, Pablo; Cravioto, Alejandro; Morales-Espinosa, Rosario

2018-01-01

Serratia marcescens, a member of the Enterobacteriaceae family, was long thought to be a non-pathogenic bacterium prevalent in environmental habitats. Together with other members of this genus, it has emerged in recent years as an opportunistic nosocomial pathogen causing various types of infections. One important feature of pathogens belonging to this genus is their intrinsic and acquired resistance to a variety of antibiotic families, including β-lactam, aminoglycosides, quinolones and polypeptide antibiotics. The aim of this study was to elucidate which genes participate in the intrinsic and acquired antibiotic resistance of this genus in order to determine the Serratia genus resistome. We performed phylogenomic and comparative genomic analyses using 32 Serratia spp. genomes deposited in the NCBI GenBank from strains isolated from different ecological niches and different lifestyles. S. marcescens strain SmUNAM836, which was previously isolated from a Mexican adult with obstructive pulmonary disease, was included in this study. The results show that most of the antibiotic resistance genes (ARGs) were found on the chromosome, and to a lesser degree, on plasmids and transposons acquired through horizontal gene transfer. Four strains contained the gyrA point mutation in codon Ser83 that confers quinolone resistance. Pathogenic and environmental isolates presented a high number of ARGs, especially genes associated with efflux systems. Pathogenic strains, specifically nosocomial strains, presented more acquired resistance genes than environmental isolates. We may conclude that the environment provides a natural reservoir for antibiotic resistance, which has been underestimated in the medical field.

Resilience to stress and disturbance, and resistance to Bromus tectorum L. invasion in cold desert shrublands of western North America

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Chambers, Jeanne C.; Bradley, Bethany A.; Brown, Cynthia S.; D'Antonio, Carla; Germino, Matthew J.; Grace, James B.; Hardegree, Stuart P.; Miller, Richard F.; Pyke, David A.

2013-01-01

Alien grass invasions in arid and semi-arid ecosystems are resulting in grass–fire cycles and ecosystem-level transformations that severely diminish ecosystem services. Our capacity to address the rapid and complex changes occurring in these ecosystems can be enhanced by developing an understanding of the environmental factors and ecosystem attributes that determine resilience of native ecosystems to stress and disturbance, and resistance to invasion. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked questions about (a) ecosystem attributes that determine resilience and resistance along environmental gradients, (b) effects of disturbances like livestock grazing and altered fire regimes and of stressors like rapid climate change, rising CO2, and N deposition on resilience and resistance, and (c) interacting effects of resilience and resistance on ecosystems with different environmental conditions. We conclude by providing strategies for the use of resilience and resistance concepts in a management context. At ecological site scales, state and transition models are used to illustrate how differences in resilience and resistance influence potential alternative vegetation states, transitions among states, and thresholds. At landscape scales management strategies based on resilience and resistance—protection, prevention, restoration, and monitoring and adaptive management—are used to determine priority management areas and appropriate actions.

Investigating the link between imipenem resistance and biofilm formation by Pseudomonas aeruginosa.

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Musafer, Hadeel K; Kuchma, Sherry L; Naimie, Amanda A; Schwartzman, Joseph D; Al-Mathkhury, Harith J Fahad; O'Toole, George A

2014-07-01

Pseudomonas aeruginosa, a ubiquitous environmental organism, is a difficult-to-treat opportunistic pathogen due to its broad-spectrum antibiotic resistance and its ability to form biofilms. In this study, we investigate the link between resistance to a clinically important antibiotic, imipenem, and biofilm formation. First, we observed that the laboratory strain P. aeruginosa PAO1 carrying a mutation in the oprD gene, which confers resistance to imipenem, showed a modest reduction in biofilm formation. We also observed an inverse relationship between imipenem resistance and biofilm formation for imipenem-resistant strains selected in vitro, as well as for clinical isolates. We identified two clinical isolates of P. aeruginosa from the sputum of cystic fibrosis patients that formed robust biofilms, but were sensitive to imipenem (MIC ≤ 2 μg/ml). To test the hypothesis that there is a general link between imipenem resistance and biofilm formation, we performed transposon mutagenesis of these two clinical strains to identify mutants defective in biofilm formation, and then tested these mutants for imipenem resistance. Analysis of the transposon mutants revealed a role for previously described biofilm factors in these clinical isolates of P. aeruginosa, including mutations in the pilY1, pilX, pilW, algC, and pslI genes, but none of the biofilm-deficient mutants became imipenem resistant (MIC ≥ 8 μg/ml), arguing against a general link between biofilm formation and resistance to imipenem. Thus, assessing biofilm formation capabilities of environmental isolates is unlikely to serve as a good predictor of imipenem resistance. We also discuss our findings in light of the limited literature addressing planktonic antibiotic resistance factors that impact biofilm formation.

Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

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Lázaro Molina

Full Text Available Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267 kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.

Toxoplasma gondii, source to sea: higher contribution of domestic felids to terrestrial parasite loading despite lower infection prevalence.

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Vanwormer, Elizabeth; Conrad, Patricia A; Miller, Melissa A; Melli, Ann C; Carpenter, Tim E; Mazet, Jonna A K

2013-09-01

Environmental transmission of Toxoplasma gondii, a global zoonotic parasite, adversely impacts human and animal health. Toxoplasma is a significant cause of mortality in threatened Southern sea otters, which serve as sentinels for disease threats to people and animals in coastal environments. As wild and domestic felids are the only recognized hosts capable of shedding Toxoplasma oocysts into the environment, otter infection suggests land-to-sea pathogen transmission. To assess relative contributions to terrestrial parasite loading, we evaluated infection and shedding among managed and unmanaged feral domestic cats, mountain lions, and bobcats in coastal California, USA. Infection prevalence differed among sympatric felids, with a significantly lower prevalence for managed feral cats (17%) than mountain lions, bobcats, or unmanaged feral cats subsisting on wild prey (73-81%). A geographic hotspot of infection in felids was identified near Monterey Bay, bordering a high-risk site for otter infection. Increased odds of oocyst shedding were detected in bobcats and unmanaged feral cats. Due to their large populations, pet and feral domestic cats likely contribute more oocysts to lands bordering the sea otter range than native wild felids. Continued coastal development may influence felid numbers and distribution, increase terrestrial pathogens in freshwater runoff, and alter disease dynamics at the human-animal-environment interface.

[Immunotoxicity and environmental substances].

Science.gov (United States)

Teshima, Reiko

2014-01-01

A well functioning immune system is essential in maintaining integrity of the organism, and malfunction may have severe health consequences. Environmental substances may pose direct toxicity to components of the immune system, often leading to immunosuppression and resulting reduced resistance to infections and tumors. Alternatively, such substances may be recognized by the immune system in a specific fashion, which may result in allergy and autoimmunity. A proper risk assessment of environmental substances in terms of immunotoxicity is necessary. In this manuscript, I reviewed recent three topics about immunotoxicity: (1) IPCS/WHO Guidance for immunotoxicity risk assessment for chemicals, (2) Intestinal immunotoxicity, and (3) Epicutaneous sensitization of food proteins.

Metagenomic frameworks for monitoring antibiotic resistance in aquatic environments.

Science.gov (United States)

Port, Jesse A; Cullen, Alison C; Wallace, James C; Smith, Marissa N; Faustman, Elaine M

2014-03-01

High-throughput genomic technologies offer new approaches for environmental health monitoring, including metagenomic surveillance of antibiotic resistance determinants (ARDs). Although natural environments serve as reservoirs for antibiotic resistance genes that can be transferred to pathogenic and human commensal bacteria, monitoring of these determinants has been infrequent and incomplete. Furthermore, surveillance efforts have not been integrated into public health decision making. We used a metagenomic epidemiology-based approach to develop an ARD index that quantifies antibiotic resistance potential, and we analyzed this index for common modal patterns across environmental samples. We also explored how metagenomic data such as this index could be conceptually framed within an early risk management context. We analyzed 25 published data sets from shotgun pyrosequencing projects. The samples consisted of microbial community DNA collected from marine and freshwater environments across a gradient of human impact. We used principal component analysis to identify index patterns across samples. We observed significant differences in the overall index and index subcategory levels when comparing ecosystems more proximal versus distal to human impact. The selection of different sequence similarity thresholds strongly influenced the index measurements. Unique index subcategory modes distinguished the different metagenomes. Broad-scale screening of ARD potential using this index revealed utility for framing environmental health monitoring and surveillance. This approach holds promise as a screening tool for establishing baseline ARD levels that can be used to inform and prioritize decision making regarding management of ARD sources and human exposure routes. Port JA, Cullen AC, Wallace JC, Smith MN, Faustman EM. 2014. Metagenomic frameworks for monitoring antibiotic resistance in aquatic environments. Environ Health Perspect 122:222–228; http://dx.doi.org/10.1289/ehp

Cryptosporidiosis outbreaks associated with recreational water use--five states, 2006.

Science.gov (United States)

2007-07-27

Cryptosporidiosis is a gastrointestinal illness caused by parasitic protozoa of the genus Cryptosporidium and can produce watery diarrhea lasting 1-3 weeks; one or two cases per 100,000 population are reported annually in the United States. Fecal-oral transmission of Cryptosporidium oocysts occurs through ingestion of contaminated drinking or recreational water, consumption of contaminated food, and contact with infected persons or animals (e.g., cattle or sheep). Unlike bacterial pathogens, Cryptosporidium oocysts are resistant to chlorine disinfection and can survive for days in treated recreational water venues (e.g., public and residential swimming pools and community and commercial water parks) despite adherence to recommended residual chlorine levels (1-3 ppm). For 2006, a total of 18 cryptosporidiosis outbreaks have been reported (as of July 24, 2007) to CDC's U.S. Waterborne Disease and Outbreak Surveillance System, compared with five outbreaks reported for 2003 and seven for 2004; data for 2005 and 2006 are not yet final. This report describes five laboratory-confirmed cryptosporidiosis outbreaks in 2006 that involved public recreational water use. The popularity of recreational water venues, the number and geographic distribution of recent cryptosporidiosis outbreaks, and the resistance of Cryptosporidium to chlorination suggest that treatment strategies for recreational water facilities need to be improved.

Elevated Rate of Genome Rearrangements in Radiation-Resistant Bacteria

OpenAIRE

Repar, Jelena; Supek, Fran; Klanjscek, Tin; Warnecke, Tobias; Zahradka, Ksenija; Zahradka, Davor

2017-01-01

A number of bacterial, archaeal, and eukaryotic species are known for their resistance to ionizing radiation. One of the challenges these species face is a potent environmental source of DNA double-strand breaks, potential drivers of genome structure evolution. Efficient and accurate DNA double-strand break repair systems have been demonstrated in several unrelated radiation-resistant species and are putative adaptations to the DNA damaging environment. Such adaptations are expected to compen...

Temporal scale dependent interactions between multiple environmental disturbances in microcosm ecosystems.

Science.gov (United States)

Garnier, Aurélie; Pennekamp, Frank; Lemoine, Mélissa; Petchey, Owen L

2017-12-01

Global environmental change has negative impacts on ecological systems, impacting the stable provision of functions, goods, and services. Whereas effects of individual environmental changes (e.g. temperature change or change in resource availability) are reasonably well understood, we lack information about if and how multiple changes interact. We examined interactions among four types of environmental disturbance (temperature, nutrient ratio, carbon enrichment, and light) in a fully factorial design using a microbial aquatic ecosystem and observed responses of dissolved oxygen saturation at three temporal scales (resistance, resilience, and return time). We tested whether multiple disturbances combine in a dominant, additive, or interactive fashion, and compared the predictability of dissolved oxygen across scales. Carbon enrichment and shading reduced oxygen concentration in the short term (i.e. resistance); although no other effects or interactions were statistically significant, resistance decreased as the number of disturbances increased. In the medium term, only enrichment accelerated recovery, but none of the other effects (including interactions) were significant. In the long term, enrichment and shading lengthened return times, and we found significant two-way synergistic interactions between disturbances. The best performing model (dominant, additive, or interactive) depended on the temporal scale of response. In the short term (i.e. for resistance), the dominance model predicted resistance of dissolved oxygen best, due to a large effect of carbon enrichment, whereas none of the models could predict the medium term (i.e. resilience). The long-term response was best predicted by models including interactions among disturbances. Our results indicate the importance of accounting for the temporal scale of responses when researching the effects of environmental disturbances on ecosystems. © 2017 The Authors. Global Change Biology Published by John Wiley

“Self-Employed” in Caregivinghood: The Contribution of Swedish Informal Caregivers’ Environmental and Contextual Resistance Resources and Deficits

Directory of Open Access Journals (Sweden)

Monica Eriksson

2017-07-01

Full Text Available Informal caregivers provide the majority of care for older adults residing in their own homes. Caregivinghood, a new evidence-based concept, describes a time of life when relatives provide care at home. These caregivers need knowledge regarding resources to help them resolve the challenges they encounter. The theoretical framework underpinning this study is Antonovsky’s salutogenic theory of health. This study had two aims: (1 to examine the salutogenic core concepts Generalized and Specific Resistance Resources and Deficits (GRRs/SRRs and GRDs/SRDs described by Swedish informal caregivers as originating from the environmental and contextual domain of caregivinghood and (2 to discuss how this new knowledge might contribute to the development of health promotion initiatives. This qualitative and theory driven study used inductive and deductive data analysis. Data were gathered through salutogenically guided face-to-face interviews of 32 Swedish informal caregivers. In addition, the study relied on the salutogenic core concepts Specific and Generalized Resistance Resources and Deficits originating from their environment and context. Being in empowering surroundings reflects the presence of usable SRRs/GRRs, whereas Struggling in impeding surroundings reflects the presence of SRDs/GRDs. The results indicate that health-enhancing support has to be individualized (SRRs/SRDs and generalized (GRRs/GRDs. This study’s salutogenic approach and the methodology enhance the understanding of the mechanisms behind the development of Sense of Coherence. The results contribute both empirically and theoretically to strengthen health promotion research and practice when developing activities and support for caregivers in stressful situations, such as informal caregiving.

Vital and dispensable roles of Plasmodium multidrug resistance transporters during blood- and mosquito-stage development.

Science.gov (United States)

Rijpma, Sanna R; van der Velden, Maarten; Annoura, Takeshi; Matz, Joachim M; Kenthirapalan, Sanketha; Kooij, Taco W A; Matuschewski, Kai; van Gemert, Geert-Jan; van de Vegte-Bolmer, Marga; Siebelink-Stoter, Rianne; Graumans, Wouter; Ramesar, Jai; Klop, Onny; Russel, Frans G M; Sauerwein, Robert W; Janse, Chris J; Franke-Fayard, Blandine M; Koenderink, Jan B

2016-07-01

Multidrug resistance (MDR) proteins belong to the B subfamily of the ATP Binding Cassette (ABC) transporters, which export a wide range of compounds including pharmaceuticals. In this study, we used reverse genetics to study the role of all seven Plasmodium MDR proteins during the life cycle of malaria parasites. Four P. berghei genes (encoding MDR1, 4, 6 and 7) were refractory to deletion, indicating a vital role during blood stage multiplication and validating them as potential targets for antimalarial drugs. Mutants lacking expression of MDR2, MDR3 and MDR5 were generated in both P. berghei and P. falciparum, indicating a dispensable role for blood stage development. Whereas P. berghei mutants lacking MDR3 and MDR5 had a reduced blood stage multiplication in vivo, blood stage growth of P. falciparum mutants in vitro was not significantly different. Oocyst maturation and sporozoite formation in Plasmodium mutants lacking MDR2 or MDR5 was reduced. Sporozoites of these P. berghei mutants were capable of infecting mice and life cycle completion, indicating the absence of vital roles during liver stage development. Our results demonstrate vital and dispensable roles of MDR proteins during blood stages and an important function in sporogony for MDR2 and MDR5 in both Plasmodium species. © 2016 John Wiley & Sons Ltd.

Dissemination of antimicrobial resistance in microbial ecosystems through horizontal gene transfer

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Christian Johannes Hendrik Von Wintersdorff

2016-02-01

Full Text Available The emergence and spread of antibiotic resistance among pathogenic bacteria has been a rising problem for public health in recent decades. It is becoming increasingly recognized that not only antibiotic resistance genes (ARGs encountered in clinical pathogens are of relevance, but rather, all pathogenic, commensal as well as environmental bacteria – and also mobile genetic elements and bacteriophages – form a reservoir of ARGs (the resistome from which pathogenic bacteria can acquire resistance via horizontal gene transfer (HGT. HGT has caused antibiotic resistance to spread from commensal and environmental species to pathogenic ones, as has been shown for some clinically important ARGs. Of the three canonical mechanisms of HGT, conjugation is thought to have the greatest influence on the dissemination of ARGs. While transformation and transduction are deemed less important, recent discoveries suggest their role may be larger than previously thought. Understanding the extent of the resistome and how its mobilization to pathogenic bacteria takes place is essential for efforts to control the dissemination of these genes. Here, we will discuss the concept of the resistome, provide examples of HGT of clinically relevant ARGs and present an overview of the current knowledge of the contributions the various HGT mechanisms make to the spread of antibiotic resistance.

Effects of silicon on plant resistance to environmental stresses: review

Science.gov (United States)

Balakhnina, T.; Borkowska, A.

2013-03-01

The role of exogenous silicon in enhancing plant resistance to various abiotic stressors: salinity, drought, metal toxicities and ultraviolet radiation are presented. The data on possible involvement of silicon in reducing the reactive oxygen species generation, intensity of lipid peroxidation, and in some cases, increasing the activity of enzymes of the reactive oxygen species detoxificators: superoxide dismutase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase and catalase are analyzed.

Reasons of chlorella strain's resistance to physical and chemical factors of environment

Energy Technology Data Exchange (ETDEWEB)

Apasheva, L M; Bujiashvilie, D M; Naydich, V I; Shevchenko, V A

1979-07-01

Under environmental pollution it is necessary to study the reasons of an organism's resistance as well as the specificity of it. Some chlorella strains were under the influence of uv- and x-irradiation, heat treatment, cadmium salts, insecticide, and detergent. It was shown that cells which were resistant to physical factors were resistant to chemical intoxication, as well. The positive correlation between resistance of strains and the described influences and the levels of endogenic thiols was found. The second reason for higher resistance is an increase of free radicals' concentration. It is linked with increasing P/sub 700/ quantity of electron-transport chains that make possible higher levels of photosynthetic reactions of resistant cells.

Stalking Antibiotic-Resistant Bacteria in Common Vegetables

Science.gov (United States)

Brock, David; Boeke, Caroline; Josowitz, Rebecca; Loya, Katherine

2004-01-01

The study developed a simple experimental protocol for studying antibiotic resistant bacteria that will allow students to determine the proportion of such bacteria found on common fruit and vegetable crops. This protocol can open up the world of environmental science and show how human behavior can dramatically alter ecosystems.

Cryptosporidium Attenuation across the Wastewater Treatment Train: Recycled Water Fit for Purpose.

Science.gov (United States)

King, Brendon; Fanok, Stella; Phillips, Renae; Lau, Melody; van den Akker, Ben; Monis, Paul

2017-03-01

Compliance with guideline removal targets for Cryptosporidium which do not provide any credit for the inactivation of oocysts through wastewater treatment processes can considerably increase the cost of providing recycled water. Here we present the application of an integrated assay to quantify both oocyst numbers and infectivity levels after various treatment stages at three Victorian and two South Australian (SA) wastewater treatment plants (WWTPs). Oocyst density in the raw sewage was commensurate with community disease burden, with early rounds of sampling capturing a widespread cryptosporidiosis outbreak in Victoria. The level of infectivity of oocysts in sewage was stable throughout the year but was significantly lower at the SA WWTPs. Removals across secondary treatment processes were seasonal, with poorer removals associated with inflow variability; however, no decrease in the oocyst infectivity was identified. For SA WWTPs, those oocysts remaining within the secondary treatment-clarified effluent were proportionally more infectious than those in raw sewage. Lagoon systems demonstrated significant inactivation or removal of oocysts, with attenuation being seasonal. Examination of a UV system emphasized its efficacy as a disinfectant barrier but conversely confirmed the importance of a multibarrier approach with the detection of infectious oocysts postdisinfection. The ability to characterize risk from infectious oocysts revealed that the risk from Cryptosporidium is significantly lower than previously thought and that its inclusion in quantitative risk assessments of reuse systems will more accurately direct the selection of treatment strategies and capital expenditure, influencing the sustainability of such schemes. IMPORTANCE Here we present the application of a recently developed integrated assay not only to quantify the removal of Cryptosporidium oocysts but also to quantify their infectivity across various treatment stages at five wastewater treatment

Consistent effects of a major QTL for thermal resistance in field-released Drosophila melanogaster

DEFF Research Database (Denmark)

Loeschcke, Volker; Kristensen, Torsten Nygård; Norry, Fabian M

2011-01-01

Molecular genetic markers can be used to identify quantitative trait loci (QTL) for thermal resistance and this has allowed characterization of a major QTL for knockdown resistance to high temperature in Drosophila melanogaster. The QTL showed trade-off associations with cold resistance under lab...... of field fitness at different environmental temperatures with genotypic variation in a QTL for thermal tolerance. Graphical abstract...

Environmental knowledge, environmental politics. Case studies from Canada and Western Europe

Energy Technology Data Exchange (ETDEWEB)

Clapperton, Jonathan; Piper, Liza (eds.)

2016-07-01

The ways in which we come to know the environment are always inherently political - as are the ways in which environmental knowledge is put to use in the world. Focusing on ''scientific knowledge'' and ''Indigenous knowledge,'' on knowledge obtained through work as well as through leisure, the contributions in this volume explore how environmental knowledge is acquired, constructed, and deployed to make political claims on or for the environment. This volume also shows how environmental knowledge is embedded in grassroots, national, and international political efforts to find solutions to environmental problems. These essays showcase examples from Canada and Western Europe, offering insights into how different forms of environmental knowledge and environmental politics come to be seen as legitimate or illegitimate. This volume contains nine topics: 1. Indigenous Ecological Knowledge and the Politics of Postcolonial Writing (Jonathan Clapperton); 2. Bitumen Exploration and the Southern Re-Inscription of Northeastern Alberta: 1875-1967 (Hereward Longley); 3. Pollution, Local Activism, and the Politics of Development in the Canadian North (John Sandlos and Arn Keeling); 4. Seeds of Knowledge: From Back-to-the-Land to Urban Gardening (Nancy Janovicek); 5. Between Stewardship and Exploitation: Private Tourism, State Parks, and Environmentalism (Jessica M. DeWitt); 6. Reflections on Water: Knowing a River (Marianna Dudley); 7. ''We Are as Gods'': The Green Technical Fix (Henry Trim); 8. Environmental Knowledge and Politics in Portugal: From Resistance to Incorporation (Margarida Queiros); 9. Coal in the Age of the Oil Sands (Liza Piper).

Environmental knowledge, environmental politics. Case studies from Canada and Western Europe

International Nuclear Information System (INIS)

Clapperton, Jonathan; Piper, Liza

2016-01-01

The ways in which we come to know the environment are always inherently political - as are the ways in which environmental knowledge is put to use in the world. Focusing on ''scientific knowledge'' and ''Indigenous knowledge,'' on knowledge obtained through work as well as through leisure, the contributions in this volume explore how environmental knowledge is acquired, constructed, and deployed to make political claims on or for the environment. This volume also shows how environmental knowledge is embedded in grassroots, national, and international political efforts to find solutions to environmental problems. These essays showcase examples from Canada and Western Europe, offering insights into how different forms of environmental knowledge and environmental politics come to be seen as legitimate or illegitimate. This volume contains nine topics: 1. Indigenous Ecological Knowledge and the Politics of Postcolonial Writing (Jonathan Clapperton); 2. Bitumen Exploration and the Southern Re-Inscription of Northeastern Alberta: 1875-1967 (Hereward Longley); 3. Pollution, Local Activism, and the Politics of Development in the Canadian North (John Sandlos and Arn Keeling); 4. Seeds of Knowledge: From Back-to-the-Land to Urban Gardening (Nancy Janovicek); 5. Between Stewardship and Exploitation: Private Tourism, State Parks, and Environmentalism (Jessica M. DeWitt); 6. Reflections on Water: Knowing a River (Marianna Dudley); 7. ''We Are as Gods'': The Green Technical Fix (Henry Trim); 8. Environmental Knowledge and Politics in Portugal: From Resistance to Incorporation (Margarida Queiros); 9. Coal in the Age of the Oil Sands (Liza Piper).

Expanding the eco-evolutionary context of herbicide resistance research.

Science.gov (United States)

Neve, Paul; Busi, Roberto; Renton, Michael; Vila-Aiub, Martin M

2014-09-01

The potential for human-driven evolution in economically and environmentally important organisms in medicine, agriculture and conservation management is now widely recognised. The evolution of herbicide resistance in weeds is a classic example of rapid adaptation in the face of human-mediated selection. Management strategies that aim to slow or prevent the evolution of herbicide resistance must be informed by an understanding of the ecological and evolutionary factors that drive selection in weed populations. Here, we argue for a greater focus on the ultimate causes of selection for resistance in herbicide resistance studies. The emerging fields of eco-evolutionary dynamics and applied evolutionary biology offer a means to achieve this goal and to consider herbicide resistance in a broader and sometimes novel context. Four relevant research questions are presented, which examine (i) the impact of herbicide dose on selection for resistance, (ii) plant fitness in herbicide resistance studies, (iii) the efficacy of herbicide rotations and mixtures and (iv) the impacts of gene flow on resistance evolution and spread. In all cases, fundamental ecology and evolution have the potential to offer new insights into herbicide resistance evolution and management. © 2014 Society of Chemical Industry.

Detection of infectious Cryptosporidium oocysts by cell culture: applicability to environmental samples

NARCIS (Netherlands)

Schets FM; Engels GB; During M; de Roda Husman AM; MGB

2004-01-01

Cryptosporidium is een van de belangrijkste veroorzakers van gastro-enteritis bij de mens. Cryptosporidium-infecties worden vaak via water overgedragen, dit kan zowel drinkwater als recreatiewater zijn. Bij schatting van de kans op infectie met Cryptosporidium na blootstelling aan drinkwater is

Detection of infectious Cryptosporidium oocysts by cell culture: applicability to environmental samples

NARCIS (Netherlands)

Schets FM; Engels GB; During M; Roda Husman AM de; MGB

2004-01-01

Cryptosporidium is one of the important causative agents of gastrointestinal illness in humans. Cryptosporidium infections are often waterborne and can be transmitted through drinking water or recreational water. Estimation of the risk of infection with Cryptosporidium after exposure to drinking

Genomics of antibiotic-resistance prediction in Pseudomonas aeruginosa.

Science.gov (United States)

Jeukens, Julie; Freschi, Luca; Kukavica-Ibrulj, Irena; Emond-Rheault, Jean-Guillaume; Tucker, Nicholas P; Levesque, Roger C

2017-06-02

Antibiotic resistance is a worldwide health issue spreading quickly among human and animal pathogens, as well as environmental bacteria. Misuse of antibiotics has an impact on the selection of resistant bacteria, thus contributing to an increase in the occurrence of resistant genotypes that emerge via spontaneous mutation or are acquired by horizontal gene transfer. There is a specific and urgent need not only to detect antimicrobial resistance but also to predict antibiotic resistance in silico. We now have the capability to sequence hundreds of bacterial genomes per week, including assembly and annotation. Novel and forthcoming bioinformatics tools can predict the resistome and the mobilome with a level of sophistication not previously possible. Coupled with bacterial strain collections and databases containing strain metadata, prediction of antibiotic resistance and the potential for virulence are moving rapidly toward a novel approach in molecular epidemiology. Here, we present a model system in antibiotic-resistance prediction, along with its promises and limitations. As it is commonly multidrug resistant, Pseudomonas aeruginosa causes infections that are often difficult to eradicate. We review novel approaches for genotype prediction of antibiotic resistance. We discuss the generation of microbial sequence data for real-time patient management and the prediction of antimicrobial resistance. © 2017 The Authors. Annals of the New York Academy of Sciences published by Wiley Periodicals Inc. on behalf of The New York Academy of Sciences.

The Association of Cryptosporidium parvum With Suspended Sediments: Implications for Transport in Surface Waters

Science.gov (United States)

Searcy, K. E.; Packman, A. I.; Atwill, E. R.; Harter, T.

2003-12-01

Understanding the transport and fate of microorganisms in surface waters is of vital concern in protecting the integrity and safety of municipal water supply systems. The human pathogen Cryptosporidium parvum is a particular public health interest, as it is ubiquitous in the surface waters of the United States, it can persist for long periods in the environment, and it is difficult to disinfect in water treatment plants. Due to its small size (5 um), low specific gravity (1.05 g/cm3), and negative surface charge, C. parvum oocysts are generally considered to move through watersheds from their source to drinking water reservoirs with little attenuation. However, the transport of the oocysts in surface waters may be mediated by interactions with suspended sediments. Batch experiments were conducted to determine the extent of C. parvum oocyst attachment to several inorganic and organic sediments under varying water chemical conditions, and settling column experiments were performed to demonstrate how these associations influence the effective settling velocity of C. parvum oocysts. Results from these experiments showed that C. parvum oocysts do associate with inorganic and organic sediments and often settle at the rate of the suspended sediment. The size and surface charge of the host suspended sediment influenced the extent of oocyst attachment as oocysts preferentially associated with particles greater than 3 um, and fewer oocysts associated with particles having a highly negative surface charge. Background water chemical conditions including ionic strength, ion composition, and pH did not have a significant effect on oocyst attachment to suspended sediments.

Resistance may be an important mechanism by which marine microbes respond to environmental toxicants*1

Science.gov (United States)

Capriulo, Gerard M.; Flanzenbaum, Jeffrey; Wurster, Charles F.; Rowland, R. George

1983-11-01

The hypothesis, that at least certain marine microbial organisms respond to toxic stress by the development of resistance, was tested using the hypotric marine ciliate Euplotes vannus Muller as the test organism. Resistance to polychlorinated biphenyls (PCB, Aroclor 1254) was developed in E. vannus by exposing the animals to progressively higher PCB concentrations during a period of several months. The resistance to PCB persisted for at least 80 days (greater than 40 generations) after final exposure. This suggests either that genetic selection or persistent (lasting over many cell division cycles) phenotypic trait modification, possibly in the form of Dauermodification, had occurred. If resistance were widespread among marine microbial organisms in polluted environments it would be an important consideration in evaluating the long-term biological impact of both natural and man-induced chemical stress.

Exploring Culturally Specific Drug Resistance Strategies of Hawaiian Youth in Rural Communities

Science.gov (United States)

Okamoto, Scott K.; Po'a-Kekuawela, Ka'ohinani; Chin, Coralee I. H.; Nebre, La Risa H.; Helm, Susana

2010-01-01

This qualitative study examined the drug resistance strategies of Hawaiian youth residing in rural communities in Hawai'i. Forty seven youth participated in 14 focus groups which focused on the social and environmental context of drug use for these youth. The findings indicated that there were 47 references to resistance strategies used in drug…

Designing Base and Subbase to Resist Environmental Effects on Pavements

Science.gov (United States)

2018-02-02

MnDOTs current pavement thickness design procedures do not characterize the effects of subgrade soil frost susceptibility. Previous research indicates frost action is the most severe environmental factor on pavement performance. The most accepted ...

Unravelling the resistance mechanism of lettuce against Nasonovia ribisnigri

OpenAIRE

Broeke, ten, C.J.M.

2013-01-01

Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically important pest of cultivated lettuce, Lactuca sativa L. Host plant resistance has been used since 1982 to control this aphid species and is mediated by the Nr-gene, originating from wild lettuce Lactuca virosa L. H...

Four new species of coccidia (Apicomplexa: Eimeriidae) from Owen Stanley Skinks, Papuascincus stanleyanus (Sauria: Scincidae), from Papua New Guinea

Science.gov (United States)

McAllister, Chris T.; Duszynski, Donald W.; Fisher, Robert N.; Austin, Christopher C.

2014-01-01

Between September and November 1991, 12 Owen Stanley skinks, Papuascincus stanleyanus (Booulenger) were collected from various localities on Papua New Guinea and examined for coccidians. Six (50%) were found to harbour four eimerians that we describe here as new. Oocysts of Eimeria burseyi sp. n. were elongate to ellipsoidal with a bilayered wall and measured (length x width, L x W) 36.0 x 24.0 microm, with a L/W ratio of 1.5. Both micropyle and oocyst residuum were absent, but a polar granule was present. Oocysts of Eimeria goldbergi sp. n. were ellipsoidal, with a bilayered wall, and measured 21.4 x 16.1 microm; L/W ratio was 1.3. Both micropyle and oocyst residuum were absent, but a single or fragmented polar granule was present. Oocysts of Eimeria boulengeri sp. n. were spheroidal to slightly subspheroidal, with a thin, single-layered wall that readily collapses, and measured 16.0 microm, L/W ratio was 1.0. Both micropyle and oocyst residuum were absent, but usually one (sometimes two) polar granule(s) were present. Oocysts of Eimeria niuginiensis sp. n. were oblong to tapered with a bilayered wall, and measured 20.0 x 13.1 microm; L/W ratio was 1.5. A micropyle, oocyst residuum and polar granule were absent. To our knowledge, these represent the only coccidians ever described from P. stanleyanus.

Comparison of Assays for Sensitive and Reproducible Detection of Cell Culture-Infectious Cryptosporidium parvum and Cryptosporidium hominis in Drinking Water

Science.gov (United States)

Di Giovanni, George D.; Rochelle, Paul A.

2012-01-01

This study compared the three most commonly used assays for detecting Cryptosporidium sp. infections in cell culture: immunofluorescent antibody and microscopy assay (IFA), PCR targeting Cryptosporidium sp.-specific DNA, and reverse transcriptase PCR (RT-PCR) targeting Cryptosporidium sp.-specific mRNA. Monolayers of HCT-8 cells, grown in 8-well chamber slides or 96-well plates, were inoculated with a variety of viable and inactivated oocysts to assess assay performance. All assays detected infection with low doses of flow cytometry-enumerated Cryptosporidium parvum oocysts, including infection with one oocyst and three oocysts. All methods also detected infection with Cryptosporidium hominis. The RT-PCR assay, IFA, and PCR assay detected infection in 23%, 25%, and 51% of monolayers inoculated with three C. parvum oocysts and 10%, 9%, and 16% of monolayers inoculated with one oocyst, respectively. The PCR assay was the most sensitive, but it had the highest frequency of false positives with mock-infected cells and inactivated oocysts. IFA was the only infection detection assay that did not produce false positives with mock-infected monolayers. IFA was also the only assay that detected infections in all experiments with spiked oocysts recovered from Envirochek capsules following filtration of 1,000 liters of treated water. Consequently, cell culture with IFA detection is the most appropriate method for routine and sensitive detection of infectious Cryptosporidium parvum and Cryptosporidium hominis in drinking water. PMID:22038611

Aggregata (Protozoa: Apicomplexa) infection in the common octopus Octopus vulgaris from the West Mediterranean Sea: The infection rates and possible effect of faunistic, environmental and ecological factors

Science.gov (United States)

Mayo-Hernández, E.; Barcala, E.; Berriatua, E.; García-Ayala, A.; Muñoz, P.

2013-10-01

Prevalence and distribution of the coccidian parasite Aggregata octopiana (Protozoa: Apicomplexa) in common octopus (Octopus vulgaris) in the Mediterranean Spanish coasts were studied. A total of 114 octopuses were sampled from 30 geographic sectors by trawl fleet, and whitish macroscopic oocysts typical of A. octopiana infection were recorded in 96% of octopuses in the digestive tract and mainly in intestine and spiral caecum. The univariate analysis showed that lesion extension varied according to specific octopus, environmental and faunistic variables. A subsequent multivariable analysis indicated that the risk of macroscopic lesions in the caecum was greater in males compared to females, in octopuses living in deeper compared to shallower waters and in hauls where the crustacean Pagurus excavatus was present. The study provides further evidence of the abundance of A. octopiana in octopus ecosystems urging for further studies to evaluate its health impact. The combined abundance of infected octopuses and P. excavatus merits attention.

Bacterial biofilms and antibiotic resistance

Directory of Open Access Journals (Sweden)

Liliana Caldas-Arias

2015-04-01

Full Text Available Biofilms give to bacteria micro-environmental benefits; confers protection against antimicrobials. Bacteria have antibiotic resistance by conventional and unusual mechanisms leading to delayed wound healing, to increase recurrent chronic infections and nosocomial contamination of medical devices. Objective: This narrative review aims to introduce the characteristics of Bacteria-biofilms, antimicrobial resistance mechanisms and potential alternatives for prevention and control of its formation. Methods: Search strategy was performed on records: PubMed / Medline, Lilacs, Redalyc; with suppliers such as EBSCO and thesaurus MeSH and DeCS. Conclusions: Knowledge and research performance of biofilm bacteria are relevant in the search of technology for detection and measuring sensitivity to antibiotics. The identification of Bacterial-biofilms needs no-traditional microbiological diagnosis.

Resistance Element Welding of Magnesium Alloy/austenitic Stainless Steel

Science.gov (United States)

Manladan, S. M.; Yusof, F.; Ramesh, S.; Zhang, Y.; Luo, Z.; Ling, Z.

2017-09-01

Multi-material design is increasingly applied in the automotive and aerospace industries to reduce weight, improve crash-worthiness, and reduce environmental pollution. In the present study, a novel variant of resistance spot welding technique, known as resistance element welding was used to join AZ31 Mg alloy to 316 L austenitic stainless steel. The microstructure and mechanical properties of the joints were evaluated. It was found that the nugget consisted of two zones, including a peripheral fusion zone on the stainless steel side and the main fusion zone. The tensile shear properties of the joints are superior to those obtained by traditional resistance spot welding.

Distribution of antibiotic resistance in urban watershed in Japan

International Nuclear Information System (INIS)

Ham, Young-Sik; Kobori, Hiromi; Kang, Joo-Hyon; Matsuzaki, Takayuki; Iino, Michiyo; Nomura, Hayashi

2012-01-01

Antibiotic-resistant E. coli concentrations showed large spatial and temporal variations, with greater concentrations observed in tributaries and downstream than in the upstream and midstream. Twenty percent of the geometric mean concentrations of antibiotic-resistant E. coli in the Tama River basin (Japan) exceeded the maximum acceptable concentration of indicator E. coli established by the USEPA. The indicator E. coli concentrations were positively correlated with those of antibiotic-resistant E. coli and multiple-antibiotic-resistant E. coli (resistance to more than two kinds of antibiotics), respectively, but not the detection rate of antibiotic-resistant E. coli, implying that use of antibiotic-resistant E. coli concentration rather than the detection rate can be a better approach for water quality assessment. Multiple-antibiotic-resistant E. coli is a useful indicator for estimating the resistance diffusion, water quality degradation and public health risk potential. This assessment provides beneficial information for setting national regulatory or environmental standards and managing integrated watershed areas. - Highlights: ► We extensively observed antibiotic-resistant E. coli (AREc) in Tama River (Japan). ► AREc count rather than the detection rate is better approach for water quality test. ► Multiple-AREc is resistant to the antibiotic to which single-AREc has no resistance. ► Multiple-AREc increase will accelerate the diffusion of antibiotic resistance. - Multiple-antibiotic-resistant E. coli in the watershed can cause the diffusion of conventionally rare antibiotic resistance.

Sea urchin coelomocytes are resistant to a variety of DNA damaging agents

International Nuclear Information System (INIS)

Loram, Jeannette; Raudonis, Renee; Chapman, Jecar; Lortie, Mae; Bodnar, Andrea

2012-01-01

Increasing anthropogenic activities are creating environmental pressures that threaten marine ecosystems. Effective environmental health assessment requires the development of rapid, sensitive, and cost-effective tools to predict negative impacts at the individual and ecosystem levels. To this end, a number of biological assays using a variety of cells and organisms measuring different end points have been developed for biomonitoring programs. The sea urchin fertilization/development test has been useful for evaluating environmental toxicology and it has been proposed that sea urchin coelomocytes represent a novel cellular biosensor of environmental stress. In this study we investigated the sensitivity of coelomocytes from the sea urchin Lytechinus variegatus to a variety of DNA-damaging agents including ultraviolet (UV) radiation, hydrogen peroxide (H 2 O 2 ), methylmethane sulfonate (MMS) and benzo[a]pyrene (BaP). LD 50 values determined for coelomocytes after 24 h of exposure to these DNA damaging agents indicated a high level of resistance to all treatments. Significant increases in the formation of apurinic/apyrimidinic (AP or abasic) sites in DNA were only detected using high doses of H 2 O 2 , MMS and UV radiation. Comparison of sea urchin coelomocytes with hemocytes from the gastropod mollusk Aplysia dactylomela and the decapod crustacean Panulirus argus indicated that sensitivity to different DNA damaging agents varies between species. The high level of resistance to genotoxic agents suggests that DNA damage may not be an informative end point for environmental health assessment using sea urchin coelomocytes however, natural resistance to DNA damaging agents may have implications for the occurrence of neoplastic disease in these animals.

Radiation-resistant bacteria and their application to metal and radionuclides bioremediation

International Nuclear Information System (INIS)

Wang Jianlong

2004-01-01

Microorganisms have a number of applications in the nuclear industry, which would benefit from the use of radiation-resistant microorganisms. Environmentally isolated bacteria have shown to be resistant to gamma irradiation up to a dose of 30,000 Gy. It has also been reported that the presence of ionizing radiation may induce radio-resistance in bacteria. Recent demonstrations of the removal and immobilization of inorganic contaminants by microbial transformations, sorption and mineralization show the potential of both natural and engineered microorganisms as bioremedial tools. This review is to provide an overview of the application of radiation-resistant bacteria to decontamination of metal and radionuclide. (authors)

Efflux pumps as antimicrobial resistance mechanisms.

Science.gov (United States)

Poole, Keith

2007-01-01

Antibiotic resistance continues to hamper antimicrobial chemotherapy of infectious disease, and while biocide resistance outside of the laboratory is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are not uncommon. Efflux mechanisms, both drug-specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials in important human pathogens. Multidrug efflux mechanisms are generally chromosome-encoded, with their expression typically resultant from mutations in regulatory genes, while drug-specific efflux mechanisms are encoded by mobile genetic elements whose acquisition is sufficient for resistance. While it has been suggested that drug-specific efflux systems originated from efflux determinants of self-protection in antibiotic-producing Actinomycetes, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, are appreciated as having an intended housekeeping function unrelated to drug export and resistance. Thus, it will be important to elucidate the intended natural function of these efflux mechanisms in order, for example, to anticipate environmental conditions or circumstances that might promote their expression and, so, compromise antimicrobial chemotherapy. Given the clinical significance of antimicrobial exporters, it is clear that efflux must be considered in formulating strategies for treatment of drug-resistant infections, both in the development of new agents, for example, less impacted by efflux or in targeting efflux directly with efflux inhibitors.

Different responses of soybean cyst nematode resistance between ...

Indian Academy of Sciences (India)

2016-12-02

Dec 2, 2016 ... 3Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan, Shandong 250100, People's Republic of ... SCN race 1 (HG types 2.5.7), while 7605 is highly susceptible. ... nomical and environmental friendly method to control ..... analysis and qualitative mapping of a major partial-resistance.

[Resistance to heavy metals in ruminal staphylococci].

Science.gov (United States)

Lauková, A

1994-01-01

Ruminal, coagulase-negative, urease and bacteriocin-like substances producing staphylococci were screened for their heavy metal ions and antibiotics resistance. All strains tested were resistant to disodium arsenate at a minimal inhibition concentration (MIC > 5 g/l) and cadmium sulphate (MIC > 4 g/l). MIC = 50-60 mg/l was determined in eight staphylococci screened in mercury chloride resistance test (Tab. I). Silver nitrate resistance was detected in seven of the bacteria used (MIC = 40-50 mg/l). All strains were novobiocin resistant. Staphylococcus cohnii subsp. urealyticum SCU 40 was found as a strain with resistance to all heavy metal ions and 5 antibiotics (Tab. II). In addition, this strain produced bacteriocin-like substance which inhibited growth of six indicators of different origin (Tab. II). The most of staphylococci were detected as heavy metal ion polyresistant strains and antibiotic polyresistant strains producing antimicrobial substances with inhibition effects against at least one indicator of different origin. These results represent the first information on heavy metal ion resistance in ruminal bacteria. They also show relation or coresistance between heavy metal ions and antibiotics. Resulting from this study, staphylococci can be used as a bioindicator model for animal environmental studies. In addition, it can be used for specific interactions studies within the framework of ruminal bacterial ecosystem and also mainly with regard to molecular genetic studies.

Vancomycin-Resistant Enterococci and Bacterial Community Structure following a Sewage Spill into an Aquatic Environment

Science.gov (United States)

Young, Suzanne; Nayak, Bina; Sun, Shan; Badgley, Brian D.; Rohr, Jason R.

2016-01-01

ABSTRACT Sewage spills can release antibiotic-resistant bacteria into surface waters, contributing to environmental reservoirs and potentially impacting human health. Vancomycin-resistant enterococci (VRE) are nosocomial pathogens that have been detected in environmental habitats, including soil, water, and beach sands, as well as wildlife feces. However, VRE harboring vanA genes that confer high-level resistance have infrequently been found outside clinical settings in the United States. This study found culturable Enterococcus faecium harboring the vanA gene in water and sediment for up to 3 days after a sewage spill, and the quantitative PCR (qPCR) signal for vanA persisted for an additional week. Culturable levels of enterococci in water exceeded recreational water guidelines for 2 weeks following the spill, declining about five orders of magnitude in sediments and two orders of magnitude in the water column over 6 weeks. Analysis of bacterial taxa via 16S rRNA gene sequencing showed changes in community structure through time following the sewage spill in sediment and water. The spread of opportunistic pathogens harboring high-level vancomycin resistance genes beyond hospitals and into the broader community and associated habitats is a potential threat to public health, requiring further studies that examine the persistence, occurrence, and survival of VRE in different environmental matrices. IMPORTANCE Vancomycin-resistant enterococci (VRE) are harmful bacteria that are resistant to the powerful antibiotic vancomycin, which is used as a last resort against many infections. This study followed the release of VRE in a major sewage spill and their persistence over time. Such events can act as a means of spreading vancomycin-resistant bacteria in the environment, which can eventually impact human health. PMID:27422829

Ekstrak Sambiloto Menurunkan Patogenesitas Ookista Eimeria Tenella

Directory of Open Access Journals (Sweden)

Yulia Yellita

2012-11-01

Full Text Available Eimeria tenella is one of the nine of Eimeria species, a pathogenic intraseluler protozoa causing aviancoccidiosis. Infection was initiated by the ingestion of sporulated oocysts. The aim of this study was toinvestigate the effect of E. tenella oocyst incubation in methanol extract of Andrographis paniculata beforeinfection in broiler performance. This research used 115 broiler DOC (CP 707 devided into five groups,each group consisted of 23 broilers. The infection with 1x105 oocyst were done at the 14th day old of chicken.The 1st group was placebo (KN, while the 2nd group was infected with unincubated oocyst (KP, and theother three groups i.e. : 3rd, 4th, 5th were infected with incubated oocyst in A. paniculata extract for 2, 4, and6 hours, respectively. The number of oocysts in feces were counted on day 5th to 14th post-infection, theheterophile and macrophages were counted from caecum histology preparation, by slaughtered threechickens of each of groups on the day 0,3,6.9, and 14 post infection, and accretion body weight wasmeasured by weighing chickens per week to five-week old chickens. The results of this study indicated thatthe incubation period the sporulated oocyst in the extract of A.paniculata for six hours before infection,reduced the number of oocysts production in the feces, the number of inflammatory cells (macrophages andheterophile in the cecum, and increases body weight (gain. In conclusion A.paniculata extract decreasedthe pathogenisity of E.tenella oocyst, so the extract of A.paniculata has good potential as anticoccidia. Itis high likely that A. paniculata extract has a potential to be anticoccidia.

A shift to organismal stress resistance in programmed cell death mutants.

Directory of Open Access Journals (Sweden)

Meredith E Judy

Full Text Available Animals have many ways of protecting themselves against stress; for example, they can induce animal-wide, stress-protective pathways and they can kill damaged cells via apoptosis. We have discovered an unexpected regulatory relationship between these two types of stress responses. We find that C. elegans mutations blocking the normal course of programmed cell death and clearance confer animal-wide resistance to a specific set of environmental stressors; namely, ER, heat and osmotic stress. Remarkably, this pattern of stress resistance is induced by mutations that affect cell death in different ways, including ced-3 (cell death defective mutations, which block programmed cell death, ced-1 and ced-2 mutations, which prevent the engulfment of dying cells, and progranulin (pgrn-1 mutations, which accelerate the clearance of apoptotic cells. Stress resistance conferred by ced and pgrn-1 mutations is not additive and these mutants share altered patterns of gene expression, suggesting that they may act within the same pathway to achieve stress resistance. Together, our findings demonstrate that programmed cell death effectors influence the degree to which C. elegans tolerates environmental stress. While the mechanism is not entirely clear, it is intriguing that animals lacking the ability to efficiently and correctly remove dying cells should switch to a more global animal-wide system of stress resistance.

Gastrointestinal parasites of canids, a latent risk to human health in Tunisia.

Science.gov (United States)

Oudni-M'rad, Myriam; Chaâbane-Banaoues, Raja; M'rad, Selim; Trifa, Fatma; Mezhoud, Habib; Babba, Hamouda

2017-06-05

Although data on the parasite environmental contamination are crucial to implement strategies for control and treatment, information about zoonotic helminths is very limited in Tunisia. Contamination of areas with canid faeces harboring infective parasite elements represents a relevant health-risk impact for humans. The aim of this study was to assess the environmental contamination with eggs and oocysts of gastrointestinal parasites of dogs and wild canids in Tunisia with special attention to those that can be transmitted to humans. One thousand two hundred and seventy faecal samples from stray dogs and 104 from wild canids (red foxes and golden jackals) were collected from different geographical regions throughout Tunisia. The helminth eggs and protozoan oocysts were concentrated by sucrose flotation and identified by microscopic examination. The most frequently observed parasites in dog samples were Toxocara spp. (27.2%), E. granulosus (25.8%), and Coccidia (13.1%). For wild canid faeces, the most commonly encountered parasites were Toxocara spp. (16.3%) followed by Capillaria spp. (9.6%). The parasite contamination of dog faeces varied significantly from one region to another in function of the climate. To our knowledge, the study highlights for the first time in Tunisia a serious environmental contamination by numerous parasitic stages infective to humans. Efforts should be made to increase the awareness of the contamination risk of such parasites in the environment and implement a targeted educational program.

Mega-mining in Mexico. Structural reforms and resistance

Directory of Open Access Journals (Sweden)

Darcy Tetreault

2013-11-01

Full Text Available This article analyzes the structural causes of social environmental conflicts around mega-mining in Mexico and describes the emergence and coordination of resistance movements. It argues that neoliberal reforms have facilitated ‘accumulation by dispossession’ on two levels: first, by transferring public resources in the form of mineral reserves and state-run mining companies to the private sector; and second, bydispossessing smallholder farmers and indigenous communities of their land, water and cultural landscapes, in order to allow mining companies to carry out their activities. Furthermore, it argues that some factions of the resistance movements reflect ‘the environmentalism of the poor’ insofar as they seek to maintain natural resources outside of the sphere of the capitalist mode of production. Through a systematic revision of newspaper articles, blogs and scholarly publications, 29 high-profile eco-territorial mining conflicts are identified and a preliminary analysis of these is provided.

Conflicting Perspectives in Trade and Environmental Negotiations

International Nuclear Information System (INIS)

Buchner, B.K.; Roson, R.

2002-09-01

International trade negotiations have recently tackled the issue of possible free trade restrictions, justified - among others - on the basis of environmental concerns. Also, some analyses of international environmental agreements (especially in the field of climate change) have highlighted the key role played by changes in the terms of trade in determining the cost of environmental policies. Yet, secondary effects of international trade remain disregarded in many environmental policies, whereas the introduction of environmental trade barriers has been resisted, arguing that this may hide a Trojan horse of a renewed protectionism. This paper reviews the debate on trade and the environment in the two fields of environmental and trade negotiations, highlighting the different and somewhat conflicting approach adopted in the two cases. A numerical general equilibrium model is used to illustrate how different 'perceptions' (translated in terms of alternative model closures) affect the use of instruments, the distributional impact of the various policies, and the strategic interplay between negotiators in international agreements

Conflicting Perspectives in Trade and Environmental Negotiations

Energy Technology Data Exchange (ETDEWEB)

Buchner, B.K. [Fondazione Eni Enrico Mattei FEEM, Milan (Italy); Roson, R. [Economics Department, Ca' Foscari University, Venice (Italy)

2002-09-01

International trade negotiations have recently tackled the issue of possible free trade restrictions, justified - among others - on the basis of environmental concerns. Also, some analyses of international environmental agreements (especially in the field of climate change) have highlighted the key role played by changes in the terms of trade in determining the cost of environmental policies. Yet, secondary effects of international trade remain disregarded in many environmental policies, whereas the introduction of environmental trade barriers has been resisted, arguing that this may hide a Trojan horse of a renewed protectionism. This paper reviews the debate on trade and the environment in the two fields of environmental and trade negotiations, highlighting the different and somewhat conflicting approach adopted in the two cases. A numerical general equilibrium model is used to illustrate how different 'perceptions' (translated in terms of alternative model closures) affect the use of instruments, the distributional impact of the various policies, and the strategic interplay between negotiators in international agreements.

Is Earth F**ked? Dynamical Futility of Global Environmental Management and Possibilities for Sustainability via Direct Action Activism

Science.gov (United States)

wErnEr, B.

2012-12-01

Environmental challenges are dynamically generated within the dominant global culture principally by the mismatch between short-time-scale market and political forces driving resource extraction/use and longer-time-scale accommodations of the Earth system to these changes. Increasing resource demand is leading to the development of two-way, nonlinear interactions between human societies and environmental systems that are becoming global in extent, either through globalized markets and other institutions or through coupling to global environmental systems such as climate. These trends are further intensified by dissipation-reducing technological advances in transactions, communication and transport, which suppress emergence of longer-time-scale economic and political levels of description and facilitate long-distance connections, and by predictive environmental modeling, which strengthens human connections to a short-time-scale virtual Earth, and weakens connections to the longer time scales of the actual Earth. Environmental management seeks to steer fast scale economic and political interests of a coupled human-environmental system towards longer-time-scale consideration of benefits and costs by operating within the confines of the dominant culture using a linear, engineering-type connection to the system. Perhaps as evidenced by widespread inability to meaningfully address such global environmental challenges as climate change and soil degradation, nonlinear connections reduce the ability of managers to operate outside coupled human-environmental systems, decreasing their effectiveness in steering towards sustainable interactions and resulting in managers slaved to short-to-intermediate-term interests. In sum, the dynamics of the global coupled human-environmental system within the dominant culture precludes management for stable, sustainable pathways and promotes instability. Environmental direct action, resistance taken from outside the dominant culture, as in

Development and evaluation of a HEPA filter for increased strength and resistance to elevated temperature

International Nuclear Information System (INIS)

Gilbert, H.; Bergman, W.; Fretthold, J.K.

1992-01-01

We have developed an improved HEPA filter for increased strength and resistance to elevated temperature to improve the reliability of HEPA filters under accident conditions. The improvements to the HEPA filter consist of a silicone rubber sealant and a new HEPA medium reinforced with a glass cloth. Several prototype filters were built and evaluated for temperature and pressure resistance and resistance to rough handling. The temperature resistance test consisted of exposing the HEPA filter to 1,000 scan at 700 degrees F for five minutes. The pressure resistance test consisted of exposing the HEPA filter to a differential pressure of 10 in. w.g. using a water saturated air flow at 95 degrees F. For the rough handling test, we used a vibrating machine designated the Q110. DOP filter efficiency tests were performed before and after each of the environmental tests. In addition to following the standard practice of using a separate new filter for each environmental test, we also subjected the same filter to the elevated temperature test followed by the pressure resistance test. The efficiency test results show that the improved HEPA filter is significantly better than the standard HEPA filter

A Novel Radiation-Resistant Yeast, Filobasidium elegans RRY1

Energy Technology Data Exchange (ETDEWEB)

Singh, Harinder; Kim, Ha Ram; Song, Hyun Pa; Lim, Sang Yong; Kim, Dong Ho [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2012-05-15

The tolerance to ionizing radiation stress is present among different classes and species of organisms. As listed by Rainey et al., ionizing radiation resistant organisms were isolated from a variety of different sources like processed/canned food items, paper industry, soil and water samples. Apart from extensively reported bacteria and Archea group, many fungal species like Aspergillus, Curvularia, Alternaria, Cryptococcus, and Ustilago maydis have been found to be resistant to ionizing radiation. However, different environmental sources are constantly been explored for novel radioresistant organisms, which can help in understanding the molecular mechanism behind these extreme stress responses. On the basis of this, present study was initiated to find novel radiation resistant yeast from sea water source

Comparative susceptibility of introduced forest-dwelling mosquitoes in Hawai'i to avian malaria, Plasmodium relictum

Science.gov (United States)

Lapointe, D.A.; Goff, M.L.; Atkinson, C.T.

2005-01-01

To identify potential vectors of avian malaria in Hawaiian native forests, the innate susceptibility of Aedes albopictus, Wyeomyia mitchellii, and Culex quinquefasciatus from 3 geographical sites along an altitudinal gradient was evaluated using local isolates of Plasmodium relictum. Mosquitoes were dissected 5-8 and 9-13 days postinfective blood meal and microscopically examined for oocysts and salivary-gland sporozoites. Sporogony was completed in all 3 species, but prevalence between species varied significantly. Oocysts were detected in 1-2% and sporozoites in 1-7% of Aedes albopictus that fed on infected ducklings. Wyeomyia mitchellii was slightly more susceptible, with 7-19% and 7% infected with oocysts and sporozoites, respectively. In both species, the median oocyst number was 5 or below. This is only the second Wyeomyia species reported to support development of a malarial parasite. Conversely, Culex quinquefasciatus from all 3 sites proved very susceptible. Prevalence of oocysts and sporozoites consistently exceeded 70%, regardless of gametocytemia or origin of the P. relictum isolate. In trials for which a maximum 200 oocysts were recorded, the median number of oocysts ranged from 144 to 200. It was concluded that Culex quinquefasciatus is the primary vector of avian malaria in Hawai'i. ?? American Society of Parasitologists 2005.

Human Challenge Pilot Study with Cyclospora cayetanensis

OpenAIRE

Alfano-Sobsey, Edith M.; Eberhard, Mark L.; Seed, John R.; Weber, David J.; Won, Kimberly Y.; Nace, Eva K.; Moe, Christine L.

2004-01-01

We describe a pilot study that attempted to infect human volunteers with Cyclospora cayetanensis. Seven healthy volunteers ingested an inoculum of Cyclospora oocysts (approximately 200–49,000 oocysts). The volunteers did not experience symptoms of gastroenteritis, and no oocysts were detected in any stool samples during the 16 weeks volunteers were monitored.

High Prevalence of Antimicrobial-resistant Gram-negative Colonization in Hospitalized Cambodian Infants.

Science.gov (United States)

Turner, Paul; Pol, Sreymom; Soeng, Sona; Sar, Poda; Neou, Leakhena; Chea, Phal; Day, Nicholas Pj; Cooper, Ben S; Turner, Claudia

2016-08-01

Antimicrobial-resistant Gram-negative infections are a significant cause of mortality in young infants. We aimed to determine characteristics of, and risk factors for, colonization and invasive infection caused by 3rd generation cephalosporin (3GC) or carbapenem-resistant organisms in outborn infants admitted to a neonatal unit (NU) in Cambodia. During the first year of operation, patients admitted to the Angkor Hospital for Children NU, Siem Reap, Cambodia, underwent rectal swabbing on admission and twice weekly until discharge. Swabs were taken also from 7 environmental sites. Swabs were cultured to identify 3GC or carbapenem-resistant Acinetobacter sp., Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. The study included 333 infants with a median age at NU admission of 10 days (range, 0-43). Colonization by ≥1 3GC-resistant organism was detected in 85.9% (286/333). Admission swabs were collected in 289 infants: 61.9% were colonized by a 3GC-resistant organism at the time of admission, and a further 23.2% were colonized during hospitalization, at a median of 4 days [95% confidence interval: 3-5]. Probiotic treatment (hazard ratio: 0.58; 95% confidence interval: 0.35-0.98) was associated with delayed colonization. Colonization by a carbapenem-resistant organism occurred in 25 (7.5%) infants. Six infants had NU-associated K. pneumoniae bacteremia; phenotypically identical colonizing strains were found in 3 infants. Environmental colonization occurred early. Colonization by antimicrobial-resistant Gram-negative organisms occurred early in hospitalized Cambodian infants and was associated with subsequent invasive infection. Trials of potential interventions such as probiotics are needed.

Sea urchin coelomocytes are resistant to a variety of DNA damaging agents

Energy Technology Data Exchange (ETDEWEB)

Loram, Jeannette; Raudonis, Renee; Chapman, Jecar; Lortie, Mae [Bermuda Institute of Ocean Sciences, St. George' s, Bermuda, GE 01 (Bermuda); Bodnar, Andrea, E-mail: andrea.bodnar@bios.edu [Bermuda Institute of Ocean Sciences, St. George' s, Bermuda, GE 01 (Bermuda)

2012-11-15

Increasing anthropogenic activities are creating environmental pressures that threaten marine ecosystems. Effective environmental health assessment requires the development of rapid, sensitive, and cost-effective tools to predict negative impacts at the individual and ecosystem levels. To this end, a number of biological assays using a variety of cells and organisms measuring different end points have been developed for biomonitoring programs. The sea urchin fertilization/development test has been useful for evaluating environmental toxicology and it has been proposed that sea urchin coelomocytes represent a novel cellular biosensor of environmental stress. In this study we investigated the sensitivity of coelomocytes from the sea urchin Lytechinus variegatus to a variety of DNA-damaging agents including ultraviolet (UV) radiation, hydrogen peroxide (H{sub 2}O{sub 2}), methylmethane sulfonate (MMS) and benzo[a]pyrene (BaP). LD{sub 50} values determined for coelomocytes after 24 h of exposure to these DNA damaging agents indicated a high level of resistance to all treatments. Significant increases in the formation of apurinic/apyrimidinic (AP or abasic) sites in DNA were only detected using high doses of H{sub 2}O{sub 2}, MMS and UV radiation. Comparison of sea urchin coelomocytes with hemocytes from the gastropod mollusk Aplysia dactylomela and the decapod crustacean Panulirus argus indicated that sensitivity to different DNA damaging agents varies between species. The high level of resistance to genotoxic agents suggests that DNA damage may not be an informative end point for environmental health assessment using sea urchin coelomocytes however, natural resistance to DNA damaging agents may have implications for the occurrence of neoplastic disease in these animals.

Environmental and social impacts of wind energy

DEFF Research Database (Denmark)

Borch, Kristian; Clausen, Niels-Erik; Ellis, Geraint

2014-01-01

The most common reasons for non- technical delays to wind energy projects are local resistance and poor strategic spatial planning. This chapter looks at the environmental and social impacts of wind energy and discusses how the public can gain trust in the public planning and private project...

Potential Impact of the Resistance to Quaternary Ammonium Disinfectants on the Persistence of Listeria monocytogenes in Food Processing Environments.

Science.gov (United States)

Martínez-Suárez, Joaquín V; Ortiz, Sagrario; López-Alonso, Victoria

2016-01-01

The persistence of certain strains of Listeria monocytogenes, even after the food processing environment has been cleaned and disinfected, suggests that this may be related to phenomena that reduce the concentration of the disinfectants to subinhibitory levels. This includes (i) the existence of environmental niches or reservoirs that are difficult for disinfectants to reach, (ii) microorganisms that form biofilms and create microenvironments in which adequate concentrations of disinfectants cannot be attained, and (iii) the acquisition of resistance mechanisms in L. monocytogenes, including those that lead to a reduction in the intracellular concentration of the disinfectants. The only available data with regard to the resistance of L. monocytogenes to disinfectants applied in food production environments refer to genotypic resistance to quaternary ammonium compounds (QACs). Although there are several well-characterized efflux pumps that confer resistance to QACs, it is a low-level resistance that does not generate resistance to QACs at the concentrations applied in the food industry. However, dilution in the environment and biodegradation result in QAC concentration gradients. As a result, the microorganisms are frequently exposed to subinhibitory concentrations of QACs. Therefore, the low-level resistance to QACs in L. monocytogenes may contribute to its environmental adaptation and persistence. In fact, in certain cases, the relationship between low-level resistance and the environmental persistence of L. monocytogenes in different food production chains has been previously established. The resistant strains would have survival advantages in these environments over sensitive strains, such as the ability to form biofilms in the presence of increased biocide concentrations.

Sulfonamide-resistant bacteria and their resistance genes in soils fertilized with manures from Jiangsu Province, Southeastern China.

Directory of Open Access Journals (Sweden)

Na Wang

Full Text Available Antibiotic-resistant bacteria and genes are recognized as new environmental pollutants that warrant special concern. There were few reports on veterinary antibiotic-resistant bacteria and genes in China. This work systematically analyzed the prevalence and distribution of sulfonamide resistance genes in soils from the environments around poultry and livestock farms in Jiangsu Province, Southeastern China. The results showed that the animal manure application made the spread and abundance of antibiotic resistance genes (ARGs increasingly in the soil. The frequency of sulfonamide resistance genes was sul1 > sul2 > sul3 in pig-manured soil DNA and sul2 > sul1 > sul3 in chicken-manured soil DNA. Further analysis suggested that the frequency distribution of the sul genes in the genomic DNA and plasmids of the SR isolates from manured soil was sul2 > sul1 > sul3 overall (p<0.05. The combination of sul1 and sul2 was the most frequent, and the co-existence of sul1 and sul3 was not found either in the genomic DNA or plasmids. The sample type, animal type and sampling time can influence the prevalence and distribution pattern of sulfonamide resistance genes. The present study also indicated that Bacillus, Pseudomonas and Shigella were the most prevalent sul-positive genera in the soil, suggesting a potential human health risk. The above results could be important in the evaluation of antibiotic-resistant bacteria and genes from manure as sources of agricultural soil pollution; the results also demonstrate the necessity and urgency of the regulation and supervision of veterinary antibiotics in China.

Effective Interfacially Polymerized Polyester Solvent Resistant Nanofiltration Membrane from Bioderived Materials

KAUST Repository

Abdellah, Mohamed H.; Perez Manriquez, Liliana; Puspasari, Tiara; Scholes, Colin A.; Kentish, Sandra E.; Peinemann, Klaus-Viktor

2018-01-01

Utilization of sustainable and environmentally friendly solvents for the preparation of membranes has attracted growing interest in recent years. In this work, a polyester thin film composite solvent resistant nanofiltration (SRNF) membrane

Effects of artemisinin in broiler chickens challenged with Eimeria acervulina, E. maxima and E. tenella in battery trials.

Science.gov (United States)

Pop, Loredana; Györke, Adriana; Tǎbǎran, Alexandru Flaviu; Dumitrache, Mirabela Oana; Kalmár, Zsuzsa; Magdaş, Cristian; Mircean, Viorica; Zagon, Diana; Balea, Anamaria; Cozma, Vasile

2015-12-15

Four experiments were conceived in order to test the efficacy of artemisinin, a sesquiterpene lactone derived from Artemisia annua, in single experimental infection of broiler chickens with Eimeria acervulina (1 × 10(5) oocysts), Eimeria maxima (5 × 10(4) oocysts) or Eimeria tenella (1 × 10(4) oocysts), and mixed infection with all 3 species (3.2 × 10(4) Eimeria spp. oocysts). For each experiment, three different dosages of artemisinin (5, 50 and 500 ppm) were compared with a negative control (uninfected, unmedicated), a positive control (infected, unmedicated) and a classical anticoccidial (monensin). The weight gain (WG), feed conversion ratio (FCR), oocysts shedded per gram of feces (OPG), lesion score, oocysts sporulation rates and mortality rate were recorded in all groups. The dosage of 5 ppm of artemisinin improved the WG and FCR for the chickens infected with E. acervulina. The OPG was significantly decreased in all the groups medicated with artemisinin and challenged with a mixed infection (p ≤ 0.01). The lesion score of the chickens challenged with Eimeria was reduced by different concentrations of artemisinin, depending on the species involved, but this compound did not have a positive effect on the lesions caused by E. acervulina. Histopathological analysis revealed superficial erosions of the intestinal mucosa, mixt. mononuclear and heterophilic inflammatory infiltrate in the lamina propria and intralesional presence of various developmental stages of parasite in groups infected with Eimeria spp.The sporulation rate of E. acervulina and E. maxima oocysts was significantly affected by 500 ppm of artemisinin, whilst the dosage of 5 ppm affected the sporulation of E. tenella oocysts. These data suggest that artemisinin is not effective against single eimerian infections but could be used as an alternative in mixed coccidiosis, especially if its effect on the oocysts sporulation would be fully investigated. Copyright © 2015 Elsevier B.V. All rights

Unravelling the resistance mechanism of lettuce against Nasonovia ribisnigri

NARCIS (Netherlands)

Broeke, ten C.J.M.

2013-01-01

Aphids are serious pests of crop plant species, and host plant resistance is often the most effective and environmentally friendly control strategy to control these pests. One of these aphid pests is the black currant - lettuce aphid, Nasonovia ribisnigri (Mosely), an economically

Potential Sources and Transmission of Salmonella and Antimicrobial Resistance in Kampala, Uganda.

Directory of Open Access Journals (Sweden)

Josephine A Afema

Full Text Available In sub‒Saharan Africa, non‒typhoidal Salmonellae (NTS cause invasive disease particularly in children and HIV infected adults, but the disease epidemiology is poorly understood. Between 2012 and 2013, we investigated NTS sources and transmission in Kampala. We detected Salmonella in 60% of the influent and 60% of the effluent samples from a wastewater treatment plant and 53.3% of the influent and 10% of the effluent samples from waste stabilization ponds that serve the human population; 40.9% of flush‒water samples from ruminant slaughterhouses, 6.6% of the poultry fecal samples from live bird markets and 4% of the fecal samples from swine at slaughter; and in 54.2% of the water samples from a channel that drains storm-water and effluents from the city. We obtained 775 Salmonella isolates, identified 32 serovars, and determined resistance to 15 antimicrobials. We genotyped common serovars using multiple‒locus variable number tandem repeats analysis or pulsed‒field gel electrophoresis. In addition, we analyzed 49 archived NTS isolates from asymptomatic livestock and human clinical cases. Salmonella from ruminant and swine sources were mostly pan‒susceptible (95% while poultry isolates were generally more resistant. Salmonella Kentucky isolated from poultry exhibited extensive drug resistance characterized by resistance to 10 antimicrobials. Interestingly, similar genotypes of S. Kentucky but with less antimicrobial resistance (AMR were found in poultry, human and environmental sources. The observed AMR patterns could be attributed to host or management factors associated with production. Alternatively, S. Kentucky may be prone to acquiring AMR. The factors driving AMR remain poorly understood and should be elucidated. Overall, shared genotypes and AMR phenotypes were found in NTS from human, livestock and environmental sources, suggesting zoonotic and environmental transmissions most likely occur. Information from this study could be

democratic approaches to environmental education: dream or ...

African Journals Online (AJOL)

cultural notions and values. However, the .... tures, but able to resist dominant hegemonic influ- ences and, thus ... Given the discussion above, what are the possibilities and constraints ... variety of local environmental problems and then identified an issue .... Teaching in this way devalues concepts such as democracy by ...

Microbial pollution in wildlife: Linking agricultural manuring and bacterial antibiotic resistance in red-billed choughs.

Science.gov (United States)

Blanco, Guillermo; Lemus, Jesús A; Grande, Javier

2009-05-01

The spread of pathogens in the environment due to human activities (pathogen pollution) may be involved in the emergence of many diseases in humans, livestock and wildlife. When manure from medicated livestock and urban effluents is spread onto agricultural land, both residues of antibiotics and bacteria carrying antibiotic resistance may be introduced into the environment. The transmission of bacterial resistance from livestock and humans to wildlife remains poorly understood even while wild animals may act as reservoirs of resistance that may be amplified and spread in the environment. We determined bacterial resistance to antibiotics in wildlife using the red-billed chough Pyrrhocorax pyrrhocorax as a potential bioindicator of soil health, and evaluated the role of agricultural manuring with waste of different origins in the acquisition and characteristics of such resistance. Agricultural manure was found to harbor high levels of bacterial resistance to multiple antibiotics. Choughs from areas where manure landspreading is a common agricultural practice harbor a high bacterial resistance to multiple antibiotics, resembling the resistance profile found in the waste (pig slurry and sewage sludge) used in each area. The transfer of bacterial resistance to wildlife should be considered as an important risk for environmental health when agricultural manuring involves fecal material containing multiresistant enteric bacteria including pathogens from livestock operations and urban areas. The assessment of bacterial resistance in wild animals may be valuable for the monitoring of environmental health and for the management of emergent infectious diseases influenced by the impact of different human activities in the environment.

An outbreak of vancomycin-resistant Enterococcus faecium in an acute care pediatric hospital: Lessons from environmental screening and a case-control study

Science.gov (United States)

Drews, Steven J; Richardson, Susan E; Wray, Rick; Freeman, Renee; Goldman, Carol; Streitenberger, Laurie; Stevens, Derek; Goia, Cristina; Kovach, Danuta; Brophy, Jason; Matlow, Anne G

2008-01-01

BACKGROUND The present study describes a vancomycin-resistant enterococci (VRE) outbreak investigation and a case-control study to identify risk factors for VRE acquisition in a tertiary care pediatric hospital. OBJECTIVE To report an outbreak investigation and a case-control study to identify risk factors for VRE colonization or infection in hospitalized children. METHODS Screening for VRE cases was performed by culture or polymerase chain reaction. A case-control study of VRE-colonized patients was undertaken. Environmental screening was performed using standard culture and susceptibility methods, with pulsed-field gel electrophoresis to determine relationships between VRE isolates. Statistical analysis was performed using SAS version 9.0 (SAS Institute Inc, USA). RESULTS Thirty-four VRE-positive cases were identified on 10 wards between February 28, 2005, and May 27, 2005. Pulsed-field gel electrophoresis analysis confirmed a single outbreak strain that was also isolated from a video game found on one affected ward. Multivariate analysis identified cephalosporin use as the major risk factor for VRE colonization. CONCLUSIONS In the present study outbreak, VRE colonization was significantly associated with cephalosporin use. Because shared recreational items and environmental surfaces may be colonized by VRE, they warrant particular attention in housekeeping protocols, particularly in pediatric institutions. PMID:19412380

Comparison of metals and tetracycline as selective agents for development of tetracycline resistant bacterial communities in agricultural soil

DEFF Research Database (Denmark)

Song, Jianxiao; Rensing, Christopher; Holm, Peter Engelund

2017-01-01

Environmental selection of antibiotic resistance may be caused by either antibiotic residues or coselecting agents. Using a strictly controlled experimental design, we compared the ability of metals (Cu or Zn) and tetracycline to (co)select for tetracycline resistance in bacterial communities. Soil...... microcosms were established by amending agricultural soil with known levels of Cu, Zn, or tetracycline known to represent commonly used metals and antibiotics for pig farming. Soil bacterial growth dynamics and bacterial community-level tetracycline resistance were determined using the [(3)H......]leucine incorporation technique, whereas soil Cu, Zn, and tetracycline exposure were quantified by a panel of whole-cell bacterial bioreporters. Tetracycline resistance increased significantly in soils containing environmentally relevant levels of Cu (≥365 mg kg(-1)) and Zn (≥264 mg kg(-1)) but not in soil spiked...

Anthelmintics Resistance; How to Overcome it?

Directory of Open Access Journals (Sweden)

Hatem A Shalaby

2013-03-01

Full Text Available Many parasitic helminthes of veterinary importance have genetic features that favor development of anthelmintic resistance, this becoming a major worldwide constrain in livestock production. The develop­ment of anthelmintic resistance poses a large threat to future production and welfare of graz­ing animals. Development of variable degrees of resistance among different species of gastrointes­tinal nematodes has been reported for all the major groups of anthelmintic drugs. It has been ob­served that frequent usage of the same group of anthelmintic; use of anthelmintics in sub-optimal doses, prophylactic mass treatment of domestic animals and frequent and continuous use of a single drug have contributed to the widespread development of anthelmintic resistance in helminthes. The degree and extent of this problem especially with respect to multidrug resistance in nematode popula­tions is likely to increase. Maintaining parasites in refugia and not exposed to anthelmintics, seems to be a key point in controlling and delaying the development of resistance, because the suscepti­ble genes are preserved. Targeted selective treatments attract the interest of scientists to­wards this direction. Additionally, adoption of strict quarantine measures and a combination drug strategy are two important methods of preventing of anthelmintic resistance. Experience from the development of anthelmintic resistance suggests that modern control schemes should not rely on sole use of anthelmintics, but employ other, more complex and sustainable recipes, including parasite resistant breeds, nutrition, pasture management, nematode-trapping fungi, antiparasitic vaccines and botanical dewormers. Most of them reduce reliance on the use of chemicals and are environmental friendly. Finally, if new anthelmintic products are released, an important question will be raised about how they should be used. It is suggested that slowing the development of resistance to a new

Abrasion Resistance and Mechanical Properties of Waste-Glass-Fiber-Reinforced Roller-compacted Concrete

Science.gov (United States)

Yildizel, S. A.; Timur, O.; Ozturk, A. U.

2018-05-01

The potential use of waste glass fibers in roller-compacted concrete (RCC) was investigated with the aim to improve its performance and reduce environmental effects. The research was focused on the abrasion resistance and compressive and flexural strengths of the reinforced concrete relative to those of reference mixes without fibers. The freeze-thaw resistance of RCC mixes was also examined. It was found that the use of waste glass fibers at a rate of 2 % increased the abrasion resistance of the RCC mixes considerably.

Electrical resistivity of nanoporous gold modified with thiol self-assembled monolayers

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Hakamada, Masataka, E-mail: hakamada.masataka.3x@kyoto-u.ac.jp; Kato, Naoki, E-mail: katou.naoki.75w@st.kyoto-u.ac.jp; Mabuchi, Mamoru, E-mail: mabuchi@energy.kyoto-u.ac.jp

2016-11-30

Highlights: • Nanoporous gold is modified with thiol-containing self-assembled monolayers. • The electrical resistivity of the thiol-modified nanoporous gold increases. • The electrical resistivity increases with increasing thiol concentration. • Monolayer tail groups enhance the atmosphere dependence of electrical resistivity. - Abstract: The electrical resistivity of nanoporous gold (NPG) modified with thiol self-assembled monolayers (SAMs) has been measured at 298 K using a four-probe method. We found that the adsorption of thiol SAMs increases the electrical resistivity of NPG by up to 22.2%. Dependence of the electrical resistivity on the atmosphere (air or water) was also observed in SAMs-modified NPG, suggesting that the electronic states of the tail groups affect the electrons of the binding sulfur and adjacent surface gold atoms. The present results suggest that adsorption of thiol molecules can influence the behavior of the conducting electrons in NPG and that modification of NPG with SAMs may be useful for environmental sensing.

Eimeria species (Apicomplexa: Eimeriidae of podocnemis expansa (Schweigger and geochelone denticulata (LINN. from Amazonian Brazil (Reptilia: Chelonia

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Ralph Lainson

1990-12-01

Full Text Available Eimeria lagunculata, Eimeria mammiformis and Eimeria podocnemis n. spp., are described from the faeces of the fresh-water turtle Podocnemis expansa, in Pará State, north Brasil. Oocysts of E. lagunculata are ellipsoidal, 19.2 x 12.8 (17.0-20.7 x 11.8-14.1 mum, shape-index (= length/ width 1.5 (1.4-1.7. Oocyst wall about 0.5-0.7 mum thick, with a prominent stopper-like micropyle at one pole. No oocyst residuum and no polar body. Sporocysts elongate ellipsoidal, 11.0 x 5.4 (10.4-11.8 x 5.2-6.0 mum, shape-index 2.0 (1.8-2.1: no Stieda body. A compact, ellipsoidal sporocyst residuum lies between the two sporozoites, which possess a posterior and an anterior refractile body. Oocysts of E. mammiformis broadly ellipsoidal, 30.0 x 19.4 (23.0-37.0 x 16.3-21.5 mum, shape-index 1.5 (1.1-1.9. Oocyst wall about 0.7 mum thick, with a prominent micropyle: no oocyst residuum and rarely a single polar body. Sporocysts ellipsoidal, 15.3 x 7.9 (14.8-17.0 x 7.4-9.6 mum, shape-index 2.0 (1.8-2.2, with a tiny Stieda body. Sporocyst residuum bulky, ellipsoidal: sporozoites with two conspicuous refractile bodies. E. podocnemis has broadly ellipsoidal oocysts, 17.0 x 12.8 (14.8-19.2 x 11.8-14.1 mum, shape-index 1.3 (1.1-1.4. Oocyst wall about 0.5-0.7 mum thick, with no micropyle. No oocyst residuum, but always a single polar body. Sporocysts ellipsoidal, 9.7 x 5.2 (8.9-10.4 x 4.4-6.0 mum, shape-index 1.9 (1.6-2.0, with no Stieda body. Sporocyst residuum bulky, ellipsoidal: sporocysts with 2 refractile bodies. Eimeria carinii n. sp., is recorded from the tortoise Geochelone denticulata, also from Pará. Oocyst wall about 1.2 mum thicl. No micropyle. Oocyst residuum limited to a number (about 10-20 of scattered granules: no polar body. Sporocysts broadly ellipsoidal, and with no Stieda body: they measure 8,8 x 7.3 (8.0-9.0 x 7.0-7.5 mum, shape-index 1.2 (1.1-1.3. Sporocyst residuum bulky, spherical to ellipsoidal: sporozoites possess both posterior and anterior

Assessing population and environmental effects on thermal resistance in Drosophila melanogaster using ecologically relevant assays