Distribution and characterization of ampicillin- and tetracycline-resistant Escherichia coli from feedlot cattle fed subtherapeutic antimicrobials

<p>Abstract</p> <p>Background</p> <p>Feedlot cattle in North America are routinely fed subtherapeutic levels of antimicrobials to prevent disease and improve the efficiency of growth. This practice has been shown to promote antimicrobial resistance (AMR) in subpopulations of intestinal microflora including <it>Escherichia coli</it>. To date, studies of AMR in feedlot production settings have rarely employed selective isolation, therefore yielding too few AMR isolates to enable characterization of the emergence and nature of AMR in <it>E. coli </it>as an indicator bacterium. <it>E. coli </it>isolates (<it>n </it>= 531) were recovered from 140 cattle that were housed (10 animals/pen) in 14 pens and received no dietary antimicrobials (control - 5 pens, CON), or were intermittently administered subtherapeutic levels of chlortetracycline (5 pens-T), chlortetracycline + sulfamethazine (4 pens-TS), or virginiamycin (5 pens-V) for two separate periods over a 9-month feeding period. Phenotype and genotype of the isolates were determined by susceptibility testing and pulsed field gel electrophoresis and distribution of characterized isolates among housed cattle reported. It was hypothesized that the feeding of subtherapeutic antibiotics would increase the isolation of distinct genotypes of AMR <it>E. coli </it>from cattle.</p> <p>Results</p> <p>Overall, patterns of antimicrobial resistance expressed by <it>E. coli </it>isolates did not change among diet groups (CON vs. antibiotic treatments), however; isolates obtained on selective plates (i.e., M^A,M^T), exhibited multi-resistance to sulfamethoxazole and chloramphenicol more frequently when obtained from TS-fed steers than from other treatments. Antibiograms and PFGE patterns suggested that AMR <it>E. coli </it>were readily transferred among steers within pens. Most M^Tisolates possessed the <it>tet</it>(B) efflux gene (58.2, 53.5, 40.8, and 50.6% of isolates from CON, T, TS, and V steers, respectively) whereas among the M^A(ampicillin-resistant) isolates, the <it>tem1</it>-like determinant was predominant (occurring in 50, 66.7, 80.3, and 100% of isolates from CON, T, TS, and V steers, respectively).</p> <p>Conclusions</p> <p>Factors other than, or in addition to subtherapeutic administration of antibiotics influence the establishment and transmission of AMR <it>E. coli </it>among feedlot cattle.</p

Longitudinal characterization of antimicrobial resistance genes in feces shed from cattle fed different subtherapeutic antibiotics

<p>Abstract</p> <p>Background</p> <p>Environmental transmission of antimicrobial-resistant bacteria and resistance gene determinants originating from livestock is affected by their persistence in agricultural-related matrices. This study investigated the effects of administering subtherapeutic concentrations of antimicrobials to beef cattle on the abundance and persistence of resistance genes within the microbial community of fecal deposits. Cattle (three pens per treatment, 10 steers per pen) were administered chlortetracycline, chlortetracycline plus sulfamethazine, tylosin, or no antimicrobials (control). Model fecal deposits (<it>n </it>= 3) were prepared by mixing fresh feces from each pen into a single composite sample. Real-time PCR was used to measure concentrations of <it>tet</it>, <it>sul </it>and <it>erm </it>resistance genes in DNA extracted from composites over 175 days of environmental exposure in the field. The microbial communities were analyzed by quantification and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified <it>16S-rRNA.</it></p> <p>Results</p> <p>The concentrations of <it>16S-rRNA </it>in feces were similar across treatments and increased by day 56, declining thereafter. DGGE profiles of <it>16S-rRNA </it>differed amongst treatments and with time, illustrating temporal shifts in microbial communities. All measured resistance gene determinants were quantifiable in feces after 175 days. Antimicrobial treatment differentially affected the abundance of certain resistance genes but generally not their persistence. In the first 56 days, concentrations of <it>tet</it>(B), <it>tet</it>(C), <it>sul1, sul2</it>, <it>erm</it>(A) tended to increase, and decline thereafter, whereas <it>tet</it>(M) and <it>tet</it>(W) gradually declined over 175 days. At day 7, the concentration of <it>erm</it>(X) was greatest in feces from cattle fed tylosin, compared to all other treatments.</p> <p>Conclusion</p> <p>The abundance of genes coding for antimicrobial resistance in bovine feces can be affected by inclusion of antibiotics in the feed. Resistance genes can persist in feces from cattle beyond 175 days with concentrations of some genes increasing with time. Management practices that accelerate DNA degradation such as frequent land application or composting of manure may reduce the extent to which bovine feces serves as a reservoir of antimicrobial resistance.</p

Institutionalizing Provider-Initiated HIV Testing and Counselling for Children: An Observational Case Study from Zambia

Background: Provider-initiated testing and counselling (PITC) is a priority strategy for increasing access for HIV-exposed children to prevention measures, and infected children to treatment and care interventions. This article examines efforts to scale-up paediatric PITC at a second-level hospital located in Zambia’s Southern Province, and serving a catchment area of 1.2 million people. Methods and Principal Findings: Our retrospective case study examined best practices and enabling factors for rapid institutionalization of PITC in Livingstone General Hospital. Methods included clinical observations, key informant interviews with programme management, and a desk review of hospital management information systems (HMIS) uptake data following the introduction of PITC. After PITC roll-out, the hospital experienced considerably higher testing uptake. In a 36-month period following PITC institutionalization, of total inpatient children eligible for PITC (n = 5074), 98.5 % of children were counselled, and 98.2 % were tested. Of children tested (n = 4983), 15.5 % were determined HIVinfected; 77.6 % of these results were determined by DNA polymerase chain reaction (PCR) testing in children under the age of 18 months. Of children identified as HIV-infected in the hospital’s inpatient and outpatient departments (n = 1342), 99.3 % were enrolled in HIV care, including initiation on co-trimoxazole prophylaxis. A number of good operational practices and enabling factors in the Livingstone General Hospital experience can inform rapid PIT

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

[EN]The role of food-producing environments in the emergence and spread of antimicrobial resistance (AMR) in EU plant-based food production, terrestrial animals (poultry, cattle and pigs) and aquaculture was assessed. Among the various sources and transmission routes identified, fertilisers of faecal origin, irrigation and surface water for plant-based food and water for aquaculture were considered of major importance. For terrestrial animal production, potential sources consist of feed, humans, water, air/dust, soil, wildlife, rodents, arthropods and equipment. Among those, evidence was found for introduction with feed and humans, for the other sources, the importance could not be assessed. Several ARB of highest priority for public health, such as carbapenem or extended-spectrum cephalosporin and/or fluoroquinolone-resistant Enterobacterales (including Salmonella enterica), fluoroquinolone-resistant Campylobacter spp., methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium and E. faecalis were identified. Among highest priority ARGs blaCTX-M, blaVIM, blaNDM, blaOXA-48-like, blaOXA-23, mcr, armA, vanA, cfr and optrA were reported. These highest priority bacteria and genes were identified in different sources, at primary and post-harvest level, particularly faeces/manure, soil and water. For all sectors, reducing the occurrence of faecal microbial contamination of fertilisers, water, feed and the production environment and minimising persistence/recycling of ARB within animal production facilities is a priority. Proper implementation of good hygiene practices, biosecurity and food safety management systems is very important. Potential AMR-specific interventions are in the early stages of development. Many data gaps relating to sources and relevance of transmission routes, diversity of ARB and ARGs, effectiveness of mitigation measures were identified. Representative epidemiological and attribution studies on AMR and its effective control in food production environments at EU level, linked to One Health and environmental initiatives, are urgently required.S

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

The role of food-producing environments in the emergence and spread of antimicrobial resistance (AMR) in EU plant-based food production, terrestrial animals (poultry, cattle and pigs) and aquaculture was assessed. Among the various sources and transmission routes identified, fertilisers of faecal origin, irrigation and surface water for plant-based food and water for aquaculture were considered of major importance. For terrestrial animal production, potential sources consist of feed, humans, water, air/dust, soil, wildlife, rodents, arthropods and equipment. Among those, evidence was found for introduction with feed and humans, for the other sources, the importance could not be assessed. Several ARB of highest priority for public health, such as carbapenem or extended-spectrum cephalosporin and/or fluoroquinolone-resistant Enterobacterales (including Salmonella enterica), fluoroquinolone-resistant Campylobacter spp., methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium and E. faecalis were identified. Among highest priority ARGs blaCTX-M, blaVIM, blaNDM, blaOXA-48-like, blaOXA-23, mcr, armA, vanA, cfr and optrA were reported. These highest priority bacteria and genes were identified in different sources, at primary and post-harvest level, particularly faeces/manure, soil and water. For all sectors, reducing the occurrence of faecal microbial contamination of fertilisers, water, feed and the production environment and minimising persistence/recycling of ARB within animal production facilities is a priority. Proper implementation of good hygiene practices, biosecurity and food safety management systems is very important. Potential AMR-specific interventions are in the early stages of development. Many data gaps relating to sources and relevance of transmission routes, diversity of ARB and ARGs, effectiveness of mitigation measures were identified. Representative epidemiological and attribution studies on AMR and its effective control in food production environments at EU level, linked to One Health and environmental initiatives, are urgently required.info:eu-repo/semantics/publishedVersio

Role played by the environment in the emergence and spread of antimicrobial resistance (AMR) through the food chain

This is the final version. Available from Wiley via the DOI in this record. The role of food-producing environments in the emergence and spread of antimicrobial resistance (AMR) in EU plant-based food production, terrestrial animals (poultry, cattle and pigs) and aquaculture was assessed. Among the various sources and transmission routes identified, fertilisers of faecal origin, irrigation and surface water for plant-based food and water for aquaculture were considered of major importance. For terrestrial animal production, potential sources consist of feed, humans, water, air/dust, soil, wildlife, rodents, arthropods and equipment. Among those, evidence was found for introduction with feed and humans, for the other sources, the importance could not be assessed. Several ARB of highest priority for public health, such as carbapenem or extended-spectrum cephalosporin and/or fluoroquinolone-resistant Enterobacterales (including Salmonella enterica), fluoroquinolone-resistant Campylobacter spp., methicillin-resistant Staphylococcus aureus and glycopeptide-resistant Enterococcus faecium and E. faecalis were identified. Among highest priority ARGs blaCTX-M, blaVIM, blaNDM, blaOXA-48-like, blaOXA-23, mcr, armA, vanA, cfr and optrA were reported. These highest priority bacteria and genes were identified in different sources, at primary and post-harvest level, particularly faeces/manure, soil and water. For all sectors, reducing the occurrence of faecal microbial contamination of fertilisers, water, feed and the production environment and minimising persistence/recycling of ARB within animal production facilities is a priority. Proper implementation of good hygiene practices, biosecurity and food safety management systems is very important. Potential AMR-specific interventions are in the early stages of development. Many data gaps relating to sources and relevance of transmission routes, diversity of ARB and ARGs, effectiveness of mitigation measures were identified. Representative epidemiological and attribution studies on AMR and its effective control in food production environments at EU level, linked to One Health and environmental initiatives, are urgently required

Polymeric Micelles in Anticancer Therapy: Targeting, Imaging and Triggered Release

Micelles are colloidal particles with a size around 5–100 nm which are currently under investigation as carriers for hydrophobic drugs in anticancer therapy. Currently, five micellar formulations for anticancer therapy are under clinical evaluation, of which Genexol-PM has been FDA approved for use in patients with breast cancer. Micelle-based drug delivery, however, can be improved in different ways. Targeting ligands can be attached to the micelles which specifically recognize and bind to receptors overexpressed in tumor cells, and chelation or incorporation of imaging moieties enables tracking micelles in vivo for biodistribution studies. Moreover, pH-, thermo-, ultrasound-, or light-sensitive block copolymers allow for controlled micelle dissociation and triggered drug release. The combination of these approaches will further improve specificity and efficacy of micelle-based drug delivery and brings the development of a ‘magic bullet’ a major step forward

An assessment of the Zimbabwe ministry of health and child welfare provider initiated HIV testing and counselling programme

Background Provider-initiated HIV testing and counselling (PITC) is widely recommended to ensure timely treatment of HIV. The Zimbabwe Ministry of Health introduced PITC in 2007. We aimed to evaluate institutional capacity to implement PITC and investigate patient and health care worker (HCW) perceptions of the PITC programme. Methods Purposive selection of health care institutions was conducted among those providing PITC. Study procedures included 1) assessment of implementation procedures and institutional capacity using a semi-structured questionnaire; 2) in-depth interviews with patients who had been offered HIV testing to explore perceptions of PITC, 3) Focus group discussions with HCW to explore views on PITC. Qualitative data was analysed according to Framework Analysis. Results Sixteen health care institutions were selected (two central, two provincial, six district hospitals; and six primary care clinics). All institutions at least offered PITC in part. The main challenges which prevented optimum implementation were shortages of staff trained in PITC, HIV rapid testing and counselling; shortages of appropriate counselling space, and, at the time of assessment, shortages of HIV test kits. Both health care workers and patients embraced PITC because they had noticed that it had saved lives through early detection and treatment of HIV. Although health care workers reported an increase in workload as a result of PITC, they felt this was offset by the reduced number of HIV-related admissions and satisfaction of working with healthier clients. Conclusion PITC has been embraced by patients and health care workers as a life-saving intervention. There is need to address shortages in material, human and structural resources to ensure optimum implementation

Antibiotic resistance genes mobility and dissemination during a long-term experiment: fifteen years of farm-soil amendment with antibiotics analyzed with high-throughput sequencing

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Les arts de la rue dans les sociétés du Sud

Le taarab est un spectacle de chansons parfois accompagné de saynètes. D'abord chanté en arabe sous l'influence égyptienne, il est devenu en ce siècle un des genres majeurs de la culture swahili de Zanzibar. La chanteuse Siti Binti Saad lui a donné une grande popularité dans la première moitié de ce siècle. Des groupes représentant les communautés culturelles de Zanzibar maintiennent, en kiswahili, la tradition arabisée du genre alors que de nouveaux groupes, sous l'influence des femmes, créent une forme plus populaire. Une concurrence s'exerce entre ces diverses variétés et contribue à la vitalité du genre. (Résumé d'auteur