Antimicrobial resistance and the environment : assessment of advances, gaps and recommendations for agriculture, aquaculture and pharmaceutical manufacturing

A roundtable discussion held at the fourth International Symposium on the Environmental Dimension of Antibiotic Resistance (EDAR4) considered key issues concerning the impact on the environment of antibiotic use in agriculture and aquaculture, and emissions from antibiotic manufacturing. The critical control points for reducing emissions of antibiotics from agriculture are antibiotic stewardship and the pre-treatment of manure and sludge to abate antibiotic-resistant bacteria. Antibiotics are sometimes added to fish and shellfish production sites via the feed, representing a direct route of contamination of the aquatic environment. Vaccination reduces the need for antibiotic use in high value (e.g. salmon) production systems. Consumer and regulatory pressure will over time contribute to reducing the emission of very high concentrations of antibiotics from manufacturing. Research priorities include the development of technologies, practices and incentives that will allow effective reduction in antibiotic use, together with evidence-based standards for antibiotic residues in effluents. All relevant stakeholders need to be aware of the threat of antimicrobial resistance and apply best practice in agriculture, aquaculture and pharmaceutical manufacturing in order to mitigate antibiotic resistance development. Research and policy development on antimicrobial resistance mitigation must be cognizant of the varied challenges facing high and low income countries.Peer reviewe

Interpersonal violence against children in sport in the Netherlands and Belgium

The current article reports on the first large-scale prevalence study on interpersonal violence against children in sport in the Netherlands and Belgium. Using a dedicated online questionnaire, over 4,000 adults prescreened on having participated in organized sport before the age of 18 were surveyed with respect to their experiences with childhood psychological, physical, and sexual violence while playing sports. Being the first of its kind in the Netherlands and Belgium, our study has a sufficiently large sample taken from the general population, with a balanced gender ratio and wide variety in socio-demographic characteristics. The survey showed that 38% of all respondents reported experiences with psychological violence, 11% with physical violence, and 14% with sexual violence. Ethnic minority, lesbian/gay/bisexual (LGB) and disabled athletes, and those competing at the international level report significantly more experiences of interpersonal violence in sport. The results are consistent with rates obtained outside sport, underscoring the need for more research on interventions and systematic follow-ups, to minimize these negative experiences in youth sport

Population structure and spatio-temporal transmission dynamics of Plasmodium vivax after radical cure treatment in a rural village of the Peruvian Amazon.

BACKGROUND: Despite the large burden of Plasmodium vivax, little is known about its transmission dynamics. This study explored the population structure and spatio-temporal dynamics of P. vivax recurrent infections after radical cure in a two-year cohort study carried out in a rural community of the Peruvian Amazon. METHODS: A total of 37 P. vivax participants recruited in San Carlos community (Peru) between April and December 2008 were treated radically with chloroquine and primaquine and followed up monthly for two years with systematic blood sampling. All samples were screened for malaria parasites and subsequently all P. vivax infections genotyped using 15 microsatellites. Parasite population structure and dynamics were determined by computing different genetic indices and using spatio-temporal statistics. RESULTS: After radical cure, 76% of the study participants experienced one or more recurrent P. vivax infections, most of them sub-patent and asymptomatic. The parasite population displayed limited genetic diversity (He = 0.49) and clonal structure, with most infections (84%) being monoclonal. Spatio-temporal clusters of specific haplotypes were found throughout the study and persistence of highly frequent haplotypes were observed over several months within the same participants/households. CONCLUSIONS: In San Carlos community, P. vivax recurrences were commonly observed after radical treatment, and characterized by asymptomatic, sub-patent and clustered infections (within and between individuals from a few neighbouring households). Moreover low genetic diversity as well as parasite inbreeding are likely to define a clonal parasite population which has important implications on the malaria epidemiology of the study area

Human Plasmodium knowlesi infection in Ranong province, southwestern border of Thailand

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium knowlesi</it>, a simian malaria parasite, has been reported in humans in many Southeast Asian countries. In Thailand, most of the limited numbers of cases reported so far were from areas near neighbouring countries, including Myanmar.</p> <p>Methods</p> <p>Blood samples collected from 171 Thai and 248 Myanmese patients attending a malaria clinic in Ranong province, Thailand, located near the Myanmar border were investigated for <it>P. knowlesi </it>using nested PCR assays. Positive samples were also investigated by PCR for <it>Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae </it>and <it>Plasmodium ovale</it>, and were confirmed by sequencing the gene encoding the circumsporozoite protein (<it>csp</it>).</p> <p>Results</p> <p>Two samples, one obtained from a Thai and the other a Myanmese, were positive for <it>P. knowlesi </it>only. Nucleotide sequences of the <it>csp </it>gene derived from these two patients were identical and phylogenetically indistinguishable from other <it>P. knowlesi </it>sequences derived from monkeys and humans. Both patients worked in Koh Song, located in the Kawthoung district of Myanmar, which borders Thailand.</p> <p>Conclusion</p> <p>This study indicates that transmission of <it>P. knowlesi </it>is occurring in the Ranong province of Thailand or the Kawthoung district of Myanmar. Further studies are required to assess the incidence of knowlesi malaria and whether macaques in these areas are the source of the infections.</p

Multiplicity and Diversity of Plasmodium vivax Infections in a Highly Endemic Region in Papua New Guinea

Plasmodium vivax is highly endemic in the lowlands of Papua New Guinea and accounts for a large proportion of the malaria cases in children less than 5 years of age. We collected 2117 blood samples at 2-monthly intervals from a cohort of 268 children aged 1 to 4.5 years and estimated the diversity and multiplicity of P. vivax infection. All P. vivax clones were genotyped using the merozoite surface protein 1 F3 fragment (msp1F3) and the microsatellite MS16 as molecular markers. High diversity was observed with msp1F3 (HE = 88.1%) and MS16 (HE = 97.8%). Of the 1162 P. vivax positive samples, 74% harbored multi-clone infections with a mean multiplicity of 2.7 (IQR = 1–3). The multiplicity of P. vivax infection increased slightly with age (P = 0.02), with the strongest increase in very young children. Intensified efforts to control malaria can benefit from knowledge of the diversity and MOI both for assessing the endemic situation and monitoring the effects of interventions

A New Single-Step PCR Assay for the Detection of the Zoonotic Malaria Parasite Plasmodium knowlesi

Recent studies in Southeast Asia have demonstrated substantial zoonotic transmission of Plasmodium knowlesi to humans. Microscopically, P. knowlesi exhibits several stage-dependent morphological similarities to P. malariae and P. falciparum. These similarities often lead to misdiagnosis of P. knowlesi as either P. malariae or P. falciparum and PCR-based molecular diagnostic tests are required to accurately detect P. knowlesi in humans. The most commonly used PCR test has been found to give false positive results, especially with a proportion of P. vivax isolates. To address the need for more sensitive and specific diagnostic tests for the accurate diagnosis of P. knowlesi, we report development of a new single-step PCR assay that uses novel genomic targets to accurately detect this infection.We have developed a bioinformatics approach to search the available malaria parasite genome database for the identification of suitable DNA sequences relevant for molecular diagnostic tests. Using this approach, we have identified multi-copy DNA sequences distributed in the P. knowlesi genome. We designed and tested several novel primers specific to new target sequences in a single-tube, non-nested PCR assay and identified one set of primers that accurately detects P. knowlesi. We show that this primer set has 100% specificity for the detection of P. knowlesi using three different strains (Nuri, H, and Hackeri), and one human case of malaria caused by P. knowlesi. This test did not show cross reactivity with any of the four human malaria parasite species including 11 different strains of P. vivax as well as 5 additional species of simian malaria parasites.The new PCR assay based on novel P. knowlesi genomic sequence targets was able to accurately detect P. knowlesi. Additional laboratory and field-based testing of this assay will be necessary to further validate its utility for clinical diagnosis of P. knowlesi

Optimising the future Belgian offshore wind farm monitoring programme

Six years of monitoring triggered a reflection on how to best continue with the monitoring programme. The basic monitoring has to be rationalised at the level of the likelihood of impact detection, the meaningfulness of impact size and representativeness of the findings. Targeted monitoring should continue to disentangle processes behind the observed impact, for instance the overarching artificial reef effect created by wind farms. The major challenge however remains to achieve a reliable assessment of the cumulative impacts. Continuing consultation and collaboration within the Belgian offshore wind farm monitoring team and with foreign marine scientists and managers will ensure an optimisation of the future monitoring programme

Infection prevention and control interventions in the first outbreak of methicillin-resistant Staphylococcus aureus infections in an equine hospital in Sweden

<p>Abstract</p> <p>Background</p> <p>The first outbreak of methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) infection in horses in Sweden occurred in 2008 at the University Animal Hospital and highlighted the need for improved infection prevention and control. The present study describes interventions and infection prevention control in an equine hospital setting July 2008 - April 2010.</p> <p>Method</p> <p>This descriptive study of interventions is based on examination of policy documents, medical records, notes from meetings and cost estimates. MRSA cases were identified through clinical sampling and telephone enquiries about horses post-surgery. Prospective sampling in the hospital environment with culture for MRSA and genotyping of isolates by <it>spa</it>-typing and pulsed-field gel electrophoresis (PFGE) were performed.</p> <p>Results</p> <p>Interventions focused on interruption of indirect contact spread of MRSA between horses via staff and equipment and included: Temporary suspension of elective surgery; and identification and isolation of MRSA-infected horses; collaboration was initiated between authorities in animal and human public health, human medicine infection control and the veterinary hospital; extensive cleaning and disinfection was performed; basic hygiene and cleaning policies, staff training, equipment modification and interior renovation were implemented over seven months.</p> <p>Ten (11%) of 92 surfaces sampled between July 2008 and April 2010 tested positive for MRSA <it>spa</it>-type 011, seven of which were from the first of nine sampling occasions. PFGE typing showed the isolates to be the outbreak strain (9 of 10) or a closely related strain. Two new cases of MRSA infection occurred 14 and 19 months later, but had no proven connections to the outbreak cases.</p> <p>Conclusions</p> <p>Collaboration between relevant authorities and the veterinary hospital and formation of an infection control committee with an executive working group were required to move the intervention process forward. Support from hospital management and the dedication of staff were essential for the development and implementation of new, improved routines. Demonstration of the outbreak strain in the environment was useful for interventions such as improvement of cleaning routines and interior design, and increased compliance with basic hygienic precautions. The interventions led to a reduction in MRSA-positive samples and the outbreak was considered curbed as no new cases occurred for over a year.</p

True versus Apparent Malaria Infection Prevalence: The Contribution of a Bayesian Approach

AIMS: To present a new approach for estimating the "true prevalence" of malaria and apply it to datasets from Peru, Vietnam, and Cambodia. METHODS: Bayesian models were developed for estimating both the malaria prevalence using different diagnostic tests (microscopy, PCR & ELISA), without the need of a gold standard, and the tests' characteristics. Several sources of information, i.e. data, expert opinions and other sources of knowledge can be integrated into the model. This approach resulting in an optimal and harmonized estimate of malaria infection prevalence, with no conflict between the different sources of information, was tested on data from Peru, Vietnam and Cambodia. RESULTS: Malaria sero-prevalence was relatively low in all sites, with ELISA showing the highest estimates. The sensitivity of microscopy and ELISA were statistically lower in Vietnam than in the other sites. Similarly, the specificities of microscopy, ELISA and PCR were significantly lower in Vietnam than in the other sites. In Vietnam and Peru, microscopy was closer to the "true" estimate than the other 2 tests while as expected ELISA, with its lower specificity, usually overestimated the prevalence. CONCLUSIONS: Bayesian methods are useful for analyzing prevalence results when no gold standard diagnostic test is available. Though some results are expected, e.g. PCR more sensitive than microscopy, a standardized and context-independent quantification of the diagnostic tests' characteristics (sensitivity and specificity) and the underlying malaria prevalence may be useful for comparing different sites. Indeed, the use of a single diagnostic technique could strongly bias the prevalence estimation. This limitation can be circumvented by using a Bayesian framework taking into account the imperfect characteristics of the currently available diagnostic tests. As discussed in the paper, this approach may further support global malaria burden estimation initiatives