ESEB Drug resistance poster session (22)

17 Aug

Sometimes the most interesting part of a symposium is the poster session. I sure think there will be some great posters about drug resistance in our symposium! The poster session takes place on Tuesday night.

I will try to write something about every poster in our poster session. But some of this will be done on the plane on my way to Lisbon.

Nicole Hawkins describes the evolution of resistance to azoles (agricultural fungicides) from standing genetic variation

Nicole Hawkins writes: “For my poster, I will be presenting an example of resistance in agriculture, in a fungal plant pathogen, with an interesting resistance mechanism in which a second paralogue of the target site, having almost been lost from the population, re-emerged under selection by fungicides. (A nice example of selection from standing variation…)”

Yue Wu studies evolutionary escape in fluctuating environments

Yue Wu proposes a model which uses reaction norms to describe the fitness of bacterial strains, depending on genotype (sensitive and resistant) and the environment (drug concentration). Using this model, she studies evolutionary escape in fluctuating environments.

Yue Wu works at the University of New South Wales in Australia.

Nina Wale looks at mixed malaria infections

Malaria infections are often mixed, i.e., containing both drug resistant and drug sensitive strains. Aggressive malaria treatment with high doses of drugs may prevent the de novo evolution of resistance, but such aggressive treatment may not be optimal for mixed infections, because aggressive treatment can make it more likely that already present resistant strains outcompete the wildtype. Nina Wale from Penn State looks at whether reduced nutrient availability can prevent the resistant strains from growing to high numbers and causing disease. She writes that “Compounds that alter the host environment represent a novel, potentially ‘evolution proof’ class of drugs that could be used in combination with existing drugs to slow the evolution of drug resistance.”

Maya Groner talks about drug resistance in sea lice

Sea lice are a problem on salmon farms. Treatment is with chemicals, but the sea lice evolve to become resistant. Maya Groner models the evolution of resistance in sea lice, and studies how the rate of evolution depends on the genetic architecture (one or many loci) and on treatment and temperature. Maya Groner is at the University of Prince Edward Island in Canada.

George Shireff studies resistant HIV strains in the Swiss epidemic

It is well known that HIV can evolve to become drug resistant during treatment. It is also known that drug-resistant HIV strains can be transmitted to other people. However, it is unclear whether transmission of the resistant strains is as likely as transmission of the wildtype strains. George Shireff from the ETH in Zurich uses data from the Swiss cohort study and finds that resistant strains are much less likely to be transmitted.

Sarah Cobey studies balancing selection for resistance

Many of us are infected, asymptomatically, with Streptococcus pneumoniae or pneumococcus. Antibiotic resistant strains have appeared in the last two decades and now co-exist with susceptible strains. Sarah Cobey studies how immune-mediated competition may explain this coexistence.
Sarah Cobey is one of the organizers of the drug resistance symposium. She recently started her own group at the University of Chicago.

Victoria Furio on intrinsic resistance in Pseudomonas species

Victoria Furio studies how low-level or intrinsic resistance varies between species of Pseudomonas. She finds that differences in intrinsic resistance are substantial and that these difference are likely due to historic selection pressures. She also finds that the differences in intrinsic resistance play a role in how the different species can evolve to become completely resistant to clinical doses of antibiotics.
Victoria Furio is in Oxford and works with Craig MacLean (one of our invited speakers).

Alexey Mikaberidze on the spatial dynamics of fungicide resistance

Alexey Mikaberidze studies the invasion, persistence and spread of fungicide resistance in agricultural plant populations. He is especially interested in the different spatial scales on which the host, the parasite and the chemical control interact.

Alexey Mikaberidze works at the ETH in Zurich.

Claudia Seiler looks at heavy metals and drug resistance

Heavy metals are relevant for drug resistance because bacteria that become resistant to heavy metals are often also resistant to antibiotics. Bacteria, antibiotics and heavy metals meet each other in aquatic environments. By studying at Pseudomonas and Aeromonas strains from the Western Bug River (nice name for a river!) Claudia Seiler found that heavy metals in the environment increase the risk of antibiotic resistance.

Alexander Nijevitch studies Cag+ and Cag- Heliobacter pylori strains

This is a study on treatment in 41 young patients who are infected with H. pylori. Some of the H. pylori strains are Cag-, that is, they have lost the CagA pathogenicity island. Treatment with antibiotics was successful in 33 patients, but not successful in the remaining 8 patients. Compared to the 33 successful cases, the 8 patients with unsuccessful treatment were more likely to be infected with Cag- strains.

Uri Obolski models the effect of stress-induced mutation for drug resistance

Uri Oboski from Tel Aviv University looks at the effect of stress-induced mutation or stress-induced horizontal gene transfer. He finds that, if stress-induced mutation is relevant then treatment with multiple drugs at the same time may not be a good strategy.

Jianhua Zhang studies the evolution of azole resistance in a mold

Aspergillus fumigatus is a mold that can infect the human lung. 5% of the strains in The Netherlands are resistant to azoles, which are normally used to treat A. fumigatus infections. Most of the resistant strains have an insertion in one gene and a point mutation in another gene. Jianhua Zhang uses experimental evolution to determine under which conditions such resistance is likely to evolve. Jianhua Zhang is at the University of Wageningen (The Netherlands)

Melanie Ghoul on the evolutionary loss of bacteriocin production

Lungs of CF patients are often colonized by Pseudomonas aeruginosa, and once there, the infection usually lasts for decades. P. aeruginosa produce bacteriocins which help it to colonize new environments. However, during the long infection time of a patient, P. aeruginosa may lose its ability to produce bacteriocins and its resistance to bacteriocins. Melanie Ghoul from Oxford studies patient derived and non-patient derived strains to study the evolutionary loss of bacteriocin production and resistance.

Camilo Barbosa on different resistance mechanisms in P. aeruginosa

Pseudomonas aeruginosa can grow in very diverse environments, such as the roots of plants and the lungs of humans. P. aeruginosa can acquire resistance to treatment in many different ways, for example, through the use of efflux pumps or the forming of biofilms. Camilo Barbosa from the University of Kiel (Germany) uses experimental evolution to study the importance of different resistance mechanisms.

Frédéric Chevalier confirms the locus of oxamniquine resistance

Frédéric Chevalier is interested in the genetic basis of oxamniquine resistance in the parasitic fluke Schistosoma mansoni. Using a novel technique, termed extreme QTL, he confirmed the location of the oxamniquine resistance locus. The method starts with a cross between a resistant and a susceptible strain, and a subsequent cross between the F1 progeny. The F2s where used to infect hamsters and half of the hamsters were treated with the drug oxamniquine. Exomes from F2 flukes from treated and untreated hamsters were sequenced to high depth.

Frédéric Chevalier on sequencing exomes of larval stages of schistosomes

Schistosomes are parasitic flukes. The adults are usually not available for analysis, and the larvae are too small to do traditional sequencing of the entire genome. Frédéric Chevalier from the Texas Biomedical Research Institute describes a method to sequence accurately and economically the exome of the larval stages.

Martina Bradic on the genetic basis of drug resistance in Trichomonas vaginalis

Trichomonas vaginalis is the most widespread non-viral sexually transmitted pathogen in the world. Around 10% of isloates are resistant to common drugs (5-nitroimidazole). The genetic basis of resistance is unknown. Using double digest Restriction-Site Associated DNA (ddRAD) sequencing Martina Bradic is trying to uncover the genetic basis of drug resistance.
Martina Bradic works at NYU.

Joana Serra on the effect of low levels of antibiotics

Low levels of antibiotics may stimulate growth of bacteria and select for high level drug resistance. Such low levels may be present in nature or human body compartments during treatment. Joana Serra looks at the effect of low lecels of antibiotics on Stenotrophomonas maltophilia.
Joana Serra works in the Center for Biodiversity, Functional & Integrative Genomics in Portugal.

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