Quantifying Rates of Evolutionary Adaptation in Response to Ocean Acidification

The global acidification of the earth's oceans is predicted to impact biodiversity via physiological effects impacting growth, survival, reproduction, and immunology, leading to changes in species abundances and global distributions. However, the degree to which these changes will play out critically depends on the evolutionary rate at which populations will respond to natural selection imposed by ocean acidification, which remains largely unquantified. Here we measure the potential for an evolutionary response to ocean acidification in larval development rate in two coastal invertebrates using a full-factorial breeding design. We show that the sea urchin species Strongylocentrotus franciscanus has vastly greater levels of phenotypic and genetic variation for larval size in future CO2 conditions compared to the mussel species Mytilus trossulus. Using these measures we demonstrate that S. franciscanus may have faster evolutionary responses within 50 years of the onset of predicted year-2100 CO2 conditions despite having lower population turnover rates. Our comparisons suggest that information on genetic variation, phenotypic variation, and key demographic parameters, may lend valuable insight into relative evolutionary potentials across a large number of species

Recovery of a functional class 2 integron from an Escherichia coli strain mediating a urinary tract infection

A class 2 integron was found in an Escherichia coli isolate mediating a urinary tract infection. Unlike other class 2 integrons from pathogens, the encoded IntI2 protein was functional. The integron possessed a dfrA14 cassette, and a second novel cassette in which a lipoprotein signal peptidase gene is predicted. Copyright © 2008, American Society for Microbiology. All Rights Reserved

Mytilid mussels: global habitat engineers in coastal sediments

International audienceDense beds of mussels of the family Mytilidae occur worldwide on soft-bottoms in cold and warm temperate coastal waters and have usually been considered hot spots of biodiversity. We examined intertidal mussel beds at four distant locations around the globe with the same sampling method, to find out whether this “hot spot” designation holds universally. We studied species assemblages within the matrices of byssally interconnected mussels engineered by in the North Sea, by mixed and at the southern Chilean coast, by in the Yellow Sea and by at the coast of southern Australia. In all cases, species assemblages inside mussel beds were significantly different from those outside with many species being restricted to one habitat type. However, species richness and diversity were not generally higher in mussel beds than in ambient sediments without mussels. In the North Sea () and at the Chilean coast (, ), mussel beds have markedly higher species numbers and diversities than surrounding sediments, but this was not the case for mussel beds in Australia () and the Yellow Sea () where numbers of associated species were only slightly higher and somewhat lower than in adjacent sediments, respectively. In conclusion, although soft bottom mytilid mussels generally enhance habitat heterogeneity and species diversity at the ecosystem level, mussel beds themselves are not universal centres of biodiversity, but the effects on associated species are site specific

Dissemination of multiple drug resistance genes by class 1 integrons in Klebsiella pneumoniae isolates from four countries: A comparative study

A comparative genetic analysis of 42 clinical Klebsiella pneumoniae isolates, resistant to two or more antibiotics belonging to the broad-spectrum β-lactam group, sourced from Sydney, Australia, and three South American countries is presented. The study focuses on the genetic contexts of class 1 integrons, mobilizable genetic elements best known for their role in the rapid evolution of antibiotic resistance among Gram-negative pathogens. It was found that the class 1 integrons in this cohort were located in a number of different genetic contexts with clear regional differences. In Sydney, IS26-associated Tn21-like transposons on IncL/M plasmids contribute greatly to the dispersal of integron-associated multiple-drug-resistant (MDR) loci. In contrast, in the South American countries, Tn1696-like transposons on an IncA/C plasmid(s) appeared to be disseminating a characteristic MDR region. A range of mobile genetic elements is clearly being recruited by clinically important mobile class 1 integrons, and these elements appear to be becoming more common with time. This in turn is driving the evolution of complex and laterally mobile MDR units and may further complicate antibiotic therapy. Copyright © 2011, American Society for Microbiology. All Rights Reserved

Emergence of KPC-producing Klebsiella pneumoniae in Uruguay: infection control and molecular characterization

We describe the first outbreak of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP), the infection control measures adopted and the shift in resistance patterns of isolates during antibiotic treatment. The ST258 KPC-KP strain exhibited a multiresistant antibiotic phenotype including co-resistance to gentamycin, colistin and tigecycline intermediate susceptibility. Isolates before and after treatment had different behaviour concerning their antibiotic susceptibility and the population analysis profile study. A progressive increase in the aminoglycosides (acquiring amicacin resistance) and β-lactam MICs, and a decreased susceptibility to fosfomycin was observed throughout the administration of combined antimicrobial regimens including meropenem. A high meropenem resistance KPC-KP homogeneous population (MIC 256 Jg/mL), could arise from the meropenem heterogeneous low-level resistance KPC-KP population (MIC 8 Jg/mL), by the selective pressure of the prolonged meropenem therapy. The kpc gene was inserted in a Tn4401 isoform a, and no transconjugants were detected. The core measures adopted were successful to prevent evolution towards resistance dissemination

Resistance to Ceftriaxone and Azithromycin in Neisseria gonorrhoeae Isolates From 7 Countries of South America and the Caribbean: 2010-2011

Fil: Thakur, Sidharath Dev. Department of Microbiology, College of Medicine; Estados Unidos.Fil: Araya, Pamela. Instituto de Salud Publica de Chile, Santiago; Chile.Fil: Borthagaray, Graciela. Faculdad de Quimica, Universidad de la Republica, Montevideo; Uruguay.Fil: Galarza, Patricia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Hernandez, Alina Llop. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Medicina Tropical; Argentina.Fil: Payares, Daisy. Instituto Nacional Higiene "Rafael Rangel", Caracas; Venezuela.Fil: Sanabria Cruz, Olga Marina. Instituto National de Salud, Bogota; Colombia.Fil: Carvallo, Maria Elena Trigoso. Centro Departmental de Vigilancia Information y Referencia, CDVIR La Paz; Bolivia.Fil: Corredor, Aura Helena. Vaccine and infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatchewan; Canada.Fil: Dillon, Jo-Anne R. Vaccine and infectious Disease Organization-International Vaccine Center, University of Saskatchewan, Saskatchewan; Canada.Seven countries in Latin America and the Caribbean report on (2010 and 2011) the susceptibility of 2235 isolates of Neisseria gonorrhoeae to 6 antibiotics. Thirteen isolates had ceftriaxone minimum inhibitory concentrations (MICs) of 0.125 to ≥ 0.25 mg/L. The percentage of resistant isolates to the following antibiotics was: azithromycin, 1.0% to 1.7%; ciprofloxacin, 42.1% to 36.2%; penicillin, 31% to 35%; tetracycline, 21.8% to 22.6%