Jesús T. García

Detection of methicillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene in wild small mammals in Spain

OBJECTIVES To determine the rate of Staphylococcus aureus faecal carriage in 101 wild small mammals in Spain and to characterize the isolates obtained. METHODS Faecal samples were seeded on mannitol salt agar and ORSAB plates. The presence of the resistance genes mecA, mecC and blaZ and the new blaZ allotype associated with staphylococcal cassette chromosome mec (SCCmec) XI (blaZ-SCCmecXI) was studied by PCR. S. aureus isolates were characterized by spa typing, agr typing and multilocus sequence typing. The presence of immune evasion cluster (IEC) genes and virulence genes was analysed by PCR. RESULTS S. aureus was detected in 13/101 studied faecal samples and one isolate per positive sample was further studied. Two S. aureus isolates were methicillin-resistant S. aureus (MRSA) (recovered from wood mice, Apodemus sylvaticus) and 11 were methicillin-susceptible S. aureus (MSSA). Both MRSA isolates harboured the mecC gene and the novel blaZ-SCCmecXI, were typed as spa-t1535/agrIII/ST1945(CC130)/SCCmecXI (where ST stands for sequence type and CC stands for clonal complex), carried the exfoliative toxin etd2 gene and were IEC type E. Eight different spa types were identified among the 11 MSSA isolates (five new) and six different sequence types were identified (two new). All MSSA strains were susceptible to the antibiotics tested except one blaZ-positive penicillin-resistant isolate (spa-t120/agrII/ST15). MSSA isolates were ascribed to the CCs (number of strains) CC5 (1), CC1956 (4) and singleton (6). Nine of 11 MSSA isolates carried the cna virulence gene. Only one MSSA isolate carried IEC genes (type C). CONCLUSIONS This is the first report of MRSA carrying mecC in faecal samples of wild small mammals in Spain. These resistant isolates carried genes of the IEC system, unusual in S. aureus from animals. Wild small mammals could be a reservoir of the mecC gene with important implications for public health.

Genetic evidence for multiple introduction events of raccoons (Procyon lotor) in Spain

The common raccoon (Procyon lotor) is endemic to Central and North America, although non-native populations have become established around the world. In Spain, growing evidence of the introduction of raccoons has been reported across the country in the last decade, especially in Central Spain where the largest population is thought to occur. We used mitochondrial and microsatellite DNA data to investigate the genetics of invasive raccoons in Central Spain and to infer: the number of introduction events, the number of founders and the genetic variability of the introduced populations compared to a native population. We found that at least two introduction events have occurred along the Jarama and Henares Rivers in Central Spain, which currently constitute two genetically differentiated subpopulations. In both localities the number of effective founders from a native population was estimated as 2–4 individuals. These newly founded populations have expanded and show evidence of incipient contact and reproduction between them. This may allow for an increase in the genetic variability and adaptive potential of the population(s), possibly increasing the difficulty of controlling this invasive species. Our results reveal the ability to longitudinally monitor the genetics of the raccoon range expansion and emphasize the urgent need to control the pet trade of potentially invasive species.

Modelling sandgrouse (Pterocles spp.) distributions and large-scale habitat requirements in Spain: implications for conservation

This research was jointly funded by the Direccion General de Investigacion (project CGL2008–04282/BOS) and HNV project (MARM).

Genetic consequences of interglacial isolation in a steppe bird

In response to climate changes that have occurred during Pleistocene glacial cycles, taxa associated to steppe vegetation might have followed a pattern of historical evolution in which isolation and fragmentation of populations occurred during the short interglacials and expansion events occurred during the long glacial periods, in contrast to the pattern described for temperate species. Here, we use molecular genetic data to evaluate this idea in a steppe bird with Palaearctic distribution, the little bustard (Tetrax tetrax). Overall, extremely low genetic diversity and differentiation was observed among eight little bustard populations distributed in Spain and France. Mismatch distribution analyses showed that most little bustard populations expanded during cooling periods previous to, and just after, the last interglacial period (127,000-111,000 years before present), when steppe habitats were widespread across Europe. Coalescent-based methods suggested that glacial expansions have resulted in substantial admixture in Western Europe due to the existence of different interglacial refugia. Our results are consistent with a model of evolution and genetic consequences of Pleistocene cycles with low between-population genetic differentiation as a result of short-term isolation periods during interglacials and long-term exchange during glacial periods.

Experimental evaluation of live cage-traps for black-billed magpies Pica pica management in Spain

Black-billed magpies (Pica pica) are considered as a nest predator of game and non-game birds in Europe. In rural areas of Spain magpie control is commonly used as a management tool in small game hunting estates. Cage-traps with a magpie as a decoy are the legal method most commonly used for controlling magpies in Spain although its performance has not yet been experimentally tested. We evaluated the selectivity, efficiency, and the effect of different factors on capture rate of these traps for magpie control and determine the effect of magpie removal on magpie density. Only four out of 197 captures corresponded to non-target species, which were released unharmed. Since the release of non-target captures depends on the daily checking of the trap and the trapper commitment, in order to guarantee the efficiency and selectivity of this method traps should be revised daily by full time, qualified trappers. The efficiency of this method is high during the breeding season, reducing magpie density in the area where the control is performed. Highest capture rates were obtained in the first days after cage-traps setting. Neither the gender nor the origin (local or foreign) of the decoy significantly affected the capture rate. Among male decoys, experimentally increased testosterone levels did not increase capture rates. According to our results, the tested cage-traps with a living decoy could be employed as an efficient and selective method for magpie population management in Spain, when used by full time, qualified trappers.

Detection of vancomycin-resistant Enterococcus faecalis ST6-vanB2 and E. faecium ST915-vanA in faecal samples of wild Rattus rattus in Spain

The detection of vancomycin-resistant-enterococci (VRE) among wild animals represents a worrisome public health concern. The objectives of the study were to determine the possible presence of VRE in faecal samples of wild small mammals in Spain, to characterize the vancomycin resistance mechanisms and genetic lineages of recovered isolates and to know the diversity of enterococcal species in these animals. A total of 155 faecal samples from small mammals were inoculated in Slanetz-Bartley agar supplemented or not with vancomycin (Van-SB/SB plates). The antimicrobial susceptibility profile to 12 antimicrobials and the presence of 20 antimicrobial resistance genes was analyzed. The structure of Tn1546 and the presence of gelE, cylA, asa, esp and hyl genes was studied. Multilocus-sequence-typing (MLST) technique was also performed. VRE isolates were recovered in Van-SB plates in 11 samples. Two samples contained vanB2-positive E. faecalis isolates of lineage ST6, which showed a multiresistance phenotype and harboured the virulence genes gelE and asa. One sample contained a vancomycin-resistant E. faecium isolate of the new lineage ST915, with the vanA gene included into Tn1546 (truncated with IS1542 and IS1216 elements). The vanB2 and vanA isolates were obtained from Rattus rattus. The remaining eight VRE-positive samples contained species with intrinsic vancomycin-resistance mechanisms: E. casseliflavus (n=5) and E. gallinarum (n=3). One hundred and forty-seven vancomycin-susceptible-enterococcal isolates were obtained in SB plates, and E. faecalis and E. faecium were the most frequent detected species. This is the first report of vanB2-containing enterococci in wild animals.

An improved night-lighting technique for the selective capture of sandgrouse and other steppe birds

The night-lighting technique is routinely used to catch birds. We improved this technique using a thermal infrared camera to catch steppe birds such as the sandgrouse. Target birds were located by an observer using the thermal camera, and approached and dazzled by another observer carrying a spotlight attached to a helmet and a hand-held net together with a playback noise to camouflage the footsteps of the observer. Using this improved technique, we caught on average 1.14 individuals per 3-h capture session (N = 81) and a total of 92 sandgrouse in 2007–2010 (86 pin-tailed sandgrouse Pterocles alchata and six black-bellied sandgrouse Pterocles orientalis). Capture rate and success were negatively influenced by moonlight (lowest during full moon nights). Our night-lighting technique is a highly selective and harmless method to capture sandgrouse and can be used for other small/medium-sized open-land birds or mammals.

Niche-habitat mechanisms and biotic interactions explain the coexistence and abundance of congeneric sandgrouse species

Ascertaining which niche processes allow coexistence between closely related species is of special interest in ecology. We quantified variations in the environmental niches and densities of two congeneric species, the pin-tailed and the black-bellied sandgrouse (Pterocles alchata and Pterocles orientalis) in allopatry and sympatry under similar abiotic, habitat and dispersal contexts to understand their coexistence. Using principal component analysis, we defined environmental gradients (niche dimensions) including abiotic, habitat and anthropogenic variables, and calculated niche breadth, position and overlap of both species in sympatry and allopatry. Additionally, sandgrouse density was modelled as a function of the niche dimensions and the density of the other species. We found evidence that each species occupies distinct environmental niches in sympatry and in allopatry. The black-bellied sandgrouse exploits a broader range of environmental conditions (wider niche breadth) while the pin-tailed sandgrouse reaches high densities where conditions seem to match its optimum. In sympatry, both species shift their niches to intermediate positions, indicating the importance of abiotic factors in setting coexistence areas. Environmental conditions determine regional densities of pin-tailed sandgrouse whereas biotic interactions explain the density of the black-bellied sandgrouse in areas with abiotic conditions similarly conducive for both species. Highly suitable areas for the pin-tailed sandgrouse fall beyond the upper thermal limit of the black-bellied sandgrouse, leading to niche segregation and low densities for the latter. Finally, local niche shift and expansion plus possible heterospecific aggregation allow the pin-tailed sandgrouse to thrive in a priori less favourable environments. This work provides insight into how different mechanisms allow species coexistence and how species densities vary in sympatry compared to allopatry as a result of environmental filtering and biotic interactions.

Breeding output and nest predation patterns in steppe-associated Mediterranean birds: the case of the Tawny Pipit Anthus campestris

AbstractThe main purpose of this study was to provide exhaustive and extensive data on the breeding biology of the Mediterranean Tawny Pipit Anthus campestris. Reproduction was studied within two populations nesting in shrubsteppes in central Spain. We compared breeding parameters (including hatching success, productivity, incubation, brood failures, predation rates, clutch and brood size) between study areas, and among years within each area. Our results suggest that Tawny Pipit reproduction in Spanish shrubsteppes is influenced by two main related factors: timing of breeding and nest predation. We detected seasonal declines in most breeding parameters, but a mid-season peak in productivity. Although large-sized broods were detected at the beginning of the breeding season, the recruitment of these juveniles was very low due to high predation rates on early broods. Finally, our results are compared with the scarce available data from previous breeding studies from other European Tawny Pipit populations.ZusammenfassungBrutleistung und Nestprädationsmuster bei steppegebundenen Vögeln des Mittelmeerraums: der Fall des BrachpiepersAnthus campestris Der Hauptzweck dieser Studie war es, vollständige und umfassende Daten zur Brutbiologie mediterraner Brachpieper Anthus campestris bereitzustellen. Die Fortpflanzung wurde in zwei Populationen, die in Strauchsteppe in Zentralspanien nisten, untersucht. Wir haben Brutparameter (einschließlich Schlupferfolg, Produktivität, Bebrütung, Brutverluste, Prädationsraten, Gelege- und Brutgrößen) zwischen den Untersuchungsgebieten sowie innerhalb der Untersuchungsgebiete zwischen verschienenden Jahren verglichen. Unsere Ergebnisse deuten darauf hin, dass die Fortpflanzung von Brachpiepern in spanischen Strauchsteppen von zwei Hauptfaktoren beeinflusst wird: Zeitpunkt des Brütens und Nestprädation. Wir haben ermittelt, dass die meisten Brutparameter im Verlauf der Saison abnahmen, die Produktivität jedoch in der Mitte der Saison ihren Höhepunkt erreichte. Obwohl zu Beginn der Brutsaison große Bruten erfasst wurden, waren die Rekrutierungsraten für diese Jungvögel sehr niedrig, da frühe Bruten einem hohen Prädationsrisiko ausgesetzt waren. Schließlich vergleichen wir unsere Ergebnisse mit den wenigen verfügbaren Daten aus früheren Brutstudien in anderen europäischen Brachpieperpopulationen.

Pollutants and diet influence carotenoid levels and integument coloration in nestlings of an endangered raptor

Carotenoid-based traits or ornaments, such as yellow-red integuments (feathers, beaks, legs or eye-rings) displayed by birds, play key roles in social communication by reliably advertising an individuals quality or health. In some species, these traits are displayed not only by adults but also by nestlings, and function in parent-offspring communication or sibling competition by advertising an individuals physical or physiological condition. Pollutants such as organochlorine compounds (OCs) could have disruptive effects on the coloration of these traits, thereby interfering with communication processes. Such effects have been reported in adult birds, but are still largely unknown for nestlings. Here we investigated associations between polychlorinated biphenyl (PCB) and dichlorodiphenyltrichloroethane (DDT) blood-levels, circulating carotenoid levels and the yellow-orange coloration of the cere and tarsi of wild Black Harrier Circus maurus nestlings, a scarce raptor endemic to southern Africa. As carotenoid pigments must be acquired through the diet, we also tested for an effect of dietary composition. The orangeness-purity of cere and tarsi coloration positively correlated with circulating carotenoid levels, and increased with both nestling age and the proportion of birds consumed in the diet. Circulating carotenoid levels and the orangeness-purity of colored integuments were unrelated to blood PCB levels, although the brightness of integuments (i.e. lack of pigmentation) increased with PCB levels. Nestlings with more DDT had lower levels of circulating carotenoids and reduced carotenoid-based coloration (i.e. higher hue and lower saturation, reflecting a yellow rather than orange and less intense color, respectively). Together, our results are consistent with the hypothesis that OC contaminants, in particular DDT, may disrupt carotenoid-based signaling in exposed nestlings.