ABSTRACT
The bumblebee, Bombus terrestris, is an important pollinator commercially used on a global scale. The exported subspecies B. t. terrestris has colonised diverse environments, in some cases displacing wild pollinators to the verge of local extinction. In this sense, the native Iberian subspecies B. t. lusitanicus may be threatened by the subspecies B. t. terrestris, naturally distributed from the Pyrenees to Central Europe but also observed in southern Spain due to escapes from commercial nests. Mitochondrial genomes have a low recombination rate and a small effective population size owing to their maternal inheritance, thus providing an accurate approach to study hybridisation events between populations. Therefore, we present the sequences of the mitogenomes of both subspecies as a molecular framework to select suitable markers to detect possible introgression events between them. We used metagenomics to obtain approximately 17 kbp of the mitogenome from both subspecies. Their mitogenomes differed in 358 bp (excluding the AT-rich region). Four mitogenomic fragments were selected to be tested as subspecific diagnostic markers. A RFLP detected in the gene nad2 (NADH dehydrogenase subunit 2) has proven to be an efficient, quick and cost-effective tool to assess the dispersion of the non-endemic subspecies into Iberian native populations. Subspecific haplotypes were observed in both morphological subspecies, suggesting introgression events in the northern natural contact area and in the new human-mediated contact area in the south of the Iberian Peninsula.
Subject(s)
Bees/genetics , Genetics, Population , Genome, Mitochondrial , Animals , Haplotypes , Polymorphism, Restriction Fragment Length , SpainABSTRACT
En el presente estudio, que tuvo por objeto analizar los mecanismos involucrados en la resistencia a carbapenemes, se incluyeron 129 aislamientos de Pseudomonas aeruginosa recuperados durante el año 2006 en el Hospital "Eva Perón" de la Provincia de Buenos Aires. La caracterización fenotípica y genotípica de la resistencia permitió reconocer la presencia de metalo-beta-lactamasas (MBL) en el 14% de esos aislamientos. En todos ellos se identificó la presencia de la enzima IMP-13; sin embargo, algunos aislamientos resultaron sensibles a carbapenemes de acuerdo con los puntos de corte establecidos por el CLSI e incluso con las sugerencias de la Subcomisión de Antimicrobianos de SADEBAC, AAM. El ensayo de detección fenotípica de MBL de sinergia con doble disco resultó útil en este estudio. Sólo aquellos aislamientos productores de IMP-13 que a su vez presentaron alteraciones en las proteínas de membrana externa resultaron completamente resistentes a imipenem. Los aislamientos productores de MBL correspondieron a varios tipos clonales, lo cual sugiere no sólo la diseminación de una cepa resistente, sino también la diseminación horizontal de este mecanismo de resistencia entre clones diferentes.
From 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital "Eva Perón"), 14% produced IMP-13. Although 18 isolates were metallo-beta-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-beta-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.
Subject(s)
beta-Lactam Resistance , Cross Infection/microbiology , Drug Resistance, Multiple, Bacterial , Imipenem/pharmacology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/isolation & purification , Argentina/epidemiology , Bacterial Outer Membrane Proteins/genetics , Bacterial Proteins/analysis , Bacterial Proteins/genetics , Ceftazidime/pharmacology , Cross Infection/epidemiology , Genotype , Microbial Sensitivity Tests , Phenotype , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/genetics , Sequence Analysis, DNA , beta-Lactamases/analysis , beta-Lactamases/geneticsABSTRACT
From 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital "Eva Perón"), 14% produced IMP-13. Although 18 isolates were metallo-beta-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-beta-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.
