Correlation Between Antimicrobial Resistance, Virulence Determinants and Biofilm Formation Ability Among Extraintestinal Pathogenic Escherichia coli Strains Isolated in Catalonia, Spain.

Escherichia coli is a well-characterized bacterium highly prevalent in the human intestinal tract and the cause of many important infections. The aim of this study was to characterize 376 extraintestinal pathogenic E. coli strains collected from four hospitals in Catalonia (Spain) between 2016 and 2017 in terms of antimicrobial resistance, siderophore production, phylogroup classification, and the presence of selected virulence and antimicrobial resistance genes. In addition, the association between these characteristics and the ability to form biofilms was also analyzed. The strains studied were classified into four groups according to their biofilm formation ability: non-biofilm formers (15.7%), weak (23.1%), moderate (35.6%), and strong biofilm formers (25.6%). The strains were highly resistant to ciprofloxacin (48.7%), trimethoprim-sulfamethoxazole (47.9%), and ampicillin (38%), showing a correlation between higher resistance to ciprofloxacin and lower biofilm production. Seventy-three strains (19.4%) were ESBL-producers. However, no relationship between the presence of ESBL and biofilm formation was found. The virulence factor genes fimH (92%), pgaA (84.6%), and irp1 (77.1%) were the most prevalent in all the studied strains. A statistically significant correlation was found between biofilm formation and the presence of iroN, papA, fimH, sfa, cnf, hlyA, iutA, and colibactin-encoding genes clbA, clbB, clbN, and clbQ. Interestingly, a high prevalence of colibactin-encoding genes (19.9%) was observed. Colibactin is a virulence factor, which interferes with the eukaryotic cell cycle and has been associated with colorectal cancer in humans. Most colibactin-encoding E. coli isolates belonged to phylogroup B2, exhibited low antimicrobial resistance but moderate or high biofilm-forming ability, and were significantly associated with most of the virulence factor genes tested. Additionally, the analysis of their clonal relatedness by PFGE showed 48 different clusters, indicating a high clonal diversity among the colibactin-positive strains. Several studies have correlated the pathogenicity of E. coli and the presence of virulence factor genes; however, colibactin and its relationship to biofilm formation have been scarcely investigated. The increasing prevalence of colibactin in E. coli and other Enterobacteriaceae and the recently described correlation with biofilm formation, makes colibactin a promising therapeutic target to prevent biofilm formation and its associated adverse effects.

Reduction of inflammatory pain in female rats after NR2B NMDA cortical antagonism / Reducción del dolor inflamatorio en ratas hembras tras el antagonismo cortical de NR2B NMDA

Studies have shown that N-methyl-D-aspartate (NMDA) receptors play a critical role in pain processing at different levels of the central nervous system. In this study, we used female adult Wistar rats to examine the effects of antagonizing the NR2B subunit of the NMDA receptor in phasic and tonic pain processes. All the rats underwent stereotaxic surgery for cortical cannula implantation and after at least one week of recovery, rats performed behavioral tests. For evaluating the effects of drugs on motor coordination rats were tested in the rotarod apparatus. Moreover, rats were evaluated in the paw withdrawal latency (PWL) to a noxious thermal stimulus. Furthermore, rats were tested in the formalinpain test. Rats that received the NR2B antagonist Ro 25-6981 before and after formalin injection showed significantly reduced pain responses in the formalin test, as compared with female control rats (p<0.05). In contrast, no differences among groups were found in the phasic pain test (Hargreaves) and the rotarod test. Taken together, these results suggest that cortical antagonism of the NR2B subunit of NMDA receptors is able to reduce inflammatory pain levels not only before, but after the formalin injection in females at different phases of the estrous cycle (AU)

Estudios han demostrado que los receptores de N-methyl-D-aspartato (NMDA) participan en el procesamiento del dolor en diferentes niveles del SNC. Este estudio empleó ratas hembras adultas Wistar para evaluar el antagonismo de la subunidad NR2B de NMDA en los procesos de dolor fásico y tónico. Se implantaron cánulas corticalmente con la cirugía estereotáxica y tras una semana de recuperación se realizaron pruebas conductuales. Se evaluaron los efectos del fármaco en la coordinación motora en el aparato de barra giratoria. Además, las ratas realizaron la prueba de latencia de retirada de la pata a un estímulo termal nocivo. Posteriormente, las ratas realizaron la prueba de formalina. Las ratas hembras que recibieron el antagonista de NR2B, Ro 25-6981, antes y después de la inyección de formalina denotaron respuestas de dolor significativamente menores en comparación con los controles (p<0.05). En contraste, no se encontraron diferencias significativas en la prueba de dolor fásico (Hargreaves) y la prueba de barra giratoria. En conjunto, estos resultados sugieren que el antagonismo cortical de la subunidad NR2B de los receptores NMDA es capaz de reducir los niveles de dolor inflamatorio, antes y después de la inyección de formalina en las distintas fases del ciclo estral (AU)

Reduction of inflammatory pain in female rats after NR2B NMDA cortical antagonism.

Studies have shown that N-methyl-D-aspartate (NMDA) receptors play a critical role in pain processing at different levels of the central nervous system. In this study, we used female adult Wistar rats to examine the effects of antagonizing the NR2B subunit of the NMDA receptor in phasic and tonic pain processes. All the rats underwent stereotaxic surgery for cortical cannula implantation and after at least one week of recovery, rats performed behavioral tests. For evaluating the effects of drugs on motor coordination rats were tested in the rotarod apparatus. Moreover, rats were evaluated in the paw withdrawal latency (PWL) to a noxious thermal stimulus. Furthermore, rats were tested in the formalin-pain test. Rats that received the NR2B antagonist Ro 25-6981 before and after formalin injection showed significantly reduced pain responses in the formalin test, as compared with female control rats (p<0.05). In contrast, no differences among groups were found in the phasic pain test (Hargreaves) and the rotarod test. Taken together, these results suggest that cortical antagonism of the NR2B subunit of NMDA receptors is able to reduce inflammatory pain levels not only before, but after the formalin injection in females at different phases of the estrous cycle.