Acinetobacter Baumannii Multiresistente y su Relación con la Producción de Biopelículas

Resumen Introducción: Acinetobacter baumannii es la bacteria Gram negativa asociada a infecciones intrahospitalarias por su gran facilidad de supervivencia en condiciones adversas y el desarrollo de multirresistencia a diversos antimicrobianos. Durante años se han registrado brotes hospitalarios en diferentes países asociados a esta bacteria, lo que aumentó el interés de estudio de las biopelículas y los genes involucrados en su producción, debido a que se demostró una asociación a la resistencia antibiótica. Objetivos: Establecer relacion entre la multirresistencis a los diferentes antibioticos y la formacion de biopeliculas en aislamientos de Acinetobacter baumannii. Métodos: Se estudió cepas de Acinetobacter baumannii utilizando reacción en cadena de la polimerasa (PCR) en tiempo real para la detección de genes bap, csuE, ompA, oxa-51 de 191 muestras, de igual manera se realizó la cuantificación de la biopelícula formada siguiendo la técnica descrita por Badmasti y Azizi. Resultados: Se realizó este estudio sobre 191 cepas de Acinetobacter baumannii provenientes de dos centros hospitalarios para la identificación de genes asociados a las biopelículas y posterior cuantificación de acuerdo a la técnica descrita por Badmasti y Azizi. Demostrando una asociación entre las biopelículas y la resistencia bacteriana de Acinetobacter baumannii. Conclusiones: Los resultados demostraron una asociación positiva entre la cantidad de biopelícula formada y la resistencia antibiótica, bacterias formadoras fuertes de biopelículas presentan mayor resistencia a los carbapenems. En cuanto a los genes, el gen ompA demostró una asociación con la cantidad de biofilm producido, bap y csuE son genes involucrados en el primer paso de formación de biofilm, pero no se asocian con la cantidad formada por la bacteria.

Abstract Introduction: Acinetobacter baumannii is the Gram-negative bacterium associated with hospital infections due to its great ease of survival in adverse conditions and the development of multi-resistance to various antimicrobials. For years, hospital outbreaks have been registered in different countries associated with this bacterium, which increased the interest in studying biofilms and the genes involved in their production, since an association with antibiotic resistance was demonstrated. Objectives: To establish a relationship between multiresistance to different antibiotics and biofilm formation in Acinetobacter baumannii isolates. Methods: acinetobacter baumannii strains were studied using real-time polymerase chain reaction (PCR) for the detection of bap, csuE, ompA, oxa-51 genes from 191 samples, in addition to the quantification of the biofilm formed following the technique described by Badmasti and Azizi. Results: this study was carried out on 191 Acinetobacter baumannii strains from two hospital centers for the identification of genes associated with biofilms and subsequent quantification according to the technique described by Badmasti and Azizi. Demonstrating an association between biofilms and Acinetobacter baumannii bacterial resistance. Conclusions: the results demonstrated a positive association between the amount of biofilm formed and antibiotic resistance. Strong biofilm-forming bacteria show greater resistance to carbapenems. Regarding the genes, the ompA gene showed an association with the amount of biofilm produced, bap and csuE are genes involved in the first step of biofilm formation, but they are not associated with the amount formed by the bacteria

AP-7 into the nucleus accumbens disrupts acquisition but does not affect consolidation in a passive avoidance task.

The effect of the blockade of N-methyl-D-aspartic acid (NMDA)-type glutamatergic receptors in the nucleus accumbens septi (Acc) during different phases of a passive avoidance task (step-through paradigm, two chambers) of learning was studied in male rats which had been bilaterally cannulated into the Acc. Animals were trained with a punishment procedure (3 s shock of 1 mA) to avoid one of the chambers. The rats received either saline or (+/-)2-amino-7-phosphonoheptanoic acid (AP-7) solution (1 microg/1 microl) 10 min before training (pretraining schedule) or immediately after the shock (posttraining schedule). In the test phase, the animals were placed back into the white chamber after 1 and 8 days later. In this moment, rats stayed there for 1 min, after which the time elapsed between the removal of the door to the introduction into the dark chamber of the head (Latency 1) and body (Latency 2) and fecal boli expelled were recorded. In the pretraining injection schedule, the drug treatment significantly reduced Latency 2 (P<.05) and fecal boli (P<0.01) on Day 1, and all parameters on Day 8 (P<.05). The posttraining injection schedule did not modify behavior. We conclude that a preshock NMDA-glutamatergic blockade of the Acc leads to cognitive disturbances during acquisition and a decrease in anxiety levels, but that the consolidation of a learned task is not affected by postshock administration.

Effects of selective NMDA and non-NMDA blockade in the nucleus accumbens on the plus-maze test.

Effect of blocking N-methyl-D-aspartic acid (NMDA) and non-NMDA-glutamatergic receptors on performance in the plus-maze was studied in male rats bilaterally cannulated into the nucleus accumbens (Acc). Rats were divided into seven groups that received either 1 microl injections of saline, (+/-)2-amino-7-phosphonoheptanoic acid (AP-7, 0.2, 0.5, or 1 microg) or 2,3 dioxo-6-nitro-1,2,3,4,tetrahydrobenzo-(f)quinoxaline-7-sulphonamide disodium (NBQX, 0.2, 0.5, or 1 microg) 15 min before testing. Time spent in open arm, time per entry, end arrivals, open, closed, and total arm entries, relationship between open-, closed-, and total arm entries, rearing, face-, head-, and body grooming, and number of fecal boli were recorded. Time spent in the open arm increased under AP-7 (0.5 and 1 microg; P<.01) and NBQX (1 microg; P<.05) treatment, whereas time per entry was increased only with AP-7 (1 microg; P<.05). Open arm entries were increased by the intermediate doses of AP-7 (0.5 microg; P<.01) and NBQX (0.5 microg; P<.05); end arrivals were increased by the intermediate dose of AP-7 (0.5 microg/1 microl, P<.05). The frequency of rearing, grooming, and closed arm entries was not affected by the treatment. We conclude that NMDA and non-NMDA-glutamatergic blockade in the Acc lead to a behavioral disinhibition of cortical influences with the median doses, but that at higher doses the blockers have an anxiolytic-like effect.