[Extended spectrum beta lactamases (ESBL) production in Acinetobacter baumannii strains isolated from Chilean hospitals belonging to VIII Region]. / Producción de beta-lactamasas de espectro extendido (BLEE) en cepas de Acinetobacter baumannii aisladas en hospitales de la VIIIa Región, Chile.

The resistance of Acinetobacter baumannii to ss-lactam antibiotics is mainly due to the synthesis of ss-lactamases. From a clinical point of view, this bacteria and others, grouped under the acronym SPACE (S: Serratia, P: Pseudomonas, A: Acinetobacter, C: Citrobacter, E: Enterobacter) are essentially Amp-C ss-lactamases producers. There is no local information about ESBL presence in Acinetobacter. We studied ESBL production using the Ho and col. technique modified by adding cloxacillin as chromosomal ss-lactamases inhibitor. From 69 isolates, with resistance to at least one third generation cephalosporin, only 7 showed positive synergy test. Four of these amplified for TEM family gene, and one of these amplified also for the OXA family. Our study found a low ESBL production percentage, which agrees with the premise of Amp-C as the main mechanism of resistance to ss-lactam antibiotics in A. baumannii. However, the ESBL description in these bacteria emphasizes the capacity of expressing multiple resistance mechanisms.

Producción de ß-lactamasas de espectro extendido (BLEE) en cepas de Acinetobacter baumannii aisladas en hospitales de la VIIIª Región, Chile / Extended spectrum ß-lactamases (ESBL) production in Acinetobacter baumannii strains isolated from Chilean hospitals belonging to VIII Region

The resistance of Acinetobacter baumannii to ß-lactam antibiotics is mainly due to the synthesis of ß-lactamases. From a clinical point of view, this bacteria and others, grouped under the acronym SPACE (S: Serratia, P: Pseudomonas, A: Acinetobacter, C: Citrobacter, E: Enterobacter) are essentially Amp-C ß-lactamases producers. There is no local information about ESBL presence in Acinetobacter. We studied ESBL production using the Ho and col. technique modified by adding cloxacillin as chromosomal ß-lactamases inhibitor. From 69 isolates, with resistance to at least one third generation cephalosporin, only 7 showed positive synergy test. Four of these amplified for TEM family gene, and one of these amplified also for the OXA family. Our study found a low ESBL production percentage, which agrees with the premise of Amp-C as the main mechanism of resistance to ß-lactam antibiotics in A. baumannii. However, the ESBL description in these bacteria emphasizes the capacity of expressing multiple resistance mechanisms.

La resistencia de Acinetobacter baumannii a antimicrobianos ß-lactámicos se debe fundamentalmente a la síntesis de ß-lactamasas. Del punto de vista clínico se considera que esta bacteria, y otras agrupadas en el acrónimo SPACE (Serratia, Pseudomonas, Acinetobacter, Citrobacter, Enterobacter), son predominantemente productoras de ß-lactamasas tipo AmpC. No hay información en nuestro país sobre presencia de ß-lactamasas de espectro extendido (BLEE) en Acinetobacter. Se estudió la producción de BLEE en cepas de Acinetobacter, mediante una modificación de la técnica de Ho y col adicionando cloxacilina como inhibidor de ß-lactamasas cromosomales. De 69 cepas con resistencia al menos a una cefalosporina de tercera generación, sólo siete presentaron sinergia positiva. Cuatro cepas amplificaron por RPC un fragmento intragénico de genes de familia TEM y una de ellas amplificó, además, para el gen de la familia OXA. Se evidenció un bajo porcentaje de producción de BLEE, lo que confirma que la producción de Amp-C es el principal mecanismo de resistencia de A. baumannii a ß-lactámicos. Sin embargo, la descripción de BLEE en esta bacteria, enfatiza su capacidad de albergar múltiples mecanismos de resistencia.

Use of 137Cs measurements to estimate changes in soil erosion rates associated with changes in soil management practices on cultivated land.

Intensification of agricultural production in south-central Chile since the 1970s has caused problems of increased soil erosion and associated soil degradation. These problems have prompted a shift from conventional tillage to no-till management practices. Faced with the need to establish the impact of this shift in soil management on rates of soil loss, the use of caesium-137 (137Cs) measurements has been explored. A novel procedure for using measurements of the 137Cs depth distribution to estimate rates of soil loss at a sampling point under the original conventional tillage and after the shift to no-till management has been developed. This procedure has been successfully applied to a study site at Buenos Aires farm near Carahue in the 9th region of Chile. The results obtained indicate that the shift from conventional tillage to no-till management has caused net rates of soil loss to decrease to about 40% of those existing under conventional tillage. This assessment of the impact of introducing no-till management at the study site must, however, be seen as provisional, since only a limited number of sampling points were used. A simplified procedure aimed at documenting the reduction in erosion rates at additional sampling points, based solely on measurements of the 137Cs inventory of bulk cores and the 137Cs activity in the upper part of the soil has been developed and successfully tested at the study site. Previous application of 137Cs measurements to estimate erosion rates has been limited to estimation of medium-term erosion rates during the period extending from the beginning of fallout receipt to the time of sampling. The procedures described in this paper, which permits estimation of the change in erosion rates associated with a shift in land management practices, must be seen as representing a novel application of 137Cs measurements in soil erosion investigations.

Presencia de integrones y su relación con la resistencia a cefalosporinas de tercera generación en cepas de acinetobacter baumannii de origen nosocomial / Presence of integrons and their relationship with the resistance to third generation cephalosporins among nosocomial isolates of acinetobacter baumannii

Background: Acinetobacter baumannii is an important etiological agent causing nosocomial infections. High level of resistance for different kind of antimicrobials has been observed, including ß-lactam antibiotics. This feature, chromosomal or plasmid encoded, has been associated to integrons harbouring antibiotic resistance gene cassettes. Aims: To investigate the presence of integrons among clinical isolates resistant to third generation cephalosporins (3GC). Material and methods: One hundred A. baumannii strains isolated from several Chilean hospitals were included in this study. Minimal inhibitory concentrations (MIC) of 3GC by an agar dilution method were carried out. Integrons class 1, 2 and 3 were investigated by colony blot hybridisation and confirmed by PCR. Results: High level of resistance to all assayed 3GC was observed. On the other hand, integrón class 2 was the most prevalent (77 percent of isolates) followed by integron class 1 (52 percent). Forty six percent of isolates hybridised with probes for both of them. However, no positive hybridisation was detected for integron class 3. Conclusions: Nevertheless, most isolates harboured one or both class of integron; there was no direct relationship between the presence of these genetic structures and the resistance to this kind of ß-lactam antibiotics

Psychiatric crisis: its approach in a crisis intervention unit - Poster presentation

A retrospective and descriptive study of patients at the Crisis Intervention Unit of the Provincial Psychiatric Hospital of Holguin, Cuba, was undertaken in the first semester of 1998. In three hundred and nine patients we studied, the sociodemographic variables of age and sex as well as crisis type and triggering conflict areas, the diagnostic procedure used, biological therapeutic resources, and nosologic diagnostic at discharge. A slight predominance of males was found, and the greater number of patients was between age 25 and 44 years. The depressive and anxiety crisis were the most frequently found. Several diagnostic resources were employed. The multivalence treatment proved that the most used psychodrugs were tricyclic antidepresives and anxiolytics. The electroconvulsive therapy was employed only in 4 cases. The short psychotherapy modalities were applied in a high percentage of the studied cases prevailing the support, rational psychotherapies and handling attitude. The most frequent diagnostics were: Personality Disorders, Schizophrenia, Neurosis and Situational Disorders. The effectiveness of the Crisis Intervention Unit is presented as model for dealing with patients undergoing psychiatric crisis (AU)