Retos en el diagnostico de las intoxicaciones por setas

La recolección y consumo de setas es una afición cada vez más popular en nuestro país. Los micetismos constituyen una variedad de síndromes clínicos bien descritos si bien se siguen identificando especies tóxicas o nuevas patologías. Esto queda ejemplificado en la asociación reciente de un cuadro de rabdomiolisis después de haber ingerido Tricholoma equestre, o seta de los caballeros, considerada desde antiguo como un comestible de gran calidad. Por otro lado en el área de la Toxinología se precisa aplicar una medicina basada en la evidencia siendo básico el conocimiento de la epidemiología de los micetismos en cada centro médico. El análisis de laboratorio sirve para confirmar el diagnóstico de un micetismo, evitar tratamientos y hospitalizaciones innecesarias, diagnosticar síndromes mixtos o micetismos cuyo periodo de incubación quede solapado y aportar nuevos taxones al catálogo de especies tóxicas. Las muestras disponibles van a condicionar el análisis a realizar. Con el estudio de restos botánicos se llega a establecer al menos el género en más del 80 por ciento de los casos. La búsqueda de las toxinas en muestras botánicas, y especialmente de amanitinas en orina, permite el diagnóstico confirmativo. La dificultad que presenta el estudio morfológico y la determinación de toxinas en muestras en mal estado de conservación, hace que la aplicación de marcadores genéticos pudiera ser una buena herramienta complementaria. La creación de una base de datos de las regiones con interés en la identificación genética de setas tóxicas de la península ibérica, está siendo objeto de investigación en nuestro laboratorio (AU)

Generation of a reproducible nutrient-depleted biofilm of Escherichia coli and Burkholderia cepacia.

An in vitro method of growing bacteria as a defined nutrient-depleted biofilm is proposed. The medium was defined nutritionally in terms of the quantitative composition and by the total amount of nutrient required to achieve a defined population size. Escherichia coli and Burkholderia cepacia were incubated on a filter support placed on a defined volume of solid medium. The change of biomass of the biofilm population was compared with the change in a planktonic culture. The size of the population in stationary phase was proportional to the concentration of limiting substrate up to 40 mumol cm-1 glucose for E. coli and up to 2.7 x 10(-9) mol cm-2 iron for B. cepacia. Escherichia coli growing exponentially had a growth rate of mu = 0.30 h-1 in a biofilm and mu = 0.96 h-1 in planktonic culture. The growth rate, mu, for exponentially growing B. cepacia in a biofilm was 1.12 h-1 and in planktonic culture 0.78 h-1. This method allows the limitation of the size of a biofilm population to a chosen value.

Carbapenem resistance in Pseudomonas aeruginosa from cystic fibrosis patients.

The evolution of imipenem resistance was evaluated in Pseudomonas aeruginosa sequentially isolated from 42 patients with cystic fibrosis. Susceptibility was determined using a commercial microdilution system and imipenem resistance was confirmed by the agar dilution technique. Resistance to imipenem increased during the years from 1988 to 1992. A total of 12 patients (28.5%) carried resistant strains (11.6% of the total P. aeruginosa isolates) but only two of them were treated with the carbapenem. The other patient under imipenem treatment did not harbour resistant isolates. Sixty-four per cent of the imipenem resistant isolates were also meropenem resistant and showed low susceptibility to the other beta-lactams and tobramycin and amikacin. Twenty-one strains were selected for biochemical study. Imipenem susceptible strains showed normal OprD in two strains and diminished OprD in two more. Five strains with MIC of imipenem of 4-8 mg/L lacked OprD while another two had a band with decreased density. All strains with MIC higher than 8 completely lacked this band in western-blot analysis. Imipenem MICs of 0.5-2 mg/L only slightly increased to 1-4 mg/L when a pattern of beta-lactamase derepression was observed. While those with imipenem MICs between 8-16 mg/L increased the imipenem MIC to 16-64 mg/L in the population with a beta-lactamase derepression phenotype.

[Microbiological parameters of clinical interest in pulmonary infection in cystic fibrosis]. / Parámetros microbiológicos de interés clínico en la infección pulmonar en la fibrosis quística.

BACKGROUND: A 5-year study in patients with cystic fibrosis was carried out in order to gain a better understanding of the microbiological factors influencing clinical status and evolution. METHODS: Fifty-two patients were evaluated (mean age 16.6 years, range 0-36) during a 5 years-period (July 1988- July 1992). The clinical score of Shwachman and pulmonary function were evaluated at the beginning and at the end of the study period. Quantitative bacterial cultures were performed every 3 weeks recording the different colonical morphotypes of Pseudomonas aeruginosa. RESULTS: Beside the expected results regarding the prevalence of P. aeruginosa (80.7%) and Staphylococcus aureus (65.5%), a low rate of chronic infection with Burkholderia cepacia (1.9%) and high with S. maltophilia (9.6%) was found and it is worth noting the presence of Salmonella spp. in 3 patients. Microbial colonization followed the classical age-related sequence with 53.8% of patients older than 10 colonized with mucoid strains of P. aeruginosa. Colonization with mucoid Pseudomonas, increase in sputum bacterial counts and high diversity in colonizing morphotypes were parameters related with reduced clinical scores. CONCLUSIONS: The sequential study of the bacterial colonization in cystic fibrosis is important to follow the prognosis and evolution of the disease, and therefore, to choose the most effective therapy.

[Detection of serum IgG (ELISA) against Helicobacter pylori: relationship with age and gastroduodenal disease]. / Detección de IgG sérica (ELISA) frente a Helicobacter pylori: relación con la edad y patología gastroduodenal.

OBJECTIVE: An attempt was made to investigate the serological response against Helicobacter pylori by using a IgG serum detection technique (ELISA Biometra) to establish a relationship with age and gastroduodenal pathology. The serological response was compared with the microbiologic and histologic studies of biopsy samples from 4 locations in each patient: duodenal bulb, gastric antrum, corpus and fundus. PATIENTS: A total of 309 patients with gastrointestinal symptoms who underwent an upper digestive endoscopy were included. RESULTS: The overall sensitivity of the serological technique (cut-off value 15 U/ml) was 89.3%, the specificity 75.7%, the positive predictive value 96.9% and the negative predictive value 45.4%. The mean titer in patients with a negative microbiology increased with age: 13.5 U/ml, 14-30 years; 10.0 U/ml, 31-50 years; 18.5 U/nl, 51-65 years and 29.2 U/ml, > 65 years. By increasing the cut-off value to 20 and 30 U/ml in the last two age groups, the specificity increased without a significant decrease in the sensitivity. Patients without abnormal findings at endoscopy had mean titers considerably lower (64.7 U/ml) than those with the stomach resected -Billroth I or II- (99.6 U/ml) and those with gastritis, duodenitis and ulcus (86.7-83.1 U/ml), Patients with gastritis but without acute inflammatory activity had mean titers (62.5 U/ml) lower than those observed in patients with active gastritis (p < 0.01) and increased in parallel with the increasing activity of gastritis. In contrast, patients with atrophic gastritis had the lowest mean titers (54 U/ml). CONCLUSIONS: Our results suggest that the cut-off value in the serological technique should be increased according to the patient's age. Moreover, there is a clear relationship between the serum levels of IgG and the activity of gastritis.

[Evaluation of a selective medium for the isolation of Moraxella catarrhalis]. / Evaluación de un medio selectivo para aislamiento de Moraxella catarrhalis.

The recovery rate of Moraxella catarrhalis in a selective culture medium with acetazolamide and in a conventional blood-agar medium was compared from 1291 samples from the respiratory tract and conjunctivae of children and adults with respiratory and ocular symptomatology. M. catarrhalis was recovered in 215 samples on the acetazolamide medium, and only. 18 cases in the blood agar medium (p < 0.001). The highest recovery of M. catarrhalis was in samples with an accompanying flora, either pathogenic or commensal, such as pharyngeal and nasal exudates. The prevalence of M. catarrhalis in adults and children was 2% and 28%, respectively. We therefore, recommend the use of the acetazolamide medium for the recovery of M. catarrhalis in samples where M. catarrhalis is expected to be present with an accompanying flora.

Clindamycin and tetracycline as immunomodulating agents: an in vivo study.

The present study was undertaken to determine the effects of clindamycin and tetracycline, both intravenously administered, on antibody response to thymus-dependent antigen (PC-KLH) in BALB/c mice. The immunological parameters evaluated were: DPFC/spleen (direct plaque forming-cells), antibody secretion median rate (PC50), heterogeneity index (Hi), number of total splenic lymphocytes and cellular viability. The results showed that clindamycin (i.v.) increased the humoral response; 28 mg/kg was the dose that showed the greatest enhancement (+73%). The PC50 was not affected by clindamycin but Hi decreased at 28 mg/kg and increased at 2.8 mg/kg doses, although neither result was statistically significant. When tetracycline was given i.v., a slight decrease in the anti-PC DPFC number was observed. Although the PC50 was greater at 10 mg/kg (p less than 0.05), Hi was smaller at the 1 mg/kg dose (p less than 0.05).