Prospective multicentre study of rectal carriage of multidrug-resistant Enterobacteriaceae among health-care workers in Spain.

OBJECTIVES: To investigate the rectal carriage of multidrug-resistant Enterobacteriaceae (colistin-resistant, extended-spectrum ß-lactamase (ESBL) -producers and/or carbapenemase-producers) among health-care workers (HCWs) from six Spanish hospitals. METHODS: Rectal swabs from 258 HCWs, employed in intensive care units, haematology wards and clinical microbiology laboratories from six hospitals in northern Spain were studied. They were cultured in selective media for Gram-negative resistant bacteria. Detection of antimicrobial resistance genes and multilocus sequence typing were performed by PCR and further sequencing. A questionnaire including data related to risk factors of colonization/infection by resistant bacteria (age, gender, chronic diseases, immunosuppressive therapies, invasive procedures or antimicrobial treatments) was given to each participant. RESULTS: No carbapenemase-producing Enterobacteriaceae were recovered. However, 8/258 HCWs (3.1%) were positive for ESBL-producing isolates. This rate was not higher than the colonization rate previously reported in Spain for healthy people in the community. Five isolates showed high-level resistance to colistin (MICs ranging from 8 to 128 mg/L) but all of them were negative for the mcr genes tested. No statistically significant risk factors for gut colonization by ESBL-producing or colistin-resistant Enterobacteriaceae were identified among the HCWs participating in the study. CONCLUSIONS: Our data suggest that working in hospitals does not represent a risk for rectal carriage of multidrug-resistant Enterobacteriaceae.

Discovery of gymnodimine fatty acid ester metabolites in shellfish using liquid chromatography/mass spectrometry.

RATIONALE: Gymnodimines (GYMs) are fast-acting toxins that belong to the cyclic imine group, a subclass of lipophilic marine toxins. GYMs are considered to be emerging toxins but have not yet been linked to incidents of human poisoning, Limited knowledge on the metabolism of GYMs means that a proper risk assessment has not been possible and caution must be taken when establishing the relevance of GYMs in terms of food safety of marine products. METHODS: A series of mass spectrometric experiments involving precursor and product ion scans, selected reaction monitoring (SRM), and high-resolution mass spectrometry (MS) were used to detect and confirm 10-O-acyl esters of gymnodimine-A (1). RESULTS: We have detected for the first time the presence of a range of acyl ester derivatives of GYMs in shellfish samples from the Gulf of Gabes, Tunisia. The MS fragmentation pathways of 1 and its esters were also elucidated. Partial synthesis of a palmitic acid ester of 1 facilitated confirmation of identity and calibration of SRM analyses. Evidence of acyl ester metabolites of gymnodimine-B and -C was also obtained. CONCLUSIONS: A semi-quantitative analysis indicated that the majority of GYMs present in the sample were in the acylated form (>90%), suggesting that these compounds must not be neglected when trying to understand the risks associated with GYMs. There is a clear need for toxicology studies on these esters and assessment of bio-availability to humans.

Infección por el virus H1N1: hallazgos en la radiografía simple de tórax / H1N1 virus infection: chest radiographic findings

Objetivo. Mostrar los hallazgos en la radiografía de tórax (RT) de pacientes con infección confirmada por la nueva variante del virus de la gripe A (H1N1) correlacionándolos con la historia y evolución clínica. Material y métodos. Revisión de la historia clínica y estudios radiológicos de 99 pacientes con infección por la nueva variante del virus de gripe A ingresados en dos hospitales del Servicio Cántabro de Salud. Los hallazgos en la RT fueron clasificados por el patrón parenquimatoso y la distribución de las lesiones. Resultados. De los 99 pacientes evaluados, 28 presentaron alteraciones en la RT realizada al ingresar. En estos 28 pacientes los hallazgos fueron: condensación en 19, condensación más vidrio deslustrado en 7 y vidrio deslustrado en dos; en 17 la distribución de las lesiones fue difusa, en 17 bilateral, y por campos los más afectados fueron el inferior y el medio. Trece pacientes experimentaron una progresión de las lesiones y los 7 que precisaron ventilación mecánica mostraron con mayor frecuencia en la RT del ingreso una distribución difusa de las lesiones y un mayor número de campos pulmonares afectos. Los pacientes con RT patológica fueron preferentemente varones, fumadores y presentaron disnea, dolor pleurítico y diarrea (p<0,05). Conclusión. La mayoría de los pacientes con infección por la nueva variante del virus de la gripe A no presentaron alteraciones en la RT del ingreso; sin embargo, cuando estaban presentes, el patrón predominante fue una condensación de distribución difusa, bilateral y con predominio en las bases. El derrame pleural y las adenopatías hiliares o mediastínicas fueron infrecuentes (AU)

Objective. To show the plain chest film findings in patients with confirmed infection with the new variant of the influenza A (H1N1) virus and to correlate these findings with the clinical history and evolution. Material and methods. We reviewed the clinical histories and radiological studies in 99 patients infected with the new variant of H1N1 influenza who were admitted in two Hospitals in Cantabria, Spain. Plain chest film findings were classified according to their parenchymal pattern and the distribution of the lesions. Results. Of the 99 patients evaluated, 28 had changes on the plain chest film acquired at admission. In these 28 patients, the findings were: condensation in 19, condensation and ground-glass opacities in 7, and ground-glass opacities in 2; the distribution of the lesions was diffuse in 17 patients and bilateral in 17, with the lower and middle lobes being the most frequently affected. The lesions progressed in 13 patients, and the 7 patients who required mechanical ventilation had a higher frequency of diffuse lesion distribution and more lung fields affected on the plain chest field acquired at admission. Pathological findings on plain chest films were more common in males, in smokers, and in patients who presented with shortness of breath, pleuritic pain, and diarrhea (P<0.05). Conclusion. Most patients infected with the new variant of the H1N1 virus had no alterations on the plain chest film acquired on admission; when findings were present, the predominant pattern was diffuse, bilateral condensation mainly involving the bases of the lungs. Pleural effusion and hilar or mediastinal lymph node enlargement were uncommon (AU)

The implementation of liquid chromatography tandem mass spectrometry for the official control of lipophilic toxins in seafood: single-laboratory validation under four chromatographic conditions.

We performed a comprehensive study to assess the fit for purpose of four chromatographic conditions for the determination of six groups of marine lipophilic toxins (okadaic acid and dinophysistoxins, pectenotoxins, azaspiracids, yessotoxins, gymnodimine and spirolides) by LC-MS/MS to select the most suitable conditions as stated by the European Union Reference Laboratory for Marine Biotoxins (EURLMB). For every case, the elution gradient has been optimized to achieve a total run-time cycle of 12 min. We performed a single-laboratory validation for the analysis of three relevant matrices for the seafood aquaculture industry (mussels, pacific oysters and clams), and for sea urchins for which no data about lipophilic toxins have been reported before. Moreover, we have compared the method performance under alkaline conditions using two quantification strategies: the external standard calibration (EXS) and the matrix-matched standard calibration (MMS). Alkaline conditions were the only scenario that allowed detection windows with polarity switching in a 3200 QTrap mass spectrometer, thus the analysis of all toxins can be accomplished in a single run, increasing sample throughput. The limits of quantification under alkaline conditions met the validation requirements established by the EURLMB for all toxins and matrices, while the remaining conditions failed in some cases. The accuracy of the method and the matrix effects where generally dependent on the mobile phases and the seafood species. The MMS had a moderate positive impact on method accuracy for crude extracts, but it showed poor trueness for seafood species other than mussels when analyzing hydrolyzed extracts. Alkaline conditions with EXS and recovery correction for OA were selected as the most proper conditions in the context of our laboratory. This comparative study can help other laboratories to choose the best conditions for the implementation of LC-MS/MS according to their own necessities.

H1N1 virus infection: chest radiographic findings.

OBJECTIVE: To show the plain chest film findings in patients with confirmed infection with the new variant of the influenza A (H1N1) virus and to correlate these findings with the clinical history and evolution. MATERIAL AND METHODS: We reviewed the clinical histories and radiological studies in 99 patients infected with the new variant of H1N1 influenza who were admitted in two Hospitals in Cantabria, Spain. Plain chest film findings were classified according to their parenchymal pattern and the distribution of the lesions. RESULTS: Of the 99 patients evaluated, 28 had changes on the plain chest film acquired at admission. In these 28 patients, the findings were: condensation in 19, condensation and ground-glass opacities in 7, and ground-glass opacities in 2; the distribution of the lesions was diffuse in 17 patients and bilateral in 17, with the lower and middle lobes being the most frequently affected. The lesions progressed in 13 patients, and the 7 patients who required mechanical ventilation had a higher frequency of diffuse lesion distribution and more lung fields affected on the plain chest field acquired at admission. Pathological findings on plain chest films were more common in males, in smokers, and in patients who presented with shortness of breath, pleuritic pain, and diarrhea (P<0.05). CONCLUSION: Most patients infected with the new variant of the H1N1 virus had no alterations on the plain chest film acquired on admission; when findings were present, the predominant pattern was diffuse, bilateral condensation mainly involving the bases of the lungs. Pleural effusion and hilar or mediastinal lymph node enlargement were uncommon.

High dietary arachidonic acid levels affect the process of eye migration and head shape in pseudoalbino Senegalese sole Solea senegalensis early juveniles.

The effect of high dietary levels of arachidonic acid (ARA) on the eye migration and cranial bone remodelling processes in Senegalese sole Solea senegalensis early juveniles (age: 50 days post hatch) was evaluated by means of geometric morphometric analysis and alizarin red staining of cranial skeletal elements. The incidence of normally pigmented fish fed the control diet was 99·1 ± 0·3% (mean ± s.e.), whereas it was only 18·7 ± 7·5% for those fed high levels of ARA (ARA-H). The frequency of cranial deformities was significantly higher in fish fed ARA-H (95·1 ± 1·5%) than in those fed the control diet (1·9 ± 1·9%). Cranial deformities were significantly and negatively correlated with the incidence of normally pigmented animals (r² = -0·88, P < 0·001, n = 16). Thus, fish displaying pigmentary disorders differed in the position of their eyes with regard to the vertebral column and mouth axes, and by the interocular distance and head height, which were shorter than in fish not displaying pigmentary disorders. In addition to changes in the positioning of both eyes, pseudoalbino fish showed some ARA-induced osteological differences for some of the skeletal elements from the splanchnocranium (e.g. right premaxillary, dentary, angular, lacrimal, ceratohyal and branchiostegal rays) and neurocranium (e.g. sphenotic, left lateral ethmoid and left frontal) by comparison to normally pigmented specimens. Pseudoalbino fish also had teeth in both lower and upper jaws. This is the first study in Pleuronectiformes that describes impaired metamorphic relocation of the ocular side eye, the right eye in the case of S. senegalensis, whereas the left eye migrated into the ocular side almost normally.

Towards the standardisation of the neuroblastoma (neuro-2a) cell-based assay for ciguatoxin-like toxicity detection in fish: application to fish caught in the Canary Islands.

The ouabain/veratridine-dependent neuroblastoma (neuro-2a) cell-based assay (CBA) was applied for the determination of the presence of ciguatoxin (CTX)-like compounds in ciguatera-suspected fish samples caught in the Canary Islands. In order to avoid matrix interferences the maximal concentration of wet weight fish tissue exposed to the neuro-2a cells was set at 20 mg tissue equivalent (TE) ml(-1) according to the sample preparation procedure applied. In the present study, the limit of quantification (LOQ) of CTX1B equivalents in fish extract was set at the limit of detection (LOD), being defined as the concentration of CTX1B equivalents inhibiting 20% cell viability (IC(20)). The LOQ was estimated as 0.0096 ng CTX1B eq.g TE(-1) with 23-31% variability between experiments. These values were deemed sufficient even though quantification given at the IC(50) (the concentration of CTX1B equivalents inhibiting 50% cell viability) is more accurate with a variability of 17-19% between experiments. Among the 13 fish samples tested, four fish samples were toxic to the neuro-2a cells with estimations of the content in CTX1B g(-1) of TE ranging from 0.058 (± 0.012) to 6.23 (± 0.713) ng CTX1B eq.g TE(-1). The high sensitivity and specificity of the assay for CTX1B confirmed its suitability as a screening tool of CTX-like compounds in fish extracts at levels that may cause ciguatera fish poisoning. Species identification of fish samples by DNA sequence analysis was conducted in order to confirm tentatively the identity of ciguatera risk species and it revealed some evidence of inadvertent misidentification. Results presented in this study are a contribution to the standardisation of the neuro-2a CBA and to the risk analysis for ciguatera in the Canary Islands.

Evidence of okadaic acid production in a cultured strain of the marine dinoflagellate Prorocentrum rhathymum from Malaysia.

Protein phosphatase inhibition assay (PPIA), Neuroblastoma cell-based assay (Neuro-2a CBA) and LC-MS/MS analysis revealed for the first time the production of okadaic acid (OA) by a Prorocentrum rhathymum strain. Low amounts of OA were detected by LC-MS/MS analysis. Inhibition of PP2A activity and a weak toxicity to the Neuro-2a CBA were also observed.

Cell-based assay coupled with chromatographic fractioning: a strategy for marine toxins detection in natural samples.

Cell-based assays (CBA) have been proposed for the evaluation of toxicity caused by marine toxins in natural samples (fish, shellfish and microalgae). However, their application has been hindered due to the interferences present in biological matrices that may cause cellular response and interfere in toxicity evaluation. This work reviews in an extensive introduction the use of CBA for toxicity evaluation of marine toxins. Afterwards, the coupling of chromatographic fractioning with neuroblastoma Neuro-2a CBA is presented to enhance the applicability of CBA for complex matrices. Examples of application are provided for mussel samples (Mytilus galloprovincialis) and microalgae (Gambierdiscus sp.), and the results demonstrated the great potential of the combined strategy for reliable toxicological evaluation without ethical concern. Fractioning of an equivalent of 72 mg eq mL(-1) of mussel sample allowed the identification of non-toxic and toxic fractions whereas only 2.5mg eq mL(-1) of non-purified mussel sample was responsible for 20% of cell mortality. Furthermore, the application of CBA allowed selectively distinguishing between ciguatoxin-like and other unspecific toxicity in Gambierdiscus sp. extract.

Determination of yessotoxins and pectenotoxins in shellfish by capillary electrophoresis-electrospray ionization-mass spectrometry.

Conditions for the determination of lipophilic marine toxins, such as yessotoxins and pectenotoxins (PTX)-6, were investigated with capillary electrophoresis coupled to mass spectrometry (MS) with an electrospray ionization source. After optimization, a simple and MS compatible alkaline volatile buffer solution of ammonium acetate was selected as background electrolyte, with isopropanol/water (80/20, v/v) sheath liquid modified with ammonium acetate used at the electrospray ionization (ESI) source. Previously to capillary electrophoresis (CE) separations, the application of an on-line sample pre-concentration approach based on field-amplified sample stacking was accomplished to increase sensitivity. As a result, the limits of detection provided by capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) were 0.02 microg ml(-1) (0.01 microg g(-1)), which corresponded to 1.25 pg for yessotoxin and 0.25 microg ml(-1) (0.13 microg g(-1) and 13.25 pg on capillary) for PTX-6. Accuracy tests showed 97.7% recovery from spiked blank mussel samples that showed no significant matrix influence running under optimal conditions. Intermediate precision was close to 4% relative standard deviation (RSD) for the migration time, and an RSD of 7.5% for peak areas. The method was successfully applied to naturally contaminated seafood samples in which yessotoxins and pectenotoxins-6 were clearly determined. This work demonstrated the potential of CE-ESI-MS to be applied for a sensitive determination of lipophilic toxins from the marine environment as alternative to liquid chromatography-electrospray ionization-single quadrupole mass spectrometry (LC-ESI-MS) for this purpose.

Campylobacter fetus subspecies fetus bacteremia associated with chorioamnionitis and intact fetal membranes.

Campylobacter fetus subspecies fetus was isolated from the blood of a patient with chorioamnionitis and intact fetal membranes. The mother improved after appropriate antibiotic treatment, but the infant died of neonatal infection a few minutes after delivery. This is a very unusual etiology of intra-amniotic infection.

Dermatomicosis de los pies asociados a los trabajos del mar / Fungal foot infections associated with marine occupations

Objetivos: estimar la prevalencia de dermatomicosis de los pies en el colectivo de los trabajadores del mar del Principado de Asturias y comparar con los resultados existentes en población general. Métodos: se realizó un estudio epidemiológico descriptivo transversal del colectivo de los trabajadores del mar que acudieron a reconocimiento médico obligatorio entre Octubre de 1996 y Abril de 1998. Se les realizó un examen clínico detallado, se tomaron muestras de piel que se cultivaron en medios específicos para hongos y se obtuvo información de posibles variables de interés en relación con su actividad laboral como antigüedad laboral, tipo y puesto de trabajo. Se calcularon las razones de prevalencia y su significación estadística. Resultados: la tasa de respuesta media fue del 18%, siendo el número total de participantes de 255. El 48% de los examinados presentaban lesiones clínicas compatibles con dermatomicosis y en el 11,4% de los casos se obtuvo un resultado positivo en los cultivos siendo el T. Mentagrophytes el hongo más frecuentemente encontrado. Discusión: aunque no podemos extrapolar nuestros resultados debido a la baja tasa de respuesta, la presencia de lesiones clínicas compatibles con la patología en casi la mitad de los trabajadores estudiados, parece suficiente motivo para seguir investigando en esta línea. Los trabajadores de la pesca y los que ocupan el puesto de trabajo de marinero presentan una mayor prevalencia de dermatomicosis que el resto de trabajadores del mar (AU)

Objectives: The aim of the study was to identify the prevalence of dermatomycosis in seaworkers of Asturias (Spain) in order to compare it with the data of prevalence of the general population. Methods: Descriptive epidemiological study. We obtained the seaworkers occupational data from occupational medical examination between October 1996 and April 1998. The questionnaire was about working conditions and we took samples of their foot. Results: The response rate was 18% including 255 seaworkers. 48% of them have had mycotical clinical injuries. T. Mentagrophytes was the fungus usually found. Conclussions: Due to the lower response we cannot deduce the real prevalence of this workers. Our data are so important to go on investigate mycotical patology in seaworkers in order to asses the occupational mycotical examination (AU)

Effectiveness and safety of balloon dilation of the papilla and the use of an occlusion balloon for clearance of bile duct calculi.

OBJECTIVE: The purpose of this study was to describe a technique for percutaneous bile duct stone clearance by pushing the stones into the small bowel after balloon dilation of the papilla. SUBJECTS AND METHODS: During a 2-year period, 38 patients were treated percutaneously for stones in the biliary tree. Twenty-one patients were treated through a T tube or transcystic tract. Seventeen patients were treated through a transhepatic tract. Twenty-three patients had one stone each. Eight patients had two stones, and seven patients had three or more calculi. Stone size ranged from 3 to 16 mm in diameter (mean size, 6.7 nm). Balloon diameter based on the transverse diameter of the stones ranged from 7 to 18 mm (mean, 6.7 mm). An 11.5-mm occlusion balloon was used for pushing the stones through a 7- to 9-French vascular introducer. A catheter was left in the common bile duct from 1 to 6 days for external drainage. RESULTS: The technique was successfully used for clearance of stones in 36 (94.7%) of the 38 patients. With 29 patients, the procedure was performed with only one attempt. Two attempts were necessary for five patients, and three attempts were necessary for four patients. Two major complications were cholangitis and biliary pleural effusion. No deaths were related to the procedure. CONCLUSION: Percutaneous bile duct stone clearance by dilation of the papilla and evacuation of the stones in an antegrade fashion with an occlusion balloon is a safe and effective technique. It can be an alternative to basketing stones in selected patients.

Rapid screening tests for determining in vitro susceptibility of herpes simplex virus clinical isolates.

The susceptibility of human herpes simplex virus (HSV) to acyclovir (ACV) was determined with the use of a single dose of the drug (1 and 2 micrograms of ACV per ml for HSV-1 and HSV-2, respectively) in two rapid assays: a rapid cytopathic effect inhibitory assay (Rapid CIA) and a rapid dye uptake assay (Rapid DUA). These tests allow the simultaneous determination of virus titer and susceptibility to ACV at a determined viral concentration (100 50% tissue culture infective doses and 100 50% dye uptake units). These tests were compared with a conventional susceptibility assay (dye uptake assay) and showed similar results. Indeterminate results with the Rapid CIA appeared in 3 of 30 samples. With the use of both Rapid CIA and Rapid DUA, we were able to determine the susceptibility of 100% of the isolates. The rapid tests, unlike conventional assays, are able to provide susceptibility results within 3 days after the virus has been isolated from a clinical specimen and could thus play a direct role in therapeutic decisions.

Characterization of the lung cancer epidemic in the European Union (1970-1990).

To characterize the situation of the lung cancer epidemic in the former European Community countries, we analyzed mortality time trends between 1970 and 1990, and by using Poisson log-linear models, we compared patterns of evolution between Mediterranean and non-Mediterranean countries. To ascertain the course traced by the cohort effect and the inflection points marking shifts in trend in the epidemic, we made use of invariant parameters from age-period-cohort models (net drift, curvature) and restricted slope range for cohort effect. Regarding men, whereas non-Mediterranean countries had already initiated the downward phase of the process, the Mediterranean countries, with the single exception of Italy, proved to be entirely in the development stage. Women evinced a different pattern of evolution in regard to both rate magnitudes and trend behavior. Apart from Spain and Greece, a sharp rise in adjusted and specific rates was observed for all countries.

Isolation of influenza virus in human lung embryonated fibroblast cells (MRC-5) from clinical samples.

Ninety-four pharyngeal swab samples corresponding to 94 patients with suspected influenza virus infection were inoculated in Madin-Darby canine kidney (MDCK) cells, the conventional cell system for the isolation of influenza virus, and in fibroblastic human embryo lung (MRC-5) cells, a cell system less commonly used for this purpose but one frequently used in clinical virology laboratories. Both cell preparations were treated with trypsin. Influenza virus was recovered from 15% of the samples inoculated in MDCK cells and from 18% of those inoculated in MRC-5 cells. The use of MRC-5 cells can simplify the search for respiratory viruses and would assist in the rapid detection of influenza virus during new epidemics.

Prospective study of antigenemia, plasma viremia and lymphocytic viremia in HIV-infected hemophiliacs.

A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51% of the patients and from PBMC in 87.5% of the patients. The incidence of HIV isolation in asymptomatic patients (42.8%) was similar to that found in symptomatic patients (51.4%). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p < 0.05). Plasma viremia was closely associated (p < 0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of > 500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p < 0.05).

[Hospital infection caused by enterococci. The previous use of antibiotics as risk factors in a case-control study]. / Infección hospitalaria por enterococos. El uso previo de antibióticos como factor de riesgo a través de un estudio de casos y controles.

BACKGROUND: Nosocomial infection by enterococci is of growing importance and recognition. The risk factors, morbidity and prognosis of the same were investigated by a case and control study in a third level university hospital. METHODS: One hundred patients with nosocomial infection by enterococci were compared with 100 randomly selected control patients with non enterococcic nosocomial infection. Cases and controls were taken from a series of 10,926 patients examined in search of nosocomial infection by successive cut offs of prevalence. RESULTS: The prevalence of nosocomial infection by enterococci was found to be 9.9 per 1,000 admissions. Analysis among cases and controls by the odds ratio indicated a positive association for nosocomial infection by enterococci for the following risk factors: male sex (1.8), receipt of intensive care (3.6), predisposing diseases (3.1), urinary catheter (3), abdominal-genital surgery (2.4) or nephro-urologic surgery (4.6), other previous infections (1.9) and previous exposure to antibiotics (3.7), mainly aminoglucosides (4.2). Urinary infections and those of the surgical wound predominated, 15 patients had bacteremia, with mortality related with infection being 2%, preinfection hospital stay was 34.7 days and the mean stay was of 8.3 days but these data were not statistically different in the control group. The enterococcic infections were most frequently polymicrobian (odds ratio 5.5) received worse antibiotic coverage (5.1) and presented greater number of therapeutic failures or recurrences (2.5). CONCLUSIONS: Nosocomial infection by enterococci is relatively frequent and virulent. The risk factors identified in this study are in agreement with those found in most series. The previous use of aminoglucosides was specially capable of selecting enterococci but only 13% demonstrated high level resistance to gentamicin.