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Biomedical subjects

F J Castillo

Publications and source records attributed to F J Castillo.

At least 19 recordsLinked to original sources
PubMed2002

Evaluation of an immunochromatographic dip-strip test for the detection of Cryptosporidium oocysts in stool specimens.

The study presented here examined the efficacy of a commercially available qualitative immunochromatographic assay for detecting Cryptosporidium oocysts in stool samples. A total of 75 samples were tested, including 50 positive for Cryptosporidium spp. by acid-fast stain, 20 positive for other parasites ( Blastocystis hominis, Endolimax nana, Entamoeba coli, Giardia lamblia, Ascaris lumbricoides, Strongyloides stercoralis and Trichuris trichiura), and five negative samples. The observed sensitivity was 98%, while specificity was 100%; the detection threshold was near 1000 oocysts/ml. Correctly diagnosed positive samples included Cryptosporidium parvum genotypes 1 and 2, whereas the single false-negative sample corresponded to a Cryptosporidium meleagridis infection.

Animals↗
PubMed2002

[Antimicrobial resistance of clinical strains of Salmonella enterica isolated in Zaragoza].

In order to identify any changes in the incidence of Salmonella enterica serotypes and their resistance to a variety of antimicrobial agents, we conducted a retrospective study of all the strains isolated from stool samples at Hospital Clínico Universitario Lozano Blesa in Zaragoza from 1997 to 2000. We observed an increase in the number of isolates of Salmonella and Campylobacter and a decrease in other enteropathogens. Enteritidis was the most frequently isolated serotype (55.2%), showing an increasing tendency (from 44.1% in 1997 to 60.6% in 2000). Hadar, glostrup and virchow showed the highest rate of resistance to nalidixic acid. Enteritidis also showed an important increase in resistance to nalidixic acid (from 17.6% in 1997 to 41.4% in 2000). Typhimurium showed the highest resistance levels to ampicillin, chloramphenicol and cotrimoxazole. No resistance to fluoroquinolones or to cefotaxime was detected, with the exception of 0.5% of the S. enteritidis strains, which showed resistance to fluoroquinolones.

Drug Resistance, Bacterial↗
PubMed2001

The eaeA gene is not found in Hafnia alvei from patients with diarrhea in Aragón, Spain.

A total of 102 Hafnia alvei clinical strains isolated from different patients with diarrhea has been tested, using polymerase chain reaction and dot-blot hybridization, for the enteropathogenic Escherichia coli attaching and effacing A (eaeA) gene to establish their role as a causative agent of diarrhea in our environment. None of them was positive for the eaeA gene. We cannot consider the eaeA gene as the virulence-associated factor implicated in the H. alvei strains isolated from diarrheal feces in our region.

Adhesins, Bacterial↗
PubMed2001

Biochemical changes in needles of Pinus radiata D. Don trees in relationship to long-term ozone exposure indices.

Ambient concentrations of ozone in Europe are high enough to cause negative effects on vegetation. Therefore, many efforts have been made to determine exposure indices and critical levels for protection of vegetation. In this context, the choice of a suitable attribute to determine the pollutant effect is of paramount importance. Until now, much of the work has been done with attributes such as biomass or growth. In the present work correlation factors have been established between biochemical parameters (peroxidase activity, ascorbate and sulfhydryl contents) of Pinus radiata trees and exposure indices of ozone. Our results show that peroxidase cannot be used as an indicator of effects of long-term exposure to ozone but still remains as an excellent indicator of short-term ozone fluctuations in the field. Ascorbate may act as an intermediate indicator responding to both short fluctuations and long-term exposures to ozone. Finally, sulfhydryl may be used as a long-term indicator in relation to the AOT (average over threshold) exposure index. Our results also point to the fact that Pinus radiata may be affected by ozone at AOT values lower than 10 ppm.h as already observed with other tree species.

Air Pollutants↗
PubMed2001

Distribution of resistance genes tet(M), aph3'-III, catpC194 and the integrase gene of Tn1545 in clinical Streptococcus pneumoniae harbouring erm(B) and mef(A) genes in Spain.

The most prevalent macrolide resistance phenotype and genotype among pneumococcal isolates was the cMLSB phenotype [erm(B) or erm(B)/mef(A)] (91.3%). We studied the distribution of other resistance genes, tet(M), catpC194, aph3'-III, in these strains, seeing evolution at work in that some strains carried different combinations of resistance determinants. The most prevalent patterns associated with resistance to erythromycin [erm(B)] were resistance to tetracycline [tet(M)] and chloramphenicol (catpC194) (48.2%) or resistance to tetracycline [tet(M)] alone (42.2%). In our isolates of Streptococcus pneumoniae there was a strong association of the erm(B) and tet(M) genes with Tn1545-related elements.

Anti-Bacterial Agents↗
PubMed2001

[Association between MLS antibiotic and tetracycline resistance genes in Streptococcus pneumoniae].

In Streptococcus pneumoniae, resistance to macrolide, lincosamide and streptogramin type B (MLS(B)) antibiotics is mediated by erm(B) and mef(A) determinants. Tetracycline resistance is always associated with resistance to minocycline and is due to the presence of the tet(M) gene. The erm(B) determinant is predominant. We demonstrated that the erm(B) gene could be present with mef(A), which is of streptococcal origin, and msr(A), which is of staphylococcal origin, this being an example of genetic promiscuity. The tet(M) determinant was associated with pneumococci harboring the erm(B) gene, while it was not associated with the strains harboring the mef(A) gene. This association is due to the fact that, in most of the cases, erm(B) and tet(M) reside in the same chromosomal conjugative transposon.

Anti-Bacterial Agents↗
PubMed2000

Astrovirus infection among children with gastroenteritis in the city of Zaragoza, Spain.

The incidence of astrovirus infection in children less than 10 years of age with gastroenteritis in the city of Zaragoza, Spain, was analysed during a 12-month period. A total of 718 stool samples obtained from 534 children were examined. In 401 samples no routinely searched for pathogenic organism was detected; these specimens were then tested for the presence of astrovirus antigens. Astrovirus was detected in the samples of 15 (5.5%) patients, a detection rate similar to that recognised for Yersinia enterocolitica and Cryptosporidium spp. All children with confirmed astrovirus infection had diarrhoea (median duration, 9 days), 11 experienced loss of appetite, 5 vomiting, and 4 fever. The incidence of astrovirus infection reported here indicates that Spanish children suffering from gastroenteritis should be routinely screened for the presence of astrovirus.

Astroviridae Infections↗
PubMed2000

[Presence of conjugative transposon Tn1545 in strains of Streptococcus pneumoniae with mef(A), erm(B), tet(M), catpC194 and aph3'-III genes].

We studied the association of MLS resistance genes (erm(B) and mef(A) with others non-MLS resistance genes: tet(M) (tetracycline and minocycline), catpC194 (chloramphenicol) and aph3'-III (kanamycin) in order to know how is selected the multiresistant in Streptococcus pneumoniae. The tet(M) and catpC194 genes were present very often in the pneumococci with the erm(B) gene but the aph3'-III was found only in four strains. Tn1545 was nearly always the responsible for the dissemination of these genes. In contrast, mef(A) was not associated with tet(M) and and catpC194 and is disseminated in a different conjugative transposon. The linkage of multiple antibiotic resistance genes on the same mobile element is of importance for public health, because the use of one antibiotic selects for the transposon which carries multidrug resistance genes.

Anti-Bacterial Agents↗
PubMed1999

Oxidative stress induced by copper in sunflower plants.

The toxic effect of copper was evaluated in sunflower plants by means of root elongation, lipid peroxidation and antioxidative enzyme activities. Plants were grown under controlled environmental conditions in hydroponic culture for two weeks and exposed to different copper concentrations for an additional week. Determinations were performed in both roots and leaves. From the results of the root elongation test, a copper concentration of 10 microM was found to be toxic for sunflower plants causing lipid peroxidation and, thus, oxidative stress. Antioxidative enzymes (peroxidase and superoxide dismutase) responded at lower, nontoxic copper concentrations.

Antioxidants↗
PubMed1999

Antioxidative defense and photoprotection in Pinus halepensis induced by Mediterranean conditions and ozone exposure.

Pigment levels and antioxidative stress-related metabolites were determined over a period of two years in Pinus halepensis to characterize the response of some plant protective processes to both environmental stresses and 03 exposure. Two-year-old-Aleppo pine seedlings were grown in open-top chambers under optimal nutrient and water conditions and exposed to different 03 levels: charcoal filtered air, non-filtered air and nonfiltered air plus 40 ppb O3 10 h/day. In summer an activation of photoprotective systems was observed since a decrease in chlorophyll levels, an increase in the carotenoid/chlorophyll ratio and SOD activation were recorded. Interestingly, the SOD activity in Pinus halepensis was highly related to low-molecular weight compounds and this relationship increased with needle age. Ozone exposure induced alterations in the activity of some antioxidant enzymes along with reductions in pigment concentrations and an activation of the xanthophyll cycle.

Antioxidants↗
PubMed1999

Visualization of hydatid elements: comparison of several techniques.

Some techniques available at our laboratory were tested for their ability to aid in the morphological diagnosis of hydatid elements (Echinococcus granulosus ["Taenia echinococcus"]) isolated from cysts in humans and sheep. Unstained, methanol-fixed hooklets were fluorescent, most starkly so under violet light (excitation filter wavelength, 405 nm; long-pass filter wavelength, 495 nm). Auramine-rhodamine and Gram procedures failed to stain hooklets. Ziehl-Neelsen stain yielded indifferent results when organisms were viewed under transmitted light but resulted in a surprisingly intense red fluorescence when organisms were viewed under green light (excitation, 546 nm; long pass, 590 nm). Wheatley trichrome stain gave better and more uniform results than fuchsin. Ryan trichrome blue stain was the best under transmitted light; hooklets stained uniformly and intensely and were easily distinguishable from the background. Very satisfactory results were also obtained with a much simpler procedure (modified Baxby technique: no fixation, steaming hot 1% safranin for 2 min, and malachite green for 30 s). Therefore, Ryan and modified Baxby stains are recommended for the examination of E. granulosus under transmitted light. For fluorescence microscopy, Ziehl-Neelsen stain under green excitation light, or violet light with no staining, is also very useful. Epifluorescence microscopy is especially convenient for examining samples concentrated by filtration, as it renders the filter pores inconspicuous.

Animals↗
PubMed1999

Hodgkin's disease: internal mammary lymph nodes relapse diagnosed by gallium-67 scintigraphy.

This article presents the case of a 62-year-old man with treated Hodgkin's disease who had internal mammary lymph nodes relapse after a complete initial response. These masses were gallium avid. These findings were explained by histologically documented Hodgkin's relapse, the first such case reported in that localization without chest wall involvement. The literature on mediastinal Hodgkin's disease and diagnostic procedures are reviewed.

Breast↗
PubMed1998

Use of a selective medium and a membrane filter method for isolation of Campylobacter species from Spanish paediatric patients.

A study was conducted to assess the value of a combination of two culture methods for isolation of Campylobacter spp. from Spanish children. Seven hundred twenty-nine diarrhoeal stool specimens from 599 patients were examined for Campylobacter spp. by culturing them on charcoal cefoperazone deoxycholate agar and on blood agar with a membrane filter. One hundred sixteen Campylobacter strains were isolated from a total of 108 specimens; 75 (64.6%) were Campylobacter jejuni, 32 (27.5%) were Campylobacter coli, 8 (6.8%) were non-typeable, and one (0.9%) was Campylobacter upsaliensis. Campylobacters were isolated from 99 positive samples using charcoal cefoperazone deoxycholate agar alone. The filtration technique alone yielded only 86 positive samples. Seven specimens yielded different Campylobacter spp. with different media. The only catalase-negative strain was recovered using the filter method. The combination of the selective medium with the filter method increased the isolation rate of Campylobacter strains by 14.1%. Isolation rates of campylobacters using the filter method were similar to those reported in European studies, in which a similar frequency of Campylobacter upsaliensis was observed. The addition of a filter method for routine laboratory isolation of campylobacters should be considered in selected age groups (in children < 10 years of age) or in areas where catalase-negative or weakly-positive Campylobacter strains may be of epidemiological significance.

Adolescent↗
PubMed1998

Fuchsin fluorescence and autofluorescence in Cryptosporidium, Isospora and Cyclospora oocysts.

Cryptosporidium parvum and Isospora belli oocysts stained with carbol-fuchsin, as in a modified Ziehl Neelsen technique, fluoresce bright red under green light (546nm). Cryptosporidium oocysts tend to fluoresce more brightly the less intensely stained they appear under transmitted light; this is not the case with Isospora. Fuchsin-stained Cyclospora cayetanensis oocysts fluoresce rather dimly, but those not taking the dye retain their typical autofluorescence. Cryptosporidium and Isospora oocysts are also autofluorescent, appearing violet under u.v. light (365 nm), and green under violet (405 nm) and blue-violet light (436 nm). Their autofluorescence does not survive the staining procedure.

Animals↗
PubMed1998

[Quinolone resistance in Salmonella enterica].

Nalidixic acid resistance is a marker of quinolone sensibility in Salmonella spp. In our laboratory we observed an increase of nalidixic acid resistant strains from 0.44% in 1990 to 13.7% in 1996. The purpose of this work was to study the evolution of nalidixic acid resistance in Salmonella spp., as well as the association with certain serotypes and the cross-resistance to others agents. A total of 1,782 isolates of Salmonella enterica were studied from fecal and blood sources over a 7-year period; 45 strains (2.52%) were resistant to nalidixic acid (MIC > 16 microgram/ml). Two isolates required 2 microgram/ml of ciprofloxacin for inhibition, while the remaining 43 strains required 1 microgram/ml. The most frequent serotypes in nalidixic acid resistant strains were the following: enteritidis (33.3%), hadar (31.11%) and virchow (15.5%). In 1996, enteritidis was the predominant serotype (13/31), and hadar serotype was found to have the greatest nalidixic acid resistance at 80% of strains. No differences of sensibility to other agents were detected between the nalidixic acid resistant group and nalidixic acid sensitive strains. This type of resistance appears regularly in uncommon serotypes such as hadar. The increasing incidence of resistant isolates in enteritidis in 1996 is of even greater concern.

Anti-Infective Agents↗