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Biomedical subjects

M Varea

Publications and source records attributed to M Varea.

13 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↗
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↗
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↗
PubMed1996

Seasonality of cryptosporidiosis in children.

The seasonal distribution of cryptosporidiosis in children in Aragón, a region in northeastern Spain, was determined. Over a period of six years (October 1988 to September 1994), 10,034 stool samples from 4,508 children with gastrointestinal symptoms were analyzed for this purpose. The age of the patients ranged from 1 month to 14 years. Cryptosporidium oocysts were identified in 87 (1.93%) patients. Prevalence was highest (6.20%) in children aged 1 to 3 years old. The prevalence was significantly higher in the autumn-winter period (October to March) than in the spring-summer period (April to September) in the whole population (2.41% vs. 1.35%, p = 0.010) and in the 1- to 3-year-old age group (8.44% vs. 3.20%, p = 0.002), but not in the other age groups. A possible relationship of this pattern to attendance at child care centres is suggested.

Adolescent↗
PubMed1996

Comparison of 2 centrifugation procedures in the formalin-ethyl acetate stool concentration technique for the detection of Cryptosporidium oocysts.

A comparison between the standard formalin-ethyl acetate (FEA) stool concentration procedure (centrifugation at 400 g for 2 min) and a modification proposed to increase the recovery of Cryptosporidium oocysts (500 g for 10 min) was performed on 73 formalin-preserved stool specimens known to be positive for Cryptosporidium. False-negative results were obtained with both methods, but the increase in centrifugation time and force resulted in the detection of a higher number of oocysts and positive samples. The modified procedure had a sensitivity significantly higher than the standard method (99% compared to 86%, P = 0.0045).

Acetates↗
PubMed1996

[Antibiotic resistance in Salmonella enterica: an increasing problem].

OBJECTIVE: To determine the evolution of the frequencies of Salmonella enterica serotypes and their resistance to antimicrobial agents. METHOD: A retrospective study of all S. enterica strains isolated from stool samples in the Hospital Clinico Universitario of Zaragoza over the period 1990-1994. RESULTS: Enteritidis was the most frequently isolated serotype (62.9%), although it showed a progressive decrease (from 76.2% in 1990 to 39.8% in 1994). Typhimurium was the serotype showing the highest resistance levels, 37.1% of its isolates being resistant to ampicillin, streptomycin, chloramphenicol and tetracyclin. There was a distinct increase in the frequency of multiresistant strains, from 9.7% in 1990 to 22.9% in 1994. Of 88 such strains, 78.4% corresponded to serogroup B, whereas only 4.5% to serogroup D. Of the antimicrobial agents traditionally considered elective, only cotrimoxazole maintained acceptable resistance levels (4.4%). Resistance to fluoroquinolones or 3rd-generation cephalosporines was not detected. CONCLUSIONS: The increasing frequency of Typhimurium, a highly resistant serotype, restrains the elective antimicrobial agents to cotrimoxazole in children and fluoroquinolones in adults. 3rd-generation cefalosporines may be a good alternative in case of therapeutic failure.

Drug Resistance, Microbial↗
PubMed1995

Evaluation of the optimal number of faecal specimens in the diagnosis of cryptosporidiosis in AIDS and immunocompetent patients.

This study determines the optimal number of faecal samples that should be examined in order to minimize the occurrence of false-negative results in the diagnosis of cryptosporidiosis using routine techniques. A total of 23,023 faecal samples from 10,870 patients submitted for parasitological examination were processed by the formalin-ethyl acetate concentration technique and stained using a modified Ziehl-Neelsen method. Cryptosporidiosis was diagnosed in 232 patients (2.13%), 44 of whom were infected by HIV, the prevalence rate in this population group being 15.54%. The increase in the number of diagnoses obtained by the examination of n and (n-1) specimens was evaluated statistically. This study found that three is the optimal number of faecal samples that should be examined when cryptosporidiosis is suspected in immunocompetent patients; whereas, only two samples are required for diagnosing this protozoosis in AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Respiratory cryptosporidiosis: case series and review of the literature.

Five case of intestinal cryptosporidiosis with pulmonary involvement in patients with AIDS are reported. The diagnosis was based on the recognition of acid-fast oocysts in sputum or aspirated bronchial material and stool specimens. Coughing and excess secretions were present in all cases. Four patients had other associated pulmonary pathogens: two Mycobacterium tuberculosis, one Mycobacterium fortuitum and one Cytomegalovirus + Pneumocystis carinii; all of them had a previous (three cases) or simultaneous (one case) diagnosis of intestinal cryptosporidiosis, presenting with diarrhoea and vomiting. In the fifth patient Cryptosporidium was the only pulmonary pathogen found in a bronchial aspirate, and the onset of diarrhoea was 1 month after respiratory detection. Fifty-seven cases of respiratory cryptosporidiosis have been reported since 1980. In 17 of them, no other pathogen was found. Diarrhoea was present in 77% of the patients, cough in 77%, dyspnea in 58%, expectoration in 54%, fever in 45%, thoracic pain in 33%.

Acquired Immunodeficiency Syndrome↗