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Biomedical subjects

D Domingo

Publications and source records attributed to D Domingo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Metronidazole resistance and virulence factors in Helicobacter pylori as markers for treatment failure in a paediatric population.

The eradication rate obtained using the classical triple therapy containing metronidazole, amoxicillin and bismuth citrate, was determined in 57 paediatric patients with digestive disorders, according to the susceptibility to metronidazole of the Helicobacter pylori strains (determined by agar dilution) and the cagA and vacA status (determined by PCR). Eradication was obtained in 38 out of 43 patients (88.3%) infected by H. pylori with metronidazole MIC < or = 2 mg l(-1), in 3 out of 6 patients (50%) when MIC was 4-8 mg l(-1) and in 4 out of 8 patients (50%) when MIC was > 8 mg l(-1). Among patients infected with cagA+ and cagA- strains an eradication rate of 75% (6/8) and 75% (18/24) was found, and 50% (3/6) and 80% (21/26) among vacA s1- and vacA s2-infected subjects (P > 0.05). H. pylori eradication depends on the susceptibility of the strain to metronidazole, being higher in patients infected with susceptible H. pylori. However, according to our data the cagA or vacA status was not an important factor in treatment failure in the eradication of H. pylori.

Adolescent↗
PubMed1999

cagA gene and vacA alleles in Spanish Helicobacter pylori clinical isolates from patients of different ages.

The prevalence of the cagA gene and vacA alleles in 124 Spanish Helicobacter pylori clinical isolates from patients of different ages ranging from 3 to 78 years was studied (21 patients < or = 10 years, 30 patients 11-20 years, 17 patients 21-40 years, 31 patients 41-60 years and 25 patients 61-80 years). The cagA gene and vacA s1 or vacA s2 alleles were identified by PCR from the strain. 66.9% of the isolates were cagA+ and 33.1% cagA-. vacA s1 was detected in 48.4% of the isolates and vacA s2 in 51.6%. 44.4% of patients were cagA+/vacA s1, 22.5% were cagA+/vacA s2, 4% were cagA-/vacA s1 and 29% were cagA-/vacA s2. The percentage of cagA+ isolates and the vacA s1 alleles in the different groups were as follows: 23.8% and 28.6% in 0-10 years, 40% and 30% in 11-20 years, 88.2% and 70.6% in 21-40 years, 90.3% and 70.9% in 41-60 years and 92% and 44% in the 61-78 years group. 93% (54/58) of isolates found in ulcer patients and 90.9% (10/11) of isolates from gastritis patients older than 20 years were cagA+. In patients younger than 20 years ulcer disease was rare with 60% of isolates being cagA+ (3/5) compared with 31.6% cagA+ isolates (12/38) in patients suffering from gastritis in the younger group. The prevalence of the cagA gene and vacA s1 allele increased with age, being more frequent in older patients than in younger.

Adolescent↗
PubMed1999

Bacteriostatic and bactericidal activity of ranitidine bismuth citrate in Helicobacter pylori clinical isolates.

Ranitidine bismuth citrate is a novel salt that seems to be useful in eradication of Helicobacter pylori from gastric mucosa when it is combined with antibiotics. The in vitro bacteriostatic (by MIC determination) and bactericidal (by killing curve) activity of ranitidine bismuth citrate was determined in this study. A total of 52 strains were cultured from gastric antral biopsy specimens taken at routine endoscopy and identified using standard methodology. MIC was determined by agar dilution using Mueller-Hinton agar supplemented with 7% horse blood. Killing curves were studied in 11 isolates. Ranitidine bismuth citrate at final concentrations of 1 mg/l and 8 mg/l were used. A starting inoculum of 10(4) to 10(6) CFU/ml was prepared in BHI with 10% fetal calf serum from a 48 h H. pylori broth culture. Viable colony counting was performed at 0, 2, 4, 6, 8 and 24 h. A control without the study drug was included in each experiment and treated identically. A reduction of 100 to 1,000 CFU/ml was considered bactericidal. The MIC50, MIC90 and range for ranitidine bismuth citrate was 1, 2 and 0.25-4 mg/l, respectively. At 1 mg/l it showed a bactericidal effect after 2 h in one strain, after 8 h in two and after 24 h in four strains, and four strains were not killed. At 8 mg/l it killed three strains in 2 h, one in 4 h, two in 6 h, one in 8 h and four strains in 24 h. Ranitidine bismuth citrate was active in vitro against the H. pylori clinical isolates tested (by MIC and killing curves).

Anti-Ulcer Agents↗
PubMed1998

Sorting mechanisms regulating membrane protein traffic in the apical transcytotic pathway of polarized MDCK cells.

The transcytotic pathway followed by the polymeric IgA receptor (pIgR) carrying its bound ligand (dIgA) from the basolateral to the apical surface of polarized MDCK cells has been mapped using morphological tracers. At 20 degreesC dIgA-pIgR internalize to interconnected groups of vacuoles and tubules that comprise the endosomal compartment and in which they codistribute with internalized transferrin receptors (TR) and epidermal growth factor receptors (EGFR). Upon transfer to 37 degreesC the endosome vacuoles develop long tubules that give rise to a distinctive population of 100-nm-diam cup-shaped vesicles containing pIgR. At the same time, the endosome gives rise to multivesicular endosomes (MVB) enriched in EGFR and to 60-nm-diam basolateral vesicles. The cup-shaped vesicles carry the dIgA/pIgR complexes to the apical surface where they exocytose. Using video microscopy and correlative electron microscopy to study cells grown thin and flat we show that endosome vacuoles tubulate in response to dIgA/pIgR but that the tubules contain TR as well as pIgR. However, we show that TR are removed from these dIgA-induced tubules via clathrin-coated buds and, as a result, the cup-shaped vesicles to which the tubules give rise become enriched in dIgA/pIgR. Taken together with the published information available on pIgR trafficking signals, our observations suggest that the steady-state concentrations of TR and unoccupied pIgR on the basolateral surface of polarized MDCK cells are maintained by a signal-dependent, clathrin-based sorting mechanism that operates along the length of the transcytotic pathway. We propose that the differential sorting of occupied receptors within the MDCK endosome is achieved by this clathrin-based mechanism continuously retrieving receptors like TR from the pathways that deliver pIgR to the apical surface and EGFR to the lysosome.

Animals↗
PubMed1998

In polarized MDCK cells basolateral vesicles arise from clathrin-gamma-adaptin-coated domains on endosomal tubules.

Human transferrin receptors (TR) and receptors for polymeric immunoglobulins (pIgR) expressed in polarized MDCK cells maintain steady-state, asymmetric distributions on the separate basolateral and apical surfaces even though they are trafficking continuously into and across these cells. The intracellular mechanisms required to maintain these asymmetric distributions have not been located. Here we show that TR and pIgR internalize from both surfaces to a common interconnected endosome compartment that includes tubules with buds coated with clathrin lattices. These buds generate vesicles that carry TR to the basolateral border. The lattices contain gamma-adaptin and are dispersed by treatment with brefeldin A (BFA). Since BFA treatment abrogates the vectorial trafficking of TR in polarized MDCK cells, we propose that the clathrin-coated domains of the endosome tubules contain the polarized sorting mechanism responsible for their preferential basolateral distribution.

Adaptor Protein Complex gamma Subunits↗
PubMed1998

In vitro activity of ebrotidine, ranitidine, omeprazole, lansoprazole, and bismuth citrate against clinical isolates of Helicobacter pylori.

The aim of this study was to determine the in vitro activity of ranitidine, ebrotidine, bismuth citrate, omeprazole, and lansoprazole against 113 clinical isolates of Helicobacter pylori cultured from gastric biopsies. An agar dilution method using Mueller-Hinton agar plus 7%, horse blood, an inoculum of 10(6) cfu/spot, and incubation in a CO2 incubator for 2 to 5 days was used. The minimum inhibitory concentrations for 50 and 90% of the isolates tested, respectively, were as follows: ranitidine, 1024 and 1024 mg/l; ebrotidine, 64 and 256 mg/l; bismuth citrate, 1 and 4 mg/l; omeprazole, 16 and 16 mg/l; and lansoprazole, 1 and 1 mg/l. Ebrotidine was more active than ranitidine, and lansoprazole was the most active compound against the Helicobacter pylori isolates tested.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1998

High-level mupirocin resistance among Spanish methicillin-resistant Staphylococcus aureus.

Twelve strains of methicillin-resistant Staphylococcus aureus with high-level resistance to mupirocin were studied. The MIC of methicillin was 16 to 128 mg/l and the MIC of mupirocin > or = 512 mg/l. All of the isolates carried a plasmid of about 30 MDa, and one strain lost resistance to mupirocin when the plasmid was cured. Three different resistance patterns were found: six strains were resistant to ciprofloxacin, kanamycin, and 10 mg/l of cadmium sulfate; two strains were resistant to these agents as well as to gentamicin, erythromycin, clindamycin, mercury chloride, and ethidium bromide; and four strains were resistant to the previously named agents as well as to rifampicin and tetracycline. The use of this valuable topical antibiotic, especially in long-term-care facilities, should be monitored to avoid dissemination of resistance.

Anti-Bacterial Agents↗
PubMed1998

Study of the combination of ranitidine bismuth citrate and metronidazole against metronidazole-resistant Helicobacter pylori clinical isolates.

The in-vitro activity of a combination of ranitidine bismuth citrate (RBC) and metronidazole against metronidazole-resistant Helicobacter pylori strains (MIC > or = 8 mg/L) was evaluated by agar dilution chequerboard and killing curve methods. Twenty-five metronidazole-resistant strains were used in the chequerboard method, using Mueller-Hinton agar plus 7% lysed horse blood, an inoculum of 10(6) cfu/spot and incubation in a 10% CO2 atmosphere at 37 degrees C for 3-5 days. Synergy was defined as a fractional inhibitory concentration (FIC) index of < or = 0.5, partial synergy as 0.5 < FIC < or = 1, indifference as 1 < FIC < or = 4 and antagonism as FIC > 4. For nine strains, killing curves were constructed for metronidazole and RBC individually and in combination at 1 x MIC. The number of viable colonies was counted at time 0 and after 2, 4, 6, 8 and 24 h; the combination was defined as synergic if it produced a decrease of > or = 2 log10 cfu/mL compared with the most active single agent. Metronidazole MICs ranged from 8 to 128 mg/L and RBC MICs from 0.125 to 4 mg/L. The minimum FIC ranged from 0.28 to 1 and the maximum FIC from 1 to 1.25. When RBC and metronidazole were combined, all the metronidazole-resistant H. pylori strains revealed partial (68%) or total (32%) synergy. Five out of the nine strains also exhibited synergy at 4, 6 or 8 h incubation when tested by the killing curve method although three other strains exhibited no synergy. In the last strain, a 2log10 decrease in the initial number was observed with RBC alone or combined with metronidazole.

Anti-Bacterial Agents↗
PubMed1998

[In vitro activity of trovafloxacin in 238 respiratory pathogens].

The in vitro activity of trovafloxacin against 238 clinical isolates obtained from respiratory specimens were compared with ciprofloxacin. Fifty-four Haemophilus influenzae, 58 Streptococcus pneumoniae, 40 Moraxella catarrhalis, 21 Streptococcus pyogenes, 25 Klebsiella pneumoniae and 40 Staphylococcus aureus (21 methicillin resistant and 19 methicillin susceptible) were studied. The MIC was determined following NCCLS recommendations. Ciprofloxacin and trovafloxacin MIC90 was 0.016 mg/l and 0.016 mg/l for H. influenzae, 4 mg/l and 0. 25 mg/l for S. pneumoniae, </=0.008 mg/l and </=0.008 mg/l for M. catarrhalis, 0.5 mg/l and 0.064 mg/l for S. pyogenes, 0.064 mg/l and 0.25 mg/l for K. pneumoniae, 16 mg/l and 0.5 mg/l for methicillin-resistant S. aureus and 2 mg/l and 0.032 mg/l for methicillin-susceptible S. aureus. According to this data, trovafloxacin showed better in vitro activity than ciprofloxacin in the Gram-positive pathogen studied and similar activity against the Gram-negatives tested.

Anti-Infective Agents↗
PubMed1998

[Use of the polymerase chain reaction (PCR) for the diagnosis of Helicobacter pylori infection in pediatric patients].

BACKGROUND: Several direct or non direct methods may be used to detect H. pylori infection. A molecular method, PCR with ureA primers, was used in this study in 43 gastric biopsies obtained from paediatric patients with digestive symptomatology and the results were compared with those obtained by histology and culture. METHODS: Culture and histological stain were performed from gastric biopsies taken at routine endoscopy following standard methodology. A PCR with specific primers for the ureA gene was applied and the 411 pb fragment detected by agarose gel electrophoresis. RESULTS: From the 43 gastric biopsies, 21 were positive by culture (48.8%), 25 by histology (58.1%) and 29 by PCR (67.4%). In 30 biopsies (69.7%) PCR results were in good agreement with the reference method (histology and/or culture). In 7 biopsies the PCR was positive (16.3%), although the reference method was negative and in 6 (13.9%) the PCR was negative being positive the histology (5 samples) or histology and culture (1 sample). CONCLUSIONS: PCR shows the highest positive percentage among the methods used. The use of as many methods as possible in the H. pylori infection, increases the diagnosis of the infection.

Adolescent↗
PubMed1997

Evolution of resistance to metronidazole and clarithromycin in Helicobacter pylori clinical isolates from Spain.

The aim of this study was to determine the frequency of resistance to amoxycillin, tetracycline, metronidazole and clarithromycin in 282 Helicobacter pylori clinical isolates from Spain and to evaluate the evolution of resistance over the five years of this study. The overall percentage of resistance was 19.9% for metronidazole and 3.5% for clarithromycin. Resistance to metronidazole rose from 9% in 1991 to 21.6% in 1995, although 33.3% resistance was found in 1993. Clarithromycin resistance was not detected in 1991 or 1992 and the rate was 4%, 3.4% and 4.4% in 1993, 1994 and 1995, respectively. No amoxycillin or tetracycline resistance was found.

Adolescent↗
PubMed1996

[The assessment of functional status in hospitalized elderly patients: the Plutchik scale].

BACKGROUND: To study the usefulness of the Plutchik Scale to measure functional capacity in daily activities of hospitalized elderly patients. PATIENTS AND METHODS: A sample of 300 patients stratified by age and sex (111 male and 189 female), mean age 81 years, hospitalized in the Geriatric Unit, was selected from all the patients admitted to our Unit along the year 1994 (n = 974, mean length of stay in acute beds 15 days, in convalescent beds 57 days, total 19 days). Scores of patients in the Plutchik Scale, Katz Activities of Daily Living and Barthel ADL Index were obtained. Ninety seven of the subjects were rated by two independent observers. RESULTS: The kappa statistic of interrater reliability in Plutchik Scale scoring was high (0.807). There was a good correlation between the three instruments at cut-points for autonomy/dependence: 0.824 for cut-points 4/5 in Plutchik Scale and 2/3 in Katz Activities of Daily Living; 0.846 for cutpoints 4/5 in Plutchik Scale and 55/60 in Barthel ADL Index (p < 0.01). The coefficient alpha (Cronbach) in Plutchik Scale was 0.876 and the standardized alpha 0.868, which reflect that the Plutchik Scale is internally consistent. By factor analysis one factor was obtained explaining 58% of the variance. The factor showed the highest correlation with "washing/dressing" (0.861) and lowest with "vision" (0.349). CONCLUSIONS: The Plutchik Scale is a good instrument for measuring functional capacity in hospitalized elderly patients.

Activities of Daily Living↗
PubMed1996

In vitro activity of omeprazole in combination with several antimicrobial agents against clinical isolates of Helicobacter pylori.

An agar dilution checkerboard method was used to evaluate the in vitro activity of omeprazole combined with clarithromycin, amoxicillin, and ceftibuten, respectively, against clinical isolates of Helicobacter pylori. Mueller-Hinton agar plus 5% horse blood, an inoculum of 10(6) cfu/ml, and incubation of 72 h in a CO2 atmosphere were used. With the omeprazole and clarithromycin combination, synergism was observed in 51.5% and partial synergism in 39.3% of 33 strains; with omeprazole and amoxicillin, synergism was observed in 3% and partial synergism in 60.6% of 33 strains; and with omeprazole and ceftibuten, synergism was observed in 33.3% and partial synergism in 50% of 24 strains. Antagonism between omeprazole and each antibiotic was exhibited in 0%, 6.1%, and 4.1% of these groups of strains, respectively. Of the antibiotic combinations tested, omeprazole plus clarithromycin exhibited synergism (partial or total) in the highest percentage of strains.

Amoxicillin↗