PubMed Health⌕ Search

Biomedical subjects

M López-Brea

Publications and source records attributed to M López-Brea.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1999

[Primary testicular tumor].

OBJECTIVE: To report a case of primary germ cell testicular tumor that spontaneously remitted after metastasizing to the retroperitoneum, leaving histologically characteristic lesions of a fused tumor. The characteristic testicular ultrasound findings that permitted the diagnosis are described. METHODS/RESULTS: A 21-year-old male consulted for a retroperitoneal mass. The testes were normal on palpation. The testicular ultrasound showed a hyperechoic area with an acoustic shadow suspected as being a tumoral cicatrix. The histological analysis after orchidectomy revealed a mixed non-seminomatous germ cell tumor. CONCLUSIONS: Testicular ultrasound evaluation should be performed on all patients with retrosperitoneal germ cell tumor and normal testes on palpation. In the case described, there was good correlation between the ultrasound and the histological findings.

Adult↗
PubMed1999

[In vitro activity of beta-lactam agents and beta-lactamase inhibitors in clinical isolates of Acinetobacter baumannii].

Acinetobacter is a Gram-negative coccobacillus frequently associated with nosocomial infections, especially pneumonia in patients using mechanical ventilators in ICUs. Many of the clinical isolates of Acinetobacter baumannii are now resistant to most antibiotics, including the betalactams, making these infections difficult to treat. We compared the in vitro activity of betalactam agents (ampicillin, piperacillin and ticarcillin), betalactamase inhibitors (clavulanic acid, sulbactam and tazobactam) alone and in combination with betalactam agents (amoxicillin-clavulanic acid, ampicillin-sulbactam, piperacillin-tazobactam and ticarcillin-clavulanic) against 156 clinical isolates of A. baumannii using an agar dilution method. In general, we observed a low susceptibility to the betalactam agents tested (ampicillin: 1.9% susceptibility; piperacillin: 10.2%; ticarcillin: 19.8%). We did not observe a significant reduction of the MIC in the combination of betalactam agents and betalactamase inhibitors; only ampicillin/sulbactam showed a high antimicrobial activity (84.6% compared to 14.1%, 37.8% and 33.9% for amoxicillin-clavulanic acid, piperacillin-tazobactam and ticarcillin-clavulanic acid, respectively). Sulbactam was the only betalactamase inhibitor which showed good in vitro activity, with a low MIC(50) and MIC(90) (8 and 32 mg/l, respectively) similar to ampicillin/sulbactam (2 and 16 mg/l, respectively). Sulbactam could be a good therapeutic alternative for the treatment of multiresistant A. baumannii infections.

Acinetobacter↗
PubMed1999

[Relationship between antimicrobial susceptibility and virulence factors in Helicobacter pylori clinical isolates].

The aim of this study was to determine the relationship between the antibiotic susceptibility and different virulence factors among Helicobacter pylori clinical isolates. One hundred and forty-five strains were isolated from biopsy cultures obtained from adult patients. Antimicrobial susceptibility to amoxicillin, clarithromycin, metronidazole and tetracycline were tested using an agar dilution method. cagA and iceA genes and s1 and s2 alleles of vacA were studied by polymerase chain reaction. A group of patients had been previously treated for H. pylori infection. We found a resistance rate of 28.7% and 16.5% to metronidazole and clarithromycin, respectively. We did not find any resistance to amoxicillin or tetracycline. The cagA gene and s1 allele were detected in 86.3% and 65.2% of the strains. One hundred and two (71.3%) strains were iceA+. cagA+ strains showed lower percentages of resistance to antibiotics, as did vacA s1 and iceA+ strains. The role of lower rates of resistance to clarithromycin and metronidazole in more virulent H. pylori strains may have favorable effects in their eradication in patients infected with these strains.

Adult↗
PubMed1999

[In vitro activity of piperacillin-tazobactam against Klebsiella pneumoniae clinical isolates, producers or not of extended spectrum beta-lactamases].

The aim of this study was to determine the in vitro activity of piperacillin-tazobactam against 81 clinical isolates of Klebsiella pneumoniae. The clinical specimens were processed according to standard microbiological procedures and 81 K. pneumoniae isolates were identified using MicroScan Panels following the manufacturer's recommendations. A double disk diffusion method was applied to detect extended spectrum betalactamases (ESBL) (43 isolates were positive and 38 were negative). Minimum inhibitory concentrations (MIC) were determined by an agar dilution technique using Mueller-Hinton. The following antibiotics were studied: piperacillin with 4 mg/l of tazobactam, amoxicillin-clavulanic acid in a 2:1 proportion, cefotaxime, ceftriaxone, cefepime, imipenem and meropenem. The MIC(90) were 16/4 mg/l for piperacillin-tazobactam, 16/8 for amoxicillin-clavulanic acid, 16 for ceftriaxone, 16 for cefotaxime, 4 for cefepime, 0.25 for imipenem and 0.032 for meropenem in ESBL-positive strains. In ESBL-negative strains the MIC90 were as follows: 4/4 mg/l for piperacillin-tazobactam, 8/4 for amoxicillin-clavulanic acid, 0.064 for ceftriaxone, 0.125 for cefotaxime, 0.125 for cefepime, 0.125 for imipenem and 0.016 for meropenem. All betalactams showed excellent in vitro activity against ESBL non-producer K. pneumoniae. Moreover, piperacillin-tazobactam and both carbapenems showed good in vitro activity against EBSL-producer K. pneumoniae.

Drug Therapy, Combination↗
PubMed1999

[Relationship between antimicrobial susceptibility and virulence factors in Helicobacter pylori clinical isolates]

The aim of this study was to determine the relationship between the antibiotic susceptibility and different virulence factors among Helicobacter pylori clinical isolates. One hundred and forty-five strains were isolated from biopsy cultures obtained from adult patients. Antimicrobial susceptibility to amoxicillin, clarithromycin, metronidazole and tetracycline were tested using an agar dilution method. cagA and iceA genes and s1 and s2 alleles of vacA were studied by polymerase chain reaction. A group of patients had been previously treated for H. pylori infection. We found a resistance rate of 28.7% and 16.5% to metronidazole and clarithromycin, respectively. We did not find any resistance to amoxicillin or tetracycline. The cagA gene and s1 allele were detected in 86.3% and 65.2% of the strains. One hundred and two (71.3%) strains were iceA+. cagA+ strains showed lower percentages of resistance to antibiotics, as did vacA s1 and iceA+ strains. The role of lower rates of resistance to clarithromycin and metronidazole in more virulent H. pylori strains may have favorable effects in their eradication in patients infected with these strains.

Journal Article↗
PubMed1998

A multicenter randomized Phase II trial of granulocyte-colony stimulating factor-supported, platinum-based chemotherapy with flexible midcycle cisplatin administration in patients with advanced ovarian carcinoma. PSAMOMA Cooperative Group, Spain.

BACKGROUND: The purpose of this study was to analyze whether the addition of granulocyte-colony stimulating factor (G-CSF) to platinum-based combination chemotherapy could increase platinum dose intensity and response rates and decrease hematologic toxicity in patients with advanced epithelial ovarian carcinoma. METHODS: Patients with untreated advanced ovarian carcinoma (International Federation of Gynecology and Obstetrics [FIGO] Stage IIC-IV) were treated after maximum debulking surgery with cyclophosphamide, 750 mg/m2, and carboplatin, 350 mg/m2, on Day 1 plus cisplatin, 75 mg/m2, on Day 14 when clinically indicated (adequate bone marrow and renal function). Patients were randomized to receive chemotherapy alone (Arm A) or chemotherapy supported with G-CSF (5 microg/kg subcutaneously on Days 2-13; Arm B). RESULTS: Between November 1993 and April 1995, 80 patients were included. Seventy-eight patients were evaluable for dose intensity calculations. Both groups were well matched with regard to age, Eastern Cooperative Oncology Group performance status, histopathologic subtype, tumor grade, FIGO stage, and residual tumor after surgery. The dose intensities calculated in mg/m2/week for cyclophosphamide and carboplatin were similar in both groups; however, the dose intensity of cisplatin was higher in Arm B (5.7 mg/m2 vs. 10.3 mg/m2). The occurrence of Common Toxicity Criteria Grade 3-4 neutropenia was less common in the G-CSF arm (55% vs. 7.7%). Response rates (52% vs. 68%) and pathologic complete responses (32% vs. 25%) were similar in both groups. CONCLUSIONS; The addition of G-CSF to this platinum-based chemotherapy regimen in patients with advanced ovarian carcinoma resulted in a modest increment in platinum dose intensity and appeared to reduce the incidence of Grade 3-4 neutropenia.

Adult↗
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

Carbapenem resistance mediated by beta-lactamases in clinical isolates of Acinetobacter baumannii in Spain.

Four patients colonized/infected with carbapenem-resistant strains of Acinetobacter baumannii are described. The first patient had a decubitus ulcer infection and had been on intravenous imipenem for 50 days. Two other patients, from whom Acinetobacter baumannii was isolated from urine, were hospitalized in the same ward as the first patient. The fourth patient had been mechanically ventilated in the intensive care unit for 4 month and had nosocomial pneumonia. He had been on intravenous meropenem for 1 month. Minimum inhibitory concentrations (MICs) of imipenem (128 mg/l) and meropenem (> 128 mg/l) were the same for the isolates from the first three patients, and all of these isolates had the same repetitive extragenic palindromic polymerase chain reaction (rep-PCR) pattern. The MICs of carbapenems were lower for patient 4's isolate, which also had a different rep-PCR pattern. Beta-lactamases that hydrolyzed imipenem were detected in all four isolates; isoelectric points were 8.6-7.7 in the first three isolates and 6.8-7 in the fourth isolate.

Acinetobacter↗
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↗