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L De Rafael

Publications and source records attributed to L De Rafael.

9 recordsLinked to original sources
PubMed1999

Ampicillin-sulbactam and amoxicillin-clavulanate susceptibility testing of Escherichia coli isolates with different beta-lactam resistance phenotypes.

The activities of ampicillin-sulbactam and amoxicillin-clavulanate were studied with 100 selected clinical Escherichia coli isolates with different beta-lactam susceptibility phenotypes by standard agar dilution and disk diffusion techniques and with a commercial microdilution system (PASCO). A fixed ratio (2:1) and a fixed concentration (clavulanate, 2 and 4 micrograms/ml; sulbactam, 8 micrograms/ml) were used in the agar dilution technique. The resistance frequencies for amoxicillin-clavulanate with different techniques were as follows: fixed ratio agar dilution, 12%; fixed concentration 4-micrograms/ml agar dilution, 17%; fixed ratio microdilution, 9%; and disk diffusion, 9%. Marked discrepancies were found when these results were compared with those obtained with ampicillin-sulbactam (26 to 52% resistance), showing that susceptibility to amoxicillin-clavulanic acid cannot be predicted by testing the isolate against ampicillin-sulbactam. Interestingly, the discrimination between susceptible and intermediate isolates was better achieved with 4 micrograms of clavulanate per ml than with the fixed ratio. In contrast, amoxicillin susceptibility was not sufficiently restored when 2 micrograms of clavulanate per ml was used, particularly in moderate (mean beta-lactamase activity, 50.8 mU/mg of protein) and high-level (215 mU/mg) TEM-1 beta-lactamase producer isolates. Four micrograms of clavulanate per milliliter could be a reasonable alternative to the 2:1 fixed ratio, because most high-level beta-lactamase-hyperproducing isolates would be categorized as nonsusceptible, and low- and moderate-level beta-lactamase-producing isolates would be categorized as nonresistant. This approach cannot be applied to sulbactam, either with the fixed 2:1 ratio or with the 8-micrograms/ml fixed concentration, because many low-level beta-lactamase-producing isolates would be classified in the resistant category. These findings call for a review of breakpoints for beta-lactam-beta-lactamase inhibitors combinations.

Amoxicillin↗
PubMed1997

Usefulness of the combined IgG and IgA antibody determinations for serodiagnosis of Helicobacter pylori infection.

BACKGROUND: Serology is a good alternative, minimally invasive, diagnostic and screening test for Helicobacter pylori infection. Several immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) commercial kits have been evaluated. Information on IgA ELISAs is relatively poor, and on the combined use of IgG and IgA ELISAs very scarce. OBJECTIVE: We intended to evaluate the sensitivity, specificity and predictive values of two quantitative commercial IgG and IgA ELISAs (Helico-G and GAP, respectively) and more particularly the accuracy of their combined use. PATIENTS AND METHODS: Serum samples and gastric biopsy specimen culture findings from 400 patients were evaluated. RESULTS: The sensitivity, specificity, positive and negative predictive values of the IgG ELISA Helico-G test in detecting IgG antibodies to H. pylori were 97.2, 85.4, 98.3 and 77.8%, respectively, when compared with those of the reference method used. The corresponding findings for detection of IgA antibodies with the GAP test were 96.4, 80.5, 97.7 and 71.1%, respectively. When considering a patient infected with H. pylori when both tests were positive, the sensitivity, specificity, positive and negative predictive values were 94.1, 85.3, 98.2 and 62.5%, respectively. On the other hand, when at least one test was positive, the corresponding values were 99, 80, 97 and 94%, respectively. CONCLUSION: The IgG ELISA Helico-G and IgA ELISA GAP, taken separately, are good and reliable tests for the detection of antibodies to H. pylori. Furthermore, the combined use of both serological methods provided more useful information compared with single IgG and IgA determinations.

Adolescent↗
PubMed1995

[Course of histological lesions of the gastric mucosa after eradication of H. pylori in patients with duodenal ulcer. Initial study and 6-month follow-up].

UNLABELLED: Helicobacter pylori is the major etiologic agent of chronic active gastritis, and it may be isolated from the gastric mucosa in a high proportion of patients with duodenal ulcer. AIM: To study, in duodenal ulcer patients, the histological changes associated with H. pylori infection in gastric antrum and body, and the improvement of such lesions after eradication, at an early stage and after 6 months. METHODS: 76 patients with duodenal ulcer disease were investigated prospectively. Biopsy specimens taken by endoscopy from the duodenal bulb, antrum, body and gastric fundus were analyzed by microbiological and histological methods. A patient was considered to be H. pylori-positive when microbiology or/and histology demonstrated colonization in any of the locations. An endoscopy with biopsy samples from the antrum and gastric body was performed 1 month after therapy and 4 months later. Different therapy regimens were used: amoxicillin/clavulanic plus omeprazole or ranitidine; triple therapy; and omeprazole or ranitidine alone. RESULTS: All patients were positive by microbiology. Eradication was reached as a whole in 47% (N = 36). In those patients, in gastric antrum, rates of chronic gastritis/chronic active gastritis previous to treatment and 2 and 6 months later were 100%/96%; 38%/23% and 16%/5.6% respectively. At gastric body they were: 54%/38%; 12%/12% and 12%/5.6% respectively. A favourable histologic evolution, globally and of the acute inflammatory component, was observed 1 month after therapy (p < 0.001). Six months later, there was further improvement which did not reach a statistically significant difference compared with the results obtained at the first month. No differences were observed when eradication failed. CONCLUSION: An improvement of antral and gastric body gastritis is associated with H. pylori eradication in duodenal ulcer patients. This successful evolution is observed immediately after eradication, and it is confirmed six months after the diagnosis.

Adult↗
PubMed1990

Spontaneous peritonitis caused by Enterococcus faecium.

Three cases of spontaneous peritonitis caused by Enterococcus faecium are presented. The underlying condition was alcoholic cirrhosis in each case. This enterococcal species has never before been reported as a cause of spontaneous bacterial peritonitis. Two patients responded to therapy. The development of enterococcal peritonitis and the cases documented in the literature are briefly reviewed. Taxonomic problems with pathogenic, clinical, and therapeutic implications are discussed.

Ampicillin↗
PubMed1984

Prostatitis: are the gram-positive organisms pathogenic?

In 268 patients seen for sterility, sexual impairment or suspected prostatitis symptoms, first and midstream urine fractions, prostatic secretion and post-massage urine cultures as well as semen cultures and exfoliative cytologies of the first urine fraction and prostatic secretion were performed. Gram-positive bacteria were isolated in 160 cases. Of these, 111 (69.3%) had significant cultures (Meares and Stamey criteria). Nevertheless, when we repeated the study without previous therapy, the results could not be confirmed. This shows that Gram-positive bacteria do colonize urethra and/or prostatic ducts, but are not responsible for prostatic infection.

Adolescent↗