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R Cisterna

Publications and source records attributed to R Cisterna.

At least 55 records · Page 3Linked to original sources
PubMed1995

Emergence of resistance to beta-lactam agents in Pseudomonas aeruginosa with group I beta-lactamases in Spain.

The contribution of induction and stable derepression of chromosomal class I beta-lactamases to beta-lactam antibiotic resistance was studied in clinical isolates of Pseudomonas aeruginosa collected from patients treated with beta-lactam antibiotics. Multiple isolates from the same patient were characterized by O-serotyping as a primary screen, combined with pyocin typing. Sonicated extracts of cells were assayed for chromosomal and plasmid-mediated beta-lactamases by isoelectric focusing and cloxacillin inhibition studies. The specific beta-lactamase activity, basal and induced, with cefoxitin was determined to differentiate strains with inducible or derepressed production of the enzyme. Beta-lactamase induction was performed in each strain against the beta-lactam agents used in the therapy of each patient. The observations showed that induction against older penicillins such as penicillin, amoxicillin, and amoxicillin/clavulanate resulted in a moderate to strong increase in beta-lactamase activity, whereas the results obtained with first-generation cephalosporins varied with the beta-lactam agent tested. Third-generation cephalosporins were weak inducers of beta-lactamases, and their use as therapy preceded the appearance of strains that produce chromosomal group I beta-lactamases constitutively. These strains showed a remarkable reduction in sensitivity to ureidopenicillins, carboxipenicillins, third-generation cephalosporins, and monobactams, but not to carbapenems.

Anti-Bacterial Agents↗
PubMed1995

Five-year survey of cefotaxime resistance in Spain.

During 1991-1995 a Spain collaborative study group surveyed the resistance to cefotaxime both in community as well as in hospital isolates of bacteria. The isolates tested during the study period of 5 years were 813, 875, 3631, 3184, and 3050 strains, respectively. Antimicrobial activity of cefotaxime was assayed by broth or agar microdilution, in accordance with criteria of the National Committee of Clinical Laboratory Standards (NCCLS). Cefotaxime resistance included 2.5% of all isolates: 2.6% Enterobacteriaceae, 1.7% Streptococcus pneumoniae, 0.5% Haemophilus influenzae, 0.0% Haemophilus spp., and 0.0% Moraxella catarrhalis. The overall incidence of resistance to cefotaxime decreased fro member of Enterobacteriaceae from 3.6% in 1991 to 2.5% in 1995. The incidence of resistance varied with the species and was highest in Enterobacter and in Citrobacter freundii.

Bacterial Infections↗
PubMed1994

Detection of hepatitis B virus DNA and determination of surface antigen expression in peripheral blood mononuclear cells from patients with AIDS.

The polymerase chain reaction (PCR) was used to analyze the presence of hepatitis B virus (HBV) DNA in serum and peripheral blood mononuclear cells (PBMCs) from 20 patients with AIDS with and without conventional HBV serological markers. DNA sequences of HBV were detected in PBMCs from 13 patients, nine of whom were positive for anti-HBc only and four of whom were also positive for anti-HBs. When PBMCs from patients were activated in culture with phytohemagglutinin, the presence of HBsAg could be detected in the culture supernatants from four of 13 patients with HBV DNA in their PBMCs; for two of the four, HBV DNA could also be detected in the culture supernatant after DNA amplification. It was observed that HBV DNA sequences found in PBMCs can be reactivated by mitogen stimulation in some HIV-1 infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Detection of human immunodeficiency virus type 1 by PCR before seroconversion in high-risk individuals who remain seronegative for prolonged periods.

HIV-1 seronegative patients at high risk for HIV infection were followed up. In 1990 PCR was positive for HIV DNA sequences in samples of 17 seronegative patients who continued to report for surveillance of HIV infection. There was clear evidence of seroconversion in four of these 17 seronegative patients, while in one patient an indeterminate result for HIV was repeatedly obtained in different samples. The other 12 patients continue to be seronegative without any evidence of HIV infection except the presence of provirus in peripheral blood mononuclear cells. It is important to apply the PCR technique together with tests to detect other virological and immunological markers, in order to identify seronegative carriers and thus avoid HIV transmission by them.

Adult↗
PubMed1994

In vitro activity of biapenem against beta-lactamase producing Enterobacteriaceae.

The activity of biapenem was compared with that of imipenem and cefotaxime against 108 strains of beta-lactamase producing Enterobacteriaceae. Biapenem and imipenem were very active, inhibiting 90% of the strains at a concentration of 0.5 microgram/ml. Both carbapenems were very active against plasmidic beta-lactamase producers, with MIC90s below 1 microgram/ml. However, the MIC90 of biapenem for cephalosporinase producers was 1 microgram/ml. Against strains producing extended-spectrum beta-lactamases, biapenem exhibited better activity against TEM-type producers (MIC90 0.25 microgram/ml) than against SHV-type producers (MIC90 0.5 microgram/ml). Overall, the in vitro antibacterial activity of biapenem is similar to that of imipenem.

Cefotaxime↗
PubMed1994

Multicenter evaluation of a fully automated screening test, VIDAS HIV 1 + 2, for antibodies to human immunodeficiency virus types 1 and 2.

A multicenter study was done to evaluate the sensitivity, specificity, and efficiency of a new screening test for the simultaneous detection of human immunodeficiency virus type 1 and 2 (HIV-1 and HIV-2) antibodies. The VIDAS HIV 1 + 2 (bioMérieux, Marcy l'Etoile, France) is a fully automated enzyme-linked fluorescent immunoassay that uses synthetic peptides from immunodominant regions of gp41 of HIV-1 and gp36 of HIV-2 as antigens. A total of 2,984 samples were evaluated with this system in six different laboratories, and the results were compared to those obtained with other enzyme-linked immunosorbent assays. The VIDAS HIV 1 + 2 assay showed a very good performance in terms of sensitivity (100%) and specificity (99.6%), requiring minimal manipulation and short incubation time (32 min) to give results similar to or better than those of the other enzyme-linked immunosorbent assays used for screening.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

[Detection of virulence factors using DNA probes in uropathogenic strains of Escherichia coli].

BACKGROUND: There are several bacterial determinants that contribute to the onset of urinary tract infection by E. coli. The present study focuses on some of the virulence factors considered to be most important, as P fimbriae, the siderophore aerobactin and bacterial capsule, which were studied among 123 uropathogenic E. coli strains isolated from outpatients from the Basque Community. METHODS: Virulence factors were detected using Molecular Biology techniques, namely DNA hybridization to specific probes prepared in our laboratory. RESULTS: When probe pap2, specific for fimbrial adherence was used, 36.5% of the strains showed positive hybridization, and 66 and 73% of the strains hybridized to probes for aerobactin and common capsule region, respectively. CONCLUSIONS: We believe that this technology provides a very useful tool for rapid and easy screening of strains harbouring different virulence factors. Nevertheless, the fact that these methods detect genetic determinants that are not always being expressed must be borne in mind.

Bacterial Adhesion↗
PubMed1994

Detection of circulating antigens in the diagnosis of acute toxoplasmosis.

Using an enzyme-linked immunosorbent assay, we have found circulating antigens of Toxoplasma gondii in three models of murine toxoplasmosis: mice infected with trophozoites of the RH strain (acute toxoplasmosis), the Beverley strain (subacute toxoplasmosis), and the T626 strain (chronic toxoplasmosis). Circulating antigens were detected 48 hr after infection in the mice infected with the RH strain, and all mice had antigenemia by the fourth day. In those infected with the Beverley strain, circulating antigens were detected from the second day after inoculation until the end of the study, with a peak (71% of the infected mice) on day 10. Of those infected with the T626 strain, 40% had antigenemia at 13 days after infection. The detection of circulating antigens in serum is directly related to the presence of toxoplasmosis in the acute phase in the three models studied and, therefore, may prove very useful in the rapid diagnosis of this disease.

Acute Disease↗
PubMed1994

[Incidence of lymphoid neoplasms in patients with HIV infection].

BACKGROUND: The incidence, histologic type and clinical characteristics of the lymphoid neoplasms found in patients with HIV infection may be influenced by environmental factors. These characteristics were herewith investigated in the authors medium. METHODS: The medical records of the patients in whom lymphoma was diagnosed were reviewed studying the usual clinical, epidemiological, histological and biological variables. RESULTS: Fourteen patients: 10 with non Hodgkin lymphomas and four with Hodgkin disease were studied. The prevalence was 5% of the total number of patients with AIDS. Seven patients of the former and none of the latter had previously uncomplicated HIV infection. The following histologic types were observed: two Burkitt lymphoma, 4 undifferentiated lymphomas and 4 immunoblastic lymphomas among the non Hodgkin cases and two with mixed cellularity, one lymphocytic depletion and one undetermined among the Hodgkin's cases. Eighty percent of the patients with non Hodgkin lymphoma and 50% of the patients with Hodgkin disease presented a IV-B stage. The median of survival was 2.5 months (limits 1-8) for non Hodgkin cases and 11 months (limits 1-36) for the patients with Hodgkin disease. CONCLUSIONS: The prevalence of lymphoma in patients with AIDS in the authors' medium is similar to that referred in other studies although a high proportion of Hodgkin's disease may be found.

Adult↗
PubMed1994

[Serological parameters for the diagnosis and follow-up of toxoplasmosis. Experimental models].

BACKGROUND: Toxoplasmosis is a disease of increasing incidence. Its laboratory diagnosis is difficult, specially in acute toxoplasmosis. The data obtained in experimental models attempting to distinguish between acute and chronic toxoplasmosis by the simultaneous study of four serological tests: IgM and IgG antibodies, circulating antigens (CA) and antigens present in immune complexes (IC) are reported. METHODS: The evolution of IgM and IgG antibodies, CA and IC was followed in 3 murine models in acute, subacute and chronic toxoplasmosis, compared with the use of the ELISA technique. RESULTS: Acute toxoplasmosis is characterized by the presence of CA and IC in 100% of the individuals at high concentrations with IgM and IgG only being detectable at low concentrations. In subacute and chronic toxoplasmosis the response to IgG antibodies (100% in animals) is prominent, with detection of IgM being variable and the detection of CA and IC being reduced to the phase considered as acute. CONCLUSIONS: The detection of IgM and IgG antibodies, circulating antigens and immune complexes may be of great usefulness in the differentiation of acute, recently acquired or chronic toxoplasmosis.

Animals↗
PubMed1994

[Varicella pneumonia in the adult].

In the adult, the primary infection by the varicella-zoster virus acquires an unusual severity due to several complications, the most frequent of them being pneumonia. The authors analyze the clinical, epidemiological, serological and radiological data of the only two cases of varicellous pneumonia in the adult at a general hospital during the past 5 years. They highlight as the main characteristics: easiness of diagnosis, dissociation between clinical and radiological signs and the excellent therapeutical response to the early administration of intravenous Aciclovir. They comment as well the risk factors of this complication and the criteria for hospitalization.

Acyclovir↗
PubMed1994

[Bacteremia caused by Haemophilus influenzae with special reference to its relation to HIV infection].

BACKGROUND: The association between infection by Haemophilus influenzae and infection by the human immunodeficiency virus (HIV) has been clearly demonstrated. However, some characteristics of this association still remain poorly defined. METHODS: The medical records of all adult patients admitted to a general hospital over a period of four years with blood cultures positive for Haemophilus influenzae were reviewed. Patients were grouped according to whether HIV infection or no evidence of HIV infection existed. Clinical and epidemiologic data were collected and compared. The main features of data corresponding to seropositive patients are reported. RESULTS: Of a total of 29 cases of bacteremia by Haemophilus influenzae, 19 were diagnosed in adults: 5 in patients with HIV infection and 14 in patients without HIV infection. Over the following 18 months one additional case was reported. The incidence (calculated in cases per 100,000 people/year) was 1.9 in the general population, 1.5 in adults, 70 in adults with HIV infection and 360 in AIDS patients. All the cases diagnosed in adults below the age of 30 years were reported in HIV carriers. Five of the 16 (31%) H. influenzae strains tested were resistant to ampicillin, with a significant difference being found between those isolated from HIV positive patients (4/5) and from HIV negative patients (1/11). No patient with HIV infection died during the episode. But five of the HIV negative adults died. CONCLUSIONS: HIV infection seems to be frequent risk factor for bacteremia by Haemophilus influenzae. It should always be considered on diagnosis in adults under the age of 30. Likewise, the high probability of resistance to ampicillin should also be taken into account for the empiric treatment.

Acquired Immunodeficiency Syndrome↗