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Biomedical subjects

R Cisterna

Publications and source records attributed to R Cisterna.

At least 73 records · Page 4Linked to original sources
PubMed1993

[DNA probe for the detection of uropathogenic strains of P-fimbriated Escherichia coli].

BACKGROUND: P fimbria is one of the main factors of virulence of the uropathogenic Escherichia coli strains thus developing methods for its detection is of interest. P fimbriation may manifest through associated characteristic hemagglutination patterns. Another way of directly detecting its expression is by the PF test consisting in a specific agglutination test with latex particles which have the specific receptor of the fimbria incorporated. METHODS: The two phenotypic techniques (hemagglutination pattern using human, bovine, and sheep erythrocytes, and the PF test) were compared with colony hybridization with a specific DNA probe (pap1) in 35 strains of uropathogenic E. coli. RESULTS: Eight of the 35 strains studied were positive for the PF test with 7 strains presenting mannose-resistant agglutination to human erythrocytes without agglutinating the other erythrocytes tried. However, with hybridization with the DNA probe the number of positives was higher (25/35). CONCLUSIONS: The difference found in the number of positive strains may be due to the probe used corresponding to cluster pap, thus the use of a smaller more specific probe for fimbrial expression obtained from pap should be used given that the hybridization technique is easy to perform and is carried out in less time than phenotypic detection which requires long periods of culture prior to the test.

Animals↗
PubMed1993

[Oligonucleotide probes for the characterization of TEM-1 and TEM-2 beta lactamases in Salmonella strains].

BACKGROUND: The aim of this study was to develop molecular biology techniques as hybridization with oligonucleotide probes to characterize TEM-1 and TEM-2 beta-lactamases in strains of Salmonella spp. METHODS: Twenty seven strains of Salmonella spp. were selected. Twenty six were resistant to ampicillin due to the production of beta-lactamases enzymes of pl of 5.4 and/or 5.6 corresponding to TEM-type. Initially, they were submitted to colony hybridization with a 420 bp. TEM probe obtained from plasmid pBR322. The strains with positive signal were selected to perform colony hybridization and Southern blot with oligonucleotide probes for TEM-1 (Gln 37) and TEM-2 (Lys 37). Finally, polymerase chain reaction technique (PCR) was developed to obtain DNA. RESULTS: Only 17 out of the 26 beta-lactamase producing strains gave positive signals with the TEM intragenic probe. Experiments with the oligonucleotide probes in colony hybridization did not allow us discriminate positive from negative signals. Southern blot of DNA obtained from alkaline lysates did not work as we could not obtain any signals in the filters. To resolve these problems and to obtain enough DNA to perform Southern blot we developed PCR. This way it was able discriminate the bla-TEM-1 from the bla-TEM-2 genes. CONCLUSIONS: PCR technique plus oligonucleotide probes are a good alternative for the specific characterization of TEM-1 and TEM-2 beta-lactamases in Salmonella spp.

Ampicillin Resistance↗
PubMed1993

[Utilization of an emergency service by patients with HIV infection].

BACKGROUND AND METHODS: To know the impact of HIV infection in a hospital emergency department the health care episodes of seropositive individuals are reviewed in a retrospective study from the January 1 to March 31, 1992. Cases have been identified comparing the list of those infected by HIV with the users of the department during the period studied. RESULTS: 430 episodes in 288 patients (1.5 episodes/patient) have been included constituting 2.3% of the total. 76.4% were males, with a mean age of 29.2 years (range, 18-59) and 60.2% were evaluated the medical area. Hospital admission was indicated on 147 occasions (34.2% versus 19% of seronegatives; p < 0.001). The most frequent diagnoses were infections which were or were not associated to alteration of cellular immunity (32.8%) and complications related with the abuse of opioid substances (23.7%). CONCLUSIONS: The pathology associated to HIV infection and to the abuse of intravenous drugs constitutes a frequent problem in the emergency departments. The infectious diseases which are or are not associated to alteration in cellular immunity, complications related with the consumption of opioids and the high index of admissions are of note. Professionals carrying out health care work in this medium must be familiarized with the diagnosis and treatment of these processes.

Adolescent↗
PubMed1993

[Resistance in Haemophilus influenzae in Spain. 2d study (1990)].

AIM: To study the resistance to strains of H. influenzae simultaneously isolated during 1990 in 10 Spanish cities with this being the second multicentric study carried out in Spain. METHODS: Three hundred eight strains of H. influenzae were consecutively isolated with less than 50% being from the respiratory tract. The sensitivity by microdilution in supplement Isosensitest was studied. RESULTS: Thirty-five percent of the strains were producers of beta-lactamase which predominate among those isolated in systemic infections and specially among those from Madrid (58.78%) and Barcelona (61.8%). The strains producing beta-lactamase were more resistant to all the antimicrobials than the non producers. Five point two percent of the strains were resistant to ampicillin by non enzymatic mechanisms. Resistance to chloramphenicol is frequent (28.6%) especially among strains producing beta-lactamase, strains of ocular origin and ORL (46%) and systemic infections (74.3%). The distribution is irregular, being more frequent in Seville (66.7%) and not detectable in Barcelona. Resistance to tetracycline is also usually linked to the production of beta-lactamase and not necessarily to that of chloramphenicol. Resistance to cotrimoxazole is the most frequent (67.5%) specially in Valladolid (87.5%). Resistance to cefaclor is of 60.7% being the most frequent among those isolated from ocular processes and ORL. Only 28 strains (9.1%) were sensitive to all the antimicrobials tested. Thirty-nine percent were multiresistant. CONCLUSIONS: The authors found a slight increase in the high resistance detected in 1986. This increase was not uniform in all of Spain being significant in Madrid with producers of beta-lactamase, in Seville to chloramphenicol, to tetracycline in Bilbao and cotrimoxazole in Valencia.

Bacterial Proteins↗
PubMed1993

[Application of PCR for the detection of mutations in the genes coding for beta-lactamases].

BACKGROUND: The purpose of this study was to develop a satisfactory technique to detect punctual mutations in blaTEM genes. METHODS: The strains [E. coli HB 101 pBR322 (TEM-1), E. coli J62 RP4 (TEM-2)] were submitted to PCR with primers PL1 and PL2 which amplify the genetic region susceptible of punctual mutations. Then, we developed Southern blot and hybridization with oligonucleotide probes (GIn 37, Lys 37 y Thr 261), corresponding to first and last mutations. RESULTS: A region of 841 bp was amplified using the primers previously described. Hybridization experiments with the Thr 261 probe gave positive signal with both strains (both carry the mutation); GIn 37 only hybridized with TEM-1 and Lys 37 only with TEM-2. CONCLUSIONS: The use of primers which amplify all the region susceptible of mutations in blaTEM and oligonucleotide probes allows the specific detection of point modifications in the original genes by the use of digoxigenin-labeled oligonucleotide probes.

Adamantane↗
PubMed1993

[Diagnosis of anaerobic infection of the pleural fluid using gas-liquid chromatography].

BACKGROUND: An assessment of the efficacy of the detection of volatile and non-volatile fatty acids that are produced by microorganisms aimed at the possible diagnosis of pleural empyema. METHODS: 106 pleural fluids were examined by gas-liquid chromatography in contrast to conventional aerobic and anaerobic cultures. The sample previously prepared (1 microliter) was injected in an Hewlett-Packard 5890 chromatograph, that was equipped with a fused silica capillary column and a flame ionization detector. RESULTS: Growth of aerobic or anaerobic microorganisms was obtained in 13 (12.3%) of the samples, and volatile or non-volatile fatty acids were detected in all of them (sensitivity = 1). No growth was obtained in the 93 samples, but volatile or non-volatile fatty acids were detected in 64 (68.8%) of them (specificity = 0.31). A positive predictive value of 0.17 and a negative predictive value of 1 were obtained. Growth of anaerobic microorganisms was obtained in 9 samples (8.5%) and volatile fatty acids were detected in all of them (sensitivity = 1). Anaerobic microorganisms did not grow in 97 samples, however volatile fatty acids were detected in 2 (2.1%) of them. A positive predictive value of 0.82 and a negative of 1 were obtained. CONCLUSIONS: Referring to pleural fluid samples, the detection of volatile and non-volatile fatty acids by gas-liquid chromatography is a highly sensitive method, that may be used to quickly reject negative samples in about 30 mins. Furthermore, when anaerobic microorganisms exist, the high specificity of gas-liquid chromatography will make it possible to confirm their presence in the sample, mainly if there is a clinical suspect of anaerobic infection. Thus, the utilization of this sensitive method may also change the therapeutic behaviour.

Bacteria, Aerobic↗
PubMed1993

[Estimation of infection by Aspergillus fumigatus in mice infected experimentally by the respiratory route].

BACKGROUND: To evaluate a new chitin detection technique for the quantification of Aspergillus fumigatus infection in organs from air-borne infected mice. METHODS: Different groups of mice were air-borne infected with A. fumigatus spores. The mortality rate was studied as well as the extension of the infection by means of colony counts (UFC) and quantification of chitin . RESULTS: The inhalation of A. fumigatus spores by non-immunosuppressed mice produces a 34% mortality rate, with an initial invasion of lung tissue followed by the spleen, kidneys, heart and liver thereafter. CONCLUSION: The quantification of chitin in involved organs allowed us to estimate the degree of organ-specific fungal infections and perhaps could be an useful method for studying the pathogenesis of A. fumigatus infections.

Administration, Inhalation↗
PubMed1993

[Production of hepatitis B virus from peripheral blood lymphocytes stimulated with phytohemagglutinin].

BACKGROUND: It was studied the production of HBV from lymphocytes from peripheral blood induced with a mitogen agent as phytohemagglutinin (PHA), in patients infected by HIV. METHODS: The methodology developed included the culture of peripheral blood mononuclear cells and its induction to proliferate with PHA, in order to study the viral activity in the supernatants of the cultures by detection of HIV-Ag (ELISA), HBsAg (ELISA) and DNA-HBV (Dot-blot). RESULTS: Production of HBV in 23 out of the 42 patients included in this study, corresponding to 21 anti-HIV positive and 2 anti-HIV negative. CONCLUSIONS: Induction to proliferate lymphocytes with a mitogen agent as PHA may represent an alternative way of culture to study interactions between HIV and HBV.

Cells, Cultured↗
PubMed1992

[Chronic granulomatous disease and pulmonary nocardiosis].

A 19-years-old male was admitted for left bilobar pneumonia. All microbiologic studies in blood and in several samples obtained by bronchoscopy were negative. The patient worsened progressively despite antibiotherapy of a wide spectrum. A fine needle transparietal puncture was performed. The cultures of the sample were positive for Nocardia asteroides, a positive catalase germ. Immunologic studies initiated after this time showed negative tetrazolium nitroblue test, the results of which led to the diagnosis of chronic granulomatous disease. This disease is very infrequent and the polymorphonuclear leukocytes are genetically incapable of producing peroxides whose absence impedes lysis of the positive phagocytic catalase germs with which a histologic reaction is produced in the form of granulomas from which the name of the disease is derived.

Adult↗
PubMed1992

Vulvovaginal candidiasis refractory to treatment with fluconazole.

We present the case of an infertile patient, whose first attempt at IVF had to be postponed for 18 months due to a vulvovaginal yeast infection refractory to treatment. The main causative organism was a Candida glabrata strain resistant to all the imidazolic agents tested. The organism and the host's humoral status were studied in depth, looking for possible causes of the refractoriness to treatment.

Adult↗