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Biomedical subjects

G Prats

Publications and source records attributed to G Prats.

At least 55 records · Page 3Linked to original sources
PubMed1997

Epidemiologic evidence of transmission of donor-related bacterial infection through a transplanted heart.

This study describes a patient who had fulminant infectious myocarditis as a result of methicillin-resistant Staphylococcus aureus after receiving a heart transplant from an infected donor. There was complete concordance of typing results between donor and recipient strains that were different from the 20 isolates with which they were compared. Molecular epidemiologic study provided compelling evidence that a transplanted organ can transmit a bacterial infection from the donor to the recipient.

Adult↗
PubMed1996

[Usefulness of polymerase chain reaction for the diagnosis of Bazin erythema induratum].

BACKGROUND: Erythema induratum of Bazin (BEI), is included in the group of cutaneous granulomatous lobulillar panniculitis. The aethiopathogenic association between EI and tuberculosis can not rely on the clinicohistological features of these panniculitis and M. tuberculosis has never been isolated from BEI lesions. Detection of the mycobacterial DNA by PCR on cutaneous biopsy samples would allow to confirm this association. PATIENTS AND METHODS: Fourteen patients with clinical BEI were chosen retrospectively. Seventeen lesional biopsy samples were obtained, stained with the Kinyoun carbolfuchsin acid-fast technique and haematoxylin and eosin and tested by PCR. A fragment of the IS6110 insertion sequence specific of M. tuberculosis was amplified and confirmed by digestion with Sal I restriction endonuclease. The efficiency of the procedure, the presence of inhibitory substances and the preservation of DNA were checked by PCR of the beta-actin gene. RESULTS: M. tuberculosis DNA was detected in 12 of the 17 samples tested (70.5%) which corresponded to 10 of the 14 patients (71.4%). According to beta-actin PCR results, the rate of extracted DNA was inadequate on four of the five negative biopsies. CONCLUSIONS: The results of these series suggest the probable involvement of M. tuberculosis on the BEI pathogenesis and give support to the usefulness of the PCR in the diagnosis of this pathology concerning the need of specific treatment.

Adult↗
PubMed1996

Molecular typing of Salmonella enterica serovar typhi.

The efficiencies of different tests for epidemiological markers--phage typing, ribotyping, IS200 typing, and pulsed-field gel electrophoresis (PFGE)--were evaluated for strains from sporadic cases of typhoid fever and a well-defined outbreak. Ribotyping and PFGE proved to be the most discriminating. Both detected two different patterns among outbreak-associated strains.

Bacterial Typing Techniques↗
PubMed1996

[Usefulness of DR, PGRS, and spoligotyping in the typing of Mycobacterium tuberculosis. Comparison with IS6110].

BACKGROUND: To evaluate 4 markers (IS6110, DR, PGRS and spoligotyping) to differentiate the strains of Mycobacterium tuberculosis isolated in our surroundings, most specially in those which contain a reduced number of IS6110 copies. In addition, to confirm the identity of the strains that share the same IS6110 restriction-hybridization pattern. METHODS: We selected 37 strains from a previous study: 25 had a unique IS6110 pattern and 12 grouped in 3 clusters (8 strains with 11 bands, 2 with 17 bands and 2 which shared the same six-band pattern). The PGRS and DR-RFLPs were obtained by AluI restriction and synthetic oligonucleotides specific to these sequences. The polymorphism of the DR region spacers was analyzed by spoloigotyping. For the amplification of the spacers we used the DRa and DRb primers. Detection was done hybridizing the PCR products on a membrane in which 43 specific spacers had been previously immobilized. RESULTS: Twenty-three different PGRS patterns and 18 spolygotyping patterns were obtained from 25 strains with unique IS6110 pattern. Eight patterns resulted from the 10 strains studied by DR. The 8 strains which shared an 11-band pattern, as well as the 2 strains which shared a 17-band pattern, resulted identical by the other markers. However, 2 strains which shared a 6-band pattern were different by both PGRS and DR or spoligotyping. CONCLUSIONS: 1) IS6110 resulted the most discriminative marker of all. 2) The clonality of clusters with a low number of bands has to be confirmed with alternative markers.

Bacterial Typing Techniques↗
PubMed1996

[Hemorrhagic colitis caused by verotoxigenic Escherichia coli. Presentation of 9 cases].

OBJECTIVE: To describe the clinical and epidemiological characteristics of nine patients with enteritis caused by verocytotoxin-producing E. coli O157. PATIENTS AND METHODS: Clinical data of patients was collected retrospectively, the isolated strains were tested for verotoxin production (VT) using Vero cell culture line, and presence of VT1 and VT2 gene sequences was detected using amplification techniques (PCR), biotype was also determined using twelve biochemical tests, and genomic macrorestriction profile (PFGE). RESULTS: The patients' age ranged from 11 months to 70 years. The mean duration of diarrhea was 4.7 days. All patients but one had abdominal cramps, seven of nine reported hemorrhagic stools and six had fever. Three patients were affected of haematologycal neoplasia and two of them developed hemolytic-uremic syndrome as a complication. All strains produced VT2 and two of them also produced VT1. Epidemiological link between patients has not been established. Three different biotypes had been distinguished between the nine isolated strains. All but two had different macrorestriction profiles. DISCUSSION: The results obtained showed that clinical manifestations are rather inespecific, including fever (6/9 patients) and there is high association of severe complications. The heterogeneity in PFGE results obtained confirms that the cases are not related.

Adult↗
PubMed1996

[Detection of resistance to the amoxicillin-clavulamic acid combination in Salmonella and Shigella].

PURPOSE: To study the emergence of amoxicilline/clavulanate resistance in Salmonella and Shigella. MATERIAL AND METHODS: We have studied 118 strains of Salmonella enterica and 11 strains of Shigella flexneri isolated in our laboratory along 1993. The MICs values for amoxicilline/clavulanate were determined by the E-Test method and confirmed by the standard agar dilution method. RESULTS: We have observed that 6% (7 out of 118 strains) of Salmonella enterica and 42% (5 out of 11 strains) of Shigella flexneri isolates exhibited an intermediate susceptibility or were resistant to amoxicilline/clavulanate with MICs values ranging between 16 mg/l and 32 mg/l. CONCLUSIONS: Along 1993 we have detected the emergence of an amoxicilline/clavulanate resistance in salmonellae and shigellae strains. To our knowledge this fact has not been published up to now (Medline, 1990-October 1994). We don't know the clinical importance of this fact.

Amoxicillin↗
PubMed1996

Detection of Mycobacterium tuberculosis complex DNA by the polymerase chain reaction for rapid diagnosis of cutaneous tuberculosis.

We assessed the polymerase chain reaction (PCR) technique to detect Mycobacterium tuberculosis complex DNA in 48 paraffin-embedded specimens from 32 patients with different variants of cutaneous tuberculosis, and compared the results with those of culture. A 123 bp product of the IS6110 insertion sequence specific of M. tuberculosis complex was amplified and confirmed by digestion with SalI restriction endonuclease. The time required for the procedure was 3 days. Thirty-seven samples (77.1%) were positive for M. tuberculosis complex DNA. No false positive results were obtained in nine negative controls. Of the 20 specimens tested by PCR and culture, the frequency of positivity was 90% for DNA amplification and 65% for culture. In seven cases of lupus vulgaris, the figures were 100% and 57%, respectively. In the 11 specimens culture negative or not microbiologically tested and PCR negative, evidence for tuberculous infection was provided by the correlation of various relative and absolute criteria. These results show that PCR amplification of the IS6110 insertion fragment is a rapid and accurate means for the detection of M. tuberculosis complex DNA in paraffin-embedded skin biopsies from patients with cutaneous tuberculosis, especially in paucibacillary lesions.

Adolescent↗
PubMed1996

Evaluation of an enzyme immunoassay for verotoxin detection in Escherichia coli.

Verotoxin-producing Escherichia coli strains (VTEC) cause hemorrhagic colitis and hemolytic-uremic syndrome in humans. Laboratory diagnosis by conventional methods is slow and cumbersome. The results of a new rapid enzyme immunoassay (EIA Premier EHEC) for verotoxin detection both in isolated strains and in clinical samples are presented, and they are compared with cell culture (CC) and polymerase chain reaction (PCR) techniques. Fifty-four strains have been analyzed by both EIA and PCR, and 33 by all three methods. The kit has also been evaluated for experimentally infected stool samples directly and after their enrichment on MacConkey broth. Nineteen, out of the 54 strains, were positive by EIA and 20 by PCR. The results of the 33 strains evaluated by the three techniques were coincident with one exception. The latter was uninterpretable by CC, negative by EIA and positive by PCR. The sensitivity of the kit for experimentally infected stool samples was approximately 5 x 10(7) bacteria/ml in the direct test, and 5 x 10(4) bacteria/ml after broth enrichment. EIA sensitivity and specificity were similar to those of CC and PCR. The diagnostic times were 18h for EIA, 3 days for PCR and 5 days for CC. Sensitivity, rapidity and ease of performance make this technique especially valuable for clinical diagnosis.

Animals↗
PubMed1996

[Evaluation of chromogenic medium CPS ID2 (bioMérieux) in urine cultures].

BACKGROUND: The aim of the study was to evaluate the chromogenic agar plate CPS ID2 (bioMérieux) and determine its cost-benefit ratio. METHODS: A total of 2,193 urinary sediments were processed. The urine culture was carried out in CPS ID2 agar and in cystine-lactose electrolyte deficient (CLED) agar, when needed. Identification of the microorganisms was performed following standard microbiologic procedures through biochemical tests prepared in our laboratory. The identification, from CPS ID2 agar, by direct detection in medium of four metabolic activities: beta-glucuronidase, beta-glucosidase, deaminase, and indol production, was performed following to manufacturer's instructions. RESULTS: A total of 289 urine cultures were positive, 18 were negative and 34 were contaminated samples. The identification, directly performed from the colonies detected in CPS ID2 agar, was correct in 96% of 166 Escherichia coli, in 92% of 24 Proteus mirabilis and in 97% of 38 enterococci. CPS ID2 agar exhibited 94% and 100% sensitivity and specificity, respectively in E. coli identification, 92% and 100% in P. mirabilis and 97% and 99% in Enterococcus. The use of this new media, CPS ID2, in our laboratory, implies a budgetary increment. However, if commercial galleries are used for routine identification, the cost will be reduced using this new media. CONCLUSIONS: The CPS ID2 agar allows the isolation and direct identification of the most frequent urinary tract pathogens: E. coli, P. mirabilis and Enterococcus in primary isolation medium. Using this medium, bacteriologists will be able to save time and reagents when identifying the most common uropathogens. Furthermore, the use of this medium would reduce costs in some laboratories.

Agar↗
PubMed1995

[Hemolytic-uremic syndrome caused by Escherichia coli O157:H7. Detection in direct sample of verotoxin-coding genes].

Hemorrhagic colitis is an enteritis caused by verotoxigenic strains of Escherichia coli. Conventional diagnosis requires the identification of the microorganism and the demonstration of verotoxin production. The determination of toxigenicity in isolated strains and in direct stool samples by the polymerase chain reaction (PCR) technique may simplify the diagnosis. Conventional coprocultures were performed for the detection of verotoxigenic E. coli O157:H7 from three stool samples of a patient with hemorrhagic colitis and hemolytic-uremic syndrome. The production of verotoxin was determined by cell culture and the presence of VT1 and VT2 genomic sequences by PCR. Likewise, the latter technique was applied to a direct stool sample for detection of the verotoxin codiying genes. The specificity of the amplified sequences was confirmed by enzyme restriction digestion. Escherichia coli O157:H7 was isolated in two of the three samples studied. The strains were toxigenic in the cell culture test at titers higher than 1/500 and PCR showed an amplified band of 479 pb corresponding to the VT2 codifying gene. The digestion of amplified sequences with the EcoRV enzyme led to two bands of 390 and 89 pb confirming the specificity of the results. One of the two stool samples studied directly by PCR was positive for VT2 with the result being obtained 48 hours after arrival to the laboratory. The preliminary results of this study give support to the usefulness of the polymerase chain reaction technique in the detection of verotoxin from isolated strains of Escherichia coli and in direct stool samples.

Bacterial Toxins↗