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Biomedical subjects

G Prats

Publications and source records attributed to G Prats.

At least 73 records · Page 4Linked to original sources
PubMed1995

Detection and characterization by immunoblot analysis of potentially diagnostic Leishmania infantum polypeptides in human visceral leishmaniasis.

Humoral immune responses were studied in 53 sera from 18 patients with visceral leishmaniasis by immunoblot analysis. Sera from visceral leishmaniasis patients recognized antigens with molecular weights ranging from < 14 kDa to more than 100 kDa. Bands ranging between 49 and < 14 kDa were the most specific. The 40, 33 and 17 kDa antigens were recognized by 90%, 79% and 79% of the patients sera, respectively. Sera from one patient with Chagas' disease identified 8 of 11 antigens of the specific region. Treatment with periodate eliminated the cross-reaction in three of these antigens (40, 29, 26 kDa). The study of serial sera collected from the different patients showed a decrease in intensity or dissappearance in some of the diagnostic bands, particularly the 17 kDa band. The band of 17 kDa seems to be useful to study the clinical evolution, for post-treatment control and also for epidemiologic purposes. (It has been identified in 7% of control sera from endemic areas.) Immunoblot could be a valuable tool in the diagnosis of visceral leishmaniasis, being more sensitive and specific than other serologic tests.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Enteroinvasive Escherichia coli. Pathogenesis and epidemiology].

Enteroinvasive Escherichia coli (EIEC) is an intestinal pathogen causing enteritis, with a similar pathogenic mechanism to that of Shigella, which causes an epithelial invasion of the large bowel leading to inflammation and ulceration of the mucosa. The patients often develop the symptoms of bacillary dysentery. The EIEC strains are atypical in their biochemical reactions and may ferment lactose late or not at all, are lysine decarboxilase negative, and non motile. In addition, most EIEC strains express somatic antigens which are either strongly related or identical to Shigella antigens. EIEC invasion is mediated by a large plasmid (140 MDa) coding for the production of several outer membrane proteins involved in invasiveness. These strains have been isolated with some regularity in South America, the Extreme Orient, and Eastern Europe. In Spain the incidence of enteroinvasive E. coli is extraordinarily low (0.2%), the serogroup O124 being the most frequently isolated. EIEC enteritis has been associated to sporadic cases occurring in travellers. Occasional outbreaks related to ingestion of contaminated water or food and person to person have been reported.

Enteritis↗
PubMed1995

[Resistance to imipenem in Enterobacter aerogenes].

BACKGROUND: In June, 1993, an Enterobacter aerogenes strain was isolated in the Hospital de la Creu Roja from Hospitalet de Llobregat (Barcelona), which was resistant against all beta-lactams, including imipenem. Since is unusual in Enterobacter sp. to isolate imipenem resistant strains, we decided to study its resistance mechanism. METHODS: To study the E. aerogenes 174004/H resistance mechanism beta-lactamase isoelectrofocalization was performed together with the determination of kinetic constants in order to characterize the beta-lactamase, and a polyacrylamide gel electrophoresis in order to observe the profile. RESULTS: The strain of E. aerogenes 174004/H exhibits a chromosomic beta-lactamase with a pI higher than 9.2 and a decrease in an outer membrane protein of 42 kDa, probably a porine. CONCLUSIONS: E. aerogenes 174004/H resistance against imipenem is due to an hyperproduction of a chromosomic beta-lactamase with a pI higher than 9.2 and to a 42 kDa decrease of an outer membrane protein expression.

Bacterial Outer Membrane Proteins↗
PubMed1995

Escherichia coli capsular polysaccharide and spontaneous bacterial peritonitis in cirrhosis.

Spontaneous bacterial peritonitis (SBP) is a frequent and severe complication of cirrhosis. Escherichia coli is the most frequent bacterium isolated in this condition. The presence of capsular antigens, mainly the K1 capsular polysaccharide, has been associated with invasiveness in E coli infections. Capsular serotypes of E coli causing SBP were determined in 37 cirrhotic patients. Twenty-seven strains were encapsulated (72.9%), 9 of them (24.3%) with K1 capsular polysaccharide, and 10 were nonencapsulated. Patients with encapsulated E coli showed a significantly higher incidence (92.5% vs. 50%; P < .01) and number of complications per patient (1.9 +/- 1.1 vs. 0.8 +/- 1.0; P < .01) than patients with nonencapsulated strains. Although mortality was higher in patients with encapsulated strains (44.4% vs. 20%), the difference did not reach statistical significance. Considering patients infected by encapsulated strains, the incidence of complications and mortality were similar in patients with or without K1 strains. These data suggest that the presence of encapsulated strains could have a prognostic significance in SBP caused by E coli in cirrhotic patients.

Aged↗
PubMed1995

[Comparison of the automatized BacT/ALERT blood culture incubation and reading system and a conventional system].

BACKGROUND: The aim of the present study was to compare the BacT/ALERT blood culture automatic management and reading system (Organon Teknika) with a conventional, nonautomatic technique (DUO, Bio-Mérieux). METHODS: 1,405 blood cultures were parallel compared. 263 of them were positive; out of these, 148 were considered as indicative of septicaemia, 38 of doubtful clinical significance and 77 as accidental contaminations. RESULTS: No differences were detected between both systems neither in the number of isolates obtained nor in the kind of microorganisms recovered or in the number of false-positive or false-negative readings. The conventional system detected 28% of significant isolates during the first 24 hours, reaching 77% after 48 hours; whereas the BacT/ALERT system had detected 57% of significant isolates after 12 hours, reaching 82% after 24 hours (p < 0.001). CONCLUSIONS: The results obtained and the automatization of the BacT/ALERT system appoint it as a firm candidate to be included into the Clinical Microbiology laboratory routine.

Adult↗
PubMed1995

In vitro activity of E-4868, a new fluoroquinolone with a 7-azetidin ring, compared with ciprofloxacin, ofloxacin and fleroxacin.

E-4868, (-)-7[3-(R)-amino-2-(S)-methyl-1-azetidinyl]-1-(2,4- difluorophenyl)-1,4-dihydro-6-fluoro-4-oxo-3-quinolinecarboxylic acid, is a new fluoroquinolone with a 7-azetidin ring substituent. The in vitro activity against clinical isolates was compared with that of ciprofloxacin, ofloxacin and fleroxacin. In general, activity of E-4868 against aerobic and facultative anaerobic Gram-negative bacilli was equal to or slightly less active than ciprofloxacin with the exception of Morganella morganii and Proteus spp., E-4868 MIC90, 1 and 0.5 microgram/ml, respectively. E-4868 activity was two- to eight-fold higher than ciprofloxacin against Gram-positive cocci. For anaerobic species, E-4868 activity was comparable to that of ciprofloxacin, although against the Bacteroides fragilis group E-4868 was four-fold more active than ciprofloxacin.

Anti-Infective Agents↗
PubMed1994

[Application of molecular epidemiology techniques in the study of food poisoning caused by Staphylococcus aureus].

BACKGROUND: The use of molecular epidemiology techniques has provided better knowledge as to the clonal organization of bacterian populations and thus allows better follow up of epidemics. An alimentary toxiinfection in a Barcelona school produced by Staphylococcus aureus was analyzed by the combination of epidemiologic, phenotype and genotype markers with the aim of determining the source of the alimentary contamination. METHODS: Nine strains of Staphylococcus aureus isolated in 6 food manipulators and 3 patients were studied with the following markers: biotype, antibiotype, phagotype, plasmid profile, polymorphism of the size of the restriction fragments of total DNA and ribotype. RESULTS: Epidemiologic study of the strains analyzed showed that both the phenotype markers and the plasmid profile are thecniques of little discriminatory value. The only clearly discriminatory technique used was ribotyping which defined 3 clones in the 9 strains of Staphylococcus aureus studied. CONCLUSIONS: Molecular study of isolated strains of Staphylococcus aureus was able to identify the causal origin of the alimentary toxiinfection in one of the 6 food manipulators studied.

Bacterial Typing Techniques↗
PubMed1994

Risk factors for infection by Pseudomonas aeruginosa in patients with ventilator-associated pneumonia.

OBJECTIVE: to investigate the epidemiology of infection by Pseudomonas aeruginosa in patients with ventilator-associated pneumonia (VAP). DESIGN: prospective clinical study. SETTING: a medical-surgical ICU in a university hospital. PATIENTS: we followed-up 568 mechanically ventilated patients and 83 episodes of VAP with etiologic diagnosis in 72 patients were retained for analysis. RESULTS: Ps. aeruginosa was isolated in 22 (26.5%) episodes in 18 patients. Of these episodes 7 were directly responsible for death. Using logistic regression analysis, the risk of VAP due to Ps. aeruginosa was increased in patients with chronic obstructive pulmonary disease (relative risk (RR) = 29.9, 95% confidence interval (CI) = 4.86-184.53), a mechanical ventilation period longer than 8 days (RR = 8.1, 95% CI = 1.01-65.40) and prior use of antibiotics (RR = 5.5, 95% CI = 0.88-35.01). CONCLUSIONS: patients with VAP and these factors have a greater risk of infection by Ps. aeruginosa and empirical therapy for these episodes should include anti-pseudomonal activity until etiologic diagnosis is established.

Adult↗
PubMed1994

Nosocomial bacteremia in a medical-surgical intensive care unit: epidemiologic characteristics and factors influencing mortality in 111 episodes.

OBJECTIVE: To analyze the epidemiology and factors influencing mortality of ICU-acquired bacteremia. DESIGN: Prospective clinical study. SETTING: A medical-surgical ICU in an university hospital. PATIENTS: We recorded variables from 111 consecutive ICU-acquired episodes for a 3-year period. RESULTS: The attack rate was 1.9 episodes per 100 patient-days. The commonest isolates were coagulase-negative staphylococci, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Intravascular catheters were the most frequent source of infection. Overall mortality was 31.5%, and 65.7% of all deaths were directly attributable to infection. Bacteremia from intra-abdominal, lower respiratory tract or unknown origin were associated with a poor prognosis. A logistic regression analysis defined intraabdominal origin (p = 0.01, OR = 15.7) and presence of shock (p = 0.04, OR = 3.3) as independently influencing the risk of death. No significant differences were found for the remaining variables studied. CONCLUSIONS: Epidemiology and etiology of ICU-acquired bacteremia does not differ seriously in respect to nosocomial bacteremia among unselected populations, although it is associated with a greater incidence and overall mortality. Presence of shock is the most important modificable variable affecting the outcome.

Bacteremia↗
PubMed1994

[Properties of a cephalosporinase produced by Proteus penneri inhibited by clavulanic acid].

P. penneri produces an inducible cephalosporinase, as many Enterobacteriaceae. Nevertheless this betalactamase is susceptible to clavulanic acid which is an exception also encountered for P. vulgaris. The authors studied the enzyme produced by P. penneri 14HBC resistant to cefotaxime (MIC 16 mg/l) isolated in Spain in 1992. This betalactamase of isoelectric point 6.65 hydrolyzes first generation cephalosporins, amoxycillin and poorly ticarcillin as it occurs for all cephalosporinases. However, this enzyme hydrolyzes strongly oxyimino-cephalosporins: cefuroxime, cefotaxime, cefepime, cefpirome as it occurs with extended-spectrum betalactamases. Cephamycins and imipenem are not substrates. Clavulanic acid has a very good affinity for this betalactamase which is inactivated progressively. These properties are similar to those of the enzyme of P. vulgaris Ro104 of isoelectric point 8.3 which, contrarily to other cephalosporinases, belongs to the structural Ambler's class A.

Anti-Bacterial Agents↗
PubMed1993

Etiology of traveller's diarrhea in Spanish travellers to developing countries.

A cohort of 337 Spanish travellers to developing countries is presented. They all consulted us for traveller's diarrhea (TD). Bacteriological, parasitological and virological examinations were performed. A bacterial cause was found in 61.65% of travellers. Toxigenic and classical pathogenic Escherichia coli strains were the main bacterial agents. In comparison with other studies, Spanish travellers harboured Y. enterocolitica and EPEC organisms as a cause of TD. G. lamblia and E. histolytica were the most frequently isolated protozoa. Helminths were found in only 9 patients. No rotavirus infections were diagnosed. Previous antibiotic treatment had been taken by 161 patients. The percentage of isolated enteropathogens was similar in travellers who had previously taken antibiotic treatment and those who had not.

Adolescent↗
PubMed1993

Polymicrobial bacteremia in critically ill patients.

OBJECTIVE: To characterize the epidemiology of polymicrobial bacteremia (PMB) among critically ill patients. DESIGN: Prospective clinical study. SETTING: University medical center. PATIENTS: All patients with positive blood cultures in a medical-surgical ICU. MEASUREMENTS: PMB represents 8.4% of all true bacteremia in our ICU. Most of these patients were postoperative but none had malignancies or significant immunodepression. Over three-quarters of the episodes were nosocomial. No significant differences in factors associated with PMB were found when they were compared with a cohort of 154 monomicrobial episodes. Enterobacteriaceae were the most common organisms. Intravascular devices (42.8%) were the most common source of PMB, followed by intra-abdominal origin (21.4%). The overall mortality was 7.1%, a lower rate than has previously been described. CONCLUSIONS: We suggest catheter replacement in patients who develop PMB and improving techniques of catheter maintenance in order to reduce its incidence.

Adult↗
PubMed1993

Increased resistance to quinolone in Catalonia, Spain.

From 1989 to 1991, the level of resistance to ciprofloxacin in our hospital increased from 0.47% to 6.7% in opportunistic Enterobacteriaceae, from 9.9% to 16% in Pseudomonas aeruginosa and from 8.27% to 31.8% in Campylobacter jejuni-coli. We also observed an increase in quinolone consumption from 1.1 in 1989 to 1.5 defined daily doses per 1000 inhabitants per day in 1991.

Anti-Infective Agents↗