PubMed Health⌕ Search

Biomedical subjects

E J Perea

Publications and source records attributed to E J Perea.

At least 91 records · Page 5Linked to original sources
PubMed1991

Effect of antimicrobial agents on the uptake of ofloxacin and its optically active isomer (-)-ofloxacin by human polymorphonuclear leucocytes.

The effect of several antimicrobial agents, active against Gram-positive cocci, anaerobes or fungi on the intracellular penetration of ofloxacin and its optically active isomer (-)-ofloxacin into human polymorphonuclear leucocytes (PMNs) was studied. In the presence of therapeutic extracellular concentrations of these drugs, both ofloxacin and (-)-ofloxacin reached high intracellular concentrations (cellular to extracellular ratio (C/E greater than 3). Ofloxacin and (-)-ofloxacin uptake by PMNs was higher when cells were stimulated with opsonized zymosan (C/E greater than 5). It is concluded that none of the antimicrobial agents studied significantly affected the uptake of both quinolones by human PMNs.

Anti-Bacterial Agents↗
PubMed1991

Kinetics of adherence of mucoid and non-mucoid Pseudomonas aeruginosa to plastic catheters.

The adherence of six non-mucoid and three mucoid strains of Pseudomonas aeruginosa to polyvinyl chloride (PVC), polyurethane (PU) and siliconised latex (SL) was evaluated by a radiometric method and scanning electronmicroscopy. Initially greater numbers of mucoid than non-mucoid strains adhered to all three materials. Hydrophobic non-mucoid strains adhered more efficiently than hydrophilic strains. Numbers of adherent non-mucoid P. aeruginosa cells increased with time, reaching a peak, which was different for each strain, at 1-4 h for PU, 4 h-2 days for SL and 2-3 days for PVC; thereafter a gradual decrease was observed, maximal and final values of adherence being higher with PVC and SL than with PU. Adherence of mucoid strains increased with time in 3-5 days, until a steady state was reached. We conclude that although non-mucoid strains of P. aeruginosa initially colonise plastic surfaces better than mucoid strains, mucoid strains also persist on these surfaces.

Bacterial Adhesion↗
PubMed1991

Effect of plastic catheter material on bacterial adherence and viability.

The kinetics of adherence of single isolates of Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa and Escherichia coli to catheters made of polyvinyl chloride (PVC), Teflon, siliconised latex, polyurethane and Vialon was evaluated by a radiometric assay. Radiolabelled bacteria (10(8) cfu/ml) were incubated in vials containing 1-cm lengths of catheter for up to 3 days. The peak of maximal adherence to each biomaterial was reached after 24 h for P. aeruginosa and after 72 h for the other strains. Bacterial adherence to PVC and siliconised latex was significantly higher (2-6 times; p less than 0.05) than to the other biomaterials for all the strains. The lowest values of adherence were observed with polyurethane and Vialon for the staphylococci but with Teflon for E. coli and P. aeruginosa. Bacterial viability and growth was evaluated in eluates obtained from incubation of segments of each catheter in buffer for 24 h. None of the eluates affected the viability of the staphylococci. However, all of them, significantly increased the growth of E. coli and P. aeruginosa with the exception of the eluate from siliconised latex, in which the inoculum count was reduced to an undetectable level for E. coli. We conclude that bacterial adherence to catheters may depend in part on the nature of the biomaterial and that certain substances eluted from the catheters may affect the viability and growth of different micro-organisms.

Bacterial Adhesion↗
PubMed1991

Sexually transmitted diseases in homosexual males in Seville, Spain.

BACKGROUND AND METHODS: The absence of any official statistics on the prevalence of STD in homosexual men in Spain induced us to carry out a prospective study of new homosexual patients who consulted the STD Clinic of the School of Medicine in Seville, between January 1988 and December 1989. The aim of the study was to determine the prevalence of symptomatic and asymptomatic infections in this group of patients. RESULTS: 1805 patients were seen during the study period; 318 patients were homosexual of whom 309 agreed to participate in the study. Of the 309 homosexual men, 108 (35%) had symptoms and the remaining 201 (65%) were asymptomatic. In the symptomatic group the diagnoses were: syphilis 28 (25.9%); urethritis 40 (37%) (of these 40, 11 had Neisseria gonorrhoeae, five had Chlamydia trachomatis, five had Ureaplasma urealyticum, one had Herpes simplex virus and in 18 no pathogen was detected); genital herpes seven (6.4%). Eleven (10%) had concomitant infections. The following infections were found in the asymptomatic group: syphilis 23 (11.4%), N gonorrhoeae six (3%), C trachomatis two (1%), Herpes simplex virus one (0.5%). Antibodies against HIV were detected in 30 (9.6%) of the total group. CONCLUSIONS: Sexually transmitted diseases are common amongst homosexual men in Seville and many of these are asymptomatic.

Adult↗
PubMed1991

Effect of preincubation of Pseudomonas aeruginosa in subinhibitory concentrations of amikacin, ceftazidime and ciprofloxacin on adherence to plastic catheters.

The effect of preincubation of Pseudomonas aeruginosa in subinhibitory concentrations (1/4 x minimum inhibitory concentration) of amikacin, ceftazidime and ciprofloxacin on the expression of surface hydrophobicity and adherence to polyvinyl chloride, siliconized latex and polyurethane was evaluated. None of the antimicrobials significantly altered the expression of surface hydrophobicity. Subinhibitory concentrations of amikacin did not significantly reduce the adherence of P. aeruginosa to any of these 3 biomaterials. A significant inhibition of the adherence of polyvinyl chloride and siliconized latex but not to polyurethane was induced by both ceftazidime (p less than 0.05 to p less than 0.01 in different times) and ciprofloxacin (p less than 0.01). The effect of ceftazidime was present only for the first 4 h of bacteria-biomaterial interaction, whereas that of ciprofloxacin persisted throughout the study period (72 h).

Amikacin↗
PubMed1991

Effect of ampicillin/sulbactam on human polymorphonuclear leukocyte function.

The effect of ampicillin and sulbactam on the interaction in vitro of human polymorphonuclear leukocytes (PMN) with Staphylococcus aureus was examined. The exposure of a non-penicillinase-producing S. aureus strain to one fourth the MIC of ampicillin but not of sulbactam significantly increased the uptake of bacteria by human PMN. This effect was also observed when bacteria were exposed to the MIC0.25 of different combinations of ampicillin and sulbactam (2/1, 1/1, 1/4, 1/8 and 1/32). These effects were not observed when a penicillinase-producing strain was used. The production of superoxide and hydrogen peroxide radicals by human PMN was not affected by the presence of these antimicrobials. Ampicillin and sulbactam, neither alone nor in combination, showed intracellular activity against S. aureus within human PMN.

Ampicillin↗
PubMed1991

[Effect of miocamycin and erythromycin on the activity of human neutrophils against Staphylococcus aureus].

We evaluate the effect of two macrolide drugs (miocamycin and erythromycin) on human neutrophil cells (PMNs) against S. aureus strains. We studied: a) S. aureus pre-treatment effect, using subinhibitory concentrations of the two drugs, on its phagocytosis by human PMN's; b) effect of the drugs on superoxide production by PMN's; c) intracellular activity of the two drugs against S. aureus. Prior treatment of S. aureus with subinhibitory concentrations (25% of the MIC) increases significantly the phagocytosis of opsonized bacteria by human PMN's. Using non-opsonized bacteria, the registered effect was only statistically significant for miocamycin. Pre-incubation of human PMN's with 1, 10 and 25 mg/L concentrations of each drug did not influence superoxide production of the cells. Both drugs showed slight intracellular activity against S. aureus inside human PMN's, although this only achieves statistically significant difference with higher concentrations (25 mg/L) of miocamycin. In summary, both drugs influence directly human PMN's phagocytosis of S. aureus, changing the opsonic requirements of the microorganism. At therapeutic levels, neither erythromycin nor miocamycin hampered phagocytic and bactericidal mechanisms of human PMN's. At higher concentration, miocamycin showed good intracellular activity against S. aureus.

Erythromycin↗
PubMed1991

[Antimicrobial sensitivity of 402 strains of Neisseria gonorrhoeae isolated in 7 Spanish cities].

To study N. gonorrhoeae resistance in Spain. We evaluate 402 strains consecutively isolated in 7 Spanish cities (Barcelona, Bilbao, Madrid, Murcia, Seville, Valencia and Valladolid). The MIC to 9 antimicrobial agents was determined by agar-dilution (DST) method. We found a high incidence (15.7%) of penicillinase producer strains (NGPP). Most (53.3%) of all non-NGPP strains showed reduced sensitivity to penicillin and 1.5% of the strains had chromosomally mediated resistance. All NGPP strains and 90% of non-NGPP strains showed reduced sensitivity to tetracycline (MIC greater than 0.23 mg/l). We did not found any strain with high-level tetracycline resistance. MIC90 for the other drugs tested were: erythromycin, 0.125 mg/l; spectinomycin, 16 mg/l; cefoxitin, 2 mg/l; cefuroxime 0.06 mg/l; ceftriaxone 0.0037 mg/l; ofloxacin 0.06 mg/l and ciprofloxacin, 0.0018 mg/l. NGPP are very prevalent in Spain. Most of these strains had chromosomally mediated resistance to penicillin and tetracycline. We did not found resistance to other antimicrobial agents.

Bacterial Proteins↗
PubMed1991

[Effect of subinhibitory concentrations of beta-lactams on the production of slime, surface hydrophobicity and adhesion of Staphylococcus epidermidis].

The activity of subinhibitory concentrations of oxacillin, imipenem, cefalotin, cefuroxime, cefotaxime and amoxycillin-clavulanic acid upon slime production, surface hydrophobicity and polystyrene adherence of S. epidermidis was evaluated. Slime production and polystyrene adherence of three Staphylococcus epidermidis strains was assessed using test tube (safranin stained film) or in microtiter plate. The surface hydrophobicity was determined using a biphasic system (water/p-xylene). Using one-half and one-quarter of MIC for all antibiotics tested, a reduction in slime production and polystyrene adherence was observed in all three strains used. Regarding surface hydrophobicity, in one of the strains used we have observed a rise in surface hydrophobicity values as compared to control strains whenever one-half of MCI was used for all six antimicrobial agents and also with one-quarter of amoxicillin-clavulanate MCI. Subinhibitory MCI of all six antibiotics tested inhibits slime production and adherence of Staphylococcus epidermidis. This inhibitory effect is not related to changes in surface hydrophobicity.

Anti-Bacterial Agents↗
PubMed1991

[Evolution of the sensitivity of Bacteroides group fragilis at the Sevilla University Hospital (1983-1987)].

The evolution of antimicrobial susceptibility of Bacteroides fragilis over a five year period is described. We have studied 30 selected strains isolated each year at the University Hospital of Sevilla (total: 150 strains). We did not find any resistant strain to chloramphenicol, metronidazole or imipenem. Resistance to piperacillin (8%) and cefoxitin (13%) remain constant over the study period. Resistance to cefmetazole, cefotaxime, mezlocillin, ofloxacin, clindamycin and moxalactam ranges from 24% to 37%. A rise in the percentage of resistant strains to ticarcillin (from 17% to 30%) and ceftizoxime (from 0% to 40%) was also seen during the study period. Bacteroides thetaiotaomicron was the overall more resistant species, and B. fragilis the more sensitive.

Bacteroides↗
PubMed1990

Effect of plastic catheters on the phagocytic activity of human polymorphonuclear leukocytes.

The effect of five kinds of plastic catheters (polyvinyl chloride, Teflon, polyurethane, Vialon and siliconized latex) on the phagocytic and bactericidal function of human polymorphonuclear leukocytes was evaluated. In the presence of the polyvinyl chloride, Teflon and siliconized latex catheters, superoxide radical production by polymorphonuclear leukocytes was significantly inhibited. The effect of the siliconized latex catheter was presumably mediated by products eluted from the catheter into the medium, since the incubation of polymorphonuclear leukocytes in eluates obtained from the incubation of this catheter in buffer induced a similar inhibitory effect. This phenomenon was not observed with polyurethane or Vialon catheters. Neither the catheters evaluated nor their eluates affected the uptake of opsonized Staphylococcus aureus by human polymorphonuclear leukocytes. It is concluded that the polyvinyl chloride, Teflon and siliconized latex catheters used in this study could impair the respiratory burst of human polymorphonuclear leukocytes.

Catheterization↗
PubMed1990

Effect of three plastic catheters on survival and growth of Pseudomonas aeruginosa.

The effect of polyvinylchloride (PVC), polyurethane (PU) and siliconized latex (SL) catheters on the survival and growth of six non-mucoid and three mucoid strains of Pseudomonas aeruginosa was evaluated. Pseudomonas aeruginosa (1 x 10(8)) was incubated in PBS alone (control) or with 30 1-cm length segments of each catheter and the number of viable microorganisms was determined after 8 h, 1, 2, 5, 7 and 10 days. The presence of PVC catheters significantly favoured the survival and growth of non-mucoid strains in comparison to the control (P less than 0.05 at 5 days, P less than 0.01 at 7 days and thereafter); a similar result was observed with SL catheters (P less than 0.05 at 2 days, P less than 0.01 at 5 days and thereafter). No differences were observed with PU catheters. The number of mucoid microorganisms decreased with time in all controls and suspensions containing segments of catheter, but non-mucoid revertants appeared and quickly increased in the presence of PVC and SL (but not PU) catheters. Eluates of PBS previously containing PVC or SL segments induced a 100- to 500-fold increase in the growth of a non-mucoid strain in comparison with PBS alone. It is concluded that some plastic catheters can release substance(s) that favour the viability of P. aeruginosa.

Bacterial Adhesion↗
PubMed1990

Ofloxacin concentrations in tissues involved in respiratory tract infections.

The literature on the penetration of ofloxacin from blood to respiratory tissue and secretions in patients is reviewed. In patients with acute purulent exacerbations of chronic bronchitis ofloxacin has a Cmax value in sputum of 2.7 mg/l after a 400 mg oral dose, 6.1 mg/l after 600 mg and 6.3 mg/l after 800 mg. Penetration from blood to sputum varied from 80 to 100%. The concentration of ofloxacin in bronchial aspirate, 1 to 6 h after a single oral dose of 400 mg, varied between 1.1 and 4.5 mg/l. The ratio between simultaneous mean bronchial aspirate and serum concentrations ranged between 0.53 in the second hour and 0.92 in the fourth hour. Ofloxacin concentrations in bronchoalveolar lavage fluid following an oral dose of 200 mg twice daily for at least four days amounted to 8.3 mg/l with a corresponding serum concentration of 1.7 mg/l five hours after the last dose. The distribution ratio between lavage fluid and serum was 4.9. The lung tissue penetration of ofloxacin after a dosage of 200 mg twice daily, reached a mean tissue plasma concentration ratio of 3.5 +/- 0.4 for healthy tissue and 3.9 +/- 0.4 for diseased tissue. Ofloxacin reaches high intracellular concentrations in polymorphonuclear leucocytes, alveolar macrophages, epithelial cells and fibroblasts. It is likely that these concentrations will have a sustained inhibitory and bactericidal activity against most potential respiratory pathogens including: Haemophilus influenzae, Branhamella catarrhalis, Gram-negative bacilli, Staphylococcus aureus, Legionella pneumophila, Chlamydia spp. and Coxiella burnetti.

Bronchi↗
PubMed1990

Uptake and intracellular activity of an optically active ofloxacin isomer in human neutrophils and tissue culture cells.

The penetration of an optically active ofloxacin isomer [(-)-ofloxacin] into human neutrophils and different tissue culture cells (HEp-2, McCoy, MDCK, and Vero) was studied and compared with that of ofloxacin by a fluorometric assay. The cellular-to-extracellular-concentration ratios (C/E) of (-)-ofloxacin were always higher than 6, significantly greater than those of ofloxacin at extracellular concentrations of 5 and 10 mg/liter. The penetration of (-)-ofloxacin and ofloxacin was doubled when neutrophils were stimulated by phorbol myristate acetate but not affected after ingestion of opsonized Staphylococcus aureus. The C/E ratios of (-)-ofloxacin and ofloxacin for different tissue culture epithelial cells and fibroblasts were lower than those of neutrophils but still higher than 2. Both compounds produced a significant reduction in viable intraphagocytic S. aureus during 3 h of exposure to antimicrobial agents. We conclude that (-)-ofloxacin appears to reach higher intracellular concentrations than ofloxacin, remaining active inside the neutrophils.

Cells, Cultured↗
PubMed1990

Antibiotic resistance, plasmid profile, auxotypes and serovars of Neisseria gonorrhoeae strains isolated in Sevilla (Spain).

The antibiotics resistance pattern, the plasmid profile, the auxotypes and serotypes of 116 Neisseria gonorrhoeae clinical isolates obtained in one year were examined. The incidence of penicillinase producing (PPNG) strains was 12% (14 strains). The most frequent plasmid pattern was the combination of 4.5, 2.6 and 24.5 MDa plasmids. The conjugative plasmid of 24.5 MDa showed a high prevalence (32% of the total strains), and almost all the PPNG strains harboured this plasmid. The strains with the 4.5 MDa plasmid belonged to the auxotypes Pro-, Zero and Pro-Hyx-Ura-, whereas that with the 3.2 MDa plasmid was of auxotype Pro-Hyx-His-. The serotypes Aedih/Arst (WI serogroup) and Bak/Bropt, Back/Bropyt and Bak/Bropyt (WII/III serogroup) were predominant.

Drug Resistance, Microbial↗
PubMed1990

Effect of azithromycin, roxithromycin and erythromycin on human polymorphonuclear leukocyte function against Staphylococcus aureus.

The effect of three macrolides (azithromycin, roxithromycin and erythromycin) on the interaction in vitro of human polymorphonuclear leukocytes (PMNs) with Staphylococcus aureus was examined. The exposure of S. aureus to 0.25 MIC of roxithromycin and erythromycin but not of azithromycin significantly increased the uptake of opsonized bacteria by human PMNs. The preincubation of PMNs with 1, 10 and 25 mg/l of the three antimicrobial agents did not affect either the uptake of S. aureus or the superoxide radical production by human PMNs. At these same concentrations the three agents showed slight but not significant intracellular activity in PMNs against S. aureus. It is concluded that treatment of S. aureus with subinhibitory concentrations of roxithromycin and erythromycin enhanced phagocytosis by PMNs, but the three macrolides tested did not directly affect the functions of human PMNs against S. aureus.

Azithromycin↗