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E J Perea

Publications and source records attributed to E J Perea.

At least 37 records · Page 2Linked to original sources
PubMed1999

Uptake and intracellular activity of moxifloxacin in human neutrophils and tissue-cultured epithelial cells.

The penetration by moxifloxacin of human neutrophils (polymorphonuclear leukocytes [PMN]) and tissue-cultured epithelial cells (McCoy cells) was evaluated by a fluorometric assay. At extracellular concentrations of 5 mg/liter, the cellular-to-extracellular concentration ratios (C/E) of moxifloxacin in PMN and McCoy cells were 10.9 +/- 1.0 and 8.7 +/- 1.0, respectively (20 min; 37 degrees C). The uptake of moxifloxacin by PMN was rapid, reversible, nonsaturable (at extracellular concentrations ranging from 1 to 50 microg/ml), and not affected by cell viability. The uptake of moxifloxacin was affected by external pH and the environmental temperature. The incubation of PMN in the presence of sodium fluoride, sodium cyanide, and carbonyl cyanide m-chlorophenylhydrazone significantly decreased the C/E of this agent. Neither PMN stimulation nor phagocytosis of opsonized Staphylococcus aureus significantly affected the uptake of moxifloxacin by human PMN. This agent, at concentrations of 0.5, 1, and 5 mg/liter, induced a significant reduction in the survival of intracellular S. aureus in human PMN. In summary, moxifloxacin reaches much higher intracellular concentrations within phagocytic and nonphagocytic cells than extracellular ones, remaining active inside the neutrophils.

Anti-Infective Agents↗
PubMed1999

Resistance of Pseudomonas aeruginosa to imipenem induced by eluates from siliconized latex urinary catheters is related to outer membrane protein alterations.

The activity of imipenem against Pseudomonas aeruginosa HUS-3 decreased by 16 times in the presence of substances eluted from siliconized latex urinary catheters (SLUCs). SLUCs did not inactivate imipenem or increase beta-lactamase activity. The outer membrane of P. aeruginosa HUS-3 grown in the presence of eluate lacked an OprD-like protein and expressed a new 50-kDa protein. The decreased activity of imipenem against P. aeruginosa in the presence of SLUCs is related to the loss of an OprD-like protein and the expression of a new outer membrane protein.

Drug Resistance, Microbial↗
PubMed1998

The association of false-positive rapid plasma reagin results and HIV infection.

BACKGROUND AND OBJECTIVES: To study the relationship between a false positive rapid plasma reagin (RPR) result (FP), syphilis, and HIV infection in our patients. METHODS: A prospective study of the incidence of FP tests and syphilis in the general population and its relationship to HIV infection over a period of 6 months. RESULTS: 8.76% of the population were HIV positive. False positives were found in 15% and 1.2% of the HIV infected and noninfected patients, respectively; the attributable risk for HIV was 14.97. Syphilis was found in 5% and 0.9% of the positive and negative HIV patients, respectively; the attributable risk for HIV was 5.4. CONCLUSIONS: The incidence of false positive RPR results in the HIV-infected population is significantly higher than that of the non-HIV-infected patients.

False Positive Reactions↗
PubMed1998

In vitro activities of ketolide HMR 3647, macrolides, and clindamycin against Coryneform bacteria.

The in vitro activity of ketolide HMR 3647 against coryneform bacteria isolated from clinical samples was evaluated. Except against Corynebacterium jeikeium and C. urealyticum, HMR 3647 showed high activity against Corynebacterium spp., being more active than 14- and 16-membered macrolides, azithromycin, or clindamycin. HMR 3647 also had high in vitro activity against Brevibacterium spp. and Listeria monocytogenes.

Anti-Bacterial Agents↗
PubMed1998

Anaerobic bacteria in men with urethritis.

AIM: Investigation of the urethral flora in men with urethritis, with particular reference to anaerobic bacteria. METHODS: Multiple cultures were performed on three urethral samples from 110 men attending the STD Clinic of the School of Medicine in Seville: 35 with no evidence of urethritis (control group), and 75 with urethritis (17 gonococcal urethritis (GU) and 58 non-gonococcal urethritis (NGU)). In the 58 men with NGU, Chlamydia trachomatis was isolated in 16 (27.5%), Ureaplasma urealyticum in 18 (31%), Trichomonas vaginalis in two (3.4%) and no pathogens were isolated in the remaining 22 (38%) patients. RESULTS: Aerobic flora, mainly Staphylococcus spp., were isolated less frequently (41%) in patients with GU than in the control group (80%), and those with NGU (72%). Anaerobic flora were isolated in 62% of patients, with similar isolation rates in each group. Gram-negative anaerobes were more frequently isolated in men with urethritis, especially NGU, compared to controls (P < 0.05). Prevotella spp. and Bacteroides spp. were significantly more frequently isolated in patients with NGU, including Chlamydia-negative NGU. Fusobacterium spp. were more frequent in the Chlamydia-positive NGU than in the controls (P < 0.05). P. magnus was the most frequent anaerobic species found in the control group, while P. prevotii was most frequently seen in the urethritis group. B. ureolyticus, P. prevotii and P. tetradius were more frequent on the NGU group (P < 0.05). B. ureolyticus was commoner in patients with Chlamydia-negative NGU, while P. tetradius and P. asaccharolytica was commoner in those where C. trachomatis was isolated than in the control group. CONCLUSION: Urethral microflora isolated showed ten bacterial genus and 25 different species of anaerobes. The spectrum of these microflora changed with the presence of urethritis and varied with its aetiology.

Adult↗
PubMed1998

[Laboratory control in diagnosis and treatment of infective endocarditis].

Infectious endocarditis is caused by a wide variety of microorganisms. Etiological diagnosis depends either on direct methods, directed to the detection and isolation of the causative organisms, or serological methods. Blood cultures remain as the best method for the diagnosis of bacterial endocarditis. Blood culture technology has changed due to the appearance of new automatic continuous monitoring systems which shorten the detection time. Endocarditis with a negative blood culture has decreased below 5% because of new blood culture systems, new serological methods and molecular technology. The control of antimicrobial therapy in endocarditis must be performed by expert laboratories. A minimal bactericidal concentration, serum levels of antimicrobials and the serum bactericidal test are the most useful parameters. Their execution requires the use of strict protocols and interpretation must be carried out with an expert in clinical microbiology and infectious diseases.

Anti-Bacterial Agents↗
PubMed1998

[Opsonin requirements for phagocytosis of Enterococcus spp. by human polymorphonuclear leukocytes].

BACKGROUND: Interaction of Enterococcus spp. and host defense mechanisms is not well known. Opsonic requirements of Enterococcus faecalis and Enterococcus faecium to be phagocyted by human polymorphonuclear leukocytes (PMN) were evaluated. METHODS: Twenty strains (10 E. faecalis and 10 E. faecium) were studied. Phagocytosis was determined by a radiometric assay. Bacterial cells were labelled with 3H-adenine and opsonized with: a) 10% of human pool sera (HPS); b) 10% of decomplemented HPS, and c) albumin and fibronectin. RESULTS: Phagocytosis of Enterococcus spp. by PMN in the presence of HPS was significantly higher than that in the absence of opsonins. The phagocytosis of E. faecium was higher than that of E. faecalis. A strain-dependent effect of complement in the phagocytosis of Enterococcus spp. was observed. Neither albumin nor fibronectin showed an opsonic activity on Enterococcus spp. CONCLUSIONS: A great heterogeneity in the opsonic requirements of Enterococcus spp. was observed. Serum opsonins show a critical role in the phagocytosis of E. faecalis and E. faecium by PMN, this effect being more relevant with E. faecium. A strain-dependent opsonic activity of complement was observed.

Adult↗
PubMed1997

Uptake and intracellular activity of trovafloxacin in human phagocytes and tissue-cultured epithelial cells.

The penetration of trovafloxacin into human polymorphonuclear leukocytes (PMNs), human peritoneal macrophages, and tissue-cultured epithelial cells (McCoy cells) was evaluated. The cellular concentration to extracellular concentration (C/E) ratios of trovafloxacin were greater than 9 for extracellular concentrations ranging from 0.5 to 25 micrograms/ml. The uptake of trovafloxacin by PMNs was rapid, reversible, nonsaturable, not energy dependent, and significantly increased at 4 degrees C. Ingestion of opsonized zymosan, but not opsonized Staphylococcus aureus, significantly increased the amount of PMN-associated trovafloxacin. This agent at concentrations of 0.5 and 1 microgram/ml induced a greater reduction in the survival of intracellular S. aureus in PMNs than ciprofloxacin and ofloxacin. It was concluded that trovafloxacin reaches concentrations within phagocytic and nonphagocytic cells several times higher than the extracellular ones, while it remains active in PMNs.

Anti-Infective Agents↗
PubMed1997

[Penetration of azithromycin into human neutrophils: effect of hydrogen peroxide production].

BACKGROUND: The aim of this study was to evaluate the uptake of azythromycin at therapeutic concentrations by human polymorphonuclear leukocytes (PMN), as well as the effect of environmental temperature, pH, and cell viability on this uptake. The effect of azythromycin and other macrolides on hydrogen peroxide production by PMN was also assessed. METHODS: Uptake of radiolabeled azythromycin by PMN was determined by a radiometric technique. Hydrogen peroxide production by PMN was measured by the phenol red method. RESULTS: The intracellular concentrations achieved by azythromycin in PMN were 20 to 60 fold the extracellular ones, even at extracellular concentration of 0.125 mg/l. The uptake was significantly affected by low temperature, acid pH, and cell viability. Hydrogen peroxide production was not affected by the macrolides studied. CONCLUSIONS: Azythromycin at therapeutical concentrations achieves high intracellular accumulation in human PMN. The effect of environmental temperature, pH and cell viability on uptake points out that a passive diffusion, with lysosome trapping, is the essential mechanism of azythromycin uptake by phagocytic cells. In spite of the high intracellular concentrations achieved by macrolides, hydrogen peroxide production by PMN is not affected by these compounds.

Anti-Bacterial Agents↗
PubMed1997

[Usefulness of the disk diffusion method for evaluating the sensitivity of Neisseria meningitidis to penicillin and cefotaxime].

BACKGROUND: Routine susceptibility testing of Neisseria meningitidis to penicillin and other beta lactams is recommended after the isolation of N. meningitidis of moderately resistant to penicillin (MRP). We have evaluated the disk-diffusion method to determine susceptibility of N. meningitidis to penicillin (using disks of either penicillin or oxacillin) and to cefotaxime. METHODS: Fifty-four strains of N. meningitidis isolated from clinical samples were studied. MICs of penicillin and cefotaxime were determined by microdilution. Disks of 2 U of penicillin, 1 microgram of oxacillin and 30 micrograms of cefotaxime and two culture media, Mueller-Hinton agar (MHA) and MHA supplemented with 5% sheep blood (MHS) were used in the disk-diffusion assay. RESULTS: For disk of 2 U of penicillin assayed in MHA, 86.4% of the susceptible strains and 20% of MRP strains were considered susceptible when a breakpoint of 28 mm was considered. None of the MRP strains was considered susceptible when using MHS, but only 38.6% of susceptible strains appeared as such on this medium. When a 1 microgram oxacillin disk was used all MRP strains presented an inhibition zone < or = 10 mm on both MHA and MHS, but 54.4 and 4.5% of susceptible strains presented an inhibition zone > or = 11 mm on MHA and MHS, respectively. All strains were susceptible to cefotaxime, showing inhibition zones around a 30 micrograms disk on MHA and MHS of > or = 35 mm and > or = 25 mm, respectively. CONCLUSION: Disk diffusion with cefotaxime (30 micrograms) allows to determine susceptibility of N. meningitidis to this antimicrobial agent. Discs of penicillin (2 U) and oxacillin (1 microgram) are not useful for screening of MRP N. meningitidis.

Cefotaxime↗