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M Hermida

Publications and source records attributed to M Hermida.

34 records · Page 2Linked to original sources
PubMed1989

[Resistance caused by hyperproduction of chromosomal beta-lactamase in Pseudomonas aeruginosa].

From 120 Pseudomonas aeruginosa strains selected for their slight susceptibility to ceftazidime (MIC greater than or equal to 16 micrograms/ml) we studied the characteristics of beta-lactamases and their susceptibility to aminoglycoside and to beta-lactam antibiotics. The quantitative spectrum, chromosomic beta-lactamase hyperproduction and the isoelectric point of beta-lactamases were also studied as well as the MIC in solid medium, inoculum 5 x 10(4) cfu. About 14.7% of strains moderately susceptible to ceftazidime and 88.4% of those resistant, were hyperproducers of chromosomic beta-lactamases. All the strains were resistant to ureidopenicillins, cefotaxime and moxalactam, 55.8% to monobactams and 35% were also resistant to cefsulodine; all of them were susceptible to imipenem. In bacteria isolated from twelve patients a loss of susceptibility could be observed against ceftazidime and other beta-lactams. There was also an increase in chromosomic beta-lactamase production during the treatment with antibiotics.

Aminoglycosides↗
PubMed1989

[Type TEM beta-lactamase activity in a Neisseria meningitidis strain].

We studied the beta-lactamase activity characteristics of a penicillin G resistant N. meningitidis strain (MIC = 8 micrograms/ml) isolated from a septicemic process, in an eleven month old girl, attended in the Sabadell Hospital (Barcelona). The beta-lactamase substrate profile was broad-spectrum (it hydrolyses penicillin G and cephaloridine) and the nitrocefin hydrolysis was inhibited by clavulanic acid. The analytical isoelectric focusing of the enzyme showed that the isoelectric point of the main band and, the secondary bands, were compatible with those of the type TEM-1 standard enzyme. We also obtained a positive DNA-DNA hybridization with the TEM-1 beta-lactamase (pBR322 plasmid).

Humans↗
PubMed1986

Incidence of strains producing plasmid determined beta-lactamases among carbenicillin resistant Pseudomonas aeruginosa.

A total of 1056 strains of Pseudomonas aeruginosa isolated from human clinical specimens from patients was collected from eight laboratories in order to study the frequency of plasmid-determined beta-lactamase producers and the different enzymes represented. The strains from each laboratory comprised consecutive, non-repeated, clinical isolates. In the 166 strains selected because they were carbenicillin resistant, the isoelectric points of the beta-lactamases were studied by means of analytical isoelectric focusing and the different types of plasmid-determined beta-lactamases identified. Seventy-five of the strains (45.18%) were plasmid-mediated beta-lactamase producers; the frequency varied among laboratories from 0% to 100%. Overall the most frequently identified beta-lactamase type was PSE-1 (49.34%) followed by TEM-1 (37.34%). The remaining carbenicillin-resistant strains did not produce plasmid-determined beta-lactamases.

Carbenicillin↗
PubMedDate not supplied

Semi-automated direct epifluorescent filter technique for total bacterial count in raw milk.

The Direct Epifluorescent Filter Technique (DEFT) and the reference method of counting total bacterial colonies on Petri dishes were compared. IDF Standards 128 (1985) and 161A (1995) were applied. A total of 496 samples of milk were analyzed. Colony forming units per microL milk were transformed to decimal logarithmic units: log (cfu/microL). The repeatability standard deviation, Sr = 0.114, was typical for a routine microbiological method. To study the carryover at different levels of bacteria, 3 tests were performed on milk samples of approximately 100, 700, and >1000 cfu/microL. For the first 2 experiments, no carryover was detected; in the milk sample with >1000 cfu/microL, the carryover was <0.12%. When the DEFT counts were regressed versus the reference method, the values of the slope and intercept were 0.92 and 0.17, respectively; the correlation coefficient was r = 0.84; and the residual standard deviation was Syx = 0.287. The paired t-test showed that the reference method and DEFT do not give significantly different results (p = 0.05).

Animals↗
PubMedDate not supplied

[Resistance of Haemophilus influenzae and Haemophilus parainfluenzae to beta-lactam antibiotics. Characterization of the beta-lactamases].

We have studied the susceptibility to ampicillin and the characteristics of the beta-lactamase activity of the 169 Haemophilus spp. strains (128 H. influenzae, 40 H. parainfluenzae and one H. paraphrophilus) isolated during 12 months, years 1988-1989, in the Hospital del Mar clinical microbiology laboratory. Our objective was to know in the strains of our center the frequency of those resistant or slightly susceptible to ampicillin, the role of beta-lactamases in the loss of susceptibility and the type of enzymes involved. Susceptibility was studied by diffusion for all the antibiotics tested and also confirmed by dilution for ampicillin and other beta-lactam antibiotics. Beta-lactamase production was identified by nitrocefin hydrolysis. The isoelectric point of the beta-lactamase and the identification of their types were determined by analytic isoelectric focusing. The presence of the codifying gene of the TEM-1 enzyme was studied by hybridization with a TEM-1 probe. Of the H. influenzae strains 35 were ampicillin resistant, one moderately susceptible and of the H. parainfluenzae strains six were resistant and two moderately susceptible; all were susceptible to the combination of amoxicillin/clavulanic acid. The ampicillin-resistant strains were beta-lactamase producers. In 40 strains, by isoelectric focusing, the type TEM-1 was identified and the hybridization was positive; in one H. parainfluenzae strain a beta-lactamase of pl 5.8 was observed and the hybridization with TEM-1 probe was negative. The three strains moderately susceptible to ampicillin did not produce beta-lactamase.

Adult↗
PubMedDate not supplied

[Secondary aorto-duodenal fistula and aneurysm of the abdominal aorta].

A case report of a man 58 years old with a history of surgical treatment for an aortic-abdominal aneurysm by an aortobifemoral bifurcated vascular graft is presented. The patient was admitted on Urgencies with digestive hemorrhage and he was submitted to an emergent surgical procedure. Surgical findings were a secondary aortoduodenal fistula and an aortic abdominal aneurysm located between renal arteries and the bifurcated prosthesis. Duodenal fistula was then closed and aortic aneurysm removed, interposing an straight Dacron prosthesis. Fifteen days after procedure, patient was discharged and a suitable duodenal and aortic restauration was demonstrated by duodenal transit and angiography. Two months latter, patient is asymptomatic. Relevant details in regard to diagnosis and treatment of such relatively rare affection are commented.

Aorta, Abdominal↗
PubMedDate not supplied

Determination of fat, protein, and total solids in cheese by near-infrared reflectance spectroscopy.

Near-infrared reflectance (NIR) spectroscopy was used to analyze fat, protein, and total solids in cheese without any sample treatment. A set of 92 samples of cow's milk cheese was used for instrument calibration by principal components analysis and modified partial least-square regression. The following statistical values were obtained: standard error of calibration (SEC) = 0.388 and squared correlation coefficient (R2) = 0.99 for fat, SEC = 0.397 and R2 = 0.98 for protein, and SEC = 0.412 and R2 = 0.99 for total solids. To validate the calibration, an independent set of 25 cheese samples of the same type was used. Standard errors of validation were 0.47, 0.50, and 0.61 for fat, protein, and total solids, respectively, and R2 for the regression of measurements by reference methods versus measurements by NIR spectroscopy was 0.98 for the 3 components.

Calibration↗
PubMedDate not supplied

Analysis of fermented milk products by near-infrared reflectance spectroscopy.

Fat, protein, and total solids in fermented milk were determined by near-infrared reflectance spectroscopy (NIRS). A set of 107 samples from diverse types of fermented milk (whole, skimmed, with added flavors, and without added flavors) were used to calibrate the instrument by modified partial least-square regression. Global calibration, using all samples, was more effective than specific calibrations using fewer samples of each type. Standard errors of a calibration were 0.071 for fat, 0.075 for protein, and 0.083 for total solids. Values of the correlation coefficient square (R2) were 0.997 for fat, 0.981 for protein, and 1.000 for total solids. Calibration was validated with an independent set of 34 samples of the same types. Standard errors of validation were 0.08, 0.14, and 0.25 for fat, protein, and total solids, respectively, and values of R2 for the regression of measurements by NIRS versus reference methods were 1.00 for fat and total solids and 0.94 for protein. When Standard 128 of the International Dairy Federation was used to compare NIRS results with those from reference methods, no significant differences were found (p = 0.05).

Calibration↗