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Biomedical subjects

F Bert

Publications and source records attributed to F Bert.

At least 19 recordsLinked to original sources
PubMed2000

Population study of Aymara Amerindians for the PCR-DNA polymorphisms HUMTH01, HUMVWA31A, D3S1358, D8S1179, D18S51, D19S253, YNZ22 and HLA-DQalpha.

Allele and genotype frequencies for eight DNA polymorphisms (HUMTH01, HUMVWA31A, D3S1358, D8S1179, D18S51, D19S253, YNZ22 and HLA-DQalpha) were determined in a population sample of Aymara Indians from Bolivia using PCR. No deviations of the observed allelic frequencies from Hardy-Weinberg equilibrium were found for all the systems studied. Significant differences in the allele frequencies were found between the Aymara and Quechua populations only for HUMVWA31A, which suggests a certain degree of genetic differentiation between the two populations.

Alleles↗
PubMed1999

[Current microbiological problems. Antibiotic resistance and therapeutic problems raised by Pseudomonas aeruginosa].

RESISTANCE: Pseudomonas aeruginosa is characterized by its low intrinsic susceptibility to many antibiotics and its capacity to acquire additional resistance mechanisms to usually active drugs. Some beta-lactam resistance mechanisms are well known (penicillinase production, cephalosporinase overproduction) and others have been recently identified, such as active efflux systems, which confer coresistance to quinolones, and new beta-lactamases which are limited to a few countries (extended-spectrum beta-lactamases, imipenemase). Ceftazidime remains the most active beta-lactam agent. ACTIVE DRUGS: Among aminoglycosides, amikacin and isepamicin are the most frequently active drugs. The use of fluoroquinolones is limited by a high incidence of acquired resistance. The percentage of resistant strains is highly variable according to countries, hospitals and wards. CLINICAL PRACTICE: Therapy, usually based on a beta-lactam-aminoglycoside combination, will be empirical at first, according to local epidemiological factors, site of infection and previously administered antibiotics, then re-evaluated according to susceptibility results.

Cross Infection↗
PubMed1998

Multi-resistant Pseudomonas aeruginosa outbreak associated with contaminated tap water in a neurosurgery intensive care unit.

From July 1995 to November 1996, multi-resistant Pseudomonas aeruginosa O11 was isolated from 36 patients admitted to a neurosurgery intensive care unit. The strain was resistant to ticarcillin, ceftazidime, imipenem, gentamicin and ciprofloxacin, and susceptible to amikacin. Nine patients were colonized only; the remaining 27 patients had at least one infected site (17 urinary infections, 10 pneumonias and four with sinusitis). P. aeruginosa O11 with the same resistance pattern was isolated from tap water. The strain was also cultured from enteral nutrition solutions given to two infected patients. DNA macrorestriction analysis with XbaI established the similarity of the isolates from patients, tap water and solutions. The outbreak was controlled after reinforcement of isolation procedures for infected patients, changing the mode of enteral nutrition and replacement of all sinks in the unit. The sinks were presumably the main source of P. aeruginosa during this outbreak, via the hands of the nursing staff or nutrition solutions contaminated with tap water.

Adolescent↗
PubMed1998

Clinical significance of bacteremia involving the "Streptococcus milleri" group: 51 cases and review.

Fifty-one cases of bacteremia due to the "Streptococcus milleri" group were analyzed. Among these were 40 patients with underlying diseases, and associated local infections were present in 27 patients. The most frequent sites of infection were the thoracic cavity and the digestive and hepatobiliary tracts. A probable portal of entry related to mucosal-barrier trauma was identified for an additional 16 patients. The origin of bacteremia was unknown for the remaining eight patients. Abscess formation was evident for only six patients, and there were no cases of endocarditis. Multiple positive blood cultures and polymicrobial bacteremia were associated significantly with the presence of local sites of infection. The most common causative species were Streptococcus anginosus and Streptococcus constellatus. Two patients died of bacteremia.

Abscess↗
PubMed1998

Quechua Amerindian population characterized by HLA-DQ alpha, YNZ22, 3'APO B, HUMTH01, and HUMVWA31A polymorphisms.

Allele and genotype frequencies of DNA polymorphisms were determined in a population sample of Quechua (n = 113) using the polymerase chain reaction (PCR). We report data on the frequencies of HLA-DQ alpha, YNZ22, 3'ApoB, HUMTH01 and HUMVWA31A alleles and the distribution of the different genotypes. No significant deviations between observed and expected numbers were found, thus assuming the Hardy-Weinberg equilibrium.

Bolivia↗
PubMed1998

[Bacteria isolated from protected bronchopulmonary samples: variation as a function of the previous length of stay in the recovery room].

We retrospectively reviewed the variation of the organisms recovered from 403 protected bronchopulmonary specimens in three surgical intensive care units according to the time elapsed from admission. The predominant pathogens during the four first days were Haemophilus influenzae (33.3%), Staphylococcus aureus (18.2%), mostly methicillin susceptible strains, and Streptococcus pneumoniae (14.3%). After the fourth day, they were progressively replaced by typical nosocomial bacteria such as methicillin resistant Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii. For Pseudomonas aeruginosa and cephalosporinase-producing Enterobacteriaceae, strains resistant to third generation cephalosporins occurred significantly later than the susceptible strains. These results indicate that the time elapsed from intensive care unit admission has a major influence on the bacteriology of respiratory tract infections, but no clear cut-off point between early-onset and late onset pneumonia is evident.

Bacteria↗
PubMed1997

Differentiation of human and animal strains of Streptococcus dysgalactiae by pulsed-field gel electrophoresis.

The genetic diversity among 54 human isolates and 33 animal isolates belonging to the species Streptococcus dysgalactiae (20 alpha-haemolytic Streptococcus dysgalactiae, 23 Streptococcus equisimilis, 43 group G streptococci and one group L streptococcus) was evaluated by macrorestriction analysis of chromosomal DNA with SmaI and resolution by pulsed-field gel electrophoresis. This technique revealed a high degree of intraspecies polymorphism, leading to the differentiation of 80 distinct banding patterns, and identified the presence of two major clusters, one containing isolates of human origin and the other isolates of animal origin. These results suggest than human and animal isolates of S.dysgalactiae are genetically distinct, and support the recent proposal of the subspecies S. dysgalactiae subsp. equisimilis for human isolates. The heterogeneity revealed within isolates from the same host type indicates that pulsed-field gel electrophoresis is a powerful epidemiological tool for studying S. dysgalactiae infections.

Animals↗
PubMed1997

Pulsed-field gel electrophoresis is more discriminating than multilocus enzyme electrophoresis and random amplified polymorphic DNA analysis for typing pyogenic streptococci.

The SmaI restriction endonuclease digestion patterns of chromosomal DNAs from 99 pyogenic streptococci belonging to Lancefield group A (41 Streptococcus pyogenes), group C (seven S.dysgalactiae, 11 "S. equisimilis", three S. equi, eight S. zooepidemicus) and group G (25 human group G Streptococcus, four S. canis) were analyzed by pulsed-field gel electrophoresis (PFGE), and the results were compared with those previously obtained by multilocus enzyme electrophoresis (MLEE) and random amplified polymorphic DNA analysis (RAPD). PFGE revealed 93 distinct types among the 99 strains, and no patterns were common to strains of different species. The discriminatory power of PFGE was greater than that of MLEE and RAPD for groups A and G streptococci. The polymorphism among group C streptococci was similar with the three techniques. PFGE is, therefore, the most efficacious method for epidemiological typing of pyogenic streptococci.

DNA, Bacterial↗
PubMed1997

Galactans and cellulose in flax fibres: putative contributions to the tensile strength.

The proton spin-spin relaxation time, T2, measured from solid-state NMR, indicates a greater rigidity for cellulose than for the adhesive matrix between the microfibrils of flax ultimate fibres. Cytochemical and biochemical analyses allow the identification of: (1) EDTA-soluble RG I-polymers in the primary walls and cell junctions of fibres; (2) long 1 --> 4-beta-D-galactan chains between primary and secondary wall layers; and (3) arabinogalactan-proteins throughout the secondary walls. These polymers in the adhesive matrix between microfibrils and/or cellulose layers ensure that cracks propagate along the matrix rather than across the fibres and play an important role in allowing flax fibres to approach the tensile strength of advanced synthetic fibres like carbon and Kevlar.

Biopolymers↗
PubMed1997

Septicemia caused by Streptococcus canis in a human.

We describe a case of septicemia due to Streptococcus canis in a 77-year-old man. The organism was presumably transmitted from a domestic animal. Ulcers of the lower limbs were the likely portals of entry. The differentiation between Streptococcus canis and Streptococcus dysgalactiae was based on biochemical properties and DNA macrorestriction analysis by pulsed-field gel electrophoresis.

Aged↗
PubMed1996

Sinusitis in mechanically ventilated patients and its role in the pathogenesis of nosocomial pneumonia.

Nosocomial sinusitis is a complication of endotracheal intubation and mechanical ventilation in critically ill patients. Its incidence is often underestimated because of a lack of clinical signs. It is suspected in patients with nasal discharge or unexplained fever. Its diagnosis is based on radiological examination, by radiograph or computed tomography scan, and microbiological cultures of maxillary sinus aspirate. Maxillary sinusitis is often associated with involvement of the sphenoid, ethmoid, and/or frontal sinuses. Its incidence varies greatly according to diagnostic criteria and the population studied. Infectious sinusitis is less frequent than noninfectious sinusitis, occurring in 20 to 30% of patients intubated for at least seven days. Its incidence is higher in nasotracheally than in orotracheally intubated patients. Other risk factors include nasogastric tubes and head trauma. The main causative agents are gram-negative bacilli, primarily Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae, but Staphylococcus aureus and yeasts are also common. Patients with nosocomial sinusitis are more likely to develop pneumonia than those without sinusitis. The sinus provides a bacterial reservoir from which organisms may seed the tracheobronchial tree. The association of sinusitis and pneumonia is mainly due to Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. The treatment of sinusitis is based on the removal of all nasal tubes, topical decongestants, and maxillary sinus drainage and lavage. The role of intravenous antibiotics is controversial.

Anti-Bacterial Agents↗
PubMed1996

Comparative distribution of resistance patterns and serotypes in Pseudomonas aeruginosa isolates from intensive care units and other wards.

The resistance patterns and O-serotypes of 2952 Pseudomonas aeruginosa isolates were studied and the relationship between patterns and serotypes was investigated. The penicillinase-producing and cephalosporinase-overproducing phenotypes were significantly more frequent in intensive care units than other wards, but there was no difference for the intrinsic resistance phenotype. The predominant serotypes were O6, O11 and O1. The incidence of serotype O12 was low. O11 isolates were more common in intensive care units and more resistant to all antibiotics than other isolates. Most O12 isolates had a penicillinase-producing phenotype and were resistant to aminoglycosides and ciprofloxacin, but susceptible to fosfomycin.

Aminoglycosides↗
PubMed1996

Analysis of genetic relationships among strains of groups A, C and G streptococci by random amplified polymorphic DNA analysis.

Random amplified polymorphic DNA (RAPD) analysis was evaluated for its capacity to distinguish species and strains within species of groups A, C and G streptococci. The 99 strains tested, previously typed by multilocus enzyme electrophoresis (MLEE), included 41 group A streptococci (Streptococcus pyogenes), 25 group G Streptococcus spp. (GGS), seven S. dysgalactiae, 11 S. equisimilis, four S. canis, three S. equi and eight S. zooepidemicus. The combined data obtained with three single primers distinguished 82 types. RAPD analysis provided taxonomic results that were in general agreement with previous species classification based on DNA-DNA homology and MLEE. The intraspecies typing efficiency of the technique was significantly improved by the parallel use of several primers. RAPD analysis had greater discriminatory power than MLEE for GAS and GGS. There was not total agreement between the two techniques as RAPD distinguished strains with identical electrophoretic types, whereas MLEE differentiated strains with identical PCR types. RAPD analysis did not distinguish all GAS strains with different biotypes and its already high discriminatory power was further enhanced by concomitant biotyping.

Animals↗
PubMed1996

[Transmission of infection in oral medicine. Evaluation of the risk of transmission in the office surgery].

The present study was designed to estimate the risk of transmission of infectious diseases by dental equipment in stomatology. The protocol was carried out on 30 patients. The three following samples were collected from each patient: (a) oral flora before any treatment, (b) aerosol produced by the hand-piece before internal decontamination, (c) aerosol produced by the hand-piece after internal decontamination. The results of this study indicate there was a risk of transmission of infectious diseases in 3 cases (10%) with dental equipment, even if there were no consequences for healthy individuals. We have to improve the security in stomatology, with internal and external decontamination after each patient.

Adult↗
PubMed1996

[Comparison of the activity of beta-lactams against Pseudomonas aeruginosa according to phenotypes of resistance].

The in vitro activity of ticarcillin, ticarcillin-clavulanic acid, piperacillin, piperacillin-tazobactam, cefsulodin, ceftazidime, cefepime, cefpirome and aztreonam was evaluated against 130 isolates of Pseudomonas aeruginosa with various beta-lactam phenotypes. MICs were determined by the agar dilution method and inhibition method and inhibition zones by the disk test. The resistance mechanisms were characterized by the iodometric method. The activity of cefepime was greater than that of cefpirome whatever the resistance phenotype. Some ticarcillin-susceptible strains were intermediate to cefepime and cefpirome. Most strains with a penicillinase or "intrinsic resistance" phenotype were susceptible to ceftazidime but intermediate to cefepime and cefpirome. Only 10% of cephalosporinase-over-producing strains remained susceptible to cefepime.

Anti-Bacterial Agents↗