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Biomedical subjects

A Audurier

Publications and source records attributed to A Audurier.

At least 19 recordsLinked to original sources

[Brucella vaccination in professionally exposed subjects. Prospective study].

This prospective phase IV study on cohort concerns a vaccine made of the phenol-insoluble fraction of Brucella abortus biotype 1 (B19 strain). Three hundred and three professionally exposed subjects entered the study; 161 out of 182 subjects (88.5 percent) with negative response to an intradermal test for detection of previous contamination accepted to be vaccinated. Booster injections were given 18 and 36 months after vaccination. Local pain was observed after 45.2 percent of injections and moderate systemic reactions after 5 percent of injections. Seropositivity after primary vaccination reached 80 percent. The booster injection, justified by a major decrease of this rate after 18 months, gave exactly the same response of the thymo-independent type. This vaccinal schedule did not result in detectable hypersensitivity. The clinical effectiveness of the vaccine could not be evaluated accurately because of the insufficient number of subjects. The possibility of subclinical infection in vaccinated subjects calls for wider comparative studies of vaccinated versus non-vaccinated subjects.

Brucella Vaccine

A comparative study of randomly amplified polymorphic DNA analysis and conventional phage typing for epidemiological studies of Listeria monocytogenes isolates.

The analysis of RAPD profiles generated by PCR with a single 10-mer, HLWL74, was compared to bacteriophage susceptibility data for epidemiological typing of Listeria monocytogenes strains. A total of 104 L. monocytogenes strains was screened, all from serogroup 1 or serotype 4b. Of these, 53 had been isolated during 6 different listeriosis outbreaks. The remaining 51 strains were chosen randomly from our collection. A total of 38 RAPD types were observed, although each epidemic group of strains isolated during one of these outbreaks displayed a specific RAPD profile. For 98% of the strains isolated during outbreaks, the correlation between RAPD typing and phage typing was complete. Only one strain, typed as epidemic by phage typing, was clearly distinguishable from the others by RAPD analysis. Among the 51 strains not related to an outbreak, 12 were linked to epidemic groups by RAPD analysis. Two of these rearrangements were supported by phage typing. The remaining 10 strains could be excluded by phage typing from any of the epidemic groups studies. Considering all 104 isolates, the decision to relate a strain to a particular epidemic group or to exclude a strain from any epidemic group was the same for 92 isolates, using either phage typing or RAPD analysis. The RAPD analysis, which is quick, simple and suited for automation, is proposed as an attractive alternative for phage typing in epidemiological studies of listeriosis.

Bacterial Typing Techniques

Plasmids in Listeria monocytogenes in relation to cadmium resistance.

One hundred and seventy-three unrelated Listeria monocytogenes strains isolated from humans, animals, the environment, and food were analyzed for the presence of plasmids. Extrachromosomal DNA was found in 28% of the strains. Plasmid DNA was extracted more frequently from L. monocytogenes serogroup 1 strains (35%) than from serogroup 4 strains (15%). Among strains from food and the environment, 40% and 29%, respectively, harbored plasmids, whereas only 13% of the strains from humans and animals with listeriosis bore plasmids. We also investigated the susceptibility of 90 strains to seven antibiotics and four heavy-metal salts. No antibiotic resistance could be detected, but 95.3% of the plasmid-positive strains and only 12.7% of the plasmid-negative strains were resistant to cadmium. The plasmid-determined genetic basis of cadmium resistance was proven by conjugation between strains of L. monocytogenes and by cure of the plasmid. This is the first time that plasmids of L. monocytogenes have been shown to be associated with cadmium resistance.

Animals

[Post-antibiotic diarrheas: role of Klebsiella oxytoca].

From May 1989 to January 1991, 20 patients were investigated for antibiotic-associated acute diarrhea. Colonoscopy or rectosigmoidoscopy was performed in each patient. Cultures of colonic mucosal biopsies were carried out using conventional culture grounds (cystine-lactose-electrolyte-deficient). The aim of this study was to investigate the role of a gram negative bacillus: Klebsiella oxytoca. Among the 20 patients with antibiotic-associated acute diarrhea, 11 had bloody and mucus diarrhea and colitis ranging from a right-sided hemorrhagic to diffuse acute ulcerative or erosive colitis, 7 had a grossly normal colonic appearance, while 2 had mucus diarrhea and pseudomembranous colitis. Of colonic biopsies cultures obtained from 36 control patients, 15 had a normal colonic appearance, 15 had ulcerative or crohn's colitis, 6 had well-tolerated amoxicillin therapy. Klebsiella oxytoca was never found in the 36 control patients; Klebsiella oxytoca was noted among 8/11 patients with mucus-discharging and bloody diarrhea. These results suggest that antibiotic-associated, non pseudomembranous colitis is frequently associated with Klebsiella oxytoca infection, which may be the cause of this type of colitis.

Adult

Treatment failure and recurrent human listeriosis.

We review 12 patients and report an additional two new patients, each of whom had two episodes of listeriosis. In seven patients the two episodes were due to the same strain of Listeria monocytogenes, and we speculate that this was a reactivation of the original infection. In one patient, isolates of L. monocytogenes from the two episodes differed, suggesting a chance reinfection. Twelve of the patients in this series received inappropriate therapy. Ampicillin plus an aminoglycoside for three to four weeks remain the treatment of choice.

Adult

Pathogenicity of Listeria monocytogenes isolates in immunocompromised mice in relation to listeriolysin production.

The virulence of 74 Listeria monocytogenes isolates from clinical cases and food products and of 11 isolates of other Listeria species was tested in mice immunocompromised with carrageenan. Isolates of species other than L. monocytogenes were not lethal to such mice. All 29 clinical isolates of L. monocytogenes (serotypes 1/2a, 1/2b, 4b) and 33 of 42 isolates of various serotypes isolated mainly from dairy products killed all test mice (100% lethality) at an inoculum of 10(4) cfu/mouse. All lethal strains of L. monocytogenes were haemolytic and possessed the 58-Kda band specific for listeriolysin O as demonstrated by SDS-PAGE immunoblotting. The nine avirulent strains of L. monocytogenes had detectable haemolytic activity, but in six of them this activity was significantly weaker than in virulent strains and the 58-Kda band was not detected. The other three avirulent strains were highly haemolytic and possessed the 58-Kda band, which suggests that other factor(s) could be involved in the virulence of L. monocytogenes.

Animals

DNA polymorphism in strains of Listeria monocytogenes.

DNA polymorphism in 35 Listeria monocytogenes strains belonging to serovars 1/2a, 1/2b, 1/2c, and 4b was studied by genomic DNA digestion. The restriction endonucleases ApaI and NotI, which cleave DNA at rare sequences, were used, and DNA fragments were analyzed by pulsed-field gel electrophoresis. Restriction fragment length polymorphism varied among different serovars and was used for epidemiological studies, but serovar 1/2c isolates could not be analyzed because their restriction patterns were indistinguishable. The genome sizes were calculated by addition of the sizes of the ApaI fragments and were found to be about 2,660 kb for serovar 1/2a strains, 2,640 kb for serovar 1/2b strains, and 2,710 kb for serovar 4b strains but only 2,340 kb for serovar 1/2c strains. This last group therefore appears to differ from the other serovar strains by the absence of restriction fragment length polymorphism and a chromosome that is 15% shorter, suggesting that strains of serovar 1/2c have quite recently emerged.

Bacterial Typing Techniques

Epidemiological markers for epidemic strain and carrier isolates in an outbreak of nosocomial oxacillin-resistant Staphylococcus aureus.

An outbreak of nosocomial infections occurring in a postoperative intensive care unit was caused by a single strain of oxacillin-resistant Staphylococcus aureus. Six patients were infected, or colonized, by this strain, which was traced by using the following four epidemiological markers: antibiogram, bacteriophage type, capsular polysaccharide type, and esterase electrophoretic type. This strain was compared with S. aureus isolates obtained from the noses of 13 carriers from a group of 42 staff members. A good correlation in terms of phenotypic markers was found between the epidemic strain and a strain isolated from one carrier. Both exhibited the same pattern of multiple resistance as well as the same phage type, 77, capsular polysaccharide type, 5, and esterase electrophoretic type, 6. In contrast, an oxacillin-resistant strain, isolated from another carrier, differed from the epidemic strain by susceptibility to rifampin and by susceptibility to four additional bacteriophages. The other 11 strains isolated from carriers were susceptible to oxacillin and exhibited widely different phenotypes. These results confirm the interest of using several epidemiological markers to trace the spread of epidemic S. aureus strains and to delineate the carrier strains.

Bacterial Typing Techniques

Direct testing of blood culture for detection of the serotype 5 and 8 capsular polysaccharides of Staphylococcus aureus.

Monoclonal antibodies (MAbs) reactive with serotype 5 and 8 capsular polysaccharides of Staphylococcus aureus have been used to test, by enzyme-linked immunosorbent assay (ELISA), blood culture fluids for the presence of S. aureus. A total of 748 blood cultures from 665 patients yielding 706 bacterial isolates belonging to more than 26 bacterial species were studied. All blood cultures containing bacterial strains belonging to species other than S. aureus were negative in ELISA. All 23 blood cultures containing serotype 5 S. aureus were positive in ELISA with the corresponding MAb. Out of 20 blood cultures containing serotype 8 S. aureus, 19 were positive with the corresponding MAb. All 5 blood cultures containing nontypeable S. aureus were negative in ELISA with both MAbs. This method provides reliable identification of serotype 5 or serotype 8 S. aureus by direct testing of blood culture fluids with ELISA.

Animals

Thermal resistance of Listeria monocytogenes.

Two methods were used to study the thermal resistance of Listeria monocytogenes. The D60 degrees C values ranged from 1.3-6.5 min in an open vessel. D72 degrees C varied from 0.06-1.5 s and z from 3.1-6.5 K (38 strains) in capillary tubes. Therefore a conventional pasteurization process of 15 s at 72 degrees C could assure 10-750 decimal reductions, depending on the strain. Six days enrichment, at 4 degrees C in milk prior to incubation at 37 degrees C, did not show any influence on measured heat resistance (4 strains). A significant difference in thermal resistance among strains according to their serotype was noted: strains belonging to serogroup 1 were more heat resistant than those belonging to serogroup 4.

Animals

Heat resistance of Listeria monocytogenes.

Two methods were used to study the thermal resistance of Listeria monocytogenes. The D60 degrees C values ranged from 1.3 to 6.5 s in a open vessel. D72 degrees C varied from 0.06 to 1.5 s and z from 3.1 to 6.5 K (38 strains) in capillary tubes. Therefore a conventional pasteurization process of 15 s at 72 degrees C could assure 10 to 250 decimal reductions, depending on the strain. Six days enrichment at 4 degrees C in milk prior to incubation at 37 degrees C did not show any influence on measured heat resistance (4 strains). A significant difference of thermal resistance among strains according to their serotype was noted: strains belonging to serogroup 1 were more heat resistant than those belonging to serogroup 4.

Hot Temperature

[Evaluation of a screening test for urinary infection].

The interest of using a reagent strip (Multistix-8 SG, Ames, Miles Laboratories) as a screen for urinary tract infection was evaluated in a clinical study involving several sites and 2,183 adult urine specimens of which 340 were infected. The results are expressed in terms of sensitivity, specificity, predictive value of a negative and positive test. The predictive value of a negative test for nitrites in combination with leucocytes (97.5%) justifies the use of the reagent strip in eliminating non-infected urine.

Bacteriological Techniques

Erythromycin ethyl succinate: diffusion through interstitial dermal fluid.

Erythromycin is widely used in dermatology. There are few studies of its diffusion in the skin. The diffusion of erythromycin ethyl succinate (EES) in dermal fluid has now been investigated by the suction blister method. Suction blister fluid (SBF) and blood samples were collected from 10 volunteers before administration of 1 g EES and 10 times during the following 24 h. The median peak serum level was 2.05 micrograms/ml and in SBF it was 0.34 microgram/ml. The median ratio of the areas under curves (f SBF/f serum) was 43%. In all subjects EES concentrations in SBF between the second and twelfth hours exceeded 0.1 g/ml. The results show good diffusion of EES through normal skin from the second to the twelfth hours after oral administration.

Adult

Predominance of capsular polysaccharide type 5 among oxacillin-resistant Staphylococcus aureus.

The relationship between capsular polysaccharide types 5 and 8 and resistance of Staphylococcus aureus to oxacillin was studied with a collection of 406 clinical isolates from six French hospitals. Of 175 type 5 isolates, 84 (48%) were resistant to oxacillin. In contrast, only 8 of 160 type 8 isolates (5%) and 5 of 71 nontypeable isolates (7%) were resistant to oxacillin. Therefore, capsular typing of clinical isolates of S. aureus may facilitate the choice of first-line antibiotic therapy.

Bacterial Capsules

[Eikenella corrodens infections].

E. corrodens is an anaerobic facultative Gram-negative rod whose natural habitat is the oral cavity and the upper respiratory tract. This work describes four new cases of verified infections associated with this bacterium. A literature review of cases from 1975 to 1984 has been made. In this report, we discuss the pathogenicity of E. corrodens and predisposing factors for infections including underlying diseases. Successful antibiotic therapy can be achieved with benzylpenicillin or ampicillin which are the drugs of choice. E. corrodens is a slow growing bacterium of low virulence, rarely isolated in current practice because of its unusual association with conditions such as human bites, infections of the oral cavity or immuno-suppressive therapy.

Adolescent