PubMed Health⌕ Search

Biomedical subjects

G Carret

Publications and source records attributed to G Carret.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Effect of subinhibitory concentrations of antibiotics on the growth level of bacteria].

The effect of subinhibitory concentrations of 5 antibiotics on the growth rate of 2 bacteria (Staphylococcus aureus and Escherichia coli) has been studied. Chloramphenicol, dibekacin, netilmicin and nalidixic acid have a direct effect on the growth rate. Apparently, aminoglycosides and nalidixic acid have an accompanying effect on the affinity for the energizing substrate. Amoxicillin does not seem to be concerned by this 2 mechanisms. The interest of the estimation of the growth rate by an adaptative algorithm has been pointed out.

Anti-Bacterial Agents↗
PubMed1986

[Evaluation of the Rapid-ATB system for testing the sensitivity of staphylococci to antibiotics. Comparison with the agar dilution reference method].

Rapid ATB Staph is a new, automated, four-hour procedure for testing the susceptibility to antibiotics of staphylococci. Results obtained with this method were compared to those recorded using agar dilution. For all tested antibiotics as a group (5 on 201 strains, 8 on 100 strains), overall agreement between the two sets of results was 96%. 1,809 susceptibility tests were performed, with only 24 minor discrepancies (1.3%) mainly involving cotrimoxazole, and 50 major discrepancies (2.7%) mainly involving doxycycline and chloramphenicol. Rapid ATB Staph clearly demonstrates the heterogeneous oxacillin-resistance of staphylococci as well as their inducible resistance to erythromycin. Our results show that this new system is a very accurate means for testing the susceptibility to antibiotics of staphylococci.

Anti-Bacterial Agents↗
PubMed1985

[Rapid ATB. A new system of antibiotic testing in 4 hours. Description and parameters of variation].

Rapid ATB is a new automated system which performs antibiotic sensitivity testing of Enterobacteriaceae in four hours. It is composed of strips containing dehydrated antibiotics and a medium which ensures rapid bacterial growth, and of the equipment required for standardization of the inoculum, reading of results and interpretation. Strains are classified as susceptible or resistant according to the value of the growth index (IC) which is the ratio of growth in the presence of the antibiotic to growth of a control inoculum. Use of this system requires standardization. The main factors to control are state of the culture used to prepare the inoculum, standardization of the inoculum, incubation temperature (35 to 37 degrees C), and duration of incubation (4 to 5 hours). Variations of these factors usually induce significantly delayed growth. Under well standardized conditions, results are highly reproducible, as proved by testing ten strains ten times each by three investigators.

Culture Media↗
PubMed1985

[The bacteriology laboratory of tomorrow].

The development of needs and the conditions for performing examinations in clinical bacteriology leads us to consider that bacteriological analysis should eventually: be closer to clinical requirements. This results in an accelerated bacteriology (whose response-times approach those of other biological specialties) and in a consideration of the diagnostic and therapeutic importance of the response; be less costly. This leads to an increase in productivity, and involves an introduction of computers, automatic systems for antibiograms and identification, and appropriate and inexpensive bioreagents; consider the requirements of the technicians in order to avoid diminishing the interest of the work. This development demands a recognition of needs, whether expressed or not, and a rejection of olds habits that are not adapted to the requirements of a bacteriology which is closer to the patient, quicker, and finally, less costly.

Bacterial Infections↗
PubMed1984

[Staphylococcal toxic shock syndrome].

The case of a 31 year old woman with staphylococcal toxic shock syndrome is reported. The usual clinical characteristics were found: it began during a menstrual period, and she presented with a state of shock, a high fever and a cutaneous eruption. Its evolution was marked by pulmonary interstitial oedema and acute renal failure requiring dialysis; the patient recovered but residual renal failure was still present four months later. A Staphylococcus aureus was isolated from vaginal, nasal and tracheal cultures. It produced enterotoxins A and F, which were responsible for the symptoms.

Acute Kidney Injury↗
PubMed1984

[Nonparametric approach to the determination of critical diameters. Comparison with conventional methods].

Bacteria are usually classified as susceptible (S), intermediate (l) or resistant (R) by comparison of their MICs with two reference MIC cutoff levels. Three sets Sc, Ic and Rc are thus constructed. By using agar diffusion, the same bacteria are classified as Sd, Id or Rd, by comparison of inhibition zone diameters with two reference diameter breakpoints. These Sd, Id and Rd sets are not absolutely identical with Sc, Ic and Rc respectively. Diameter breakpoints were submitted to successive adjustments until minimal differences were achieved, i.e. when the greatest possible number of elements was included in the sets: (Formula: see text) Comparison of this method with more conventional techniques emphasizes its value.

Ampicillin↗
PubMed1983

[Value of the study of fibrinogen affinity in the identification of Staphylococcus aureus. Results of a multicenter study].

The passive haemagglutination reaction for detecting the Staphylococcus aureus fibrinogen affinity was done in a collaborative study. The test was compared to the major tests used in medical microbiology. The test was as efficient as the protein A or coagulase tests. Its simplicity, rapidity and specificity make it a useful tool for the diagnosis of this species.

Fibrinogen↗
PubMed1983

[Comparison of the results of antibiograms obtained from blood culture broth and after isolation on agar media with the Autobac 1].

The authors compare the results of antibiotic sensitivity tests performed within 4 hours with the aid of the Autobac 1 machine, using blood culture medium and following isolation on agar plates. There was concordance in about 90 p. cent of cases. The first test is not suitable for sensitivity to trimethoprim and the beta-lactamines, as was already observed in the study using the MS-2 machine. The authors discuss the various sources of error and compare the results obtained from the two machines.

Agar↗
PubMed1983

[Evaluation of a rapid technic for antibiotic sensitivity testing: reproducibility of minimal inhibitory concentrations routinely estimated with the use of Abbott MS-2 autoanalyzer].

The inter-system reproducibility of the MIC results obtained from the MS-2 automated system of antibiotic sensitivity testing was assessed by a two-stage study. In the first stage, a total of 168 MICs were calculated by the automated system from 134 diverse bacterial strains, selected from routine antibiotic sensitivity testing for their "intermediate" sensitivity to one or more antibiotics. The antibiotic sensitivities were repeated using the same machine, in the same laboratory, on another suspension of the same bacteria. The results of antibiotic sensitivity reported as "intermediate" on the first test were compared to those of the second test; only 19 p. cent of the responses remained "intermediate" and the MICs were comparable between the two tests; 50 p. cent became sensitive and 31 p. cent became resistant (MIC not calculated). In the second stage, 4 strains with stable intermediate sensitivity to 8 antibiotics, as shown by 2 routine sensitivity tests, were tested 33, 48, 44, and 39 times respectively against these antibiotics using various suspensions of the same strain. 394 results were obtained: 92 intermediate results with a MIC (24.4 p. cent), 219 sensitive results (56.3 p. cent) and 83 resistant results (20.2 p. cent). The range of values for the MIC calculated by the automatic system was small, so the MICs are reproducible; but, for 5 of the 8 antibiotics, the responses were both "S" and "R". This suggests that the so-called "Intermediate" zone is in fact a zone of uncertainty where the majority of the MIC results are erroneous.

Anti-Bacterial Agents↗
PubMed1982

[Automation of antibiograms. Effect on the response delay of bacteriologic tests].

The delay between in-coming requests and results of bacteriological examinations was measured in a hospital laboratory before and after automation with an Abbott MS-2 system. Paradoxically, using this apparatus, which performs certain tasks within 6 hours instead of 12, increased the delay, mainly because of the multiple problems associated with automation. On the other hand, the delay was significantly reduced when a rapid micro-organism identification method (Micro ID) was used concomitantly. It is concluded that maximum efficiency could be achieved if bacteriological laboratories combined automated antibiotic susceptibility testing with a rapid germ identification method.

Anti-Bacterial Agents↗
PubMed1982

Serological grouping of streptococci: a collective evaluation in six laboratories of three rapid methods.

Three serological methods for streptococci grouping: latex agglutination after pronase extraction (LAP), latex agglutination after nitrous acid extraction (LAN) and counterimmunoelectrophoresis after nitrous acid extraction (CIEN) were evaluated in six laboratories with 310 strains of streptococci. To reduce the possible influence of a particular laboratory, each serological procedure was performed in two different laboratories with identical protocols and strains. Between the three procedures, a total agreement of 81.3% with six identical results was obtained. Since only one discordant result was obtained in 12.2% (CIEN 4.8%-LAN 5.8%-LAP 1.6%) and two discordant results with two different serological methods in 2.6%, it could be concluded that agreement between the three procedures was 96%. For B (99 strains tested) and D(100 strains tested) groups, total agreements of respectively 95% and 92% were achieved. In conclusion, LAP, LAN, and CIEN gave equivalent results for streptococci grouping, but LAN was the most simple needing no heating, centrifugation, or electrophoresis equipment and lacking cross-reactivity of group C antibody.

Counterimmunoelectrophoresis↗
PubMed1982

Evaluation of Salmonella and Shigella identification with the MS2-BID automatic system.

The precision of the Abbott MS-2 system was evaluated for the rapid identification of Salmonella and Shigella strains in 5 hours. The results of 113 strains of Salmonella and 52 strains of Shigella studied showed a total agreement of 68% and 90% respectively with the API 20E method and with sero-agglutination taken as reference. But in 12.40% and 2% of the cases the Salmonella and Shigella strains were not recognised and no warning message was given by the automate. Moreover, during the daily utilisation of the apparatus, the 21 strains labelled Shigella and Salmonella were later shown to belong to other genera. The MS-2 BID system is therefore of limited interest in medical and in food microbiology.

Amino Acids↗
PubMed1981

Study of the staphylococcal affinity to fibrinogen by passive hemagglutination: a tool for the Staphylococcus aureus identification.

Cadness-Graves et al. used a slide agglutination reaction with human plasma to identify Staphylococcus aureus. The clumping factor (CF) is responsible for this reaction by reacting directly with the fibrinogen. To increase the sensitivity and the specificity of the reaction and the taxonomic value of the test based on the CF detection, a passive hemagglutination has been developed and applied on 580 staphylococcal strains. Formolized sheep red cells were sensitized with human fibrinogen. This reaction has been compared to the classic plasma slide test. The hemagglutination test is more suitable and more precise than the plasma slide test. The detection of staphylococcal affinity to fibrinogen using the passive hemagglutination reaction is a method which is simple and specific, and therefore of obvious interest in taxonomic studies.

Coagulase↗
PubMed1981

[Evaluation of a rapid technique for antibiotic sensitivity testing using an MS-2 automate and blood culture medium].

The authors propose a rapid method for studying antibiotic sensitivity of bacteria isolated from blood cultures. An MS-2 automate is used directly with bacteria collected after centrifugation. With the exception of the sensitivity of Gram-positive cocci to the combination of sulfamethoxazole-trimethoprime and to Penicillin G and of Gram-negative bacillus to beta lactamines, the results were comparable to those obtained after isolation of bacteria on gel medium. Various causes for error are discussed.

Anti-Bacterial Agents↗