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Biomedical subjects

R Minck

Publications and source records attributed to R Minck.

At least 19 recordsLinked to original sources

Taxonomic study of Corynebacterium Group ANF-1 strains: Proposal of Corynebacterium afermentans sp. nov. containing the subspecies C. afermentans subsp. afermentans subsp. nov. and C. afermentans subsp. lipophilum subsp. nov.

We have determined the cell wall composition, guanine-plus-cytosine (G+C) contents of the DNA, rRNA gene restriction patterns, and the levels of DNA-DNA relatedness of 11 strains identified biochemically as Centers for Disease Control (CDC) Corynebacterium group absolute nonfermenter 1 (Corynebacterium group ANF-1). For seven of these strains, growth is abundant on 5% sheep blood agar, which differentiates them from the four other strains, whose growth requires a lipid supplement such as Tween 80. Two of the lipid-requiring strains produced mucoid colonies on 1% Tween 80-supplemented sheep blood agar. All strains possess cell wall component type IV, short-chain mycolic acids, and G+C contents of DNA of 66 to 68 mol% as determined by reverse-phase high-performance liquid chromatography. DNA-relatedness experiments by an S1 nuclease procedure showed that nine of these strains, including two of the lipid-requiring strains, constitute a new genomic species less than 40% related to Corynebacterium species and other coryneform groups. The lipid-requiring strain T18502 exhibited 98% DNA relatedness with another lipid-requiring strain, T88593 (difference in thermal denaturation midpoint [delta Tm] = 2 degrees C) and 71 to 77% similarity with the nonlipophilic strains (delta Tm range of from to 5 degrees C). Conversely, the DNA relatedness between strain LCDC 88199 and the six other nonlipophilic strains ranged from 86 to 100% (delta Tm range of from 1 to 3 degrees C) and was only 73 and 76% with the lipophilic strains T18502 and T88593, respectively (delta Tm, 3 and 4 degrees C). These results indicated that these two cultural types of bacteria constitute two subspecies within the new genomic species.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Typing Techniques↗

Coryneform bacteria isolated from middle ear fluid.

Nineteen strains of facultatively anaerobic gram-positive rods isolated in pure culture from middle ear fluids were identified. All effusions were collected by tympanocentesis in children with acute otitis media. Identification of microorganisms to the genus level was done by studying the cell wall composition. Sixteen strains contain meso-diaminopimelic acid and arabinogalactan polymer but lack mycolic acids; therefore, these strains do not belong to a previously described taxon. Because of similarities with Corynebacterium afermentans (Centers for Disease Control group ANF-1), we temporarily classified these mycolateless strains ANF-1 like. Isolation of these microorganisms in pure culture from middle ear fluids collected by tympanocentesis is a strong argument for their involvement in acute otitis media.

Actinomycetales↗

High-performance liquid chromatography of corynomycolic acids as a tool in identification of Corynebacterium species and related organisms.

A high-performance liquid chromatography (HPLC) study of 307 strains of Corynebacterium species and related taxa revealed that strains classified as "Corynebacterium aquaticum"; "Corynebacterium asperum"; and Centers for Disease Control (CDC) groups 1, 2, A-3, A-4, A-5, B-1, B-3, E, F-2, and I-2 as well as some unidentified coryneforms do not contain any corynomycolic acids; therefore, they should not be included in the genus Corynebacterium. Such an HPLC method of identification permitted the correct assignment to the genus Rhodococcus of two unpigmented strains of coryneform bacteria whose mycolic acid profiles were comparable to those of Rhodococcus equi. Bacteria belonging to CDC groups ANF-1, ANF-3, F-1, G-1, G-2, and I-1, as well as some other Corynebacterium sp. strains, yielded corynomycolic acid HPLC patterns related to those of Corynebacterium species. Either similarities or differences were observed in the corynomycolic acid profiles of Corynebacterium species tested after culture on sheep blood agar and/or sheep blood agar supplemented with Tween 80, which demonstrated that identification at the species or group level is possible. However, Corynebacterium striatum and CDC group I-1 bacteria as well as CDC group G-1 and group G-2 bacteria had indistinguishable HPLC patterns. Conversely, some variations were observed within some species as Corynebacterium xerosis, C. striatum, and Corynebacterium minutissimum. The evaluation procedure of this HPLC method by mass spectrometry analysis of isolated eluted peaks revealed that analytical reverse-phase HPLC alone does not provide any structural information, since isomers with identical polarities coeluted as a single peak. Nevertheless, HPLC is a rapid and reliable method for identification of corynomycolic acid-containing bacteria in the clinical microbiological laboratory.

Chromatography, High Pressure Liquid↗

[Current status of perioperative preventive use of antibiotics in colorectal surgery].

The rate of postoperative wound infections following colorectal surgery can be considerably reduced by rational perioperative short-time antibiotic prophylaxis. The anaerobic and aerobic microflora of the colon as well as the half-life of the medicaments used have to be taken into due consideration for good choice of antibiotics. Persistent orthograde intestinal flushing, using physiological electrolyte solution without any addition of antibiotics, on the eve of surgery as well as perioperative antibiotic prophylaxis "en flash", using slow-drop intravenous infusion of 1 g Ornidazole and 2 g Mezlocilline along with introduction of anaesthesia, made for a good approach to reducing wound infections following colorectal surgery to two per cent. Twice as much antibiotics were administered for 24 to 28 hours in emergency cases in which preoperative intestinal flushing was not possible. This helped to reduce the rate of postoperative infections from 32 to six per cent.

Anti-Bacterial Agents↗

Determination of alpha-amanitin and beta-amanitin in human biological fluids by high-performance liquid chromatography.

A high-performance liquid chromatographic assay of alpha-amanitin and beta-amanitin in human serum, urine, or stomach washings is described. Sample preparation involves a chemical step with deproteinization and organic solvent treatment, and a selective cleanup and concentration step on reversed-phase prepacked cartridges. Separations are performed on a reversed-phase analytical column under isocratic conditions with uv detection at 280 nm. The method allows the quantitation of alpha- and beta-amanitin separately with a detection limit of 10 ng/ml for both toxins.

Amanitins↗

High-performance liquid chromatographic method for determination of ciprofloxacin in biological fluids.

A simple and precise high-performance liquid chromatographic procedure has been developed for the determination in biological fluids of ciprofloxacin, a new, with extended antibacterial spectrum, quinoline carboxylic acid. The work-up procedure involves a chemical extraction step followed by isocratic chromatography on a reversed-phase analytical column, with ultraviolet detection. The detection limit for blood levels is 10 ng/ml. The calibration curve is linear from this detection limit to 10 microgram/ml. The statistical analysis of the correlation made between this assay and an agar diffusion procedure during a pharmacokinetic study suggests the existence of one or more active metabolites which could be mainly excreted in the bile.

Anti-Infective Agents↗

[HPLC study of the pharmacokinetics of mezlocillin administered by 30-minute infusion and comparison with the direct intravenous route].

Mezlocillin pharmacokinetics were investigated in eighteen patients from a surgical service after a 30 minutes infusion with the purpose, on one hand, to compare this way of administration with a bolus intravenous infusion, and on the other hand to confirm or invalidate capacity-limited dose-dependent pharmacokinetics. Dosages were 2 g (n = 8) and 5 g (n = 10). Mezlocillin levels were measured by high performance liquid chromatography. Calculated data obtained with the 30 minutes infusion are different from those resulting from a bolus infusion. Peak levels, alpha and beta are lower ; T 1/2 beta, areas under the curve, and distribution volumes are higher. Most of the calculated data were not in agreement with a capacity-limited kinetic at the two studied dosages. The two regression-lines (2 g and 5 g) of mezlocillin body clearance versus creatinine clearance superimpose exactly. The 30 minutes infusion, and important hemodynamic variations between our 18 patients may partly explain the differences between our data and those published in the literature.

Adult↗

C-reactive protein measurement: a reliable method of diagnosing and monitoring the infected newborn for the assessment of a mezlocillin therapeutic trial.

Clinical and bacteriological efficacy of mezlocillin was evaluated in 41 neonates (including 12 premature babies) with clinical and laboratory evidence of bacterial infection, as shown by elevated C-reactive protein serum concentrations. They received intravenous mezlocillin (80 to 100 mg/kg/dose) every 8 h for 10.4 days. The mean serum concentration (+/- S.E.M.) of mezlocillin in full-term neonates was 214 +/- 19.8 mg/l 1 h after the infusion and 52.0 +/- 9.3 mg/l prior to the next infusion. In premature neonates these mean concentrations were respectively 167 +/- 23.4 mg/l and 40.7 +/- 6.7 mg/l. The efficacy of mezlocillin was documented by the decrease in C-reactive protein serum concentrations and by improvement in clinical condition. Therapy with mezlocillin alone proved to be safe and effective when used for non-nosocomial infections during the neonatal period.

Bacteria↗

[Focus and value of the assay of 5 beta-lactams using high-performance liquid chromatography].

Severe infectious diseases treatment often needs a frequent antimicrobial agent blood levels control. These controls are still performed by microbiological assay procedure. High performance liquid chromatography (HPLC) is now allowing a new kind of assay procedure and improves on speed, specificity and sensitivity. We developed a procedure allowing us to monitor every day by routine, five beta-lactam antibiotics with only one analytical column: benzylpenicillin, ampicillin, cloxacillin, mezlocillin and cefotaxime. A single extraction procedure suitable to the five beta-lactam antibiotics and to various body fluids and the use of three mobile phases, permit us to give a quick answer to the clinicians and thus to consider a rapid adaptation of the doses being administered. In consideration of the specificity, it is possible to control blood levels of each beta-lactam antibiotic even by associated antimicrobial treatment, what is sometimes impossible using the microbiological assay procedure. Cefotaxime is well separated from its active metabolite desacetyl-cefotaxime. The disparity of the levels obtained, for the same posology, essentially by prematures and new-borns, but also in case of massive infusions for endocarditis justify the use of a rapid and specific procedure like high performance liquid chromatography (HPLC).

Anti-Bacterial Agents↗

[Exfoliatin in neonatal staphylococcal infections].

An outbreak of staphylococcal skin infection in neonates was investigated clinically, bacteriologically and epidemiologically with the following findings: (1) In 8 out of 13 cases, exfoliatin-producing staphylococci were present in the bullae, which is unusual with bullous lesions occurring at other ages; (2) exfoliatin producing staphylococci were present in all children with bullous lesions, as well as in carriers; (3) 39% of the phage II group staphylococci studied produced exfoliatin; (4) purulent lesions due to phage II staphylococci which did not produce exfoliatin were observed. The contaminating agent could be identified in most cases.

Animals↗

Penicillin-binding proteins and carboxypeptidase/transpeptidase activities in Proteus vulgaris P18 and its penicillin-induced stable L-forms.

The originally penicillin-induced, wall-less stable L-forms of Proteus vulgaris P18, isolated by Tulasne in 1949 and since then cultured in he absence of penicillin, have kept the ability to synthesize the seven penicillin-binding proteins and the various DD- and LD-peptidase activities found in the parental bacteria and known to be involved in wall peptidoglycan metabolism. The stable L-forms, however, secrete during growth both the highly penicillin-sensitive, DD-carboxy-peptidase-transpeptidase penicillin-binding protein PBP4 (which in normal bacteria is relatively loosely bound to the plasma membrane) and the penicillin-insensitive LD-carboxypeptidase (which in normal bacteria is located in the periplasmic region).

Bacterial Proteins↗

[Utility of serotyping in the study of Serratia marcescens infections in Strasbourg Hospitals (author's transl)].

A total of 1,499 Serratia marcescens strains were isolated in Strasbourg University Hospital within a period of three years. Serotyping could split this collection into 37 different serotypes. Two serotypes (014:H12 and 013:H17) were responsible for a persistent S. marcescens endemic. Serotype 014:H12 was mostly recovered from sputa, whereas serotype 013:H17 was mostly recovered from urine. These two serotypes had different antibiotic resistance patterns.

Cross Infection↗