Rapid detection of members of the family Enterobacteriaceae by a monoclonal antibody.

Six monoclonal antibodies directed against enterobacteria were produced and characterized. The specificity of one of these antibodies (CX9/15; immunoglobulin G2a) was studied by indirect immunofluorescence against 259 enterobacterial strains and 125 other gram-negative bacteria. All of the enterobacteria were specifically recognized, the only exception being Erwinia chrysanthemi (one strain tested). Bacteria not belonging to members of the family Enterobacteriaceae were not detected, except for Plesiomonas shigelloides (two strains tested), Aeromonas hydrophila (five strains tested), and Aeromonas sobria (one strain tested). This recognition spectrum strongly suggested that CX9/15 recognized the enterobacterial common antigen. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) experiments, the six antienterobacteria antibodies presented similar specificities; they all revealed only one band with an apparent molecular weight of about 20,000 from the crude extract of an enterobacterium. The six monoclonal antibodies, and especially CX9/15, can be used to develop new tests for rapid and specific detection of enterobacteria.

Identification of Pseudomonas, Flavobacterium, and Alcaligenes with the API 20 NE system.

The API 20 NE system is designed for the rapid identification of Gram negative rods other than Enterobacteriaceae. It has been compared to conventional methods in the characterization of 404 strains representative of 23 species belonging to 3 genera: Pseudomonas (236 strains), Flavobacterium (133 strains) and Alcaligenes (35 strains). The system consists of 9 enzymatic tests and 12 carbohydrate assimilation tests. A 7-digit numerical profile is obtained by an octal coding of the test results. The strains are identified by comparing the numerical profile to those of species listed in a profile index. The API 20 NE tests showed 99-100% correlation with corresponding conventional methods except in indole production (96.5%) for which we observed 14 false negative reactions in testing F. meningosepticum and CDC groups IIb and IIf. The API 20 NE system presented 94.1% identification to the species level and 96.3% to the genus level in agreement with conventional biochemical methods. Among the correctly identified strains, 7.4% (30) gave an erroneous or unlisted numerical profile in the first version of the Profile Index and required the use of the computer. Among the misidentified strains 2%, (8) were assigned to the right genus but wrong species, 0.7% (3) were placed in the wrong genus and 1% (4) gave a doubtful profile with one or more tests compared to the profiles listed.

Characterization of Flavobacterium species by analysis of volatile fatty acid production.

Seventy-four Flavobacterium strains were characterized by gas-liquid chromatographic analysis of volatile fatty acids produced in the culture medium. Principal components analysis permitted the graphic representation of the relative positions of the different strains, and aggregation according to the variance enabled a hierarchical classification to be established. The study revealed three subgroups each for F. meningosepticum and F. odoratum. Our F. breve, Flavobacterium sp. group IIb and F. multivorum strains appeared to be homogeneous. These results tallied with those of previous studies on DNA base composition and reassociation, electrophoretic protein profiles and cellular fatty acid composition.

[Ciprofloxacine: evaluation of its biliary elimination in man]. / Ciprofloxacine: évaluation de son élimination biliaire chez l'homme.

To investigate the possibility of therapeutic use of ciprofloxacin in infections of the biliary tract, the serum and bile kinetics, and the biliary, urinary and fecal elimination of this new broad-spectrum quinolone were studied in 12 recently cholecystectomized patients with T-tube drainage. Ciprofloxacin concentrations were determined by simultaneously performed HPLC and microbiological assay in serum, urine, and bile over a 24-hour period following oral administration of a single dose of 500 mg of the drug. The two methods yielded similar values both in the serum and in the urine. Average peak serum concentrations were 0.97 +/- SEM 0.17 microgram/ml (HPLC) and 1.08 +/- 0.19 microgram/ml (microbiological assay) (NS). The respective mean urinary concentrations in the first 6-hour sample were 267 +/- 74 micrograms/ml and 241 +/- 58 micrograms/ml (NS). In bile, however, the microbiological assay gave higher values than HPLC:average peak concentrations of 10.3 +/- 3.4 micrograms/ml and 7.5 +/- 2.8 micrograms/ml (p less than 0.02) respectively, reached during the 2nd hour after drug administration, and mean total 24-hour biliary ciprofloxacin output of 2167 +/- 288 micrograms and 1587 +/- 222 micrograms (p less than 0.01) respectively. This may point to hepatic transformation of ciprofloxacin to more active metabolite(s) than the parent compound. The significantly higher concentrations of ciprofloxacin in bile than in serum exceeded the minimum inhibitory concentration for organisms usually responsible for biliary infections. These infections may, therefore, be favorably affected by ciprofloxacin.

Discriminant analysis of volatile fatty acids produced in culture medium: a novel approach to the identification of Pseudomonas species.

The volatile fatty acids produced in culture medium by 357 Pseudomonas strains belonging to eight species were determined quantitatively by GLC. The resultant chromatograms were submitted to discriminant analysis. Stable discriminant functions were computed and included in a computerized identification system which also involved some distinctive volatile fatty acids regarded as two-state qualitative characters (presence or absence characters). Using a test group of 249 strains belonging to the studied species, more than 89% of the identifications made by this system agreed with those made by conventional biochemical methods despite the relatively poor differentiation between P. putida and P. fluorescens. When the individual species within the matrices were weighted with prior probabilities reflecting results given by two simple biochemical tests, 96% of the 249 strains were correctly identified.

[Taxonomic value of the characterization of Pseudomonas by the analysis of volatile fatty acids produced in culture]. / Intérêt taxonomique de la caractérisation des Pseudomonas par l'analyse des acides gras volatils produits en culture.

Gas liquid-chromatography was used in order to characterize the volatile fatty acids produced in culture supernatants by 632 Pseudomonas strains. Statistical analysis of these results allowed testing of the discriminatory power of this analytical methodology (factor analysis) to point out the presence of subgroups (clustering according to the variance) and to show the relationship between species and subspecies (three-dimensional plot). Fourteen Pseudomonas species could be accurately characterized by this methodology; the classification of Pseudomonas build up, on the basis of qualitative and quantitative aspects of their volatile fatty acids production, agrees with the current classification based on rRNA/DNA homology complexes.

[Gas chromatographic study of volatile fatty acids produced by 14 species of Pseudomonas]. / Etude par chromatographie en phase gazeuse des acides gras volatils produits par quatorze espèces de Pseudomonas.

A quantitative gas-liquid chromatographic method for the determination of the volatile fatty acids produced in standardized liquid culture media by Pseudomonas reference strains belonging to 14 species, some of medical interest, is proposed here. This method, using 14 reference strains, permitted a precise identification of Pseudomonas species according to characteristic chromatograms. The key used for this identification gave us a classification corresponding to the DNA homology groups.

[Comparative activity of azlocillin on Pseudomonas species excluding Pseudomonas aeruginosa]. / Activité comparée de l'azlocilline sur Pseudomonas species à l'exception de Pseudomonas aeruginosa.

The minimal inhibitory concentrations (MIC) of three acylureidopenicillins (azlocillin, mezlocillin, piperacillin) and three third generation cephalosporins (cefotaxime, cefoperazone, cefsulodin) against 249 randomized strains of Pseudomonas spp. representing 10 species other than Pseudomonas aeruginosa, were determined by the agar dilution method in Mueller-Hinton agar and compared by parametric statistical tests. Fresh clinical and environmental hospital isolates belonged to the following species: P. fluorescens (35), P. putida (37), P. stutzeri (17), P. mendocina (4), P. cepacia (37), P. pickettii (22), P. acidovorans (36), P. diminuta (5), P. paucimobilis (23), P. maltophilia (37). Azlocillin inhibited over 88% of Pseudomonas spp at 64 mg/l or less. This good antipseudomonal activity in vitro was comparable to those of piperacillin and cefotaxime with a minimal inhibitory concentrations 50 value of 8 mg/l. Against these Pseudomonas spp, the ranking order of activity was azlocillin = piperacillin = cefotaxime greater than cefoperazone greater than mezlocillin greater than cefsulodin. Like piperacillin or cefotaxime, azlocillin, was effective against ticarcillin--and aminoglycoside--resistant Pseudomonas spp. Against P. maltophilia and P. cepacia, the two Pseudomonas spp other than P. aeruginosa that are important pathogens in opportunistic infections and in their vast majority are resistant to amino glycosides, azlocillin was significantly active. Only in the case of P. maltophilia, cefoperazone had a lower minimal inhibitory concentrations 50 (8 mg/l vs. 32 mg/l).