Serological and molecular comparison of Mannheimia haemolytica and Pasteurella trehalosi strains isolated from wild and domestic ruminants in the French Alps.

Over a period of 17 years, 84 bacterial isolates identified as Mannheimia haemolytica or M. glucosida, and 52 isolates identified as Pasteurella trehalosi were detected in the lungs of domestic and wild ruminants in the French Alps. The isolates were serotyped according to their surface capsular antigens, and those sharing common antigens were further characterized by pulsed field gel electrophoresis. The results showed that the bacterial isolates included in the study clustered according to the host species from which they were isolated. These findings indicate that the transmission of serotypes of M. haemolytica, M. glucosida or P. trehalosi from an animal host in which they are common to another species sharing the same geographical space may be a rare epidemiological event.

Bacterial flora in foals with upper respiratory tract infections in Poland.

Bacteria isolated from nasal cavity of 80 foals with upper respiratory tract infection, as well as from 20 healthy foals, were examined. Within the group of sick animals, from 18 (22.5%) bacteria with recognized pathogenicity were isolated. Coagulase-negative staphylococci and Acinetobacter sp. were the dominant species identified (100 and 45%, respectively). No bacteria species with recognized pathogenicity were isolated from the group of healthy animals. Three cases of death within the group of sick foals were investigated. Rhodococcus equi in two cases and Klebsiella pneumoniae pneumoniae together with Escherichia coli were isolated post-mortem from lung abscesses.

Allophycocyanin 1 as a near-infrared fluorescent tracer: isolation, characterization, chemical modification, and use in a homogeneous fluorescence resonance energy transfer system.

Allophycocyanin 1 (APC1), isolated from Mastigocladus laminosus, retains the same (alpha-beta)(3) trimeric structure as allophycocyanin (APC), but incorporates a peptide linker in its core leading to a 28% increase in its fluorescence quantum yield compared to APC. Moreover, APC1 exhibits an unexpectedly good stability at very low concentrations, at extreme pHs, or diluted in a low ionic strength medium whereas, under the same conditions, APC dissociates into an (alpha-beta) monomer, indicating that the peptide linker acts as a stabilizer of its trimeric structure. APC1 crosslinking experiments performed using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide gave a high reaction yield (95%) and showed a similar crosslinking process as previously described for APC. Fluorescence quantum yields of crosslinked APC1 or APC decrease by 20% after labeling on antibody or streptavidin. However, quantum yields of the crosslinked APC1 conjugates remain 25% higher than those of crosslinked APC conjugates. Associated with a europium trisbipyridine cryptate as donor, crosslinked APC1 was compared with crosslinked APC as acceptor in homogeneous time resolved fluorescence technology based on a fluorescence resonance energy transfer process. Using crosslinked APC1, assay performances were increased by 20%, showing that APC1 could be considered as a very promising near infrared fluorescent probe to replace APC in its biological applications.

A new long acting ophthalmic formulation of carteolol containing alginic acid.

Alginic acid was evaluated as a potential vehicle in ophthalmic solutions for prolonging the therapeutic effect of carteolol. This anionic vehicle was expected to slow down drug elimination by the lacrimal flow, both by undergoing in-situ gel formation and by interacting with the mucus. In vitro studies indicated that carteolol is released slowly from alginic acid formulations, suggesting an ionic interaction. The adhesive behavior of alginic acid solution was better than that of another polymer, hydroxyethylcellulose (HEC). Intraocular pressure (IOP) measurements of rabbit eyes treated with a 1% carteolol formulation with or without alginic acid showed that this polymer significantly extended the duration of the pressure-reducing effect of carteolol to 8 h. The increased ocular bioavailability of 1% carteolol in the presence of alginic acid led to an equivalent concentration in the target tissue although administration was only once a day compared with twice a day for 1% carteolol alone. The overall results of this study indicate that the alginic-acid vehicle is an excellent drug carrier, well tolerated, and could be used for the development of a long-acting ophthalmic formulation of carteolol.

Ribotyping and rapid identification of Staphylococcus xylosus by 16-23S spacer amplification.

Ninety-five strains of Staphylococcus xylosus isolated from goat milk, French sausage or mice were analyzed together with 35 Staphylococcus type strains by 16-23S spacer amplification and ribotyping. The results obtained by PCR amplification of the 16-23S spacer region permitted the distinction of each type strain and additionally generated a DNA banding pattern characteristic for 93 of the 95 Staphylococcus xylosus strains. Ribotyping proved to be an efficient epidemiological tool for Staphylococcus xylosus species as it clustered the 95 strains into 23 distinct types.

Identification by 16S rDNA fragment amplification and determination of genetic diversity by random amplified polymorphic DNA analysis of Pasteurella pneumotropica isolated from laboratory rodents.

Pasteurella pneumotropica is an opportunistic bacterium frequently isolated from colonies of various laboratory rodents. Identification of this species, including its differentiation into two distinct biotypes (Jawetz and Heyl), is usually based on the use of conventional bacteriologic methods. In this study, a 16S rDNA fragment amplification procedure was developed for use as an alternative method for identification and differentiation of P. pneumotropica. Polymerase chain reaction (PCR) products were two distinctive fragments of 937 and 564 bp specific for biotypes Jawetz and Heyl, respectively. Specificity of PCR products could be achieved by EcoRI cleavage, leading to 596 plus 341-bp and 346 plus 218-bp fragments for each of the amplification products. Use of this procedure confirmed identification of 34 field isolates and allowed definitive identification of some strains that could not have been done by use of bacteriologic examinations. Field isolates subjected to random amplified polymorphic DNA (RAPD) analysis had high genetic diversity among biotype Jawetz strains in contrast to biotype Heyl strains. In conclusion, RAPD could represent an additional means for identification of ambiguous strains of biotype Heyl and a valuable epidemiologic tool for identification of biotype Jawetz strains of P. pneumotropica.

Pulsed-field gel electrophoresis is more efficient than ribotyping and random amplified polymorphic DNA analysis in discrimination of Pasteurella haemolytica strains.

One hundred thirty-three strains of Pasteurella haemolytica of both biotypes (90 and 43 strains of biotypes A and T, respectively) and almost all the serotypes were subjected to ribotyping, random amplified polymorphic DNA (RAPD) analysis, and pulsed-field gel electrophoresis (PFGE) analysis for epidemiological purposes. A total of 15 patterns recorded as ribotypes HA to HO were found for the P. haemolytica biotype A strains, with ribotypes HA, HC, and HD being encountered most often (66 strains [74%]); and 20 ribotypes, designated HA' to HT', that were clearly distinct from those observed for biotype A strains were observed for strains of biotype T. RAPD analysis generated a total of 44 (designated Rp1 to Rp44) and 15 (designated Rp1' to Rp 15') unique RAPD patterns for biogroup A and biogroup T, respectively. Analysis of the data indicated that a given combined ribotype-RAPD pattern could be observed for biotype A strains of different serotypes, whatever the zoological or geographic origin, whereas this was not the case for biotype T strains. PFGE appeared to be more efficient in strain discrimination since selected strains from various zoological or geographical origins harboring the same ribotype-RAPD group were further separated into unique entities.

[Constrictive pericarditis: an underestimated complication of thoracic injuries]. / La péricardite constrictive: une complication sous-estimée des traumatismes thoraciques.

Constrictive pericarditis is a well defined clinical entity, traditionally secondary to longstanding tuberculosis. Although posttraumatic constrictive pericarditis, due to haemopericardium, is well known during the postoperative period following cardiac surgery, it is underestimated in closed chest trauma. A new case of constrictive pericarditis is reported, due to neglected chest trauma. The discussion emphasizes the need for early diagnosis and surgical treatment, which determine the general prognosis of pericardial constriction. This implies systematic investigation of all cases of chest trauma, even minor, by transthoracic, or preferable, transoesophageal echocardiography, looking for haemopericardium.

Influence of sterilization processes on poly(epsilon-caprolactone) nanospheres.

Polymeric vectors and especially poly(epsilon-caprolactone) nanoparticles have already shown promising results in the optimization of the ophthalmic bioavailability of drugs. Any formulation instilled in the eye must be sterile, and preferentially isotonic. Poly(epsilon-caprolactone) nanospheres were thus formulated with Synperonic PE/F68, Synperonic PE/F127, or Cremophor RH40. A tonicity agent, a preservative and, in some cases, a viscosifiant were then added. The pH was finally adjusted to pH 4 or buffered to pH 7. Different sterilization processes were studied to investigate their influence on the physicochemical characteristics of vectors. Autoclaving did not induce any modification on polymer molecular weight or Synperonic nanospheres diameter, but catalysed some reactions with surfactants and tonicity agents. This method could thus be used if the nanosphere excipients are chosen with care. gamma radiation induced preservative degradation and viscosifiant depolymerization. A cross-linking of poly(epsilon-caprolactone) chains was observed, as reflected by a sharp increase of its molecular weight. However, no variation of the mean particle size was detected. Finally, sterile filtration was the only process which ensured the conservation of physicochemical integrity of nanospheres. This process was successfully applied on non-viscosified vectors with a sufficiently small diameter.