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PubMed1999

A-protein from achromogenic atypical Aeromonas salmonicida: molecular cloning, expression, purification, and characterization.

Achromogenic atypical Aeromonas salmonicida is the causative agent of goldfish ulcer disease. Virulence of this bacterium is associated with the production of a paracrystalline outer membrane A-layer protein. The species-specific structural gene for the monomeric form of A-protein was cloned into a pET-3d plasmid in order to express and produce a recombinant form of the protein in Escherichia coli BL21(DE3). The induced protein was isolated from inclusion bodies by a simple solubilization-renaturation procedure and purified by ion exchange chromatography on Q-Sepharose to over 95% pure monomeric protein. Recombinant A-protein was compared by biochemical, immunological, and molecular methods with the A-protein isolated from atypical A. salmonicida bacterial cells by the glycine and the membrane extraction methods. The recombinant form was found to be undistinguishable from the wild type when examined by SDS-PAGE and gel filtration chromatography. The immunological similarity of the protein samples was demonstrated by employing polyclonal and monoclonal antibodies in ELISA and Western blot techniques. All forms of A-protein were found to activate the secretion of tumor necrosis factor alpha from murine macrophage. To date, this represents the first large-scale production of biologically active recombinant A-protein.

Aeromonas↗
PubMed2004

Identification of an atypical form of 30 kDa SOD--a possible virulence factor in clinical isolates of Shigella spp.

Reviews on the pathogenic mechanisms of Shigella species show a lacunae in the understanding of the bacterial antioxidant defense system and its regulations. This study was done to investigate the regulation of expression of antioxidant enzymes in clinical isolates of Shigella species, under various growth conditions. The in vitro expression of superoxide dismutase in the clinical isolates of Shigella spp., is modulated by both endogenous and exogenous factors. During aerobic and iron repleted growth conditions, the expression of the MnSOD and FeSOD enzymes were higher, and an atypical SOD was also expressed. However, under anaerobic growth conditions and in plasmid-cured strains, the antioxidant enzyme activities were decreased and the atypical SOD was not expressed. Absence of the atypical form of SOD may be due to the low oxygen environment. Plasmid-encoded factors may also play a role in the expression of this SOD, which had a molecular weight of approximately 30 kDa. In the rat ileal loop ligation assay, mild lesions were observed only in the intestinal microvilli of rats injected with plasmid-cured strains of Shigella spp., suggesting that plasmid-encoded factors, including those that regulate the expression of the atypical SOD, are essential for the virulence of Shigella spp.

Animals↗
PubMed2006

[The pathogens of atypical respiratory infections and asthma].

The pathogens of atypical respiratory infections form a big heterogeneous group of different microorganisms. The classical ones belong to bacterial species of Mycoplasma pneumonaie, Chlamydia pneumoniae and Legionella pneumophila. This category comprises also some viruses and rickettsia. In many cases they are responsible for the asthma course exacerbation. Their contribution in the asthma development is suspected, too. Potential protecting effect against atopy and asthma is a subject of speculations. The authors discuss all three aspects, reporting own observations. A precise determination of the role of atypical infection in asthma remains to be determined.

Asthma↗
PubMed2006

Atypical growth of Renibacterium salmoninarum in subclinical infections.

Two growth types of Renibacterium salmoninarum were isolated from subclinically infected rainbow trout, one producing the smooth colonies typical of R. salmoninarum and the other forming a thin film on the surface of the agar with no separate colonies. The atypical growth was present on kidney disease medium agar in primary cultures of the kidney but not on selective kidney disease medium (SKDM). Fluorescent antibody staining of the fresh isolate and polymerase chain reaction amplification were the most reliable techniques to identify the atypical growth of R. salmoninarum. The condition was reversible, with growth reverting from atypical to the smooth colony form in experimentally infected rainbow trout and under laboratory conditions. There was no mortality, or any clinical signs of bacterial kidney disease (BKD) in the fish challenged with the atypical growth, although small numbers of smooth colonies of R. salmoninarum were isolated from 8% of these fish. The atypical growth reported here may explain some of the failures of culture, when SKDM agar alone is used for the detection of BKD in subclinically infected fish.

Actinomycetales Infections↗
PubMed1995

Postantibiotic effect of ceftibuten on respiratory pathogens.

The postantibiotic effect (PAE) of ceftibuten, a novel beta-lactamase-stable cephem, was determined for Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. The ceftibuten PAE after a 2-hour exposure to 2 micrograms/ml (4 x minimum inhibitory concentration) for S. pyogenes was 2.7 to > 10 hours. The PAE for S. pneumoniae after a 2-hour exposure to 15 micrograms/ml, concentrations that are achieved in man after usual therapeutic doses, was 1.1 to 3.4 hours and the PAE for H. influenzae was 1 to 1.1 hours. M. catarrhalis had a PAE of 1.5 to 1.8 hours after exposure to 15 micrograms/ml of ceftibuten. The ceftibuten PAE was not affected by serum. The ceftibuten PAE was prolonged by exposure to a sub-minimum inhibitory concentration concentration of ceftibuten as would occur in the clinical situation. The PAE of ceftibuten was not affected by the copresence of erythromycin as would occur when treating infections in which atypical organisms are suspected. There was no correlation between bacterial reduction in colony-forming units and the duration of PAE. A level of 6 micrograms/ml of ceftibuten had a similar bacterial killing activity compared with a 6-hour exposure to 15 micrograms/ml of ceftibuten against S. pneumoniae, H. influenzae and M. catarrhalis. This study suggests that ceftibuten can be administered orally, once daily in an adult dose of 400 mg or a pediatric dose of 9 mg/kg, to treat respiratory infections caused by the most common pathogens.

Bacterial Infections↗
PubMed2006

Effect of marine bacterial isolates on the growth and morphology of axenic plantlets of the green alga Ulva linza.

The green marine macroalga, Ulva linza, adopts an "atypical" form when grown in the absence of bacteria. Twenty unique strains of periphytic bacteria, isolated from three species of Ulva, were identified by 16S rDNA sequencing. These isolates were assessed for their effect on the growth and morphological development of axenic plantlets of U. linza. Results showed that the effect of bacterial strains was strain- but not taxon-specific. Thirteen isolates returned the aberrant morphology to normal and of these, five also significantly increased growth rate. One isolate increased growth, but had no effect on morphology. Biofilms of some of these isolates stimulated the settlement of Ulva zoospores but there was no correlation between bacterial isolates that stimulated zoospore settlement and those that initiated changes in morphology and/or growth of the cultured alga.

Bacteria↗
PubMed2006

Case studies in current drug development: 'glycylcyclines'.

Glycylcyclines represent a new class of tetracycline antibiotics with potent antibacterial activities against resistant pathogens. One of the glycylcyclines, Tygacil, was selected for further development and has been approved by the FDA. It has an expanded broad-spectrum of antibacterial activity both in vitro and in vivo. It is active against a wide range of clinically relevant pathogens including Gram-positive, Gram-negative, atypical, and anaerobic bacteria and bacterial strains carrying either or both of the two major forms of tetracycline resistance (efflux and ribosomal protection). Most importantly, it is active against the multiply antibiotic resistant Gram-positive pathogenic bacteria, including methicillin-resistant Staphylococcus aureus (MRSA).

Bacteria↗
PubMed1985

Selective medium for the isolation and enumeration of Klebsiella spp.

A highly selective medium for the enumeration and isolation of Klebsiella pneumoniae and Klebsiella oxytoca was developed in which the typical colonies were convex and 1 to 2 mm in diameter. Their pigment was either a mucoid pink-red color or a more watery pale red with a dark red center. Relatively little colonial growth occurred for any other bacterial genera, and where such colonies did grow, they could be easily differentiated since the form was atypical. The medium already appears to have potential value as a means of assessing the efficiency of treating sewage and monitoring the microbiological quality of vegetables.

Bacteriological Techniques↗
PubMed1982

Kerion of the glabrous skin.

Five patients had kerion celsi on the glabrous skin. Four of these were farmers, and one was a veterinarian. The lesions occurred on the distal part of the forearm of four patients and in the breast area of one patient, most occurring during the spring months. Several of the lesions were misdiagnosed as bacterial infections or nondermatophytic fungal infections and were treated as such. Our report calls attention to this atypical form of localized inflammatory infection caused by tinea.

Adult↗
PubMed2004

[Persistent fever of unknown origin in two young infants caused by the atypical form of Kawasaki disease].

Two previously healthy infants, a boy and a girl aged 3 and 4 months, respectively, were admitted for fever of unknown origin with laboratory results indicating an inflammation. The boy presented with vomiting, pyuria, anaemia, and thrombocytosis. The girl presented with irritability, erythema and diarrhoea. All viral and bacterial cultures remained negative and supplementary radiology was unable to detect a focus of infection. The fever had persisted for at least 12 days in both cases before the diagnosis 'atypical Kawasaki disease' was considered. Cardiac echograms showed dilatation of the coronary arteries in both patients and confirmed the diagnosis. Immediate therapy with intravenous immunoglobulins and acetylsalicylic acid was given, whereupon the fever subsided within 24 hours; the further clinical course was uneventful. These cases illustrate the fact that atypical Kawasaki disease is often a late consideration, especially when the symptoms of the classical form are absent. This condition should be considered in every infant presenting with long-lasting unexplained fever.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Potential microbiological hazards in the production of refined paper products for food applications.

This study sought to investigate the significance of raw materials (starch-based glues, raw material papers) at different microbiologically critical stages in the manufacturing process of refined paper products. The study examined the occurrence of microorganisms in the process and in end-product samples. Microbiological surveys verified that the production and use of pasteurized starch-based glue was the most important factor threatening the process hygiene and product safety. Subsequently, the production and use of starch-based glue was changed, and a follow-up programme targeting the microbiological quality of glue was developed as part of a hygiene and safety management system. A total of 33 spore-forming bacterial and 15 enterobacterial isolates were ribotyped, and 22 and 10 different ribogroups (ribotypes), respectively, were generated. These isolates from starch-based glue, raw material paper and end products were atypical and, thus, in many cases physiological, chemotaxonomic (FAME) and molecular (partial 16S rDNA) results did not correspond. The most common spore-forming bacteria (55% of the isolates) were Paenibacillus sp. and within this genus several new species were also proposed. The most common enterobacteria (87%) were Enterobacter cloacae and Citrobacter freundii belonging to bacteria in hazard group 2, or species closely related to them. It was demonstrated that the same spore-forming bacteria (ribotypes) were present in both the glue samples and the end products (45% of isolates). All RiboPrint patterns were saved at the VTT identification library for future use.

Adhesives↗
PubMed1984

[Isolation of the L forms of Acinetobacter calcoaceticus var. Lwoffii in infectious endocarditis].

In the bacteriological study of blood samples taken from a patient with infectious endocarditis the hemoculture of the L-forms of A. calcoaceticus, var. lwoffii, was isolated. This hemoculture reverted into the bacterial form in the process of subculturing on solid media. The species of the isolated L-forms was established on the basis of the data obtained in the study of the biological properties of the revertants. To ensure the effectiveness of bacteriological investigations, a special search for atypical cultures is recommended in those cases when the inoculation of blood samples yields negative results.

Acinetobacter↗