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PubMed1976

Activity of four cephalosporin antibiotics in vitro against bovine udder pathogens and pathogenic bacteria isolated from newborn calves.

The in vitro activity of chephaloridine, cephalexin, cefatrizine (BL-S640), and cephapirin (BL-P-1322) was evaluated by the serial dilution method against pathogenic gram-positive and gram-negative bacteria isolated from bovine udders and neonatal calf diseases. Cephapirin showed the comparatively greatest activity against the most common streptococcal species associated with bovine mastitis, whereas cephaloridine exhibited the best activity against Staphylococcus aureus. Cefatrizine was more active than the other cephalosporins against the gram-negative bacteria studied. In general, the minimal bactericidal concentration of each cephalosporin was two- to fourfold lower than the comparative value reported in the literature against the same type of pathogen of human origin.

Animals↗
PubMed1990

The 96-kilodalton antigen as an integral membrane protein in pathogenic Entamoeba histolytica: potential differences in pathogenic and nonpathogenic isolates.

A surface antigen (EH-96) of Entamoeba histolytica was demonstrated to be a plasma membrane antigen by immunoprecipitation of metabolically 35S-labeled antigen from live trophozoites, Triton X-114 detergent extracts, and plasma membrane-enriched fractions prepared by concanavalin A membrane stabilization and differential centrifugation. In addition, the antigen was localized to the plasma membrane by electron microscopy with colloidal gold. Antigen from E. histolytica strains immunoprecipitated with specific immunoglobulin M (IgM) or IgG2b monoclonal antibody was identical by one-dimensional peptide mapping with N-chlorosuccinimide. Additionally, antigen from different axenically cultivated amebae was demonstrated to be identical by N-chlorosuccinimide peptide mapping, as were peptide maps of IgG and IgM monoclonal antibody-purified antigen. The 96-kilodalton (kDa) surface antigen was identified on four axenically cultivated pathogenic isolates and on three polyxenically cultivated pathogenic isolates (zymodeme II) of E. histolytica but was absent or present in lesser quantity on six nonpathogenic polyxenically cultivated isolates. The 96-kDa antigen was detected in liver abscess fluid from four patients with amebic abscesses by enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation. Two-dimensional gel electrophoresis profiles of the 96-kDa antigen purified from abscess material or from polyxenically cultivated trophozoites demonstrated that the antigens were related to the 96-kDa antigen found in axenically cultivated organisms.

Animals↗
PubMed1975

An experimentally pathogenic Bacillus species. II. The pathogenicity of the organism for mice.

The pathogenic effects produced in mice by intraperitoneal (i.p.) injection of a Bacillus species (OSU 372) are presented. This organism belongs to group 3 of the genus, and members of this group have not heretofore been shown to be pathogenic for mice even under experimental conditions. However, this organism is capable of producing a fatal involvement in doses which are not considered to be overwhelming. The mean lethal dose (LD50) of the organism for 20-25 g mice by the i.p. route is about 1 times 10-8 bacteria/mouse. A rapid drop in body temperature along with severe dehydration were noted in infected animals, and hematologic studies indicated that leukopenia and hemoconcentration also occurred. Although a transient septicemia developed, the bacteria could not be recovered from the tissues of fatally infected mice after a certain point in time. Results prevented indicate that the animals died of hypovolemic shock. A possible parallel with human bacillary infection is drawn.

Animals↗
PubMed1979

[Studies of the incidence of healthy carriers of "pathogenic strains" or potentially pathogenic strains in the hospital environment].

An investigation has been carried out on healthy carriers of "positive Staphylococcus coagulase" and "occasional pathogenic" strains among kitchen, canteen and dispensary staff in the IVth Geriatric Division and First Aid Clinic of the Bologna "M. Malpighi" Hospital. All stains of "positive Staphylococcus coagulase" and "occasional pathogens" considered (Pseudomonas aeruginosa and Citrobacter) were put through antibiotic and chemotherapeutic sensitivity tests. The results are reported in detail.

Anti-Bacterial Agents↗
PubMed1987

Pathogenic and non-pathogenic Naegleria and Acanthamoeba spp.: a new autochthonous isolate from an Italian thermal area.

We performed an epidemiological survey of 17 thermal baths and the same number of mud-basins. This study aimed to ascertain the presence and incidence of small free-living amoebae, particularly species and/or strains of Naegleria and Acanthamoeba spp., occasional etiological agents of fatal meningoencephalitis and/or ocular infections in man. Over 51 samples of water and mud incubated at 37 degrees C and at 45 degrees C, 34 (66.7%) became positive at 37 degrees C and 33 (64.7%) at 45 degrees C. We isolated 7 (6%) strains of Naegleria spp., 6 (5.2%) of Acanthamoeba spp., 39 (33.6%) of Vahlkampfia spp., 28 (24.1%) of Hartmannella spp. and 36 (31.1%) strains of other species of free-living amoebae. 4 strains of Naegleria spp. and 6 of Acanthamoeba spp. proved pathogenic both in vivo, after experimental infection (meningoencephalitis) in the albino mouse, and in vitro, having previously contaminated monolayers of Vero cell line (cytopathic effect). Within the isolated pathogenic strains of Naegleria spp., a new strain of N. australiensis s.sp. italica was typified from an immunochemical point of view. This should be added to previous isolations reported by us.

Amoeba↗
PubMed1978

[Aggravation of experimental dysentery in mice and acceleration of the process of multiplication of pathogenic and conditionally pathogenic bacteria under the effect of yeast RNA].

Simultaneous infection of mice with Sh. flexneri subtype 2a, culture, with various doses of RNA sodium salt (NaRNA) or administration of the preparation 3 hours prior to or 6, 12, and 18 hours after the infection was accompanied by aggravation of the experimental infection in mice. This was expressed in a greater number of animals which contracted the disease and died, and in increased blood and peritoneal exudate microbiol density. The same processes were noted in mice infected with equal doses of shigella cultures passaged four times through broth with NaRNA, in comparison with the animals infected with shigellae passaged through broth alone. Incubation of a number of pathogenic and conditionally pathogenic microbes in broth with NaRNA was accompanied by a significant increase in the bacterial biomass volume; at the same time other conditionally patoogenic microbes or even different strains of the same type of the microbes reacted to NaRNA but weakly. A possibility of realization of all of these processes in vivo and their influence on the origination of bacterial complications and development of the infection is supposed.

Animals↗
PubMed1992

Pathogenic activities of live cells and extracellular products of the fish pathogen Pasteurella piscicida.

The pathobiological activities in vivo and in vitro of live cells and extracellular products (ECP) of eleven Pasteurella piscicida strains of different origin were examined. Infectivity trials showed that P. piscicida did not possess strict host specificity since the majority of the isolates were virulent for gilthead seabream, rainbow trout and turbot, with LD50 values ranging between 10(3) and 10(6) live cells. However, none of the strains tested were pathogenic for mice (LD50 > 10(8) cells)). In addition, the ECP were strongly toxic for fish (LD50 ranging from 1.0 to 4.6 micrograms protein per g fish), which clearly demonstrates their important role in the pathogenesis of pasteurellosis. All the ECP samples were cytotoxic for fish and homoiothermic cell lines, possessed notable phospholipase activity and displayed haemolytic activity for sheep, salmon and turbot erythrocytes (but not for trout erythrocytes). However, the production of proteolytic enzymes differed among the P. piscicida strains. Although no strain displayed elastase activity, five isolates (the Japanese and Italian strains) hydrolysed casein and gelatin. All these biological activities in vivo and in vitro were lost after heat treatment (100 degrees C for 10 min). The general enzymic patterns of both live cells and ECP evaluated by the API-ZYM system also revealed some variation among the P. piscicida isolates. Generally, whole cells showed a wider range of enzymic activities than ECP. The results presented here are important for the selection of strains in the development of effective polyvalent pasteurellosis vaccines containing both whole cells and ECP.

Animals↗
PubMed1976

[Murine model for experimental studies on attenuated mutants of a Pasteurella multocida strain with pathogenicity for the calf. 1. Isolation and biological characterization of streptomycin-dependent mutants (Sm-d) and their examination for immunogenicity in comparison with thermally inactivated pathogens].

An experimental study was conducted into the immunisation of mice to a strain of Pasteurella multocida with pathogenicity for calf. Here are the results: (a) Stable Sm-d mutants were isolated. (b) The genetic stability of this mutant type was established by unsubstantiable reversion up to the magnitude of 10(-8) or - in cases in which 20 Sm-id revertants maximum occurred in 10(-8) Sm-d germs--by prolongation of the generation period of these suppressor mutants which can be defined also as minus mutants. (c) Stable attenuation of selected Sm-d mutants has been established in mice by intraperitoneal application of 108 germs. (d) Live germs with restricted reproduction exhibited more immunogenicity to thermally inactivated antigen.

Animals↗
PubMedDate not supplied

[Cultural, biochemical, cytochemical, pathogenic and morphological aspects (as seen with the scanning microscope) of pathogenic strains of Candida albicans treated with pyrrolnitrin].

The author has analyzed the pyrrolnitrine activity on eighty strains of Candida albicans isolated from hospital patients. On these various strains the M.I.C., the enzymatic activity, the pathogenicity on rabbits, the ability to form clamydospores were determined. Also cytochemical tests, tests on chorioallantoic membrane, absorption tests and morphological analysis at the scanning microscope were performed on these strains. The various findings obtained have shown a strong activity of pyrrolnitrine on the different biological activities of Candida albicans strains used in the present work.

Antifungal Agents↗
PubMed1979

Electrophoretic isoenzyme patterns of the pathogenic and non-pathogenic intestinal amoebae of man.

Cultured stocks of Entamoeba hartmanni, Endolimax nana, Iodamoeba buetschlli and Dientamoeba fragilis were compared with the four Entamoeba histolytical groups already described (SARGEAUNT et al., 1978), by the electrophoretic patterns of three enzymes: glucose phosphate isomerase (GPI), phosphoglucomutase (PGM) and L-malate: NADP+ oxidoreductase (oxalacetate-decarboxylating) (ME). All the species were easily distinguished by their characteristic patterns.

Amoeba↗
PubMed1989

Incidence of hemagglutination activity among pathogenic and non-pathogenic Bacteroides fragilis strains and role of capsule and pili in HA and adherence.

We analyzed the ability of 120 encapsulated strains of B. fragilis to agglutinate guinea pig and human red blood cells. Sixteen strains showed a strong hemagglutination (HA) ability, 21 strains a moderate HA ability, 7 strains a weak HA ability and 74 strains did not agglutinate the tested red blood cells. Six strains tested from each HA group were able to adhere to cheek epithelial cells and to a cultured human intestinal cell line. Hemagglutinating strains were the most adhesive. By electron microscopy, pilus-like structures were found in three of the encapsulated adhesive strains. Treatment of the bacterial cells with pronase E reduced both HA ability and adherence of piliated encapsulated, and of piliated non-encapsulated strains. Glucosidase treatment of cells reduced HA activity and adherence of piliated encapsulated and of non-piliated encapsulated strains. Finally, it was found that hemagglutinating strains are more frequently isolated from clinical specimens (55%) than from feces of healthy donors (20%).

Bacterial Adhesion↗
PubMed1988

Immunological differentiation of pathogenic and non-pathogenic isolates of Entamoeba histolytica.

Entamoeba histolytica can act as a harmless commensal organism in the lumen of the large intestine, or can cause invasive amoebiasis. Some workers have suggested that there are two distinct subspecies of this organism, and that only one of these is associated with invasive disease. Present isoenzyme tests to identify the subspecies take several days to analyse: we report a technique that uses immunofluorescence with monoclonal antibodies, takes two days to perform, and may, therefore, assist in the clinical management of patients infected with this organism.

Animals↗
PubMed1992

Molecular clones from a non-acutely pathogenic derivative of SIVsmmPBj14: characterization and comparison to acutely pathogenic clones.

Molecularly cloned simian immunodeficiency viruses capable of inducing acute, fatal disease in pig-tailed macaques had been derived previously from a biological clone (bcl-3) of the PBj14 isolate of SIV from sooty mangabey monkeys (SIVsmmPBj14). The present study was undertaken in order to characterize virus from a second biological clone of SIVsmmPBj14, bcl-1, which fails to induce acute or fatal disease. Polymerase chain reaction was used to amplify 5' and 3' viral genome halves. The DNA sequence of two 3' halves was determined, and an infectious recombinant generated using a bcl-3-derived 5' half and a bcl-1-derived 3' half. Overall, bcl-1- and bcl-3-derived viruses displayed close homology, differing by a total of 2% at the DNA level and 1-6% at the amino acid level within the 8 open reading frames examined. In contrast to the bcl-3-derived viruses, the bcl-1-derived viruses encode a truncated transmembrane envelope glycoprotein. Another consistent difference was the presence of a 22 bp duplication in the U3 portion of the long terminal repeat (LTR) of bcl-3-derived viruses that includes the NF-kappa B transcriptional enhancer binding site. To assess the importance of this duplication, virus chimeras were generated which removed the duplication from the 3'-LTR or from both LTRs of a bcl-3 clone. The former virus was unstable, reacquiring the duplication through recombination with the 5' LTR. No consistent difference were observed, however, between viruses with or without the duplication in the in vitro studies conducted to date.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗