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At least 73 records · Page 4Linked to original sources
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↗
PubMed1995

[A nation-wide surveillance of pathogen in elderly patients with urinary tract infections. 1st Report: Distribution of pathogen].

A nation-wide surveillance of causative organisms was conducted on 1,699 elderly patients with UTIs aged more than 65 in 190 private clinics and 73 hospitals in August and September, 1993, in order to investigate the distribution of causative bacteria and the relationship between isolates and the background of those patients. From 1,233 of the 1699 patients, 1,636 strains were isolated. E. coli was isolated most frequently (30%). in male and older patients, less E. coli were isolated, while more attenuated Gram negative rods such as NFGNR including P. aeruginosa were found. A similar trend was observed in uncomplicated UTIs isolates in this study. More E. coli were isolated from patients with stronger subjective symptoms while more bacteria other than E. coli were isolated in those with weaker subjective symptoms. From the above findings, it was confirmed that a high recovery rate of opportunistic pathogen which is less susceptible to various antibacterials is one the refractory factors in elderly patients with UTIs. Therefore, it is necessary to select a suitable antibacterial that can be used for complicated UTIs in elderly patients even when diagnosed as uncomplicated UTIs. Regardless of the size of the clinic or hospital, when treating elderly patients, with unsatisfactory results in initial treatment and with less subjective symptoms the physician must bear this in mind.

Aged↗
PubMed1995

[A nation-wide surveillance of pathogen in elderly patients with urinary tract infections. 2nd Report: Sensitivities of pathogen for oral antibacterial agents].

A nation-wide surveillance of sensitivities of bacteria, which were isolated from elderly patients with UTIs aged more than 65 in 190 private clinics and 73 hospitals, for oral antibacterials, CPFX, OFLX, NFLX, CPDX and CCL, was conducted in August and September in 1993. Antibacterial activities of 5 agents against all 1,511 strains were intensified in CPFX, OFLX, NFLX, CPDX and CCL in that order. Major pathogens such as Enterobacteriaceae, E. faecalis, Staphylococcus spp. and P. aeruginosa were more susceptible to fluoroquinolones than cephems. The rate of resistant strains to antibacterials was higher in isolates from older patients, patients with complicated UTIs and with indwelling catheter. The representative of resistant strains was P. aeruginosa, and about 50% of the strains of P. aeruginosa were resistant to even CPFX which had the most superior antibacterial activity among the 5 agents. About 40% of the S. aureus were MRSA, which were almost resistant to the 5 agents. From the above findings, it was confirmed that a high recovery rate of strains which is less susceptible to various antibacterials is one of the refractory factors in elderly patients with UTIs, particularly in complicated UTIs and with indwelling catheter. Regardless of the size of the clinic or hospital, Fluoroquinolones are more suitable for the treatment of elderly patients with UTIs than cephems.

Aged↗
PubMed1994

Excision of large DNA regions termed pathogenicity islands from tRNA-specific loci in the chromosome of an Escherichia coli wild-type pathogen.

Uropathogenic Escherichia coli 536 (O6:K15:H31) carries two unstable DNA regions, which were shown to be responsible for virulence. These regions, on which the genes for hemolysin production (hly) and P-related fimbriae (prf) are located, are termed pathogenicity islands (PAI) I and II, and were mapped to positions 82 and 97, respectively, on the E. coli K-12 linkage map. Sequence analysis of the PAI region junction sites revealed sequences of the leuX and selC loci specific for leucine and selenocysteine tRNAs. The tRNA loci function as the targets for excision events. Northern (RNA) blot analysis revealed that the sites of excision are transcriptionally active in the wild-type strain and that no tRNA-specific transcripts were found in the deletion mutant. The analysis of deletion mutants revealed that the excision of these regions is specific and involves direct repeats of 16 and 18 nucleotides, respectively, on both sides of the deletions. By using DNA long-range mapping techniques, the size of PAI I, located at position 82, was calculated to be 70 kb, while PAI II, mapped at position 97, comprises 190 kb. The excision events described here reflect the dynamics of the E. coli chromosome.

Base Sequence↗
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↗
PubMed1995

Pathogenicity of human and porcine intestinal spirochetes in one-day-old specific-pathogen-free chicks: an animal model of intestinal spirochetosis.

One-day-old chicks were infected orally with two strains of weakly hemolytic spirochetes isolated from a human and a pig with intestinal spirochetosis. These spirochetosis both colonized birds, attached end-on to their cecal enterocytes, induced watery diarrhea, and significantly depressed growth rates. Cultures of Serpulina innocens failed to colonize the chicks.

Animals↗