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PubMed1990

Fate of pathogenic and non-pathogenic Escherichia coli strains in two fermented milk products.

The growth and survival of pathogenic and non-pathogenic strains of Escherichia coli was determined in traditionally fermented pasteurized and unpasteurized milk and in Lacto, an industrially fermented milk. Each milk treatment was incubated at 20 degrees C for 24 h and then stored at either 20 degrees C or 5 degrees C for 96 h. Lacto inhibited all the three E. coli strains. Two strains could not be recovered and the third survived only in very low numbers after 24 h storage of Lacto at both 20 degrees C and 5 degrees C. All three E. coli strains survived and multiplied to maximum cell numbers in the range 10(7)-10(9)/ml during traditional fermentation of unpasteurized milk. Cell numbers decreased to 10(3)-10(6) and 10(2)-10(5) during storage of the fermented product at 20 degrees C and 5 degrees C respectively. Higher maximum numbers, 10(9)-10(10), of the three strains of E. coli were attained during traditional fermentation of pasteurized milk. The numbers decreased to 10(5)-10(8) and 10(4)-10(7) during storage of the fermented product at 20 degrees C and 5 degrees C respectively. Generally, fewer E. coli survived when the fermented milk products were stored at refrigeration temperature.

Animals↗
PubMed1977

Pathogenic mycoplasmas: cultivation and vertebrate pathogenicity of a new spiroplasma.

A spiroplasma recovered from allantoic fluids of chick embryos infected with the tick-derived suckling mouse cataract agent was grown in continuous passage on a new artificial culture medium. The cultured organisms induced typical ocular and other disease symptoms in susceptible animals, and were reisolated from involved host tissues. Although spiroplasmas have been previously recognized as plant and insect pathogens, this is the first spiroplasma shown to multiply at 37 degrees C and to be pathogenic for vertebrates.

Animals↗
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↗
PubMed1993

Repeats in an extracellular protein of weakly pathogenic strains of Streptococcus suis type 2 are absent in pathogenic strains.

Streptococcus suis type 2 strains that are pathogenic for pigs produce a 110-kDa extracellular protein factor (EF). Nonpathogenic and weakly pathogenic strains do not produce EF or produce a protein (EF*) that is immunologically related to EF. To study the pathogenesis of S. suis type 2 in pigs and to develop tools and methods for the control of S. suis type 2 infections, we cloned and characterized the genes encoding EF and various EF* proteins. Analysis of the deduced amino acid sequences showed that the first 833 amino acids at the N terminus of the EF and EF* proteins were nearly identical. The proteins differed, however, at their C termini. Unlike the 110-kDa EF protein, the EF* proteins contained several repeated units of 76 amino acids. The number and arrangement of the repeats in the EF* proteins varied. The data suggest that the gene encoding EF could have evolved from an epf* gene by a specific deletion event. The lack of repeated amino acid units in the EF protein may be related to virulence.

Amino Acid Sequence↗
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↗
PubMedDate not supplied

Isoenzyme patterns of pathogenic and non-pathogenic Naegleria spp. using agarose isoelectric focusing.

Using agarose isoelectric focusing, the isoenzyme patterns of 7 different enzymes were compared in 52 Naegleria strains. The pathogenic N. fowleri was found the most homogeneous species. N. lovaniensis seems to be constituted of different types which form nevertheless a cohesive group. Within N. gruberi, large interstrain band variations were found in almost all enzyme systems. A re-examination of the taxonomic position of this species may therefore be taken into consideration. High temperature strains from Australia were confirmed to be different from N. lovaniensis. Members of a new pathogenic Naegleria sp., N. australiensis, seem to occur in Europe. Large thermophilic strains with many large pores in the cysts show identical zymograms and may constitute a new species or genus.

Acid Phosphatase↗
PubMedDate not supplied

[Value of antigen, antibody and pathogen-specific lymphocyte detection in diagnosis of pathogen-induced arthritis].

In the differential diagnosis of infection-related arthritis (infectious arthritis, viral arthritis, reactive arthritis or Reiter's syndrome, Lyme disease) various laboratory methods are applied for the detection of the inciting antigen, specific antibodies or microbe-specific T-lymphocytes. In infectious (septic) bacterial or fungal arthritis, the definitive diagnosis can be made only by recovering the organism from the synovial fluid or membrane. Also, in reactive arthritis following extraarticular infection with Yersinia, Salmonella, Shigella, Campylobacter, or Chlamydia, one of the major shifts in perception of disease pathogenesis has been the detection of bacterial determinants by immunological methods and polymerase chain reaction (PCR) actually within the joint. In sexually acquired reactive arthritis, the etiologic diagnosis should be based on the direct detection of the pathogen (mainly C. trachomatis) from the urogenital smear specimen. For clinical routine, serological tests for bacteria specific antibodies (IgM and IgA class) are often necessary to show recent or persistent infection with the triggering pathogen. However, a cautionary note regarding the diagnostic significance of antibacterial antibody profiles has been sounded in several studies because of the high prevalence of bacteria-specific antibodies in the healthy population. The same problem may arise in the interpretation of virus-specific antibodies in the differential diagnosis of acute polyarthritis. Antigen-specific proliferation of synovial fluid lymphocytes can confirm the clinical diagnosis in patients with reactive arthritis and Lyme disease, although unspecific proliferation to several bacteria can also be observed in reactive arthritis as well as in many other arthritis.

Antibodies↗
PubMed1994

Studies on the bacterial flora of fish which are potential pathogens for human. Isolation of various potential human pathogenic organisms from different parts of fish and their significance in initiating human diseases.

Freshwater fish of different categories, collected from market of Dhaka City of Bangladesh, were studied for the bacterial flora. Potential human pathogens were isolated from about eighty-five percent of the fish studied. Organisms isolated were Aeromonas spp., (69.2%), Vibrio spp., (42.3%), Plesiomonas shigelloides (35.9%) and Escherichia coli (16.7%). The high association of potential human pathogens among the freshwater fish suggest that if fish are handled improperly or if consumed undercooked or uncooked may cause various diseases to susceptible individual.

Animals↗
PubMed1984

The pathogenicity of Salmonella mbandaka in specific pathogen free rabbits.

Salmonella mbandaka was isolated from the lungs of three rabbits that developed a peracute disease and died three to eight weeks following extensive experimental manipulation. To examine the pathogenicity of this rare serotype, clinically normal, S. mbandaka-carrier rabbits were subjected to either corticosteroid immunosuppression alone or corticosteroid immunosuppression with a minor surgical procedure. Acute or peracute salmonellosis developed in one of two rabbits immunosuppressed only, and in three of four rabbits immunosuppressed and surgically manipulated. Stressful experimental procedures may precipitate episodes of clinical salmonellosis in rabbits harboring this organism. Salmonella mbandaka, should be considered a zoonotic agent in the laboratory environment.

Animals↗
PubMed1993

Distribution of a lipooligosaccharide-specific sialyltransferase in pathogenic and non-pathogenic Neisseria.

Sialyltransferase activity has been detected in Triton X100 extracts of all examined strains of pathogenic Neisseria as well as in 17 out of 18 Neisseria lactamica isolates. The enzyme was detected both in strains able to synthesize the 4.5 kDa lipooligosaccharide (LOS) component known to be sialylated in vivo and in vitro by cytidine 5'-monophospho-N-acetylneuraminic acid, and in some strains which lack this component. Exogenous 4.5 kDa+ LOS was required to detect the sialyltransferase activity in strains which lacked the LOS component. Sialyltransferase activity in a serogroup A, L11 (4.5 kDa-) meningococcal strain sialylated exogenous purified LOS from gonococci. The meningococcal serogroup B and C strain sialyltransferases active with LOS acceptors appeared to be distinct from the sialyltransferase required for the synthesis of the meningococcal polysialic acid capsule.

Lipopolysaccharides↗
PubMedDate not supplied

Antimicrobial activity of cefotaxime tested against infrequently isolated pathogenic species (unusual pathogens).

The cefotaxime sodium spectrum of activity is very broad and includes many common species and a variety of less frequently isolated pathogens. We have reviewed the clinical microbiology literature (44 references) and the data base of the University of Iowa Hospitals and Clinics (Iowa City, IA) to collect data on the activity of cefotaxime against the less common species. Cefotaxime was consistently active against Actinobacillus actinomycetemcomitans, Capnocytophaga spp., Eikenella corrodens, Erysipelothrix rhusiopathiae, Pasteurella multocida, Plesiomonas shigelloides, and Fusobacterium nucleatum. The species Alcaligenes xylosoxidans, Flavobacterium spp., Stenotrophomonas (Xanthomonas) maltophilia, Bacillus cereus, Listeria monocytogenes, and Rhodococcus equi were uniformly cefotaxime resistant. For many other species there was considerable variation in reported minimum inhibitory concentrations. These data may be helpful in guiding therapy of unusual infections, particularly in the case of fastidious species, where the appropriate susceptibility testing methodology may not be immediately or routinely available.

Bacteria, Anaerobic↗
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↗