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PubMed2002

Analysis of the 16S-23S rDNA intergenic spacers (IGSs) of marine vibrios for species-specific signature DNA sequences.

Vibrios are widespread in the marine environment and a few pathogenic species are known to be commonly associated with outbreaks of diarrheal diseases in humans due to the consumption of raw or improperly cooked seafood. However, there are also many Vibrio species which are potentially pathogenic to vertebrate and invertebrate aquatic animals, and of which little is known. In an attempt to develop rapid PCR detection methods for these latter class of vibrios, we have examined the 16S-23S intergenic spacers (IGSs) of 10 lesser-known Vibrio species and successfully developed species-specific primers for eight of them--Vibrio costicola, V. diazotrophicus, V. fluvialis, V. nigripulchritudo, V. proteolyticus, V. salmonicida, V. splendidus and V. tubiashii. The IGS amplicons were amplified using primers complementary to conserved regions of the 16S and 23S rRNA genes, and cloned into plasmid vectors and sequenced. Analysis of the IGS sequences showed that 37 ribosomal RNA (rrn) operons representing seven different IGS types have been cloned from the 10 vibrios. The three IGS types--IGS(0), IGS(IA) and IGS(Glu)--were the most prevalent forms detected. Multiple alignment of representative sequences of these three IGS types from different Vibrio species revealed several domains of high sequence variability, which were used to design species-specific primers for PCR. The specificity of the primers were evaluated using total DNA prepared from different Vibrio species and bacterial genera. The results showed that the PCR method can be used to reliably detect eight of the 10 Vibrio species in marine waters in this study.

Base Sequence↗
PubMed2004

The value of a CT-guided fine needle aspirate in infants with lung abscess.

OBJECTIVE: To describe the range of pathogens isolated from a lung abscess in infants less than one year of age. To assess the role of direct culture from the abscess. METHODS: The two index cases were managed in 2002. An institution-based review was conducted of all infants up to one year of age diagnosed with a lung abscess between 1989 and 2002. Data sources were hospital's disease index and Neonatal Intensive Care Unit Audit database using ICD9 and ICD10 diagnostic codes for 'lung abscess'. RESULTS: Five infants, under the age of one year, were treated for a lung abscess. In the one case where the abscess was left-sided it was associated with a congenital cystic adenomatoid malformation of the lung. Pathogens were isolated following direct culture of the abscess in four cases. In three cases a single pathogen was isolated: pseudomonas aeruginosa, staphylococcus aureus and haemophilus influenzae. In one case a mixture of escherichia coli, streptococcus milleri and an anaerobe, propionibacteria, were cultured. Antibiotic therapy was directed at the identified pathogen(s) in all four cases. There was no mortality or recurrence. CONCLUSION: Predisposing factors for a lung abscess in infancy include prematurity, assisted ventilation, congenital lung anomaly and aspiration. Given the range of potential pathogens, direct culture by CT-guided fine needle aspiration is recommended to direct appropriate intravenous medical therapy provided the abscess is located peripherally.

Anti-Bacterial Agents↗
PubMed2004

Extracellular virulence factors of group B Streptococci.

Group B Streptococcus (GBS) is the leading cause of severe bacterial infections in human newborn infants. Advances in streptococcal molecular genetics and refinement of in vitro and in vivo model systems of GBS disease have led to the discovery and characterization of several extracellular virulence factors elaborated by this pathogen. This review summarizes our current understanding of GBS extracellular virulence factors including the beta-hemolysin/cytolysin, C5a-peptidase, hyaluronate lyase, CAMP factor, oligopeptidase, and carbohydrate exotoxin CM101. The molecular basis and potential pathogenic role(s) of each factor are considered in the context of neonatal infection.

Humans↗
PubMed2000

Gastrointestinal tract as a part of immune defence.

The paper is devoted to reviewing the function of gastrointestinal mucosal immune system. Gut-associated lymphoid tissue (GALT) provides the host with protective mechanisms against invasion by potential pathogens across the mucosal surface, and on the other hand, it plays a role in the development of induced tolerance against harmless products of digestion and the normal intestinal flora, all of which are potentially immunogenic. First the organization of GALT, its afferent and efferent limbs are described, then the normal B cell homeostasis and finally the induced oral tolerance are discussed. Knowledge of mechanisms of mucosal immune response is essential to complete understanding of the pathogenesis and treatment of inflammatory gastrointestinal diseases as well.

Digestive System↗
PubMed1979

Pathogenicity of the subspecies mycoides of Mycoplasma mycoides for cattle, sheep and goats.

Recent work has shown that strains classified as M. mycoides subsp. mycoides may be separated into 2 types according to their growth rate and their behaviour in certain biochemical tests. The large colony (LC) types, most of which are from goats, are pathogenic for sheep and goats but apparently not for cattle. The small colony (SC) types include the classical contagious bovine pleuropneumonia (CBPP) strains from cattle and four strains from goats. These SC types are potentially pathogenic for cattle, sheep and goats. Strains of M. mycoides subsp. mycoides from CBPP differ in their virulence in cattle. The degree of virulence is correlated with the quantity of galactan produced in cultures of the organism, suggesting an important role for galactan in pathogenicity. This is consistent with the production by galactan of physiological effects in calves and in the enhancement of infection in cattle given galactan at the same time as cultures of the organism. Contagious caprine pleuropneumonia (CCPP) can be produced experimentally in goats using cultures of M. mycoides subsp. capri. Whether the glucan produced in such cultures is a factor in pathogenicity of this organism has not been determined. Hydrogen peroxide demonstrated in tracheal organ cultures of M. mycoides subsp. capri may contribute to its pathogenicity.

Animals↗
PubMed1983

[Infections in patients with gynecologic malignancies].

Infections in patients with gynecologic malignancies occur frequently and are the cause of death in 50 to 60% of the cases. The patient with cancer is a compromised host with an increased susceptibility to infection due to the malignancy itself on the one hand and due to therapeutic-modalities, like extensive surgical procedures, radiation- and cytotoxic chemotherapy on the other hand. Aetiologically these infections are mostly due to a disruption of anatomic structures which normally prevent the invasion of exogenous or endogenous microorganisms, or to obstructive processes or to tumour necrosis. Septicaemia can result from propagation of such a localized infection beyond the site of the tumour. The causative pathogens infecting the compromised host are mostly members of the indigenous microbial flora of the genital tract, which is influenced by surgery, irradiation and chemotherapy. Postoperatively in the vaginal vault the number of most potentially pathogenic aerobic and anaerobic bacterial species is higher, polymicrobial mixed infections are frequent. Neither the intracavitary radiation-therapy with Radium or Iridium-192 (afterloading) nor the external high-voltage therapy decrease the number of pathogenic bacterial species in the uterus and in the vagina of patients with cervical or endometrial cancer. The symptoms of infection in cancer patients can be "masked". Fever in patients with genital malignancies is mostly due to local infections and influences the prognosis negatively. The 5-year survival rate of irradiated patients with fever is significantly lower. Infections following radical hysterectomy, irradiation and/or cytotoxic chemotherapy like pelvic abscesses, peritonitis, pneumonia and septicaemia can be fatal. Urinary-tract-, wound- and vaginal vault-infections occur frequently, but are rarely severe. Therapeutically in severe infections a combination antibiotic therapy, which is effective against most pathogenic members of the genital flora, is required. Short courses of perioperative prophylactic antibiotics are useful both in radical hysterectomy and with intracavitary irradiation.

Anti-Bacterial Agents↗
PubMed1982

[Additional studies of the pathogenicity of aerobic spore-forming organisms (genus Bacillus) for mice].

An investigation of the parenteral pathogenic potential of aerobic spore-forming bacteria (genus Bacillus) in mice revealed that in the case of i.p. inoculation (0.5 ml suspension, 10(6)-10(7) viable cells per ml) only B. cereus was pathogenic, killing appr. one half of the inoculated animals (293 out of 577). Other bacilli (B. subtilis, B. megaterium, B. pumilus etc.) administered intraperitoneally did not produce any lethal effect. If inoculated intracerebrally, B. cereus killed appr. 90% of the mice (138 out of 155), while for other bacilli the rate was appr. 50% only (260 out of 529). It is suggested that most of the aerobic spore-forming organisms cultured from cases of hospital infections are B. cereus which, however, does not completely exclude the presence of other species.

Animals↗
PubMed1984

Incidence of pathogenic bacteria from mesenteric lymph nodes and ileal serosa during Crohn's disease surgery.

Samples of ileal serosa and mesenteric lymph nodes have been harvested before antibiotic administration during 46 non-contaminated operations for Crohn's disease and compared with 43 operations for conditions other than Crohn's. Potentially pathogenic bacteria were isolated from the serosa in 12 (27 per cent) Crohn's patients, compared with 6 (15 per cent) controls (P = 0.04). Intestinal bacteria were recovered from mesenteric nodes in 15 (33 per cent) Crohn's patients compared with 2 (5 per cent) controls (P = 0.006). These findings suggest that bacteria leak from the small bowel lumen in a high proportion of Crohn's disease patients. This may explain the pathogenesis of abscess and fistula in this disorder as well as the high rate of sepsis following elective surgery even in the absence of macroscopic contamination.

Abdomen↗
PubMed1984

Teratogenicity of Australian Simbu serogroup and some other Bunyaviridae viruses: the embryonated chicken egg as a model.

The use of embryonated chicken eggs as a model for assessing the teratogenic potential of animal viruses was investigated with 12 members of the Bunyaviridae family. Infection of 4-day-old embryonated chicken eggs via the yolk sac with 10 of the viruses resulted in deaths or congenital deformities that were similar to those observed in Akabane virus infections of fetal ruminants and included arthrogryposis, scoliosis, mandible defects, and retarded development. Statistical analysis showed that the viruses fell into three main groupings, namely, those that caused both death and deformities (Akabane, Aino, Tinaroo, and Belmont viruses), those that mainly caused death (Peaton, Thimiri, and Facey's Paddock viruses), and those that required very high doses to cause either death or deformities (Douglas and CSIR0296 viruses). In addition, two viruses (Kowanyama and Mapputta viruses) caused neither death nor deformities. A difference in the pathogenic potential between two Akabane isolates (B8935 and CSIR016) in the embryonated chicken egg model was found to correlate with differences previously observed in experimentally infected sheep; Akabane CSIR016 was the more pathogenic. It is concluded that the embryonated chicken egg model should also be of value in assessing the teratogenic potential of other Bunyaviridae and attenuated vaccine viruses, although it does not assess the ability of the virus to cross the placenta.

Animals↗
PubMed1999

The microbiology of infected and noninfected leg ulcers.

BACKGROUND: A clinical study was undertaken to investigate and compare specifically the aerobic and anaerobic microbiology of infected and noninfected leg ulcers. METHODS: Leg ulcers, defined as being infected on the basis of clinical signs, were swab sampled and investigated for aerobic and anaerobic microorganisms using stringent isolation and identification techniques. RESULTS: Two hundred and twenty isolates were cultured from 44 infected leg ulcers, in comparison with 110 isolates from 30 noninfected leg ulcers. Statistical analysis indicated a significantly greater mean number of anaerobic bacteria per infected ulcer (particularly Peptostreptococcus spp. and Prevotella spp.) in comparison with the noninfected ulcer group (2.5 vs. 1.3, respectively) (P < 0.05). Also, anaerobes represented 49% of the total microbial composition in infected leg ulcers compared with 36% in noninfected leg ulcers. The mean numbers of aerobes per wound in the two ulcer groups were not statistically different (P > 0.05). The study failed to demonstrate a clear correlation between commonly implicated facultative pathogens and wound infection. The isolation rate of Pseudomonas aeruginosa was generally low and, although Staphylococcus aureus was a frequent isolate in both wound types, it was more prevalent in noninfected leg ulcers. CONCLUSIONS: This study has demonstrated the complex aerobic-anaerobic microflora which exists in leg ulcers, the prevalence of anaerobes in infected wounds, and a poor correlation between the presence of specific aerobic pathogens and wound infection. In view of these findings, the role of microbial synergistic interactions in the pathogenesis of chronic wound infection may be of greater clinical importance than the isolated involvement of any specific potential pathogen.

Anti-Bacterial Agents↗
PubMed1997

Light chain usage in anti-double-stranded DNA B cell subsets: role in cell fate determination.

Two major mechanisms for the regulation of autoreactive B cells that arise in the bone marrow are functional silencing (anergy) and deletion. Studies to date suggest that low avidity interactions between B cells and autoantigen lead to B cell silencing, whereas high avidity interactions lead to deletion. Anti-double stranded (ds) DNA antibodies represent a pathogenic autospecificity in Systemic Lupus Erythematosus (SLE). An understanding of their regulation is critical to an understanding of SLE. We now demonstrate in a transgenic model in which mice express the heavy chain of a potentially pathogenic anti-DNA antibody that antibody affinity for dsDNA does not alone determine the fate of anti-dsDNA B cells. B cells making antibodies with similar affinities for dsDNA are regulated differently, depending on light chain usage. A major implication of this observation is that dsDNA may not be the self antigen responsible for cell fate determinations of anti-dsDNA B cells. Light chain usage may determine antigenic cross-reactivity, and cross-reactive antigens may regulate B cells that also bind dsDNA.

Amino Acid Sequence↗
PubMed2006

Human antibodies induce arthritis in mice deficient in the low-affinity inhibitory IgG receptor Fc gamma RIIB.

Rheumatoid arthritis (RA) is a complex autoimmune disease with a poorly understood pathogenesis. The disease is associated with polyclonal B cell activation and the production of autoantibodies (autoAbs), but there is a longstanding controversy as to whether such Abs contribute to, or are secondary to, the pathogenesis of RA. To address the potential pathogenicity of human RA-associated Abs, we developed a passive transfer model involving mice deficient in the low-affinity inhibitory Fc receptor, FcgammaRIIB. We report that plasma or serum from patients with active RA can induce inflammation and histological lesions in FcgammaRIIB-/- mice consistent with arthritis, and that this pathogenic activity is caused by the immunoglobulin G-rich fraction. Our results suggest that humoral autoimmunity can contribute directly to autoimmune arthritis, and that FcgammaRIIB-/- mice are a promising model to evaluate the arthritogenic potential of human autoAbs.

Animals↗
PubMed2004

Advanced glycation: how are we progressing to combat this web of sugar anomalies in diabetic nephropathy.

Advanced glycation end products (AGEs) in diabetic nephropathy have been extensively researched over the last decade and are now firmly established as major players in this disease. The enigma remains the search for the ideal AGE inhibition therapy, which is a great challenge in the context of the structural diversity inherent to AGE chemistry. Certainly, there is a requirement to standardize measurements of circulating and tissue levels of AGEs and to characterize the pathogenic potential of specific AGE moieties. In order to develop more effective, targeted approaches to combat diabetic nephropathy, the mechanisms of action of selective AGE inhibitors and the inter-relationships of advanced glycation with other pathogenic pathways must be addressed.

Animals↗
PubMed2002

Oligoalginate recognition and oxidative burst play a key role in natural and induced resistance of sporophytes of laminariales.

Forty-five species of brown algae (Phaeophyceae) were surveyed for their capacity to respond by an oxidative burst to challenges with alginate oligosaccharides. Intertidal frondose brown algae (Fucales) constitutively released high quantities of peroxide. The capacity to recognize oligoguluronates and to react with an oxidative burst was confined to alginate-rich taxa with complex thallus morphology, epitomized by the sporophytes of Laminariales. When kelp sporophytes were impaired in their capacity to perform an oxidative burst by the NAD(P)H oxidase inhibitor diphenylene iodonium, they were readily degraded by their bacterial epiflora. Thus, in these algae, the oxidative response is an essential element of natural resistance. We also report on the establishment of a well-defined experimental system for investigations on kelp immunity, with Laminaria digitata as the host and its phaeophycean endophyte, Laminariocolax tomentosoides, as the pathogen. We found that an alginate-triggered oxidative burst significantly induces resistance in Laminaria digitata against infection. From these findings we infer that oligoalginate signals are important cues in the interaction between laminarialean kelps and potential pathogens.

Adaptation, Physiological↗
PubMed1999

Predisposing factors to bacterial colonization in chronic obstructive pulmonary disease.

The aim of this prospective observational study was to determine those factors influencing bacterial colonization in patients with stable chronic obstructive pulmonary disease (COPD). Eighty-eight outpatients with stable COPD and 20 patients with normal spirometry and chest radiography (controls) had a fibreoptic bronchoscopy performed with topical aerosol anaesthesia. Bacterial colonization was determined using the protected specimen brush (PSB) with a cut-off > or = 10(3) colony-forming units (CFU x mL(-1)). The influence of age, degree of airflow obstruction, smoking habit, pack-yrs of smoking, and chest radiographic findings on bacterial colonization were assessed by univariate and multivariate analysis. Significant bacterial growth was found in 40% of patients and in none of the controls. Haemophilus influenzae, Streptococcus viridans, S. pneumoniae and Moraxella catarrhalis were the most frequent pathogens. After adjustment for other variables, severe airflow limitation (odds ratio (OR) 5.11, 95% confidence interval (CI) 1.45-17.9) and current smoking (OR 3.17, 95% CI 2.5-8) remained associated with positive bacterial cultures. When only potentially pathogenic micro-organisms were considered, significant bacterial growth was found in 30.7% of patients, with severe airflow obstruction (OR 9.28, 95% CI 2.19-39.3) being the only variable independently associated with positive bacterial cultures. Our results show that stable chronic obstructive pulmonary disease patients have a high prevalence of bacterial colonization of distal airways which is mainly related to the degree of airflow obstruction and cigarette smoking.

Aged↗
PubMed2000

Development of a direct viable count procedure for the investigation of VBNC state in Listeria monocytogenes.

A viable but non-culturable (VBNC) bacterial state was originally detected in studies in environmental microbiology. In particular, this state has been demonstrated for a number of human pathogens (Escherichia coli, Salmonella enteritidis, Vibrio cholerae, Legionella pneumophila and Campylobacter jejuni). The presence of VBNC cells poses a major public health problem since they cannot be detected by traditional culturing methods and the cells remain potentially pathogenic under favourable conditions. But, as far as we know, the VBNC state has not been yet described in Listeria monocytogenes. In most studies, this has been assessed by the Kogure procedure based on cellular elongation in the presence of DNA gyrase inhibitors. The antibiotic used was nalidixic acid in order to prevent DNA replication, only efficient in Gram-negative bacteria studies. In this study, we describe a new DVC procedure to detect and count viable of L. monocytogenes suspended in filtered, sterilized distilled water. We used different concentrations of ciprofloxacin, efficient both in Gram-negative and Gram-positive bacteria. Bacteria cells were removed and resuspended in BHI broth, with yeast extract and ciprofloxacin. The mixture was incubated at different incubation times at 37 degrees C. After different incubation times, cells were filtered through an isopore polycarbonate black membrane filter and covered with a DAPI solution or orange acridine. The filters were prepared and examined by epifluorescence microscopy. Elongated cells were counted as viable cells, whereas normal size was regarded as nonactive ones. This method allows determination of ciprofloxacin concentration and incubation time optimal to detect maximum viable cells percentage in L. monocytogenes.

Acridine Orange↗
PubMed2006

Spiculopteragia mathevossiani Ruchliadev, 1948 is the minor morph of Spiculopteragia spiculoptera (Gushanskaya, 1931): molecular evidence.

Although Spiculopteragia spiculoptera is primarily a parasite of cervids, it can also but less often contaminate domestic livestock. Little is known about its epidemiology and its pathogenicity in domestic ruminants and other unusual cervid species. Its taxonomic status remains unclear since the hypothesis of morphological polymorphism among males has been proposed. However, accurate taxonomy is fundamental in the identification and survey of potentially pathogenic species of parasites. The second internal transcribed spacer of rDNA (ITS-2) and the mitochondrial (mt) DNA-derived ND4 gene were used to study the polymorphism hypothesis for S. spiculoptera. ND4 evolves more quickly than ITS-2 and is considered to be more discriminant in the characterization of closely related species. DNA sequences of ITS-2 and ND4 were studied in 18 individual males of morphological type spiculoptera and in 3 of morphological type of mathevossiani from Red deer (Cervus elaphus), Roe deer (Capreolus capreolus) and Chamois (Rupicapra rupicapra). Intraindividual ITS-2 variations were detected within and between each morphotype of Spiculopteragia but these differences did not separate the two morphs mathevossiani and spiculoptera. Similarly, although ND4 showed a high level of nucleotide substitution, the morphotypes S. mathevossiani and S. spiculoptera were clustered together. Our genetic data support the dimorphic male hypothesis for the species S. spiculoptera.

Animals↗
PubMed1996

Morphology and toxicity of Abeta-(1-42) dimer derived from neuritic and vascular amyloid deposits of Alzheimer's disease.

In the course of analyzing the chemical composition of Alzheimer's disease neuritic and vascular amyloid, we have purified stable dimeric and trimeric components of Abeta peptides. These peptides (molecular mass 9.0 and 13.5 kDa) were separated by size exclusion chromatography in the presence of 80% formic acid or 5 guanidine thiocyanate, pH 7.4. The average ratio of monomers, dimers, and trimers was 55:30:15, respectively. Similar structures were produced over time upon incubation of synthetic Abeta-(1-42) at pH 7.4. The stability of these oligomeric forms was also demonstrated by Western blot and mass spectrometry. Atomic force microscopy and electron microscopy rotary shadowing revealed that the monomers polymerized into 8-10-nm filaments, whereas the dimers generated prolate ellipsoids measuring 3-4 nm in diameter. The pathogenic effects of the dimeric Abeta-(1-40/42) were tested in cultures of rat hippocampal neuron glia cells. Only in the presence of microglia did the dimer elicit neuronal killing. It is possible that these potentially pathogenic Abeta-(1-40/42) dimers and trimers from Alzheimer's disease amyloid represent the soluble oligomers of Abeta recently described in Alzheimer's disease brains (Kuo, Y.-M., Emmerling, M. R., Vigo-Pelfrey, C., Kasunic, T. C., Kirkpatrick, J. B., Murdoch, G. H., Ball, M. J., and Roher, A. E. (1996) J. Biol. Chem., 271, 4077-4081).

Alzheimer Disease↗