Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Potential pathogens”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7Linked to original sources
PubMed1995

[Potential pathogenic throat bacterial flora in acute successive pharyngitis and tonsillitis in children].

The purpose of this work was to determine the frequency of occurrence of S. aureus, H. influenzae, H. parainfluenzae, beta-hemolytic streptococci, Enterobacteriaceae spp. and nonfermenting rods in a group of children suffering from acute successive pharyngitis and tonsillitis. Specimens were taken during three acute occurrences and twice after treatment from first and second acute occurrences. S. aureus was isolated from the throats of 55.1%-62% of the sick children. H. influenzae and H. parainfluenzae were isolated from about 22% to over 40% of the sick children, beta-haemolytic streptococci were isolated from 10.3%-16.2% of the sick children and Enterobacteriaceae spp. were isolated from the throats of 6.1%-16.25% of the sick children. Nonfermenting rods were isolated from only one sick child. Two or more possible bacterial pathogens were isolated from several sick children. Among them S. aureus with H. influenzae or with H. parainfluenzae or with beta-haemolytic streptococci were most often isolated. After treatment of these children, S. aureus, H. influenzae, H. parainfluenzae were more rarely isolated from the throat, and beta-haemolytic streptococci or Enterobacteriaceae spp. were isolated occasionally. Similarly, after treatment mixed potentially pathogenic bacterial flora were more rarely seen.

Bacteria↗
PubMed1982

The relation of basic biology to pathogenic potential in the genus Chlamydia.

Chlamydiae are obligately intracellular procaryotic parasites, and their activities as agents of human disease are determined to a large degree by their intracellular way of life. The inside of a host cell is a hostile environment, and few microorganisms survive and multiply intracellularly. Those that do have evolved adaptations that fit them for life inside other cells. Apart from the viruses, chlamydiae are the infectious agents most highly adapted to intracellular life. Of all the properties of chlamydiae, the ones most likely to determine their pathogenic potential are those that reflect their adaptations to life inside host cells. Wherever possible, these chlamydial activities will be indentified and described.

Adaptation, Physiological↗
PubMed2004

Limited repertoire of HLA-DRB1*0401-restricted MBP111-129-specific T cells in HLA-DRB1*0401 Tg mice and their pathogenic potential.

Since myelin basic protein (MBP)111-129 is an immunodominant epitope in humans carrying HLA-DRB1*0401, we investigated the encephalitogenic potential of HLA-DRB1*0401-restricted MBP111-129-specific T cells using HLA-DRB1*0401/DRA*0101 transgenic (Tg) mice. Although we could not detect the primary recall response to MBP111-129 peptide after immunization of HLA-DRB1*0401/DRA*0101 Tg mice with human MBP, V beta 10(+) and V beta 2(+) HLA-DRB1*0401-restricted MBP111-129-specific T cells proliferated after restimulation of the lymph node cells with human MBP111-129 in vitro. The V beta 2(+) T cell line recognized only human MBP111-129 in the context of HLA-DRB1*0401, while the V beta 10(+) T cell line recognized both the human and murine MBP111-129 epitopes. Therefore, we examined the encephalitogenic potential of the V beta 10(+) T cell line in HLA-DRB1*0401/DRA*0101 Tg mice by adoptive transfer experiments. The V beta 10(+) T cell line induced mild EAE and inflammatory lesions were observed in the spinal cord and the brainstem. In the spinal cord, the inflammation was observed in the peripheral nerve roots as well as in the CNS. These data suggest the pathogenic potential of HLA-DRB1*0401-restricted MBP111-129-specific T cells in humans.

Adoptive Transfer↗
PubMed1990

Recolonization of anesthetic instruments after regular treatment with potentially pathogenic organisms.

Anesthetic instruments are classified as classes B with regard to sterilization status. This means that washing with soap and water or other detergents is sufficient for reuse. A prospective study was conducted over a 6 month period in the operating (rooms) theatres at Princess Basma Teaching Hospital on anesthetic instruments including laryngoscopes, oxygen masks, airways, tracheal tubes and suction catheters. Fifteen different samples were taken randomly at different sites on these instruments after they had been prepared conventionally for use, and these samples were cultured for bacterial contamination (e.g. P. Aeruginosa). The results showed that potentially pathogenic bacteria were colonizing these instruments. It was concluded that these instruments are important vehicles for transmitting various agents of infection and play an important role in causing nosocomial infections. It is recommended that more effective methods be used for sterilizing these instruments.

Anesthesiology↗
PubMed2001

The prevalence of potential pathogenic bacteria in nasopharyngeal samples from individuals with a respiratory tract infection and a sore throat--implications for the diagnosis of pharyngotonsillitis.

BACKGROUND: Treatment failure in patients with pharyngotonsillitis after a traditional course of penicillin V is a common finding. Several factors have been proposed to explain the failure rate, but the presence of aetiological agents other than group A beta-haemolytic streptococci has attracted little attention. OBJECTIVES: The aim of the present study was to investigate if a nasopharyngeal sample could suggest the aetiology of a sore throat in patients with a respiratory tract infection. METHODS: The prevalence of potentially pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis) in nasopharyngeal samples from 618 healthy individuals was compared with that from 108 patients with a respiratory tract infection and a sore throat. RESULTS: The prevalence of H.influenzae was higher in patients with a sore throat than in healthy individuals of the same age. For the adult patients with a sore throat, the prevalence was 27.5% compared with 2.7% for the healthy carriers (P < 10(-7)). The corresponding figures for schoolchildren were 31.3% versus 6.1% (P = 0.004) and for pre-school children 37.8% versus 13.2% (P = 0.0003). CONCLUSIONS: If H.influenzae is found in a nasopharyngeal sample from a patient with a respiratory tract infection and a sore throat, it might be the aetiological agent.

Adolescent↗
PubMed1997

Ribotypes and virulence gene polymorphisms suggest three distinct Listeria monocytogenes lineages with differences in pathogenic potential.

A total of 133 Listeria monocytogenes isolates were characterized by ribotyping and allelic analysis of the virulence genes hly, actA, and inlA to uncover linkages between independent phylogenetic and specific virulence markers. PCR-restriction fragment length polymorphisms revealed 8 hly, 11 inl4, and 2 actA alleles. The combination of these virulence gene alleles and ribotype patterns separated L. monocytogenes into three distinct lineages. While distinct hly and inlA alleles were generally found to cluster into these three lineages, actA alleles segregated independently. These three phylogenetic lineages were confirmed when 22 partial actA DNA sequences were analyzed. The clinical history of the L. monocytogenes strains showed evidence for differences in pathogenic potential among the three lineages. Lineage I contains all strains isolated during epidemic outbreaks of listeriosis, while no human isolates were found in lineage III. Animal isolates were found in all three lineages. We found evidence that isolates from lineages I and III have a higher plaquing efficiency than lineage II strains in a cell culture assay. Strains from lineage III also seem to form larger plaques than strains from lineage II. A distinctive ribotype fragment and unique 16S rRNA gene sequences furthermore suggest that lineage III might represent a L. monocytogenes subspecies. None of the 20 human isolates available but 11% of our animal isolates were grouped in this lineage, indicating that strains in this lineage might have reduced virulence for humans.

Alleles↗
PubMed1994

Loofah sponges as reservoirs and vehicles in the transmission of potentially pathogenic bacterial species to human skin.

Loofah sponges are natural products used as exfoliative beauty aids. As a consequence of tracing a case of Pseudomonas aeruginosa folliculitis to a contaminated loofah sponge, we assessed the role of loofah sponges in supporting the growth of a wide variety of bacterial species. Our data show growth enhancement of sterile loofah fragments for numerous gram-negative (Pseudomonas, Xanthomonas, and Klebsiella) and gram-positive (Enterococcus and group B Streptococcus) species of human and environmental origin. Furthermore, hydrated new, unused loofah sponges undergo a shift in bacterial flora from sparse colonies of Bacillus spp. and Staphylococcus epidermidis to a predominantly gram-negative flora. The growth-promoting potential of loofah sponges (and other exfoliatives) can be further augmented by desquamated epithelial cells entrapped in the loofah fibrous matrix. Therefore, as loofah sponges (and other exfoliatives) can serve as a reservoir and a vehicle for the transmission of potentially pathogenic species to the human skin, we recommend their decontamination with hypochlorite (10%) bleach at regular intervals.

Bacteria↗
PubMed2006

Influence of sampling technique on detection of potential pathogens in the nasopharynx.

OBJECTIVES: To determine the optimal approach for nasopharyngeal culture and to establish which approach children tolerate best. DESIGN: Cross-sectional study. SETTING: A pediatric otolaryngology department of a Dutch tertiary care hospital. PATIENTS: A cohort of 42 children with chronic suppurative otitis media. INTERVENTION: Paired nasopharyngeal samples were collected transorally and transnasally and cultured for potential aerobic pathogens. MAIN OUTCOME MEASURES: The isolation rate of both samples and the amount of discomfort measured by the visual analog scale. RESULTS: Forty-six (87%) of 53 samples obtained transnasally were culture positive vs 40 (75%) of 53 samples obtained transorally (P = .20). Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Staphylococcus aureus were found more frequently with the transnasal than with the transoral approach: 34% vs 13% (P = .003), 62% vs 51% (P = .20), 30% vs 19% (P = .15), and 21% vs 11% (P = .18), respectively. Mean (SD) visual analog scale scores were 5.3 (1.0) and 3.4 (1.7) (P<.001) for the transnasal and transoral approaches, respectively. CONCLUSIONS: Although the transoral approach is better tolerated in children, the isolation rate of the transnasal approach is higher, especially for S. pneumoniae. The transnasal sampling technique should therefore be the preferred approach for detection of potential pathogens in the nasopharynx in children.

Bacteriological Techniques↗
PubMed1996

The autoimmune reactivity to myelin oligodendrocyte glycoprotein (MOG) in multiple sclerosis is potentially pathogenic: effect of copolymer 1 on MOG-induced disease.

Multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS) characterized by primary demyelination, is believed to result from an autoimmune attack against myelin components. In view of their ability to induce experimental autoimmune encephalomyelitis (EAE), an animal model for MS, the quantitatively major malign proteins--myelin basic protein (MBP) and proteolipid protein (PLP)--have been extensively studied as the relevant primary antigens in MS, and therapeutic approaches have been targeted to counteract autoimmune reactivity to MBP and PLP. Accordingly, copolymer 1, a random synthetic amino acid copolymer crossreactive with MBP and highly protective against the induction of EAE with MBP or PLP, is not being extensively tested in clinical studies as a therapeutic agent for MS. However, increasing evidence suggests that autoimmune reactivity against other CNS-specific myelin proteins could also be involved in the pathogenesis of MS. In this context, we have demonstrated that peripheral blood lymphocytes from patients with MS respond predominantly to myelin oligodendrocyte glycoprotein (MOG) rather than to MBP or PLP, suggesting an important role for cell reactivity against MOG in the pathogenesis of MS. We have demonstrated that T-cell reactivity in MOG can also be pathogenic by inducing neurological disease in H-2u and H-2b mice with the same peptide of MOG, pMOG 35-55. Most interestingly, the expression of the disease differed with the different MHC backgrounds. Induction of a differentially expressed disease in different strains of mice with the same myelin antigen makes this new model particularly relevant to MS, where different expression of the disease is seen in different patients. Therefore, notwithstanding the importance of the autoimmune reactivity to MBP and PLP in MS, the potentially pathogenic autoimmune reactivity to MOG must now also be taken into consideration in therapeutic approaches to MS. In this context, we have investigated the possible effect of copolymer 1 treatment on autoimmune reactivity to MOG and on the development of EAE induced by MOG. Copolymer 1 was found to inhibit the binding of MOG peptides to MHC molecules, as well as the proliferation of MOG-reactive T cells, in a dose-dependent manner. In parallel, injection of copolymer 1 concomitantly with the encephalitogenic MOG peptide exerted a strong protective effect against the development of EAE. These preliminary data on the effect of copolymer 1 on the autoimmune response to MOG in mice indicate that copolymer 1 may also be effective in cases of MS where the autoimmune response to MOG prevails, and should therefore be further investigated in this context.

Animals↗
PubMed1986

Assessment of the potential pathogenicity of type II collagen autoantibodies in patients with rheumatoid arthritis. Evidence of restricted IgG3 subclass expression and activation of complement C5 to C5a.

IgG subclass analysis by enzyme-linked immunosorbent assay of the autoantibody to native type II collagen, detected in 9 patients with classic or definite rheumatoid arthritis, demonstrated a predominance of IgG3 autoantibody. Gm allotyping revealed no obvious association with a particular phenotype. In comparative studies, IgG antibodies to the capsular polysaccharides of pneumococci and tetanus toxoid protein in these same patients consisted predominantly of IgG2 and IgG4. Purified type II collagen autoantibody from 3 of these patients activated complement C5 to C5a when bound to human cartilage in vitro, as measured by radioimmunoassay. These results represent direct evidence of a potential pathogenic role for this autoantibody in rheumatoid arthritis.

Animals↗
PubMed2005

Erythromycin resistance in the commensal throat flora of patients visiting the general practitioner: a reservoir for resistance genes for potential pathogenic bacteria.

The prevalence and mechanism of erythromycin resistance in commensal throat streptococci was determined from October 2000 until December 2002 as part of an ongoing study of the NIVEL in general practice patients (N=678). Resistance prevalence for 1mg/L and 16 mg/L erythromycin was 57% and 20%, respectively. The percentage of total commensal flora resistant within each patient ranged from 1% to 100% (median, 1%). mefA was predominantly found among isolates on the 1mg/L plates, and ermB was found in 64% of the isolates on the 16 mg/L plates. Erythromycin resistance was transferred from a commensal isolate to Streptococcus pneumoniae with a frequency of 1 x 10(-9). Commensal streptococci of general practice patients in The Netherlands form a large reservoir of transferable erythromycin resistance (genes) for potential pathogenic microorganisms.

Anti-Bacterial Agents↗
PubMed2002

Platelet sialic acid as a potential pathogenic factor in coronary heart disease.

It was previously reported that, compared to healthy individuals, patients with coronary heart disease (CHD) exhibit a higher proportion of platelets with lower densities and higher propensity to aggregate. Reasons for this increased tendency to aggregate were unknown but appeared to be independent of the patient's age, gender, or smoking habits. Sialic acid (N-acetyl-neuraminic acid), a negatively charged sugar and constituent of many glycoproteins and gangliosides, is known to confer the bulk of negative charges to mammalian cell surfaces. These negatively charged surfaces can help cells of the bloodstream to maintain a relative distance from each other due to repulsion of the same (negative) charges. In this study, we examined whether differences in platelet sialic acid are a potential pathogenic factor in patients with coronary heart disease. Upon isolating platelets, we found a significantly higher (p < 0.05) proportion of low density platelets in patients compared to healthy controls, which is in accordance with previously published data. We found significantly less (p < 0.05) sialic acid in platelets from patients compared to the control. Most of the platelet total sialic acid was susceptible to cleavage by neuraminidase, demonstrating sialic acid to be preferably localized at the outer platelet surface. We conclude that the lower sialic acid content found in platelets from CHD patients could represent a contributing factor for the observed higher aggregability of platelets from these patients. Due to the lower sialic acid content and resulting lower negative surface charge, less repulsion between the platelets could facilitate aggregation.

Bacterial Proteins↗
PubMed1987

Integrated viral genes as potential pathogens in the functional psychoses.

According to the retrovirus-transposon hypothesis, psychosis is due to the expression of a pathogenic sequence (a "virogene") integrated in the genome and either inherited from an affected or predisposed parent or acquired in the course of reproduction by a genetic rearrangement (e.g. a transposition or the generation of a tandem repeat). The psychoses are viewed as a continuum extending from unipolar through bipolar and schizo-affective disorder to schizophrenia with increasing severity of defect, movement along this continuum occurring by such genetic rearrangements. The locus at which these changes take place is envisaged as related to the genetic determinants of cerebral lateralisation (the "cerebral dominance gene") the interaction between potential pathogen and growth factor gene having possible growth enhancing effects. Such beneficial effects may have ensured the survival of this "hot-spot" in the genome.

Diseases in Twins↗
PubMed1976

Water as a source of potentially pathogenic mycobacteria.

The mycobacterial flora of 321 water samples was explored to evaluate the role of this part of the environment as a possible source of human mycobacterial disease. The samples included natural waters, waters treated to make them suitable for drinking, and waters in contact with animals. Water from the city aquarium contained the greatest abundance of mycobacteria, with an average of 3.5 strains per sample. The highest yield of positive cultures came from samples in contact with zoo animals and with fish. The majority of the isolated strains were slowly growing mycobacteria; 80 were Mycobacterium gordonae, and 34 of thse belong to a new serotype. Forty-seven cultures were members of the M. avian-intracellulare-scrofulaceum complex, of which 11 were typable by agglutination. From this study and from the work of others, it is concluded that water may be contaminated with potentially pathogenic mycobacteria and thus may serve as a source of human disease.

Animals↗
PubMed2006

Screening petting zoo animals for the presence of potentially pathogenic Escherichia coli.

Several outbreaks of Escherichia coli O157 have been reported in petting zoos, resulting in hospitalization of many children. At present, no standard procedure has been adopted to monitor the presence of enterohemorrhagic E. coli (EHEC) or Shiga-toxin-producing E. coli (STEC) in petting zoo animals. Direct detection of these strains from rectal swabs of animals in petting zoos was developed and obviated the need to culture the organisms. DNA extracted from bacteria in the swabs was tested for the presence of wecA gene specific for E. coli by polymerase chain reaction (PCR). The wecA positive samples were further tested for Shiga-toxin genes stxl and stx2, and the intimin eae by multiplex PCR and for the presence of O157 and H7. Swabs (n=104) from 15 animal species in a petting zoo were tested; 7 goats and 3 cows were found to carry STEC. The method is rapid and convenient for monitoring potentially pathogenic E. coli in petting zoo animals.

Animals↗
PubMed1978

Relation between the faecal concentration of various potentially pathogenic microorganisms and infections in individuals (mice) with severely decreased resistance to infection.

Lethally irradiated conventional mice were killed at daily intervals after irradiation. A high correlation was found between the occurrence of bacterial overgrowth in the digestive tract and invasion into the regional lymph nodes the spleen and the blood. By oral contamination of mice with quite high doses of either an exogenous or an endogenous biotype of an Enterobacteriaceae species at day 4 after irradiation, it was attempted to induced such condition of intestinal overgrowth. In all animals such an abnormal colonization of the contaminant was indeed achieved in this way and the mice died from an infection caused by the biotype used for the contamination. The interval between contamination and death was different when different biotypes were used for contamination and occurred sooner after irradiation when an endogenous biotype was used for (re)contamination. It is concluded that oral contamination with exogenous as well as with endogenous potentially pathogenic bacteria during a period of severely decreased resistance to infections must be avoided. The colonization resistance of the digestive tract of these animals should be maintained as high as possible.

Animals↗
PubMed1982

Ionizing radiation in the disinfection of water contaminated with potentially pathogenic mycobacteria.

Sterile drinking water samples were artificially colonized with M. Kansasii, M. gordonae and M. fortuitum suspensions (the numbers of viable unite in 1 ml were 1.2 x 10(3), 48.5 and 3.2 x 10(3), respectively) prepared from mycobacterial strains replicated in Tween 80-free liquid Dubos medium STO. The contaminated water samples were irradiated from a rotary cobalt-60 source (gamma radiation, E = 1.17 and 1.33 MeV, dose intensity 1 kJ/kg.h at room temperature) with doses 0.7, 1.5, 2.2, 3, 9, 16 and 27 kJ/kg. The disinfecting effectiveness was assessed by direct cultivation tests (0.5 ml volumes of water inoculated on egg medium) and by cultivation on membrane filters after filtrating the whole amount of the water examined (about 500 ml). Fully positive disinfecting effects were recorded in M. kansasii and M fortuitum irradiated with 9 kJ/kg and in M. gordonae after irradiation with 1.5 kJ/kg. The calculated value of D10 = 0.4 kJ/kg (i.e. the dose radiation that reduces the number if viable mycobacteria by an order of magnitude) is suggestive of a strong disinfecting effect of ionizing radiation on the tested strains of potentially pathogenic mycobacteria. The results indicate that the use of ionizing radiation to disinfect mycobacteria that are difficult to remove with other methods which, as a rule, cannot ensure the permanent disinfection.

Disinfection↗
PubMed1999

Staphylococcus lugdunensis--a potential pathogen in oral infection.

OBJECTIVE: The purpose of this study was to investigate the pathogenicity of Staphylococcus lugdunensis in acute oral infection. STUDY DESIGN: S. lugdunensis was isolated from patients with acute oral infections and from healthy control subjects. Antibiotic susceptibility, in vitro cellular toxicity, in vivo virulence, and hemolytic activity testing and dot blot analysis were performed. The statistical significance of in vitro cellular toxicity was determined by means of analysis of variance. RESULTS: Isolated from the infected patients, S. lugdunensis showed resistance to penicillin, ampicillin, methicillin, cephalothin, and clindamycin, exhibited virulence in vivo, and showed delta-like hemolysin activity. Four of the 6 strains of S. lugdunensis gave synergistic hemolysis. In dot blot analysis, S. lugdunensis showed a positive reaction to the probe of the delta-hemolysin gene in S. aureus. CONCLUSIONS: The results suggest that S. lugdunensis may be a potential pathogen in acute oral infection.

Abscess↗