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At least 1,063 records · Page 59Linked to original sources
PubMed1997

Risk and the food safety chain: animal health, public health and the environment.

Food safety related to the consumption of animal-derived protein encompasses a wide variety of production and processing procedures which begins with the farm and inputs to the animals on the farm (e.g. feed and water) and includes the environment in which animals are reared. Hazards may be physical, artificial or naturally-occurring chemicals, organisms which cannot reproduce outside a specified life-cycle (e.g., parasites such as tapeworm in pigs) or viruses. Other microbes reproduce in the gastrointestinal tract of food animals as well as on the surface of food and in the environment. Methods of risk assessment for physical and chemical hazards have been used for many years. However, with microbial pathogens which can survive and grow on meat, in soil, water or other media, risk assessment methods are at the early stages of development. Due to the broad habitat range, the role of microbial pathogens in the food safety of meat, poultry, fruit and vegetables is important. The use of antibiotics in livestock species may accelerate the development of antibiotic-resistant strains of microbial pathogens, potentially complicating treatment for both animals and humans. The authors discuss the food chain, risk analysis and hazard analysis and critical control points in relation to foodborne pathogens, and introduce general strategies for improving pathogen control on the farm.

Animals↗
PubMed2001

Selective decontamination of the digestive tract as infection prevention in the critically ill. Does it lead to resistance?

Several meta-analysis showed the efficacy of selective decontamination of the digestive tract (SDD) in the reduction of infections in critically ill patients, particularly for ventilator associated pneumonia and bloodstream infections, thereby reducing mortality and morbidity. The principle of SDD is that by means of application of non-absorbable antibiotics in the intestinal canal and oropharyngeal cavity, potentially pathogenic microorganisms are eliminated, thereby reducing the incidence of organ site infections. The endogenous anaerobic flora is preserved as a factor contributing to defence against colonization. The potential induction of antibiotic resistance (AR) due to SDD is a major concern in ICU. This review evaluates the onset of clinically relevant AR after SDD. The results of a recent meta-analysis and of several studies, which confirmed the virtual absence of any reported AR with SDD and that did not find AR after stopping SDD, are presented. The eradication of the reservoir of abnormal bacteria located in the gut by topical non-absorbable antibiotics appears to significantly reduce morbidity, mortality and resistance. Using only systemic antibiotics in ICU may contribute to maintain an abnormal population of bacteria among which AR is encouraged.

Acute Disease↗
PubMed2005

[Pathogenic properties of free-living amoebae isolated from natural and man-made bathing sites in the province of Western Pomerania].

INTRODUCTION: Pathogenic amoebae belonging to the genus of Acanthamoeba and Naegleria, as well as species such as Balamuthia mandrillaris and Sappinia diploidea cause harmful, life-threatening infections in humans and animals. These amoebae commonly occur in the natural environment. Free-living, pathogenic amoebae have hitherto been detected in water reservoirs near Poznań, Gdańsk, and Lublin. MATERIAL AND METHODS: The present work focused on the occurrence of thermophilic amoebae potentially pathogenic to humans. Natural and man-made bathing sites in the province of Western Pomerania were studied. A total of 299 water samples were collected between 2001 and 2003 from 86 sites (indoor swimming pools, seasonal pools, physiotherapy pool, fountains, lakes, ponds, rivers, lagoons, and coastal waters of the Baltic Sea). Amoebae were isolated at 37 degrees C from 223 samples, of which 34 (15.2%) demonstrated thermophilic properties. Tests using thermophilic isolates were carried out on mice through intranasal inoculation. Pathogenic properties and intensity of infection were determined on the basis of re-isolation of amoebae from agar substrates inoculated with fragments of internal organs. Organs of infected mice were examined histologically. RESULTS: Six isolates exhibited infective properties in mice. Five of them were obtained from two man-made water reservoirs belonging to the recreational complex of the city of Szczecin (AM 17, AM 148, AD 16, AD 148, AD 166). One isolate was from a natural reservoir (JG 172). Amoebae were isolated from the brain, lungs, liver, kidneys, spleen, and heart of the infected animals.

Amoeba↗
PubMed2006

Genotype analysis of human Mycobacterium avium isolates from India.

BACKGROUND & OBJECTIVE: Mycobacterium avium has emerged as a major opportunistic pathogen, infecting nearly 50 per cent of HIV/AIDS patients in the western world. There is no report from India regarding the typing profile of M. avium, a potential pathogen, the present study was undertaken to assess the genotypic diversity of Indian M. avium isolates of human origin. METHODS: A total of 65 biochemically identified M. avium isolates from sputum samples of patients with chronic pulmonary illness were subjected to IS1245 based restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR) typing. RESULTS: IS1245 insertion sequence based RFLP demonstrated polymorphism in 84.6 per cent isolates, while 15.4 per cent isolates did not hybridize on Southern blot and therefore were RFLP negative. Among the 55 RFLP positive isolates, 8 showed 1-3 bands, 19 had bands ranging between 4-9, and 28 isolates had >10 bands each. Although the isolates could be clubbed on the basis of number of bands, the banding profile was highly polymorphic. Among the 55 isolates typeable by RFLP, four clusters and 40 unique types of polymorphism were observed. Application of IS1245 based PCR typing on the same isolates showed that 87.7 per cent isolates were typeable. Interestingly the 10 isolates that were not typeable by IS1245 RFLP were typeable by IS1245 based PCR typing. Among the 57 PCR typed isolates a cluster of 14 isolates with identical 3-banded pattern was observed. Notably, 5 of the ten IS1245 RFLP negative isolates were within this cluster. INTERPRETATION & CONCLUSION: Our results demonstrated that M. avium isolates from India were highly polymorphic with remarkable genetic diversity and heterogeneous RFLP profile. We observed that 47 per cent (n=27) isolates had RFLP profile suggestive of bird and animal origin indicating a strong association with the environment. By applying two typing methods based on IS1245 on the isolates 100 per cent typeability could be achieved.

DNA Transposable Elements↗
PubMed2000

The pathogenic role of point mutations affecting the translational initiation codon of mitochondrial genes.

The mutation T3308C results in a Met --> Thr change at the highly conserved amino acid position 1 of the mtDNA ND1 gene (M1T). To study its potential pathogenic effect we have carried out a combination of mitochondrial protein synthesis and Northern and Western analyses. Our data demonstrate that M1T mutation does not affect the efficiency of the synthesis of the ND1 polypeptide and suggest that any codon specifying methionine located close to the 5' end of mitochondrial mRNAs may be used as translational initiator.

Blotting, Northern↗
PubMed1986

Acute pulpal-alveolar cellulitis syndrome. IV. Exacerbations during endodontic treatment: a clinical study of specific microbial isolates and their etiologic role. Part 1.

A statement has been made by Sundqvist that it has not been possible to isolate the specific bacteria that is responsible for acute exacerbations during endodontic treatment of existing periapical inflammation. This clinical study presents specific microbial isolates from 34 intact nonvital teeth involved with acute cellulitis exacerbations during endodontic therapy. No obligate anaerobes were isolated. Forty-seven aerobic and facultative microbes were isolated. Streptococci, primarily facultative, were the major group of microbes isolated (80%); alpha hemolytic streptococci and the group D enterococcus were predominant as mixed and pure culture specimens. Gram-negative microbes as strict aerobic and facultative microbes were also reported as specific isolates. The biological role of anaerobes were discussed in primary pulpal-periapical infections. The alteration of the tissue oxidation-reduction potential, (Eh) is proposed as an etiologic factor in cellulitis exacerbations during endodontic treatment. This is further substantiated in the Part 2 report. Attention is drawn to the pathogenic potential of streptococci and other microbes isolated in this study.

Acute Disease↗
PubMed2005

Potassium sorbate reduces gastric colonization in patients receiving mechanical ventilation.

OBJECTIVES: Tube feeding might increase gastric burden of pathogenic bacteria and predispose patients to ventilator-associated pneumonia. We sought to determine whether a tube feeding formula acidified using potassium sorbate could reduce gastric burden of potentially pathogenic bacteria. DESIGN: Prospective, randomized, double-blind trial. SETTING: RML Specialty Hospital, a facility with expertise in weaning patients from prolonged mechanical ventilation. PATIENTS: Thirty patients recovering from prolonged mechanical ventilation. INTERVENTION: Patients were randomized to receive either a standard tube feeding formula (n=14) or a formula acidified using potassium sorbate to a pH of 4.25 (n=16). MEASUREMENTS AND RESULTS: Weekly quantitative cultures of gastric aspirates. The number of colony-forming units (CFUs) per patient was higher in the control than in the treatment group (53%+/-11% vs 9%+/-3.4%, threshold of >or=100,000 CFU/mL fluid, P=.003). The number of organisms isolated in each patient per week was higher among patients receiving standard tube feeding formula than among patients receiving acidified formula (0.91 +/- 0.20 vs 0.13 +/- 0.05 organisms per patient per week, threshold of >or=100,000 CFU/mL fluid, P=.0014). There was no difference in the incidence of gastrointestinal bleeding or ventilator-associated pneumonia between study groups. CONCLUSION: Tube feeding formula acidified using potassium sorbate was well tolerated and reduced gastric bacterial burden in patients recovering from prolonged mechanical ventilation.

Aged↗
PubMedDate not supplied

Antibacterial activity of vegetables and juices.

OBJECTIVE: We evaluated the antibacterial activities of various fruit and vegetable extracts on common potential pathogens including antibiotic-resistant strains. METHODS: Standardized bacterial inocula were added to serial dilutions of sterile vegetable and fruit extracts in broth, with final bacterial concentrations of 10(4-5) cells/mL. After overnight incubation at 35 degrees C, antibacterial activity was measured by minimum inhibitory and minimum bactericidal dilutions (for raw juices) or concentrations (for tea). RESULTS: Among the vegetable and fruit extracts tested, all green vegetables showed no antibacterial activity on Staphylococcus epidermidis and Klebsiella pneumoniae. All purple and red vegetable and fruit juices had antibacterial activities in dilutions ranging from 1:2 to 1:16. Garlic juice had significant activity, with bactericidal action in dilutions ranging up to 1:128 of the original juice. Tea also had significant activity, with bactericidal action in concentrations ranging up to 1.6 mg/mL, against a spectrum of pathogens including resistant strains such as methicillin- and ciprofloxacin-resistant staphylococci, vancomycin-resistant enterococci, and ciprofloxacin-resistant Pseudomonas aeruginosa. CONCLUSIONS: Tea and garlic have the potential for exploration of broader applications as antibacterial agents.

Anti-Bacterial Agents↗
PubMed2000

Mycobacterium interjectum: a new pathogen in humans?

Molecular genetic techniques have increased the number of species recognized within the genus Mycobacterium. The clinical significance of these is uncertain and their pathogenic potential has still to be proven. We describe here a case of mycobacterial lymphadenitis in a Swedish boy, which supports the role of M. interjectum as a human pathogen.

Child, Preschool↗
PubMed2000

Association of Mycoplasma genitalium with nongonococcal urethritis in heterosexual men.

Chlamydia trachomatis and Neisseria gonorrhoeae are universally acknowledged as urethral pathogens, yet the etiology in the majority of cases of urethritis is unclear. Our case-control study assessed the association of Mycoplasma genitalium, Ureaplasma urealyticum, and other potential pathogens with acute nongonococcal urethritis (NGU) in heterosexual men presenting to an urban sexually transmitted diseases clinic. M. genitalium was detected in 27 (22%) of 121 NGU case patients and in 5 (4%) of 117 control subjects (P<.01). Although C. trachomatis was detected in 36 (30%) of 121 NGU case patients and in 4 (3%) of 117 control subjects (P<.01), only 3 men with NGU were infected with both C. trachomatis and M. genitalium. U. urealyticum was not associated with NGU. By multivariate analyses, controlling for age, race, history of prior urethritis, and chlamydial infection, M. genitalium was associated with a 6.5-fold increased risk of urethritis (95% confidence interval, 2.1-19.5), which supports a role of this organism in the etiology of NGU.

Adolescent↗
PubMed2000

Aberrant T cell responses to myelin antigens during clinical exacerbation in patients with multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating disease of presumed T cell autoimmunity against self myelin. We hypothesized that if myelin-reactive T cells are associated with the disease processes, they may undergo activation and expansion during acute exacerbation. In this study, we examined the precursor frequency, epitope recognition and cytokine profile of myelin-reactive T cells in 14 relapsing/remitting MS patients during exacerbation and remission. The study revealed that T cells recognizing the immunodominant peptides of candidate myelin antigens, including myelin basic protein (MBP), proteolipid protein and myelin oligodendrocyte glycoprotein, occurred at increased precursor frequency during acute exacerbation. The T cell responses to MBP focused on the immunodominant regions (residues 83-99 and 151-170) during exacerbation and shifted toward other epitopes of MBP at the time of remission. Furthermore, there was a marked increase in the production of T(h)1 cytokines among T cell lines obtained during exacerbation compared to those obtained during remission. The study demonstrated that myelin-reactive T cells underwent selective activation and expansion during acute MS exacerbation. In contrast, myelin-reactive T cells found during remission in the same patients generally resembled those identified in healthy controls with some discrepancies. The findings suggest potential association of aberrant myelin-reactive T cell responses with acute exacerbation in MS, which may reflect transient activation of myelin-reactive T cell populations of pathogenic potential.

Adult↗
PubMed2026

Multimodal genomic surveillance for respiratory pathogens at four U.S. international airports: A comparison of air, wastewater, clinical, and national surveillance data.

Early detection of outbreaks and emerging pathogens is critical for public health and global biosecurity. Airports, as major international travel hubs with dense, enclosed populations, are high-risk settings for disease transmission and potential pathogen introduction. The U.S. Centers for Disease Control and Prevention, in collaboration with Ginkgo Biosecurity and the University of Wisconsin-Madison, implemented air monitoring for pathogen surveillance in congregate areas at four U.S. international airports. From October 2023 to August 2024, SARS-CoV-2 was detected by PCR in 98.3% of air samples and influenza A in 17.2%. Influenza A positivity in air samples correlated with aviation wastewater (r&#x2009;=&#x2009;0.48), traveler nasal swab positivity (r&#x2009;=&#x2009;0.73), and national clinical surveillance (r&#x2009;=&#x2009;0.86), whereas SARS-CoV-2 measurements did not correlate significantly across these modalities. Targeted amplicon sequencing of SARS-CoV-2 from air samples identified contemporaneous lineages also detected in wastewater collected from the same airports. Targeted enrichment sequencing detected 30 viral species and recovered high-quality genomes for SARS-CoV-2, influenza, bocavirus, and seasonal coronaviruses. Together, these findings demonstrate that air sampling can complement aviation wastewater surveillance at ports of entry, although performance and concordance vary by pathogen and sample type.

Journal Article↗
PubMed2006

Nucleic acids modulate autoimmunity through nucleic-acid-specific toll-like receptors.

Autoimmune diseases are believed to develop mainly from three factors comprising genetic predisposition, environmental factors and immune (dys-) regulation. In this context, specific nucleic acids of exogenous or endogenous origin that signal through nucleic acid-specific Toll-like receptors (TLRs) have gained much research attention. During ongoing autoimmune disease microbial nucleic acids contribute to flares of disease and its aggravation leading to end organ damage, through unfavourable immune modulation. Apart from exogenous sources, nucleic acid molecules of endogenous origin emerge as potential ligands for receptors of host defence, i.e. TLRs. Rapidly accumulating data on the role of nucleic acid-specific TLRs has not only provided insights about their pathogenic potential of endogenous nucleic acid molecules, but is also fuelling the development of novel immunotherapies.

Animals↗
PubMed2005

The Pathogenicity of Stachybotrys chartarum.

Stachybotrys chartarum is a dematiaceous fungus that is ubiquitous in our living environment. This fungus has long been regarded as non-pathogenic and its inhalation effect on humans has been scarcely studied. Recently, however, epidemiologic studies on acute idiopathic pulmonary hemorrhage in infants suggested that the fungus might be potentially pathogenic to humans. To determine the pathogenicity of this fungus, its interaction with the host defense system was studied using polymorphonuclear leukocytes (PMNs) and macrophages. Histopathological analysis of mice intratracheally injected with this fungus was also performed. The results disclosed that the conidia of S. chartarum were resistant to the antifungal activities of alveolar macrophages in terms of phagocytosis, killing and inhibition of germination. However, the conidia could not survive in the lungs of mice when injected intratracheally. Lavage fluid of mycelia that contained the dark slimy material coating the surface of conidia showed cytotoxic activity against macrophages and PMNs. Intratracheal injection of conidia in mice resulted in intraalveolar infiltration of PMNs. When using multiple injections during a 3-week period, strong eosinophilic infiltration into the proximal alveoli and perivascular tissues was observed. Our results suggest that inhalation of conidia may cause serious damage to the human lung, particularly when repeated.

Animals↗
PubMed2002

Pentamidine is an inhibitor of PRL phosphatases with anticancer activity.

The PRL family oncogenic phosphatases are attractive targets for developing inhibitors as anticancer therapeutics given their potentially pathogenic role in human malignancies. Herein we demonstrate that pentamidine, an anti-protozoa drug with an unknown mechanism of action, is an inhibitor of PRLs with anticancer potential. Pentamidine at its therapeutic doses inhibited recombinant PRL phosphatases in vitro and inactivated ectopically expressed PRLs in NIH3T3 transfectants with an effective duration more than 24 h after a pulse cell treatment. The drug had in vitro growth-inhibitory activity against human cancer cell lines that express the endogenous PRLs. Pentamidine at a tolerable dose markedly inhibited the growth of WM9 human melanoma tumors in nude mice coincident with the induction of tumor cell necrosis and is capable of inactivating ectopically expressed PRL-2 in the cancer cells. These observations suggest the potential of pentamidine in anticancer therapies and may provide a basis for developing novel PTPase-targeted therapeutics.

3T3 Cells↗
PubMed1992

Concerns regarding infection control recommendations for dental practice.

It goes without saying that the members of any professional group are more likely to modify their behavior if they are provided with logical, rational reasons to enact the suggested change. In the mid 1980s, health care providers, including dental personnel, were advised to adopt universal precautions and to alter their infection control habits with minimal justification, apart from the general unease and paranoia surrounding AIDS. Therefore, it is understandable that some practitioners would react with scepticism to the idea that their traditional infection control techniques were less than adequate, while others would overwhelmingly embrace the new recommendations in the misguided belief that personal, patient, staff and family safety would be enhanced. This predictable confusion is epitomized by the dentist who "sterilizes" extraction forceps by immersing them in alcohol for 10 minutes, versus the dentist who wears gloves, mask and disposable gown to conduct a recall examination. And if dentists are perplexed, it is clear that their staffs are equally, if not more confused, since they are exposed to the exaggerated claims and counter claims of sales agents. The microbes encountered in dental practise, apart from the hepatitis B virus, pose no significant risk to dental personnel or their patients, and the danger of hepatitis B transmission is reduced most effectively by vaccination. In reality, the genesis of dentistry's current emphasis on infection control resides entirely with HIV disease. But there is no credible clinical evidence to suggest that HIV infection is transmitted via dental treatment. Indeed, it may be theorized that for such a transmission to occur, the blood stream of the susceptible recipient would have to be invaded directly by a pathogenic inoculum of the virus--an unlikely event in the normal practise of dentistry. Under such circumstances, infection control practises should ignore the danger of HIV transmission, but concentrate on: Sterilization of all surgical and invasive instruments to protect patients from potential cross-infection. All dental staff receiving hepatitis B vaccinations. Dental staff wearing gloves, especially while performing intraoral procedures with blood release, and handling used instruments, to protect them from direct contact with potential pathogens. Working in a clean environment, in which blood spills and splatters are removed mainly for esthetic reasons. Such measures reflect the actual potential for disease transmission, as it exists in dentistry. They are justified and economical, and will be implemented by concerned but knowledgeable dental staff.

Acquired Immunodeficiency Syndrome↗
PubMed2006

PAMP recognition and the plant-pathogen arms race.

Plants have evolved systems analogous to animal innate immunity that recognise pathogen-associated molecular patterns (PAMPs). PAMP detection is an important component of non-host resistance in plants and serves as an early warning system for the presence of potential pathogens. Binding of a PAMP to the appropriate pattern recognition receptor leads to downstream signalling events and, ultimately, to the induction of basal defence systems. To overcome non-host resistance, pathogens have evolved effectors that target specific regulatory components of the basal defence system. In turn, this has led to the evolution in plants of cultivar-specific resistance mediated by R proteins, which guard the targets of effectors against pathogen manipulation; the arms race continues.

Flagellin↗
PubMed2026

Genomic and phenotypic characterization of mcr-9 carrying Enterobacter oligotrophicus recovered from bovine mastitis.

Bovine mastitis (BM) is a leading cause of economic loss in the dairy industry, driven by decreased milk yields, involuntary culling, and substantial veterinary costs. A single Gram-negative isolate recovered from BM was characterized in this study. For this, antimicrobial susceptibility testing (AST) was performed using the Neg-Urine-Combo 98 panel. Whole-genome sequencing (WGS) was employed to identify antimicrobial resistance genes (ARG), virulence factors (VF) genes, plasmid replicons and prophage sequences. Comparative genomic analysis was performed through phylogenetic analysis. The BM isolate was phenotypically identified as Citrobacter rodentium, however, WGS analysis reclassified the isolate as Enterobacter oligotrophicus. Phenotypic AST revealed a resistance profile of 12%, with the isolate exhibiting resistance to &#x3b2;-lactams antimicrobials, specifically amoxicillin-clavulanate, ampicillin and the cephalosporin-cefoxitin. Conversely, susceptibility was demonstrated for the remaining tested antimicrobials. Genomic profiling identified 31 ARG, 10 VF genes and 6 prophage sequences within the E. oligotrophicus genome. This study provides the first evidence of E. oligotrophicus as a causative agent of BM, expanding the known spectrum of pathogens affecting the dairy industry by delivering the second complete genome of E. oligotrophicus available globally. The identification of 31 ARG, 10 VF, and 6 prophage sequences underscore the potential pathogenic risk and environmental resilience of this isolate. These findings highlight the critical role of WGS-based surveillance in identifying non-conventional mastitis pathogens and underscore the need for targeted mitigation strategies in veterinary medicine.

Animals↗