New approaches to detect and assess the pathogenicity of clinical strains of Yersinia spp. based on molecular biology techniques.
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Adhesins, Bacterial↗
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Results for “pathogen detection”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
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[Prospective detection of important bacterial pathogens in pyoderma and their in vitro antibiotic susceptibility].
BACKGROUND AND OBJECTIVE: For rational therapeutic recommendations the spectrum and resistance of bacteria in skin diseases were investigated. PATIENTS/METHODS: Within 4 months 911 swabs of dematoses possibly caused by bacteria were taken prospectively (481 outpatients, 430 inpatients) and the material cultured on standard media. The positive cultures including resistance screening of 210 swabs of 168 outpatients and of 175 swabs of 85 inpatients could be evaluated, the remaining cultures were sterile. RESULTS: Staphylococcus aureus was the most frequent pathogen (outpatient 67%, inpatient 61% of all positive cultures), followed by streptococci (groups A and B; 25%). In patients Pseudomonas aeruginosa was the most common pathogen in leg ulcers and between the toes (45% and 70% respectively). 13% of the Staphylococcus aureus isolates were resistant to tetracyclines and erythromycin; one strain proved to be methicillin resistant. CONCLUSIONS: Cephalosporins (I. generation), penicillins with beta-lactamase-inhibitors, and to a lesser extent isoxazoyl-penicillin and clindamycin can be recommended for the treatment of skin infections. Oral quinolones are suited for infections with gram-negative bacteria (such as bewteen the toes). The indications for systemic antibiotic therapy of leg ulcers should be restricted.
Bacterial Infections↗
A compact CMOS biochip immunosensor towards the detection of a single bacteria.
Recent use of biological warfare (BW) agents has led to a growing interest in the rapid and sensitive detection of pathogens. Therefore, the development of field-usable detection devices for sensitive and selective detection of BW agents is an important issue. In this work, we report a portable biochip system based on complementary metal oxide semiconductor (CMOS) technology that has great potential as a device for single-bacteria detection. The possibility of single-bacteria detection is reported using an immunoassay coupled to laser-induced fluorescence (LIF) detection. Bacillus globigii spores, which are a surrogate species for B. anthracis spores, were used as the test sample. Enzymatic amplification following immunocomplex formation allowed remarkably sensitive detection of B. globigii spores, and could preclude a complicated optical and instrumental system usually required for high-sensitive detection. Atomic force microscopy (AFM) was employed to investigate whether B. globigii spores detected in the portable biochip system exist in single-cell or multicellular form. It was found that B. globigii spores mostly exist in multicellular form with a small minority of single-cell form. The results showed that the portable biochip system has great potential as a device for single-particle or possibly even single-organism detection.
Bacillus↗
Development of a multi-pathogen oligonucleotide microarray for detection of Bacillus anthracis.
An oligonucleotide microarray system has been specifically designed to detect and differentiate Bacillus anthracis from other bacterial species present in clinical samples. The pilot-scale microarray initially incorporated probes to detect six common species of bacteria, which were fully evaluated. The microarray comprised long oligonucleotides (50--70-mer) designed to hybridise with the variable regions of the 16S rRNA genes. Probes which hybridised to virulence genes were also incorporated; for B. anthracis, these initially included the pag, lef, cap and vrrA (for partial genotyping) genes. Hybridisation conditions were initially optimised to be run using 5 x SSC, 0.1% SDS, 50 degrees C for 16 h. The detection limits of the microarray were determined under these conditions by titration of chromosomal DNA and unlabelled amplicons followed by hybridisation to determine the levels of sensitivity that could be obtained with the microarray. Two different amplification methodologies were also compared-specific-primer based PCR and random PCR (with the labelling stage incorporated). Higher sensitivity was obtained using specific PCR primers, however, since one of the desired outcomes of a microarray-based detection system was the high discrimination that it offered, random amplification and labelling was used as the amplification method of choice. The length of hybridisation was investigated using a time-course, and 1--2h was found to give optimal and higher signals than 16 h incubation. These results indicate that microarray technology can be employed in a diagnostic environment and moreover, results may be obtained in a similar time-scale to a standard PCR reaction, but with the advantage that no a priori knowledge of the infectious agent is required for detection.
Bacillus anthracis↗
Detection of a new pathogenic Babesia microti-like species in dogs.
Small babesiae in dogs are generally considered to belong to Babesia gibsoni. Here we describe the genotypic characterisation of small piroplasms found in the blood of a dog which suffered from clinical babesiosis. Pairwise identities as well as distance, parsimony and maximum likelihood analyses of the 18S rDNA clearly demonstrated that this isolate was only distantly related to the other canine piroplasms characterised genetically so far, including B. gibsoni. It was more closely related to B. microti, B. rodhaini, and Theileria equi. It is concluded that the small canine piroplasms described in this study represent a hitherto unknown species and that the fauna of piroplasms occurring in dogs is more diverse than assumed so far.
Animals↗
Novel detection techniques for human pathogens that contaminate poultry.
Poultry products are presumed to be a major contributor to human foodborne illness due to their high frequency of contamination with pathogens Salmonella spp. and Campylobacter spp. This has stimulated the development of more sensitive and rapid methods for identifying pathogens present in poultry. These new methods include immunomagnetic separation of pathogen, PCR amplification of pathogen-specific sequences, pathogen-specific DNA and RNA probes, and identification of pathogen-specific ions by mass spectrometry.
Animals↗
Comparison of sample collection methods for the PCR detection of oral anaerobic pathogens.
AIMS: To provide evidence that DNA-PCR diagnostics of oral pathogens based on standard sample collection by paper point insertion from the depth of the periodontal pocket can be replaced by a novel non-invasive collection method based on swab technique from the gingiva. METHODS AND RESULTS: In this study we compared the results from two collection methods performed in 35 patients with chronic adult periodontitis. Statistical analysis showed a highly significant association of diagnostic results between both collection techniques. CONCLUSIONS: The Pocket-out method represents a reliable alternative to the standard collection technique for PCR diagnosis of oral pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to its simplicity and non-invasiveness, the Pocket-out collection could be performed in any physician office, or even by the patient himself. With respect to the putative association between periodontal disease and various systemic illnesses, this method could be integrated with various screening programs of oral pathogens.
Adult↗
Pneumocysterol [(24Z)-ethylidenelanost-8-en-3beta-ol], a rare sterol detected in the opportunistic pathogen Pneumocystis carinii hominis: structural identity and chemical synthesis.
Pneumocystis carinii pneumonia (PcP) remains among the most prevalent opportunistic infections among AIDS patients. Currently, drugs used clinically for deep mycosis act by binding ergosterol or disrupting its biosynthesis. Although classified as a fungus, P. carinii lacks ergosterol. Instead, the pathogen synthesizes a number of distinct Delta7, 24-alkylsterols, despite the abundance of cholesterol, which it can scavenge from the lung alveolus. Thus, the pathogen-specific sterols appear vital for organism survival and proliferation. In the present study, high concentrations of a C32 sterol were found in human-derived P. carinii hominis. The definitive structural identities of two C-24 alkylated lanosterol compounds, previously not reported for rat-derived P. carinii carinii, were determined by using GLC, MS, and NMR spectroscopy together with the chemical syntheses of authentic standards. The C31 and C32 sterols were identified as euphorbol (24-methylenelanost-8-en-3beta-ol) and pneumocysterol [(24Z)-ethylidenelanost-8-en-3beta-ol], respectively. The identification of these and other 24-alkylsterols in P. carinii hominis suggests that (i) sterol C-24 methyltransferase activities are extraordinarily high in this organism, (ii) 24-alkylsterols are important components of the pathogen's membranes, because the addition of these side groups onto the sterol side chain requires substantial ATP equivalents, and (iii) the inefficacy of azole drugs against P. carinii can be explained by the ability of this organism to form 24-alkysterols before demethylation of the lanosterol nucleus. Because mammals cannot form 24-alkylsterols, their biosyntheses in P. carinii are attractive targets for the development of chemotherapeutic strategies against this opportunistic infection.
Acquired Immunodeficiency Syndrome↗
Role of Toll-like receptors in inflammatory response in macrophages.
The innate immune response is the first line of defense against infectious disease. It is vital that the host detect the pathogen and rapidly mount a defense. The Toll-like family of receptors have evolved to detect conserved patterns on pathogens. When stimulated, these receptors activate the inflammatory response.
Bacterial Infections↗
A new method of detection and differentiation of pathogenic from non-pathogenic Aspergillus species.
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Aspergillus↗
Enterobacterial chelators of iron: their occurrence, detection, and relation to pathogenicity.
In or on agar media, low-density seedings of enterobacteria fail to grow in the presence of certain concentrations of ethylene diamine-di-orthohydroxyphenyl acetic acid (EDDA); on the other hand, high-density seedings not only grow but secrete iron chelators which release the iron bound by the EDDA in the medium and stimulate the growth of low-density seedings. Plates of media containing EDDA with low-density seedings of indicator organisms were used to survey iron-chelator production in seven enterobacterial genera, including a number of virulent smooth (S) forms from which rough (R) mutants had been obtained. An examination of over 80 strains of Aeromonas, Escherichia, Klebsiella, Proteus, Pseudomonas, Salmonella and Shigella species indicated that the iron chelators from bacteria in all these genera were functionally interchangeable. Chelator production was equally good with randomly selected avirulent and virulent strains of Klebsiella spp. and E. coli; and with the S forms and their avirulent R mutants in one pair of escherichiae, six pairs of salmonellae (4 species) and six pairs of shigellae (3 species). As determinable in vitro, the capacity to synthesise iron chelators is clearly no index of the capacity of a strain to proliferate in vivo.
Aeromonas↗
Detection of opportunistic bacterial pathogens with intrinsic amoxicillin- and cephalosporin-resistance in wild koala faecal microbiomes.
Opportunistic bacterial pathogens frequently associated with human clinical infections, including antimicrobial-resistant strains, are infiltrating the microbiomes of wild animals, where they have the potential to negatively impact wildlife health. Bacterial genes conferring resistance to amoxicillin have previously been reported in koala (Phascolarctos cinereus) faecal DNA. Koalas are facing several key threats, including wildfires, and affected individuals may receive amoxicillin therapy to treat burn wounds. This study aimed to identify the species of amoxicillin-resistant bacteria in koala gut microbiomes and determine if they are opportunistic pathogens. Faecal samples collected from 98 wild-caught koalas were cultured using amoxicillin-supplemented media to isolate amoxicillin-resistant Gram-negative enteric bacteria. Isolates were screened using 16S rRNA PCR and Sanger sequencing to identify opportunistic pathogenic species, which then underwent whole-genome sequencing and antimicrobial susceptibility testing. Intrinsically amoxicillin-resistant opportunistic pathogens were obtained from 9.2% (9/98) of koala faecal samples and comprised Klebsiella oxytoca (6/98, 6.1%), Klebsiella pneumoniae (1/98, 1.0%) and Citrobacter spp. (2/98, 2.0%). Seven of nine amoxicillin-resistant opportunistic pathogens also exhibited cephalosporin resistance. Four K. oxytoca isolates belonged to lineages associated with human clinical infections, which also have the potential to cause disease in koalas, including fatal systemic infections in pouch young. The presence of amoxicillin- and cephalosporin-resistant strains may also increase the risk of gut dysbiosis and opportunistic infections when penicillins or cephalosporins are required to treat bacterial infections in koalas, highlighting the importance of good antimicrobial stewardship. The study findings demonstrate the One Health perspective of microbial pathogens and the intertwined microbial ecology between humans and wildlife.
Animals↗
Genetic probes become ever sharper. Rapid detection of multiple-pathogen infections, including major drug-resistance genes, may be possible using a newly developed technique.
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Biotin↗
Detection and disinfection of pathogens in storm-generated flows.
The disease-producing potential of recreational waters is currently estimated through the use of certain bacterial indicators that are believed to be positively correlated with the presence of fecal contamination. In general, these indicators and their recommended limiting values have been adopted for use from existing standard methods for the analysis of sanitary waste water. However, no indicator currently in use today exists solely in the feces of man and not also elsewhere, e.g., in soils, vegetation, and the feces of animals. Storm-water runoff is often rich in bacteria originating from these nonhuman sources and can contain high densities of indicator bacteria; however, existing epidemiological studies of recreational waters receiving storm-water runoff have reported little correlation between current indicator densities and the incidences of swimming illnesses. In addition, microbial analyses of storm-water runoff have revealed a predominance of nonenteric disease-causing bacteria and viruses that have been linked to respiratory illnesses and skin infections. Fecal-based indicators in use today provide no information on the risks resulting from body contact with these nonenteric pathogens. Consequently, for receiving waters containing discharges that originate primarily from separate storm drainage systems, current bacterial indicators are ill suited to accurately assess the water's total illness-producing capabilities. This paper briefly reviews the development of current bacterial standards and evaluates their adoption in the field of storm-water testing. The unique disinfection requirements of storm-generated runoff are discussed, and advanced disinfection practices are reviewed. The need for additional epidemiological studies that address the disease-causing potential of nonhuman and nonenteric pathogens commonly found in storm-water runoff from urban, agricultural, and rural watershed areas is emphasized in order to determine the actual health risks associated with storm water runoff contact.
Animals↗
Lipopolysaccharide O-antigen antibody-based detection of the fish pathogen Flavobacterium psychrophilum.
Several yellow-pigmented species within the family Flavobacteriaceae are commonly associated with diseases in fish and are difficult to speciate due to their fastidious, slow-growing nature and cross-reactive antigens. Here we report the development of specific, antibody-diagnostic tests for Flavobacterium psychrophilum, the aetiological agent of rainbow trout fry syndrome and bacterial cold water disease. A unique antigen from F. psychrophilum, the lipopolysaccharide (LPS) O-polysaccharide (O-PS), formed the basis for the antibody test. LPS O-PS was purified and conjugated to keyhole limpet haemocyanin and bovine serum albumin for the generation of rabbit immune sera and the development of antibody-based diagnostic tests. Rabbit polyclonal anti-O-PS serum was highly specific for F. psychrophilum, without the need for prior cross-absorption with related bacteria and was the basis of an effective ELISA diagnostic test. Antibodies were purified from rabbit anti-O-PS serum and adsorbed onto coloured latex beads for the development of a specific, bead agglutination assay for F. psychrophilum.
Antibodies, Bacterial↗
Chlamydia pneumoniae. New diagnostic tools for detection of a common pathogen.
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Chlamydia Infections↗
Indirect staining reaction with fluorescent antibody for detection of antibodies to pathogenic fungi.
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Antibodies↗
New technology for detecting multidrug-resistant pathogens in the clinical microbiology laboratory.
Northwestern Memorial Hospital instituted in-house molecular typing to rapidly assess microbial clonality and integrated this typing into an infection control program. We compared data on nosocomial infections collected during 24 months before and 60 months after implementing the new program. During the intervention period, infections per 1,000 patient-days fell 13% (p=0.002) and the percentage of hospitalized patients with nosocomial infections decreased 23% (p=0.000006). In our hospital, the percentage of patients with nosocomial infections is 43% below the U.S. rate. Our typing laboratory costs approximately $400,000 per year, a savings of $5.00 for each dollar spent.
Clinical Laboratory Techniques↗