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1.
J Hosp Infect ; 149: 189-200, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38621512

ABSTRACT

Non-ventilated hospital-acquired pneumonia (NV-HAP) is associated with a significant healthcare burden, arising from high incidence and associated morbidity and mortality. However, accurate identification of cases remains challenging. At present, there is no gold-standard test for the diagnosis of NV-HAP, requiring instead the blending of non-specific signs and investigations. Causative organisms are only identified in a minority of cases. This has significant implications for surveillance, patient outcomes and antimicrobial stewardship. Much of the existing research in HAP has been conducted among ventilated patients. The paucity of dedicated NV-HAP research means that conclusions regarding diagnostic methods, pathology and interventions must largely be extrapolated from work in other settings. Progress is also limited by the lack of a widely agreed definition for NV-HAP. The diagnosis of NV-HAP has large scope for improvement. Consensus regarding a case definition will allow meaningful research to improve understanding of its aetiology and the heterogeneity of outcomes experienced by patients. There is potential to optimize the role of imaging and to incorporate novel techniques to identify likely causative pathogens. This would facilitate both antimicrobial stewardship and surveillance of an important healthcare-associated infection. This narrative review considers the utility of existing methods to diagnose NV-HAP, with a focus on the significance and challenge of identifying pathogens. It discusses the limitations in current techniques, and explores the potential of emergent molecular techniques to improve microbiological diagnosis and outcomes for patients.


Subject(s)
Healthcare-Associated Pneumonia , Humans , Healthcare-Associated Pneumonia/diagnosis , Healthcare-Associated Pneumonia/microbiology , Diagnostic Tests, Routine/methods
2.
Australas J Dermatol ; 64(3): 404-407, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37195732

ABSTRACT

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis presenting primarily with pulmonary and cutaneous features. The disease is typically seen in the fifth or sixth decade of life (1, 2). We report a case of EGPA in an adolescent who was successfully treated with the interleukin-5 (IL-5) receptor inhibitor, benralizumab.


Subject(s)
Churg-Strauss Syndrome , Granulomatosis with Polyangiitis , Adolescent , Humans , Child , Granulomatosis with Polyangiitis/drug therapy , Churg-Strauss Syndrome/drug therapy , Antibodies, Monoclonal, Humanized/therapeutic use
3.
mBio ; 11(1)2020 02 11.
Article in English | MEDLINE | ID: mdl-32047136

ABSTRACT

Enterococcus faecium is a gut commensal of humans and animals but is also listed on the WHO global priority list of multidrug-resistant pathogens. Many of its antibiotic resistance traits reside on plasmids and have the potential to be disseminated by horizontal gene transfer. Here, we present the first comprehensive population-wide analysis of the pan-plasmidome of a clinically important bacterium, by whole-genome sequence analysis of 1,644 isolates from hospital, commensal, and animal sources of E. faecium Long-read sequencing on a selection of isolates resulted in the completion of 305 plasmids that exhibited high levels of sequence modularity. We further investigated the entirety of all plasmids of each isolate (plasmidome) using a combination of short-read sequencing and machine-learning classifiers. Clustering of the plasmid sequences unraveled different E. faecium populations with a clear association with hospitalized patient isolates, suggesting different optimal configurations of plasmids in the hospital environment. The characterization of these populations allowed us to identify common mechanisms of plasmid stabilization such as toxin-antitoxin systems and genes exclusively present in particular plasmidome populations exemplified by copper resistance, phosphotransferase systems, or bacteriocin genes potentially involved in niche adaptation. Based on the distribution of k-mer distances between isolates, we concluded that plasmidomes rather than chromosomes are most informative for source specificity of E. faeciumIMPORTANCEEnterococcus faecium is one of the most frequent nosocomial pathogens of hospital-acquired infections. E. faecium has gained resistance against most commonly available antibiotics, most notably, against ampicillin, gentamicin, and vancomycin, which renders infections difficult to treat. Many antibiotic resistance traits, in particular, vancomycin resistance, can be encoded in autonomous and extrachromosomal elements called plasmids. These sequences can be disseminated to other isolates by horizontal gene transfer and confer novel mechanisms to source specificity. In our study, we elucidated the total plasmid content, referred to as the plasmidome, of 1,644 E. faecium isolates by using short- and long-read whole-genome technologies with the combination of a machine-learning classifier. This was fundamental to investigate the full collection of plasmid sequences present in our collection (pan-plasmidome) and to observe the potential transfer of plasmid sequences between E. faecium hosts. We observed that E. faecium isolates from hospitalized patients carried a larger number of plasmid sequences compared to that from other sources, and they elucidated different configurations of plasmidome populations in the hospital environment. We assessed the contribution of different genomic components and observed that plasmid sequences have the highest contribution to source specificity. Our study suggests that E. faecium plasmids are regulated by complex ecological constraints rather than physical interaction between hosts.


Subject(s)
Cross Infection/microbiology , Enterococcus faecium/genetics , Enterococcus faecium/pathogenicity , Genome, Bacterial , Plasmids/genetics , Anti-Bacterial Agents/pharmacology , DNA Transposable Elements/genetics , Enterococcus faecium/drug effects , Gene Transfer, Horizontal , Genomics , Gram-Positive Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/transmission , Hospitals , Humans , Phylogeny , Sequence Analysis, DNA , Whole Genome Sequencing
4.
J Hosp Infect ; 104(4): 492-496, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31606433

ABSTRACT

Carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates (carrying the carbapenemase gene blaNDM-5) of sequence type 16 caused hospital-acquired bloodstream infection or gut colonization in two patients in an intensive care unit (ICU). It was hypothesized that handwashing sinks were the source, and all handwashing sinks in the ICU were sampled. Whole-genome sequencing and analysis revealed that one sink was the source of CRKP colonization/infection in both patients, instead of direct transmission of a common clone between the patients. This study highlights handwashing sinks as an important source of multi-drug-resistant organisms. Sink management, including prohibition of disposal of body fluids and daily disinfection with chlorine, curbed the transmission.


Subject(s)
Carbapenem-Resistant Enterobacteriaceae/genetics , Carbapenem-Resistant Enterobacteriaceae/isolation & purification , Klebsiella pneumoniae/genetics , Klebsiella pneumoniae/isolation & purification , Wastewater/microbiology , Water Microbiology , China , Cross Infection , Databases, Nucleic Acid , Hand Disinfection , Humans , Intensive Care Units , Klebsiella Infections , Whole Genome Sequencing
6.
Chem Sci ; 6(2): 1277-1281, 2015 Feb 01.
Article in English | MEDLINE | ID: mdl-29541441

ABSTRACT

A mild and transition metal-free counteranion triggered arylation strategy has been developed using diaryliodonium fluorides. The fluoride counteranion within the hypervalent iodonium species displays unusual reactivity that activates a phenolic O-H bond leading to electrophilic O-arylation. A wide range of phenols and diaryliodonium salts are compatible with this transformation under remarkably mild conditions. Furthermore, we pre-empt the wider implications of this strategy by demonstrating the compatibility of the arylation tactic with latent carbon nucleophiles.

7.
Clin Microbiol Infect ; 19(8): E328-34, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23573792

ABSTRACT

Urosepsis is a bacteraemia infection caused by an organism previously causing an infection in the urinary tract of a patient, a diagnosis which has been classically confirmed by culture of the same species of bacteria from both blood and urine samples. Given the new insights afforded by sequencing technologies into the complicated population structures of infectious agents affecting humans, we sought to investigate urosepsis by comparing the genome sequences of blood and urine isolates of Escherichia coli from five patients with urosepsis. The results confirm the classical urosepsis hypothesis in four of the five cases, but also show the complex nature of extra-intestinal E. coli infection in the fifth case, where three distinct strains caused two distinct infections. Additionally, we show there is little to no variation in the bacterial genome as it progressed from urine to blood, and also present a minimal set of virulence genes required for bacteraemia in E. coli based on gene association. These suggest that most E. coli have the genetic propensity to cause bacteraemia.


Subject(s)
Bacteremia/microbiology , Escherichia coli Infections/microbiology , Escherichia coli/classification , Escherichia coli/genetics , Urinary Tract Infections/complications , Aged, 80 and over , Escherichia coli/isolation & purification , Escherichia coli/pathogenicity , Escherichia coli Proteins/genetics , Female , Genome, Bacterial , Genotype , Humans , Male , Middle Aged , Multilocus Sequence Typing , Polymorphism, Single Nucleotide , Virulence Factors/genetics
9.
Avian Pathol ; 39(4): 265-73, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20706882

ABSTRACT

A range of virus doses were used to infect 3-week-old chickens, turkeys and ducks intranasally/intraocularly, and infection was confirmed by the detection of virus shedding from the buccal or cloacal route by analysis of swabs collected using real-time reverse transcriptase-polymerase chain reaction assays. The median infectious dose (ID(50)) and the median lethal dose (LD(50)) values for two highly pathogenic avian influenza (HPAI) viruses of H5N1 and H7N1 subtypes and one virulent Newcastle disease virus (NDV) were determined for each virus and host combination. For both HPAI viruses, turkeys were >100-fold more susceptible to infection than chickens, while both these hosts were >10-fold more susceptible to H5N1 virus than the H7N1 virus. All infected chickens and turkeys died. Ducks were also much more readily infected with the H5N1 virus (ID(50)< or =10(1) median embryo infective dose [EID(50)]) than the H7N1 virus (ID(50)=10(4.2) EID(50)). However, the most notable difference between the two viruses was their virulence for ducks, with a LD(50) of 10(3) EID(50) for the H5N1 virus, but no deaths in ducks being attributed to infection with H7N1 virus even at the highest dose (10(6) EID(50)). For both HPAI virus infections of ducks, the ID(50) was lower than the LD(50), indicating that infected birds were able to survive and thus excrete virus over a longer period than chickens and turkeys. The NDV strain used did not appear to establish infection in ducks even at the highest dose used (10(6) EID(50)). Some turkeys challenged with 10(6) EID(50), but not other doses, of NDV excreted virus for a number of days (ID(50)=10(4.6) EID(50)), but none died. In marked contrast, chickens were shown to be extremely susceptible to infection and all infected chickens died (ID(50)/LD(50)=10(1.9) EID(50)).


Subject(s)
Chickens , Ducks , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza in Birds/physiopathology , Newcastle Disease/physiopathology , Newcastle disease virus/pathogenicity , Turkeys , Animals , Influenza A Virus, H5N1 Subtype/genetics , Influenza in Birds/mortality , Lethal Dose 50 , Newcastle Disease/mortality , Newcastle disease virus/genetics , Reverse Transcriptase Polymerase Chain Reaction , Species Specificity , Virulence , Virus Shedding/physiology
10.
Epidemiol Infect ; 136(6): 739-51, 2008 Jun.
Article in English | MEDLINE | ID: mdl-17655782

ABSTRACT

An abattoir survey was undertaken to determine the prevalence of foodborne zoonotic organisms colonizing cattle, sheep and pigs at slaughter in Great Britain. The study ran for 12 months from January 2003, involved 93 abattoirs and collected 7703 intestinal samples. The design was similar to two previous abattoir surveys undertaken in 1999-2000 allowing comparisons. Samples were examined for VTEC O157, Salmonella, thermophilic Campylobacter and Yersinia enterocolitica. The prevalence of VTEC O157 faecal carriage was 4.7% in cattle, 0.7% in sheep and 0.3% in pigs. A significant decrease in sheep was detected from the previous survey (1.7%). Salmonella carriage was 1.4% in cattle, a significant increase from the previous survey of 0.2%. In sheep, faecal carriage was 1.1% a significant increase from the previous survey (0.1%). In pigs, carriage was 23.4%, consistent with the previous study. Thermophilic Campylobacter spp. were isolated from 54.6% of cattle, 43.8% of sheep and 69.3% of pigs. Y. enterocolitica was isolated from 4.5% of cattle, 8.0% of sheep and 10.2% of pigs.


Subject(s)
Campylobacter/isolation & purification , Carrier State/veterinary , Escherichia coli O157/isolation & purification , Food Contamination , Meat/microbiology , Salmonella/isolation & purification , Yersinia enterocolitica/isolation & purification , Abattoirs , Animals , Carrier State/epidemiology , Carrier State/microbiology , Cattle , Feces/microbiology , Prevalence , Sheep , Swine , United Kingdom/epidemiology , Zoonoses/microbiology
11.
Neurotoxicology ; 28(6): 1110-9, 2007 Nov.
Article in English | MEDLINE | ID: mdl-17669499

ABSTRACT

Circulating uranium rapidly enters the brain and may cause adverse effects on the nervous system that are potentially modulated by stress. In this study, the neurological effects of a single intramuscular injection of 0, 0.1, 0.3, or 1 mg uranium/kg (as uranyl acetate, UA) in rats were examined in the presence and absence of stress. Treatment with UA produced time and dose-dependent increases in serum and regional brain uranium levels. While serum levels returned to control levels by day 30, brain levels remained elevated. Application of stress did not affect the distribution or retention of uranium. Exposure to 1 mg U/kg significantly decreased ambulatory activity, weight gain, forelimb grip strength and transiently impaired working memory. Effects on grip strength and memory were prevented by application of stress prior to uranium exposure. Striatal dopamine content was reduced by 30% 3 days after treatment with 1mg/kg (59+/-6 nmol/mg tissue versus 41+/-5 nmol/mg tissue), but levels returned to control 7 days after uranium exposure. The effect on dopamine was ameliorated by prior application of stress. Exposure to UA did not alter 3,4 dihydroxyphenylacetic acid (DOPAC) levels or numbers of D2 receptors in the striatum. No effect of uranium or stress was observed on levels of GABA, serotonin, norepinephrine, or glutathione (GSH) in the striatum, hippocampus, cerebellum, or cortex. These results indicate that single intramuscular exposures to uranium produce sustained elevation of brain uranium levels and at doses above 0.3 mg/kg can have adverse neurological effects. Application of stress prior to uranium administration modulates neurological effects, but the mechanism is not due to effects on uranium distribution. Uranium exposure also produced renal toxicity which must be considered to accurately assess the effects of uranium on neurological function.


Subject(s)
Behavior, Animal/drug effects , Brain/drug effects , Neurotoxicity Syndromes/etiology , Organometallic Compounds/toxicity , Stress, Psychological/complications , Animals , Body Weight/drug effects , Brain/metabolism , Brain/physiopathology , Brain Chemistry/drug effects , Corticosterone/blood , Dopamine/metabolism , Dose-Response Relationship, Drug , Glutathione/metabolism , Injections, Intramuscular , Kidney Diseases/chemically induced , Locomotion/drug effects , Male , Memory/drug effects , Muscle Strength/drug effects , Neurotoxicity Syndromes/complications , Neurotoxicity Syndromes/metabolism , Neurotoxicity Syndromes/physiopathology , Neurotransmitter Agents/metabolism , Organometallic Compounds/administration & dosage , Organometallic Compounds/pharmacokinetics , Rats , Rats, Sprague-Dawley , Stress, Psychological/metabolism , Stress, Psychological/physiopathology , Time Factors , Tissue Distribution
12.
Avian Dis ; 51(1 Suppl): 373-7, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17494587

ABSTRACT

Real time reverse transcriptase (RRT)-polymerase chain reaction (PCR) for the detection of Eurasian H5 avian influenza virus (AIV) isolates was adapted from an existing protocol, optimized, and validated using a number of genetically diverse H5 isolates (n = 51). These included 34 "Asian lineage" H5N1 highly pathogenic avian influenza (HPAI) viruses (2004-2006), plus 12 other H5 isolates from poultry outbreaks and wild birds in the Eastern Hemisphere (1996-2005). All 51 were positive by H5 Eurasian RRT-PCR. Specificity was assessed by testing representative isolates from all other AL virus subtypes (n = 52), non-AI avian pathogens (n = 8), plus a negative population of clinical specimens derived from AI-uninfected wild birds and poultry (n = 604); all were negative by H5 Eurasian RRT-PCR. RNA was directly extracted from suspect HPAI H5N1 clinical specimens (Africa, Asia, and Europe; 2005-2006; n = 58) from dead poultry and wild birds, and 55 recorded as positive by H5 Eurasian RRT-PCR: Fifty-one of these 55 were in agreement with positive AIV isolation in embryonated chickens' eggs. H5 Eurasian RRT-PCR was invaluable in H5 outbreak diagnosis and management by virtue of its rapidity and high degree of sensitivity and specificity. This method provides a platform for automation that can be applied for large-scale intensive investigations, including surveillance.


Subject(s)
Disease Outbreaks/veterinary , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza in Birds/epidemiology , Reverse Transcriptase Polymerase Chain Reaction/veterinary , Animals , Birds/virology , Influenza in Birds/virology , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity , Time Factors
13.
Lett Appl Microbiol ; 39(1): 103-8, 2004.
Article in English | MEDLINE | ID: mdl-15189296

ABSTRACT

AIMS: To investigate the relationship between livestock carriage of Yersinia enterocolitica and human disease. The biotypes/serotypes of strains recovered from the faeces of pigs, cattle and sheep at slaughter during a national survey in Great Britain in 1999-2000, were compared with those of strains isolated from human cases of yersiniosis during the same period. METHODS AND RESULTS: The faecal carriage of Y. enterocolitica by cattle, sheep and pigs at slaughter was 6.3, 10.7 and 26.1%, respectively. Yersinia enterocolitica biotype (BT) 1a was the most frequently isolated biotype from livestock (58%) and was the predominant biotype (53%) isolated from human cases over the same period. The main recognized pathogenic Y. enterocolitica biotype isolated from livestock was BT3 (O:5,27) (35% of sheep, 22% of pigs and 4% of cattle) but this biotype was not detected in any of the human isolates investigated. The major pathogenic biotypes of strains isolated from humans were BT3 (O:9) (24%) and BT4 (O:3) (19%) whereas of the veterinary isolates investigated, only pigs (11%) carried BT3 (O:9) strains. CONCLUSIONS: Because of significant overlaps in phenotypes of the veterinary and human strains it is not possible to comment on the correlation between host and pathogenicity, especially of biotype 1a. SIGNIFICANCE AND IMPACT OF THE STUDY: The data suggest that further investigations using methods with greater discriminatory power are required. However the data also suggests that pigs may be the primary reservoir for human pathogenic Y. enterocolitica infection.


Subject(s)
Abattoirs , Animals, Domestic/microbiology , Yersinia Infections/microbiology , Yersinia enterocolitica/classification , Animals , Cattle/microbiology , Cattle Diseases/microbiology , Humans , Sheep/microbiology , Sheep Diseases/microbiology , Swine/microbiology , Swine Diseases/microbiology , Yersinia Infections/veterinary , Yersinia enterocolitica/pathogenicity , Yersinia enterocolitica/physiology
14.
Crit Care Med ; 31(1): 39-44, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12544991

ABSTRACT

UNLABELLED: OBJECTIVE To evaluate the efficacy of intravenous erythromycin as a method to facilitate feeding tube placement into the small intestine in critically ill patients. DESIGN Double blind, randomized, controlled trial. SETTING Medical and surgical intensive care units in an academic medical center. PATIENTS Prospective cohort of 36 consecutive adults requiring intensive care unit care and enteral tube feeding for nutritional support. INTERVENTION Infusion of a single dose of intravenous erythromycin (500 mg) or saline before placement of 10-Fr feeding tubes using a standardized active bedside protocol. MEASUREMENTS AND MAIN RESULTS We determined the success rate of feeding tube placement into or beyond the second portion of the duodenum and the time required for this procedure by experienced nurses. The feeding tube was considered to be postpyloric when the tip was in the second portion of the duodenum or beyond. The predictive value of a serial step-up in gastrointestinal aspirate pH from < or = 5.0 to > or = 6.0 was also determined. Use of intravenous erythromycin significantly improved the rate of feeding tube placement into the duodenum or jejunum (erythromycin group, 13 of 14 patients or 93% vs. the control group, 12 of 22 patients or 55%; p < .03). Erythromycin administration also significantly decreased the procedure time from 25 +/- 3 to 15 +/- 2 mins (p < .04). Feeding tube placement into either duodenum or jejunum was confirmed in all 18 patients with a pH step-up from < or = 5.0 to > or = 6.0. CONCLUSION: A single bolus dose of intravenous erythromycin facilitates active bedside placement of postpyloric feeding tubes in critically ill adult patients.


Subject(s)
Enteral Nutrition , Erythromycin/therapeutic use , Gastrointestinal Agents/therapeutic use , Intubation, Gastrointestinal/methods , Critical Illness , Double-Blind Method , Female , Humans , Infusions, Intravenous , Male , Middle Aged
15.
Addict Behav ; 26(5): 721-34, 2001.
Article in English | MEDLINE | ID: mdl-11676381

ABSTRACT

While expectancies are considered to be an important cognitive variable in the etiology and maintenance of substance use, less is known about their role in attitudes toward addictive behavior change. It has recently been suggested that negative alcohol expectancies, in particular, might play a fundamental role in motivation to change. Among a population of college student binge drinkers, the differential ability of positive and negative expectancies to predict total readiness to change (RTC) scores was examined. Hierarchical regression analyses revealed that controlling for level of consumption and number of drinking-related problems, negative and not positive expectancies significantly predicted RTC. In an examination of expectancy subtypes, negative emotional expectancies emerged as the only significant predictor of change motivation. Possible explanations for the findings and implications for interventions with undergraduate heavy drinkers are discussed.


Subject(s)
Alcohol Drinking/psychology , Emotions , Set, Psychology , Adolescent , Adult , Alcohol-Related Disorders/psychology , Analysis of Variance , Attitude , Decision Making , Female , Humans , Male , Risk-Taking , Students
16.
Infect Immun ; 69(8): 5107-14, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11447192

ABSTRACT

Ongoing extensive epidemiological studies of verotoxin-carrying Escherichia coli O157 (stx(+) eae(+)) have shown this bacterial pathogen to be common in cattle herds in the United States and the United Kingdom. However, the incidence of disease in humans due to this pathogen is still very low. This study set out to investigate if there is a difference between strains isolated from human disease cases and those isolated from asymptomatic cattle which would account for the low disease incidence of such a ubiquitous organism. The work presented here has compared human disease strains from both sporadic and outbreak cases with a cross-section, as defined by pulsed-field gel electrophoresis, of E. coli O157 strains from cattle. Human (n = 22) and bovine (n = 31) strains were genotyped for carriage of the genes for Shiga-like toxin types 1, 2, and 2c; E. coli secreted protein genes espA, espB, and espP; the enterohemolysin gene; eae (intimin); ast (enteroaggregative E. coli stable toxin [EAST]); and genes for common E. coli adhesins. Strains were also phenotyped for hemolysin, EspP, Tir, and EspD expression as well as production of actin and cytoskeletal rearrangement associated with attaching and effacing (A/E) lesions on HeLa cells. The genotyping confirmed that there was little difference between the two groups, including carriage of stx(2) and stx(2c), which was similar in both sets. ast alleles were confirmed to all contain mutations that would prevent EAST expression. espP mutations were found only in cattle strains (5 of 30). Clear differences were observed in the expression of locus of enterocyte effacement (LEE)-encoded factors between strains and in different media. EspD, as an indicator of LEE4 (espA, -B, and -D) expression, and Tir levels in supernatants were measured. Virtually all strains from both sources could produce EspD in Luria-Bertani broth, although at very different levels. Standard trichloroacetic acid precipitation of secreted proteins from tissue culture medium produced detectable levels of EspD from the majority of strains of human origin (15 of 20) compared with only a few (4 of 20) bovine strains (P < 0.001), which is indicative of much higher levels of protein secretion from the human strains. Addition of bovine serum albumin carrier protein before precipitation and enhanced detection techniques confirmed that EspD could be detected after growth in tissue culture medium for all strains, but levels from strains of human origin were on average 90-fold higher than those from strains of bovine origin. In general, levels of secretion also correlated with ability to form A/E lesions on HeLa cells, with only the high-level protein secretors in tissue culture medium exhibiting a localized adherence phenotype. This research shows significant differences between human- and bovine-derived E. coli O157 (stx(+) eae(+)) strains and their production of certain LEE-encoded virulence factors. These data support the recent finding of Kim et al. (J. Kim, J. Nietfeldt, and A. K. Benson, Proc. Natl. Acad. Sci. USA 96:13288-13293, 1999) proposing different E. coli O157 lineages in cattle and humans and extend the differential to the regulation of virulence factors. Potentially only a subset of E. coli O157 isolates (stx(+) eae(+)) in cattle may be capable of causing severe disease in humans.


Subject(s)
Bacterial Proteins/genetics , Escherichia coli Infections/microbiology , Escherichia coli O157/genetics , Escherichia coli Proteins , Proteins , Adhesins, Bacterial/genetics , Animals , Bacterial Toxins/genetics , Cattle , Disease Outbreaks , Enterocytes , Escherichia coli Infections/epidemiology , Escherichia coli Infections/veterinary , Escherichia coli O157/isolation & purification , HeLa Cells , Humans , Interleukin-6 , Leukemia Inhibitory Factor , Molecular Chaperones/genetics , Serine Endopeptidases/genetics , Shiga Toxin 1/genetics , Shiga Toxin 2/genetics
17.
J Anal Toxicol ; 25(4): 258-69, 2001.
Article in English | MEDLINE | ID: mdl-11386639

ABSTRACT

The abuse of the designer amphetamines such as 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) is increasing throughout the world. They have become popular drugs, especially at all-night techno dance parties (Raves), and their detection is becoming an important issue. Presently, there are no MDMA- or MDA-specific immunoassays on the market, and detection of the designer amphetamines is dependent upon the use of commercially available amphetamine assays. The success of this approach has been difficult to assess because of the general unavailability of significant numbers of samples from known drug users. The objectives of the present study are to characterize the drug content of urine samples from admitted Ecstasy users by chromatographic methods and to assess the ability of the available amphetamine/methamphetamine immunoassays to detect methylenedioxyamphetamines. We found that, when analyzed by high-performance liquid chromatography with diode-array detection (HPLC-DAD), 64% of 70 urine samples (by gas chromatography-mass spectrometry [GC-MS]: 88% of 64 urine samples) obtained from Rave attendees contained MDMA and/or 3,4-methylenedioxyamphetamine (MDA) alone or in combination with amphetamine, methamphetamine, or other designer amphetamines such as 3,4-methylenedioxyethylamphetamine (MDEA). This suggests that the majority of the Ravers are multidrug users. At the manufacturer's suggested cutoffs, the Abbott TDx Amphetamine/Methamphetamine II and the new Roche HS Amphetamine/MDMA assays demonstrated greater detection sensitivity for MDMA than the other amphetamine immunoassays tested (Abuscreen OnLine Hitachi AMPS, Abuscreen OnLine Integra AMPS, Abuscreen OnLine Integra AMPSX, CEDIA AMPS, and EMIT II AMPS). There is 100% agreement between each of the two immunoassays with the reference chromatographic methods, HPLC-DAD and GC-MS, for the detection of methylenedioxyamphetamines.


Subject(s)
Central Nervous System Stimulants/urine , Hallucinogens/urine , Illicit Drugs/urine , Immunoassay/methods , N-Methyl-3,4-methylenedioxyamphetamine/urine , Chromatography, High Pressure Liquid/methods , Gas Chromatography-Mass Spectrometry/methods , Hallucinogens/chemistry , Hallucinogens/toxicity , Humans , Illicit Drugs/chemistry , Illicit Drugs/toxicity , N-Methyl-3,4-methylenedioxyamphetamine/chemistry , N-Methyl-3,4-methylenedioxyamphetamine/toxicity , Sensitivity and Specificity , Substance Abuse Detection/methods
18.
J Forensic Sci ; 46(2): 335-40, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11305436

ABSTRACT

The catalytic rates of hydrolysis of lorazepam-glucuronide, oxazepam-glucuronide, and temazepam-glucuronide when catalyzed by E. Coli. beta-glucuronidase both in phosphate buffer and buffered drug-free urine were compared as well as the pH dependence of enzyme activity. In 50 mM phosphate buffer pH 6.4, lorazepam-glucuronide has the highest turnover rate of 3.7 s(-1) with an associated Km of about 100 microM, followed by oxazepam-glucuronide, which has a turnover rate of 2.4 s(-1) with an associated Km of 60 microM. Temazepam-glucuronide has the lowest rate of 0.94 s(-1) with an associated Km of 34 microM. In buffered drug-free urine, a similar trend was observed. In addition, an optimal pH for beta-glucuronidase was determined to be between 6 and 7 when the enzyme hydrolyzes the benzodiazepine conjugates in buffered drug-free urine. Effects of temperature and incubation time were also examined. It can be concluded that the electron donating or withdrawing of the individual benzodiazepine structure may play an important role in the reactivity of the lorazepam-glucuronide, oxazepam-glucuronide and temazepam-glucuronide catalyzed by beta-glucuronidase. This is consistent with other observations made for monosubstituted phenyl-beta-glucuronides by Wang et al. (1).


Subject(s)
Anti-Anxiety Agents/metabolism , Escherichia coli/enzymology , Lorazepam/metabolism , Oxazepam/metabolism , Temazepam/metabolism , Anti-Anxiety Agents/pharmacokinetics , Forensic Medicine/methods , Glucuronidase/metabolism , Glucuronides/analysis , Glucuronides/chemistry , Humans , Hydrogen-Ion Concentration , Hydrolysis , Immunoassay , Lorazepam/pharmacokinetics , Oxazepam/pharmacokinetics , Temazepam/pharmacokinetics , Temperature , Urinalysis
19.
J Anal Toxicol ; 25(8): 699-704, 2001.
Article in English | MEDLINE | ID: mdl-11765027

ABSTRACT

A clinical study was conducted to assess the ability of commercially available immunoassays to detect flunitrazepam (FNP) in plasma and urine samples and to compare the results with those obtained by gas chromatography-mass spectrometry (GC-MS). The clinical study consisted of four individuals (two male and two female) who had taken a single 2-mg dose of FNP. Serum was collected over a 48-h period and urine was collected over a 72-h period. The serum and urine samples were analyzed by the COBAS INTEGRA Serum Benzodiazepines assay (SBENZ), the TDx serum and urine Benzodiazepines assay, and GC-MS. The GC-MS procedure was developed for analysis of FNP and metabolites in plasma and urine using an acid hydrolysis step resulting in the formation of specific benzophenones corresponding to FNP and its metabolites. The relative sensitivities of the assays for the detection of FNP and metabolites in serum and urine were GC-MS > SBENZ > TDx. The immunoassay results for serum samples showed peak concentrations of FNP metabolites at 8 h after FNP ingestion for three individuals and at about 1 h for the fourth individual. The GC-MS, SBENZ, and TDx urine immunoassays detected drug above the stated limit of detection (LOD) in 44, 41, and 35 serial FNP urine samples, respectively. FNP metabolites were detected in urine samples with all three assays for up to 72 h after a 2-mg dose. The improved detection rate with the SBENZ assay as compared to the TDx assay is likely explained by its higher cross-reactivity with the major metabolite, 7-amino-flunitrazepam (7-amino-FNP), and its lower LOD.


Subject(s)
Anti-Anxiety Agents/blood , Anti-Anxiety Agents/urine , Flunitrazepam/analogs & derivatives , Flunitrazepam/blood , Flunitrazepam/urine , Immunoassay/standards , Administration, Oral , Adult , Anti-Anxiety Agents/metabolism , Female , Flunitrazepam/metabolism , Gas Chromatography-Mass Spectrometry , Humans , Male , Sensitivity and Specificity , Substance Abuse Detection
20.
Hum Factors ; 41(2): 194-204, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10422531

ABSTRACT

Automated telephone messaging systems have dramatically expanded communication about health service appointments, but few studies have directly investigated these messages. The present study investigated whether message repetition (1, 2, or 3 presentations) and listener age (mean age = 71 or 19 years) improved memory for automated appointment messages. Repetition improved older and younger adult memory for appointment information. Moreover, 2 presentations reduced age differences in accuracy of answering questions about the messages. This was not the case for free recall, suggesting that older adults differentially benefited from repetition only when provided with additional retrieval support. These findings show that older as well as younger adults benefit from at least 1 repetition of appointment messages. Actual or potential applications of this research include the use of repetition to improve comprehension of automated telephone messages.


Subject(s)
Aging/physiology , Appointments and Schedules , Mental Recall , Reminder Systems , Telephone , Adult , Aged , Analysis of Variance , Humans , Regression Analysis
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