RESUMO
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.
Assuntos
Pneumonia Associada a Assistência à Saúde , Humanos , Pneumonia Associada a Assistência à Saúde/diagnóstico , Pneumonia Associada a Assistência à Saúde/microbiologia , Testes Diagnósticos de Rotina/métodosRESUMO
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.
Assuntos
Síndrome de Churg-Strauss , Granulomatose com Poliangiite , Adolescente , Humanos , Criança , Granulomatose com Poliangiite/tratamento farmacológico , Síndrome de Churg-Strauss/tratamento farmacológico , Anticorpos Monoclonais Humanizados/uso terapêuticoRESUMO
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.
Assuntos
Infecção Hospitalar/microbiologia , Enterococcus faecium/genética , Enterococcus faecium/patogenicidade , Genoma Bacteriano , Plasmídeos/genética , Antibacterianos/farmacologia , Elementos de DNA Transponíveis/genética , Enterococcus faecium/efeitos dos fármacos , Transferência Genética Horizontal , Genômica , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Bactérias Gram-Positivas/transmissão , Hospitais , Humanos , Filogenia , Análise de Sequência de DNA , Sequenciamento Completo do GenomaRESUMO
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.
Assuntos
Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/isolamento & purificação , Águas Residuárias/microbiologia , Microbiologia da Água , China , Infecção Hospitalar , Bases de Dados de Ácidos Nucleicos , Desinfecção das Mãos , Humanos , Unidades de Terapia Intensiva , Infecções por Klebsiella , Sequenciamento Completo do GenomaRESUMO
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.
RESUMO
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.
Assuntos
Bacteriemia/microbiologia , Infecções por Escherichia coli/microbiologia , Escherichia coli/classificação , Escherichia coli/genética , Infecções Urinárias/complicações , Idoso de 80 Anos ou mais , Escherichia coli/isolamento & purificação , Escherichia coli/patogenicidade , Proteínas de Escherichia coli/genética , Feminino , Genoma Bacteriano , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Tipagem de Sequências Multilocus , Polimorfismo de Nucleotídeo Único , Fatores de Virulência/genéticaAssuntos
Antibacterianos/efeitos adversos , Cefalosporinas/efeitos adversos , Síndromes Neurotóxicas/etiologia , Osteomielite/tratamento farmacológico , Infecções por Pseudomonas/tratamento farmacológico , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/complicações , Injúria Renal Aguda/fisiopatologia , Idoso , Antibacterianos/administração & dosagem , Cefepima , Cefalosporinas/administração & dosagem , Feminino , Taxa de Filtração Glomerular , Humanos , Síndromes Neurotóxicas/fisiopatologia , Osteomielite/microbiologia , Infecções por Pseudomonas/microbiologia , Respiração ArtificialRESUMO
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)).
Assuntos
Galinhas , Patos , Virus da Influenza A Subtipo H5N1/patogenicidade , Influenza Aviária/fisiopatologia , Doença de Newcastle/fisiopatologia , Vírus da Doença de Newcastle/patogenicidade , Perus , Animais , Virus da Influenza A Subtipo H5N1/genética , Influenza Aviária/mortalidade , Dose Letal Mediana , Doença de Newcastle/mortalidade , Vírus da Doença de Newcastle/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Especificidade da Espécie , Virulência , Eliminação de Partículas Virais/fisiologiaRESUMO
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.
Assuntos
Campylobacter/isolamento & purificação , Portador Sadio/veterinária , Escherichia coli O157/isolamento & purificação , Contaminação de Alimentos , Carne/microbiologia , Salmonella/isolamento & purificação , Yersinia enterocolitica/isolamento & purificação , Matadouros , Animais , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Bovinos , Fezes/microbiologia , Prevalência , Ovinos , Suínos , Reino Unido/epidemiologia , Zoonoses/microbiologiaRESUMO
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.
Assuntos
Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Síndromes Neurotóxicas/etiologia , Compostos Organometálicos/toxicidade , Estresse Psicológico/complicações , Animais , Peso Corporal/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Química Encefálica/efeitos dos fármacos , Corticosterona/sangue , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Glutationa/metabolismo , Injeções Intramusculares , Nefropatias/induzido quimicamente , Locomoção/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Força Muscular/efeitos dos fármacos , Síndromes Neurotóxicas/complicações , Síndromes Neurotóxicas/metabolismo , Síndromes Neurotóxicas/fisiopatologia , Neurotransmissores/metabolismo , Compostos Organometálicos/administração & dosagem , Compostos Organometálicos/farmacocinética , Ratos , Ratos Sprague-Dawley , Estresse Psicológico/metabolismo , Estresse Psicológico/fisiopatologia , Fatores de Tempo , Distribuição TecidualRESUMO
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.
Assuntos
Surtos de Doenças/veterinária , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/epidemiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Animais , Aves/virologia , Influenza Aviária/virologia , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Sensibilidade e Especificidade , Fatores de TempoRESUMO
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.
Assuntos
Matadouros , Animais Domésticos/microbiologia , Yersiniose/microbiologia , Yersinia enterocolitica/classificação , Animais , Bovinos/microbiologia , Doenças dos Bovinos/microbiologia , Humanos , Ovinos/microbiologia , Doenças dos Ovinos/microbiologia , Suínos/microbiologia , Doenças dos Suínos/microbiologia , Yersiniose/veterinária , Yersinia enterocolitica/patogenicidade , Yersinia enterocolitica/fisiologiaRESUMO
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.
Assuntos
Nutrição Enteral , Eritromicina/uso terapêutico , Fármacos Gastrointestinais/uso terapêutico , Intubação Gastrointestinal/métodos , Estado Terminal , Método Duplo-Cego , Feminino , Humanos , Infusões Intravenosas , Masculino , Pessoa de Meia-IdadeRESUMO
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.
Assuntos
Consumo de Bebidas Alcoólicas/psicologia , Emoções , Enquadramento Psicológico , Adolescente , Adulto , Transtornos Relacionados ao Uso de Álcool/psicologia , Análise de Variância , Atitude , Tomada de Decisões , Feminino , Humanos , Masculino , Assunção de Riscos , EstudantesRESUMO
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.
Assuntos
Proteínas de Bactérias/genética , Infecções por Escherichia coli/microbiologia , Escherichia coli O157/genética , Proteínas de Escherichia coli , Proteínas , Adesinas Bacterianas/genética , Animais , Toxinas Bacterianas/genética , Bovinos , Surtos de Doenças , Enterócitos , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/veterinária , Escherichia coli O157/isolamento & purificação , Células HeLa , Humanos , Interleucina-6 , Fator Inibidor de Leucemia , Chaperonas Moleculares/genética , Serina Endopeptidases/genética , Toxina Shiga I/genética , Toxina Shiga II/genéticaRESUMO
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.
Assuntos
Estimulantes do Sistema Nervoso Central/urina , Alucinógenos/urina , Drogas Ilícitas/urina , Imunoensaio/métodos , N-Metil-3,4-Metilenodioxianfetamina/urina , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Alucinógenos/química , Alucinógenos/toxicidade , Humanos , Drogas Ilícitas/química , Drogas Ilícitas/toxicidade , N-Metil-3,4-Metilenodioxianfetamina/química , N-Metil-3,4-Metilenodioxianfetamina/toxicidade , Sensibilidade e Especificidade , Detecção do Abuso de Substâncias/métodosRESUMO
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).
Assuntos
Ansiolíticos/metabolismo , Escherichia coli/enzimologia , Lorazepam/metabolismo , Oxazepam/metabolismo , Temazepam/metabolismo , Ansiolíticos/farmacocinética , Medicina Legal/métodos , Glucuronidase/metabolismo , Glucuronídeos/análise , Glucuronídeos/química , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Imunoensaio , Lorazepam/farmacocinética , Oxazepam/farmacocinética , Temazepam/farmacocinética , Temperatura , UrináliseRESUMO
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.
Assuntos
Ansiolíticos/sangue , Ansiolíticos/urina , Flunitrazepam/análogos & derivados , Flunitrazepam/sangue , Flunitrazepam/urina , Imunoensaio/normas , Administração Oral , Adulto , Ansiolíticos/metabolismo , Feminino , Flunitrazepam/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Sensibilidade e Especificidade , Detecção do Abuso de SubstânciasRESUMO
Several studies suggest that exposure to 50 Hz magnetic fields may promote chemically induced breast cancer in rats. Groups of 100 female Sprague-Dawley rats were initiated with four weekly 5 mg gavage doses of 7,12-dimethylbenz[a]anthracene (DMBA) starting at 50 days of age. After the first weekly DMBA administration, exposure to ambient fields (sham exposed), 50 Hz magnetic fields at either 1 or 5 G field intensity or 60 Hz fields at 1 G for 18.5 h/day, 7 days/week was initiated. Exposure continued for 13 weeks. A vehicle control group without DMBA was included. In a second study, using lower doses of DMBA, groups of 100 female Sprague-Dawley rats were initiated with four weekly doses of 2 mg of DMBA starting at 50 days of age followed, after the first weekly DMBA administration, by exposure to ambient fields (sham exposed) or 50 Hz magnetic fields at either 1 or 5 G field intensity for 18.5 h/day, 7 days/week for 13 weeks. Rats were weighed and palpated weekly for the presence of tumors. There was no effect of magnetic field exposure on body weight gains or on the time of appearance of mammary tumors in either study. At the end of 13 weeks, the animals were killed and the mammary tumors counted and measured. Mammary gland masses found grossly were examined histologically. In the first 13 week study, the mammary gland carcinoma incidences were 92, 86, 96 and 96% for the DMBA controls, 1 G, 50 Hz, 5 G, 50 Hz and 1 G, 60 Hz groups, respectively. The total numbers of carcinomas were 691, 528 (P < 0. 05, decrease), 561 and 692 for the DMBA controls, 1 G, 50 Hz, 5 G, 50 Hz and 1 G, 60 Hz groups, respectively. In study 2, the mammary gland carcinoma incidences were 43, 48 and 38% for the DMBA controls, 1 G, 50 Hz and 5 G, 50 Hz groups, respectively. The total numbers of carcinomas were 102, 90 and 79 for the DMBA controls, 1 G, 50 Hz and 5 G, 50 Hz groups, respectively. There was no effect of magnetic field exposure on tumor size either by in-life palpation or by measurement at necropsy in either study. There was no evidence that 50 or 60 Hz magnetic fields promoted breast cancer in these studies in female rats. These studies do not support the hypothesis that magnetic field exposure promotes breast cancer in this DMBA rat model.