Neonatal sepsis caused by Streptococcus agalactiae group B streptococcus (GBS) is a life-threatening condition, which is preventable if colonized mothers are identified and given antibiotic ...prophylaxis during labour. Conventional culture is time consuming and unreliable, and many available non-culture diagnostics are too complex to implement routinely at point of care. Loop-mediated isothermal amplification (LAMP) is a method that, enables the rapid and specific detection of target nucleic acid sequences in clinical materials without the requirement for extensive sample preparation.
A prototype LAMP assay targeting GBS sip gene is described.
The assay was 100 % specific for GBS, with a limit of detection of 14 genome copies per reaction. The clinical utility of the LAMP assay for rapid direct molecular detection of GBS was determined by testing a total of 157 vaginal swabs with minimal sample processing using a rapid lysis solution. Compared to a reference quantitative real-time PCR assay, the direct LAMP protocol had a sensitivity and specificity of 95.4 and 100 %, respectively, with positive and negative predictive values of 100 and 98.3 %, respectively. Positive and negative likelihood ratios were infinity and 0.05, respectively. The direct LAMP method required a mean time of 45 min from the receipt of a swab to generation of a confirmed result, compared to 2 h 30 min for the reference quantitative real-time PCR test.
The direct LAMP protocol described is easy to perform, facilitating rapid and accurate detection of GBS in vaginal swabs. This test has a potential for use at point of care.
Scholars of the American Revolution have often portrayed Early Modern North Americans as being characterized by unwavering negative biases toward those perceived as the “other.” However, such ...black-and-white interpretations do not account for the scores of North Americans whose ideas were periodically contested and transformed during the American Revolution. In glaring contrast to previous interpretations of Early Modern prejudices, the American rebel invasion of Quebec in 1775-76 unveils the extent to which individual convictions were capable of fluctuation over time. During the invasion, groups of peoples who had feuded for generations - i.e. Protestant British colonists on the one hand and the indigenous Wabanaki and Catholic French on the other-collaborated with and even praised one another for months. However, such amicable relations did not last, and as soon as the tide turned against the invading rebels, local-invader relations collapsed, and old prejudicial beliefs reasserted themselves. In short, this study into the invasion of Quebec shows that Early Modern North American prejudices were complex and susceptible to change.
Abstract Although the introduction of automated blood culture systems has dramatically reduced laboratory personnel bench time, 48 to 72 h is still required for the identification of pathogens such ...as methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) and the accurate determination of antimicrobial sensitivities for prompt optimal patient therapy and infection control initiatives. The following 4 DNA blood culture extraction methods were compared: (a) organic, (b) differential centrifugation and lysis, (c) alkali wash/lysis, and (d) Qiagen lysis/filtration (QIAGEN, West Sussex, UK). The benzyl alcohol extraction method (a) was found to be the most optimal method having a reasonable extraction time of 1.8 h and 100% correlation with the “gold standard” laboratory culture. A “dual locus” real-time polymerase chain reaction (PCR) targeting the S. aureus -specific thermonuclease nuc gene and the staphylococcal methicillin resistance determinant mecA gene were used as a reliable indicator of the presence of MRSA. In conjunction with the DNA extraction method (a), detection time for MRSA/MSSA isolates from positive blood cultures was dramatically reduced from at least 24 to 48 h to approximately 3 h.
Loop mediated isothermal amplification (LAMP) is an innovative technique which allows the rapid detection of target nucleic acid sequences under isothermal conditions without the need for complex ...instrumentation. The development, systematic optimisation and clinical validation of a LAMP assay targeting the ctrA gene for the rapid detect ion of capsular N. meningitidis is described. Highly specific detection of capsular N. meningitidis type strains and clinical isolates was demonstrated, with no cross reactivity with other Neisseria spp., or with a comprehensive panel of other common human pathogens. The lower limit of detection was determined as 6 ctrA gene copies detectable in 48 minutes, with positive reactions readily identifiable visually via a simple colour change. High copy numbers could be detected in 22 minutes. Clinical Validation was carried out by retrospectively and prospectively analysing a total of 935 clinical specimens from a total of 603 patients. The level of agreement between the ctrA LAMP assay and a confirmatory test result (Culture, MRU PCR, ctrA RT-PCR) for each patient was used to evaluate the performance of LAMP for the detection of capsular N. meningitidis. The overall sensitivity and specificity of the designed ctrA LAMP assay was determined as 94.6% and 99.6% with positive and negative predictive values of 96.4% and 99.5% respectively. The potential utility of a positive ctrA LAMP respiratory specimen result to indicate MD was investigated. The sensitivity and specificity of respiratory• specimens in this regard was 89.3% and 97.7% with positive and negative predictive values of 80.7% and 98.9% respectively. Rapid LAMP testing of non-invasive respiratory specimens has significant potential to accelerate the diagnosis of MD. The LAMP method represents a simple, rapid, sensitive, and highly specific technique for the detection of N. meningitidis, and has the potential to be used as a POC molecular test and in resource poor settings.
This thesis examines the recreational use of a multi-functional resource, the Avon-Heathcote Estuary. The nature
resources suitable for outdoor recreation in the Christchurch
area and the present use ...made of them are explored
through a demand-supply framework. Although exploratory,
the research into recreational use of an estuarine environment
advocates the need for a greater understanding of resource
capabilities and use requirements. To this end, a framework which examines both user and resource is described.
Recreation resources within the study area are identified
and examined with respect to quantity, quality and distribution.
Recreational demand is analysed in terms of measures of
recreationalists' attitudes preferences and activities. The
diversity of functions provided by the Avon-Heathcote Estuary
means that recreation must be considered in relation to other
uses. In view of the expected growth in recreational use of
the Estuary the notion of carrying capacity is introduced.
The capacity concept is discussed within the wider context
of maintaining user satisfaction and conserving the estuarine
environment.
The rapid emergence of multidrug-resistant pathogens worldwide has raised concerns regarding the effectiveness of conventional antibiotics. This can be observed in ESKAPE pathogens, among others, ...whose multiple resistance mechanisms have led to a reduction in effective treatment options. Innovative strategies aimed at mitigating the incidence of antibiotic-resistant pathogens encompass the potential use of biosurfactants. These surface-active agents comprise a group of unique amphiphilic molecules of microbial origin that are capable of interacting with the lipidic components of microorganisms. Biosurfactant interactions with different surfaces can affect their hydrophobic properties and as a result, their ability to alter microorganisms' adhesion abilities and consequent biofilm formation. Unlike synthetic surfactants, biosurfactants present low toxicity and high biodegradability and remain stable under temperature and pH extremes, making them potentially suitable for targeted use in medical and pharmaceutical applications. This review discusses the development of biosurfactants in biomedical and therapeutic uses as antimicrobial and antibiofilm agents, in addition to considering the potential synergistic effect of biosurfactants in combination with antibiotics. Furthermore, the anti-cancer and anti-viral potential of biosurfactants in relation to COVID-19 is also discussed.
The endangered Silver Chub (Macrhybopsis storeriana, Kirtland 1844) is native to North America and primarily riverine, with the only known large‐lake population in Lake Erie. Once a major component ...of the Lake Erie fish community, it declined and became nearly extirpated in the mid‐1900s. Recent collections in western Lake Erie suggest that Silver Chub may be able to recover, but their habitat and distribution are poorly known. A recent work showed an extensive area of western Lake Erie with the potential to support large numbers of Silver Chub, but was based on a geographically limited dataset. We developed a neural network‐based species distribution model for the Silver Chub in western Lake Erie, improved by new synoptic data and using habitat variables resistant to anthropogenic activities. The Potential model predictions were compared with a model that included anthropogenic‐sensitive variables. The Potential model used 10 habitat variables and performed well, explaining > 99% of data variation and had generally low error rates. Predictions indicated that a large area of the waters approximately 2–9 m deep contained Appropriate habitat and the highest abundances should be supported by habitat in a wide arc through the western end of the basin. The model indicated that Appropriate Silver Chub habitat was associated with relatively deep water, near coastal wetlands, where effective fetch is less than average. Disturbance model predictions were similar, but predicted poorer Silver Chub habitat in more areas than that predicted by the Potential model. Our Potential model reveals Appropriate habitat conditions for Silver Chub and its spatial distribution, indicating that extensive areas of western Lake Erie could support Silver Chub. Comparisons with Disturbance model predictions demonstrate that Potential model predictions may be used in conjunction with analyses of degrading conditions in the system to better conserve and manage for this endangered species.
The only Great Lake population of Silver Chub (Macrhybopsis storeriana) is imperiled, and the species is listed as Endangered in parts of Lake Erie. The model developed in this study characterizes best potential Silver Chub habitat and its distribution in Western Lake Erie and compares them with disturbed conditions, supporting conservation of this unique population.
Chemokines play diverse and fundamental roles in the immune system and human disease, which has prompted their structural and functional characterisation. Production of recombinant chemokines that ...are folded and bioactive is vital to their study but is limited by the stringent requirements of a native N-terminus for receptor activation and correct disulphide bonding required to stabilise the chemokine fold. Even when expressed as fusion proteins, overexpression of chemokines in E. coli tends to result in the formation of inclusion bodies, generating the additional steps of solubilisation and refolding. Here we present a novel method for producing soluble chemokines in relatively large amounts via a simple two-step purification procedure with no requirements for refolding. CXCL8 produced by this method has the correct chemokine fold as determined by NMR spectroscopy and in chemotaxis assays was indistinguishable from commercially available chemokines. We believe that this protocol significantly streamlines the generation of recombinant chemokines.
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