Tutorial Topics in Infection for the Combined Infection Training Programme最新文献

{"title":"Molecular Diagnostics","authors":"D. Clark, M. Wilks","doi":"10.1093/oso/9780198801740.003.0018","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0018","url":null,"abstract":"Molecular diagnostics in infection generally relate to the detection and/ or characterization of nucleic acid sequences of infectious agents in clinical samples which are used to provide: ● A laboratory diagnosis. ● A means of monitoring patients at risk of developing disease caused by a particular infection. ● A method to predict through genotypic analysis the susceptibility or resistance to appropriate treatments. ● A measurement of the response to therapy. A few key laboratory techniques underpin the majority of molecular diagnostic tests that are currently used in the field of infection, and include: ● Block-based polymerase chain reaction (PCR). ● Real-time PCR, including quantification. ● Strand displacement amplification. ● Transcription mediated amplification. ● DNA sequencing. These can be commercially sourced, which has the advantage of CE marking, or developed in-house, sometimes referred to as laboratory developed tests (LDTs). Whatever the source, the underlying principles are often the same and rigorous evaluation and validation is required for the adoption of any molecular test in the diagnostic laboratory. The majority of molecular diagnostic tests require the amplification of a specific DNA sequence and its subsequent detection by a variety of means. As such, small sequences of DNA from the infectious agent are amplified from a relatively low copy number in the clinical sample. For example, after thirty to forty cycles of PCR, a single copy of a sequence can theoretically be amplified to over a billion copies. This PCR product, commonly termed amplicon, can provide a template for any further testing with the same PCR test and therefore potentially act as a source for false positive results. Molecular diagnostic laboratories have requirements to keep the different stages of the molecular test separate and minimize the risk of amplicon contamination. Most facilities will have a ‘clean PCR laboratory’ that is used to store the clean reagents such as primers, probes, enzyme mastermixes, and no clinical samples, nucleic extracts, or amplification reactions are ever taken into this environment. Another laboratory is used for the nucleic acid extraction of the clinical samples and this environment is often used to set up the PCR reactions.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132119667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vaccination Schedules","authors":"G. Y. Shin","doi":"10.1093/oso/9780198801740.003.0062","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0062","url":null,"abstract":"The vaccines included in the current UK Immunisation Schedule offer protection against the following pathogens: A. Viruses ● Measles ● Mumps ● Rubella ● Polio ● Human Papilloma Virus (certain serotypes) ● Rotavirus ● Influenza virus (flu A and B) ● Varicella zoster virus (shingles) ● Hepatitis B virus B. Bacteria ● Corynebacterium diphtheriae (Diphtheria) ● Clostridium tetani (Tetanus) ● Bordetella pertussis (Pertussis) ● Haemophilus influenzae type B (Hib) ● Neisseria meningitidis (Meningococcal disease—certain serotypes) ● Streptococcus pneumoniae (Pneumococcal disease—certain serotypes) The UK Immunisation Schedule has evolved over several decades and reflects changes in vaccine development and commercial availability, national and sometimes international disease epidemiology, and the latest expert opinion. It is designed to offer optimal protection against infectious diseases of childhood to infants and children at the most appropriate age. The most up-to-date information about the UK Immunisation Schedule is available on the online version of the Department of Health publication commonly known as the ‘Green Book’: Immunisation Against Infectious Disease Handbook (see Further reading. Various chapters of the online version are updated at regular intervals; thus, it is very important to refer to the online version of the Green Book on the website for current guidance. Changes to the UK Immunisation Schedule are made on the recommendation of the independent Joint Committee on Vaccines and Immunisation (JCVI). Several of the UK Immunisation Schedule vaccines are combined vaccines: ● Measles, mumps, and rubella (MMR). ● Hexavalent diphtheria, tetanus, acellular pertussis, inactivated polio virus, Haemophilus influenza type b, hepatitis B (DTaP/IPV/Hib/HepB). ● Diphtheria, tetanus, acellular pertussis, inactivated polio, and Haemophilus influenzae (DTaP/IPV/Hib). ● Diphtheria, tetanus, acellular pertussis, inactivated polio (DTaP/IPV). ● Tetanus, diphtheria, and inactivated polio (Td/IPV). ● Inactivated influenza vaccine: influenza A H1N1, H3N2, influenza B. ● Live attenuated intranasal influenza vaccine: influenza A H1N1, H3N2, influenza B. In the UK, vaccines against single pathogens covered by the MMR vaccine are not recommended and not available in the National Health Service (NHS). There has been some limited demand for single-target vaccines, e.g. measles, due to misguided and unfounded concerns about the alleged risks of autism following MMR.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130799671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exanthemata","authors":"C. Y. William Tong","doi":"10.1093/oso/9780198801740.003.0047","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0047","url":null,"abstract":"An exanthem (or exanthema) is a widespread skin rash accompanying a disease or fever. It usually occurs in children as part of a common systemic childhood viral infection, but can also occur in adults and can be caused by bacterial infections, toxin or drug reactions. An enanthem (or enanthema) is a rash that occurs in the mucous membrane, typically in the mouth, as the result of the same disease process of an exanthema. Because the presence of a rash is a very striking feature, historically, several of the commonly seen febrile illnesses associated with rash have been recognized and named in numerical order. There are various things to look out for when assessing a patient with exanthema. These can include the type and evolution of the rash, as well as contact, vaccine, drug, sexual, and travel history. ● Type of rash: ■ maculopapular; ■ vesicular; ■ petechial. ● Evolution of the rash: ■ prodrome, if any; ■ date of onset of fever; ■ date of onset of the rash; ■ progression of the rash (e.g. starting location and spread); ■ other associated features (e.g. conjunctivitis, lymphadenopathy, hepatosplenomegaly). ● Contact history: ■ history of contact with anyone with febrile or rash illness; ■ recent local outbreaks, if any; ■ contact with other vulnerable individuals before and after onset of illness (for infection control purposes). ● Vaccine history: ■ recent history of any vaccination; ■ previous vaccination history (particularly MMR and varicella); ■ timing of these vaccines and number of doses. ● Drug history: ■ including antibiotics given for the illness. ● Sexual history: ■ always consider this in any patient. ● Recent travel history: ■ record timing and location; ■ history of insect bites. A good description of the rash can help in narrowing down the possible causes. The commonly seen rashes can be maculopapular, vesicular, or petechial. Maculopapular rash can be further categorized into subtypes. These include: ● morbilliform—a red rash which is measles-like, two to ten mm in diameter, and which merge to form confluent patches.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124130705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-Exposure Prophylaxis","authors":"C. Tong","doi":"10.1093/oso/9780198801740.003.0064","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0064","url":null,"abstract":"Post-exposure prophylaxis (PEP) is a treatment administered to an individual to prevent the development of infection or reduce the severity of illness after a potential or documented exposure to a microorganism. This may primarily be for the protection of the exposed individual concern, or in the case of a pregnant woman, for protecting the foetus in utero. PEP may also be useful in public health to reduce the risk of secondary spread of infection. A good history is required in order to make a proper assessment of the risk. The following questions should be asked: A. Which infection is suspected and is the source infectious? It is straight forward if the diagnosis of the source of exposure is already known, e.g. known HIV, established diagnosis of tuberculosis. However, in many cases, the diagnosis of the source may not be certain, e.g. needle stick injury involving a needle of unknown origin, bitten by a stray dog, exposed to a child with a non-specific rash. In such cases, a risk assessment is required to assess the likelihood that the source may be infectious. Knowledge of local epidemiology or recent outbreaks in a particular locality may help in such risk assessment. B. What is the nature of the exposure? Knowledge of the mode of transmission of a microorganism is important to establish if there is any risk of transmission through the exposure In the case of mother-to-child transmission, PEP to the neonate born to a mother with an infection is effective if the mode of transmission is predominately perinatal, e.g. hepatitis B. If the mode of transmission is transplacental, it is too late to administer PEP to the baby after delivery. Instead, the expected mother should be given prophylaxis during pregnancy to prevent infection, e.g. chicken pox, or given antivirals to reduce infectivity, e.g. maternal hepatitis B with a high viral load when transplacental infection may occur. In HIV, where transmission can occur both transplacentally and perinatally, antiretroviral therapy (ART) needs to be given during pregnancy and often during labour as well as to the baby after birth.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126506223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Upper and Lower Respiratory Tract Infections","authors":"Simon Tiber","doi":"10.1093/oso/9780198801740.003.0040","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0040","url":null,"abstract":"Pharyngitis is common with incidence peaking from autumn to spring. Respiratory viruses are most commonly implicated, and are generally self-limiting conditions not requiring diagnostic workup or treatment. Bacterial pharyngitis is less common, is spread by droplets or direct transmission, and Streptococcus pyogenes (Group A strep, or GAS) is the most frequent cause. Haemophilus influenzae, Mycoplasma pneumoniae, and Neisseria gonorrhoeae are less frequent causes. Rapid antigen detection tests make the point-of-care assessment of GAS pharyngitis possible, although a negative test does not exclude infection. No method can distinguish oropharyngeal colonization from actual infection, but culture can obtain antibiotic susceptibility testing. Suspicion of infection with Neisseria gonorrhoeae, Bordetella pertussis, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, or Corynebacterium diptheriae should be communicated to the laboratory so that the appropriate culture media is utilized. The Centor criteria provide a clinical predictive score that can give the likelihood a sore throat is due to a bacterial infection with the following: the presence of tonsillar exudate, tender anterior cervical adenopathy, fever over 38°C, and absence of cough. If three or four of these criteria are met, the positive predictive value is 40% to 60%. The absence of three or four of the Centor criteria has a relatively high negative predictive value of 80%, and may be use to evaluate whether antibiotics can be withheld or deferred. Oral penicillin or macrolide are used to treat streptococcal pharyngitis. Treatment may reduce severity, duration, transmission, and risk of post-infectious sequelae like rheumatic heart disease and post-streptococcal glomerulonephritis. Other complications include scarlet fever, streptococcal toxic shock syndrome, and quinsy. Otitis media, is frequent in the young children, possibly due to a short and horizontal Eustachian tube. Purulent material buils up leading to a bulging, red tympanic membrane which may rupture and discharge. Intense local pain and fevers may occur. Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae are frequently implicated. Frequently there are no sequelae, although complications include hearing impairment, and less common are mastoiditis, bacteraemia, and meningitis. Diagnosis is clinical based on presentation and otoscopic examination. Microbiological diagnosis is possible through culture of exuate on swab or following tympanocentesis.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"22 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120998395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}