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

{"title":"Vaccination of Specific Groups","authors":"G. Y. Shin","doi":"10.1093/oso/9780198801740.003.0063","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0063","url":null,"abstract":"While the UK immunisation schedule is a national immunisation policy for the general population, several groups of patients and persons require a different approach to be taken. For example, some groups of patients cannot safely receive certain vaccine because they may be allergic (anaphylaxis) to some vaccine components and some patients cannot receive, e.g. live attenuated vaccines because they are severely immunocompromised. Other patients require additional vaccines to protect them from vaccine preventable diseases because they are immunocompromised in some way, e.g. asplenia. The following groups require special consideration: ● Pregnant women; ● Severely immunocompromised patients; ● Asplenic patients or those with dysfunctional spleens; ● Severe allergy to vaccine components; ● healthcare workers (HCWs); ● Patients with certain chronic medical conditions; ● Morbid obesity; and ● Persons travelling abroad, especially to developing countries. In general, giving vaccines to pregnant women is not recommended due to the potential risk of medicines and vaccines harming the foetus. Specifically, live attenuated vaccines should not be given to pregnant women. It is relatively safer to give inactivated/killed vaccines to pregnant women, but most vaccines can and should be postponed until after delivery. However, in the UK it is recommended that pregnant women receive two particular vaccines during pregnancy in order to protect the mother and foetus from avoidable harm. These are the inactivated influenza vaccine and a vaccine against Bordetella pertussis infection. For these two vaccines, the benefits of vaccination for the pregnant women and the foetus or newborn baby outweigh any theoretical risks of harm. Severely immunocompromised patients should not receive live attenuated vaccines due to a risk of uncontrolled viral replication resulting in clinical disease. Patients who are considered to be severely immunocompromised include: ● Severe primary immunodeficiency, e.g. severe combined immunodeficiency; ● Patients receiving cancer chemotherapy and those within six months of completing chemotherapy; ● Patients who have received a solid organ transplant and are on immunosuppressive therapy; ● Patients who have received a bone marrow transplant until twelve months after all immunosuppressive therapy has stopped; and ● Patients receiving high-dose systemic corticosteroids until at least three months after treatment ends.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"214 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":"126744500","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":"Pregnancy-Associated Infections","authors":"A. Riddell, Mick Millar","doi":"10.1093/oso/9780198801740.003.0048","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0048","url":null,"abstract":"An important consideration in pregnancy is the relationship between infection in the mother and the developing foetus. Infections can indirectly impact the foetus through effects on the mother, for example, maternal urinary tract infection is associated with preterm birth, or can infect the foetus. Routes of infection can be ascending from the birth canal through the cervical os, transplacentally, or rarely, contiguously. The effect on the mother is also important: pregnancy is considered an immunosuppressive state and the growing foetus causes significant mechanical and physiological changes. Although the first trimester is the key developmental phase for the growing foetus, during the third trimester the mother is more susceptible to severe respiratory infection and some viral infections such as varicella zoster virus (VZV), due to the mechanical changes produced by the growing foetus. There is a paucity of evidence supporting the safety of drugs in pregnancy. Use of any medicinal drug in pregnancy, including antibiotics, requires good reasons. The optimum choice of antibiotics depends on the trimester of the pregnancy. In general, beta-lactams are safe and tetracyclines should be avoided throughout pregnancy. Nitrofurantoin is safe until after thirty-five weeks gestation and trimethoprim should be avoided in the first trimester but is safe otherwise (perhaps with folic acid supplementation if < 20 weeks). Specific patterns of colonization and infection of the genitourinary tract can be associated with an increased risk of an adverse pregnancy outcome, particularly preterm birth. Sexually transmitted diseases such as gonorrhoea and chlamydia are associated with an increased risk of spontaneous preterm birth, which may extend to infection in the pre-conception period. Bacterial vaginosis is an abnormal pattern of vaginal colonization and is also linked with an increased risk of preterm birth. The US Center for Disease Control recommends screening all pregnant women for chlamydia, gonorrhoea, syphilis, HIV, and hepatitis B, symptomatic women for trichomonas and genital herpes, women considered at high risk of preterm birth for bacterial vaginosis, and women at high risk of blood-borne virus infection for hepatitis C. Treatment is administered to reduce the risk of an adverse pregnancy outcome (syphilis, gonorrhoea, chlamydia, trichomonas, and bacterial vaginosis) or to prevent transmission to the infant (herpes, HIV, hepatitis B, and C).","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":"127523926","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":"Zoonotic Infections","authors":"M. G. Sanz, C. N. Fhogartaigh","doi":"10.1093/oso/9780198801740.003.0046","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0046","url":null,"abstract":"The term zoonosis comes from the Greek: ζῷον (zoon) ‘animal’ and νόσος (nosos) ‘sickness’, and means an infection transmissible from animals to humans. Infected animals can be symptomatic or asymptomatic, and humans usually become accidental hosts through close contact with the reservoir animal. Six out of ten infections in humans globally are spread from animals, and 75% of emerging infections are zoonotic. Some occur worldwide e.g. E. coli O157:H7, whereas some are more restricted geographically, e.g. Ebola virus. The highest burden is in developing countries. There are various classifications of zoonoses. ● Causative pathogen: bacterial (anthrax, non-typhoidal Salmonelloses); viral (rabies, Yellow Fever, hantaviruses); parasitic (hookworm, Giardia, toxoplasmosis); fungal (dermatophytes, histoplasmosis); or prion (new-variant Creutzfeldt-Jakob disease). ● Mode of transmission (see Section 35.3 and Table 35.1 below) ● Distribution: endemic zoonoses are continually present in a population (e.g. leptospirosis, brucellosis); epidemic zoonoses occur intermittently (e.g. anthrax, Rift Valley Fever); emerging zoonoses are new infections, or existing infections that are increasing in incidence or geographical range (e.g. Nipah virus, Middle East Respiratory Syndrome coronavirus). ● Direct contact: infectious particles are present on an infected animal, in its body fluids, and in its excreta. Q fever, caused by Coxiella burnetii, and brucellosis may be acquired by direct contact with infected animals, particularly during parturition; cat-scratch disease caused by Bartonella henselae, and Pasteurella spp. may be acquired by bites or scratches from cats, and rabies from canine bites. Many zoonoses are also transmitted via indirect animal contact through exposure to soil or water contaminated by infectious material, e.g. leptospirosis may be acquired when water contaminated with infected rats’ urine comes into contact with broken skin or mucous membranes. ● Ingestion: infection occurs by ingesting contaminated food or water, e.g. unpasteurized milk, poorly processed or undercooked meat, or by eating/ drinking after handling animals without handwashing. Listeria, bovine tuberculosis, and brucellosis may be transmitted by unpasteurized milk and dairy produce; Hepatitis E through processed pork, and Ebola and Marburg through bushmeat. ● Vector-borne: infection is transmitted through a biting arthropod vector. Examples include West Nile Virus and Japanese encephalitis from mosquitoes, Lyme disease, tick-borne encephalitis, and Rocky Mountain Spotted Fever from ticks, and Rickettsia typhi from rat fleas.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"65 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":"127493086","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":"Antimicrobial Stewardship","authors":"S. Ameen, C. NicFhogartaigh","doi":"10.1093/oso/9780198801740.003.0028","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0028","url":null,"abstract":"Antimicrobial stewardship (AMS) is a healthcare- system- wide approach to promoting and monitoring the judicious use of antimicrobials (including antibiotics) to preserve their future effectiveness and optimize outcomes for patients. Put simply, it is using the right antibiotic, at the right dose, via the right route, at the right time, for the right duration (Centres for Disease Control, 2010). Antimicrobial resistance (AMR) is a serious and growing global public health concern. Antibiotics are a unique class of drug as their use in individual patients may have an impact on others through the spread of resistant organisms. Antibiotics are essential for saving lives in conditions such as sepsis, and without effective antibiotics even minor operations could be life-threatening due to the risk of resistant infections. Across Europe approximately 25,000 people die each year as a result of hospital infections caused by resistant bacteria, and others have more prolonged and complicated illness. By 2050, AMR is predicted to be one of the major causes of death worldwide. Protecting the use of currently available antibiotics is crucial as discovery of new antimicrobials has stalled. Studies consistently demonstrate that 30–50% of antimicrobial prescriptions are unnecessary or inappropriate. Figure 18.1 shows some of the reasons behind this. As well as driving increasing resistance, unnecessary prescribing leads to unwanted adverse effects, including avoidable drug reactions and interactions, Clostridium difficile-associated diarrhoea, and healthcare-associated infections with resistant micro-organisms, all of which are associated with adverse clinical outcomes, including increased length of hospital stay and mortality, with increased cost to healthcare systems. Prudent use of antibiotics improves patient care and clinical outcomes, reduces the spread of antimicrobial resistance, and saves money. There are a number of global and national guidelines outlining what a robust AMS programme should consist of (see Further reading and useful resources), including: ● Infectious Diseases Society of America (IDSA): Guidelines for Developing an Institutional Programme to Enhance Antimicrobial Stewardship. ● National Institute for Health and Care Excellence (NICE): Antimicrobial Stewardship: Systems and Processes for Effective Antimicrobial Medicine Use [NG15]. ● Department of Health (DoH): Start Smart Then Focus, updated 2015. ● DoH: UK 5- Year Antimicrobial Resistance Strategy 2013 to 2018.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"612 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":"116397635","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":"Infections in Neonates and Young Children","authors":"M. Millar, S. Kempley","doi":"10.1093/oso/9780198801740.003.0049","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0049","url":null,"abstract":"This chapter covers infections in neonates and young children. In this chapter the term ‘young children’ indicates children under two years of age. For information on congenital infections interested readers are referred to Chapter 37. Early neonatal infection is variably defined as infection presenting up to a week after birth, but most infections present in the first seventy-two hours. Microbial invasion of the chorio-amniotic membranes or uterine cavity occur in a significant proportion of pregnancies before rupture of membranes (> 50% with preterm birth before thirty weeks gestation, 10% with term delivery), and in the majority of those with prolonged rupture of membranes (> 24 hours). It is likely that the majority of cases of early sepsis arise through ascending infection of the uterus (through the cervical canal). Ascending infection may be important in the pathogenesis of preterm birth and is more common in infants born preterm. Group B Streptococci (GBS) (Streptococcus agalactiae) and Escherichia coli are the most common agents of early neonatal infection. Infection with Listeria monocytogenes probably arises following ingestion of contaminated food by the mother, blood stream infection, and transplacental spread. Early infection with GBS usually presents with respiratory distress and can be difficult to differentiate from respiratory distress associated with other causes, particularly prematurity. The incidence of GBS blood stream infection in England and Wales has been 0.3–0.45/ 1000 live births over the last five years. Maternal genital herpes simplex infection can spread to the newborn infant and cause a wide range of serious clinical presentations, with skin, systemic, and central nervous system involvement. Maternal infection with Neisseria gonorrhoea or Chlamydia trachomatis can also infect the infant. Either can cause conjunctivitis which can sometimes be of sufficient severity to cause substantial damage to the eyes. Gonococcal conjunctivitis usually presents in the first few days of life. Infection with Chlamydia trachomatis (conjunctivitis or pneumonitis) tends to present later. Traditionally, penicillin and an aminoglycoside have been used to treat infants with suspected early sepsis (to cover GBS and Escherichia coli). Newborn infants are often empirically treated because it can be difficult to differentiate early bacterial sepsis from respiratory distress associated with prematurity, and death may ensue rapidly if the infection is not treated.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"194 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":"114223629","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":"Fungal Diagnostics","authors":"S. Seaton, R. Manuel","doi":"10.1093/oso/9780198801740.003.0017","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0017","url":null,"abstract":"The field of fungal diagnostics encompasses tests that are performed to help diagnose fungal disease, guide its management, and or monitor the effectiveness of its treatment. For some superficial skin and yeast infections, a clinical examination of the patient combined with microscopic examination of the sample may be sufficient to determine that fungal disease is present, even if the specific fungal pathogen is not identified. For deep- seated and systemic infections, a combination of diagnostic tests may be required in order to obtain a definitive diagnosis. These include microscopy to detect fungal elements, culture, detection of circulating antigens and antibodies, and molecular tests. More recently, molecular and proteomic approaches have increasingly dominated the conventional identification of pathogenic yeasts and, to some extent, filamentous fungi, since traditional methods are time consuming. More importantly, conventional methodologies have failed to identify common organisms that display uncharacteristic profiles, or fungal pathogens that are rarely encountered. The ‘gold standard’ for the definitive diagnosis of fungal disease is histology or culture of the fungal pathogen from a clinical specimen. A specimen will routinely be inoculated onto several different types of media, and then incubated at specific conditions and temperatures for up to twenty-one days. Media plates will be examined periodically for growth, and staff will try to identify the fungus using both macroscopic and microscopic morphologies. The few biochemical tests available, e.g. the urease test, can be helpful in identification, most often for yeast species. Microscopy of fungal isolates, histopathological examination of tissue, and fungal specific stains play fundamental roles in the diagnosis of infection for the variety of fungi that cause disease. The most common stain for identifying fungal elements from a cultured isolate is lactophenol fuschin/aniline blue stain. Figure 10.1 depicts the fruiting body (conidiophore) of Aspergillus fumigatus species complex, the most prevalent fungal species responsible for invasive aspergillosis (IA) in severely immunocompromised individuals. Figure 10.2 illustrates the phenotype of a three-day old colony. Serological tests are beneficial when non-culture based diagnosis of fungal disease is required. Complement fixation is predominantly used to diagnose endemic mycoses, e.g. coccidioidomycosis, blastomycosis, and histoplasmosis.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"39 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":"124835582","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":"Key Communicable Diseases of Public Health Significance and UK Legislation","authors":"M. Basarab","doi":"10.1093/oso/9780198801740.003.0023","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0023","url":null,"abstract":"Timely reporting to public health authorities of certain infections which are transmissible between individuals and/or are likely to have been acquired from a contaminated source is essential to prompt immediate action to reduce further spread. In England, Health Protection Teams (HPTs) effect health protection actions at local level. They act as the ‘proper officer’ carrying out the function of receiving notifications in relation to the statutory regulations for both attending registered medical practitioners and diagnostic laboratories (see Section 14.6 and Section 14.7). Notification to public health authorities is a legal requirement. It is critical to the control and prevention of outbreaks of communicable diseases and is an integral part of wider local and national infection surveillance. Clinical recognition is the first step and public health authorities should be notified on clinical suspicion before obtaining laboratory test results to look for causative pathogens. As soon as a notification has been made, public health risk assessment and appropriate measures can be initiated. These may include preventing others being exposed to cases or a possible source of contamination, offering chemoprophylaxis, vaccination, education, and closing down of premises. The intervention will depend on the clinical syndrome, the confirmed or presumed infectious agent involved, and any further supporting or refuting diagnostic laboratory results. Time is of the essence; there should be no delay in notifications. Health protection legislation is set out in the Health Protection (Notification) Regulations 2010. It requires both registered medical practitioners (RMPs) and laboratories to notify cases of infection or contamination that could present a significant risk to human health, on the basis of clinical suspicion or laboratory confirmation. The medical doctor (and no other healthcare professional) attending the patient with possible or probable or confirmed infection is responsible for notification to the public health authorities.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"5 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":"123139971","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":"Sterilization and Decontamination","authors":"Sylvia Chegra, M. Cummins","doi":"10.1093/oso/9780198801740.003.0030","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0030","url":null,"abstract":"Decontamination is the combination of processes (including cleaning, disinfection, and sterilization) used to make a re-usable item safe for medical use. It is important to have an understanding of the meaning of each of these terms as well as their application. Cleaning: a process to remove infectious agents and organic matter. The effectiveness of reducing microbial contamination will vary dependent upon the efficacy of the cleaning process and the initial bio- burden. It is important to note that this process does not necessarily destroy infectious agents and is a pre-requisite to disinfection and/ or sterilization. Disinfection: a process to reduce the number of viable infectious agents and which is commonly achieved either chemically or thermally. For some infectious agents (such as certain viruses and bacterial spores) it is not an effective method for inactivation and will not achieve the same level of reduction as is achieved through terminal sterilization. Sterilization: a process which renders an object free from viable infectious agents, including viruses and bacterial spores. Sterilization is achieved most commonly using a prescribed ratio of time, temperature, and steam or chemicals such as hydrogen peroxide, gas plasma, or ethylene oxide. The effective decontamination of re- usable medical devices is essential in reducing the risk of transmission of infectious agents with the chosen method of decontamination being detailed in the manufacturer’s decontamination guidance or instructions for use (IFU), supplied when a medical device is purchased. The guidance will reflect the validation that was carried out prior to the release of the product by accredited laboratories to ensure that the cleaning guidance is both effective and will not adversely affect the device. The aim of the decontamination process is to: 1. Reduce or completely remove microbial contamination to such a level that it is both safe to handle for staff and safe for further use on patients. 2. Ensure that there is no toxic chemical residue on the surface of the device that could cause adverse reactions when used on a patient. 3. Ensure that the decontamination process is compatible with the device and that it does not damage the device through the use of chemicals that can have an adverse effect on the device or by exposing it to either heat or water, which may cause damage.","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":"130787017","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":"Multisystem Infections","authors":"M. Melzer","doi":"10.1093/oso/9780198801740.003.0036","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0036","url":null,"abstract":"Many bacterial infections can cause multisystem or metastatic infection, commonly through haematogenous spread, with preferred sites or tropism depending upon specific organism. For example, Staphylococcus aureus is a well-recognized cause of infective endocarditis, joint infection, and vertebral osteomyelitis. Klebsiella pneumoniae can cause endogenous endophthalmitis in association with a pyogenic liver abscess, a syndrome well described in East Asia. Streptococcus pneumoniae typically causes lower respiratory tract infections or bacterial meningitis. The combination of meningitis, pneumonia, and endocarditis is called ‘Austrian syndrome’ and is strongly associated with hyposplenism or alcohol abuse. Other examples of bacteria that disseminate and cause multisystem infection are covered elsewhere. C. albicans or non-albicans species in the blood can metastasize to the eye (causing chorioretinitis or endophthalmitis) or to the heart (causing infective endocarditis). The primary sites of infection are commonly the GI tract or intravascular catheters, and high-risk groups include patients who have recently undergone abdominal surgery, received multiple courses of intravenous antibiotics, and are receiving total parenteral nutrition. Empirical treatment is with either IV liposomal amphotericin or an echinocandin before stepping down to an oral azole, commonly fluconazole at a dose of 400mg od. Because of the risk of metastatic spread, minimum duration is normally two weeks after the first negative blood culture. Cryptococcosis is caused by one of two species: Cryptococcus neoformans or Cryptococcus gattii. Unlike C. neoformans, C. gattii can cause infection in immunocompetent people. The clinical syndrome, Cryptococcosis, is an opportunistic infection for AIDS, but other conditions that predispose to infection are lymphoma, sarcoidosis, liver cirrhosis, and corticosteroids. Following inhalation, cryptococci can disseminate to the cerebrospinal fluid (CSF) and cause meningitis. Occasionally, Cryptococcoma—umbilicated papules on the skin— can occur. Symptoms are often subacute and include fever and dry cough. Following dissemination to the CSF, headache and confusion can occur. Diagnosis is based upon detection of capsular antigen by latex particle agglutination or culture, typically from blood or CSF. For meningitis, treatment consists of three phases. The induction phase is two weeks of IV liposomal amphotericin and flucytosine, followed by consolidation with eight weeks of oral fluconazole 800mg once daily, then finally secondary prophylaxis, 200mg orally once daily.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"272 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":"134069720","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":"The Concept of Chain of Infection and Infection Control Principles","authors":"George Jacob, M. Cummins","doi":"10.1093/oso/9780198801740.003.0027","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0027","url":null,"abstract":"For an infectious agent to spread to cause disease, certain conditions must be present. This process is called the chain of infection, which consists of six links: ● Causative agent; ● Infectious reservoir; ● Path of exit; ● Mode of transmission; ● Path of entry; and ● Susceptible host. Infection can occur when all six links are intact. By breaking this chain, the spread of infection can be stopped. ● Causative agent A micro- organism capable of causing infection is called a causative agent. Most commonly they are bacteria, viruses, fungi, and parasites. ● Infectious reservoir A reservoir of infection is the source from which infection can spread by allowing the pathogen to survive and possibly multiply. Humans, animals, and even inanimate environmental objects can serve as reservoirs of infection. There are many sources of infection in a healthcare setting. These include patients, healthcare workers, visitors, inanimate objects like medical equipment, and even the hospital environment. A human reservoir can be either an infected case, or a carrier, i.e. the person is colonized by a particular pathogen and does not present with any symptoms or signs of acute infection. Adherence to standard infection control practices is important as these asymptomatic carriers present a risk of cross infection, especially in healthcare surroundings. ● Path of exit The path of exit is how a pathogen leaves its reservoir. It normally refers to the site where the micro- organism grows. Common sites of exit associated with human reservoirs include the skin, mucous membranes, and the respiratory, gastrointestinal, and genitourinary tracts. ● Mode of transmission The mode of transmission is the route by which an infection spreads. Certain pathogens may use more than one route of transmission from reservoir to host. There are three common modes of transmission. This is the most common mode of infection transmission in a healthcare setting. It can occur either through direct contact when there is direct physical contact with the patient or indirect contact when the pathogen is transmitted from a contaminated intermediate object. Infection spreads through the airborne route when the susceptible person inhales infected particles in droplet nuclei of less than 5 μm.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"72 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":"133704069","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}