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

{"title":"The Biology of Viruses","authors":"A. Jeffery-Smith, C. Y. William Tong","doi":"10.1093/oso/9780198801740.003.0008","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0008","url":null,"abstract":"In order to be classified as a virus, certain criteria have to be fulfilled. Viruses must ● Be only capable of growth and multiplication within living cells, i.e. obligate intracellular parasite. Host cells could include humans, animals, insects, plants, protozoa, or even bacteria. ● Have a nucleic acid genome (either RNA or DNA, but not both) surrounded by a protein coat (capsid). ● Have no semipermeable membrane, though some have an envelope formed of phospholipids and proteins. ● Be inert outside of the host cell. Enveloped viruses are susceptible to inactivation by organic solvents such as alcohol. ● Perform replication by independent synthesis of components followed by assembly (c.f. binary fission in bacteria). Viruses are considered as a bundle of genetic programmes encoded in nucleic acids and packaged with a capsid +/ - envelope protein, which can be activated on entry into a host cell (compare this with computer viruses packaged in an enticing way in order to infect and take over control of your PC). Although they share some similarities in their properties, mycoplasma and chlamydia are true bacteria. The virion (assembled infectious particle) consists of viral nucleic acid and capsid. The nucleic acid of a virus can either be ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), and the amount of genetic material varies widely, with some viruses able to encode a few proteins and others having genetic material that encodes hundreds of proteins. In association with the nucleic acid there may be non- structural viral proteins, such as a viral polymerase. The nucleic acid and non- structural proteins are protected by a surrounding layer of capsid proteins. The capsid includes proteins which can attach to host cell receptors. The proteins and the cell receptors to which they bind determine a virus’ tropism, i.e., the ability to bind to and enter different cell types. The term nucleocapsid refers to the nucleic acid core surrounded by capsid protein. Some viruses also have an envelope made up of phospholipids and proteins surrounding the nucleocapsid. This envelope can be formed by the host cell membrane during the process of a virus budding from a cell during replication.","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":"129373627","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":"Common Organisms Responsible for Healthcare-associated Infection (HCAI)","authors":"George Jacob, M. Cummins","doi":"10.1093/oso/9780198801740.003.0026","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0026","url":null,"abstract":"MRSA are S. aureus which become methicillin resistant by the acquisition of the mec A gene which is on a mobile chromosomal determinant called staphylococcal cassette chromosome mec (SCC mec). The mec A gene encodes for a penicillin- binding protein (PBP2a) which has a low affinity for isoxazolyl-penicillins (MICs to oxacillin/ meticillin ≥ 4μg/ ml) and is resistant to all classes of beta-lactam antibiotics. Current Department of Health (DOH) guidance (2014) recommends that mandatory MRSA screening be streamlined to include only: ● All patient admissions to high- risk units; ● Healthcare workers; and ● All patients previously identified as colonized or infected with MRSA. The guidance also advises Trusts to follow local risk assessment policies to identify other potential high- risk units or units with a history of high endemicity of MRSA; and The guidance also recommends regular auditing of compliance with MRSA screening policy. The 2006 guideline for the control and prevention of MRSA in healthcare facilities recommends the following four measures. ● Isolation MRSA- positive patients should be nursed in a single room or if none is available, cohorting into a bay after risk assessment. Patient movement, and the number of staff and visitors looking after the patient, should be minimized. ● Hand hygiene and use of personal protective equipment (PPE) All staff and visitors should decontaminate their hands with soap and water/or an alcohol rub before and after contact with the patient or their immediate surroundings. Single-use disposable gloves and aprons/non- permeable gowns should be used by staff and visitors if there is a risk of contamination with body fluids. ● Disposal of waste and laundry All waste from colonized/ infected patients should be placed in the infectious waste stream. All linen and bedding from patients colonized/infected with MRSA should be considered as contaminated and processed as infected linen. ● Cleaning and decontamination The patient’s room should be cleaned/disinfected daily with an appropriate detergent/disinfectant as per local policy. On discharge of the patient, the room needs to be terminally cleaned before it is reused. All patient equipment should either be single-patient use or be cleaned, disinfected, and sterilized.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"701 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":"122267663","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":"Tools in Infection Prevention and Control","authors":"Stephanie J. Smith, M. Cummins","doi":"10.1093/oso/9780198801740.003.0029","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0029","url":null,"abstract":"The Health Act (2008) Code of Practice on the Prevention and Control of Infections and Related Guidance provides a legal statutory requirement to which all hospital trusts in England should abide to ensure the safety of patients and healthcare workers. There are similar laws in both Scotland and Wales. Prevention and control of healthcare- associated infections (HCAI) remains integral to provide safe, quality patient care and requires an effective management team to implement the Act. In July 2015, a revised Code of Practice was introduced for the prevention and control of HCAI. The Code of Practice is also referred to as the ‘Hygiene Code’ and is regulated by the Care Quality Commission (CQC). A requirement of this Act is that the board of directors receive an annual report from the Director of Infection Prevention & Control (DIPC), with acknowledgement of the report and approval of a proposed programme of delivery prior to public release and implementation. All trusts must register with the CQC, whose role is to regulate and inspect care services in the public, private, and voluntary sectors in England. Part of the CQC assessment against the Act includes Outcome 8: Cleanliness and Infection Control. Under this outcome the trust is required to demonstrate compliance. The DIPC within an organization will assume responsibility to provide assurances that criteria are met by ensuring regular committee meetings to discuss compliance with standards, monitoring of trends, and provide strategies to reduce HCAI. The trust has to be made accountable for any infection control issues for their staff and patients and have evidence of a clear framework to provide assurances that safety has been met. The IPC Team will implement a plan across their trust that requires quarterly and annual reports to ensure implementation and remedial actions listed and acted on as appropriate. A care bundle is a set of evidence-based interventions that are grouped together to ensure that patients receive optimal management consistently. Ideally, each part of the bundle should be based on evidence from at least one systematic review composed of multiple randomized control trials. Care bundles have been implemented in England since June 2005.","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":"129305713","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":"Skin and Soft Tissue Infections","authors":"R. Ghani, C. N. Fhogartaigh","doi":"10.1093/oso/9780198801740.003.0038","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0038","url":null,"abstract":"Skin and soft tissue infections (SSTIs) can be sub-divided based on the anatomical structure(s) affected from superficial to deep. Impetigo affects children more commonly than adults, starting as a macule of erythema and evolving into vesicles that rupture, leaving a golden crusted appearance. Fever and systemic signs are absent. It is highly transmissible and children should be excluded from school until exposed lesions have resolved. Folliculitis is a superficial infection presenting with small papules or pustules on an erythematous base around a hair. Fever and systemic signs are absent. If extension into deeper tissues occurs a dermal abscess (‘boil’ or ‘furuncle’) may occur, and several lesions may coalesce into a ‘carbuncle’. Deeper infection may cause discomfort, fever, and systemic upset. Any hair-bearing area may be affected, but sites most commonly affected include the face, scalp, axilla, inguinal area, thighs, or eyelid (‘stye’), and may be associated with shaved or occluded skin. Cellulitis is rapidly spreading erythema of the skin associated with pain, swelling, fever, and systemic features such as nausea and malaise. It may be seen as a complication of tinea pedis, superficial abrasions, or insect bites, venous insufficiency, lymphoedema, chronic ulcers, and diabetes. It is almost always unilateral and bilateral cellulitis is extremely rare and should prompt consideration of an alternative diagnosis. The Eron grading system can help guide treatment and admission decisions: ● Class I: the patient has no signs of systemic toxicity and no uncontrolled comorbidities. ● Class II: the patient is either systemically unwell or systemically well but with a comorbidity such as peripheral vascular disease, chronic venous insufficiency, diabetes, or obesity, which may complicate or delay resolution of infection. ● Class III: the patient has significant systemic upset such as acute confusion, tachycardia, tachypnoea, hypotension, or unstable comorbidities that may interfere with a response to treatment, or a limb-threatening infection due to vascular compromise. ● Class IV: the patient is septic or has life-threatening infection such as necrotizing fasciitis.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"1731 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":"129445691","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":"Blood-Borne Viruses","authors":"C. Tong, M. Hopkins","doi":"10.1093/oso/9780198801740.003.0034","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0034","url":null,"abstract":"Blood- borne viruses (BBVs) are viral infections transmitted by blood or body fluid. In practice, any viral infection that achieves a high viral load in blood or body fluid can be transmitted through exposure to infected biological materials. In western countries, the most significant BBVs are human immunodeficiency viruses (HIV1 and HIV2), hepatitis B virus (HBV) and hepatitis C virus (HCV). Other viruses that can be transmitted by blood and body fluid include human T cell lymphotropic viruses (HTLV1 and HTLV2), cytomegalovirus, West Nile virus and viruses responsible for viral haemorrhagic fever such as Ebola virus, Lassa virus, and Crimean-Congo haemorrhagic fever virus. BBVs are transmitted via exposure to blood and body fluid. Some examples of routes of transmission include: ● Sharing needles in people who inject drugs (PWID); ● Medical re-use of contaminated instruments (common in resource poor settings); ● Sharps injuries in healthcare setting, including in laboratories (less commonly through mucosal exposure); ● Transfusion of blood contaminated with BBVs (failure to screen blood donors); ● Transplantation of organs from BBV-infected donors; ● Sexual exposure to BBV-infected body fluid; and ● Exposure to maternal BBV infection: intrauterine, perinatally, or postnatally. If exposure to a BBV is via a needle stick injury in a healthcare setting, immediate first aid needs to be carried out by gently encouraging bleeding and washing the exposed area with soap and water. Prompt reporting of the incident is required so that an assessment can be done as soon as possible to determine if post-exposure prophylaxis (PEP) is required. The decision may be aided by urgent assessment of source patient infection status. The British Medical Association has issued guidance for testing adults who lack the capacity to consent. In the case of a sexual exposure to a BBV, immediate consultation to a genito-urinary medicine (GUM) clinic is warranted. The risk of transmission of BBVs associated with exposure depends on the nature of the exposure and the body fluid involved. The following factors are important in needle stick injuries: ● Deep percutaneous injury. ● Freshly used sharps. ● Visible blood on sharps.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"11 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":"126355674","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":"Urinary Tract and Genital Infections including Sexually Transmitted Infections (STIs)","authors":"J. Dave, C. Y. William Tong","doi":"10.1093/oso/9780198801740.003.0042","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0042","url":null,"abstract":"Urethritis, characterized by inflammation of the urethra in men, is caused by Neisseria gonorrhoeae (gonococcus), Chlamydia trachomatis, Trichomonas vaginalis, and Mycoplasma genitalium. Other causes of non-gonococcal urethritis include ureaplasmas, adenoviruses, and herpes simplex viruses. The presence of urethritis is confirmed by the presence of five or more polymorphs in urethral smear by high-power microscopy. Symptoms can be minor to profound and vary from clear to mucopurulent discharge. Gonococcus is commoner in men who have sex with men (MSM) compared to heterosexuals, and high-risk activities such as chemsex parties increase spread with significant public health consequences. Antibiotic resistance in gonococcus has clinical and public health implications as three cases of extensively drug-resistant Neisseria gonorrhoeae with resistance to ceftriaxone (MIC = 0.5 mg/L) and high-level resistance to azithromycin (MIC > 256 mg/L) have been described compromising current treatment recommended by British Association for Sexual Health and HIV Guidelines (BASHH). In England an outbreak of high level azithromycin-resistant gonococcus has also been described by Public Health England (PHE), who alerted clinicians about the need for follow up and test of cure, contact tracing, and treatment failure. C. trachomatis infection can be treated with azithromycin 1g orally as a single dose or with seven days of oral doxycycline. Risk factors for chlamydia include age younger than twenty-five years, multiple sexual partners, and avoidance of barrier methods for contraception. Metronidazole 2g single dose or 400– 500mg twice daily for seven days is recommended for treatment of trichomonas, which can cause a moderate discharge in up to 60% of males. Resistance to azithromycin and doxycycline is common in M. genitalium strains and management of these patients with urethritis requires GUM referral for comprehensive investigation, contact tracing, and public health notification. Molecular methods are used for the diagnosis of these organisms and gonococcal culture is undertaken to obtain antimicrobial susceptibility data from patients with a previous diagnosis by molecular method, in GUM attendees, and their contacts. Herpes simplex infection results in a painful ulcer preceded by a vesicle. The diagnosis can be confirmed using polymerase chain reaction (PCR) tests of a swab taken from the vesicle or ulcer.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"21 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":"126492116","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":"Opportunistic Infections in HIV Infection","authors":"E. Williams","doi":"10.1093/oso/9780198801740.003.0069","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0069","url":null,"abstract":"An infection is defined as opportunistic when it affects those with severe immunosuppression, i.e. takes a n opportunity to cause disease in a host with a weakened immune system. In people living with HIV it mainly affects those with a CD4 count < 200 although it is not impossible in those with CD4 count > 200. The CD4 percentage is also important as those with a CD4% < 14 are also more likely to have an OI. The lower the CD4 count the higher the risk of OIs, and some OIs are seen much more commonly with very low CD4 counts, e.g. cryptococcal meningitis in those with CD4 count of < 100. Before the introduction of antiretroviral therapy OIs were much more common than they are now, with previously up to 80% of those with AIDS having pneumocystis pneumonia (PCP). Since the introduction of antiretrovirals (ARVs) the rates of OIs has reduced greatly but unfortunately there are people who are still diagnosed late with an OI at diagnosis. Those with poor adherence or difficulty accessing ARVs are also more likely to be affected. In the UK in 2014, 40% of people diagnosed with HIV had a CD4 count of <350 which is defined as a late diagnosis (and 22% had a CD4 count of <200 which is defined as a very late diagnosis). In comparison to someone diagnosed with HIV early, those who are diagnosed late have a 10 times higher risk of dying in the year after they are diagnosed. This highlights the need for routine HIV testing so that people are diagnosed early to reduce the incidence of OIs further. The most common OIs seen in the UK are pneumocystis pneumonia (PCP), central nervous system (CNS) toxoplasmosis, cryptococcal meningitis, cytomegalovirus (CMV) retinitis, Mycobacterium avium intracellulare (MAI) infection and candidiasis. All those with HIV and a CD4 count ≤ 200, or with a CD4% < 14 should be given prophylaxis against PCP. Prophylaxis should also be recommended for those with oral candidiasis or a previous AIDs – defining illness. The options are co-trimoxazole 480mg od or 960mg 3x/week (960mg once daily can be given although does not confer any greater protection and has increased risk of side effects), dapsone 50mg once daily, or pentamidine nebulisers 300mg once every 4 weeks.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"13 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":"115376454","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":"Laboratory Quality Control and Accreditation","authors":"A. R. Oliver","doi":"10.1093/oso/9780198801740.003.0019","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0019","url":null,"abstract":"According to the International Organization for Standardization (ISO), the ‘Medical laboratories—Requirements for quality and competence (ISO 15189:2012) BS EN ISO 15189:2012’ accreditation is defined as ‘a procedure by which an authoritative body gives formal recognition that an organization is competent to carry out specific tasks’. Accreditation is delivered by the ‘competent authority’ based on a set of defined standards and the continual internal audit of the laboratory processes and infrastructure against these standards to achieve conformance. Additionally, the ‘competent authority’ periodically undertakes assessments to ensure compliance with the standards. These assessments vary in frequency and nature depending upon the assessment body. In some instances (e.g. UK Accreditation Service, UKAS), the assessments are annual and based on a four- year cycle covering the whole laboratory repertoire and infrastructure. The HSE is responsible for the inspection and licencing of microbiological containment level 3 and 4 facilities. The HTA is responsible for legal registration of laboratories that process and store human tissue, and is mainly histology related. The MHRA provides guidelines on good laboratory practice, good clinical practice, good clinical laboratory practice, and good manufacturing practice, largely around clinical trial work. It is also responsible for accreditation of blood transfusion laboratories. Finally, it provides guidance on the In Vitro Diagnostic Medical Device Directive (IVDMDD, 98/ 79/ EC) and the regulation of medical ‘devices’ including diagnostic devices, where a ‘device’ is defined as including reagent kits and analytical platforms. EFI provides guidance and standards for transplantation and tissue typing laboratories across Europe. Until 2009, CPA provided accreditation for the majority of UK pathology services. CPA was acquired by the UK Accreditation Service in 2009. UKAS is a government- appointed national accreditation body for the UK that is responsible for certification, testing, inspection, and calibration services, and is the competent authority for all ISO standards, not just pathology. It covers various sectors, including healthcare, food production, energy supply, climate change, and personal safety. The majority of UK pathology services will be UKAS ISO15189 accredited by 2018, including transitional ‘dual’ CPA standards/ ISO15189 accreditation between 2015 and 2018. It also provides ISO22870:2006 accreditation that is point of care specific, as well as ISO17025:2005, which applies to calibration standards.","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":"129695806","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":"Therapeutic Options for HIV Infection","authors":"S. Dakshina, P. Khan","doi":"10.1093/oso/9780198801740.003.0068","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0068","url":null,"abstract":"Treatment of HIV infection has seen dramatic developments since the start of the epidemic over thirty-five years ago. Since the advent of highly active antiretroviral therapy (HAART), HIV infection has gone from being a terminal illness with the inevitable development of AIDS to a now-treatable chronic condition with infected individuals living a ‘normal’ and healthy lifestyle when tested early and engaged in care. Antiretroviral therapy (ART) has become simpler with minimal pill burden and fewer side effects. In the UK ART can only be prescribed by a HIV specialist ensuring the patient is engaged in care and under regular monitoring and follow up. HIV infection affects the immune system through depletion of CD4 T-lymphocytes. There are several goals and aims of treating HIV infection. The main function of ART is to prevent HIV viral replication, which in turn reduces viral load (VL) and depletion of CD4 cells thereby preventing the development of AIDS and eventual mortality. HIV infection induces a pro-inflammatory state, which is associated with several conditions especially in late presenters. Common conditions include cardiovascular disease including cardiomyopathy, increased risk of venous thromboembolism due to a hypercoagulable state, HIV-associated nephropathy, disorders of the central nervous system, bone disorders, various dermatological conditions, and acceleration of ageing. Timely initiation of ART can help reduce and reverse such conditions. Studies demonstrate early initiation of ART and maintaining a suppressed VL minimizes the risk of onward sexual transmission of HIV. Though barrier protection is always advised in serodiscordant couples, recent studies support the reduced risk of transmission in virologically suppressed serodiscordant sexual couples, which has led to changes in post-and pre-exposure prophylaxis guidelines and enabling serodiscordant couples to conceive naturally. All HIV positive women should be initiated on ART and virologically suppressed ideally prior to conception. It is now routine practice in the UK and many parts of the world to perform HIV testing during pregnancy. If tested positive during pregnancy ART should be initiated and, depending on the stage of pregnancy and the VL, a Caesarean section may be necessary and the neonate may require prophylactic ART.","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":"120993510","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 the Immunocompromised Host","authors":"A. Riddell, M. G. Sanz","doi":"10.1093/oso/9780198801740.003.0050","DOIUrl":"https://doi.org/10.1093/oso/9780198801740.003.0050","url":null,"abstract":"An understanding of the main aspects and functions of the immune system is important, i.e. physical barriers, innate, humoral, and cell-mediated immunity (see Chapter 6, Basic Immunology), when caring for the immunocompromised patient. In adults, secondary immunodeficiency is much more common than primary, and is most often due to iatrogenic immunosuppression with drugs, e.g. corticosteroids, chemotherapy agents, immunosuppressive agents, ‘biological’ therapies. For example, treatment with corticosteroids for more than one month is enough to increase the risk of some fungal infections such as Candida and Pneumocystis jirovecii, such that PCP prophylaxis should be considered in patients receiving ≤ 20mg/day prednisolone for four or more weeks. Chemotherapy and immunosuppressive agents may cause profound immunosuppression. The degree and duration of immunosuppression following a transplant, and the conditioning regimen used before the transplant varies with respect to the type of transplant: heart and lung transplant recipients typically receive more significant immunosuppression, and so are at increased risk of opportunistic infection compared to other solid-organ transplant recipients. Infections (e.g. HIV), cancer, and autoimmune disorders and the treatment of these conditions can also affect the immune system. Other diseases are also considered immunosuppressive although the exact nature of this is less well defined, for example, poorly controlled diabetes mellitus increases the risk of candidal infections and common bacterial infections. Cirrhosis is also considered to be a relatively immunosuppressed state. Understanding the nature of immune defects in both primary and secondary immunodeficiency allows more accurate prediction of overall infection risk and risk of specific pathogens, allowing a rational approach to infection prevention and investigation when patients become unwell. The initial assessment of the immunocompromised host should be to identify why the patient is immunocompromised, how long they have been immunocompromised (is it a congenital or acquired immunodeficiency?), and whether there is potential for immune recovery. Clearly, a person with a congenital immunodeficiency will have lifelong susceptibility to specific infections, unlike an acquired deficiency due to chemotherapy or transplantation which may be transient. If the immunosuppression is due to a drug, is it possible to reduce or change the immunosuppression? If an infection is suspected, pre-immunosuppression infection screening results can help identify whether the current presentation represents reactivation of a latent infection or primary infection.","PeriodicalId":274779,"journal":{"name":"Tutorial Topics in Infection for the Combined Infection Training Programme","volume":"1219 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":"121430183","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}