Beyond safety considerations for other patients and staff in the immediate vicinity, those practising in the field of infectious diseases, microbiology and virology must have proficient knowledge, skills and behaviour relating to the public health considerations of communicable disease control. Practitioners must be able to describe the public health issues relating to communicable diseases and to specific infections (incubation periods, transmission routes, vaccinations available, need for mandatory notification), as well as understand basic epidemiological methods and the functions of health protection and environmental health teams.

The cornerstone of practice for practitioners in infectious diseases, microbiology and virology is the ability to diagnose and manage important clinical syndromes where infection is in the differential diagnosis. Practitioners must hold a detailed knowledge (covering the epidemiology, clinical presentation, relevant investigations and management and prognosis) of both community-acquired and healthcare-associated infections. This knowledge must cover infections in all body compartments and those causing systemic infections (such as blood-borne viruses). This must incorporate patients presenting from the community, and infections which develop among those already undergoing healthcare treatment for other conditions. In this latter group, infections among surgical patients and those colonised and infected with multi-drug-resistant organisms must be able to be managed with confidence. Similarly, common clinical infection syndromes presenting among patients returning from travel abroad must be able to be recognised, investigated appropriately and treated promptly. Practitioners must also be able to manage infections among special populations, including itinerant populations, those who may misuse drugs or alcohol, those at the extremes of age or who are pregnant and immunocompromised individuals. Specific to immunocompromised individuals, this should encompass both those with primary and with secondary immunocompromise.

In a clinical setting, practising infectious diseases medicine must incorporate knowledge, skills and behaviour to prevent onward spread of communicable diseases to other patients and to members of staff. The mode of transmission of communicable diseases must be understood, and practitioners must be able to interrupt their onward transmission. This includes the use of personal protective equipment for clinical interactions; from the types of equipment available, to their indication and the legislation surrounding their use (including Health and Safety at work). This also includes the use of isolation facilities; the indications for side rooms, negative pressure ventilation rooms; and when and how to arrange transfer to high-consequence infectious diseases units.

Patients living with human immunodeficiency virus (HIV) have particular health needs relating to their diagnosis, the opportunistic infections which can affect them, and the chronic disease management of their condition which is impacted by the disease process itself and the medication used to control it. Practitioners working with patients living with human immunodeficiency virus must hold knowledge of the pathophysiology and natural history of the disease, the therapeutic options available for virological control and the likely complication from HIV and the medications. Practitioners must be able to safely monitor and interpret the test results of patients living with human immunodeficiency virus. They must also be able to advise on strategies to decrease onwards transmission of HIV, including pre-and post-exposure prophylaxis. Practitioners managing patients living with human immunodeficiency virus must be able to identify and treat the opportunistic infections which may arise.

The nature of infectious diseases means that they are not bound by political or social boundaries. Practitioners in infectious diseases, microbiology and virology must, therefore, be competent in the recognition and management of imported infections and be aware of mechanisms to identify prevalent infections in different geographical areas. Practitioners must also be able to recognise problems of non-communicable diseases among immigrants from low- and middle-income settings. Practitioners in infectious diseases must also be competent in giving pre-travel medical advice including vaccination against communicable diseases and prophylaxis (both physical and chemical).

Microbial and host cellular biology and interactions dictate the breadth of clinical infection practice, from colonisation to invasion to infection. Understanding the classifications used for bacteria, viruses, fungi and parasites aids clinical and laboratory diagnosis and ultimately patient management. Understanding the common host responses to infective agents at the cellular level enables appropriate clinical management both with direct acting anti-infectives and other supportive therapy.

A basic understanding of the mechanism of action and indication for antimicrobials is held by most prescribers. The key properties of different classes of antimicrobials, their anticipated side effects and the spectrum of activity against different pathogens is inherent in most undergraduate and post-graduate medical curricula. Practitioners in the fields of infectious diseases, microbiology and virology must have a firm grasp of this knowledge, and should be able to apply it to patients with bacterial, viral, fungal or parasitic infections. They must be able to integrate this knowledge with the pharmacokinetic properties of the antimicrobials, and should be able to adapt this in differing patient populations including those with renal impairment or on renal replacement therapy and those with allergies or other host factors.

Limiting the spread of communicable diseases within a healthcare setting is integral to patient safety and clinical practice. Practitioners in infectious diseases, microbiology and virology often lead infection prevention and control teams, and are often responsible for creating and implementing policies and ensuring their effectiveness. They are also often responsible for investigating outbreaks when there are lapses in practice, or other causes for onwards transmission of infectious agents.

To provide an effective infection specialist service, practitioners must be conversant in pre-analytical, analytical and post-analytical elements of laboratory practice, irrespective of the specific areas of infectious diseases undertaken on a day-to-day basis. Pre-analytical skills and knowledge will include areas such as understanding the microbial differential diagnoses sufficiently to advise on and obtain the correct tests on the optimal sample types, be this for culture or for serological or genetic diagnostic tests. Pre-analytical skills also help practitioners identify where tests will not aid diagnosis, including for conditions which are currently diagnosed clinically and for which laboratory diagnostics do not currently exist. Analytical skills and understanding will vary depending on the area of practice, but will include safe laboratory work, the strengths and limitations of different tests, the impact of quality assurance and quality control and the cost implications of different modalities. Post-analytical skills and understanding will include contextualisation of results in each patients’ care, awareness of positive and negative predictive values of different tests and implications for further diagnostics including reflex testing.

Practitioners in the field of infectious diseases, microbiology and virology must be proficient in advising on vaccination against communicable diseases. Practitioners must have a working knowledge of World Health Organisation’s (WHO) childhood vaccination schedules, occupationally indicated vaccinations and the use and timing of post-exposure vaccinations. Practitioners should also be aware of adverse event profiles of vaccines and of the contraindications to certain vaccine preparations in certain patient cohorts.