Infections and antibiotics


Introduction

When healthy, the human body maintains a balance with commensal microorganisms that colonise skin and mucosal surfaces, including the gut ( Fig. 6.1 ). Disease occurs when the balance changes, either due to an encounter with a microorganism that has particular virulence or where a host defence is breached.

Fig. 6.1, Distribution of normal adult flora. Density of colonisation is greatest in the large intestine; density of colonisation varies by age and site.

Surgical practice has been transformed through prevention and control of infection and the correct and timely use of antimicrobials ( Fig. 6.2 ). An understanding of infection and its treatment is key for a surgeon to optimise outcomes for their patients, particularly with the increase in prevalence of noncommunicable diseases, healthcare-associated infection and antimicrobial resistance. Factors contributing to increased risk of infection in surgical practice and healthcare-associated infections encountered in surgical practice have been summarised in Tables 6.1 and 6.2 , respectively.

Fig. 6.2, Timeline of innovations related to infection prevention or management allowing step forwards in surgical practices.

Table 6.1
Factors, including noncommunicable diseases, contributing to increased risk of infection in surgical practice
Diabetes mellitus
Chronic kidney disease (associated with diabetes mellitus and hypertension)
Liver cirrhosis (causes include nonalcoholic fatty liver disease)
Obesity
Asplenia
Chronic obstructive pulmonary disease
Patients with some degree of immunosuppression, e.g.,

    • Previous solid organ or bone marrow transplant

    • Neutropenia due to systemic anticancer therapies

    • Biologic immunosuppressive therapies – monoclonal antibodies

Table 6.2
Important healthcare-associated infections encountered in surgical practice
Catheter-associated urinary tract infection
Peripheral venous cannula site infections
Bloodstream infections associated with vascular access devices
Ventilator-associated pneumonia
Surgical site infections
Clostridiodes difficile infection
Prosthetic material-related infection (including surgical mesh, biliary and urinary tract stents, prosthetic valve endocarditis, prosthetic joint infection, etc.)

Human biology and microbiology

Having an understanding of common bacteria and fungi encountered in surgical practice can assist the practitioner in interpreting microbiological investigations ( Tables 6.3 and 6.4 ). Where particular organisms are isolated may significantly change infection control precautions (transmission-based precautions) or the treatment plan. Furthermore, awareness of not only infective complications of surgery but also the causative organism may lead to identifying the need to change surgical practice. For example, rising surgical site infection (SSI) rates or repeated isolation of less commonly encountered or particularly resistant bacteria should prompt reflection on whether best practice is being followed.

Table 6.3
Common pathogens encountered in surgical practice
Organisms
Gram-positive cocci
Staphylococcus aureus
Colonisation of nose/skin occurs in a portion of the population.
Common infection site: Soft tissue and skin infections. Bone and joint infections. Surgical site infections.
HAI: Bloodstream infection from vascular access devices, infection of implanted devices/prosthetic material including prosthetic joints and valves.
Resistance: Methicillin (Flucloxacillin) resistance (MRSA) rates vary across the world.
Other staphylococcal species, e.g. Staphylococcus epidermidis, a skin commensal.
HAI: Healthcare-associated bloodstream infection from vascular access devices, prosthetic material including prosthetic joints and valves.
Resistance: Frequently methicillin resistant.
Streptococcus pyogenes (Group A Streptococcus ).
Common infection site: Along with other pyogenic streptococci (Group C + G, e.g., Streptococcus dysgalactiae ) associated with invasive disease, including wound and soft tissue skin infection and ENT infections.
Enterococcus faecalis/faecium
Common infection site: Urinary tract infections and GI tract surgical infections.
HAI: Encountered in urinary tract manipulation and prosthetic device infections. More commonly isolated from surgical site infections over time.
Resistance: Vancomycin resistance in enterococci (VRE) is encountered and can be problematic in surgical units. Enterococcal infection of prosthetic material can be difficult to cure with antibiotic therapy alone.
Gram-negative bacilli (coliforms)
Enterobacteriaceae (coliforms, e.g., most commonly Escherichia coli, but also includes Klebsiella, Enterobacter, Proteus, Citrobacter, Serratia spp.)
Common infection sites: Colon, biliary tract and urinary tract infection frequently implicated. Bloodstream infection commonly encountered in hospital.
HAI: Catheter-associated urinary tract infection are a frequent HAI.
Resistance: Antimicrobial resistance in these bacteria is increasing across the world. Resistance is commonly encountered to aminopenicillins (amoxicillin and ampicillin). Resistance rates to later generation cephalosporins and carbapenems (e.g., extended spectrum beta-lactamase-producing coliforms and carbapenamase-producing Enterobacteriaceae [CPE]). Varies widely across the world, though in some areas, resistance to these antibiotics along with fluoroquinolones (ciprofloxacin) and aminoglycosides can severely complicate the treatment of patients even with the simplest of infections.
Pseudomonas aeruginosa
Infection site: Urinary tract infections, respiratory tract infection in patients with bronchiectasis, opportunistic infection in immunocompromised hosts, particularly neutropenic patients. Often found colonising chronic wounds and ulcers.
HAI: Can be selected out by antimicrobial use, leading to infections with incomplete source control. Catheter-associated urinary tract infections. Due to environmental contamination, can be isolated from water sources within healthcare institutions and can lead to invasive infections in susceptible hosts.
Resistance: Significant intrinsic resistance reducing the range of available agents.
Serratia marcescens and Acinetobacter baumannii
Although incidence or infections with these bacteria vary across regions, over the last few decades these bacteria have been implicated more frequently in healthcare-associated infections, including hospital and ventilator-associated pneumonia, surgical site infections and urinary tract infections. These bacteria are frequently multidrug or even extensively drug-resistant organisms and can significantly complicate patient care. These organisms can also cause outbreaks due to equipment or environmental contamination.
Anaerobes
Bacteroides fragilis
Frequently implicated in colonic/intraabdominal infections and development of intraabdominal abscess and collections.
Clostridioides difficile
Production of toxins cause C. difficile infection, pseudomembranous colitis, in a susceptible host exposed to C. difficile spores in their environment after damage to gut bacteria from antibiotics.
HAI: One of the infections associated with antibiotic use that triggered the medical community to recognise the importance of antimicrobial stewardship.
Fungi
Candida albicans (other species also encountered including Candida paraspilosis, Candida tropicalis, Candida glabrata, Candida auris )
Common infection sites: Mild mucocutaneous C. albicans infections are common (oral and vaginal thrush). More severe mucocutaneous infection (oesophageal) is seen in patients with compromised T-cell function, e.g., people living with HIV and a low CD4 count. Bloodstream infections and more invasive disease are seen in patients with neutropenia or neutrophil dysfunction, including use of some systemic anticancer therapies.
HAI: An increase in invasive candidal infections is seen patients with prolonged broad spectrum antibiotic use, particularly in patients with neutrophil dysfunction including urinary tract infection in diabetics; neutropenia postchemotherapy; use of total parenteral nutrition; vascular access devices; and prolonged stays in critical care areas. Candidal infection is associated with gastrointestinal surgery particularly after anastomotic leaks and recurrent perforation in patients with antibiotic exposure.
Resistance: Resistance to fluconazole and other triazoles is increasingly encountered requiring the use of echinocandins, e.g., anidulafungin, particularly in some nonalbicans species.

Table 6.4
Antimicrobial recommendations based on organism
Organisms First-line antimicrobial (Local antimicrobial resistance patterns and treatment options may vary significantly) Option in patients with penicillin allergy or where resistance is more common
Staphylococcus aureus Flucloxacillin Vancomycin
Streptococcus pneumoniae Benzylpenicillin Levofloxacin
Streptococcus pyogenes Benzylpenicillin Clindamycin
Enterococcus spp. Amoxicillin Vancomycin or linezolid
Bacteroides fragilis Metronidazole
Enterobacteriaceae (coliforms, e.g., Escherichia coli ) Dependent on site of infection
Trimethoprim or gentamicin
Meropenem
Haemophilus influenzae Amoxicillin Doxycycline or coamoxiclav
Pseudomonas aeruginosa Piperacillin-tazobactam Meropenem
Clostridiodes difficile Metronidazole Vancomycin (orally)
Fidaxomicin in recurrent disease
Clostridium perfringens or Clostridium tetani Benzylpenicillin Metronidazole
Candida albicans Fluconazole Echinocandin, e.g. Anidulofungin

Bacterial resistance to antibiotics

Bacterial resistance to antibiotics is a phenomenon seen naturally in the environment. Use of antibiotics in human health, veterinary practice and agriculture has promoted the speed at which resistance has developed. Drug-resistant bacterial and fungal isolates are associated with worse clinical outcomes and increased healthcare costs.

Bacterial resistance can be intrinsic or acquired. Some of the more commonly encountered intrinsic resistance mechanisms include inability of the antibiotic to access the active site within the bacterial cell or being efficiently removed from the bacterial cell by an efflux pump. Acquired resistance occurs when mutations occur in chromosomal genes or when bacteria acquire new genes, e.g., plasmids allowing gene transfer between bacteria and bacterial species.

Acquired resistance mechanisms include:

  • Further reduction of the concentration of the antibiotic within the bacterial cells through reducing access (porin loss) or increasing efflux

  • Modification of the antibiotic target

  • Inactivation of the antibiotic through hydrolysis or other enzymatic modification of the antibiotic.

Resistance in Enterobacteriaceae, e.g., Escherichia coli and Klebsiella spp, has become a worldwide problem that affects nearly all aspects of healthcare including the ability to practice surgery. A number of resistance mechanisms can be seen, but one of the more commonly encountered mechanisms is the production of enzymes that hydrolyse some antibiotics, e.g., beta-lactamases and carbapenemases. Refer to Table 6.5 for the terms used in bacterial resistance and Fig. 6.3 for changes in resistance patterns over time in Staphylococcus aureus and Enterococci spp.

Table 6.5
Terms used in bacterial resistance
Adapted from Clin Microbiol Infect 2012; 18: 268–281.
Multidrug resistant organisms (MDRO) – defined as acquired nonsusceptibility to at least one agent in three or more antimicrobial categories
Extensively drug-resistant organism (XDRO) – defined as nonsusceptibility to at least one agent in all but two or fewer antimicrobial categories
Pan-drug-resistant organism (PDRO) – defined as nonsusceptibility to all agents in all antimicrobial categories.
Extended spectrum beta-lactamase (ESBL) - producing organisms – Enterobacteriaceae that produce a beta-lactamase ability to cleave third-generation cephalosporins and incompletely inhibited clavulanic acid or tazobactam.
Carbapenemase-producing Enterobacteriaceae or organisms (CPE or CPO) – carbapenemase enzymes produced by certain bacteria (frequently gram-negative coliforms such as Klebsiella spp.) that can cleave carbapenems. Carbapenems are some of the most effective antibiotics with alternatives having reduced cure rates and increased toxicities.

Fig. 6.3, Change in resistance pattern over time in Staphylococcus aureus and Enterococci spp.

Host defences and immunology

Structural barriers to infection include the skin and mucosal surfaces. Commensal organisms can prevent pathogens adhering to these surfaces, limit nutrient availability and produce chemicals such as mucus that interferes with the activities of or physically trap pathogens. Secretions prevent infection such as lysozyme in tears, acidic gastric secretions and proteins in urine to reduce the number or ability of pathogens to cause disease.

The immune system can be separated into the innate and adaptive immune system or cellular and humoral components. Pathogens are recognised by the innate immune system through pathogen-associated molecular patterns. Phagocytes use pathogen recognition receptors on their surface, such as the Toll-like receptor family. These receptors recognise different pathogen-associated molecular patterns such as peptidoglycan, flagellin or fungal proteins. Phagocytes include macrophages that can either be resident within tissues or derive from circulating promonocytes released from the bone marrow.

Neutrophils, another type of phagocyte with a shorter lifespan, are recruited into tissues when required. The stimulus from pathogen recognition receptor activation leads to a cascade of both cellular and humoral aspects of the immune response that result in an acute inflammatory process. This can include the complement cascade and release of acute phase proteins including interferons, interleukins and tissue necrosis factor. This leads to further immune cells being recruited into tissues and also cells (regulatory T cells) and molecules (interleukin-10), which moderate the immune response to prevent harmful tissue damage and overwhelming triggering of the host immune response. Other mechanisms for recruiting inflammatory cells include tissue damage, such as a skin breach during surgical procedure, which can release tissue factor as a trigger for the immune system.

The adaptive immune system has both humoral (antibodies produced by plasma cells derived from B lymphocytes) and cellular (T lymphocytes) aspects. These aspects are individually targeted to a pathogen and may take time to form a strong immune response. B cells often require the support of T cells to present antigens and set up an effective antibody response. T cells that have CD4 markers support macrophage intracellular pathogen destruction or support B cells to make antibodies. CD8 T cells are cytotoxic and kill cells infected with viruses.

Microbiological diagnostics in surgical practice

Microscopy and culture of biologic specimens remain key tools in the identification of pathogens to allow targeting of antimicrobial therapy. Routinely taking samples from patients with surgical infections enables targeted antimicrobial therapy and also builds up a pattern of antimicrobial resistance for commonly encountered pathogens. Understanding resistance patterns can help guide rational and safe antimicrobial prescribing in an institution or region.

For intraabdominal infections, blood culture and tissue/pus samples taken in theatre are vital investigations to optimise antimicrobial use and patient outcomes. Newer techniques in microbiology are allowing more rapid and accurate identification of microorganisms. The use of matrix-assisted laser desorption/ionisation – time of flight (MALDI-TOF) can accurately determine the identification of pathogens from cultured material. Other techniques involving nucleic acid amplification techniques and molecular probes for both chromosomal and ribosomal nucleic acids can allow the detection of pathogens where culture techniques fail. These techniques can be used to not only identify the pathogen but also, in some cases, identify genes conferring antimicrobial resistance to allow appropriate antimicrobial therapy.

6.1
Summary

  • Noncommunicable diseases contribute to the risk of infection in surgical practice.

  • Rate of bacterial and fungal resistance to antimicrobials is rising.

  • Microbiological sampling before antibiotics are administered, e.g., blood cultures, and samples taken during surgery can help target antimicrobial therapy and direct empirical antimicrobial-prescribing guidelines.

Infection prevention and control in surgery

Many aspects of infection prevention and control have been successful in reducing healthcare-associated infections in surgical practice.

Areas of standard infection control precautions should be taken into account in all patients and care settings, which include:

  • Patient placement

  • Hand hygiene ( Fig. 6.4 )

    Fig. 6.4, WHO - Five moments of hand hygiene.

  • Respiratory and cough hygiene

  • Personal protective equipment

  • Safe management of care equipment

    6.2
    Summary

    Infection

    • Invasion and multiplication of an organism with subsequent reaction in host tissues

    • Underlying disease may increase susceptibility (e.g., diabetes, chronic kidney or liver disease)

    • May be promoted by healthcare practices such as insertion of prosthetic material

    • Monitoring infection rates following surgery and causative organisms is essential to identifying where practice can be improved

  • Safe management of care environment

  • Safe management of linen

  • Safe management of blood and body fluid spillages

  • Safe disposal of waste (including sharps)

  • Occupational safety: prevention and exposure management (including sharps)

Transmission-based precautions should be taken into account when dealing with a specific infection or organism. In addition, infection prevention and control interventions deal with the management of outbreaks and incidents of infections. Specific interventions focussed on reducing SSIs are outlined in later sections.

Transmission of infections from patients to healthcare workers can be reduced by following standard infection control precautions. Patients with certain infections who also require surgical intervention may require healthcare workers to use additional personal protective equipment, and transmission-based precautions and recommendations should be followed.

Undertaking exposure-prone procedures in people living with blood-borne viruses is not uncommon. The protection offered by hepatitis B vaccination is typically sufficient to prevent transmission. Ensuring an adequate response to the vaccination (antibody levels to hepatitis B surface antigen) can also ensure correct postexposure prophylaxis is administered after contamination injury occurs. Hepatitis C transmission does occur during surgical practice, and hepatitis C is most prevalent in people who inject drugs and are exposed to unscreened blood products, including haemophiliacs. Hepatitis C treatment is highly successful in curing the infection with a short course of oral antiviral agents with excellent tolerability.

People living with HIV are unable to transmit the virus when they are taking HIV therapy, having achieved an undetectable HIV viral load in blood and remain adherent. This message of “undetectable equals untransmissible” (U = U) may change the stigma that people with HIV still face in healthcare settings. Postexposure prophylaxis against HIV is available and effective when taken rapidly after a contamination injury occurs, which is thought to carry a risk of HIV transmission.

6.3
Summary

Bacterial resistance

  • A naturally occurring phenomenon promoted by antibiotic use

  • A worldwide public health concern associated with increased mortality

  • Requires a multimodal approach including infection prevention, targeted antibiotic use, monitoring of resistant strains and development of new antimicrobials

Prophylactic antimicrobial in surgery

Aim

The main aim of antimicrobial prophylaxis in surgery is prevention of SSIs ( https://www.who.int/gpsc/ssi-prevention-guidelines/en/ ). In clean wounds, SSI rates may not be significantly reduced by antimicrobial prophylaxis, and therefore prophylaxis is not recommended for all types of surgery. Surgical antimicrobial prophylaxis may also reduce the risk of infection at the site of surgery, e.g., risk of urinary tract infection (UTI) in transurethral procedures in urologic surgery. Surgical antimicrobial prophylaxis is sometimes considered to prevent distant site infection, such as endocarditis or prosthetic joint infections, in patients with a predisposition undergoing surgery at a distant site. However, in general, evidence does not support this practice.

Administration considerations

To achieve high concentrations of drug at the surgical site at the time of incision, antibiotics should be administered 1 hour or less prior to skin incision. Where the antibiotic may take an hour or more to infuse, initiation of administration can be extended up to 2 hours prior to skin incision. Reviewing the need for surgical antimicrobial prophylaxis is included in the World Health Organisation’s surgical “pause” checklist. Although a single dose prior to skin incision is usually sufficient, intraoperative considerations may require additional doses to be administered, such as significant blood loss during surgery (>1.5 L blood loss), the length of the operation dependent on the antimicrobial’s half-life and type of surgery (in orthopaedic surgery with prosthesis implantation, antimicrobial prophylaxis may be continued for 24 hours).

Prolonging surgical antimicrobial prophylaxis has been proven not to further reduce the risk of postoperative infection and increases the risk of drug toxicity; selects out resistant organisms that compromise the treatment for the patient in the short term; and puts the patient at risk of other healthcare-associated infections, such as C. difficile infection.

Antimicrobial choice

The antibiotic chosen must cover the expected pathogens for the type of surgery. Patients who have been identified as having been previously exposed to carrying more resistant organisms such as MRSA may need an alternative prophylaxis recommendation. Most institutions or regions have surgical antimicrobial prophylaxis guidelines or policies that take into account local resistance patterns, MRSA carriage, patient’s penicillin allergy status and propensity to cause C. difficile infection (CDI). Where patients requiring surgery have also been identified as carrying more resistant gastrointestinal pathogens, such as VRE or Enterobacteriaceae resistant to the recommended prophylaxis, then discussion with an infection specialist may be required.

6.4
Summary

  • Standard infection control precautions are vital in all clinical areas.

  • Transmission-based precautions should be initiated when specific pathogens are suspected or isolated.

  • Surgical antimicrobial prophylaxis is a vital step to reduce postoperative infections, most importantly SSIs, but it must be administered correctly.

Antimicrobial stewardship in surgery

Antimicrobial stewardship is a term given to a range of activities ( Table 6.6 ). Within an institution or region, there is typically a team of specialists including doctors, pharmacists, nurses and data analysts supported by hospital epidemiologists, health psychologists, educationalists and communication experts, e.g., graphic designers dedicated to the optimisation of antimicrobial use ( Table 6.7 ).

Table 6.6
Elements of a hospital antimicrobial stewardship programme
  • 1.

    Guideline development and dissemination.

  • 2.

    Education and training on the use of antimicrobials.

  • 3.

    Pre- and postauthorisation of certain antimicrobials.

  • 4.

    Direct patient review and guidance to teams on optimal drug choice, dosing and duration.

  • 5.

    Developing tools and materials to allow clinical teams to review their own practice and improve the quality of antimicrobial use.

  • 6.

    Support for prescribing of antimicrobials where therapeutic drug monitoring is required (aminoglycosides, glycopeptides, etc.).

  • 7.

    Data collection and analysis on the use of antimicrobials and feedback to clinical teams.

  • 8.

    Data collection and analysis of antimicrobial-resistance patterns to influence empirical antimicrobial prescribing.

  • 9.

    Data collection on harm or difficulties with use of antimicrobials, e.g., Clostridioides difficile infection, incorrect dosing of medication with analysis and feedback.

  • 10.

    Engagement with infection prevention and control teams to consider overlap and support of interventions.

Table 6.7
Examples of areas for review in a surgical antimicrobial stewardship programme
  • 1.

    Empirical antimicrobial choices and whether they follow institutional guidelines.

  • 2.

    Timing and duration of antimicrobial prophylaxis.

  • 3.

    Frequency of microbiological sampling before antimicrobials are administered where recommended.

  • 4.

    Quality and documentation of antibiotic review at 48–72 hours.

  • 5.

    Duration of antimicrobials for particular indications.

Antimicrobial stewardship is a key patient safety activity with which every member of the clinical team must be involved. Furthermore, the public should have an understanding of the harms and risks associated with the inappropriate and overuse of antimicrobials and antimicrobial-resistant organisms.

It is the role of the individual doctor, nurse and pharmacist to be aware and engage with the activities that lead to improving the use of antimicrobials in their own clinic, ward or operating theatre. Antimicrobial stewardship is there to improve the immediate outcome for patients, minimise harm and prevent the development of antimicrobial-resistant organisms for that patient in the short to medium term as well as the wider community over a longer time period.

Antimicrobial-prescribing behaviours

In the UK in 2015, the Public Health England issued “Start smart, then focus” guidance focussed on a few key areas for hospital-based practice ( Fig. 6.5 ).

Fig. 6.5, Public Health England Summary Start Smart then focus guidance and toolkit.

Other areas where antimicrobial use can be minimised include:

  • Promoting source control to mitigate the need for antimicrobials, e.g. abscess drainage, appendectomy, biliary stent for cholangitis.

  • Using the shortest effective course for treatment. Many common infections have been proven to be safely and effectively treated with short courses of antibiotics ( https://www.bradspellberg.com/shorter-is-better ), including:

    • Lower UTI in women – 3 days

    • Pneumonia – 3 to 5 days

    • Intraabdominal infections – 4 to 8 days

    • Gram-negative bloodstream infections – 7 days

  • Using narrow-spectrum antibiotics with minimal effect on gut microbiome and avoiding the 4C antibiotics (coamoxiclav, ciprofloxacin, cephalosporins and clindamycin).

  • Following local institutional antimicrobial guidelines.

Surgical antimicrobial stewardship programmes

Behaviour or culture of a clinical team can influence prescribing. Surgical specialties have particular timetables and cultural norms. Antimicrobial stewardship must be embedded into these cultural norms and routines to be effective. Different approaches may be needed between and within different surgical and medical specialties.

Behavioural studies in surgical departments have been undertaken to understand antimicrobial use in surgery. It is not infrequently seen that antimicrobial prescribing is deferred to less experienced members of the team.

Antimicrobial stewardship teams must engage senior decision makers in surgical specialties to engage with guideline development, quality improvement and provide feedback. Influencing change can be difficult. Use of data, particularly data personalised to the prescriber or responsible surgeon, can be very powerful. Comparing data between teams and individuals can lead to discussion of why clinical practice may differ and whether harmonisation of practice is required to reduce variation.

Use of quality improvement methodology can help a clinical team choose a focus for improvement ( Table 6.7 ).

Regular, personalised and face-to-face feedback can help change practice. The antimicrobial stewardship team must understand the factors that drive behaviours in a clinical area including what common indications for antimicrobials are seen in practice, whether they appear in current guidelines and reduce ambiguity or uncertainty in the use of the guideline. This can only be achieved through engagement with all levels and types of healthcare workers in that area. Considering issues of motivation, capability or opportunity of the observed behaviour will aid the antimicrobial stewardship team to identify behaviours to improve practice. Education alone will rarely change behaviour. Developing long-term sustained improvement must consider system design and how best practice can become routine. Training and assessment to facilitate optimal behaviours, seeking microbiology advice in complex cases and proactive patient review by infection specialists in certain settings, such as transplantation or oncology, may all help achieve the best outcomes for patients.

6.5
Summary

  • Antimicrobial stewardship is vital to optimise patient outcome in surgical practice.

  • Engaging with the institution’s antimicrobial stewardship team will ensure the needs of surgical patients are considered.

  • Quality improvement programmes and audits can identify areas of practice where antimicrobial-prescribing behaviours may not be optimal.

Approach to a patient with a possible or probable infection

Given the diverse range of surgically relevant conditions caused by infection, a structured approach to patient assessment and management can help facilitate safe and effective care. Infection can result in a wide spectrum of disease severity, requiring careful consideration of disease and patient factors. Infection may progress locally (e.g., spreading phlebitis at a vascular access site), embolise (e.g., infective endocarditis with splenic abscess formation) or disseminate (e.g., staphylococcal or candidal bloodstream infection). Even with a localised infection, the body may mount a systemic response. This systemic response can become unregulated, leading to life-threatening organ dysfunction, known as sepsis.

Sepsis definition

International Surviving Sepsis Campaign (SSC) guidelines 2004 promoted early goal-directed therapy. The definition of sepsis was based on the suspicion of an infection along with systemic inflammatory response. The original definition caused considerable concern due to the low specificity of the systemic inflammatory response to identify those who have an infection, those requiring hospitalisation and those requiring antibiotics, never mind urgent antibiotic administration. There remains tension between identifying those patients who will most benefit from early interventions and the harm associated with excessive oxygen delivery, intravenous cannulation, urinary catheter placement, rapid intravenous fluid administration and the overuse of broad spectrum antibiotics.

Other tools have been introduced that may more accurately describe a population of patients who do require more rapid assessment and intervention. This group of patients may also more often require management within a critical care area and have higher mortality.

Sepsis 6

The UK Sepsis Trust first developed the Sepsis 6 tool in 2006 to be used in emergency departments and wards, which could be delivered in a wider range of settings ( Table 6.8 ). It has been modified over time to address questions raised about the interventions promoted. The latest iteration from UK Sepsis Trust, 2020, now includes in the assessment side “Red Flags”, which are indicative of organ dysfunction that promote the use of the intervention “Sepsis 6” side of the tool.

Table 6.8
Sepsis 6
  • 1.

    Ensure senior clinician attends. Not all patients with red flags will need the Sepsis 6 urgently.

  • 2.

    Oxygen if required.

  • 3.

    Obtain IV access, take bloods. Blood cultures, blood glucose, lactate, FBC, U&Es, CRP and clotting. Lumbar puncture if indicated.

  • 4.

    Give IV antibiotics. Maximum dose broad spectrum therapy. Consider local policy/allergy status/antivirals.

  • 5.

    Give IV fluids.

  • 6.

    Monitor. Use NEWS2. Measure urine output.

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