How and when to use CSF to investigate neonates and children with possible central nervous system infection.

A child presented to the emergency department with fever, reduced consciousness, irritability and reduced oral intake. Infective meningitis and encephalitis were within the differential diagnoses. Is a lumbar puncture (LP) indicated and, if so, what is the optimal timing of LP? Will antimicrobial pretreatment affect the cerebrospinal fluid (CSF) results? How can clinicians optimise diagnostic stewardship to benefit individual patients and society at large? Interpretation of rapidly available CSF biochemical tests (protein, glucose and lactate levels) and microscopy can provide a prompt insight into the infective aetiology and inform treatment and further diagnostic testing strategies. Diagnosis of an aetiological pathogen in a patient presenting with central nervous system (CNS) infection has clinical, infection control and public health implications. A plethora of tests are available to enable CSF analysis in patients with possible CNS infection. We aimed to summarise current evidence and guidance to ensure the best possible use of the diagnostics available.

A Pragmatic Study to Evaluate the Use of a Rapid Diagnostic Test to Detect Group A Streptococcal Pharyngitis in Children With the Aim of Reducing Antibiotic Use in a UK Emergency Department.

OBJECTIVE: Sore throat is a common presentation to the children's emergency department (ED), and many patients are likely prescribed antibiotics unnecessarily. We aimed to reduce antibiotic prescribing for sore throat in our UK ED through use of an established scoring system combined with a rapid diagnostic test (RDT) to detect group A streptococcal (GAS) pharyngitis. METHODS: AB single-subject and diagnostic accuracy studies were used to measure both antibiotic prescribing rates over time and the performance of the McIsaac clinical score combined with RDT to screen for and treat GAS pharyngitis. All children between the age of 6 months and 16 years with symptoms of sore throat were eligible for inclusion. The study adhered to SQUIRE guidelines. RESULTS: During 2014 and 2016, antibiotic prescribing rates for 210 children at baseline (median age, 3 years) and 395 children during the intervention (median age, 2 years) were assessed. The baseline prescribing rate was 79%, whereas rates after intervention were 24% and 27%, respectively. The RDT had an acceptable false-negative rate of 7.9%, poor sensitivity of 64.3%, and a negative predictive value of 92.1% when compared with conventional throat culture. A McIsaac score of 3 or more had good sensitivity (92.11%) but very low specificity (12.62%) for predicting GAS infection. CONCLUSIONS: Despite poor RDT sensitivity and the McIsaac score's poor specificity in children, their use in combination decreased antibiotic prescribing rates in a children's ED setting.

Increasing the volume of blood received in adult paired blood culture bottles at a regional public health laboratory: results of a quality improvement project to optimise the diagnosis of bacteraemia.

BACKGROUND: Optimising the diagnosis of bacteraemia has clinical, infection control and antimicrobial stewardship benefits. It's well documented that volume of blood received in blood culture bottles affects test sensitivity. The ability of blood cultures to detect bacteraemia is proportional to the volume of blood cultured. We undertook a period of baseline measurement and established that mean blood culture fill volume was inadequate. AIM: The primary aim was to increase the percentage of adequately filled blood cultures (≥5ml) by 20% and increase the percentage of optimally filled bottles (8-10ml) by 10% in six months (by 1st August 2018). Our secondary aim was to increase the mean volume in blood culture bottles to 8ml (by 1st August 2018). We measured the clinical impact of this on test sensitivity by comparing blood culture positivity rate between adequately and inadequately filled bottles. METHODS: Following a period of baseline measurement we implemented three phases of plan/do/study/act (PDSA) intervention cycles (including a small test pilot cycle). Interventions were focused around user education/engagement, real time user feedback and laboratory reporting. User questionnaires were administered to investigate knowledge and practice; further informing the interventions. RESULTS & CONCLUSION: Between 1st March - 1st August 2018 the mean volume of blood inoculated into culture bottles rose from 5ml (95% CI 4.1-6.0ml) to 7.5ml (95% CI 6.4-8.5ml). The percentage of adequately-filled (≥5ml) blood culture bottles increased from 47% to 61% (absolute increase of 14%) and the percentage of optimally-filled (≥8ml) bottles increased from 16% to 29% (absolute increase of 13%). Although our project didn't fully meet its aims, we observed a significant and sustained improvement in filling of blood culture bottles.