Is the VIDAS B.R.A.H.M.S PCT assay able to detect a bacterial throat

infection?

Mr Ajith P GeorgeMBChB, MRCS, DO-HNS

ENT SpR

Overview

• Aims & Objectives• Background• Methodology• Further investigations

Aims

• 1- To establish whether the VIDAS BRAHMS PCT assay is sensitive enough to detect a proven bacterial infection of the throat

• 2- To establish whether PCT rises following routine tonsillectomy

• 3- To determine whether post tonsillectomy secondary haemorrhage (PTSH) is associated with a bacterial infection

Objectives

• To reduce routine unnecessary prescription of antibiotics in ENT.– Reduce Cost– Decrease incidence of allergic reactions– Decrease side effects of medication– Slow the progression of antibiotic resistance

Background• Unnecessary antibiotic prescribing is leading to

an increase in bacterial resistance1

• Procalcitonin in the management of LRTI’s has been demonstrated to– Reduce antibiotic prescribing2

– Decrease antibiotic cost per patient2

• Patients admitted for PTSH to ENT units across the UK are routinely prescribed antibiotics

• There is no clear evidence to suggest PTSH is associated with a bacterial infection3

What is Procalcitonin?

• 116 AA polypeptide pro-hormone of calcitonin• Produced in c-cells• Released from the liver during the acute

phase response• Bacterial specific marker of infection- Levels

related to severity

Current applications of PCT

• Managing LRTI• Acute exacerbation of COPD• Differentiating viral and bacterial meningitis• Pneumonia sepsis induced ARDS• PUO• Differentiating sterile and infective

pancreatitis

Evidence for PCT benefit

• Christ-Cain et al compared PCT based therapeutic strategy against conventional management

• N=243, Single blinded cluster RCT (119 standard group and 124 PCT group)

Management

• Hx, examination, TPR, FBC, U&E’s, CXR, MC&S, ABG’s, Spirometry, Bronchoscopy

Outcomes of Christ-Cain et al

• P>0.05– QOL– VAS– WCC– CRP– Admission– Hospital stay– Death– ITU

• P<0.05– Antibiotic prescription– Duration of antibiotic

prescription– Antibiotic cost per

patient

Methodology• Stage I

– A cross sectional analysis to establish a mean PCT level for patients with a proven bacterial throat infection• To determine whether the assay is sensitive enough

• Stage II– A case control study to determine whether a significant difference

exists in mean PCT levels of post tonsillectomy patients (control) against patients with a bacterial throat infection• To determine whether tonsillectomy causes a rise in PCT

• Stage III– A case control study to determine a significant difference in mean PCT

levels of PTSH patients against post tonsillectomy patients (control)• To establish whether PTSH is associated with a bacterial infection and

therefore justifies antibiotic prescription

Further Investigations

• Do patients admitted with Glandular Fever Justify antibiotic prescription?

• Determining between viral and bacterial acute otitis media in children

• Differentiating bacterial or inflammatory causes of acute salivary gland disease

• Investigating the use of high sensitive PCT to determine if bipolar tonsillectomy is more traumatic than the cold steel technique.

Thank you!

References• 1-Cars O, Hogberg L, Murray M et al. Meeting the challenge

of: A concerted global response is needed to tackle rising rates of antibiotic resistance. Without it, we risk returning to the pre-antibiotic era warn Otto Cars and colleagues.BMJ 2008; 337: a1438.

• 2-Christ-Cain M, Jaccard-Stolx D, Bingisser R et al. Effect of Procalcitonin-guided treatment on antibiotic use and outcome in lower respiratory tract infections: cluster-randomised single-blinded intervention trial. The Lancet 2004; 363: 600-607

• 3-George A, Coulson C, De R. Procalcitonin: A bacterial specific marker of infection. Clinical Otolaryngology 2007; 32(4):310.