Empirical treatment of influenza-associated pneumonia in primary care: a descriptive study of the antimicrobial susceptibility of lower respiratory tract bacteria (England, Wales and Northern Ireland, January 2007eMarch 2010) Ruth M Blackburn, 1 Katherine L Henderson, 1 Mark Lillie, 1 Elizabeth Sheridan, 1 Robert C George, 2 Adrian H B Deas, 3 Alan P Johnson 1 ABSTRACT Objectives To determine the susceptibility of lower respiratory tract (LRT) isolates of Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae to antimicrobial agents recommended by UK guidelines for treatment of pneumonia associated with influenza-like illness. Methods Analysis of antimicrobial susceptibility data from sentinel microbiology laboratories in England, Wales and Northern Ireland was carried out. Subjects comprised patients who had an LRT specimen taken in a general practitioner surgery or hospital outpatient setting between January 2007 and March 2010. The main outcome measurements were antimicrobial susceptibility trends of LRT isolates over time, between patient age groups and in different geographical regions. Results Susceptibility to tetracyclines or co-amoxiclav was high. Of the 70 288 and 45 288 isolates with susceptibility results for tetracyclines or co-amoxiclav, 96% and 92%, respectively, were susceptible. Overall susceptibility to ciprofloxacin, ampicillin/amoxicillin and macrolides was lower than for tetracyclines or co-amoxiclav and varied markedly by organism. There were few clinically relevant variations in susceptibility to doxycycline or co-amoxiclav over time, geographically or between age groups. Conclusions The data support the use of doxycycline or co-amoxiclav as appropriate empiric treatment for LRT infection caused by the pathogens investigated, for patients in primary care. BACKGROUND Influenza may be complicated by pneumonia, which has two recognised types: primary viral and secondary bacterial infection. 1 2 Examination of pathological specimens from the 1918e1919 influ- enza pandemic suggested that secondary bacterial infection was the major cause of deaths associated with influenza-like illness (ILI) during that pandemic. 3 The prognosis of patients presenting with bacterial pneumonia rapidly worsens with delay in treatment, and effective empirical treat- ment (before or in the absence of a specific micro- biological diagnosis) is therefore a critical aspect of successful pandemic influenza planning. 45 Guidelines for the clinical management of patients with ILI during an influenza pandemic were compiled and published in 2007 by the British Infection Society, British Thoracic Society and Health Protection Agency (HPA) in collaboration with the Department of Health. 1 These guidelines regarded the pathogens likely to be associated with secondary bacterial pneumonia as Streptococcus pneumoniae, Staphylococcus aureus and Haemophilus influenzae. The guidelines suggest oral empirical treatment with either a tetracycline (usually doxycycline) or co-amoxiclav for patients in primary care. More recently, Department of Health guidelines introduced specifically for the 2009 H1N1 pandemic have reiterated the use of doxy- cycline or co-amoxiclav treatment for adult patients with influenza complicated by lower respiratory tract (LRT) infection that are not admitted to hospital. 6 Co-amoxiclav is recom- mended for children (except patients with peni- cillin allergy, who should be given clarithromycin). This paper seeks to assess microbiological evidence as to whether co-amoxiclav or tetracy- clines are appropriate empirical treatment for bacterial pneumonia in patients treated in the primary care setting. The analysis draws on susceptibility data for LRT isolates of S pneumoniae, S aureus and H influenzae as reported to LabBase2, the HPA ’s national communicable disease database. The database collects isolate data from laboratories across England, Wales and Northern Ireland and was extended to cover LRT isolates in 2006 as part of the pandemic influenza preparedness arrange- ments. The surveillance aims to support the timely modification of empirical treatment in the event that antimicrobial susceptibility patterns change. METHODS Antimicrobial susceptibility data for LRT isolates of H influenzae, S pneumoniae and S aureus reported between January 2007 and March 2010 were extracted from LabBase2 for laboratories in England, Wales and Northern Ireland. LRT isolates were primarily obtained from sputum, but other sources included alveolar lavage, bronchial/endo- tracheal aspirate, LRT, lung, pleura or pleural fluid. The data included all susceptibility test results for tetracycline, co-amoxiclav, ciprofloxacin, ampi- cillin/amoxicillin and macrolides for all three organisms as reported by hospital laboratories. Data on ciprofloxacin susceptibility in S pneumoniae < An additional table is published online only. To view this file please visit the journal online (http://thorax.bmj.com). 1 Healthcare Associated Infections and Antimicrobial Resistance Department, Health Protection Agency, Centre for Infections, UK 2 Respiratory & Systemic Infections Laboratory, Centre for Infections, Health Protection Agency, Centre for Infections, London, UK 3 Regional Epidemiology Unit, Health Protection Agency (East of England), Institute of Public Health, Cambridge, UK Correspondence to Ruth M Blackburn, Healthcare Associated Infections and Antimicrobial Resistance Department, Health Protection Agency, Centre for Infections, 61 Colindale Avenue, London NW9 5EQ, UK: ruth.blackburn@hpa.org.uk Received 5 January 2010 Revised 30 September 2010 Accepted 6 January 2011 Published Online First 25 February 2011 Thorax 2011;66:389e395. doi:10.1136/thx.2010.134643 389 Respiratory infection group.bmj.com on April 12, 2017 - Published by http://thorax.bmj.com/ Downloaded from