Abstracts e17

Citrobacter spp, we specifically looked at organisms re-sistant to both amoxicillin and trimethoprim. Mecillinamwould be a useful alternative to nitrofurantoin in treatingthese infections. We also found that all ESBL-producingisolates were sensitive to mecillinam. This is in agreementwith one similar study from Cardiff, although other groupshave found higher levels of resistance.

Conclusions

Mecillinam is an effective antibiotic against urinary isolatesfrom Tayside which, if used more widely, could reduce theuse of broad spectrum agents such as cefalexin, co-amoxiclav and ciprofloxacin.

A COMPARATIVE STUDY OF ANTIBIOTIC GRADIENTDEVICES FOR THE DETERMINATION OF MIC FORAMIKACINCATEGORY: LESSON IN MICROBIOLOGY& INFECTION CONTROL

Sophie WitheyThermo Fisher Scientific, Basingstoke, United Kingdom

Introduction

The ability to simply and accurately determine antimicro-bial susceptibility is of fundamental importance to theroutine clinical microbiology laboratory. M.I.C.EvaluatorTM

strips are an effective, time-saving alternative to tradi-tional agar/broth dilution and are available individuallypackaged for ease of use and storage.

Scientific findings

A range of 259 clinically significant organisms was tested,including staphylococci, streptococci and Enterobacteria-ceae. Overnight cultures were used to make a 0.5 McFar-land suspension of each isolate for both the gold standardagar/broth dilution and plate inoculation. Plates wereincubated in appropriate conditions according to BSACand CLSI methods. Results were used to determine theessential agreement (EA) (calculated as a percentage ofresults within -1.5 to +1.0 doubling dilutions of thereference method) of amikacin M.I.C.E. strips and amikacinEtestTM strips to BSAC/CLSI gold standard methods.

Discussion

Amikacin M.I.C.E. strips achieved an EA greater than 90%across all groups of organisms for both CLSI and BSACmethods. Etest scored less than 90% EA in 6 out of 11 casesfor CLSI and nine out of eleven cases for BSAC. Whenfollowing the CLSI and BSAC methods, amikacin M.I.C.E.strips had an EA equivalent to or better than Etest in 10 outof 11 and 11 out of 11 cases, respectively.

Conclusions

M.I.C.E. strips performed consistently better than Eteststrips and are significantly better than Etest when followingthe BSAC method (P¼0.0013). Oxoid M.I.C.Evaluator(M.I.C.E.TM) strips provide a rapid, accurate and reliable al-ternative to traditional agar/broth dilution methods.

AUDIT ON MANAGEMENT OF COMMUNITYACQUIRED PNEUMONIA IN PATIENTS REQUIRINGHOSPITALISATIONCATEGORY: CLINICAL LESSON

Isabel Baker, Kim JacobsonNorth Bristol NHS Trust, Bristol, United Kingdom

Introduction

Community acquired pneumonia (CAP) is an importantcause of illness and death in the UK, with a recent increasein incidence by 34% over a period of 10 years. Studies havereported mortalities of over 50%, depending on the severityof disease. To ensure optimal management, national andlocal guidelines have been published providing advice oninvestigation and treatment of these patients. Guidelineshave been revised to take the development of new testsand the rise in health care-associated infections intoconsideration. Our audit aimed to investigate, if patientsare being managed according to these guidelines.

Scientific findings

We performed a retrospective review of patients admittedwith CAP over a period of 2 months. 120 cases wereincluded. A severity assessment as recommended in theguidelines based on the CURB-65 score was documented in32% of cases. 17.5% of patients did not have all therecommended investigations done, but in the sub-groupof patients with CAP of high severity this was 95%. In 53% ofpatients the choice of empirical antibiotic was according tolocal guidelines, (74% when using either local or nationalguidelines). In patients with a negative outcome thetreatment was compliant with the local guidelines in 50%.

Discussion

There are differences between the local and nationalguidelines in the recommendations given regarding investi-gations and treatment, which may lead to confusion.However, both require a severity assessment as the basisto decide on the extent of microbiological investigation, aswell as on choice of empirical antibiotics. In the majority ofcases this was not documented. A marked number ofpatients did not have the recommended investigationsdone, this was especially high in the group of patientswith CAP of high severity, and were given empiricalantibiotics noncompliant with the guidelines.

e18 Abstracts

Conclusions

Investigation and treatment of patients hospitalised withcommunity acquired pneumonia was not compliant withlocal and national guidelines in a significant number ofpatients. Further education of clinicians is needed.

ANAEROCOCCUS LACTOLYTICUS CAUSINGA MYCOTIC AORTIC ANEURYSMCATEGORY:CLINICAL LESSON

Damian Mawer 1, Duncan Parry 2, Julie Logan 3,Anu Rajgopal 2

1 Leeds Teaching Hospitals NHS Trust, Leeds, UnitedKingdom2Calderdale and Huddersfield NHS Foundation Trust,Huddersfield, United Kingdom3Molecular Identification Services, Centre for Infection,London, United Kingdom

Introduction

Anaerobic bacteria are a rare cause of mycotic aorticaneurysm (MAA). One reason for this may be that theorganisms are often fastidious and do not grow well onstandard laboratory media. The advent of moleculartechniques such as the identification of RNA from the16S ribosomal subunit of bacteria by polymerase chainreaction (16S PCR) has offered the opportunity to identifyorganisms from clinical specimens that are culture nega-tive. This allows better management of patients withdifficult or unusual infections, including those caused byanaerobic organisms. We report the first case of Anaero-coccus lactolyticus causing MAA. The organism was identi-fied using 16S PCR. It is normally sensitive to b-lactams(including penicillin) and metronidazole, but managementof infections caused by Anaerococcus species is not welldescribed. In addition there is limited published data onthe optimum treatment of MAA. In this case the patient re-sponded to a seven week course of b-lactams andmetronidazole.

Scientific findings

A 66 year old man presented with rigors, weight loss andthoracic back pain. He took daily prednisolone for rheuma-toid arthritis. Physical examination revealed a pulsatilemass in his epigastrium. Computerised tomography identi-fied a 5.2cm infrarenal abdominal aortic aneurysm. Thepatient underwent a laparotomy which found an MAA. Theinfected material was resected and a vein graft repairperformed. Culture of both blood and operative samplesdid not yield any pathogens. Ribosomal RNA from Anaero-coccus lactolyticus was later identified in two specimens.A prolonged course of b-lactam antibiotics (meropenemthen benzylpenicillin) and metronidazole was given witha good clinical response.

Discussion

Mycotic aortic aneurysms are usually caused by Grampositive organisms, such as Staphylococcus aureus, orGram negatives, such as Salmonellae. Anaerobes are rarelyimplicated and when isolated usually belong to the Bacter-oides group. To our knowledge this is the first case in whichan Anaerococcus is the causative pathogen. Its identifica-tion was achieved using 16S PCR. This molecular techniqueis a valuable tool for identifying fastidious organisms. In thiscase it had a direct impact on clinical management, allow-ing the spectrum of antibiotic therapy to be narrowed ap-propriately and the duration of treatment to be betterdefined.

Conclusions

Mycotic aortic aneurysm is a serious infection associatedwith a high mortality. This case highlights three clinicallessons. Firstly, whilst rare anaerobic organisms can causeMAA and must be considered in the differential diagnosis.Secondly, it is important to identify the causative pathogento help narrow the spectrum of treatment, as a prolongedcourse of antimicrobials is required. Sensitive moleculartools, such as 16S PCR, may aid this process and should beemployed when culture techniques fail. Finally, this patientresponded to prompt surgery and a seven week course ofantibiotics, supporting current recommendations for themanagement of MAA.

PVL - ENCODING STAPHYLOCOCCUSAUREUSPRESENTING AS A COMMUNITY ACQUIREDSUBDURAL EMPYEMA WITH MENINGITIS BY TEJALDESAI (1), DAVID GARNER (2) AND NIGELCUMBERLAND (2)1. WESTERN SUSSEX HOSPITALSNHS TRUST, WORTHING, WEST SUSSEX2. FRIMLEYPARK HOSPITAL NHS FOUNDATION TRUST,SURREYCATEGORY: LESSON IN MICROBIOLOGY &INFECTION CONTROL

Tejal Desai 1, David Garner 2, Nigel Cumberland 2

1Western Sussex Hospitals NHS Trust, Worthing, WestSussex, United Kingdom2 Frimley PArk Hospital NHS foundation Trust, Frimley,Surrey, United Kingdom

Introduction

Staphylococcus aureus causes a wide spectrum of dis-ease from mild soft tissue infections to toxic shock syn-drome, endocarditis and meningitis.Approximately 30% ofthe population are asymptomatic carriers at any one time(1).Panton-Valentine Leukocidin (PVL) was first describedin 1932 (2), and is an exotoxin present in approximately2% of clinical isolates of Staphylococcus aureus.The exo-toxin destroys white blood cells and promotes tissue necro-sis. In the United Kingdom, PVL is produced mostly by