Journal of Hospital Infection (2002) 51: 237±239
Letters to the Editor doi:10.1053/jhin.2002.1241, available online at http://www.idealibrary.com on
Quality indicators for antibiotic control programmes Sir, We read with interest Nathwani et al.'s1 paper on quality indicators for antibiotic control programmes. We too are concerned about sub-optimal use of glycopeptides. Vancomycin is widely used in our Trust and we were concerned that it should be used and monitored appropriately.2,3 We therefore carried out an audit of vancomycin prescribing, administration and monitoring. Hammersmith Hospitals NHS Trust has about 1000 inpatient beds across two main sites. All adult patients prescribed more than one dose of intravenous vancomycin at any time during a two-week period were included. Patients whose courses began prior to the first day were included; patients whose courses continued beyond the last day were followed up until vancomycin was stopped or for a further week, whichever was the sooner. Copies of
request forms for vancomycin levels received by the microbiology laboratory on site A during the study period were also obtained; similar data were not readily available at site B. The standards audited against are shown in Table I. According to Nathwani et al.'s1 table of possible indicators for use in antimicrobial control programmes, we consider that service quality (efficiency) was measured by standard 6; risk (safety) by standards 2 and 5; and technical quality (appropriateness) by standards 1, 3, 4. Assessment of outcome (effectiveness) and staff participation (competence) were not an integral part of this particular audit. A total of 49 patients were included, representing a wide range of clinical specialities on both sites. Of the 49 patients, 42 were prescribed regular doses and seven repeated `stat' doses due to renal impairment. The start date was recorded for 41 of 42 patients prescribed regular doses. A total of 143 vancomycin levels were requested for the 49 patients during the two-week study period, representing a median of two per patient (range 2±11). We obtained copies of all 115 vancomycin level request forms for
Table 1 Summary of audit standards and key results Audit standard
Key findings
1. All patients prescribed vancomycin should have an appropriate initial dose based on body weight and estimated creatinine clearance, according to Trust guidelines
21 (43%) of 49 patients had appropriate initial doses prescribed. Of the remaining 28 (57%), 18 (64%) were subsequently changed to a more appropriate dose following pharmacists' advice
2. Patients on regularly prescribed vancomycin should not miss any doses unless specifically requested by medical staff
10 (20%) patients had missed doses. Six missed one dose, four missed more than one dose
3. All patients on regularly prescribed vancomycin should have a trough level taken before their third or fourth dose, according to Trust guidelines
16 (39%) patients had the first level taken before their 3rd or 4th dose; 10 (24%) had their first level taken early and 15 (37%) patients had their first level taken late or never
4. Requests for vancomycin levels should be on a microbiology form and accompanied by three pieces of information: details of the dose prescribed, time of last dose and time of blood sample 5. At least 75% of levels should be within the desired reference range
27 (23%) of 115 request forms had all relevant information completed; 46 (40%) had none of the three pieces of information completed
6. If levels are not in the reference range, doses should be adjusted appropriately on the day on which the result was reported
For the nine patients with trough levels above 10 mg/L, three were adjusted on the same day and six did not have their doses adjusted. For the four patient with troughs below 5 mg/L, two were adjusted on the same day and two were not adjusted
0195-6701/02/070237 + 03 $35.00/0
Of the 28 levels documented as troughs, 15 (54%) were in the desired range (5±10 mg/L); of the 99 levels for which the type of level was unknown, 45 (45%) were between 5±10 mg/L, 11 (11%) were below 5 mg/L and 43 (43%) were above 10 mg/L
& 2002 The Hospital Infection Society
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Letters to the Editor
the patients on site A. The results are summarised in Table I. One of the main problems highlighted was that request forms were rarely completed with details of the time of the last dose and the time at which the blood sample was taken. This made it impossible to determine whether many of the levels were trough, peak or `random' levels, although in line with current recommendations4 it is Trust policy only to measure trough levels in the majority of patients. Because information on the type of level was rarely available, auditing against some of our other standards was difficult. We found there was room for improvement in prescribing, administration and monitoring. However the main problem was in completion of the request forms. Our interventions have included increasing awareness amongst clinicians, pharmacists and nursing staff. We have presented the results at the medical audit round, held training sessions for pharmacists and phlebotomists on each site, written an article for the Trust newsletter, which is distributed to all staff and is widely read and introduced an initiative whereby pharmacists are encouraged to complete antibiotic level request forms. We are now analysing the results of a reaudit that took place during April 2002, six months after the first audit. If no improvement is identified, we plan to write to all consultants whose teams submit incomplete request forms, and are considering asking for samples accompanied by incomplete forms to be resubmitted to the microbiology laboratory. As Nathwani et al.1 suggest, we also found that the development of simple indicators to assess the quality of antimicrobial use was helpful in trying to improve use of vancomycin in our Trust. F. J. Cooke B. Deany
PHLS Specialist Registrar in
Medical Microbiology, Department of Infectious Diseases and Microbiology, Hammersmith Hospital, London, UK yPrincipal Pharmacist and Director, Academic Pharmacy Unit, Hammersmith Hospitals NHS Trust/ School of Pharmacy, University of London, UK
References 1. Nathwani D, Gray K and Borland H. Quality indicators for antibiotic control programmes. J Hosp Infect 2002; 50: 165±169.
2. Begg AJ, Barclay ML, Kirkpatrick CJM. The therapeutic monitoring of antimicrobial agents. Br J Clin Pharmacol 1999; 47: 23±30. 3. MacGowan AP. Pharmacodynamics, pharmacokinetics and therapeutic drug monitoring of glycopeptides. Ther Drug Mon 1998; 20: 473±477. 4. Saunders AJ. Why monitor peak vancomycin concentrations? Lancet 1994; 344: 1748±1750.
doi:10.1053/jhin.2002.1225, available online at http://www.idealibrary.com on
Cluster of clinical isolates of epidemic methicillin-resistant Staphylococcus aureus (EMRSA) with a negative deoxyribonuclease (DNase) testÐimplications for laboratory diagnosis and infection control Sir, Staphylococcus aureus is an important pathogen and epidemic methicillin-resistant strains (EMRSA) in particular cause outbreaks in the hospital setting.1 Such outbreaks are an additional burden on the health service.2 The correct identification of S. aureus, particularly if it is an MRSA strain, is therefore important for patient management and infection control. The standard tests used in the hospital laboratory to distinguish S. aureus (including MRSA) from other staphylococci include a positive slide agglutination test (to detect protein A and/or bound coagulase) and a positive DNase test to detect extracellular deoxyribonuclease activity. However we describe a cluster of infections due to MRSA isolates that were DNase negative and discuss the potential implications of this. Over a 25-day period, DNase negative MRSA strains were isolated from wound swabs from four patients. All of them had just undergone surgery for arterial vascular insufficiency. All the patients had subsequently developed surgical-site wound infections due to DNase negative MRSA. They had all received perioperative prophylaxis with flucloxacillin and had all been on the same ward at some stage of their hospital admission. All the infections responded to therapy with vancomycin. Appropriate infection control measures were taken and no further Author for correspondence: A. O. Qamruddin, Department of Medical Microbiology, Manchester Royal Infirmary, Oxford Road, Manchester, M13 9WL.