Evaluating the cost-effectiveness of strategies to prevent vascular access device infections.

The evidence clearly indicates that a care-bundle approach is needed to prevent catheter-related bloodstream infections (CRBSIs). Such an approach includes the need for education, training and adequate staffing, sterile barrier precautions, skin preparation, use of intravenous dressings and antimicrobial prophylaxis. Care bundles advise which aspects must be given priority and what procedures will produce optimum outcomes. All of these activities come at a cost, yet very few studies have investigated the extent to which they are cost-effective. As a result, it is difficult to make evidence-based decisions on the potential cost savings that may be achieved with a care-bundle approach. This article describes the existing health-economic evidence on strategies to prevent CRBSIs and outlines the criteria for future research.

Guidelines for the management of hospital-acquired pneumonia in the UK: report of the working party on hospital-acquired pneumonia of the British Society for Antimicrobial Chemotherapy.

These evidence-based guidelines have been produced after a systematic literature review of a range of issues involving prevention, diagnosis and treatment of hospital-acquired pneumonia (HAP). Prevention is structured into sections addressing general issues, equipment, patient procedures and the environment, whereas in treatment, the structure addresses the use of antimicrobials in prevention and treatment, adjunctive therapies and the application of clinical protocols. The sections dealing with diagnosis are presented against the clinical, radiological and microbiological diagnosis of HAP. Recommendations are also made upon the role of invasive sampling and quantitative microbiology of respiratory secretions in directing antibiotic therapy in HAP/ventilator-associated pneumonia.

Specimen transport audit.

A specimen transport audit was performed at a routine and reference laboratory. Over the survey period (1986-89) the percentage of specimens received and assessed as hazardous (inadequately packed, misidentified, or contaminated by leakage) fell significantly from 12.0 to 2.8%. Specimen transport audit identified technical and logistical faults associated with sample transmission. It is concluded that no type of hazard should exceed 0.5% of samples, with the total being less than 1% of specimens received. Specimen transport audit is an additional laboratory performance indicator.

Rapid organism identification from Bactec NR blood culture media in a diagnostic microbiology laboratory.

AIMS: To evaluate rapid organism identification on positive blood culture Bactec NR media (phial types 26, 27, 42 and 17), and to assess the usefulness of these procedures in a diagnostic microbiology laboratory. METHODS: Two hundred and sixty, first positive, blood culture bottles from individual patients were tested by rapid identification methods selected on the basis of Gram film organism morphology. Tube coagulase and latex agglutination were applied to presumptive staphylococci; latex agglutination antigen detection methods to suspected pneumococci, Neisseria and Haemophilus sp; and latex agglutination grouping tests for cultures thought to be non-pneumococcal streptococci. RESULTS: Media type did not influence test performance (p > 0.05 for all comparisons). Misapplication of methods occurred on eight occasions and there were 14 false positive results, nine involving the latex reagents for group C streptococci and pneumococci. The positive predictive values for tube coagulase tests and latex reactions for H influenzae type b, and N meningitidis groups B and C were 100%. The pneumococcal and staphylococcal latex tests gave positive predictive values of 94.1% and 62.5%, respectively, and the corresponding figure for streptococcal grouping reactions was 75.9%. With the exception of staphylococcal latex testing (80%) all investigation negative predictive values were > 90%. CONCLUSIONS: The performance of the staphylococcal latex agglutination method was unsatisfactory and it is not appropriate for use with the media studied. In view of the cross-reactions observed with the tests used to identify group C streptococci and pneumococci, positive findings must be interpreted with caution. In all other regards the protocol evaluated produced rapid, reliable, clinically useful information and, subject to local experience, is recommended to users of Bactec NR media.

The effect of specimen processing delay on borate urine preservation.

AIM: To investigate the effect on urine culture results and their clinical interpretation of delaying the processing of urine samples in which boric acid had been used as a preservative. METHODS: 792 mid-stream specimens of urine from patients attending their general practitioner were received in borate containing plastic jars. The specimens were cultured upon receipt, stored at room temperature, and then recultured the following morning. RESULTS: After overnight delayed culture, the results were altered in 16% of samples and the clinical interpretation of these findings differed in 8% of specimens. In 28 samples (3.5%) the bacterium isolated on initial culture was not the same as that obtained by culture after overnight storage. CONCLUSIONS: Boric acid urine preservation used for overnight delayed processing of samples is associated with a significant alteration in culture results and the attendant clinical interpretation of such specimens. Rapid transportation/processing of urine specimens must remain the optimum procedure.

An evaluation of gentamicin EMIT--its performance on the Kem-O-Mat and its role in the small laboratory.

An investigation was made into the use of gentamicin EMIT on the Coulter Kem-O-Mat in a small microbiology laboratory. EMIT was found to correlate well with plate assay and to be a more rapid, more precise and technically less time-consuming method. EMIT was more expensive in clinical use. This single disadvantage was considered to be outweighed by a saving in capital equipment expenditure and by the benefits to the laboratory and clinician.

Evaluation of new streptococcal latex grouping kit.

AIMS: To evaluate a new streptococcal latex grouping kit (Shield Diagnostics Ltd) and compare it against an established latex agglutination method (Streptex; Wellcome Diagnostics). METHODS: Two hundred and forty seven strains of streptococci and enterococci were tested with each kit by one operator and according to the manufacturer's instructions. Strains failing to group or giving discordant results were identified to species level. RESULTS: Two discrepant grouping results were observed and 13 non-beta haemolytic streptococci failed to group with either product. The Shield kit successfully identified 232 isolates at 15 minutes of enzyme extraction incubation compared with 224 and 233 on short (15 minutes) and long (1 hour) incubations, respectively, for Streptex (p > 0.23 for both comparisons). On short incubation only, the Shield kit detected significantly more strains of Enterococcus faecium (p = 0.007). The reaction strengths were similar for both kits (p > 0.16). No cross-reactions were observed but the Streptex kit produced significantly fewer tests with visible granularity (p < 0.003). CONCLUSIONS: Although the Shield product appeared to detect group D antigen more readily, overall no important differences in performance were observed. Prospective users of the new method should first become familiar with its characteristics.

Comparison of two automated quantitative immunoassays for the determination of C reactive protein concentrations.

Two quantitative, automated methods for the determination of C reactive protein (CRP) were compared: turbidimetry (Cobas Fara II, Roche, Welwyn Garden City, UK) and fluorescence polarisation TDx, Abbott, Wokingham, UK). One hundred and twenty routine serum samples submitted for measurement of CRP were tested using both procedures. The results were compared using regression line analysis and showed a high degree of correlation (r2 = 0.99, X coefficient = 1.01, constant = 0.11). C reactive protein can be accurately measured using the automated turbidimetric method which can be recommended as an alternative to fluorescence polarisation.

Investigation into the selection frequency of resistant mutants and the bacterial kill rate by levofloxacin and ciprofloxacin in non-mucoid Pseudomonas aeruginosa isolates from cystic fibrosis patients.

The frequency by which resistant Pseudomonas aeruginosa strains could be selected was compared for two antibiotics, levofloxacin and ciprofloxacin. Seven distinct strains were cultured on plates containing 1x, 2x, 4x and 8x the minimum inhibitory concentration (MIC) of the antibiotic under investigation. Resistant mutants were more readily isolated by growth on culture plates that contained ciprofloxacin, and the resulting MIC of the resistant mutant was also more frequently increased. Time-kill studies on comparable strains where the MIC for both antibiotics had increased by at least fourfold showed no difference between the two agents.

Randomized, double-blind study comparing 5- and 7-day regimens of oral levofloxacin in patients with acute exacerbation of chronic bronchitis.

A randomized, double-blind, multicentre study was conducted in adult patients with acute exacerbation of chronic bronchitis (AECB), to compare the efficacy of a 5-day course of levofloxacin 500 mg once daily, with the standard 7-day regimen at the same dose. Five hundred and thirty-two patients from 48 centres in 10 countries were randomized to receive levofloxacin: 268 and 264 received the 5- and 7-day courses, respectively. The primary efficacy analysis was the clinical response at 7-10 days post-treatment in the per-protocol (PP) population. Clinical success rates in the primary PP analysis of 482 patients were 82.8% (197/238) for the 5-day group and 84.8% (207/244) for the 7-day group. The difference in success rates was -2.1% with a 95% CI of (-9.1 to 4.9%). The bacteriological response showed eradication rates of 82.1% (92/112) and 83.2% (84/101) in the 5- and 7-day groups, respectively. Both treatments were well tolerated. These results show that for patients with AECB levofloxacin 500 mg once daily for 5 days provides equivalent clinical and bacteriological success to the same dose given for 7 days irrespective of the patient's age, the frequency of exacerbations or the presence of co-existing cardiopulmonary or chronic obstructive airways disease.

Worthwhile infection control information? A report from the 38th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC), San Diego, California: 24-27 September 1998.

A review is presented of some of the presentations delivered at ICAAC 1998. These cover the subjects of handwashing, occupational infections risk exposure for healthcare workers and alterations in catheter practice to reduce both intra-venous and urinary infections.

Investigation of infection in the neutropenic patient with fever.

Episodes of infection occurring in neutropenic patients are often associated with high levels of morbidity and mortality and prompt, accurate diagnosis allowing the rapid instigation of appropriate treatment can lead to an improved outcome. Recent developments in laboratory technology have increased the range of investigations available to the physician. The improved sensitivity of traditional microbiological culture, methods for antigen and antibody detection and the advances in molecular biology are among the reasons for an increased ability to detect both familiar and novel pathogens. This article describes the current methods available for determining the aetiology of an infectious episode in these patients. A plan of management for investigation of febrile episodes in neutropenic patients is suggested.

Perineal cleansing and midstream urine specimens in ambulatory women.

A prospective trial is reported of an assessment of perineal cleansing as a means of reducing bacterial contamination of midstream urine samples. One hundred and ninety-two asymptomatic antenatal ambulatory patients were randomly allocated into cleansing and non-cleansing cohorts. Quantitative urine microscopy and culture showed no significant differences between the groups. It is concluded that perineal cleansing has no role to play in the collection of midstream urine specimens from ambulatory women.

Cross infection in an intensive care unit by Klebsiella pneumoniae from ventilator condensate.

Klebsiella pneumoniae serotype K28 was cultured from six patients over 5 weeks in a general Intensive Care Unit. Colonized condensate in the ventilator expiratory water traps was the probable source of the organism, and hand carriage the vehicle of transmission. Although the cross-infection hazard of ventilator tubing condensate is recognized, there is no report in the literature of an outbreak caused by such fluid. Ventilator tubing condensate should be viewed as contaminated clinical waste and dealt with accordingly.

Hepatitis A immunity and travel history.

Travel histories were taken from 1111 British travellers. Serological testing showed that increasing age and a past history of jaundice were associated with a greater likelihood of travellers being immune to hepatitis A. Neither travel to nor the duration of stay in areas of increased hepatitis A endemicity influenced the level of hepatitis A immunity. It is concluded that travel histories from British citizens normally resident in the U.K. cannot be used to identify those travellers in whom serological prescreening would be of value prior to immunoglobulin prophylaxis.

Hepatitis A immunity in British adults--an assessment of the need for pre-immunisation screening.

A total of 858 British adults were screened for immunity to hepatitis A. Immune rates ranged from 13% in the 16-20 years age group to 61% in the 51-55 years age group. Factors affecting these rates are discussed and the implications for pre-immunisation screening are considered.

Lactobacillus rhamnosus infection in a child following bone marrow transplant.

We report a case where Lactobacillus rhamnosus was isolated from pericardial effusion and blood in a child following a bone marrow transplant for aplastic anaemia. A resume of cases in which this organism has been implicated as a pathogen is also presented.

Control of an outbreak of group C meningococcal meningitis with a polysaccharide vaccine.

An outbreak of meningitis in Royal Air Force recruits due to Neisseria meningitidis Group C type PI, 2 gave the first opportunity for polysaccharide vaccine to be used for controlling such an outbreak in the U.K. The effect of the vaccine on an epidemic in a large recruit training centre was studied after chemoprophylaxis had failed. With the possible exception of one vaccinee, further cases did not arise among camp personnel. Vaccination was continued until the carriage rate of the epidemic strain among recruits leaving the camp had fallen from greater than 19 to less than 1%. Two persons who had only indirect contact with the camp developed the disease. Vaccination early in the course of such an outbreak appears to be a useful and practical method of limiting symptomatic infection but not acquisition of the epidemic strain.

Primary meningococcal conjunctivitis and the need for prophylaxis in close contacts.

We present three cases of primary meningococcal conjunctivitis associated with systemic sepsis. The management of such patients should include combined topical and parenteral therapy with appropriate chemoprophylaxis for close contacts of cases.

Immunity to diphtheria in young British adults.

Of 906 recruits aged between 16 and 20 years who were Schick-tested upon entry to the Royal Air Force, 775 were tested for circulating Corynebacterium diphtheriae antitioxin by means of an indirect haemagglutination (IHA) method. Of the total population, 95.7% were Schick-test negative, 3.5% were Schick-test positive and 0.8% gave pseudo-reactions. Of those tested by the IHA test, 37.7% were regarded as immune, 47.0% as 'immune-susceptible' and 15.3% as non-immune. Discrepancies between the two tests were discovered. Of those persons found to be Schick-test positive, 34.6% possessed circulating antitoxin; of those Schick-test negative, 13.5% were regarded as non-immune. A history of diphtheria immunisation in childhood was found to be a poor predictor of immunity. A protocol for selective diphtheria immunisation of adults is proposed.