Multihospital outbreak of Clostridium difficile ribotype 027 infection: epidemiology and analysis of control measures

OBJECTIVE

To report a large outbreak of Clostridium difficile infection (CDI; ribotype 027) between June 2007 and August 2008, describe infection control measures, and evaluate the impact of restricting the use of fluoroquinolones in controlling the outbreak.

DESIGN

Outbreak investigation in 3 acute care hospitals of the Northern Health and Social Care Trust in Northern Ireland.

INTERVENTIONS

Implementation of a series of CDI control measures that targeted high-risk antibiotic agents (ie, restriction of fluoroquinolones), infection control practices, and environmental hygiene.

RESULTS

A total of 318 cases of CDI were identified during the outbreak, which was the result of the interaction between C. difficile ribotype 027 being introduced into the affected hospitals for the first time and other predisposing risk factors (ranging from host factors to suboptimal compliance with antibiotic guidelines and infection control policies). The 30-day all-cause mortality rate was 24.5%; however, CDI was the attributable cause of death for only 2.5% of the infected patients. Time series analysis showed that restricting the use of fluoroquinolones was associated with a significant reduction in the incidence of CDI (coefficient, -0.054; lag time, 4 months; P = .003).

CONCLUSION

These findings provide additional evidence to support the value of antimicrobial stewardship as an essential element of multifaceted interventions to control CDI outbreaks. The present CDI outbreak was ended following the implementation of an action plan improving communication, antibiotic stewardship, infection control practices, environmental hygiene, and surveillance.

A point prevalence survey of antibiotic prescriptions: benchmarking and patterns of use

AIM

The aim of the study was to assess current patterns of antibiotic prescribing and the impact of a hospital antibiotic policy on these practices.

METHODS

The study involved collecting information regarding hospitalized patients utilizing the ESAC audit tool.

RESULTS

In the study site hospital, the use of the restricted agents was low whilst the use of the non-restricted agents was high. Compliance with the hospital antibiotic guidelines was 70%.

DISCUSSION

The findings identified monitoring non-restricted antibiotics and compliance with guidelines as targets for quality improvements in our hospital. Point prevalence surveys may offer a simple method of monitoring antibiotic policies, thus, informing antibiotic stewardship.

Cost implications of the use of troponin I (cTnI) measurement to diagnose heart conditions

Focal points

The impact of hospital antimicrobial policy on the incidence of Clostridium difficile infection

Focal points

Clinical and economic impact of contaminated blood cultures within the hospital setting

Blood cultures have an important role in the diagnosis of serious infections, although contamination of blood cultures (i.e. false-positive blood cultures) is a common problem within the hospital setting. The objective of the present investigation was to determine the impact of the false-positive blood culture results on the following outcomes: length of stay, hotel costs, antimicrobial costs, and costs of laboratory and radiological investigation. A retrospective case-control study design was used in which 142 false-positive blood culture cases were matched with suitable controls (patients for whom cultures were reported as true negatives). The matching criteria included age, comorbidity score and month of admission to the hospital. The research covered a 13-month period (July 2007 to July 2008). The findings indicated that differences in means, between cases and controls, for the length of hospital stay and the total costs were 5.4 days [95% CI (confidence interval): 2.8-8.1 days; P<0.001] and £5,001.5 [$7,502.2; 95% CI: £3,283.9 ($4,925.8) to £6,719.1 ($10,078.6); P<0.001], respectively. Consequently, and considering that 254 false-positive blood cultures had occurred in the study site hospital over a one-year period, patients with false-positive blood cultures added 1372 extra hospital days and incurred detrimental additional hospital costs of £1,270,381 ($1,905,572) per year. The findings therefore demonstrate that false-positive blood cultures have a significant impact on increasing hospital length of stay, laboratory and pharmacy costs. These findings highlight the need to intervene to raise the standard of blood-culture-taking technique, thus improving both the quality of patient care and resource use.

Modelling the impact of antibiotic use and infection control practices on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus: a time-series analysis

OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen worldwide. A wide range of factors have been suggested to influence the spread of MRSA. The objective of this study was to evaluate the effect of antimicrobial drug use and infection control practices on nosocomial MRSA incidence in a 426-bed general teaching hospital in Northern Ireland.

METHODS

The present research involved the retrospective collection of monthly data on the usage of antibiotics and on infection control practices within the hospital over a 5 year period (January 2000-December 2004). A multivariate ARIMA (time-series analysis) model was built to relate MRSA incidence with antibiotic use and infection control practices.

RESULTS

Analysis of the 5 year data set showed that temporal variations in MRSA incidence followed temporal variations in the use of fluoroquinolones, third-generation cephalosporins, macrolides and amoxicillin/clavulanic acid (coefficients = 0.005, 0.03, 0.002 and 0.003, respectively, with various time lags). Temporal relationships were also observed between MRSA incidence and infection control practices, i.e. the number of patients actively screened for MRSA (coefficient = -0.007), the use of alcohol-impregnated wipes (coefficient = -0.0003) and the bulk orders of alcohol-based handrub (coefficients = -0.04 and -0.08), with increased infection control activity being associated with decreased MRSA incidence, and between MRSA incidence and the number of new patients admitted with MRSA (coefficient = 0.22). The model explained 78.4% of the variance in the monthly incidence of MRSA.

CONCLUSIONS

The results of this study confirm the value of infection control policies as well as suggest the usefulness of restricting the use of certain antimicrobial classes to control MRSA.

An innovative approach to integrated medicines management

RATIONALE, AIMS AND OBJECTIVES

To determine whether an increased input by clinical pharmacists at each stage of the patient's hospital journey, from admission through discharge, resulted in an enhanced level of patient care as measured by a number of clinical and economic outcomes.

METHODS

This project was designed to address medicines management issues in patients deemed at risk of drug-related problems. During the project, these latter patients at the time of admission were randomly assigned to an integrated medicines management (IMM) service group (n = 371) or regular hospital care group (n = 391). The IMM service involved comprehensive pharmaceutical care provided by a pharmacy team throughout each of three stages: patient admission, inpatient monitoring and counselling, and patient discharge.

RESULTS

Patients who received the IMM service benefited from a reduced length of hospital stay [by 2 days (P = 0.003; independent samples t-test log(e))]. IMM patients also had a decreased rate of readmission over a 12-month follow-up period (40.8% vs. 49.3%; p = 0.027; Fisher's exact test) and an increased time to readmission [20 days longer (P = 0.0356; log rank test)]. A numbers-needed-to-treat calculation indicated that for approximately every 12 patients receiving the IMM service, one readmission to hospital, within 12 months of discharge, would be prevented. The new service was welcomed by cognate health care professionals.

CONCLUSION

The IMM service proved very effective and can be used as a template to support the implementation of comprehensive pharmaceutical care as a routine service across Northern Ireland and beyond.

A HRG-based costing model for estimating pharmacy costs associated with surgical procedures

OBJECTIVE

The present study addresses pharmacy expenditure within a surgical directorate in a UK hospital. The aim of the study was to develop a health care resource group (HRG)-based costing model that can be used to forecast pharmacy expenditure based on surgical casemix. Such a model will be of benefit as an expenditure projection tool at a time when hospitals are developing accelerated operation programmes in an attempt to decrease hospital waiting times.

METHOD

During the period February-April 2000, nursing staff recorded all pharmacy sourced items for each individual operation in the theatres used for general surgery, ENT surgery and gynaecological procedures; each operation was also classified according to its HRG. The associated costs of the items per HRG were identified and the average pharmaceutical cost per HRG calculated and included in the costing model. The model derived costs over the study period were compared with the actual pharmacy expenditure which was obtained from the pharmacy computer system. Finally HRG data for operations carried out in February 2002 were costed using the model for validation purposes.

RESULTS

The estimated pharmaceutical cost for surgery items for February-April 2000 was 121,235 UK pounds. This figure was 3.92% over the actual pharmaceutical expenditure as determined from computer records. The February 2002 casemix varied considerably from that of 2000. However, the model estimated pharmaceutical cost of surgery performed in February 2002 (38,054 UK pounds) was again very similar to the computer logged expenditure (1.09% under the actual expenditure for that period) indicating the robustness of the HRG-based costing approach.

The identification of barriers preventing the successful implementation of a surgical prophylaxis protocol

AIM

The aim of this study was to introduce a protocol for the use of antimicrobials in surgical prophylaxis for the described procedures in Antrim Area Hospital.

METHOD

Historical data of antimicrobial use were obtained from retrospective analysis of patients' charts, for those patients identified as having one of the following 'clean/contaminated' surgical procedures over the previous six months; cholecystectomy or abdominal hysterectomy. These data were analysed, and a protocol was introduced providing guidelines for the choice of antimicrobial agent, its administration time, route, dose, duration and frequency of treatment.

MAIN OUTCOME MEASURE

The main outcome measure was the success of the uptake of the protocol following its implementation.

RESULTS

There was a total of 285 patients identified, 105 prior to and 180 post implementation. Overall, 68% of patients received some form of prophylaxis in the first cycle, and 72% in the second.

CONCLUSION

Although the introduction of the protocol led to slight improvements in compliance with standard prescribing procedures, with an increase in single-dose prophylaxis, and a reduction in prolonged prophylactic treatment, the improvements did not reach expectations. This paper attempts to identify the possible barriers to protocol implementation.

Management of Helicobacter pylori eradication--the influence of structured counselling and follow-up

AIMS

Helicobacter pylori (H. pylori) eradication rate varies according to the treatment regimen used and other factors, e.g. antimicrobial resistance and patient compliance. The aim of the present study was to evaluate the influence of patient counselling and follow-up on H. pylori eradication rates and to document the effectiveness of a 1 week eradication regimen consisting of lansoprazole (30 mg once daily), amoxicillin (1 g twice daily) and clarithromycin (500 mg twice daily).

METHODS

Seventy-six dyspeptic patients, who at endoscopy were found to have gastritis, duodenitis or ulceration, and a positive H. pylori urease test, were recruited. Patients were randomly assigned to an intervention group (n = 38) or a control group (n = 38). Intervention patients received their medicines via the hospital pharmacy and were counselled (and followed up) by a hospital pharmacist. Control patients were given a standard advice sheet and referred to their GP who prescribed the same therapy.

RESULTS

Intervention patients exhibited a statistically significant improvement in the H. pylori eradication rate (94.7% vs 73.7%; P = 0.02) and compliance (92.1% vs 23.7; P < 0.001). Of the 64 H. pylori eradicated patients, 62 were able to eliminate their antisecretory medication compared with only 12 of the H. pylori persistent patients (P < 0.001). A pharmacoeconomic evaluation indicated that counselling and follow-up reduced the direct costs of eradication by approximately 30 UK pounds per patient.

CONCLUSIONS

Structured patient counselling and follow-up can have a significant effect on H. pylori eradication rates and should be a routine part of therapy.

Point-of-care testing. Cost issues and impact on hospital operations

Advancing technology has allowed for the migration of laboratory testing from the central laboratory to the near-patient setting, leading ideally to a shorter therapeutic turnaround time. This potential benefit, however, comes with a price tag. Assessing the cost-benefit ratio on a per test basis cannot effectively be done in a generalized manner, because each hospital must evaluate this with respect to its own unique circumstances. There are, however, certain outcomes, such as decreased LOS and decreased blood-product usage that, if achieved, far outweigh the cost of POCT, justifying its use. Any hospital attempting to implement POCT must also realize that hospital operations are affected by such use and that adjustments and careful laboratory oversight are required.

Evaluation of the performance and clinical impact of a rapid intraoperative parathyroid hormone assay in conjunction with preoperative imaging and concise parathyroidectomy

BACKGROUND

(99m)Tc-sestamibi scans and rapid, intraoperative intact parathyroid hormone (PTH) assays allow preoperative identification of diseased glands and intraoperative confirmation of diseased gland removal, respectively. Use of these two new technologies may facilitate simpler, more concise surgery, shorter hospital stays, and decreased costs for frozen-section analysis. One major drawback to this new strategy has been the high cost of rapid point-of-care PTH assays.

METHODS

We performed rapid PTH assays with the DPC Turbo PTH assay on the DPC IMMULITE automated analyzer. The number of intraoperative frozen sections, type of anesthesia, surgical approach, length of hospital stay, and pre- and postoperative calcium values were compared between a group of 49 patients undergoing parathyroidectomy where the intraoperative PTH assay was used in conjunction with preoperative imaging, and a historical control group of 55 patients before the use of these two technologies in our institution.

RESULTS

Comparison of the Turbo PTH assay to the standard IMMULITE PTH assay gave the following: y = 1.08 x - 4.36 (r = 0.97; n = 48). For the 49 patients, the median turnaround time for each intraoperative PTH determination was 19 min (range, 14-40 min). The median decrease in PTH values from baseline was 88% (range, 33-99%). Thirty-seven patients required two PTH determinations, 7 required three, 4 had four, and 1 required five determinations. The average laboratory cost for the rapid intraoperative PTH assays was < $100 per patient (range, $55 to $113). Compared with the control group, the experimental group had significantly fewer frozen sections (1.4 vs 2.5; P < 0.0001), shorter hospital stays (17 discharged on the day of surgery vs none discharged on the day of surgery; P < 0.0001), greater use of local anesthesia (33% vs 0%; P < 0.001), and more unilateral, rather than bilateral neck explorations (65% vs 0%; P < 0.001).

CONCLUSIONS

The combination of intraoperative Turbo PTH assay and preoperative (99m)Tc-sestamibi scans can lead to significant decreases in laboratory and surgical pathology costs, hospital stays, and exposure to general anesthesia by facilitating concise parathyroidectomy surgery.

Effect of mycobacterial phospholipids on interaction of Mycobacterium tuberculosis with macrophages

This study demonstrates that pretreatment of macrophages with phosphatidylinositol, of either soya bean or mycobacterial origin, results in a down-regulation of the binding and uptake of Mycobacterium tuberculosis by the phagocytes. We also describe the novel observation that cardiolipin induces an increase in the binding and uptake of M. tuberculosis by macrophages. Neither phospholipid interacts with macrophages via the 2F8 epitope of scavenger receptor A, and treatment of macrophages with either phospholipid results in a down-regulation of CR3 function and tumor necrosis factor alpha production by the phagocyte. We have also shown that the ability of macrophages to interact with mycobacteria is greatly affected by an as yet unidentified product from the interaction of chloroform and polypropylene tubes.

Cationic antimicrobial peptides and their multifunctional role in the immune system

Many species of life contain cationic antimicrobial peptides as components of their immune systems. The antimicrobial activity of these peptides has been studied extensively, and many peptides have a broad spectrum of activity not only against gram-negative and gram-positive bacteria but also against antibiotic-resistant bacteria, fungi, viruses, and parasites. Such cationic antimicrobial peptides can also act in synergy with host molecules, such as other cationic peptides and proteins, lysozyme, and also conventional antibiotics, to kill microbes. It has been found that certain peptides are produced in large quantities at sites of infection/inflammation, and their expression can be induced by bacterial products such as endotoxic lipopolysaccharide (LPS) and proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). These peptides often have a high affinity for bacterial products, such as LPS, allowing them to modulate the host response and reduce the inflammatory response in sepsis. More recently, they have been found to interact directly with host cells to modulate the inflammatory process and innate defenses.

Interaction of polyphemusin I and structural analogs with bacterial membranes, lipopolysaccharide, and lipid monolayers

Three structural variants (PV5, PV7, and PV8) of the horseshoe crab cationic antimicrobial peptide polyphemusin I were designed with improved amphipathic profiles. Circular dichroism spectroscopy analysis indicated that in phosphate buffer polyphemusin I, PV7, and PV8 displayed the spectrum of a type II beta-turn-rich structure, but, like polyphemusin I, all three variants adopted a typical beta-sheet structure in an anionic lipid environment. Both polyphemusin I and variants were potent broad spectrum antimicrobials that were clearly bactericidal at their minimal inhibitory concentrations. The variants were moderately less active in vitro but more effective in animal models. Moreover, these variants exhibited delayed bacterial killing, whereas polyphemusin I killed Escherichia coli UB1005 within 5 min at 2.5 microg/mL. All the peptides showed similar abilities to bind to bacterial lipopolysaccharide (LPS) and permeabilize bacterial outer membranes. Consistent with this was the observation that all peptides significantly inhibited cytokine production by LPS-stimulated macrophages and penetrated polyanionic LPS monolayers to similar extents. None of the peptides had affinity for neutral lipids as evident from both tryptophan fluorescence spectroscopy and Langmuir monolayer analysis. As compared to polyphemusin I, all variants showed reduced ability to interact with anionic lipids, and the hemolytic activity of the variants was decreased by 2-4-fold. In contrast, polyphemusin I efficiently depolarized the cytoplasmic membrane of E. coli, as assessed using a membrane potential sensitive fluorescent dye 3,3-dipropylthiacarbocyanine (diSC(3)5) assay, but the variants showed a substantially delayed and decreased depolarizing ability. The coincident assessment of cell viability indicated that depolarization of the bacterial cytoplasmic membrane potential by polyphemusin I occurred prior to lethal damage to cells. Our data suggest that increase of amphipathicity of beta-sheet polyphemusin I generally resulted in variants with decreased activity for membranes. Interestingly, all variants showed an improved ability to protect mice both against infection by Pseudomonas aeruginosa and from endotoxaemia.