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Hogg A, Scullin C, Luo R, Currie A, Scott MG, McElnay JC. Do patient bedside medicine lockers result in a safer and faster medicine administration round? Eur J Hosp Pharm 2012. [DOI: 10.1136/ejhpharm-2012-000136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Aldeyab MA, Devine MJ, Flanagan P, Mannion M, Craig A, Scott MG, Harbarth S, Vernaz N, Davies E, Brazier JS, Smyth B, McElnay JC, Gilmore BF, Conlon G, Magee FA, Elhajji FWD, Small S, Edwards C, Funston C, Kearney MP. Multihospital outbreak of Clostridium difficile ribotype 027 infection: epidemiology and analysis of control measures. Infect Control Hosp Epidemiol 2011; 32:210-9. [PMID: 21460505 DOI: 10.1086/658333] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
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.
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Aldeyab MA, Kearney MP, McElnay JC, Magee FA, Conlon G, Gill D, Davey P, Muller A, Goossens H, Scott MG. A point prevalence survey of antibiotic prescriptions: benchmarking and patterns of use. Br J Clin Pharmacol 2011; 71:293-6. [PMID: 21219412 DOI: 10.1111/j.1365-2125.2010.03840.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
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.
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Scullin C, McElnay JC, Scott MG, Ryan M, Trouton TG, Baird S. Cost implications of the use of troponin I (cTnI) measurement to diagnose heart conditions. INTERNATIONAL JOURNAL OF PHARMACY PRACTICE 2011. [DOI: 10.1111/j.2042-7174.2001.tb01128.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Abstract
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Schober AH, McElnay JC, Scott MG, Kearney MP. The impact of hospital antimicrobial policy on the incidence of Clostridium difficile infection. INTERNATIONAL JOURNAL OF PHARMACY PRACTICE 2011. [DOI: 10.1111/j.2042-7174.2001.tb01123.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Abstract
Focal points
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Alahmadi YM, Aldeyab MA, McElnay JC, Scott MG, Darwish Elhajji FW, Magee FA, Dowds M, Edwards C, Fullerton L, Tate A, Kearney MP. Clinical and economic impact of contaminated blood cultures within the hospital setting. J Hosp Infect 2011; 77:233-6. [PMID: 21216032 DOI: 10.1016/j.jhin.2010.09.033] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 09/10/2010] [Indexed: 11/26/2022]
Abstract
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.
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Conlon G, Aldeyab MA, McElnay JC, Scott MG, Magee FA, Davies E, Gill D, Darwish Elhajji FW, Elshibly SM, Kearney MP. Improving and maintaining adherence with hospital antibiotic policies: a strategy for success. J Hosp Infect 2010; 77:88-9. [PMID: 21044809 DOI: 10.1016/j.jhin.2010.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 08/21/2010] [Indexed: 09/30/2022]
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Aldeyab MA, Kearney MP, Scott MG, Hanley J, McElnay JC. Health-Related Quality of Life after Intensive Care Unit Discharge: A Comparison between 2 Standard Antibiotic Regimens. Infect Control Hosp Epidemiol 2009; 30:807-8. [DOI: 10.1086/599001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Aldeyab MA, McElnay JC, Elshibly SM, Hughes CM, McDowell DA, McMahon MAS, Scott MG, Kearney MP. Evaluation of the efficacy of a conventional cleaning regimen in removing methicillin-resistant Staphylococcus aureus from contaminated surfaces in an intensive care unit. Infect Control Hosp Epidemiol 2009; 30:304-6. [PMID: 19215198 DOI: 10.1086/595964] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Burnett KM, Scott MG, Fleming GF, Clark CM, McElnay JC. Effects of an integrated medicines management program on medication appropriateness in hospitalized patients. Am J Health Syst Pharm 2009; 66:854-9. [DOI: 10.2146/ajhp080176] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Aldeyab MA, Hughes CM, Kearney MP, Scott MG, McDowell DA, Hanley J, McMahon MAS, Elshibly SM, Bailie R, McElnay JC. Comparison of the effect of ciprofloxacin and Tazocin® on the incidence of meticillin-resistant Staphylococcus aureus (MRSA) in an Intensive Care Unit. Int J Antimicrob Agents 2008; 32:499-504. [DOI: 10.1016/j.ijantimicag.2008.06.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Revised: 06/07/2008] [Accepted: 06/10/2008] [Indexed: 11/28/2022]
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Aldeyab MA, Monnet DL, López-Lozano JM, Hughes CM, Scott MG, Kearney MP, Magee FA, McElnay JC. Modelling the impact of antibiotic use and infection control practices on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus: a time-series analysis. J Antimicrob Chemother 2008; 62:593-600. [PMID: 18467307 DOI: 10.1093/jac/dkn198] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
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.
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Abstract
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.
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Scullin C, Scott MG, Gribbin M, McElnay JC. A HRG-based costing model for estimating pharmacy costs associated with surgical procedures. J Clin Pharm Ther 2004; 29:257-62. [PMID: 15153087 DOI: 10.1111/j.1365-2710.2004.00559.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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.
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Burnett KM, Scott MG, Kearney PM, Humphreys WG, McMillen RM. The identification of barriers preventing the successful implementation of a surgical prophylaxis protocol. PHARMACY WORLD & SCIENCE : PWS 2002; 24:182-7. [PMID: 12426962 DOI: 10.1023/a:1020565000571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
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.
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Al-Eidan FA, McElnay JC, Scott MG, McConnell JB. Management of Helicobacter pylori eradication--the influence of structured counselling and follow-up. Br J Clin Pharmacol 2002; 53:163-71. [PMID: 11851640 PMCID: PMC1874294 DOI: 10.1046/j.0306-5251.2001.01531.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2001] [Accepted: 09/21/2001] [Indexed: 12/20/2022] Open
Abstract
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.
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Pinckard JK, Zahn J, Ashby L, Parvin CA, Scott MG. Falsely increased i-STAT chloride results for blood samples with increased urea. Clin Chem 2001; 47:2064-6. [PMID: 11673386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Uhlmann EJ, Hock KG, Issitt C, Sneeringer MR, Cervelli DR, Gorman RT, Scott MG. Reference intervals for plasma cystatin C in healthy volunteers and renal patients, as measured by the Dade Behring BN II System, and correlation with creatinine. Clin Chem 2001; 47:2031-3. [PMID: 11673373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Foster K, Despotis G, Scott MG. Point-of-care testing. Cost issues and impact on hospital operations. Clin Lab Med 2001; 21:269-84. [PMID: 11396083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
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.
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Nowatzke WL, Parvin CA, Scott MG, Hock K, Cole TG. Correction of positive bias of the Roche Tina-quant II hemoglobin A1c (HbA1c) assay at low HbA1c percentages. Clin Chem 2001; 47:976-8. [PMID: 11325918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Johnson LR, Doherty G, Lairmore T, Moley JF, Brunt LM, Koenig J, Scott MG. Evaluation of the performance and clinical impact of a rapid intraoperative parathyroid hormone assay in conjunction with preoperative imaging and concise parathyroidectomy. Clin Chem 2001; 47:919-25. [PMID: 11325897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
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.
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Thorson LM, Doxsee D, Scott MG, Wheeler P, Stokes RW. Effect of mycobacterial phospholipids on interaction of Mycobacterium tuberculosis with macrophages. Infect Immun 2001; 69:2172-9. [PMID: 11254572 PMCID: PMC98144 DOI: 10.1128/iai.69.4.2172-2179.2001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2000] [Accepted: 01/16/2001] [Indexed: 11/20/2022] Open
Abstract
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.
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Scott MG, Hancock RE. Cationic antimicrobial peptides and their multifunctional role in the immune system. Crit Rev Immunol 2001; 20:407-31. [PMID: 11145218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
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.
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Miller ER, McElnay JC, Watt NT, Scott MG, McConnell BJ. Factors Affecting the Unplanned Hospital Readmission of Elderly Patients with Cardiovascular Disease. Clin Drug Investig 2001. [DOI: 10.2165/00044011-200121100-00005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Zhang L, Scott MG, Yan H, Mayer LD, Hancock RE. Interaction of polyphemusin I and structural analogs with bacterial membranes, lipopolysaccharide, and lipid monolayers. Biochemistry 2000; 39:14504-14. [PMID: 11087404 DOI: 10.1021/bi0011173] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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.
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